4,402 research outputs found

    Predation of a Bat by American Crows, Corvus brachyrhynchos

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    This report documents predation and possible group hunting of a bat by American Crows (Corvus brachyrhynchos). I observed a group of several crows appear to cooperate in order to ground and catch a bat. Predation of bats by birds in North America is relatively rare, and bat predation by crows has not been previously reported. A cooperative attack would be consistent with other group behaviours of the species, including territoriality, breeding and foraging

    A redshift survey towards the CMB Cold Spot

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    We have carried out a redshift survey using the VIMOS spectrograph on the VLT towards the Cosmic Microwave Background cold spot. A possible cause of the cold spot is the Integrated Sachs-Wolfe effect imprinted by an extremely large void (hundreds of Mpc in linear dimension) at intermediate or low redshifts. The redshift distribution of over seven hundred z<1 emission-line galaxies drawn from an I-band flux limited sample of galaxies in the direction of the cold spot shows no evidence of a gap on scales of Delta-z> 0.05 as would be expected if such a void existed at 0.35<z<1. There are troughs in the redshift distribution on smaller scales (Delta-z ~0.01) indicating that smaller scale voids may connect regions separated by several degrees towards the cold spot. A comparison of this distribution with that generated from similarly-sized subsamples drawn from widely-spaced pointings of the VVDS survey does not indicate that the redshift distribution towards the cold spot is anomalous or that these small gaps can be uniquely attributed to real voids.Comment: MNRAS in press, 6 page

    Final Project Report: Hydraulic Model Study NEORSD Mill Creek Tunnel

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    https://deepblue.lib.umich.edu/bitstream/2027.42/154199/1/39015101405317.pd

    Analysis of longitudinal bunching inan FEL driven two-beam accelerator

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    Recent experiments [1] have explored the use of a free-electron laser (FEL) as a buncher for a microwave two-beam accelerator, and the subsequent driving of a standing-wave rf output cavity. Here we present a deeper analysis of the longitudinal dynamics of the electron bunches as they are transported from the end of the FEL and through the output cavity. In particular, we examine the effect of the transport region and cavity aperture to filter the bunched portion of the beam. [1] T. Lefevre, et. al., Phys. Rev. Lett. 84 (2000), 1188.Comment: 3 pages, 8 figures. Submitted to XX Int'l LINAC Conferenc

    Uterine torsion in the mare: a review and three case reports

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    When a mare exhibits signs of colic during the last trimester of gestation, uterine torsion should always be part of the differential diagnosis. Uterine torsion is an infrequently occurring but serious complication in pregnant mares. In this article a review is given of the appearance, causes, symptoms, diagnostic examinations, treatment options and prognosis for the mare, as well as for her foal. At the end, three unusual cases are described

    Possibilistic Uncertainty Handling for Answer Set Programming

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    In this work, we introduce a new framework able to deal with a reasoning that is at the same time non monotonic and uncertain. In order to take into account a certainty level associated to each piece of knowledge, we use possibility theory to extend the non monotonic semantics of stable models for logic programs with default negation. By means of a possibility distribution we define a clear semantics of such programs by introducing what is a possibilistic stable model. We also propose a syntactic process based on a fix-point operator to compute these particular models representing the deductions of the program and their certainty. Then, we show how this introduction of a certainty level on each rule of a program can be used in order to restore its consistency in case of the program has no model at all. Furthermore, we explain how we can compute possibilistic stable models by using available softwares for Answer Set Programming and we describe the main lines of the system that we have developed to achieve this goal

    EST-PAC HPC - a web portal for high-throughput EST annotation and protein sequence prediction

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    Expressed Sequence Tags (ESTs) are short DNA sequences generated by sequencing the transcribed cDNAs coming from a gene expression. They can provide significant functional, structural and evolutionary information and thus are a primary resource for gene discovery. EST annotation basically refers to the analysis of unknown ESTs that can be performed by database similarity search for possible identities and database search for functional prediction of translation products. Such kind of annotation typically consists of a series of repetitive tasks which should be automated, and be customizable and amenable to using distributed computing resources. Furthermore, processing of EST data should be done efficiently using a high performance computing platform. In this paper, we describe an EST annotator, EST-PACHPC, which has been developed for harnessing HPC resources potentially from Grid and Cloud systems for high throughput EST annotations. The performance analysis of EST-PACHPC has shown that it provides substantial performance gain in EST annotation.<br /
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