Stability of the curvature perturbation in dark sectors` mutual interacting models

We consider perturbations in a cosmological model with a small coupling between dark energy and dark matter. We prove that the stability of the curvature perturbation depends on the type of coupling between dark sectors. When the dark energy is of quintessence type, if the coupling is proportional to the dark matter energy density, it will drive the instability in the curvature perturbations: however if the coupling is proportional to the energy density of dark energy, there is room for the stability in the curvature perturbations. When the dark energy is of phantom type, the perturbations are always stable, no matter whether the coupling is proportional to the one or the other energy density. (C) 2008 Elsevier B.V. All rights reserved.

Observational constraints on the dark energy and dark matter mutual coupling

We examine different phenomenological interaction models for Dark Energy and Dark Matter by performing statistical joint analysis with observational data arising from the 182 Gold type la supernova samples, the shift parameter of the Cosmic Microwave Background given by the three-year Wilkinson Microwave Anisotropy Probe observations, the baryon acoustic oscillation measurement from the Sloan Digital Sky Survey and age estimates of 35 galaxies. Including the time-dependent observable, we add sensitivity of measurement and give complementary results for the fitting. The compatibility among three different data sets seem to imply that the coupling between dark energy and dark matter is a small positive value, which satisfies the requirement to solve the coincidence problem and the second law of thermodynamics, being compatible with previous estimates. (c) 2008 Elsevier B.V. All rights reserved.

Effects of Crossing Saddle Coil Conductors: Electric Length X Mutual Inductance

In magnetic resonance imaging (MRI), either on human or animal studies, the main requirements for radiofrequency (RF) coils are to produce a homogeneous RF field while used as a transmitter coil and to have the best signal-to-noise ratio (SNR) while used as a receiver. Besides, they need to be easily frequency adjustable and have input impedance matching 50 Omega to several different load conditions. New theoretical and practical concepts are presented here for considerable enhancing of RF coil homogeneity for MRI experiments on small animals. To optimize field homogeneity, we have performed simulations using Blot and Savart law varying the coil`s window angle, achieving the optimum one. However, when the coil`s dimensions are the same order of the wave length and according to transmission line theory, differences in electrical length and effects of mutual inductances between adjacent strip conductors decrease both field homogeneity and SNR. The problematic interactions between strip conductors by means of mutual inductance were eliminated by inserting crossings at half electrical length, avoiding distortion on current density, thus eliminating sources of field inhomogeneity. Experimental results show that measured field maps and simulations are in good agreement. The new coil design, dubbed double-crossed saddle described here have field homogeneity and SNR superior than the linearly driven 8-rung birdcage coil. One of our major findings was that the effects of mutual inductance are more significant than differences in electrical length for this frequency and coil dimensions. In vitro images of a primate Cebus paela brain were acquired, confirming double-crossed saddle superiority. (C) 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 37B: 193-201, 2010

Medical treatment and the good death: an ethical analysis of euthanasia, physician assisted suicide, and the right to die

Frequent advances in medical technologies have brought fonh many innovative treatments that allow medical teams to treal many patients with grave illness and serious trauma who would have died only a few years earlier. These changes have given some patients a second chance at life, but for others. these new treatments have merely prolonged their dying. Instead of dying relatively painlessly, these unfortunate patients often suffer from painful tenninal illnesses or exist in a comatose state that robs them of their dignity, since they cannot survive without advanced and often dehumanizing forms of treatment. Due to many of these concerns, euthanasia has become a central issue in medical ethics. Additionally, the debate is impacted by those who believe that patients have the right make choices about the method and timing of their deaths. Euthanasia is defined as a deliberate act by a physician to hasten the death of a patient, whether through active methods such as an injection of morphine, or through the withdrawal of advanced forms of medical care, for reasons of mercy because of a medical condition that they have. This study explores the question of whether euthanasia is an ethical practice and, as determined by ethical theories and professional codes of ethics, whether the physician is allowed to provide the means to give the patient a path to a "good death," rather than one filled with physical and mental suffering. The paper also asks if there is a relevant moral difference between the active and passive forms of euthanasia and seeks to define requirements to ensure fully voluntary decision making through an evaluation of the factors necessary to produce fully informed consent. Additionally, the proper treatments for patients who suffer from painful terminal illnesses, those who exist in persistent vegetative states and infants born with many diverse medical problems are examined. The ultimate conclusions that are reached in the paper are that euthanasia is an ethical practice in certain specific circumstances for patients who have a very low quality of life due to pain, illness or serious mental deficits as a result of irreversible coma, persistent vegetative state or end-stage clinical dementia. This is defended by the fact that the rights of the patient to determine his or her own fate and to autonomously decide the way that he or she dies are paramount to all other factors in decisions of life and death. There are also circumstances where decisions can be made by health care teams in conjunction with the family to hasten the deaths of incompetent patients when continued existence is clearly not in their best interest, as is the case of infants who are born with serious physical anomalies, who are either 'born dying' or have no prospect for a life that is of a reasonable quality. I have rejected the distinction between active and passive methods of euthanasia and have instead chosen to focus on the intentions of the treating physician and the voluntary nature of the patient's request. When applied in equivalent circumstances, active and passive methods of euthanasia produce the same effects, and if the choice to hasten the death of the patient is ethical, then the use of either method can be accepted. The use of active methods of euthanasia and active forms of withdrawal of life support, such as the removal of a respirator are both conscious decisions to end the life of the patient and both bring death within a short period of time. It is false to maintain a distinction that believes that one is active killing. whereas the other form only allows nature to take it's course. Both are conscious choices to hasten the patient's death and should be evaluated as such. Additionally, through an examination of the Hippocratic Oath, and statements made by the American Medical Association and the American College of physicians, it can be shown that the ideals that the medical profession maintains and the respect for the interests of the patient that it holds allows the physician to give aid to patients who wish to choose death as an alternative to continued suffering. The physician is also allowed to and in some circumstances, is morally required, to help dying patients whether through active or passive forms of euthanasia or through assisted suicide. Euthanasia is a difficult topic to think about, but in the end, we should support the choice that respects the patient's autonomous choice or clear best interest and the respect that we have for their dignity and personal worth.

Models of Community Investment and Partnership Strategies and Processes for Ensuring Mutual Benefit between Institution and Community

Institutions continue to face increasing pressure from faculty, students, and other concerned constituents to divest endowment holdings from perceived social injustices. In this report, investment officers and advisory committee members offer insight into institutional practices used to respond to these concerns through the adoption of socially responsible investment policies and other socially responsible investment options. Contacts offer recommendations on balancing the administration’s fiduciary responsibility to ensure maximum endowment returns with the social concerns of institutional constituents.

Optimal performance fee and flow of funds in asset management contracts

This paper investigates the importance of ow of funds as an implicit incentive in the asset management industry. We build a two-period bi- nomial moral hazard model to explain the trade-o¤s between ow, per- formance and fees where e¤ort depends on the combination of implicit ( ow of funds) and explicit (performance fee) incentives. Two cases are considered. With full commitment, the investor s relevant trade-o¤ is to give up expected return in the second period vis-à-vis to induce e¤ort in the rst period. The more concerned the investor is with today s pay- o¤, the more willing he will be to give up expected return in the second period by penalizing negative excess return in the rst period. Without full commitment, the investor learns some symmetric and imperfect infor- mation about the ability of the manager to obtain positive excess return. In this case, observed returns reveal ability as well as e¤ort choices. We show that powerful implicit incentives may explain the ow-performance relationship with a numerical solution. Besides, risk aversion explains the complementarity between performance fee and ow of funds.

Homem e risco: do oráculo à lei Sarbanes-Oxley

O presente trabalho aborda a relação histórica entre o Homem e o Risco, com ênfase nas relações contemporâneas, passando pela Ética Empresarial e pela Governança Corporativa, que têm por objetivo disciplinar as relações do capital com base nos princípios de eqüidade, transparência e prestação de contas, além do respeito às leis, regulamentos, normas, tanto formais quanto informais ou de mercado, e os aspectos éticos intrínsecos e culminando com a Lei Sarbanes-Oxley. Mais do que aproximar o investimento da produção, esse conjunto alicerça a confiança mútua, tornando-se arena de negócios entre atraídos e atraentes, ou seja, investidores e empresas. Estabelece, também, uma oportunidade para as empresas aumentarem suas origens por ação direta do patrimônio líquido, não implicando, portanto, em ônus dissociado do retorno, premiando, sob vários enfoques, a rentabilidade com responsabilidade social e percepção dos outros públicos inerentes ao negócio - stakeholders.

