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/Bioelectrics/Bidomain/jrw-1998.xml

http://github.com/xyan075/examples
XML | 5333 lines | 4738 code | 290 blank | 305 comment | 0 complexity | 37f7f29a040fabee36fb7c2b8debc8e2 MD5 | raw file
   1<?xml version="1.0" encoding="iso-8859-1"?>
   2
   3
   4<!--  FILE :  jafri_rice_winslow_model_1998.xml
   5
   6CREATED :  September 2001
   7
   8LAST MODIFIED : 30th July 2003
   9
  10AUTHOR :  Catherine Lloyd
  11          Department of Engineering Science
  12          The University of Auckland
  13          
  14MODEL STATUS :  This model conforms to the CellML 1.0 Specification released on
  1510th August 2001, and the CellML Metadata 1.0 Specification released on 16th
  16January, 2002.
  17
  18DESCRIPTION :  This file contains a CellML description of the mammalian
  19ventricular action potential based on the Jafri-Rice-Winslow model, 1998.  This
  20model is a development of the LR-II model.  In particular, it makes an accurate
  21model of the membrane currents and adds a more sophisticated model of calcium
  22ion handling.
  23
  24CHANGES: 
  25  19/10/2001 - CML - Removed document type definition as this is declared as
  26                     optional according to the W3C recommendation.  
  27  24/10/2001 - CML - Made changes to some of the metadata, bringing them up to
  28                     date with the most recent working draft (26th September) of
  29                     the Metadata specification.
  30  07/12/2001 - CML - Changed tau_y_calculation after checking mathml using the
  31                     validator.
  32  04/01/2002 - CML - Altered some of the connections.
  33  21/01/2002 - AAC - Updated metadata to conform to the 16/1/02 CellML Metadata
  34                     1.0 Specification.
  35  25/02/2002 - CML - Corrected several equations.
  36  28/02/2002 - CML - Corrected several equations, variable units and their 
  37                     initial values.
  38  06/05/2002 - CML - Added some initial values.
  39  22/07/2002 - CML - Added more metadata.
  40  09/04/2003 - AAC - Added publication date information.  
  41  04/06/2003 - CML - Fixed MathML in a few components.
  42  30/07/2003 - CML - Altered a few equations.
  43-->
  44
  45<model
  46    name="jafri_rice_winslow_model_1998"
  47    cmeta:id="jafri_rice_winslow_model_1998"
  48    xmlns="http://www.cellml.org/cellml/1.0#"
  49    xmlns:cellml="http://www.cellml.org/cellml/1.0#"
  50    xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
  51  <rdf:RDF
  52      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  53      xmlns:cmeta="http://www.cellml.org/metadata/1.0#"
  54      xmlns:bqs="http://www.cellml.org/bqs/1.0#"
  55      xmlns:dc="http://purl.org/dc/elements/1.1/"
  56      xmlns:dcterms="http://purl.org/dc/terms/"
  57      xmlns:vCard="http://www.w3.org/2001/vcard-rdf/3.0#">
  58    <!--
  59      The following RDF block contains metadata that applies to this document
  60      as a whole, as indicated by the empty about attribute on the 
  61      <rdf:Description> element.
  62    -->
  63    <rdf:Description rdf:about="">
  64      <!--
  65        The Model Builder Metadata.  The Dublin Core "creator" element is used  
  66        to indicate the person who translated the model into CellML.
  67      -->
  68      <dc:creator rdf:parseType="Resource">
  69        <vCard:N rdf:parseType="Resource">
  70          <vCard:Family>Lloyd</vCard:Family>
  71          <vCard:Given>Catherine</vCard:Given>
  72          <vCard:Other>May</vCard:Other>
  73        </vCard:N>
  74        <vCard:EMAIL rdf:parseType="Resource">
  75          <rdf:value>c.lloyd@auckland.ac.nz</rdf:value>
  76          <rdf:type rdf:resource="http://imc.org/vCard/3.0#internet" />
  77        </vCard:EMAIL>
  78        <vCard:ORG rdf:parseType="Resource">
  79          <vCard:Orgname>The University of Auckland</vCard:Orgname>
  80          <vCard:Orgunit>The Bioengineering Research Group</vCard:Orgunit>
  81        </vCard:ORG>
  82      </dc:creator>
  83      
  84      <!--
  85        The Creation Date metadata. This is the date on which the model
  86        was translated into CellML.
  87      -->
  88      <dcterms:created rdf:parseType="Resource">
  89        <dcterms:W3CDTF>2001-09-24</dcterms:W3CDTF>
  90      </dcterms:created>
  91      
  92      <!--
  93        The Modification History metadata. This lists the changes that have been
  94        made to the document, who made the changes, and when they were made.
  95      -->
  96      <cmeta:modification rdf:parseType="Resource">
  97        <rdf:value>
  98          Corrected equations.
  99        </rdf:value>
 100        <cmeta:modifier rdf:parseType="Resource">
 101          <vCard:N rdf:parseType="Resource">
 102            <vCard:Family>Lloyd</vCard:Family>
 103            <vCard:Given>Catherine</vCard:Given>
 104            <vCard:Other>May</vCard:Other>
 105          </vCard:N>
 106        </cmeta:modifier>
 107        <dcterms:modified rdf:parseType="Resource"> 
 108          <dcterms:W3CDTF>2003-07-30</dcterms:W3CDTF>
 109        </dcterms:modified>
 110      </cmeta:modification>
 111      <cmeta:modification rdf:parseType="Resource">
 112        <rdf:value>
 113          Corrected equations: alpha_j_calculation and beta_j_calculation in 
 114          fast_sodium_current_j_gate, alpha_X_calculation and beta_X_calculation           in time_dependent_potassium_current_X_gate, and f_NaK_calculation and 
 115          i_NaK_calculation in Ca_release_current_from_JSR.
 116        </rdf:value>
 117        <cmeta:modifier rdf:parseType="Resource">
 118          <vCard:N rdf:parseType="Resource">
 119            <vCard:Family>Lloyd</vCard:Family>
 120            <vCard:Given>Catherine</vCard:Given>
 121            <vCard:Other>May</vCard:Other>
 122          </vCard:N>
 123        </cmeta:modifier>
 124        <dcterms:modified rdf:parseType="Resource"> 
 125          <dcterms:W3CDTF>2003-06-04</dcterms:W3CDTF>
 126        </dcterms:modified>
 127      </cmeta:modification>
 128      <cmeta:modification rdf:parseType="Resource">
 129        <rdf:value>
 130          Added some initial values from Penny Noble's documentation.
 131        </rdf:value>
 132        <cmeta:modifier rdf:parseType="Resource">
 133          <vCard:N rdf:parseType="Resource">
 134            <vCard:Family>Lloyd</vCard:Family>
 135            <vCard:Given>Catherine</vCard:Given>
 136            <vCard:Other>May</vCard:Other>
 137          </vCard:N>
 138        </cmeta:modifier>
 139        <dcterms:modified rdf:parseType="Resource">
 140          <dcterms:W3CDTF>2002-05-06</dcterms:W3CDTF>
 141        </dcterms:modified>
 142      </cmeta:modification>
 143      <cmeta:modification rdf:parseType="Resource">
 144        <rdf:value>
 145          Corrected several equations, variable units and their initial values.
 146        </rdf:value>
 147        <cmeta:modifier rdf:parseType="Resource">
 148          <vCard:N rdf:parseType="Resource">
 149            <vCard:Family>Lloyd</vCard:Family>
 150            <vCard:Given>Catherine</vCard:Given>
 151            <vCard:Other>May</vCard:Other>
 152          </vCard:N>
 153        </cmeta:modifier>
 154        <dcterms:modified rdf:parseType="Resource">
 155          <dcterms:W3CDTF>2002-02-28</dcterms:W3CDTF>
 156        </dcterms:modified>
 157      </cmeta:modification>  
 158      <cmeta:modification rdf:parseType="Resource">
 159        <rdf:value>
 160          Corrected several equations.
 161        </rdf:value>
 162        <cmeta:modifier rdf:parseType="Resource">
 163          <vCard:N rdf:parseType="Resource">
 164            <vCard:Family>Lloyd</vCard:Family>
 165            <vCard:Given>Catherine</vCard:Given>
 166            <vCard:Other>May</vCard:Other>
 167          </vCard:N>
 168        </cmeta:modifier>
 169        <dcterms:modified rdf:parseType="Resource">
 170          <dcterms:W3CDTF>2002-02-25</dcterms:W3CDTF>
 171        </dcterms:modified>
 172      </cmeta:modification>   
 173      <cmeta:modification rdf:parseType="Resource">
 174        <rdf:value>
 175          Altered some of the connections.
 176        </rdf:value>
 177        <cmeta:modifier rdf:parseType="Resource">
 178          <vCard:N rdf:parseType="Resource">
 179            <vCard:Family>Lloyd</vCard:Family>
 180            <vCard:Given>Catherine</vCard:Given>
 181            <vCard:Other>May</vCard:Other>
 182          </vCard:N>
 183        </cmeta:modifier>
 184        <dcterms:modified rdf:parseType="Resource">
 185          <dcterms:W3CDTF>2002-01-04</dcterms:W3CDTF>
 186        </dcterms:modified>
 187      </cmeta:modification>
 188      <cmeta:modification rdf:parseType="Resource">
 189        <rdf:value>
 190          Changed tau_y_calculation after checking mathml using the validator.
 191        </rdf:value>
 192        <cmeta:modifier rdf:parseType="Resource">
 193          <vCard:N rdf:parseType="Resource">
 194            <vCard:Family>Lloyd</vCard:Family>
 195            <vCard:Given>Catherine</vCard:Given>
 196            <vCard:Other>May</vCard:Other>
 197          </vCard:N>
 198        </cmeta:modifier>
 199        <dcterms:modified rdf:parseType="Resource">
 200          <dcterms:W3CDTF>2001-12-07</dcterms:W3CDTF>
 201        </dcterms:modified>
 202      </cmeta:modification>
 203      <cmeta:modification rdf:parseType="Resource">
 204        <rdf:value>
 205          Removed document type definition as this is declared as optional
 206          according to the W3C recommendation.
 207        </rdf:value>
 208        <cmeta:modifier rdf:parseType="Resource">
 209          <vCard:N rdf:parseType="Resource">
 210            <vCard:Family>Lloyd</vCard:Family>
 211            <vCard:Given>Catherine</vCard:Given>
 212            <vCard:Other>May</vCard:Other>
 213          </vCard:N>
 214        </cmeta:modifier>
 215        <dcterms:modified rdf:parseType="Resource">
 216          <dcterms:W3CDTF>2001-10-19</dcterms:W3CDTF>
 217        </dcterms:modified>
 218      </cmeta:modification>
 219      
 220      
 221      <!-- The Publisher metadata. -->
 222      <dc:publisher>
 223        The University of Auckland, Bioengineering Research Group
 224      </dc:publisher>
 225    </rdf:Description>
 226    
 227    <!--
 228      The following metadata refers to the model itself, as indicated by the
 229      reference to the ID "jafri_rice_winslow_model_1998", which is declared on 
 230      the <model> element.
 231    -->
 232    <rdf:Description rdf:about="#jafri_rice_winslow_model_1998">
 233      <!-- A human readable name for the model. -->
 234      <dc:title>
 235        The Jafri-Rice-Winslow Model for Calcium Regulation in the Ventricular
 236        Myocyte, 1997
 237      </dc:title>
 238      
 239      <!-- A comment regarding the model. -->
 240      <cmeta:comment rdf:parseType="Resource">
 241        <rdf:value>
 242          This is the CellML description of Jafri, Rice and Winslow's           
 243          mathematical model for calcium regulation in the ventricular myocyte. 
 244          It is based on an accurate model of the membrane currents and adds a  
 245          more sophisticated model of calcium handling.  The JRW model is based 
 246          on the LR-II model for ventricular action potentials, with several    
 247          modifications. 
 248        </rdf:value>
 249        <!-- The creator of the comment. -->
 250        <dc:creator rdf:parseType="Resource">
 251          <vCard:FN>Catherine Lloyd</vCard:FN>
 252        </dc:creator>
 253      </cmeta:comment>
 254      
 255      <!-- The model is relevant to all mammals. -->
 256      <cmeta:species>Mammalia</cmeta:species>
 257      
 258      <cmeta:bio_entity>Ventricular Myocyte</cmeta:bio_entity>
 259      
 260      <!-- 
 261        The CellML Metadata Specification recommends that bibliographic metadata
 262        is used to provide information about the original model reference.  The 
 263        "identifier" attribute on the "BibliographicReference" class provides an
 264        elegant way to identify a cited reference using a database identifier            such as Pubmed.  All associated data such as author, journal title,     
 265        date, etc can be looked up on the database.
 266      -->
 267      <bqs:reference rdf:parseType="Resource">
 268        <bqs:Pubmed_id>9512016</bqs:Pubmed_id>
 269        <bqs:JournalArticle rdf:parseType="Resource">
 270          <dc:creator>
 271            <rdf:Seq>
 272              <rdf:li rdf:parseType="Resource">
 273                <bqs:Person rdf:parseType="Resource">
 274                  <vCard:N rdf:parseType="Resource">
 275                    <vCard:Family>Jafri</vCard:Family>
 276                    <vCard:Given>M</vCard:Given>
 277                    <vCard:Other>Saleet</vCard:Other>
 278                  </vCard:N>
 279                </bqs:Person>
 280              </rdf:li>
 281              <rdf:li rdf:parseType="Resource">
 282                <bqs:Person rdf:parseType="Resource">
 283                  <vCard:N rdf:parseType="Resource">
 284                    <vCard:Family>Rice</vCard:Family>
 285                    <vCard:Given>John</vCard:Given>
 286                    <vCard:Other>Jeremy</vCard:Other>
 287                  </vCard:N>
 288                </bqs:Person>
 289              </rdf:li>
 290              <rdf:li rdf:parseType="Resource">
 291                <bqs:Person rdf:parseType="Resource">
 292                  <vCard:N rdf:parseType="Resource">
 293                    <vCard:Family>Winslow</vCard:Family>
 294                    <vCard:Given>Raimond</vCard:Given>
 295                    <vCard:Other>L</vCard:Other>
 296                  </vCard:N>
 297                </bqs:Person>
 298              </rdf:li>
 299            </rdf:Seq>
 300          </dc:creator>
 301          <dc:title>
 302            Cardiac Ca2+ Dynamics: The Roles of Ryanodine Receptor Adaptation 
 303            and Sarcoplasmic Reticulum Load
 304          </dc:title>
 305          <dcterms:issued rdf:parseType="Resource">
 306            <dcterms:W3CDTF>1998-03</dcterms:W3CDTF>
 307          </dcterms:issued>
 308          <bqs:Journal rdf:parseType="Resource">
 309            <dc:title>Biophysical Journal</dc:title>
 310          </bqs:Journal>
 311          <bqs:volume>74</bqs:volume>
 312          <bqs:first_page>1149</bqs:first_page>
 313          <bqs:last_page>1168</bqs:last_page>
 314        </bqs:JournalArticle>
 315      </bqs:reference>
 316    </rdf:Description>
 317  </rdf:RDF>
 318  
 319  <!--
 320    Below, we define some additional units for association with variables and
 321    constants within the model. The identifiers are fairly self-explanatory.
 322  -->
 323  <units name="ms">
 324    <unit prefix="milli" units="second" />
 325  </units>
 326  
 327  <units name="per_ms">
 328    <unit prefix="milli" units="second" exponent="-1" />
 329  </units>
 330  
 331  <units name="per_mm">
 332    <unit prefix="milli" units="metre" exponent="-1" />
 333  </units>
 334  
 335  <units name="mV">
 336    <unit prefix="milli" units="volt" />
 337  </units>
 338
 339  <units name="per_mV">
 340    <unit prefix="milli" units="volt" exponent="-1" />
 341  </units>
 342  
 343  <units name="per_mV_ms">
 344    <unit units="mV" exponent="-1" />
 345    <unit units="ms" exponent="-1" />
 346  </units>
 347  
 348  <units name="mS_per_mm2">
 349    <unit prefix="milli" units="siemens" />
 350    <unit prefix="milli" units="metre" exponent="-2" />
 351  </units>
 352  
 353  <units name="mm2">
 354    <unit prefix="milli" units="metre" exponent="2" />
 355  </units>
 356  
 357  <units name="mM">
 358    <unit prefix="nano" units="mole" />
 359    <unit prefix="milli" units="metre" exponent="-3" />
 360  </units>
 361  
 362  <units name="mM_per_ms">
 363    <unit units="mM" />
 364    <unit units="ms" exponent="-1" />
 365  </units>
 366  
 367  <units name="per_mM_per_ms">
 368    <unit units="mM" exponent="-1" />
 369    <unit units="ms" exponent="-1" />
 370  </units>
 371  
 372  <units name="per_mM3_per_ms">
 373    <unit units="mM" exponent="-3" />
 374    <unit units="ms" exponent="-1" />
 375  </units>
 376  
 377  <units name="per_mM4_per_ms">
 378    <unit units="mM" exponent="-4" />
 379    <unit units="ms" exponent="-1" />
 380  </units>
 381    
 382  <units name="uF_per_mm2">
 383    <unit prefix="micro" units="farad" />
 384    <unit prefix="milli" units="metre" exponent="-2" />
 385  </units>
 386
 387  <units name="uA_per_mm2">
 388    <unit prefix="micro" units="ampere" />
 389    <unit prefix="milli" units="metre" exponent="-2" />
 390  </units>
 391    
 392  <units name="mm_per_ms">
 393    <unit prefix="milli" units="metre" />
 394    <unit units="ms" exponent="-1" />
 395  </units>
 396  
 397  <units name="gas_constant_units">
 398    <unit prefix="pico" units="joule" />
 399    <unit prefix="nano" units="mole" exponent="-1" />
 400    <unit units="kelvin" exponent="-1" />
 401  </units>
 402  
 403  <units name="faradays_constant_units">
 404    <unit prefix="nano" units="coulomb" />
 405    <unit prefix="nano" units="mole" exponent="-1" />
 406  </units>
 407  
 408  
 409  <!--
 410    The "environment" component is used to declare variables that are used by
 411    all or most of the other components, in this case just "time".
 412  -->
 413  <component name="environment">
 414    <variable name="time" public_interface="out" units="ms" />
 415  </component>
 416
 417
 418  <!--
 419    The "membrane" component is really the `root' node of our model.
 420    It defines the action potential variable "V" among other things.
 421  -->
 422  <component name="membrane" cmeta:id="membrane">
 423    <rdf:RDF
 424      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 425      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 426      <rdf:Description rdf:about="#membrane">
 427        <cmeta:comment rdf:parseType="Resource">
 428          <rdf:value>
 429            The main component of the model which defines the action potential.
 430          </rdf:value>
 431        </cmeta:comment>
 432      </rdf:Description>
 433    </rdf:RDF>
 434
 435    <!-- These variables are defined here and used in other components. -->
 436    <variable
 437        name="V" public_interface="out"
 438        initial_value="-84.1638" units="mV" />
 439    <variable
 440        name="R" public_interface="out"
 441        initial_value="8.3145e3" units="gas_constant_units" />
 442    <variable
 443        name="T" public_interface="out"
 444        initial_value="310.0" units="kelvin" />
 445    <variable
 446        name="F" public_interface="out"
 447        initial_value="9.6845e4" units="faradays_constant_units" />
 448         
 449    <!-- These variables are imported from other components. -->
 450    <variable name="time" public_interface="in" units="ms" />
 451    <variable name="i_Na" public_interface="in" units="uA_per_mm2" />
 452    <variable name="i_Ca_L_Ca" public_interface="in" units="uA_per_mm2" />
 453    <variable name="i_Ca_L_K" public_interface="in" units="uA_per_mm2" />
 454    <variable name="i_K" public_interface="in" units="uA_per_mm2" />
 455    <variable name="i_K1" public_interface="in" units="uA_per_mm2" />
 456    <variable name="i_NaCa" public_interface="in" units="uA_per_mm2" />
 457    <variable name="i_Kp" public_interface="in" units="uA_per_mm2" />
 458    <variable name="i_p_Ca" public_interface="in" units="uA_per_mm2" />
 459    <variable name="i_Na_b" public_interface="in" units="uA_per_mm2" />
 460    <variable name="i_Ca_b" public_interface="in" units="uA_per_mm2" />
 461    <variable name="i_NaK" public_interface="in" units="uA_per_mm2" />
 462    <variable name="i_ns_Ca" public_interface="in" units="uA_per_mm2" />
 463    
 464    <!-- These variables is defined here and only used internally. -->
 465    <variable name="Cm" initial_value="0.01" units="uF_per_mm2" />
 466    <variable name="I_stim" units="uA_per_mm2" />
 467    
 468    <rdf:RDF
 469      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 470      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 471      <rdf:Description rdf:about="#membrane_voltage_diff_eq">
 472        <cmeta:comment rdf:parseType="Resource">
 473          <rdf:value>
 474            The kinetics of the transmembrane potential, defined as the sum of
 475            all the sarcolemmal currents and an applied stimulus current.
 476          </rdf:value>
 477        </cmeta:comment>
 478      </rdf:Description>
 479    </rdf:RDF>
 480    <math xmlns="http://www.w3.org/1998/Math/MathML"
 481      cmeta:id="membrane_voltage_diff_eq">
 482      <apply id="membrane_voltage_diff_eq"><eq />
 483        <apply><diff />
 484          <bvar><ci> time </ci></bvar>
 485          <ci> V </ci>
 486        </apply>
 487        <apply><divide />
 488          <apply><minus />
 489            <ci>I_stim</ci>
 490            <apply><plus />
 491              <ci> i_Na </ci>
 492              <ci> i_Ca_L_Ca </ci>
 493              <ci> i_Ca_L_K </ci>
 494              <ci> i_K </ci>
 495              <ci> i_NaCa </ci>
 496              <ci> i_K1 </ci>
 497              <ci> i_Kp </ci>
 498              <ci> i_p_Ca </ci>
 499              <ci> i_Na_b </ci>
 500              <ci> i_Ca_b </ci>
 501              <ci> i_NaK </ci>
 502              <ci> i_ns_Ca </ci>
 503            </apply>
 504          </apply>
 505          <ci> Cm </ci>
 506        </apply>
 507      </apply>
 508    </math>
 509    <rdf:RDF
 510      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 511      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 512      <rdf:Description rdf:about="#IStim_for_cmiss_eq">
 513        <cmeta:comment rdf:parseType="Resource">
 514          <rdf:value>
 515            This is a dummy equation that we simply use to make grabbing the
 516            value in CMISS much easier.
 517          </rdf:value>
 518        </cmeta:comment>
 519      </rdf:Description>
 520    </rdf:RDF>
 521    <variable name="IStimC" units="uA_per_mm2" public_interface="out"/>
 522    <math xmlns="http://www.w3.org/1998/Math/MathML" cmeta:id="IStim_for_cmiss_eq">
 523      <apply id="IStim_for_cmiss"><eq/>
 524        <ci>IStimC</ci>
 525        <ci>I_stim</ci>
 526      </apply>
 527    </math>
 528  </component>
 529  
 530  <component name="fast_sodium_current" cmeta:id="fast_sodium_current">
 531    <rdf:RDF
 532      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 533      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 534      <rdf:Description rdf:about="#fast_sodium_current">
 535        <cmeta:comment rdf:parseType="Resource">
 536          <rdf:value>
 537            The fast sodium current component contains the differential
 538            equations governing the influx of sodium ions through the cell
 539            surface membrane into the cell.
 540          </rdf:value>
 541        </cmeta:comment>
 542      </rdf:Description>
 543    </rdf:RDF>
 544
 545    <!-- These variables are defined here and used in other components. -->
 546    <variable name="i_Na" public_interface="out" units="uA_per_mm2" />
 547    <variable name="E_Na" public_interface="out" units="mV" />
 548    
 549    <!-- This variable is defined here and only used internally. -->
 550    <variable name="g_Na" initial_value="0.128" units="mS_per_mm2" />
 551    
 552    <!-- 
 553      Time is imported from the environment, and membrane potential is          
 554      imported from the membrane component.  These variables are used in the    
 555      "sodium_current" parent component, which also acts as an interface,       
 556      passing the variables to its encapsulated gate components. 
