2,918 research outputs found
Atributos corporativos e concentração acionária no Brasil
Este artigo enfoca os possíveis determinantes da concentração do direito de voto e do direito sobre o fluxo de caixa por parte dos acionistas controladores das companhias abertas brasileiras. A análise investiga se variáveis endógenas das firmas e setoriais fazem com que algumas empresas tenham estrutura de propriedade mais concentrada do que outras submetidas ao mesmo ambiente contratual. Ao se aplicarem testes empíricos a um painel com 161 empresas entre os anos de 1998 e 2002, as variáveis testadas como possíveis determinantes não parecem infl uenciar a concentração acionária dos controladores das empresas analisadas. Os resultados oferecem evidência em favor da hipótese de influência da exogeneidade da estrutura de propriedade sobre o desempenho corporativo, adotada em trabalhos recentes.This article focuses on the possible determinants of the concentration of the right to vote and the rights over cash-flow of the controlling shareholders of publicly-quoted Brazilian companies. The analysis investigates if endogenous variables of firms and sectors mean that some companies have a more concentrated corporate structure than others that undergo the same contractual environment. When empirical tests were applied to a panel of 161 companies between 1998 and 2002, the variables that were tested as possible determinants seem not to have an influence on the shareholder concentration of the owners of the companies that were analyzed. The results offer evidence in favor of the hypothesis of the influence of the exogeneity of the ownership structure on corporate performance, which has been used in recent work
Facing the regulators: non-compliance with detailed mandatory compensation disclosure in Brazil
A preliminary court injunction based on alleged personal security risks to managers and directors gave Brazilian public companies the option of non-compliance with the most sensitive part of newly mandated compensation disclosure rules. We find, however, no association between state-level crime data and non-compliance, which is possibly motivated by agency conflicts. Non-compliers tend to present lower corporate governance (CG) quality, higher ownership concentration, larger total assets, and less profitability. State and foreign owned companies are significantly less likely non-compliers. Shareholders correctly anticipated that lower CG quality firms were more likely to exercise their non-compliance option, but may have been negatively surprised when some higher CG quality firms did not comply.Indisponíve
Exogenous nitric oxide improves sugarcane growth and photosynthesis under water deficit
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Nitric oxide (NO)-mediated redox signaling plays a role in alleviating the negative impact of water stress in sugarcane plants by improving root growth and photosynthesis. Drought is an environmental limitation affecting sugarcane growth and yield. The redox-active molecule nitric oxide (NO) is known to modulate plant responses to stressful conditions. NO may react with glutathione (GSH) to form S-nitrosoglutathione (GSNO), which is considered the main reservoir of NO in cells. Here, we investigate the role of NO in alleviating the effects of water deficit on growth and photosynthesis of sugarcane plants. Well-hydrated plants were compared to plants under drought and sprayed with mock (water) or GSNO at concentrations ranging from 10 to 1000 mu M. Leaf GSNO sprayed plants showed significant improvement of relative water content and leaf and root dry matter under drought compared to mock-sprayed plants. Additionally, plants sprayed with GSNO (a parts per thousand yen 100 mu M) showed higher leaf gas exchange and photochemical activity as compared to mock-sprayed plants under water deficit and after rehydration. Surprisingly, a raise in the total S-nitrosothiols content was observed in leaves sprayed with GSH or GSNO, suggesting a long-term role of NO-mediated responses to water deficit. Experiments with leaf discs fumigated with NO gas also suggested a role of NO in drought tolerance of sugarcane plants. Overall, our data indicate that the NO-mediated redox signaling plays a role in alleviating the negative effects of water stress in sugarcane plants by protecting the photosynthetic apparatus and improving shoot and root growth.2441181190Sao Paulo Research Foundation (FAPESP, Brazil) [2008/57519-2]National Council for Scientific and Technological Development (CNPq, Brazil)[2012/19167-0][2015/00393-8]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Endogeneity in panel data regressions: methodological guidance for corporate finance researchers
Purpose –To describe the use of specific lags (and/or temporal differences) of the original regressors as instrumental variables in a succinct and practical way, showing, by means of a theoretical discussion illustrated by an original simulation exercise, how combining these with adequate modeling of firm and time fixed effects can address not only the dynamic endogeneity problem, but also those derived from the presence of omitted variables, measurement errors, and simultaneity between dependent and independent variables.
