32 research outputs found

    Bulk viscous cosmology with causal transport theory

    Full text link
    We consider cosmological scenarios originating from a single imperfect fluid with bulk viscosity and apply Eckart's and both the full and the truncated M\"uller-Israel-Stewart's theories as descriptions of the non-equilibrium processes. Our principal objective is to investigate if the dynamical properties of Dark Matter and Dark Energy can be described by a single viscous fluid and how such description changes when a causal theory (M\"uller-Israel-Stewart's, both in its full and truncated forms) is taken into account instead of Eckart's non-causal theory. To this purpose, we find numerical solutions for the gravitational potential and compare its behaviour with the corresponding LambdaCDM case. Eckart's and the full causal theory seem to be disfavoured, whereas the truncated theory leads to results similar to those of the LambdaCDM model for a bulk viscous speed in the interval 10^{-11} << c_b^2 < 10^{-8}. Tentatively relating such value to a square propagation velocity of the order of T/m of perturbations in a non-relativistic gas of particles with mass m at the epoch of matter-radiation equality, this may be compatible with a mass range 0.1 GeV < m << 100 GeV.Comment: 23 pages, 7 figure

    Lyra's Cosmology of Massive String in Anisotropic Bianchi-II Space-time

    Full text link
    The paper deals with a spatially homogeneous and totally anisotropic Bianchi II cosmological models representing massive strings in normal gauge for Lyra's manifold. The modified Einstein's field equations have been solved by applying variation law for Hubble's parameter. This law generates two type of solutions for average scale factor, one is of power law type and other is of exponential law type. The power law describes the dynamics of Universe from big bang to present epoch while exponential law seems reasonable to project dynamics of future Universe. It has been found that the displacement actor (β)(\beta) is a decreasing function of time and it approaches to small positive value at late time, which is collaborated with Halford (1970) as well as recent observations of SN Ia. The study reveals that massive strings dominate in early Universe and eventually disappear from Universe for sufficiently large time, which is in agreement with the current astronomical observations.Comment: 12 pages, 5 figure

    Association of Candidate Gene Polymorphisms With Chronic Kidney Disease: Results of a Case-Control Analysis in the Nefrona Cohort

    Get PDF
    Chronic kidney disease (CKD) is a major risk factor for end-stage renal disease, cardiovascular disease and premature death. Despite classical clinical risk factors for CKD and some genetic risk factors have been identified, the residual risk observed in prediction models is still high. Therefore, new risk factors need to be identified in order to better predict the risk of CKD in the population. Here, we analyzed the genetic association of 79 SNPs of proteins associated with mineral metabolism disturbances with CKD in a cohort that includes 2, 445 CKD cases and 559 controls. Genotyping was performed with matrix assisted laser desorption ionizationtime of flight mass spectrometry. We used logistic regression models considering different genetic inheritance models to assess the association of the SNPs with the prevalence of CKD, adjusting for known risk factors. Eight SNPs (rs1126616, rs35068180, rs2238135, rs1800247, rs385564, rs4236, rs2248359, and rs1564858) were associated with CKD even after adjusting by sex, age and race. A model containing five of these SNPs (rs1126616, rs35068180, rs1800247, rs4236, and rs2248359), diabetes and hypertension showed better performance than models considering only clinical risk factors, significantly increasing the area under the curve of the model without polymorphisms. Furthermore, one of the SNPs (the rs2248359) showed an interaction with hypertension, being the risk genotype affecting only hypertensive patients. We conclude that 5 SNPs related to proteins implicated in mineral metabolism disturbances (Osteopontin, osteocalcin, matrix gla protein, matrix metalloprotease 3 and 24 hydroxylase) are associated to an increased risk of suffering CKD

    Trade Wind Boundary Layer Turbulence and Shallow Precipitating Convection: New Insights Combining SAR Images, Satellite Brightness Temperature and Airborne In Situ Measurements