 557    -->
 558    <variable
 559        name="time" public_interface="in"
 560        private_interface="out" units="ms" />
 561    <variable
 562        name="V" public_interface="in"
 563        private_interface="out" units="mV" />
 564    <variable name="R" public_interface="in" units="gas_constant_units" />
 565    <variable name="T" public_interface="in" units="kelvin" />
 566    <variable name="F" public_interface="in" units="faradays_constant_units" />
 567    <variable name="Nai" public_interface="in" units="mM" />
 568    <variable name="Nao" public_interface="in" units="mM" />
 569    
 570    <!-- These variables are imported from encapsulated components. -->
 571    <variable name="m" private_interface="in" units="dimensionless" />
 572    <variable name="h" private_interface="in" units="dimensionless" />
 573    <variable name="j" private_interface="in" units="dimensionless" />
 574    
 575    <rdf:RDF
 576      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 577      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 578      <rdf:Description rdf:about="#i_Na_calculation_eq">
 579        <cmeta:comment rdf:parseType="Resource">
 580          <rdf:value>
 581            Calculation of the fast sodium current using the three
 582            Hodkin-Huxley type voltage-dependent gating variables m, h, and j.
 583          </rdf:value>
 584        </cmeta:comment>
 585      </rdf:Description>
 586    </rdf:RDF>
 587    <math xmlns="http://www.w3.org/1998/Math/MathML"
 588      cmeta:id="i_Na_calculation_eq">
 589      <apply id="i_Na_calculation"><eq />
 590        <ci> i_Na </ci>
 591        <apply><times />
 592          <ci> g_Na </ci>
 593          <apply><power />
 594            <ci> m </ci>
 595            <cn cellml:units="dimensionless"> 3.0 </cn>
 596          </apply>
 597          <ci> h </ci>
 598          <ci> j </ci>
 599          <apply><minus />
 600            <ci> V </ci>
 601            <ci> E_Na </ci>
 602          </apply>
 603        </apply>
 604      </apply>
 605    </math>
 606      
 607    <rdf:RDF
 608      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 609      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 610      <rdf:Description rdf:about="#E_Na_calculation_eq">
 611        <cmeta:comment rdf:parseType="Resource">
 612          <rdf:value>
 613            The sodium reversal potential.
 614          </rdf:value>
 615        </cmeta:comment>
 616      </rdf:Description>
 617    </rdf:RDF>
 618    <math xmlns="http://www.w3.org/1998/Math/MathML"
 619      cmeta:id="E_Na_calculation_eq">
 620      <apply id="E_Na_calculation"><eq />
 621        <ci> E_Na </ci>
 622        <apply><times />
 623          <apply><divide />
 624            <apply><times />
 625              <ci> R </ci>
 626              <ci> T </ci>
 627            </apply>
 628            <ci> F </ci>
 629          </apply>
 630          <apply><ln />
 631            <apply><divide />
 632              <ci> Nao </ci>
 633              <ci> Nai </ci>
 634            </apply>
 635          </apply>
 636        </apply>
 637      </apply>
 638    </math>
 639  </component>
 640     
 641  <!--
 642    The "fast_sodium_current_m_gate" is the m gate encapsulated inside the fast 
 643    sodium current. 
 644  -->
 645  <component name="fast_sodium_current_m_gate"
 646    cmeta:id="fast_sodium_current_m_gate">
 647    <rdf:RDF
 648      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 649      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 650      <rdf:Description rdf:about="#fast_sodium_current_m_gate">
 651        <cmeta:comment rdf:parseType="Resource">
 652          <rdf:value>
 653            The voltage-dependent activation gate for the fast sodium current -
 654            the m gate.
 655          </rdf:value>
 656        </cmeta:comment>
 657      </rdf:Description>
 658    </rdf:RDF>
 659    
 660    <!-- This variable is defined here and used in other components. -->
 661    <variable
 662        name="m" public_interface="out"
 663        initial_value="0.0328302" units="dimensionless" />
 664        
 665    <!-- These variables are defined here and only used internally. -->
 666    <variable name="alpha_m" units="per_ms" />
 667    <variable name="beta_m" units="per_ms" />
 668
 669    <!-- 
 670      These variables are imported from the environment and the membrane via    
 671      the "fast_sodium_current" component.
 672    -->
 673    <variable name="V" public_interface="in" units="mV" />
 674    <variable name="time" public_interface="in" units="ms" />
 675   
 676    <rdf:RDF
 677      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 678      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 679      <rdf:Description rdf:about="#alpha_m_calculation_eq">
 680        <cmeta:comment rdf:parseType="Resource">
 681          <rdf:value>
 682            The opening rate of the m gate.
 683          </rdf:value>
 684        </cmeta:comment>
 685      </rdf:Description>
 686    </rdf:RDF>
 687    <math xmlns="http://www.w3.org/1998/Math/MathML"
 688      cmeta:id="alpha_m_calculation_eq">
 689      <apply id="alpha_m_calculation"><eq />
 690        <ci> alpha_m </ci>
 691        <apply><divide />
 692          <apply><times />
 693            <cn cellml:units="per_mV_ms"> 0.32 </cn>
 694            <apply><plus />
 695              <ci> V </ci>
 696              <cn cellml:units="mV"> 47.13 </cn>
 697            </apply>
 698          </apply>
 699          <apply><minus />
 700            <cn cellml:units="dimensionless"> 1.0 </cn>
 701            <apply><exp />
 702              <apply><times />
 703                <cn cellml:units="per_mV"> -0.1 </cn>
 704                <apply><plus />
 705                  <ci> V </ci>
 706                  <cn cellml:units="mV"> 47.13 </cn>
 707                </apply>
 708              </apply>
 709            </apply>
 710          </apply>
 711        </apply>
 712      </apply>
 713    </math>
 714      
 715    <rdf:RDF
 716      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 717      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 718      <rdf:Description rdf:about="#beta_m_calculation_eq">
 719        <cmeta:comment rdf:parseType="Resource">
 720          <rdf:value>
 721            The closing rate of the m gate.
 722          </rdf:value>
 723        </cmeta:comment>
 724      </rdf:Description>
 725    </rdf:RDF>
 726    <math xmlns="http://www.w3.org/1998/Math/MathML"
 727      cmeta:id="beta_m_calculation_eq">
 728      <apply id="beta_m_calculation"><eq />
 729        <ci> beta_m </ci>
 730        <apply><times />
 731          <cn cellml:units="per_ms"> 0.08 </cn>
 732          <apply><exp />
 733            <apply><divide />
 734              <apply><minus />
 735                <ci> V </ci>
 736              </apply>
 737              <cn cellml:units="mV"> 11.0 </cn>
 738            </apply>
 739          </apply>
 740        </apply>
 741      </apply>
 742    </math>
 743      
 744    <rdf:RDF
 745      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 746      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 747      <rdf:Description rdf:about="#dm_dt_eq">
 748        <cmeta:comment rdf:parseType="Resource">
 749          <rdf:value>
 750            The kinetics of the m gate.
 751          </rdf:value>
 752        </cmeta:comment>
 753      </rdf:Description>
 754    </rdf:RDF>
 755    <math xmlns="http://www.w3.org/1998/Math/MathML"
 756      cmeta:id="dm_dt_eq">
 757      <apply id="dm_dt"><eq />
 758        <apply><diff />
 759          <bvar><ci> time </ci></bvar>
 760          <ci> m </ci>
 761        </apply>
 762        <apply><minus />
 763          <apply><times />
 764            <ci> alpha_m </ci>
 765            <apply><minus />
 766              <cn cellml:units="per_mV"> 1.0 </cn>
 767              <ci> m </ci>
 768            </apply>
 769          </apply>
 770          <apply><times />
 771            <ci> beta_m </ci>
 772            <ci> m </ci>
 773          </apply>
 774        </apply>
 775      </apply>
 776    </math>
 777  </component>
 778  
 779  <!--
 780    The "fast_sodium_current_h_gate" component is the h gate encapsulated in
 781    the fast sodium current.
 782  -->
 783  <component name="fast_sodium_current_h_gate"
 784    cmeta:id="fast_sodium_current_h_gate">
 785    <rdf:RDF
 786      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 787      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 788      <rdf:Description rdf:about="#fast_sodium_current_h_gate">
 789        <cmeta:comment rdf:parseType="Resource">
 790          <rdf:value>
 791            The voltage-dependent inactivation gate for the fast sodium current
 792            - the h gate.
 793          </rdf:value>
 794        </cmeta:comment>
 795      </rdf:Description>
 796    </rdf:RDF>
 797
 798    <!-- This variable is defined here and used in other components. -->
 799    <variable
 800        name="h" public_interface="out"
 801        initial_value="0.988354" units="dimensionless" />
 802        
 803    <!-- These variables are defined here and only used internally. -->
 804    <variable name="alpha_h" units="per_ms" />
 805    <variable name="beta_h" units="per_ms" />
 806
 807    <!-- 
 808      These variables are imported from the environment and the membrane via    
 809      the "fast_sodium_current" component.  
 810    -->
 811    <variable name="V" public_interface="in" units="mV" />
 812    <variable name="time" public_interface="in" units="ms" />
 813    
 814    <rdf:RDF
 815      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 816      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 817      <rdf:Description rdf:about="#alpha_h_calculation_eq">
 818        <cmeta:comment rdf:parseType="Resource">
 819          <rdf:value>
 820            The opening rate of the h gate.
 821          </rdf:value>
 822        </cmeta:comment>
 823      </rdf:Description>
 824    </rdf:RDF>
 825    <math xmlns="http://www.w3.org/1998/Math/MathML"
 826      cmeta:id="alpha_h_calculation_eq">
 827      <apply id="alpha_h_calculation"><eq />
 828        <ci> alpha_h </ci>
 829        <piecewise>
 830          <piece>
 831            <apply><times />
 832              <cn cellml:units="per_ms"> 0.135 </cn>
 833              <apply><exp />
 834                <apply><divide />
 835                  <apply><plus />
 836                    <cn cellml:units="mV"> 80.0 </cn>
 837                    <ci> V </ci>
 838                  </apply>
 839                  <cn cellml:units="mV"> -6.8 </cn>
 840                </apply>
 841              </apply>
 842            </apply>
 843            <apply><lt />
 844              <ci> V </ci> 
 845              <cn cellml:units="mV"> -40.0 </cn>
 846            </apply>
 847          </piece>
 848          <otherwise>
 849            <cn cellml:units="per_ms"> 0.0 </cn>
 850          </otherwise>
 851        </piecewise>
 852      </apply>
 853    </math>
 854       
 855    <rdf:RDF
 856      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 857      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 858      <rdf:Description rdf:about="#beta_h_calculation_eq">
 859        <cmeta:comment rdf:parseType="Resource">
 860          <rdf:value>
 861            The closing rate of the h gate.
 862          </rdf:value>
 863        </cmeta:comment>
 864      </rdf:Description>
 865    </rdf:RDF>
 866    <math xmlns="http://www.w3.org/1998/Math/MathML"
 867      cmeta:id="beta_h_calculation_eq">
 868      <apply id="beta_h_calculation"><eq />
 869        <ci> beta_h </ci>
 870        <piecewise>
 871          <piece>
 872            <apply><plus />
 873              <apply><times />
 874                <cn cellml:units="per_ms"> 3.56 </cn>
 875                <apply><exp />
 876                  <apply><times />
 877                    <cn cellml:units="mV"> 0.079 </cn>
 878                    <ci> V </ci>
 879                  </apply>
 880                </apply>
 881              </apply>
 882              <apply><times />
 883                <cn cellml:units="per_ms"> 310000.0 </cn>
 884                <apply><exp />
 885                  <apply><times />
 886                    <cn cellml:units="per_mV"> 0.35 </cn>
 887                    <ci> V </ci>
 888                  </apply>
 889                </apply>
 890              </apply>
 891            </apply>
 892            <apply><lt />
 893              <ci> V </ci>
 894              <cn cellml:units="mV"> -40.0 </cn>
 895            </apply>
 896          </piece>
 897          <otherwise>
 898            <apply><divide />
 899              <cn cellml:units="dimensionless"> 1.0 </cn>
 900              <apply><times />
 901                <cn cellml:units="ms"> 0.13 </cn>
 902                <apply><plus />
 903                  <cn cellml:units="dimensionless"> 1.0 </cn>
 904                  <apply><exp />
 905                    <apply><divide />
 906                      <apply><plus />
 907                        <ci> V </ci>
 908                        <cn cellml:units="mV"> 10.66 </cn>
 909                      </apply>
 910                      <cn cellml:units="mV"> -11.1 </cn>
 911                    </apply>
 912                  </apply>
 913                </apply>
 914              </apply>
 915            </apply>
 916          </otherwise>
 917        </piecewise>
 918      </apply>
 919    </math>
 920       
 921    <rdf:RDF
 922      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 923      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 924      <rdf:Description rdf:about="#dh_dt_eq">
 925        <cmeta:comment rdf:parseType="Resource">
 926          <rdf:value>
 927            The kinetics of the h gate.
 928          </rdf:value>
 929        </cmeta:comment>
 930      </rdf:Description>
 931    </rdf:RDF>
 932    <math xmlns="http://www.w3.org/1998/Math/MathML"
 933      cmeta:id="dh_dt_eq">
 934      <apply id="dh_dt"><eq />
 935        <apply><diff />
 936          <bvar><ci> time </ci></bvar>
 937          <ci> h </ci>
 938        </apply>
 939        <apply><minus />
 940          <apply><times />
 941            <ci> alpha_h </ci>
 942            <apply><minus />
 943              <cn cellml:units="dimensionless"> 1.0 </cn>
 944              <ci> h </ci>
 945            </apply>
 946          </apply>
 947          <apply><times />
 948            <ci> beta_h </ci>
 949            <ci> h </ci>
 950          </apply>
 951        </apply>
 952      </apply>
 953    </math>
 954  </component>
 955  
 956  <!--
 957    The "fast_sodium_current_j_gate" component is the j gate encapsulated in
 958    the fast sodium current.
 959  -->
 960  <component name="fast_sodium_current_j_gate"
 961    cmeta:id="fast_sodium_current_j_gate">
 962    <rdf:RDF
 963      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 964      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 965      <rdf:Description rdf:about="#fast_sodium_current_j_gate">
 966        <cmeta:comment rdf:parseType="Resource">
 967          <rdf:value>
 968            The voltage-dependent slow inactivation gate for the fast sodium
 969            current - the j gate.
 970          </rdf:value>
 971        </cmeta:comment>
 972      </rdf:Description>
 973    </rdf:RDF>
 974
 975    <!-- This variable is defined here and used in other components. -->
 976    <variable
 977        name="j" public_interface="out"
 978        initial_value="0.992540" units="dimensionless" />
 979        
 980    <!-- These variables are defined here and only used internally. -->
 981    <variable name="alpha_j" units="per_ms" />
 982    <variable name="beta_j" units="per_ms" />
 983    
 984    <!-- 
 985      These variables are imported from the environment and the membrane via    
 986      the "fast_sodium_current" component.  
 987    -->
 988    <variable name="V" public_interface="in" units="mV" />
 989    <variable name="time" public_interface="in" units="ms" />
 990    
 991    <rdf:RDF
 992      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 993      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
 994      <rdf:Description rdf:about="#alpha_j_calculation_eq">
 995        <cmeta:comment rdf:parseType="Resource">
 996          <rdf:value>
 997            The opening rate of the j gate.
 998          </rdf:value>
 999        </cmeta:comment>
1000      </rdf:Description>
1001    </rdf:RDF>
1002    <math xmlns="http://www.w3.org/1998/Math/MathML"
1003      cmeta:id="alpha_j_calculation_eq">
1004      <apply id="alpha_j_calculation"><eq />
1005        <ci> alpha_j </ci>
1006        <piecewise>
1007          <piece>
1008            <apply><times />
1009              <apply><minus />
1010                <apply><times />
1011                  <cn cellml:units="per_mV_ms"> -127140.0 </cn>
1012                  <apply><exp />
1013                    <apply><times /> 
1014                      <cn cellml:units="per_mV"> 0.2444 </cn>
1015                      <ci> V </ci>
1016                    </apply>
1017                  </apply>
1018                </apply>
1019                <apply><times />
1020                  <cn cellml:units="per_mV_ms"> 0.00003474 </cn>
1021                  <apply><exp />
1022                    <apply><times />
1023                      <cn cellml:units="per_mV"> -0.04391 </cn>
1024                      <ci> V </ci>
1025                    </apply>
1026                  </apply>
1027                </apply>
1028              </apply>
1029              <apply><divide />
1030                <apply><plus />
1031                  <ci> V </ci>
1032                  <cn cellml:units="mV"> 37.78 </cn>
1033                </apply>
1034                <apply><plus />
1035                  <cn cellml:units="dimensionless"> 1.0 </cn>
1036                  <apply><exp />
1037                    <apply><times />
1038                      <cn cellml:units="per_mV"> 0.311 </cn>
1039                      <apply><plus />
1040                        <ci> V </ci>
1041                        <cn cellml:units="mV"> 79.23 </cn>
1042                      </apply>
1043                    </apply>
1044                  </apply>
1045                </apply>
1046              </apply>
1047            </apply>
1048            <apply><lt />
1049              <ci> V </ci>
1050              <cn cellml:units="mV"> -40.0 </cn>
1051            </apply>
1052          </piece>
1053          <otherwise>
1054            <cn cellml:units="per_ms"> 0.0 </cn>
1055          </otherwise>
1056        </piecewise>
1057      </apply>
1058    </math>
1059       
1060    <rdf:RDF
1061      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1062      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1063      <rdf:Description rdf:about="#beta_j_calculation_eq">
1064        <cmeta:comment rdf:parseType="Resource">
1065          <rdf:value>
1066            The closing rate of the j gate.
1067          </rdf:value>
1068        </cmeta:comment>
1069      </rdf:Description>
1070    </rdf:RDF>
1071    <math xmlns="http://www.w3.org/1998/Math/MathML"
1072      cmeta:id="beta_j_calculation_eq">
1073      <apply id="beta_j_calculation"><eq />
1074        <ci> beta_j </ci>
1075        <piecewise>
1076          <piece>
1077            <apply><times />
1078              <cn cellml:units="per_ms"> 0.1212 </cn>
1079              <apply><divide />
1080                <apply><exp />
1081                  <apply><times />
1082                    <cn cellml:units="per_mV"> -0.01052 </cn>
1083                    <ci> V </ci>
1084                  </apply>
1085                </apply>
1086                <apply><plus />
1087                  <cn cellml:units="dimensionless"> 1.0 </cn>
1088                  <apply><exp />
1089                    <apply><times />
1090                      <cn cellml:units="per_mV"> -0.1378 </cn>
1091                      <apply><plus />       
1092                        <ci> V </ci>
1093                        <cn cellml:units="mV"> 40.14 </cn>
1094                      </apply>
1095                    </apply>
1096                  </apply>
1097                </apply>
1098              </apply>
1099            </apply>
1100            <apply><lt />
1101              <ci> V </ci>
1102              <cn cellml:units="mV"> -40.0 </cn>
1103            </apply>
1104          </piece>
1105          <otherwise>
1106            <apply><times />
1107              <cn cellml:units="per_ms"> 0.3 </cn>
1108              <apply><divide />
1109                <apply><exp />
1110                  <apply><times />
1111                    <cn cellml:units="per_mV"> -0.0000002535 </cn>
1112                    <ci> V </ci>                                                
1113                  </apply>
1114                </apply>
1115                <apply><plus />
1116                  <cn cellml:units="dimensionless"> 1.0 </cn>
1117                  <apply><exp />
1118                    <apply><times />
1119                      <cn cellml:units="per_mV"> -0.1 </cn>
1120                      <apply><plus />
1121                        <ci> V </ci>
1122                        <cn cellml:units="mV"> 32.0 </cn>
1123                      </apply>
1124                    </apply>
1125                  </apply>
1126                </apply>
1127              </apply>
1128            </apply>                                                            
1129          </otherwise> 
1130        </piecewise>
1131      </apply>
1132    </math>
1133       
1134    <rdf:RDF
1135      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1136      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1137      <rdf:Description rdf:about="#dj_dt_eq">
1138        <cmeta:comment rdf:parseType="Resource">
1139          <rdf:value>
1140            The kinetics of the j gate.
1141          </rdf:value>
1142        </cmeta:comment>
1143      </rdf:Description>
1144    </rdf:RDF>
1145    <math xmlns="http://www.w3.org/1998/Math/MathML"
1146      cmeta:id="dj_dt_eq">
1147      <apply id="dj_dt"><eq />
1148        <apply><diff />
1149          <bvar><ci> time </ci></bvar>
1150          <ci> j </ci>
1151        </apply>
1152        <apply><minus />
1153          <apply><times />
1154            <ci> alpha_j </ci>
1155            <apply><minus />
1156              <cn cellml:units="dimensionless"> 1.0 </cn>
1157              <ci> j </ci>
1158            </apply>
1159          </apply>
1160          <apply><times />
1161            <ci> beta_j </ci>
1162            <ci> j </ci>
1163          </apply>
1164        </apply>
1165      </apply>
1166    </math>
1167  </component>
1168  
1169  
1170  <component name="L_type_Ca_channel" cmeta:id="L_type_Ca_channel">
1171    <rdf:RDF
1172      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1173      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1174      <rdf:Description rdf:about="#L_type_Ca_channel">
1175        <cmeta:comment rdf:parseType="Resource">
1176          <rdf:value>
1177            The JWR model creates a new mathematical model to describe the
1178            L-type calcium channel that is based on the experimentally observed
1179            mode-switching behaviour of the channel. Inactivation occurs as
1180            calcium ion binding induces the channel to switch (from mode normal)
1181            to a mode in which transitions to open states are extremely slow
1182            (mode Ca). The channel has one voltage inactivation gate, y. As well
1183            as Ca, the channel is assumed permeable to K ions also.
1184          </rdf:value>
1185        </cmeta:comment>
1186      </rdf:Description>
1187    </rdf:RDF>
1188
1189    <!-- These variables are defined here and used in other components. -->
1190    <variable name="i_Ca_L_Ca" public_interface="out" units="uA_per_mm2" />
1191    <variable name="i_Ca_L_K" public_interface="out" units="uA_per_mm2" />
1192    
1193    <!-- These variables are defined here and only used internally. -->
1194    <variable name="P_Ca" initial_value="33.75e-6" units="mm_per_ms" />
1195    <variable name="P_K" initial_value="1.0e-9" units="mm_per_ms" />
1196    <variable name="p_k" units="mm_per_ms" />
1197    <variable name="i_Ca_L_Ca_half" initial_value="-4.58e-3" units="uA_per_mm2" />
1198    <variable name="i_Ca_L_Ca_max" units="uA_per_mm2" />
1199    <variable name="O" initial_value="9.84546e-21" units="dimensionless" />
1200    <variable name="O_Ca" initial_value="0.0" units="dimensionless" />
1201    <variable name="alpha" units="per_ms" />
1202    <variable name="beta" units="per_ms" />
1203    <variable name="gamma" units="per_ms" />
1204    <variable name="alpha_a" units="per_ms" />
1205    <variable name="beta_b" units="per_ms" />
1206    <variable name="a" initial_value="2.0" units="dimensionless" />
1207    <variable name="b" initial_value="2.0" units="dimensionless" />
1208    <variable name="g" initial_value="2.0" units="per_ms" />
1209    <variable name="f" initial_value="0.3" units="per_ms" />
1210    <variable name="g_" initial_value="0.0" units="per_ms" />
1211    <variable name="f_" initial_value="0.0" units="per_ms" />
1212    <variable name="omega" initial_value="0.01" units="per_ms" />
1213    <variable name="C0" initial_value="0.997208" units="dimensionless" />
1214    <variable name="C1" initial_value="6.38897e-5" units="dimensionless" />
1215    <variable name="C2" initial_value="1.535e-9" units="dimensionless" />
1216    <variable name="C3" initial_value="1.63909e-14" units="dimensionless" />
1217    <variable name="C4" initial_value="6.56337e-20" units="dimensionless" />
1218    <variable name="C_Ca0" initial_value="2.72826e-3" units="dimensionless" />
1219    <variable name="C_Ca1" initial_value="6.99215e-7" units="dimensionless" />
1220    <variable name="C_Ca2" initial_value="6.71989e-11" units="dimensionless" />
1221    <variable name="C_Ca3" initial_value="2.87031e-15" units="dimensionless" />
1222    <variable name="C_Ca4" initial_value="4.59752e-20" units="dimensionless" />
1223    
1224    <!--  These variables are imported from other components. -->          
1225    <variable name="time" public_interface="in" private_interface="out" units="ms" />
1226    <variable name="V" public_interface="in" private_interface="out" units="mV" />
1227    <variable name="Ca_SS" public_interface="in" units="mM" />
1228    <variable name="Cao" public_interface="in" units="mM" />
1229    <variable name="Ko" public_interface="in" units="mM" />
1230    <variable name="Ki" public_interface="in" units="mM" />
1231    <variable name="R" public_interface="in" units="gas_constant_units" />
1232    <variable name="T" public_interface="in" units="kelvin" />
1233    <variable name="F" public_interface="in" units="faradays_constant_units" />
1234    
1235    <!-- These variables are imported from encapsulated components. -->
1236    <variable name="y" private_interface="in" units="dimensionless" />
1237    
1238    <rdf:RDF
1239      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1240      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1241      <rdf:Description rdf:about="#i_Ca_L_Ca_calculation_eq">
1242        <cmeta:comment rdf:parseType="Resource">
1243          <rdf:value>
1244            Calculation of the calcium current component of the total channel
1245            current, given as the maximal current multiplied by the
1246            voltage-dependent inactivation gate and the open probability of the
1247            channel based on the mode-switching model.
