1,032 research outputs found

    Differential freezeout and pion interferometry at RHIC from covariant transport theory

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    Puzzling discrepancies between recent pion interferometry data on Au+Au reactions at s^1/2 = 130 and 200 AGeV from RHIC and predictions based on ideal hydrodynamics are analyzed in terms of covariant parton transport theory. The discrepancies of out and longitudinal radii are significantly reduced when the finite opacity of the gluon plasma is taken into account.Comment: 4 pages, 3 EPS figures. Submitted to PR

    ON TWO CONJECTURES RELATED TO ADMISSIBLE GROUPS AND QUASIGROUPS

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    Non-equilibrium Higgs transition in classical scalar electrodynamics

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    Real time rearrangement of particle spectra is studied numerically in a U(1) Gauge+Higgs system, in the unitary gauge and in three spatial dimensions. The cold system starts from the symmetric phase. Evolution of the partial energy densities and pressures reveal well-defined equations of state for the longitudinal and transversal gauge fields very early. Longitudinal modes are excited more efficiently and thermalize the slowest. Hausdorff-dimension of the Higgs-defect manifold, eventually seeding vortex excitations is thoroughly discussed. Scaling dependence of the vortex density on the characteristic time of the symmetry breaking transition is established.Comment: 17 pages, 7 figures, Replaced with version accepted for publication in JHE

    Numerical Simulation of Welding Process – Application in Buckling Analysis

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    Systemic inflammatory challenges compromise survival after experimental stroke via augmenting brain inflammation, blood- brain barrier damage and brain oedema independently of infarct size

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    <p>Abstract</p> <p>Background</p> <p>Systemic inflammation impairs outcome in stroke patients and experimental animals via mechanisms which are poorly understood. Circulating inflammatory mediators can activate cerebrovascular endothelium or glial cells in the brain and impact on ischaemic brain injury. One of the most serious early clinical complications of cerebral ischaemia is brain oedema, which compromises survival in the first 24-48 h. It is not understood whether systemic inflammatory challenges impair outcome after stroke by increasing brain injury only or whether they have direct effects on brain oedema, cerebrovascular inflammation and blood-brain barrier damage.</p> <p>Methods</p> <p>We used two different systemic inflammatory stimuli, acute endotoxin treatment and anaphylaxis to study mechanisms of brain injury after middle cerebral artery occlusion (MCAo). Ischaemic brain injury, blood-brain barrier damage and oedema were analysed by histological techniques. Systemic cytokine responses and inflammatory changes in the brain were analysed by cytometric bead array, immunofluorescence, <it>in situ </it>hibridization and quantitative real-time PCR.</p> <p>Results</p> <p>Systemic inflammatory challenges profoundly impaired survival in the first 24 h after experimental stroke in mice, independently of an increase in infarct size. Systemic lipopolysaccharide (LPS) dose-dependently increased mortality (50-100%) minutes to hours after cerebral ischaemia. Acute anaphylactic challenge in ovalbumin-sensitised mice affected stroke more seriously when induced via intraperitoneal administration compared to intravenous. Both LPS and anaphylaxis induced inflammatory changes in the blood and in the brain prior to experimental stroke. Plasma cytokine levels were significantly higher after LPS, while increased IL-10 levels were seen after anaphylaxis. After MCAo, both LPS and anaphylaxis increased microglial interleukin-1α (IL-1α) expression and blood-brain barrier breakdown. LPS caused marked granulocyte recruitment throughout the ipsilateral hemisphere. To investigate whether reduction of ischaemic damage can improve outcome in systemic inflammation, controlled hypothermia was performed. Hypothermia reduced infarct size in all treatment groups and moderately improved survival, but failed to reduce excess oedema formation after anaphylaxis and LPS-induced neuroinflammation.</p> <p>Conclusions</p> <p>Our results suggest that systemic inflammatory conditions induce cerebrovascular inflammation via diverse mechanisms. Increased brain inflammation, blood-brain barrier injury and brain oedema formation can be major contributors to impaired outcome in mice after experimental stroke with systemic inflammatory stimuli, independently of infarct size.</p

    Application of electronic tongue to discriminate white wines originated from different regions of Hungary

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    In this work, the application of an electronic tongue (ET) based on a specific ion-selective sensor array for discrimination of different white wine types is presented. The electronic tongue equipped with specific sensor array containing seven IFSET sensors was used to analyze wine samples. The obtained ET responses were evaluated using different pattern recognition methods. Principal component analysis (PCA) provides the possibility to identify some initial patterns. Linear discriminant analysis (LDA) was used to build models to separate white wine samples based on wine regions and grape cultivars. The results showed that every group was distinguished from each other with no misclassification error. Furthermore, the sequence of the wine sample groups was similar to the increasing total acidity content. Partial least square (PLS) regression was used to build models for the prediction of the main chemical compositions of the wine samples based on the electronic tongue results. The closest correlation (R2=0.93) was found in case of ‘total acidity’, and the prediction error (RMSEP) was 6.9%. The pH of the wine samples was predicted with good correlation (R2=0.89) but higher prediction error (RMSEP=10.71%) from the electronic tongue results. The ET combining these statistical methods can be applied to determine the origin and variety of the wine samples in easy and quick way

    Functional diversity: a review of methodology and current knowledge in freshwater macroinvertebrate research

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    Although several studies have examined the functional diversity of freshwater macroinvertebrates, the variety of methodologies combined with the absence of a synthetic review make our understanding of this field incomplete. Therefore, we reviewed the current methodology for assessing functional diversity in freshwater macroinvertebrate research. Our review showed that most papers quantified functional diversity using biological traits, among which feeding habits were the most common traits probably due to the assumed links between feeding and ecosystem functions. A large number of diversity measures have been applied for quantifying functional diversity of freshwater macroinvertebrate assemblages, among which Rao’s quadratic entropy looks like the most frequent. In most papers, functional diversity was positively related to taxon richness, and functional redundancy was a key concept in explaining this correlation. Most studies detected strong influence of the environmental factors as well as human impact on functional diversity. Finally, our review revealed that functional diversity research is biased towards European running waters and is hindered by yet insufficient information on the autecology of macroinvertebrates. © 2016 The Author(s
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