866 resultados para One parameter family


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In this paper we consider the case of a Bose gas in low dimension in order to illustrate the applicability of a method that allows us to construct analytical relations, valid for a broad range of coupling parameters, for a function which asymptotic expansions are known. The method is well suitable to investigate the problem of stability of a collection of Bose particles trapped in one- dimensional configuration for the case where the scattering length presents a negative value. The eigenvalues for this interacting quantum one-dimensional many particle system become negative when the interactions overcome the trapping energy and, in this case, the system becomes unstable. Here we calculate the critical coupling parameter and apply for the case of Lithium atoms obtaining the critical number of particles for the limit of stability.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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For data obtained from horizontal soil column experiments, the determination of soil-water transport characteristics and functions would be aided by a single-form equation capable of objectively describing water content theta vs. time t at given position x(f). Our study was conducted to evaluate two such possible equations, one having the form of the Weibull frequency distribution, and the other being called a bipower form. Each equation contained three parameters, and was fitted by nonlinear least squares to the experimental data from three separate columns of a single soil. Across the theta range containing the measured data points obtained by gamma-ray attenuation, the two equations were in close agreement. The resulting family of theta(x(f),t) transients, as obtained from either equation, enabled the evaluation of exponent n in the t(n) dependence of the positional advance of a given theta. Not only was n found to be <0.5 at low theta values, but it also increased with theta and tended toward 0.5 as theta approached its sated (near-saturated) value. Some quantitative uncertainty in n(theta) does arise due to the reduced number of data points available at the higher water contents. Without claiming non-Boltzmann behavior (n < 0.5) as necessarily representative of all soils, we nonetheless consider n(theta) to be worthy of further study for evaluating its significance and implications.

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We prove that a 'positive probability' subset of the boundary of '{uniformly expanding circle transformations}' consists of Kupka-Smale maps. More precisely, we construct an open class of two-parameter families of circle maps (f(alpha,theta))(alpha,theta) such that, for a positive Lebesgue measure subset of values of alpha, the family (f(alpha,theta))(theta) crosses the boundary of the uniformly expanding domain at a map for which all periodic points are hyperbolic (expanding) and no critical point is pre-periodic. Furthermore, these maps admit an absolutely continuous invariant measure. We also provide information about the geometry of the boundary of the set of hyperbolic maps.

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The location of invariant tori for a two-dimensional Hamiltonian mapping exhibiting mixed phase space is discussed. The phase space of the mapping shows a large chaotic sea surrounding periodic islands and limited by a set of invariant tori. Given the mapping considered is parameterised by an exponent γ in one of the dynamical variables, a connection with the standard mapping near a transition from local to global chaos is used to estimate the position of the invariant tori limiting the size of the chaotic sea for different values of the parameter γ. © 2011 Elsevier B.V. All rights reserved.

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The universities have realized the importance of extending their knowledge to the population through the provision of services. Thus, this paper presents the data obtained in an agreement between UNESP/Laboratory of Paternity and Public Defender Service in São Paulo State to make DNA paternity tests.

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Fabry's disease corresponds to an inherited disorder transmitted by an X-linked recessive gene. It generates a dysfunction of glycosphingolipid metabolism due to an enzymatic deficiency of alpha-galactosidase activity, resulting in glycosphingolipid deposits in all areas of the body. The clinical (heart, kidney, and central nervous system) manifestations are more severe in hemizygous boys than in heterozygous girls. They appear during childhood or adolescence: acroparesthesia, joint pain, angiokeratoma, corneal dystrophy, hypohydrosis or anhydrosis, and renal failure. The otoneurologic symptoms consist of hearing fluctuation, progressive unilateral or bilateral hearing loss, and episodes of vertigo or dizziness. Otoneurologic findings in 12 of 26 members of the same family are presented: the mother and 9 of her 12 children, as well as 2 of her 14 grandchildren: 4 healthy persons, 4 heterozygous female carriers, and 4 hemizygous male patients. Three of the male patients had fluctuation of hearing, sudden hearing loss, and episodes of vertigo and dizziness. The otoneurologic examinations showed a bilateral cochleovestibular deficit (n = 1), a right cochleovestibular deficit (n = 1), and a bilateral hearing loss combined with a right vestibular deficit (n = 1). Histopathologic evidence of glycosphingolipid accumulation in vascular endothelial and ganglion cells, as well as atrophy of the stria and spiral ligament, might explain the otoneurologic symptoms and findings.

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Family offices are organisations dedicated to the management of entrepreneurial families’ private wealth. Based on agency theory, we analyse types of family offices with regard to the families’ goals and the control mechanisms used to ensure goal achievement. Family-dominant management and private client structures involve stronger emphasis on non-financial goals in single and multi-family offices than in non-family-dominant management and open client structures. Variations in family involvement, ranging from family dominance to the complete absence of family ownership and/or management, and diverse client structures justify the differential reliance on formal and informal control mechanisms.