aboutsummaryrefslogtreecommitdiff
path: root/docs/dev/articles/mkin.html
diff options
context:
space:
mode:
Diffstat (limited to 'docs/dev/articles/mkin.html')
-rw-r--r--docs/dev/articles/mkin.html414
1 files changed, 414 insertions, 0 deletions
diff --git a/docs/dev/articles/mkin.html b/docs/dev/articles/mkin.html
new file mode 100644
index 00000000..30b2182f
--- /dev/null
+++ b/docs/dev/articles/mkin.html
@@ -0,0 +1,414 @@
+<!DOCTYPE html>
+<!-- Generated by pkgdown: do not edit by hand --><html lang="en">
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+<meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
+<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+<title>Short introduction to mkin • mkin</title>
+<script src="../deps/jquery-3.6.0/jquery-3.6.0.min.js"></script><meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+<link href="../deps/bootstrap-5.3.1/bootstrap.min.css" rel="stylesheet">
+<script src="../deps/bootstrap-5.3.1/bootstrap.bundle.min.js"></script><link href="../deps/font-awesome-6.5.2/css/all.min.css" rel="stylesheet">
+<link href="../deps/font-awesome-6.5.2/css/v4-shims.min.css" rel="stylesheet">
+<script src="../deps/headroom-0.11.0/headroom.min.js"></script><script src="../deps/headroom-0.11.0/jQuery.headroom.min.js"></script><script src="../deps/bootstrap-toc-1.0.1/bootstrap-toc.min.js"></script><script src="../deps/clipboard.js-2.0.11/clipboard.min.js"></script><script src="../deps/search-1.0.0/autocomplete.jquery.min.js"></script><script src="../deps/search-1.0.0/fuse.min.js"></script><script src="../deps/search-1.0.0/mark.min.js"></script><!-- pkgdown --><script src="../pkgdown.js"></script><meta property="og:title" content="Short introduction to mkin">
+<meta name="robots" content="noindex">
+</head>
+<body>
+ <a href="#main" class="visually-hidden-focusable">Skip to contents</a>
+
+
+ <nav class="navbar navbar-expand-lg fixed-top bg-light" data-bs-theme="default" aria-label="Site navigation"><div class="container">
+
+ <a class="navbar-brand me-2" href="../index.html">mkin</a>
+
+ <small class="nav-text text-info me-auto" data-bs-toggle="tooltip" data-bs-placement="bottom" title="In-development version">1.2.10</small>
+
+
+ <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbar" aria-controls="navbar" aria-expanded="false" aria-label="Toggle navigation">
+ <span class="navbar-toggler-icon"></span>
+ </button>
+
+ <div id="navbar" class="collapse navbar-collapse ms-3">
+ <ul class="navbar-nav me-auto">
+<li class="nav-item"><a class="nav-link" href="../reference/index.html">Reference</a></li>
+<li class="active nav-item dropdown">
+ <button class="nav-link dropdown-toggle" type="button" id="dropdown-articles" data-bs-toggle="dropdown" aria-expanded="false" aria-haspopup="true">Articles</button>
+ <ul class="dropdown-menu" aria-labelledby="dropdown-articles">
+<li><a class="dropdown-item" href="../articles/mkin.html">Introduction to mkin</a></li>
+ <li><hr class="dropdown-divider"></li>
+ <li><h6 class="dropdown-header" data-toc-skip>Example evaluations with (generalised) nonlinear least squares</h6></li>
+ <li><a class="dropdown-item" href="../articles/FOCUS_D.html">Example evaluation of FOCUS Example Dataset D</a></li>
+ <li><a class="dropdown-item" href="../articles/FOCUS_L.html">Example evaluation of FOCUS Laboratory Data L1 to L3</a></li>
+ <li><a class="dropdown-item" href="../articles/web_only/FOCUS_Z.html">Example evaluation of FOCUS Example Dataset Z</a></li>
+ <li><hr class="dropdown-divider"></li>
+ <li><h6 class="dropdown-header" data-toc-skip>Example evaluations with hierarchical models (nonlinear mixed-effects models)</h6></li>
+ <li><a class="dropdown-item" href="../articles/prebuilt/2022_dmta_parent.html">Testing hierarchical parent degradation kinetics with residue data on dimethenamid and dimethenamid-P</a></li>
+ <li><a class="dropdown-item" href="../articles/prebuilt/2022_dmta_pathway.html">Testing hierarchical pathway kinetics with residue data on dimethenamid and dimethenamid-P</a></li>
+ <li><a class="dropdown-item" href="../articles/prebuilt/2023_mesotrione_parent.html">Testing covariate modelling in hierarchical parent degradation kinetics with residue data on mesotrione</a></li>
+ <li><a class="dropdown-item" href="../articles/prebuilt/2022_cyan_pathway.html">Testing hierarchical pathway kinetics with residue data on cyantraniliprole</a></li>
+ <li><a class="dropdown-item" href="../articles/web_only/dimethenamid_2018.html">Comparison of saemix and nlme evaluations of dimethenamid data from 2018</a></li>
