957 research outputs found

    Back by popular demand: the benefits of traditional vegetables: One community's story

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    Agricultural biodiversity - the varieties of plants, animals and microorganisms used to benefit people - is critical for improving the nutrition and health of the urban and rural poor. The lack of micronutrients, including certain vitamins, minerals and other components needed for a healthy diet, is a pervasive and growing threat throughout the world. One result of this 'hidden hunger' has been a spectacular rise in obesity, heart disease, type II diabetes and various cancers, especially in developing countries, where many people have adopted an oversimplified diet based on the cheapest refined carbohydrates and fats. So-called neglected or underused crops are often an important source of nutrition as well as being adapted to the marginal environments in which they grow. And yet, a lack of scientific research and development has limited the appreciation of their benefits. Over time, local communities have tended to replace these plants with more prestigious introduced crops that are often less nutritious and less suited to local climate and soils. For example, communities in the high Andean mountains of South America have traditionally consumed several types of Andean grains. The most popular include quinoa, cañihua, amaranth and chocho (also known as tarwi). Like most traditional species, Andean grains are extremely nutritious and hardier than many commercial crops. They are rich in protein and essential amino acids. The leaves contain high levels of protein and iron, which is easily absorbed thanks to the high level of vitamin C that is also present. Andean grains are also easily digested, making them particularly suitable for babies, children and elderly people. Nevertheless, these grains have suffered a decline in status, especially in urban areas, where they have been replaced with cheaper, less nutritious foods such as pasta and rice. Like Andean grains, the minor millets of South Asia are very nutritious and well suited to marginal lands. Yet they too suffer from low status, which makes it difficult to sell them to modern consumers.African leafy vegetables have suffered the same decline in status as these and other traditional crops. About 900 species of leafy vegetables grow in sub-Saharan Africa. These plants were once a key part of people's diets and culture. Women grew the vegetables in their gardens, providing yearround supplies of nutritious foods to supplement the family diet. Then foreign crops such as cabbage and carrots were introduced. Because of their exotic origins, these new crops acquired a special status and came to symbolize modernity. Communities gradually stopped growing traditional leafy vegetables in their gardens, and began to grow the lucrative - though less nutritious - 'modern' crops instead. This booklet describes how reintroducing traditional leafy vegetables had an impact on the lives of people in a community near Nairobi, Kenya, thanks largely to the inspiration of one farmer

    Syndemic Health Disparities and Sexually Transmitted Infection Burden Among Black Men Who Have Sex with Men Engaged in Sex Work in the U.S.

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    Black men who have sex with men (MSM) engaged in sex work (BMSM-SW) experience elevated HIV and sexually transmitted infection (STI) prevalence. Further, BMSM-SW have been shown to have higher rates of syndemic psychosocial health conditions which contribute to HIV risk behavior and incidence, and poorer care outcomes than other groups of men who have sex with men. However, syndemic perspectives have not been applied to understanding past-year STI burden among BMSM-SW in the U.S. Sexually active Black MSM ≥ 18 years old were recruited from Black Pride events in six U.S. cities (n = 4421) between 2014 and 2017. Multivariable logistic regressions assessed correlates of past-year sex work engagement; whether BMSM-SW had higher odds of syndemic conditions; and whether BMSM-SW had higher odds of self-reported, past-year STI diagnoses. Structural equation models assessed relationships between sex work engagement, syndemic conditions, and STI controlled for sociodemographics and number of sexual partners. A total of 254 (5.7%) Black MSM reported past-year sex work, of whom 45.3% were HIV positive. BMSM-SW were significantly more likely to be Hispanic, to report past-year bisexual behavior, and to report annual income < $10,000. In multivariable models, BMSM-SW were significantly more likely to report intimate partner violence, assault victimization, polydrug use, and depression symptoms; they were also more likely to report past-year gonorrhea, chlamydia, and syphilis. Syndemic conditions mediated the relationship between past-year sex work and past-year STI burden, constituting a significant indirect effect. BMSM-SW in the U.S. face severe biopsychosocial health disparities. Interventions developed for BMSM engaged in sex work are lacking. Our results suggest that interventions containing safer sex work education and sex-positive biobehavioral HIV/STI prevention alongside substance use, mental health, employment, and education components will be most effective

    Causal categories: relativistically interacting processes

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    A symmetric monoidal category naturally arises as the mathematical structure that organizes physical systems, processes, and composition thereof, both sequentially and in parallel. This structure admits a purely graphical calculus. This paper is concerned with the encoding of a fixed causal structure within a symmetric monoidal category: causal dependencies will correspond to topological connectedness in the graphical language. We show that correlations, either classical or quantum, force terminality of the tensor unit. We also show that well-definedness of the concept of a global state forces the monoidal product to be only partially defined, which in turn results in a relativistic covariance theorem. Except for these assumptions, at no stage do we assume anything more than purely compositional symmetric-monoidal categorical structure. We cast these two structural results in terms of a mathematical entity, which we call a `causal category'. We provide methods of constructing causal categories, and we study the consequences of these methods for the general framework of categorical quantum mechanics.Comment: 43 pages, lots of figure

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

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    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

    Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

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    A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.Comment: 7 pages plus author list (18 pages total), 2 figures, 4 tables, final version published in Physics Letters
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