916 resultados para Functions of complex variables.
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Spanish version available at the Library
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A "second generation" matching-to-sample procedure that minimizes past sources of artifacts involves (1) successive discrimination between sample stimuli, (2) stimulus displays ranging from four to 16 comparisons, (3) variable stimulus locations to avoid unwanted stimulus-location control, and (4) high accuracy levels (e.g., 90% correct on a 16-choice task in which chance accuracy is 6%). Examples of behavioral engineering with experienced capuchin monkeys included four-choice matching problems with video images of monkeys with substantially above-chance matching in a single session and 90% matching within six sessions. Exclusion performance was demonstrated by interspersing non-identical sample-comparison pairs within a baseline of a nine-comparison identity-matching-to-sample procedure with pictures as stimuli. The test for exclusion presented the newly "mapped" stimulus in a situation in which exclusion was not possible. Degradation of matching between physically non-identical forms occurred while baseline identity accuracy was sustained at high levels, thus confirming that Cebus cf. apella is capable of exclusion. Additionally, exclusion performance when baseline matching relations involved non-identical stimuli was shown.
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Do capuchin monkeys respond to photos as icons? Do they discriminate photos of capuchin monkeys' faces? Looking for answers to these questions we trained three capuchin monkeys in simple and conditional discrimination tasks and tested the discriminations when comparison stimuli were partially covered. Three capuchin monkeys experienced in simultaneous simple discrimination and IDMTS were trained with repeated shifts of simple discriminations (RSSD), with four simultaneous choices, and IDMTS (1 s delay, 4 choices) with pictures of known capuchins monkeys' faces. All monkeys did discriminate the pictures in both procedures. Performances in probes with partial masks with one fourth of the stimulus hidden were consistent with baseline level. Errors occurred when a picture similar to the correct one was available among the comparison stimuli, when the covered part was the most distinct, or when pictures displayed the same monkey. Capuchin monkeys do match pictures of capuchin monkeys' faces to the sample. The monkeys treated different pictures of the same monkey as equivalent, suggesting that they respond to the pictures as icons, although this was not true to pictures of other monkeys. Subsequent studies may bring more evidence that capuchin monkeys treat pictures as depictions of real scenes.
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ABSTRACT: Hydrogenation of passion fruit (passiflora edulis) seed oil was carried out with a commercial nickel/silica catalyst under different experimental conditions. The influence of reaction parameters (reaction temperature, hydrogen pressure, amount of catalyst, agitation rate and reaction time) on the response variable (iodine value) was studied using a central composite rotatable design and six center points for replication. Under the experimental conditions used, the model response equations for the iodine value showed good agreement with the experimental results.
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The purpose of this study was to analyze the effect of different exercise programs on the psychological and cognitive functions in patients with Parkinson's disease (PD). Forty-five patients with PD participated in the study. The participants were randomized in three intervention programs: Group-1 (n=15, cognitive-activities), Group-2 (n=15, multimodal exercise) and Group-3 (n=15, exercises for posture and gait). The clinical, psychological and cognitive functions were assessed before and after 4 months of intervention. Univariate analysis did not reveal significant interactions between groups and time (p>0.05). However, univariate analysis for time revealed differences in stress level and memory. Participants showed less physical stress (p<0.01) and overall stress (p < 0.04) and higher performance in episodic declarative memory (p < 0.001) after exercise. These findings suggest that group work with motor or non-motor activities can improve cognitive and psychological functions of patients with PD.
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We discuss the relation between correlation functions of twist-two large spin operators and expectation values of Wilson loops along light-like trajectories. After presenting some heuristic field theoretical arguments suggesting this relation, we compute the divergent part of the correlator in the limit of large 't Hooft coupling and large spins, using a semi-classical world-sheet which asymptotically looks like a GKP rotating string. We show this diverges as expected from the expectation value of a null Wilson loop, namely, as (ln mu(-2))(2). mu being a cut-off of the theory. (C) 2012 Elsevier B.V. All rights reserved.
