Strong cosmic censorship: The nonlinear story

A satisfactory formulation of the laws of physics entails that the future evolution of a physical system should be determined from appropriate initial conditions. The existence of Cauchy horizons in solutions of the Einstein field equations is therefore problematic, and expected to be an unstable artifact of General Relativity. This is asserted by the Strong Cosmic Censorship Conjecture, which was recently put into question by an analysis of the linearized equations in the exterior of charged black holes in an expanding universe. Here, we numerically evolve the nonlinear Einstein-Maxwell-scalar field equations with a positive cosmological constant, under spherical symmetry, and provide strong evidence that mass inflation indeed does not occur in the near extremal regime. This shows that nonlinear effects might not suffice to save the Strong Cosmic Censorship Conjecture.Comment: 9 pages, 8 figures. v2: Matches published versio

Political competition and the allocation of public investment in Mexico

This paper examines the causality between central government spending in regions and local elections, in an environment of increasing electoral competition and a undefined decentralisation. This study examines Mexican elections during the period 1990-1995 where the main party started loosing part of its influence and there were many claims of use of the budget to favour the central governing party. We employ data on public investment and municipalities ruled by the PRI in each Mexican region. The evidence shows that there is opportunistic behaviour of the central government using public investment to gain local control of pressures for decentralisation.

Calculation of the variance in surveys of the economic climate

Public opinion surveys have become progressively incorporated into systems of official statistics. Surveys of the economic climate are usually qualitative because they collect opinions of businesspeople and/or experts about the long-term indicators described by a number of variables. In such cases the responses are expressed in ordinal numbers, that is, the respondents verbally report, for example, whether during a given trimester the sales or the new orders have increased, decreased or remained the same as in the previous trimester. These data allow to calculate the percent of respondents in the total population (results are extrapolated), who select every one of the three options. Data are often presented in the form of an index calculated as the difference between the percent of those who claim that a given variable has improved in value and of those who claim that it has deteriorated. As in any survey conducted on a sample the question of the measurement of the sample error of the results has to be addressed, since the error influences both the reliability of the results and the calculation of the sample size adequate for a desired confidence interval. The results presented here are based on data from the Survey of the Business Climate (Encuesta de Clima Empresarial) developed through the collaboration of the Statistical Institute of Catalonia (Institut d’Estadística de Catalunya) with the Chambers of Commerce (Cámaras de Comercio) of Sabadell and Terrassa.Economic climate, variances, sampling methods.

Estudo da dispersão de poluentes, aplicado a um parque de energia das ondas

Mestrado em Meteorologia e Oceanografia FísicaEste trabalho resultou da minha colaboração na Martifer Energy Systems no âmbito do projecto FLOW. Ao longo deste projecto foi necessário a compreensão da dinâmica da região de instalação de um dispositivo para extracção da energia das ondas, com especial importância para o regime de correntes. Para tal foi implementado o modelo numérico oceanográfico ROMS AGRIF e que foi utilizado para o estudo de diversos parâmetros, como temperatura e a salinidade. Um estudo de movimento de flutuadores lagrangeanos foi efectuado com vista à estimação de um cenário extremo em caso de falha no sistema de amarração do dispositivo ou fuga de fluidos hidráulicos e que permitam analisar um padrão no seu deslocamento face à presença de condições meteorológicas semelhantes. ABSTRACT: This work resulted in my collaboration in the FLOW project at Martifer Energy Systems. During the development of this project it was necessary to understand the dynamics of the instalation region of a device for extracting energy from ocean waves, with particular relevance to the current regime. It has installed the oceanographic numerical model ROMS AGRIF and was used to study various parameters such as temperature and salinity. A motions study of lagrangean floats was made in case of failure of the mooring system of the device, leakage of hydraulic fluid and for analyzing a pattern in its movement against the presence of adverse weather conditions

Calculation of the variance in surveys of the economic climate.

Public opinion surveys have become progressively incorporated into systems of official statistics. Surveys of the economic climate are usually qualitative because they collect opinions of businesspeople and/or experts about the long-term indicators described by a number of variables. In such cases the responses are expressed in ordinal numbers, that is, the respondents verbally report, for example, whether during a given trimester the sales or the new orders have increased, decreased or remained the same as in the previous trimester. These data allow to calculate the percent of respondents in the total population (results are extrapolated), who select every one of the three options. Data are often presented in the form of an index calculated as the difference between the percent of those who claim that a given variable has improved in value and of those who claim that it has deteriorated. As in any survey conducted on a sample the question of the measurement of the sample error of the results has to be addressed, since the error influences both the reliability of the results and the calculation of the sample size adequate for a desired confidence interval. The results presented here are based on data from the Survey of the Business Climate (Encuesta de Clima Empresarial) developed through the collaboration of the Statistical Institute of Catalonia (Institut d’Estadística de Catalunya) with the Chambers of Commerce (Cámaras de Comercio) of Sabadell and Terrassa.Economic climate, variances, sampling methods.

Political competition and the allocation of public investment in Mexico

This paper examines the causality between central government spending in regions and local elections, in an environment of increasing electoral competition and a undefined decentralisation. This study examines Mexican elections during the period 1990-1995 where the main party started loosing part of its influence and there were many claims of use of the budget to favour the central governing party. We employ data on public investment and municipalities ruled by the PRI in each Mexican region. The evidence shows that there is opportunistic behaviour of the central government using public investment to gain local control of pressures for decentralisation

Calculation of the variance in surveys of the economic climate

Public opinion surveys have become progressively incorporated into systems of official statistics. Surveys of the economic climate are usually qualitative because they collect opinions of businesspeople and/or experts about the long-term indicators described by a number of variables. In such cases the responses are expressed in ordinal numbers, that is, the respondents verbally report, for example, whether during a given trimester the sales or the new orders have increased, decreased or remained the same as in the previous trimester. These data allow to calculate the percent of respondents in the total population (results are extrapolated), who select every one of the three options. Data are often presented in the form of an index calculated as the difference between the percent of those who claim that a given variable has improved in value and of those who claim that it has deteriorated

NOTAS SOBRE O PROGRAMA ESCREVA SEU FUTURO

Sob inspiração dos artigos discutidos durante o curso Questões Históricas e Filosóficas da Educação, este texto tem o objetivo de analisar o processo de construção de currículos/práticas e seus efeitos na vida das mulheres na educação de jovens e adultos. Em articulação com os conceitos de interseccionalidade, feminismo negro e desigualdades raciais, buscamos ouvir as vozes dos sujeitos da EJA para compreender uma proposta curricular outra, construída na periferia da cidade do Rio de Janeiro.  Abarcar a participação social e as memórias dessas mulheres tornou-se também mais um de nossos desafios