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Search Results: 1 - 10 of 5596 matches for " Renato; "
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Some Remarks on Energy Storage and Energetic Complementarity  [PDF]
Renato M. Brito
Energy and Power Engineering (EPE) , 2017, DOI: 10.4236/epe.2017.99031
Abstract: This letter to the editor presents some notes related to the technological and economic limitations of the means actually available for energy storage and highlights the role that can be played by the notion of energetic complementarity in order to make feasible alternatives for a better use of the energy resources at our disposal. The notion of complementarity may represent a major advance in the design of energy generation projects, but its application depends on a broader conception of the projects and the contexts in which they are included.
On the orthogonalization of arbitrary Boolean formulae
Renato Bruni
Advances in Decision Sciences , 2005, DOI: 10.1155/jamds.2005.61
Abstract: The orthogonal conjunctive normal form of a Boolean function is a conjunctive normal form in which any two clauses contain at least a pair of complementary literals. Orthogonal disjunctive normal form is defined similarly. Orthogonalization is the process of transforming the normal form of a Boolean function to orthogonal normal form. The problem is of great relevance in several applications, for example, in the reliability theory. Moreover, such problem is strongly connected with the well-known propositional satisfiability problem. Therefore, important complexity issues are involved. A general procedure for transforming an arbitrary CNF or DNF to an orthogonal one is proposed. Such procedure is tested on randomly generated Boolean formulae.
Potential Energy Surfaces Using Algebraic Methods Based on Unitary Groups
Renato Lemus
Advances in Physical Chemistry , 2011, DOI: 10.1155/2011/593872
Abstract: This contribution reviews the recent advances to estimate the potential energy surfaces through algebraic methods based on the unitary groups used to describe the molecular vibrational degrees of freedom. The basic idea is to introduce the unitary group approach in the context of the traditional approach, where the Hamiltonian is expanded in terms of coordinates and momenta. In the presentation of this paper, several representative molecular systems that permit to illustrate both the different algebraic approaches as well as the usual problems encountered in the vibrational description in terms of internal coordinates are presented. Methods based on coherent states are also discussed. 1. Introduction The description of molecular systems involves the solution of the corresponding Schr?dinger equation. This task is so difficult that an approach involving just numerical methods needs powerful computers even for three-or four-particle systems. An alternative approach is based on choosing the basis functions in such a way that they resemble the exact eigenfunctions as much as possible. The suitable basis are obtained by making approximations that simplify the Hamiltonian of the molecule. The advantage of this method is that the functions reproduce correctly the gross features of the spectrum, and consequently they provide a better physical insight in understanding the solutions. The first step in simplifying the molecular problem consists in taking advantage of the large difference between the nucleus and electron masses, a fact that leads to the Born-Oppenheimer approximation [1, 2]. As a result of this approximation the original Schr?dinger equation is split into two coupled equations, one corresponding to the electronic degrees of freedom which is solved for many nuclear geometries and the other one associated with the rotation-vibration Schr?dinger equation for the nuclei whose potential is basically provided by the electronic energy [3, 4]. On the other hand, the rotation-vibration Schr?dinger equation is usually solved making the rigid-rotor approximation together with the harmonic oscillator approximation. The total wave function is then approximated as the direct product of three contributions: electronic, rotational, and vibrational wave functions. Corrections to this description are allowed by introducing the braking of the Born-Oppenheimer approximation, distortion effects, anharmonicity, centrifugal distortion, and Coriolis coupling [3–5]. Within the Born-Oppenheimer approximation the potential energy surface (PES) is provided by the solution of
Ecological Gradients Influencing Waterbird Communities in Black Water Lakes in the Anavilhanas Archipelago, Central Amazonia
Renato Cintra
International Journal of Ecology , 2012, DOI: 10.1155/2012/801683
Abstract: For the first time, and in a large spatial scale, the influence of ecological properties on the aquatic bird community of black water lakes in Brazilian Amazonia is evaluated. Bird surveys were conducted in 45 lakes. A total of 3626 individuals in 48 bird species were recorded; of these, 31 are aquatic, and 18 of these are primarily piscivorous. Bird richness and abundance were not significantly related to lake shape and productivity but were influenced by hydrological period (low versus high), water depth, transparency, lake isolation, and habitat richness. Matrices of bird species by lake were subjected to multivariate analyses (NMDS) to evaluate how these parameters influence bird community. The variation in bird species composition was positively correlated to lake depth and isolation and negatively correlated to water transparency and habitat richness. The results indicate that period, lake physical characteristics (depth, water transparency), isolation, and habitat richness are determinants of aquatic bird community composition in the black water lake systems of Amazonia.
