A spatial analysis of multivariate output from regional climate models

Climate models have become an important tool in the study of climate and climate change, and ensemble experiments consisting of multiple climate-model runs are used in studying and quantifying the uncertainty in climate-model output. However, there are often only a limited number of model runs available for a particular experiment, and one of the statistical challenges is to characterize the distribution of the model output. To that end, we have developed a multivariate hierarchical approach, at the heart of which is a new representation of a multivariate Markov random field. This approach allows for flexible modeling of the multivariate spatial dependencies, including the cross-dependencies between variables. We demonstrate this statistical model on an ensemble arising from a regional-climate-model experiment over the western United States, and we focus on the projected change in seasonal temperature and precipitation over the next 50 years.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS369 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Complete N-Point Superstring Disk Amplitude II. Amplitude and Hypergeometric Function Structure

Using the pure spinor formalism in part I [1] we compute the complete tree-level amplitude of N massless open strings and find a striking simple and compact form in terms of minimal building blocks: the full N-point amplitude is expressed by a sum over (N-3)! Yang-Mills partial subamplitudes each multiplying a multiple Gaussian hypergeometric function. While the former capture the space-time kinematics of the amplitude the latter encode the string effects. This result disguises a lot of structure linking aspects of gauge amplitudes as color and kinematics with properties of generalized Euler integrals. In this part II the structure of the multiple hypergeometric functions is analyzed in detail: their relations to monodromy equations, their minimal basis structure, and methods to determine their poles and transcendentality properties are proposed. Finally, a Groebner basis analysis provides independent sets of rational functions in the Euler integrals.Comment: 68 pages, harvmac Te

Rat models of autoimmune uveitis

Experimental autoimmune uveitis ( EAU) in Lewis rats is a well-established model for human uveitis. During the last years we used this model to demonstrate extraocular induction of uveitis by antigenic mimicry of environmental antigens with retinal autoantigen and investigated the migration and intraocular reactivation of autoreactive green fluorescent protein ( GFP)+ T cells. We could also elaborate several differences between EAU induced with S-antigen peptide PDSAg or R14, a peptide derived from interphotoreceptor retinoid-binding protein, suggesting two differently regulated diseases in the same rat strain. R14-mediated EAU in Lewis rats has been shown to relapse, thus we have a new model to test therapeutic approaches in an ongoing immune response instead of just preventing disease. Finally, we show antigenic mimicry of PDSAg and an HLA-B peptide for oral tolerance induction. After the successful first therapeutic trial this approach will now proceed with international multicenter clinical trials. Copyright (c) 2008 S. Karger AG, Basel

Modeling Partially Reliable Information Sources: A General Approach Based on Dempster-Shafer Theory

Combining testimonial reports from independent and partially reliable information sources is an important problem of uncertain reasoning. Within the framework of Dempster-Shafer theory, we propose a general model of partially reliable sources which includes several previously known results as special cases. The paper reproduces these results, gives a number of new insights, and thereby contributes to a better understanding of this important application of reasoning with uncertain and incomplete information.Articl

Scaling tests with dynamical overlap and rooted staggered fermions

We present a scaling analysis in the 1-flavor Schwinger model with the full overlap and the rooted staggered determinant. In the latter case the chiral and continuum limit of the scalar condensate do not commute, while for overlap fermions they do. For the topological susceptibility a universal continuum limit is suggested, as is for the partition function and the Leutwyler-Smilga sum rule. In the heavy-quark force no difference is visible even at finite coupling. Finally, a direct comparison between the complete overlap and the rooted staggered determinant yields evidence that their ratio is constant up to $O(a^2)$ effects.Comment: 28 pages, 20 figures containg 37 graphs. v2: 6 new references, 2 new footnotes (to match published version

Spatial isomorphisms of algebras of truncated Toeplitz operators

We examine when two maximal abelian algebras in the truncated Toeplitz operators are spatially isomorphic. This builds upon recent work of N. Sedlock, who obtained a complete description of the maximal algebras of truncated Toeplitz operators.Comment: 24 page