New developments in the quantization of supersymmetric solitons (kinks, vortices and monopoles)

We discuss the one-loop quantum corrections to the mass M and central charge Z of supersymmetric solitons: the kink, the vortex and the monopole. Contrary to previous expectations and published results, in each of these cases there are nonvanishing quantum corrections to the mass. For the N=1 kink and the N=2 monopole a new anomaly in Z rescues BPS saturation (M=Z); for the N=2 vortex, BPS saturation is rescued for two reasons: (i) the quantum fluctuations of the Higgs field acquire a nontrivial phase due to the winding of the classical solution, and (ii) a fermionic zero mode used in the literature is shown not to be normalizable.Comment: 15 pages, REVTEX4 style, 1 embedded postscript figure. Extended writeup of a talk given by P. van Nieuwenhuizen at the XXIV Brazilian National Meeting on Particles and Fields (Caxambu, Brazil, 30 Sep - 4 Oct 2003); to appear in the Brazilian Journal of Physic

Native defects in the Co2_2TiZZ (Z=Z= Si, Ge, Sn) full Heusler alloys: formation and influence on the thermoelectric properties

We have performed first-principles investigations on the native defects in the full Heusler alloys Co$_2$Ti$Z$ ($Z$ one of the group IV elements Si, Ge, Sn), determining their formation energies and how they influence the transport properties. We find that Co vacancies (Vc) in all compounds and the Ti$_\text{Sn}$ anti-site exhibit negative formation energies. The smallest positive values occur for Co in excess on anti-sites (Co$_Z$ or Co$_\text{Ti}$) and for Ti$_Z$. The most abundant native defects were modeled as dilute alloys, treated with the coherent potential approximation in combination with the multiple-scattering theory Green function approach. The self-consistent potentials determined this way were used to calculate the residual resistivity via the Kubo-Greenwood formula and, based on its energy dependence, the Seebeck coefficient of the systems. The latter is shown to depend significantly on the type of defect, leading to variations that are related to subtle, spin-orbit coupling induced, changes in the electronic structure above the half-metallic gap. Two of the systems, Vc$_\text{Co}$ and Co$_Z$, are found to exhibit a negative Seebeck coefficient. This observation, together with their low formation energy, offers an explanation for the experimentally observed negative Seebeck coefficient of the Co$_2$Ti$Z$ compounds as being due to unintentionally created native defects

Quantum corrections to mass and central charge of supersymmetric solitons

We review some recent developments in the subject of quantum corrections to soliton mass and central charge. We consider in particular approaches which use local densities for these corrections, as first discussed by Hidenaga Yamagishi. We then consider dimensional regularization of the supersymmetric kink in 1+1 dimensions and an extension of this method to a 2+1-dimensional gauge theory with supersymmetric abelian Higgs vortices as the solitons.Comment: 41 pages. Contribution to the Hidenaga Yamagishi commemorative volume of Physics Reports, edited by E. Witten and I. Zahe

Edit propagation using geometric relationship functions

We propose a method for propagating edit operations in 2D vector graphics, based on geometric relationship functions. These functions quantify the geometric relationship of a point to a polygon, such as the distance to the boundary or the direction to the closest corner vertex. The level sets of the relationship functions describe points with the same relationship to a polygon. For a given query point, we first determine a set of relationships to local features, construct all level sets for these relationships, and accumulate them. The maxima of the resulting distribution are points with similar geometric relationships. We show extensions to handle mirror symmetries, and discuss the use of relationship functions as local coordinate systems. Our method can be applied, for example, to interactive floorplan editing, and it is especially useful for large layouts, where individual edits would be cumbersome. We demonstrate populating 2D layouts with tens to hundreds of objects by propagating relatively few edit operations

Learning shape placements by example

We present a method to learn and propagate shape placements in 2D polygonal scenes from a few examples provided by a user. The placement of a shape is modeled as an oriented bounding box. Simple geometric relationships between this bounding box and nearby scene polygons define a feature set for the placement. The feature sets of all example placements are then used to learn a probabilistic model over all possible placements and scenes. With this model, we can generate a new set of placements with similar geometric relationships in any given scene. We introduce extensions that enable propagation and generation of shapes in 3D scenes, as well as the application of a learned modeling session to large scenes without additional user interaction. These concepts allow us to generate complex scenes with thousands of objects with relatively little user interaction

