Influence of Lorentz-violating terms on a two-level system

The influence of Lorentz- and CPT-violating terms of the extended Standard Model on a semi-classical two-level system is analyzed. It is shown that the Lorentz-violating background (when coupled with the fermion sector in a vector way) is able to induce modifications on the Rabi oscillation pattern, promoting sensitive modulations on the usual oscillations. As for the term involving the coefficient coupled in an axial vector way, it brings about oscillations both on energy states and on the spin states (implied by the background). It is also seen that such backgrounds are able to yield state oscillations even in the absence of the electromagnetic field. The foreseen effects are used to establish upper bounds on the Lorentz-violating coefficients.Comment: 13 pages, 6 figures, revtex style

Benefits and Success Factors of Web Services Adoption: An Exploratory Action-research Project in a Brazilian Small Software House

It is usually difficult for companies to keep up with the development of new information technologies and adapt in face of the opportunities and threats those advances may represent. This is especially true for small and medium enterprises (SME) in emerging economies, where resources tend to be scarce and markets more volatile. This paper describes an action-research conducted in a small Brazilian software house that adopted an open-source Web Services development platform in order to improve its software development process. Data analysis revealed critical success factors (CSF) in the adoption process, as well as specific benefits and barriers prone to be faced by small software houses in their adoption efforts. In the process of overcoming such barriers, SME may acquire intellectual capital that represents an essential resource to ensure their competitiveness and survival in emerging economies

Semi-empirical analysis of Sloan Digital Sky Survey galaxies: II. The bimodality of the galaxy population revisited

We revisit the bimodal distribution of the galaxy population commonly seen in the local universe. Here we address the bimodality observed in galaxy properties in terms of spectral synthesis products, such as mean stellar ages and stellar masses, derived from the application of this powerful method to a volume-limited sample, with magnitude limit cutoff M_r = -20.5, containing about 50 thousand luminous galaxies from the SDSS Data Release 2. In addition, galaxies are classified according to their emission line properties in three distinct spectral classes: star-forming galaxies, with young stellar populations; passive galaxies, dominated by old stellar populations; and, hosts of active nuclei, which comprise a mix of young and old stellar populations. We show that the extremes of the distribution of some galaxy properties, essentially galaxy colours, 4000 A break index, and mean stellar ages, are associated to star-forming galaxies at one side, and passive galaxies at another. We find that the mean light-weighted stellar age of galaxies is the direct responsible for the bimodality seen in the galaxy population. The stellar mass, in this view, has an additional role since most of the star-forming galaxies present in the local universe are low-mass galaxies. Our results also give support to the existence of a 'downsizing' in galaxy formation, where massive galaxies seen nowadays have stellar populations formed at early times.Comment: 18 pages, 19 figures, accepted for publication in MNRA

Missing data in trial-based cost-effectiveness analysis: An incomplete journey

Cost-effectiveness analyses (CEA) conducted alongside randomised trials provide key evidence for informing healthcare decision making, but missing data pose substantive challenges. Recently, there have been a number of developments in methods and guidelines addressing missing data in trials. However, it is unclear whether these developments have permeated CEA practice. This paper critically reviews the extent of and methods used to address missing data in recently published trial-based CEA. Issues of the Health Technology Assessment journal from 2013 to 2015 were searched. Fifty-two eligible studies were identified. Missing data were very common; the median proportion of trial participants with complete cost-effectiveness data was 63% (interquartile range: 47%-81%). The most common approach for the primary analysis was to restrict analysis to those with complete data (43%), followed by multiple imputation (30%). Half of the studies conducted some sort of sensitivity analyses, but only 2 (4%) considered possible departures from the missing-at-random assumption. Further improvements are needed to address missing data in cost-effectiveness analyses conducted alongside randomised trials. These should focus on limiting the extent of missing data, choosing an appropriate method for the primary analysis that is valid under contextually plausible assumptions, and conducting sensitivity analyses to departures from the missing-at-random assumption

Tuberculose pulmonar: relação entre baciloscopia do escarro e lesões radiológicas

