957 resultados para Marginal structural model


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Nachdem für das Schulfach Musik mit dem Kompetenzmodell „Musik wahrnehmen und kontextualisieren" ein erstes empirisch validiertes Kompetenzmodell vorliegt (Jordan et al., 2012), soll mit dieser Studie in Form eines theoriebasierten Modells musikpraktischer Kompetenz der erste Schritt zur empirischen Modellierung eines weiteren Bereichs, nämlich des musikpraktischen, vorgenommen werden. (DIPF/Orig.)

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Heparin, a sulfated polysaccharide, was the first compound used as an anticoagulant and antithrombotic agent. Due to their structural characteristics, also has great potential anti-inflammatory, though such use is limited in inflammation because of their marked effects on coagulation. The occurrence of heparin-like compounds that exhibit anticoagulant activity decreased in aquatic invertebrates, such as crab Goniopsis cruentata, sparked interest for the study of such compounds as anti-inflammatory drugs. Therefore, the objective of this study was to evaluate the potential modulator of heparin-like compound extracted from Goniopsis cruentata in inflammatory events, coagulation, and to evaluate some aspects of its structure. The heparin-type compound had a high degree of N-sulphation in its structure, being able to reduce leukocyte migration into the peritoneal cavity at lower doses compared to heparin and diclofenac sodium (anti-inflammatory commercial). Furthermore, it was also able to inhibit the production of nitric oxide and tumor necrosis factor alpha by activated macrophages, inhibited the activation of the enzyme neutrophil elastase in low concentrations and showed a lower anticoagulant effect in high doses as compared to porcine mucosal heparin. Because of these observations, the compound extracted from crab Goniopsis cruentata can be used as a structural model for future anti-inflammatory agents

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In recent years the heparin has been the subject of several studies that aim to expand its use as a therapeutic agent, due to its ability to modulate the activity of various proteins that play important roles in the regulation of pathophysiological processes. In several experiments and preclinical trials, heparin has demonstrated an anti-inflammatory role. However, its clinical use is limited, due to its strong anticoagulant activity and hemorrhagic complications. For this reason, considerable efforts have been employed in discovery of heparin analogous (heparinoid) with reduced side effects, that retain the anti-inflammatory properties of heparin. In this context, a heparinoid obtained from the head of Litopenaeus vannamei shrimp, which presents a structural similarity to heparin, showed, in previous studies, anti-inflammatory activity in a model of acute peritonitis with reduced anticoagulant effect in vitro and low hemorrhagic activity. Thus, the present work had as objective to evaluate the effect the heparinoid of the cephalothorax of gray shrimp on the acute inflammatory response in different times (3 or 6 hours after the induction of inflammatory stimulus), using the model of acute peritonitis induced in mice. It was also analyzed the HL effect over the activity of elastase, an enzyme involved in leukocyte recruitment. Furthermore to check if the different doses of heparin and heparinoid change the hemostatic balance in vivo, was assessed the effect of these compounds on the plasma clotting time in animals submitted to inflammation. The results show that in 3 hours, all doses of heparinoid were able to prevent efficiently in the acute inflammatory process without any anticoagulant effects, unlike the extrapolation dose of heparin, which has induced a large hemorrhage due its high anticoagulant activity. However, 6 hours after induction of inflammation, only the dosages of 0.1 and 1.0 μg/Kg of heparin and 1.0 μg/Kg of heparinoid kept anti-migratory effect, without changing of the hemostatic balance. These results indicate that the anti-migratory effect of theses compounds depends on the dosage and time of inflammatory stimulus. The HL and heparin were also able to inhibit the activity of the enzyme elastase. The discovery of this bioactive compound in the cephalothorax of shrimps can arouse great interest in biotechnology, since this compound could be useful as a structural model interesting for the development of new therapeutic agents for peritonitis

