914 resultados para path integral quantization


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The present essay shows strategies of improvement in a well succeded evolutionary metaheuristic to solve the Asymmetric Traveling Salesman Problem. Such steps consist in a Memetic Algorithm projected mainly to this problem. Basically this improvement applied optimizing techniques known as Path-Relinking and Vocabulary Building. Furthermore, this last one has being used in two different ways, in order to evaluate the effects of the improvement on the evolutionary metaheuristic. These methods were implemented in C++ code and the experiments were done under instances at TSPLIB library, being possible to observe that the procedures purposed reached success on the tests done

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Absorbance detection in capillary electrophoresis (CE), offers an excellent mass sensitivity, but poor concentration detection limits owing to very small injection volumes (normally I to 10 nL). This aspect can be a limiting factor in the applicability of CE/UV to detect species at trace levels, particularly pesticide residues. In the present work, the optical path length of an on-column detection cell was increased through a proper connection of the column (75 mu m i.d.) to a capillary detection cell of 180 mu m optical path length in order to improve detectability. It is shown that the cell with an extended optical path length results in a significant gain in terms of signal to noise ratio. The effect of the increase in the optical path length has been evaluated for six pesticides, namely, carbendazim, thiabendazole, imazalil, procymidone triadimefon, and prochloraz. The resulting optical enhancement of the detection cell provided detection limits of ca. 0.3 mu g/mL for the studied compounds, thus enabling the residue analysis by CE/UV.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study aims to analyzing the implementation of the Matrix Support proposal with professionals of Substitutive Services in Mental Health in the city of Natal/RN. The Matrix Support (MS) is an institutional arrangement which has been recently adopted by the Health Ministry, as an administrative strategy, for the construction of a wide care net in Mental Health, deviating the logic of indiscriminate follow-through changed by one of co-responsibility. In addition to this, its goal is to promote a major resolution as regards health assistance. Integral attention, as it is intended by the unique health system, may be reached by means of knowledge and practices interchange, establishing an interdisciplinary work logic, through an interconnected net of health services. For the accomplishment of this study, individual interviews of semi-structured character were used as instrument, with the coordinators and technical staff of the CAPs. The data collection was done in the following services: CAPS II ( East and West) and CAPS ad ( North and East), in the city of Natal/RN. The results point out that the CAPs to initiate of the discussion the process in the implementation of the MS aiming, to promote the reorganization and redefinition of the flow in the net, thus not acting in a fragmented way. Nevertheless, there is no effective articulation concerning the basic attention services, there is a major focus of the attention in mental health on the specialized services, little insertion in the territory and in the everyday life of the community

Relevância:

20.00% 20.00%

Publicador:

Resumo:

An interferometric technique was used to determine the temperature coefficient of the optical path length (dS/dT) as a function of the temperature in several optical glasses. The temperature range was between 25degreesC and 180degreesC. The studied samples included undoped and doped oxide glasses, such as low silica calcium aluminosilicate, phosphates, borates and also chalcogenides. The oxide glasses had dS/dT between 10 X 10(-6) K-1 and 20x10(-6) K-1, while for the chalcogenides, these were around 70 x 10(-6)K(-1). The results showed that dS/dTs increased with the temperature in all samples. For samples doped with Nd the dS/dT values were found to be independent of concentration. on the other hand, for the phosphate glass doped with Cr, dS/dT increased about 5% when compared with the Nd doped one. In conclusion, the used interferometric method, which is a considerably simpler and a lower cost technique, and is a useful tool to measure dS/dT in semi-transparent glasses as a function of the composition and temperature. (C) 2004 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This research assumes that for changes in health practices directed to an integral care, is crucial humanization, participation and autonomy of service users. In this sense, the research had investigated the issue of humanization involving users of the Family Health Strategy (FHS) in city of Mossoró, having as objectives: to analyze the perceptions of users on humanization in the production of health care in daily of Family Health Strategy, from these perceptions, identify elements featuring humanized and non-humanized in everyday practices related to production of health care; relate perceptions of users about humanization with the notions of extended clinic and social participation present in the National Humanization Policy (NHP); identify difficulties and potentialities in the production of health care from the perspective of humanization. It was a qualitative approach to data collection and it was used the methodology of Network Analysis of Everyday Life (NAEL), which allowed the questioning of health practices through an interactive discussion involving participants subjected. The analysis of data through the technique of content thematic analysis was performed and the results were interpreted related the Extended Clinic references and the users participation, related with the Gift Theory discussed by Marcel Mauss. The results indicated senses humanization linked to affection, reciprocity and honesty, highlighting as essential to humanized practices the trust, bonding, listening, dialogue and accountability. Were also mentioned other elements related to the organization of health services such as access and good functioning of the health services. The difficulties and potentialities show structural deficiencies of the health system and changes in the labor process. The participation of users deconstructing and reconstructing concepts remainder humanization in the production of health care is a key factor for the sedimentation of what is proposed in the HNP. Using the privileged space of the FHE to create more active people and understanding their needs and demands, is possible path to build a participative management

