437 research outputs found

    ASY-EOS experiment at GSI: Constraining symmetry energy with neutron and proton elliptic flows

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    The Equation Of State of asymmetric nuclear matter is of fundamental importance for both nuclear physics and astrophysics. However, the present understanding of the EOS is limited, largely due to the poor knowledge of the density dependence of the nuclear symmetry energy. In fact, while considerable progress has been made recently in determining the behaviour of symmetry energy at sub-normal nuclear matter density, much more work is still needed to probe its behaviour at high density. The ASY-EOS experiment at GSI will measure elliptic flow (squeeze-out) of neutrons, protons and light complex particles in reactions of isospin asymmetric systems at pre-relativistic energies, in order to provide quantitative information on the density dependence of symmetry energy at densities larger than the saturation one

    Towards a model-independent constraint of the high-density dependence of the symmetry energy

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    Neutron-proton elliptic flow difference and ratio have been shown to be promising observables in the attempt to constrain the density dependence of the symmetry energy above the saturation point from heavy-ion collision data. Their dependence on model parameters like microscopic nucleon-nucleon cross-sections, compressibility of nuclear matter, optical potential, and symmetry energy parametrization is thoroughly studied. By using a parametrization of the symmetry energy derived from the momentum dependent Gogny force in conjunction with the T\"{u}bingen QMD model and comparing with the experimental FOPI/LAND data for 197Au+197Au collisions at 400 MeV/nucleon, a moderately stiff, x=-1.35 +/- 1.25, symmetry energy is extracted, a result that agrees with that of a similar study that employed the UrQMD transport model and a momentum independent power-law parametrization of the symmetry energy. This contrasts with diverging results extracted from the FOPI π−/π+\pi^{-}/\pi^{+} ratio available in the literature.Comment: 18 pages, 3 figures, accepted for publication in Phys. Rev.

    Morphological variation of the newly confirmed population of the javelin sand boa, Eryx jaculus (Linnaeus, 1758) (Serpentes, erycidae) in Sicily, Italy

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    The presence of the Javelin sand boa in Sicily has recently been confirmed. Here the morphological characters and sexual dimorphism of the Sicilian population of Eryx jaculus are presented. Seven meristic and six metric characters in 96 specimens from Sicily were examined. The results show that tail length, snout-vent length, the distance between nostrils and the number of ventral and subcaudal scales are different between sexes. The characters found in the Sicilian population of the Javelin sand boa resemble those of the African population (ssp. jaculus) rather than the Eurasian population (ssp. turcicus), but biomolecular studies are necessary to understand its taxonomic identity

    Flow probe of symmetry energy in relativistic heavy-ion reactions

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    Flow observables in heavy-ion reactions at incident energies up to about 1 GeV per nucleon have been shown to be very useful for investigating the reaction dynamics and for determining the parameters of reaction models based on transport theory. In particular, the elliptic flow in collisions of neutron-rich heavy-ion systems emerges as an observable sensitive to the strength of the symmetry energy at supra-saturation densities. The comparison of ratios or differences of neutron and proton flows or neutron and hydrogen flows with predictions of transport models favors an approximately linear density dependence, consistent with ab-initio nuclear-matter theories. Extensive parameter searches have shown that the model dependence is comparable to the uncertainties of existing experimental data. Comprehensive new flow data of high accuracy, partly also through providing stronger constraints on model parameters, can thus be expected to improve our knowledge of the equation of state of asymmetric nuclear matter.Comment: 20 pages, 24 figures, review to appear in EPJA special volume on nuclear symmetry energ

    Neutrophil CD64 as a marker of infection in patients admitted to the emergency department with acute respiratory failure

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    Introduction: Cluster of differentiation 64 (CD64) is expressed on neutrophils during bacterial infections and sepsis. The aim of our study was to assess the CD64 expression in patients admitted to the emergency department (ED) with a triage diagnosis of acute respiratory failure (ARF) and/or dyspnea and to verify a relationship between its value and the presence of infection. Methods: We assessed neutrophil CD64 expression in peripheral blood of patients admitted to the ED with a diagnosis of ARF and/or dyspnea from September 2012 to April 2013. We mea- sured CD64 index by flow cytometry (Leuko64TM kit) and classified patients as infected within 12 hours from admission, without an infection within 12 hours but infected within 72 hours from admission, and not infected. The primary outcome was differentiating CD64 values of patients with a diagnosis of infection within 12 hours and 72 hours from admission, from those of patients without a diagnosis of infection. The secondary outcome was verifying a relationship between CD64 values and patients’ characteristics, Sequential Organ Failure Assessment score, and intensive care unit admission. Results: Of 212 patients included in the study, 40.1% were classified as infected within 12 hours from admission, 20.3% were without an infection 12 hours after admission but were infected within 72 hours, and 39.6% were not infected. The median CD64 index was higher in patients with an infection on admission (CD64 index: 3.58) than in those not considered infected (CD64 index: 1.37), P,0.0001. Among patients not infected at admission, the CD64 index was higher in those with an infection detected during the following hours of observation (CD64 index: 2.75) than in patients without a diagnosis of infection (CD64 index: 1.28), P,0.0001. A CD64 index .3.65 showed a sensitivity of 94.6%, a specificity of 86.8%, and an area under the receiver-operating characteristic curve of 0.952 for prediction of intensive care unit admission. Conclusion: CD64 index could represent a useful diagnostic tool for differential diagnosis of ARF in the ED

    Canine Mesenchymal Stem Cells from visceral and subcutaneuous adipose tissue for cell-based therapy

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    This study compared some characteristics of canine Adipose tissue-Derived Mesenchymal Stem Cells (cAD-MSCs) from subcutaneous and visceral fat. These findings were directed to obtain high quantity and quality cAD-MSCs for clinical cell-based therapy

    Effect of High-Fidelity Simulation on Medical Students' Knowledge about Advanced Life Support: A Randomized Study

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    High-fidelity simulation (HFS) is a learning method which has proven effective in medical education for technical and non-technical skills. However, its effectiveness for knowledge acquisition is less validated. We performed a randomized study with the primary aim of investigating whether HFS, in association with frontal lessons, would improve knowledge about advanced life support (ALS), in comparison to frontal lessons only among medical students. The secondary aims were to evaluate the effect of HFS on knowledge acquisition of different sections of ALS and personal knowledge perception. Participants answered a pre-test questionnaire consisting of a subjective (evaluating personal perception of knowledge) and an objective section (measuring level of knowledge) containing 100 questions about algorithms, technical skills, team working/early warning scores/communication strategies according to ALS guidelines. All students participated in 3 frontal lessons before being randomized in group S, undergoing a HFS session, and group C, receiving no further interventions. After 10 days from the end of each intervention, both groups answered a questionnaire (post-test) with the same subjective section but a different objective one. The overall number of correct answers of the post-test was significantly higher in group S (mean 74.1, SD 11.2) than in group C (mean 65.5, SD 14.3), p = 0.0017, 95% C.I. 3.34 - 13.9. A significantly higher number of correct answers was reported in group S than in group C for questions investigating knowledge of algorithms (p = 0.0001; 95% C.I 2.22-5.99) and team working/early warning scores/communication strategies (p = 0.0060; 95% C.I 1.13-6.53). Students in group S showed a significantly higher score in the post-test subjective section (p = 0.0074). A lower proportion of students in group S confirmed their perception of knowledge compared to group C (p = 0.0079). HFS showed a beneficial effect on knowledge of ALS among medical students, especially for notions of algorithms and team working/early warning scores/communication
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