903 resultados para Algebraic path formulation
Resumo:
Numa escola que se encontra em transformação no sentido de se adaptar aos contextos sociais, culturais e políticos que a rodeiam, cabe aos professores serem agentes ativos na definição do caminho a percorrer, visando o aumento da qualidade educativa a proporcionar aos nossos jovens. O questionamento inerente à reflexão sobre o percurso profissional levou à identificação da situação problema e à formulação daquela que é a questão de partida deste trabalho: Como pode a supervisão pedagógica promover a troca de experiências e o trabalho colaborativo entre os docentes de Matemática e de Ciências Físico Químicas? Para dar resposta a esta questão, elaborámos o enquadramento teórico, orientado pelas palavras-chave e com recurso a autores de referência, no qual pretendemos salientar as principais investigações que conferem suporte às temáticas subjacentes: Cultura profissional docente, Supervisão pedagógica, Gestão curricular. Como o objetivo geral do trabalho de projeto é conceber um projeto de supervisão pedagógica que promova a troca de experiências e o trabalho colaborativo entre os professores de Matemática e de Ciências Físico Químicas, a terceira parte foi estruturada com base nos princípios subjacentes à metodologia de projeto. Recolhemos opiniões através de Inquéritos por Questionário, aplicados a todos os professores dos grupos disciplinares de Matemática e de Ciências Físico-Químicas. A análise dos questionários permitiu constatar que o que é prescrito na literatura especializada não parece ser posto em prática, verificando-se incongruências entre o que deve ser feito e o que é levado a cabo na prática, o que nos leva a salientar a necessidade de formação em supervisão e mais concretamente em trabalho colaborativo. É pois tendo por base o que aqui é referido que se propõe, como plano de intervenção, a realização de uma oficina de formação que, em primeiro lugar, seria destinada aos docentes de Matemática e de Ciências Físico Químicas, devendo posteriormente ser alargada a outros grupos disciplinares e a todos os departamentos.
Resumo:
This paper discusses proposals for common euro area sovereign securities. Such instruments can potentially serve two functions: in the short-term, stabilize financialmarkets and banks and, in the medium-term, help improve the euro area economic governance framework through enhanced fiscal discipline and risk-sharing. Many questions remain onwhether financial instruments can ever accomplish such goals without bold institutional and political decisions, and,whether, in the absence of such decisions, they can create new distortions. The proposals discussed are also not necessarily competing substitutes; rather, they can be complements to be sequenced along alternative paths that possibly culminate in a fully-fledged Eurobond. The specific path chosen by policymakers should allow for learning and secure the necessary evolution of institutional infrastructures and political safeguards.
Resumo:
We consider the problem of scattering of time-harmonic acoustic waves by an unbounded sound-soft rough surface. Recently, a Brakhage Werner type integral equation formulation of this problem has been proposed, based on an ansatz as a combined single- and double-layer potential, but replacing the usual fundamental solution of the Helmholtz equation with an appropriate half-space Green's function. Moreover, it has been shown in the three-dimensional case that this integral equation is uniquely solvable in the space L-2 (Gamma) when the scattering surface G does not differ too much from a plane. In this paper, we show that this integral equation is uniquely solvable with no restriction on the surface elevation or slope. Moreover, we construct explicit bounds on the inverse of the associated boundary integral operator, as a function of the wave number, the parameter coupling the single- and double-layer potentials, and the maximum surface slope. These bounds show that the norm of the inverse operator is bounded uniformly in the wave number, kappa, for kappa > 0, if the coupling parameter h is chosen proportional to the wave number. In the case when G is a plane, we show that the choice eta = kappa/2 is nearly optimal in terms of minimizing the condition number.
Resumo:
Eight years of cloud properties retrieved from Television Infrared Observation Satellite-N (TIROS-N) Observational Vertical Sounder (TOVS) observations aboard the NOAA polar orbiting satellites are presented. The relatively high spectral resolution of these instruments in the infrared allows especially reliable cirrus identification day and night. This dataset therefore provides complementary information to the International Satellite Cloud Climatology Project (ISCCP). According to this dataset, cirrus clouds cover about 27% of the earth and 45% of the Tropics, whereas ISCCP reports 19% and 25%, respectively. Both global datasets agree within 5% on the amount of single-layer low clouds, at 30%. From 1987 to 1995, global cloud amounts remained stable to within 2%. The seasonal cycle of cloud amount is in general stronger than its diurnal cycle and it is stronger than the one of effective cloud amount, the latter the relevant variable for radiative transfer. Maximum effective low cloud amount over ocean occurs in winter in SH subtropics in the early morning hours and in NH midlatitudes without diurnal cycle. Over land in winter the maximum is in the early afternoon, accompanied in the midlatitudes by thin cirrus. Over tropical land and in the other regions in summer, the maximum of mesoscale high opaque clouds occurs in the evening. Cirrus also increases during the afternoon and persists during night and early morning. The maximum of thin cirrus is in the early afternoon, then decreases slowly while cirrus and high opaque clouds increase. TOVS extends information of ISCCP during night, indicating that high cloudiness, increasing during the afternoon, persists longer during night in the Tropics and subtropics than in midlatitudes. A comparison of seasonal and diurnal cycle of high cloud amount between South America, Africa, and Indonesia during boreal winter has shown strong similarities between the two land regions, whereas the Indonesian islands show a seasonal and diurnal behavior strongly influenced by the surrounding ocean. Deeper precipitation systems over Africa than over South America do not seem to be directly reflected in the horizontal coverage and mesoscale effective emissivity of high clouds.