939 resultados para Pointwise constraints


Relevância:

10.00% 10.00%

Publicador:

Resumo:

1. Between 1988 and 2001, we studied social relationships in the superb fairy-wren Malurus cyaneus (Latham), a cooperative breeder with male helpers in which extra-group fertilizations are more common than within-pair fertilizations. 2. Unlike other fairy-wren species, females never bred on their natal territory. First-year females dispersed either directly from their natal territory to a breeding vacancy or to a foreign 'staging-post' territory where they spent their first winter as a subordinate. Females dispersing to a foreign territory settled in larger groups. Females on foreign territories inherited the territory if the dominant female died, and were sometimes able to split the territory into two by pairing with a helper male. However, most dispersed again to obtain a vacancy. 3. Females dispersing from a staging post usually gained a neighbouring vacancy, but females gaining a vacancy directly from their natal territory travelled further, perhaps to avoid pairing or mating with related males. 4. Females frequently divorced their partner, although the majority of relationships were terminated by the death of one of the pair. If death did not intervene, one-third of pairings were terminated by female-initiated divorce within 1000 days. 5. Three divorce syndromes were recognized. First, females that failed to obtain a preferred territory moved to territories with more helpers. Secondly, females that became paired to their sons when their partner died usually divorced away from them. Thirdly, females that have been in a long relationship divorce once a son has gained the senior helper position. 6. Dispersal to avoid pairing with sons is consistent with incest avoidance. However, there may be two additional benefits. Mothers do not mate with their sons, so dispersal by the mother liberates her sons to compete for within-group matings. Further, divorcing once their son has become a breeder or a senior helper allows the female to start sons in a queue for dominance on another territory. Females that do not take this option face constraints on their ability to recruit more sons into the local neighbourhood.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

New Zealand has a good Neogene plant fossil record. During the Miocene it was without high topography and it was highly maritime, meaning that its climate, and the resulting vegetation, would be controlled dominantly by zonal climate conditions. Its vegetation record during this time suggests the climate passed from an ever-wet and cool but frostless phase in the Early Miocene in which Nothofagus subgenus Brassospora was prominent. Then it became seasonally dry, with vegetation in which palms and Eucalyptus were prominent and fires were frequent, and in the mid-Miocene, it developed a dry-climate vegetation dominated by Casuarinaceae. These changes are reflected in a sedimentological change from acidic to alkaline chemistry and the appearance of regular charcoal in the record. The vegetation then changed again to include a prominent herb component including Chenopodiaceae and Asteraceae. Sphagnum became prominent, and Nothofagus returned, but mainly as the subgenus Fuscospora (presently restricted to temperate climates). This is interpreted as a return to a generally wet, but now cold climate, in which outbreaks of cold polar air and frost were frequent. The transient drying out of a small maritime island and the accompanying vegetation/climate sequence could be explained by a higher frequency of the Sub-Tropical High Pressure (STHP) cells (the descending limbs of the Hadley cells) over New Zealand during the Miocene. This may have resulted from an increased frequency of 'blocking', a synoptic situation which occurs in the region today. An alternative hypothesis, that the global STHP belt lay at a significantly higher latitude in the early Neogene (perhaps 55degreesS) than today (about 30degreesS), is considered less likely because of physical constraints on STHP belt latitude. In either case, the difference between the early Neogene and present situation may have been a response to an increased polar-equatorial temperature gradient. This contrasts with current climate models for the geological past in which the latitude of the High Pressure belt impact is held invariant though geological time. (C) 2003 Elsevier Science B.V. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BP Refinery (Bulwer Island) Ltd (BP) located on the eastern Australian coast is currently undergoing a major expansion as a part of the Queensland Clean Fuels Project. The associated wastewater treatment plant upgrade will provide a better quality of treated effluent than is currently possible with the existing infrastructure, and which will be of a sufficiently high standard to meet not only the requirements of imposed environmental legislation but also BP's environmental objectives. A number of challenges were faced when considering the upgrade, particularly; cost constraints and limited plot space, highly variable wastewater, toxicity issues, and limited available hydraulic head. Sequencing Batch Reactor (SBR) Technology was chosen for the lagoon upgrade based on the following; SBR technology allowed a retro-fit of the existing earthen lagoon without the need for any additional substantial concrete structures, a dual lagoon system allowed partial treatment of wastewaters during construction, SBRs give substantial process flexibility, SBRs have the ability to easily modify process parameters without any physical modifications, and significant cost benefits. This paper presents the background to this application, an outline of laboratory studies carried out on the wastewater and details the full scale design issues and methods for providing a cost effective, efficient treatment system using the existing lagoon system.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

