EVOLUTION-MANAGER
Edit File: zCO2.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>R: Carbon Dioxide Uptake in Grass Plants</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link rel="stylesheet" type="text/css" href="R.css" /> </head><body> <table width="100%" summary="page for CO2 {datasets}"><tr><td>CO2 {datasets}</td><td style="text-align: right;">R Documentation</td></tr></table> <h2>Carbon Dioxide Uptake in Grass Plants</h2> <h3>Description</h3> <p>The <code>CO2</code> data frame has 84 rows and 5 columns of data from an experiment on the cold tolerance of the grass species <em>Echinochloa crus-galli</em>. </p> <h3>Usage</h3> <pre>CO2</pre> <h3>Format</h3> <p>An object of class <code>c("nfnGroupedData", "nfGroupedData", "groupedData", "data.frame")</code> containing the following columns: </p> <dl> <dt>Plant</dt><dd> <p>an ordered factor with levels <code>Qn1</code> < <code>Qn2</code> < <code>Qn3</code> < ... < <code>Mc1</code> giving a unique identifier for each plant. </p> </dd> <dt>Type</dt><dd> <p>a factor with levels <code>Quebec</code> <code>Mississippi</code> giving the origin of the plant </p> </dd> <dt>Treatment</dt><dd> <p>a factor with levels <code>nonchilled</code> <code>chilled</code> </p> </dd> <dt>conc</dt><dd> <p>a numeric vector of ambient carbon dioxide concentrations (mL/L). </p> </dd> <dt>uptake</dt><dd> <p>a numeric vector of carbon dioxide uptake rates (<i>umol/m^2</i> sec). </p> </dd> </dl> <h3>Details</h3> <p>The <i>CO2</i> uptake of six plants from Quebec and six plants from Mississippi was measured at several levels of ambient <i>CO2</i> concentration. Half the plants of each type were chilled overnight before the experiment was conducted. </p> <p>This dataset was originally part of package <code>nlme</code>, and that has methods (including for <code>[</code>, <code>as.data.frame</code>, <code>plot</code> and <code>print</code>) for its grouped-data classes. </p> <h3>Source</h3> <p>Potvin, C., Lechowicz, M. J. and Tardif, S. (1990) “The statistical analysis of ecophysiological response curves obtained from experiments involving repeated measures”, <em>Ecology</em>, <b>71</b>, 1389–1400. </p> <p>Pinheiro, J. C. and Bates, D. M. (2000) <em>Mixed-effects Models in S and S-PLUS</em>, Springer. </p> <h3>Examples</h3> <pre> require(stats); require(graphics) coplot(uptake ~ conc | Plant, data = CO2, show.given = FALSE, type = "b") ## fit the data for the first plant fm1 <- nls(uptake ~ SSasymp(conc, Asym, lrc, c0), data = CO2, subset = Plant == "Qn1") summary(fm1) ## fit each plant separately fmlist <- list() for (pp in levels(CO2$Plant)) { fmlist[[pp]] <- nls(uptake ~ SSasymp(conc, Asym, lrc, c0), data = CO2, subset = Plant == pp) } ## check the coefficients by plant print(sapply(fmlist, coef), digits = 3) </pre> <hr /><div style="text-align: center;">[Package <em>datasets</em> version 3.6.0 <a href="00Index.html">Index</a>]</div> </body></html>