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an increasing rate constant, supposedly caused by microbial growth" />


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    <h1>Logistic kinetics</h1>
    <small class="dont-index">Source: <a href='https://github.com/jranke/mkin/blob/master/R/parent_solutions.R'><code>R/parent_solutions.R</code></a></small>
    <div class="hidden name"><code>logistic.solution.Rd</code></div>
    </div>

    <div class="ref-description">
    <p>Function describing exponential decline from a defined starting value, with
an increasing rate constant, supposedly caused by microbial growth</p>
    </div>

    <pre class="usage"><span class='fu'>logistic.solution</span><span class='op'>(</span><span class='va'>t</span>, <span class='va'>parent_0</span>, <span class='va'>kmax</span>, <span class='va'>k0</span>, <span class='va'>r</span><span class='op'>)</span></pre>

    <h2 class="hasAnchor" id="arguments"><a class="anchor" href="#arguments"></a>Arguments</h2>
    <table class="ref-arguments">
    <colgroup><col class="name" /><col class="desc" /></colgroup>
    <tr>
      <th>t</th>
      <td><p>Time.</p></td>
    </tr>
    <tr>
      <th>parent_0</th>
      <td><p>Starting value for the response variable at time zero.</p></td>
    </tr>
    <tr>
      <th>kmax</th>
      <td><p>Maximum rate constant.</p></td>
    </tr>
    <tr>
      <th>k0</th>
      <td><p>Minimum rate constant effective at time zero.</p></td>
    </tr>
    <tr>
      <th>r</th>
      <td><p>Growth rate of the increase in the rate constant.</p></td>
    </tr>
    </table>

    <h2 class="hasAnchor" id="value"><a class="anchor" href="#value"></a>Value</h2>

    <p>The value of the response variable at time <code>t</code>.</p>
    <h2 class="hasAnchor" id="note"><a class="anchor" href="#note"></a>Note</h2>

    <p>The solution of the logistic model reduces to the
<code><a href='SFO.solution.html'>SFO.solution</a></code> if <code>k0</code> is equal to <code>kmax</code>.</p>
    <h2 class="hasAnchor" id="references"><a class="anchor" href="#references"></a>References</h2>

    <p>FOCUS (2006) &#8220;Guidance Document on Estimating Persistence
and Degradation Kinetics from Environmental Fate Studies on Pesticides in
EU Registration&#8221; Report of the FOCUS Work Group on Degradation Kinetics,
EC Document Reference Sanco/10058/2005 version 2.0, 434 pp,
<a href='http://esdac.jrc.ec.europa.eu/projects/degradation-kinetics'>http://esdac.jrc.ec.europa.eu/projects/degradation-kinetics</a>
FOCUS (2014) &#8220;Generic guidance for Estimating Persistence
and Degradation Kinetics from Environmental Fate Studies on Pesticides in
EU Registration&#8221; Report of the FOCUS Work Group on Degradation Kinetics,
Version 1.1, 18 December 2014
<a href='http://esdac.jrc.ec.europa.eu/projects/degradation-kinetics'>http://esdac.jrc.ec.europa.eu/projects/degradation-kinetics</a></p>
    <h2 class="hasAnchor" id="see-also"><a class="anchor" href="#see-also"></a>See also</h2>

    <div class='dont-index'><p>Other parent solutions: 
<code><a href='DFOP.solution.html'>DFOP.solution</a>()</code>,
<code><a href='FOMC.solution.html'>FOMC.solution</a>()</code>,
<code><a href='HS.solution.html'>HS.solution</a>()</code>,
<code><a href='IORE.solution.html'>IORE.solution</a>()</code>,
<code><a href='SFO.solution.html'>SFO.solution</a>()</code>,
<code><a href='SFORB.solution.html'>SFORB.solution</a>()</code></p></div>

