182 research outputs found

    Asteroids' physical models from combined dense and sparse photometry and scaling of the YORP effect by the observed obliquity distribution

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    The larger number of models of asteroid shapes and their rotational states derived by the lightcurve inversion give us better insight into both the nature of individual objects and the whole asteroid population. With a larger statistical sample we can study the physical properties of asteroid populations, such as main-belt asteroids or individual asteroid families, in more detail. Shape models can also be used in combination with other types of observational data (IR, adaptive optics images, stellar occultations), e.g., to determine sizes and thermal properties. We use all available photometric data of asteroids to derive their physical models by the lightcurve inversion method and compare the observed pole latitude distributions of all asteroids with known convex shape models with the simulated pole latitude distributions. We used classical dense photometric lightcurves from several sources and sparse-in-time photometry from the U.S. Naval Observatory in Flagstaff, Catalina Sky Survey, and La Palma surveys (IAU codes 689, 703, 950) in the lightcurve inversion method to determine asteroid convex models and their rotational states. We also extended a simple dynamical model for the spin evolution of asteroids used in our previous paper. We present 119 new asteroid models derived from combined dense and sparse-in-time photometry. We discuss the reliability of asteroid shape models derived only from Catalina Sky Survey data (IAU code 703) and present 20 such models. By using different values for a scaling parameter cYORP (corresponds to the magnitude of the YORP momentum) in the dynamical model for the spin evolution and by comparing synthetics and observed pole-latitude distributions, we were able to constrain the typical values of the cYORP parameter as between 0.05 and 0.6.Comment: Accepted for publication in A&A, January 15, 201

    Neutrino cosmology after DESI: tightest mass upper limits, preference for the normal ordering, and tension with terrestrial observations

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    The recent DESI Baryon Acoustic Oscillation measurements have led to tight upper limits on the neutrino mass sum, potentially in tension with oscillation constraints requiring ∑ mν ≳ 0.06 eV. Under the physically motivated assumption of positive ∑ mν, we study the extent to which these limits are tightened by adding other available cosmological probes, and robustly quantify the preference for the normal mass ordering over the inverted one, as well as the tension between cosmological and terrestrial data. Combining DESI data with Cosmic Microwave Background measurements and several late-time background probes, the tightest 2σ limit we find without including a local H0 prior is ∑ mν < 0.05 eV. This leads to a strong preference for the normal ordering, with Bayes factor relative to the inverted one of 46.5. Depending on the dataset combination and tension metric adopted, we quantify the tension between cosmological and terrestrial observations as ranging between 2.5σ and 5σ. These results are strenghtened when allowing for a time-varying dark energy component with equation of state lying in the physically motivated non-phantom regime, w(z) ≥ -1, highlighting an interesting synergy between the nature of dark energy and laboratory probes of the mass ordering. If these tensions persist and cannot be attributed to systematics, either or both standard neutrino (particle) physics or the underlying cosmological model will have to be questioned

    Fatores Associados ao Baixo Peso ao Nascer em Unidade de Terapia Intensiva Neonatal em um Hospital de Referência

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    Objetivo: Comparar o perfil dos recém-nascidos com baixo peso com os de muito baixo e extremo baixo peso encaminhados para a Unidade de Terapia Intensiva. Métodos: Estudo transversal, retrospectivo com dados de prontuários da maternidade do Hospital Guilherme Álvaro em Santos. Resultados: Não houve associação entre o peso ao nascer com as variáveis maternas: escolaridade, consultas no pré-natal, primigesta, síndrome hipertensiva, restrição de crescimento fetal, idade gestacional e via de parto. Foi maior nos recém-nascidos de muito baixo e extremo baixo peso o tempo de internação, ventilação mecânica invasiva, drogas vasoativas, sepse, nutrição parenteral prolongada e alta sem aleitamento materno exclusivo.  Conclusão: O perfil dos recém-nascidos de baixo peso encaminhados para a Unidade de Terapia Intensiva Neonatal foi, em sua maioria, semelhantes aos encontrados na literatura Recém-nascido de baixo peso; fatores de risco; unidade de terapia intensiva neonatal

    Assessing a measure for Quality of Life in patients with severe Alopecia Areata: a multicentric Italian study