1248          </rdf:value>
1249        </cmeta:comment>
1250      </rdf:Description>
1251    </rdf:RDF>
1252    <math xmlns="http://www.w3.org/1998/Math/MathML"
1253      cmeta:id="i_Ca_L_Ca_calculation_eq">
1254      <apply id="i_Ca_L_Ca_calculation"><eq />
1255        <ci> i_Ca_L_Ca </ci>
1256        <apply><times />
1257          <ci> i_Ca_L_Ca_max </ci>
1258          <ci> y </ci>
1259          <apply><plus />
1260            <ci> O </ci>
1261            <ci> O_Ca </ci>
1262          </apply>
1263        </apply>
1264      </apply>
1265    </math>
1266      
1267    <rdf:RDF
1268      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1269      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1270      <rdf:Description rdf:about="#i_Ca_L_K_calculation_eq">
1271        <cmeta:comment rdf:parseType="Resource">
1272          <rdf:value>
1273            Calculation of the potassium current component of the total channel
1274            current.
1275          </rdf:value>
1276        </cmeta:comment>
1277      </rdf:Description>
1278    </rdf:RDF>
1279    <math xmlns="http://www.w3.org/1998/Math/MathML"
1280      cmeta:id="i_Ca_L_K_calculation_eq">
1281      <apply id="i_Ca_L_K_calculation"><eq />
1282        <ci> i_Ca_L_K </ci>
1283        <apply><times />
1284          <ci> p_k </ci>
1285          <ci> y </ci>
1286          <apply><plus />
1287            <ci> O </ci>
1288            <ci> O_Ca </ci>
1289          </apply>
1290          <apply><divide />
1291            <apply><times />
1292              <ci> V </ci>
1293              <apply><power/>
1294                <ci> F </ci>
1295                <cn cellml:units="dimensionless"> 2.0 </cn>
1296              </apply>
1297            </apply>
1298            <apply><times />
1299              <ci> R </ci>
1300              <ci> T </ci>
1301            </apply>
1302          </apply>
1303          <apply><divide />
1304            <apply><minus />
1305              <apply><times />
1306                <ci> Ki </ci>
1307                <apply><exp />
1308                  <apply><divide />
1309                    <apply><times />
1310                      <ci> V </ci>
1311                      <ci> F </ci>
1312                    </apply>
1313                    <apply><times />
1314                      <ci> R </ci>
1315                      <ci> T </ci>
1316                    </apply>
1317                  </apply>
1318                </apply>
1319              </apply>
1320              <ci> Ko </ci>
1321            </apply> 
1322            <apply><minus />
1323              <apply><exp />
1324                <apply><divide />
1325                  <apply><times />
1326                    <ci> V </ci>
1327                    <ci> F </ci>
1328                  </apply>
1329                  <apply><times />
1330                    <ci> R </ci>
1331                    <ci> T </ci>
1332                  </apply>
1333                </apply>
1334              </apply>
1335              <cn cellml:units="dimensionless"> 1.0 </cn>
1336            </apply>
1337          </apply>
1338        </apply>
1339      </apply>
1340    </math>
1341      
1342    <rdf:RDF
1343      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1344      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1345      <rdf:Description rdf:about="#p_K_calculation_eq">
1346        <cmeta:comment rdf:parseType="Resource">
1347          <rdf:value>
1348            The potassium permeability of the channel, which depends on the
1349            calcium current component.
1350          </rdf:value>
1351        </cmeta:comment>
1352      </rdf:Description>
1353    </rdf:RDF>
1354    <math xmlns="http://www.w3.org/1998/Math/MathML"
1355      cmeta:id="p_K_calculation_eq">
1356      <apply id="p_k_calculation"><eq />
1357        <ci> p_k </ci>
1358        <apply><divide />
1359          <ci> P_K </ci>
1360          <apply><plus />
1361            <cn cellml:units="dimensionless"> 1.0 </cn>
1362            <apply><divide />
1363              <ci> i_Ca_L_Ca_max </ci>
1364              <ci> i_Ca_L_Ca_half </ci>
1365            </apply>
1366          </apply>
1367        </apply>
1368      </apply>
1369    </math>
1370      
1371    <rdf:RDF
1372      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1373      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1374      <rdf:Description rdf:about="#i_Ca_L_Ca_max_calculation_eq">
1375        <cmeta:comment rdf:parseType="Resource">
1376          <rdf:value>
1377            The maximal calcium current through the channel.
1378          </rdf:value>
1379        </cmeta:comment>
1380      </rdf:Description>
1381    </rdf:RDF>
1382    <math xmlns="http://www.w3.org/1998/Math/MathML"
1383      cmeta:id="i_Ca_L_Ca_max_calculation_eq">
1384      <apply id="i_Ca_L_Ca_max_calculation"><eq />
1385        <ci> i_Ca_L_Ca_max </ci>
1386        <apply><times />
1387          <ci> P_Ca </ci>
1388          <cn cellml:units="dimensionless"> 4.0 </cn>
1389          <apply><divide />
1390            <apply><times />
1391              <ci> V </ci>
1392              <apply><power/>
1393                <ci> F </ci>
1394                <cn cellml:units="dimensionless"> 2.0 </cn>
1395              </apply>
1396            </apply>
1397            <apply><times />
1398              <ci> R </ci>
1399              <ci> T </ci>
1400            </apply>
1401          </apply>
1402          <apply><divide />
1403            <apply><minus />
1404              <apply><times />
1405                <cn cellml:units="dimensionless"> 0.001 </cn>
1406                <apply><exp />
1407                  <apply><times />
1408                    <cn cellml:units="dimensionless"> 2.0 </cn>
1409                    <ci> V </ci>
1410                    <apply><divide />
1411                      <ci> F </ci>
1412                      <apply><times />
1413                        <ci> R </ci>
1414                        <ci> T </ci>
1415                      </apply>
1416                    </apply>
1417                  </apply>
1418                </apply>
1419              </apply>
1420              <apply><times />
1421                <cn cellml:units="dimensionless"> 0.341 </cn>
1422                <ci> Cao </ci>
1423              </apply>
1424            </apply> 
1425            <apply><minus />
1426              <apply><exp />
1427                <apply><times />
1428                  <cn cellml:units="dimensionless"> 2.0 </cn>
1429                  <ci> V </ci>
1430                  <apply><divide />
1431                    <ci> F </ci>
1432                    <apply><times />
1433                      <ci> R </ci>
1434                      <ci> T </ci>
1435                    </apply>
1436                  </apply>
1437                </apply>
1438              </apply>
1439              <cn cellml:units="dimensionless"> 1.0 </cn>
1440            </apply>
1441          </apply>
1442        </apply>
1443      </apply>
1444    </math>
1445      
1446    <rdf:RDF
1447      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1448      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1449      <rdf:Description rdf:about="#alpha_calculation_eq">
1450        <cmeta:comment rdf:parseType="Resource">
1451          <rdf:value>
1452            Rate constants for state changes in mode normal.
1453          </rdf:value>
1454        </cmeta:comment>
1455      </rdf:Description>
1456    </rdf:RDF>
1457    <math xmlns="http://www.w3.org/1998/Math/MathML"
1458      cmeta:id="alpha_calculation_eq">
1459      <apply id="alpha_calculation"><eq />
1460        <ci> alpha </ci>
1461        <apply><times />
1462          <cn cellml:units="per_ms"> 0.4 </cn>
1463          <apply><exp />
1464            <apply><divide />
1465              <apply><plus />
1466                <ci> V </ci>
1467                <cn cellml:units="mV"> 12.0 </cn>
1468              </apply>
1469              <cn cellml:units="mV"> 10.0 </cn>
1470            </apply>
1471          </apply>
1472        </apply>
1473      </apply>
1474    </math>
1475    <math xmlns="http://www.w3.org/1998/Math/MathML"
1476      cmeta:id="beta_calculation_eq">
1477      <apply id="beta_calculation"><eq />
1478        <ci> beta </ci>
1479        <apply><times />
1480          <cn cellml:units="per_ms"> 0.05 </cn>
1481          <apply><exp />
1482            <apply><divide />
1483              <apply><plus />
1484                <ci> V </ci>
1485                <cn cellml:units="mV"> 12.0 </cn>
1486              </apply>
1487              <cn cellml:units="mV"> -13.0 </cn>
1488            </apply>
1489          </apply>
1490        </apply>
1491      </apply>
1492    </math>
1493      
1494    <rdf:RDF
1495      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1496      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1497      <rdf:Description rdf:about="#alpha_a_calculation_eq">
1498        <cmeta:comment rdf:parseType="Resource">
1499          <rdf:value>
1500            Rate constants for state changes in mode Ca (corresponding to
1501            alpha-prime and beta-prime in the JRW paper).
1502          </rdf:value>
1503        </cmeta:comment>
1504      </rdf:Description>
1505    </rdf:RDF>
1506    <math xmlns="http://www.w3.org/1998/Math/MathML"
1507      cmeta:id="alpha_a_calculation_eq">
1508      <apply id="alpha_a_calculation"><eq />
1509        <ci> alpha_a </ci>
1510        <apply><times />
1511          <ci> alpha </ci>
1512          <ci> a </ci>
1513        </apply>
1514      </apply>
1515    </math>
1516    <math xmlns="http://www.w3.org/1998/Math/MathML"
1517      cmeta:id="beta_a_calculation_eq">
1518      <apply id="beta_b_calculation"><eq />
1519        <ci> beta_b </ci>
1520        <apply><divide />
1521          <ci> beta </ci>
1522          <ci> b </ci>
1523        </apply>
1524      </apply>
1525    </math>
1526      
1527    <rdf:RDF
1528      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1529      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1530      <rdf:Description rdf:about="#gamma_calculation_eq">
1531        <cmeta:comment rdf:parseType="Resource">
1532          <rdf:value>
1533            Rate constant for switching between mode normal and mode Ca.
1534          </rdf:value>
1535        </cmeta:comment>
1536      </rdf:Description>
1537    </rdf:RDF>
1538    <math xmlns="http://www.w3.org/1998/Math/MathML"
1539      cmeta:id="gamma_calculation_eq">
1540      <apply id="gamma_calculation"><eq />
1541        <ci> gamma </ci>
1542        <apply><times />
1543          <cn cellml:units="dimensionless"> 0.1875 </cn>
1544          <ci> Ca_SS </ci>
1545        </apply>
1546      </apply>
1547    </math>
1548      
1549    <rdf:RDF
1550      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1551      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1552      <rdf:Description rdf:about="#C0_diff_eq">
1553        <cmeta:comment rdf:parseType="Resource">
1554          <rdf:value>
1555            The kinetics of the state transitions in mode normal.
1556            In the normal mode, the calcium channel is able to make the
1557            transition to the open, conducting state (O) from the closed state
1558            (C) at a normal rate.
1559          </rdf:value>
1560        </cmeta:comment>
1561      </rdf:Description>
1562    </rdf:RDF>
1563    <math xmlns="http://www.w3.org/1998/Math/MathML"
1564      cmeta:id="C0_diff_eq">
1565      <apply id="C0_diff_eq"><eq />
1566        <apply><diff />
1567          <bvar><ci> time </ci></bvar>
1568          <ci> C0 </ci>
1569        </apply>
1570        <apply><minus />
1571          <apply><plus />
1572            <apply><times />
1573              <ci> beta </ci>
1574              <ci> C1 </ci>
1575            </apply>
1576            <apply><times />
1577              <ci> omega </ci>
1578              <ci> C_Ca0 </ci>
1579            </apply>
1580          </apply>
1581          <apply><times />
1582            <apply><plus />
1583              <apply><times />
1584                <cn cellml:units="dimensionless"> 4.0 </cn>
1585                <ci> alpha </ci>
1586              </apply>
1587              <ci> gamma </ci>
1588            </apply>
1589            <ci> C0 </ci>
1590          </apply>
1591        </apply>
1592      </apply>
1593    </math>
1594    <math xmlns="http://www.w3.org/1998/Math/MathML"
1595      cmeta:id="C1_diff_eq">
1596      <apply id="C1_diff_eq"><eq />
1597        <apply><diff />
1598          <bvar><ci> time </ci></bvar>
1599          <ci> C1 </ci>
1600        </apply>
1601        <apply><minus />
1602          <apply><plus />
1603            <apply><times />
1604              <cn cellml:units="dimensionless"> 4.0 </cn>
1605              <ci> alpha </ci>
1606              <ci> C0 </ci>
1607            </apply>
1608            <apply><times />
1609              <cn cellml:units="dimensionless"> 2.0 </cn>
1610              <ci> beta </ci>
1611              <ci> C2 </ci>
1612            </apply>
1613            <apply><times />
1614              <apply><divide />
1615                <ci> omega </ci>
1616                <ci> b </ci>
1617              </apply>
1618              <ci> C_Ca1 </ci>
1619            </apply>
1620          </apply>
1621          <apply><times />
1622            <apply><plus />
1623              <ci> beta </ci>
1624              <apply><times />
1625                <cn cellml:units="dimensionless"> 3.0 </cn>
1626                <ci> alpha </ci>
1627              </apply>
1628              <apply><times />
1629                <ci> gamma </ci>
1630                <ci> a </ci>
1631              </apply>
1632            </apply>
1633            <ci> C1 </ci>
1634          </apply>
1635        </apply>
1636      </apply>
1637    </math>
1638    <math xmlns="http://www.w3.org/1998/Math/MathML"
1639      cmeta:id="C2_diff_eq">
1640      <apply id="C2_diff_eq"><eq />
1641        <apply><diff />
1642          <bvar><ci> time </ci></bvar>
1643          <ci> C2 </ci>
1644        </apply>
1645        <apply><minus />
1646          <apply><plus />
1647            <apply><times />
1648              <cn cellml:units="dimensionless"> 3.0 </cn>
1649              <ci> alpha </ci>
1650              <ci> C1 </ci>
1651            </apply>
1652            <apply><times />
1653              <cn cellml:units="dimensionless"> 3.0 </cn>
1654              <ci> beta </ci>
1655              <ci> C3 </ci>
1656            </apply>
1657            <apply><times />
1658              <apply><divide />
1659                <ci> omega </ci>
1660                <apply><power />
1661                  <ci> b </ci>
1662                  <cn cellml:units="dimensionless"> 2.0 </cn>
1663                </apply>
1664              </apply>
1665              <ci> C_Ca2 </ci>
1666            </apply>
1667          </apply>
1668          <apply><times />
1669            <apply><plus />
1670              <apply><times />
1671                <ci> beta </ci>
1672                <cn cellml:units="dimensionless"> 2.0 </cn>
1673              </apply>
1674              <apply><times />
1675                <cn cellml:units="dimensionless"> 2.0 </cn>
1676                <ci> alpha </ci>
1677              </apply>
1678              <apply><times />
1679                <ci> gamma </ci>
1680                <apply><power />
1681                  <ci> a </ci>
1682                  <cn cellml:units="dimensionless"> 2.0 </cn>
1683                </apply>
1684              </apply>
1685            </apply>
1686            <ci> C2 </ci>
1687          </apply>
1688        </apply>
1689      </apply> 
1690    </math>
1691    <math xmlns="http://www.w3.org/1998/Math/MathML"
1692      cmeta:id="C3_diff_eq">
1693      <apply id="C3_diff_eq"><eq />
1694        <apply><diff />
1695          <bvar><ci> time </ci></bvar>
1696          <ci> C3 </ci>
1697        </apply>
1698        <apply><minus />
1699          <apply><plus />
1700            <apply><times />
1701              <cn cellml:units="dimensionless"> 2.0 </cn>
1702              <ci> alpha </ci>
1703              <ci> C2 </ci>
1704            </apply>
1705            <apply><times />
1706              <cn cellml:units="dimensionless"> 4.0 </cn>
1707              <ci> beta </ci>
1708              <ci> C4 </ci>
1709            </apply>
1710            <apply><times />
1711              <apply><divide />
1712                <ci> omega </ci>
1713                <apply><power />
1714                  <ci> b </ci>
1715                  <cn cellml:units="dimensionless"> 3.0 </cn>
1716                </apply>
1717              </apply>
1718              <ci> C_Ca3 </ci>
1719            </apply>
1720          </apply>
1721          <apply><times />
1722            <apply><plus />
1723              <apply><times />
1724                <ci> beta </ci>
1725                <cn cellml:units="dimensionless"> 3.0 </cn>
1726              </apply>
1727              <ci> alpha </ci>
1728              <apply><times />
1729                <ci> gamma </ci>
1730                <apply><power />
1731                  <ci> a </ci>
1732                  <cn cellml:units="dimensionless"> 3.0 </cn>
1733                </apply>
1734              </apply>
1735            </apply>
1736            <ci> C3 </ci>
1737          </apply>
1738        </apply>
1739      </apply> 
1740    </math>
1741    <math xmlns="http://www.w3.org/1998/Math/MathML"
1742      cmeta:id="C4_diff_eq">
1743      <apply id="C4_diff_eq"><eq />
1744        <apply><diff />
1745          <bvar><ci> time </ci></bvar>
1746          <ci> C4 </ci>
1747        </apply>
1748        <apply><minus />
1749          <apply><plus />
1750            <apply><times />
1751              <ci> alpha </ci>
1752              <ci> C3 </ci>
1753            </apply>
1754            <apply><times />
1755              <ci> g </ci>
1756              <ci> O </ci>
1757            </apply>
1758            <apply><times />
1759              <apply><divide />
1760                <ci> omega </ci>
1761                <apply><power />
1762                  <ci> b </ci>
1763                  <cn cellml:units="dimensionless"> 4.0 </cn>
1764                </apply>
1765              </apply>
1766              <ci> C_Ca4 </ci>
1767            </apply>
1768          </apply>
1769          <apply><times />
1770            <apply><plus />
1771              <apply><times />
1772                <ci> beta </ci>
1773                <cn cellml:units="dimensionless"> 4.0 </cn>
1774              </apply>
1775              <ci> f </ci>
1776              <apply><times />
1777                <ci> gamma </ci>
1778                <apply><power />
1779                  <ci> a </ci>
1780                  <cn cellml:units="dimensionless"> 4.0 </cn>
1781                </apply>
1782              </apply>
1783            </apply>
1784            <ci> C4 </ci>
1785          </apply>
1786        </apply>
1787      </apply>
1788    </math>
1789    <math xmlns="http://www.w3.org/1998/Math/MathML"
1790      cmeta:id="O_diff_eq">
1791      <apply id="O_diff_eq"><eq />
1792        <apply><diff />
1793          <bvar><ci> time </ci></bvar>
1794          <ci> O </ci>
1795        </apply>
1796        <apply><minus />
1797          <apply><times />
1798            <ci> f </ci>
1799            <ci> C4 </ci>
1800          </apply>
1801          <apply><times />
1802            <ci> g </ci>
1803            <ci> O </ci>
1804          </apply>
1805        </apply>
1806      </apply>
1807    </math>
1808      
1809    <rdf:RDF
1810      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
1811      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
1812      <rdf:Description rdf:about="#C_Ca0_diff_eq">
1813        <cmeta:comment rdf:parseType="Resource">
1814          <rdf:value>
1815            The kinetics of the state transitions in mode Ca.
1816            Calcium binding to the Ca channel induces a conformational change
1817            from normal mode to mode Ca. This effectively inhibits the
1818            conduction of calcium ions because in mode Ca, the calcium channel
1819            makes the transition to the open, conducting state (O) extremely
1820            slowly.
1821          </rdf:value>
1822        </cmeta:comment>
1823      </rdf:Description>
1824    </rdf:RDF>
1825    <math xmlns="http://www.w3.org/1998/Math/MathML"
1826      cmeta:id="C_Ca0_diff_eq">
1827      <apply id="C_Ca0_diff_eq"><eq />
1828        <apply><diff />
1829          <bvar><ci> time </ci></bvar>
1830          <ci> C_Ca0 </ci>
1831        </apply>
1832        <apply><minus />
1833          <apply><plus />
1834            <apply><times />
1835              <ci> beta_b </ci>
1836              <ci> C_Ca1 </ci>
1837            </apply>
1838            <apply><times />
1839              <ci> gamma </ci>
1840              <ci> C_Ca0 </ci>
1841            </apply>
1842          </apply>
1843          <apply><times />
1844            <apply><plus />
1845              <apply><times />
1846                <cn cellml:units="dimensionless"> 4.0 </cn>
1847                <ci> alpha_a </ci>
1848              </apply>
1849              <ci> omega </ci>
1850            </apply>
1851            <ci> C_Ca0 </ci>
1852          </apply>
1853        </apply>
1854      </apply>
1855    </math>
1856    <math xmlns="http://www.w3.org/1998/Math/MathML"
1857      cmeta:id="C_Ca1_diff_eq">
1858      <apply id="C_Ca1_diff_eq"><eq />
1859        <apply><diff />
1860          <bvar><ci> time </ci></bvar>
1861          <ci> C_Ca1 </ci>
1862        </apply>
1863        <apply><minus />
1864          <apply><plus />
1865            <apply><times />
1866              <cn cellml:units="dimensionless"> 4.0 </cn>
1867              <ci> alpha_a </ci>
1868              <ci> C_Ca0 </ci>
1869            </apply>
1870            <apply><times />
1871              <cn cellml:units="dimensionless"> 2.0 </cn>
1872              <ci> beta_b </ci>
1873              <ci> C_Ca2 </ci>
1874            </apply>
1875            <apply><times />
1876              <ci> gamma </ci>
1877              <ci> a </ci>
1878              <ci> C1 </ci>
1879            </apply>
1880          </apply>
1881          <apply><times />
1882            <apply><plus />
1883              <ci> beta_b </ci>
1884              <apply><times />
1885                <cn cellml:units="dimensionless"> 3.0 </cn>
1886                <ci> alpha_a </ci>
1887              </apply>
1888              <apply><divide />
1889                <ci> omega </ci>
1890                <ci> b </ci>
1891              </apply>
1892            </apply>
1893            <ci> C_Ca1 </ci>
1894          </apply>
1895        </apply>
1896      </apply>
1897    </math>
1898    <math xmlns="http://www.w3.org/1998/Math/MathML"
1899      cmeta:id="C_Ca2_diff_eq">
1900      <apply id="C_Ca2_diff_eq"><eq />
1901        <apply><diff />
1902          <bvar><ci> time </ci></bvar>
1903          <ci> C_Ca2 </ci>
1904        </apply>
1905        <apply><minus />
1906          <apply><plus />
1907            <apply><times />
1908              <cn cellml:units="dimensionless"> 3.0 </cn>
1909              <ci> alpha_a </ci>
1910              <ci> C_Ca1 </ci>
1911            </apply>
1912            <apply><times />
1913              <cn cellml:units="dimensionless"> 3.0 </cn>
1914              <ci> beta_b </ci>
1915              <ci> C_Ca3 </ci>
1916            </apply>
1917            <apply><times />
1918              <ci> gamma </ci>
1919              <apply><power />
1920                <ci> a </ci>
1921                <cn cellml:units="dimensionless"> 2.0 </cn> 
1922              </apply>
1923              <ci> C2 </ci>
1924            </apply>
1925          </apply>
1926          <apply><times />
1927            <apply><plus />
1928              <apply><times />
1929                <ci> beta_b </ci>
1930                <cn cellml:units="dimensionless"> 2.0 </cn>
1931              </apply>
1932              <apply><times />
1933                <cn cellml:units="dimensionless"> 2.0 </cn>
1934                <ci> alpha_a </ci>
1935              </apply>
1936              <apply><divide />
1937                <ci> omega </ci>
1938                <apply><power />
1939                  <ci> b </ci>
1940                  <cn cellml:units="dimensionless"> 2.0 </cn>
1941                </apply>
1942              </apply>
1943            </apply>
1944            <ci> C_Ca2 </ci>
1945          </apply>
1946        </apply>
1947      </apply>
1948    </math>
1949    <math xmlns="http://www.w3.org/1998/Math/MathML"
1950      cmeta:id="C_Ca3_diff_eq">
1951      <apply id="C_Ca3_diff_eq"><eq />
1952        <apply><diff />
1953          <bvar><ci> time </ci></bvar>
1954          <ci> C_Ca3 </ci>
1955        </apply>
1956        <apply><minus />
1957          <apply><plus />
1958            <apply><times />
1959              <cn cellml:units="dimensionless"> 2.0 </cn>
1960              <ci> alpha_a </ci>
1961              <ci> C_Ca2 </ci>
1962            </apply>
1963            <apply><times />
1964              <cn cellml:units="dimensionless"> 4.0 </cn>
1965              <ci> beta_b </ci>
1966              <ci> C_Ca4 </ci>
1967            </apply>
1968            <apply><times />
1969              <ci> gamma </ci>
1970              <apply><power />
1971                <ci> a </ci>
1972                <cn cellml:units="dimensionless"> 3.0 </cn>
1973              </apply> 
1974              <ci> C3 </ci>
1975            </apply>
1976          </apply>
1977          <apply><times />
1978            <apply><plus />
1979              <apply><times />
1980                <ci> beta_b </ci>
1981                <cn cellml:units="dimensionless"> 3.0 </cn>
1982              </apply>
1983              <ci> alpha_a </ci>
1984              <apply><divide />
1985                <ci> omega </ci>
1986                <apply><power />
1987                  <ci> b </ci>
1988                  <cn cellml:units="dimensionless"> 3.0 </cn>
1989                </apply>
1990              </apply>
1991            </apply>
1992            <ci> C_Ca3 </ci>
1993          </apply>
1994        </apply>
1995      </apply>
1996    </math>
1997    <math xmlns="http://www.w3.org/1998/Math/MathML"
1998      cmeta:id="C_Ca4_diff_eq">
1999      <apply id="C_Ca4_diff_eq"><eq />
2000        <apply><diff />
2001          <bvar><ci> time </ci></bvar>
2002          <ci> C_Ca4 </ci>
2003        </apply>
2004        <apply><minus />
2005          <apply><plus />
2006            <apply><times />
2007              <ci> alpha_a </ci>
2008              <ci> C_Ca3 </ci>
2009            </apply>
2010            <apply><times />
2011              <ci> g_ </ci>
2012              <ci> O_Ca </ci>
2013            </apply>
2014            <apply><times />
2015              <ci> gamma </ci>
2016              <apply><power />
2017                <ci> a </ci>
2018                <cn cellml:units="dimensionless"> 4.0 </cn>
2019              </apply> 
2020              <ci> C4 </ci>
2021            </apply>
2022          </apply>
2023          <apply><times />
2024            <apply><plus />
2025              <apply><times />
2026                <ci> beta_b </ci>
2027                <cn cellml:units="dimensionless"> 4.0 </cn>
2028              </apply>
2029              <ci> f_ </ci>
2030              <apply><divide />
2031                <ci> omega </ci>
2032                <apply><power />
2033                  <ci> b </ci>
2034                  <cn cellml:units="dimensionless"> 4.0 </cn>
2035                </apply>
2036              </apply>
2037            </apply>
2038            <ci> C_Ca4 </ci>
2039          </apply>
2040        </apply>
2041      </apply>
2042    </math>
2043    <math xmlns="http://www.w3.org/1998/Math/MathML"
2044      cmeta:id="O_Ca_diff_eq">
2045      <apply id="O_Ca_diff_eq"><eq />
2046        <apply><diff />
2047          <bvar><ci> time </ci></bvar>
2048          <ci> O_Ca </ci>
2049        </apply>
2050        <apply><minus />
2051          <apply><times />
2052            <ci> f_ </ci>
2053            <ci> C_Ca4 </ci>
2054          </apply>
2055          <apply><times />
2056            <ci> g_ </ci>
2057            <ci> O_Ca </ci>
2058          </apply>
2059        </apply>
2060      </apply>
2061    </math>
2062  </component>
2063  
2064  <!-- 
2065    The "L_type_Ca_channel" component has an encapsulated voltage inactivation  
2066    gate, y.
