9 resultados para CLASSICAL CEPHEIDS

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


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The aim of this work is to derive precise reddenings for 31 Cepheids using multiphase high-resolution spectroscopic observations and literature-derived colors. Each individual reddening value was determined as a difference between the observed (B - V) value and a calculated (B - V) value based on Castelli stellar model atmospheres and atmosphere parameters (effective temperature and gravity) previously determined through high-resolution spectroscopic analysis. This procedure was repeated for all pulsational phases at which spectra were obtained (typically 11 spectra for each star). After that, the mean reddening value for a given Cepheid was obtained. The reddening values derived were compared to values based on the use of distances and multiband photometry, reaching the general conclusion that reddening derived in this manner agrees with those from other methods.

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The parameters for the newly discovered open cluster Alessi 95 are established on the basis of available photometric and spectroscopic data, in conjunction with new observations. Colour excesses for spectroscopically observed B- and A-type stars near SU Cas follow a reddening relation described by E(U-B)/E(B-V) = 0.83 + 0.02E(B-V), implying a value of R=AV/E(B-V) ? 2.8 for the associated dust. Alessi 95 has a mean reddening of E(B-V)(B0) = 0.35 +/- 0.02 s.e., an intrinsic distance modulus of V0-MV= 8.16 +/- 0.04 s.e. (+/- 0.21 s.d.), d= 429 +/- 8 pc, and an estimated age of 108.2 yr from zero-age main sequence (ZAMS) fitting of available UBV, CCD BV, NOMAD, and Two Micron All Sky Survey JHKs observations of cluster stars. SU Cas is a likely cluster member, with an inferred space reddening of E(B-V) = 0.33 +/- 0.02 and a luminosity of < MV >=-3.15 +/- 0.07 s.e., consistent with overtone pulsation (PFM= 2.75 d), as also implied by the Cepheids light-curve parameters, rate of period increase and Hipparcos parallaxes for cluster stars. There is excellent agreement of the distance estimates for SU Cas inferred from cluster ZAMS fitting, its pulsation parallax derived from the infrared surface brightness technique and Hipparcos parallaxes, which all agree to within a few per cent.

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We derive general rigorous lower bounds for the average ground state energy per site e ((d)) of the quantum and classical Edwards-Anderson spin-glass model in dimensions d=2 and d=3 in the thermodynamic limit. For the classical model they imply that e ((2))a parts per thousand yena'3/2 and e ((3))a parts per thousand yena'2.204a <-.

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Background: CAH patients have an increased risk of cardiovascular disease, and it remains unknown if lifelong glucocorticoid (GC) treatment is a contributing factor. In the general population, glucocorticoid receptor gene (NR3C1) polymorphisms are associated with an adverse metabolic profile. Our aim was to analyze the association between the NR3C1 polymorphisms and the metabolic profile of CAH patients. Methodology: Sixty-eight adult patients (34SV/34SW) with a mean age of 28.4 +/- 9 years received dexamethasone (mean 0.27 +/- 0.11 mg/day) to obtain normal androgen levels. SW patients also received fludrocortisone (50 mu g/day). Metabolic syndrome (MetS) was defined by the NCEP ATPIII criteria and obesity by BMI >= 30 kg/m(2). NR3C1 alleles were genotyped, and association analyses with phenotype were carried out with Chi-square, t-test and regression analysis. Results: Obesity and MetS were observed in 23.5% and 7.3% of patients, respectively, and were not correlated with GC doses and treatment duration. BMI was positively correlated with blood pressure (BP), triglycerides (TG), LDL-c levels and HOMA-IR and inversely correlated with HDL-c levels. BclI and A3669G variants were found in 26.4% and 9.6% of alleles, respectively. Heterozygotes for the BclI polymorphism presented with higher BMI (29 kg/m(2) +/- 5.3 vs. 26 kg/m(2) +/- 5.3, respectively) and waist circumference (89 cm +/- 12.7 vs. 81 cm +/- 13, respectively) compared to wild-type subjects. Hypertension was found in 12% of patients and heterozygotes for the BclI polymorphism presented higher systolic BP than wild type subjects. Low HDL-c and high TG levels were identified in 30% and 10% of patients, respectively, and were not associated with the NR3C1 polymorphisms. A3669G carriers and non-carriers did not differ. Conclusion: In addition to GC therapy, the BclI GR variant might play an important role in obesity susceptibility in CAH patients. Genotyping of GR polymorphisms could result in the identification of a subgroup at risk patients, allowing for the establishment of personalized treatment and the avoidance of long-term adverse consequences.