+ <li><a class="dropdown-item" href="../articles/web_only/multistart.html">Short demo of the multistart method</a></li>
+ <li><hr class="dropdown-divider"></li>
+ <li><h6 class="dropdown-header" data-toc-skip>Performance</h6></li>
+ <li><a class="dropdown-item" href="../articles/web_only/compiled_models.html">Performance benefit by using compiled model definitions in mkin</a></li>
+ <li><a class="dropdown-item" href="../articles/web_only/benchmarks.html">Benchmark timings for mkin</a></li>
+ <li><a class="dropdown-item" href="../articles/web_only/saem_benchmarks.html">Benchmark timings for saem.mmkin</a></li>
+ <li><hr class="dropdown-divider"></li>
+ <li><h6 class="dropdown-header" data-toc-skip>Miscellaneous</h6></li>
+ <li><a class="dropdown-item" href="../articles/twa.html">Calculation of time weighted average concentrations with mkin</a></li>
+ <li><a class="dropdown-item" href="../articles/web_only/NAFTA_examples.html">Example evaluation of NAFTA SOP Attachment examples</a></li>
+ </ul>
+</li>
+<li class="nav-item"><a class="nav-link" href="../coverage/coverage.html">Test coverage</a></li>
+<li class="nav-item"><a class="nav-link" href="../news/index.html">News</a></li>
+ </ul>
+<ul class="navbar-nav">
+<li class="nav-item"><form class="form-inline" role="search">
+ <input class="form-control" type="search" name="search-input" id="search-input" autocomplete="off" aria-label="Search site" placeholder="Search for" data-search-index="../search.json">
+</form></li>
+<li class="nav-item"><a class="external-link nav-link" href="https://github.com/jranke/mkin/" aria-label="GitHub"><span class="fa fab fa-github fa-lg"></span></a></li>
+ </ul>
+</div>
+
+
+ </div>
+</nav><div class="container template-article">
+
+
+
+
+<div class="row">
+ <main id="main" class="col-md-9"><div class="page-header">
+
+ <h1>Short introduction to mkin</h1>
+ <h4 data-toc-skip class="author">Johannes
+Ranke</h4>
+
+ <h4 data-toc-skip class="date">Last change 18 May 2023
+(rebuilt 2025-02-14)</h4>
+
+ <small class="dont-index">Source: <a href="https://github.com/jranke/mkin/blob/HEAD/vignettes/mkin.rmd" class="external-link"><code>vignettes/mkin.rmd</code></a></small>
+ <div class="d-none name"><code>mkin.rmd</code></div>
+ </div>
+
+
+
+<p><a href="https://www.jrwb.de" class="external-link">Wissenschaftlicher Berater, Kronacher
+Str. 12, 79639 Grenzach-Wyhlen, Germany</a><br> Privatdozent at the
+University of Freiburg</p>
+<div class="section level2">
+<h2 id="abstract">Abstract<a class="anchor" aria-label="anchor" href="#abstract"></a>
+</h2>
+<p>In the regulatory evaluation of chemical substances like plant
+protection products (pesticides), biocides and other chemicals,
+degradation data play an important role. For the evaluation of pesticide
+degradation experiments, detailed guidance has been developed, based on
+nonlinear optimisation. The <code>R</code> add-on package
+<code>mkin</code> implements fitting some of the models recommended in
+this guidance from within R and calculates some statistical measures for
+data series within one or more compartments, for parent and
+metabolites.</p>
+<div class="sourceCode" id="cb1"><pre class="downlit sourceCode r">
+<code class="sourceCode R"><span><span class="kw"><a href="https://rdrr.io/r/base/library.html" class="external-link">library</a></span><span class="op">(</span><span class="st"><a href="https://pkgdown.jrwb.de/mkin/">"mkin"</a></span>, quietly <span class="op">=</span> <span class="cn">TRUE</span><span class="op">)</span></span>
+<span><span class="co"># Define the kinetic model</span></span>
+<span><span class="va">m_SFO_SFO_SFO</span> <span class="op">&lt;-</span> <span class="fu"><a href="../reference/mkinmod.html">mkinmod</a></span><span class="op">(</span>parent <span class="op">=</span> <span class="fu"><a href="../reference/mkinmod.html">mkinsub</a></span><span class="op">(</span><span class="st">"SFO"</span>, <span class="st">"M1"</span><span class="op">)</span>,</span>
+<span> M1 <span class="op">=</span> <span class="fu"><a href="../reference/mkinmod.html">mkinsub</a></span><span class="op">(</span><span class="st">"SFO"</span>, <span class="st">"M2"</span><span class="op">)</span>,</span>
+<span> M2 <span class="op">=</span> <span class="fu"><a href="../reference/mkinmod.html">mkinsub</a></span><span class="op">(</span><span class="st">"SFO"</span><span class="op">)</span>,</span>
+<span> use_of_ff <span class="op">=</span> <span class="st">"max"</span>, quiet <span class="op">=</span> <span class="cn">TRUE</span><span class="op">)</span></span>
