Particle swarm optimisation assisted classification using elastic net prefiltering

A novel two-stage construction algorithm for linear-in-the-parameters classifier is proposed, aiming at noisy two-class classification problems. The purpose of the first stage is to produce a prefiltered signal that is used as the desired output for the second stage to construct a sparse linear-in-the-parameters classifier. For the first stage learning of generating the prefiltered signal, a two-level algorithm is introduced to maximise the model's generalisation capability, in which an elastic net model identification algorithm using singular value decomposition is employed at the lower level while the two regularisation parameters are selected by maximising the Bayesian evidence using a particle swarm optimization algorithm. Analysis is provided to demonstrate how “Occam's razor” is embodied in this approach. The second stage of sparse classifier construction is based on an orthogonal forward regression with the D-optimality algorithm. Extensive experimental results demonstrate that the proposed approach is effective and yields competitive results for noisy data sets.

Elastic net orthogonal forward regression

An efficient two-level model identification method aiming at maximising a model׳s generalisation capability is proposed for a large class of linear-in-the-parameters models from the observational data. A new elastic net orthogonal forward regression (ENOFR) algorithm is employed at the lower level to carry out simultaneous model selection and elastic net parameter estimation. The two regularisation parameters in the elastic net are optimised using a particle swarm optimisation (PSO) algorithm at the upper level by minimising the leave one out (LOO) mean square error (LOOMSE). There are two elements of original contributions. Firstly an elastic net cost function is defined and applied based on orthogonal decomposition, which facilitates the automatic model structure selection process with no need of using a predetermined error tolerance to terminate the forward selection process. Secondly it is shown that the LOOMSE based on the resultant ENOFR models can be analytically computed without actually splitting the data set, and the associate computation cost is small due to the ENOFR procedure. Consequently a fully automated procedure is achieved without resort to any other validation data set for iterative model evaluation. Illustrative examples are included to demonstrate the effectiveness of the new approaches.

A comparative study of the characteristics of French Fries produced by deep fat frying and air frying

Air frying is being projected as an alternative to deep fat frying for producing snacks such as French Fries. In air frying, the raw potato sections are essentially heated in hot air containing fine oil droplets, which dehydrates the potato and attempts to impart the characteristics of traditionally produced French fries, but with a substantially lower level of fat absorbed in the product. The aim of this research is to compare: 1) the process dynamics of air frying with conventional deep fat frying under otherwise similar operating conditions, and 2) the products formed by the two processes in terms of color, texture, microstructure, calorimetric properties and sensory characteristics Although, air frying produced products with a substantially lower fat content but with similar moisture contents and color characteristics, it required much longer processing times, typically 21 minutes in relation to 9 minutes in the case of deep fat frying. The slower evolution of temperature also resulted in lower rates of moisture loss and color development reactions. DSC studies revealed that the extent of starch gelatinization was also lower in the case of air fried product. In addition, the two types of frying also resulted in products having significantly different texture and sensory characteristics.

Environmental factors and features that influence visual search in a 3D WIMP interface

The challenge of moving past the classic Window Icons Menus Pointer (WIMP) interface, i.e. by turning it ‘3D’, has resulted in much research and development. To evaluate the impact of 3D on the ‘finding a target picture in a folder’ task, we built a 3D WIMP interface that allowed the systematic manipulation of visual depth, visual aides, semantic category distribution of targets versus non-targets; and the detailed measurement of lower-level stimuli features. Across two separate experiments, one large sample web-based experiment, to understand associations, and one controlled lab environment, using eye tracking to understand user focus, we investigated how visual depth, use of visual aides, use of semantic categories, and lower-level stimuli features (i.e. contrast, colour and luminance) impact how successfully participants are able to search for, and detect, the target image. Moreover in the lab-based experiment, we captured pupillometry measurements to allow consideration of the influence of increasing cognitive load as a result of either an increasing number of items on the screen, or due to the inclusion of visual depth. Our findings showed that increasing the visible layers of depth, and inclusion of converging lines, did not impact target detection times, errors, or failure rates. Low-level features, including colour, luminance, and number of edges, did correlate with differences in target detection times, errors, and failure rates. Our results also revealed that semantic sorting algorithms significantly decreased target detection times. Increased semantic contrasts between a target and its neighbours correlated with an increase in detection errors. Finally, pupillometric data did not provide evidence of any correlation between the number of visible layers of depth and pupil size, however, using structural equation modelling, we demonstrated that cognitive load does influence detection failure rates when there is luminance contrasts between the target and its surrounding neighbours. Results suggest that WIMP interaction designers should consider stimulus-driven factors, which were shown to influence the efficiency with which a target icon can be found in a 3D WIMP interface.

