LAPACK-Based Software for Subspace Identification

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Large-scale structure formation for power spectra with broken scale invariance

We have simulated the formation of large-scale structure arising from COBE-normalized spectra computed by convolving a primordial double-inflation perturbation spectrum with the CDM transfer function. Due to the broken scale invariance ('BSI') characterizing the primordial perturbation spectrum, this model has less small-scale power than the (COBE-normalized) standard CDM model. The particle-mesh code (with $512^3$ cells and $256^3$ particles) includes a model for thermodynamic evolution of baryons in addition to the usual gravitational dynamics of dark matter. It provides an estimate of the local gas temperature. In particular, our galaxy-finding procedure seeks peaks in the distribution of gas that has cooled. It exploits the fact that ``cold" particles trace visible matter better than average and thus provides a natural biasing mechanism. The basic picture of large-scale structure formation in the BSI model is the familiar hierarchical clustering scenario. We obtain particle in cell statistics, the galaxy correlation function, the cluster abundance and the cluster-cluster correlation function and statistics for large and small scale velocity fields. We also report here on a semi-quantitative study of the distribution of gas in different temperature ranges. Based on confrontation with observations and comparison with standard CDM, we conclude that the BSI scenario could represent a promising modification of the CDM picture capable of describing many details of large-scale structure formation.Comment: 15 pages, Latex using mn.sty, uuencoded compressed ps-file with 15 figures by anonymous ftp to ftp://ftp.aip.de/incoming/mueller/bsi.u

Dissipation of Magnetohydrodynamic Waves on Energetic Particles: Impact on Interstellar Turbulence and Cosmic Ray Transport

The physical processes involved in diffusion of Galactic cosmic rays in the interstellar medium are addressed. We study the possibility that the nonlinear MHD cascade sets the power-law spectrum of turbulence which scatters charged energetic particles. We find that the dissipation of waves due to the resonant interaction with cosmic ray particles may terminate the Kraichnan-type cascade below wavelengths 10^13 cm. The effect of this wave dissipation has been incorporated in the GALPROP numerical propagation code in order to asses the impact on measurable astrophysical data. The energy-dependence of the cosmic-ray diffusion coefficient found in the resulting self-consistent model may explain the peaks in the secondary to primary nuclei ratios observed at about 1 GeV/nucleon.Comment: 15 pages, 20 figures, 1 table, emulateapj.cls; To be published in ApJ 10 May 2006, v.64

Chiral Fermions on the Lattice

A recently proposed method for regularizing chiral gauge theories non-perturbatively is discussed in detail. The result is an effective action which can be computed from the lattice gauge field, and which is suited for numerical simulations.Comment: Talk given by G. Schierholz at Yukawa International Seminar on Non-Perturbative QCD: Structure of the QCD Vacuum (YKIS97), Kyoto, December 1997; typos correcte

Discovery of GeV Emission from the Circinus galaxy with the Fermi-LAT

We report the discovery of gamma-ray emission from the Circinus galaxy using the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. Circinus is a nearby (~4 Mpc) starburst with a heavily obscured Seyfert-type active nucleus, bipolar radio lobes perpendicular to the spiral disk, and kpc-scale jet-like structures. Our analysis of 0.1-100 GeV events collected during 4 years of LAT observations reveals a significant (~ 7.3 sigma) excess above the background. We find no indications of variability or spatial extension beyond the LAT point-spread function. A power-law model used to describe the 0.1-100 GeV gamma-ray spectrum yields a flux of (18.8+/-5.8)x10^{-9} ph cm^{-2} s^{-1} and photon index 2.19+/-0.12, corresponding to an isotropic gamma-ray luminosity of 3 x 10^{40} erg s^{-1}. This observed gamma-ray luminosity exceeds the luminosity expected from cosmic-ray interactions in the interstellar medium and inverse Compton radiation from the radio lobes. Thus the origin of the GeV excess requires further investigation.Comment: 7 pages, 7 figures, accepted for publication in the Astrophysical Journa

