114 research outputs found
On the sensitivity of the HAWC observatory to gamma-ray bursts
We present the sensitivity of HAWC to Gamma Ray Bursts (GRBs). HAWC is a very
high-energy gamma-ray observatory currently under construction in Mexico at an
altitude of 4100 m. It will observe atmospheric air showers via the water
Cherenkov method. HAWC will consist of 300 large water tanks instrumented with
4 photomultipliers each. HAWC has two data acquisition (DAQ) systems. The main
DAQ system reads out coincident signals in the tanks and reconstructs the
direction and energy of individual atmospheric showers. The scaler DAQ counts
the hits in each photomultiplier tube (PMT) in the detector and searches for a
statistical excess over the noise of all PMTs. We show that HAWC has a
realistic opportunity to observe the high-energy power law components of GRBs
that extend at least up to 30 GeV, as it has been observed by Fermi LAT. The
two DAQ systems have an energy threshold that is low enough to observe events
similar to GRB 090510 and GRB 090902b with the characteristics observed by
Fermi LAT. HAWC will provide information about the high-energy spectra of GRBs
which in turn could help to understanding about e-pair attenuation in GRB jets,
extragalactic background light absorption, as well as establishing the highest
energy to which GRBs accelerate particles
ϒ production in p–Pb collisions at √sNN=8.16 TeV
ϒ production in p–Pb interactions is studied at the centre-of-mass energy per nucleon–nucleon collision √sNN = 8.16 TeV with the ALICE detector at the CERN LHC. The measurement is performed reconstructing bottomonium resonances via their dimuon decay channel, in the centre-of-mass rapidity intervals 2.03 < ycms < 3.53 and −4.46 < ycms < −2.96, down to zero transverse momentum. In this work, results on the ϒ(1S) production cross section as a function of rapidity and transverse momentum are presented. The corresponding nuclear modification factor shows a suppression of the ϒ(1S) yields with respect to pp collisions, both at forward and backward rapidity. This suppression is stronger in the low transverse momentum region and shows no significant dependence on the centrality of the interactions. Furthermore, the ϒ(2S) nuclear modification factor is evaluated, suggesting a suppression similar to that of the ϒ(1S). A first measurement of the ϒ(3S) has also been performed. Finally, results are compared with previous ALICE measurements in p–Pb collisions at √sNN = 5.02 TeV and with theoretical calculations.publishedVersio
(Anti-)deuteron production in pp collisions at 1as=13TeV
The study of (anti-)deuteron production in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. In this paper the production of (anti-)deuterons is studied as a function of the charged particle multiplicity in inelastic pp collisions at s=13 TeV using the ALICE experiment. Thanks to the large number of accumulated minimum bias events, it has been possible to measure (anti-)deuteron production in pp collisions up to the same charged particle multiplicity (d Nch/ d \u3b7 3c 26) as measured in p\u2013Pb collisions at similar centre-of-mass energies. Within the uncertainties, the deuteron yield in pp collisions resembles the one in p\u2013Pb interactions, suggesting a common formation mechanism behind the production of light nuclei in hadronic interactions. In this context the measurements are compared with the expectations of coalescence and statistical hadronisation models (SHM)
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
Differential expression of steroid 5 alpha-reductase isozymes and association with disease severity and angiogenic genes predict their biological role in prostate cancer
10.1677/ERC-10-0022Endocrine-Related Cancer173757-770ERCA
Mid-term follow-up of 183 arterial myocardial revascularization procedures
Objecti6e: To evaluate the mid-term results of complete arterial myocardial revascularization performed with arterial conduits.
