A new mechanism for anticipating price exuberance

It is very important for investors, market regulators, and policy makers to possess a trustworthy ex-ante tool capable of anticipating price exuberance events. This paper proposes a new statistical mechanism to predict speculative bubbles by inferring a significant probability of exuberance at least one step ahead of a bubble peak period. Contrary to other approaches, we combine asset pricing modeling and non-stationarity statistical analysis and use both in the context of adaptive learning to build a dynamic model specification. Monte Carlo simulations show that the ex-ante prediction is improved enormously by adding the estimated abnormal returns into the model. In some cases our mechanism predicts 100% of the last bubbles of the sample up to five periods before the peak. Furthermore, the mechanism is able to successfully anticipate the technological bubble observed in the 1990’s by estimating a probability greater than 90%, one month before the bubble peak. Thus, this new mechanism provides an advantage for investors interested in performing a very profitable “bubble surfing” strategy and for market regulators whose responsibility is to maintain market efficiency.info:eu-repo/semantics/publishedVersio

Irrigação do arroz de terras altas em função da porcentagem de cobertura do solo pela palhada, no sistema plantio direto.

Introdução; Coeficiente do tanque; Coeficiente de cultura; Controle de irrigação.bitstream/CNPAF/23535/1/circ_69.pd

As transformações quanto aos principais usos da floresta na comunidade Santa Maria, assentamento olho d'água II, município de Moju, estado do Pará.

As reflexões apresentadas foram resultantes de uma pesquisa realizada na comunidade Santa Maria, espacializada no Assentamento Olho D’Água II, município de Moju, Nordeste Paraense, durante os meses de maio e julho de 2008. O objetivo do artigo é analisar as transformações vivenciadas por um grupo de agricultores quanto ao uso da floresta, mais especificamente as associadas à obtenção de caças e a realização das roças, após a mudança da condição de uso comum (posseiros) para o uso privado (assentados) a partir da implantação do assentamento em 2002. A metodologia constou de abordagens qualitativas e quantitativas, tendo como principais procedimentos: revisão de literatura, entrevistas estruturadas e semiestruturadas, observações e levantamento de dados secundários. Os resultados apontam que ocorreram transformações importantes nas dinâmicas de uso dos recursos com intensificação do cultivo de roças e diminuição da obtenção de caças devido a grande dificuldade em obtê-las, em decorrência das novas condições de acesso privado à terra, como também, por causa do aumento demográfico cuja demanda por caça supera em muito a oferta dos animais, fato que impulsiona ainda mais a especialização no uso das roças que constituem-se na principal fonte de renda e alimento para a reprodução familiar

Semiclassical back reaction around a cosmic dislocation

The energy-momentum vacuum average of a conformally coupled massless scalar field vibrating around a cosmic dislocation (a cosmic string with a dislocation along its axis) is taken as source of the linearized semiclassical Einstein equations. The solution up to first order in the Planck constant is derived. Motion of a test particle is then discussed, showing that under certain circumstances a helical-like dragging effect, with no classical analogue around the cosmic dislocation, is induced by back reaction.Comment: Published version, 4 pages, no figures, REVTeX4 fil

Improving IT infrastructures representation: A UML profile

IT infrastructures are most times informally modeled. The resulting models are ambiguous to stakeholders, cannot be checked for validity, and therefore are unable to play their important role in design, deployment and maintenance activities. The main reason for such a poor state-of-the-art lies mainly in the absence of a modeling language capable of representing IT infrastructures at the required level of abstraction. Indeed, existing candidate languages are too abstract, as shown in this paper by reviewing their metamodels. The present paper mitigates this problem by proposing a UML profile to describe the semantics of an IT infrastructure.info:eu-repo/semantics/publishedVersio

Improving IT infrastructures representation: A UML profile

IT infrastructures are most times informally modeled. The resulting models are ambiguous to stakeholders, cannot be checked for validity, and therefore are unable to play their important role in design, deployment and maintenance activities. The main reason for such a poor state-of-the-art lies mainly in the absence of a modeling language capable of representing IT infrastructures at the required level of abstraction. Indeed, existing candidate languages are too abstract, as shown in this paper by reviewing their metamodels. The present paper mitigates this problem by proposing a UML profile to describe the semantics of an IT infrastructure.info:eu-repo/semantics/publishedVersio