2067  -->
2068  <component name="L_type_Ca_channel_y_gate"
2069    cmeta:id="L_type_Ca_channel_y_gate">
2070    <rdf:RDF
2071      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2072      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2073      <rdf:Description rdf:about="#L_type_Ca_channel_y_gate">
2074        <cmeta:comment rdf:parseType="Resource">
2075          <rdf:value>
2076            The voltage-dependent inactivation gate for the L-type calcium
2077            channel - the y gate.
2078          </rdf:value>
2079        </cmeta:comment>
2080      </rdf:Description>
2081    </rdf:RDF>
2082
2083    <!-- this variable is defined here and used in other components. -->
2084    <variable
2085        name="y" public_interface="out"
2086        initial_value="0.998983" units="dimensionless" />
2087    
2088    <!-- These variables are defined here and only used internally. -->         
2089    <variable name="y_infinity" units="dimensionless" />
2090    <variable name="tau_y" units="dimensionless" />
2091    
2092    <!-- 
2093      These variables are imported from the environment and the membrane via    
2094      the "L_type_Ca_channel" component.
2095    -->
2096    <variable name="V" public_interface="in" units="mV" />
2097    <variable name="time" public_interface="in" units="ms" />
2098    
2099    <rdf:RDF
2100      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2101      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2102      <rdf:Description rdf:about="#y_diff_eq">
2103        <cmeta:comment rdf:parseType="Resource">
2104          <rdf:value>
2105            The kinetics of the y gate.
2106          </rdf:value>
2107        </cmeta:comment>
2108      </rdf:Description>
2109    </rdf:RDF>
2110    <math xmlns="http://www.w3.org/1998/Math/MathML" cmeta:id="y_diff_eq">
2111      <apply id="y_diff_eq"><eq />
2112        <apply><diff />
2113          <bvar><ci> time </ci></bvar>
2114          <ci> y </ci>
2115        </apply>
2116        <apply><divide />
2117          <apply><minus />
2118            <ci> y_infinity </ci>
2119            <ci> y </ci>
2120          </apply>
2121          <ci> tau_y </ci>
2122        </apply>
2123      </apply>
2124    </math>
2125    <math xmlns="http://www.w3.org/1998/Math/MathML"
2126      cmeta:id="y_infinity_calculation_eq">
2127      <apply id="y_infinity_calculation"><eq />
2128        <ci> y_infinity </ci>
2129        <apply><plus />
2130          <apply><divide />
2131            <cn cellml:units="dimensionless"> 1.0 </cn>
2132            <apply><plus />
2133              <cn cellml:units="dimensionless"> 1.0 </cn>
2134              <apply><exp />
2135                <apply><divide />
2136                  <apply><plus />
2137                    <ci> V </ci>
2138                    <cn cellml:units="mV"> 55.0 </cn>
2139                  </apply>
2140                  <cn cellml:units="mV"> 7.5 </cn>
2141                </apply>
2142              </apply>
2143            </apply>
2144          </apply>
2145          <apply><divide />
2146            <cn cellml:units="dimensionless"> 0.1 </cn>
2147            <apply><plus />
2148              <cn cellml:units="dimensionless"> 1.0 </cn>
2149              <apply><exp />
2150                <apply><divide />
2151                  <apply><plus />
2152                    <apply><minus />
2153                      <ci> V </ci>
2154                    </apply>
2155                    <cn cellml:units="mV"> 21.0 </cn>
2156                  </apply>
2157                  <cn cellml:units="mV"> 6.0 </cn>
2158                </apply>
2159              </apply>
2160            </apply>
2161          </apply>
2162        </apply>
2163      </apply>
2164    </math>
2165    <math xmlns="http://www.w3.org/1998/Math/MathML"
2166      cmeta:id="tau_y_calculation_eq">
2167      <apply id="tau_y_calculation"><eq />
2168        <ci> tau_y </ci>
2169        <apply><plus />
2170          <cn cellml:units="dimensionless"> 20.0 </cn>
2171          <apply><divide />
2172            <cn cellml:units="dimensionless"> 600.0 </cn>
2173            <apply><plus />
2174              <cn cellml:units="dimensionless"> 1.0 </cn>
2175              <apply><exp />
2176                <apply><divide />
2177                  <apply><plus />
2178                    <ci> V </ci>
2179                    <cn cellml:units="mV"> 30.0 </cn>
2180                  </apply>
2181                  <cn cellml:units="mV"> 9.5 </cn>
2182                </apply>
2183              </apply>
2184            </apply>
2185          </apply>
2186        </apply>
2187      </apply>
2188    </math>
2189  </component>
2190  
2191  <!--
2192    The time-dependent potassium current has an X^2 dependence on it's          
2193    activation gate, and an Xi inactivation gate.  These are encapsulated in the
2194    parent "time_dependent_potassium_current" component.
2195  -->
2196  <component name="time_dependent_potassium_current"
2197    cmeta:id="time_dependent_potassium_current">
2198    <rdf:RDF
2199      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2200      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2201      <rdf:Description rdf:about="#time_dependent_potassium_current">
2202        <cmeta:comment rdf:parseType="Resource">
2203          <rdf:value>
2204            The time-dependent potassium current has an X^2 dependence on it's
2205            activation gate, and an Xi inactivation gate. This channel is also
2206            assumed permeable to sodium ions.
2207          </rdf:value>
2208        </cmeta:comment>
2209      </rdf:Description>
2210    </rdf:RDF>
2211
2212    <!-- This variable is defined here and used in other components. -->
2213    <variable name="i_K" public_interface="out" units="uA_per_mm2" />
2214    
2215    <!-- These variables are defined here and only used internally. -->
2216    <variable name="g_K" units="mS_per_mm2" />
2217    <variable name="g_K_max" initial_value="0.001128" units="mS_per_mm2" />
2218    <variable name="E_K" units="mV" />
2219    <variable name="P_NaK" initial_value="0.01833" units="dimensionless" />
2220    
2221    <!-- These variables are imported from other components. -->
2222    <variable
2223        name="time" public_interface="in"
2224        private_interface="out" units="ms" />
2225    <variable
2226        name="V" public_interface="in"
2227        private_interface="out" units="mV" />
2228    <variable name="Ko" public_interface="in" units="mM" />
2229    <variable name="Ki" public_interface="in" units="mM" />
2230    <variable name="Nao" public_interface="in" units="mM" />
2231    <variable name="Nai" public_interface="in" units="mM" />
2232    <variable name="R" public_interface="in" units="gas_constant_units" />
2233    <variable name="T" public_interface="in" units="kelvin" />
2234    <variable name="F" public_interface="in" units="faradays_constant_units" />
2235    
2236    <!-- These variables are imported from encapsulated components. -->
2237    <variable name="X" private_interface="in" units="dimensionless" />
2238    <variable name="Xi" private_interface="in" units="dimensionless" />
2239    
2240    <rdf:RDF
2241      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2242      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2243      <rdf:Description rdf:about="#g_K_calculation_eq">
2244        <cmeta:comment rdf:parseType="Resource">
2245          <rdf:value>
2246            Calculation of the maximal channel conductance, dependent on
2247            extracellular potassium concentration.
2248          </rdf:value>
2249        </cmeta:comment>
2250      </rdf:Description>
2251    </rdf:RDF>
2252    <math xmlns="http://www.w3.org/1998/Math/MathML"
2253      cmeta:id="g_K_calculation_eq">
2254      <apply id="g_K_calculation"><eq />
2255        <ci> g_K </ci>
2256        <apply><times />
2257          <ci>g_K_max</ci>
2258          <apply><root />
2259            <apply><divide />
2260              <ci> Ko </ci>
2261              <cn cellml:units="mM"> 5.4 </cn>
2262            </apply>
2263          </apply>                                                              
2264        </apply>
2265      </apply>
2266    </math>
2267      
2268    <rdf:RDF
2269      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2270      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2271      <rdf:Description rdf:about="#E_K_calculation_eq">
2272        <cmeta:comment rdf:parseType="Resource">
2273          <rdf:value>
2274            The reversal potential of the channel.
2275          </rdf:value>
2276        </cmeta:comment>
2277      </rdf:Description>
2278    </rdf:RDF>
2279    <math xmlns="http://www.w3.org/1998/Math/MathML"
2280      cmeta:id="E_K_calculation_eq">
2281      <apply id="E_K_calculation"><eq />
2282        <ci> E_K </ci>
2283        <apply><times />
2284          <apply><divide />
2285            <apply><times />
2286              <ci> R </ci>
2287              <ci> T </ci>
2288            </apply>
2289            <ci> F </ci>
2290          </apply>
2291          <apply><ln />
2292            <apply><divide />
2293              <apply><plus />
2294                <ci> Ko </ci>
2295                <apply><times />
2296                  <ci> P_NaK </ci>
2297                  <ci> Nao </ci>
2298                </apply>
2299              </apply>
2300              <apply><plus />
2301                <ci> Ki </ci>
2302                <apply><times />
2303                  <ci> P_NaK </ci>
2304                  <ci> Nai </ci>
2305                </apply>
2306              </apply>
2307            </apply>
2308          </apply>
2309        </apply>
2310      </apply>
2311    </math>
2312      
2313    <rdf:RDF
2314      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2315      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2316      <rdf:Description rdf:about="#i_K_calculation_eq">
2317        <cmeta:comment rdf:parseType="Resource">
2318          <rdf:value>
2319            Calculation of the time-dependent potassium current.
2320          </rdf:value>
2321        </cmeta:comment>
2322      </rdf:Description>
2323    </rdf:RDF>
2324    <math xmlns="http://www.w3.org/1998/Math/MathML"
2325      cmeta:id="i_K_calculation_eq">
2326      <apply id="i_K_calculation"><eq />
2327        <ci> i_K </ci>
2328        <apply><times />
2329          <ci> g_K </ci>
2330          <ci> Xi </ci>
2331          <apply><power />
2332            <ci> X </ci>
2333            <cn cellml:units="dimensionless"> 2.0 </cn>
2334          </apply>
2335          <apply><minus />
2336            <ci> V </ci>
2337            <ci> E_K </ci>
2338          </apply>
2339        </apply>
2340      </apply>
2341    </math>
2342  </component>
2343  
2344  <!--  
2345    The "time_dependent_potassium_current_X_gate" component is the              
2346    time-dependent activation gate encapsulated in the rapid_time-dependent     
2347    potassium current.  
2348  -->
2349  <component name="time_dependent_potassium_current_X_gate"
2350    cmeta:id="time_dependent_potassium_current_X_gate">
2351    <rdf:RDF
2352      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2353      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2354      <rdf:Description rdf:about="#time_dependent_potassium_current_X_gate">
2355        <cmeta:comment rdf:parseType="Resource">
2356          <rdf:value>
2357            The voltage- and time-dependent activation gate for the
2358            time-dependent potassium current - the X gate.
2359          </rdf:value>
2360        </cmeta:comment>
2361      </rdf:Description>
2362    </rdf:RDF>
2363
2364    <!-- This variable is defined here and used in other components. -->
2365    <variable
2366        name="X" public_interface="out"
2367        initial_value="0.000928836" units="dimensionless" />
2368    
2369    <!-- These variables are defined here and only used internally. -->
2370    <variable name="alpha_X" units="per_ms" />
2371    <variable name="beta_X" units="per_ms" />
2372    
2373    <!-- 
2374      These variables are imported from the environment and the membrane via    
2375      the "time_dependent_potassium_current" component. -->
2376    <variable name="V" public_interface="in" units="mV" />
2377    <variable name="time" public_interface="in" units="ms" />
2378    
2379    <rdf:RDF
2380      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2381      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2382      <rdf:Description rdf:about="#alpha_X_calculation_eq">
2383        <cmeta:comment rdf:parseType="Resource">
2384          <rdf:value>
2385            The opening rate of the X gate.
2386          </rdf:value>
2387        </cmeta:comment>
2388      </rdf:Description>
2389    </rdf:RDF>
2390    <math xmlns="http://www.w3.org/1998/Math/MathML"
2391      cmeta:id="alpha_X_calculation_eq">
2392      <apply id="alpha_X_calculation"><eq />
2393        <ci> alpha_X </ci>
2394        <apply><times />
2395          <cn cellml:units="per_mV_ms"> 0.0000719 </cn>
2396          <apply><divide />
2397            <apply><plus />
2398              <ci> V </ci>
2399              <cn cellml:units="mV"> 30.0 </cn>
2400            </apply>
2401            <apply><minus />
2402              <cn cellml:units="dimensionless"> 1.0 </cn>
2403              <apply><exp />
2404                <apply><times />
2405                  <cn cellml:units="per_mV"> -0.148 </cn>
2406                  <apply><plus />
2407                    <ci> V </ci>
2408                    <cn cellml:units="mV"> 30.0 </cn>
2409                  </apply>
2410                </apply>
2411              </apply>
2412            </apply>
2413          </apply>
2414        </apply>
2415      </apply>
2416    </math>
2417      
2418    <rdf:RDF
2419      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2420      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2421      <rdf:Description rdf:about="#beta_X_calculation_eq">
2422        <cmeta:comment rdf:parseType="Resource">
2423          <rdf:value>
2424            The closing rate of the X gate.
2425          </rdf:value>
2426        </cmeta:comment>
2427      </rdf:Description>
2428    </rdf:RDF>
2429    <math xmlns="http://www.w3.org/1998/Math/MathML"
2430      cmeta:id="beta_X_calculation_eq">
2431      <apply id="beta_X_calculation"><eq />
2432        <ci> beta_X </ci>
2433        <apply><times />
2434          <cn cellml:units="per_mV_ms"> 0.000131 </cn>
2435          <apply><divide />
2436            <apply><plus />
2437              <ci> V </ci>
2438              <cn cellml:units="mV"> 30.0 </cn>
2439            </apply>
2440            <apply><plus />
2441              <cn cellml:units="dimensionless"> -1.0 </cn>
2442              <apply><exp />
2443                <apply><times />
2444                  <cn cellml:units="per_mV"> 0.0687 </cn>
2445                  <apply><plus />
2446                    <ci> V </ci>
2447                    <cn cellml:units="mV"> 30.0 </cn>
2448                  </apply>
2449                </apply>
2450              </apply>
2451            </apply>
2452          </apply>
2453        </apply>
2454      </apply>
2455    </math>
2456      
2457    <rdf:RDF
2458      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2459      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2460      <rdf:Description rdf:about="#dX_dt_eq">
2461        <cmeta:comment rdf:parseType="Resource">
2462          <rdf:value>
2463            The kinetics of the X gate.
2464          </rdf:value>
2465        </cmeta:comment>
2466      </rdf:Description>
2467    </rdf:RDF>
2468    <math xmlns="http://www.w3.org/1998/Math/MathML"
2469      cmeta:id="dX_dt_eq">
2470      <apply id="dX_dt"><eq />
2471        <apply><diff />
2472          <bvar><ci> time </ci></bvar>
2473          <ci> X </ci>
2474        </apply>
2475        <apply><minus />
2476          <apply><times />
2477            <ci> alpha_X </ci>
2478            <apply><minus />
2479              <cn cellml:units="dimensionless"> 1.0 </cn>
2480              <ci> X </ci>
2481            </apply>
2482          </apply>
2483          <apply><times />
2484            <ci> beta_X </ci>
2485            <ci> X </ci>
2486          </apply>
2487        </apply>
2488      </apply>
2489    </math>
2490  </component>
2491      
2492  <!--  
2493    The "time_dependent_potassium_current_Xi_gate" component is the             
2494    time-independent inactivation gate encapsulated in the time-dependent       
2495    potassium current.  
2496  -->
2497  <component name="time_dependent_potassium_current_Xi_gate"
2498    cmeta:id="time_dependent_potassium_current_Xi_gate">
2499    <rdf:RDF
2500      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2501      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2502      <rdf:Description rdf:about="#time_dependent_potassium_current_Xi_gate">
2503        <cmeta:comment rdf:parseType="Resource">
2504          <rdf:value>
2505            The time-independent inactivation gate for the time-dependent
2506            potassium channel.
2507          </rdf:value>
2508        </cmeta:comment>
2509      </rdf:Description>
2510    </rdf:RDF>
2511
2512    <!-- This variable is defined here and used in other components. -->
2513    <variable name="Xi" public_interface="out" units="dimensionless" />
2514
2515    <!-- 
2516      These variables are imported from the "environment" and the "membrane" via
2517      the "time_dependent_potassium_current" component.
2518    -->
2519    <variable name="V" public_interface="in" units="mV" />
2520    <variable name="time" public_interface="in" units="ms" />
2521    
2522    <rdf:RDF
2523      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2524      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2525      <rdf:Description rdf:about="#Xi_calculation_eq">
2526        <cmeta:comment rdf:parseType="Resource">
2527          <rdf:value>
2528            Xi is the inward rectification parameter and is given by the
2529            following equation.
2530          </rdf:value>
2531        </cmeta:comment>
2532      </rdf:Description>
2533    </rdf:RDF>
2534    <math xmlns="http://www.w3.org/1998/Math/MathML"
2535      cmeta:id="Xi_calculation_eq">
2536      <apply id="Xi_calculation"><eq />
2537        <ci> Xi </ci>
2538        <apply><divide />
2539          <cn cellml:units="dimensionless"> 1.0 </cn>
2540          <apply><plus />
2541            <cn cellml:units="dimensionless"> 1.0 </cn>
2542            <apply><exp />
2543              <apply><divide />
2544                <apply><minus />
2545                  <ci> V </ci>
2546                  <cn cellml:units="mV"> 56.26 </cn>
2547                </apply>
2548                <cn cellml:units="mV"> 32.1 </cn>
2549              </apply>
2550            </apply>
2551          </apply>
2552        </apply>
2553      </apply>
2554    </math>
2555  </component>
2556  
2557  
2558  <!--  
2559    The "time_independent_potassium_current" component contains a single        
2560    inactivation gate (K1) whose time constant is small enough that it          
2561    can be approximated by its steady-state value K1_infinity.  
2562  -->
2563  <component name="time_independent_potassium_current"
2564    cmeta:id="time_independent_potassium_current">
2565    <rdf:RDF
2566      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2567      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2568      <rdf:Description rdf:about="#time_independent_potassium_current">
2569        <cmeta:comment rdf:parseType="Resource">
2570          <rdf:value>
2571            The time-independent potassium current.
2572          </rdf:value>
2573        </cmeta:comment>
2574      </rdf:Description>
2575    </rdf:RDF>
2576
2577    <!-- These variables are defined here and used in other components. -->
2578    <variable name="i_K1" public_interface="out" units="uA_per_mm2" />
2579    <variable
2580        name="E_K1" public_interface="out"
2581        private_interface="out" units="mV" />
2582    
2583    <!-- This variable is defined here and only used internally. -->
2584    <variable name="g_K1" units="mS_per_mm2" />
2585    <variable name="g_K1_max" initial_value="7.5e-3" units="mS_per_mm2" />
2586    
2587    <!-- 
2588      These variables are imported from other components.  They are all used in 
2589      the parent "time_independent_potassium_current" component and some are    
2590      also passed via this interface to the encapsulated gates.  
2591    -->
2592    <variable
2593        name="time" public_interface="in"
2594        private_interface="out" units="ms" />
2595    <variable
2596        name="V" public_interface="in"
2597        private_interface="out" units="mV" />
2598    <variable name="Ko" public_interface="in" units="mM" />
2599    <variable name="Ki" public_interface="in" units="mM" />
2600    <variable name="R" public_interface="in" units="gas_constant_units" />
2601    <variable name="T" public_interface="in" units="kelvin" />
2602    <variable name="F" public_interface="in" units="faradays_constant_units" /> 
2603    
2604    <!-- This variable is imported from an encapsulated component. -->
2605    <variable name="K1_infinity" private_interface="in" units="dimensionless" />
2606    
2607    <rdf:RDF
2608      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2609      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2610      <rdf:Description rdf:about="#g_K1_calculation_eq">
2611        <cmeta:comment rdf:parseType="Resource">
2612          <rdf:value>
2613            Calculation of the maximal channel conductance, dependent on
2614            extracellular potassium concentration.
2615          </rdf:value>
2616        </cmeta:comment>
2617      </rdf:Description>
2618    </rdf:RDF>
2619    <math xmlns="http://www.w3.org/1998/Math/MathML"
2620      cmeta:id="g_K1_calculation_eq">
2621      <apply id="g_K1_calculation"><eq />
2622        <ci> g_K1 </ci>
2623        <apply><times />
2624          <ci>g_K1_max</ci>
2625          <apply><root />
2626            <apply><divide />
2627              <ci> Ko </ci>
2628              <cn cellml:units="mM"> 5.4 </cn>
2629            </apply>
2630          </apply>
2631        </apply>
2632      </apply>
2633    </math>
2634        
2635    <rdf:RDF
2636      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2637      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2638      <rdf:Description rdf:about="#E_K1_calculation_eq">
2639        <cmeta:comment rdf:parseType="Resource">
2640          <rdf:value>
2641            The following equation calculates the reversal potential of the
2642            time-independent potassium current.
2643          </rdf:value>
2644        </cmeta:comment>
2645      </rdf:Description>
2646    </rdf:RDF>
2647    <math xmlns="http://www.w3.org/1998/Math/MathML"
2648      cmeta:id="E_K1_calculation_eq">
2649      <apply id="E_K1_calculation"><eq />
2650        <ci> E_K1 </ci>
2651        <apply><times />
2652          <apply><divide />
2653            <apply><times />
2654              <ci> R </ci>
2655              <ci> T </ci>
2656            </apply>
2657            <ci> F </ci>
2658          </apply>
2659          <apply><ln />
2660            <apply><divide />
2661              <ci> Ko </ci>
2662              <ci> Ki </ci>
2663            </apply>
2664          </apply>
2665        </apply>
2666      </apply>
2667    </math>
2668        
2669    <rdf:RDF
2670      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2671      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2672      <rdf:Description rdf:about="#i_K1_calculation_eq">
2673        <cmeta:comment rdf:parseType="Resource">
2674          <rdf:value>
2675            Calculate the current.
2676          </rdf:value>
2677        </cmeta:comment>
2678      </rdf:Description>
2679    </rdf:RDF>
2680    <math xmlns="http://www.w3.org/1998/Math/MathML"
2681      cmeta:id="i_K1_calculation_eq">
2682      <apply id="i_K1_calculation"><eq />
2683        <ci> i_K1 </ci>
2684        <apply><times />
2685          <ci> g_K1 </ci>
2686          <ci> K1_infinity </ci>
2687          <apply><minus />     
2688            <ci> V </ci>
2689            <ci> E_K1 </ci>
2690          </apply>
2691        </apply>
2692      </apply>
2693    </math>
2694  </component>
2695        
2696        
2697  <!--
2698    The "time_independent_potassium_current_K1_gate" component is the K1 gate   
2699    encapsulated in the time-independent potassium current.
