RCAAP - Repositório Científico de Acesso Aberto de Portugal
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Evolutionary timescale of the pulsating white dwarf G117-B15A : the most stable optical clock known
No full textWe observe G117-B15A, the most precise optical clock known, to measure the rate of change of the main pulsation period of this blue-edge DAV white dwarf. Even though the obtained value is only within 1 σ, P = (2.3±1.4) x 10 -15 s s-ˡ, it is already constraining the evolutionary timescale of this cooling white dwarf star
Integrated UBV photometry of 624 star clusters and associations in the Large Magellanic Cloud
No full textWe present a catalogof integrated UBV photometry of 504 star clusters and 120 stellar associations in the LMC, part ofthem still embedded in emitting gas. We study age groups in terms of equivalent SWB types derived from the (U-B) X (B-V) diagram. The size ofthe spatia1 distributions increases steadily with age (SWB types), whereas a difference of axial ratio exists between the groups younger than 30 Myr and those older, which implies a nearly face-on orientation for the former and a tilt of ~45º for the latter groups. Asymmetries are present in the spâtial distributions, which, together with the noncoincidence ofthe centroids for different age groups, suggest that the LMC disk was severely perturbed in the past
Bienestar personal de padres e hijos y sus valores aspirados
No full textO bem-estar pessoal de adolescentes é um tema de crescente interesse na literatura científica, especialmente quando se considera a escassez de artigos que considerem o ponto de vista dos adolescentes. Este estudo busca analisar relações entre bem-estar pessoal de pais e filhos e seus valores aspirados. A amostra compõe-se de 543 adolescentes de 12 a 16 anos, de ambos os sexos, e seus pais ou responsáveis. Utilizam-se os instrumentos Personal Well-Being Index (PWI) para medir níveis de bem-estar, e Aspiration Index para identificar valores aspirados. Obteve-se uma função discriminante entre pais e filhos agrupando significativamente as variáveis de bemestar pessoal discriminando a favor dos filhos, e as variáveis de valores de caráter abstrato e humanista discriminando a favor dos pais, sem apresentar diferenças entre os de valores materiais e de habilidades e conhecimentos. Os resultados contribuem para a discussão sobre a transmissão de valores e do bem-estar em contexto familiar.The personal well-being of adolescents is a subject of growing interest in the scientific literature, especially considering the scarcity of articles that consider adolescent’s points of view. This study aims to analyze the relationships between personal well-being of parents and children and their aspirated values. The sample consists of 543 adolescents aged 12 to 16 years, of both sexes, and their parents or guardians. The Personal Well-Being Index (PWI) is used to measure personal well-being, while the Aspiration Index is used to measure aspired values of both groups. A discriminant function was obtained between parents and children gathering the personal wellbeing variables significantly towards children, and gathering the variables of humanistic values discriminate in favor of parents, without differentiating material values, skill and knowledge’s values. These results contribute to the discussion on the transmission of values and well-being in the family context.El bienestar personal de los adolescentes constituye un tema de creciente interés en la literatura científica, sobre todo cuando se tiene en cuenta el reducido número de artículos que tiene consideran el punto de vista de los adolescentes. Este estudio busca analizar relaciones entre el bienestar personal de padres y hijos y sus valores aspirados. La muestra se compone de 543 adolescentes escolarizados de ambos sexos, con edades comprendidas entre 12 y 16 años y sus padres de ambos sexos entre 27 y 70 años. Se utiliza la escala de Personal Well-Being Index (PWI) para medir los niveles de bienestar, y el Aspiration Index para identificar los valores aspirados por ambos grupos. Se obtuvo una función discriminante entre padres e hijos reuniendo significativamente las variables de bienestar personal a favor de los hijos y las variables de valores de carácter abstracto y humanista a favor de los padres, sin diferenciar los valores materiales, las habilidades y el conocimiento. Los resultados contribuyen a la discusión sobre la transmisión de valores y el bienestar en el contexto familiar
New infrared star clusters in the southern Milky Way with 2MASS
