8 research outputs found

    A Precision Measurement of the Neutron Twist-3 Matrix Element d2nd_2^n: Probing Color Forces

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    Double-spin asymmetries and absolute cross sections were measured at large Bjorken xx (0.25 x \le x \le 0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized 3^3He target. In this dedicated experiment, the spin structure function g2g_2 on 3^3He was determined with precision at large xx, and the neutron twist-three matrix element d2nd_2^n was measured at \left of 3.21 and 4.32 GeV2^2/c2c^2, with an absolute precision of about 10510^{-5}. Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at \left = 5 GeV2^2/c2c^2. Combining d2nd_2^n and a newly extracted twist-four matrix element, f2nf_2^n, the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 30 MeV/fm in magnitude.Comment: Corrected a typo in the author list and Figure 1 legend. 6 pages, 2 figures, 2 table

    Comparative yield loss estimates due to blast in some upland rice cultivars.

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    Leaf and panicle blast severities and grain yield of some upland rice cultivars were measured in three successive years in field plots unprotected or protected with fungicides. The variation in disease severities in different plots was used to establish relationships between severity of leaf and panicle blast and yield. Linear multiple regression equations for each cultivar by year were developed to estimate the yield decrease in different cultivars per unit increase in disease. Leaf blast severities at maximum tillering or booting stage and panicle blast 25 days after heading accounted for variation in grain yield in most of the cultivars. General equations combining five early and eight medium-duration rice cultivars were developed. The estimated percentage losses in grain yield due to blastwere 2.7 and 1.5 for one percent increase in blast in the early and medium-duration cultivars, respectively

    Polarization Components in π0 Photoproduction at Photon Energies up to 5.6 GeV

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    We present new data for the polarization observables of the final state proton in the 1H(γ⃗,p⃗)π[superscript 0] reaction. These data can be used to test predictions based on hadron helicity conservation and perturbative QCD. These data have both small statistical and systematic uncertainties and were obtained with beam energies between 1.8 and 5.6 GeV and for π[superscript 0] scattering angles larger than 75° in the center-of-mass frame. The data extend the polarization measurements database for neutral pion photoproduction up to Eγ=5.6  GeV. The results show a nonzero induced polarization above the resonance region. The polarization transfer components vary rapidly with the photon energy and π[superscript 0] scattering angle in the center-of-mass frame. This indicates that hadron helicity conservation does not hold and that the perturbative QCD limit is still not reached in the energy regime of this experiment.United States. Dept. of Energy (contract no. DE-AC05-06OR23177)National Science Foundation (U.S.)

    Rosenbluth separation of the π0\pi^0 Electroproduction Cross Section off the Neutron

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    International audienceWe report the first longitudinal-transverse separation of the deeply virtual exclusive π0 electroproduction cross section off the neutron and coherent deuteron. The corresponding four structure functions dσL/dt, dσT/dt, dσLT/dt, and dσTT/dt are extracted as a function of the momentum transfer to the recoil system at Q2=1.75  GeV2 and xB=0.36. The ed→edπ0 cross sections are found compatible with the small values expected from theoretical models. The en→enπ0 cross sections show a dominance from the response to transversely polarized photons, and are in good agreement with calculations based on the transversity generalized parton distributions of the nucleon. By combining these results with previous measurements of π0 electroproduction off the proton, we present a flavor decomposition of the u and d quark contributions to the cross section

    Population-level risks of alcohol consumption by amount, geography, age, sex, and year: a systematic analysis for the Global Burden of Disease Study 2020

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    Background The health risks associated with moderate alcohol consumption continue to be debated. Small amounts of alcohol might lower the risk of some health outcomes but increase the risk of others, suggesting that the overall risk depends, in part, on background disease rates, which vary by region, age, sex, and year. Methods For this analysis, we constructed burden-weighted dose-response relative risk curves across 22 health outcomes to estimate the theoretical minimum risk exposure level (TMREL) and non-drinker equivalence (NDE), the consumption level at which the health risk is equivalent to that of a non-drinker, using disease rates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2020 for 21 regions, including 204 countries and territories, by 5-year age group, sex, and year for individuals aged 15-95 years and older from 1990 to 2020. Based on the NDE, we quantified the population consuming harmful amounts of alcohol. Findings The burden-weighted relative risk curves for alcohol use varied by region and age. Among individuals aged 15-39 years in 2020, the TMREL varied between 0 (95% uncertainty interval 0-0) and 0.603 (0.400-1.00) standard drinks per day, and the NDE varied between 0.002 (0-0) and 1.75 (0.698-4.30) standard drinks per day. Among individuals aged 40 years and older, the burden-weighted relative risk curve was J-shaped for all regions, with a 2020 TMREL that ranged from 0.114 (0-0.403) to 1.87 (0.500-3.30) standard drinks per day and an NDE that ranged between 0.193 (0-0.900) and 6.94 (3.40-8.30) standard drinks per day. Among individuals consuming harmful amounts of alcohol in 2020, 59.1% (54.3-65.4) were aged 15-39 years and 76.9% (73.0-81.3) were male. Interpretation There is strong evidence to support recommendations on alcohol consumption varying by age and location. Stronger interventions, particularly those tailored towards younger individuals, are needed to reduce the substantial global health loss attributable to alcohol

    The global burden of cancer attributable to risk factors, 2010-19: a systematic analysis for the Global Burden of Disease Study 2019

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    Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% 47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% 32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% 27.9-42.8] and 33.3% 25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license
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