2700  -->
2701  <component name="time_independent_potassium_current_K1_gate"
2702    cmeta:id="time_independent_potassium_current_K1_gate">
2703    <rdf:RDF
2704      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2705      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2706      <rdf:Description rdf:about="#time_independent_potassium_current_K1_gate">
2707        <cmeta:comment rdf:parseType="Resource">
2708          <rdf:value>
2709            The time constants for the K1 gate are small enough that the gating
2710            variable can be approximated with it's steady-state value.
2711          </rdf:value>
2712        </cmeta:comment>
2713      </rdf:Description>
2714    </rdf:RDF>
2715
2716    <!-- This variable is defined here and used in other components. -->
2717    <variable name="K1_infinity" public_interface="out" units="dimensionless" /> 
2718    <!-- These variables are defined here and only used internally. -->
2719    <variable name="alpha_K1" units="per_ms" />
2720    <variable name="beta_K1" units="per_ms" />
2721    
2722    <!-- 
2723      These variables are imported from the "environment", "membrane" and       
2724      "time_independent_potassium_current" components.
2725    -->
2726    <variable name="V" public_interface="in" units="mV" />
2727    <variable name="time" public_interface="in" units="ms" />
2728    <variable name="E_K1" public_interface="in" units="mV" />
2729    
2730    <rdf:RDF
2731      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2732      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2733      <rdf:Description rdf:about="#alpha_K1_calculation_eq">
2734        <cmeta:comment rdf:parseType="Resource">
2735          <rdf:value>
2736            The opening rate of the K1 gate.
2737          </rdf:value>
2738        </cmeta:comment>
2739      </rdf:Description>
2740    </rdf:RDF>
2741    <math xmlns="http://www.w3.org/1998/Math/MathML"
2742      cmeta:id="alpha_K1_calculation_eq">
2743      <apply id="alpha_K1_calculation"><eq />
2744        <ci> alpha_K1 </ci>
2745        <apply><divide />
2746          <cn cellml:units="per_ms"> 1.02 </cn>
2747          <apply><plus />
2748            <cn cellml:units="dimensionless"> 1.0 </cn>
2749            <apply><exp />
2750              <apply><times />
2751                <cn cellml:units="per_mV"> 0.2385 </cn>
2752                <apply><minus />
2753                  <apply><minus />
2754                    <ci> V </ci>
2755                    <ci> E_K1 </ci>
2756                  </apply>
2757                  <cn cellml:units="mV"> 59.215 </cn>
2758                </apply>
2759              </apply>
2760            </apply>
2761          </apply>
2762        </apply>
2763      </apply>
2764    </math>
2765          
2766    <rdf:RDF
2767      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2768      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2769      <rdf:Description rdf:about="#beta_K1_calculation_eq">
2770        <cmeta:comment rdf:parseType="Resource">
2771          <rdf:value>
2772            The closing rate of the K1 gate.
2773          </rdf:value>
2774        </cmeta:comment>
2775      </rdf:Description>
2776    </rdf:RDF>
2777    <math xmlns="http://www.w3.org/1998/Math/MathML"
2778      cmeta:id="beta_K1_calculation_eq">
2779      <apply id="beta_K1_calculation"><eq />
2780        <ci> beta_K1 </ci>
2781        <apply><divide />
2782          <apply><plus />
2783            <apply><times />
2784              <cn cellml:units="per_ms"> 0.49124 </cn>
2785              <apply><exp />
2786                <apply><times />
2787                  <cn cellml:units="dimensionless"> 0.08032 </cn>
2788                  <apply><minus />
2789                    <apply><plus />
2790                      <ci> V </ci>
2791                      <cn cellml:units="mV"> 5.476 </cn>
2792                    </apply>
2793                    <ci> E_K1 </ci>
2794                  </apply>
2795                </apply>
2796              </apply>
2797            </apply>
2798            <apply><exp />
2799              <apply><times />
2800                <cn cellml:units="dimensionless"> 0.06175 </cn>
2801                <apply><minus />
2802                  <ci> V </ci>
2803                  <apply><plus />
2804                    <ci> E_K1 </ci>
2805                    <cn cellml:units="mV"> 594.31 </cn>
2806                  </apply>
2807                </apply>
2808              </apply>
2809            </apply>
2810          </apply>
2811          <apply><plus />
2812            <cn cellml:units="dimensionless"> 1.0 </cn>
2813            <apply><exp />
2814              <apply><times />
2815                <cn cellml:units="per_mV"> -0.5143 </cn>
2816                <apply><plus />
2817                  <apply><minus />
2818                    <ci> V </ci>
2819                    <ci> E_K1 </ci>
2820                  </apply>
2821                  <cn cellml:units="mV"> 4.753 </cn>
2822                </apply>
2823              </apply>
2824            </apply>
2825          </apply>
2826        </apply>
2827      </apply>
2828    </math>
2829          
2830    <rdf:RDF
2831      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2832      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2833      <rdf:Description rdf:about="#K1_infinity_calculation_eq">
2834        <cmeta:comment rdf:parseType="Resource">
2835          <rdf:value>
2836            The steady-state approximation for the K1 gating kinetics.
2837          </rdf:value>
2838        </cmeta:comment>
2839      </rdf:Description>
2840    </rdf:RDF>
2841    <math xmlns="http://www.w3.org/1998/Math/MathML"
2842      cmeta:id="K1_infinity_calculation_eq">
2843      <apply id="K1_infinity_calculation"><eq />
2844        <ci> K1_infinity </ci>
2845        <apply><divide />
2846          <ci> alpha_K1 </ci>
2847          <apply><plus />
2848            <ci> alpha_K1 </ci>
2849            <ci> beta_K1 </ci>
2850          </apply>
2851        </apply>
2852      </apply>
2853    </math>
2854  </component>
2855  
2856  
2857  <!--  
2858      The "plateau_potassium_current" component contains the equations          
2859      which describe the contribution of a time independent                    
2860      [K]o-insensitive channel at plateau potentials. 
2861  -->
2862  <component name="plateau_potassium_current"
2863    cmeta:id="plateau_potassium_current">
2864    <rdf:RDF
2865      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2866      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2867      <rdf:Description rdf:about="#plateau_potassium_current">
2868        <cmeta:comment rdf:parseType="Resource">
2869          <rdf:value>
2870            The plateau potassium current component contains the equations which
2871            describe the contribution of a time independent [K]o-insensitive
2872            channel at plateau potentials.
2873          </rdf:value>
2874        </cmeta:comment>
2875      </rdf:Description>
2876    </rdf:RDF>
2877
2878    <!-- This variable is defined here and used in other components. -->
2879    <variable name="i_Kp" public_interface="out" units="uA_per_mm2" />
2880    
2881    <!-- These variables are defined here and only used internally.  -->
2882    <variable name="E_Kp" units="mV" />
2883    <variable name="g_Kp" initial_value="8.28e-5" units="mS_per_mm2" />
2884    <variable name="Kp" units="dimensionless" />
2885    
2886    <!-- These variables are imported from other components. -->
2887    <variable name="time" public_interface="in" units="ms" />
2888    <variable name="V" public_interface="in" units="mV" />
2889    <variable name="E_K1" public_interface="in" units="mV" />
2890    
2891    <rdf:RDF
2892      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2893      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2894      <rdf:Description rdf:about="#E_Kp_calculation_eq">
2895        <cmeta:comment rdf:parseType="Resource">
2896          <rdf:value>
2897            The channel's reversal potential.
2898          </rdf:value>
2899        </cmeta:comment>
2900      </rdf:Description>
2901    </rdf:RDF>
2902    <math xmlns="http://www.w3.org/1998/Math/MathML"
2903      cmeta:id="E_Kp_calculation_eq">
2904      <apply id="E_Kp_calculation"><eq />
2905        <ci> E_Kp </ci>
2906        <ci> E_K1 </ci>
2907      </apply>
2908    </math>
2909      
2910    <rdf:RDF
2911      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2912      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2913      <rdf:Description rdf:about="#Kp_calculation_eq">
2914        <cmeta:comment rdf:parseType="Resource">
2915          <rdf:value>
2916            The activation variable.
2917          </rdf:value>
2918        </cmeta:comment>
2919      </rdf:Description>
2920    </rdf:RDF>
2921    <math xmlns="http://www.w3.org/1998/Math/MathML"
2922      cmeta:id="Kp_calculation_eq">
2923      <apply id="Kp_calculation"><eq />
2924        <ci> Kp </ci>
2925        <apply><divide />
2926          <cn cellml:units="dimensionless"> 1.0 </cn>
2927          <apply><plus />
2928            <cn cellml:units="dimensionless"> 1.0 </cn>
2929            <apply><exp />
2930              <apply><divide />
2931                <apply><minus />
2932                  <cn cellml:units="mV"> 7.488 </cn>
2933                  <ci> V </ci>
2934                </apply>
2935                <cn cellml:units="mV"> 5.98 </cn>
2936              </apply>
2937            </apply> 
2938          </apply>
2939        </apply>
2940      </apply>
2941    </math>
2942      
2943    <rdf:RDF
2944      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2945      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2946      <rdf:Description rdf:about="#i_Kp_calculation_eq">
2947        <cmeta:comment rdf:parseType="Resource">
2948          <rdf:value>
2949            Calculation of the plateau potassium current.
2950          </rdf:value>
2951        </cmeta:comment>
2952      </rdf:Description>
2953    </rdf:RDF>
2954    <math xmlns="http://www.w3.org/1998/Math/MathML"
2955      cmeta:id="i_Kp_calculation_eq">
2956      <apply id="i_Kp_calculation"><eq />
2957        <ci> i_Kp </ci>
2958        <apply><times />
2959          <ci> g_Kp </ci>
2960          <ci> Kp </ci>
2961          <apply><minus />
2962            <ci> V </ci>
2963            <ci> E_Kp </ci>
2964          </apply>
2965        </apply>
2966      </apply>
2967    </math>
2968  </component>
2969  
2970  
2971  <!--
2972    The "Na_Ca_exchanger" component describes how a protein molecule in the cell
2973    surface membrane transports Na ions into the cytosol and exports Ca ions    
2974    into the extracellular matrix, in a ratio of 3:1 respectively.
2975  -->
2976  <component name="Na_Ca_exchanger" cmeta:id="Na_Ca_exchanger">
2977    <rdf:RDF
2978      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
2979      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
2980      <rdf:Description rdf:about="#Na_Ca_exchanger">
2981        <cmeta:comment rdf:parseType="Resource">
2982          <rdf:value>
2983            The Na/Ca exchanger component describes how a protein molecule in
2984            the cell surface membrane transports Na ions into the cytosol and
2985            exports Ca ions into the extracellular volume, in a ratio of 3:1
2986            respectively.
2987          </rdf:value>
2988        </cmeta:comment>
2989      </rdf:Description>
2990    </rdf:RDF>
2991
2992    <!--  This variable is defined here and used in other components. -->
2993    
2994    <variable name="i_NaCa" public_interface="out" units="uA_per_mm2" />
2995    
2996    <!-- These variables are defined here and only used internally. -->
2997    <variable name="k_NaCa" initial_value="50.0" units="uA_per_mm2" />
2998    <variable name="K_mNa" initial_value="87.5" units="mM" />
2999    <variable name="K_mCa" initial_value="1.38" units="mM" />
3000    <variable name="k_sat" initial_value="0.1" units="dimensionless" />
3001    <variable name="eta" initial_value="0.35" units="dimensionless" />
3002    
3003    <!-- These variables are imported in from other components. -->
3004    <variable name="time" public_interface="in" units="ms" />
3005    <variable name="V" public_interface="in" units="mV" />
3006    <variable name="R" public_interface="in" units="gas_constant_units" />
3007    <variable name="T" public_interface="in" units="kelvin" />
3008    <variable name="F" public_interface="in" units="faradays_constant_units" />
3009    <variable name="Nai" public_interface="in" units="mM" />
3010    <variable name="Nao" public_interface="in" units="mM" />
3011    <variable name="Cai" public_interface="in" units="mM" />
3012    <variable name="Cao" public_interface="in" units="mM" />
3013    
3014    <rdf:RDF
3015      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3016      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3017      <rdf:Description rdf:about="#Na_Ca_exchanger_eq">
3018        <cmeta:comment rdf:parseType="Resource">
3019          <rdf:value>
3020            Calculation of the Na/Ca exchanger current.
3021          </rdf:value>
3022        </cmeta:comment>
3023      </rdf:Description>
3024    </rdf:RDF>
3025    <math xmlns="http://www.w3.org/1998/Math/MathML"
3026      cmeta:id="Na_Ca_exchanger_eq">
3027      <apply id="Na_Ca_exchanger"><eq />
3028        <ci> i_NaCa </ci>
3029        <apply><times /> 
3030          <ci> k_NaCa </ci>
3031          <apply><divide />
3032            <cn cellml:units="dimensionless"> 1.0 </cn>
3033            <apply><plus />
3034              <apply><power />
3035                <ci> K_mNa </ci>
3036                <cn cellml:units="dimensionless"> 3.0 </cn>
3037              </apply>
3038              <apply><power />
3039                <ci> Nao </ci>
3040                <cn cellml:units="dimensionless"> 3.0 </cn>
3041              </apply>
3042            </apply>
3043          </apply>
3044          <apply><divide />
3045            <cn cellml:units="dimensionless"> 1.0 </cn>
3046            <apply><plus />
3047              <ci> K_mCa </ci>
3048              <ci> Cao </ci>
3049            </apply>
3050          </apply>
3051          <apply><divide />
3052            <cn cellml:units="dimensionless"> 1.0 </cn>
3053            <apply><plus />
3054              <cn cellml:units="dimensionless"> 1.0 </cn>
3055              <apply><times />
3056                <ci> k_sat </ci>
3057                <apply><exp />
3058                  <apply><times />
3059                    <apply><minus />
3060                      <ci> eta </ci>
3061                      <cn cellml:units="dimensionless"> 1.0 </cn>
3062                    </apply>
3063                    <ci> V </ci>
3064                    <apply><divide />
3065                      <ci> F </ci>
3066                      <apply><times />
3067                        <ci> R </ci>
3068                        <ci> T </ci>
3069                      </apply>
3070                    </apply>
3071                  </apply>
3072                </apply>
3073              </apply>
3074            </apply>
3075          </apply>
3076          <apply><minus />
3077            <apply><times />
3078              <apply><exp />
3079                <apply><times />
3080                  <ci> eta </ci>
3081                  <ci> V </ci>
3082                  <apply><divide />
3083                    <ci> F </ci>
3084                    <apply><times />
3085                      <ci> R </ci>
3086                      <ci> T </ci>
3087                    </apply>
3088                  </apply>
3089                </apply>
3090              </apply>
3091              <apply><power />
3092                <ci> Nai </ci>
3093                <cn cellml:units="dimensionless"> 3.0 </cn>
3094              </apply>
3095              <ci> Cao </ci>
3096            </apply>
3097            <apply><times />
3098              <apply><exp />
3099                <apply><times />
3100                  <apply><minus />
3101                    <ci> eta </ci>
3102                    <cn cellml:units="dimensionless"> 1.0 </cn>
3103                  </apply>
3104                  <ci> V </ci>
3105                  <apply><divide />
3106                    <ci> F </ci>
3107                    <apply><times />
3108                      <ci> R </ci>
3109                      <ci> T </ci>
3110                    </apply>
3111                  </apply>
3112                </apply>
3113              </apply>
3114              <apply><power />
3115                <ci> Nao </ci>
3116                <cn cellml:units="dimensionless"> 3.0 </cn>
3117              </apply>
3118              <ci> Cai </ci>
3119            </apply>
3120          </apply>
3121        </apply>
3122      </apply>
3123    </math>
3124  </component>
3125  
3126  
3127  <!--
3128    The "sarcolemmal_calcium_pump" is an additional mechanism for removing Ca   
3129    ions from the myoplasm to help maintain a low intracellular calcium         
3130    concentration when at rest.
3131  -->
3132  <component name="sarcolemmal_calcium_pump"
3133    cmeta:id="sarcolemmal_calcium_pump">
3134    <rdf:RDF
3135      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3136      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3137      <rdf:Description rdf:about="#sarcolemmal_calcium_pump">
3138        <cmeta:comment rdf:parseType="Resource">
3139          <rdf:value>
3140            The sarcolemmal calcium pump is an additional mechanism for removing
3141            Ca ions from the myoplasm to help maintain a low intracellular
3142            calcium concentration when at rest.
3143          </rdf:value>
3144        </cmeta:comment>
3145      </rdf:Description>
3146    </rdf:RDF>
3147
3148    <!--  This variable is defined here and used in other components. -->
3149    <variable name="i_p_Ca" public_interface="out" units="uA_per_mm2" />
3150    
3151    <!-- These variables are defined here and only used internally. -->
3152    <variable name="K_mpCa" initial_value="0.5e-3" units="mM" />
3153    <variable name="I_pCa" initial_value="1.15e-2" units="uA_per_mm2" />
3154    
3155    <!-- These variables are imported from other components.  -->
3156    <variable name="time" public_interface="in" units="ms" />
3157    <variable name="Cai" public_interface="in" units="mM" />   
3158 
3159    <rdf:RDF
3160      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3161      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3162      <rdf:Description rdf:about="#i_p_Ca_calculation_eq">
3163        <cmeta:comment rdf:parseType="Resource">
3164          <rdf:value>
3165            The calcium pump current.
3166          </rdf:value>
3167        </cmeta:comment>
3168      </rdf:Description>
3169    </rdf:RDF>
3170    <math xmlns="http://www.w3.org/1998/Math/MathML"
3171      cmeta:id="i_p_Ca_calculation_eq">
3172      <apply id="i_p_Ca_calculation"><eq />
3173        <ci> i_p_Ca </ci>
3174        <apply><times />
3175          <ci> I_pCa </ci>
3176          <apply><divide />
3177            <ci> Cai </ci>
3178            <apply><plus />
3179              <ci> K_mpCa </ci>
3180              <ci> Cai </ci>
3181            </apply>
3182          </apply>
3183        </apply>
3184      </apply>
3185    </math>
3186  </component>
3187  
3188  <!-- 
3189    The "sodium_background_current" is a time-independent diffusion of Na ions  
3190    down their electrochemical gradient, through the cell surface membrane into 
3191    the cytosol.
3192  -->
3193  <component name="sodium_background_current"
3194    cmeta:id="sodium_background_current">
3195    <rdf:RDF
3196      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3197      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3198      <rdf:Description rdf:about="#sodium_background_current">
3199        <cmeta:comment rdf:parseType="Resource">
3200          <rdf:value>
3201            The sodium background current is a time-independent diffusion of
3202            Na ions down their electrochemical gradient, through the cell
3203            surface membrane into the cytosol.
3204          </rdf:value>
3205        </cmeta:comment>
3206      </rdf:Description>
3207    </rdf:RDF>
3208
3209    <!--  This variable is defined here and used in other components. -->
3210    <variable name="i_Na_b" public_interface="out" units="uA_per_mm2" />
3211    
3212    <!-- These variables are defined here and only used internally. -->
3213    <variable name="g_Nab" initial_value="1.41e-5" units="mS_per_mm2" />
3214    <variable name="E_NaN" units="mV" />
3215    
3216    <!-- 
3217        Time and membrane potential are imported from the "environment" and the
3218        "membrane" components.  The reversal potential is imported from the     
3219        "fast_sodium_current" component. 
3220    -->
3221    <variable name="time" public_interface="in" units="ms" />
3222    <variable name="V" public_interface="in" units="mV" />
3223    <variable name="E_Na" public_interface="in" units="mV" /> 
3224    
3225    <rdf:RDF
3226      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3227      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3228      <rdf:Description rdf:about="#E_NaN_calculation_eq">
3229        <cmeta:comment rdf:parseType="Resource">
3230          <rdf:value>
3231            The reversal potential for the background sodium channel.
3232          </rdf:value>
3233        </cmeta:comment>
3234      </rdf:Description>
3235    </rdf:RDF>
3236    <math xmlns="http://www.w3.org/1998/Math/MathML"
3237      cmeta:id="E_NaN_calculation_eq"> 
3238      <apply id="E_NaN_calculation"><eq />
3239        <ci> E_NaN </ci>
3240        <ci> E_Na </ci>
3241      </apply>
3242    </math>
3243      
3244    <rdf:RDF
3245      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3246      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3247      <rdf:Description rdf:about="#i_Na_b_calculation_eq">
3248        <cmeta:comment rdf:parseType="Resource">
3249          <rdf:value>
3250            Calculation of the background sodium current.
3251          </rdf:value>
3252        </cmeta:comment>
3253      </rdf:Description>
3254    </rdf:RDF>
3255    <math xmlns="http://www.w3.org/1998/Math/MathML"
3256      cmeta:id="i_Na_b_calculation_eq"> 
3257      <apply id="i_Na_b_calculation"><eq />
3258        <ci> i_Na_b </ci>
3259        <apply><times />
3260          <ci> g_Nab </ci>
3261          <apply><minus />
3262            <ci> V </ci>
3263            <ci> E_NaN </ci>
3264          </apply>
3265        </apply>
3266      </apply>
3267    </math>
3268  </component>
3269  
3270  <!--
3271    The "calcium_background_current" describes a time-independent diffusion of  
3272    Ca ions down their electrochemical gradient through the cell surface        
3273    membrane into the cytosol.  However, calcium is not allowed to accumulate to
3274    high intracellular concentrations.  This influx is balanced by the Ca ion   
3275    extrusion through the Na-Ca exchanger and the sarcolemmal Ca pump. 
3276  -->
3277  <component name="calcium_background_current"
3278    cmeta:id="calcium_background_current">
3279    <rdf:RDF
3280      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3281      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3282      <rdf:Description rdf:about="#calcium_background_current">
3283        <cmeta:comment rdf:parseType="Resource">
3284          <rdf:value>
3285            The calcium background current describes a time-independent
3286            diffusion of Ca ions down their electrochemical gradient through the
3287            cell surface membrane into the cytosol. However, calcium is not
3288            allowed to accumulate to high intracellular concentrations. This
3289            influx is balanced by the Ca ion extrusion through the Na-Ca
3290            exchanger and the sarcolemmal Ca pump.
3291          </rdf:value>
3292        </cmeta:comment>
3293      </rdf:Description>
3294    </rdf:RDF>
3295
3296    <!--  This variable is defined here and used in other components. -->
3297    <variable name="i_Ca_b" public_interface="out" units="uA_per_mm2" />
3298    
3299    <!-- These variables are defined here and only used internally. -->
3300    <variable name="g_Cab" initial_value="6.032e-5" units="mS_per_mm2" />
3301    <variable name="E_CaN" units="mV" />
3302    
3303    <!-- These variables are imported from other components. -->
3304    <variable name="time" public_interface="in" units="ms" />
3305    <variable name="V" public_interface="in" units="mV" />
3306    <variable name="R" public_interface="in" units="gas_constant_units" />
3307    <variable name="T" public_interface="in" units="kelvin" />
3308    <variable name="F" public_interface="in" units="faradays_constant_units" />
3309    <variable name="Cai" public_interface="in" units="mM" />
3310    <variable name="Cao" public_interface="in" units="mM" />
3311    
3312    <rdf:RDF
3313      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3314      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3315      <rdf:Description rdf:about="#E_CaN_calculation_eq">
3316        <cmeta:comment rdf:parseType="Resource">
3317          <rdf:value>
3318            The reversal potential for the background calcium current.
3319          </rdf:value>
3320        </cmeta:comment>
3321      </rdf:Description>
3322    </rdf:RDF>
3323    <math xmlns="http://www.w3.org/1998/Math/MathML"
3324      cmeta:id="E_CaN_calculation_eq">
3325      <apply id="E_CaN_calculation"><eq />
3326        <ci> E_CaN </ci>
3327        <apply><times />
3328          <apply><divide />
3329            <apply><times />
3330              <ci> R </ci>
3331              <ci> T </ci>
3332            </apply>
3333            <apply><times />
3334              <cn cellml:units="dimensionless"> 2.0 </cn>
3335              <ci> F </ci>
3336            </apply>
3337          </apply>
3338          <apply><ln />
3339            <apply><divide />
3340              <ci> Cao </ci>
3341              <ci> Cai </ci>
3342            </apply>
3343          </apply>
3344        </apply>
3345      </apply>
3346    </math>
3347      
3348    <rdf:RDF
3349      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3350      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3351      <rdf:Description rdf:about="#i_Ca_b_calculation_eq">
3352        <cmeta:comment rdf:parseType="Resource">
3353          <rdf:value>
3354            Calculation of the background calcium current.
3355          </rdf:value>
3356        </cmeta:comment>
3357      </rdf:Description>
3358    </rdf:RDF>
3359    <math xmlns="http://www.w3.org/1998/Math/MathML"
3360      cmeta:id="i_Ca_b_calculation_eq">
3361      <apply id="i_Ca_b_calculation"><eq />
3362        <ci> i_Ca_b </ci>
3363        <apply><times />
3364          <ci> g_Cab </ci>
3365          <apply><minus />
3366            <ci> V </ci>
3367            <ci> E_CaN </ci>
3368          </apply>
3369        </apply>
3370      </apply>
3371    </math>
3372  </component>
3373  
3374  <!-- 
3375    The "sodium_potassium_pump" is an active protein in the cell membrane which 
3376    couples the free energy released by the hydrolysis of ATP to the movement of
3377    Na and K ions against their electrochemical gradients through the cell      
3378    surface membrane.
