626 research outputs found
Genome wide association mapping of grain arsenic, copper, molybdenum and zinc in rice (Oryza sativa L.) grown at four international field sites
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The convective storm initiation project
Copyright @ 2007 AMSThe Convective Storm Initiation Project (CSIP) is an international project to understand precisely where, when, and how convective clouds form and develop into showers in the mainly maritime environment of southern England. A major aim of CSIP is to compare the results of the very high resolution Met Office weather forecasting model with detailed observations of the early stages of convective clouds and to use the newly gained understanding to improve the predictions of the model. A large array of ground-based instruments plus two instrumented aircraft, from the U.K. National Centre for Atmospheric Science (NCAS) and the German Institute for Meteorology and Climate Research (IMK), Karlsruhe, were deployed in southern England, over an area centered on the meteorological radars at Chilbolton, during the summers of 2004 and 2005. In addition to a variety of ground-based remote-sensing instruments, numerous rawin-sondes were released at one- to two-hourly intervals from six closely spaced sites. The Met Office weather radar network and Meteosat satellite imagery were used to provide context for the observations made by the instruments deployed during CSIP. This article presents an overview of the CSIP field campaign and examples from CSIP of the types of convective initiation phenomena that are typical in the United Kingdom. It shows the way in which certain kinds of observational data are able to reveal these phenomena and gives an explanation of how the analyses of data from the field campaign will be used in the development of an improved very high resolution NWP model for operational use.This work is funded by the National Environment Research Council following an initial award from the HEFCE Joint Infrastructure Fund
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
New insights into the genetic diversity of Schistosoma mansoni and S. haematobiumin Yemen
The file attached is the Published/publisher’s pdf version of the article.© 2015 Sady et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated
Search for R-parity-violating supersymmetry in events with four or more leptons in sqrt(s) =7 TeV pp collisions with the ATLAS detector
A search for new phenomena in final states with four or more leptons (electrons or muons) is presented. The analysis is based on 4.7 fb−1 of proton-proton collisions delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in two signal regions: one that requires moderate values of missing transverse momentum and another that requires large effective mass. The results are interpreted in a simplified model of R-parity-violating supersymmetry in which a 95% CL exclusion region is set for charged wino masses up to 540 GeV. In an R-parity-violating MSUGRA/CMSSM model, values of m 1/2 up to 820 GeV are excluded for 10 < tan β < 40
Cell cycle regulation of astrocytes by extracellular nucleotides and fibroblast growth factor-2
Extracellular ATP enhances the mitogenic activity of fibroblast growth factor-2 (FGF2) in astrocytes, but the molecular mechanism underlying this synergistic interaction is not known. To determine whether the potentiating effect of extracellular ATP involves cell cycle control mechanisms, we have measured the expression of cyclins that are induced in different phases of the cell cycle in primary cultures of rat cortical astrocytes. We found that ATP potentiated the ability of FGF2 to stimulate expression of cyclin D1, a regulator of cell cycle entry, as well as cyclin A, a regulator of DNA replication. Because FGF2 and P2 purinergic receptors are coupled to extracellular signal regulated protein kinase (ERK), a key member of a signaling cascade that regulates proliferation, we also investigated the role of ERK in regulating cyclin expression induced by FGF2 and ATP. We found that the potentiating effect of ATP on cyclin expression was significantly reduced by U0126, an inhibitor of MEK, the upstream activator of ERK. P2 receptor agonist studies revealed that UTP enhanced FGF2-induced cyclin expression and mitogenesis whereas 2-methylthioADP was ineffective. By contrast, 2-3-O-(4-benzoyl)-benzoyl-ATP markedly inhibited FGF2-induced mitogenesis. Consistent with opposing effects of P2Y and P2X receptors on mitogenesis, UTP stimulated a transient activation of ERK whereas BzATP stimulated a more sustained ERK signal. These findings suggest that signaling by P2Y receptors, most likely of the purine/pyrimidine subtype, enhance the ability of FGF2 to stimulate entry into a new cell cycle, as well as DNA replication, by an ERK-dependent mechanism, whereas signaling by P2X receptors, possibly the P2X7 subtype, inhibits FGF2-induced mitogenesis in astrocytes. Interactions between P2Y, P2X and polypeptide growth factor signaling pathways may have important implications for CNS development as well as injury and repair
Is there a common water-activity limit for the three domains of life?