For ground penetrating radar (GPR), smaller antennas would provide considerable practical advantages. Some of which are: portability; ease of use; and higher spatial sampling. A theoretical comparison of the fundamental limits of a small electric field antenna and a small magnetic field antenna shows that the minimum Q constraints are identical. Furthermore, it is shown that only the small magnetic loop antenna can be constructed to approach, arbitrarily closely, the fundamental minimum Q limit. This is achieved with the addition of a high permeability material which reduces energy stored in the magnetic fields. This is of special interest to some GPR applications. For example, applications requiring synthetic aperture data collection would benefit from the increased spatial sampling offered by electrically smaller antennas. Low frequency applications may also benefit, in terms of reduced antenna dimensions, by the use of electrically small antennas. Under these circumstances, a magnetic type antenna should be considered in preference to the typical electric field antenna. Numerical modeling data supports this assertion.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Electromagnetic articulography (EMA) was used to investigate how tongue movement characteristics (i.e., velocity, acceleration, duration, distance) change with. or indeed affect, increased rates of speech. Eight young adult males repeated /ta/ and /ka/ syllables first at a moderate rate that had been modelled at three syllables per second, and then 'as fast as possible'. Distance travelled by the tongue appeared to be the principal lingual kinematic feature manipulated by the group of speakers in producing increased syllable repetition rates, with velocity found to increase, decrease or remain unchanged. Acceleration remained unchanged, except in the case of increased velocity. One participant formed an exception in terms of manipulating distance by exhibiting marginally increased lingual velocities rather than distance changes. This preliminary study serves to direct future EMA-based studies of speech rate control as to the speech tasks that should be employed and the possible underlying anatomical and acoustic bases or constraints that could possibly influence the kinematic strategies employed to increase speech rate.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper conducts a dynamic stability analysis of symmetrically laminated FGM rectangular plates with general out-of-plane supporting conditions, subjected to a uniaxial periodic in-plane load and undergoing uniform temperature change. Theoretical formulations are based on Reddy's third-order shear deformation plate theory, and account for the temperature dependence of material properties. A semi-analytical Galerkin-differential quadrature approach is employed to convert the governing equations into a linear system of Mathieu-Hill equations from which the boundary points on the unstable regions are determined by Bolotin's method. Free vibration and bifurcation buckling are also discussed as subset problems. Numerical results are presented in both dimensionless tabular and graphical forms for laminated plates with FGM layers made of silicon nitride and stainless steel. The influences of various parameters such as material composition, layer thickness ratio, temperature change, static load level, boundary constraints on the dynamic stability, buckling and vibration frequencies are examined in detail through parametric studies.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Over the past decade or so, there has been increasing demand for greater clarity about the major causes of disease and injury, how these differentially affect populations, and how they are changing. In part, this demand has been motivated by resource constraints and a realisation that better health is possible with more informed allocation of resources. At the same time, there has been a change in the way population health and its determinants are quantified, with a much closer integration of the quantitative population sciences (such as epidemiology, demography and health economics) to strengthen and broaden the evidence base for healthcare policy.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A necessidade de viabilizar investimentos p??blicos em um contexto de restri????o fiscal impulsionou governos de diversos pa??ses a buscar na parceria com o setor privado a alternativa para a realiza????o de obras e servi??os p??blicos. A experi??ncia paradigm??tica do Reino Unido em programas de parceria p??blico-privada (PPP) norteou a implanta????o de iniciativas semelhantes mundo afora. No Brasil, a aprova????o, em dezembro de 2004, da lei que disciplina as normas para contrata????o de PPP deu in??cio a um processo que passar?? pela defini????o dos projetos priorit??rios e que culminar?? na consolida????o das parcerias como mais um instrumento para a viabiliza????o de obras e servi??os p??blicos de que o pa??s necessita. Esse artigo tem por objetivo elucidar o modelo brasileiro de parcerias p??blico-privadas. Ap??s uma contextualiza????o inicial, s??o discutidos os fundamentos que balizam a implanta????o de um programa de PPP e apresentadas algumas caracter??sticas gerais dos contratos. Por fim, s??o expostos os pontos centrais da lei brasileira.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

