Estrogênio melhora o desempenho mental

Estudos afirmam que o hormônio estrogênio pode aguçar o desempenho mental. Agora, os cientistas acreditam saber o por que. O estrogênio pode aumentar o número de conexões entre as células cerebrais, melhorando a comunicação no cérebro. A pesquisa foi apresentada no dia 17 de novembro no encontro Society for Neuroscience.

Copiar os efeitos do estrogênio no cérebro pode ajudar os tratamentos para o mal de Alzheimer e para a esquizofrenia, segundo os pesquisadores.

Trabalhos anteriores mostraram que o estrogênio poderia melhorar a memória e aumentar a precisão de pessoas e animais em provas e testes. Nesse novo trabalho, os pesquisadores da Northwestern University Feinberg School of Medicine trataram células cerebrais de ratos desenvolvidas em laboratório com um composto similar ao estrogênio. O composto ativou os receptores de estrogênio das células, desencadeando uma série de reações químicas, o que, por sua vez, causou um aumento no número de espinhas dendríticas (saliências semelhantes a pêlos na superfície das células que permitem a comunicação entre elas). Segundo os pesquisadores, essa ativação do receptor de estrogênio pode potencialmente aumentar a quantidade de informação que vai de uma célula para a outra.

Porém, o uso a longo prazo do estrogênio como terapia já se mostrou problemático. Em 2002, um estudo concluiu que mulheres que tomaram estrogênio para aliviar sintomas da menopausa tiveram um risco aumentado de câncer de mama, derrame e ataque cardíaco.

Por causa destes riscos, os pesquisadores têm procurado uma maneira de ativar os receptores de estrógeno sem o uso de estrogênio em si. Isso permitiria que os pacientes obtivessem os benefícios do estrogênio sem os efeitos colaterais. O composto do estudo é uma maneira de imitar os efeitos do estrogênio. Os pesquisadores ainda não sabem se há efeito colateral já que o estud foi realizado apenas com ratos. Assim, são necessários mais estudos para determinar se o mesmo efeito – o aumento de comunicação entre as células – ocorreria no cérebro dos seres humanos.

Fonte: LiveScience

Rir é o melhor remédio

Diploma Universitário?

Stephen Hawking

O cientista Stephen Hawking foi laureado com o prêmio mais lucrativo existente para as ciências: o Special Fundamental Physics Prize por “lifetime of achievements” (uma espécie de prêmio conjunto da obra do cientista) que vem acompanhado de US$ 3 milhões de dólares. Uma das exigências é a de que o ganhador dê ao menos uma palestra por ano, que será gravada e postada no site da fundação que ampara o prêmio.

Os pesquisadores do CERN (Centro Europeu para a Pesquisa Nuclear) também receberão a mesma quantia pela provável descoberta da partícula subatômica Bóson de Higgs.

Ainda será anunciada uma lista de candidatos ao prêmio em 2013, assim como prêmios de US$ 100.000 para trabalhos emergentes.

O prêmio é um de vários estabelecidos em julho por Yuri Milner, um físico russo que largou o doutorado (ele se autointitula “físico fracassado”) e ganhou bilhões de dólares investindo em mídias sociais e empresas como Twitter, Facebook e Groupon.

Os vencedores do prêmio foram selecionados por um comitê independente de físicos conhecidos. Acredita-se que pesquisadores mais novos que os do prêmio Nobel serão premiados, já que não é um pré-requisito a prova experimental do trabalho teórico.

The Guardian e The New York Times

Novo sistema WebQualis

A Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes) divulgou o novo sistema Webqualis na última sexta-feira (7 de dezembro).

Eu não gostei das alterações. Aparecem poucos resultados por páginas (deveria haver a opção de aumentar de 10 resultados para 50, por exemplo) e quando se exporta a lista completa só há a opção em pdf. Não achei a opção em Excel (não exauri a busca) que facilita filtrar as revistas por nome e estrato sem estarmos conectados, assim como escrever anotações nas células (como o tempo médio de avaliação).

