50,812 research outputs found
Mix-and-match compatibility in asymmetric system markets
This paper shows that the private incentive for mix-and-match compatibility in system markets diverges from the social planner's incentive if competing suppliers are asymmetric in production cost or product quality. There can be too much or too little compatibility when the market is served by fully integrated system suppliers. Also, the market outcome involves socially too much incompatibility in the form of exclusive technological alliances when the market is composed of independent component suppliers. These results contrast with the standard one obtained in the symmetric setup and shed new light on public policy towards compatibility, technological alliances, and bundling practices in system markets
Site-directed mutagenesis of the proposed catalytic amino acids of the Sindbis virus capsid protein autoprotease
The structural proteins of Sindbis virus are translated as a polyprotein precursor that is cleaved upon translation. The capsid protein is postulated to be a serine protease that releases itself from the N terminus of the nascent polyprotein by autoproteolysis. We have tested the importance in autoproteolysis of His-141, Asp-147, and Ser-215, previously postulated to form the catalytic triad of the protease, and of Asp-163. Several site-specific mutations were constructed at each of these positions, and the release of the capsid protein during translation in a cell-free system was examined. Because proteolysis occurs in cis during translation, the kinetics of release cannot be determined in this system, but the extent of proteolysis can be ascertained. Ser-215 appears to be the catalytic serine of the proteinase. Cys or Thr could substitute inefficiently for Ser-215, but substitution with Ala or Ile led to complete loss of activity. His-141 was also important for proteolysis. Substitution with Ala or Pro led to total loss of activity. Surprisingly, substitution with Arg resulted in complete proteolysis in vitro. Changes at the two Asp residues resulted in complete proteolysis of the substrate in vitro. All mutations that resulted in at least partial cleavage in vitro were incorporated into a full-length clone of Sindbis virus and an attempt was made to recover mutant virus. All changes tested were lethal for the virus except Asp-163 to Asn. Thus, production of infectious virus is either a more sensitive measure of the catalytic rate than the extent of in vitro cleavage, or these residues have necessary functions in addition to their possible role in proteolysis
A Bayesian partial identification approach to inferring the prevalence of accounting misconduct
This paper describes the use of flexible Bayesian regression models for
estimating a partially identified probability function. Our approach permits
efficient sensitivity analysis concerning the posterior impact of priors on the
partially identified component of the regression model. The new methodology is
illustrated on an important problem where only partially observed data is
available - inferring the prevalence of accounting misconduct among publicly
traded U.S. businesses
Interplay between Hbs and bsgamma in the MSSM with Non-Minimal Flavour Violation
We investigate the constraints on flavour-changing neutral heavy Higgs-boson
decays H-> b \bar s from b -> s gamma bounds on the flavour-mixing parameters
of the MSSM with non-minimal flavour violation (NMFV). In our analysis we
include the contributions from the SM and new physics due to general flavour
mixing in the squark mass matrices. We study the case of one and two non-zero
flavour-mixing parameters and find that in the latter case the interference can
raise the Higgs flavour-changing branching ratios by one or two orders of
magnitude with respect to previous predictions based on a single non-zero
parameter and in agreement with present constraints from physics. In the
course of our work we developed a new "FeynArts" model file for the NMFV MSSM
and added the necessary code for the evaluation to "FormCalc". Both extensions
are publicly available.Comment: LaTeX2e, 15 pages, 4 figures. Computation improved and figures
replaced accordingly. Some references added. Main conclusions remain
untouche
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