535 research outputs found

    Ph.D. research output in STEM: the role of gender and race in supervision

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    We study whether student-advisor gender and race couples matter for publication productivity of Ph.D. students in South Africa. We consider the sample of all Ph.D.s in STEM graduating between 2000 and 2014, after the recent systematic introduction of doctoral programs in this country. We investigate the joint effects of gender and race for the whole sample and looking separately at the sub-samples of (1) whitewhite; (2) black-black; and (3) black-white student-advisor couples. We find early career productivity differences: while female students publish on average 10% to 20% fewer articles than males, this is true mainly for female students working with a male advisor, not for those working with a female one. These disparities are similar, though more pronounced, when looking at the joint effects of gender and race for the white-white and black-black student-advisor pairs. We also explore whether publication productivity differences change significantly for students with a high, medium, or low “productivity-profile”, and find that they are U-shaped. Female students with a high (or low) “productivity-profile” studying with female advisors are as productive than male students with a high (or low) “productivity-profile” studying with male advisor

    Long-Term Use of Cardiovascular Drugs Challenges for Research and for Patient Care

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    AbstractLittle is known about the benefits and risks of the long-term use of cardiovascular drugs. Evidence from randomized clinical trials (RCTs) rarely goes beyond a few years of follow-up, but patients are often given continuous treatment with multiple drugs well into old age. We focus on 4 commonly used cardiovascular drug classes: aspirin, statins, beta-blockers, and angiotensin-converting enzyme inhibitors given to patients after myocardial infarction. However, the issues raised apply more broadly to all long-term medications across cardiovascular diseases and the whole of medicine. The evidence and limitations of RCTs are addressed, as well as current practice in pre-licensing trials, the increasing problems of polypharmacy (especially in the elderly), the lack of trial evidence for withdrawal of drugs, the role of regulatory authorities and other stakeholders in this challenging situation, and the potential educational solutions for the medical profession. We conclude with a set of recommendations on how to improve the situation of long-term drug use

    Closure of the Clymene Ocean and formation of West Gondwana in the Cambrian: Evidence from the Sierras Australes of the southernmost Rio de la Plata craton, Argentina

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    The formation of Gondwana took place across a series of Brasiliano?Pan African suture zones that record late Neoproterozoic to earliest Paleozoic collisions between Precambrian cratons. In South America, an internal suture zone marks the disappearance of the Clymene Ocean that separated the Amazon craton from the São Francisco and Rio de la Plata cratons. New geochronological data from the southern end of this massive collision zone in the Sierras Australes of central-eastern Argentina document Paleoproterozoic crust and suggest an Ediacaran age for the oldest sedimentary rocks. These two observations extend the known limit of the Rio de la Plata craton at least 200 km SW of previous estimates. New data also confirm the occurrence oflate Ediacaran to late Cambrian magmatism in the Sierras Australes. The age of these hypabyssal to volcanic rocks corresponds to igneous events in the Pampean belt along the western margin of the Rio de la Plata craton, although the shallow levelmagma emplacement in the Sierra da Ventana study area contrasts with the deeply exhumed rocks of the Pampean orogeny type locality. These new age data are compared with a broad compilation of geochronological age Clymene collision belts to the north, the Paraguai and Araguaia belts. The close overlap of the timing of orogenesis indicates the age of Clymene ocean closure in its northern reaches. In the south, the Pampean belt was unconfined, allowing continued tectonic activity and crustal accretion throughout the Paleozoic.Fil: Tohver, E.. University of Western Australia; AustraliaFil: Cawood, P. P.. University of Western Australia; Australia. University of St. Andrews; Reino UnidoFil: Rossello, Eduardo Antonio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; ArgentinaFil: Jourdan, J.. Curtin University; Australi

    Orthorexia nervosa: A cross-sectional study among athletes competing in endurance sports in Northern Italy