Governança e Teoria da Agência

A introdução da responsabilidade limitada e a abertura do capital das empresas teve um impacto dramático na forma com que as companhias eram controladas. O sistema de mercado do Reino Unido e dos Estados Unidos, inter alia, é organizado de tal forma que os proprietários (que são essencialmente acionistas das empresas listadas) delegam o funcionamento da empresa à administração da entidade. Há uma separação da propriedade e do controle que leva ao notório “problema de agência”.

A teoria da agência identifica o relacionamento no qual uma parte, o principal, delega trabalho a uma segunda parte, o agente. O relacionamento de agência pode apresentar desvantagens em relação ao oportunismo ou interesse próprio do agente: por exemplo, o agente pode não atuar de acordo com os melhores interesses do principal, ou o agir apenas parcialmente de acordo com os interesses do principal.

Na teoria financeira há uma suposição de que o objetivo primário das empresas é maximizar a riqueza dos acionistas. Na prática isso não é necessariamente o caso. É verossímil que os administradores da empresa prefiram perseguir seus objetivos próprios, de forma a ganhar os maiores prêmios possíveis. Gerentes têm a probabilidade de apresentar uma tendência egoísta, o que pode resultar em uma propensão a focar em projetos e investimentos que resultem retornos em curto prazo (quando o pagamento dos gerentes é relacionado a essa variável) ao invés de maximizar a riqueza dos acionistas por meio de investimentos com a natureza em longo prazo.
No contexto das corporações e do controle das corporações, a teoria da agência vê os mecanismos de governança corporativa, especialmente o conselho diretivo, como sendo um dispositivo essencial de monitoramento que garante que problemas que surjam sobre o relacionamento principal-agente serão minimizados.

Grande parte da teoria da agência é relacionada ao contexto da separação do proprietário e do controle. Nesse contexto, os agentes são administradores e os principais são acionistas – essa é a relação de agência mais comumente citada no contexto da governança corporativa. Todavia, é conveniente ressaltar que a relação de agência pode envolver várias outras relações (empresa e credor, empregado e empregador).

“Corporate Governance” [MALLIN, CHRISTINE A. 3 ed. Oxford: Reino Unido, 2010]. “Corporate Governance and Accountability” [SOLOMON, J. 3. Ed. Wiley: Reino Unido, 2011].

Crise financeira sistêmica: 1873,1893,1907,1929 e 2007

Magnífico artigo de Carmen Reinhart e Kenneth Rogoff sobre a crise financeira de 2007. O melhor que já li.Os grifos são meus.

Five years after the onset of the 2007 subprime financial crisis, U.S. gross domestic product per capita remains below its initial level. Unemployment, though down from its peak, is still about 8 percent. Rather than the V- shaped recovery that is typical of most postwar recessions, this one has exhibited slow and halting growth.

This disappointing performance shouldn’t be surprising. We have presented evidence that recessions associated with systemic banking crises tend to be deep and protracted and that this pattern is evident across both history and countries. Subsequent academic research using different approaches and samples has found similar results.

Recently, however, a few op-ed writers have argued that, in fact, the U.S. is “different” and that international comparisons aren’t relevant because of profound institutional differences from one country to another. Some of these authors, including Kevin Hassett, Glenn Hubbard and John Taylor -- who are advisers to the Republican presidential nominee, Mitt Romney -- as well as Michael Bordo, who supports the candidate, have stressed that the U.S. is also “different” in that its recoveries from recessions associated with financial crises have been rapid and strong. Their interpretation is at least partly based on a 2012 study by Bordo and Joseph Haubrich, which examines the issue for the U.S. since 1880.

[...]This is far from the first time we have taken up the history of U.S. financial crises. Our 2009 book, “This Time Is Different: Eight Centuries of Financial Folly,” presented results of 224 historical banking crises from around the world, including pre-2007 banking crises in the U.S. Why is our interpretation of the data so different than those of these recent commentators? Is the U.S. different?

Part of the confusion may be attributed to a failure to distinguish systemic financial crises from more minor ones and from regular business cycles. A systemic financial crisis affects a large share of a country’s financial system. Such occurrences are quite distinct from events that clearly fall short of a full-blown systemic meltdown, and are referred to in the academic literature as “borderline” crises.

The distinction between a systemic and a borderline event is well established by widely accepted criteria long used by many scholars, and detailed in our 2009 book.