    <h2 class="hasAnchor" id="examples"><a class="anchor" href="#examples"></a>Examples</h2>
    <pre class="examples"><div class='input'>
  <span class='co'># Reproduce the plot on page 57 of FOCUS (2014)</span>
  <span class='fu'><a href='https://rdrr.io/r/graphics/plot.default.html'>plot</a></span><span class='op'>(</span><span class='kw'>function</span><span class='op'>(</span><span class='va'>x</span><span class='op'>)</span> <span class='fu'>logistic.solution</span><span class='op'>(</span><span class='va'>x</span>, <span class='fl'>100</span>, <span class='fl'>0.08</span>, <span class='fl'>0.0001</span>, <span class='fl'>0.2</span><span class='op'>)</span>,
       from <span class='op'>=</span> <span class='fl'>0</span>, to <span class='op'>=</span> <span class='fl'>100</span>, ylim <span class='op'>=</span> <span class='fu'><a href='https://rdrr.io/r/base/c.html'>c</a></span><span class='op'>(</span><span class='fl'>0</span>, <span class='fl'>100</span><span class='op'>)</span>,
       xlab <span class='op'>=</span> <span class='st'>"Time"</span>, ylab <span class='op'>=</span> <span class='st'>"Residue"</span><span class='op'>)</span>
</div><div class='input'>  <span class='fu'><a href='https://rdrr.io/r/graphics/plot.default.html'>plot</a></span><span class='op'>(</span><span class='kw'>function</span><span class='op'>(</span><span class='va'>x</span><span class='op'>)</span> <span class='fu'>logistic.solution</span><span class='op'>(</span><span class='va'>x</span>, <span class='fl'>100</span>, <span class='fl'>0.08</span>, <span class='fl'>0.0001</span>, <span class='fl'>0.4</span><span class='op'>)</span>,
       from <span class='op'>=</span> <span class='fl'>0</span>, to <span class='op'>=</span> <span class='fl'>100</span>, add <span class='op'>=</span> <span class='cn'>TRUE</span>, lty <span class='op'>=</span> <span class='fl'>2</span>, col <span class='op'>=</span> <span class='fl'>2</span><span class='op'>)</span>
</div><div class='input'>  <span class='fu'><a href='https://rdrr.io/r/graphics/plot.default.html'>plot</a></span><span class='op'>(</span><span class='kw'>function</span><span class='op'>(</span><span class='va'>x</span><span class='op'>)</span> <span class='fu'>logistic.solution</span><span class='op'>(</span><span class='va'>x</span>, <span class='fl'>100</span>, <span class='fl'>0.08</span>, <span class='fl'>0.0001</span>, <span class='fl'>0.8</span><span class='op'>)</span>,
       from <span class='op'>=</span> <span class='fl'>0</span>, to <span class='op'>=</span> <span class='fl'>100</span>, add <span class='op'>=</span> <span class='cn'>TRUE</span>, lty <span class='op'>=</span> <span class='fl'>3</span>, col <span class='op'>=</span> <span class='fl'>3</span><span class='op'>)</span>
</div><div class='input'>  <span class='fu'><a href='https://rdrr.io/r/graphics/plot.default.html'>plot</a></span><span class='op'>(</span><span class='kw'>function</span><span class='op'>(</span><span class='va'>x</span><span class='op'>)</span> <span class='fu'>logistic.solution</span><span class='op'>(</span><span class='va'>x</span>, <span class='fl'>100</span>, <span class='fl'>0.08</span>, <span class='fl'>0.001</span>, <span class='fl'>0.2</span><span class='op'>)</span>,
       from <span class='op'>=</span> <span class='fl'>0</span>, to <span class='op'>=</span> <span class='fl'>100</span>, add <span class='op'>=</span> <span class='cn'>TRUE</span>, lty <span class='op'>=</span> <span class='fl'>4</span>, col <span class='op'>=</span> <span class='fl'>4</span><span class='op'>)</span>
</div><div class='input'>  <span class='fu'><a href='https://rdrr.io/r/graphics/plot.default.html'>plot</a></span><span class='op'>(</span><span class='kw'>function</span><span class='op'>(</span><span class='va'>x</span><span class='op'>)</span> <span class='fu'>logistic.solution</span><span class='op'>(</span><span class='va'>x</span>, <span class='fl'>100</span>, <span class='fl'>0.08</span>, <span class='fl'>0.08</span>, <span class='fl'>0.2</span><span class='op'>)</span>,
       from <span class='op'>=</span> <span class='fl'>0</span>, to <span class='op'>=</span> <span class='fl'>100</span>, add <span class='op'>=</span> <span class='cn'>TRUE</span>, lty <span class='op'>=</span> <span class='fl'>5</span>, col <span class='op'>=</span> <span class='fl'>5</span><span class='op'>)</span>
</div><div class='input'>  <span class='fu'><a href='https://rdrr.io/r/graphics/legend.html'>legend</a></span><span class='op'>(</span><span class='st'>"topright"</span>, inset <span class='op'>=</span> <span class='fl'>0.05</span>,
         legend <span class='op'>=</span> <span class='fu'><a href='https://rdrr.io/r/base/paste.html'>paste0</a></span><span class='op'>(</span><span class='st'>"k0 = "</span>, <span class='fu'><a href='https://rdrr.io/r/base/c.html'>c</a></span><span class='op'>(</span><span class='fl'>0.0001</span>, <span class='fl'>0.0001</span>, <span class='fl'>0.0001</span>, <span class='fl'>0.001</span>, <span class='fl'>0.08</span><span class='op'>)</span>,
                         <span class='st'>", r = "</span>, <span class='fu'><a href='https://rdrr.io/r/base/c.html'>c</a></span><span class='op'>(</span><span class='fl'>0.2</span>, <span class='fl'>0.4</span>, <span class='fl'>0.8</span>, <span class='fl'>0.2</span>, <span class='fl'>0.2</span><span class='op'>)</span><span class='op'>)</span>,
         lty <span class='op'>=</span> <span class='fl'>1</span><span class='op'>:</span><span class='fl'>5</span>, col <span class='op'>=</span> <span class='fl'>1</span><span class='op'>:</span><span class='fl'>5</span><span class='op'>)</span>
</div><div class='img'><img src='logistic.solution-1.png' alt='' width='700' height='433' /></div><div class='input'>
  <span class='co'># Fit with synthetic data</span>
  <span class='va'>logistic</span> <span class='op'>&lt;-</span> <span class='fu'><a href='mkinmod.html'>mkinmod</a></span><span class='op'>(</span>parent <span class='op'>=</span> <span class='fu'><a href='mkinmod.html'>mkinsub</a></span><span class='op'>(</span><span class='st'>"logistic"</span><span class='op'>)</span><span class='op'>)</span>

