914 resultados para Feynman-Kac formula Markov semigroups principal eigenvalue


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Outsourcing has emerged as one of the new ways of guiding the work. For its advantages and be consistent with the paradigms of managerial reform, outsourcing also started to be used in the Public Administration. However, taking into account the particularities of the latter, some issues are relevant when outsourcing concluded with the State. Gains notoriety, for example, the step of monitoring these contracts, to the extent that, from this activity, we can avoid the negative effects of outsourcing like the fact that the state will pay for labor and wage liens that are obligation of the company providing the services. This study aims to understand the perception that this process is under the Federal University of Rio Grande do Norte, from the point of view of different stakeholders, also explaining the motivations that these agents have to perform the supervisory process. As a theoretical basis was used the Agency Theory, which reinforces the supervisory activities as a necessary means to minimize moral hazard and adverse selection, seeking to understand not only the different motivations tax contracts to properly perform their duties, but also analyze other phenomena arising from this contractual relationship. To achieve the proposed objectives, were taken a literature review and a presentation of how to organize the management and oversight of contracts in UFRN. The methodological procedures included questionnaires and interviews with those involved in the process. After analyzing the results obtained in the survey instruments , and also based on the laws, regulations and instructions governing the procurement process within the UFRN, it was concluded that the process of overseeing the outsourcing of labor contracts in UFRN is not fully institutionalized, some points should be strengthened in order to have the consolidation of this process, highlighting the need for training of UFRN servers that act as tax, the knowledge that the contractual penalties are applied effectively, the need that there is a supervisor of tax of contractors and also the realization of the rotation system of outsourced employees

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Glandular atrophy is one of several alterations which can aflict the salivary glands, caused generally by obstructive lesions such as sialo1ithiasis, infections or compression by neoplastic processes arnong others. In this work, a morphological and immunohistochemical study was carried out in rat parotid glands, which were submitted to obstruction of the main excretory duct suffering atrophy at varied time intervals, with the aim of appraising the behavior of myoepithelial cells during the process of glandular atrophy. It was analized the immunohistochemical expression of calponin which detects myoepithelial cells in the parotids of 28 animaIs, which were divided into 7 groups, each one made up of 4 rats, afier the ductal ligature procedure, in the following time intervals: zero hour (control), 24 hours, 7, 15, 21, 30 and 60 days. Analysis of the immunohistochemicaI profile was carried through in which the calponin expression was veritied through its distribution pattem and numericaI index. All specimens exhibited positivity for calponin in myoepithelial cells which were distributed around the acini and the ductaI structures, a small number of positiveIy marked cells being detected in the controI group and in the 24-hour group when compared to subsequent ones, where it was perceived a Iarge increase in the number of positiveIy marked cens, mainly surrounding the ductiform structures which originated during the obstruction time. Upon application of statistical tests it was verified that the rise in the number the myoepithelial positive cells for calponin, when the control groups (zero hour) was compared to the 7, 15,21, 30 and 60-day groups afier obstruction, was statistica1ly significant. It was concluded then that the detected rise probably carne about due to an elevation in the rate of proliferation of the myoepitheliaI cells subsequent to the ductal obstruction, associated with a growing resistance of these cells to glandular atrophy.

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The thalamus plays an important role in the sensorial processing information, in this particular case, the visual information. Several neuronal groups have been characterized as conductors and processors of important sensorial information to the cerebral cortex. The lateral geniculate complex is one to them, and appears as a group very studied once it is responsible, in almost all totality, for the processing of visual information. Among the nuclei that constitute the lateral geniculate complex we highlight the dorsal lateral geniculate nucleus of the thalamus (DLG), the main thalamic relay for the visual information. This nucleus is located rostral and lateral to medial geniculate nucleus and ventral to thalamic pulvinar nucleus in most of the mammals. In the primates humans and non-humans, it presents as a laminate structure, arranged in layers, when observed in coronal sections. The objective of this work was to do a mapping of the retinal projections and a citoarchictetonic and neurochemical characterization of DLG in the marmoset (Callithrix jacchus), a New World primate. The retinal projections were traced by anterograde transport of subunit b of cholera toxin (CTb), the citoarchicteture was described by Nissl method, and to neurochemical characterization immunohistochemicals technical were used to examine the main neurotransmitters and neuroatives substances present in this neural center. In DGL of marmoset thalamus, in coronal sections labeled by Nissl method, was possible to visualize the division of this nucleus in four layers divided in two portions: magnocellular and parvocellular. The retinal projections were present being visualized fibers and terminals immunorreactives to CTb (IR-CTb) in the DLG ipsilateral and contralateral. And through the immunohistochemicals techniques was observed that DLG contain cells, fibers and/or terminals immunoreactives against neuronal nuclear protein, subunits of AMPA 15 glutamate receptors (GluR1, GluR2/3, GluR4), choline acetyltransferase, serotonin, glutamic acid decarboxylase, binding calcium proteins (calbindin, parvalbumin and calretinin), vasopressin, vasoactive intestinal polypeptide, and an astrocyte protein, glial fibrillary acidic protein.