As sociedades estatais s??o importantes organiza????es societ??rias, que podem servir ao administrador p??blico para a realiza????o de atividades econ??micas que configurem relevante interesse coletivo ou motivo de seguran??a nacional. Com a finalidade de adequarem-se aos limites de investimento p??blico e com vistas ao cumprimento do princ??pio da efici??ncia, elas podem utilizar-se de mecanismos societ??rios e contratuais de gest??o disponibilizados a empresas, sejam elas estatais ou privadas. Os movimentos societ??rios, os mecanismos de controle e partilha de controle e a ado????o das pr??ticas de governan??a corporativa s??o alternativas jur??dicas disponibilizadas aos administradores das empresas estatais. A an??lise do caso da Companhia Paranaense de Energia El??trica (Copel) ?? realizada no artigo com o prop??sito de auxiliar na visualiza????o da aplica????o de tais institutos.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Os ??rg??os da Administra????o P??blica Federal (APF) ter??o maior ??xito no alcance de seus objetivos estrat??gicos, investindo na implanta????o de um modelo de gest??o estrat??gica, adaptado para o ambiente de governo, mantendo o alinhamento estrat??gico com os ??rg??os normativos e de controle. Este artigo tem como objetivo apresentar um modelo de gest??o estrat??gica, adaptado a partir das perspectivas do Balanced Scorecard (BSC) desenvolvido pelos professores da Harvard Business School, Robert Kaplan e David Norton, em 1992, para ser utilizado pelos ??rg??os da APF; tal modelo mant??m um alinhamento estrat??gico organizacional com as recomenda????es do Tribunal de Contas da Uni??o (TCU). O modelo ir?? permitir a gest??o estrat??gica a partir da identifica????o dos objetivos estrat??gicos, metas, indicadores e a????es referentes ??s perspectivas do Balanced Scorecard, o que permitir?? o equil??brio entre os indicadores de efici??ncia no acompanhamento das metas de cada ??rg??o da APF, colaborando para uma gest??o estrat??gica integrada, que venha a modernizar a gest??o p??blica, agilizando as tomadas de decis??es e a troca de informa????es.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The synthesis of helium in the early Universe depends on many input parameters, including the value of the gravitational coupling during the period when the nucleosynthesis takes place. We compute the primordial abundance of helium as function of the gravitational coupling, using a semi-analytical method, in order to track the influence of G in the primordial nucleosynthesis. To be specific, we construct a cosmological model with varying G, using the Brans-Dicke theory. The greater the value of G at nucleosynthesis period, the greater the predicted abundance of helium. Using the observational data for the abundance of primordial helium, constraints for the time variation of G are established.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