+<span></span>
+<span></span>
+<span><span class="co"># Produce model predictions using some arbitrary parameters</span></span>
+<span><span class="va">sampling_times</span> <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">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>
+<span><span class="va">d_SFO_SFO_SFO</span> <span class="op">&lt;-</span> <span class="fu"><a href="../reference/mkinpredict.html">mkinpredict</a></span><span class="op">(</span><span class="va">m_SFO_SFO_SFO</span>,</span>
+<span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span>k_parent <span class="op">=</span> <span class="fl">0.03</span>,</span>
+<span> f_parent_to_M1 <span class="op">=</span> <span class="fl">0.5</span>, k_M1 <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/Log.html" class="external-link">log</a></span><span class="op">(</span><span class="fl">2</span><span class="op">)</span><span class="op">/</span><span class="fl">100</span>,</span>
+<span> f_M1_to_M2 <span class="op">=</span> <span class="fl">0.9</span>, k_M2 <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/Log.html" class="external-link">log</a></span><span class="op">(</span><span class="fl">2</span><span class="op">)</span><span class="op">/</span><span class="fl">50</span><span class="op">)</span>,</span>
+<span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span>parent <span class="op">=</span> <span class="fl">100</span>, M1 <span class="op">=</span> <span class="fl">0</span>, M2 <span class="op">=</span> <span class="fl">0</span><span class="op">)</span>,</span>
+<span> <span class="va">sampling_times</span><span class="op">)</span></span>
+<span></span>
+<span><span class="co"># Generate a dataset by adding normally distributed errors with</span></span>
+<span><span class="co"># standard deviation 3, for two replicates at each sampling time</span></span>
+<span><span class="va">d_SFO_SFO_SFO_err</span> <span class="op">&lt;-</span> <span class="fu"><a href="../reference/add_err.html">add_err</a></span><span class="op">(</span><span class="va">d_SFO_SFO_SFO</span>, reps <span class="op">=</span> <span class="fl">2</span>,</span>
+<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="fl">3</span>,</span>
+<span> n <span class="op">=</span> <span class="fl">1</span>, seed <span class="op">=</span> <span class="fl">123456789</span> <span class="op">)</span></span>
+<span></span>
+<span><span class="co"># Fit the model to the dataset</span></span>
+<span><span class="va">f_SFO_SFO_SFO</span> <span class="op">&lt;-</span> <span class="fu"><a href="../reference/mkinfit.html">mkinfit</a></span><span class="op">(</span><span class="va">m_SFO_SFO_SFO</span>, <span class="va">d_SFO_SFO_SFO_err</span><span class="op">[[</span><span class="fl">1</span><span class="op">]</span><span class="op">]</span>, quiet <span class="op">=</span> <span class="cn">TRUE</span><span class="op">)</span></span>
+<span></span>
+<span><span class="co"># Plot the results separately for parent and metabolites</span></span>
+<span><span class="fu"><a href="../reference/plot.mkinfit.html">plot_sep</a></span><span class="op">(</span><span class="va">f_SFO_SFO_SFO</span>, lpos <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"topright"</span>, <span class="st">"bottomright"</span>, <span class="st">"bottomright"</span><span class="op">)</span><span class="op">)</span></span></code></pre></div>
+<p><img src="mkin_files/figure-html/unnamed-chunk-2-1.png" width="768"></p>
+</div>
+<div class="section level2">
+<h2 id="background">Background<a class="anchor" aria-label="anchor" href="#background"></a>
+</h2>
+<p>The <code>mkin</code> package <span class="citation">(J. Ranke
+2021)</span> implements the approach to degradation kinetics recommended
+in the kinetics report provided by the FOrum for Co-ordination of
+pesticide fate models and their USe <span class="citation">(FOCUS Work
+Group on Degradation Kinetics 2006, 2014)</span>. It covers data series
+describing the decline of one compound, data series with transformation
+products (commonly termed metabolites) and data series for more than one
+compartment. It is possible to include back reactions. Therefore,
+equilibrium reactions and equilibrium partitioning can be specified,
+although this often leads to an overparameterisation of the model.</p>
+<p>When the first <code>mkin</code> code was published in 2010, the most
+commonly used tools for fitting more complex kinetic degradation models
+to experimental data were KinGUI <span class="citation">(Schäfer et al.
