The puzzling symbiotic X-ray system 4U1700+24

Symbiotic X-ray binaries form a subclass of low-mass X-ray binary systems consisting of a neutron star accreting material from a red giant donor star via stellar wind or Roche lobe overflow. Only a few confirmed members are currently known; 4U 1700+24 is a good candidate as it is a relatively bright X-ray object, possibly associated with the late-type star V934 Her. We analysed the archive {\it XMM}-Newton and Swift/XRT observations of 4U 1700+24 in order to have a uniform high-energy ($0.3-10$ keV) view of the source. We confirmed the existence of a red-shifted O VIII Ly-$\alpha$ transition (already observed in the 2002 {\it XMM}-Newton data) in the high-resolution spectra collected via the RGS instruments. The red-shift of the line is found in all the analysed observations and, on average, it was estimated to be $\simeq 0.009$. We also observed a modulation of the centroid energy of the line on short time scales (a few days) and discuss the observations in the framework of different scenarios. If the modulation is due to the gravitational red-shift of the neutron star, it might arise from a sudden re-organization of the emitting $X$-ray matter on the scale of a few hundreds of km. Alternatively, we are witnessing a uni-polar jet of matter (with typical velocity of $1000-4000$ km s$^{-1}$) possibly emitted by the neutron star in an almost face-on system. The second possibility seems to be required by the apparent lack of any modulation in the observed $X$-ray light curve. We also note also that the low-resolution spectra (both {\it XMM}-Newton and Swift/XRT in the $0.3-10$ keV band) show the existence of a black body radiation emitted by a region (possibly associated with the neutron star polar cap) with typical size from a few tens to hundreds of meters. The size of this spot-like region reduces as the overall luminosity of 4U 1700+24 decreases.Comment: In press on A&

Os vinte principais mercados para exportação agrícola no futuro.

O objetivo deste trabalho é identificar e classificar quais serão os 20 maiores mercados mundiais importadores de produtos agrícolas e agroindustriais, bem como indicar os produtos brasileiros com maior potencial de exportação para cada um desses mercados. Para tanto, utilizou-se a lista dos 20 maiores importadores desses produtos, no ano de 2010, e aplicaram-se 11 indicadores de ordem econômica, financeira e social para se obter a classificação dos mercados mais interessantes como importadores. As fontes dos dados foram: Estatísticas de Comercio Exterior do Agronegócio Brasileiro (Agrostat), Trade Statistics for International Business Development (Trademap), World Economic OutLook Data Base, do Fundo Monetário Internacional, Doing Business, do Banco Mundial, e Programa das Nações Unidas para o Desenvolvimento (Pnud). Os resultados indicaram os 20 mais interessantes mercados mundiais para efeito de priorização das exportações dos mencionados produtos, no presente e no futuro, bem como os países para os quais as exportações brasileiras podem aumentar

Cardiac surgery practice during the COVID-19 outbreak: A regionwide survey

Background: Health systems worldwide have been overburdened by the "COVID-19 surge". Consequently, strategies to remodulate non-COVID medical and surgical care had to be developed. Knowledge of the impact of COVID surge on cardiac surgery practice is mainstem. Present study aims to evaluate the regional practice pattern during lockdown in Campania. Methods: A multicenter regional observational 26-question survey was conducted, including all adult cardiac surgery units in Campania, Italy, to assess how surgical practice has changed during COVID-19 national lockdown. Results: All centers adopted specific protocols for screening patients and personnel. A significant reduction in the number of dedicated intensive care unit (ICU) beds (-30.0%±38.1%, range: 0-100%) and cardiac operating rooms (-22.2%±26.4%, range: 0-50%) along with personnel relocation to other departments was disclosed (anesthesiologists -5.8%±11.1%, range: 0-33.3%; perfusionists -5.6%±16.7%, range: 0-50%; nurses -4.8%±13.2%, range: 0-40%; cardiologists -3.2%±9.5%, range: 0-28.6%). Cardiac surgeons were never reallocated to other services. Globally, we witnessed dramatically lower adult cardiac surgery case volumes (335 vs. 667 procedures, P<0.001), as institutions and surgeons followed guidelines to curtail non-urgent operations. Conclusions: This regional survey demonstrates major changes in practice as a response to the COVID-19 pandemic. In this respect, this experience might lead to the development of permanent systems-based plans for future pandemic and may effectively help policy decision making when prioritizing healthcare resource reallocation during and after the pandemic

An Experimentalist's View of Neutrino Oscillations

Neutrinos, and primarily neutrino oscillations, have undoubtedly been one of the most exciting topics in the field of high-energy physics over the past few years. The existence of neutrino oscillations would require an extension of the currently accepted description of sub-nuclear phenomena beyond the Standard Model. Compelling evidence of new physics, which seems to be pointing towards neutrino oscillations, is coming from the solar neutrino deficit and from the atmospheric neutrino anomaly. More controversial effects have been observed with artificially produced neutrinos. The present experimental status of neutrino oscillations is reviewed, as well as the planned future experimental programme, which, it is hoped, will solve most of the outstanding puzzles.Comment: 64 pages, 29 figures, to be published in Intern. J. Mod. Phys. A (2001

The effectiveness of intervening on social isolation to reduce mortality during heat waves in aged population: a retrospective ecological study

Background: Heat waves are correlated with increased mortality in the aged population. Social isolation is known as a vulnerability factor. This study aims at evaluating the correlation between an intervention to reduce social isolation and the increase in mortality in the population over 80 during heat waves. Methods: This study adopted a retrospective ecologic design. We compared the excess mortality rate (EMR) in the over-80 population during heat waves in urban areas of Rome (Italy) where a program to reduce social isolation was implemented, to others where it was not implemented. We measured the mortality of the summer periods from 2015 to 2019 compared with 2014 (a year without heat waves). Winter mortality, cadastral income, and the proportion of people over 90 were included in the multivariate Poisson regression. Results: The EMR in the intervention and controls was 2.70% and 3.81%, respectively. The rate ratio was 0.70 (c.i. 0.54–0.92, p-value 0.01). The incidence rate ratio (IRR) of the interventions, with respect to the controls, was 0.76 (c.i. 0.59–0.98). After adjusting for other variables, the IRR was 0.44 (c.i. 0.32–0.60). Conclusions: Reducing social isolation could limit the impact of heat waves on the mortality of the elderly population

Panorâma sócio-econômico e evidências ambientais de impactos decorrentes da pressão antrópica pela expansão da cultura do açaí (Euterpe oleracea) na ilha do Murutucu, Pará.

No presente trabalho investigou-se aspectos que evidenciassem respostas ambientais à pressão antrópica decorrente da expansão do açaí na ilha de Murutucu para subsidiar ações conservacionistas na área de estudo