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The general assumption under which the (X) over bar chart is designed is that the process mean has a constant in-control value. However, there are situations in which the process mean wanders. When it wanders according to a first-order autoregressive (AR (1)) model, a complex approach involving Markov chains and integral equation methods is used to evaluate the properties of the (X) over bar chart. In this paper, we propose the use of a pure Markov chain approach to study the performance of the (X) over bar chart. The performance of the chat (X) over bar with variable parameters and the (X) over bar with double sampling are compared. (C) 2011 Elsevier B.V. All rights reserved.

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Parenting styles concern overall interaction characteristics between parents and children. To assess them, it is important to build and adapt valid and reliable instruments. The main objectives of this dissertation were to translate, adapt and evaluate the psychometric properties of the Young Parenting Inventory (YPI) for the Brazilian context, as seek associations between the YPI and Familiogram Test (FG). In current study, YPI was adapted to Portuguese by backtranslation method. Content analyses were made by five judges. 920 high school and college students (543 females), whose ages were between 14 and 69 years (M = 21.3, SD = 6.1), filled out the research instruments. Data were collected in Natal, Petrolina and Brasilia cities and Porto Alegre metropolitan region. The results confirmed the existence of five factors. Final version of the YPI was composed by 49 items. Exploratory factorial analysis (principal components) were conducted using oblimin rotation. Five factors extracted explained 45.12% of the maternal scale variance and 47.59% of paternal scale. Each factor explained, at least, 3% of the variance and showed Eigenvalue over than 1.5. All items have factorial loadings values above 0.3. The confirmatory factorial analysis has showed fit statistics reasonably adequate: for maternal scale,  ² [1114] = 4636.38, p < 0.001,  ² / df = 4.16, with GFI = 0.83, AGFI = 0.81 and RMSEA = 0.06; for paternal scale,  ² [1114] = 5133.69 p < 0.001,  ² / df = 4.61, with GFI = 0.81, AGFI = 0.79 and RMSEA = 0,06. Thus, final instrument was composed by the following factors: (I) Disconnection and Rejection ( = 0.89 and 0.90), (II) Affectivity and Emotional Stability ( = 0.85 and 0.88); (III) Overvigilance and Other Directedness ( = 0.83 and 0.85), (IV) Overprotection and Impaired Autonomy ( = 0.78 and 0.79) and (V) Impaired Limits ( = 0.66 and 0.71). Finally, relations between the YPI and FG were assessed. Pearson's correlations between the YPI and FG showed moderated associations, particularly between the factors Affectivity (YPI) and Affection (FG) (r = 0.69 and 0.7 for maternal and paternal scale, respectively); and the factors Disconnection and Rejection (YPI) and Conflict (FG) (r = 0.59 and 0.58). The regression models indicated that over than 40% of variance of factors of FG can be predicted by factors of YPI. Beta coefficients for Affection-Affectivity relation were 0.67 (maternal scale) and 0.53 (paternal scale); for Disconnection-Conflict relation were 0.31 (maternal scale) and 0.44 (paternal scale). We conclude the YPI has adequate psychometric parameters and can be used in future research in this area. However, adjustments in the structure of the YPI were made. Moreover, it is suggested further studies to consider other samples and variables, increasing the knowing of parenting styles and the Young‟s theory in the Brazilian context

