316 research outputs found

    Healthy lifestyle and life expectancy free of cancer, cardiovascular disease, and type 2 diabetes: prospective cohort study

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    OBJECTIVE: To examine how a healthy lifestyle is related to life expectancy that is free from major chronic diseases. DESIGN: Prospective cohort study. SETTING AND PARTICIPANTS: The Nurses' Health Study (1980-2014; n=73 196) and the Health Professionals Follow-Up Study (1986-2014; n=38 366). MAIN EXPOSURES: Five low risk lifestyle factors: never smoking, body mass index 18.5-24.9, moderate to vigorous physical activity (≥30 minutes/day), moderate alcohol intake (women: 5-15 g/day; men 5-30 g/day), and a higher diet quality score (upper 40%). MAIN OUTCOME: Life expectancy free of diabetes, cardiovascular diseases, and cancer. RESULTS: The life expectancy free of diabetes, cardiovascular diseases, and cancer at age 50 was 23.7 years (95% confidence interval 22.6 to 24.7) for women who adopted no low risk lifestyle factors, in contrast to 34.4 years (33.1 to 35.5) for women who adopted four or five low risk factors. At age 50, the life expectancy free of any of these chronic diseases was 23.5 (22.3 to 24.7) years among men who adopted no low risk lifestyle factors and 31.1 (29.5 to 32.5) years in men who adopted four or five low risk lifestyle factors. For current male smokers who smoked heavily (≥15 cigarettes/day) or obese men and women (body mass index ≥30), their disease-free life expectancies accounted for the lowest proportion (≤75%) of total life expectancy at age 50. CONCLUSION: Adherence to a healthy lifestyle at mid-life is associated with a longer life expectancy free of major chronic diseases

    Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC Collisions

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    We review the most important experimental results from the first three years of nucleus-nucleus collision studies at RHIC, with emphasis on results from the STAR experiment, and we assess their interpretation and comparison to theory. The theory-experiment comparison suggests that central Au+Au collisions at RHIC produce dense, rapidly thermalizing matter characterized by: (1) initial energy densities above the critical values predicted by lattice QCD for establishment of a Quark-Gluon Plasma (QGP); (2) nearly ideal fluid flow, marked by constituent interactions of very short mean free path, established most probably at a stage preceding hadron formation; and (3) opacity to jets. Many of the observations are consistent with models incorporating QGP formation in the early collision stages, and have not found ready explanation in a hadronic framework. However, the measurements themselves do not yet establish unequivocal evidence for a transition to this new form of matter. The theoretical treatment of the collision evolution, despite impressive successes, invokes a suite of distinct models, degrees of freedom and assumptions of as yet unknown quantitative consequence. We pose a set of important open questions, and suggest additional measurements, at least some of which should be addressed in order to establish a compelling basis to conclude definitively that thermalized, deconfined quark-gluon matter has been produced at RHIC.Comment: 101 pages, 37 figures; revised version to Nucl. Phys.

    Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

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    We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC

    Phi meson production in Au+Au and p+p collisions at sqrt (s)=200 GeV

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    We report the STAR measurement of Phi meson production in Au+Au and p+p collisions at sqrt (s)=200 GeV. Using the event mixing technique, the Phi spectra and yields are obtained at mid-rapidity for five centrality bins in Au+Au collisions and for non-singly-diffractive p+p collisions. It is found that the Phi transverse momentum distributions from Au+Au collisions are better fitted with a single-exponential while the p+p spectrum is better described by a double-exponential distribution. The measured nuclear modification factors indicate that Phi production in central Au+Au collisions is suppressed relative to peripheral collisions when scaled by the number of binary collisions. The systematics of versus centrality and the constant Phi/K- ratio versus beam species, centrality, and collision energy rule out kaon coalescence as the dominant mechanism for Phi production.Comment: 6 pages, 3 figures, submitted to Phys. Rev. Let

    Azimuthal anisotropy and correlations in p+p, d+Au and Au+Au collisions at 200 GeV

