Simplified quartessence cosmology

We propose a new class of accelerating world models unifying the cosmological dark sector (dark matter and dark energy). All the models are described by a simplified version of the Chaplygin gas quartessence cosmology. It is found that even for Omega(k) not equal 0, this quartessence scenario depends only on a pair of parameters which can severely be constrained by the cosmological tests. As an example we perform a joint analysis involving the latest SNe type la data and the recent Sloan Digital Sky Survey measurement of baryon acoustic oscillations. In our analysis we have considered the SNe type la Union sample compiled by Kowalski et al. [M. Kowalski et al., Astrophys. J. 686 (2008) 749, arXiv:0804.4142]. At 95.4% (c.l.), we find for BAD + Union sample, alpha = 0.81(-0.04)(+0.04) and Omega(Q4) = 1.15(-0.17)(+0.16) The best-fit for this simplified quartessence scenario is a spatially closed Universe and its reduced chi(2) is exactly the same of the flat concordance model (Lambda CDM). (C) 2009 Elsevier B.V. All rights reserved.

Permanence of stability for a class of system of differential equations with two delays

The paper studies a class of a system of linear retarded differential difference equations with several parameters. It presents some sufficient conditions under which no stability changes for an equilibrium point occurs. Application of these results is given. (c) 2007 Elsevier Ltd. All rights reserved.

SPECTRUM OF SCREENING MASSES FOR SU(2) GAUGE THEORY: UNIVERSALITY CLASS

In this work we study the spectrum of the lowest screening masses for Yang-Mills theories on the lattice. We used the SU(2) gauge group in (3 + 1) dmensions. We adopted the multiple exponential method and the so-called ""variational"" method, in order to detect possible excited states. The calculations were done near the critical temperature of the confinement-deconfinement phase transition. We obtained values for the ratios of the screening masses consistent with predictions from universality arguments. A Monte Carlo evolution of the screening masses in the gauge theory confirms the validity of the predictions.

Diagnostics for the Developing World: Microfluidic Paper-Based Analytical Devices

Microfluidic paper-based analytical devices (mu PADs) are a new class of point-of-care diagnostic devices that are inexpensive, easy to use, and designed specifically for use in developing countries. (To listen to a podcast about this feature, please go to the Analytical Chemistry multimedia page at pubs.acs.org/page/ancham/audio/index.html.)

Future cenario planning in Brazilian logistics and transportation sector

Nas últimas décadas o setor de logística passou por grandes transformações pelo mundo. Assim, a eficiência do sistema logístico é importante para o crescimento econômico, a diversificação, redução dos custos operacionais e da pobreza. Segundo o Banco Mundial, o Brasil tornou-se uma das maiores economias do mundo, mas os custos logísticos elevados colocam em risco esse crescimento. Estes custos são em grande parte o resultado de diferenças em infraestrutura de cada região, juntamente com os encargos do setor rodoviário, que corresponde por 60% do total do transporte de carga do país. Entretanto, a logística brasileira está às portas de uma nova revolução, em práticas de negócios e eficiência, e também na qualidade e disponibilidade da infraestrutura de transportes e comunicações, e novos projetos e práticas para superar a situação. O objetivo deste estudo não é analisar o presente e as atuais tendências de logística do Brasil e do setor de transporte, mas sim modelar possíveis cenários futuros para os próximos anos. Em outras palavras, este trabalho mostra diferentes possibilidades de como o setor de logística e transporte poderá ser no futuro. Para isso, este trabalho irá utilizar a metodologia de cenários prospectivos e entrevistas com especialistas relacionados da área.

The Brazilian class C women perception regarding premium mass products in the beauty industry

Recentemente, os mercados emergentes se tornaram um alvo potencial para a indústria da beleza e o Brasil está se tornando um mercado lucrativo para os produtos cosméticos Premium (Euromonitor International, 2013). A população de baixa renda no Brasil representa 70% de seus habitantes ao considerar as classes C, D e E (Barki e Parente, 2010), sendo a classe C representada por 56% da população (Neri, 2012). Este é um mercado potencial para as empresas multinacionais (MNCs), que enfrentam desafios de fazer negócios no país, visto que a classe C opta por gastar parte de sua renda com produtos relacionados a beleza (Silva e Parente, 2007) e ainda há um pouco conhecimento sobre o comportamento de consumo na base da pirâmide. Portanto, o objetivo deste estudo é investigar e descrever o comportamento de consumo das mulheres brasileiras da classe C no setor de beleza, em relação aos produtos Mass Premium, melhorando o conhecimento no que diz respeito a essa população e ao tema proposto. Para atingir esse objetivo, o autor utilizou uma metodologia baseada em uma análise descritivas qualitativa em que foram entrevistadas 20 mulheres de todas as faixas etárias, que pertencem à classe C brasileira e citações foram usadas para fornecer a confirmação dos resultados da análise. Os resultados sugerem que, ao longo dos anos, houve de fato um movimento de trade up no consumo de produtos de beleza. Além disso, foram identificados cinco aspectos principais, que conduzem decisão de compra das mulheres de classe C, no setor de beleza: confiabilidade, qualidade, status, autoestima e bem-estar. Apesar das limitações de um estudo exploratório, espera-se que a pesquisa aumente o conhecimento sobre o mercado da base da pirâmide, especialmente no que diz respeito à indústria da beleza.

