77 research outputs found
Λ and K production in Pb-Pb and pp collisions with ALICE at the LHC
No full textIn this work, the transverse momentum spectra of Λ and K measured with the ALICE experiment at the LHC are discussed. Measurements are presented for colliding systems of protons, at centre of mass energies 2.76 TeV and 7 TeV, and for lead ions at a centre of mass energy of 2.76 TeV per nucleon.
The spectra are discussed within a theoretical framework of a thermally equilibrated, hydrodynamically evolving system, which serves to explain the shape of the spectra for p 6 GeV/c jet quenching is evident, but no evidence of particle species dependance in jet quenching is observed.
The Λ/K ratio shows an enhancement for 2 < p < 6 GeV/c, peaking at 1.5 for the 5% most central Pb–Pb collisions compared to 0.6 for pp. This is discussed in terms of a coalescence model. It cannot be explained purely by enhanced baryon production, but must also involve a redistribution of particles within p. This supports the hydrodynamical picture of hadron production. A brief comparison to the results presently available in p–Pb collisions at the LHC is also given
<em>D</em> Meson Elliptic Flow in Noncentral Pb-Pb Collisions at √s<sub><em>NN</em></sub>=2.76 TeV
No full textAzimuthally anisotropic distributions of D0, D+, and D*+ mesons were studied in the central rapidity region (|y|<0.8) in Pb-Pb collisions at a center-of-mass energy √sNN=2.76 TeV per nucleon-nucleon collision, with the ALICE detector at the LHC. The second Fourier coefficient v2 (commonly denoted elliptic flow) was measured in the centrality class 30%–50% as a function of the D meson transverse momentum pT, in the range 2–16 GeV/c. The measured v2 of D mesons is comparable in magnitude to that of light-flavor hadrons. It is positive in the range 2<pT<6 GeV/c with 5.7σ significance, based on the combination of statistical and systematic uncertainties.</p
Production of charged pions, kaons and protons at large transverse momenta in pp and Pb–Pb collisions at√s<sub>NN</sub> = 2.76 TeV
No full textTransverse momentum spectra of π±, K± and p(p ̄) up to pT = 20 GeV/c at mid-rapidity in pp, peripheral (60–80%) and central (0–5%) Pb–Pb collisions at √sNN = 2.76 TeV have been measured using the ALICE detector at the Large Hadron Collider. The proton-to-pion and the kaon-to-pion ratios both show a distinct peak at pT ≈ 3 GeV/c in central Pb–Pb collisions. Below the peak, pT < 3 GeV/c, both ratios are in good agreement with hydrodynamical calculations, suggesting that the peak itself is dominantly the result of radial flow rather than anomalous hadronization processes. For pT > 10 GeV/c particle ratios in pp and Pb–Pb collisions are in agreement and the nuclear modification factors for π±, K± and p(p ̄) indicate that, within the systematic and statistical uncertainties, the suppression is the same. This suggests that the chemical composition of leading particles from jets in the medium is similar to that of vacuum jets
Transverse Momentum Distribution and Nuclear Modification Factor of Charged Particles in p-Pb Collisions at √sNN=5.02 TeV
No full textThe transverse momentum (p_T) distribution of primary charged particles is measured in non single-diffractive p-Pb collisions at sqrt{s_NN} = 5.02 TeV with the ALICE detector at the LHC. The p_T spectra measured near central rapidity in the range 0.5 < p_T < 20 GeV/c exhibit a weak pseudorapidity dependence. The nuclear modification factor R_pPb is consistent with unity for p_T above 2 GeV/c. This measurement indicates that the strong suppression of hadron production at high p_T observed in Pb-Pb collisions at the LHC is not due to an initial-state effect. The measurement is compared to theoretical calculations
Abortion, reproductive technology, and euthanasia:: Post-concolliar responses from within the Roman Catholic Church in England and Wales 1965-2000
No full textThis thesis is the product of original research into the responses offered by the Roman Catholic Church in England and Wales to the subjects of abortion, reproductive technology, and euthanasia, during the years 1965 to 2000. While focused on the period following the Second Vatican Council (1962-1965), it also offers an introductory historical overview of the Catholic moral tradition, and, more precisely, it assesses relevant pre-Conciliar responses from within the English and Welsh Catholic Church. The main substance of the thesis concentrates on post-Conciliar treatment of abortion, reproductive technology, and euthanasia, providing detailed and comprehensive exposition of the themes under review, and reflective analysis of their significance. Through an extensive location and examination of primary and secondary sources, this investigation makes an original contribution to the understanding of the bioethical attitude and approach of the Roman Catholic Church in England and Wales. In this, it is necessarily contextualised within a wider appreciation of social, moral, and ecclesiological questions. The thesis, together with its inclusive bibliography, provides a useful point of reference for any further and future research in this area
