31,178 research outputs found
Effect of an External Field on Decoherence
"Decoherence of quantum superpositions through coupling to engineered
reservoirs" is the topic of a recent article by Myatt et al. [Nature
{\underline{403}}, 269 (2000)] which has attracted much interest because of its
relevance to current research in fundamental quantum theory, quantum
computation, teleportation, entanglement and the quantum-classical interface.
However, the preponderance of theoretical work on decoherence does not consider
the effect of an {\underline{external field}}. Here, we present an analysis of
such an effect in the case of the random delta-correlated force discussed by
Myatt et al
On the evaluation of parameter values in models of the water balance
Data of groundwater levels and run-off values of a watershed may occasionally be available together and in sufficiently large amounts that it is worthwhile to try to get as much information on the hydrology of the watershed out of these data as possible. These possibilities are being studied with models of the water balance equation, because run-off is one item on the water balance and groundwater level fluctuations are the result of interplay of all items. In this paper results are discussed of the application of a model of the water balance on data from watersheds in the district of Salland in the province of Overijssel, collected in the years 1970, 1971 and 1972
Globalization and its methodological discontents: Contextualizing globalization through the study of HIV/AIDS
There remains considerable discontent between globalization scholars about how to conceptualize its meaning and in regards to epistemological and methodological questions concerning how we can come to understand how these processes ultimately operate, intersect and transform our lives. This article argues that to better understand what globalization is and how it affects issues such as global health, we must take a differentiating approach, which focuses on how the multiple processes of globalization are encountered and informed by different social groups and with how these encounters are experienced within particular contexts. The article examines the heuristic properties of qualitative field research as a means to help better understand how the intersections of globalization are manifested within particular locations. To do so, the article focuses on three recent case studies conducted on globalization and HIV/AIDS and explores how these cases can help us to understand the contextual permutations involved within the processes of globalization
Maintaining a frozen shipping environment for Phase I clinical trial distribution
The need for stringent temperature control provides significant challenges to pharmaceutical distributors operating in all sectors of the industry. Products with a frozen storage label requirement can be significantly problematic. This study aimed to provide evidence of robust and reproducible frozen shipment arrangements to be operated by a Phase I clinical trial unit. Dry ice was used to achieve a deep frozen internal parcel environment and was tested in a laboratory setting using ultra low temperature loggers within dummy product packs within the test parcels. The laboratory dry ice packing configuration was then repeatedly tested in real time transits using a Glasgow to London delivery schedule. An internal temperature specification was set to not exceed â10 °C during the transport. During each delivery, external temperature monitoring measured the temperature stress experienced by the box in transit. Results demonstrated the ability of the chosen system to not exceed â13.6 °C on average (â10 °C maximum) when exposed to external temperatures of up to +20.1 °C (mean kinetic temperature). The effect was maintained for at least 52.5 h
On the occurrence of growth inhibiting substances in rye
The cause of the decreased food intake and lower growth rate of animals fed on rye was investigated. With rats it was proved that the causative agent was soluble in petroleum ether and acetone. The growth inhibitor was identified as a mixture of 5-n-alkyl resorcinols with odd numbered side-chains of 15-23 C atoms, and of smaller amounts of 5-alkenyl resorcinols.No difference in growth inhibition could be detected from the wheat resorcinols found by Wenckert et al. But the effect of synthetic 5-n-pentadecyl resorcinol was only 50-60 % of that of the grain resorcinols, however. This could not be due to alkenyl resorcinols in wheat and rye, because hydrogenation of the grain resorcinols did not alter the growth inhibition.A fluorometric method for the analysis of 5-alkyl resorcinols was developed. By this method and thin-layer chromatography the alkyl resorcinols could be found in the pericarp. So the resorcinol content of rye proved to be proportional to the surface area of the grain and thus dependent on grain size.Young rats were more susceptible to grain resorcinols than older ones. The decreased food consumption of resorcinol-fed rats was not caused by any unappetizing taste of rye oil or rye resorcinols.The growth of pigs on rations containing 50 % rye oil or an equivalent amount of rye oil, was 11-12% lower than on a 50% barley ration. No differences in harmfulness could be detected between fresh rye and rye stored for a year
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