+2007)</span>, a MATLAB based tool with a graphical user interface that
+was specifically tailored to the task and included some output as
+proposed by the FOCUS Kinetics Workgroup, and ModelMaker, a general
+purpose compartment based tool providing infrastructure for fitting
+dynamic simulation models based on differential equations to data.</p>
+<p>The ‘mkin’ code was first uploaded to the BerliOS development
+platform. When this was taken down, the version control history was
+imported into the R-Forge site (see <em>e.g.</em> <a href="https://cgit.jrwb.de/mkin/commit/?id=30cbb4092f6d2d3beff5800603374a0d009ad770" class="external-link">the
+initial commit on 11 May 2010</a>), where the code is still being
+updated.</p>
+<p>At that time, the R package <code>FME</code> (Flexible Modelling
+Environment) <span class="citation">(Soetaert and Petzoldt 2010)</span>
+was already available, and provided a good basis for developing a
+package specifically tailored to the task. The remaining challenge was
+to make it as easy as possible for the users (including the author of
+this vignette) to specify the system of differential equations and to
+include the output requested by the FOCUS guidance, such as the
+<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><msup><mi>χ</mi><mn>2</mn></msup><annotation encoding="application/x-tex">\chi^2</annotation></semantics></math>
+error level as defined in this guidance.</p>
+<p>Also, <code>mkin</code> introduced using analytical solutions for
+parent only kinetics for improved optimization speed. Later, Eigenvalue
+based solutions were introduced to <code>mkin</code> for the case of
+linear differential equations (<em>i.e.</em> where the FOMC or DFOP
+models were not used for the parent compound), greatly improving the
+optimization speed for these cases. This, has become somehow obsolete,
+as the use of compiled code described below gives even faster execution
+times.</p>
+<p>The possibility to specify back-reactions and a biphasic model
+(SFORB) for metabolites were present in <code>mkin</code> from the very
+beginning.</p>
+<div class="section level3">
+<h3 id="derived-software-tools">Derived software tools<a class="anchor" aria-label="anchor" href="#derived-software-tools"></a>
+</h3>
+<p>Soon after the publication of <code>mkin</code>, two derived tools
+were published, namely KinGUII (developed at Bayer Crop Science) and
+CAKE (commissioned to Tessella by Syngenta), which added a graphical
+user interface (GUI), and added fitting by iteratively reweighted least
+squares (IRLS) and characterisation of likely parameter distributions by
+Markov Chain Monte Carlo (MCMC) sampling.</p>
+<p>CAKE focuses on a smooth use experience, sacrificing some flexibility
+in the model definition, originally allowing only two primary
+metabolites in parallel. The current version 3.4 of CAKE released in May
+2020 uses a scheme for up to six metabolites in a flexible arrangement
+and supports biphasic modelling of metabolites, but does not support
+back-reactions (non-instantaneous equilibria).</p>
+<p>KinGUI offers an even more flexible widget for specifying complex
+kinetic models. Back-reactions (non-instantaneous equilibria) were
+supported early on, but until 2014, only simple first-order models could
+be specified for transformation products. Starting with KinGUII version
+2.1, biphasic modelling of metabolites was also available in
+KinGUII.</p>
+<p>A further graphical user interface (GUI) that has recently been
+brought to a decent degree of maturity is the browser based GUI named