OBJECTIVES: To determine the frequency of radiological manifestations of chest tuberculosis among the tuberculosis outpatients at the Santa Casa de Misericórdia de São Paulo Hospital, and to correlate these radiological findings with the sputum bacilloscopy. SAMPLE AND METHODS: A review was made of the medical record cards and chest X-rays of all patients attended between January 1996 and December 1998. Patients with a diagnosis of tuberculosis who presented intrathoracic manifestations of the disease and negative anti-HIV serology were selected. RESULTS: The selection included 153 patients, with an average age of 37.5 years, who were predominantly male (60.8%) and white (56.9%). Pulmonary lesions were present in 121 (79.9%) and extrapulmonary lesions in 32 (20.1%). Parenchymal-infiltrate lesions appeared in 56 patients (36.6%), cavity lesions in 55 (36.0%), pleural effusion in 28 (18.3%), isolated nodules in 6 (3.9%), mediastinal enlargement in 4 (2.6%) and miliary pattern in 4 (2.6%). Cavities were present in 45.5% of the patients with pulmonary lesions, generally in association with the parenchymal-infiltrate lesions. Parenchymal infiltrate was present in 86.8% of the patients with pulmonary lesions. There was significant presence of alcohol-acid resistant bacillus in the sputum of patients with cavities (76.4%), in comparison with those without cavities (50%) (p = 0.003). CONCLUSIONS: Parenchymal-infiltrate lesions are the most frequent radiological manifestation of pulmonary tuberculosis, and they are generally associated with cavities. There is a relationship between the presence of acid fast bacilli in sputum and pulmonary cavity lesions.OBJETIVOS: Determinar a freqüência das manifestações radiológicas da tuberculose nos pacientes do Ambulatório de Tuberculose do Departamento de Medicina da Santa Casa de Misericórdia de São Paulo, e correlacionar a manifestação radiológica e a baciloscopia direta do escarro. CASUÍSTICA E MÉTODOS: Foram revisados os prontuários e as radiografias de tórax de todos os doentes atendidos entre janeiro/1996 e dezembro/1998. Foram selecionados os doentes com diagnóstico de tuberculose e que apresentavam manifestação intratorácica da doença e sorologia anti-HIV negativa. RESULTADOS: Foram incluídos 153 doentes, média de 37,5 anos, predominância do sexo masculino (60,8%) e da raça branca (56,9%). Lesões pulmonares estavam presentes em 121 (79,1%); no restante ocorreu envolvimento torácico sem comprometimento pulmonar. Alterações do tipo infiltrado pulmonar ocorreram em 56 (36,6%), cavidade em 55 (36,0%), derrame pleural em 28 (18,3%), nódulo isolado em 6 (3,9%), linfonodomegalia mediastinal em 4 (2,6%) e padrão miliar em 4 (2,6%). Excetuando-se as lesões extrapulmonares, cavidades estiveram presentes em 45,5% dos doentes com lesões pulmonares. Considerando o infiltrado pulmonar que acompanhou a lesão cavitária, em 105 (68,6%) o infiltrado esteve presente. Excluindo-se aqueles com lesões extrapulmonares, o infiltrado apareceu em 86,8% dos doentes com lesões pulmonares. Baciloscopia foi positiva em 76,4% dos doentes com cavidade e em 50,0% dos sem cavidade (p = 0,003). CONCLUSÕES: O infiltrado pulmonar constitui-se na manifestação radiográfica mais freqüente da tuberculose pulmonar, estando a cavidade geralmente associada às lesões do tipo infiltrado pulmonar. Existe relação entre a presença de BAAR no escarro e as lesões cavitárias pulmonares

Steady State Analysis of an Open Economy General Equilibrium Model for Brazil

The aim of the present research is to build an open economy recursive general equilibrium model for the Brazilian economy in order to numerically assess the corresponding steady state equilibrium. This characterization allows us to numerically compute the endogenously determined steady state key relationship, namely the primary surplus aggregate output as well as the debt-product ratio among other variables, as functions of the monetary and fiscal policy parameters chosen by the government of the model economy. The adopted model introduces a transaction technology, which allows us to obtain a monetary equilibrium at steady state. This economy differs from the one used by Ljungqvist and Sargent (2000) for it considers an open economy with accumulation and production. The main result has shown that under the adopted parameterization the steady state of the model economy can numerically characterized by a debt output ratio of 0.3387. The numerical simulations show alternative steady states attainable by the government of the model economy. In order to finance higher expenses the government is bounded to trade-off higher interest rate (low inflation or high return on real money balances) with low operational surpluses due to the higher debt output ratio at the long run equilibrium.