Microstructure and Mineral Composition of Dental Enamel of Permanent and Deciduous Teeth

Purpose: This study evaluated and compared in vitro the microstructure and mineral composition of permanent and deciduous teeth`s dental enamel. Methods: Sound third molars (n = 12) and second primary molars (n = 12) were selected and randomly assigned to the following groups, according to the analysis method performed (n = 4): Scanning electron microscopy (SEM), X-Ray diffraction (XRD) and Energy dispersive X-ray spectrometer (EDS). Qualitative and quantitative comparisons of the dental enamel were done. The microscopic findings were analyzed statistically by a nonparametric test (Kruskal-Wallis). The measurements of the prisms number and thickness were done in SEM photomicrographs. The relative amounts of calcium (Ca) and phosphorus (P) were determined by EDS investigation. Chemical phases present in both types of teeth were observed by the XRD analysis. Results: The mean thickness measurements observed in the deciduous teeth enamel was 1.14 mm and in the permanent teeth enamel was 2.58 mm. The mean rod head diameter in deciduous teeth was statistically similar to that of permanent teeth enamel, and a slightly decrease from the outer enamel surface to the region next to the enamel-dentine junction was assessed. The numerical density of enamel rods was higher in the deciduous teeth, mainly near EDJ, that showed statistically significant difference. The percentage of Ca and P was higher in the permanent teeth enamel. Conclusions: The primary enamel structure showed a lower level of Ca and P, thinner thickness and higher numerical density of rods. Microsc. Res. Tech. 73:572-577, 2010. (C) 2009 Wiley-Liss. Inc.

Effect of renoguanylin on hydrogen/bicarbonate ion transport in rat renal tubules

Renoguanylin (REN) is a recently described member of the guanylin family, which was first isolated from eels and is expressed in intestinal and specially kidney tissues. In the present work we evaluate the effects of REN on the mechanisms of hydrogen transport in rat renal tubules by the stationary microperfusion method. We evaluated the effect of 1 mu M and 10 mu M of renoguanylin (REN) on the reabsorption of bicarbonate in proximal and distal segments and found that there was a significant reduction in bicarbonate reabsorption. In proximal segments, REN promoted a significant effect at both 1 and 10 mu M concentrations. Comparing control and REN concentration of 1 mu M, JHCO(3)(-) . nmol cm(-2) s(-1) -1,76 +/- 0.11(control) x 1,29 +/- 0,08(REN) 10 mu m: P<0.05, was obtained. In distal segments the effect of both concentrations of REN was also effective, being significant e.g. at a concentration of 1 mu M (JHCO(3)(-), nmol cm(-2) s(-1) -0.80 +/- 0.07(control) x 0.60 +/- 0.06(REN) 1 mu m; P<0.05), although at a lower level than in the proximal tubule. Our results suggest that the action of REN on hydrogen transport involves the inhibition of Na(+)/H(+) exchanger and H(+)-ATPase in the luminal membrane of the perfused tubules by a PKG dependent pathway. (c) 2009 Elsevier B.V. All rights reserved.

Formal validation of automated policy refinement in the management of network security systems

Policy hierarchies and automated policy refinement are powerful approaches to simplify administration of security services in complex network environments. A crucial issue for the practical use of these approaches is to ensure the validity of the policy hierarchy, i.e. since the policy sets for the lower levels are automatically derived from the abstract policies (defined by the modeller), we must be sure that the derived policies uphold the high-level ones. This paper builds upon previous work on Model-based Management, particularly on the Diagram of Abstract Subsystems approach, and goes further to propose a formal validation approach for the policy hierarchies yielded by the automated policy refinement process. We establish general validation conditions for a multi-layered policy model, i.e. necessary and sufficient conditions that a policy hierarchy must satisfy so that the lower-level policy sets are valid refinements of the higher-level policies according to the criteria of consistency and completeness. Relying upon the validation conditions and upon axioms about the model representativeness, two theorems are proved to ensure compliance between the resulting system behaviour and the abstract policies that are modelled.

