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Notes on drift theory
It is shown that there is a simpler way to derive the average guiding center drift of a distribution of particles than via the so-called single particle analysis. Based on this derivation it is shown that the entire drift formalism can be considerably simplified, and that results for low order anisotropies are more generally valid than is usually appreciated. This drift analysis leads to a natural alternative derivation of the drift velocity along a neutral sheet
The mineralization of commercial organic fertilizers at 8°C temperature
In organic production only organic fertilizers and soil conditioners can be used to supply
the soil with nitrogen. The mineralization of these products is slow and so there can be
problems with the supply of nitrogen, when the demand of the plants is high. The supply of
nitrogen from organic products depends on the speed of their mineralization which is
primarily influenced by the composition and formulation of their raw material.
In apple production in the Alps-region especially during spring problems with nitrogen
supply are common. In that period, the weather conditions are sometimes bad, the
temperature in the soil is low and mineralization starts slowly - apple trees demand more
nitrogen than the soil can deliver.
To compensate the demand of the apple tree organic growers can not use mineral
fertilizers but only organic fertilizers and soil conditioners whose mineralization rate is often
unknown. There is a strong need in organic fruit production to receive more information
about the behaviour of fertilizers in the soil especially concerning their N-release under
different conditions.
To acquire that information, incubation experiments under controlled conditions
(temperature, type of soil, humidity of the soil) were carried out in the laboratory to
determine the mineralization-rate of different organic fertilizers and soil conditioners which
are available in our region
Direct comparison of the performance of CZT detectors contacted with various metals
Cadmium Zinc Telluride (CZT) achieves excellent spatial resolution and good
energy resolution over the broad energy range from several keV into the MeV
energy range. In this paper we present the results of a systematic study of the
performance of CZT detectors manufacturered by Orbotech (before IMARAD)
depending on surface preparation, contact materials and contact deposition. The
standard Orbotech detectors have the dimension of 2.0 x 2.0 x 0.5 cm. They have
a pixellated In anode with 8 x 8 pixels and a monolithic In cathode. Using the
same CZT substrates several times, we have made a direct comparison of the
performance of different contact materials by replacing the cathode and/or the
anode contacts with several high-workfunction metals. We present the
performance of the detectors and conclude with an overview over our ongoing
detector optimization.Comment: 8 pages, 5 figures, to appear in the proceedings of the conference
5922, "Hard X-Ray and Gamma-Ray Detector Physics VII" on the "Optics &
Photonics 2005" SPIE Symposium, July 31- August 4, 2005, San Diego, C
Labor markets and labor allocative efficiency among farm households in western Kenya
This paper evaluates how efficiently farm households allocate labor between farm and offfarm activities. It estimates farm and off-farm labor supply functions to determine the factors that influence labor allocation. Both the shadow wage and the off-farm wage rate are included as regressors in the supply functions. The study reveals that, on average, farm households are inefficient, but when linked to labor markets their productivity and internal efficiency increase. The decision to sell labor is influenced by location, and off-farm employment is difficult to find, particularly for the better educated. Interventions should aim to increase opportunities for off-farm employment for persons with skills or with higher than the basic level of education, and to reduce the cost of participating in labor markets, for example by improving rural infrastructure. Addressing failures in rural financial markets would save poor households from having to sell their labor for less than they get from their farm
Mutual Event Observations of Io's Sodium Corona
We have measured the column density profile of Io's sodium corona using 10 mutual eclipses between the Galilean satellites. This approach circumvents the problem of spatially resolving Io's corona directly from Io's bright continuum in the presence of atmospheric seeing and telescopic scattering. The primary goal is to investigate the spatial and temporal variations of Io's corona. Spectra from the Keck Observatory and McDonald Observatory from 1997 reveal a corona that is only approximately spherically symmetric around Io. Comparing the globally averaged radial sodium column density profile in the corona with profiles measured in 1991 and 1985, we find that there has been no significant variation. However, there appears to be a previously undetected asymmetry: the corona above Io's sub-Jupiter hemisphere is consistently more dense than above the anti-Jupiter hemisphere
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