148 research outputs found
NEAR: A New Station to Study Neutron-Induced Reactions of Astrophysical Interest at CERN-n_TOF
We present NEAR, a new experimental area at the CERN-n_TOF facility and a possible setup for cross section measurements of interest to nuclear astrophysics. This was recently realized with the aim of performing spectral-averaged neutron-capture cross section measurements by means of the activation technique. The recently commissioned NEAR station at n_TOF is now ready for the physics program, which includes a preliminary benchmark of the proposed idea. Based on the results obtained by dedicated Monte Carlo simulations and calculation, a suitable filtering of the neutron beam is expected to enable measurements of Maxwellian Averaged Cross Section (MACS) at different temperatures. To validate the feasibility of these studies we plan to start the measurement campaign by irradiating several isotopes whose MACS at different temperatures have recently been or are planned to be determined with high accuracy at n_TOF, as a function of energy in the two time-of-flight measurement stations. For instance, the physical cases of 88Sr(n,γ
), 89Y(n,γ
), 94Zr(n,γ
) and 64Ni(n,γ
) are discussed. As the neutron capture on 89Y produces a pure β
-decay emitter, we plan to test the possibility to perform activation measurements on such class of isotopes as well. The expected results of these measurements would open the way to challenging measurements of MACS by the activation technique at n_TOF, for rare and/or exotic isotopes of interest for nuclear astrophysic
Tracking the emergence of disparities in the subnational spread of COVID-19 in Brazil using an online application for real-time data visualisation: A longitudinal analysis
Background: Brazil is one of the countries worst affected by the COVID-19 pandemic with over 20 million cases and 557,000 deaths reported by August 2021. Comparison of real-time local COVID-19 data between areas is essential for understanding transmission, measuring the effects of interventions, and predicting the course of the epidemic, but are often challenging due to different population sizes and structures. Methods: We describe the development of a new app for the real-time visualisation of COVID-19 data in Brazil at the municipality level. In the CLIC-Brazil app, daily updates of case and death data are downloaded, age standardised and used to estimate the effective reproduction number (Rt). We show how such platforms can perform real-time regression analyses to identify factors associated with the rate of initial spread and early reproduction number. We also use survival methods to predict the likelihood of occurrence of a new peak of COVID-19 incidence. Findings: After an initial introduction in S\~o Paulo and Rio de Janeiro states in early March 2020, the epidemic spread to northern states and then to highly populated coastal regions and the Central-West. Municipalities with higher metrics of social development experienced earlier arrival of COVID-19 (decrease of 11·1 days 95% CI:8.9,13.2 in the time to arrival for each 10% increase in the social development index). Differences in the initial epidemic intensity (mean Rt) were largely driven by geographic location and the date of local onset. Interpretation: This study demonstrates that platforms that monitor, standardise and analyse the epidemiological data at a local level can give useful real-time insights into outbreak dynamics that can be used to better adapt responses to the current and future pandemics. Funding: This project was supported by a Medical Research Council UK (MRC-UK) -S{\~{a}}o Paulo Research Foundation (FAPESP) CADDE partnership award (MR/S0195/1 and FAPESP 18/14389-0
Epigenetics and developmental programming of welfare and production traits in farm animals
The concept that postnatal health and development can be influenced by events that occur in utero originated from epidemiological studies in humans supported by numerous mechanistic (including epigenetic) studies in a variety of model species. Referred to as the ‘developmental origins of health and disease’ or ‘DOHaD’ hypothesis, the primary focus of large-animal studies until quite recently had been biomedical. Attention has since turned towards traits of commercial importance in farm animals. Herein we review the evidence that prenatal risk factors, including suboptimal parental nutrition, gestational stress, exposure to environmental chemicals and advanced breeding technologies, can determine traits such as postnatal growth, feed efficiency, milk yield, carcass composition, animal welfare and reproductive potential. We consider the role of epigenetic and cytoplasmic mechanisms of inheritance, and discuss implications for livestock production and future research endeavours. We conclude that although the concept is proven for several traits, issues relating to effect size, and hence commercial importance, remain. Studies have also invariably been conducted under controlled experimental conditions, frequently assessing single risk factors, thereby limiting their translational value for livestock production. We propose concerted international research efforts that consider multiple, concurrent stressors to better represent effects of contemporary animal production systems
Wage inequality, segregation by skill and the price of capital in an assignment model
Some pieces of empirical evidence suggest that in the U.S., over the last few decades, (i) wage inequality between-plants has risen much more than wage inequality within-plants and (ii) there has been an increase in the segregation of workers by skill into separate plants. This paper presents a frictionless assignment model in which these two features can be explained simultaneously as the result of the decline in the relative price of capital. Additional implications of the model regarding the skill premium and the dispersion in labor productivity across plants are also consistent with the empirical evidence. [resumen de autor
Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study
Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe
Hypertriton Production in p-Pb Collisions at √sNN = 5.02 TeV
The study of nuclei and antinuclei production has proven to be a powerful
tool to investigate the formation mechanism of loosely bound states in
high-energy hadronic collisions. The first measurement of the production of
in p-Pb collisions at = 5.02
TeV is presented in this Letter. Its production yield measured in the rapidity
interval -1 < y < 0 for the 40% highest multiplicity p-Pb collisions is . The measurement is compared with the expectations of statistical
hadronisation and coalescence models, which describe the nucleosynthesis in
hadronic collisions. These two models predict very different yields of the
hypertriton in small collision systems such as p-Pb and therefore the
measurement of is crucial to distinguish between them.
The precision of this measurement leads to the exclusion with a significance
larger than 6 of some configurations of the statistical hadronisation,
thus constraining the production mechanism of loosely bound states
K∗(892)0 and φ(1020) production in p-Pb collisions at √s NN = 8.16 TeV
The production of K*(892)(0) and phi(1020) resonances has been measured in p-Pb collisions at root s(NN) = 8.16 TeV using the ALICE detector. Resonances are reconstructed via their hadronic decay channels in the rapidity interval -0.5 8 GeV/c), the R-pPb values of all hadrons are consistent with unity within uncertainties. The R-pPb of K*(892)(0) and phi(1020) at root s(NN) = 8.16 and 5.02 TeV show no significant energy dependence
General balance functions of identified charged hadron pairs of (pi,K,p) in Pb-Pb collisions at 2.76 TeV
First measurements of balance functions (BFs) of all combinations of identified charged hadron ( π , K, p)
pairs in Pb–Pb collisions at √sNN = 2.76 TeV recorded by the ALICE detector are presented. The BF
measurements are carried out as two-dimensional differential correlators versus the relative rapidity
(delta-y) and azimuthal angle (delta-φ) of hadron pairs, and studied as a function of collision centrality. The delta-φ
dependence of BFs is expected to be sensitive to the light quark diffusivity in the quark–gluon plasma.
While the BF azimuthal widths of all pairs substantially decrease from peripheral to central collisions, the
longitudinal widths exhibit mixed behaviors: BFs of π π and cross-species pairs narrow significantly in
more central collisions, whereas those of KK and pp are found to be independent of collision centrality.
This dichotomy is qualitatively consistent with the presence of strong radial flow effects and the existence
of two stages of quark production in relativistic heavy-ion collisions. Finally, the first measurements of
the collision centrality evolution of BF integrals are presented, with the observation that charge balancing
fractions are nearly independent of collision centrality in Pb–Pb collisions. Overall, the results presented
provide new and challenging constraints for theoretical models of hadron production and transport in
relativistic heavy-ion collisions
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