## Thesis topic: Light dependent stomatal osmoregulation

We have a thesis topic available as part of our Academy of Finland project on the acclimation of stomatal opening responses to light. It is suitable for a M.Sc. thesis (Gradu) in Plant Biology with both ecological and physiological emphasis. The student’s work would be supervised by Pedro J. Aphalo, Kurt Fagerstedt, and Fang Wang. Thesis could be written either in English, Finnish, or even Swedish.

More details at: http://blogs.helsinki.fi/senpep-blog/joining/459-2/

## All photobiology R packages work under R 3.1.0 RC

Yesterday I checked that all the photobiology R packages work with the new version of R to be released on 10 April. No .zip files are available yet, but the source distributions install without errors.

## photobiologyUV updated to 0.2.5

Version 0.2.5 has no changes in functionality already available in version 0.2.4. The new versio adds a new “waveband” and related functions for the BSWF for methane production from pectin of McLeod et al. (2008).

## data.table := an improved data.frame

I started using a package called data.table just yesterday. I re-wrote the whole of the MayaCalc package to use data.table instead of data.frame. Got it working in a few hours. Syntax is clearer and very concise. As a bonus everything should execute much faster (x10 to x30). I will time MayaCalc today after checking that the results are o.k.
Documentation for data.table is a bit terse, I will write some examples here in a few days’ time.

Be aware though that the semantics is really different when used as an argument to a function. If you use the := operator you achieve the equivalent of passing the data.table argument by REFERENCE rather than the normal R convention of passing all arguments by COPY. This is much faster for large data tables as copying is avoided, but you should be careful even if you understand the difference between these two semantics. If you don’t, do not use data.table before you fully understand the difference and all its implications.