934 resultados para search methods
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Cytochrome P450 (CYP450) is a class of enzymes where the substrate identification is particularly important to know. It would help medicinal chemists to design drugs with lower side effects due to drug-drug interactions and to extensive genetic polymorphism. Herein, we discuss the application of the 2D and 3D-similarity searches in identifying reference Structures with higher capacity to retrieve Substrates of three important CYP enzymes (CYP2C9, CYP2D6, and CYP3A4). On the basis of the complementarities of multiple reference structures selected by different similarity search methods, we proposed the fusion of their individual Tanimoto scores into a consensus Tanimoto score (T(consensus)). Using this new score, true positive rates of 63% (CYP2C9) and 81% (CYP2D6) were achieved with false positive rates of 4% for the CYP2C9-CYP2D6 data Set. Extended similarity searches were carried out oil a validation data set, and the results showed that by using the T(consensus) score, not only the area of a ROC graph increased, but also more substrates were recovered at the beginning of a ranked list.
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This paper presents a study carried out with customers with credit card of a large retailer to measure the risk of abandonment of a relationship, when this has already purchase history. Two activities are the most important in this study: the theoretical and methodological procedures. The first step was to the understanding of the problem, the importance of theme and the definition of search methods. The study brings a bibliographic survey comprising several authors and shows that the loyalty of customers is the basis that gives sustainability and profitability for organizations of various market segments, examines the satisfaction as the key to success for achievement and specially for the loyalty of customers. To perform this study were adjusted logistic-linear models and through the test Kolmogorov - Smirnov (KS) and the curve Receiver Operating Characteristic (ROC) selected the best model. Had been used cadastral and transactional data of 100,000 customers of credit card issuer, the software used was SPSS which is a modern system of data manipulation, statistical analysis and presentation graphics. In research, we identify the risk of each customer leave the product through a score.
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The frequency selective surfaces, or FSS (Frequency Selective Surfaces), are structures consisting of periodic arrays of conductive elements, called patches, which are usually very thin and they are printed on dielectric layers, or by openings perforated on very thin metallic surfaces, for applications in bands of microwave and millimeter waves. These structures are often used in aircraft, missiles, satellites, radomes, antennae reflector, high gain antennas and microwave ovens, for example. The use of these structures has as main objective filter frequency bands that can be broadcast or rejection, depending on the specificity of the required application. In turn, the modern communication systems such as GSM (Global System for Mobile Communications), RFID (Radio Frequency Identification), Bluetooth, Wi-Fi and WiMAX, whose services are highly demanded by society, have required the development of antennas having, as its main features, and low cost profile, and reduced dimensions and weight. In this context, the microstrip antenna is presented as an excellent choice for communications systems today, because (in addition to meeting the requirements mentioned intrinsically) planar structures are easy to manufacture and integration with other components in microwave circuits. Consequently, the analysis and synthesis of these devices mainly, due to the high possibility of shapes, size and frequency of its elements has been carried out by full-wave models, such as the finite element method, the method of moments and finite difference time domain. However, these methods require an accurate despite great computational effort. In this context, computational intelligence (CI) has been used successfully in the design and optimization of microwave planar structures, as an auxiliary tool and very appropriate, given the complexity of the geometry of the antennas and the FSS considered. The computational intelligence is inspired by natural phenomena such as learning, perception and decision, using techniques such as artificial neural networks, fuzzy logic, fractal geometry and evolutionary computation. This work makes a study of application of computational intelligence using meta-heuristics such as genetic algorithms and swarm intelligence optimization of antennas and frequency selective surfaces. Genetic algorithms are computational search methods based on the theory of natural selection proposed by Darwin and genetics used to solve complex problems, eg, problems where the search space grows with the size of the problem. The particle swarm optimization characteristics including the use of intelligence collectively being applied to optimization problems in many areas of research. The main objective of this work is the use of computational intelligence, the analysis and synthesis of antennas and FSS. We considered the structures of a microstrip planar monopole, ring type, and a cross-dipole FSS. We developed algorithms and optimization results obtained for optimized geometries of antennas and FSS considered. To validate results were designed, constructed and measured several prototypes. The measured results showed excellent agreement with the simulated. Moreover, the results obtained in this study were compared to those simulated using a commercial software has been also observed an excellent agreement. Specifically, the efficiency of techniques used were CI evidenced by simulated and measured, aiming at optimizing the bandwidth of an antenna for wideband operation or UWB (Ultra Wideband), using a genetic algorithm and optimizing the bandwidth, by specifying the length of the air gap between two frequency selective surfaces, using an optimization algorithm particle swarm
