search for: chemical

I am just starting to code in R and need some help as I am used to doing this in SAS. I have a dataset that looks like this: Chemical Well1 Well2 Well3 Well4 BOD 13.2 14.2 15.5 14.2 O2 7.8 2.6 3.5 2.4 TURB 10.2 14.6 18.5 17.3 and so on with more chemicals.... I would like to transpose my data so that it looks like this: Chemical WellID Value BOD Well1 13.2 BOD Well2 14.2 BOD Well3 15.5 BOD Well4 14.2 O2 Well1 7.8 O2 Well2 2.6 .....

Greetings - I am working on some data that contain chemical names with air concentrations, and I am creating a data frame with date/time and each chemical having its own column. However, these are organic chemicals (e.g. 1-butene, 2,3,4-trimethylbenzene etc). The package I am going to be using the data with is openair, and many of the great functions requir...

Dear ?, I'm sure that there are many ways to do what you want; here's one: > cbind(concept_df, category= + ifelse(apply( + sapply(chemical_df$chemical, + function(x) grepl(x, concept_df$concept)), + 1, any), + "chemical", "")) concept category 1 butan acid chemical 2 nano diamond particl 3 slurri composit 4 composit ph polis...

Dear list, I am using R 2.1.1 on a Fedora 3 Linux, 32 bit PC. If I compute the aggregated mean and the standard deviation I get standard deviation values for factors where the mean was not computed. It seems to me that this is somehow related to the NA values. But I don't quite understand what is going wrong? Could it be related to the data import already? Some of the imported data got the

Hi - I'm just starting out with R and have come up against a problem with what should be a simple operation. I'm plotting a range of safety standards for 7 different chemicals. I don't want the standard box and whisker plot - I just a dot for each value. Whilst using "plot.default" I get the error "invalid xlim value" - which is confusing since using the same script with "plot" does not produce this error. However, I do notice that only...

Folks, This is so simple is driving me crazy. It's not really an R question is more an Statistics question. I applied a chemical in 3 different events during a growing season. I took 3 samples in each event to estimate mean applied chemical. Thus, I can easily estimate means and st.err by event. I can then estimate the total chemical applied for the whole season by adding the 3 means for each event. How can I estimate th...

in some other language have a concept e.i "auto postback" So, in Ruby on rails is there any such option e.i "auto postback" or same as "auto postback" basically what i want ot do is that i have 2 select box One for "Industry" and other for "Chemical" 1st we show all the industry in "Industry" select box. if we select any 1 industry from there, then the corrosponding chemicals will b shown in the "chemical" select box... please help me any one.... THankx --~--~---------~--~----~------------~-------~--~----~ You rec...

Greetings, I have a question that I'd like to get input on. I have a classic toxicology study where I artificially fertilized and exposed embryos to a chemical and counted defects. In addition, I kept track of male-female pairs that I used to artificially fertilize and generate embryos with. I need to use logistic regression to model the response, but also check that the genetics of the pairings did or did not have an effect on the response. My data looks...

We are reading big tables, such as, Chemicals <- read.table('ftp://ftp.bls.gov/pub/time.series/wp/wp.data.7.Chemicals',header = TRUE, sep = '\t', as.is =T) I was wondering if it is possible to set a filter during loading so that we just load what we want not the whole table each time. Thanks, -james

How do I post text-string dates along the x-axis instead of the excel_date position values? I would like to plot a time-series of chemical values changing with time The first column is the internal date from excel. This should be the x-axis position of a graph of the plotted data. The second column is a text-string of date. This should be what is posted (instead of the excel_date). The third column is the chemical data and this sho...

Hi I'm looking for a package to perform quality control, normalization and analysis of high throughput cell-base chemical screens. I know that the cellHTS2 package provides this for siRNA screens. Does anybody know if something like what I'm looking for exists? Thank you! Gabriele Zoppoli, MD Ph.D. Fellow, Experimental and Clinical Oncology and Hematology, University of Genova, Genova, Italy Guest Researcher,...

Hello R Folks... I've been looking around the 'net and I see many complex solutions in various languages to this question, but I have a pretty simple need (and I'm not much good at regex). I want to use a chemical formula as a function argument. The formula would be in "Hill order" which is to list C, then H, then all other elements in alphabetical order. My example will have only a limited number of elements, few enough that one can search directly for each element. So some examples wou...

Dear All, I hope this is not too off-topic. Essentially, I need to know if there is any R package which can help me with a deformulation project. Suppose e.g. that you know from a chemical analysis the fat, mineral, vitamin, energy [and so on] content of a certain food product. You also know the ingredients of this product (e.g. milk, lactose, vegetable oil) and you know the chemical composition of each ingredient in terms of fat, minerals, vitamins etc... At this point the que...

Dear colleagues, I often use chemical formulas to label my x-axis, e.g. in barplots. I used to do this like the following example and it worked just fine: a <- seq(2,24,2) b <- seq(3,36,3) c <- rbind(a,b) barplot(c, width=c(0.9, 1.1),space=c(0.2, 0.75), col=c("indianred4", "yellow2"), beside = TRUE, xlab=...

Dear colleagues, I often use chemical formulas to label my x-axis, e.g. in barplots. I used to do this like the following example and it worked just fine: a <- seq(2,24,2) b <- seq(3,36,3) c <- rbind(a,b) barplot(c, width=c(0.9, 1.1),space=c(0.2, 0.75), col=c("indianred4", "yellow2"), beside = TRUE, xlab=...

I have two data frame. I want to use "chemical_df" to match "concept_df " concept_df <- data.frame(concept=c("butan acid ", "nano diamond particl", "slurri composit", "composit ph polis", " inorgan particl ", "grind liquid", "liquid formul", "nanopar...

Try the stringr package. This should work chemical=c("basic", "alkalin", "alkali", "acid", " ph ", "hss") chemical_match <- str_c(chemical, collapse = "|") chemical_match concept_df$match[str_detect(concept_df$concept, chemical_match)] <- "chemical" concept_df...

I need to understand how and why dcast() adds NAs to a data frame that contained no missing values. The database table of chemical concentrations has all missing values removed because they cannot contribute to data analyses. The structure of the R data frame of these data have no NA values, and neither does the data frame resulting from applying the reshape2 melt() function to it. However, the data frame produced by the dcast...

Hi all, I'm wondering if there's a way that I can perform McNemar's test for a small dataset easier. I know this may be different from the usual way, but I'm hoping to throw it out there for help. For now, my orginnal dataset looks something like this... Chemical shifts Pre_yes Pre_no Post_yes Post_no 1 20 23 30 13 2 22 21 11 32 3 30 13 40 3 ...... so p...

...ic, but with garlic, not dettol. "EV.Dettol" is E.coli that has been evolved against dettol, and then tested afterwards against dettol to get the "dead zones". Same applies for "EV.Garlic" but with garlic). You see from the four levels (or treatments) there are two chemicals involved. So my first concern is whether they should be analysed using two seperate ANOVA's. NE.Dettol and NE.Garlic are both the same organism - a lab stock E.coli, just exposed to two different chemicals. EV.Dettol and EV.Garlic, are in principle, likely to be two different forms of the...