78 resultados para instrumental variable
em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Organisms are constantly subjected to stressful stimuli that affect numerous physiological processes and activate the hypothalamo-pituitary-adrenal (HPA) axis, increasing the release of glucocorticoids. Exposure to chronic stress is known to alter basic mechanisms of the stress response. The purpose of the present study was to compare the effect of two different stress paradigms (chronic restraint or variable stress) on behavioral and corticosterone release to a subsequent exposure to stressors. Considering that the HPA axis might respond differently when it is challenged with a novel or a familiar stressor we investigated the changes in the corticosterone levels following the exposure to two stressors: restraint (familiar stress) or forced novelty (novel stress). The changes in the behavioral response were evaluated by measuring the locomotor response to a novel environment. In addition, we examined changes in body, adrenals, and thymus weights in response to the chronic paradigms. Our results showed that exposure to chronic variable stress increased basal plasma corticosterone levels and that both, chronic restraint and variable stresses, promote higher corticosterone levels in response to a novel environment, but not to a challenge restraint stress, as compared to the control (non-stressed) group. Exposure to chronic restraint leads to increased novelty-induced locomotor activity. Furthermore, only the exposure to variable stress reduced body weights. In conclusion, the present results provide additional evidence on how chronic stress affects the organism physiology and point to the importance of the chronic paradigm and challenge stress on the behavioral and hormonal adaptations induced by chronic stress. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
It is shown that, in the two brane time variation model framework, if the hidden brane tension varies according to the phenomenological Eotvos law, the visible brane tension behavior is such that its time derivative is negative in the past and positive after a specific time of cosmological evolution. This behavior is interpreted in terms of a useful mechanical system analog and its relation with the variation of the Newtonian (effective) gravitational constant is explored.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
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.
Resumo:
A novel single-phase voltage source rectifier capable to achieve High-Power-Factor (HPF) for variable speed refrigeration system application, is proposed in this paper. The proposed system is composed by a single-phase high-power-factor boost rectifier, with two cells in interleave connection, operating in critical conduction mode, and employing a soft-switching technique, controlled by a Field Programmable Gate Array (FPGA), associated with a conventional three-phase IGBT bridge inverter (VSI - Voltage Source Inverter), controlled by a Digital Signal Processor (DSP). The soft-switching technique for the input stage is based on zero-current-switching (ZCS) cells. The rectifier's features include the reduction in the input current ripple, the reduction in the output voltage ripple, the use of low stress devices, low volume for the EMI input filter, high input power factor (PF), and low total harmonic distortion (THD) in the input current, in compliance with the EEC61000-3-2 standards. The digital controller for the output stage has been developed using a conventional voltage-frequency control (scalar V/f control), and a simplified stator oriented Vector control, in order to verify the feasibility and performance of the proposed digital controls for continuous temperature control applied at a refrigerator prototype.
Variable-Structure Control Design of Switched Systems With an Application to a DC-DC Power Converter
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Aims: To estimate the prevalence and correlates of cognitive impairment (CI) among the elderly in a general hospital. Methods: A cross-sectional study, including 200 Brazilian inpatients aged 60 years or over, using the Mini Mental State Examination to evaluate CI (dependent variable), and the Geriatric Depression Scale and the Katz and Lawton Index to evaluate basic (BADL) and instrumental activities of daily living (IADL). Results: 56% were women, 29% were dependent for BADL and 77.5% for IADL. The prevalence of CI was 29% and, in the logistic regression, it remained associated with higher age (1 74 years old), number of previous hospitalizations (1 3) and dependency for BADL (being dependent raised the odds of being cognitively impaired). Conclusions: It is essential to train the hospital staff to properly assist these patients, and to orient and support their caregivers. Copyright (C) 2009 S. Karger AG, Basel
Resumo:
OBJETIVO: Analisar os efeitos de seis meses de intervenção de um programa de atividade física sobre os distúrbios neuropsiquiátricos e o desempenho nas atividades instrumentais da vida diária de idosos com Doença de Alzheimer (DA). MÉTODOS: Foram recrutados 20 pacientes nos estágios entre leve e moderado da DA. Segundo o escore clínico de demência (CDR), foram distribuídos em dois grupos: o grupo treinamento (GT), composto por dez mulheres que participaram de um program de exercícios físicos por um período de seis meses, e o grupo controle (GC), composto por dez outras participantes que não realizaram nenhum tipo de intervenção motora estruturada durante o mesmo período. Todas as participantes foram avaliadas por meio do Miniexame do Estado Mental, para obtenção da caracterização cognitiva; Inventário Neuropsiquiátrico, para identificação dos distúrbios neuropsiquiátricos mais prevalentes e Questionário de Atividades Instrumentais de Pfeffer, para verificação do grau de comprometimento funcional. RESULTADOS: Os participantes do GC mostraram uma deterioração tanto no desempenho das atividades instrumentais quanto na intensificação dos distúrbios neuropsiquiátricos, quando comparados os momentos pré e pós-intervenção. CONCLUSÃO: O GT demonstrou uma atenuação da intensificação dos distúrbios neuropsiquiátricos e do desempenho funcional em relação ao grupo sedentário.
Resumo:
O efeito das variáveis independentes: soro desmineralizado em pó (0,0; 1,5 e 3,0 %), cultura láctica (1,0; 2,0 e 3,0 %) e temperatura de tratamento da mistura (85; 90 e 95°C) foi estudado nas respostas consistência sensorial e instrumental do iogurte. A metodologia de superfície de resposta foi usada para efetuar tratamentos estatísticos dos experimentos e desenvolver modelos matemáticos da relação entre as variáveis e as respostas. A consistência instrumental e sensorial apresentaram resultados semelhantes e correlacionáveis entre si, r = 0,65 (p < 0,01), ambas foram maiores quando aumentou-se a temperatura da mistura e diminuiu-se o teor de soro desmineralizado em pó.