13,596 research outputs found

    Simulating the impact of dust cooling on the statistical properties of the intracluster medium

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    From the first stages of star and galaxy formation, non-gravitational processes such as ram pressure stripping, SNs, galactic winds, AGNs, galaxy-galaxy mergers, etc... lead to the enrichment of the IGM in stars, metals as well as dust, via the ejection of galactic material into the IGM. We know now that these processes shape, side by side with gravitation, the formation and the evolution of structures. We present here hydrodynamic simulations of structure formation implementing the effect of the cooling by dust on large scale structure formation. We focus on the scale of galaxy clusters and study the statistical properties of clusters. Here we present our results on the TXMT_X-M and the LXML_X-M scaling relations which exhibit changes on both the slope and normalization when adding cooling by dust to the standard radiative cooling model. For example, the normalization of the TXMT_X-M relation changes only by a maximum of 2% at M=1014M=10^{14} M_\odot whereas the normalization of the LXTXL_X-T_X changes by as much as 10% at TX=1T_X=1 keV for models that including dust cooling. Our study shows that the dust is an added non-gravitational process that contributes shaping the thermodynamical state of the hot ICM gas.Comment: 11 pages, 4 figures, ASR in pres

    Genetic analysis of members of the species Oropouche virus and identification of a novel M segment sequence

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    Oropouche virus (OROV) is a public health threat in South America, and in particular Northern Brazil, causing frequent outbreaks of febrile illness. Using a combination of deep sequencing and Sanger sequencing approaches we have determined complete genome sequences of eight clinical isolates that were obtained from patient sera during an Oropouche fever outbreak in Amapa state, northern Brazil in 2009. We also report complete genome sequences of two OROV reassortants isolated from two marmosets in Minas Gerais state, southeast Brazil in 2012 that contain a novel M genome segment. Interestingly, all ten isolates posses a 947 nucleotide long S segment that lacks 11 residues in the S segment 3' UTR compared to the recently redetermined Brazilian prototype OROV strain BeAn19991. OROV maybe circulating more widely in Brazil and in the non-human primate population than previously appreciated and the identification of yet another reassortant highlights the importance of bunyavirus surveillance in South America

    Reducing the power consumption in LTE-advanced wireless access networks by a capacity based deployment tool

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    As both the bit rate required by applications on mobile devices and the number of those mobile devices are steadily growing, wireless access networks need to be expanded. As wireless networks also consume a lot of energy, it is important to develop energy-efficient wireless access networks in the near future. In this study, a capacity-based deployment tool for the design of energy-efficient wireless access networks is proposed. Capacity-based means that the network responds to the instantaneous bit rate requirements of the users active in the selected area. To the best of our knowledge, such a deployment tool for energy-efficient wireless access networks has never been presented before. This deployment tool is applied to a realistic case in Ghent, Belgium, to investigate three main functionalities incorporated in LTE-Advanced: carrier aggregation, heterogeneous deployments, and Multiple-Input Multiple-Output (MIMO). The results show that it is recommended to introduce femtocell base stations, supporting both MIMO and carrier aggregation, into the network (heterogeneous deployment) to reduce the network's power consumption. For the selected area and the assumptions made, this results in a power consumption reduction up to 70%. Introducing femtocell base stations without MIMO and carrier aggregation can already result in a significant power consumption reduction of 38%

    Alterations of the mitochondrial proteome caused by the absence of mitochondrial DNA: A proteomic view

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    The proper functioning of mitochondria requires that both the mitochondrial and the nuclear genome are functional. To investigate the importance of the mitochondrial genome, which encodes only 13 subunits of the respiratory complexes, the mitochondrial rRNAs and a few tRNAs, we performed a comparative study on the 143B cell line and on its Rho-0 counterpart, i.e., devoid of mitochondrial DNA. Quantitative differences were found, of course in the respiratory complexes subunits, but also in the mitochondrial translation apparatus, mainly mitochondrial ribosomal proteins, and in the ion and protein import system, i.e., including membrane proteins. Various mitochondrial metabolic processes were also altered, especially electron transfer proteins and some dehydrogenases, but quite often on a few proteins for each pathway. This study also showed variations in some hypothetical or poorly characterized proteins, suggesting a mitochondrial localization for these proteins. Examples include a stomatin-like protein and a protein sharing homologies with bacterial proteins implicated in tyrosine catabolism. Proteins involved in apoptosis control are also found modulated in Rho-0 mitochondria.Comment: website publisher: http://www3.interscience.wiley.com

    Introdução

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    Número especial do Sociedade Brasileira de Economia Ecológica (ECOECO

    The Dark Energy Survey Data Management System

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    The Dark Energy Survey collaboration will study cosmic acceleration with a 5000 deg2 griZY survey in the southern sky over 525 nights from 2011-2016. The DES data management (DESDM) system will be used to process and archive these data and the resulting science ready data products. The DESDM system consists of an integrated archive, a processing framework, an ensemble of astronomy codes and a data access framework. We are developing the DESDM system for operation in the high performance computing (HPC) environments at NCSA and Fermilab. Operating the DESDM system in an HPC environment offers both speed and flexibility. We will employ it for our regular nightly processing needs, and for more compute-intensive tasks such as large scale image coaddition campaigns, extraction of weak lensing shear from the full survey dataset, and massive seasonal reprocessing of the DES data. Data products will be available to the Collaboration and later to the public through a virtual-observatory compatible web portal. Our approach leverages investments in publicly available HPC systems, greatly reducing hardware and maintenance costs to the project, which must deploy and maintain only the storage, database platforms and orchestration and web portal nodes that are specific to DESDM. In Fall 2007, we tested the current DESDM system on both simulated and real survey data. We used Teragrid to process 10 simulated DES nights (3TB of raw data), ingesting and calibrating approximately 250 million objects into the DES Archive database. We also used DESDM to process and calibrate over 50 nights of survey data acquired with the Mosaic2 camera. Comparison to truth tables in the case of the simulated data and internal crosschecks in the case of the real data indicate that astrometric and photometric data quality is excellent.Comment: To be published in the proceedings of the SPIE conference on Astronomical Instrumentation (held in Marseille in June 2008). This preprint is made available with the permission of SPIE. Further information together with preprint containing full quality images is available at http://desweb.cosmology.uiuc.edu/wik

    Reforma agraria na Amazônia: Balanço e perspectivas

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    En Amazonie, il n'y a pas eu de véritable "réforme agraire". Il y a eu une politique volontariste d'occupation qui a déclenché un processus massif de colonisation et qui a entraîné de graves conséquences environnementales et sociales. Il en est résulté un abandon massif des périmètres agraires et une reconcentration foncière. Alors que le gouvernement du président Cardoso a maintenu ses objectifs d'installation de nouvelles familles, principalement en Amazonie, le taux élevé d'abandon a mis en évidence un manque patent de durabilité économique et environnementale. Le nouveau gouvernement Lula propose une "réforme agraire de qualité". Bien qu'il existe une véritable volonté du gouvernement, les moyens et les conditions politiques seront-ils au rendez-vous? (Résumé d'auteur
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