Pseudorapidity Density of Charged Particles in p+Pb Collisions at √s<sub>NN</sub>=5.02 TeV
No full textThe charged-particle pseudorapidity density measured over four units of pseudorapidity in nonsingle-diffractive p+Pb collisions at a center-of-mass energy per nucleon pair √sNN=5.02 TeV is presented. The average value at midrapidity is measured to be 16.81±0.71 (syst), which corresponds to 2.14±0.17 (syst) per participating nucleon, calculated with the Glauber model. This is 16% lower than in nonsingle-diffractive pp collisions interpolated to the same collision energy and 84% higher than in d+Au collisions at √sNN=0.2 TeV. The measured pseudorapidity density in p+Pb collisions is compared to model predictions and provides new constraints on the description of particle production in high-energy nuclear collisions.</p
Pion, Kaon, and Proton Production in Central Pb-Pb Collisions at √sNN=2.76 TeV
No full textIn this Letter we report the first results on π±, K±, p, and p̅ production at midrapidity (|y|<0.5) in central Pb-Pb collisions at √sNN=2.76 TeV, measured by the ALICE experiment at the LHC. The pT distributions and yields are compared to previous results at √sNN=200 GeV and expectations from hydrodynamic and thermal models. The spectral shapes indicate a strong increase of the radial flow velocity with √sNN, which in hydrodynamic models is expected as a consequence of the increasing particle density. While the K/π ratio is in line with predictions from the thermal model, the p/π ratio is found to be lower by a factor of about 1.5. This deviation from thermal model expectations is still to be understood
The impacts of new neighborhoods on poor families: evaluating the policy implications of the moving to opportunity demonstration
No full textThis paper was presented at the conference "Policies to Promote Affordable Housing," cosponsored by the Federal Reserve Bank of New York and New York University's Furman Center for Real Estate and Urban Policy, February 7, 2002. It was part of Session 3: The Impact of Housing on People and Places.Housing ; Housing policy ; Poverty ; Demography
Intravenous or nebulised magnesium sulphate versus standard therapy for severe acute asthma (3Mg trial): a double-blind, randomised controlled trial
No full textBACKGROUND: Neuraminidase inhibitors were widely used during the 2009-10 influenza A H1N1 pandemic, but evidence for their effectiveness in reducing mortality is uncertain. We did a meta-analysis of individual participant data to investigate the association between use of neuraminidase inhibitors and mortality in patients admitted to hospital with pandemic influenza A H1N1pdm09 virus infection. METHODS: We assembled data for patients (all ages) admitted to hospital worldwide with laboratory confirmed or clinically diagnosed pandemic influenza A H1N1pdm09 virus infection. We identified potential data contributors from an earlier systematic review of reported studies addressing the same research question. In our systematic review, eligible studies were done between March 1, 2009 (Mexico), or April 1, 2009 (rest of the world), until the WHO declaration of the end of the pandemic (Aug 10, 2010); however, we continued to receive data up to March 14, 2011, from ongoing studies. We did a meta-analysis of individual participant data to assess the association between neuraminidase inhibitor treatment and mortality (primary outcome), adjusting for both treatment propensity and potential confounders, using generalised linear mixed modelling. We assessed the association with time to treatment using time-dependent Cox regression shared frailty modelling. FINDINGS: We included data for 29,234 patients from 78 studies of patients admitted to hospital between Jan 2, 2009, and March 14, 2011. Compared with no treatment, neuraminidase inhibitor treatment (irrespective of timing) was associated with a reduction in mortality risk (adjusted odds ratio [OR] 0·81; 95% CI 0·70-0·93; p=0·0024). Compared with later treatment, early treatment (within 2 days of symptom onset) was associated with a reduction in mortality risk (adjusted OR 0·48; 95% CI 0·41-0·56; p<0·0001). Early treatment versus no treatment was also associated with a reduction in mortality (adjusted OR 0·50; 95% CI 0·37-0·67; p<0·0001). These associations with reduced mortality risk were less pronounced and not significant in children. There was an increase in the mortality hazard rate with each day's delay in initiation of treatment up to day 5 as compared with treatment initiated within 2 days of symptom onset (adjusted hazard ratio [HR 1·23] [95% CI 1·18-1·28]; p<0·0001 for the increasing HR with each day's delay). INTERPRETATION: We advocate early instigation of neuraminidase inhibitor treatment in adults admitted to hospital with suspected or proven influenza infection. FUNDING: F Hoffmann-La Roche
- …
