15,729 research outputs found
An inequality of Kostka numbers and Galois groups of Schubert problems
We show that the Galois group of any Schubert problem involving lines in
projective space contains the alternating group. Using a criterion of Vakil and
a special position argument due to Schubert, this follows from a particular
inequality among Kostka numbers of two-rowed tableaux. In most cases, an easy
combinatorial injection proves the inequality. For the remaining cases, we use
that these Kostka numbers appear in tensor product decompositions of
sl_2(C)-modules. Interpreting the tensor product as the action of certain
commuting Toeplitz matrices and using a spectral analysis and Fourier series
rewrites the inequality as the positivity of an integral. We establish the
inequality by estimating this integral.Comment: Extended abstract for FPSAC 201
Involvement and use of multiple search channels in the automobile purchase process
In this study we investigate the relationship between involvement and use of multiple search channels in the case of pre-purchase information search for automobiles. We derive theoretical hypotheses by combining arguments from both an economic or cost/benefit approach and a motivational perspective. Our theoretical framework is tested on a sample of 1392 Dutch consumers using a structural equation model approach. We find that interpersonal sources and retailers are relatively often consulted and their use is not strongly related to involvement. The use of channels such as the World Wide Web and mass media is instead strongly related to involvement, because their specialized content is best appreciated by highly involved consumers. Finally, theoretical and managerial implications are discussed.car purchase, involvement, pre-purchase information search
Consumer Car Preferences and Information Search Channels
In this paper, we measure the relations between stated and revealed car preferences and the use of information sources in the car purchasing process, based on a survey of households in the Netherlands. The analysis showed that attitudinal and behavioral constructs are found for âenvironmentalâ, âperformanceâ, and âconvenienceâ preferences, but that there is a âgapâ between attitude and behavior. The results show that people with a positive environmental attitude who also show environmentally friendly behavior have more involvement with cars than people who do not translate their environmental attitude into the corresponding behavior. This leads to the idea that not only environmental knowledge but also involvement with cars is a prerequisite for buying an environmentally friendly car.car purchase, involvement, attitudeâbehavior gap, information search
Role of intermediate water variability in the Caribbean and Gulf of Mexico in deglacial climate change
Interactive Problem Structuring with ICZM Stakeholders
Integrated Coastal Zone Management (ICZM) is struggling with a lack of science-management integration. Many computer systems, usually known as âdecision support systemsâ, have been developed with the intention to make scientific knowledge about complex systems more accessible for coastal managers. These tools, allowing a multi-disciplinary approach with multi-criteria analyses, are designed for well-defined, structured problems. However, in practice stakeholder consensus on the problem structure is usually lacking. Aim of this paper is to explore the practical opportunities for the new so-called Quasta approach to structure complex problems in a group setting. This approach is based on a combination of Cognitive Mapping and Qualitative Probabilistic Networks. It comprehends a new type of computer system which is quite simple and flexible as well. The tool is tested in two workshops in which various coastal management issues were discussed. Evaluations of these workshops show that (1) this system helps stakeholders to make them aware of causal relationships, (2) it is useful for a qualitative exploration of scenarios, (3) it identifies the quantitative knowledge gaps of the problem being discussed and (4) the threshold for non technicians to use this tool is quite low.Integrated Coastal Zone Management, Problem Structuring, Stakeholder Participation, Cognitive Mapping, Interactive Policy Making
Differential Tissue Response to Growth Hormone in Mice
Growth hormone (GH) has been shown to act directly on multiple tissues throughout the body. Historically, it was believed that GH acted directly in the liver and only indirectly in other tissues via insulinâlike growth hormone 1 (IGFâ1). Despite extensive work to describe GH action in individual tissues, a comparative analysis of acute GH signaling in key metabolic tissues has not been performed. Herein, we address this knowledge gap. Acute tissue response to human recombinant GH was assessed in mice by measuring signaling via phosphoâSTAT5 immunoblotting. STAT5 activation is an easily and reliably detected early marker of GH receptor engagement. We found differential tissue sensitivities; liver and kidney were equally GHâsensitive and more sensitive than white adipose tissue, heart, and muscle (gastrocnemius). Gastrocnemius had the greatest maximal response compared to heart, liver, white adipose tissue, and whole kidney. Differences in maximum responsiveness were positively correlated with tissue STAT5 abundance, while differences in sensitivity were not explained by differences in GH receptor levels. Thus, GH sensitivity and responsiveness of distinct metabolic tissues differ and may impact physiology and disease
SWAS observations of comet 9P/Tempel 1 and Deep Impact
On 4 July 2005 at 1:52 UT the Deep Impact mission successfully completed its
goal to hit the nucleus of 9P/Tempel 1 with an impactor, forming a crater on
the nucleus and ejecting material into the coma of the comet. The 370 kg
impactor collided with the sunlit side of the nucleus with a relative velocity
of 10.2 km/s. NASA's Submillimeter Wave Astronomy Satellite (SWAS) observed the
1(10)-1(01) ortho-water ground-state rotational transition in comet 9P/Tempel 1
before, during, and after the impact. No excess emission from the impact was
detected by SWAS. However, the water production rate of the comet showed large
natural variations of more than a factor of three during the weeks before the
impact.Comment: to appear in the proceedings of the IAU Symposium No. 231:
"Astrochemistry - Recent Successes and Current Callenges". Typo corrected in
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