Cyclooxygenase-2 and vascular endothelial growth factor expression in 5-fluorouracil-induced oral mucositis in hamsters: evaluation of two low-intensity laser protocols

The aim of this study was to investigate the mechanisms whereby low-intensity laser therapy may affect the severity of oral mucositis. A hamster cheek pouch model of oral mucositis was used with all animals receiving intraperitoneal 5-fluorouracil followed by surface irritation. Animals were randomly allocated into three groups and treated with a 35 mW laser, 100 mW laser, or no laser. Clinical severity of mucositis was assessed at four time-points by a blinded examiner. Buccal pouch tissue was harvested from a subgroup of animals in each group at four time-points. This tissue was used for immunohistochemistry for cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF), and factor VIII (marker of microvessel density) and the resulting staining was quantified. Peak severity of mucositis was reduced in the 35 mW laser group as compared to the 100 mW laser and control groups. This reduced peak clinical severity of mucositis in the 35 mW laser group was accompanied by a significantly lower level of COX-2 staining. The 100 mW laser did not have an effect on the severity of clinical mucositis, but was associated with a decrease in VEGF levels at the later time-points, as compared to the other groups. There was no clear relationship of VEGF levels or microvessel density to clinical mucositis severity. The tissue response to laser therapy appears to vary by dose. Low-intensity laser therapy appears to reduce the severity of mucositis, at least in part, by reducing COX-2 levels and associated inhibition of the inflammatory response.

Diagnóstico das micro e pequenas empresas da cadeia produtiva moveleira da serra gaúcha : importância para o desenvolvimento setorial

The increasing of afluence demands the companies to be competitive and have a deep knowledge about the area wich they are participating. Through the search of management and produtive information, and the analisys of internal and external information, the company could identify strong and weak points , threats and oportunities, alowing the obtaince of competitive advantages. This research shows the result of a close search study about the usage of strategic planning and management technics, setting in evidence the necessity of micro and small furniture companies and furniture supply chain, represented in this case by sub-contract companies. Still looking to accentuate the importance that this study will represent to the setorial development, specially to the furniture companies wich have a big importance due to the report of small utilization of management technics in the sub-contract companies. Through analisys, it was possible to find out some common caracteristics in all 171 conmpanies evaluated, wich are showing likely 'sinalization', such as: - lower level os scholarship (96,5% elementary school, 3% until high school, 0,5% university/college graduration); - external market from Brazilian MPE¿s (5% export products to Mercosul and just 1% export products to Latin America, absenting exportations to other markets); - carefree with modern technics of management, certificates ISO 9000, 14000, MRP, CQT, among others; - carefree with strategic planning; - lower utilization of operacionl procedures, rules and function description; - ignoring the participating of market; - lower utilization of human resources index as a management form; - Small utilization of costs tabs (31%), with a small informatization level (8%) and apllying with non-management form; - low utilization of quality statistics (4%), re-working index (9%), among others. In syntesis, the basis expose that the great marjority of companies don¿t have knowledge about planning and the modern technics of management.

A stochastic discount factor approach to asset pricing using panel data asymptotics

Using the Pricing Equation in a panel-data framework, we construct a novel consistent estimator of the stochastic discount factor (SDF) which relies on the fact that its logarithm is the "common feature" in every asset return of the economy. Our estimator is a simple function of asset returns and does not depend on any parametric function representing preferences. The techniques discussed in this paper were applied to two relevant issues in macroeconomics and finance: the first asks what type of parametric preference-representation could be validated by asset-return data, and the second asks whether or not our SDF estimator can price returns in an out-of-sample forecasting exercise. In formal testing, we cannot reject standard preference specifications used in the macro/finance literature. Estimates of the relative risk-aversion coefficient are between 1 and 2, and statistically equal to unity. We also show that our SDF proxy can price reasonably well the returns of stocks with a higher capitalization level, whereas it shows some difficulty in pricing stocks with a lower level of capitalization.