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The play operator has a fundamental importance in the theory of hysteresis. It was studied in various settings as shown by P. Krejci and Ph. Laurencot in 2002. In that work it was considered the Young integral in the frame of Hilbert spaces. Here we study the play in the frame of the regulated functions (that is: the ones having only discontinuities of the first kind) on a general time scale T (that is: with T being a nonempty closed set of real numbers) with values in a Banach space. We will be showing that the dual space in this case will be defined as the space of operators of bounded semivariation if we consider as the bilinearity pairing the Cauchy-Stieltjes integral on time scales.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

An algebraic reformulation of the Bohr-Sommerfeld (BS) quantization rule is suggested and applied to the study of bound states in one-dimensional quantum wells. The energies obtained with the present quantization rule are compared to those obtained with the usual BS and WKB quantization rules and with the exact solution of the Schrodinger equation. We find that, in diverse cases of physical interest in molecular physics, the present quantization rule not only yields a good approximation to the exact solution of the Schrodinger equation, but yields more precise energies than those obtained with the usual BS and/or WKB quantization rules. Among the examples considered numerically are the Poeschl-Teller potential and several anharmonic oscillator potentials. which simulate molecular vibrational spectra and the problem of an isolated quantum well structure subject to an external electric field.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A self-contained discussion of integral equations of scattering is presented in the case of centrally symmetric potentials in one dimension, which will facilitate the understanding of more complex scattering integral equations in two and three dimensions. The present discussion illustrates in a simple fashion the concept of partial-wave decomposition, Green's function, Lippmann-Schwinger integral equations of scattering for wave function and transition operator, optical theorem, and unitarity relation. We illustrate the present approach with a Dirac delta potential. (C) 2001 American Association of Physics Teachers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We discuss the Gupta-Bleuler quantization of the free electromagnetic field outside static black holes in the Boulware vacuum. We use a gauge which reduces to the Feynman gauge in Minkowski spacetime. We also discuss its relation with gauges used previously. Then we apply the low-energy sector of this held theory to investigate some low-energy phenomena. First, we discuss the response rate of a static charge outside the Schwarzschild black hole in four dimensions. Next, motivated by string physics, we compute the absorption cross sections of low-energy plane waves for the Schwarzschild and extreme Reissner-Nordstrom black holes in arbitrary dimensions higher than three.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Sigma model actions are constructed for the type II superstring compactified to four-and six-dimensional curved backgrounds which can contain non-vanishing Ramond-Ramond fields. These actions are N = 2 worldsheet superconformally invariant and can be covariantly quantized preserving manifest spacetime supersymmetry. They are constructed using a hybrid Version of superstring variables which combines features of the Ramond-Neveu-Schwarz and Green-Schwarz formalisms. For the AdS(2) x S-2 and AdS(3) x S-3 backgrounds, these actions differ from the classical Green-Schwarz actions by a crucial kinetic term for the fermions. Parts of this work have been done in collaborations with M Bershadsky, T Hauer, W Siegel, C Vafa, E Witten, S Zhukov and B Zwiebach.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this reply to the comment on 'Quantization rules for bound states in quantum wells' we point out some interesting differences between the supersymmetric Wentzel-Kramers-Brillouin (WKB) quantization rule and a matrix generalization of usual WKB (mWKB) and Bohr-Sommerfeld (mBS) quantization rules suggested by us. There are certain advantages in each of the supersymmetric WKB (SWKB), mWKB and mBS quantization rules. Depending on the quantum well, one of these could be more useful than the other and it is premature to claim unconditional superiority of SWKB over mWKB and mBS quantization rules.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We investigate some proposals to solve the electric charge quantization puzzle that simultaneously explain the recent measured deviation on the muon anomalous magnetic moment. For this we assess extensions of the electro-weak standard model spanning modifications on the scalar sector only. It is interesting to verify that one can have modest extensions which easily account for the solution for both problems.