1,600 research outputs found

    Transverse Momentum Spectra in Au+Au and d+Au Collisions at sNN\sqrt{s_{NN}}=200 GeV and the Pseudorapidity Dependence of High pT_T Suppression

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    We present spectra of charged hadrons from Au+Au and d+Au collisions at sNN=200\sqrt{s_{NN}}=200 GeV measured with the BRAHMS experiment at RHIC. The spectra for different collision centralities are compared to spectra from p+pˉ{\rm p}+\bar{{\rm p}} collisions at the same energy scaled by the number of binary collisions. The resulting ratios (nuclear modification factors) for central Au+Au collisions at η=0\eta=0 and η=2.2\eta=2.2 evidence a strong suppression in the high pTp_{T} region (>>2 GeV/c). In contrast, the d+Au nuclear modification factor (at η=0\eta=0) exhibits an enhancement of the high pTp_T yields. These measurements indicate a high energy loss of the high pTp_T particles in the medium created in the central Au+Au collisions. The lack of suppression in d+Au collisions makes it unlikely that initial state effects can explain the suppression in the central Au+Au collisions.Comment: 4 pages, 4 figures, submitted to Phys. Rev. Let

    Rapidity Dependence of Charged Antiparticle-to-Particle Ratios in Au+Au Collisions at sNN=200\sqrt{s_{NN}}=200 GeV

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    We present ratios of the numbers of charged antiparticles to particles (pions, kaons and protons) in Au + Au collisions at sNN=200\sqrt{s_{NN}}=200 GeV as a function of rapidity in the range yy=0-3. While the particle ratios at midrapidity are approaching unity, the K−/K+K^-/K^+ and pˉ/p\bar{p}/p ratios decrease significantly at forward rapidities. An interpretation of the results within the statistical model indicates a reduction of the baryon chemical potential from μB≈130\mu_B \approx 130MeV at yy=3 to μB≈25\mu_B \approx 25MeV at yy=0.Comment: 4 pages, 4 figure

    Corticospinal excitability changes following blood flow restriction training of the tibialis anterior: a preliminary study

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    © 2017 The Authors Aim To examine the neural excitability of projections to the tibialis anterior (TA) following blood flow restriction training (BFRT). This is the first study to examine the TA following BFRT. Methods Ten subjects performed each experiment. Experiment one consisted of BFRT at 130 mmHg (BFRT-low). Experiment two consisted of BFRT at 200 mmHg (BFRT-high), training (TR-only) and blood flow restriction at 200 mmHg (BFR-only) performed on separate days. Blood flow restriction was applied to the thigh and training consisted of rapid dorsiflexion contractions against gravity every 10 s for 15-min. The motor evoked potential (MEP) peak-to-peak amplitudes were recorded pre-intervention and 1-, 10-, 20- and 30-min post-intervention and expressed relative to the maximal peak-to-peak M-wave at each time-point. Results Experiment one revealed no difference in MEP amplitudes for BFRT-low over time (P = 0.09). Experiment two revealed a significant effect of time (P < 0.001), with 1-min post-intervention MEP amplitudes significantly facilitated compared to pre-intervention, but no effect of intervention (P = 0.79) or intervention*time interaction (P = 0.25). Post-hoc power calculations were performed for the intervention*time interaction. Discussion and conclusions Corticospinal excitability of projections to the TA did not change following BFRT-low and corticospinal excitability changes between BFRT-high, BFR-only and TR-only interventions were not different over time. In experiment two, there was a significant main effect of time 1-min post-intervention which was mainly due to the BFRT-high intervention. Post-hoc power calculations revealed that 15 subjects were required for a significant interaction effect 80% of the time however, as the changes in corticospinal excitability were not prolonged, a new dataset of ≥ 15 subjects was not acquired

    Ventilation management and outcomes in out-of-hospital cardiac arrest: a protocol for a preplanned secondary analysis of the TTM2 trial

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    IntroductionMechanical ventilation is a fundamental component in the management of patients post cardiac arrest. However, the ventilator settings and the gas-exchange targets used after cardiac arrest may not be optimal to minimise post-anoxic secondary brain injury. Therefore, questions remain regarding the best ventilator management in such patients.Methods and analysisThis is a preplanned analysis of the international randomised controlled trial, targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (OHCA)–target temperature management 2 (TTM2). The primary objective is to describe ventilatory settings and gas exchange in patients who required invasive mechanical ventilation and included in the TTM2 trial. Secondary objectives include evaluating the association of ventilator settings and gas-exchange values with 6 months mortality and neurological outcome. Adult patients after an OHCA who were included in the TTM2 trial and who received invasive mechanical ventilation will be eligible for this analysis. Data collected in the TTM2 trial that will be analysed include patients’ prehospital characteristics, clinical examination, ventilator settings and arterial blood gases recorded at hospital and intensive care unit (ICU) admission and daily during ICU stay.Ethics and disseminationThe TTM2 study has been approved by the regional ethics committee at Lund University and by all relevant ethics boards in participating countries. No further ethical committee approval is required for this secondary analysis. Data will be disseminated to the scientific community by abstracts and by original articles submitted to peer-reviewed journals.Trial registration numberNCT02908308