Quantum Numbers and the Eigenfunction Approach to Obtain Symmetry Adapted Functions for Discrete Symmetries
Renato Lemus
Symmetry , 2012, DOI: 10.3390/sym4040667
Abstract: The eigenfunction approach used for discrete symmetries is deduced from the concept of quantum numbers. We show that the irreducible representations (irreps) associated with the eigenfunctions are indeed a shorthand notation for the set of eigenvalues of the class operators (character table). The need of a canonical chain of groups to establish a complete set of commuting operators is emphasized. This analysis allows us to establish in natural form the connection between the quantum numbers and the eigenfunction method proposed by J.Q. Chen to obtain symmetry adapted functions. We then proceed to present a friendly version of the eigenfunction method to project functions.
Especies de nematodos fitoparasíticos en venezuela
Interciencia , 2002,
Abstract: an outline on the present status of plant nematology in venezuela is presented, including a list of the 115 plant parasitic nematodes species identified in the country. the most damaging species present were bursaphelenchus (=rhadinaphelenchus) cocophillus, ditylenchus dipsaci, globodera rostochiensis, g. pallida, meloidogyne incognita, m. javanica, m. exigua, m. hapla, pratylenchus brachyurus, p. penetrans, p. scribneri, p. zeae, radopholus similis, rotylenchulus reniformis and tylenchulus semipenetrans. the damaging effects induced by meloidogyne spp. and other plant parasitic nematodes are briefly discussed.
O gênero Miconia (Melastomataceae) no Estado do Paraná, Brasil
Goldenberg, Renato;
Acta Botanica Brasilica , 2004, DOI: 10.1590/S0102-33062004000400024
Abstract: the genus miconia ruiz & pav. presents 32 species in the state of paraná (brazil).these species occur mostly at the eastern portion of the state (coastal region, "serra do mar" and "primeiro planalto") and belong to seven sections (from a total 11 in the genus); the most important sections are glossocentrum (14 spp.) and miconia (7 spp.). this work presents an identification key, descriptions and selected collection lists for the miconia species from state of paraná.
Religi?o n?made ou germe do estado? Pierre e Hélène Clastres e a vertigem tupi
Sztutman, Renato;
Novos Estudos - CEBRAP , 2009, DOI: 10.1590/S0101-33002009000100008
Abstract: this article analyses how a particular question - the irruption of political power focuses among the ancient brazilian coastal tupi - was treated both by pierre clastres and hélène clastres. although her reflection continues the project for a political anthropology, proposed by him, it is important to point out both the agreements and disagreements between the authors, in order to draw new directions to the debate they have initiated. in this sense, one intend to evaluate the most recent developments of the tupi-guarani anthropology, considering peoples of the past, but also of the present time.
Heparina de baixo peso molecular no tratamento da tromboembolia pulmonar
Jornal de Pneumologia , 2002, DOI: 10.1590/S0102-35862002000300005
Abstract: this article reviews the pharmacokinetic properties of low-molecular weight heparins, compares the results of their use to that of unfractioned heparin in a pulmonary embolism treatment, showing they are a safe an effective alternative. the authors suggest that low-molecular-weight heparins administered subcutaneously once or twice-daily and without frequent laboratory monitoring have permitted out-of-hospital or short hospitalization management in some cases of pulmonary embolism, resulting in cost savings and increased patient satisfaction.
ética e profética nas Mitológicas de Lévi-Strauss
Sztutman, Renato;
Horizontes Antropológicos , 2009, DOI: 10.1590/S0104-71832009000100012
Abstract: this article focus claude lévi-strauss' reflection on amerindian ethic and political thought. we suggest that we could read many passages of mythologiques as if they contained sorts of replies as well as developments of some of pierre clastres' provocations and critics directed to structuralism. we will analyse particularly two books: les origines des manières à table, mythologiques' third volume, and histoire de lynx, the last of the petites mythologiques. the first one ends with an interesting reflection on the "mythical moralism", while the second one starts with the problem of how amerindian mythologies can offer interpretations of history, interpretations of the "encounter" with europeans, for instance. these, we suppose, must be on the basis of what ethnological recent literature called "prophetic movements".
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