3379  -->
3380  <component name="sodium_potassium_pump" cmeta:id="sodium_potassium_pump">
3381    <rdf:RDF
3382      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3383      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3384      <rdf:Description rdf:about="#sodium_potassium_pump">
3385        <cmeta:comment rdf:parseType="Resource">
3386          <rdf:value>
3387            The sodium potassium pump is an active protein in the cell membrane
3388            which couples the free energy released by the hydrolysis of ATP to
3389            the movement of Na and K ions against their electrochemical
3390            gradients through the cell membrane.
3391          </rdf:value>
3392        </cmeta:comment>
3393      </rdf:Description>
3394    </rdf:RDF>
3395
3396    <!--  This variable is defined here and used in other components. -->
3397    <variable name="i_NaK" public_interface="out" units="uA_per_mm2" />
3398    
3399    <!-- These variables are defined here and only used internally. -->
3400    <variable name="I_NaK" initial_value="0.013" units="uA_per_mm2" />
3401    <variable name="f_NaK" units="dimensionless" />
3402    <variable name="K_mNai" initial_value="10.0" units="mM" />
3403    <variable name="K_mKo" initial_value="1.5" units="mM" />
3404    <variable name="sigma" units="dimensionless" />
3405    
3406    <!-- These variables are imported from other components.  -->
3407    <variable name="time" public_interface="in" units="ms" />
3408    <variable name="V" public_interface="in" units="mV" />
3409    <variable name="R" public_interface="in" units="gas_constant_units" />
3410    <variable name="T" public_interface="in" units="kelvin" />
3411    <variable name="F" public_interface="in" units="faradays_constant_units" />  
3412    <variable name="Nai" public_interface="in" units="mM" />
3413    <variable name="Nao" public_interface="in" units="mM" />   
3414    <variable name="Ko" public_interface="in" units="mM" />
3415    
3416    <rdf:RDF
3417      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3418      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3419      <rdf:Description rdf:about="#f_NaK_calculation_eq">
3420        <cmeta:comment rdf:parseType="Resource">
3421          <rdf:value>
3422            Calculation of the Na/K pump current.
3423          </rdf:value>
3424        </cmeta:comment>
3425      </rdf:Description>
3426    </rdf:RDF>
3427    <math xmlns="http://www.w3.org/1998/Math/MathML"
3428      cmeta:id="f_NaK_calculation_eq">
3429      <apply id="f_NaK_calculation"><eq />
3430        <ci> f_NaK </ci>
3431        <apply><divide />
3432          <cn cellml:units="dimensionless"> 1.0 </cn>
3433          <apply><plus />
3434            <apply><plus />
3435              <cn cellml:units="dimensionless"> 1.0 </cn>
3436              <apply><times />
3437                <cn cellml:units="dimensionless"> 0.1245 </cn>
3438                <apply><exp />
3439                  <apply><divide />
3440                    <apply><times />
3441                      <cn cellml:units="dimensionless"> -0.1 </cn>
3442                      <ci> V </ci>
3443                      <ci> F </ci>
3444                    </apply>
3445                    <apply><times />
3446                      <ci> R </ci>
3447                      <ci> T </ci>
3448                    </apply>
3449                  </apply>
3450                </apply>
3451              </apply>
3452            </apply>
3453            <apply><times />
3454              <cn cellml:units="dimensionless"> 0.0365 </cn>
3455              <ci> sigma </ci>
3456              <apply><exp />
3457                <apply><divide />
3458                  <apply><times />
3459                    <apply><minus />
3460                      <ci> V </ci>
3461                    </apply>
3462                    <ci> F </ci>
3463                  </apply>
3464                  <apply><times />
3465                    <ci> R </ci>
3466                    <ci> T </ci>
3467                  </apply>
3468                </apply>
3469              </apply>
3470            </apply>
3471          </apply>
3472        </apply>
3473      </apply>
3474    </math>
3475    <math xmlns="http://www.w3.org/1998/Math/MathML"
3476      cmeta:id="sigma_calculation_eq">
3477      <apply id="sigma_calculation"><eq />
3478        <ci> sigma </ci>
3479        <apply><times />
3480          <apply><divide />
3481            <cn cellml:units="dimensionless"> 1.0 </cn>
3482            <cn cellml:units="dimensionless"> 7.0 </cn>
3483          </apply>
3484          <apply><minus />
3485            <apply><exp />
3486              <apply><divide />
3487                <ci> Nao </ci>
3488                <cn cellml:units="dimensionless"> 67.3 </cn>
3489              </apply>
3490            </apply>
3491            <cn cellml:units="dimensionless"> 1.0 </cn>
3492          </apply>
3493        </apply>
3494      </apply>
3495    </math>
3496    <math xmlns="http://www.w3.org/1998/Math/MathML"
3497      cmeta:id="i_NaK_calculation_eq">
3498      <apply id="i_NaK_calculation"><eq />
3499        <ci> i_NaK </ci>
3500        <apply><times />
3501          <ci> I_NaK </ci>
3502          <ci> f_NaK </ci>
3503          <apply><divide />
3504            <cn cellml:units="dimensionless"> 1.0 </cn>
3505            <apply><plus />
3506              <cn cellml:units="dimensionless"> 1.0 </cn>
3507              <apply><power />
3508                <apply><divide />
3509                  <ci> K_mNai </ci>
3510                  <ci> Nai </ci>
3511                </apply>
3512                <cn cellml:units="dimensionless"> 1.5 </cn>
3513              </apply>
3514            </apply>
3515          </apply>
3516          <apply><divide />
3517            <ci> Ko </ci>
3518            <apply><plus />
3519              <ci> Ko </ci>
3520              <ci> K_mKo </ci>
3521            </apply>
3522          </apply>
3523        </apply>
3524      </apply>
3525    </math>
3526  </component>
3527  
3528  <!--
3529    The "non_specific_calcium_activated_current" describes a channel which is
3530    activated by calcium ions, but is permeable to only sodium and potassium    
3531    ions.
3532  -->
3533  <component name="non_specific_calcium_activated_current"
3534    cmeta:id="non_specific_calcium_activated_current">\
3535    <rdf:RDF
3536      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3537      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3538      <rdf:Description rdf:about="#non_specific_calcium_activated_current">
3539        <cmeta:comment rdf:parseType="Resource">
3540          <rdf:value>
3541            The nonspecific calcium activated current describes a channel which
3542            is activated by calcium ions, but is permeable to only sodium and
3543            potassium ions.
3544          </rdf:value>
3545        </cmeta:comment>
3546      </rdf:Description>
3547    </rdf:RDF>
3548
3549    <!--  These variables are defined here and used in other components. -->
3550    <variable name="i_ns_Ca" public_interface="out" units="uA_per_mm2" />
3551    <variable name="i_ns_Na" public_interface="out" units="uA_per_mm2" />
3552    <variable name="i_ns_K" public_interface="out" units="uA_per_mm2" />
3553    
3554    <!-- These variables are defined here and only used internally. -->
3555    <variable name="I_ns_Ca" units="uA_per_mm2" />
3556    <variable name="I_ns_Na" units="uA_per_mm2" />
3557    <variable name="I_ns_K" units="uA_per_mm2" />
3558    <variable name="K_m_ns_Ca" initial_value="1.2e-3" units="mM" />
3559    <variable name="P_ns_Ca" initial_value="1.75e-9" units="mm_per_ms" />
3560    <variable name="EnsCa" units="mV"/>
3561    <variable name="VnsCa" units="mV"/>
3562    
3563    <!-- 
3564      Time and membrane potential are imported from the "environment" and the   
3565      "membrane" components.  Intracellular calcium concentration is imported   
3566      from the "ionic_concentrations" component. 
3567    -->
3568    <variable name="time" public_interface="in" units="ms" />
3569    <variable name="Cai" public_interface="in" units="mM" />
3570    <variable name="V" public_interface="in" units="mV" />
3571    <variable name="R" public_interface="in" units="gas_constant_units" />
3572    <variable name="T" public_interface="in" units="kelvin" />
3573    <variable name="F" public_interface="in" units="faradays_constant_units" />
3574    <variable name="Nao" public_interface="in" units="mM" />
3575    <variable name="Ko" public_interface="in" units="mM" />
3576    <variable name="Nai" public_interface="in" units="mM" />
3577    <variable name="Ki" public_interface="in" units="mM" />
3578    
3579    <rdf:RDF
3580      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3581      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3582      <rdf:Description rdf:about="#EnsCa_calculation_eq">
3583        <cmeta:comment rdf:parseType="Resource">
3584          <rdf:value>
3585            The reversal potential of the channel.
3586          </rdf:value>
3587        </cmeta:comment>
3588      </rdf:Description>
3589    </rdf:RDF>
3590    <math xmlns="http://www.w3.org/1998/Math/MathML"
3591      cmeta:id="EnsCa_calculation_eq">
3592      <apply id="EnsCa_calculation"><eq/>
3593        <ci>EnsCa</ci>
3594        <apply><times />
3595          <apply><divide />
3596            <apply><times />
3597              <ci> R </ci>
3598              <ci> T </ci>
3599            </apply>
3600            <ci> F </ci>
3601          </apply>
3602          <apply><ln />
3603            <apply><divide />
3604              <apply><plus/>
3605                <ci> Ko </ci>
3606                <ci> Nao </ci>
3607              </apply>
3608              <apply><plus/>
3609                <ci> Ki </ci>
3610                <ci> Nai </ci>
3611              </apply>
3612            </apply>
3613          </apply>
3614        </apply>
3615      </apply>
3616    </math>
3617      
3618    <rdf:RDF
3619      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3620      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3621      <rdf:Description rdf:about="#VnsCa_calculation_eq">
3622        <cmeta:comment rdf:parseType="Resource">
3623          <rdf:value>
3624            The potential offset for the channel.
3625          </rdf:value>
3626        </cmeta:comment>
3627      </rdf:Description>
3628    </rdf:RDF>
3629    <math xmlns="http://www.w3.org/1998/Math/MathML"
3630      cmeta:id="VnsCa_calculation_eq">
3631      <apply id="VnsCa_calculation"><eq/>
3632        <ci>VnsCa</ci>
3633        <apply><minus/>
3634          <ci>V</ci>
3635          <ci>EnsCa</ci>
3636        </apply>
3637      </apply>
3638    </math>
3639      
3640    <rdf:RDF
3641      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3642      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3643      <rdf:Description rdf:about="#i_ns_Na_calculation_eq">
3644        <cmeta:comment rdf:parseType="Resource">
3645          <rdf:value>
3646            The sodium component of the channel's current.
3647          </rdf:value>
3648        </cmeta:comment>
3649      </rdf:Description>
3650    </rdf:RDF>
3651    <math xmlns="http://www.w3.org/1998/Math/MathML"
3652      cmeta:id="i_ns_Na_calculation_eq">
3653      <apply id="i_ns_Na_calculation"><eq />
3654        <ci> i_ns_Na </ci>
3655        <apply><times />
3656          <ci> I_ns_Na </ci>
3657          <apply><divide />
3658            <cn cellml:units="dimensionless"> 1.0 </cn>
3659            <apply><plus />
3660              <cn cellml:units="dimensionless"> 1.0 </cn>
3661              <apply><power />
3662                <apply><divide />
3663                  <ci> K_m_ns_Ca </ci>
3664                  <ci> Cai </ci>
3665                </apply>
3666                <cn cellml:units="dimensionless"> 3.0 </cn>
3667              </apply>
3668            </apply>
3669          </apply>
3670        </apply>
3671      </apply>
3672    </math>
3673      
3674    <rdf:RDF
3675      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3676      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3677      <rdf:Description rdf:about="#i_ns_K_calculation_eq">
3678        <cmeta:comment rdf:parseType="Resource">
3679          <rdf:value>
3680            The potassium component of the channel's current.
3681          </rdf:value>
3682        </cmeta:comment>
3683      </rdf:Description>
3684    </rdf:RDF>
3685    <math xmlns="http://www.w3.org/1998/Math/MathML"
3686      cmeta:id="i_ns_K_calculation_eq">
3687      <apply id="i_ns_K_calculation"><eq />
3688        <ci> i_ns_K </ci>
3689        <apply><times />
3690          <ci> I_ns_K </ci>
3691          <apply><divide />
3692            <cn cellml:units="dimensionless"> 1.0 </cn>
3693            <apply><plus />
3694              <cn cellml:units="dimensionless"> 1.0 </cn>
3695              <apply><power />
3696                <apply><divide />
3697                  <ci> K_m_ns_Ca </ci>
3698                  <ci> Cai </ci>
3699                </apply>
3700                <cn cellml:units="dimensionless"> 3.0 </cn>
3701              </apply>
3702            </apply>
3703          </apply>
3704        </apply>
3705      </apply>
3706    </math>
3707      
3708    <rdf:RDF
3709      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3710      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3711      <rdf:Description rdf:about="#i_ns_Ca_calculation_eq">
3712        <cmeta:comment rdf:parseType="Resource">
3713          <rdf:value>
3714            The total nonspecific calcium activated current.
3715          </rdf:value>
3716        </cmeta:comment>
3717      </rdf:Description>
3718    </rdf:RDF>
3719    <math xmlns="http://www.w3.org/1998/Math/MathML"
3720      cmeta:id="i_ns_Ca_calculation_eq">
3721      <apply id="i_ns_Ca_calculation"><eq />
3722        <ci> i_ns_Ca </ci>
3723        <apply><plus />
3724          <ci> i_ns_Na </ci>
3725          <ci> i_ns_K </ci>
3726        </apply>
3727      </apply>
3728    </math>
3729      
3730    <rdf:RDF
3731      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3732      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3733      <rdf:Description rdf:about="#I_ns_Na_max_calculation_eq">
3734        <cmeta:comment rdf:parseType="Resource">
3735          <rdf:value>
3736            The maximal sodium component current.
3737          </rdf:value>
3738        </cmeta:comment>
3739      </rdf:Description>
3740    </rdf:RDF>
3741    <math xmlns="http://www.w3.org/1998/Math/MathML"
3742      cmeta:id="I_ns_Na_max_calculation_eq">
3743      <apply id="I_ns_Na_calculation"><eq />
3744        <ci> I_ns_Na </ci>
3745        <apply><times />
3746          <ci> P_ns_Ca </ci>
3747          <apply><power />
3748            <cn cellml:units="dimensionless"> 1.0 </cn>
3749            <cn cellml:units="dimensionless"> 2.0 </cn>
3750          </apply>
3751          <apply><divide />
3752            <apply><times />
3753              <ci> VnsCa </ci>
3754              <apply><power />
3755                <ci> F </ci>
3756                <cn cellml:units="dimensionless"> 2.0 </cn>
3757              </apply>
3758            </apply>
3759            <apply><times />
3760              <ci> R </ci>
3761              <ci> T </ci>
3762            </apply>
3763          </apply>
3764          <apply><divide />
3765            <apply><minus />
3766              <apply><times />
3767                <cn cellml:units="dimensionless"> 0.75 </cn>
3768                <ci> Nai </ci>
3769                <apply><exp />
3770                  <apply><divide />
3771                    <apply><times />
3772                      <ci> VnsCa </ci>
3773                      <ci> F </ci>
3774                    </apply>
3775                    <apply><times />
3776                      <ci> R </ci> 
3777                      <ci> T </ci>
3778                    </apply>
3779                  </apply>
3780                </apply>
3781              </apply>
3782              <apply><times />
3783                <cn cellml:units="dimensionless"> 0.75 </cn>
3784                <ci> Nao </ci>
3785              </apply>
3786            </apply>
3787            <apply><minus />
3788              <apply><exp />
3789                <apply><divide />
3790                  <apply><times />
3791                    <ci> VnsCa </ci>
3792                    <ci> F </ci>
3793                  </apply>
3794                  <apply><times />
3795                    <ci> R </ci>
3796                    <ci> T </ci>
3797                  </apply>
3798                </apply>
3799              </apply>
3800              <cn cellml:units="dimensionless"> 1.0 </cn>
3801            </apply>
3802          </apply>
3803        </apply>
3804      </apply>
3805    </math>
3806      
3807    <rdf:RDF
3808      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3809      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3810      <rdf:Description rdf:about="#I_ns_K_max_calculation_eq">
3811        <cmeta:comment rdf:parseType="Resource">
3812          <rdf:value>
3813            The maximal potassium component current.
3814          </rdf:value>
3815        </cmeta:comment>
3816      </rdf:Description>
3817    </rdf:RDF>
3818    <math xmlns="http://www.w3.org/1998/Math/MathML"
3819      cmeta:id="I_ns_K_max_calculation_eq">
3820      <apply id="I_ns_K_calculation"><eq />
3821        <ci> I_ns_K </ci>
3822        <apply><times />
3823          <ci> P_ns_Ca </ci>
3824          <apply><power />
3825            <cn cellml:units="dimensionless"> 1.0 </cn>
3826            <cn cellml:units="dimensionless"> 2.0 </cn>
3827          </apply>
3828          <apply><divide />
3829            <apply><times />
3830              <ci> VnsCa </ci>
3831              <apply><power />
3832                <ci> F </ci>
3833                <cn cellml:units="dimensionless"> 2.0 </cn>
3834              </apply>
3835            </apply>
3836            <apply><times />
3837              <ci> R </ci>
3838              <ci> T </ci>
3839            </apply>
3840          </apply>
3841          <apply><divide />
3842            <apply><minus />
3843              <apply><times />
3844                <cn cellml:units="dimensionless"> 0.75 </cn>
3845                <ci> Ki </ci>
3846                <apply><exp />
3847                  <apply><divide />
3848                    <apply><times />
3849                      <ci> VnsCa </ci>
3850                      <ci> F </ci>
3851                    </apply>
3852                    <apply><times />
3853                      <ci> R </ci> 
3854                      <ci> T </ci>
3855                    </apply>
3856                  </apply>
3857                </apply>
3858              </apply>
3859              <apply><times />
3860                <cn cellml:units="dimensionless"> 0.75 </cn>
3861                <ci> Ko </ci>
3862              </apply>
3863            </apply>
3864            <apply><minus />
3865              <apply><exp />
3866                <apply><divide />
3867                  <apply><times />
3868                    <ci> VnsCa </ci>
3869                    <ci> F </ci>
3870                  </apply>
3871                  <apply><times />
3872                    <ci> R </ci>
3873                    <ci> T </ci>
3874                  </apply>
3875                </apply>
3876              </apply>
3877              <cn cellml:units="dimensionless"> 1.0 </cn>
3878            </apply>
3879          </apply>
3880        </apply>
3881      </apply>
3882    </math>
3883  </component>
3884  
3885  
3886  <!--
3887    In the JRW model, subcellular calcium regulatory mechanisms are described in
3888    detail.  There are six calcium fluxes to consider; J_rel, J_leak, J_up,     
3889    J_tr, J_xfer and J_trpn.  In addition, three membrane current fluxes are    
3890    also necessary for the formulation of calcium regulation; i_p_Ca, i_Ca_L_Ca 
3891    and i_NaCa.  The equations to calculate these fluxes are contained within   
3892    the "calcium_subsystem" component.
3893  -->
3894  <component name="calcium_subsystem" cmeta:id="calcium_subsystem">
3895    <rdf:RDF
3896      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3897      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3898      <rdf:Description rdf:about="#calcium_subsystem">
3899        <cmeta:comment rdf:parseType="Resource">
3900          <rdf:value>
3901            In the JRW model, subcellular calcium regulatory mechanisms are
3902            described in detail. There are six calcium fluxes to consider;
3903            J_rel, J_leak, J_up, J_tr, J_xfer and J_trpn. In addition, three
3904            membrane current fluxes are also necessary for the formulation of
3905            calcium regulation; i_p_Ca, i_Ca_L_Ca and i_NaCa.
3906          </rdf:value>
3907        </cmeta:comment>
3908      </rdf:Description>
3909    </rdf:RDF>
3910
3911    <!-- These variables are defined here and used in other components. -->
3912    <variable
3913        name="Cai" public_interface="out"
3914        initial_value="9.94893e-11" units="mM" />
3915    <variable
3916        name="Ca_SS" public_interface="out"
3917        initial_value="1.36058e-4" units="mM" />
3918    <variable
3919        name="Am" public_interface="out"
3920        initial_value="546.69" units="per_mm" />
3921    <variable
3922        name="V_myo" public_interface="out"
3923        initial_value="0.92" units="dimensionless" />
3924    
3925    <!-- These variables are defined here and only used internally. -->
3926    <variable name="RyR_open" units="dimensionless" />
3927    <variable name="P_O1" initial_value="1.19168e-3" units="dimensionless" />
3928    <variable name="P_O2" initial_value="6.30613e-9" units="dimensionless" />
3929    <variable name="P_C1" initial_value="0.762527" units="dimensionless" />
3930    <variable name="P_C2" initial_value="0.236283" units="dimensionless" />
3931    <variable name="v1" initial_value="1.8" units="per_ms" />
3932    <variable name="v2" initial_value="0.58e-4" units="per_ms" />
3933    <variable name="v3" initial_value="1.8e-3" units="mM_per_ms" />
3934    <variable name="nCa" initial_value="4.0" units="dimensionless" />
3935    <variable name="mCa" initial_value="3.0" units="dimensionless" />
3936    <variable name="k_a_plus" initial_value="1.215e10" units="per_mM4_per_ms" />
3937    <variable name="k_a_minus" initial_value="0.1425" units="per_ms" />
3938    <variable name="k_b_plus" initial_value="4.05e7" units="per_mM3_per_ms" />
3939    <variable name="k_b_minus" initial_value="1.930" units="per_ms" />
3940    <variable name="k_c_plus" initial_value="0.018" units="per_ms" />
3941    <variable name="k_c_minus" initial_value="0.0008" units="per_ms" />
3942    <variable name="k_htrpn_plus" initial_value="20.0" units="per_mM_per_ms" />
3943    <variable name="k_htrpn_minus" initial_value="0.066e-3" units="per_ms" />
3944    <variable name="k_ltrpn_plus" initial_value="40.0" units="per_mM_per_ms" />
3945    <variable name="k_ltrpn_minus" initial_value="0.04" units="per_ms" />
3946    <variable name="tau_tr" initial_value="34.48" units="ms" />
3947    <variable name="Ca_JSR" initial_value="1.17504" units="mM" />
3948    <variable name="Ca_NSR" initial_value="1.243891" units="mM" />
3949    <variable name="V_JSR" units="dimensionless" />
3950    <variable name="V_NSR" units="dimensionless" />
3951    <variable name="V_SS" units="dimensionless" />
3952    <variable name="K_mup" initial_value="0.5e-3" units="mM" />
3953    <variable name="K_mCMDN" initial_value="2.38e-3" units="mM" />
3954    <variable name="K_mCSQN" initial_value="0.8" units="mM" />
3955    <variable name="tau_xfer" initial_value="3.125" units="ms" />
3956    <variable name="HTRPN_tot" initial_value="0.14" units="mM" />
3957    <variable name="LTRPN_tot" initial_value="0.07" units="mM" />
3958    <variable name="HTRPNCa" initial_value="0.13598" units="mM" />
3959    <variable name="LTRPNCa" initial_value="0.00635" units="mM" />
3960    <variable name="CSQN_tot" initial_value="15.0" units="mM" />
3961    <variable name="CMDN_tot" initial_value="0.05" units="mM" />
3962    <variable name="Bi" units="dimensionless" />
3963    <variable name="B_SS" units="dimensionless" />
3964    <variable name="B_JSR" units="dimensionless" />
3965    <variable name="J_rel" units="mM_per_ms" />
3966    <variable name="J_leak" units="mM_per_ms" />
3967    <variable name="J_up" units="mM_per_ms" />
3968    <variable name="J_tr" units="mM_per_ms" />
3969    <variable name="J_xfer" units="mM_per_ms" />
3970    <variable name="J_trpn" units="mM_per_ms" />
3971    <variable name="J_htrpn" units="mM_per_ms" />
3972    <variable name="J_ltrpn" units="mM_per_ms" />
3973    
3974    <!-- These variables are imported from other components. -->
3975    <variable name="time" public_interface="in" units="ms" />
3976    <variable name="F" public_interface="in" units="faradays_constant_units" />
3977    <variable name="i_Ca_b" public_interface="in" units="uA_per_mm2" />
3978    <variable name="i_Ca_L_Ca" public_interface="in" units="uA_per_mm2" />
3979    <variable name="i_NaCa" public_interface="in" units="uA_per_mm2" />
3980    <variable name="i_p_Ca" public_interface="in" units="uA_per_mm2" />
3981    
3982    <rdf:RDF
3983      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
3984      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
3985      <rdf:Description rdf:about="#V_SS_calculation_eq">
3986        <cmeta:comment rdf:parseType="Resource">
3987          <rdf:value>
3988            Calculate some volume fractions as proportions of the total
3989            myoplasmic volume.