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The non-classical human leukocyte antigen (HLA) class I genes present a very low rate of variation. So far, only 10 HLA-E alleles encoding three proteins have been described, but only two are frequently found in worldwide populations. Because of its historical background, Brazilians are very suitable for population genetic studies. Therefore, 104 bone marrow donors from Brazil were evaluated for HLA-E exons 14. Seven variation sites were found, including two known single nucleotide polymorphisms (SNPs) at positions +424 and +756 and five new SNPs at positions +170 (intron 1), +1294 (intron 3), +1625, +1645 and +1857 (exon 4). Haplotyping analysis did show eight haplotypes, three of them known as E*01:01:01, E*01:03:01 and E*01:03:02:01 and five HLA-E new alleles that carry the new variation sites. The HLA-E*01:01:01 allele was the predominant haplotype (62.50%), followed by E*01:03:02:01 (24.52%). Selective neutrality tests have disclosed an interesting pattern of selective pressures in which balancing selection is probably shaping allele frequency distributions at an SNP at exon 3 (codon 107), sequence diversity at exon 4 and the non-coding regions is facing significant purifying pressure. Even in an admixed population such as the Brazilian one, the HLA-E locus is very conserved, presenting few polymorphic SNPs in the coding region.

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A dimensional analysis of the classical equations related to the dynamics of vector-borne infections is presented. It is provided a formal notation to complete the expressions for the Ross' threshold theorem, the Macdonald's basic reproduction "rate" and sporozoite "rate", Garret-Jones' vectorial capacity and Dietz-Molineaux-Thomas' force of infection. The analysis was intended to provide a formal notation that complete the classical equations proposed by these authors.

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The classical magnetoresistance of a two-dimensional electron gas constrained to non-planar topographies, in antidot lattices, and under the influence of tilted magnetic field in arbitrary direction is numerically studied. (C) 2012 Elsevier B.V. All rights reserved.

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Aspects related to the users' cooperative work are not considered in the traditional approach of software engineering, since the user is viewed independently of his/her workplace environment or group, with the individual model generalized to the study of collective behavior of all users. This work proposes a process for software requirements to address issues involving cooperative work in information systems that provide distributed coordination in the users' actions and the communication among them occurs indirectly through the data entered while using the software. To achieve this goal, this research uses ergonomics, the 3C cooperation model, awareness and software engineering concepts. Action-research is used as a research methodology applied in three cycles during the development of a corporate workflow system in a technological research company. This article discusses the third cycle, which corresponds to the process that deals with the refinement of the cooperative work requirements with the software in actual use in the workplace, where the inclusion of a computer system changes the users' workplace, from the face to face interaction to the interaction mediated by the software. The results showed that the highest degree of users' awareness about their activities and other system users contribute to a decrease in their errors and in the inappropriate use of the system.

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The Josephson junction model is applied to the experimental implementation of classical bifurcation in a quadrupolar nuclear magnetic resonance system. There are two regimes, one linear and one nonlinear, which are implemented by the radio-frequency and the quadrupolar terms of the Hamiltonian of a spin system, respectively. These terms provide an explanation of the symmetry breaking due to bifurcation. Bifurcation depends on the coexistence of both regimes at the same time in different proportions. The experiment is performed on a lyotropic liquid crystal sample of an ordered ensemble of 133Cs nuclei with spin I = 7/2 at room temperature. Our experimental results confirm that bifurcation happens independently of the spin value and of the physical system. With this experimental spin scenario, we confirm that a quadrupolar nuclei system could be described analogously to a symmetric two-mode Bose-Einstein condensate.