1,842 research outputs found

    Errors in Estimating Omega_Lambda due to the Fluid Approximation

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    5 pages, 2 figures5 pages, 2 figures5 pages, 2 figuresThe matter content of the Universe is strongly inhomogeneous on small scales. Motivated by this fact, we consider a model of the Universe that has regularly spaced discrete masses, rather than a continuous fluid. The optical properties of such space-times can differ considerably from the continuous fluid case, even if the 'average' dynamics are the same. We show that these differences have consequences for cosmological parameter estimation, and that fitting to recent supernovae observations gives a correction to the inferred value of Omega_Lambda of ~10%

    Toxicidade Pulmonar Aguda Precoce Associada à Amiodarona

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    Amiodarone is a potent anti-arrhythmic drug with a well-known potential chronic pulmonary toxicity. We describe a case of acute pulmonary toxicity (APT) induced by amiodarone in a 57 year old patient submitted to a perfusion of 900 mg in just 6 hours, to control an auricular flutter with rapid ventricular response. During the administration, the patient developed hemodynamic instability and oxygen dessaturation that led to an electrical cardioversion with return of sinus rhythm. Still, the patient continued in progressive respiratory deterioration with acute bilateral infiltrates on chest x-ray and apparent normal cardiac filling pressures confirmed by echocardiography. Anon-cardiogenic pulmonar edema progressing to clinico-physiological ARDS criteria was diagnosed. Expeditive therapeutic measures were undertaken, namely by initiation of non-invasive positive airway pressure support, that attained a good result.Albeit rare, amiodarone-induced APT might have severe consequences, namely progression to ALI/ARDS with a high mortality index.As it is a frequently prescribed drug, there should be a high clinical suspicion towards this phenomenon, allowing precocious therapeutic measures to be taken in a timely fashion to prevent the associated unfavorable outcome

    What the small angle CMB really tells us about the curvature of the Universe

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    5 pages, 3 figures. Corrections made to published version5 pages, 3 figures. Corrections made to published version5 pages, 3 figures. Corrections made to published versionIt is well known that observations of the cosmic microwave background (CMB) are highly sensitive to the spatial curvature of the Universe, k. Here we find that what is in fact being tightly constrained by small angle fluctuations is spatial curvature near the surface of last scattering, and that if we allow k to be a function of position, rather than taking a constant value everywhere, then considerable spatial curvature is permissible within our own locale. This result is of interest for the giant void models that attempt to explain the supernovae observations without Dark Energy. We find voids models with a homogeneous big bang can be compatible with the observed small angle CMB, but only if they exist in a positively curved universe. To be compatible with local measurements of H_0, however, we find that a radially varying bang time is required

    Characterization of Myeloid Cellular Populations in Mesenteric and Subcutaneous Adipose Tissue of Holstein-Friesian Cows

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    Immune cells resident in adipose tissue have important functions in local and systemic metabolic homeostasis. Nevertheless, these immune cell populations remain poorly characterized in bovines. Recently, we described diverse lymphocyte subpopulations in adipose tissue of Holstein-Friesian cows. Here, we aimed at characterising myeloid cell populations present in bovine adipose tissue using multicolour flow cytometry, cell sorting and histochemistry/immunohistochemistry. Macrophages, CD14(+)CD11b(+)MHC-II(+)CD45(+) cells, were identified in mesenteric and subcutaneous adipose tissue, though at higher proportions in the latter. Mast cells, identified as SSC-A(high)CD11b(-/+)CD14(-)MHC-II(-)CH138A(-)CD45(+) cells, were also observed in adipose tissue and found at higher proportions than macrophages in mesenteric adipose tissue. Neutrophils, presenting a CH138A(+)CD11b(+) phenotype, were also detected in mesenteric and subcutaneous adipose tissue, however, at much lower frequencies than in the blood. Our gating strategy allowed identification of eosinophils in blood but not in adipose tissue although being detected by morphological analysis at low frequencies in some animals. A population not expressing CD45 and with the CH138A(+) CD11b(-)MHC-II- phenotype, was found abundant and present at higher proportions in mesenteric than subcutaneous adipose tissue. The work reported here may be useful for further studies addressing the function of the described cells

    Viral, host and environmental factors that favor anthropozoonotic spillover of coronaviruses: An opinionated review, focusing on SARS-CoV, MERS-CoV and SARS-CoV-2

