979 resultados para Internal organization
Resumo:
The extraordinary importance that has been attached to money throughout the ages may be appreciated when such modern writers as Alexander Delmar suggest that the history of money is the history of civilization. While this view is not accepted by most writers of the subject, all are nevertheless agreed that money plays a role of enormous importance in the affairs of men. Even in the classics are found quotations which stress this importance of the pecuniary unit upon ethical as well as economic standards.
Resumo:
The evaluation and comparison of internal cluster validity indices is a critical problem in the clustering area. The methodology used in most of the evaluations assumes that the clustering algorithms work correctly. We propose an alternative methodology that does not make this often false assumption. We compared 7 internal cluster validity indices with both methodologies and concluded that the results obtained with the proposed methodology are more representative of the actual capabilities of the compared indices.
Resumo:
The process of prophage integration by phage λ and the function and structure of the chromosomal elements required for λ integration have been studied with the use of λ deletion mutants. Since attφ, the substrate of the integration enzymes, is not essential for λ growth, and since attφ resides in a portion of the λ chromosome which is not necessary for vegetative growth, viable λ deletion mutants were isolated and examined to dissect the structure of attφ.
Deletion mutants were selected from wild type populations by treating the phage under conditions where phage are inactivated at a rate dependent on the DNA content of the particles. A number of deletion mutants were obtained in this way, and many of these mutants proved to have defects in integration. These defects were defined by analyzing the properties of Int-promoted recombination in these att mutants.
The types of mutants found and their properties indicated that attφ has three components: a cross-over point which is bordered on either side by recognition elements whose sequence is specifically required for normal integration. The interactions of the recognition elements in Int-promoted recombination between att mutants was examined and proved to be quite complex. In general, however, it appears that the λ integration system can function with a diverse array of mutant att sites.
The structure of attφ was examined by comparing the genetic properties of various att mutants with their location in the λ chromosome. To map these mutants, the techniques of heteroduplex DNA formation and electron microscopy were employed. It was found that integration cross-overs occur at only one point in attφ and that the recognition sequences that direct the integration enzymes to their site of action are quite small, less than 2000 nucleotides each. Furthermore, no base pair homology was detected between attφ and its bacterial analog, attB. This result clearly demonstrates that λ integration can occur between chromosomes which have little, if any, homology. In this respect, λ integration is unique as a system of recombination since most forms of generalized recombination require extensive base pair homology.
An additional study on the genetic and physical distances in the left arm of the λ genome was described. Here, a large number of conditional lethal nonsense mutants were isolated and mapped, and a genetic map of the entire left arm, comprising a total of 18 genes, was constructed. Four of these genes were discovered in this study. A series of λdg transducing phages was mapped by heteroduplex electron microscopy and the relationship between physical and genetic distances in the left arm was determined. The results indicate that recombination frequency in the left arm is an accurate reflection of physical distances, and moreover, there do not appear to be any undiscovered genes in this segment of the genome.
Resumo:
Electric dipole internal conversion has been experimentally studied for several nuclei in the rare earth region. Anomalies in the conversion process have been interpreted in terms of nuclear structure effects. It was found that all the experimental results could be interpreted in terms of the j ∙ r type of penetration matrix element; the j ∙ ∇ type of penetration matrix element was not important. The ratio λ of the El j ∙ r penetration matrix element to the El gamma-ray matrix element was determined from the experiments to be:
Lu175,396 keV, λ = - 1000 ± 100;
282 keV, λ = 500 ± 100;
144 keV, λ = 500 ± 250;
Hf177, 321 keV λ = - 1400 ± 200;
208 keV λ = - 90 ± 40;
72 keV |λ| ≤ 650;
Gd155, 86 keV λ = - 150 ± 100;
Tm169, 63 keV λ = - 100 ± 100;
W182, 152 keV, λ = - 160 ±80;
67 keV, λ = - 100 ± 100.
Predictions for λ are made using the unified nuclear model.
Resumo:
Experimental studies of nuclear effects in internal conversion in Ta181 and Lu175 have been performed. Nuclear structure effects (“penetration” effects), in internal conversion are described in general. Calculation of theoretical conversion coefficients are outlined. Comparisons with the theoretical conversion coefficient tables of Rose and Sliv and Band are made. Discrepancies between our results and those of Rose and Sliv are noted. The theoretical conversion coefficients of Sliv and Band are in substantially better agreement with our results than are those of Rose. The ratio of the M1 penetration matrix element to the M1 gamma-ray matrix element, called λ, is equal to + 175 ± 25 for the 482 keV transition in Ta181 . The results for the 343 keV transition in Lu175 indicate that λ may be as large as – 8 ± 5. These transitions are discussed in terms of the unified collective model. Precision L subshell measurements in Tm169 (130keV), W182 (100 keV), and Ta181 (133 keV) show definite systematic deviations from the theoretical conversion coefficients. The possibility of explaining these deviations by penetration effects is investigated and is shown to be excluded. Other explanations of these anomalies are discussed.
