search for: bioassays

Dear all, I'm trying reproduce an example of bioassays Yielding Concentration-Mortality Data particularly control - adjustment model from book Bioassay of Entomopathogenic Microbes and Nematodes chapter 7 with R. I used glm with family=binomial and link=probit, but I do not know how to implement parameter gamma (control mortality - mortality of the un...

It's not in R, but the system described in the pair of papers our group published in the Journal of Biomolecular Screening late last year: http://jbx.sagepub.com/cgi/content/refs/8/6/624 http://jbx.sagepub.com/cgi/content/refs/8/6/634 is based on S-PLUS and StatServer. It was also presented at the Insightful Tech. Conf. back in 2000. For Excel/R connection, look for the R-(D)COM server on

R Package Developer / Consulting Statistician Burlington, Vermont Precision Bioassay is a small and growing statistical consulting firm specializing in the design and analysis of biological assays of pharmaceutical proteins and vaccines. We are building a turnkey software solution for cell culture bioassay that integrates optimal design of bioassay experiments, implementation of designs using

Hello, I recently stumbled upon the fact that different 32-bit R Windows versions produce slightly different results when calling 'lm'. More precisely, this seems to be caused by a change in the transition from R 3.2.x to R 3.3.0. A minimal example, for reproducing this is "lm(y~x, data.frame(x=c(1,2,3), y=c(1,2,3)))". In R 3.3.0 the result is Call: lm(formula = y ~ x, data =

Hello, I am working on tests to compare figures. I have been using ImageMagick, which creates a figure signature, and I can compare a "test" figure signature against a saved "reference" figure signature. It seems to work pretty well. However, it is slow as it requires reading from the file system. Are there any options to compare figures on memory? For example, if I

Hello, In my code I found something that looks like an anomaly, I found a reproducible example in which I am just trying to compare each row in a data frame against the first row: a<-data.frame(row=c("B","C","B"),column=c(2,2,10),assay=c("Assay1","Assay1","Assay1"),plate=c(1,1,1),stringsAsFactors=FALSE) apply(a[1:2,],1,function(x) {

I suggest perceptual diff. You could write a wrapper around it. http://pdiff.sourceforge.net On Mon, 7 May 2018 16:49 Ramiro Barrantes, <ramiro at precisionbioassay.com> wrote: > Hello, > > I am working on tests to compare figures. I have been using ImageMagick, > which creates a figure signature, and I can compare a "test" figure > signature against a saved

In this real example (below), all four of the replicates in one treatment combination had zero failures, and this produced a very high standard error in the summary.lm. =20 Just adding one failure to one of the replicates produced a well-behaved standard error. =20 I don't know if this is a bug, but it is certainly hard for users to understand. =20 I would value your comments=20 =20 Thanks =20

Hi all, Here is my problem: I performed bioassays using a unique insecticide on 9 different genotypes and got their mortality depending on the dose of insecticide used. Now, I want to see wether some genotypes are different or not in their responses to insecticide. My problem is that I have up to four replicates for some genotypes, but only one fo...

Get articles from http://www.jstatsoft.org Firth Bradley-Terry Models in R Volume 12, Issue 01 Sturtz, Ligges, and Gelman R2WinBUGS: A Package for Running WinBUGS from R Volume 12, Issue 03 Mineo and Ruggieri A Software Tool for the Exponential Power Distribution: The normalp Package Volume 12, Issue 04 Ritz and Streibig Bioassay Analysis Using R Volume 12, Issue 05 Baddeley and Turner

Get articles from http://www.jstatsoft.org Firth Bradley-Terry Models in R Volume 12, Issue 01 Sturtz, Ligges, and Gelman R2WinBUGS: A Package for Running WinBUGS from R Volume 12, Issue 03 Mineo and Ruggieri A Software Tool for the Exponential Power Distribution: The normalp Package Volume 12, Issue 04 Ritz and Streibig Bioassay Analysis Using R Volume 12, Issue 05 Baddeley and Turner

Hello R users, I've read the posts on this topic, and had a look at the R documentation for nlme, but I can't seem to make this work. I'd like to be able to fit a mixed effects model with crossed random effects, but also be able to specify the covariance matrix structure for the residuals. Here's the syntax using the lmer function in lme4 (which doesn't currently allow

Hi, I am trying to use F test or Chi-square test to test if 2 5-parameter (A, B, xmid, scal and H) logistic curves are parallel based on residual sum of squares. What's usually done is to first fit the 2 curves using a constraint (or global) model where all parameters are kept the same except for "xmid"; then fit 2 independent curves using unconstraint models where all 5 parameters

Hi Everyone, I have data in a long format e.g. there is one row per patient but each follow-up appointment is included in the row. So, a snippet of the data looks like this: TrialNo Drug Sex Rand Adate1 Date1 Dose1 Time1 Adate2 Date2 Dose2 Time2 B1001029 LTG M 15719 30/04/2003 15825 150 106 29/08/2003 15946 200 227 B1117003 LTG M 15734 30/04/2003 15825 200 91 03/09/2003 15951 250 217

Hi All! I am desperately needing some help figuring out how to calculate LD50 with a GLMM (probit link) or, more importantly, the standard error of the LD50. I conducted a cold temperature experiment and am trying to assess after how long 50% of the insects had died (I had 3 different instars (non significant fixed effect) and several different blocks (I did 4 replicates at a time)=