Satisfação conjugal e aspectos relacionados: a influência da comunicação, da semelhança de atitudes e da percepção interpessoal

O objetivo desse estudo foi analisar a inter-relação entre Satisfação Conjugal e três aspectos considerados relevantes numa relação diádica: Comunicação, Percepção Interpessoal e Semelhança de Atitudes. Examinou-se, também, a influência de outras variáveis (idade, tempo de casado, auto-estima, renda, escolaridade e filhos) sobre Satisfação Conjugal. Pretendeu-se, além disso, verificar, em nosso ambiente cultural, a pertinência de alguns resultados obtidos pela Dr. Susan Singer Hendrick em estudo semelhante conduzido nos Estados Unidos. Através da análise histórica do casamento e dos fatores a ele associados foi proposto um modelo capaz de avaliar Satisfação Conjugal e a importância relativa de cada fenômeno a ela relacionado. Foi examinado, sucintamente, como Satisfação Conjugal pode ser considerada sob o enfoque de duas teorias: a da Troca e a da Equidade. Apresentou-se, na parte relativa ao referencial teórico, uma revisão dos estudos que buscaram comprovar o relacionamento de Satisfação Conjugal com cada uma das variáveis do estudo. No capítulo referente ao objeto do estudo, mais precisamente na formulação do problema, buscou-se mostrar a possível existência de uma relação integrada e conjunta entre as três variáveis e Satisfação Conjugal. Não se tem notícia de trabalho semelhante conduzido em nosso país, daí seu caráter pioneiro. A verificação da formulação teórica proposta efetuou-se através de uma pesquisa de campo, com base em dados de uma amostra de quarenta e oito casais de diversas idades, profissões, níveis de escolaridade, etc. e residentes no município do Rio de Janeiro. Os resultados alcançados apontaram Percepção Interpessoal e Auto-estima como as variáveis de maior importância relativa. Teve-se, também, a oportunidade de inferir que a mulher, talvez por força de condicionantes sócio-culturais, se coloca numa posição de inferioridade na relação conjugal.

"Não somos diferentes das outras pessoas": a vida cotidiana de mulheres com deficiência mental contada por elas mesmas

O objetivo desta pesquisa foi investigar a vida cotidiana de mulheres rotuladas como deficientes mentais, através de seus relatos biográficos pessoais. As entrevistadas descreveram sua rotina em casa e na instituição, falaram sobre suas famílias, relacionamentos, dificuldades em integração social, e sobre seus problemas físicos e de aprendizagem. Ficou clara no discurso deste grupo a dicotomia entre o mundo “de dentro", compreendendo os espaços protegidos da casa e da instituição, e o mundo ameaçador e violento “de fora", representado pela rua. Seus relacionamentos sociais restringem-se aos personagens do mundo “de dentro": a família, os profissionais, e os colegas da instituição, e muitas entrevistadas disseram se· sentir discriminadas pelas pessoas “de fora". Embora várias mulheres tenham exprimido o desejo de ser independentes (trabalhar fora, sair sozinhas, etc), na prática mantém urna relação de extrema dependência familiar. A pesar de dois terços das entrevistadas terem mais de 20 anos, elas não parecem ter nenhuma perspectiva concreta de morar sozinhas, casar, ou vir a formar sua própria família. Um dos pressupostos deste estudo era de que o estigma da deficiência mental, seria o terna central nas histórias de vida. Entretanto, mais da metade dos sujeitos não abordou esta questão, e muito poucas se autodenominaram deficientes. Foi postulado que os efeitos do estigma talvez sejam minimizados neste grupo devido à superproteção familiar e institucional por um lado, e a evitação do mundo "de fora" (onde esta condição seria denunciada mais abertamente) por outro. Assim sendo, em sua prática diária, a maioria dessas mulheres têm poucas oportunidades de se confrontar com a situação de marginalização. Deficiência mental foi analisada como um fenômeno socialmente construído, e acredita-se que estas pessoas funcionem em um nível mais dependente do que sua condição orgânica exigiria, por terem sido reforçadas por representar o papel social de deficientes. Apesar das características comuns, cada história de vida provou ser original e única, mostrando o erro em se considerar as pessoas portadoras de deficiência mental como um grupo homogêneo e bem definido. Além disso, a não ser pela dependência familiar, falta de participação autônoma e integrada na comunidade, e relacionamento amoroso e sexual restrito, a ideia dessas mulheres não é qualitativamente diferente do resto da população.

