search for: concentration

Displaying 20 results from an estimated 1267 matches for "concentration".

2010 Oct 15
2
Time vs Concentration Graphs by ID
Hello-- I have a data for small population who took 1 drug at 3 different doses. I have the actual drug concentrations as well as predicted concentrations by my model. This is what I'm looking for: - Time vs Concentration by ID (individual plots), with each subject occupying 1 plot -- there is to be 9 plots per page (3x3) - Observed drug concentration is made up of points, and predicted drug concentration is...
2007 Dec 28
3
How to catch data from the different dataframes and lm problem?
...to 4 dataframes. The example is as follows. Moreover, I want to calculate ?test? value for these 4 dataframes. My question is that the ?test? values not correct and I do not know where the problem is. 2) There are 12 ?test? (y) values from 1). Then, I want to model the relationship between ?concentration? (X) and ?test? (Y) by fitting the linear regression, such lm(Y~X) and this is my target. I think that if I can catch ?test? (Y) values and ?concentration? (X) values into a dataframe, then I can carry out regression. So, how to catch all ?test? values from different dataframes? Or does anyone h...
2011 Feb 05
3
spline interpolation
Hello R-help I have the following data for a standard curve concentration(nM),fluorescence 0,48.34 2,58.69 5,70.83 10,94.73 20,190.8 50,436.0 100, 957.9   (1)Is there function in R to plot a spline. (2)How can I interpolation,say 1000 point from 0nM-100nM and store this as a data frame of concentration,fluorescence (3)How can I modify the code below so that instead of r...
2009 Sep 03
2
dividing a dataframe column by different constants
Dear R users, today I've got the following problem. Here you are a dataframe as example. There are some SAMPLES for which a CONCentration was recorded through TIME. The time during which the concentration was recorded is not always the same, 10 points for Sample A, 7 points for Sample B and 11 for sample C Also the initial concentration was not the same for the three samples. I would like express the concentrations as % of the conc...
2005 Jan 13
5
PRI concentrator
Hey gang, We currently have a class 3 switch (CSX) that..well..it sucks. It does terrible CDR writes, doesn't support LCR, the list goes on and on. We want to replace this with several asterisk boxes each running one or two 4 port PRI cards. The problem is: I can plug in 20 PRI lines into the CSX (from PSTN) and have 1 come from CSX into asterisk. If 1 call comes in on each of the 20 pris,
2011 Jan 05
2
Simulation - Natrual Selection
Hi, I've been modelling some data over the past few days, of my work, repeatedly challenging microbes to a certain concentration of cleaner, until the required concentration to inhibit or kill them increaces, at which point they are challenged to a slightly higher concentration each day. I'm doing ths for two different cleaners and I'm collecting the required concentration to kill them as a percentage, the challe...
2003 Nov 01
3
authentication question: pptp tunnels for cisco vpn 3000
I have a Cisco VPN Concentrator 3000, It has the ability to auth PPTP tunnels off of a WinNT Domain controler. Well, I to use my samba3 box instead of a WinNT box. I have samba3 running off of an LDAP back end. Anyway, I setup the VPN Concentrator to auth off of the samba box, and when I test it with the test option, and it works, but when I try to auth a pptp tunnel, it fails saying the
2010 Jan 29
1
How to draw a border for multiple graphs in one page
Hi, I am struggling to create a 2 by 2 multiple graphs in one page. I used par(mfrow=c(2,2)) to divide the screen into 4. In each screen I draw a pie chart (They are all same). For example, my data is like this Concentration value A1 69 A2 8 G1 51 G2 1 G3 68 G4 1 M 17 A1, A2......
2012 May 03
5
Identifying the particular X or Y in a sorted list
Dear All, I have a data sets as shown below A (Patient ID ), B and C are the Concentration of drug in blood on day 1 and day 4, D is the difference in conc. To do this in R I have written a code as follows, identified the number of patients who have more concentration on day 4 . Here I want to identify specifically the patient ID (is he patient 1 or 2 or 5 and 7), whose concentration is...
