6,525 research outputs found

    Slow and fast micro-field components in warm and dense hydrogen plasmas

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    The aim of this work is the investigation of the statistical properties of local electric fields in an ion-electron two component plasmas for coupled conditions. The stochastic fields at a charged or at a neutral point in plasmas involve both slow and fast fluctuation characteristics. The statistical study of these local fields based on a direct time average is done for the first time. For warm and dense plasma conditions, typically Ne≈1018cm−3N_{e}\approx 10^{18}cm^{-3}, % T_{e}\approx 1eV, well controlled molecular dynamics (MD) simulations of neutral hydrogen, protons and electrons have been carried out. Relying on these \textit{ab initio} MD calculations this work focuses on an analysis of the concepts of statistically independent slow and fast local field components, based on the consideration of a time averaged electric field. Large differences are found between the results of these MD simulations and corresponding standard results based on static screened fields. The effects discussed are of importance for physical phenomena connected with stochastic electric field fluctuations, e.g., for spectral line broadening in dense plasmas.Comment: 4 pages, 4 figures, submitted to Phys. Rev. Let

    Coherent imaging of a pure phase object with classical incoherent light

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    By using the ghost imaging technique, we experimentally demonstrate the reconstruction of the diffraction pattern of a {\em pure phase} object by using the classical correlation of incoherent thermal light split on a beam splitter. The results once again underline that entanglement is not a necessary feature of ghost imaging. The light we use is spatially highly incoherent with respect to the object (≈2ÎŒ\approx 2 \mum speckle size) and is produced by a pseudo-thermal source relying on the principle of near-field scattering. We show that in these conditions no information on the phase object can be retrieved by only measuring the light that passed through it, neither in a direct measurement nor in a Hanbury Brown-Twiss (HBT) scheme. In general, we show a remarkable complementarity between ghost imaging and the HBT scheme when dealing with a phase object.Comment: 13 pages, 11 figures. Published in Physical Review A. Replaced version fixes some problems with Figs. 1, 4 and 1

    Searches for axioelectric effect of solar axions with BGO-scintillator and BGO-bolometer detectors

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    A search for axioelectric absorption of 5.5 MeV solar axions produced in the p+d→3He+γ (5.5 MeV)p + d \rightarrow {^3\rm{He}}+\gamma~(5.5~ \rm{MeV}) reaction has been performed with a BGO detectors. A model-independent limit on the product of axion-nucleon gAN3g_{AN}^3 and axion-electron gAeg_{Ae} coupling constants has been obtained: ∣gAe×gAN3∣<1.9×10−10| g_{Ae}\times g_{AN}^3|< 1.9\times 10^{-10} for 90\% C.L..Comment: 5 pages, 3 figures, Proceedings of the 10th Patras Workshop on Axions, WIMPs and WISP 29 June - 4 July 2014, CERN, Geneva, Switzerlan

    Some Open Points in Nonextensive Statistical Mechanics

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    We present and discuss a list of some interesting points that are currently open in nonextensive statistical mechanics. Their analytical, numerical, experimental or observational advancement would naturally be very welcome.Comment: 30 pages including 6 figures. Invited paper to appear in the International Journal of Bifurcation and Chao

    A survey of cost-sensitive decision tree induction algorithms

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    The past decade has seen a significant interest on the problem of inducing decision trees that take account of costs of misclassification and costs of acquiring the features used for decision making. This survey identifies over 50 algorithms including approaches that are direct adaptations of accuracy based methods, use genetic algorithms, use anytime methods and utilize boosting and bagging. The survey brings together these different studies and novel approaches to cost-sensitive decision tree learning, provides a useful taxonomy, a historical timeline of how the field has developed and should provide a useful reference point for future research in this field

    Structure of nanoparticles embedded in micellar polycrystals

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    We investigate by scattering techniques the structure of water-based soft composite materials comprising a crystal made of Pluronic block-copolymer micelles arranged in a face-centered cubic lattice and a small amount (at most 2% by volume) of silica nanoparticles, of size comparable to that of the micelles. The copolymer is thermosensitive: it is hydrophilic and fully dissolved in water at low temperature (T ~ 0{\deg}C), and self-assembles into micelles at room temperature, where the block-copolymer is amphiphilic. We use contrast matching small-angle neuron scattering experiments to probe independently the structure of the nanoparticles and that of the polymer. We find that the nanoparticles do not perturb the crystalline order. In addition, a structure peak is measured for the silica nanoparticles dispersed in the polycrystalline samples. This implies that the samples are spatially heterogeneous and comprise, without macroscopic phase separation, silica-poor and silica-rich regions. We show that the nanoparticle concentration in the silica-rich regions is about tenfold the average concentration. These regions are grain boundaries between crystallites, where nanoparticles concentrate, as shown by static light scattering and by light microscopy imaging of the samples. We show that the temperature rate at which the sample is prepared strongly influence the segregation of the nanoparticles in the grain-boundaries.Comment: accepted for publication in Langmui

