A map for heavy inertial particles in fluid flows

We introduce a map which reproduces qualitatively many fundamental properties of the dynamics of heavy particles in fluid flows. These include a uniform rate of decrease of volume in phase space, a slow-manifold effective dynamics when the single parameter $s$ (analogous of the Stokes number) approaches zero, the possibility of fold caustics in the "velocity field", and a minimum, as a function of $s$, of the Lyapunov (Kaplan-Yorke) dimension of the attractor where particles accumulate.Comment: 10 pages, 5 figure

The return of the membrane paradigm? Black holes and strings in the water tap

Several general arguments indicate that the event horizon behaves as a stretched membrane. We propose using this relation to understand gravity and dynamics of black objects in higher dimensions. We provide evidence that (i) the gravitational Gregory-Laflamme instability has a classical counterpart in the Rayleigh-Plateau instability of fluids. Each known feature of the gravitational instability can be accounted for in the fluid model. These features include threshold mode, dispersion relation, time evolution and critical dimension of certain phase transitions. Thus, we argue that black strings break in much the same way as water from a faucet breaks up into small droplets. (ii) General rotating black holes can also be understood with this analogy. In particular, instability and bifurcation diagrams for black objects can easily be inferred. This correspondence can and should be used as a guiding tool to understand and explore physics of gravity in higher dimensions.Comment: This essay received an honorable mention in the Gravity Research Foundation Essay Competition, 2007. v2: Published versio

Black Lawyers Matter: Enduring Racism in American Law Firms

Scholars and practitioners have extensively examined patterns of racial inequality in U.S. corporate law firms. In the corporate bar, pull factors that have long shaped legal professionals’ careers include promotions, outside job offers, and family priorities that may lead to leaving the labor force altogether. Push factors, such as discrimination, problems with management, and work-life conflict, also precipitate work transitions. Beyond corporate firms, however, an urgent question remains open to empirical scrutiny: How does race affect career moves in the contemporary American legal profession? In this Article, I address this question drawing upon data from the first nationally representative, longitudinal survey of U.S. lawyers. This study is one of few that uses event history analysis as a statistical technique to examine legal careers. It also draws on in-depth interviews to unravel how lawyers view their experiences at firms. These legal professionals detail how race influences assignment distribution and promotion within American law firms. Assessment of work histories of over 4,000 law school graduates, from the time they were admitted to practice in the year 2000, shows that, all else being equal, Black lawyers are pushed out of private law firms at much higher rates than white lawyers. As Black lawyers continue to strive for racial equality, these results indicate that race-conscious remedies remain critical not only for the future of law firms, but also for the broader legal profession

International Trade v. Intellectual Property Lawyers:Globalization and the Brazilian Legal Profession

In the context of globalization, this work analyzes a distinctive characteristic of the Brazilian legal profession. Namely, intellectual property (IP) lawyers, who played important roles in opening the Brazilian economy and who were key players in cross-border transactions, are now losing ground to their peers with respect to expertise in international trade. The thesis of this article is that the manner in which Brazilian lawyers are being educated is problematic. Generally, Brazilian legal education has become degraded and provincial. Yet, Brazilian international trade lawyers, unlike Brazilian IP lawyers, have overcome their deficient legal training by seeking legal education abroad. By traveling overseas, especially to the United States, international trade lawyers are exposed to an education and a set of best practices that stress not just domestic law from one or another country, but laws from different jurisdictions. International trade lawyers in Brazil are now “global lawyers,” which enables them to deal more effectively with their country’s expanding economy, and it supports the argument that globalization matters for both today’s law students and the legal profession