As mudanças institucionais e regulatórias inseridas principalmente no setor de infraestrutura, em particular no setor de energia, passaram a ser um novo ponto de governança para o Estado a partir de meados da década de 1990. Naquele formato inicial, ficou claro um planejamento inadequado, uma vez que as privatizações de empresas do setor de energia ocorreram antes da criação da Agência Nacional de Energia Elétrica (ANEEL). Esse ponto, segundo os principais autores foi decisivo e pontual para que, nos primeiros anos, o processo regulatório não ter atendido as necessidades dos agentes envolvidos (Estado, empresa e cidadão). Esta situação culminou com uma forte crise no setor, bem como no racionamento de energia ocorrido no início do Século XXI. Essa situação levou a um outro período de reforma, instalado em 2004. O ponto principal desse trabalho esta fundamentando em apresentar algumas questões ligadas aos desafios da ANEEL, sendo esta sedimentada nos processos de aprendizado e conhecimento, porém não esquecendo de abordar os pontos fundamentais e impeditivos para que a plena eficiência seja alcançada. Ao longo desse estudo, podemos analisar que os resultados alcançados pela ANEEL são em parte sólidos, porém fatores como: dificuldades em retenção de pessoas no corpo da agência, restrições orçamentárias, riscos constantes de captura, aliado ao processo de assimetria de informação, bem como a convivência com o misto de empresas públicas e privadas, são fatores que aumentam as incertezas no ambiente e no processo regulatório, contribuindo, ainda que indiretamente, para que os investimentos não sejam aplicados de acordo com o planejado, conseqüentemente, toda essa condição tem afetado os resultados e o equilíbrio do setor de energia.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Utilizar robôs autônomos capazes de planejar o seu caminho é um desafio que atrai vários pesquisadores na área de navegação de robôs. Neste contexto, este trabalho tem como objetivo implementar um algoritmo PSO híbrido para o planejamento de caminhos em ambientes estáticos para veículos holonômicos e não holonômicos. O algoritmo proposto possui duas fases: a primeira utiliza o algoritmo A* para encontrar uma trajetória inicial viável que o algoritmo PSO otimiza na segunda fase. Por fim, uma fase de pós planejamento pode ser aplicada no caminho a fim de adaptá-lo às restrições cinemáticas do veículo não holonômico. O modelo Ackerman foi considerado para os experimentos. O ambiente de simulação de robótica CARMEN (Carnegie Mellon Robot Navigation Toolkit) foi utilizado para realização de todos os experimentos computacionais considerando cinco instâncias de mapas geradas artificialmente com obstáculos. O desempenho do algoritmo desenvolvido, A*PSO, foi comparado com os algoritmos A*, PSO convencional e A* Estado Híbrido. A análise dos resultados indicou que o algoritmo A*PSO híbrido desenvolvido superou em qualidade de solução o PSO convencional. Apesar de ter encontrado melhores soluções em 40% das instâncias quando comparado com o A*, o A*PSO apresentou trajetórias com menos pontos de guinada. Investigando os resultados obtidos para o modelo não holonômico, o A*PSO obteve caminhos maiores entretanto mais suaves e seguros.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A demanda por água do setor agrícola vem crescendo a cada ano, bem como o aperfeiçoamento do manejo da irrigação. Ainda assim, em locais onde a água encontra-se escassa, os conflitos entre usos e usuários devido a disputas para acesso à água tendem a se intensificar. Na maioria das vezes esse problema está relacionado à ausência de cobertura florestal, levando, por vezes, a problemas socioambientais. Nesse contexto, a pesquisa buscou avaliar o impacto da implantação de sistemas agroflorestais (SAF’s) irrigados na condição hídrica local (de escassez), estabelecendo-se estratégias que os torne atrativos ambientalsocial- e economicamente. Assim, por meio de simulação computacional, alternativas de consórcios agroflorestais foram avaliadas, tomando-se como referência uma região piloto, típica da agricultura espírito-santense, constituída por pequenas propriedades agrícolas de base familiar, inseridas parcialmente em APPs. As espécies banana, pupunha e goiaba foram selecionadas para compor os cenários agroflorestais. Os resultados da pesquisa mostram que os SAF’s irrigados são uma alternativa no sentido de minimizar os conflitos por demandas de água em regiões de escassez hídrica, com a redução de tais demandas o comprometimento de rendimentos financeiros. Além disso, os SAF’s são alternativas para diversificação da renda e para tentar controlar a sazonalidade dos preços de mercado.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Direito, Programa de Pós-Graduação em Direito, 2016.