Viscous dark fluid universe

We investigate the cosmological perturbation dynamics for a universe consisting of pressureless baryonic matter and a viscous fluid, the latter representing a unified model of the dark sector. In the homogeneous and isotropic background the \textit{total} energy density of this mixture behaves as a generalized Chaplygin gas. The perturbations of this energy density are intrinsically non-adiabatic and source relative entropy perturbations. The resulting baryonic matter power spectrum is shown to be compatible with the 2dFGRS and SDSS (DR7) data. A joint statistical analysis, using also Hubble-function and supernovae Ia data, shows that, different from other studies, there exists a maximum in the probability distribution for a negative present value $q_0 \approx - 0.53$ of the deceleration parameter. Moreover, while previous descriptions on the basis of generalized Chaplygin gas models were incompatible with the matter power spectrum data since they required a much too large amount of pressureless matter, the unified model presented here favors a matter content that is of the order of the baryonic matter abundance suggested by big-bang nucleosynthesis.Comment: 19 pages, 6 figure

Viscous dark fluid Universe: a unified model of the dark sector?

The Universe is modeled as consisting of pressureless baryonic matter and a bulk viscous fluid which is supposed to represent a unified description of the dark sector. In the homogeneous and isotropic background the \textit{total} energy density of this mixture behaves as a generalized Chaplygin gas. The perturbations of this energy density are intrinsically nonadiabatic and source relative entropy perturbations. The resulting baryonic matter power spectrum is shown to be compatible with the 2dFGRS and SDSS (DR7) data. A joint statistical analysis, using also Hubble-function and supernovae Ia data, shows that, different from other studies, there exists a maximum in the probability distribution for a negative present value of the deceleration parameter. Moreover, the unified model presented here favors a matter content that is of the order of the baryonic matter abundance suggested by big-bang nucleosynthesis. A problem of simple bulk viscous models, however, is the behavior of the gravitational potential and the reproduction of the CMB power spectrum.Comment: 12 pages, 3 figures, contributed paper to 8th Friedmann Seminar, 30 May to 3 June 2011, Rio de Janeiro, Brazi

Complicações Cardiovasculares Associadas à Infeção por COVID-19

Introduction: Reports of cardiovascular complications related to the COVID-19 infection have been frequent. Methods: Narrative review for relevant articles on the topic. The classic cardiovascular risk factors, like age, obesity, diabetes, and hypertension are associated with adverse outcomes in COVID-19 patients. Cardiovascular complications can have a diverse clinical presentation including silent myocardial injury, acute coronary syndromes, thromboembolism, cardiac arrhythmias, and heart failure. There are multiple mechanisms of cardiac injury that are not mutually exclusive. The approach to diagnosis and management should be carried out according to usual practice, while considering the particularities of COVID-19 infection. Conclusion: The interaction between SARS-CoV-2 and the heart is complex and is manifested in multiple ways. Regardless of the clinical presentation, cardiac complications convey a worse prognosis. Patients should be actively monitored and treated accordingly.info:eu-repo/semantics/publishedVersio

Porta enxertos para ameixeira.

Este capítulo tem o objetivo de compilar resultados de pesquisas e informações técnicas de alguns dos principais países produtores no que diz respeito ao comportamento de porta-enxertos indicados para a cultura da ameixeira