3990          </rdf:value>
3991        </cmeta:comment>
3992      </rdf:Description>
3993    </rdf:RDF>
3994    <math xmlns="http://www.w3.org/1998/Math/MathML"
3995      cmeta:id="V_SS_calculation_eq">
3996      <apply id="V_SS_calculation"><eq/>
3997        <ci>V_SS</ci>
3998        <apply><times/>
3999          <cn cellml:units="dimensionless">5.828e-5</cn>
4000          <ci>V_myo</ci>
4001        </apply>
4002      </apply>
4003    </math>
4004    <math xmlns="http://www.w3.org/1998/Math/MathML"
4005      cmeta:id="V_NSR_calculation_eq">
4006      <apply id="V_NSR_calculation"><eq/>
4007        <ci>V_NSR</ci>
4008        <apply><times/>
4009          <cn cellml:units="dimensionless">0.081</cn>
4010          <ci>V_myo</ci>
4011        </apply>
4012      </apply>
4013    </math>
4014    <math xmlns="http://www.w3.org/1998/Math/MathML"
4015      cmeta:id="V_JSR_calculation_eq">
4016      <apply id="V_JSR_calculation"><eq/>
4017        <ci>V_JSR</ci>
4018        <apply><times/>
4019          <cn cellml:units="dimensionless">0.00464</cn>
4020          <ci>V_myo</ci>
4021        </apply>
4022      </apply>
4023    </math>
4024      
4025    <rdf:RDF
4026      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4027      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4028      <rdf:Description rdf:about="#J_rel_calculation_eq">
4029        <cmeta:comment rdf:parseType="Resource">
4030          <rdf:value>
4031            The calcium release flux from the JSR into the restricted subspace
4032            is governed by the fraction of RyR channels in an open state.
4033          </rdf:value>
4034        </cmeta:comment>
4035      </rdf:Description>
4036    </rdf:RDF>
4037    <math xmlns="http://www.w3.org/1998/Math/MathML"
4038      cmeta:id="J_rel_calculation_eq">
4039      <apply id="J_rel_calculation"><eq />
4040        <ci> J_rel </ci>
4041        <apply><times />
4042          <ci> v1 </ci>
4043          <ci> RyR_open </ci>
4044          <apply><minus />
4045            <ci> Ca_JSR </ci>
4046            <ci> Ca_SS </ci>
4047          </apply>
4048        </apply>
4049      </apply>
4050    </math>
4051      
4052    <rdf:RDF
4053      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4054      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4055      <rdf:Description rdf:about="#RyR_open_calculation_eq">
4056        <cmeta:comment rdf:parseType="Resource">
4057          <rdf:value>
4058            The "open" RyR's are those P_O1 and P_O2 states.
4059          </rdf:value>
4060        </cmeta:comment>
4061      </rdf:Description>
4062    </rdf:RDF>
4063    <math xmlns="http://www.w3.org/1998/Math/MathML"
4064      cmeta:id="RyR_open_calculation_eq">
4065      <apply id="RyR_open_calculation"><eq />
4066        <ci> RyR_open </ci>
4067        <apply><plus />
4068          <ci> P_O1 </ci>
4069          <ci> P_O2 </ci>
4070        </apply>
4071      </apply>
4072    </math>
4073      
4074    <rdf:RDF
4075      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4076      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4077      <rdf:Description rdf:about="#P_C1_diff_eq">
4078        <cmeta:comment rdf:parseType="Resource">
4079          <rdf:value>
4080            The kinetic equations governing the transitions between the four
4081            states used to model the RyR's.
4082          </rdf:value>
4083        </cmeta:comment>
4084      </rdf:Description>
4085    </rdf:RDF>
4086    <math xmlns="http://www.w3.org/1998/Math/MathML"
4087      cmeta:id="P_C1_diff_eq">
4088      <apply id="P_C1_diff_eq"><eq />
4089        <apply><diff />
4090          <bvar><ci> time </ci></bvar>
4091          <ci> P_C1 </ci>
4092        </apply>
4093        <apply><plus />
4094          <apply><times />
4095            <apply><minus />
4096              <ci> k_a_plus </ci>
4097            </apply>
4098            <apply><power />
4099              <ci> Ca_SS </ci>
4100              <ci> nCa </ci>
4101            </apply>
4102            <ci> P_C1 </ci>
4103          </apply>
4104          <apply><times />
4105            <ci> k_a_minus </ci>
4106            <ci> P_O1 </ci>
4107          </apply>
4108        </apply>
4109      </apply>
4110    </math>
4111    <math xmlns="http://www.w3.org/1998/Math/MathML"
4112      cmeta:id="P_O1_diff_eq">
4113      <apply id="P_O1_diff_eq"><eq />
4114        <apply><diff />
4115          <bvar><ci> time </ci></bvar>
4116          <ci> P_O1 </ci>
4117        </apply>
4118        <apply><plus />
4119          <apply><minus />
4120            <apply><times />
4121              <ci> k_a_plus </ci>
4122              <apply><power />
4123                <ci> Ca_SS </ci>
4124                <ci> nCa </ci>
4125              </apply>
4126              <ci> P_C1 </ci>
4127            </apply>
4128            <apply><plus />
4129              <apply><times />
4130                <ci> k_a_minus </ci>
4131                <ci> P_O1 </ci>
4132              </apply>
4133              <apply><times />
4134                <ci> k_b_plus </ci>
4135                <apply><power />
4136                  <ci> Ca_SS </ci>
4137                  <ci> mCa </ci>
4138                </apply>
4139                <ci> P_O1 </ci>
4140              </apply>
4141              <apply><times />
4142                <ci> k_c_plus </ci>
4143                <ci> P_O1 </ci>
4144              </apply>
4145            </apply>
4146          </apply>
4147          <apply><times />
4148            <ci> k_b_minus </ci>
4149            <ci> P_O2 </ci>
4150          </apply>
4151          <apply><times />
4152            <ci> k_c_minus </ci>
4153            <ci> P_C2 </ci>
4154          </apply>
4155        </apply>
4156      </apply>
4157    </math>
4158    <math xmlns="http://www.w3.org/1998/Math/MathML"
4159      cmeta:id="P_O2_diff_eq">
4160      <apply id="P_O2_diff_eq"><eq />
4161        <apply><diff />
4162          <bvar><ci> time </ci></bvar>
4163          <ci> P_O2 </ci>
4164        </apply>
4165        <apply><minus />
4166          <apply><times />
4167            <ci> k_b_plus </ci>
4168            <apply><power />
4169              <ci> Ca_SS </ci>
4170              <ci> mCa </ci>
4171            </apply>
4172            <ci> P_O1 </ci>
4173          </apply>
4174          <apply><times />
4175            <ci> k_b_minus </ci>
4176            <ci> P_O2 </ci>
4177          </apply>
4178        </apply>
4179      </apply>
4180    </math>
4181    <math xmlns="http://www.w3.org/1998/Math/MathML"
4182      cmeta:id="P_C2_diff_eq">
4183      <apply id="P_C2_diff_eq"><eq />
4184        <apply><diff />
4185          <bvar><ci> time </ci></bvar>
4186          <ci> P_C2 </ci>
4187        </apply>
4188        <apply><minus />
4189          <apply><times />
4190            <ci> k_c_plus </ci>
4191            <ci> P_O1 </ci>
4192          </apply>
4193          <apply><times />
4194            <ci> k_c_minus </ci>
4195            <ci> P_C2 </ci>
4196          </apply>
4197        </apply>
4198      </apply>
4199    </math>
4200      
4201    <rdf:RDF
4202      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4203      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4204      <rdf:Description rdf:about="#J_leak_calculation_eq">
4205        <cmeta:comment rdf:parseType="Resource">
4206          <rdf:value>
4207            Calculate the leakage flux from the NSR into the myoplasm.
4208          </rdf:value>
4209        </cmeta:comment>
4210      </rdf:Description>
4211    </rdf:RDF>
4212    <math xmlns="http://www.w3.org/1998/Math/MathML"
4213      cmeta:id="J_leak_calculation_eq">
4214      <apply id="J_leak_calculation"><eq />
4215        <ci> J_leak </ci>
4216        <apply><times />
4217          <ci> v2 </ci>
4218          <apply><minus />
4219            <ci> Ca_NSR </ci>
4220            <ci> Cai </ci>
4221          </apply>
4222        </apply>
4223      </apply>
4224    </math>
4225      
4226    <rdf:RDF
4227      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4228      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4229      <rdf:Description rdf:about="#J_up_calculation_eq">
4230        <cmeta:comment rdf:parseType="Resource">
4231          <rdf:value>
4232            Calculate the uptake flux into the NSR from the myoplasm.
4233          </rdf:value>
4234        </cmeta:comment>
4235      </rdf:Description>
4236    </rdf:RDF>
4237    <math xmlns="http://www.w3.org/1998/Math/MathML"
4238      cmeta:id="J_up_calculation_eq">
4239      <apply id="J_up_calculation"><eq />
4240        <ci> J_up </ci>
4241        <apply><times />
4242          <ci> v3 </ci>
4243          <apply><divide />
4244            <apply><power />
4245              <ci> Cai </ci>
4246              <cn cellml:units="dimensionless"> 2.0 </cn>
4247            </apply>
4248            <apply><plus />
4249              <apply><power />
4250                <ci> K_mup </ci>
4251                <cn cellml:units="dimensionless"> 2.0 </cn>
4252              </apply>
4253              <apply><power />
4254                <ci> Cai </ci>
4255                <cn cellml:units="dimensionless"> 2.0 </cn>
4256              </apply>
4257            </apply>
4258          </apply>
4259        </apply>
4260      </apply>
4261    </math>
4262      
4263    <rdf:RDF
4264      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4265      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4266      <rdf:Description rdf:about="#J_tr_calculation_eq">
4267        <cmeta:comment rdf:parseType="Resource">
4268          <rdf:value>
4269            Calculate the translocation flux between the uptake (NSR) and
4270            release (JSR) stores.
4271          </rdf:value>
4272        </cmeta:comment>
4273      </rdf:Description>
4274    </rdf:RDF>
4275    <math xmlns="http://www.w3.org/1998/Math/MathML"
4276      cmeta:id="J_tr_calculation_eq">
4277      <apply id="J_tr_calculation"><eq />
4278        <ci> J_tr </ci>
4279        <apply><divide />
4280          <apply><minus />
4281            <ci> Ca_NSR </ci>
4282            <ci> Ca_JSR </ci>
4283          </apply>
4284          <ci> tau_tr </ci>
4285        </apply>
4286      </apply>
4287    </math>
4288      
4289    <rdf:RDF
4290      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4291      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4292      <rdf:Description rdf:about="#J_xfer_calculation_eq">
4293        <cmeta:comment rdf:parseType="Resource">
4294          <rdf:value>
4295            Calculate the calcium flux from the diffusion of calcium out of the
4296            restricted subspace into the myoplasm.
4297          </rdf:value>
4298        </cmeta:comment>
4299      </rdf:Description>
4300    </rdf:RDF>
4301    <math xmlns="http://www.w3.org/1998/Math/MathML"
4302      cmeta:id="J_xfer_calculation_eq">
4303      <apply id="J_xfer_calculation"><eq />
4304        <ci> J_xfer </ci>
4305        <apply><divide />
4306          <apply><minus />
4307            <ci> Ca_SS </ci>
4308            <ci> Cai </ci>
4309          </apply>
4310          <ci> tau_xfer </ci>
4311        </apply>
4312      </apply>
4313    </math>
4314      
4315    <rdf:RDF
4316      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4317      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4318      <rdf:Description rdf:about="#J_htrpn_calculation_eq">
4319        <cmeta:comment rdf:parseType="Resource">
4320          <rdf:value>
4321            The kinetics of calcium binding to the myoplasm buffer troponin -
4322            both high and low affinity binding sites.
4323          </rdf:value>
4324        </cmeta:comment>
4325      </rdf:Description>
4326    </rdf:RDF>
4327    <math xmlns="http://www.w3.org/1998/Math/MathML"
4328      cmeta:id="J_htrpn_calculation_eq">
4329      <apply id="J_htrpn_calculation"><eq />
4330        <ci> J_htrpn </ci>
4331        <apply><minus/>
4332          <apply><times />
4333            <ci> k_htrpn_plus </ci>
4334            <ci> Cai </ci>
4335            <apply><minus />
4336              <ci> HTRPN_tot </ci>
4337              <ci> HTRPNCa </ci>
4338            </apply>
4339          </apply>
4340          <apply><times />
4341            <ci> k_htrpn_minus </ci>
4342            <ci> HTRPNCa </ci>
4343          </apply>
4344        </apply>
4345      </apply>
4346    </math>
4347    <math xmlns="http://www.w3.org/1998/Math/MathML"
4348      cmeta:id="J_ltrpn_calculation_eq">
4349      <apply id="J_ltrpn_calculation"><eq />
4350        <ci> J_ltrpn </ci>
4351        <apply><minus/>
4352          <apply><times />
4353            <ci> k_ltrpn_plus </ci>
4354            <ci> Cai </ci>
4355            <apply><minus />
4356              <ci> LTRPN_tot </ci>
4357              <ci> LTRPNCa </ci>
4358            </apply>
4359          </apply>
4360          <apply><times />
4361            <ci> k_ltrpn_minus </ci>
4362            <ci> LTRPNCa </ci>
4363          </apply>
4364        </apply>
4365      </apply>
4366    </math>
4367    <math xmlns="http://www.w3.org/1998/Math/MathML"
4368      cmeta:id="J_trpn_calculation_eq">
4369      <apply id="J_trpn_calculation"><eq />
4370        <ci> J_trpn </ci>
4371        <apply><plus />
4372          <ci>J_htrpn</ci>
4373          <ci>J_ltrpn</ci>
4374        </apply>
4375      </apply>
4376    </math>
4377      
4378    <rdf:RDF
4379      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4380      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4381      <rdf:Description rdf:about="#HTRPNCa_diff_eq">
4382        <cmeta:comment rdf:parseType="Resource">
4383          <rdf:value>
4384            Keep track of the concentration of calcium ions bound to high and
4385            low affinity troponin binding sites.
4386          </rdf:value>
4387        </cmeta:comment>
4388      </rdf:Description>
4389    </rdf:RDF>
4390    <math xmlns="http://www.w3.org/1998/Math/MathML"
4391      cmeta:id="HTRPNCa_diff_eq">
4392      <apply id="HTRPNCa_diff_eq"><eq />
4393        <apply><diff />
4394          <bvar><ci> time </ci></bvar>
4395          <ci> HTRPNCa </ci>
4396        </apply>
4397        <ci>J_htrpn</ci>
4398      </apply>
4399    </math>
4400    <math xmlns="http://www.w3.org/1998/Math/MathML"
4401      cmeta:id="LTRPNCa_diff_eq">
4402      <apply id="LTRPNCa_diff_eq"><eq />
4403        <apply><diff />
4404          <bvar><ci> time </ci></bvar>
4405          <ci> LTRPNCa </ci>
4406        </apply>
4407        <ci>J_ltrpn</ci>
4408      </apply>
4409    </math>
4410      
4411    <rdf:RDF
4412      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4413      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4414      <rdf:Description rdf:about="#Bi_calculation_eq">
4415        <cmeta:comment rdf:parseType="Resource">
4416          <rdf:value>
4417            Calcium is buffered by calmodulin (CMDN) in the subspace and
4418            myoplasm, and by calsequestrin (CSQN) in the JSR. These are fast
4419            buffers and their effect is modelled using the rapid buffering
4420            approximation.
4421          </rdf:value>
4422        </cmeta:comment>
4423      </rdf:Description>
4424    </rdf:RDF>
4425    <math xmlns="http://www.w3.org/1998/Math/MathML"
4426      cmeta:id="Bi_calculation_eq">
4427      <apply id="Bi_calculation"><eq />
4428        <ci> Bi </ci>
4429        <apply><divide />
4430          <cn cellml:units="dimensionless"> 1.0 </cn>
4431          <apply><plus />
4432            <cn cellml:units="dimensionless"> 1.0 </cn>
4433            <apply><divide />
4434              <apply><times />
4435                <ci> CMDN_tot </ci>
4436                <ci> K_mCMDN </ci>
4437              </apply>
4438              <apply><power />
4439                <apply><plus />
4440                  <ci> K_mCMDN </ci>
4441                  <ci> Cai </ci>
4442                </apply>
4443                <cn cellml:units="dimensionless"> 2.0 </cn>
4444              </apply>
4445            </apply>
4446          </apply>
4447        </apply>
4448      </apply>
4449    </math>
4450    <math xmlns="http://www.w3.org/1998/Math/MathML"
4451      cmeta:id="B_SS_calculation_eq">
4452      <apply id="B_SS_calculation"><eq />
4453        <ci> B_SS </ci>
4454        <apply><divide />
4455          <cn cellml:units="dimensionless"> 1.0 </cn>
4456          <apply><plus />
4457            <cn cellml:units="dimensionless"> 1.0 </cn>
4458            <apply><divide />
4459              <apply><times />
4460                <ci> CMDN_tot </ci>
4461                <ci> K_mCMDN </ci>
4462              </apply>
4463              <apply><power />
4464                <apply><plus />
4465                  <ci> K_mCMDN </ci>
4466                  <ci> Ca_SS </ci>
4467                </apply>
4468                <cn cellml:units="dimensionless"> 2.0 </cn>
4469              </apply>
4470            </apply>
4471          </apply>
4472        </apply>
4473      </apply>
4474    </math>
4475    <math xmlns="http://www.w3.org/1998/Math/MathML"
4476      cmeta:id="B_JSR_calculation_eq">
4477      <apply id="B_JSR_calculation"><eq />
4478        <ci> B_JSR </ci>
4479        <apply><divide />
4480          <cn cellml:units="dimensionless"> 1.0 </cn>
4481          <apply><plus />
4482            <cn cellml:units="dimensionless"> 1.0 </cn>
4483            <apply><divide />
4484              <apply><times />
4485                <ci> CSQN_tot </ci>
4486                <ci> K_mCSQN </ci>
4487              </apply>
4488              <apply><power />
4489                <apply><plus />
4490                  <ci> K_mCSQN </ci>
4491                  <ci> Ca_JSR </ci>
4492                </apply>
4493                <cn cellml:units="dimensionless"> 2.0 </cn>
4494              </apply>
4495            </apply>
4496          </apply>
4497        </apply>
4498      </apply>
4499    </math>
4500      
4501    <rdf:RDF
4502      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4503      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4504      <rdf:Description rdf:about="#calcium_internal_diff_eq">
4505        <cmeta:comment rdf:parseType="Resource">
4506          <rdf:value>
4507            The kinetics of the calcium ion concentration changes in the various
4508            compartments of the model.
4509          </rdf:value>
4510        </cmeta:comment>
4511      </rdf:Description>
4512    </rdf:RDF>
4513    <math xmlns="http://www.w3.org/1998/Math/MathML"
4514      cmeta:id="calcium_internal_diff_eq">
4515      <apply id="calcium_internal_diff_eq"><eq />
4516        <apply><diff />
4517          <bvar><ci> time </ci></bvar>
4518          <ci> Cai </ci>
4519        </apply>
4520        <apply><times />
4521          <ci> Bi </ci>
4522          <apply><minus />
4523            <apply><plus />
4524              <ci> J_leak </ci>
4525              <ci> J_xfer </ci>
4526            </apply>
4527            <apply><plus />
4528              <ci> J_up </ci>
4529              <ci> J_trpn </ci>
4530              <apply><times />
4531                <apply><plus />
4532                  <apply><minus />
4533                    <ci> i_Ca_b </ci>
4534                    <apply><times />
4535                      <cn cellml:units="dimensionless"> 2.0 </cn>
4536                      <ci> i_NaCa </ci>
4537                    </apply>
4538                  </apply>
4539                  <ci> i_p_Ca </ci>
4540                </apply>
4541                <apply><divide />
4542                  <ci> Am </ci>
4543                  <apply><times />
4544                    <cn cellml:units="dimensionless"> 2.0 </cn>
4545                    <ci> V_myo </ci>
4546                    <ci> F </ci>
4547                  </apply>
4548                </apply>
4549              </apply>
4550            </apply>
4551          </apply>
4552        </apply>
4553      </apply>
4554    </math>
4555    <math xmlns="http://www.w3.org/1998/Math/MathML"
4556      cmeta:id="calcium_subspace_diff_eq">
4557      <apply id="calcium_subspace_diff_eq"><eq />
4558        <apply><diff />
4559          <bvar><ci> time </ci></bvar>
4560          <ci> Ca_SS </ci>
4561        </apply>
4562        <apply><times />
4563          <ci> B_SS </ci>
4564          <apply><minus />
4565            <apply><minus />
4566              <apply><times />
4567                <ci> J_rel </ci>
4568                <apply><divide />
4569                  <ci> V_JSR </ci>
4570                  <ci> V_SS </ci>
4571                </apply>
4572              </apply>
4573              <apply><times />
4574                <ci> J_xfer </ci>
4575                <apply><divide />
4576                  <ci> V_myo </ci>
4577                  <ci> V_SS </ci>
4578                </apply>
4579              </apply>
4580            </apply>
4581            <apply><times />
4582              <ci> i_Ca_L_Ca </ci>
4583              <apply><divide />
4584                <ci> Am </ci>
4585                <apply><times />
4586                  <cn cellml:units="dimensionless"> 2.0 </cn>
4587                  <ci> V_SS </ci>
4588                  <ci> F </ci>
4589                </apply>
4590              </apply>
4591            </apply>
4592          </apply>
4593        </apply>
4594      </apply>
4595    </math>
4596    <math xmlns="http://www.w3.org/1998/Math/MathML"
4597      cmeta:id="calcium_JSR_diff_eq">
4598      <apply id="calcium_JSR_diff_eq"><eq />
4599        <apply><diff />
4600          <bvar><ci> time </ci></bvar>
4601          <ci> Ca_JSR </ci>
4602        </apply>
4603        <apply><times />
4604          <ci> B_JSR </ci>
4605          <apply><minus />
4606            <ci> J_tr </ci>
4607            <ci> J_rel </ci>
4608          </apply>
4609        </apply>
4610      </apply>
4611    </math>
4612    <math xmlns="http://www.w3.org/1998/Math/MathML"
4613      cmeta:id="calcium_NSR_diff_eq">
4614      <apply id="calcium_NSR_diff_eq"><eq />
4615        <apply><diff />
4616          <bvar><ci> time </ci></bvar>
4617          <ci> Ca_NSR </ci>
4618        </apply>
4619        <apply><minus />
4620          <apply><times />
4621            <apply><minus />
4622              <ci> J_up </ci>
4623              <ci> J_leak </ci>
4624            </apply>
4625            <apply><divide />
4626              <ci> V_myo </ci>
4627              <ci> V_NSR </ci>
4628            </apply>
4629          </apply>
4630          <apply><times />
4631            <ci> J_tr </ci>
4632            <apply><divide />
4633              <ci> V_JSR </ci>
4634              <ci> V_NSR </ci>
4635            </apply>
4636          </apply>
4637        </apply>
4638      </apply>
4639    </math>
4640  </component>
4641  
4642  <!--
4643    The descriptions of the rate of change of [Na]i and [K]i are the same as the
4644    LR-II model.  In addition to the LR-II model, both high and low affinity    
4645    calcium binding sites are included for troponin (Tn).
4646  -->
4647  <component name="ionic_concentrations" cmeta:id="ionic_concentrations">
4648    <rdf:RDF
4649      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4650      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4651      <rdf:Description rdf:about="#ionic_concentrations">
4652        <cmeta:comment rdf:parseType="Resource">
4653          <rdf:value>
4654            The descriptions of the rate of change of [Na]i and [K]i are the
4655            same as the LR-II model.