    Earthquake fault dynamics: Insights from laboratory experiments

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    The determination of rock friction under the conditions of seismic slip in the Earth crust (slip rates of the order of 1 m/s or more and normal stress of hundreds of MPa) is of paramount importance in earthquake mechanics. Fault friction controls the stress drop, the mechanical work and the frictional heat generated during the slip. However the essential engine of earthquakes is buried at several kilometers depth and only remote, indirect measurements, which are not sufficient to fully characterize fault dynamics, are available. Elucidating constraints are derived from experimental studies performed in powerful apparatuses applying rotary shear motion to rock samples. The experiments indicate that when slip velocities and normal stresses approach those of actual earthquakes, a significant decrease in friction kicks-in (of up to one order of magnitude), which we term fault lubrication, both for cohesive rocks (silicate-built, quartz-built and carbonate-built) and non-cohesive rocks (clay-rich, anhydrite, gypsum and dolomite gouges) typical of crustal seismogenic sources. The available mechanical work and the associated temperature rise in the slipping zone trigger a number of physicochemical processes (gelification, decarbonation and dehydration reactions, melting and so on) whose products are responsible for fault lubrication

    Cost-effectiveness of alternative methods of surgical repair of inguinal hernia

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    Objectives: To assess the relative cost-effectiveness of laparoscopic methods of inguinal hernia repair compared with open flat mesh and open non-mesh repair. Methods: Data on the effectiveness of these alternatives came from three systematic reviews comparing: (i) laparoscopic methods with open flat mesh or non-mesh methods; (ii) open flat mesh with open non-mesh repair; and (iii) methods that used synthetic mesh to repair the hernia defect with those that did not. Data on costs were obtained from the authors of economic evaluations previously conducted alongside trials included in the reviews. A Markov model was used to model cost-effectiveness for a five-year period after the initial operation. The outcomes of the model were presented using a balance sheet approach and as cost per hernia recurrence avoided and cost per extra day at usual activities. Results: Open flat mesh was the most cost-effective method of preventing recurrences. Laparoscopic repair provided a shorter period of convalescence and less long-term pain compared with open flat mesh but was more costly. The mean incremental cost per additional day back at usual activities compared with open flat mesh was €38 and €80 for totally extraperitoneal and transabdominal preperitoneal repair, respectively. Conclusions: Laparoscopic repair is not cost-effective compared with open flat mesh repair in terms of cost per recurrence avoided. Decisions about the use of laparoscopic repair depend on whether the benefits (reduced pain and earlier return to usual activities) outweigh the extra costs and intraoperative risks. On the evidence presented here, these extra costs are unlikely to be offset by the short-term benefits of laparoscopic repair.Luke Vale, Adrian Grant, Kirsty McCormack, Neil W. Scott and the EU Hernia Trialists Collaboratio

    Drug-microbiota interactions and treatment response: Relevance to rheumatoid arthritis

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    Knowledge about associations between changes in the structure and/or function of intestinal microbes (the microbiota) and the pathogenesis of various diseases is expanding. However, interactions between the intestinal microbiota and different pharmaceuticals and the impact of these on responses to treatment are less well studied. Several mechanisms are known by which drug-microbiota interactions can influence drug bioavailability, efficacy, and/or toxicity. This includes direct activation or inactivation of drugs by microbial enzymes which can enhance or reduce drug effectiveness. The extensive metabolic capabilities of the intestinal microbiota make it a hotspot for drug modification. However, drugs can also influence the microbiota profoundly and change the outcome of interactions with the host. Additionally, individual microbiota signatures are unique, leading to substantial variation in host responses to particular drugs. In this review, we describe several known and emerging examples of how drug-microbiota interactions influence the responses of patients to treatment for various diseases, including inflammatory bowel disease, type 2 diabetes and cancer. Focussing on rheumatoid arthritis (RA), a chronic inflammatory disease of the joints which has been linked with microbial dysbiosis, we propose mechanisms by which the intestinal microbiota may affect responses to treatment with methotrexate which are highly variable. Furthering our knowledge of this subject will eventually lead to the adoption of new treatment strategies incorporating microbiota signatures to predict or improve treatment outcomes

    Web based survey to measuring social interactions, values, attitudes and travel behavior

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    This paper presents the data collection methodology developed for Minerva research project. The aim of Minerva is to study the influence of values, attitudes and social interactions on travel behavior. For this purpose, a web based survey has been developed, which consists of several questionnaires to collect respondents’ values and attitudes; a two-day activity-travel diary; information about social interactions; and socio-demographic characteristics.To identify the social contacts, it is being used a contact diary methodology together with the activity-travel diary
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