Archaea and Bacteria constitute a majority of life systems on Earth but have long been considered inferior to Eukarya in terms of solute tolerance. Whereas the most halophilic prokaryotes are known for an ability to multiply at saturated NaCl (water activity (a w) 0.755) some xerophilic fungi can germinate, usually at high-sugar concentrations, at values as low as 0.650-0.605 a w. Here, we present evidence that halophilic prokayotes can grow down to water activities of <0.755 for Halanaerobium lacusrosei (0.748), Halobacterium strain 004.1 (0.728), Halobacterium sp. NRC-1 and Halococcus morrhuae (0.717), Haloquadratum walsbyi (0.709), Halococcus salifodinae (0.693), Halobacterium noricense (0.687), Natrinema pallidum (0.681) and haloarchaeal strains GN-2 and GN-5 (0.635 a w). Furthermore, extrapolation of growth curves (prone to giving conservative estimates) indicated theoretical minima down to 0.611 a w for extreme, obligately halophilic Archaea and Bacteria. These were compared with minima for the most solute-tolerant Bacteria in high-sugar (or other non-saline) media (Mycobacterium spp., Tetragenococcus halophilus, Saccharibacter floricola, Staphylococcus aureus and so on) and eukaryotic microbes in saline (Wallemia spp., Basipetospora halophila, Dunaliella spp. and so on) and high-sugar substrates (for example, Xeromyces bisporus, Zygosaccharomyces rouxii, Aspergillus and Eurotium spp.). We also manipulated the balance of chaotropic and kosmotropic stressors for the extreme, xerophilic fungi Aspergillus penicilloides and X. bisporus and, via this approach, their established water-activity limits for mycelial growth (∼0.65) were reduced to 0.640. Furthermore, extrapolations indicated theoretical limits of 0.632 and 0.636 a w for A. penicilloides and X. bisporus, respectively. Collectively, these findings suggest that there is a common water-activity limit that is determined by physicochemical constraints for the three domains of life
Three-dimensional culture of human meniscal cells: Extracellular matrix and proteoglycan production
<p>Abstract</p> <p>Background</p> <p>The meniscus is a complex tissue whose cell biology has only recently begun to be explored. Published models rely upon initial culture in the presence of added growth factors. The aim of this study was to test a three-dimensional (3D) collagen sponge microenvironment (without added growth factors) for its ability to provide a microenvironment supportive for meniscal cell extracellular matrix (ECM) production, and to test the responsiveness of cells cultured in this manner to transforming growth factor-β (TGF-β).</p> <p>Methods</p> <p>Experimental studies were approved prospectively by the authors' Human Subjects Institutional Review Board. Human meniscal cells were isolated from surgical specimens, established in monolayer culture, seeded into a 3D scaffold, and cell morphology and extracellular matrix components (ECM) evaluated either under control condition or with addition of TGF-β. Outcome variables were evaluation of cultured cell morphology, quantitative measurement of total sulfated proteoglycan production, and immunohistochemical study of the ECM components chondroitin sulfate, keratan sulfate, and types I and II collagen.</p> <p>Result and Conclusion</p> <p>Meniscal cells attached well within the 3D microenvironment and expanded with culture time. The 3D microenvironment was permissive for production of chondroitin sulfate, types I and II collagen, and to a lesser degree keratan sulfate. This microenvironment was also permissive for growth factor responsiveness, as indicated by a significant increase in proteoglycan production when cells were exposed to TGF-β (2.48 μg/ml ± 1.00, mean ± S.D., vs control levels of 1.58 ± 0.79, p < 0.0001). Knowledge of how culture microenvironments influence meniscal cell ECM production is important; the collagen sponge culture methodology provides a useful in vitro tool for study of meniscal cell biology.</p
Successful side-viewing endoscopic hemoclipping for Dieulafoy-like lesion at the brim of a periampullary diverticulum
<p>Abstract</p> <p>Background</p> <p>Duodenal Dieulafoy's lesions are rare and only several cases were reported so far. Their characteristic appearance and location make it difficult to be diagnosed in the clinical practice. Massive bleeding often results from these lesions and can impede the accurate early treatment.</p> <p>Case presentation</p> <p>67 years old male patient suffered a fatal bleeding from Dieulafoy-like lesion located at the mouth of the periampullary diverticulum. Inintial endoscopic therapy and radiologic embolization failed to stop the bleeding, while direct observation and hemoclipping by the side viewing endoscopy successfully established correct diagnosis and permanent cure of the lesion.</p> <p>Conclusion</p> <p>Aggressive endoscopic examinations combined with the accurate endoscopic threatment should be adopted when Dieulafoy-like lesion is suspected as a possible cause of the proximal small bowel hemorrahge. Verification of the diagnosis and definitive treatment often needed repeated examination by side-viewing endoscope as well as stabilization of the patient.</p
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