78,266 research outputs found
Unification for Yukawas and its implications
The supersymmetric finite threshold effects are studied in the presence of
non minimal soft terms that can correct the problematic mass ratios of the
light generations in the minimal SU(5) GUT. We show that with large soft
A-terms, one can achieve simple unification for lighter generations without
additional Higgs multiplet, while having sfermions lighter than 1 TeV. The
presence of such large A-terms will distort the sfermion mass spectrum upon
running from GUT scale down to the electroweak scale making it distinct from
the universal SUSY breaking scenarios, especially in the first two generations.
The implications of these splittings are studied in K and D meson oscillations
and in rare processes D^+ -> pi^+ nu anti-nu and K^+ -> pi^+ nu anti-nu, and in
the latter case the effect is found to be important.Comment: 4 pages, based on a talk given at SUSY 09, 5-10 Jun 200
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A THEORY OF THE CORRUPT KEYNESIAN
AbstractWe evaluate the impact of real business cycle shocks on corruption and economic policy in a model of entry regulation in a representative democracy. We find that corruption is pro-cyclical and regulation policy is counter-cyclical. Corrupt politicians engage in excessive stabilization of aggregate fluctuations and behave as if they were Keynesian. We also find that business cycle shocks can induce political instability with politicians losing office in recessions
Investigation on rotating ailerons
The effectiveness of rotating ailerons in a subsonic flow is theoretically studied to evaluate their capability in comparison to conventional ailerons. The analysis is based on the cortex lattice approach of Byelotserkovskii (1965) for different wing planforms of small and large aspect ratios. The rolling moment coefficient obtained with the rotating ailerons with a span equal to 22% of the wing span is higher than that for the conventional ailerons of almost double the span. The effectiveness of the rotating ailerons decreases with reduction in the wing aspect ratio, although it is possible to reduce the aileron size for required rolling capabilit
An improved \eps expansion for three-dimensional turbulence: two-loop renormalization near two dimensions
An improved \eps expansion in the -dimensional () stochastic
theory of turbulence is constructed at two-loop order which incorporates the
effect of pole singularities at in coefficients of the \eps
expansion of universal quantities. For a proper account of the effect of these
singularities two different approaches to the renormalization of the powerlike
correlation function of the random force are analyzed near two dimensions. By
direct calculation it is shown that the approach based on the mere
renormalization of the nonlocal correlation function leads to contradictions at
two-loop order. On the other hand, a two-loop calculation in the
renormalization scheme with the addition to the force correlation function of a
local term to be renormalized instead of the nonlocal one yields consistent
results in accordance with the UV renormalization theory. The latter
renormalization prescription is used for the two-loop renormalization-group
analysis amended with partial resummation of the pole singularities near two
dimensions leading to a significant improvement of the agreement with
experimental results for the Kolmogorov constant.Comment: 23 pages, 2 figure
Communities and patterns of scientific collaboration
This is the author's accepted version of this article deposited at arXiv (arXiv:1006.1788v2 [physics.soc-ph]) and subsequently published in Scientometrics October 2011, Volume 89, Issue 1, pp 381-396. The final publication is available at link.springer.com http://link.springer.com/article/10.1007%2Fs11192-011-0439-1Author's note: 17 pages. To appear in special edition of Scientometrics. Abstract on arXiv meta-data a shorter version of abstract on actual paper (both in journal and arXiv full paper17 pages. To appear in special edition of Scientometrics. Abstract on arXiv meta-data a shorter version of abstract on actual paper (both in journal and arXiv full paper version)17 pages. To appear in special edition of Scientometrics. Abstract on arXiv meta-data a shorter version of abstract on actual paper (both in journal and arXiv full paper version)17 pages. To appear in special edition of Scientometrics. Abstract on arXiv meta-data a shorter version of abstract on actual paper (both in journal and arXiv full paper version)17 pages. To appear in special edition of Scientometrics. Abstract on arXiv meta-data a shorter version of abstract on actual paper (both in journal and arXiv full paper version)This paper investigates the role of homophily