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    objective the prevalence of anxiety and depression in patients diagnosed with alopecia areata (AA) is very high and this significant burden of psychological symptoms threatens the health-related quality of Life (HRQoL) of affected patients. Indeed, AA often does not produce significant physical symptoms, but it nonetheless disrupts many areas of mental health. clinical assessment of disease severity may not reliably predict patient's HRQoL, nor may it predict the patient's perception of illness. for this reason, considerable effort has been made to apply and develop measures that consider patient's perception and assess the HRQoL of individuals affected by AA. the aim of this multicentric study was to provide the Italian version of the Skindex-16AA and to evaluate its psychometric properties in a clinical sample of consecutive patients with moderate-to-severe AA. methods this is a longitudinal, multicenter, observational study. patients returned for follow-up visits at 4-, 12-, and 24-weeks. the analyses of the current work aimed to confirm the factorial structure of the skindex-16AA. in the case of non-fit, an alternative structure for the model was proposed, using an exploratory graph analysis and the bayesian approach. results the sample was composed of 106 patients with AA. alopecia universalis was the most frequently diagnosed type of alopecia at all time points. the analyses on the skindex-16AA revealed that a two-factor structure with eight items fit the data best (bayesian posterior predictive checking using 95% confidence Interval for the difference between the observed and the replicated chi-square values = -6.246/56.395, posterior predictive P-value = 0.06), and reported satisfactory psychometric properties (i.e., internal consistency and convergent validity).conclusion the skindex-8AA demonstrated optimal psychometric properties (i.e., convergent and construct validity, and test-retest reliability) measured in a sample of patients with AA, that may suggest that it is an appropriate tool to measure the HRQoL in AA patients. however, further studies are needed in order to confirm and tested other psychometric features of this tool

    Avian influenza virus isolated in wild waterfowl in Argentina: Evidence of a potentially unique phylogenetic lineage in South America

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    Avian influenza (AI) viruses have been sporadically isolated in South America. The most recent reports are from an outbreak in commercial poultry in Chile in 2002 and its putative ancestor from a wild bird in Bolivia in 2001. Extensive surveillance in wild birds was carried out in Argentina during 2006-2007. Using RRT-PCR, 12 AI positive detections were made from cloacal swabs. One of those positive samples yielded an AI virus isolated from a wild kelp gull (Larus dominicanus) captured in the South Atlantic coastline of Argentina. Further characterization by nucleotide sequencing reveals that it belongs to the H13N9 subtype. Phylogenetic analysis of the 8 viral genes suggests that the 6 internal genes are related to the isolates from Chile and Bolivia. The analysis also indicates that a cluster of phylogenetically related AI viruses from South America may have evolved independently, with minimal gene exchange, from influenza viruses in other latitudes. The data produced from our investigations are valuable contributions to the study of AI viruses in South America.Centro de Estudios Parasitológicos y de Vectore

    Yolk sac macrophage progenitors traffic to the embryo during defined stages of development

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    Tissue macrophages in many adult organs originate from yolk sac (YS) progenitors, which invade the developing embryo and persist by means of local self-renewal. However, the route and characteristics of YS macrophage trafficking during embryogenesis are incompletely understood. Here we show the early migration dynamics of YS-derived macrophage progenitors in vivo using fate mapping and intravital microscopy. From embryonic day 8.5 (E8.5) CX(3)CR1+ pre-macrophages are present in the mouse YS where they rapidly proliferate and gain access to the bloodstream to migrate towards the embryo. Trafficking of pre-macrophages and their progenitors from the YS to tissues peaks around E10.5, dramatically decreases towards E12.5 and is no longer evident from E14.5 onwards. Thus, YS progenitors use the vascular system during a restricted time window of embryogenesis to invade the growing fetus. These findings close an important gap in our understanding of the development of the innate immune system

    Metabolic changes in concussed American football players during the acute and chronic post-injury phases

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    <p>Abstract</p> <p>Background</p> <p>Despite negative neuroimaging findings many athletes display neurophysiological alterations and post-concussion symptoms that may be attributable to neurometabolic alterations.</p> <p>Methods</p> <p>The present study investigated the effects of sports concussion on brain metabolism using <sup>1</sup>H-MR Spectroscopy by comparing a group of 10 non-concussed athletes with a group of 10 concussed athletes of the same age (mean: 22.5 years) and education (mean: 16 years) within both the acute and chronic post-injury phases. All athletes were scanned 1-6 days post-concussion and again 6-months later in a 3T Siemens MRI.</p> <p>Results</p> <p>Concussed athletes demonstrated neurometabolic impairment in prefrontal and motor (M1) cortices in the acute phase where NAA:Cr levels remained depressed relative to controls. There was some recovery observed in the chronic phase where Glu:Cr levels returned to those of control athletes; however, there was a pathological increase of m-I:Cr levels in M1 that was only present in the chronic phase.</p> <p>Conclusions</p> <p>These results confirm cortical neurometabolic changes in the acute post-concussion phase as well as recovery and continued metabolic abnormalities in the chronic phase. The results indicate that complex pathophysiological processes differ depending on the post-injury phase and the neurometabolite in question.</p
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