+<code>gmkin</code>. Please see its <a href="https://pkgdown.jrwb.de/gmkin/" class="external-link">documentation page</a> and <a href="https://pkgdown.jrwb.de/gmkin/articles/gmkin_manual.html" class="external-link">manual</a>
+for further information.</p>
+<p>A comparison of scope, usability and numerical results obtained with
+these tools has been recently been published by <span class="citation">Johannes Ranke, Wöltjen, and Meinecke
+(2018)</span>.</p>
+</div>
+</div>
+<div class="section level2">
+<h2 id="unique-features">Unique features<a class="anchor" aria-label="anchor" href="#unique-features"></a>
+</h2>
+<p>Currently, the main unique features available in <code>mkin</code>
+are</p>
+<ul>
+<li>the <a href="https://pkgdown.jrwb.de/mkin/articles/web_only/compiled_models.html">speed
+increase</a> by using compiled code when a compiler is present,</li>
+<li>parallel model fitting on multicore machines using the <a href="https://pkgdown.jrwb.de/mkin/reference/mmkin.html"><code>mmkin</code>
+function</a>,</li>
+<li>the estimation of parameter confidence intervals based on
+transformed parameters (see below) and</li>
+<li>the possibility to use the <a href="https://pkgdown.jrwb.de/mkin/reference/sigma_twocomp.html">two-component
+error model</a>
+</li>
+</ul>
+<p>The iteratively reweighted least squares fitting of different
+variances for each variable as introduced by <span class="citation">Gao
+et al. (2011)</span> has been available in mkin since <a href="https://pkgdown.jrwb.de/mkin/news/index.html#mkin-0-9-22-2013-10-26">version
+0.9-22</a>. With <a href="https://pkgdown.jrwb.de/mkin/news/index.html#mkin-0-9-49-5-2019-07-04">release
+0.9.49.5</a>, the IRLS algorithm has been complemented by direct or
+step-wise maximisation of the likelihood function, which makes it
+possible not only to fit the variance by variable error model but also a
+<a href="https://pkgdown.jrwb.de/mkin/reference/sigma_twocomp.html">two-component
+error model</a> inspired by error models developed in analytical
+chemistry <span class="citation">(Johannes Ranke and Meinecke
+2019)</span>.</p>
+</div>
+<div class="section level2">
+<h2 id="internal-parameter-transformations">Internal parameter transformations<a class="anchor" aria-label="anchor" href="#internal-parameter-transformations"></a>
+</h2>
+<p>For rate constants, the log transformation is used, as proposed by
+Bates and Watts <span class="citation">(1988, 77, 149)</span>.
+Approximate intervals are constructed for the transformed rate constants
+<span class="citation">(compare Bates and Watts 1988, 135)</span>,
+<em>i.e.</em> for their logarithms. Confidence intervals for the rate
+constants are then obtained using the appropriate backtransformation
+using the exponential function.</p>
+<p>In the first version of <code>mkin</code> allowing for specifying
+models using formation fractions, a home-made reparameterisation was
+used in order to ensure that the sum of formation fractions would not
+exceed unity.</p>
+<p>This method is still used in the current version of KinGUII (v2.1
+from April 2014), with a modification that allows for fixing the pathway
+to sink to zero. CAKE uses penalties in the objective function in order
+to enforce this constraint.</p>
+<p>In 2012, an alternative reparameterisation of the formation fractions
+was proposed together with René Lehmann <span class="citation">(J. Ranke
+and Lehmann 2012)</span>, based on isometric logratio transformation
+(ILR). The aim was to improve the validity of the linear approximation
+of the objective function during the parameter estimation procedure as
+well as in the subsequent calculation of parameter confidence intervals.
