search for: nitrates

I am trying to calculate monthly means by year of phosphates and nitrates from a multi year data set. Can anybody help me out with the most effective way to do this? My data looks like this: Collection_Date                   Test.Name              Value 2000-01-24 17:00:00            Phosphate               0.108 2000-01-24 17:00:00            Nitrate                  ...

I measured nitrate concentration and primary production (PP) biweekly for 23 months in one headwater stream. I would like to use linear regression to determine if PP is related to nitrate concentration. My dataframe is called "data" and consists of the vectors Rdate, PP, and nitrate. Rdate is the observation date in class "date" and PP is primary production. I first

Hello, my name is Toby, and i live in Sydney Australia. i would like to buy a 25Kg bag of strontium nitrate and have it delivered to an address in sydney. i understand that long distance postage can sometimes be very costly, so can you please give a a quote for the 25Kg bag, plus the postage cost to my address in sydney. thankyou for your time

Hello, I'm trying to make a lattice plot (using xyplot()). I have included a "layout=c(3,4)" statement, giving me 12 plots per page and an "as.table=TRUE" statement, directing the way the plots are laid out. I have 18 plots altogether and so 6 of them end up on the second page. Everything looks fine for the first page, but the x-axis labels (e.g. 1993, 1994...) are all

Dear list users, I have trouble with covariance analysis. I measured nitrate concentrations in the soil (NO3) and the percentage of legumes (LEG, continuous), affected by 2 different CO2 concentrations (CO2, discrete). I suspect that CO2 has an effect on LEG and NO3, but also that LEG has an effect on NO3, so this is the formula I wrote to test this: NO3 ~ CO2 + LEG + CO2:LEG Will LEG be

Hi, how are you? My name is Irucka Embry and I would like assistance on properly subsetting some data obtained from a .csv file. > file <-"info_n.csv" > INFO<- getMetaDataFromFile(file) INFO is 92 observations of 14 variables > INFO<- subset(INFO,site.no==02169570) INFO is 0 observations of 14 variables When the site.no is used I should have 1 observation of 14

Hello, I would like to perform an NMDS on the following: I have two independent variables, which are sites and treatments. I have 6 sites which are peatlands. I collected 5 replicates (at the same time) from each of the sites. I used each of the replicates in a treatment. There were 4 treatments. 2 were controls and the other two were a simulated 30 day drought and a simulated 60 day drought.

I have a question concerning the Wilcoxon signed-rank test, and specifically, which R subroutine I should use for my particular dataset. There are three different commands in R (that I'm aware of) that calculate the Wilcoxon signed-rank test; wilcox.test, wilcox.exact, and wilcoxsign_test. When I run the three commands on the same dataset, I get different p-values. I'm hoping that

#is there a way to get NA in the table of descriptive statistics instead of the function stopping Thank you in advance #data x.f <- structure(list(Site = structure(c(9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L), .Label = c("BC", "HC", "RM119", "RM148", "RM179", "RM185",

Dear list, I've been learning how to make a 2x2 paneled dotplot in lattice without any previous experience using lattice. my code thusfar is: nut<-read.table("/Users/colinwahl/Desktop/nutsimp_noerror.csv", T, sep= ",") attach(nut) nut1<-data.frame(Nitrate, Total_Nitrogen, Phosphate, Total_Phosphorus) nut1<-as.matrix(nut1) rownames(nut1)<-group

Hello, Firstly, real new to R here. I have a function intended to evaluate the values in columns spread over many tables. I have an argument in the function that allows the user to input what sequence of tables they want to draw data from. The function seems to work fine, but when the user inputs a single number (over 9) instead of a sequence using the : operator, I find an error message: the

Hi, I am trying to run a 1D nutrient-phytoplankton-zooplankton model in R using the package 'deSolve'. The code is shown below: DEPTH = seq(2.5, 147.5, 5) NPZ = function(t, state, params){ with(as.list(params), { P <- state[1:NB] Z <- state[(NB + 1): (2*NB)] N <- state[(2*NB + 1): (3*NB)] F.I = function(z, hr){ I0 = function(hr){

Dear Rich, It depends how the data is generated. Although I am not an expert in ecology, I can explain it based on a biomedical example. Certain variables are generated geometrically (exponentially), e.g. MIC or Titer. MIC = Minimum Inhibitory Concentration for bacterial resistance Titer = dilution which still has an effect, e.g. serially diluting blood samples; Obviously, diluting the

Hi, I'm trying to compile ocfs2 1.2.6 on a 2.6.21 kernel (with rsbac and pax patches), but I can't get this to work .. In 2.6.20 there was an change in the definition of the INIT_WORK macro (http://lkml.org/lkml/2006/12/5/269) this seems to cause my problems (see below) but even after removing the third parameter of the INIT_WORK calls the compile fails (see second compile failure). Can