Evaluating the efficacy, safety and evolution of renal function with early initiation of everolimus-facilitated tacrolimus reduction in de novo liver transplant recipients: Study protocol for a randomized controlled trial

Background: Introduction of calcineurin inhibitors had led to improved survival rates in liver transplant recipients. However, long-term use of calcineurin inhibitors is associated with a higher risk of chronic renal failure, neurotoxicity, de novo malignancies, recurrence of hepatitis C viral (HCV) infection and hepatocellular carcinoma. Several studies have shown that everolimus has the potential to provide protection against viral replication, malignancy, and progression of fibrosis, as well as preventing nephrotoxicity by facilitating calcineurin inhibitor reduction without compromising efficacy. The Hephaistos study evaluates the beneficial effects of early initiation of everolimus in de novo liver transplant recipients. Methods/Design: Hephaistos is an ongoing 12-month, multi-center, open-label, controlled study aiming to enroll 330 de novo liver transplant recipients from 15 centers across Germany. Patients are randomized in a 1:1 ratio (7–21 days post-transplantation) to receive everolimus (trough levels 3–8 ng/mL) with reduced tacrolimus (trough levels <5 ng/mL), or standard tacrolimus (trough levels 6–10 ng/mL) after entering a run-in period (3–5 days post-transplantation). In the run-in period, patients are treated with induction therapy, mycophenolate mofetil, tacrolimus, and corticosteroids according to local practice. Randomization is stratified by HCV status and model of end-stage liver disease scores at transplantation. The primary objective of the study is to exhibit superior renal function (estimated glomerular filtration rate assessed by the Modification of Diet in Renal Disease (MDRD)-4 formula) with everolimus plus reduced tacrolimus compared to standard tacrolimus at Month 12. Other objectives are: to assess the incidence of treated biopsy-proven acute rejection, graft loss, or death; the incidences of components of the composite efficacy endpoint; renal function via estimated glomerular filtration rate using various formulae (MDRD-4, Nankivell, Cockcroft-Gault, chronic kidney disease epidemiology collaboration and Hoek formulae); the incidence of proteinuria; the incidence of adverse events and serious adverse events; the incidence and severity of cytomegalovirus and HCV infections and HCV-related fibrosis. Discussion: This study aims to demonstrate superior renal function, comparable efficacy, and safety in de novo liver transplant recipients receiving everolimus with reduced tacrolimus compared with standard tacrolimus. This study also evaluates the antiviral benefit by early initiation of everolimus. Trial registration: NCT0155121

Future Needs for Tribo-Corrosion Research and Testing

Tribo-corrosion is an emerging interdisciplinary subject that spans from basic research on the behavior of surfaces in mechanical contact in chemically active surroundings to the test methods needed to quantify its effects, and from the selection of materials for bio-implants to the minimization of surface degradation and wastage in advanced energy conversion systems. Such a diverse field brings with it many challenges in understanding, testing, standardization, and application to engineering practice. This paper summarizes a panel discussion and participant survey held at the Third International Symposium on Tribo-Corrosion in Atlanta, Georgia, USA, in April 2012. It reflects a sense of agreement on many of the key scientific challenges in the field and the fact that tribo-corrosion is still in its infancy in terms of broad industry recognition, education, and the ability of those who conduct tribo-corrosion research to connect their laboratory results and theories to applications. Some sub-fields, notably the bio-tribo-corrosion of medical implants, have witnessed active international research efforts, but the engineering community in many other important areas of technology may not yet be aware of the field despite numerous tribo-corrosion problems that may exist within their purview

Evaluating eGovernment in the Large - A Requirements Oriented Approach

An increasing level of cooperation between public administrations nowadays on national, regional and local level requires methods to develop interoperable eGovernment systems and leads to the necessity of an efficient evaluation and requirements engineering process. In this paper, we propose a framework to systematically gather and evaluate requirements for eGovernment in the large. The evaluation framework is designed to help requirements engineers to develop a suitable evaluation and requirements engineering process. The methodology is motivated and explained on the basis of a European research project