Indeed, in our initial published study on this topic, in 2008, we showed that systemic financial crises across advanced economies had far more serious economic consequences than borderline ones. Our paper, written nine months before the collapse of Lehman Brothers Holdings Inc. in September 2008, showed that by 2007, the U.S. already displayed many of the crucial recurring precursors of a systemic financial crisis: a real estate bubble, high levels of debt, chronically large current-account deficits and signs of slowing economic activity.

Today, there can be little doubt that the U.S. has experienced a systemic crisis -- in fact, its first since the Great Depression. Before that, notable systemic post-Civil War financial crises occurred in 1873, 1893 and 1907.

Defining Success

It is also important to define how a recovery is measured, and how success is defined. The recent op-eds focus on GDP growth immediately after the trough (usually four quarters). For a normal recession, the restoration of positive growth is typically a signal event. In a V-shaped recovery, the old peak level of GDP is quickly reached, and the economy returns to trend within a year or two.

Our book examined both levels and rates of change of per capita GDP; recovery is defined by the time it takes for per capita GDP to return to its pre-crisis peak level. For post- World War II systemic crises, it took about four and a half years to regain lost ground; in 14 Great Depression episodes around the world (including the U.S.) it took 10 years on average. A focus on levels, rather than percentages, is a more robust way to capture the trajectory of an economy where the recovery is more U- or L-shaped than V-shaped.

It also is a way to avoid exaggerating the strength of the recovery when a deep recession is followed by a large cumulative decline in the level GDP. An 8 percent decline followed by an 8 percent increase doesn’t bring the economy back to its starting point.

[...]Working with long historical series, we have stressed per- capita measures because U.S. population growth has fallen from 2 percent a year in the late 1800s to less than 1 percent in more recent times. Put differently, in the early 1900s, a year with 2 percent real GDP growth left the average person’s income unchanged; in the modern context, 2 percent annual GDP growth means an increase of slightly more than 1 percent in real income per person. The impact of cumulative population growth even within an individual crisis episode is significant, as the recovery process usually spans four to 10 years.

1907 Panic

Take the Panic of 1907, which fits the standard criteria of a systemic crisis (and one with a global dimension at that). We certainly would count that one. The narrative in the Bordo- Haubrich paper emphasizes that “the 1907-1908 recession was followed by vigorous recovery.” Yet, as we show below, the level of real GDP per capita in the U.S. didn’t return to its pre- crisis peak of 1906 until 1912. Is that a vigorous recovery? The unemployment rate (which we routinely include in our comparisons but the Bordo-Haubrich study doesn’t consider) was 1.7 percent in 1906, climbed to 8 percent in 1908, and didn’t return to the pre-crisis low until 1918.

The aftermath of the systemic banking crisis of 1893 is worse than the period after the 1907 episode, and the Depression of the 1930s is worse still. According to our 2009 metrics, the aftermath of the most recent U.S. financial crisis has been quite typical of systemic financial crises around the globe in the postwar era. If one really wants to focus just on U.S. systemic financial crises, then the recent recovery looks positively brisk.

We examine four systemic financial crises the U.S. has experienced since 1870: 1873 (called the Great Depression until the 1930s), 1893, the Panic of 1907 and the Great Depression.

Given that all of these crises predate the creation of deposit insurance in 1933, and that three of the four events predate the establishment of a U.S. central bank, one could legitimately quibble with the claim that the relevant institutions are more comparable across centuries in the U.S. than across advanced countries over the past 30 years. We would argue that our 2009 international postwar benchmarks, along with comparisons for the recent crisis, are more relevant.

Nonetheless, the comparison across systemic U.S. financial crises doesn’t support the view that:

-- the U.S. recoveries from pre-World War II systemic crises were any swifter than the general cross-country pattern;

-- in the aftermath of the 2007 crisis, the U.S. has performed worse than in previous systemic crises, In fact, so far, it has performed better in terms of output per capita and unemployment. This is true even if one excludes the Great Depression.

The Evidence

The reader may wish to note that our comparisons relate to the period dating from the onset of the crisis, and don’t delineate between the “recession” period and the “recovery” period.