4656          </rdf:value>
4657        </cmeta:comment>
4658      </rdf:Description>
4659    </rdf:RDF>
4660
4661    <!-- these variables are defined here and used in other components -->
4662    <variable
4663        name="Nai" public_interface="out"
4664        initial_value="10.2042" units="mM" />
4665    <variable
4666        name="Nao" public_interface="out"
4667        initial_value="140.0" units="mM" />
4668    <variable
4669        name="Ki" public_interface="out"
4670        initial_value="143.727" units="mM" />
4671    <variable
4672        name="Ko" public_interface="out"
4673        initial_value="5.4" units="mM" />
4674    <variable
4675        name="Cao" public_interface="out"
4676        initial_value="1.8" units="mM" />
4677    
4678    <!-- These variables are imported from other components. -->
4679    <variable name="time" public_interface="in" units="ms" />
4680    <variable name="F" public_interface="in" units="faradays_constant_units" />
4681    <variable name="i_Na" public_interface="in" units="uA_per_mm2" />
4682    <variable name="i_Na_b" public_interface="in" units="uA_per_mm2" />
4683    <variable name="i_ns_Na" public_interface="in" units="uA_per_mm2" />
4684    <variable name="i_NaCa" public_interface="in" units="uA_per_mm2" />
4685    <variable name="i_NaK" public_interface="in" units="uA_per_mm2" />
4686    <variable name="i_Ca_L_K" public_interface="in" units="uA_per_mm2" />
4687    <variable name="i_K" public_interface="in" units="uA_per_mm2" />
4688    <variable name="i_K1" public_interface="in" units="uA_per_mm2" />
4689    <variable name="i_Kp" public_interface="in" units="uA_per_mm2" />
4690    <variable name="i_ns_K" public_interface="in" units="uA_per_mm2" />
4691    <variable name="Am" public_interface="in" units="per_mm" />
4692    <variable name="V_myo" public_interface="in" units="dimensionless" />
4693    
4694    <rdf:RDF
4695      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4696      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4697      <rdf:Description rdf:about="#sodium_diff_eq">
4698        <cmeta:comment rdf:parseType="Resource">
4699          <rdf:value>
4700            The rate of change of intracellular sodium ion concentration.
4701          </rdf:value>
4702        </cmeta:comment>
4703      </rdf:Description>
4704    </rdf:RDF>
4705    <math xmlns="http://www.w3.org/1998/Math/MathML" cmeta:id="sodium_diff_eq">
4706      <apply id="sodium_diff_eq"><eq />
4707        <apply><diff />
4708          <bvar><ci> time </ci></bvar>
4709          <ci> Nai </ci>
4710        </apply>
4711        <apply><times />
4712          <apply><minus />
4713            <apply><plus />
4714              <ci> i_Na </ci>
4715              <ci> i_Na_b </ci>
4716              <ci> i_ns_Na </ci>
4717              <apply><times />
4718                <ci> i_NaCa </ci>
4719                <cn cellml:units="dimensionless"> 3.0 </cn>
4720              </apply>
4721              <apply><times />
4722                <ci> i_NaK </ci>
4723                <cn cellml:units="dimensionless"> 3.0 </cn>
4724              </apply>
4725            </apply>
4726          </apply>
4727          <apply><divide />
4728            <ci> Am </ci>
4729            <apply><times />
4730              <ci> V_myo </ci>
4731              <ci> F </ci>
4732            </apply>
4733          </apply>
4734        </apply>
4735      </apply>
4736    </math>
4737      
4738    <rdf:RDF
4739      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4740      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4741      <rdf:Description rdf:about="#potassium_internal_diff_eq">
4742        <cmeta:comment rdf:parseType="Resource">
4743          <rdf:value>
4744            The rate of change of intracellular potassium ion concentration.
4745          </rdf:value>
4746        </cmeta:comment>
4747      </rdf:Description>
4748    </rdf:RDF>
4749    <math xmlns="http://www.w3.org/1998/Math/MathML"
4750      cmeta:id="potassium_internal_diff_eq">
4751      <apply id="potassium_internal_diff_eq"><eq />
4752        <apply><diff />
4753          <bvar><ci> time </ci></bvar>
4754          <ci> Ki </ci>
4755        </apply>
4756        <apply><times />
4757          <apply><minus />
4758            <apply><plus />
4759              <ci> i_Ca_L_K </ci>
4760              <ci> i_K </ci>
4761              <ci> i_K1 </ci>
4762              <ci> i_Kp </ci>
4763              <ci> i_ns_K </ci>
4764              <apply><minus />
4765                <apply><times />
4766                  <ci> i_NaK </ci>
4767                  <cn cellml:units="dimensionless"> 2.0 </cn>
4768                </apply>
4769              </apply>
4770            </apply>
4771          </apply>
4772          <apply><divide />
4773            <ci> Am </ci>
4774            <apply><times />
4775              <ci> V_myo </ci>
4776              <ci> F </ci>
4777            </apply>
4778          </apply>
4779        </apply>        
4780      </apply>
4781    </math>
4782      
4783    <rdf:RDF
4784      xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
4785      xmlns:cmeta="http://www.cellml.org/metadata/1.0#">
4786      <rdf:Description rdf:about="#potassium_external_diff_eq">
4787        <cmeta:comment rdf:parseType="Resource">
4788          <rdf:value>
4789            The rate of change of extracellular potassium ion concentration.
4790          </rdf:value>
4791        </cmeta:comment>
4792      </rdf:Description>
4793    </rdf:RDF>
4794    <math xmlns="http://www.w3.org/1998/Math/MathML"
4795      cmeta:id="potassium_external_diff_eq">
4796      <apply id="potassium_external_diff_eq"><eq />
4797        <apply><diff />
4798          <bvar><ci> time </ci></bvar>
4799          <ci> Ko </ci>
4800        </apply>
4801        <apply><times />
4802          <apply><plus />
4803            <ci> i_Ca_L_K </ci>
4804            <ci> i_K </ci>
4805            <ci> i_K1 </ci>
4806            <ci> i_Kp </ci>
4807            <ci> i_ns_K </ci>
4808            <apply><minus />
4809              <apply><times />
4810                <ci> i_NaK </ci>
4811                <cn cellml:units="dimensionless"> 2.0 </cn>
4812              </apply>
4813            </apply>
4814          </apply>
4815          <apply><divide />
4816            <ci> Am </ci>
4817            <apply><times />
4818              <ci> V_myo </ci>
4819              <ci> F </ci>
4820            </apply>
4821          </apply>
4822        </apply>        
4823      </apply>
4824    </math>
4825  </component>
4826      
4827  <!--
4828    The following <group> element specifies a single containment hierarchy
4829    that encompasses all of the components in the model, with the exception of
4830    the "environment" component.  The "containment" relationship is used to     
4831    describe geometric hierarchies - or how components are physically arranged  
4832    in relation to eachother. 
4833  -->
4834  <group>
4835    <relationship_ref relationship="containment" />
4836    <component_ref component="membrane">
4837      <component_ref component="fast_sodium_current">
4838        <component_ref component="fast_sodium_current_m_gate" />
4839        <component_ref component="fast_sodium_current_h_gate" />
4840        <component_ref component="fast_sodium_current_j_gate" />
4841      </component_ref>
4842      <component_ref component="L_type_Ca_channel">
4843        <component_ref component="L_type_Ca_channel_y_gate" />
4844      </component_ref>
4845      <component_ref component="time_dependent_potassium_current">
4846        <component_ref component="time_dependent_potassium_current_X_gate" />
4847        <component_ref component="time_dependent_potassium_current_Xi_gate" />
4848      </component_ref>
4849      <component_ref component="Na_Ca_exchanger" />
4850      <component_ref component="time_independent_potassium_current">
4851        <component_ref component="time_independent_potassium_current_K1_gate" />
4852      </component_ref> 
4853      <component_ref component="plateau_potassium_current" />
4854      <component_ref component="sarcolemmal_calcium_pump" />
4855      <component_ref component="sodium_background_current" />
4856      <component_ref component="calcium_background_current" />
4857      <component_ref component="sodium_potassium_pump" />
4858      <component_ref component="non_specific_calcium_activated_current" />
4859      <component_ref component="calcium_subsystem" />
4860      <component_ref component="ionic_concentrations" />
4861    </component_ref>
4862  </group>
4863       
4864  <!--
4865    The following <group> element specifies how the components                  
4866    representing activation and inactivation coefficients are                   
4867    encapsulated inside the sodium and potassium channel components.            
4868    Encapsulation describes the logical hierarchy of components in a network,   
4869    and may or may not reflect their physical arrangement. 
4870  -->
4871  <group>
4872    <relationship_ref relationship="encapsulation" />
4873    <component_ref component="fast_sodium_current">
4874      <component_ref component="fast_sodium_current_m_gate" />
4875      <component_ref component="fast_sodium_current_h_gate" />
4876      <component_ref component="fast_sodium_current_j_gate" />
4877    </component_ref>
4878    <component_ref component="L_type_Ca_channel">
4879      <component_ref component="L_type_Ca_channel_y_gate" />
4880    </component_ref>
4881    <component_ref component="time_dependent_potassium_current">
4882      <component_ref component="time_dependent_potassium_current_X_gate" />
4883      <component_ref component="time_dependent_potassium_current_Xi_gate" />
4884    </component_ref>
4885    <component_ref component="time_independent_potassium_current">
4886      <component_ref component="time_independent_potassium_current_K1_gate" />
4887    </component_ref>
4888  </group>
4889  
4890  <!--
4891    "Time" is passed from the "environment" component into the
4892    "membrane" and current components.
4893  -->
4894  <connection>
4895    <map_components
4896        component_1="membrane" component_2="environment" />
4897    <map_variables variable_1="time" variable_2="time" />
4898  </connection>
4899
4900
4901  <connection>
4902    <map_components
4903        component_1="fast_sodium_current" component_2="environment" />
4904    <map_variables variable_1="time" variable_2="time" />
4905  </connection>
4906
4907
4908  <connection>
4909    <map_components
4910        component_1="L_type_Ca_channel" component_2="environment" />
4911    <map_variables variable_1="time" variable_2="time" />
4912  </connection>
4913  
4914  
4915  <connection>
4916    <map_components
4917        component_1="time_dependent_potassium_current" component_2="environment" />
4918    <map_variables variable_1="time" variable_2="time" />
4919  </connection>
4920  
4921  
4922  <connection>
4923    <map_components
4924        component_1="Na_Ca_exchanger" component_2="environment" />
4925    <map_variables variable_1="time" variable_2="time" />
4926  </connection>
4927  
4928  
4929  <connection>
4930    <map_components
4931        component_1="time_independent_potassium_current" component_2="environment" />
4932    <map_variables variable_1="time" variable_2="time" />
4933  </connection>
4934  
4935  
4936  <connection>
4937    <map_components
4938        component_1="plateau_potassium_current" component_2="environment" />
4939    <map_variables variable_1="time" variable_2="time" />
4940  </connection>
4941  
4942  
4943  <connection>
4944    <map_components
4945        component_1="sarcolemmal_calcium_pump" component_2="environment" />
4946    <map_variables variable_1="time" variable_2="time" />
4947  </connection>
4948  
4949  
4950  <connection>
4951    <map_components
4952        component_1="sodium_background_current" component_2="environment" />
4953    <map_variables variable_1="time" variable_2="time" />
4954  </connection>
4955  
4956  
4957  <connection>
4958    <map_components
4959        component_1="calcium_background_current" component_2="environment" />
4960    <map_variables variable_1="time" variable_2="time" />
4961  </connection>
4962  
4963  
4964  <connection>
4965    <map_components
4966        component_1="sodium_potassium_pump" component_2="environment" />
4967    <map_variables variable_1="time" variable_2="time" />
4968  </connection>
4969  
4970  
4971  <connection>
4972    <map_components
4973        component_1="non_specific_calcium_activated_current" component_2="environment" />
4974    <map_variables variable_1="time" variable_2="time" />
4975  </connection>
4976  
4977  
4978  <connection>
4979    <map_components
4980        component_1="calcium_subsystem" component_2="environment" />
4981    <map_variables variable_1="time" variable_2="time" />
4982  </connection>
4983  
4984  <connection>
4985    <map_components
4986        component_1="ionic_concentrations" component_2="environment" />
4987    <map_variables variable_1="time" variable_2="time" />
4988  </connection>
4989  
4990  <!--
4991    Several variables are passed between the "membrane" and its sub-components.
4992  -->
4993  
4994  <connection>
4995    <map_components
4996        component_1="membrane" component_2="fast_sodium_current" />
4997    <map_variables variable_1="V" variable_2="V" />
4998     <map_variables variable_1="i_Na" variable_2="i_Na" />
4999     <map_variables variable_1="R" variable_2="R" />
5000     <map_variables variable_1="T" variable_2="T" />
5001    <map_variables variable_1="F" variable_2="F" />
5002  </connection>
5003
5004
5005  <connection>
5006    <map_components
5007        component_1="membrane" component_2="L_type_Ca_channel" />
5008    <map_variables variable_1="V" variable_2="V" />
5009    <map_variables variable_1="i_Ca_L_Ca" variable_2="i_Ca_L_Ca" />
5010    <map_variables variable_1="i_Ca_L_K" variable_2="i_Ca_L_K" />
5011    <map_variables variable_1="R" variable_2="R" />
5012    <map_variables variable_1="T" variable_2="T" />
5013    <map_variables variable_1="F" variable_2="F" />
5014  </connection>
5015  
5016  
5017  <connection>
5018    <map_components
5019        component_1="membrane" component_2="time_dependent_potassium_current" />
5020    <map_variables variable_1="V" variable_2="V" />
5021    <map_variables variable_1="i_K" variable_2="i_K" />
5022    <map_variables variable_1="R" variable_2="R" />
5023    <map_variables variable_1="T" variable_2="T" />
5024    <map_variables variable_1="F" variable_2="F" />
5025  </connection>
5026  
5027  
5028  <connection>
5029    <map_components
5030        component_1="membrane" component_2="Na_Ca_exchanger" />
5031    <map_variables variable_1="V" variable_2="V" />
5032    <map_variables variable_1="i_NaCa" variable_2="i_NaCa" />
5033    <map_variables variable_1="R" variable_2="R" />
5034    <map_variables variable_1="T" variable_2="T" />
5035    <map_variables variable_1="F" variable_2="F" />
5036  </connection>
5037 
5038  
5039  <connection>
5040    <map_components
5041        component_1="membrane" component_2="time_independent_potassium_current" />
5042    <map_variables variable_1="V" variable_2="V" />
5043    <map_variables variable_1="i_K1" variable_2="i_K1" />
5044    <map_variables variable_1="R" variable_2="R" />
5045    <map_variables variable_1="T" variable_2="T" />
5046    <map_variables variable_1="F" variable_2="F" />
5047  </connection>
5048  
5049  
5050  <connection>
5051    <map_components
5052        component_1="membrane" component_2="plateau_potassium_current" />
5053    <map_variables variable_1="V" variable_2="V" />
5054     <map_variables variable_1="i_Kp" variable_2="i_Kp" />
5055  </connection>
5056
5057
5058  <connection>
5059    <map_components
5060        component_1="membrane" component_2="sarcolemmal_calcium_pump" />
5061    <map_variables variable_1="i_p_Ca" variable_2="i_p_Ca" />
5062  </connection>
5063  
5064  
5065  <connection>
5066    <map_components
5067        component_1="membrane" component_2="sodium_background_current" />
5068    <map_variables variable_1="V" variable_2="V" />
5069     <map_variables variable_1="i_Na_b" variable_2="i_Na_b" />
5070  </connection>
5071
5072
5073  <connection>
5074    <map_components
5075        component_1="membrane" component_2="calcium_background_current" />
5076    <map_variables variable_1="V" variable_2="V" />
5077    <map_variables variable_1="i_Ca_b" variable_2="i_Ca_b" />
5078    <map_variables variable_1="R" variable_2="R" />
5079    <map_variables variable_1="T" variable_2="T" />
5080    <map_variables variable_1="F" variable_2="F" />
5081  </connection>
5082  
5083  
5084  <connection>
5085    <map_components
5086        component_1="membrane" component_2="sodium_potassium_pump" />
5087    <map_variables variable_1="V" variable_2="V" />
5088    <map_variables variable_1="i_NaK" variable_2="i_NaK" />
5089    <map_variables variable_1="R" variable_2="R" />
5090    <map_variables variable_1="T" variable_2="T" />
5091    <map_variables variable_1="F" variable_2="F" />
5092  </connection>
5093  
5094  
5095  <connection>
5096    <map_components
5097        component_1="membrane" component_2="non_specific_calcium_activated_current" />
5098    <map_variables variable_1="V" variable_2="V" />
5099    <map_variables variable_1="i_ns_Ca" variable_2="i_ns_Ca" />
5100    <map_variables variable_1="R" variable_2="R" />
5101    <map_variables variable_1="T" variable_2="T" />
5102    <map_variables variable_1="F" variable_2="F" />
5103  </connection>
5104  
5105  
5106  <connection>
5107    <map_components
5108        component_1="membrane" component_2="calcium_subsystem" />
5109    <map_variables variable_1="F" variable_2="F" />
5110  </connection>
5111  
5112  
5113  <connection>
5114    <map_components
5115        component_1="membrane" component_2="ionic_concentrations" />
5116    <map_variables variable_1="F" variable_2="F" />
5117  </connection>
5118  
5119      
5120  <!--  Several variables are passed between the sibling components. -->
5121  
5122  <connection>
5123    <map_components
5124        component_1="fast_sodium_current" component_2="ionic_concentrations" />
5125    <map_variables variable_1="Nai" variable_2="Nai" />
5126    <map_variables variable_1="Nao" variable_2="Nao" />
5127    <map_variables variable_1="i_Na" variable_2="i_Na" />
5128  </connection>
5129  
5130  
5131  <connection>
5132    <map_components
5133        component_1="fast_sodium_current" component_2="sodium_background_current" />
5134    <map_variables variable_1="E_Na" variable_2="E_Na" />
5135  </connection>
5136  
5137  
5138  <connection>
5139    <map_components
5140        component_1="L_type_Ca_channel" component_2="calcium_subsystem" />
5141    <map_variables variable_1="Ca_SS" variable_2="Ca_SS" />
5142    <map_variables variable_1="i_Ca_L_Ca" variable_2="i_Ca_L_Ca" />
5143  </connection>
5144  
5145  
5146  <connection>
5147    <map_components
5148        component_1="L_type_Ca_channel" component_2="ionic_concentrations" />
5149    <map_variables variable_1="i_Ca_L_K" variable_2="i_Ca_L_K" />
5150    <map_variables variable_1="Ki" variable_2="Ki" />
5151    <map_variables variable_1="Ko" variable_2="Ko" />
5152    <map_variables variable_1="Cao" variable_2="Cao" />
5153  </connection>
5154  
5155  
5156  <connection>
5157    <map_components
5158        component_1="time_dependent_potassium_current" component_2="ionic_concentrations" />
5159    <map_variables variable_1="Ki" variable_2="Ki" />
5160    <map_variables variable_1="Ko" variable_2="Ko" />
5161    <map_variables variable_1="Nao" variable_2="Nao" />
5162    <map_variables variable_1="Nai" variable_2="Nai" />
5163    <map_variables variable_1="i_K" variable_2="i_K" />
5164  </connection>
5165  
5166  
5167  <connection>
5168    <map_components
5169        component_1="Na_Ca_exchanger" component_2="ionic_concentrations" />
5170    <map_variables variable_1="Cao" variable_2="Cao" />
5171    <map_variables variable_1="Nai" variable_2="Nai" />
5172    <map_variables variable_1="Nao" variable_2="Nao" />
5173    <map_variables variable_1="i_NaCa" variable_2="i_NaCa" />
5174  </connection>
5175  
5176  
5177  <connection>
5178    <map_components
5179        component_1="Na_Ca_exchanger" component_2="calcium_subsystem" />
5180    <map_variables variable_1="Cai" variable_2="Cai" />
5181    <map_variables variable_1="i_NaCa" variable_2="i_NaCa" />
5182  </connection>
5183  
5184  
5185  <connection>
5186    <map_components
5187        component_1="time_independent_potassium_current" component_2="ionic_concentrations" />
5188    <map_variables variable_1="Ki" variable_2="Ki" />
5189    <map_variables variable_1="Ko" variable_2="Ko" />
5190    <map_variables variable_1="i_K1" variable_2="i_K1" />
5191  </connection>
5192  
5193  
5194  <connection>
5195    <map_components
5196        component_1="plateau_potassium_current" component_2="time_independent_potassium_current" />
5197    <map_variables variable_1="E_K1" variable_2="E_K1" />
5198  </connection>
5199  
5200  
5201  <connection>
5202    <map_components
5203        component_1="plateau_potassium_current" component_2="ionic_concentrations" />
5204    <map_variables variable_1="i_Kp" variable_2="i_Kp" />
5205  </connection>
5206  
5207  <connection>
5208    <map_components
5209        component_1="sodium_background_current" component_2="ionic_concentrations" />
5210    <map_variables variable_1="i_Na_b" variable_2="i_Na_b" />
5211  </connection>
5212  
5213  
5214  <connection>
5215    <map_components
5216        component_1="sarcolemmal_calcium_pump" component_2="calcium_subsystem" />
5217    <map_variables variable_1="i_p_Ca" variable_2="i_p_Ca" />
5218    <map_variables variable_1="Cai" variable_2="Cai" />
5219  </connection>
5220  
5221  
5222  <connection>
5223    <map_components
5224        component_1="calcium_background_current" component_2="calcium_subsystem" />
5225    <map_variables variable_1="Cai" variable_2="Cai" />
5226    <map_variables variable_1="i_Ca_b" variable_2="i_Ca_b" />
5227  </connection>
5228  
5229  <connection>
5230    <map_components
5231        component_1="calcium_background_current" component_2="ionic_concentrations" />
5232    <map_variables variable_1="Cao" variable_2="Cao" />
5233  </connection>
5234  
5235  
5236  <connection>
5237    <map_components
5238        component_1="sodium_potassium_pump" component_2="ionic_concentrations" />
5239    <map_variables variable_1="Nai" variable_2="Nai" />
5240    <map_variables variable_1="Nao" variable_2="Nao" />
5241    <map_variables variable_1="Ko" variable_2="Ko" />
5242    <map_variables variable_1="i_NaK" variable_2="i_NaK" />
5243  </connection>
5244  
5245  
5246  <connection>
5247    <map_components
5248        component_1="non_specific_calcium_activated_current" component_2="ionic_concentrations" />
5249    <map_variables variable_1="i_ns_Na" variable_2="i_ns_Na" />
5250    <map_variables variable_1="i_ns_K" variable_2="i_ns_K" />
5251    <map_variables variable_1="Nai" variable_2="Nai" />
5252    <map_variables variable_1="Nao" variable_2="Nao" />
5253    <map_variables variable_1="Ko" variable_2="Ko" />
5254    <map_variables variable_1="Ki" variable_2="Ki" />
5255  </connection>
5256  
5257  
5258  <connection>
5259    <map_components
5260        component_1="non_specific_calcium_activated_current" component_2="calcium_subsystem" />
5261    <map_variables variable_1="Cai" variable_2="Cai" />
5262  </connection>
5263  
5264  <connection>
5265    <map_components
5266        component_1="ionic_concentrations" component_2="calcium_subsystem" />
5267    <map_variables variable_1="Am" variable_2="Am" />
5268    <map_variables variable_1="V_myo" variable_2="V_myo" />
5269  </connection>
5270  
5271  <!--  
5272    Various variables are passed between parent components and their            
5273    encapsulated gates.
5274  -->
5275  
5276  <connection>
5277    <map_components
5278        component_1="fast_sodium_current" component_2="fast_sodium_current_m_gate" />
5279    <map_variables variable_1="m" variable_2="m" />
5280    <map_variables variable_1="time" variable_2="time" />
5281    <map_variables variable_1="V" variable_2="V" />
5282  </connection>
5283  
5284  <connection>
5285    <map_components
5286        component_1="fast_sodium_current" component_2="fast_sodium_current_h_gate" />
5287    <map_variables variable_1="h" variable_2="h" />
5288    <map_variables variable_1="time" variable_2="time" />
5289    <map_variables variable_1="V" variable_2="V" />
5290  </connection>
5291  
5292  <connection>
5293    <map_components
5294        component_1="fast_sodium_current" component_2="fast_sodium_current_j_gate" />
5295    <map_variables variable_1="j" variable_2="j" />
5296    <map_variables variable_1="time" variable_2="time" />
5297    <map_variables variable_1="V" variable_2="V" />
5298  </connection>
5299  
5300  <connection>
5301    <map_components
5302        component_1="L_type_Ca_channel" component_2="L_type_Ca_channel_y_gate" />
5303    <map_variables variable_1="y" variable_2="y" />
5304    <map_variables variable_1="time" variable_2="time" />
5305    <map_variables variable_1="V" variable_2="V" />
5306  </connection>
5307  
5308  <connection>
5309    <map_components
5310        component_1="time_dependent_potassium_current" component_2="time_dependent_potassium_current_X_gate" />
5311    <map_variables variable_1="X" variable_2="X" />
5312    <map_variables variable_1="time" variable_2="time" />
5313    <map_variables variable_1="V" variable_2="V" />
5314  </connection>
5315  
5316  <connection>
5317    <map_components
5318        component_1="time_dependent_potassium_current" component_2="time_dependent_potassium_current_Xi_gate" />
5319    <map_variables variable_1="Xi" variable_2="Xi" />
5320    <map_variables variable_1="time" variable_2="time" />
5321    <map_variables variable_1="V" variable_2="V" />
5322  </connection>
5323  
5324  <connection>
5325    <map_components
5326        component_1="time_independent_potassium_current" component_2="time_independent_potassium_current_K1_gate" />
5327    <map_variables variable_1="time" variable_2="time" />
5328    <map_variables variable_1="V" variable_2="V" />
5329    <map_variables variable_1="E_K1" variable_2="E_K1" />
5330    <map_variables variable_1="K1_infinity" variable_2="K1_infinity" />
5331  </connection>
5332    
5333</model>