Conformal Killing spinors and special geometric structures in Lorentzian geometry - a survey

This paper is a survey on special geometric structures that admit conformal Killing spinors based on lectures, given at the ``Workshop on Special Geometric Structures in String Theory'', Bonn, September 2001 and at ESI, Wien, November 2001. We discuss the case of Lorentzian signature and explain which geometries occur up to dimension 6.Comment: Latex2.09, 13 page

Lorentzian twistor spinors and CR-geometry

We prove that there exist global solutions of the twistor equation on the Fefferman spaces of strictly pseudoconvex spin manifolds of arbitrary dimension and we study their properties.Comment: Latex2.09, 32 page

Parallel spinors and holonomy groups on pseudo-Riemannian spinmanifolds

We describe the possible holonomy groups of simply connected irreducible non-locally symmetric pseudo-Riemannian spin manifolds which admit parallel spinors.Comment: Latex2.09, 18 page

Doubly Extended Lie Groups - Curvature, Holonomy and Parallel Spinors

(This is a revised version of the paper) - In the present paper we study the geometry of doubly extended Lie groups with their natural biinvariant metric. We describe the curvature, the holonomy and the space of parallel spinors. This is completely done for all simply connected groups with biinvariantmetric of Lorentzian signature $(1,n-1)$, of signature $(2,n-2)$ and of signature $(p,q)$, where $p+q\leq 6$. Furthermore, some special series with higher signature are discussed.Comment: Latex2e, 30 page

Codazzi spinors and globally hyperbolic manifolds with special holonomy

In this paper we examine the structure of Riemannian manifolds with a special kind of Codazzi tensors. We use them to construct globally hyperbolic Lorentzian manifolds with complete Cauchy hypersurfaces for any weakly irreducible holonomy representation with parallel spinors, i.e. with a holonomy group which is a semidirect product between $\R^{n-2}$ and one of \1, SU(k), Sp(1), G_2 and $Spin(7)$.Comment: 29 pages. to appear in: Mathematische Zeitschrif

Issues to Consider in Converting to Digital Mammography

This paper will outline the reasons that many radiology practices are converting to digital mammography. In addition, we will provide basic information on the issues that must be considered in making the transformation. These include technical matters regarding image display, storage and retrieval, as well as clinical and ergonomic considerations

Assessing the Standalone Sensitivity of Computer-aided Detection (CADe) with Cancer Cases from the Digital Mammographic Imaging Screening Trial (DMIST)

To assess the sensitivities and false detection rates of two CADe systems when applied to digital or screen-film mammograms in detecting the known breast cancer cases from the DMIST breast cancer screening population

Highly significant antiviral activity of HIV-1 LTR-specific tre-recombinase in humanized mice

Stable integration of HIV proviral DNA into host cell chromosomes, a hallmark and essential feature of the retroviral life cycle, establishes the infection permanently. Current antiretroviral combination drug therapy cannot cure HIV infection. However, expressing an engineered HIV-1 long terminal repeat (LTR) site-specific recombinase (Tre), shown to excise integrated proviral DNA in vitro, may provide a novel and highly promising antiviral strategy. We report here the conditional expression of Tre-recombinase from an advanced lentiviral self-inactivation (SIN) vector in HIV-infected cells. We demonstrate faithful transgene expression, resulting in accurate provirus excision in the absence of cytopathic effects. Moreover, pronounced Tre-mediated antiviral effects are demonstrated in vivo, particularly in humanized Rag2−/−γc−/− mice engrafted with either Tre-transduced primary CD4+ T cells, or Tre-transduced CD34+ hematopoietic stem and progenitor cells (HSC). Taken together, our data support the use of Tre-recombinase in novel therapy strategies aiming to provide a cure for HIV