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Este trabalho tem como objetivo o estudo do comportamento assintótico da estatística de Pearson (1900), que é o aparato teórico do conhecido teste qui-quadrado ou teste x2 como também é usualmente denotado. Inicialmente estudamos o comportamento da distribuição da estatística qui-quadrado de Pearson (1900) numa amostra {X1, X2,...,Xn} quando n → ∞ e pi = pi0 , 8n. Em seguida detalhamos os argumentos usados em Billingley (1960), os quais demonstram a convergência em distribuição de uma estatística, semelhante a de Pearson, baseada em uma amostra de uma cadeia de Markov, estacionária, ergódica e com espaço de estados finitos S

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In this work we study the Hidden Markov Models with finite as well as general state space. In the finite case, the forward and backward algorithms are considered and the probability of a given observed sequence is computed. Next, we use the EM algorithm to estimate the model parameters. In the general case, the kernel estimators are used and to built a sequence of estimators that converge in L1-norm to the density function of the observable process

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In this work we studied the consistency for a class of kernel estimates of f f (.) in the Markov chains with general state space E C Rd case. This study is divided into two parts: In the first one f (.) is a stationary density of the chain, and in the second one f (x) v (dx) is the limit distribution of a geometrically ergodic chain

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Os Algoritmos Genético (AG) e o Simulated Annealing (SA) são algoritmos construídos para encontrar máximo ou mínimo de uma função que representa alguma característica do processo que está sendo modelado. Esses algoritmos possuem mecanismos que os fazem escapar de ótimos locais, entretanto, a evolução desses algoritmos no tempo se dá de forma completamente diferente. O SA no seu processo de busca trabalha com apenas um ponto, gerando a partir deste sempre um nova solução que é testada e que pode ser aceita ou não, já o AG trabalha com um conjunto de pontos, chamado população, da qual gera outra população que sempre é aceita. Em comum com esses dois algoritmos temos que a forma como o próximo ponto ou a próxima população é gerada obedece propriedades estocásticas. Nesse trabalho mostramos que a teoria matemática que descreve a evolução destes algoritmos é a teoria das cadeias de Markov. O AG é descrito por uma cadeia de Markov homogênea enquanto que o SA é descrito por uma cadeia de Markov não-homogênea, por fim serão feitos alguns exemplos computacionais comparando o desempenho desses dois algoritmos

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In this work, we present a risk theory application in the following scenario: In each period of time we have a change in the capital of the ensurance company and the outcome of a two-state Markov chain stabilishs if the company pays a benece it heat to one of its policyholders or it receives a Hightimes c > 0 paid by someone buying a new policy. At the end we will determine once again by the recursive equation for expectation the time ruin for this company

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In this work, we studied the strong consistency for a class of estimates for a transition density of a Markov chain with general state space E ⊂ Rd. The strong ergodicity of the estimates for the density transition is obtained from the strong consistency of the kernel estimates for both the marginal density p(:) of the chain and the joint density q(., .). In this work the Markov chain is supposed to be homogeneous, uniformly ergodic and possessing a stationary density p(.,.)

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In production lines, the entire process is bound to unexpected happenings which may cost losing the production quality. Thus, it means losses to the manufacturer. Identify such causes and remove them is the task of the processing management. The on-line control system consists of periodic inspection of every month produced item. Once any of those items is quali ed as not t, it is admitted that a change in the fraction of the items occurred, and then the process is stopped for adjustments. This work is an extension of Quinino & Ho (2010) and has as objective main to make the monitoramento in a process through the control on-line of quality for the number of non-conformities about the inspected item. The strategy of decision to verify if the process is under control, is directly associated to the limits of the graphic control of non-conformities of the process. A policy of preventive adjustments is incorporated in order to enlarge the conforming fraction of the process. With the help of the R software, a sensibility analysis of the proposed model is done showing in which situations it is most interesting to execute the preventive adjustment

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The central objective of a study Non-Homogeneous Markov Chains is the concept of weak and strong ergodicity. A chain is weak ergodic if the dependence on the initial distribution vanishes with time, and it is strong ergodic if it is weak ergodic and converges in distribution. Most theoretical results on strong ergodicity assume some knowledge of the limit behavior of the stationary distributions. In this work, we collect some general results on weak and strong ergodicity for chains with space enumerable states, and also study the asymptotic behavior of the stationary distributions of a particular type of Markov Chains with finite state space, called Markov Chains with Rare Transitions

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