Methods: From July 1987 to December 1994, 183 patients underwent a myocardial revascularization procedure with the use of at
least two arterial grafts (IMAs, rGEA, IEA) at our institute. Their mean age was 5698.7 years, the redo-operation rate was
16.9% (31:183), two-vessel disease was present in 61 patients (33.3%), three-vessel disease in 122 (66.7%). Results: The LIMA was
used in 179 patients (97.8%), the RIMA in 116 (63.4%), the rGEA in 66 (36.1%) and the IEA in 41 (22.4%). In-hospital mortality
was 1.1% (2:183), while the perioperative myocardial infarction (MI) rate was 2.2% (4:183). The angiographic restudy, performed
on 87 (47.5%) patients during the early postoperative period (median 38 days) showed the following grafts patency rates: LIMA
98.8 (86:87), RIMA 97.1 (34:35), IEA 85.7 (24:28), rGEA 97.05 (33:34) and saphenous vein 90.9% (10:11). The median follow-up
was 35 months. Kaplan-Meier survival was 9692% at 3 and 5 years, freedom from angina 9492% at 3 years and 9193% at
5 years, while the Kaplan-Meier freedom from cardiac events was 9093% at 3 years and 8893% at 5 years. Cox regression
analysis identified perioperative MI (P 0.03, relative risk 3.6) as the only prognostic factor for mortality at follow-up. With
regards to recurrence of angina, multivariate analysis has shown that incremental risk factors for the return of angina are
redo-operation (PB0.01, relative risk 2.7) and the persistence of hypertension after surgery (PB0.01; relative risk 3.2), while the
use of the RIMA in the operation has emerged as a protective factor (P 0.02; relative risk 0.43). Finally, only redo-operation
(PB0.01; relative risk 2.3), has emerged as a predictor of cardiac complications. Conclusion: Myocardial revascularization with
at least two arterial grafts can be performed with very low perioperative morbidity and mortality and good mid-term follow-up.
The mid-term results of arterial myocardial revascularization are less favourable in cases of redo-operations or when the RIMA
is not used
The effect of mirabegron on energy expenditure and brown adipose tissue in healthy lean SouthAsian and Europidmen
Aim To compare the effects of cold exposure and the beta 3-adrenergic receptor agonist mirabegron on plasma lipids, energy expenditure and brown adipose tissue (BAT) activity in South Asians versus Europids. Materials and Methods Ten lean Dutch South Asian (aged 18-30 years; body mass index [BMI] 18-25 kg/m(2)) and 10 age- and BMI-matched Europid men participated in a randomized, double-blinded, cross-over study consisting of three interventions: short-term (similar to 2 hours) cold exposure, mirabegron (200 mg one dose p.o.) and placebo. Before and after each intervention, we performed lipidomic analysis in serum, assessed resting energy expenditure (REE) and skin temperature, and measured BAT fat fraction by magnetic resonance imaging. Results In both ethnicities, cold exposure increased the levels of several serum lipid species, whereas mirabegron only increased free fatty acids. Cold exposure increased lipid oxidation in both ethnicities, while mirabegron increased lipid oxidation in Europids only. Cold exposure and mirabegron enhanced supraclavicular skin temperature in both ethnicities. Cold exposure decreased BAT fat fraction in both ethnicities. After the combination of data from both ethnicities, mirabegron decreased BAT fat fraction compared with placebo. Conclusions In South Asians and Europids, cold exposure and mirabegron induced beneficial metabolic effects. When combining both ethnicities, cold exposure and mirabegron increased REE and lipid oxidation, coinciding with a higher supraclavicular skin temperature and lower BAT fat fraction
Janus2: An FPGA-based supercomputer for spin glass simulations
We describe the past and future of the Janus project. The collaboration started in 2006 and deployed in early 2008 the Janus supercomputer, a facility that allowed to speed-up Monte Carlo Simulations of a class of model glassy systems and provided unprecedented results for some paradigms in Statistical Mechanics. The Janus Supercomputer was based on state-of-the-art FPGA technology, and provided almost two order of magnitude improvement in terms of cost/performance and power/performance ratios. More than four years later, commercial facilities are closing-up in terms of performance, but FPGA technology has largely improved. A new generation supercomputer, Janus2, will be able to improve by more than one orders of magnitude with respect to the previous one, and will accordingly be again the best choice in Monte Carlo simulations of Spin Glasses for several years to come with respect to commercial solutions. © 2012 ACM
An FPGA-based supercomputer for statistical physics: The weird case of Janus
In this chapter we describe the Janus supercomputer, a massively parallel FPGA-based system optimized for the simulation of spin-glasses, theoretical models that describe the behavior of glassy materials. The custom architecture of Janus has been developed to meet the computational requirements of these models. Spin-glass simulations are performed using Monte Carlo methods that lead to algorithms characterized by (1) intrinsic parallelism allowing us to implement many Monte Carlo update engines within a single FPGA; (2) rather small data base (2 MByte) that can be stored on-chip, significantly boosting bandwidth and reducing latency. (3) need to generate a large number of good-quality long (≥ 32 bit) random numbers; (4) mostly integer arithmetic and bitwise logic operations. Careful tailoring of the architecture to the specific features of these algorithms has allowed us to embed up to 1024 special purpose cores within just one FPGA, so that simulations of systems that would take centuries on conventional architectures can be performed in just a few months
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