1,452 research outputs found
Fitting isochrones to open cluster photometric data III. Estimating metallicities from UBV photometry
The metallicity is a critical parameter that affects the correct
determination fundamental characteristics stellar cluster and has important
implications in Galactic and Stellar evolution research. Fewer than 10 % of the
2174 currently catalog open clusters have their metallicity determined in the
literature. In this work we present a method for estimating the metallicity of
open clusters via non-subjective isochrone fitting using the cross-entropy
global optimization algorithm applied to UBV photometric data. The free
parameters distance, reddening, age, and metallicity simultaneously determined
by the fitting method. The fitting procedure uses weights for the observational
data based on the estimation of membership likelihood for each star, which
considers the observational magnitude limit, the density profile of stars as a
function of radius from the center of the cluster, and the density of stars in
multi-dimensional magnitude space. We present results of [Fe/H] for nine
well-studied open clusters based on 15 distinct UBV data sets. The [Fe/H]
values obtained in the ten cases for which spectroscopic determinations were
available in the literature agree, indicating that our method provides a good
alternative to determining [Fe/H] by using an objective isochrone fitting. Our
results show that the typical precision is about 0.1 dex
Combining type I and type II seesaw mechanisms in the minimal 3-3-1 model
The minimal 3-3-1 model is perturbative until energies around 4-5TeV, posing
a challenge to generate neutrino masses at eV scale, mainly if one aims to take
advantage of the seesaw mechanism. As a means to circumvent this problem we
propose a modification of the model such that it accommodates the type I and
type II seesaw mechanisms altogether. We show that the conjunction of both
mechanisms yield a neutrino mass expression suppressed by a high power of the
cutoff scale, , in its denominator. With such a suppression term we
naturally obtain neutrino masses at eV scale when is around few TeV. We
also investigate the size of lepton flavor violation through the process .Comment: about 15 pages, no figure
Bilateral Shoulder Arthritis in COVID-19 Patient After Prolonged Mechanical Ventilation Assist: a Case Report
Prolonged immobilization and, in particular, mechanical ventilation, have been linked to muscle atrophy. Anecdotal reports in the literature describe rhabdomyolysis as a potential late complication of COVID-19 infection which, in severe cases, may coexist with fluid collections. We report a case of a 28-year-old patient that had been recently hospitalized with SARS-CoV-2 pneumonia, with need for invasive ventilation support. Days after being discharged, the patient presents with retrosternal thoracalgia irradiating to the left upper limb. On physical examination, abduction and external rotation were limited due to pain complaints and there was soft tissue swelling of the corresponding shoulder and arm. Imaging evaluation was essential to establish the underlying condition, revealing bilateral arthritis communicating with large rotator cuff collections, which was considered of septic nature.info:eu-repo/semantics/publishedVersio
Ketogenic Diet and Drug-Induced Hepatotoxicity During Tuberculosis Treatment
When therapy with hepatotoxic drugs is being considered, all other possible contributing agents of liver damage should be held to account. While not generally considered a risk factor, we present 2 cases in which ketogenic diet (KD) may have played a role in liver injury due to antituberculosis drugs. Ketogenic diet has been linked to liver injury, and while its pathophysiology remains obscure, carnitine depletion could play a role, as it is a mechanism of liver damage common to KD and antituberculosis drug regimens.info:eu-repo/semantics/publishedVersio
Low-level laser therapy in neurosensory recovery : case series in dental and maxillofacial rehabilitation
Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio
Bitemarks analysis of orthodontically treated suspects – an identification approach
Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio
JAK2V617F allele burden is associated with thrombotic mechanisms activation in polycythemia vera and essential thrombocythemia patients
The clinical courses of polycythemia vera (PV) and essential thrombocythemia (ET) are characterized by thrombohemorrhagic diathesis. Several groups have suggested an association between JAK2V617F mutation and thrombosis. We hypothesized a relationship between JAK2V617F allele burden, cellular activation parameters, and thrombosis. We evaluated a group of PV and ET patients using flow cytometry: platelet CD62P, CD63, and dense granules, platelet-leukocyte aggregates (PLA), leukocyte CD11b and monocyte tissue factor (TF) expression. All patients had increased baseline platelet CD62P and CD63 expression (p 50 % presented higher levels of leukocyte activation. In ET, thrombosis was associated with JAK2V617F mutation (p < 0.05, χ (2) = 5.2), increased monocyte CD11b (p < 0.05) and with platelet-PMN aggregates (p < 0.05). In ET patients, hydroxyurea does not significantly reduce the activation parameters. Our data demonstrate that JAK2V617F allele burden is directly correlated with activation parameters that drive mechanisms that favor thrombosis.info:eu-repo/semantics/publishedVersio
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