The evolution of the mass-metallicity relation in SDSS galaxies uncovered by astropaleontology

We have obtained the mass-metallicity (M-Z) relation at different lookback times for the same set of galaxies from the Sloan Digital Sky Survey, using the stellar metallicities estimated with our spectral synthesis code STARLIGHT. We have found that this relation steepens and spans a wider range in both mass and metallicity at higher redshifts. We have modelled the time evolution of stellar metallicity with a closed-box chemical evolution model, for galaxies of different types and masses. Our results suggest that the M-Z relation for galaxies with present-day stellar masses down to 10(10) M(circle dot) is mainly driven by the history of star formation and not by inflows or outflows.

Framework for Skew-Probit Links in Binary Regression

We review several asymmetrical links for binary regression models and present a unified approach for two skew-probit links proposed in the literature. Moreover, under skew-probit link, conditions for the existence of the ML estimators and the posterior distribution under improper priors are established. The framework proposed here considers two sets of latent variables which are helpful to implement the Bayesian MCMC approach. A simulation study to criteria for models comparison is conducted and two applications are made. Using different Bayesian criteria we show that, for these data sets, the skew-probit links are better than alternative links proposed in the literature.

The Impact of Foreign Direct Investment on International Trade: An Empirical Study of China

This paper investigates the impact of inward FDI (Foreign Direct Investment) on international trade of China empirically on the country level by using panel data from 1984 to 2007. Two separate transformed models which are based on the gravity equation and refer to the econometric models of some previous studies, are used in this paper to estimate the effect of FDI inflows on exports and imports respectively. The estimation results confirmed the complementary relationship between FDI inflows and trade of China both on exports and imports, which has also been supported by previous empirical studies.

Film som kommunikation : En studie av gymnasieungdomars filmarbete

The starting point for this work was a discussion between my supervisor and myself during my teaching training. The discussion concerned the appropriateness of allowing students make films with sexual content. Film gives young people the opportunity to express their feelings and broaden their views. If the film then disseminates to unknown people via in-ternet, which it most likely will do, maybe it is no longer so positive. The aim of this study is to shed light on various aspects of identity and ethics that are important to keep in mind when young people in school make films. These aspects are to avoid making young people vulnerable to abuse and improper influence. One aim is also to highlight the advantages of making films in school. The study is inspired by hermeneutic interpretive and based on qualitative interviews. The informants are four students at the age of 18-19 at two different schools in one municipality in Sweden.The results of the study show that it is important for the informants that the films are pro-duced in an aesthetically good way so that it appeals to the audience. Two of the infor-mants have a specific audience and make more conscious choices, so that the audience will understand what is said. The study shows that the more a filmmaker considers the audi-ence, the more consciously he or she uses film as communication. To get positive feedback is important, but it is mostly friends of the filmmakers that actually comment. To get nega-tive comments is regarded as a disadvantage when placing material on the internet. Howev-er, none of the informants in the study have received negative comments on what has been posted. The opinions about what the informants believe is inappropriate to post on inter-net or to make films about regards sexuality and violations. Earlier studies show that mate-rial can, because it is interesting to other people, become widespread. For this reason it is important for teachers to have conversations with students about their preferences and opinions on various issues. Adults need to interfere in the young people's world, while be-ing open to their opinions. Then the young people's value system will be built up and give them a safe tool that helps them to avoid improper influence.

Rule versus interaction function : evaluating regional aggregations of commuting flows in Sweden

The aim of this paper is to evaluate the performance of two divergent methods for delineating commuting regions, also called labour market areas, in a situation that the base spatial units differ largely in size as a result of an irregular population distribution. Commuting patterns in Sweden have been analyzed with geographical information system technology by delineating commuting regions using two regionalization methods. One, a rule-based method, uses one-way commuting flows to delineate local labour market areas in a top-down procedure based on the selection of predefined employment centres. The other method, the interaction-based Intramax analysis, uses two-way flows in a bottom-up procedure based on numerical taxonomy principles. A comparison of these methods will expose a number of strengths and weaknesses. For both methods, the same data source has been used. The performance of both methods has been evaluated for the country as a whole using resident employed population, self-containment levels and job ratios for criteria. A more detailed evaluation has been done in the Goteborg metropolitan area by comparing regional patterns with the commuting fields of a number of urban centres in this area. It is concluded that both methods could benefit from the inclusion of additional control measures to identify improper allocations of municipalities.

Simulation model using meta heuristic algorithms for achieving optimal arrangement of storage bins in a sawmill yard

Bin planning (arrangements) is a key factor in the timber industry. Improper planning of the storage bins may lead to inefficient transportation of resources, which threaten the overall efficiency and thereby limit the profit margins of sawmills. To address this challenge, a simulation model has been developed. However, as numerous alternatives are available for arranging bins, simulating all possibilities will take an enormous amount of time and it is computationally infeasible. A discrete-event simulation model incorporating meta-heuristic algorithms has therefore been investigated in this study. Preliminary investigations indicate that the results achieved by GA based simulation model are promising and better than the other meta-heuristic algorithm. Further, a sensitivity analysis has been done on the GA based optimal arrangement which contributes to gaining insights and knowledge about the real system that ultimately leads to improved and enhanced efficiency in sawmill yards. It is expected that the results achieved in the work will support timber industries in making optimal decisions with respect to arrangement of storage bins in a sawmill yard.