    No full text
    The imprint of marine atmospheric boundary layer (MABL) dynamical structures on sea surface roughness, as seen from Sentinel-1 Synthetic Aperture Radar (SAR) acquisitions, is investigated. We focus on February 13th, 2020, a case study of the EUREC4A (Elucidating the role of clouds-circulation coupling in climate) field campaign. For suppressed conditions, convective rolls imprint on sea surface roughness is confirmed through the intercomparison with MABL turbulent organization deduced from airborne measurements. A discretization of the SAR wide swath into 25 x 25 km2 tiles then allows us to capture the spatial variability of the turbulence organization varying from rolls to cells. Secondly, we objectively detect cold pools within the SAR image and combine them with geostationary brightness temperature. The geometrical or physically-based metrics of cold pools are correlated to cloud properties. This provides a promising methodology to analyze the dynamics of convective systems as seen from below and above. Key Points Atmospheric coherent structures, rolls and cold pools are systematically detected and analyzed in a high-resolution SAR wide swath image Properties of rolls from SAR measurements are comparable with the circulation organization deduced from airborne data A diversity of cold pool geometrical and dynamical features is related to cloud life cycle provided by satellite brightness temperature Plain Language Summary We propose an innovative approach to investigate the marine atmospheric boundary layer dynamics by combining spaceborne Synthetic Aperture Radar (SAR) images, brightness temperature from the Geostationary Operational Environmental Satellite (GOES) and in situ turbulence airborne measurements. Focusing on February 13th, 2020, two types of atmospheric processes are investigated: trade wind boundary layer organizations and cold pools. The signature of coherent structures on sea surface roughness, especially convective rolls, is validated with respect to the turbulence airborne measurements. The cold pools are detected within the SAR image using an identification technique based on the filtering of backscatter signal increments. Cold pool characteristics such as their size or the gust front intensity can then be directly derived from the SAR image. The GOES images provide cloud field properties every 10 min. Exploring backward cloud evolution with respect to the SAR image timing appears able to catch the life cycle of cold pools and convective clouds from which they originate. The application of this approach could pave the way to access the dynamics of convective systems as seen from below and above, allowing to go one step further in the quantitative use of SAR images to investigate boundary layer processes

    First detection of Leishmania infantum DNA within the brain of naturally infected dogs

    No full text
    Visceral leishmaniasis is an anthropozoonosis caused by the protozoan Leishmania infantum (L. chagasi). In dogs, the disease presents with systemic manifestations, including neurological disorders. There are rare reports of the presence of the parasite in the central nervous system of infected dogs, and some evidences of inflammatory lesions and the breakdown of cerebral barriers have been described. The aim of this study was to investigate the presence of L infantum DNA in five specific areas of the brains of 20 naturally infected dogs by real-time PCR. For the first time, the presence of parasite DNA was detected and quantified in the brains of naturally infected dogs, in all evaluated regions. These data provide strong evidence of the presence of the Leishmania parasite in the nervous milieu and contribute to a new perspective of the pathogenesis of visceral leishmaniasis. (C) 2014 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Impaired immune response mediated by prostaglandin E2 promotes severe COVID-19 disease

    No full text
    The SARS-CoV-2 coronavirus has led to a pandemic with millions of people affected. The present study finds that risk-factors for severe COVID-19 disease courses, i.e. male sex, older age and sedentary life style are associated with higher prostaglandin E2 (PGE2) serum levels in blood samples from unaffected subjects. In COVID-19 patients, PGE2 blood levels are markedly elevated and correlate positively with disease severity. SARS-CoV-2 induces PGE2 generation and secretion in infected lung epithelial cells by upregulating cyclo-oxygenase (COX)-2 and reducing the PG-degrading enzyme 15-hydroxyprostaglan- din-dehydrogenase. Also living human precision cut lung slices (PCLS) infected with SARS- CoV-2 display upregulated COX-2. Regular exercise in aged individuals lowers PGE2 serum levels, which leads to increased Paired-Box-Protein-Pax-5 (PAX5) expression, a master regulator of B-cell survival, proliferation and differentiation also towards long lived memory B-cells, in human pre-B-cell lines. Moreover, PGE2 levels in serum of COVID-19 patients lowers the expression of PAX5 in human pre-B-cell lines. The PGE2 inhibitor Taxi- folin reduces SARS-CoV-2-induced PGE2 production. In conclusion, SARS-CoV-2, male sex, old age, and sedentary life style increase PGE2 levels, which may reduce the early anti-viral defense as well as the development of immunity promoting severe disease courses and multiple infections. Regular exercise and Taxifolin treatment may reduce these risks and prevent severe disease courses

    Moderate to Severe Psoriasis in Pediatric and Young Patients: The BIOBADADERM Registry Experience

    No full text
    Childhood-onset psoriasis generally follows an indolent course but patients with moderate or severe disease may require systemic treatment. The aim of this study was to determine the relative proportion of children and young people aged up to 21 years with moderate to severe psoriasis in the BIOBADADERM registry and to analyze the characteristics of these patients, treatments used, and adverse events. Of the 3946 patients in the registry, 24 were aged 21 years or younger. The mean age of this group when they started treatment upon registration on Biobadaderm was 16.1 years and the mean Psoriasis Area and Severity Index was 9.4. In 67% the first treatment recorded was with a conventional systemic drug. Treatment was discontinued in 14 patients (58%) due to adverse events or a loss or lack of effectiveness. In conclusion, the BIOBADADERM registry shows that young people account for a small proportion of psoriasis patients receiving systemic treatment, and they are more likely to be treated using conventional systemic drugs. (C) 2021 AEDV. Published by Elsevier Espana, S.L.U
    corecore