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    Environmental factors play a key role in the zoonotic transmission of emerging pathogenic viruses as mankind is constantly disturbing wildlife's ecosystems usually by cutting down forests to build human settlements or by catching wild animals for food, which deprives the viruses of their natural hosts and gives them opportunity to infect humans. In December 2019, a new coronavirus emerged from bats and was named SARS-CoV-2 by the International Committee for Taxonomy of Viruses, and the disease it causes named COVID-19 by the World Health Organization. Disease outbreaks such as SARS in 2002–2003, MERS in 2012 and the current COVID-19 pandemic are the result of higher mutation rates of coronaviruses and their unique capacity for genetic recombination, resulting in adaptations that make them more suitable to cross the species barriers and infect other species. This ability for host switching and interspecies infection is often attributed to the great diversity of these viruses, which is a result of viral and host factors such as the low fidelity of their RNA-dependent RNA polymerase, the high frequency of their homologous RNA recombination, and the adaptation of the S protein to bind host receptors like the angiotensin converting enzyme 2 (ACE2) in the case of SARS-CoV and SARS-CoV-2, and dipeptidyl peptidase 4 (DDP4) in MERS-CoV. This review presents an overview of the zoonotic transmission of SARS, MERS and COVID-19, focusing on the viral, host and environmental factors that favor the spillover of these viruses into humans, as well as the biological and ecological factors that make bats the perfect animal reservoir of infection for these viruses.This work was financially supported by the RESEARCH4COVID program under the projects SARSBLOODsafe (ref 021), Cdots Biosensing COVID19 (ref 041) and fta4COVID19 (ref 598) funded by the Portuguese Foundation for Science and Technology (FCT); Priscilla Gomes da Silva thanks FCT for the financial support of her PhD work contract through the DOCTORATES 4 COVID-19 program

    Modulation of Leptin and Leptin Receptor Expression in Mice Acutely Infected with Neospora caninum

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    Neospora caninumis an apicomplexan parasite that in cattle assumes particular importance, as it is responsible for abortions reported worldwide. Leptin is an adipokine mainly secreted by adipocytes, which beside its role in maintaining metabolic homeostasis also has important effects in both innate and adaptive immunity. In previous work, we showed that mice chronically infected withN. caninumhad elevated serum leptin levels. Here, we sought to assess whether acute infection withN. caninuminfection influenced the production of this adipokine as well as leptin receptor mRNA levels. Our results show that acute infection withN. caninumled to decreased leptin serum levels and mRNA expression in adipose tissue. A decrease in leptin receptor transcript variant 1 mRNA (long isoform) and leptin receptor transcript variant 3 mRNA (one of the short isoforms) expression was also observed. An increase in the number of cells staining positive for leptin in the liver of infected mice was observed, although this increase was less marked in Interleukin (IL)-12/IL-23 p40-deficient mice. Overall, our results show thatN. caninuminfection also influences leptin production during acute infection

    Reasons for Prosecutorial Decisions

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    In terms of the prosecuting policy of the National Prosecuting Authority reasons for the exercise of prosecutorial discretions should be furnished on request of persons with a legitimate interest in the decisions. In general only the broad reasons should be provided and not the specific particulars of the decision. This approach is based on two important policy considerations. The first is that the decisions of the prosecuting authority should be transparent since it is a requirement for upholding the legality principle. The second is that the furnishing of specific particulars could result in a violation of the rights of individuals, for example it could create doubt about the innocence of a person without him or her ever having been subjected to a criminal trial. This contribution investigates issues such as the nature of the duty to provide reasons for prosecutorial decisions, the identification of the parties that are entitled to the reasons for a particular prosecutorial decision, and the furnishing of reasons in order to enhance the judicial review of prosecutorial decisions.   &nbsp

    The kSZ effect as a test of general radial inhomogeneity in LTB cosmology

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    The apparent accelerating expansion of the Universe, determined from observations of distant supernovae, and often taken to imply the existence of dark energy, may alternatively be explained by the effects of a giant underdense void if we relax the assumption of homogeneity on large scales. Recent studies have made use of the spherically symmetric, radially inhomogeneous Lemaître-Tolman-Bondi (LTB) models to derive strong constraints on this scenario, particularly from observations of the kinematic Sunyaev-Zel’dovich effect which is sensitive to large-scale inhomogeneity. However, most of these previous studies explicitly set the LTB “bang time” function to be constant, neglecting an important freedom of the general solutions. Here we examine these models in full generality by relaxing this assumption. We find that although the extra freedom allowed by varying the bang time is sufficient to account for some observables individually, it is not enough to simultaneously explain the supernovae observations, the small-angle CMB, the local Hubble rate, and the kinematic Sunyaev-Zel’dovich effect. This set of observables is strongly constraining, and effectively rules out simple LTB models as an explanation of dark energy

    Relativistic drag forces on black holes from scalar dark matter clouds of all sizes

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    We use numerical simulations of scalar field dark matter evolving on a moving black hole background to confirm the regime of validity of (semi)analytic expressions derived from first principles for both dynamical friction and momentum accretion in the relativistic regime. We cover both small and large clouds (relative to the de Broglie wavelength of the scalars), and light and heavy particle masses (relative to the black hole size). In the case of a small dark matter cloud, the effect of accretion is a non-negligible contribution to the total force on the black hole, even for small scalar masses. We confirm that this momentum accretion transitions between two regimes (wave and particlelike) and we identify the mass of the scalar at which the transition between regimes occurs
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