Cosmography from well-localized Fast Radio Bursts

Fast Radio Bursts (FRBs) are millisecond-duration pulses occurring at cosmological distances that have emerged as prominent cosmological probes due to their dispersion measure (DM) evolution with redshift. In this work, we use cosmography, a model-independent approach to describe the evolution of the universe, to introduce the cosmographic expansion of the DM-z relation. By fitting two different models for the intergalactic medium and host contributions to a sample of 23 well-localized FRBs, we estimate the kinematic parameters $q_0=-0.59 \substack{+0.20 \\ -0.17}$, $j_0=1.08 \substack{+0.62 \\ -0.56}$, $s_0=-2.1\pm7.0$, and $H_0=69.4\pm4.7$ achieving a precision of $6\%$ and $7\%$ for the Hubble constant depending on the models used for contributions. Furthermore, we demonstrate that this approach can be used as an alternative and complementary cosmological-model independent method to revisit the long-standing "Missing Baryons" problem in astrophysics by estimating that $82\%$ of the baryonic content of the universe resides in the intergalactic medium, within $7\%$ and $8\%$ precision, according to the contribution models considered here. Our findings highlight the potential of FRBs as a valuable tool in cosmological research and underscore the importance of ongoing efforts to improve our understanding of these enigmatic events

Propriedades físicas e infiltração de água de um Latossolo Vermelho Amarelo (Oxisol) do noroeste do estado de São Paulo, Brasil, sob três condições de uso e manejo

This study presents the results obtained in a field experiment carried out at Glicério, Northwest of São Paulo state, Brazil, whose objective was to analyze changes of selected soil physical properties and water infiltration rates on a Yellow-Red Latosol, under three different management conditions. The experimental design was arranged as completely randomized split-block with twelve treatments, which corresponded to four depths (0-0.05 m; 0.05-0.10 m; 0.10-0.20 m and 0.20-0.40 m) and three conditions of soil use and management with four replications. The soil surface conditions were: conventional tillage (one disking with moulboard plus two levelling passes with harrow), nine months before starting filed experiences; recent conventional tillage (also one disking with moulboard plus two levelling passes with harrow) and native forest. The conventional tillage areas were cropped for about fifteen years with annual cultures. The considered soil general physical properties were: macroporosity, microporosity, total porosity, bulk density, soil moisture and penetration resistance and, in addition; soil water infiltration rates were also recorded. According to our results, differences on general soil physical properties and infiltration rates appeared when both tilled sub-treatments and native forest were compared. Both, plots recently prepared by conventional tillage and those prepared by tillage but left nine months in rest, presented a statistically significant decrease of constant (final) water infiltration rates of 92.72% and 91.91% when compared with native forest plots

End-users’ perspectives of an eHealth platform to promote physical activity in COPD: a qualitative study

Introduction: eHealth platforms can be used as a tool to promote physical activity (PA) in patients with COPD. When developing such platforms, a bottom-up approach is needed to ensure that patients’ and healthcare professionals’ (HCP) needs and expectations are addressed. Aim: To assess patients’ and HCP’ perspectives on the ideal eHealth platform (web application - app - for HCP + mobile app for patients) for PA promotion in patients with COPD. Methods: One focus group with 5 patients (68±8 yrs, FEV1 44±21pp) and 6 individual interviews with HCP (physicians and physiotherapist, 39±10 yrs) were conducted using a semi-structured interview guide. Interviews were recorded and transcripts were analysed using the Grounded Theory approach. Results: Participants considered an eHealth platform to promote patients' PA valuable. Both groups suggested that PA should be individualised according to patients’ characteristics. The main features for a mobile app included: shared goal setting, PA progress graphs, motivational messages and goal badges, notifications, a bi-directional communication system to support patients and information on breathing exercises. Both groups highlighted the importance of measuring steps, PA duration, SpO2, and dyspnoea on exertion. For the web app, the HCP highlighted the importance of a notification system to signal PA changes or non-compliance (e.g., colour scheme), as well as tabs for PA goal setting and monitoring. HCP recommended this platform for patients with stable or mild disease and/or those attending pulmonary rehabilitation. Conclusion: Findings provide guidance to the design of future eHealth platforms for PA promotion in COPD.publishe

In-situ Micro-Raman spectroscopic analysis of Handprints in Maltravieso Cave (Cáceres), Spain

TECHNART 2015 − Catania, April 27 - 30, 2015; http://technart2015.lns.infn.it/Peer Reviewe