Displaying 20 results from an estimated 88 matches for "preyed".
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2005 Jan 19
2
recoding large number of categories (select in SAS)
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"
2006 Sep 13
1
reshaping a dataset
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
2011 Mar 10
2
Not sure how to handle hazard in my survival model
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
2008 May 26
4
Prey and OpenGL
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
2007 Feb 25
1
nested design in lme, need help with specifying model
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
2010 Dec 11
2
Predator Prey Models
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
2008 Jan 30
1
How to run interaction between to categoric variables in lme()?
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2016 Apr 26
0
vectors of equations in ode / desolve
Hello,
I have a syntactic problem with ode. How do I specify vectors of
equations in ordinary differential equation systems. (i.e. in my case I
want to simulate an a priory undefined number of species that have
different parameters but the same behaviour)
I demonstrate this using the Lotka Volterra example. The code below does
not work and I have not a good idea how to specify this right.
##
2007 Dec 10
1
Multiple Reponse CART Analysis
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)
2008 Jul 13
0
Re: Prey and OpenGL
Hello again.
Since my last post about giving up on Prey I have had to change my graphics card. The cooling fan on my ATI packed up and it was a choice of a new fan/heatsink combination and having to nearly rebuild my pc to allow room for it (nearly the size of my card and over 1 inch thick !) or replacing the card.
Since I thought that the fan problem might be the thin end of the wedge and I might
2009 Jun 12
1
coupled ODE population model
I'm fairly new to R, and I'm trying to write out a population model that
satisfies the following;
the system consists of s species, i= 1, 2,...,s
network of interactions between species is specified by a (s x s) real matrix,
C[i,j]
x[i] being the relative population of the "ith" species (0 =< x[i] =< 1,
sum(x[i]=1)
the evolution rule being considered is as follows;
2006 May 01
1
xyplot: trouble changing graphics settings
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
2010 Feb 15
1
GAM for non-integer proportions
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
2008 Feb 01
2
Is it possible with two random effects in lme()?
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2010 Apr 28
1
NLS "Singular Gradient" Error
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
2008 May 29
1
In fact this is a Stats question, but... "The return."
*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
2008 Dec 10
1
subset point data set by distance ranges
Greetings
I'm using R 2.8 with recent (last month) versions of the packages I need to
use at present.
I'm interested in examining hierarchical spatio-temporal patterns in a data
set. The data consist of 94 points (X, Y, UTM coordinates) at which catch
rates for a fish were recorded and there are also estimates of prey
available for these fish at the same locations.
2011 Feb 03
1
boostrap an nls regression
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
2008 Mar 24
2
[LLVMdev] Potential breakage in llvm-gcc's ./configure
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
2008 Jun 27
3
Glusterfs could not open spec file
Dear Team,
I have installed and configured gluster in one server and client.
one time it was worked fine, again later it is not working.
my configuration files.
server
[root at rhel2 ~]# cat /etc/glusterfs/glusterfs-server.vol
volume rhel2
type storage/posix # POSIX FS translator
option directory /opt # Export this directory
end-volume
volume rhel2
type