Salinization dynamics in irrigated soils of the Svetloyarsk irrigation system, Volgograd oblast

On the basis of soil surveys performed by the Volgograd hydrogeological reclamation expedition in 1998 and 2006, published data, and original materials obtained by the authors, the dynamics of soil salinization within the Svetloyarsk irrigation system in Volgograd oblast during the irrigation and post-irrigation periods have been traced. It is found that high irrigation rates under conditions of poor drainage and closed drainage basins upon both shallow (within the Caspian Lowland) and relatively deep (on the Ergeni Upland) occurrence of saline groundwater and the presence of natural salts in the soils and subsoils lead to the rise in the groundwater level above the critical level and the development of secondary salinization in the previously surfacesaline, deeply saline, and even nonsaline soils. During the post-irrigation period (15-18 years) under modern climatic conditions, the groundwater level has been descending to a depth of more than 3 m, and the degree of salinity in the upper meter of light chestnut and meadow-chestnut soils has decreased owing to the leaching of salts with atmospheric precipitation

AD-linked, toxic NH2 human tau affects the quality control of mitochondria in neurons

Functional as well as structural alterations in mitochondria size, shape and distribution are precipitating, early events in progression of Alzheimer's Disease (AD). We reported that a 20\u201322 kDa NH2-tau fragment (aka NH2htau), mapping between 26 and 230 amino acids of the longest human tau isoform, is detected in cellular and animal AD models and is neurotoxic in hippocampal neurons. The NH2htau \u2013but not the physiological full-length protein\u2013 interacts with A\u3b2 at human AD synapses and cooperates with it in inhibiting the mitochondrial ANT-1-dependent ADP/ATP exchange. Here we show that the NH2htau also adversely affects the interplay between the mitochondria dynamics and their selective autophagic clear- ance. Fragmentation and perinuclear mislocalization of mitochondria with smaller size and density are early found in dying NH2htau-expressing neurons. The specific effect of NH2htau on quality control of mitochondria is accompanied by (i) net reduction in their mass in correlation with a general Parkin- mediated remodeling of membrane proteome; (ii) their extensive association with LC3 and LAMP1 autoph- agic markers; (iii) bioenergetic deficits and (iv) in vitro synaptic pathology. These results suggest that NH2htau can compromise the mitochondrial biology thereby contributing to AD synaptic deficits not only by ANT-1 inactivation but also, indirectly, by impairing the quality control mechanism of these organelles

AD-linked, toxic NH2 human tau affects the quality control of mitochondria in neurons

Functional as well as structural alterations in mitochondria size, shape and distribution are precipitating, early events in progression of Alzheimer's Disease (AD). We reported that a 20\u201322 kDa NH2-tau fragment (aka NH2htau), mapping between 26 and 230 amino acids of the longest human tau isoform, is detected in cellular and animal AD models and is neurotoxic in hippocampal neurons. The NH2htau \u2013but not the physiological full-length protein\u2013 interacts with A\u3b2 at human AD synapses and cooperates with it in inhibiting the mitochondrial ANT-1-dependent ADP/ATP exchange. Here we show that the NH2htau also adversely affects the interplay between the mitochondria dynamics and their selective autophagic clear- ance. Fragmentation and perinuclear mislocalization of mitochondria with smaller size and density are early found in dying NH2htau-expressing neurons. The specific effect of NH2htau on quality control of mitochondria is accompanied by (i) net reduction in their mass in correlation with a general Parkin- mediated remodeling of membrane proteome; (ii) their extensive association with LC3 and LAMP1 autoph- agic markers; (iii) bioenergetic deficits and (iv) in vitro synaptic pathology. These results suggest that NH2htau can compromise the mitochondrial biology thereby contributing to AD synaptic deficits not only by ANT-1 inactivation but also, indirectly, by impairing the quality control mechanism of these organelles