NDVI With Artificial Neural Networks For SRTM Elevation Model Improvement – Hydrological Model Application

Digital elevation model (DEM) plays a substantial role in hydrological study, from understanding the catchment characteristics, setting up a hydrological model to mapping the flood risk in the region. Depending on the nature of study and its objectives, high resolution and reliable DEM is often desired to set up a sound hydrological model. However, such source of good DEM is not always available and it is generally high-priced. Obtained through radar based remote sensing, Shuttle Radar Topography Mission (SRTM) is a publicly available DEM with resolution of 92m outside US. It is a great source of DEM where no surveyed DEM is available. However, apart from the coarse resolution, SRTM suffers from inaccuracy especially on area with dense vegetation coverage due to the limitation of radar signals not penetrating through canopy. This will lead to the improper setup of the model as well as the erroneous mapping of flood risk. This paper attempts on improving SRTM dataset, using Normalised Difference Vegetation Index (NDVI), derived from Visible Red and Near Infra-Red band obtained from Landsat with resolution of 30m, and Artificial Neural Networks (ANN). The assessment of the improvement and the applicability of this method in hydrology would be highlighted and discussed.

Delaware Reservoirs’ Drought Risk Assessment: A Paleo View

The Delaware River provides half of New York City's drinking water, is a habitat for wild trout, American shad and the federally endangered dwarf wedge mussel. It has suffered four 100‐year floods in the last seven years. A drought during the 1960s stands as a warning of the potential vulnerability of the New York City area to severe water shortages if a similar drought were to recur. The water releases from three New York City dams on the Delaware River's headwaters impact not only the reliability of the city’s water supply, but also the potential impact of floods, and the quality of the aquatic habitat in the upper river. The goal of this work is to influence the Delaware River water release policies (FFMP/OST) to further benefit river habitat and fisheries without increasing New York City's drought risk, or the flood risk to down basin residents. The Delaware water release policies are constrained by the dictates of two US Supreme Court Decrees (1931 and 1954) and the need for unanimity among four states: New York, New Jersey, Pennsylvania, and Delaware ‐‐ and New York City. Coordination of their activities and the operation under the existing decrees is provided by the Delaware River Basin Commission (DRBC). Questions such as the probability of the system approaching drought state based on the current FFMP plan and the severity of the 1960s drought are addressed using long record paleo‐reconstructions of flows. For this study, we developed reconstructed total annual flows (water year) for 3 reservoir inflows using regional tree rings going back upto 1754 (a total of 246 years). The reconstructed flows are used with a simple reservoir model to quantify droughts. We observe that the 1960s drought is by far the worst drought based on 246 years of simulations (since 1754).

Ajuste macroeconômico e empréstimos externos no Brasil, 1995-2004

O presente estudo analisa a o impacto das restrições macroeconômicas, que emergiram no bojo da crise cambial de 1999, sobre a contratação de empréstimos externos pelo governo brasileiro junto às agências multilaterais de crédito, entre 1995-2004. A idéia básica é que a estratégia de equacionamento da crise externa teve reflexos diretos sobre o comportamento dos empréstimos contratados junto aos Multilateral Development Banks. Mais especificamente, o conjunto de políticas adotadas pelo governo brasileiro acabou promovendo tanto uma mudança na natureza como uma substancial redução na contratação de empréstimos principalmente junto ao Banco Mundial e ao Banco Inter americano de Desenvolvimento. Em decorrência, a estratégia de ajuste adotada, apesar do seu mérito, acabou privando o governo brasileiro de uma fonte barata de recursos e comprometendo o investimento do setor público.

Ajustamento da taxa de câmbio após a crise cambial

O trabalho investiga o ajustamento da taxa de câmbio na transição de um regime de câmbio fixo com taxa de câmbio real apreciada para um regime flutuante. Pretendemos argumentar, teórica e empiricamente, que a depreciação da taxa de câmbio, bem acima da apreciação acumulada no período, que se observou nos diversos países que passaram por esta mudança de regime, é esperada e não se confunde com a análise de overshooting de Dornbusch. Em linhas bastante gerais nosso argumento é que esta depreciação excessiva pode ser o mecanismo de correção do crescimento da dívida externa, que durante o período de apreciação cambial esteve acima de sua taxa de estado estacionário. A intensidade e duração deste ajuste depende, entre outras coisas, da possibilidade de novos empréstimos, da taxa de juros paga sobre os mesmos e da resposta da balança comercial à taxa de câmbio.

