3,155 research outputs found
Heavy neutralino relic abundance with Sommerfeld enhancements - a study of pMSSM scenarios
We present a detailed discussion of Sommerfeld enhancements in neutralino
dark matter relic abundance calculations for several popular benchmark
scenarios in the general MSSM. Our analysis is focused on models with heavy
wino- and higgsino-like neutralino LSP and models interpolating between these
two scenarios. This work is the first phenomenological application of effective
field theory methods that we have developed in earlier work and that allow for
the consistent study of Sommerfeld enhancements in non-relativistic neutralino
and chargino co-annihilation reactions within the general MSSM, away from the
pure-wino and pure-higgsino limits.Comment: 38 pages, 14 figures, 3 table
Non-relativistic pair annihilation of nearly mass degenerate neutralinos and charginos I. General framework and S-wave annihilation
We compute analytically the tree-level annihilation rates of a collection of
non-relativistic neutralino and chargino two-particle states in the general
MSSM, including the previously unknown off-diagonal rates. The results are
prerequisites to the calculation of the Sommerfeld enhancement in the MSSM,
which will be presented in subsequent work. They can also be used to obtain
concise analytic expressions for MSSM dark matter pair annihilation in the
present Universe for a large number of exclusive two-particle final states.Comment: LATeX, 24 pages (+ 25 pages Appendix), 11 figures; v2 - replaced
incorrect version of Fig. 4 and fixed typos listed in the JHEP erratu
Blood pressure and indices of glomerular filtration area in hypertensive and normotensive Prague rats
The involvement of the kidney in the pathogenesis of hypertension has long been recognised, although the specific renal mechanisms underlying this phenomenon are still unknown. A current hypothesis attributes hyper tension to a reduction in glomerular filtration area by glomerular loss, The present study analyses the relationship between glomerular number and volume and conscious systolic blood pressure (SBP) in 4- to 53-week-old hypertensive (PHR) and normotensive (PNR) rats of the Prague strain. Adult PHRs had higher SEP, were larger and had larger kidneys than PNRs, but 20% fewer glomeruli, A significant negative correlation between SEP and glomerular number was found in PHR males, but not in PHR females or PNRs. There was no correlation at all between glomerular volume and SEP and, in young animals, both SEP and glomerular number were higher in PHRs than in PNRs. In addition, in adult PHRs, glomerular volume and SEP were higher in males than in females. In summary, a generally valid, causal relation-ship linking raised blood pressure to decreased glomerular number or volume could not be demonstrated in the Prague rat model of genetically determined hypertension. The nature of the renal mechanism(s) determining the hypertension in this model remains unknown. Copyright (C) 2000 S. Karger AG, Basel
Density of automorphic points in deformation rings of polarized global Galois representations
Conjecturally, the Galois representations that are attached to essentially
selfdual regular algebraic cuspidal automorphic representations are
Zariski-dense in a polarized Galois deformation ring. We prove new results in
this direction in the context of automorphic forms on definite unitary groups
over totally real fields. This generalizes the infinite fern argument of
Gouvea-Mazur and Chenevier, and relies on the construction of non-classical
-adic automorphic forms, and the computation of the tangent space of the
space of trianguline Galois representations. This boils down to a surprising
statement about the linear envelope of intersections of Borel subalgebras
What is the Role of Legal Systems in Financial Intermediation? Theory and Evidence
We develop a theory and empirical test of how the legal system affects the relationship between venture capitalists and entrepreneurs. The theory uses a double moral hazard framework to show how optimal contracts and investor actions depend on the quality of the legal system. The empirical evidence is based on a sample of European venture capital deals. The main results are that with better legal protection, investors give more non-contractible support and demand more downside protection. These predictions are supported by the empirical analysis. Using a new empirical approach of comparing two sets of fixed-effect regressions, we also find that the investor’s legal system is more important than that of the company in determining investor behavior.Financial Intermediation;Law and Finance;Corporate Governance;Venture Capital
The Importance of Trust for Investment: Evidence From Venture Capital (Revision of DP 2009-43)
We examine the effect of trust on financial investment and contracting decisions in a micro-economic environment where trust is exogenous. Using hand-collected data on European venture capital, we show that the Eurobarometer measure of trust among nations significantly affects investment decisions. This holds even after controlling for investor and company fixed effects, geographic distance, information and transaction costs. The national identity of venture capital firms’ individual partners further contributes to the effect of trust. Education and work experience reduce the effect of trust but do not eliminate it. We also examine the relationship between trust and sophisticated contracts involving contingent control rights and find that, even after controlling for endogeneity, they are complements, not substitutes.Venture Capital;Social Capital;Trust;Financial Contracts;Corporate Governance.
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