Empréstimo de ações no Brasil

Este trabalho investiga a atividade de empréstimo de ações no Brasil e sua conexão com operações de venda a descoberto em bolsa de valores. Descreve a organização do mercado, identifica fatores que determinam o nível de empréstimos e analisa os efeitos na eficiência da formação de preços das ações. Conclui que os vendedores atuam como contrários e que a atividade tem relação direta com o volume de negociação e inversa com a amplitude diária dos preços. Períodos de lock up e estabilização, esses após os IPOs, e o que antecede às ofertas subsequentes também influenciam o saldo de empréstimos, assim como a arbitragem tributária na distribuição, pelas empresas, de juros sobre capital próprio que tem efeito disruptivo sobre os preços das ações. Investidores a descoberto posicionam-se de modo a auferir excesso de retornos negativos e preferem ações com betas mais elevados. Os resultados também demonstram que o acréscimo de posições long-short a portfólio de investimento já existente aumentaria o retorno e reduziria o risco de mercado. Sobre a eficiência do mercado brasileiro, o estudo mostra que os preços das ações com saldos elevados de empréstimos ajustam-se com mais rapidez aos movimentos do mercado do que aquelas com menor saldo. O trabalho contribui, ainda, com recomendações pontuais para alterações da regulação e da organização operacional da atividade no País.

Performance-based compensation vs. guaranteed compensation: contractual incentives and performance

Top management from retail banks must delegate authority to lower-level managers to operate branches and service centers. Doing so, they must navigate through conflicts of interest, asymmetric information and limited monitoring in designing compensation plans for such agents. Pursuant to this delegation, the banks adopt a system of performance targets and incentives to align the interests of senior management and unit managers. This paper evaluates the causal relationship between performance-based salaries and managers’ effective performance. We use a fixed effects estimator to analyze an unbalanced panel of data from one of the largest Brazilian retail banks during the period from January 2007 to June 2009. The results indicate that agents with guaranteed variable salary contracts demonstrate inferior performance compared with agents who have performance-based compensation packages. We conclude that there is a moral hazard that can be observed in the behavior of agents who are subject to guaranteed variable salary contracts.

A interatividade na aprendizagem: uma perspectiva cognitiva utilizando conteúdo multimídia

A migração de materiais educacionais para dispositivos portáteis, tais como computadores do tipo tablet, torna possível oferecer altos níveis de interatividade na apresentação de animações e, dessa forma, pesquisas são necessárias para avaliar o valor pedagógico de incorporar recursos sofisticados de interatividade em lições para dispositivos portáteis. Estudantes de Engenharia (no Experimento 1) e estudantes de nível superior de outras áreas (no Experimento 2) estudaram por 5 minutos uma animação mostrando, em um computador do tipo tablet, os seis passos de um procedimento de manutenção para um dispositivo mecânico chamado Tomada de Força. A animação envolveu um baixo nível de interatividade, no qual os estudantes eram capazes de reproduzir, pausar, avançar e voltar a animação por meio de botões acionados em tela sensível ao toque (touch screen); um alto nível de interatividade, no qual os estudantes podiam também tocar e deslizar um dedo na tela para rotacionar a animação ou ainda tocar a tela com dois dedos abrindo-os ou fechando-os para ampliar ou reduzir a animação; ou nenhuma interatividade (apenas no Experimento 2). De forma geral, em ambos os experimentos, os estudantes que utilizaram alto nível de interatividade reportaram maior interesse, mas não mostraram melhor aprendizagem, comparados aos grupos de baixa ou nenhuma interatividade. Entretanto, no Experimento 2, estudantes que se classificaram como alunos verbais demonstraram maior interesse e obtiveram pontuações mais altas de aprendizagem com alta interatividade, em vez de baixa ou nenhuma interatividade. Esse padrão, contudo, não foi encontrado entre os alunos visuais. Também no Experimento 2, os alunos verbais e os alunos com baixo nível de autorregulação de aprendizagem, que manifestaram alto nível de interesse, obtiveram pontuações mais altas de aprendizagem do que os alunos visuais e os alunos com alto nível de autorregulação de aprendizagem, que manifestaram baixo nível de interesse, respectivamente.