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We establish general conditions for the unique solvability of nonlinear measure functional differential equations in terms of properties of suitable linear majorants.
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The article investigates complex impulsive systems in which the so-called controlling systems jumps effect emerges. In particular, this research includes the correctness of the solution to the impulsive control system and approximation lemmas. A 3D model example is provided which illustrates the relevance of the considered approach to the study of complex impulsive systems.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The effects of body biometrics on cardiac measurements and description of cardiac anatomy were performed in red-tailed boas (Boa constrictor constrictor) (n = 29) using real-time B-mode ultrasonography. Statistical comparison of measured cardiac metrics according to sex and body measurements demonstrated no significant difference between sexes but a highly significant linear increase between body length and mass and all cardiac metrics.
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The present study investigated the osmotic dehydration (OD) of mangoes cv.Palmer, dehydrated in a sucrose solution with added ascorbic acid (AA), aiming toevaluate the influence of the process variables (sucrose concentration, AA concen-tration and time) on vitamin C, water, sugars and total phenolic compound (TPC)contents by way of an analysis of the effects and the variance of the factors. Thesucrose concentration did not affect the vitamin C content, but the AA concentra-tion in the solution and the process time exerted a positive influence on thisresponse. The addition of AA also presented a significant positive effect on theTPC contents because this vitamin interferes with the quantification of the TPC.On discounting the interferences, no losses of phenolic compounds were found.Impregnation with vitamin C during OD was shown to be effective in obtainingminimally processed mangoes with high nutritional value.
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Pós-graduação em Física - IFT
Influence of morphological variables in photoelastic models with implants submitted to axial loading
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Purpose: This study used 12 photoelastics models with different height and thickness to evaluate if the axial loading of 100N on implants changes the morphology of the photoelastic reflection. Methods: For the photoelastic analysis, the models were placed in a reflection polariscope for observation of the isochromatic fringes patterns. The formation of these fringes resulted from an axial load of 100N applied to the midpoint of the healing abutment attached to the implant with 10.0mm x 3.75mm (Conexão, Sistemas de Próteses, Brazil). The tension in each photoelastic model was monitored, photographed and observed using the software Phothoshop 7.0. For qualitative analysis, the area under the implant apex was measured including the green band of the second order fringe of each model using the software Image Tool. After comparison of the areas, the performance generated by each specimen was defined regarding the axial loading. Results: There were alterations in area with different height and thickness of the photoelastic models. It was observed that the group III (30mm in height) presented the smallest area. Conclusion: There was variation in the size of the areas analyzed for different height and thickness of the models and the morphology of the replica may directly influence the result in researches with photoelastic models.
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The prevalence of anxiety and depression disorders in undergraduate students is high and several variables can be influential. The aim is to verify the predictive value of social skills, sociodemographic variables, and course characteristics for depression and anxiety. A total of 1282 students of a public university, of both sexes and from different years and courses, participated in this study. Screening instruments for depression and anxiety were applied, as well as an instrument investigating social skills and a questionnaire covering socio demographic indicators and course characteristics. The data were analyzed using univariate analysis followed by multiple binary regression analysis in order to define the relevance of these depression and anxiety measures. The rates of anxiety and depression were 19.4% and 3.8%, respectively. The social skills and living situation were predictive of depression, with the social skills and course area (with higher prevalence for the exact and human sciences) remaining in the final model for anxiety. Such data have implications for psychological prevention and intervention with this population.
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Even though the digital processing of documents is increasingly widespread in industry, printed documents are still largely in use. In order to process electronically the contents of printed documents, information must be extracted from digital images of documents. When dealing with complex documents, in which the contents of different regions and fields can be highly heterogeneous with respect to layout, printing quality and the utilization of fonts and typing standards, the reconstruction of the contents of documents from digital images can be a difficult problem. In the present article we present an efficient solution for this problem, in which the semantic contents of fields in a complex document are extracted from a digital image.