+In the current version of mkin, a logit transformation is used for
+parameters that are bound between 0 and 1, such as the g parameter of
+the DFOP model.</p>
+<div class="section level3">
+<h3 id="confidence-intervals-based-on-transformed-parameters">Confidence intervals based on transformed parameters<a class="anchor" aria-label="anchor" href="#confidence-intervals-based-on-transformed-parameters"></a>
+</h3>
+<p>In the first attempt at providing improved parameter confidence
+intervals introduced to <code>mkin</code> in 2013, confidence intervals
+obtained from FME on the transformed parameters were simply all
+backtransformed one by one to yield asymmetric confidence intervals for
+the backtransformed parameters.</p>
+<p>However, while there is a 1:1 relation between the rate constants in
+the model and the transformed parameters fitted in the model, the
+parameters obtained by the isometric logratio transformation are
+calculated from the set of formation fractions that quantify the paths
+to each of the compounds formed from a specific parent compound, and no
+such 1:1 relation exists.</p>
+<p>Therefore, parameter confidence intervals for formation fractions
+obtained with this method only appear valid for the case of a single
+transformation product, where currently the logit transformation is used
+for the formation fraction.</p>
+<p>The confidence intervals obtained by backtransformation for the cases
+where a 1:1 relation between transformed and original parameter exist
+are considered by the author of this vignette to be more accurate than
+those obtained using a re-estimation of the Hessian matrix after
+backtransformation, as implemented in the FME package.</p>
+</div>
+<div class="section level3">
+<h3 id="parameter-t-test-based-on-untransformed-parameters">Parameter t-test based on untransformed parameters<a class="anchor" aria-label="anchor" href="#parameter-t-test-based-on-untransformed-parameters"></a>
+</h3>
+<p>The standard output of many nonlinear regression software packages
+includes the results from a test for significant difference from zero
+for all parameters. Such a test is also recommended to check the
+validity of rate constants in the FOCUS guidance <span class="citation">(FOCUS Work Group on Degradation Kinetics 2014,
+96ff)</span>.</p>
+<p>It has been argued that the precondition for this test, <em>i.e.</em>
+normal distribution of the estimator for the parameters, is not
+fulfilled in the case of nonlinear regression <span class="citation">(J.
+Ranke and Lehmann 2015)</span>. However, this test is commonly used by
+industry, consultants and national authorities in order to decide on the
+reliability of parameter estimates, based on the FOCUS guidance
+mentioned above. Therefore, the results of this one-sided t-test are
+included in the summary output from <code>mkin</code>.</p>
+<p>As it is not reasonable to test for significant difference of the
+transformed parameters (<em>e.g.</em>
+<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>l</mi><mi>o</mi><mi>g</mi><mrow><mo stretchy="true" form="prefix">(</mo><mi>k</mi><mo stretchy="true" form="postfix">)</mo></mrow></mrow><annotation encoding="application/x-tex">log(k)</annotation></semantics></math>)
+from zero, the t-test is calculated based on the model definition before
+parameter transformation, <em>i.e.</em> in a similar way as in packages
+that do not apply such an internal parameter transformation. A note is
+included in the <code>mkin</code> output, pointing to the fact that the
+t-test is based on the unjustified assumption of normal distribution of
+the parameter estimators.</p>
+</div>
+</div>
+<div class="section level2">
+<h2 id="references">References<a class="anchor" aria-label="anchor" href="#references"></a>
+</h2>
+<!-- vim: set foldmethod=syntax: -->
+<div id="refs" class="references csl-bib-body hanging-indent">
+<div id="ref-bates1988" class="csl-entry">
+Bates, D., and D. Watts. 1988. <em>Nonlinear Regression and Its
+Applications</em>. Wiley-Interscience.
+</div>
+<div id="ref-FOCUS2006" class="csl-entry">
+FOCUS Work Group on Degradation Kinetics. 2006. <em>Guidance Document on
+Estimating Persistence and Degradation Kinetics from Environmental Fate
+Studies on Pesticides in EU Registration. Report of the FOCUS Work Group
+on Degradation Kinetics</em>. <a href="http://esdac.jrc.ec.europa.eu/projects/degradation-kinetics" class="external-link">http://esdac.jrc.ec.europa.eu/projects/degradation-kinetics</a>.
+</div>
+<div id="ref-FOCUSkinetics2014" class="csl-entry">
+———. 2014. <em>Generic Guidance for Estimating Persistence and
+Degradation Kinetics from Environmental Fate Studies on Pesticides in EU
+Registration</em>. 1.1 ed. <a href="http://esdac.jrc.ec.europa.eu/projects/degradation-kinetics" class="external-link">http://esdac.jrc.ec.europa.eu/projects/degradation-kinetics</a>.