Design/methodology/approach – Monte Carlo simulation
Findings – The traditional OLS, RE, and FE estimators may be inconsistent in the presence of endogeneity problems that are quite plausible in the context of corporate finance. On the other hand, the estimation methods for panel data based on GMM that use assumptions of sequential exogeneity of the regressors present alternatives that are capable of effectively overcoming all the problems listed (provided these assumptions are valid) even if the researcher does not have good instrumental variables that are external to the model
Originality/value –The paper discusses and illustrates a greater number of endogeneity problems, showing how they are addressed by different estimators for panel data, using less technical and more accessible language for researchers not yet initiated in the intricacies of estimating dynamic models for panel data
Finanças comportamentais: uma introdução
A subject often debated in Finance is the validity of assumptions regarding traditional theories, especially in relation to the rationality of economic agents. Studies endeavoring to improve theoretical models have incorporated behavioral aspects previously disregarded thereby creating the new and promising field of behavioral finance. The remarkable growth of this unorthodox approach has been spurred by attempts to explain phenomena in the financial markets which are incompatible with traditional model forecasts. A brief introduction to the concepts of behavioral finance was presented with comments on pioneer applications that incorporated two frequent examples of cognitive biases, namely optimism and excessive confidence, for the purpose of building a new theoretical paradigm.Dentre as principais questões que vêm sendo debatidas em Finanças está a validade das premissas assumidas por suas teorias mais tradicionais, em particular a da racionalidade dos agentes econômicos. Nesse contexto, surgiram diversos trabalhos com o objetivo de aprimorar os modelos teóricos dominantes, incorporando aspectos comportamentais antes desconsiderados. Essas linhas de pesquisa deram origem a um novo e promissor campo de estudo denominado Finanças Comportamentais. O notável crescimento dessa abordagem não ortodoxa tem sido motivado, em especial, pela tentativa de explicação satisfatória de uma gama de fenômenos regularmente observados nos mercados financeiros e incompatíveis com as predições dos modelos tradicionais. Este ensaio apresenta uma introdução sucinta aos conceitos fundamentais da área de Finanças Comportamentais e comenta duas aplicações pioneiras que incorporam dois dos vieses cognitivos mais bem documentados - otimismo e confiança excessiva
A Model of DENV-3 Infection That Recapitulates Severe Disease and Highlights the Importance of IFN-γ in Host Resistance to Infection
There are few animal models of dengue infection, especially in immunocompetent mice. Here, we describe alterations found in adult immunocompetent mice inoculated with an adapted Dengue virus (DENV-3) strain. Infection of mice with the adapted DENV-3 caused inoculum-dependent lethality that was preceded by several hematological and biochemical changes and increased virus dissemination, features consistent with severe disease manifestation in humans. IFN-γ expression increased after DENV-3 infection of WT mice and this was preceded by increase in expression of IL-12 and IL-18. In DENV-3-inoculated IFN-γ−/− mice, there was enhanced lethality, which was preceded by severe disease manifestation and virus replication. Lack of IFN-γ production was associated with diminished NO-synthase 2 (NOS2) expression and higher susceptibility of NOS2−/− mice to DENV-3 infection. Therefore, mechanisms of protection to DENV-3 infection rely on IFN-γ-NOS2-NO-dependent control of viral replication and of disease severity, a pathway showed to be relevant for resistance to DENV infection in other experimental and clinical settings. Thus, the model of DENV-3 infection in immunocompetent mice described here represents a significant advance in animal models of severe dengue disease and may provide an important tool to the elucidation of immunopathogenesis of disease and of protective mechanisms associated with infection