and focus constraint in shaping collaborative scientific research. First, homophily structures collaboration when scientists adhere to a norm of exclusivity in selecting similar partners at a higher rate than dissimilar ones. Two dimensions on which similarity between scientists can be assessed are their research specialties and status positions. Second, focus constraint shapes collaboration when connections among scientists depend on opportunities for social contact. Constraint comes in two forms, depending on whether it originates in institutional or geographic space. Institutional constraint refers to the tendency of scientists to select collaborators within rather than across institutional boundaries. Geographic constraint is the principle that, when collaborations span different institutions, they are more likely to involve scientists that are geographically co-located than dispersed. To study homophily and focus constraint, the paper will argue in favour of an idea of collaboration that moves beyond formal co-authorship to include also other forms of informal intellectual exchange that do not translate into the publication of joint work. A community-detection algorithm is applied to the co-authorship network of the scientists that submitted in Business and Management in the 2001 UK RAE. While results only partially support research-based homophily, they indicate that scientists use status positions for discriminating between potential partners by selecting collaborators from institutions with a rating similar to their own. Strong support is provided in favour of institutional and geographic constraints. Scientists tend to forge intra-institutional collaborations; yet, when they seek collaborators outside their own institutions, they tend to select those who are in geographic proximity
Phosphomannosyl receptors may participate in the adhesive interaction between lymphocytes and high endothelial venules.
Normal and malignant lymphocytes can migrate from the bloodstream into lymph nodes and Peyer's patches. This process helps distribute normal lymphocytes throughout the lymphoid system and may provide a portal of entry for circulating malignant cells. An adhesive interaction between lymphocytes and the endothelium of postcapillary venules is the first step in the migratory process. We have recently shown that the simple sugars L-fucose and D-mannose, and an L-fucose-rich polysaccharide (fucoidin), can inhibit this adhesive interaction in vitro. We now report that mannose-6-phosphate, the structurally related sugar fructose-1-phosphate, and a phosphomannan, core polysaccharide from the yeast Hansenula holstii (PPME) are also potent inhibitors. Inhibitory activity was assessed by incubating freshly prepared suspensions of lymphocytes, containing the various additives, over air-dried, frozen sections of syngeneic lymph nodes at 7-10 degrees C. Sections were then evaluated in the light microscope for the binding of lymphocytes to postcapillary venules. Mannose-6-phosphate and fructose-1-phosphate were potent inhibitors of lymphocyte attachment (one-half maximal inhibition at 2-3 mM). Mannose-1-phosphate and fructose-6-phosphate had slight inhibitory activity, while glucose-1-phosphate, glucose-6-phosphate, galactose-1-phosphate, and galactose-6-phosphate had no significant activity (at 10 mM). In addition, the phosphomannan core polysaccharide was a potent inhibitor (one-half maximal inhibition at 10-20 micrograms/ml); dephosphorylation with alkaline phosphatase resulted in loss of its inhibitory activity. Preincubation of the lymphocytes, but not the lymph node frozen sections, with PPME resulted in persistent inhibition of binding. Neither the monosaccharides nor the polysaccharide suppressed protein synthesis nor decreased the viability of the lymphocytes. Furthermore, inhibitory activity did not correlate with an increase in negative charge on the lymphocyte surface (as measured by cellular electrophoresis). These data suggest that a carbohydrate-binding molecule on the lymphocyte surface, with specificity for mannose-phosphates and structurally related carbohydrates, may be involved in the adhesive interaction mediating lymphocyte recirculation
Preparation of pure boehmite, alpha-Al2O3 and their mixtures by hydrothermal oxidation of aluminium metal
A hydrothermal oxidation process for preparing pure boehmite, alpha-Al2O3, and their mixtures by oxidation of pure aluminum metal is described, and the reaction mechanisms involved are identified. SEM images are presented which show distinct morphologies of boehmite, alpha-Al2O3, and boehmite + alpha-Al2O3 phases. Near sperical shapes of alpha-Al2O3 powder phases are obtained at 550 C with 30 percent volume of fill
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