+</div>
+<div id="ref-gao11" class="csl-entry">
+Gao, Z., J. W. Green, J. Vanderborght, and W. Schmitt. 2011.
+<span>“Improving Uncertainty Analysis in Kinetic Evaluations Using
+Iteratively Reweighted Least Squares.”</span> Journal. <em>Environmental
+Science and Technology</em> 45: 4429–37.
+</div>
+<div id="ref-pkg:mkin" class="csl-entry">
+Ranke, J. 2021. <em>‘<span class="nocase">mkin</span>‘:
+<span>K</span>inetic Evaluation of Chemical Degradation Data</em>. <a href="https://CRAN.R-project.org/package=mkin" class="external-link">https://CRAN.R-project.org/package=mkin</a>.
+</div>
+<div id="ref-ranke2012" class="csl-entry">
+Ranke, J., and R. Lehmann. 2012. <span>“Parameter Reliability in Kinetic
+Evaluation of Environmental Metabolism Data - Assessment and the
+Influence of Model Specification.”</span> In <em>SETAC World 20-24
+May</em>. Berlin. <a href="https://jrwb.de/posters/Poster_SETAC_2012_Kinetic_parameter_uncertainty_model_parameterization_Lehmann_Ranke.pdf" class="external-link">https://jrwb.de/posters/Poster_SETAC_2012_Kinetic_parameter_uncertainty_model_parameterization_Lehmann_Ranke.pdf</a>.
+</div>
+<div id="ref-ranke2015" class="csl-entry">
+———. 2015. <span>“To t-Test or Not to t-Test, That Is the
+Question.”</span> In <em>XV Symposium on Pesticide Chemistry 2-4
+September 2015</em>. Piacenza. <a href="https://jrwb.de/posters/piacenza_2015.pdf" class="external-link">https://jrwb.de/posters/piacenza_2015.pdf</a>.
+</div>
+<div id="ref-ranke2019" class="csl-entry">
+Ranke, Johannes, and Stefan Meinecke. 2019. <span>“Error Models for the
+Kinetic Evaluation of Chemical Degradation Data.”</span>
+<em>Environments</em> 6 (12). <a href="https://doi.org/10.3390/environments6120124" class="external-link">https://doi.org/10.3390/environments6120124</a>.
+</div>
+<div id="ref-ranke2018" class="csl-entry">
+Ranke, Johannes, Janina Wöltjen, and Stefan Meinecke. 2018.
+<span>“Comparison of Software Tools for Kinetic Evaluation of Chemical
+Degradation Data.”</span> <em>Environmental Sciences Europe</em> 30 (1):
+17. <a href="https://doi.org/10.1186/s12302-018-0145-1" class="external-link">https://doi.org/10.1186/s12302-018-0145-1</a>.
+</div>
+<div id="ref-schaefer2007" class="csl-entry">
+Schäfer, D., B. Mikolasch, P. Rainbird, and B. Harvey. 2007.
+<span>“<span>KinGUI</span>: A New Kinetic Software Tool for Evaluations
+According to <span>FOCUS</span> Degradation Kinetics.”</span> In
+<em>Proceedings of the XIII Symposium Pesticide Chemistry</em>, edited
+by Del Re A. A. M., Capri E., Fragoulis G., and Trevisan M., 916–23.
+Piacenza.
+</div>
+<div id="ref-soetaert2010" class="csl-entry">
+Soetaert, Karline, and Thomas Petzoldt. 2010. <span>“Inverse Modelling,
+Sensitivity and Monte Carlo Analysis in <span>R</span> Using Package
+<span>FME</span>.”</span> <em>Journal of Statistical Software</em> 33
+(3): 1–28. <a href="https://doi.org/10.18637/jss.v033.i03" class="external-link">https://doi.org/10.18637/jss.v033.i03</a>.
+</div>
+</div>
+</div>
+ </main><aside class="col-md-3"><nav id="toc" aria-label="Table of contents"><h2>On this page</h2>
+ </nav></aside>
+</div>
+
+
+
+ <footer><div class="pkgdown-footer-left">
+ <p>Developed by Johannes Ranke.</p>
+</div>
+
+<div class="pkgdown-footer-right">
+ <p>Site built with <a href="https://pkgdown.r-lib.org/" class="external-link">pkgdown</a> 2.1.1.</p>
+</div>
+
+ </footer>
+</div>
+
+
+
+
+
+ </body>
+</html>

Contact - Imprint