O método das opções reais aplicado na avaliação das oportunidades de investimento no setor de seguros

Esta dissertação tem como objetivo demonstrar a validade do método de análise da avaliação das oportunidades de investimentos que utiliza a Teoria das Opções Reais. De forma a demonstrar a aplicabilidade desta metodologia de avaliação, será exemplificado, com base no modelo das opções reais, uma oportunidade de investimento no setor de seguros. As opções reais fecham a brecha entre as finanças e o planejamento estratégico introduzindo um meio para incorporar o impacto da incerteza implícita nas oportunidades de investimento, e ao mesmo tempo considerando como as ações gerenciais podem limitar as possíveis perdas ou capitalizar os possíveis ganhos nos projetos de investimento. Este processo de avaliação não direciona somente os administradores a focar suas atenções nas diferentes oportunidades e alternativas estratégicas, mas fornece também uma metodologia sistemática para medir a influencia das ações contingentes sobre o próprio risco e valor do projeto. Os métodos tradicionais de avaliação dos investimentos assumem que os administradores adotem um comportamento passivo à implementação dos projetos, considerando somente o valor dos fluxos de caixa esperados dos mesmos. A partir da teoria de precificação das opções financeiras, as opções reais expandem o valor global do projeto incorporando os potenciais ganhos e limitando as possíveis perdas. O modelo de opções reais permite aos administradores alavancar o valor do acionista em um ambiente de negócios dinâmico considerando a possibilidade de uma gestão ótima das opções estratégicas e operacionais existentes. Tipicamente, o ativo subjacente é o valor bruto dos fluxos de caixa esperados do projeto, mas considerando a incerteza, o valor total do projeto deve considerar o valor implícito das opções reais presentes nas oportunidades de investimento. A flexibilidade gerencial, que permite adaptar as decisões futuras as mudanças inesperadas do mercado, representa um fonte crucial de valor agregado em um ambiente dinâmico. Muitas opções reais presentes nos projetos e que interagem entre si, podem ocorrer em paralelo ou seqüencialmente, de maneira que o valor combinado destas opções seja diferente da simples soma algébrica das opções individuais.

Gestão da segurança da informação: certificação digital

More over, the information has become the main asset of the institutions. Being thus, the Information Security (IS) is getting attention as one of the activities of extreme importance in the corporations. Guarantee the confidentiality, integrity, availability, no deny and legality becomes something very important for the day-by-day of the businesses. An analysis of the risk, passing through the assessment of the threats and vulnerabilities, is mandatory to let grow the activities of the institutions. Digital Certification came into IS to guarantee the Not Deny (ND) because it makes the unquestioned identification of the person that makes the action. Therefore, Information Security can be defined as a knowledge field focused in the protection of the information assets against: unauthorized access, improper modifications, not availability, deny of authorship and illegality.

China na América Latina: uma análise da perspectiva dos investimentos diretos estrangeiros

Este trabalho discute a dinâmica dos investimentos diretos da China para as economias mundiais e, particularmente, para a América do Sul. Após mais de três décadas de intenso crescimento econômico e de forte aumento de sua participação no comércio mundial, a economia chinesa vem realizando crescentes investimentos no exterior. No caso das economias da América do Sul, a influência comercial chinesa tem alterado substancialmente a importância de tradicionais parceiros comerciais e mesmo a importância do Brasil na região. Os fluxos de investimentos diretos, mesmo que ainda em pequena escala, indicam o mesmo caminho de aumento de sua influência sobre as diversas economias da região, especialmente na exploração de fontes de materiais primais e de alimentos. Com isso, a China reforça não somente pela via comercial, mas também pelos influxos de investimentos, a característica agrícolaprimária das economias da região.

Exchange rate policies, patterns of specialization and economic development: theory and evidence in developing countries

The objectives of this paper are twofold. First, it intends to provide theoretical elements to analyze the relation between real exchange rates and economic development. Our main hypothesis is very much in line with the Dutch disease literature, and states that competitive currencies contribute to the existence and maintenance of the anufacturing sector in the economy. This, in turn, brings about higher growth rates in the long run, given the existence of increasing returns in the industrial sector, and its importance in generating echnological change and increasing productivity in the overall economy. The second objective of this paper is empirical. It intends to analyze examples of successful exchange rate policies, such as Chile and Indonesia in the eighties, as a benchmark for comparison with countries where currency overvaluation has taken place, such as Brazil. In the latter case, the local currency is being inflated by large capital inflows, due to high domestic interest rates and to a boom in demand and prices of commodities in the international markets. It will be argued that the industrial sector bears most of the burden when the currency appreciates, and that Brazil risks at deindustrialization if there are no changes in the exchange rate regime

A taxa de câmbio no centro da teoria do desenvolvimento

This paper presents the main ideas of structuralist development macroeconomics – the theory behind new developmentalism. Its focus is on the exchange rate that is positioned for the first time in the core of development economics. Economic theory usually views the exchange rate as a short term problem to be discussed in open macroeconomics. Structuralist development macroeconomics argues that there is in developing countries a tendency to the cyclical overvaluation of the exchange rate caused by the lack of neutralization of the Dutch disease and by excessive capital inflows. In consequence it views the exchange rate as chronically overvalued, and, for that reason, a major obstacle to economic growth. In the development process, the exchange rate has the role of light switch that connects or disconnects the national business enterprises utilizing technology in the world state of the art from world markets