Resumo:
Part I.
The interaction of a nuclear magnetic moment situated on an internal top with the magnetic fields produced by the internal as well as overall molecular rotation has been derived following the method of Van Vleck for the spin-rotation interaction in rigid molecules. It is shown that the Hamiltonian for this problem may be written
HSR = Ῑ · M · Ĵ + Ῑ · M” · Ĵ”
Where the first term is the ordinary spin-rotation interaction and the second term arises from the spin-internal-rotation coupling.
The F19 nuclear spin-lattice relaxation time (T1) of benzotrifluoride and several chemically substituted benzotrifluorides, have been measured both neat and in solution, at room temperature by pulsed nuclear magnetic resonance. From these experimental results it is concluded that in benzotrifluoride the internal rotation is crucial to the spin relaxation of the fluorines and that the dominant relaxation mechanism is the fluctuating spin-internal-rotation interaction.
Part II.
The radiofrequency spectrum corresponding to the reorientation of the F19 nuclear moment in flurobenzene has been studied by the molecular beam magnetic resonance method. A molecular beam apparatus with an electron bombardment detector was used in the experiments. The F19 resonance is a composite spectrum with contributions from many rotational states and is not resolved. A detailed analysis of the resonance line shape and width by the method of moments led to the following diagonal components of the fluorine spin-rotational tensor in the principal inertial axis system of the molecule:
F/Caa = -1.0 ± 0.5 kHz
F/Cbb = -2.7 ± 0.2 kHz
F/Ccc = -1.9 ± 0.1 kHz
From these interaction constants, the paramagnetic contribution to the F19 nuclear shielding in C6H5F was determined to be -284 ± ppm. It was further concluded that the F19 nucleus in this molecule is more shielded when the applied magnetic field is directed along the C-F bond axis. The anisotropy of the magnetic shielding tensor, σ” - σ⊥, is +160 ± 30 ppm.
Resumo:
The phase contrast across the crystal thickness induced by the internal field is measured by the digital holographic interferometry just after the congruent lithium niobate crystal is partially poled. The direction of applied external field is antiparallel to that of internal field, and the measured phase contrast varies linearly with the applied external field. A new internal field is obtained by this method and named effective internal field. The distinct discrepancy between effective and equivalent internal fields is observed. The authors attribute this effect to the new macroscopic representation of elastic dipole components of defect complex in the crystal. (c) 2007 American Institute of Physics.
Resumo:
Esse estudo teve por objetivo analisar as dinâmicas de mudanças organizacionais transcorridas em um estabelecimento de saúde. Conduzido através metodologia de estudo de caso descritivo, teve como campo de pesquisa o Instituto de Hematologia do Estado do Rio de Janeiro. Buscando conhecer o papel da preparação para acreditação na dinâmica da mudança em uma organização de saúde essa pesquisa foi assim estruturada: abordagem dos problemas encontrados nas mudanças organizacionais em estabelecimentos de saúde; quadro teórico estruturado com uma revisão de literatura; embasamento da metodologia aplicada, com definição de instrumentos de coletas de dados, de material e atores implicados no levantamento para realização da análise qualitativa. O estudo analisou as seguintes variáveis: a natureza da mudança focalizando a extensão, ritmo e trajetória; as estratégias de ação, contemplando as situações de adesões e resistência e a concepção, verificando se as mudanças foram indutivas ou dedutivas. O resultado demonstrou que a preparação para acreditação naquele hospital, proporcionou mudanças com movimentos lentos, mas com continuidade em todos os setores do estabelecimento. Foi identificada participação mais ativa de um grupo de profissionais identificados como facilitadores, funcionando como multiplicadores. A abrangência das estratégias aplicadas foram desde as reuniões em assembléias gerais, á formação de grupos de estudo por setores para entendimento do manual de padrões de acreditação. Foram realizados processos internos de auto-avaliação com base no manual de acreditação. Em relação á concepção, o processo de mudança foi motivado pela determinação da direção do hospital para obtenção do certificado de acreditação internacional. Quanto á resistência e adesão, o estudo demonstrou que a participação de uma grande maioria dos profissionais foi motivada pelo desejo de aprender e desenvolver novas práticas que proporcionasse a melhoria da qualidade da assistência. A análise de dados aponta certa resistência da categoria médica no início do processo. Do ponto de vista organizacional, foram criadas novas estruturas. A conclusão do estudo: O processo de preparação para acreditação na unidade de saúde estudada demonstrou ser um instrumento capaz de promover mudanças em organizações de saúde.
