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Start Over Coverage 245-248

1. Effect of photoinhibitory treatments on photosystem 2 at low temperature studied by thermoluminescence

Creator:
Briantais, J. M., Ducruet, J. M., Hodges, M., and Krause, G. H.
Format:
print
Type:
model:internalpart and TEXT
Language:
Multiple languages
Description:
The effect of the low temperature acclimation and photoinhibitory treatment on photosystem 2 (PS 2) of the cold-unhardened and -hardened spinách leaves were studied by thermoluminescence emission. Acclimation as well as photoinhibition at 4 °C rose inactive PS 2 reaction centres which did not produce thermoluminescence.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Examination of solar radio burst onsets in view of different flare scenarios and preflare structures

Creator:
Krüger, A., Auraß, H., Kliem, B., and Urpo, S.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astrophysics, released energy, and flare development
Language:
Czech
Description:
The time profiles of the solar microwave emission exhibit various phenomona reflecting the evolution of magnetic flux tubes before and during the onset of flare events. Different scenarios are posslble to describe the processes of energy release in a flux tube and the interaction of a number of tubes during the preflare stage and the early flare development, Multi-peak structures at quite different time scales displayed by flux records at mm-, cm-, and dm-waves are examined; they rise the question how to distinguish between repeated energy release at one site and the propagation of the flare disturbances over an extended source area, A discussion of observed time scales and released energy in the frame of some scenarios is carried out.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

4. Proton microprobe analysis of interplanetary dust particles

Creator:
Wallenwein, R., Antz, Ch., Jessberger, E. K., and Traxel, K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
proton microprobe and interplanetary dust particles
Language:
Czech
Description:
Comets and asteroids are thought to be the main sources of interplanetary dust particles (IDPs). IDPs with a diameter < 50 um are able to survive the entry into the Earth's atmosphere, where they can be collected without destruction. Because of their small size and mass, typically <10 um and <10~^9 g, their chemical analysis iscdifficult. We introduce the proton microprobe for the non-destructive detection of trace elemente in IDPs. Using the Heidelberg proton microprobe which provides a beam spot of < 2x3 um^2, four IDPs have been analyzed and up to 26 elements were detected. To quantitatively evaluate the proton-induced X-ray spectra we calculated ab initio Xray yields for the samples. Most elemental abundance ratios in three IDPs agree within a factor of two with those of cosmic abundance but with the notable exception of some volatile elements (P, Cu, Ga, Br, and Zn) which are strongly enriched. This is contrasting one IDP in which Ca and the volatile elemente K, Zn and S are depleted.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public