VALUES OF ECOLOGICAL GOODS AND SERVICES PROVIDED BY WETLAND FOR POLICY DEVELOPMENT IN SASKATCHEWAN

The economic integration between natural and managed ecosystem is a growing area of interest to agricultural policy makers. The complexity of such integration has many different implications for the development of appropriate policy. Often, management of wetland resources located on private land involves a perceived conflict between social and private interests since landowners usually cannot benefit economically from wetlands on site unless they convert them to alternative uses such as agricultural crops. In general it has been shown that the market will undersupply public goods and/or oversupply public bads, and that often public organizations (e.g. government) have a role to ensure the provision of public goods, such as many categories of ecological goods and services (EG&S). The development of effective policy to ensure efficient provision of EG&S is hampered by a poor understanding of the preferences and values of EG&S held by farmers and society. Thus, the present work proposes the investigation of the preferences of society with respect to EG&S provision in the province of Saskatchewan. Using data from a survey of Saskatchewan residents, the willingness to pay (WTP) for wetland attributes was quantified. In addition, participant’s perceived share of conservation responsibilities were assessed. As indicated by the results from two logit models that were developed based on survey responses, respondents felt that all of the wetland management attributes are significant factors in the choice of a wetland management scenario, and ceteris paribus, higher levels of any single attribute increases the probability that a management scenario is selected. In other words, respondents prefer those wetland management scenarios which result in higher levels of riparian area, wildlife population and water quality. Indeed, the results from management scenarios presented in this study suggest that when considering wetland preservation in Saskatchewan agricultural areas, participants would most likely prefer policies that provide water quality. Overall, this study is expected to inform policy makers of society’s preferences towards EG&S provision in Saskatchewan

International Trade v. International Property Lawyers: Globalization and the Brazilian Legal Profession

This work analyzes a distinctive characteristic of the globalizing Brazilian legal profession. Namely, intellectual property (IP) lawyers who once were leaders in opening the Brazilian economy and were key players in cross-border transactions are now losing ground to their peers with an expertise in international trade. The thesis of this article is that the manner in which Brazilian lawyers are being educated is in shambles. Generally speaking, Brazilian legal education has, overall, become degraded and provincial. Yet, Brazilian international trade lawyers, unlike Brazilian IP-lawyers, have overcome their deficient legal training by seeking legal education abroad. By traveling overseas, especially to the United States, international trade lawyers are exposed to an education and a set of best practices that stress not just domestic, Brazilian law, but laws from different jurisdictions. That international trade lawyers in Brazil are now ‘global lawyers,’ enables them to deal more effectively with their country’s expanding economy, and it supports the argument that globalization matters for both today’s law students and the legal profession

Localization of Software and Web Pages

Diferentes autores têm diferentes ideias em relação às competências de um tradutor e de um localizador e às diferenças entre ambos. A tradução é uma atividade que se centra mais no texto e na transmissão do seu significado de uma língua de partida para uma língua de chegada, para que este seja facilmente entendido nesta última. A localização, para além de se preocupar com os aspetos relacionados com a tradução, preocupa-se com a forma como esse texto é apresentado, para que se integre não só na língua mas também na cultura de chegada e que seja apresentado como se fosse criado para aquela cultura, país ou região. Para alcançar esse objetivo, mais especificamente no caso da localização de páginas web, o localizador deverá ter competências não só ao nível de software de processamento de texto e gestão de projetos, mas também ao nível de programas específicos para a criação de páginas web e software de design. Por vezes, o localizador necessita de alterar não só o texto como também possíveis imagens ou a forma como estas são apresentadas, sendo o exemplo mais óbvio o caso de localização de páginas web para países onde a orientação da escrita se faz da direita para a esquerda, o que leva a que seja necessário uma alteração do design e da interface da página para além da própria tradução do texto. No entanto, estes conceitos são interdependentes, pois uma boa localização começa numa boa tradução e uma boa tradução tem de ter em conta a localização. Todos estes aspetos são essenciais para a globalização de um produto.Different authors have different opinions about the competencies of a translator and a localizer and the differences between both. Translation focuses on the text and transmitting its meaning from a source language into a target language, so that this text is easily understood on said target language. Localization, besides being concerned with the translation aspect, it is also concerned with the way this text is presented, so that this text feels natural not only in the source language but in the source culture as well, as if it had been written originally in the target language, its culture, country or region. To accomplish that, more specifically ininfo:eu-repo/semantics/publishedVersio

