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

Improving the Knowledge on Seismogenic Sources in the Lower Tagus Valley for Seismic Hazard Purposes

The Lower Tagus Valley, that includes the metropolitan area of Lisbon, has been struck by several earthquakes which produced significant material damage and loss of lives. Their exact location remains unknown. Our goal is to shed some light into the seismogenic sources in the area using seismic reflection and geological data. In areas with no seismic coverage, potential-field data interpretation was carried out. Seismicity was overlaid to the potential seismogenic structures and high-resolution data was acquired in order to confirm which structures have been active into the Quaternary. Three major fault-zones affecting the Neogene were identified: V. F. Xira, Samora-Alcochete and Pinhal Novo. For the first fault, strong evidences suggest it is active. The other two fault-zones and other structures previously unknown can be correlated with several epicentres. Empirical relationships between maximum moment magnitude and fault area indicate that MW > 6.5 earthquakes can be expected for the larger structures

Pair creation of higher dimensional black holes on a de Sitter background

We study in detail the quantum process in which a pair of black holes is created in a higher D-dimensional de Sitter (dS) background. The energy to materialize and accelerate the pair comes from the positive cosmological constant. The instantons that describe the process are obtained from the Tangherlini black hole solutions. Our pair creation rates reduce to the pair creation rate for Reissner-Nordstrom-dS solutions when D=4. Pair creation of black holes in the dS background becomes less suppressed when the dimension of the spacetime increases. The dS space is the only background in which we can discuss analytically the pair creation process of higher dimensional black holes, since the C-metric and the Ernst solutions, that describe respectively a pair accelerated by a string and by an electromagnetic field, are not know yet in a higher dimensional spacetime.Comment: 10 pages; 1 figure included; RexTeX4. v2: References added. Published version. v3: Typo in equation (46) fixe

Teratoma Sacrococcígeo:Caso Clínico

O teratoma sacrococcígeo, embora raro, é a neoplasia mais frequentemente diagnosticada no período neonatal. O diagnóstico é geralmente estabelecido após o nascimento, apesar do uso da ultrassonografia obstétrica permitir um número crescente de sinalizações pré -natais. O principal diagnóstico diferencial é o mielomeningocelo. A monitorização de marcadores tumorais sugestivos da presença de células malignas de um tumor do saco vitelino associado, tal como a alfa- -fetoproteína, e a ressecção precoce do tumor são recomendáveis. Apresenta -se o caso clínico de um recém -nascido do sexo feminino a quem foi detectado ao nascimento uma massa sacrococcígea. A ressonância magnética nuclear admitiu tratar -se de um teratoma sacrococcígeo e o valor de alfa -fetoproteína era normal para a idade da doente. Foi realizada ressecção total do tumor com remoção do cóccix e confi rmado o diagnóstico em estudo anátomo -patológico. A reavaliação posterior da criança revelou um valor decrescente da alfa -fetoproteína, ausência de défi ces motores e um bom aspecto cosmético. A apresentação deste caso clínico pretende realçar a importância do diagnóstico precoce, fundamental para a abordagem terapêutica adequada e melhor prognóstico

Impact of the Nanoscale Organization of Nitroxyl Mixed Self-Assembled Monolayers on their Electrocatalytic Behaviour

Electrocatalysis: The molecular distribution of redox centers on mixed nitroxyl SAMs strongly influences the electrocatalytic reactivity

Effect of Polymer Hydration on the Kinetic Release of Drugs: A Study of Ibuprofen and Ketoprofen in HPMC Matrices

Samples of drug/hydroxypropylmethylcellulose (HPMC) mixtures and matrices (drug/HPMC mixtures plus excipients) were allowed to equilibrate in closed chambers with defined relative humidities (RHs). Their water uptake and drug release were evaluated by differential scanning calorimetry/thermogravimetric analysis and dissolution studies, respectively. Analysis of the thermal behaviors of the drug/HPMC mixtures and of the polymer alone, as functions of RH, leads to the conclusion that most of the hydration water is retained by the polymer, and points to the occurrence of different types of hydration water, from the strongly polymer-bound water molecules at RH values up to 81%, to the almost “free water” for RH values close to 100%. In addition, application of the Korsmeyer model to the dissolution results leads to the conclusion that the rate determining dissolution processes are predominantly of the fickian type.http://www.informaworld.com/10.1081/DDC-12001820

A Simple Realization of the Inverse Seesaw Mechanism

Differently from the canonical seesaw mechanism, which is grounded in grand unified theories, the inverse seesaw mechanism lacks a special framework that realizes it naturally. In this work we advocate that the 3-3-1 model with right-handed neutrinos has such an appropriate framework to accommodate the inverse seesaw mechanism. We also provide an explanation for the smallness of the $\mu$ parameter and estimate the branching ratio for the rare lepton flavor violation process $\mu \rightarrow e\gamma$.Comment: About 14pages, no figures, basis corrected, to appear at the PR

Understanding the design rules for a nonintrusive, textile, heart rate monitoring system

Background and Objectives: Nonintrusive heart rate (HR) monitoring can be a useful tool for health monitoring. By creating capacitively coupled textile electrodes, a comfortable monitoring system can be integrated into seating or bedding that can monitor HR through clothing. This work empirically studied two factors for a system of this type: the electrode size and the material worn by the subject. Materials and Methods: HR measurements were taken using six different sizes of the rectangular textile electrode with four subjects and the signal-to-noise ratio (SNR) of the signals were analyzed. A further set of experiments were conducted with a single subject and a fixed electrode size where different materials were worn. Results: Electrode size was seen to have a statistically insignificant effect on the collected signal quality. The SNR was also largely unaffected by the worn material type. Conclusion: This study provided empirical data relating to two important factors for nonintrusive, textile, and HR monitoring systems. This data will be helpful for designing a seat-based HR monitoring system or to understand the operational limitations of a system of this type

Pulse-height-spectrum distortion in xenon gaseous detectors for soft X-rays: experimental results

The results of an experimental determination of the pulse-height distortion in soft X-ray spectra in gaseous xenon detectors are presented. The study confirms previous Monte Carlo simulation results and emphasizes the importance of the electric field in the drift region in reducing spectral degradation while the effect of a strong magnetic field in the same region is shown to be negligibleJNICT (Junta Nacional de Investigação Científica e Tecnológica) Projecto STRDA/P/CEN/422/9