798 resultados para Stocks -- Decision making.


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

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Although praised for their rationality, humans often make poor decisions, even in simple situations. In the repeated binary choice experiment, an individual has to choose repeatedly between the same two alternatives, where a reward is assigned to one of them with fixed probability. The optimal strategy is to perseverate with choosing the alternative with the best expected return. Whereas many species perseverate, humans tend to match the frequencies of their choices to the frequencies of the alternatives, a sub-optimal strategy known as probability matching. Our goal was to find the primary cognitive constraints under which a set of simple evolutionary rules can lead to such contrasting behaviors. We simulated the evolution of artificial populations, wherein the fitness of each animat (artificial animal) depended on its ability to predict the next element of a sequence made up of a repeating binary string of varying size. When the string was short relative to the animats' neural capacity, they could learn it and correctly predict the next element of the sequence. When it was long, they could not learn it, turning to the next best option: to perseverate. Animats from the last generation then performed the task of predicting the next element of a non-periodical binary sequence. We found that, whereas animats with smaller neural capacity kept perseverating with the best alternative as before, animats with larger neural capacity, which had previously been able to learn the pattern of repeating strings, adopted probability matching, being outperformed by the perseverating animats. Our results demonstrate how the ability to make predictions in an environment endowed with regular patterns may lead to probability matching under less structured conditions. They point to probability matching as a likely by-product of adaptive cognitive strategies that were crucial in human evolution, but may lead to sub-optimal performances in other environments.

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The management of health services is a complex administrative practice due to the breadth of the field of health and the need to reconcile individual, corporate and collective interests that are not always convergent. In this context, the evaluation needs to have specific characteristics in order to fulfill its role. The scope of this study was to establish the characteristics that the evaluation for the management of health services should have to contribute to decision-making. Usefulness, opportunity, feasibility, reliability, objectivity and directionality represent the set of principles upon which the evaluation should be based. Evaluations should lead to decisions that guarantee not only their efficiency and effectiveness but also their implementation. The evaluation process should ensure that decisions involve all stakeholders in order to render the implementation of decisions feasible, and take into account the health needs of the population and the goals set for the services. The scope of this article is to elicit a debate among different stakeholders in the evaluation in the hope that it can contribute to the reflection on the real usefulness of evaluations in which the political component in management has been increasingly prevalent.

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The extraction of information about neural activity timing from BOLD signal is a challenging task as the shape of the BOLD curve does not directly reflect the temporal characteristics of electrical activity of neurons. In this work, we introduce the concept of neural processing time (NPT) as a parameter of the biophysical model of the hemodynamic response function (HRF). Through this new concept we aim to infer more accurately the duration of neuronal response from the highly nonlinear BOLD effect. The face validity and applicability of the concept of NPT are evaluated through simulations and analysis of experimental time series. The results of both simulation and application were compared with summary measures of HRF shape. The experiment that was analyzed consisted of a decision-making paradigm with simultaneous emotional distracters. We hypothesize that the NPT in primary sensory areas, like the fusiform gyrus, is approximately the stimulus presentation duration. On the other hand, in areas related to processing of an emotional distracter, the NPT should depend on the experimental condition. As predicted, the NPT in fusiform gyrus is close to the stimulus duration and the NPT in dorsal anterior cingulate gyrus depends on the presence of an emotional distracter. Interestingly, the NPT in right but not left dorsal lateral prefrontal cortex depends on the stimulus emotional content. The summary measures of HRF obtained by a standard approach did not detect the variations observed in the NPT. Hum Brain Mapp, 2012. (C) 2010 Wiley Periodicals, Inc.

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Objective: this study investigated the feelings of women regarding end-of-life decision making after ultrasound diagnosis of a lethal fetal malformation. The aim of this study was to present the decision making process of women that chose for pregnancy termination and to present selected speeches of women about their feelings. Design: open psychological interviews conducted by a psychologist immediately after the diagnosis of fetal malformation by ultrasound. Analysis of the results was performed through a content analysis technique. Setting: the study was carried out at a public university hospital in Brazil. Participants: 249 pregnant women who had received the diagnosis of a severe lethal fetal malformation. Findings: fetal anencephaly was the most frequent anomaly detected in 135 cases (54.3%). Termination of pregnancy was decided by 172 (69.1%) patients and legally authorised by the judiciary (66%). The reason for asking for termination was to reduce suffering in all of them. In the 77 women who chose not to terminate pregnancy (30.9%), the reasons were related to feelings of guilt (74%). Key conclusions: the results support the importance of psychological counselling for couples when lethal fetal malformation is diagnosed. The act of reviewing moral and cultural values and elements of the unconscious provides assurance in the decision-making process and mitigates the risk of emotional trauma and guilt that can continue long after the pregnancy is terminated. (C) 2011 Elsevier Ltd. All rights reserved.

