4,096 research outputs found

    Near-infrared identification of the counterpart to X1908+075: a new OB-supergiant X-ray binary

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    We report the near-infrared (IR) identification of the likely counterpart to X1908+075, a highly-absorbed Galactic X-ray source recently suspected to belong to the rare class of OB supergiant-neutron star binary systems. Our JHKs-band imaging of the field reveals the existence within the X-ray error boxes of a near-IR source consistent with an early-type star lying at d=7 kpc and suffering A(V)=16 mag of extinction, the latter value being in good agreement with the hydrogen column density derived from a modelling of the X-ray spectrum. Our follow-up, near-IR spectroscopic observations confirm the nature of this candidate and lead to a late O-type supergiant classification, thereby supporting the identification of a new Galactic OB-supergiant X-ray binary.Comment: Accepted for publication in MNRAS, 7 pages, 3 figure

    How Cultural Perceptions and Food Preparation Affect Westerners View of Insects as Food

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    There has been a recent push to encourage westerners to introduce insects into their diets. Traditional arguments that stress environmental and nutritional benefits have been largely unsuccessful. This not because people simply find insects distasteful; what people view as an acceptable food choice is culturally dependent, and foods made from novel and unfamiliar ingredients or tools are met with apprehension. What is less known is why insects are viewed as an unacceptable food source in western society. It has been suggested that westerners disgust towards insects is that insects are perceived of as contaminants and as vectors of disease. If westerners are unwilling to eat insects, or food prepared with insects because they are viewed as unhygienic, then we should expect individuals who are less concerned with hygiene to be more willing to eat insects, or food prepared with insects. When surveyed on their hygiene and their willingness to try food prepared using insects, participants that were less concerned with personal hygiene were more willing to eat food made with insects. In order to convince people to introduce insects into their diet one must know why people are so uneager to consume insects

    Population I Wolf-Rayet Runaway Stars: the Case of WR124 and its Expanding Nebula M1-67

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    In 1997 and 2008 we used the WFPC2 camera on board of the Hubble Space Telescope to obtain two sets of narrow-band Hα\alpha images of the runaway Wolf-Rayet (WR) star WR 124 surrounded by its nebula M1-67. This two-epoch imaging provides an expansion parallax and thus a practically assumption-free geometric distance to the nebula, d=3.35 +/- 0.67 kpc. Combined with the global velocity distribution in the ejected nebula, this confirms the extreme runaway status of WR 124. WR stars embedded within such ejection nebulae, at the point of core-collapse would produce different supernova characteristics from those expected for stars surrounded by wind-filled cavities. In galaxies with extremely low ambient metallicity, Z <= 10^{-3} Z_Sun, gamma-ray bursts originating from fast-moving runaway WR stars may produce afterglows which appear to be coming from regions with a relatively homogeneous circumburst medium.Comment: 13 pages, 2 figures; accepted by ApJ

    An Investigation of the Large-scale Variability of the Apparently Single Wolf-Rayet Star WR 1

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    In recent years, much studies have focused on determining the origin of the large-scale line-profile and/or photometric patterns of variability displayed by some apparently single Wolf-Rayet stars, with the existence of an unseen (collapsed?) companion or of spatially extended wind structures as potential candidates. We present observations of WR 1 which highlight the unusual character of the variations in this object. Our narrowband photometric observations reveal a gradual increase of the stellar continuum flux amounting to Delta v = 0.09 mag followed by a decline on about the same timescale (3-4 days). Only marginal evidence for variability is found during the 11 following nights. Strong, daily line-profile variations are also observed but they cannot be easily linked to the photometric variations. Similarly to the continuum flux variations, coherent time-dependent changes are observed in 1996 in the centroid, equivalent width, and skewness of He II 4686. Despite the generally coherent nature of the variations, we do not find evidence in our data for the periods claimed in previous studies. While the issue of a cyclical pattern of variability in WR 1 is still controversial, it is clear that this object might constitute in the future a cornerstone for our understanding of the mechanisms leading to the formation of largely anisotropic outflows in Wolf-Rayet stars.Comment: 11 pages, 9 figures, accepted for publication in Astronomy & Astrophysic

    SwissDock, a protein-small molecule docking web service based on EADock DSS

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    Most life science processes involve, at the atomic scale, recognition between two molecules. The prediction of such interactions at the molecular level, by so-called docking software, is a non-trivial task. Docking programs have a wide range of applications ranging from protein engineering to drug design. This article presents SwissDock, a web server dedicated to the docking of small molecules on target proteins. It is based on the EADock DSS engine, combined with setup scripts for curating common problems and for preparing both the target protein and the ligand input files. An efficient Ajax/HTML interface was designed and implemented so that scientists can easily submit dockings and retrieve the predicted complexes. For automated docking tasks, a programmatic SOAP interface has been set up and template programs can be downloaded in Perl, Python and PHP. The web site also provides an access to a database of manually curated complexes, based on the Ligand Protein Database. A wiki and a forum are available to the community to promote interactions between users. The SwissDock web site is available online at http://www.swissdock.ch. We believe it constitutes a step toward generalizing the use of docking tools beyond the traditional molecular modeling communit

    Automated Code Generation for Lattice Quantum Chromodynamics and beyond

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    We present here our ongoing work on a Domain Specific Language which aims to simplify Monte-Carlo simulations and measurements in the domain of Lattice Quantum Chromodynamics. The tool-chain, called Qiral, is used to produce high-performance OpenMP C code from LaTeX sources. We discuss conceptual issues and details of implementation and optimization. The comparison of the performance of the generated code to the well-established simulation software is also made

    On the processing of dense hetero-nanostructured metallic materials for improved strength / ductility balance by ecae and sps methods

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    This paper has examined some recent findings concerning the processing of fully dense hetero-nanostructured materials (i.e. consisting of nano, ultrafine and micrometric grains) which can be produced by using the interplay between heavy deformation and recrystallization. By plastic deformation of bulk materials, an improved strength/ductility balance can be obtained directly by imparting high strain deformation (by ECAE) until the occurrence of recrystallization. Using a powder metallurgy route, the strong potential of electric field assisted sintering (ECAS) techniques for producing multi-scale microstructures when a milled powder is used is demonstrated. In this case, in addition to modifying the classic processing parameters (time/temperature of SPS), altering the nature of the milled powder - by Y2O3 addition during the milling stage - is also a good way to delay the onset of recrystallization and, thereby, increase the fraction of ultrafine grains

    SwissDock, a protein-small molecule docking web service based on EADock DSS

    Get PDF
    Most life science processes involve, at the atomic scale, recognition between two molecules. The prediction of such interactions at the molecular level, by so-called docking software, is a non-trivial task. Docking programs have a wide range of applications ranging from protein engineering to drug design. This article presents SwissDock, a web server dedicated to the docking of small molecules on target proteins. It is based on the EADock DSS engine, combined with setup scripts for curating common problems and for preparing both the target protein and the ligand input files. An efficient Ajax/HTML interface was designed and implemented so that scientists can easily submit dockings and retrieve the predicted complexes. For automated docking tasks, a programmatic SOAP interface has been set up and template programs can be downloaded in Perl, Python and PHP. The web site also provides an access to a database of manually curated complexes, based on the Ligand Protein Database. A wiki and a forum are available to the community to promote interactions between users. The SwissDock web site is available online at http://www.swissdock.ch. We believe it constitutes a step toward generalizing the use of docking tools beyond the traditional molecular modeling community
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