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Update on the spectroradiometer

Our new Maya 2000 Pro is back at Lasse Ylianttila’s lab for calibration with the new Bentham D7-H-SMA cosine diffuser. We will get it back soon. We have been in touch with Ocean Optics about the bad stray light performance. They think that one reason for this is that our instrument has the HC-1 grating with a very wide spectral measuring range of 200 to 1100 nm. For our planned measurements we do need a range of at least 250 to 900 nm, but they think that UV-B performance would have been better with a grating with the upper limit at 650 nm. The problem can be overcome by measuring the stray light using an UV blocking filter, but this adds one more step to each measurement. As we do need to measure both UV and visible radiation probably there would not be any better instrument available, at least from Ocean Optics, for doing our measurements. However, for measuring UV-B alone this is not the handiest instrument.

We expect to start using the Maya in a few weeks time to measure sunlight outdoors and in greenhouses, and later on within plant canopies. Measuring spectra and temporal variation of light quality within canopies could be an interesting MSc thesis project. Please, contact me if you are interested.

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Promising new front end for R “RStudio”

I just installed this program, and did a test run. Looks great for beta software. Replaces the whole R GUI. I am especially interested in Sweave support that is rather flaky in Tinn-R or requires a lot of setting changes in WinEdt. I will write again after some more testing. It is available for download at http://rstudio.org/ where there is also some documentation.

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Update on the spectroradiometer

Lasse Ylianttila has now developed an stray light correction algorithm for our Ocean Optics Maya 2000 Pro, and done the necessary calibrations and slit function measurements with different lasers. Developing an stray light correction for the Maya was more complex as, unexpectedly, this top-of-the-range model behaved worse with respect to stray light than the cheaper and older Ocean Optics S2000. We are still waiting for the Bentham cosine diffuser to be delivered, but meanwhile Lasse has lent us an Ocean Optics diffusser. The spectral irradiance calibration will need to be repeated when we get our own diffuser.

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COST action UV4growth conference in Szeged, Hungary

Matt, Luis, Lasse Ylianttila and myself participated in this meeting. All of us gave talks, and Lasse and myself taught at the worshop for ESRs on the day after the conference ended. The management committee (MC) meeting was on Monday. I took over from Lars Olof Björn the coordination of TG 1 “UV technology”. Lars Olof stepped down as leader for personal reasons. Lars Olof will replace me as assistant leader. Because I am now leader of TG 1, I stepped down as leader of working group 3 (WG3) and will be replaced by Riitta Julkunen-Titto.

There were about 100 participants in the conference (7 or 8 from Finland), including many of the most prominent researchers working on the effects of UV on plants. We made many contacts and had very interesting discussions. From the data presented in several talks, it is now clear that UVR8 is almost for sure the UV-B photoreceptor in plants.

In the conference Lasse talked about the calibrations and stray light corrections needed to take UV measurements with array spectrometers. He presented data from STUK’s Ocean Optics S2000 and our Ocean Optics Maya 2000 Pro. Matt presented his data on Nothofagus (both from his experiments in Tierra del Fuego and in Viikki). Luis presented some results on epidermal transmittance measured in Arabidopsis with our Dualex 3 FLAV. I presented our work on action spectra, from Titta’s, Luis’s and Sari’s experiments.

In the workshop Lasse gave a lecture on the pitfalls that one can run into when measuring UV-B. I gave a lecture on biological spectral weighting functions, biologically effective doses, and how to compare doses of UV from lamps and the sun. For the workshop practicals we took the Dualex and the Maya spectrometer to Szeged.

Szeged is a nice city and we managed to wander through the old city in spite of the packed conference programme. None of us took a camera to Szeged so we have no photos to post.

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Spam

Lately I have been getting a flood of spam comments. A lot were filtered by the anti-spam tools, but I was getting something like 20 comments to moderate per day. I decided to stop this by allowing comment writing only by logged-in users. So if you want to post a comment, please, remember to login first.

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Annual meeting of the “uv4growth” COST action

The first annual meeting of the COST action on plants and UV-B will take place on 6-9 February 2011 in Szeged, Hungary. Please, submit your abstracts as soon as possible, especially if you want to qualify for a reimbursement of travel expenses. The web site of the conference is already live, please register if you plan to participate. Payment of the registration fee can be done later.