    Contemporary data on treatment practices for low-density lipoprotein cholesterol in 3867 patients who had suffered an acute coronary syndrome across the world

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    DYSIS II ACS was a longitudinal, observational study in 3867 patients from 18 countries. They were being hospitalized after suffering an acute coronary syndrome. Evaluations were performed at the time of admission and again 120±15 days following the date of admission (the follow-up time point). 2521 patients were on active lipid lowering treatment (LLT) at admission. Mean atorvastatin dose was 22 mg per day and 2.7% received ezetimibe in combination with a statin. At discharge from hospital, 3767 patients received LLT expressed as a mean atorvastatin dose of 36 mg per day with 4.8% receiving ezetimibe on top of a statin. After 120 days, intensity in lipid lowering treatment was reduced to 32 mg per day with 4.9% of the patients receiving ezetimibe and a statin. Of note, during this 4-month follow up period, only 32% of all patients received laboratory lipid testing. 37% attained the low density lipoprotein cholesterol (LDL-C) target value of <70 mg/dl after 120 days. There are differences in the therapy administered as well as in the switch strategies when comparing the data from the respective countries studied. Conclusions: Only one in three patients achieved the LDL-C target value following only marginal improvements in atorvastatin dose or combination therapy after an ACS event. Keywords: Low-density lipoprotein cholesterol, Treatment target, Global, Region, Statin

    CONUT Score Predicts Early Morbidity After Liver Transplantation: A Collaborative Study

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    Introduction: Liver transplantation (LT) is burdened by the risk of post-operative morbidity. Identifying patients at higher risk of developing complications can help allocate resources in the perioperative phase. Controlling Nutritional Status (CONUT) score, based on lymphocyte count, serum albumin, and cholesterol levels, has been applied to various surgical specialties, proving reliable in predicting complications and prognosis. Our study aims to investigate the role of the CONUT score in predicting the development of early complications (within 90 days) after LT. Methods: This is a retrospective analysis of 209 patients with a calculable CONUT score within 2 months before LT. The ability of the CONUT score to predict severe complications, defined as a Comprehensive Complication Index (CCI) ≄42.1, was examined. Inverse Probability Treatment Weighting was used to balance the study population against potential confounders. Results: Patients with a CCI ≄42.1 had higher CONUT score values (median: 7 vs. 5, P-value &lt; 0.0001). The CONUT score showed a good diagnostic ability regarding post-LT morbidity, with an AUC = 0.72 (95.0%CI = 0.64–0.79; P-value &lt; 0.0001). The CONUT score was the only independent risk factor identified for a complicated post-LT course, with an odds ratio = 1.39 (P-value &lt; 0.0001). The 90-day survival rate was 98.8% and 87.5% for patients with a CONUT score &lt;8 and ≄8, respectively. Conclusions: Pre-operative CONUT score is a helpful tool to identify patients at increased post-LT morbidity risk. Further refinements in the score composition, specific to the LT population, could be obtained with prospective studies

    Role of mitochondrial raft-like microdomains in the regulation of cell apoptosis

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    Lipid rafts are envisaged as lateral assemblies of specific lipids and proteins that dissociate and associate rapidly and form functional clusters in cell membranes. These structural platforms are not confined to the plasma membrane; indeed lipid microdomains are similarly formed at subcellular organelles, which include endoplasmic reticulum, Golgi and mitochondria, named raft-like microdomains. In addition, some components of raft-like microdomains are present within ER-mitochondria associated membranes. This review is focused on the role of mitochondrial raft-like microdomains in the regulation of cell apoptosis, since these microdomains may represent preferential sites where key reactions take place, regulating mitochondria hyperpolarization, fission-associated changes, megapore formation and release of apoptogenic factors. These structural platforms appear to modulate cytoplasmic pathways switching cell fate towards cell survival or death. Main insights on this issue derive from some pathological conditions in which alterations of microdomains structure or function can lead to severe alterations of cell activity and life span. In the light of the role played by raft-like microdomains to integrate apoptotic signals and in regulating mitochondrial dynamics, it is conceivable that these membrane structures may play a role in the mitochondrial alterations observed in some of the most common human neurodegenerative diseases, such as Amyotrophic lateral sclerosis, Huntington's chorea and prion-related diseases. These findings introduce an additional task for identifying new molecular target(s) of pharmacological agents in these pathologies
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