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This thesis work deals with a mathematical description of flow in polymeric pipe and in a specific peristaltic pump. This study involves fluid-structure interaction analysis in presence of complex-turbulent flows treated in an arbitrary Lagrangian-Eulerian (ALE) framework. The flow simulations are performed in COMSOL 4.4, as 2D axial symmetric model, and ABAQUS 6.14.1, as 3D model with symmetric boundary conditions. In COMSOL, the fluid and structure problems are coupled by monolithic algorithm, while ABAQUS code links ABAQUS CFD and ABAQUS Standard solvers with single block-iterative partitioned algorithm. For the turbulent features of the flow, the fluid model in both codes is described by RNG k-ϵ. The structural model is described, on the basis of the pipe material, by Elastic models or Hyperelastic Neo-Hookean models with Rayleigh damping properties. In order to describe the pulsatile fluid flow after the pumping process, the available data are often defective for the fluid problem. Engineering measurements are normally able to provide average pressure or velocity at a cross-section. This problem has been analyzed by McDonald's and Womersley's work for average pressure at fixed cross section by Fourier analysis since '50, while nowadays sophisticated techniques including Finite Elements and Finite Volumes exist to study the flow. Finally, we set up peristaltic pipe simulations in ABAQUS code, by using the same model previously tested for the fl uid and the structure.

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In recent decades the public sector comes under pressure in order to improve its performance. The use of Information Technology (IT) has been a tool increasingly used in reaching that goal. Thus, it has become an important issue in public organizations, particularly in institutions of higher education, determine which factors influence the acceptance and use of technology, impacting on the success of its implementation and the desired organizational results. The Technology Acceptance Model - TAM was used as the basis for this study and is based on the constructs perceived usefulness and perceived ease of use. However, when it comes to integrated management systems due to the complexity of its implementation,organizational factors were added to thus seek further explanation of the acceptance of such systems. Thus, added to the model five TAM constructs related to critical success factors in implementing ERP systems, they are: support of top management, communication, training, cooperation, and technological complexity (BUENO and SALMERON, 2008). Based on the foregoing, launches the following research problem: What factors influence the acceptance and use of SIE / module academic at the Federal University of Para, from the users' perception of teachers and technicians? The purpose of this study was to identify the influence of organizational factors, and behavioral antecedents of behavioral intention to use the SIE / module academic UFPA in the perspective of teachers and technical users. This is applied research, exploratory and descriptive, quantitative with the implementation of a survey, and data collection occurred through a structured questionnaire applied to a sample of 229 teachers and 30 technical and administrative staff. Data analysis was carried out through descriptive statistics and structural equation modeling with the technique of partial least squares (PLS). Effected primarily to assess the measurement model, which were verified reliability, convergent and discriminant validity for all indicators and constructs. Then the structural model was analyzed using the bootstrap resampling technique like. In assessing statistical significance, all hypotheses were supported. The coefficient of determination (R ²) was high or average in five of the six endogenous variables, so the model explains 47.3% of the variation in behavioral intention. It is noteworthy that among the antecedents of behavioral intention (BI) analyzed in this study, perceived usefulness is the variable that has a greater effect on behavioral intention, followed by ease of use (PEU) and attitude (AT). Among the organizational aspects (critical success factors) studied technological complexity (TC) and training (ERT) were those with greatest effect on behavioral intention to use, although these effects were lower than those produced by behavioral factors (originating from TAM). It is pointed out further that the support of senior management (TMS) showed, among all variables, the least effect on the intention to use (BI) and was followed by communications (COM) and cooperation (CO), which exert a low effect on behavioral intention (BI). Therefore, as other studies on the TAM constructs were adequate for the present research. Thus, the study contributed towards proving evidence that the Technology Acceptance Model can be applied to predict the acceptance of integrated management systems, even in public. Keywords: Technology

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Dissertação de Mestrado apresentada ao Instituto Superior de Psicologia Aplicada para obtenção de grau de Mestre na especialidade de Psicologia Clínica.

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The present study aims to investigate the constructs of Technological Readiness Index (TRI) and the Expectancy Disconfirmation Theory (EDT) as determinants of satisfaction and continuance intention use in e-learning services. Is proposed a theoretical model that seeks to measure the phenomenon suited to the needs of public organizations that offer distance learning course with the use of virtual platforms for employees. The research was conducted from a quantitative analytical approach, via online survey in a sample of 343 employees of 2 public organizations in RN who have had e-learning experience. The strategy of data analysis used multivariate analysis techniques, including structural equation modeling (SEM), operationalized by AMOS© software. The results showed that quality, quality disconfirmation, value and value disconfirmation positively impact on satisfaction, as well as disconfirmation usability, innovativeness and optimism. Likewise, satisfaction proved to be decisive for the purpose of continuance intention use. In addition, technological readiness and performance are strongly related. Based on the structural model found by the study, public organizations can implement e-learning services for employees focusing on improving learning and improving skills practiced in the organizational environment

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Loading of the replicative ring helicase onto the origin of replication (oriC) is the final outcome of a well coordinated series of events that collectively constitute a primosomal cascade. Once the ring helicase is loaded, it recruits the primase and signals the switch to the polymerization mode. The transient nature of the helicase-primase (DnaB-DnaG) interaction in the Escherichia coli system has hindered our efforts to elucidate its structure and function. Taking advantage of the stable DnaB-DnaG complex in Bacillus stearothermophilus, we have reviewed conflicting mutagenic data from other bacterial systems and shown that DnaG interacts with the flexible linker that connects the N- and C-terminal domains of DnaB. Furthermore, atomic force microscopy (AFM) imaging experiments show that binding of the primase to the helicase induces predominantly a 3-fold symmetric morphology to the hexameric ring. Overall, three DnaG molecules appear to interact with the hexameric ring helicase but a small number of complexes with two and even one DnaG molecule bound to DnaB were also detected. The structural/functional significance of these data is discussed and a speculative structural model for this complex is suggested.

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This dissertation investigates customer behavior modeling in service outsourcing and revenue management in the service sector (i.e., airline and hotel industries). In particular, it focuses on a common theme of improving firms’ strategic decisions through the understanding of customer preferences. Decisions concerning degrees of outsourcing, such as firms’ capacity choices, are important to performance outcomes. These choices are especially important in high-customer-contact services (e.g., airline industry) because of the characteristics of services: simultaneity of consumption and production, and intangibility and perishability of the offering. Essay 1 estimates how outsourcing affects customer choices and market share in the airline industry, and consequently the revenue implications from outsourcing. However, outsourcing decisions are typically endogenous. A firm may choose whether to outsource or not based on what a firm expects to be the best outcome. Essay 2 contributes to the literature by proposing a structural model which could capture a firm’s profit-maximizing decision-making behavior in a market. This makes possible the prediction of consequences (i.e., performance outcomes) of future strategic moves. Another emerging area in service operations management is revenue management. Choice-based revenue systems incorporate discrete choice models into traditional revenue management algorithms. To successfully implement a choice-based revenue system, it is necessary to estimate customer preferences as a valid input to optimization algorithms. The third essay investigates how to estimate customer preferences when part of the market is consistently unobserved. This issue is especially prominent in choice-based revenue management systems. Normally a firm only has its own observed purchases, while those customers who purchase from competitors or do not make purchases are unobserved. Most current estimation procedures depend on unrealistic assumptions about customer arriving. This study proposes a new estimation methodology, which does not require any prior knowledge about the customer arrival process and allows for arbitrary demand distributions. Compared with previous methods, this model performs superior when the true demand is highly variable.

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Objective: Some studies have suggested that school engagement can be an ally in the prevention of psychosocial and occupational risks, to which students are exposed daily. The aim of this study is to estimate the impact of emotional, behavioral, and cognitive engagement on burnout syndrome among pharmacy undergraduate students. Methods: A total of 363 students enrolled in the pharmacy undergraduate program in the College of Pharmaceutical Sciences at Sao Paulo State University’s Araraquara Campus (UNESP) participated, 78.0% of whom were female. Mean age was 20.3 (SD = 2.7) years. The Maslach Burnout Inventory for students (MBI-SS) and the University Students School Engagement Inventory (USEI) were used. Confirmatory factor analysis was performed to assess the psychometric properties of the instruments. The data were included in a structural equation model in which burnout was considered the central construct. The impact of school engagement on burnout was based on the statistical significance of causal paths (β) evaluated by z tests (α = 5%). Results: The psychometric properties of the MBI-SS and USEI were adequate and the structural model also presented an adequate fit. Behavioral engagement (β = −0.56) and the emotional engagement (β = −0.71) explained 81.0% of burnout variability in the sample. Cognitive engagement was not found to contribute significantly. This data provides evidence of the impact of school engagement on burnout that can be used by educators and policymakers in charge of educational process. Conclusion: School engagement presented inverse and significant influence on burnout syndrome among pharmacy students.

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Dissertação de Mestrado apresentada ao Instituto Superior de Psicologia Aplicada para obtenção de grau de Mestre na especialidade de Psicologia Clínica.

