Note on Strange Quarks in the Nucleon

Scalar matrix elements involving strange quarks are studied in several models. Apart from a critical reexamination of results obtained in the Nambu and Jona-Lasinio model we study a scenario, motivated by instanton physics, where spontaneous chiral symmetry breaking is induced by the flavor-mixing 't Hooft interaction only. We also investigate possible contributions of virtual kaon loops to the strangeness content of the nucleon.Comment: 12 pages, latex style. One figure, available from the author upon request. University of Regensburg TPR-94-0

Genome-Wide Analysis of Interchromosomal Interaction Probabilities Reveals Chained Translocations and Overrepresentation of Translocation Breakpoints in Genes in a Cutaneous T-Cell Lymphoma Cell Line

In classical models of tumorigenesis, the accumulation of tumor promoting chromosomal aberrations is described as a gradual process. Next-generation sequencing-based methods have recently revealed complex patterns of chromosomal aberrations, which are beyond explanation by these classical models of karyotypic evolution of tumor genomes. Thus, the term chromothripsis has been introduced to describe a phenomenon, where temporarily and spatially confined genomic instability results in dramatic chromosomal rearrangements limited to segments of one or a few chromosomes. Simultaneously arising and misrepaired DNA double-strand breaks are also the cause of another phenomenon called chromoplexy, which is characterized by the presence of chained translocations and interlinking deletion bridges involving several chromosomes. In this study, we demonstrate the genome-wide identification of chromosomal translocations based on the analysis of translocation-associated changes in spatial proximities of chromosome territories on the example of the cutaneous T-cell lymphoma cell line Se-Ax. We have used alterations of intra- and interchromosomal interaction probabilities as detected by genome-wide chromosome conformation capture (Hi-C) to infer the presence of translocations and to fine-map their breakpoints. The outcome of this analysis was subsequently compared to datasets on DNA copy number alterations and gene expression. The presence of chained translocations within the Se-Ax genome, partly connected by intervening deletion bridges, indicates a role of chromoplexy in the etiology of this cutaneous T-cell lymphoma. Notably, translocation breakpoints were significantly overrepresented in genes, which highlight gene-associated biological processes like transcription or other gene characteristics as a possible cause of the observed complex rearrangements. Given the relevance of chromosomal aberrations for basic and translational research, genome-wide high-resolution analysis of structural chromosomal aberrations will gain increasing importance

Polariton propagation in weak confinement quantum wells

Exciton-polariton propagation in a quantum well, under centre-of-mass quantization, is computed by a variational self-consistent microscopic theory. The Wannier exciton envelope functions basis set is given by the simple analytical model of ref. [1], based on pure states of the centre-of-mass wave vector, free from fitting parameters and "ad hoc" (the so called additional boundary conditions-ABCs) assumptions. In the present paper, the former analytical model is implemented in order to reproduce the centre-of-mass quantization in a large range of quantum well thicknesses (5a_B < L < inf.). The role of the dynamical transition layer at the well/barrier interfaces is discussed at variance of the classical Pekar's dead-layer and ABCs. The Wannier exciton eigenstates are computed, and compared with various theoretical models with different degrees of accuracy. Exciton-polariton transmission spectra in large quantum wells (L>> a_B) are computed and compared with experimental results of Schneider et al.\cite{Schneider} in high quality GaAs samples. The sound agreement between theory and experiment allows to unambiguously assign the exciton-polariton dips of the transmission spectrum to the pure states of the Wannier exciton center-of-mass quantization.Comment: 15 pages, 15 figures; will appear in Phys.Rev.

Whole Earth Telescope observations of the pulsating subdwarf B star PG 0014+067

PG 0014+067 is one of the most promising pulsating subdwarf B stars for seismic analysis, as it has a rich pulsation spectrum. The richness of its pulsations, however, poses a fundamental challenge to understanding the pulsations of these stars, as the mode density is too complex to be explained only with radial and nonradial low degree (l < 3) p-modes without rotational splittings. One proposed solution, for the case of PG 0014+067 in particular, assigns some modes with high degree (l=3). On the other hand, theoretical models of sdB stars suggest that they may retain rapidly rotating cores, and so the high mode density may result from the presence of a few rotationally-split triplet (l=1), quintuplet (l=2) modes, along with radial (l=0) p-modes. To examine alternative theoretical models for these stars, we need better frequency resolution and denser longitude coverage. Therefore, we observed this star with the Whole Earth Telescope for two weeks in October 2004. In this paper we report the results of Whole Earth Telescope observations of the pulsating subdwarf B star PG 0014+067. We find that the frequencies seen in PG 0014+067 do not appear to fit any theoretical model currently available; however, we find a simple empirical relation that is able to match all of the well-determined frequencies in this star.Comment: 19 pages, preprint of paper accepted for publication in The Astrophysical Journa

Towards ensemble asteroseismology of the young open clusters Chi Persei and NGC 6910

As a result of the variability survey in Chi Persei and NGC6910, the number of Beta Cep stars that are members of these two open clusters is increased to twenty stars, nine in NGC6910 and eleven in Chi Persei. We compare pulsational properties, in particular the frequency spectra, of Beta Cep stars in both clusters and explain the differences in terms of the global parameters of the clusters. We also indicate that the more complicated pattern of the variability among B type stars in Chi Persei is very likely caused by higher rotational velocities of stars in this cluster. We conclude that the sample of pulsating stars in the two open clusters constitutes a very good starting point for the ensemble asteroseismology of Beta Cep-type stars and maybe also for other B-type pulsators.Comment: 4 pages, Astronomische Nachrichten, HELAS IV Conference, Arecife, Lanzarote, Feb 2010, submitte

