725 research outputs found
Evaluation of the ALMA Prototype Antennas
The ALMA North American and European prototype antennas have been evaluated
by a variety of measurement systems to quantify the major performance
specifications. Nearfield holography was used to set the reflector surfaces to
17 microns RMS. Pointing and fast switching performance was determined with an
optical telescope and by millimeter wavelength radiometry, yielding 2 arcsec
absolute and 0.6 arcsec offset pointing accuracies. Path length stability was
measured to be less than or approximately equal to 20 microns over 10 minute
time periods using optical measurement devices. Dynamical performance was
studied with a set of accelerometers, providing data on wind induced tracking
errors and structural deformation. Considering all measurements made during
this evaluation, both prototype antennas meet the major ALMA antenna
performance specifications.Comment: 83 pages, 36 figures, AASTex format, to appear in PASP September 2006
issu
Class Position of Immigrant Workers in a Post-Industrial Economy: The Dutch Case
In this paper, the issue of changing labour-market opportunities and the position of members
of minority groups in advanced service economies is addressed, focusing on the Dutch case.
We distinguish between two social hierarchies, one of traditional ‘fordist’ occupations and
one of post-fordist occupations. Compared to the native Dutch, all immigrant groups are
over-represented at the bottom of the labour market, both in the fordist and in the postindustrial
hierarchy. Increased immigrant labour-market participation in the 1990s was
accompanied by a strong rise in the number of flexible labour contracts. Native Dutch also
work more frequently on flexible labour contracts, but not to the same extent as immigrants.
The lower occupational level of the Surinamese, Antilleans and other non-Western
immigrants employed in post-industrial occupations can be attributed to their low
educational level. This is not true, however, for Turks, Moroccans and other non-Western
immigrants employed in fordist occupations. Their low occupational level can not be
completely explained by their low educational level. The effects of changes in the economic
structure differ for ethnic groups, depending on their past employment, their cultural capital
and the institutional framework in which they have to operate
Роль совершенствования бухгалтерского учета в управлении производственными запасами
Целью проведения исследования является обоснование направлений повышения эффективности использования материальных производственных запасов на предприятии в условиях рыночной экономики
Bioinformatic Inference of Specific and General Transcription Factor Binding Sites in the Plant Pathogen Phytophthora infestans
Plant infection by oomycete pathogens is a complex process. It requires precise expression of a plethora of genes in the pathogen that contribute to a successful interaction with the host. Whereas much effort has been made to uncover the molecular systems underlying this infection process, mechanisms of transcriptional regulation of the genes involved remain largely unknown. We performed the first systematic de-novo DNA motif discovery analysis in Phytophthora. To this end, we utilized the genome sequence of the late blight pathogen Phytophthora infestans and two related Phytophthora species (P. ramorum and P. sojae), as well as genome-wide in planta gene expression data to systematically predict 19 conserved DNA motifs. This catalog describes common eukaryotic promoter elements whose functionality is supported by the presence of orthologs of known general transcription factors. Together with strong functional enrichment of the common promoter elements towards effector genes involved in pathogenicity, we obtained a new and expanded picture of the promoter structure in P. infestans. More intriguingly, we identified specific DNA motifs that are either highly abundant or whose presence is significantly correlated with gene expression levels during infection. Several of these motifs are observed upstream of genes encoding transporters, RXLR effectors, but also transcriptional regulators. Motifs that are observed upstream of known pathogenicity-related genes are potentially important binding sites for transcription factors. Our analyses add substantial knowledge to the as of yet virtually unexplored question regarding general and specific gene regulation in this important class of pathogens. We propose hypotheses on the effects of cis-regulatory motifs on the gene regulation of pathogenicity-related genes and pinpoint motifs that are prime targets for further experimental validation
Tyrosine phosphorylation profiling in FGF-2 stimulated human embryonic stem cells
10.1371/journal.pone.0017538PLoS ONE63
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