No full textWe carried out a 2MASS J, H and Ks survey of infrared star clusters in the Milky Way sector 230º < l < 350º . This zone was the least studied in the literature, previously including only 12 infrared clusters or stellar groups with |b| < 10º , according to the recent catalogue by Bica et al. (2003).We concentrated e orts on embedded clusters, which are those expected in the areas of known radio and optical nebulae. The present study provides 179 new infrared clusters and stellar groups, which are interesting targets for detailed future infrared studies. The sample of catalogued infrared clusters and stellar groups in the Galaxy is now increased by 63%
Unconventional superconducting granularity of the Y/sub 1-x/Pr/sub x/Ba/sub 2/Cu/sub 3/O/sub 7-[delta]/ compound
No full textWe report on fluctuation magnetoconductivity and magnetic irreversibility of Y1−xPrxBa2Cu3O7− single crystals and a polycrystalline sample. Although our samples are all single phase orthorhombic and the single crystals show no sign of structural inhomogeneity, all the samples exhibit two close and sharp genuine superconducting transitions. On the other hand, while the resistive transition of the polycrystalline sample exhibits in addition a coherence transition characteristic of a granular superconductor and the magnetic irreversibility displays the signature of the intergrain flux dynamics, the single crystals show no sign of these features. In view of these facts, we conclude that the well characterized split superconducting transition must result from a peculiar phase separation related with oxygen doping
Pulmonary tuberculosis and lung cancer : simultaneous and sequential occurrence
No full textObjetivo: O câncer de pulmão (CP) é o tipo mais letal de câncer na população mundial e representa um importante problema de saúde pública. A tuberculose é outra causa significativa de morbidade e mortalidade, especialmente em países em desenvolvimento. A ocorrência de tuberculose pulmonar e CP no mesmo paciente, simultaneamente ou não, tem sido descrita em diversas séries de casos e estudos de caso-controle. O objetivo deste estudo foi descrever as características de pacientes com tuberculose e CP, com apresentação simultânea ou sequencial. Métodos: Estudo transversal, realizado através de revisão de prontuários. Resultados: Foram incluídos no estudo 24 pacientes com diagnósticos de tuberculose e CP no período entre 2009 e 2012. Os diagnósticos de tuberculose e CP ocorreram simultaneamente em 10 pacientes, enquanto a tuberculose foi diagnosticada antes do CP em 14. A mediana do tempo entre os diagnósticos foi de 5 anos (variação interquartil: 1-30 anos). Quatorze pacientes (58,3%) eram do sexo masculino, 20 (83,3%) eram brancos, e 22 (91,7%) eram tabagistas ativos ou ex-tabagistas. O tipo histológico mais comum foi o adenocarcinoma, em 14 casos (58,3%), seguido de carcinoma epidermoide, em 6 (25,0%). Sete pacientes (29,2%) já apresentavam metástases à distância no momento do diagnóstico; desses 7, 5 (71%) tiveram o diagnóstico de CP e TB simultaneamente. Conclusões: Neste estudo, a maioria dos pacientes com tuberculose e CP eram tabagistas ou ex-fumantes e a tuberculose foi diagnosticada tanto antes quanto simultaneamente ao diagnóstico de CP. O carcinoma brônquico não pequenas células, em especial o adenocarcinoma, foi o tipo histológico mais comum.Objective: Lung cancer (LC) is the leading cause of cancer-related death and represents a major public health problem worldwide. Another major cause of morbidity and mortality, especially in developing countries, is tuberculosis. The simultaneous or sequential occurrence of pulmonary tuberculosis and LC in the same patient has been reported in various case series and case-control studies. The objective of this study was to describe the characteristics of patients developing tuberculosis and LC, either simultaneously or sequentially. Methods: This was a cross-sectional study based on the review of medical charts. Results: The study involved 24 patients diagnosed with tuberculosis and LC between 2009 and 2012. The diagnoses of tuberculosis and LC occurred simultaneously in 10 patients, whereas tuberculosis was diagnosed prior to LC in 14. The median time between the two diagnoses was 5 years (interquartile range: 1-30 years). Fourteen patients (58.3%) were male, 20 (83.3%) were White, and 22 (91.7%) were smokers or former smokers. The most common histological type was adenocarcinoma, identified in 14 cases (58.3%), followed by epidermoid carcinoma, identified in 6 (25.0%). Seven patients (29.2%) presented with distant metastases at diagnosis; of those 7 patients, 5 (71%) were diagnosed with LC and tuberculosis simultaneously. Conclusions: In the present study, most of the patients with tuberculosis and LC were smokers or former smokers, and tuberculosis was diagnosed either before or simultaneously with LC. Non-small cell lung cancer, especially adenocarcinoma, was the most common histological type
Photometric variability in a warm, strongly magnetic DQ white dwarf, SDSS J103655.39+652252.2
No full textWe present the discovery of photometric variability in the DQ white dwarf SDSS J103655.39+652252.2 (SDSS J1036+6522). Time-series photometry reveals a coherent monoperiodic modulation at a period of 1115.64751(67) s with an amplitude 0.442% ± 0.024%; no other periodic modulations are observed with amplitudes >~0.13%. The period, amplitude, and phase of this modulation are constant within errors over 16 months. The spectrum of SDSS J1036+6522 shows magnetic splitting of carbon lines, and we use Paschen–Back formalism to develop a grid of model atmospheres for mixed carbon and helium atmospheres. Our models, while reliant on several simplistic assumptions, nevertheless match the major spectral and photometric properties of the star with a self-consistent set of parameters: Teff ≈ 15,500 K, log g ≈ 9, log(C/He) = −1.0, and a mean magnetic field strength of 3.0 ± 0.2 MG. The temperature and abundances strongly suggest that SDSS J1036+6522 is a transition object between the hot, carbon-dominated DQs and the cool, heliumdominated DQs. The variability of SDSS J1036+6522 has characteristics similar to those of the variable hot carbon-atmosphere white dwarfs (DQVs), however, its temperature is significantly cooler. The pulse profile of SDSS J1036+6522 is nearly sinusoidal, in contrast with the significantly asymmetric pulse shapes of the known magnetic DQVs. If the variability in SDSS J1036+6522 is due to the same mechanism as other DQVs, then the pulse shape is not a definitive diagnostic on the absence of a strong magnetic field in DQVs. It remains unclear whether the root cause of the variability in SDSS J1036+6522 and the other hot DQVs is the same
Lattice site investigation of F in preamorphized Si
No full textThe lattice location of F atoms in Si was experimentally studied. Si single crystals were amorphized, implanted with F, and afterwards the amorphous layer was recrystallized. Some of the samples prepared in this way were also annealed at 750 °C for 60 min. The 19F (p, α ƴ)16 resonant nuclear reaction at 340.5 keV was employed to measure the probability of a close encounter between protons and F nuclei as a function of the incident angle with respect to six major crystalline directions. The predictions of several ab initio calculations proved to be incompatible with the present experimental findings
Magnetism in dilute magnetic oxide thin films based on SnO/sub 2/
No full textThin films of SnO2 prepared by pulsed-laser deposition on R-cut sapphire substrates exhibit ferromagnetic properties at room temperature when they are doped with Cr, Mn, Fe, Co, or Ni, but not with other 3d cations. Extrapolated Curie temperatures are generally in excess of 500 K. The moment of the films is roughly independent of doping level, from 0.1–15 at. %, with a value per unit substrate area of 200±100u B nm−2. When magnetization is expressed as a moment per 3d dopant ion, it varies from more than the spin-only value at low concentrations to less than 0.2u B/ion near the percolation threshold. Greatest values are found for iron. The magnetization of the films is highly anisotropic with values when the field is applied perpendicular to the substrate more than double the in-plane values. There is little hysteresis except at high doping levels. The oxides are degenerate n-type semiconductors with a Hall mobility of 100 cm2 V−1 s−1 and 1.4 1019 carriers cm−3 in a one-band model, but no anomalous Hall effect or magnetoresistance was observed at room temperature. The data are discussed in relation to (a) the donor impurity-band model of ferromagnetism in semiconductors and (b) the magnetic defect model
Anchoring the distence scale via x-ray/infrared data for Cepheid clusters : SU Cas
No full textNew X-ray (XMM-Newton) and JHKs (Observatoire du Mont-Mégantic) observations for members of the star cluster Alessi 95, which Turner et al. discovered hosts the classical Cepheid SU Cas, were used in tandem with UCAC3 (proper motion) and Two Micron All Sky Survey observations to determine precise cluster parameters: E(J −H) = 0.08±0.02 and d = 405±15 pc. The ensuing consensus among cluster, pulsation, and trigonometric distances (d = 414±5(σ¯x )±10(σ) pc) places SU Cas in a select group of nearby fundamental Cepheid calibrators (δ Cep, ζ Gem). High-resolution X-ray observations may be employed to expand that sample as the data proved pertinent for identifying numerous stars associated with SU Cas. Acquiring X-ray observations of additional fields may foster efforts to refine Cepheid calibrations used to constrain H0