Determination of the drag coefficient of an autonomous solar lighting column using wind tunnel simulation and computational analysis

Dupla diplomação com a UTFPR - Universidade Tecnológica Federal do ParanáPhotovoltaic solar panels have many applications and among them are the autonomous solar lighting columns, which has been growing in popularity in urban and rural enviroments. These columns are installed in open regions and have their structure exposed to the mechanical actions imposed by the wind, so they need to be correctly designed to support them. There are aerodynamic variables that must be determined for the design of these columns, especially the drag coefficient, a property linked to the geometry of a body, which represents its interaction with a flowing fluid. Due to the complexity of determining these variables, experimental methods are constantly used to obtain these values. Classically, wind tunnel simulations are used for this purpose, but they can be expensive and difficult to perform, so that fluid computational analysis has been widely applied to replace physical analysis. In this work, the drag coefficient of an autonomous solar illumination column is determined by wind tunnel simulations and computational analysis using various body positions in relation to the direction of flow. The drag coefficient determined using wind tunnel simulations varies between 0.65 and 0.80 while for computational methods it varies between 0.43 and 0.73. With the obtained results it is possible to perform a verification of the fidelity of the data obtained by computational means when compared to those obtained through the wind tunnel simulations obtaining an average error of 9.2% and 27.2% for the computational methods used.Painéis solares fotovoltaicos possuem muitas aplicações e entre elas estão as colunas de iluminação solar autônomas, que vem crescendo em popularidade principalmente nos ambientes urbanos e industriais. Estas colunas são instaladas em regiões abertas e têm sua estrutura exposta às ações mecânicas impostas pelo vento, desta forma, precisam ser corretamente projetadas para suporta-las. Existem variáveis aerodinâmicas que devem ser determinadas para o projeto dessas colunas em especial o coeficiente de arrasto, propriedade ligada à geometria de um corpo, que representa a interação deste com um fluido em escoamento. Devido à complexidade de determinação dessas variáveis, métodos experimentais são constantemente utilizados para obter estes valores. Classicamente, as simulações em túnel de vento são utilizadas para este propósito, porém, estas podem ser caras e de difícil realização, de modo que as análises computacionais fluidodinâmicas vêm sendo muito aplicadas para substituir as análises físicas. Neste trabalho, o coeficiente de arrasto de uma coluna de iluminação solar autônoma é determinado por meio de simulações em túnel de vento e por meio de análises computacionais utilizando diversos posicionamentos do corpo em relação à direção do escoamento. O coeficiente de arrasto determinado utilizando as simulações em tunel de vento varia entre 0,65 e 0,80 enquanto para os métodos computacionais varia entre 0,43 e 0,73. Com os resultados obtidos é possível realizar uma verificação da fidelidade dos dados obtidos por meios computacionais quando comparados aos obtidos através das simulações em túnel de vento obtendo-se um erro médio de 9,2% e 27,2% para os métodos computacionais utilizados

Efficiency tests in the Iberian stock markets

This paper investigates the efficiency of the two major stock indexes of the Iberian Peninsula, the Portuguese Stock Index (PSI-20) and the Spanish Stock Index (IBEX-35). We used daily data from January 1993 to September 2001 for the Portuguese stock index and daily data from October 1990 to September 2001 for the Spanish stock index. Serial correlations, unit root tests and variance ratio tests are used to test the efficiency of these two stock indexes. Although the complementary of these tests, we used all of them to get a higher robustness of the conclusions. We examined serial correlation coefficients for successive stock index changes to test whether they are statistically equal to zero to establish the random walk nature of stock indexes. The augmented Dickey-Fuller (ADF) test are used to test the null hypothesis that the series has a unit root and the variance ratio tests are used to examine the random walk hypothesis for the series of these two stock indexes. The results of the serial correlations, unit root tests and variance ratio tests provide ambiguous evidence for the random walk hypothesis. The empirical evidence from the unit root tests do not reject the efficient market hypothesis for the two stock indexes, while the results from the variance ratio tests and serial correlations do.stock indexes, market efficiency, unit roots