We have explained elsewhere why this distinction is somewhat meaningless in the aftermath of a financial crisis, as false dawns make it very difficult to detect the start of a lasting recovery in real time. That is why we have consistently argued that the popular term “Great Recession” is something of a misnomer for the current episode, which we have argued would be better thought of as “the Second Great Contraction” (after Milton Friedman and Anna Schwartz’s characterization of the Great Depression as the Great Contraction).

[...]Figure 1  compares the still unfolding (2007) financial crisis with U.S. systemic financial crises of 1873, 1893, 1907 and 1929. As the figure illustrates, the initial contraction in per-capita GDP is smaller for the recent crisis than in the earlier ones (even when the Great Depression of the 1930s is excluded). Five years later, the current level of per- capita GDP, relative to baseline, is higher than the corresponding five-crisis average that includes the 1930s. The recovery of per-capita GDP after 2007 is also slightly stronger than the average for the systemic crises of 1873, 1893 and 1907. Although not as famous as the Great Depression, the depression of the 1890s was dismal; in 1896, real per-capita GDP was still 6 percent below its pre-crisis level of 1892.

Peak GDP

So how many years did it take for per-capita GDP to return to its peak at the onset of the crisis? For the 1873 and 1893 (peak is 1892) crises, it was five years; for the Panic of 1907 (peak is 1906), it was six years; for the Depression, it took 11 years. In output per capita timelines, at least, it is difficult to argue that “the U.S. is different.” It can hardly be said to have enjoyed vigorous output per capita recoveries from past systemic financial crises.

The notion that the U.S. exhibits rapid recovery from systemic financial crises doesn’t emerge from the unemployment data, either. That data only begin in 1890, eliminating the 1873 crisis from the pool. The aftermaths of the remaining four crises are shown in Figure 2.

[...]The pattern during the Great Depression of the 1930s is off the charts (Barry Eichengreen and Kevin H. O’Rourke’s 2010 study is a must-read on this comparison). These historical U.S. episodes are in line with the 2010 findings of Carmen and Vincent Reinhart, who examine severe/systemic financial crises in both advanced economies and emerging markets in the decade after World War II. They document that in 10 of 15 episodes the unemployment rate had not returned to its pre-crisis level in the decade after the crisis. For the 1893 crisis and the 1929 Depression, it was 14 years; for 1907, it took 12 years for the unemployment rate to return to its pre-crisis level.

Recurring Features

Although no two crises are identical, we have found that there are some recurring features that cut across time and national borders. Common patterns in the nature of the long boom-bust cycles in debt and their relationship to economic activity emerge as a common thread across very diverse institutional settings.

The most recent U.S. crisis appears to fit the more general pattern of a recovery from severe financial crisis that is more protracted than with a normal recession or milder forms of financial distress. There is certainly little evidence to suggest that this time was worse. Indeed, if one compares U.S. output per capita and employment performance with those of other countries that suffered systemic financial crises in 2007-08, the U.S. performance is better than average.

[...]It is not our intention to closely analyze policy responses that may take years of study to sort out. Rather, our aim is to dismiss the misconception that the U.S. is somehow different. The latest financial crisis, yet again, proved it is not.

Fonte: Sorry, U.S. Recoveries Really Aren’t Different

By Carmen M. Reinhart & Kenneth S. Rogoff 2012-10-15T22:30:29Z(Carmen M. Reinhart is Minos A. Zombanakis professor of the international financial system atHarvard University’s Kennedy School of Government. Kenneth S. Rogoff is a professor of public policy and economics at Harvard University. They are co-authors of “This Time is Different: Eight Centuries of Financial Folly.” The opinions expressed are their own.)

Recorde no Xadrez

Com a vitória no torneio de Londres, o gênio norueguês Magnus Carlsen atingiu um rating de 2862. Trata-se do melhor desempenho de um enxadrista desde que o sistema de pontuação foi criado há mais de 40 anos. O valor do rating ainda não é oficial já que a federação internacional só irá divulgar um novo rating no início de janeiro. O recorde anterior era de Kasparov, com 2851.

No torneio de Londres, Carlsen terminou em primeiro, com 18 pontos: 5 vitórias e 3 empates (neste torneio a vitória valia 3 pontos e o empate 1).

O gráfico a seguir mostra o desempenho dele em relação aos demais jogadores: