1,250 research outputs found
High-resolution modelling of interactions between soil moisture and convective development in a mountain enclosed Tibetan Basin
Abstract. The Tibetan Plateau plays a significant role in atmospheric circulation and the Asian monsoon system. Turbulent surface fluxes and the evolution of boundary-layer clouds to deep and moist convection provide a feedback system that modifies the plateau's surface energy balance on scales that are currently unresolved in mesoscale models. This work analyses the land surface's role and specifically the influence of soil moisture on the triggering of convection at a cross section of the Nam Co Lake basin, 150 km north of Lhasa using a cloud-resolving atmospheric model with a fully coupled surface. The modelled turbulent fluxes and development of convection compare reasonably well with the observed weather. The simulations span Bowen ratios of 0.5 to 2.5. It is found that convective development is the strongest at intermediate soil moisture. Dry cases with soils close to the permanent wilting point are moisture limited in convective development, while convection in wet soil moisture cases is limited by cloud cover reducing incoming solar radiation and sensible heat fluxes, which has a strong impact on the surface energy balance. This study also shows that local development of convection is an important mechanism for the upward transport of water vapour, which originates from the lake basin that can then be transported to dryer regions of the plateau. Both processes demonstrate the importance of soil moisture and surfaceâatmosphere interactions on the energy and hydrological cycles of the Tibetan Plateau.
This research was funded by the German Research Foundation (DFG) Priority Programme 1372 âTibetan Plateau: Formation, Climate, Ecosystemsâ as part of the AtmosphereâEcologyâGlaciologyâCluster (TiP-AEG): FO 226/18- 1,2. The work described in this publication has been supported by the European Commission (Call FP7-ENV-2007-1 grant no. 212921) as part of the CEOP-AEGIS project coordinated by the University of Strasbourg. The map of Nam Co was produced by Sophie Biskop (University of Jena) and Jan Kropacek (University of TĂŒbingen) within DFG-TiP and Phil Stickler of the Cambridge Geography Department Cartography Unit. This publication was funded by the German Research Foundation (DFG) and the University of Bayreuth in the funding programme Open-Access Publishing.This is the final version of the article. It first appeared from European Geosciences Union via http://dx.doi.org/10.5194/hess-19-4023-201
Inverse spin-s portrait and representation of qudit states by single probability vectors
Using the tomographic probability representation of qudit states and the
inverse spin-portrait method, we suggest a bijective map of the qudit density
operator onto a single probability distribution. Within the framework of the
approach proposed, any quantum spin-j state is associated with the
(2j+1)(4j+1)-dimensional probability vector whose components are labeled by
spin projections and points on the sphere. Such a vector has a clear physical
meaning and can be relatively easily measured. Quantum states form a convex
subset of the 2j(4j+3) simplex, with the boundary being illustrated for qubits
(j=1/2) and qutrits (j=1). A relation to the (2j+1)^2- and
(2j+1)(2j+2)-dimensional probability vectors is established in terms of spin-s
portraits. We also address an auxiliary problem of the optimum reconstruction
of qudit states, where the optimality implies a minimum relative error of the
density matrix due to the errors in measured probabilities.Comment: 23 pages, 4 figures, PDF LaTeX, submitted to the Journal of Russian
Laser Researc
Lack of Cardiac Nerve Sprouting after Intramyocardial Transplantation of Bone Marrow-Derived Stem Cells in a Swine Model of Chronic Ischemic Myocardium
Previous experimental studies suggested that mesenchymal stem cell transplantation causes cardiac nerve sprouting; however, whether bone marrow (BM)-derived mononuclear cells (MNC) and endothelial progenitor cells (EPC) can also lead to cardiac nerve sprouting and alter gap junction expression remains unclear. We investigated the effect of electroanatomical mapping-guided direct intramyocardial transplantation of BM-MNC (nâ=â8) and CD31+EPC (nâ=â8) compared with saline control (nâ=â8) on cardiac nerve sprouting and gap junction expression in a swine model of chronic ischemic myocardium. At 12Â weeks after transplantation, the distribution and density of cardiac nerve sprouting were determined by staining of tyrosine hydroxylase (TH) and growth associated protein 43(GAP-43) and expression of connexin 43 in the targeted ischemic and remote normal myocardium. After 12Â weeks, no animal developed sudden death after the transplantation. There were no significant differences in the number of cells with positive staining of TH and GAP-43 in the ischemic and normal myocardium between three groups. Furthermore, expression of connexin 43 was also similar in the ischemic and normal myocardia in each group of animals (Pâ>â0.05). The results of this study demonstrated that intramyocardial BM-derived MNC or EPC transplantation in a large animal model of chronic myocardial ischemia was not associated with increased cardiac nerve sprouting over the ischemic myocardium
Family history of colorectal cancer in Iran
BACKGROUND: Previous reports show a high proportion of young CRC patients in Iran. In this study we aim to look for the clustering of colorectal cancer in families of a series of CRC patients from Iran. METHODS: The family history of cancer is traced in 449 CRC patients of which 112 were 45 yrs or younger and 337 were older than 45 yrs at time of diagnosis. The patients were admitted in two hospitals in Tehran, during a 4-year period. RESULTS: Clinical diagnosis of HNPCC was established in 21 (4.7%) probands. Family history of CRC was more frequently reported by early-onset than by late-onset patients (29.5% vs. 12.8%, p < 0.001). Distribution of tumor site differed significantly between those with and without family history of CRC. Right colon cancer was the most frequent site (23/45, 35.4%) observed in patients with positive family history of colorectal cancer. CONCLUSION: The relatively high frequency of CRC clustering along with HNPCC in our patients should be further confirmed with larger sample size population-based and genetic studies to establish a cost effective molecular screening for the future
Random-phase approximation and its applications in computational chemistry and materials science
The random-phase approximation (RPA) as an approach for computing the
electronic correlation energy is reviewed. After a brief account of its basic
concept and historical development, the paper is devoted to the theoretical
formulations of RPA, and its applications to realistic systems. With several
illustrating applications, we discuss the implications of RPA for computational
chemistry and materials science. The computational cost of RPA is also
addressed which is critical for its widespread use in future applications. In
addition, current correction schemes going beyond RPA and directions of further
development will be discussed.Comment: 25 pages, 11 figures, published online in J. Mater. Sci. (2012
Conidiation Color Mutants of Aspergillus fumigatus Are Highly Pathogenic to the Heterologous Insect Host Galleria mellonella
The greater wax moth Galleria mellonella has been widely used as
a heterologous host for a number of fungal pathogens including Candida
albicans and Cryptococcus neoformans. A positive
correlation in pathogenicity of these yeasts in this insect model and animal
models has been observed. However, very few studies have evaluated the
possibility of applying this heterologous insect model to investigate virulence
traits of the filamentous fungal pathogen Aspergillus
fumigatus, the leading cause of invasive aspergillosis. Here, we have
examined the impact of mutations in genes involved in melanin biosynthesis on
the pathogenicity of A. fumigatus in the G.
mellonella model. Melanization in A. fumigatus confers
bluish-grey color to conidia and is a known virulence factor in mammal models.
Surprisingly, conidial color mutants in B5233 background that have deletions in
the defined six-gene cluster required for DHN-melanin biosynthesis caused
enhanced insect mortality compared to the parent strain. To further examine and
confirm the relationship between melanization defects and enhanced virulence in
the wax moth model, we performed random insertional mutagenesis in the Af293
genetic background to isolate mutants producing altered conidia colors. Strains
producing conidia of previously identified colors and of novel colors were
isolated. Interestingly, these color mutants displayed a higher level of
pathogenicity in the insect model compared to the wild type. Although some of
the more virulent color mutants showed increased resistance to hydrogen
peroxide, overall phenotypic characterizations including secondary metabolite
production, metalloproteinase activity, and germination rate did not reveal a
general mechanism accountable for the enhanced virulence of these color mutants
observed in the insect model. Our observations indicate instead, that
exacerbated immune response of the wax moth induced by increased exposure of
PAMPs (pathogen-associated molecular patterns) may cause self-damage that
results in increased mortality of larvae infected with the color mutants. The
current study underscores the limitations of using this insect model for
inferring the pathogenic potential of A. fumigatus strains in
mammals, but also points to the importance of understanding the innate immunity
of the insect host in providing insights into the pathogenicity level of
different fungal strains in this model. Additionally, our observations that
melanization defective color mutants demonstrate increased virulence in the
insect wax moth, suggest the potential of using melanization defective mutants
of native insect fungal pathogens in the biological control of insect
populations
MoVam7, a Conserved SNARE Involved in Vacuole Assembly, Is Required for Growth, Endocytosis, ROS Accumulation, and Pathogenesis of Magnaporthe oryzae
Soluble NSF attachment protein receptor (SNARE) proteins play a central role in membrane fusion and vesicle transport of eukaryotic organisms including fungi. We previously identified MoSce22 as a homolog of Saccharomyces cerevisiae SNARE protein Sec22 to be involved in growth, stress resistance, and pathogenicity of Magnaporthe oryzae. Here, we provide evidences that MoVam7, an ortholog of S. cerevisiae SNARE protein Vam7, exerts conserved functions in vacuolar morphogenesis and functions in pathogenicity of M. oryzae. Staining with neutral red and FM4-64 revealed the presence of abnormal fragmented vacuoles and an absence of the Spitzenkörper body in the ÎMovam7 mutant. The ÎMovam7 mutant also exhibited reduced vegetative growth, poor conidiation, and failure to produce the infection structure appressorium. Additionally, treatments with cell wall perturbing agents indicated weakened cell walls and altered distributions of the cell wall component chitin. Furthermore, the ÎMovam7 mutant showed a reduced accumulation of reactive oxygen species (ROS) in the hyphal apex and failed to cause diseases on the rice plant. In summary, our studies indicate that MoVam7, like MoSec22, is a component of the SNARE complex whose functions in vacuole assembly also underlies the growth, conidiation, appressorium formation, and pathogenicity of M. oryzae. Further studies of MoVam7, MoSec22, and additional members of the SNARE complex are likely to reveal critical mechanisms in vacuole formation and membrane trafficking that is linked to fungal pathogenicity
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of âs = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pTâ„20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60â€pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2â€{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration
Observation of associated near-side and away-side long-range correlations in âsNN=5.02ââTeV proton-lead collisions with the ATLAS detector
Two-particle correlations in relative azimuthal angle (ÎÏ) and pseudorapidity (Îη) are measured in âsNN=5.02ââTeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1ââÎŒb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Îη|<5) ânear-sideâ (ÎÏâŒ0) correlation that grows rapidly with increasing ÎŁETPb. A long-range âaway-sideâ (ÎÏâŒÏ) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Îη and ÎÏ) and ÎŁETPb dependence. The resultant ÎÏ correlation is approximately symmetric about Ï/2, and is consistent with a dominant cosâĄ2ÎÏ modulation for all ÎŁETPb ranges and particle pT
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at â s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fbâ1 of â s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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