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    We present the first measurement of directed flow (v1v_1) at RHIC. v1v_1 is found to be consistent with zero at pseudorapidities η\eta from -1.2 to 1.2, then rises to the level of a couple of percent over the range 2.4<η<42.4 < |\eta| < 4. The latter observation is similar to data from NA49 if the SPS rapidities are shifted by the difference in beam rapidity between RHIC and SPS. Back-to-back jets emitted out-of-plane are found to be suppressed more if compared to those emitted in-plane, which is consistent with {\it jet quenching}. Using the scalar product method, we systematically compared azimuthal correlations from p+p, d+Au and Au+Au collisions. Flow and non-flow from these three different collision systems are discussed.Comment: Quark Matter 2004 proceeding, 4 pages, 3 figure

    Azimuthal anisotropy: the higher harmonics

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    We report the first observations of the fourth harmonic (v_4) in the azimuthal distribution of particles at RHIC. The measurement was done taking advantage of the large elliptic flow generated at RHIC. The integrated v_4 is about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8) harmonics upper limits on the magnitudes are reported.Comment: 4 pages, 6 figures, contribution to the Quark Matter 2004 proceeding

    Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

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    Identified mid-rapidity particle spectra of π±\pi^{\pm}, K±K^{\pm}, and p(pˉ)p(\bar{p}) from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (RdAuR_{dAu}) between protons (p+pˉ)(p+\bar{p}) and charged hadrons (hh) in the transverse momentum range 1.2<pT<3.01.2<{p_{T}}<3.0 GeV/c is measured to be 1.19±0.051.19\pm0.05(stat)±0.03\pm0.03(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of (p+pˉ)/h(p+\bar{p})/h in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from transverse momentum 1.8 GeV/c to 3. GeV/

    Strange Resonance Production in p+p and Au+Au Collisions at RHIC Energies

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    Resonance yields and spectra from elementary p+p and Au+Au collisions at sNN=\sqrt{s_{\rm NN}} = 200 GeV from the STAR experiment at RHIC are presented and discussed in terms of chemical and thermal freeze-out conditions. Thermal models do not adequately describe the yields of the resonance production in central Au+Au collisions. The approach to include elastic hadronic interactions between chemical freeze-out and thermal freeze-out suggests a time of Δτ>\Delta \tau>5 fm/c.Comment: 4 pages, 7 figures, proceedings of the Quark Matter 2004, in Oakland, California, to be published in Journal of Physics G: Nuclear and Particle Physic

    Identified particles at large transverse momenta in STAR in Au+Au collisions @ sqrt(s_NN) = 200 GeV

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    We report measurements of the ratios of identified hadrons (pi,K,p,Lambda) in Au+Au collisions at sqrt(s_NN) = 200 GeV as a function of both collision centrality and transverse momentum (p_T). Ratios of anti-baryon to baryon yields are independent of p_T within 2<p_T <6 GeV/c indicating that, for such a range, our measurements are inconsistent with theoretical pQCD calculations predicting a decrease due to a stronger contribution from valence quark scattering. For both strange and non-strange species, a strong baryon enhancement relative to meson yields is observed as a function of collision centrality in this intermediate p_T region, leading to p/pi and Lambda/K ratios greater than unity. The nuclear modification factor, R_cp (central relative to peripheral collisions), is used to illustrate the interplay between jet quenching and hadron production. The physics implications of these measurements are discussed with reference to different theoretical models.Comment: 5 pages, 4 figures. Proceedings of Quark Matter 2004 Conference, Jan 2004, Oakland, USA. Submitted to Journal of Physics

    High-pTp_{T} electron distributions in d+Au and p+p collisions at RHIC

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    We present preliminary measurements of electron and positron spectra in d+Au and p+p collisions at sNN=200\sqrt{s_{NN}}=200 GeV for 1.5<pT<7.01.5 < p_{T} < 7.0 GeV/c. These measurements were carried out using the STAR Time Projection Chamber (TPC) and the Barrel Electromagnetic calorimeter (EMC). Overall hadron rejection factors in the range of 10510^{5} have been achieved. In this work we describe the measurement technique used to discriminate electrons from hadrons and compare the results for single electron spectra with Pythia based pQCD calculations for electrons from heavy-quark semi-leptonic decays.Comment: Quark Matter 2004 conference proceeding
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