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Dissertação de Mestrado, Contabilidade, Faculdade de Economia, Universidade do Algarve, 2016

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The present work reports some experimental results on the electrical AC behaviour of metal-undoped diamond Schottky diodes fabricated with a free-standing MPCVD diamond film (5 mum thick). The metals are gold for the ohmic contact and aluminium for the rectifier. The capacitance and loss tangent vs, frequency shows that capacitance presents a relaxation maximum at frequencies near 10 kHz at room temperature. Although the simple model (small equivalent circuit) can justify the values for the relaxation, it cannot justify the departure from the Debye model, also verified in the Cole-Cole plot. Taking into account the existence of traps in the depletion region, a best fit to the experimental results was obtained. The difference between the Fermi level and the band edge of 0.2-0.3 eV is in agreement with the activation energy found from the loss tangent analysis. The capacitance with applied voltage (Mott-Schottky plots) gives a defect density of 10(16) cm(-3) with contact potentials near 0.5 V and the profile of defect density obtained shows a major density (approx. 10(17) cm(-3)) in a layer with a thickness less than 50 nm from the junction, decreasing by one order of magnitude with increasing distance. Finally a structural model is proposed to explain the AC behaviour found. (C) 2001 Elsevier Science B.V. All rights reserved.

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The occurrence of bioactive compounds in marine organisms comes awaking the interest of the pharmaceutical industry. Heparin, a sulfated polysaccharide which presence was already identified in several marine invertebrates, is very attractive due its remarkable functional versatility. Besides to intervene in blood coagulation, this molecule has a great anti-inflammatory potential. However, its strong anticoagulant activity difficult the clinical exploitation of its anti-inflammatory properties. Thus, the aims of this work were to evaluate the effect of a heparin-like compound (heparinoid), isolated from the cephalotorax of the Litopenaeus vannamei shrimp, on the inflammatory response, hemostasia and synthesis of antithrombotic heparan sulfate by endothelial cells, besides studying some aspects concerning its structure. The purified heparinoid was structurally characterized following an analytical boarding, involving electrophoresis and chromatography. The structural analysis have shown that this compound possess a high content of glucuronic acid residues and disulfated disaccharide units. In contrast to mammalian heparin, the heparinoid was incapable to stimulate the synthesis of heparan sulfate by endothelial cells in the tested concentrations, beyond to show reduced anticoagulant activity and hemorrhagic effect. In a model of acute inflammation, the compound isolated from the shrimp reduced more than 50% of the cellular infiltration. Besides reduce the activity of MMP-9 and proMMP-2 of the peritoneal lavage of inflamed animals, the heparinoid also reduced the activity of MMP-9 secreted by activated human leukocytes. These results demonstrate the potential of heparinoid from L. vannamei to intervene in the inflammatory response. For possessing reduced anticoagulant activity and hemorrhagic effect, this compound can serve as a structural model to direct the development of more specific therapeutical agents to the treatment of inflammatory diseases

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OBJECTIVE: In the majority of studies, the effect of physical activity (PA) on cardiovascular disease (CVD) and mortality is estimated at a single time point. The impact of long-term PA is likely to differ. Our study objective was to estimate the effect of long-term adult-life PA compared with long-term inactivity on the risk of incident CVD, all-cause mortality and CVD-attributable mortality. DESIGN: Observational cohort study. SETTING: Framingham, MA, USA. PATIENTS: 4729 Framingham Heart Study participants who were alive and CVD-free in 1956. EXPOSURES: PA was measured at three visits over 30 years along with a variety of risk factors for CVD. Cumulative PA was defined as long-term active versus long-term inactive. MAIN OUTCOME MEASURES: Incident CVD, all-cause mortality and CVD-attributable mortality. RESULTS: During 40 years of follow-up there were 2594 cases of incident CVD, 1313 CVD-attributable deaths and 3521 deaths. Compared with long-term physical inactivity, the rate ratio of long-term PA was 0.95 (95% CI 0.84 to 1.07) for CVD, 0.81 (0.71 to 0.93) for all-cause mortality and 0.83 (0.72 to 0.97) for CVD-attributable mortality. Assessment of effect modification by sex suggests greater protective effect of long-term PA on CVD incidence (p value for interaction=0.004) in men (0.79 (0.66 to 0.93)) than in women (1.15 (0.97 to 1.37)). CONCLUSIONS: Cumulative long-term PA has a protective effect on incidence of all-cause and CVD-attributable mortality compared with long-term physical inactivity. In men, but not women, long-term PA also appears to have a protective effect on incidence of CVD.