The BLue Amazon Brain (BLAB): A Modular Architecture of Services about the Brazilian Maritime Territory
We describe the first steps in the development of an artificial agent focused
on the Brazilian maritime territory, a large region within the South Atlantic
also known as the Blue Amazon. The "BLue Amazon Brain" (BLAB) integrates a
number of services aimed at disseminating information about this region and its
importance, functioning as a tool for environmental awareness. The main service
provided by BLAB is a conversational facility that deals with complex questions
about the Blue Amazon, called BLAB-Chat; its central component is a controller
that manages several task-oriented natural language processing modules (e.g.,
question answering and summarizer systems). These modules have access to an
internal data lake as well as to third-party databases. A news reporter
(BLAB-Reporter) and a purposely-developed wiki (BLAB-Wiki) are also part of the
BLAB service architecture. In this paper, we describe our current version of
BLAB's architecture (interface, backend, web services, NLP modules, and
resources) and comment on the challenges we have faced so far, such as the lack
of training data and the scattered state of domain information. Solving these
issues presents a considerable challenge in the development of artificial
intelligence for technical domains
Utilização de eletroquimioterapia para carcinoma de células escamosas tegumentar em felino
Transplante pulmonar no tratamento de pneumopatias / Lung transplantation in the treatment of pneumopathies
O transplante pulmonar é uma opção terapêutica com alto potencial para o tratamento de diversas pneumopatias avançadas, levando aoreceptor sobrevida e uma melhor qualidade de vida. No entanto, diferente dos outros órgãos sólidos, no transplante pulmonar vemos um cenárioonde existe umacarência na oferta de órgão doador e uma alta demanda para o transplante. Essa carência ocorre pela falta de doadores adequados nos critérios de seleção, pois devido às agressões ao pulmão ocasionadas pela morte encefálica e aos cuidados na UTI, leva a uma não viabilidade da doação do órgão e como consequência um aumento desproporcional na fila de espera.Ademais, existem propostas tecnológicas para aumentar a oferta de pulmões. A perfusão pulmonar ex vivo,é considerada uma proposta com bastante perspectiva por conseguir recuperar alguns pulmões que inicialmente eram descartados.É fundamental que a ciência continue demostrando constante evolução nas diversas etapas do transplante pulmonar, como aprimoramento nos métodos, no suporte pré, peri e pós operatório, no aumento da oferta pulmonar, com objetivo de aumentar a sobrevida e diminuir a carência de órgão doador. Além disso, é necessário o conhecimento dos critérios de indicação, contraindicação e do manejo para alcançar melhor resultados nessa opção terapêutica para pneumopatias avançadas.O transplante pulmonar é uma opção terapêutica com alto potencial para o tratamento de diversas pneumopatias avançadas, levando ao receptor sobrevida e uma melhor qualidade de vida. No entanto, diferente dos outros órgãos sólidos, no transplante pulmonar vemos um cenário onde existe uma carência na oferta de órgão doador e uma alta demanda para o transplante. Essa carência ocorre pela falta de doadores adequados nos critérios de seleção, pois devido às agressões ao pulmão ocasionadas pela morte encefálica e aos cuidados na UTI, leva a uma não viabilidade da doação do órgão e como consequência um aumento desproporcional na fila de espera. Ademais, existem propostas tecnológicas para aumentar a oferta de pulmões. A perfusão pulmonar ex vivo, é considerada uma proposta com bastante perspectiva por conseguir recuperar alguns pulmões que inicialmente eram descartados. É fundamental que a ciência continue demostrando constante evolução nas diversas etapas do transplante pulmonar, como aprimoramento nos métodos, no suporte pré, peri e pós operatório, no aumento da oferta pulmonar, com objetivo de aumentar a sobrevida e diminuir a carência de órgão doador. Além disso, é necessário o conhecimento dos critérios de indicação, contraindicação e do manejo para alcançar melhor resultados nessa opção terapêutica para pneumopatias avançada
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