13,596 research outputs found
Simulating the impact of dust cooling on the statistical properties of the intracluster medium
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 and the 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 relation
changes only by a maximum of 2% at M whereas the
normalization of the changes by as much as 10% at 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
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
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
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
The Dark Energy Survey Data Management System
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
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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