Hyperon Polarization in the Constituent Quark Model

We consider mechanism for hyperon polarization in inclusive production. The main role belongs to the orbital angular momentum and polarization of the strange quark-antiquark pairs in the internal structure of the constituent quarks. We consider a nucleon as a core consisting of the constituent quarks embedded into quark condensate. The nonperturbative hadron structure is based on the results of chiral quark models.Comment: 14 pages, LaTeX, 2 Figures, References adde

Phonons and related properties of extended systems from density-functional perturbation theory

This article reviews the current status of lattice-dynamical calculations in crystals, using density-functional perturbation theory, with emphasis on the plane-wave pseudo-potential method. Several specialized topics are treated, including the implementation for metals, the calculation of the response to macroscopic electric fields and their relevance to long wave-length vibrations in polar materials, the response to strain deformations, and higher-order responses. The success of this methodology is demonstrated with a number of applications existing in the literature.Comment: 52 pages, 14 figures, submitted to Review of Modern Physic

Ornamental plants: annual reports and research reviews

Ohio State University Extension Nursery, Landscape, and Turf Team Directory: 1998 / Jack Kerrigan -- Floriculture Industry Roundtable of Ohio: 1998 / Charles Behnke -- Ohio State University Extension Buckeye Yard and Garden Line / James A. Chatfield, Pamela J. Bennett, Joseph F. Boggs, Gary Y. Gao, Jane C. Martin, David J. Shetlar and Randall H. Zondag -- Environmental and cultural problems of ornamental plants in Ohio: 1997 / Pamela J. Bennett and Jane C. Martin -- Insect and mite activity noted in Ohio nurseries and landscapes: 1997 / Joseph F. Boggs, David J. Shetlar, Jane C. Martin, Pamela J. Bennett, James A. Chatfield, Gary Y. Gao and Chris Carlson -- Summary of ornamental diseases in Ohio: 1997 / James A. Chatfield, Nancy J. Taylor, Stephen N. Nameth, Chris Carlson, Joseph F. Boggs, Jane C. Martin, Dan Balser and David Madison -- Weed problems in Ohio landscapes and nurseries: 1997 / Gary Y. Gao, Joseph F. Boggs, Pamela J. Bennett, Jane C. Martin, Mary Ann Rose, Joseph W. Rimelspach, Randall H. Zondag and William E. Pound -- Wildlife problems in Ohio landscapes: 1997 / Gary Y. Gao, Joseph F. Boggs, Jane C. Martin, Charles T. Behnke and James A. Chatfield -- Summary of turf cultural and disease problems in 1997 / Gary Y. Gao, Joseph F. Boggs, Pamela J. Bennett, Jane C. Martin, Joseph W. Rimelspach and James A. Chatfield -- Master Gardeners serve Ohio / Marianne Riofrio -- The greening of Poland's nurseries / Kenneth D. Cochran and Wojtek Grabczewski -- The marketing potential of Ginkgo biloba in the United States / Kenneth D. Cochran -- Composts in the Landscape: Effects on Soil pH and plant growth / Mary Ann Rose and Hao Wang -- How to optimize disease control using composts / Harry A. J. Hoitink, Wei-Zheng Zhang, David Y. Han, Alexandra G. Stone, Matthew S. Krause and Warren A. Dick -- The flowering sequence of ornamental plants as a tool for predicting the phenology of insect pests / Daniel A. Herms -- Reducing maintenance costs may mean selecting plants with the fewest flaws / T. Davis Sydnor-- Comprehensive aesthetic evaluations of crabapples at Secrest Arboretum in Wooster: 1993-1997 / Erik A. Draper, James A. Chatfield, Kenneth D. Cochran, Peter W. Bristol and David E. Allen -- Precision control of microirrigation for container-grown mini-roses / Robert C. Hansen, Ted H. Short, C. C. Pasian and R. Peter Fynn -- Red thread (Laetisaria fuciformis) control study on perennial ryegrass / Joseph W. Rimelspach, Kerry Kline, Karl Danneberger and Michael Boehm-- Red thread (Laetisaria fuciformis) control study on Kentucky bluegrass / Joseph W. Rimelspach, Kerry Kline, Karl Danneberger and Michael Boehm -- Red thread - from novelty to nuisance / Joseph W. Rimelspach -- Chrysanthemum cultivars differ in response to photoperiod when grown under far-red absorbing filters / M. J. McMahon -- Improving fuchsia cutting performance by grafting / D. M. Napier and M. J. McMahon -- Paint/paclobutrazol mix on the inside surface of rooting wedge cells to control poinsettia cutting height / Claudio C. Pasian -- Response of poinsettias to paclobutrazol in paint applications / Claudio C. Pasian and Daniel K. Struve -- Dynamic transpiration of highly stressed container-grown Acer rubrum / Ted H. Short, Ahmet Irvem and Robert C. Hansen -- Effects of temperature on the development of Asiatic Lilies / J. Steininger and C. C. Pasian-- New publications for 1997-199