2010 Aug 11
1
How to calculate the concentration
...'water','soda','soda') value=c(2,3,1,5,7,6) data=data.frame(food,type,value) share=c((2+3)/(2+3+1),5/6,1/6,5/(5+7+6),13/18,13/18) market_con=c(rep(0.8333333^2+0.1666667^2,3),rep(0.2777778^2+0.7222222^2,3)) data$market_con=market_con ###### My problem is how to calculate the concentration (market_con) for different 'food' (1st column). For one food, the concentration is defined as the sum of the squares of share of each type. The concentration is discussed for different foods separately. So it means for the same food, we have the same concentration. As you see in the above...
2007 Nov 28
1
how to find and use specific column after spliting dataframe
Dear all: I am a new R-user and I have 2 questions about it. 1) I need to find specific sub-dataframe, and then use specific column to calculate. For example, after splitting dataframe, I find specific the sub-dataframe, such as ?A.split [1]?. But, I don?t know how to find ?time? and ?concentration? columns of ?A.split [1]?. 2) The equation used to sub-dataframe is (time[i]-time[i-1])*(concentration[i]- concentration[i-1])*1/2. I don?t know how to calculate it. How can I find the specific column and use it to calculate ? x<-rep(c(1.2,6.8),4) y<-rep(c(1, 2),4) z<-rep...
2003 Oct 27
1
Bioassays Yielding concentration-Mortality data
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 untreated control insect...
2010 Feb 09
2
transparent concentric circles
I have a data set which I would like to plot as a set of concentric circles. The data represent a count of the number of characteristics shared by various elements - an example would look like this: 1 100 2 75 3 50 4 25 I.e. all four sets share 25 characteristics, three of them share 50 characteristics, and so on. I would like to plot these as concentric circles, with the circle size
2013 May 21
2
problems with saving plots from loop
Greetings, I cannot find solution for this problem (I was searching on web, but without success): I want to plot dose-response models for one concentration and many responses (lets say 200) and I don?t want to do it manually. So I use loop for this: for (i in mydata[,2:201]){ #first column is concentration pdf(paste("plot_",i,".pdf",sep = "")) plot(i~concentration,log='x') ht <- seq...
2024 Jan 30
2
Use of geometric mean for geochemical concentrations
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 samples will generate the following concentrations: 1, 1/2, 1.4, 1/8, 1/16, ... (or the reciprocal: 1, 2, 4, 8, 16, ...) It makes no sense to compute the arithmetic m...
2011 May 12
1
log transformation and mean question
I have question about log2 transformation and performing mean on log2 data. I am doing analysis for ELISA data. the OD values and the concentration values for the standards were log2 transformed before performing the lm. the OD values for samples were log2 transformed and coefficients of lm were applied to get the log2 concentration values. I then backtransformed these log2 concentrations and the trouble started. when i take the mean of log2 c...
2009 Sep 06
1
Concentration ellipsoid
Hi all, Can anyone please guide me how to draw a Concentration ellipsoid for a bivariate system with a bivariate normal dist. having a VCV matrix : Sigma <- matrix(c(1,2,2,5), 2, 2) I would like to draw in using GGPLOT. Your help will be highly appreciated. Thanks, -- View this message in context: http://www.nabble.com/Concentration-ellipsoid-tp2531570...
2012 May 06
2
how to do the concentration-time profiles in R?
Hi, Dear all, Could you please tell me how to select specified column in dataset and how to do the concentration-time profiles in R? Thank you! xiaoc [[alternative HTML version deleted]]
2005 Feb 05
2
Std Err on Concentration measures
Hi, I'm using the ineq package to calculate some concentration measures (Gini, Herfindal, ...) and I was wondering if there's around also a function to calculate standard error on these measures. If not, is anybody aware of where I can find a reference on this point? Thanks. -- ======================================================== Angelo Secchi...
2011 Jan 05
0
Fwd: Re: Simulation - Natrual Selection
...> To: r-help@r-project.org >>>> Subject: [R] Simulation - Natrual Selection >>>> >>>> Hi, >>>> >>>> I've been modelling some data over the past few days, of my work, >>>> repeatedly challenging microbes to a certain concentration of cleaner, >>>> until the required concentration to inhibit or kill them increaces, at >>>> which point they are challenged to a slightly higher concentration each >>>> day. I'm doing ths for two different cleaners and I'm collecting the >>>&...