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Chronic venous disease (CVD) is evident among the chronic diseases and affects the elderly population and primarily is responsible for leg ulcers in this population. The use of dressings in the care of a venous ulcer is a fundamental part of the treatment for healing, however, evidence to assist in choosing the best dressing is scarce. The main objective of this study was to evaluate the effectiveness of treatment with hydrogel in the healing of venous ulcers using search methods, synthesis of information and statistical research through a systematic review and meta-analysis. Randomized controlled trials were selected in the following databases: CENTRAL; DARE; NHS EED; MEDLINE; EMBASE; CINAHL. Beyond these databases three websites were consulted to identify ongoing studies: ClinicalTrials.gov, OMS ICTRP e ISRCTN. The primary outcomes were analyzed: complete wound healing, incidence of wound infection and the secondary were: changes in ulcer size, time to ulcer healing, recurrence of ulcer, quality of life of participants, pain and costs of treatment. Four studies are currently included in the review with a total of 250 participants. The use of hydrogel appears to be superior to conventional dressing, gauze soaked in saline, for the healing of venous leg ulcers; 16/30 patients showed complete healing of ulcers (RR 5,33, 95%CI [1,73,16,42]). The alginate gel was shown to be more effective when compared to the hydrogel dressing in reduction of the wound area; 61,2% (± 26,2%) with alginate e 19,4% (± 24,3%) with hydrogel at the end of four weeks of treatment. Manuka honey has shown to be similar to the hydrogel dressings in percentage of area reduction. This review demonstrated that there is no evidence available about the effectiveness of the hydrogel compared to other types of dressings on the healing of venous leg ulcers of the lower limbs, thus demonstrating the need of future studies to assist health professionals in choosing the correct dressing.
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This paper proposes a new approach and coding scheme for solving economic dispatch problems (ED) in power systems through an effortless hybrid method (EHM). This novel coding scheme can effectively prevent futile searching and also prevents obtaining infeasible solutions through the application of stochastic search methods, consequently dramatically improves search efficiency and solution quality. The dominant constraint of an economic dispatch problem is power balance. The operational constraints, such as generation limitations, ramp rate limits, prohibited operating zones (POZ), network loss are considered for practical operation. Firstly, in the EHM procedure, the output of generator is obtained with a lambda iteration method and without considering POZ and later in a genetic based algorithm this constraint is satisfied. To demonstrate its efficiency, feasibility and fastness, the EHM algorithm was applied to solve constrained ED problems of power systems with 6 and 15 units. The simulation results obtained from the EHM were compared to those achieved from previous literature in terms of solution quality and computational efficiency. Results reveal that the superiority of this method in both aspects of financial and CPU time. (C) 2011 Elsevier Ltd. All rights reserved.
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Pós-graduação em Bases Gerais da Cirurgia - FMB
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Este trabalho constitui-se num estudo sobre o curso de formação de professores de Química da UFPA, contando sua história a partir dos desenhos curriculares que o nortearam nos seus 30 anos de existência e inserindo tal história no contexto maior da construção da ciência moderna. O estudo prossegue analisando, à luz da literatura, o projeto político-pedagógico recém aprovado pelo Colegiado do Curso visando detectar possíveis avanços e conclui respondendo, a partir do quadro delineado pela história do Curso e pelo momento presente, à questão: em função das demandas impostas pela sociedade moderna, como deve ser formado, hoje, um professor de química? Foram usados como principais métodos de pesquisa, coleta de depoimentos mediante entrevistas semi-estruturadas e pesquisa documental e bibliográfica, com maior ênfase a esta última.
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Este trabalho apresenta um método para encontrar um conjunto de pontos de operação, os quais são ótimos de Pareto com diversidade, para linhas digitais de assinante (DSL - digital subscriber line). Em diversos trabalhos encontrados na literatura, têm sido propostos algoritmos para otimização da transmissão de dados em linhas DSL, que fornecem como resultado apenas um ponto de operação para os modems. Esses trabalhos utilizam, em geral, algoritmos de balanceamento de espectro para resolver um problema de alocação de potência, o que difere da abordagem apresentada neste trabalho. O método proposto, chamado de diverseSB , utiliza um processo híbrido composto de um algoritmo evolucionário multiobjetivo (MOEA - multi-objective evolutionary algorithm), mais precisamente, um algoritmo genético com ordenamento por não-dominância (NSGA-II - Non-Dominated Sorting Genetic Algorithm II), e usando ainda, um algoritmo de balanceamento de espectro. Os resultados obtidos por simulações mostram que, para uma dada diversidade, o custo computacional para determinar os pontos de operação com diversidade usando o algoritmo diverseSB proposto é muito menor que métodos de busca de “força bruta”. No método proposto, o NSGA-II executa chamadas ao algoritmo de balanceamento de espectro adotado, por isso, diversos testes envolvendo o mesmo número de chamadas ao algoritmo foram realizadas com o método diverseSB proposto e o método de busca por força bruta, onde os resultados obtidos pelo método diverseSB proposto foram bem superiores do que os resultados do método de busca por força bruta. Por exemplo, o método de força bruta realizando 1600 chamadas ao algoritmo de balanceamento de espectro, obtém um conjunto de pontos de operação com diversidade semelhante ao do método diverseSB proposto com 535 chamadas.