Reestruturação produtiva e terceirização : o caso dos trabalhadores das empresas contratadas pela Petrobrás no RN

This thesis is inserted on the discussion about the productive reframing and its reflexes concerning the world of work, in the current crisis stage in the capitalist way of production. This study deals with the impacts of outsourcing in relation to workers of companies subhired by Petrobras, in the State of Rio Grande do Norte, since decade of 1990. It is demonstrated that outsourcing in the oil sector, used mainly as a way to reduce costs of production, contributed to the raising of precarious conditions and relations of work. The transformation to the way of organization in the production, has intensified with the outsourcing, represented to the companies a bigger gain in productivity and a better control over the workers. These changings, that reconfigure the profile of the oil work force, allowed, among other things, reduction in numbers of the effective workers in the table of employees of Petrobras, the raising of relation concercing instable works, the raising in numbers of young workers, with a little or none qualification, reduction in the salary pattern of the professional class, illegal withholdment of labourite rights and the raising of risks to the health and security of the workers

Bound states of the Dirac equation for a class of effective quadratic plus inversely quadratic potentials

The Dirac equation is exactly solved for a pseudoscalar linear plus Coulomb-like potential in a two-dimensional world. This sort of potential gives rise to an effective quadratic plus inversely quadratic potential in a Sturm-Liouville problem, regardless the sign of the parameter of the linear potential, in sharp contrast with the Schrodinger case. The generalized Dirac oscillator already analyzed in a previous work is obtained as a particular case. (C) 2004 Elsevier B.V. All rights reserved.

Legitimacy and context: Implications for public sector reform in developing countries

This article examines the interplay between legitimacy and context as key determinants of public sector reform outcomes. Despite the importance of variables Such as legitimacy of public institutions, levels of civic morality and socio-economic realities, reform strategies often fail to take such contextual factors into account. The article examines, first, relevant literature both conceptual and empirical, including data from the World Values Survey project. It is argued that developing countries have distinctive characteristics which require particular reform strategies. The data analysed shows that in Latin American countries, there is no clear Correlation between confidence in public institutions and civic morality. Other empirical studies show that unemployment has a negative impact on the level of civic morality, while inequality engenders corruption. This suggests that poorer and socio-economically stratified countries face greater reform challenges owing to the lack of legitimacy of public institutions. The article concludes that reforms should focus on areas of governance that impact on poverty. This will in turn help produce more stable outcomes. Copyright (C) 2008 John Wiley & Sons, Ltd.

Study of a fuel cell cogeneration system applied to a Brazilian tertiary sector

In this paper, a methodology for the study of a molten carbonate fuel cell cogeneration system and applied to a computer center building is developed. This system permits the recovery of waste heat, available between 600°C and 700°C, which can be used to the production of steam, hot and cold water, hot and cold air, depending on the recuperation equipment associated. Initially, some technical information about the most diffusing types of the fuel cell demonstration in the world are presented. In conclusion, the fuel cell cogeneration system may have an excellent opportunity to strengthen the decentralized energy production in the Brazilian tertiary sector.

The Schwinger model on the null-plane

We study the Schwinger Model on the null-plane using the Dirac method for constrained systems. The fermion field is analyzed using the natural null-plane projections coming from the γ-algebra and it is shown that the fermionic sector of the Schwinger Model has only second class constraints. However, the first class constraints are exclusively of the bosonic sector. Finally, we establish the graded Lie algebra between the dynamical variables, via generalized Dirac bracket in the null-plane gauge, which is consistent with every constraint of the theory. © World Scientific Publishing Company.

Latin America and the Caribbean in the World Economy 2004: 2005 trends

Includes bibliography

Latin America and the Caribbean in the World Economy 2006: 2007 trends

Includes bibliography

Latin America and the Caribbean in the World Economy 2007: 2008 trends

Includes bibliography

Latin America and the Caribbean in the World Economy 2010-2011: The region in the decade of the emerging economies

Incluye Bibliografía