Gauge unification in noncommutative geometry

Gauge unification is widely considered to be a desirable feature for extensions of the standard model. Unfortunately the standard model itself does not exhibit a unification of its running gauge couplings but it is required by grand unified theories as well as the noncommutative version of the standard model [2]. We will consider here the extension of the noncommutative standard model by vector doublets as proposed in [6]. Two consequences of this modification are: 1. the relations of the coupling constants at unification energy are altered with respect to the well known relation from grand unified theories. 2. The extended model allows for unification of the gauge couplings at ~10^(13) GeV

Cowden syndrome - Diagnostic skin signs

Cowden syndrome is a rare autosomal dominant familial cancer syndrome with a high risk of breast cancer. The most important clinical features include carcinomas of the breast and thyroid, and hamartomatous polyps of the gastrointestinal tract. There are characteristic mucocutaneous features which allow early recognition of the disease and are generally present before internal malignancies develop. We report on a woman in whom the diagnosis of Cowden syndrome was first made after she had been treated for both breast cancer and melanoma. Copyright (C) 2001 S. KargerAG, Basel

FE/BE coupling for an acoustic fluid-structure interaction problem. Residual a posteriori error estimates

This is the author's accepted manuscript. The final published article is available from the link below. Copyright © 2011 John Wiley & Sons, Ltd.In this paper, we developed an a posteriori error analysis of a coupling of finite elements and boundary elements for a fluid–structure interaction problem in two and three dimensions. This problem is governed by the acoustic and the elastodynamic equations in time-harmonic vibration. Our methods combined integral equations for the exterior fluid and FEMs for the elastic structure. It is well-known that because of the reduction of the boundary value problem to boundary integral equations, the solution is not unique in general. However, because of superposition of various potentials, we consider a boundary integral equation that is uniquely solvable and avoids the irregular frequencies of the negative Laplacian operator of the interior domain. In this paper, two stable procedures were considered; one is based on the nonsymmetric formulation and the other is based on a symmetric formulation. For both formulations, we derived reliable residual a posteriori error estimates. From the estimators we computed local error indicators that allowed us to develop an adaptive mesh refinement strategy. For the two-dimensional case we performed an adaptive algorithm on triangles, and for the three-dimensional case we used hanging nodes on hexahedrons. Numerical experiments underline our theoretical results.DFG German Research Foundatio

Are Standards Always Protectionist?

We analyze the effects of a domestic standard that reduces an externality associated with the consumption of the good targeted by the standard, using a model in which foreign and domestic producers compete in the domestic good market. Producers can reduce expected damage associated with the externality by incurring a cost that varies by source of origin. Despite potential protectionism, the standard is useful in correcting the consumption externality in the domestic country. Protectionism occurs when the welfare-maximizing domestic standard is higher than the international standard maximizing welfare inclusive of foreign profits. The standard is actually anti-protectionist when foreign producers are much more efficient at addressing the externality than are domestic producers. Possible exclusion of domestic or foreign producers arises with large standards, which may alter the classification of a standard as protectionist or non-protectionist. The paper provides important implications for the estimation and use of tariff equivalents of nontariff barriers. JEL Classification Code: F13externality; nontariff barriers; protectionism; safety; standard; tariff equivalent