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Purpose - The purpose of this paper is twofold: to analyze the computational complexity of the cogeneration design problem; to present an expert system to solve the proposed problem, comparing such an approach with the traditional searching methods available.Design/methodology/approach - The complexity of the cogeneration problem is analyzed through the transformation of the well-known knapsack problem. Both problems are formulated as decision problems and it is proven that the cogeneration problem is np-complete. Thus, several searching approaches, such as population heuristics and dynamic programming, could be used to solve the problem. Alternatively, a knowledge-based approach is proposed by presenting an expert system and its knowledge representation scheme.Findings - The expert system is executed considering two case-studies. First, a cogeneration plant should meet power, steam, chilled water and hot water demands. The expert system presented two different solutions based on high complexity thermodynamic cycles. In the second case-study the plant should meet just power and steam demands. The system presents three different solutions, and one of them was never considered before by our consultant expert.Originality/value - The expert system approach is not a "blind" method, i.e. it generates solutions based on actual engineering knowledge instead of the searching strategies from traditional methods. It means that the system is able to explain its choices, making available the design rationale for each solution. This is the main advantage of the expert system approach over the traditional search methods. On the other hand, the expert system quite likely does not provide an actual optimal solution. All it can provide is one or more acceptable solutions.
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Pós-graduação em Engenharia Mecânica - FEG
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Background: Pectus excavatum is characterized by a depression of the anterior chest wall (sternum and lower costal cartilages) and is the most frequently occurring chest wall deformity. The prevalence ranges from 6.28 to 12 cases per 1000 around the world. Generally pectus excavatum is present at birth or is identified after a few weeks or months; however, sometimes it becomes evident only at puberty. The consequence of the condition on a individual's life is variable, some live a normal life and others have physical and psychological symptoms such as: precordial pain after exercises; impairments of pulmonary and cardiac function; shyness and social isolation. For many years, sub-perichondrial resection of the costal cartilages, with or without transverse cuneiform osteotomy of the sternum and placement of a substernal support, called conventional surgery, was the most accepted option for surgical repair of these patients. From 1997 a new surgical repair called, minimally invasive surgery, became available. This less invasive surgical option consists of the retrosternal placement of a curved metal bar, without resections of the costal cartilages or sternum osteotomy, and is performed by videothoracoscopy. However, many aspects that relate to the benefits and harms of both techniques have not been defined. Objectives: To evaluate the effectiveness and safety of the conventional surgery compared with minimally invasive surgery for treating people with pectus excavatum. Search methods: With the aim of increasing the sensitivity of the search strategy we used only terms related to the individual's condition (pectus excavatum); terms related to the interventions, outcomes and types of studies were not included. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, LILACS, and ICTPR. Additionally we searched yet reference lists of articles and conference proceedings. All searches were done without language restriction. Date of the most recent searches: 14 January 2014. Selection criteria: We considered randomized or quasi-randomized controlled trials that compared traditional surgery with minimally invasive surgery for treating pectus excavatum. Data collection and analysis: Two review authors independently assessed the eligibility of the trials identified and agreed trial eligibility after a consensus meeting. The authors also assessed the risk of bias of the eligible trials. Main results: Initially we located 4111 trials from the electronic searches and two further trials from other resources. All trials were added into reference management software and the duplicates were excluded, leaving 2517 studies. The titles and abstracts of these 2517 studies were independently analyzed by two authors and finally eight trials were selected for full text analysis, after which they were all excluded, as they did not fulfil the inclusion criteria. Authors' conclusions: There is no evidence from randomized controlled trials to conclude what is the best surgical option to treat people with pectus excavatum.
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Pectus excavatum is characterized by a depression of the anterior chest wall (sternum and lower costal cartilages) and is the most frequently occurring chest wall deformity. The prevalence ranges from 6.28 to 12 cases per 1000 around the world. Generally pectus excavatum is present at birth or is identified after a few weeks or months; however, sometimes it becomes evident only at puberty. The consequence of the condition on a individual’s life is variable, some live a normal life and others have physical and psychological symptoms such as: precordial pain after exercises; impairments of pulmonary and cardiac function; shyness and social isolation. For many years, sub-perichondrial resection of the costal cartilages, with or without transverse cuneiform osteotomy of the sternum and placement of a substernal support, called conventional surgery, was the most accepted option for surgical repair of these patients. From 1997 a new surgical repair called, minimally invasive surgery, became available. This less invasive surgical option consists of the retrosternal placement of a curved metal bar, without resections of the costal cartilages or sternum osteotomy, and is performed by videothoracoscopy. However, many aspects that relate to the benefits and harms of both techniques have not been defined. Objectives To evaluate the effectiveness and safety of the conventional surgery compared with minimally invasive surgery for treating people with pectus excavatum. Search methods With the aim of increasing the sensitivity of the search strategy we used only terms related to the individual’s condition (pectus excavatum); terms related to the interventions, outcomes and types of studies were not included. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, LILACS, and ICTPR. Additionally we searched yet reference lists of articles and conference proceedings. All searches were done without language restriction.