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Colorectal cancer (CRC) is the most common tumour type in both sexes combined in Western countries. Although screening programmes including the implementation of faecal occult blood test and colonoscopy might be able to reduce mortality by removing precursor lesions and by making diagnosis at an earlier stage, the burden of disease and mortality is still high. Improvement of diagnostic and treatment options increased staging accuracy, functional outcome for early stages as well as survival. Although high quality surgery is still the mainstay of curative treatment, the management of CRC must be a multi-modal approach performed by an experienced multi-disciplinary expert team. Optimal choice of the individual treatment modality according to disease localization and extent, tumour biology and patient factors is able to maintain quality of life, enables long-term survival and even cure in selected patients by a combination of chemotherapy and surgery. Treatment decisions must be based on the available evidence, which has been the basis for this consensus conference-based guideline delivering a clear proposal for diagnostic and treatment measures in each stage of rectal and colon cancer and the individual clinical situations. This ESMO guideline is recommended to be used as the basis for treatment and management decisions.

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A common interest in gene expression data analysis is to identify from a large pool of candidate genes the genes that present significant changes in expression levels between a treatment and a control biological condition. Usually, it is done using a statistic value and a cutoff value that are used to separate the genes differentially and nondifferentially expressed. In this paper, we propose a Bayesian approach to identify genes differentially expressed calculating sequentially credibility intervals from predictive densities which are constructed using the sampled mean treatment effect from all genes in study excluding the treatment effect of genes previously identified with statistical evidence for difference. We compare our Bayesian approach with the standard ones based on the use of the t-test and modified t-tests via a simulation study, using small sample sizes which are common in gene expression data analysis. Results obtained report evidence that the proposed approach performs better than standard ones, especially for cases with mean differences and increases in treatment variance in relation to control variance. We also apply the methodologies to a well-known publicly available data set on Escherichia coli bacterium.

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Many engineering sectors are challenged by multi-objective optimization problems. Even if the idea behind these problems is simple and well established, the implementation of any procedure to solve them is not a trivial task. The use of evolutionary algorithms to find candidate solutions is widespread. Usually they supply a discrete picture of the non-dominated solutions, a Pareto set. Although it is very interesting to know the non-dominated solutions, an additional criterion is needed to select one solution to be deployed. To better support the design process, this paper presents a new method of solving non-linear multi-objective optimization problems by adding a control function that will guide the optimization process over the Pareto set that does not need to be found explicitly. The proposed methodology differs from the classical methods that combine the objective functions in a single scale, and is based on a unique run of non-linear single-objective optimizers.

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The studies in the present thesis focus on post-decision processes using the theoretical framework of Differentiation and Consolidation Theory. This thesis consists of three studies. In all these studies, pre-decision evaluations are compared with post-decision evaluations in order to explore differences in evaluations of decision alternatives before and after a decision. The main aim of the studies was to describe and gain a clearer and better understanding of how people re-evaluate information, following a decision for which they have experienced the decision and outcome. The studies examine how the attractiveness evaluations of important attributes are restructured from the pre-decision to the post-decision phase; particularly restructuring processes of value conflicts. Value conflict attributes are those in which information speaks against the chosen alternative in a decision. The first study investigates an important real-life decision and illustrates different post-decision (consolidation) processes following the decision. The second study tests whether decisions with value conflicts follow the same consolidation (post-decision restructuring) processes when the conflict is controlled experimentally, as in earlier studies of less controlled real-life decisions. The third study investigates consolidation and value conflicts in decisions in which the consequences are controlled and of different magnitudes. The studies in the present thesis have shown how attractiveness restructuring of attributes in conflict occurs in the post-decision phase. Results from the three studies indicated that attractiveness restructuring of attributes in conflict was stronger for important real-life decisions (Study 1) and in situations in which real consequences followed a decision (Study 3) than in more controlled, hypothetical decision situations (Study 2). Finally, some proposals for future research are suggested, including studies of the effects of outcomes and consequences on consolidation of prior decisions and how a decision maker’s involvement affects his or her pre- and post-decision processes.

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Programa de Doctorado: Sistemas Inteligentes y Aplicaciones Numéricas en Ingeniería

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The general objective of this research is to explore theories and methodologies of sustainability indicators, environmental management and decision making disciplines with the operational purpose of producing scientific, robust and relevant information for supporting system understanding and decision making in real case studies. Several tools have been applied in order to increase the understanding of socio-ecological systems as well as providing relevant information on the choice between alternatives. These tools have always been applied having in mind the complexity of the issues and the uncertainty tied to the partial knowledge of the systems under study. Two case studies with specific application to performances measurement (environmental performances in the case of the K8 approach and sustainable development performances in the case of the EU Sustainable Development Strategy) and a case study about the selection of sustainable development indicators amongst Municipalities in Scotland, are discussed in the first part of the work. In the second part of the work, the common denominator among subjects consists in the application of spatial indices and indicators to address operational problems in land use management within the territory of the Ravenna province (Italy). The main conclusion of the thesis is that a ‘perfect’ methodological approach which always produces the best results in assessing sustainability performances does not exist. Rather, there is a pool of correct approaches answering different evaluation questions, to be used when methodologies fit the purpose of the analysis. For this reason, methodological limits and conceptual assumptions as well as consistency and transparency of the assessment, become the key factors for assessing the quality of the analysis.