similar to: subset point data set by distance ranges

Dear R-users, I am currently modifying a previously developed predator prey model and was curious if there was a way to add in a disturbance to the model (let's say at time t=100). The disturbance can be the introduction of 40 prey (N=40) and 10 predators (Pred = 10). I would like to see my model go from a state of equilibrium (up to t = 99), show this disturbance (at t = 100) and then

Hi, I have data on stomach contents. Possible prey species are in the hundreds, so a list of prey codes has been in used in many labs doing this kind of work. When comes time to do analyses on these data one often wants to regroup prey in broader categories, especially for rare prey. In SAS you can nest a large number of "if-else", or do this more cleanly with "select"

Greetings This is a long email. I'm struggling with a data set comprising 2,278 hydroacoustic estimates of fish biomass density made along line transects in two lakes (lakes Michigan and Huron, three years in each lake). The data represent lakewide surveys in each year and each data point represents the estimate for a horizontal interval 1 km in length. I'm interested in comparing

Hi all, I''ve a problem when submitting a form : the URL seems to be invalid. I really don''t see the way I should try to solve that problem. I searched on the web, but didn''t found any kind of that problem. Here is the code : require ''mechanize'' agent = WWW::Mechanize.new page =

Hi, I'm trying to move to R the last few data handling routines I was performing in SAS. I'm working on stomach content data. In the simplified example I provide below, there are variables describing the origin of each prey item (nbpc is a ship number, each ship may have been used on different trips, each trip has stations, and individual fish (tagno) can be caught at each

Hi R experts :) I'm trying to carry out a survival model on my data, but I am unsure of whether it's appropriate or if I should do something specific in regards to hazard. My data is time to death by predator where I have 8 prey and one predator in the setting. This means that two prey can't possibly die at the same time and I can't quite get my head around how to include this in

Hi, I wonder if anyone can help me with specifying a right model for my analysis. I am a beginner to lme methods and though have spent already many hours studying from various books an on-line helps, I was unfortunately not able to find a solution to my problem on my own. Data structure: I studied escape behavior of three species of a prey to a predator. The prey specimens (many) were in a

I was playing around a bit to see how I could find the two points in a set of points (or ordered pairs) furthest from each other. Here's what I did: 1) created a Nrow by 2col matrix, so each row contains an x,y coordinate pair. 2) fed the matrix to a nested mapply (cv is my matrix): mapply(function(k,l) mapply(function(x,y,a,b) +

Dear R friends- I'm attempting to generate a regression tree with one gradient predictor and multiple responses, trying to test if change in size (turtle.data$Clength) acts as a single predictor of ten multiple diet taxa abundances (prey.data) Neither rpart or mvpart seem to allow me to do multiple responses. (Or if they can, I'm not using the functions properly.) > library(rpart)

I have installed Prey onto my pc running PCLinuxOS following the instructions in http://frankscorner.org/index.php?p=prey or http://appdb.winehq.org/objectManager.php?sClass=application&iId=3465 and tried running it. I then found I needed the nocd patch, which I downloaded and applied. I then tried cd to the app folder, then wine prey.exe with the following result: Prey 1.0.103 win-x86 Jun 10

Hi I am struggling with the correct code syntax to generate xyplots that are different from the default graphics option. This is simplified version of my data: site size dnaconc prey A 44 22.6 1 A 47 18.2 1 B 38 25.6 0 B 47 20.5 1 C 45 30.5 0 C 32 18.5 0 D 45 15.0 1 D 22 20.1 0 So I am using xyplot(dnaconc~size|site,data=bug,groups=prey) to generate 4 panels (one for each site). My

Dear list, I´m using the mgcv package to model the proportion by weight of certain prey on the stomach content of a predator. This proportion is the ratio of two weights (prey weight over stomach weight), and ranges between 0 and 1. The variance is low when proportion is close to 0 and 1, and higher at intermediate values. It seems that the best way to go is to model this using the

Greetings all The help file for GAMM in mgcv indicates that the log likelihood for a GAMM reported using summary(my.gamm$lme) (as an example) is not correct. However, in a past R-help post (included below), there is some indication that the likelihood ratio test in anova.lme(mygamm$lme, mygamm1$lme) is valid. How can I tell if anova.lme results are meaningful (are AIC, BIC, and logLik

Hello, I am trying to model a type II functional response of number of prey eaten (Ne) against number supplied (No) with a non-linear least squares regression (nls). I am using a modification of Holling's (1959) disc equation to account for non-replacement of prey; Ne=No{1-exp[a(bNe-T)]} where a is the attack rate, b is the handling time, and T is the experimental period. My script is as

*Thanks* all those who took the time to help me (even if the "question" was not related to - the use of - R). Now I think I can soundly make my point w/ the referee (can I use your replies? If so I intend to properly cite its use?!?). Regards, Eduardo Esteves ps - Sorry for not explaining the "biological details" of my posting: RNA/DNA is the ratio of RNA content to

Hello there I have the following model based on the hollings disc equation for the type II functional response for 2 data sets: nls(eaten~(a*suppl)/(1+a*h*suppl) where eaten is the number of prey eaten by a predator and suppl is the number of prey initially supplied to the same predator. I have parameter estimates of 'a' and 'h' for the two populations studied and would like

Am Montag, den 24.03.2008, 12:06 -0700 schrieb Tanya M. Lattner: > > This is close to a showstopper for integrating an llvm-gcc bootstrap > > into the nightly tester. The llvm-gcc ./configure needs to be called > > very differently from the llvm ./configure, and keeping two sets of > > options is Not Worth The Trouble, at least IMHO. > > So you didn't like the

Dear All, I'me having (much) trouble understanding why it happened and answering a referee's comment to part of a submitted manuscript. I've tried to google for help but... I'm really confident that although this is a R-Help list someone can help me! I used R to do an ANCOVA w/ RNA/DNA as the dep var, sl as the indep var and gut (a factor w/ levels: prey and empty) as the

I did this short experiment: ggreif at my [!297] cd /home/ggreif/llvm ggreif at my [!298] find . -name "*.cpp" | xargs grep bytecode | wc -l 143 I guess these are a quick prey for perl's in-place replace. But wait! There are more: ggreif at my [!299] find . -name "*.cpp" | xargs grep -i bytecode | wc -l 291 probably all of the rest is "Bytecode"

I've got a problem regarding Win2K security on a Samba 2.2.3a domain. We've got an issue where anyone in the same domain can browse another users' C$. That's bad...bad bad bad. Any PC with the default share (C$) is easy prey. Is there a way to prevent this other than removing the share manually from each and every PC? Any thoughts would be appreciated. Al Moote