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Context. Convergent point (CP) search methods are important tools for studying the kinematic properties of open clusters and young associations whose members share the same spatial motion. Aims. We present a new CP search strategy based on proper motion data. We test the new algorithm on synthetic data and compare it with previous versions of the CP search method. As an illustration and validation of the new method we also present an application to the Hyades open cluster and a comparison with independent results. Methods. The new algorithm rests on the idea of representing the stellar proper motions by great circles over the celestial sphere and visualizing their intersections as the CP of the moving group. The new strategy combines a maximum-likelihood analysis for simultaneously determining the CP and selecting the most likely group members and a minimization procedure that returns a refined CP position and its uncertainties. The method allows one to correct for internal motions within the group and takes into account that the stars in the group lie at different distances. Results. Based on Monte Carlo simulations, we find that the new CP search method in many cases returns a more precise solution than its previous versions. The new method is able to find and eliminate more field stars in the sample and is not biased towards distant stars. The CP solution for the Hyades open cluster is in excellent agreement with previous determinations.
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Radial velocities measured from near-infrared (NIR) spectra are a potential tool to search for extrasolar planets around cool stars. High resolution infrared spectrographs now available reach the high precision of visible instruments, with a constant improvement over time. GIANO is an infrared echelle spectrograph and it is a powerful tool to provide high resolution spectra for accurate radial velocity measurements of exo-planets and for chemical and dynamical studies of stellar or extragalactic objects. No other IR instruments have the GIANO's capability to cover the entire NIR wavelength range. In this work we develop an ensemble of IDL procedures to measure high precision radial velocities on a few GIANO spectra acquired during the commissioning run, using the telluric lines as wevelength reference. In Section 1.1 various exoplanet search methods are described. They exploit different properties of the planetary system. In Section 1.2 we describe the exoplanet population discovered trough the different methods. In Section 1.3 we explain motivations for NIR radial velocities and the challenges related the main issue that has limited the pursuit of high-precision NIR radial velocity, that is, the lack of a suitable calibration method. We briefly describe calibration methods in the visible and the solutions for IR calibration, for instance, the use of telluric lines. The latter has advantages and problems, described in detail. In this work we use telluric lines as wavelength reference. In Section 1.4 the Cross Correlation Function (CCF) method is described. This method is widely used to measure the radial velocities.In Section 1.5 we describe GIANO and its main science targets. In Chapter 2 observational data obtained with GIANO spectrograph are presented and the choice criteria are reported. In Chapter 3 we describe the detail of the analysis and examine in depth the flow chart reported in Section 3.1. In Chapter 4 we give the radial velocities measured with our IDL procedure for all available targets. We obtain an rms scatter in radial velocities of about 7 m/s. Finally, we conclude that GIANO can be used to measure radial velocities of late type stars with an accuracy close to or better than 10 m/s, using telluric lines as wevelength reference. In 2014 September GIANO is being operative at TNG for Science Verification and more observational data will allow to further refine this analysis.
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The aim of this dissertation is to analyze the language of evaluation in Italian, English and French sustainability reports in order to observe how firms build their corporate image and to investigate the kind of relationship they develop with their stakeholders. The analysis is carried out by applying Martin & White's Appraisal theory and corpus linguistics methods. For the purposes of this research, a multilingual specialized corpus of sustainability reports has been created, which is the result of two different levels of compilation. At the first level, three sub-corpora have been created with the aim of representing three different languages (Italian, English and French): at this level, the research on evaluative language will show that a standardization process of sustainability reports is underway. At the second level of compilation, each of the three sub-corpora has been split in two further sub-corpora, representative of two different business sectors: at this level, the research will show how the sector where firms operate directly influences the choice of the topics to be discussed. The first chapter of this dissertation introduces the concept of evaluative language, with a particular focus on the framework of Appraisal theory. The second chapter deals with corpus linguistics and describes different types of corpora, the search methods and the criteria for the compilation of corpora. The third chapter discusses the concepts of Corporate Social Responsibility and sustainability reports, focusing mainly on the reporting principles and the linguistic patterns of this genre, and provides an overview of the main guidelines and certifications for the reporting of sustainability actions. Chapter four is dedicated to the description of the methodology used for this research, while the last chapter presents and discusses the results of the analysis, in an attempt to draw generalizations on the use of evaluative language in this emerging genre.