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    Orthorexia Nervosa (ON) is an eating disorder marked by an excessive control over the quality of the food eaten. Some groups present a higher prevalence of ON and people practicing sports seems to be a population at risk. The aim of this study is to assess the prevalence of ON in endurance athletes and to compare their prevalence with the ones recorded in the sedentary population and in athletes playing other sports. A cross-sectional survey was carried in Piedmont and Valle d'Aosta, among 549 participants in local sports events aged between 18 and 40 years old. The questionnaire assessed socio-demographic characteristics, physical activity, nutrition and diet, the ORTO-15 questionnaire and Eating Habits Questionnaire (EHQ). The sample was stratified according to the minutes of sport practiced in a week and the type of sport played. Crosstab chi-square analyses to determine group differences on categorical variables (e.g. gender), and ANOVAs or t tests to determine group differences on continuous variables were performed. When required, post hoc analyses were performed. Linear and logistic regressions were performed in order to investigate potential predictors of orthorexia. The EHQ mean scores ware significantly higher in people who practice sports >150 minutes/week. EHQ score resulted to be positively correlated with endurance sport practice >150 minutes/week, with a coefficient of 2.407 (I.C.95% [0.27;4.54], p = 0.027). Analyses carried out suggested a correlation between endurance sport practice and ON. Further studies should be performed to identify diagnostic criteria and to compare different questionnaire used to assess them

    Azospirillum brasilense Az39 labeled with GFP in Arabidopsis thaliana roots

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    La cepa Az39 de Azospirillum brasilense fue aislada de rizosfera de trigo en la localidad de Marcos Juárez, Córdoba. Esta cepa fue seleccionada por su eficiencia para promover el crecimiento de este cultivo; se encuentra depositada en el Laboratorio de Bacterias Promotoras del Crecimiento Vegetal (BPCV) del IMYZA, INTA-Castelar, y forma parte de numerosos inoculantes comerciales recomendados en cultivos de cereales y otros. Su capacidad para estimular el crecimiento de las raíces e incrementar los rindes en especies como maíz, trigo, arroz y diversas hortícolas ha sido bien documentada mediante ensayos de invernáculo y de campo. También se ha informado su capacidad para mitigar los efectos adversos del estrés hídrico o salino en maíz y cebada.Fil: Díaz Herrera, Silvana Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Biológica; ArgentinaFil: Rossello, Florencia J.. Universidad Nacional de Quilmes; ArgentinaFil: Benavides, Maria Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Biológica; ArgentinaFil: Groppa, María Daniela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Biológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Zawoznik, Myriam Sara. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Biológica; Argentin

    Distinct ecotypes within a natural haloarchaeal population enable adaptation to changing environmental conditions without causing population sweeps

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    Microbial communities thriving in hypersaline brines of solar salterns are highly resistant and resilient to environmental changes, and salinity is a major factor that deterministically influences community structure. Here, we demonstrate that this resilience occurs even after rapid osmotic shocks caused by a threefold change in salinity (a reduction from 34 to 12% salts) leading to massive amounts of archaeal cell lysis. Specifically, our temporal metagenomic datasets identified two co-occurring ecotypes within the most dominant archaeal population of the brines Haloquadratum walsbyi that exhibited different salt concentration preferences. The dominant ecotype was generally more abundant and occurred in high-salt conditions (34%); the low abundance ecotype always co-occurred but was enriched at salinities around 20% or lower and carried unique gene content related to solute transport and gene regulation. Despite their apparent distinct ecological preferences, the ecotypes did not outcompete each other presumably due to weak functional differentiation between them. Further, the osmotic shock selected for a temporal increase in taxonomic and functional diversity at both the Hqr. walsbyi population and whole-community levels supporting the specialization-disturbance hypothesis, that is, the expectation that disturbance favors generalists. Altogether, our results provide new insights into how intraspecies diversity is maintained in light of substantial gene-content differences and major environmental perturbations
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