989 resultados para behavioral models
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The study aims to identify the factors that influence the behavior intention to adopt an academic Information System (SIE), in an environment of mandatory use, applied in the procurement process at the Federal University of Pará (UFPA). For this, it was used a model of innovation adoption and technology acceptance (TAM), focused in attitudes and intentions regarding the behavior intention. The research was conducted a quantitative survey, through survey in a sample of 96 administrative staff of the researched institution. For data analysis, it was used structural equation modeling (SEM), using the partial least squares method (Partial Least Square PLS-PM). As to results, the constructs attitude and subjective norms were confirmed as strong predictors of behavioral intention in a pre-adoption stage. Despite the use of SIE is required, the perceived voluntariness also predicts the behavior intention. Regarding attitude, classical variables of TAM, like as ease of use and perceived usefulness, appear as the main influence of attitude towards the system. It is hoped that the results of this study may provide subsidies for more efficient management of the process of implementing systems and information technologies, particularly in public universities
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Parkinson's disease (PD) is one of the most common neurodegenerative brain disorders and is characterized primarily by a progressive degeneration of dopaminergic neurons nigroestriatais. The main symptoms of this disease are motor alterations (bradykinesia, rigidity, tremor at rest), which can be highly disabling in advanced stages of the condition. However, there are symptomatic manifestations other than motor impairment, such as changes in cognition, mood and sensory systems. Animal models that attempt to mimic clinical features of PD have been used to understand the behavioral and neural mechanisms underlying neurophysiological disturbance of this disease. However, most models promote an intense and immediate motor impairment, consistent with advanced stages of the disease, invalidating these studies for the evaluation of its progressive nature. The administration of reserpine (a monoamine depletor) in rodents has been considered an animal model for studying PD. Recently we found that reserpine (in doses lower than those usually employed to produce the motor symptoms) promotes a memory deficit in an aversive discrimination task, without changing the motor activity. It was suggested that the administration of this drug in low doses can be useful for the study of memory deficits found in PD. Corroborating this data, in another study, acute subcutaneous administration of reserpine, while preserving motor function, led to changes in emotional context-related (but not neutral) memory tasks. The goal of this research was to study the cognitive and motor deficits in rats repeatedly treated with low doses of reserpine, as a possible model that simulates the progressive nature of the PD. For this purpose, 5-month-old male Wistar rats were submitted to a repeated treatment with vehicle or different doses of reserpine on alternate days. Cognitive and motor parameters and possible changes in neuronal function were evaluated during treatment. The main findings were: repeated administration of 0.1 mg / kg of reserpine in rats is able to induce the gradual appearance of motor signs compatible with progressive features found in patients with PD; an increase in striatal levels of oxidative stress and changes in the concentrations of glutamate in the striatum were observed five days after the end of treatment; in animals repeatedly-treated with 0. 1 mg/kg, cognitive deficits were observed only after the onset of motor symptoms, but not prior to the onset of these symptoms; 0.2 mg / kg reserpine repeated treatment has jeopardized the cognitive assessment due to the presence of severe motor deficits. Thus, we suggest that the protocol of treatment with reserpine used in this work is a viable alternative for studies of the progressive appearance of parkinsonian signs in rats, especially concerning motor symptoms. As for the cognitive symptoms, we suggest that more studies are needed, possibly using other behavioral models, and / or changing the treatment regimen
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Cochlear root neurons (CRNs) are involved in the acoustic startle reflex, which is widely used in behavioral models of sensorimotor integration. A short-latency component of this reflex, the auricular reflex, promotes pinna movements in response to unexpected loud sounds. However, the pathway involved in the auricular component of the startle reflex is not well understood. We hypothesized that the auricular reflex is mediated by direct and indirect inputs from CRNs to the motoneurons responsible for pinna movement, which are located in the medial subnucleus of the facial motor nucleus (Mot7). To assess whether there is a direct connection between CRNs and auricular motoneurons in the rat, two neuronal tracers were used in conjunction: biotinylated dextran amine, which was injected into the cochlear nerve root, and Fluoro-Gold, which was injected into the levator auris longus muscle. Under light microscopy, close appositions were observed between axon terminals of CRNs and auricular motoneurons. The presence of direct synaptic contact was confirmed at the ultrastructural level. To confirm the indirect connection, biotinylated dextran amine was injected into the auditory-responsive portion of the caudal pontine reticular nucleus, which receives direct input from CRNs. The results confirm that the caudal pontine reticular nucleus also targets the Mot7 and that its terminals are concentrated in the medial subnucleus. Therefore, it is likely that CRNs innervate auricular motoneurons both directly and indirectly, suggesting that these connections participate in the rapid auricular reflex that accompanies the acoustic startle reflex. © 2008 Wiley-Liss, Inc.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The purpose of this work is to propose a structure for simulating power systems using behavioral models of nonlinear DC to DC converters implemented through a look-up table of gains. This structure is specially designed for converters whose output impedance depends on the load current level, e.g. quasi-resonant converters. The proposed model is a generic one whose parameters can be obtained by direct measuring the transient response at different operating points. It also includes optional functionalities for modeling converters with current limitation and current sharing in paralleling characteristics. The pusposed structured also allows including aditional characteristics of the DC to DC converter as the efficency as a function of the input voltage and the output current or overvoltage and undervoltage protections. In addition, this proposed model is valid for overdamped and underdamped situations.
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Various transcription factors act as nuclear effectors of the cAMP-dependent signaling pathway. These are the products of three genes in the mouse, CREB, CRE modulator (CREM), and ATF-1. CREM proteins are thought to play important roles within the hypothalamic–pituitary axis and in the control of rhythmic functions in the pineal gland. We have generated CREM-mutant mice and investigated their response in a variety of behavioral tests. CREM-null mice show a drastic increase in locomotion. In contrast to normal mice, the CREM-deficient mice show equal locomotor activity during the circadian cycle. The anatomy of the hypothalamic suprachiasmatic nuclei, the center of the endogenous pacemaker, is normal in mutant mice. Remarkably, CREM mutant mice also elicit a different emotional state, revealed by a lower anxiety in two different behavioral models, but they preserve the conditioned reactiveness to stress. These results demonstrate the high degree of functional specificity of each cAMP-responsive transcription factor in behavioral control.
The spinal biology in humans and animals of pain states generated by persistent small afferent input
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Behavioral models indicate that persistent small afferent input, as generated by tissue injury, results in a hyperalgesia at the site of injury and a tactile allodynia in areas adjacent to the injury site. Hyperalgesia reflects a sensitization of the peripheral terminal and a central facilitation evoked by the persistent small afferent input. The allodynia reflects a central sensitization. The spinal pharmacology of these pain states has been defined in the unanesthetized rat prepared with spinal catheters for injection and dialysis. After tissue injury, excitatory transmitters (e.g., glutamate and substance P) acting though N-methyl-d-aspartate (NMDA) and neurokinin 1 receptors initiate a cascade that evokes release of (i) NO, (ii) cyclooxygenase products, and (iii) activation of several kinases. Spinal dialysis show amino acid and prostanoid release after cutaneous injury. Spinal neurokinin 1, NMDA, and non-NMDA receptors enhance spinal prostaglandin E2 release. Spinal prostaglandins facilitate release of spinal amino acids and peptides. Activation by intrathecal injection of receptors on spinal C fiber terminals (μ,/∂ opiate, α2 adrenergic, neuropeptide Y) prevents release of primary afferent peptides and spinal amino acids and blocks acute and facilitated pain states. Conversely, consistent with their role in facilitated processing, NMDA, cyclooxygenase 2, and NO synthase inhibitors act to diminish only hyperalgesia. Importantly, spinal delivery of several of these agents diminishes human injury pain states. This efficacy emphasizes (i) the role of facilitated states in humans, (ii) shows the importance of spinal systems in human pain processing, and (iii) indicates that these preclinical mechanisms reflect processes that regulate the human pain experience.
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O Teste Baseado em Modelos (TBM) emergiu como uma estratégia promissora para minimizar problemas relacionados à falta de tempo e recursos em teste de software e visa verificar se a implementação sob teste está em conformidade com sua especificação. Casos de teste são gerados automaticamente a partir de modelos comportamentais produzidos durante o ciclo de desenvolvimento de software. Entre as técnicas de modelagem existentes, Sistemas de Transição com Entrada/Saída (do inglês, Input/Output Transition Systems - IOTSs), são modelos amplamente utilizados no TBM por serem mais expressivos do que Máquinas de Estado Finito (MEFs). Apesar dos métodos existentes para geração de testes a partir de IOTSs, o problema da seleção de casos de testes é um tópico difícil e importante. Os métodos existentes para IOTS são não-determinísticos, ao contrário da teoria existente para MEFs, que fornece garantia de cobertura completa com base em um modelo de defeitos. Esta tese investiga a aplicação de modelos de defeitos em métodos determinísticos de geração de testes a partir de IOTSs. Foi proposto um método para geração de conjuntos de teste com base no método W para MEFs. O método gera conjuntos de teste de forma determinística além de satisfazer condições de suficiência de cobertura da especificação e de todos os defeitos do domínio de defeitos definido. Estudos empíricos avaliaram a aplicabilidade e eficácia do método proposto: resultados experimentais para analisar o custo de geração de conjuntos de teste utilizando IOTSs gerados aleatoriamente e um estudo de caso com especificações da indústria mostram a efetividade dos conjuntos gerados em relação ao método tradicional de Tretmans.
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Objective: Our aim was to determine if insomnia severity, dysfunctional beliefs about sleep, and depression predicted sleep-related safety behaviors. Method: Standard sleep-related measures (such as the Insomnia Severity Index; the Dysfunctional Beliefs About Sleep scale; the Depression, Anxiety, and Stress Scale; and the Sleep-Related Behaviors Questionnaire) were administered. Additionally, 14 days of sleep diary (Pittsburg Sleep Diary) data and actual use of sleep-related behaviors were collected. Results: Regression analysis revealed that dysfunctional beliefs about sleep predicted sleep-related safety behaviors. Insomnia severity did not predict sleep-related safety behaviors. Depression accounted for the greatest amount of unique variance in the prediction of safety behaviors, followed by dysfunctional beliefs. Exploratory analysis revealed that participants with higher levels of depression used more sleep-related behaviors and reported greater dysfunctional beliefs about their sleep. Conclusion: The findings underlie the significant influence that dysfunctional beliefs have on individuals' behaviors. Moreover, the results suggest that depression may need to be considered as an explicit component of cognitive-behavioral models of insomnia. (c) 2006 Elsevier Inc. All rights reserved.
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Apesar de várias evidências do potencial terapêutico dos óleos essenciais em diversas patologias, inclusive em transtornos mentais, os estudos científicos que comprovam esse potencial ainda são escassos. O objetivo deste trabalho foi investigar e comparar de forma sistemática os efeitos dos óleos essenciais de alecrim (Rosmarinus officinalis) e petitgrain (Citrus aurantium L.) em modelos animais com ratos nos seguintes parâmetros: atividade motora, depressão, ansiedade e aprendizado. Método: foram utilizados 297 ratos em todo o estudo, sendo: 54 no piloto 1; 66 no piloto 2; 36 no campo aberto; 36 na esquiva discriminativa; 36 no teste de enterrar esferas; 33 na natação forçada e 36 no experimento de aprendizagem. Os principais resultados revelaram que: ratos tratados com 100mg/kg (i.p.) de óleo essencial de alecrim não apresentaram diferença na atividade motora avaliada em campo aberto (p=0.213 teste de Mann-Whitney), tampouco na aprendizagem da resposta de pressão à barra em caixa de Skinner (p=0.098 teste de Mann-Whitney), comparados aos ratos controles que receberam salina 0,9% (1 mL/kg), porém esse mesmo tratamento foi efetivo em modelos de depressão (p=0.006 teste de Mann-Whitney) e ansiedade (teste de esconder esferas - p=0.003 ANOVA). No que diz respeito ao óleo essencial de petitgrain administrado em ratos na dose de 30mg/kg (i.p.), não observou-se diferença na atividade motora (p=0.795 teste de Mann-Whitney), contudo obteve-se efeito ansiolítico (teste de esconder esferas - p=0.028 ANOVA) e antidepressivo (p=0.001 teste de Mann-Whitney) em relação ao controle. Ademais, o óleo de petitgrain proporcionou uma melhora na aprendizagem (p=0.002 teste de Mann-Whitney) se comparado com os animais do grupo controle e os animais tratados com alecrim. Dessa forma podemos concluir que ambos os óleos estudados (alecrim e petitgrain) apresentaram atividades ansiolítica e antidepressiva nos testes realizados e apenas o óleo de petitgrain produziu efeitos na aprendizagem dos animais.
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The study aims to identify the factors that influence the behavior intention to adopt an academic Information System (SIE), in an environment of mandatory use, applied in the procurement process at the Federal University of Pará (UFPA). For this, it was used a model of innovation adoption and technology acceptance (TAM), focused in attitudes and intentions regarding the behavior intention. The research was conducted a quantitative survey, through survey in a sample of 96 administrative staff of the researched institution. For data analysis, it was used structural equation modeling (SEM), using the partial least squares method (Partial Least Square PLS-PM). As to results, the constructs attitude and subjective norms were confirmed as strong predictors of behavioral intention in a pre-adoption stage. Despite the use of SIE is required, the perceived voluntariness also predicts the behavior intention. Regarding attitude, classical variables of TAM, like as ease of use and perceived usefulness, appear as the main influence of attitude towards the system. It is hoped that the results of this study may provide subsidies for more efficient management of the process of implementing systems and information technologies, particularly in public universities
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A primary goal of context-aware systems is delivering the right information at the right place and right time to users in order to enable them to make effective decisions and improve their quality of life. There are three key requirements for achieving this goal: determining what information is relevant, personalizing it based on the users’ context (location, preferences, behavioral history etc.), and delivering it to them in a timely manner without an explicit request from them. These requirements create a paradigm that we term as “Proactive Context-aware Computing”. Most of the existing context-aware systems fulfill only a subset of these requirements. Many of these systems focus only on personalization of the requested information based on users’ current context. Moreover, they are often designed for specific domains. In addition, most of the existing systems are reactive - the users request for some information and the system delivers it to them. These systems are not proactive i.e. they cannot anticipate users’ intent and behavior and act proactively without an explicit request from them. In order to overcome these limitations, we need to conduct a deeper analysis and enhance our understanding of context-aware systems that are generic, universal, proactive and applicable to a wide variety of domains. To support this dissertation, we explore several directions. Clearly the most significant sources of information about users today are smartphones. A large amount of users’ context can be acquired through them and they can be used as an effective means to deliver information to users. In addition, social media such as Facebook, Flickr and Foursquare provide a rich and powerful platform to mine users’ interests, preferences and behavioral history. We employ the ubiquity of smartphones and the wealth of information available from social media to address the challenge of building proactive context-aware systems. We have implemented and evaluated a few approaches, including some as part of the Rover framework, to achieve the paradigm of Proactive Context-aware Computing. Rover is a context-aware research platform which has been evolving for the last 6 years. Since location is one of the most important context for users, we have developed ‘Locus’, an indoor localization, tracking and navigation system for multi-story buildings. Other important dimensions of users’ context include the activities that they are engaged in. To this end, we have developed ‘SenseMe’, a system that leverages the smartphone and its multiple sensors in order to perform multidimensional context and activity recognition for users. As part of the ‘SenseMe’ project, we also conducted an exploratory study of privacy, trust, risks and other concerns of users with smart phone based personal sensing systems and applications. To determine what information would be relevant to users’ situations, we have developed ‘TellMe’ - a system that employs a new, flexible and scalable approach based on Natural Language Processing techniques to perform bootstrapped discovery and ranking of relevant information in context-aware systems. In order to personalize the relevant information, we have also developed an algorithm and system for mining a broad range of users’ preferences from their social network profiles and activities. For recommending new information to the users based on their past behavior and context history (such as visited locations, activities and time), we have developed a recommender system and approach for performing multi-dimensional collaborative recommendations using tensor factorization. For timely delivery of personalized and relevant information, it is essential to anticipate and predict users’ behavior. To this end, we have developed a unified infrastructure, within the Rover framework, and implemented several novel approaches and algorithms that employ various contextual features and state of the art machine learning techniques for building diverse behavioral models of users. Examples of generated models include classifying users’ semantic places and mobility states, predicting their availability for accepting calls on smartphones and inferring their device charging behavior. Finally, to enable proactivity in context-aware systems, we have also developed a planning framework based on HTN planning. Together, these works provide a major push in the direction of proactive context-aware computing.
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In this thesis, tool support is addressed for the combined disciplines of Model-based testing and performance testing. Model-based testing (MBT) utilizes abstract behavioral models to automate test generation, thus decreasing time and cost of test creation. MBT is a functional testing technique, thereby focusing on output, behavior, and functionality. Performance testing, however, is non-functional and is concerned with responsiveness and stability under various load conditions. MBPeT (Model-Based Performance evaluation Tool) is one such tool which utilizes probabilistic models, representing dynamic real-world user behavior patterns, to generate synthetic workload against a System Under Test and in turn carry out performance analysis based on key performance indicators (KPI). Developed at Åbo Akademi University, the MBPeT tool is currently comprised of a downloadable command-line based tool as well as a graphical user interface. The goal of this thesis project is two-fold: 1) to extend the existing MBPeT tool by deploying it as a web-based application, thereby removing the requirement of local installation, and 2) to design a user interface for this web application which will add new user interaction paradigms to the existing feature set of the tool. All phases of the MBPeT process will be realized via this single web deployment location including probabilistic model creation, test configurations, test session execution against a SUT with real-time monitoring of user configurable metric, and final test report generation and display. This web application (MBPeT Dashboard) is implemented with the Java programming language on top of the Vaadin framework for rich internet application development. The Vaadin framework handles the complicated web communications processes and front-end technologies, freeing developers to implement the business logic as well as the user interface in pure Java. A number of experiments are run in a case study environment to validate the functionality of the newly developed Dashboard application as well as the scalability of the solution implemented in handling multiple concurrent users. The results support a successful solution with regards to the functional and performance criteria defined, while improvements and optimizations are suggested to increase both of these factors.