The EU-Mercosul free trade agreement: Quantifying mutual gains

We identify trade in goods opportunities in a EU-Mercosul free trade area. Gains for Mercosul are rather concentrated, being mostly associated to a few agricultural commodities nowadays facing high protection barriers. EU gains are evenly spread, comprising a variety of market penetration possibilities. Trade deviation by the EU products is never higher than trade creation, confirming their international competitiveness and signalling that a great distortion of Mercosul’s imports won’t take place. Balanced gains exist for both sides; for Mercosul, the agreement can act as a first serious trial for future liberalisations with other developed partners, and as a warning on needed competitiveness improvements.

Hedge Funds como Potencializadores de Ataques Especulativos

Esta dissertação tem por objetivo investigar a hipótese de que os Hedge Funds, com sua maneira agressiva de operar e de se alavancar nos mercados financeiros, seriam capazes de potencializar os ataques especulativQs so.fIidos por diversos países nos últimos anos. Como referencial teórico, foram apresentados os modelos maIS discutidos de CrIses cambiais de pnmeIra, segunda e terceira geração. Ainda para sustentar a conclusão de que os Hedge Funds potencializam os ataques especulativos, apresentamos o papel desempenhado pelos Hedge Funds nas recentes cnses cambiais como referencial prático. Esta dissertação está estruturada em três seções, além da Introdução, da Conclusão e da Bibliografia. A primeira apresenta a Indústria dos Hedge Funds e seus principais conceitos; a segunda apresenta alguns dos modelos de crises cambiais mais discutidos na literatura e os modelos de Calvo de 1999 e Corsetti et aI. (2000); e a terceira fala sobre as crises cambiais recentes e o papel desempenhado pelos Hedge Funds nestas crises.

Medidas de desempenho para hedge funds no Brasil com destaque para a medida Ômega

A avaliação de desempenho de fundos de investimentos é, tradicionalmente, realizada utilizando-se o Índice de Sharpe, que leva em consideração apenas os dois primeiros momentos da distribuição de retornos (média e variância), assumindo as premissas de normalidade da distribuição de retornos e função quadrática de utilidade do investidor. Entretanto, é sabido que uma função de utilidade quadrática é inconsistente com o comportamento do investidor e que as distribuições de retornos de determinados fundos, como os hedge funds, estão longe de serem uma distribuição normal. Keating e Shadwick (2002a, 2002b) introduziram uma nova medida denominada Ômega que incorpora todos os momentos da distribuição, e tem a vantagem de não ser necessário fazer premissas sobre a distribuição dos retornos nem da função de utilidade de um investidor avesso ao risco. O objetivo deste trabalho é verificar se esta medida Ômega tem um poder de previsibilidade maior que outras medidas de avaliação de desempenho, como o Índice de Sharpe e o Índice de Sortino. O estudo empírico indicou que a medida Ômega gera um ranqueamento, na maioria das vezes, relativamente diferente das outras medidas testadas. Apesar das carteiras formadas com base na medida Ômega terem gerado um retorno médio maior que o retorno médio das carteiras formadas pelas outras medidas em praticamente todos os testes, esta diferença entre as médias dos retornos só foi significativa em alguns casos. Mesmo assim, há uma leve indicação de que a medida Ômega é a mais apropriada para utilização do investidor ao fazer a avaliação de desempenho dos fundos de investimentos.

Participação e a governança nas organizações mutuais

As organizações mutuais, sejam ONGs, cooperativas, associações, fundos de pensão e clubes entre outros, são responsáveis por enormes movimentações financeiras, sociais, e políticas, porém, a governança desse tipo de instituição depende profundamente do envolvimento e participação efetiva dos seus participantes. O presente estudo tem como objetivo identificar quais são e como se comportam os mecanismos da participação na governança das organizações mutuais, frente à natureza das organizações. Inicialmente, é apresentada uma revisão dos conceitos de governança, organizações mutuais, participação e ação coletiva. Em seguida, baseado na abordagem das Normas de Sociais proposta por Elster (1989), é analisada a influência da natureza de três organizações mutuais frente às normas de cooperação praticadas por seus componentes, permitindo identificar que, de acordo com o perfil constitutivo da organização, as normas de cooperação que regem a participação na governança podem ser diferentes e intimamente ligadas ao perfil cooperativo dos seus participantes.