Resumo:
The dynamic interaction of limb segments during movements that involve multiple joints creates torques in one joint due to motion about another. Evidence shows that such interaction torques are taken into account during the planning or control of movement in humans. Two alternative hypotheses could explain the compensation of these dynamic torques. One involves the use of internal models to centrally compute predicted interaction torques and their explicit compensation through anticipatory adjustment of descending motor commands. The alternative, based on the equilibrium-point hypothesis, claims that descending signals can be simple and related to the desired movement kinematics only, while spinal feedback mechanisms are responsible for the appropriate creation and coordination of dynamic muscle forces. Partial supporting evidence exists in each case. However, until now no model has explicitly shown, in the case of the second hypothesis, whether peripheral feedback is really sufficient on its own for coordinating the motion of several joints while at the same time accommodating intersegmental interaction torques. Here we propose a minimal computational model to examine this question. Using a biomechanics simulation of a two-joint arm controlled by spinal neural circuitry, we show for the first time that it is indeed possible for the neuromusculoskeletal system to transform simple descending control signals into muscle activation patterns that accommodate interaction forces depending on their direction and magnitude. This is achieved without the aid of any central predictive signal. Even though the model makes various simplifications and abstractions compared to the complexities involved in the control of human arm movements, the finding lends plausibility to the hypothesis that some multijoint movements can in principle be controlled even in the absence of internal models of intersegmental dynamics or learned compensatory motor signals.
Resumo:
In laser applications, the size of the focus spot can be reduced beyond the diffraction limit with a thin film of strong nonlinear optical Kerr effect. We present a concise theoretical simulation of the device. The origin of the super-resolution is found to be mainly from the reshaping effect due to the strongly nonlinear refraction mediated multi-interference inside the thin film. In addition, both diffraction and self-focusing effects have been explored and found negligible for highly refractive and ultrathin films in comparison with the reshaping effect. Finally, the theoretic model has been verified in experiments with single Ge2Sb2Te5 film and SiN/Si/SiN/Ge2Sb2Te2 multilayer structures. (c) 2006 American Institute of Physics.
Resumo:
No âmbito da organização do espaço, os cemitérios efetivam-se como artefatos de grande relevância e suscetíveis a diversas análises e interpretações. Na realidade, os cemitérios presentes nas cidades apresentam vívidas e vibrantes geografias. Marcas impressas pelo homem, refletem a estrutura social, cultural, religiosa, identitária da comunidade que os criaram, sendo impregnados de valores e significados, compondo, desta maneira, um rico e denso quadro cultural e de experiências. Mais do que isso, os campos santos apresentam particularidades e singularidades, uma vez que contemplam morfologias, estilos arquitetônicos e significados diferentes. Em outras palavras, compõem pontos singulares no espaço das cidades e, ao mesmo tempo, seus domínios internos compõem singulares cidades com seus traçados, monumentos e túmulos. Nestes termos, a dissertação tem como objetivo explorar/traduzir o Cemitério São João Batista, localizado no município do Rio de Janeiro. Pretende-se abordar e analisar os usos que ocorrem no espaço interno da necrópole em questão, compreendendo que, através destes, serão revelados os conteúdos das práticas sociais, espaciais e simbólicas. Diante do exposto, a pesquisa torna-se relevante por abarcar os afamados campos dos mortos do Rio de Janeiro, priorizando um tema negligenciado pelas análises geográficas no Brasil. De tal sorte, a dissertação transforma-se em um veio para que outros pesquisadores ousem na mesma linha, isto é, enveredando por um assunto tão rico no qual a geografia, com suas vertentes, permite de forma extraordinária a sua compreensão.
Resumo:
Esta pesquisa tem como objetivo investigar a categoria do tempo interno ou aspecto verbal na organização narrativa do romance Vidas Secas, de Graciliano Ramos. Repassa-se criticamente, com base na leitura de algumas obras representativas, a contribuição tradicional ao estudo desse conceito, mesmo nos casos em que não é identificado pelo termo aspecto. Em seguida, foram abordados a conceituação da categoria do aspecto verbal e alguns conceitos sobre a semântica do perfectivo e do imperfectivo segundo estudos empreendidos por linguistas diversos. Abordou-se ainda a variedade de meios de expressão do aspecto: o lexical, o sintático, o derivacional e o flexional. No segundo momento, procedeu-se a uma análise da funcionalidade textual do aspecto como recurso de organização do texto narrativo. Para tanto, foram levados em conta os conceitos de gênero textual e de modo de organização do discurso. Estes comentários tiveram por objeto o primeiro e o nono capítulos do romance, respectivamente Mudança e Baleia