The growth factor of matter perturbations in an f(R) gravity

The growth of matter perturbations in the $f(R)$ model proposed by Starobinsky is studied in this paper. Three different parametric forms of the growth index are considered respectively and constraints on the model are obtained at both the $1\sigma$ and $2\sigma$ confidence levels, by using the current observational data for the growth factor. It is found, for all the three parametric forms of the growth index examined, that the Starobinsky model is consistent with the observations only at the $2\sigma$ confidence level.Comment: 15 pages, 5 figure

Prompt K_short production in pp collisions at sqrt(s)=0.9 TeV

The production of K_short mesons in pp collisions at a centre-of-mass energy of 0.9 TeV is studied with the LHCb detector at the Large Hadron Collider. The luminosity of the analysed sample is determined using a novel technique, involving measurements of the beam currents, sizes and positions, and is found to be 6.8 +/- 1.0 microbarn^-1. The differential prompt K_short production cross-section is measured as a function of the K_short transverse momentum and rapidity in the region 0 < pT < 1.6 GeV/c and 2.5 < y < 4.0. The data are found to be in reasonable agreement with previous measurements and generator expectations.Comment: 6+18 pages, 6 figures, updated author lis

A História da Alimentação: balizas historiográficas

Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

Background: Many patients with COVID-19 have been treated with plasma containing anti-SARS-CoV-2 antibodies. We aimed to evaluate the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19. Methods: This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. The trial is underway at 177 NHS hospitals from across the UK. Eligible and consenting patients were randomly assigned (1:1) to receive either usual care alone (usual care group) or usual care plus high-titre convalescent plasma (convalescent plasma group). The primary outcome was 28-day mortality, analysed on an intention-to-treat basis. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings: Between May 28, 2020, and Jan 15, 2021, 11558 (71%) of 16287 patients enrolled in RECOVERY were eligible to receive convalescent plasma and were assigned to either the convalescent plasma group or the usual care group. There was no significant difference in 28-day mortality between the two groups: 1399 (24%) of 5795 patients in the convalescent plasma group and 1408 (24%) of 5763 patients in the usual care group died within 28 days (rate ratio 1·00, 95% CI 0·93–1·07; p=0·95). The 28-day mortality rate ratio was similar in all prespecified subgroups of patients, including in those patients without detectable SARS-CoV-2 antibodies at randomisation. Allocation to convalescent plasma had no significant effect on the proportion of patients discharged from hospital within 28 days (3832 [66%] patients in the convalescent plasma group vs 3822 [66%] patients in the usual care group; rate ratio 0·99, 95% CI 0·94–1·03; p=0·57). Among those not on invasive mechanical ventilation at randomisation, there was no significant difference in the proportion of patients meeting the composite endpoint of progression to invasive mechanical ventilation or death (1568 [29%] of 5493 patients in the convalescent plasma group vs 1568 [29%] of 5448 patients in the usual care group; rate ratio 0·99, 95% CI 0·93–1·05; p=0·79). Interpretation: In patients hospitalised with COVID-19, high-titre convalescent plasma did not improve survival or other prespecified clinical outcomes. Funding: UK Research and Innovation (Medical Research Council) and National Institute of Health Research

Influence of perches and footpad dermatitis on tonic immobility and heterophil to lymphocyte ratio of chickens

The purpose of the present study was to analyze the effect of perches and footpad dermatitis on stress and fear levels of chickens. In experiment 1 heterophil to lymphocyte ratio and tonic immobility duration were measured in 36-wk-old hens (36 birds) from 2 Spanish breeds of chickens (Black Menorca and Quail Castellana) housed in pens with or without perches from 20 wk of age. There was a significant difference in the heterophil to lymphocyte ratio between perch treatments (P < 0.05), the ratio of hens with perches being lower than that of hens without perches. Hens with perches had significant lymphophilia (P < 0.05). There was no significant difference for the duration of tonic immobility between hens with or without perches. Thus, hens with perches were less stressed than hens without perches, as indicated by the heterophil to lymphocyte ratio. Heterophil to lymphocyte ratio and heterophil number for Black Menorcas were significantly smaller (P < 0.001) than for Quail Castellanas, whereas lymphocyte number was greater in Black Menorcas. The Black Menorca hens had significantly (P < 0.01) shorter tonic immobility duration. In experiment 2 heterophil to lymphocyte ratio and tonic immobility duration were measured in 52-wk-old cocks (36 birds) of each of two different Spanish breeds of chickens (Black Barred Andaluza and Red Barred Vasca) housed in cages from 36 wk of age and showing or not showing footpad dermatitis. There was no significant effect of footpad dermatitis on the heterophil to lymphocyte ratio, its numerator, or its denominator, whereas there was significant effect on tonic immobility duration (P < 0.05) with tonic immobility of cocks with footpad dermatitis being longer than that of cocks without footpads. Thus, cocks with footpad dermatitis were more fearful than cocks without footpad dermatitis, as indicated by the tonic immobility duration. Heterophil to lymphocyte ratio and heterophil number were significantly smaller (P < 0.05) for Black Barred Andaluzas than for the Red Barred Vascas. ©2005 Poultry Science Association, Inc