  <span class='va'>sampling_times</span> <span class='op'>=</span> <span class='fu'><a href='https://rdrr.io/r/base/c.html'>c</a></span><span class='op'>(</span><span class='fl'>0</span>, <span class='fl'>1</span>, <span class='fl'>3</span>, <span class='fl'>7</span>, <span class='fl'>14</span>, <span class='fl'>28</span>, <span class='fl'>60</span>, <span class='fl'>90</span>, <span class='fl'>120</span><span class='op'>)</span>
  <span class='va'>parms_logistic</span> <span class='op'>&lt;-</span> <span class='fu'><a href='https://rdrr.io/r/base/c.html'>c</a></span><span class='op'>(</span>kmax <span class='op'>=</span> <span class='fl'>0.08</span>, k0 <span class='op'>=</span> <span class='fl'>0.0001</span>, r <span class='op'>=</span> <span class='fl'>0.2</span><span class='op'>)</span>
  <span class='va'>d_logistic</span> <span class='op'>&lt;-</span> <span class='fu'><a href='mkinpredict.html'>mkinpredict</a></span><span class='op'>(</span><span class='va'>logistic</span>,
    <span class='va'>parms_logistic</span>, <span class='fu'><a href='https://rdrr.io/r/base/c.html'>c</a></span><span class='op'>(</span>parent <span class='op'>=</span> <span class='fl'>100</span><span class='op'>)</span>,
    <span class='va'>sampling_times</span><span class='op'>)</span>
  <span class='va'>d_2_1</span> <span class='op'>&lt;-</span> <span class='fu'><a href='add_err.html'>add_err</a></span><span class='op'>(</span><span class='va'>d_logistic</span>,
    sdfunc <span class='op'>=</span> <span class='kw'>function</span><span class='op'>(</span><span class='va'>x</span><span class='op'>)</span> <span class='fu'><a href='sigma_twocomp.html'>sigma_twocomp</a></span><span class='op'>(</span><span class='va'>x</span>, <span class='fl'>0.5</span>, <span class='fl'>0.07</span><span class='op'>)</span>,
    n <span class='op'>=</span> <span class='fl'>1</span>, reps <span class='op'>=</span> <span class='fl'>2</span>, digits <span class='op'>=</span> <span class='fl'>5</span>, LOD <span class='op'>=</span> <span class='fl'>0.1</span>, seed <span class='op'>=</span> <span class='fl'>123456</span><span class='op'>)</span><span class='op'>[[</span><span class='fl'>1</span><span class='op'>]</span><span class='op'>]</span>

  <span class='va'>m</span> <span class='op'>&lt;-</span> <span class='fu'><a href='mkinfit.html'>mkinfit</a></span><span class='op'>(</span><span class='st'>"logistic"</span>, <span class='va'>d_2_1</span>, quiet <span class='op'>=</span> <span class='cn'>TRUE</span><span class='op'>)</span>
  <span class='fu'><a href='plot.mkinfit.html'>plot_sep</a></span><span class='op'>(</span><span class='va'>m</span><span class='op'>)</span>
</div><div class='img'><img src='logistic.solution-2.png' alt='' width='700' height='433' /></div><div class='input'>  <span class='fu'><a href='https://rdrr.io/r/base/summary.html'>summary</a></span><span class='op'>(</span><span class='va'>m</span><span class='op'>)</span><span class='op'>$</span><span class='va'>bpar</span>
</div><div class='output co'>#&gt;              Estimate   se_notrans   t value       Pr(&gt;t)        Lower
#&gt; parent_0 1.057896e+02 1.9023449703 55.610119 3.768361e-16 1.016451e+02
#&gt; kmax     6.398190e-02 0.0143201031  4.467978 3.841829e-04 3.929235e-02
#&gt; k0       1.612775e-04 0.0005866813  0.274898 3.940351e-01 5.846688e-08
#&gt; r        2.263946e-01 0.1718110715  1.317695 1.061044e-01 4.335843e-02
#&gt; sigma    5.332935e+00 0.9145907310  5.830952 4.036926e-05 3.340213e+00
#&gt;                Upper
#&gt; parent_0 109.9341588
#&gt; kmax       0.1041853
#&gt; k0         0.4448749
#&gt; r          1.1821120
#&gt; sigma      7.3256566</div><div class='input'>  <span class='fu'><a href='endpoints.html'>endpoints</a></span><span class='op'>(</span><span class='va'>m</span><span class='op'>)</span><span class='op'>$</span><span class='va'>distimes</span>
</div><div class='output co'>#&gt;            DT50     DT90  DT50_k0 DT50_kmax
#&gt; parent 36.86533 62.41511 4297.853  10.83349</div><div class='input'>
</div></pre>
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