bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanocompósitos de Poli(Cloreto de Vinila) (PVC)/argilas organofílicas
Authors: Souza Michelle A. , Pessan Luiz A. , Rodolfo Jr. Antonio
Published: April 2007

O interesse pelo desenvolvimento de nanocompósitos com matrizes poliméricas aumentou significativamente nos últimos anos, levando a uma grande quantidade de trabalhos publicados e de grupos de pesquisa e desenvolvimento interessados e trabalhando nesta importante área. Em geral, os materiais inorgânicos não apresentam uma boa interação com polímeros orgânicos, o que é desejável para obter um bom estado de dispersão no sistema e otimização de desempenho. Em função desta característica dos sistemas polímeros orgânicos/materiais inorgânicos como argila, tem-se buscado uma solução para este problema através de tratamentos prévios de superfícies das argilas com modificadores orgânicos. Os nanocompósitos poliméricos utilizando argila usualmente apresentam propriedades mecânicas e térmicas bastante atrativas e superiores aos compósitos convencionais, bem como valores reduzidos de permeabilidade, melhor resistência química a solventes e maior retardância a chama. Nas últimas décadas, nanocompósitos de policloreto de vinila (PVC) também têm sido preparados através de intercalação no estado fundido e apresentam resultados interessantes mas ainda com possibilidades de melhoria em função do potencial do material e de estudos similares com outras matrizes termoplásticas. O PVC é um material muito mais versátil e devido à sua necessidade de formulação mediante a incorporação de aditivos, o PVC pode ter suas características alteradas dentro de um amplo espectro de propriedades em função da aplicação final e características finais desejadas. Entretanto, devido a suas desvantagens inerentes, tais como baixa resistência à fratura, baixa estabilidade térmica e produção de fumaça escura durante sua combustão, o PVC e seus compósitos estão sujeitos a algumas limitações em certas aplicações. Dessa forma, o desenvolvimento de nanocompósitos poliméricos é uma alternativa promissora para tentar superar essas limitações e possibilitar o desenvolvimento de novos produtos com desempenho e propriedades diferenciados.
Copolimerização em emulsão de acetato de vinila e acrilato de butila com alto teor de sólidos
Authors: Palma Mauri , Giudici Reinaldo
Published: April 2007

Neste trabalho foi investigada a influência da concentração de uma mistura dos emulsificantes nonilfenol etoxilado e sulfato sódico de nonilfenol etoxilado (não iônico e iônico, respectivamente) e concentração de protetor coloidal, poli (álcool vinílico) na estabilidade coloidal de látices do copolímero acetato de vinila (AV)/acrilato de butila (AB) com alto teor de sólidos. Foram determinados o teor de sólidos e o tamanho médio das partículas ao longo da reação e foram obtidas as viscosidades das emulsões finais. Os ensaios foram realizados de acordo com um projeto fatorial com 3 níveis de concentração de emulsificantes e de protetor coloidal. Foi verificado que são necessárias maiores quantidades relativas de emulsificantes e de protetor coloidal pela massa total de monômeros para se obter látices estáveis com teores de sólidos de 70 e 73% (m/m). Os tamanhos médios das partículas no final de cada ensaio foram relativamente elevados (800 a 1000 nm) e as viscosidades a 20°C relativamente baixas (500 mPa.s) para teor de sólidos de 67% (m/m); para teor de sólidos de 70% (m/m) as viscosidades variaram de 5.000 a 10.000 mPa.s e para teor de sólidos de 73% (m/m) a viscosidade foi de 365.000 mPa.s.
Determinação da constante cinética de cristalização não-isotérmica de polipropilenos modificados com ácido acrílico e anidrido maleico
Authors: Carvalho Benjamim de M. , Bretas Rosario E. S.
Published: April 2007

O propósito do presente trabalho foi testar a validade do Método da Curva Mestre para a determinação da constante de cristalização não-isotérmica de polipropilenos modificados com anidrido maleico e ácido acrílico. Experimentos de cristalização não-isotérmica foram realizados a diversas taxas de resfriamento por meio de Calorimetria Exploratória Diferencial (DSC). Para serem usadas no Método da Curva Mestre, as curvas originais obtidas em DSC foram corrigidas em termos da defasagem de temperatura entre a amostra polimérica e o forno do equipamento. A equação de Nakamura e a constante de cristalização determinada foram utilizadas para simular as curvas de cristalinidade relativa em função da temperatura para as diversas taxas de resfriamento. As curvas simuladas apresentaram boa concordância com as curvas experimentais para ambas as amostras de polipropileno modificado, mostrando que o Método da Curva Mestre pode ser empregado com sucesso para este polímero.
Auto-avaliação de centros de pós-graduação: uma proposta em ação
Authors: Rocha Nívea Maria Fraga
Published: April 2007

A pesquisa Auto-Avaliação de Centros de Pós-Graduação, surgiu como instrumento de qualidade da Fundação Visconde de Cairu (FVC). Os objetivos visavam a elaborar proposta de Auto-Avaliação para o Centro de Pós-Graduação da Fundação Visconde de Cairu (CEPPEV/FVC), que atendesse às exigências do contexto, características da FVC e possibilitasse a participação da comunidade acadêmica. A metodologia de pesquisa utilizada foi a pesquisa-ação, através de oficinas. Esse processo possibilitou construir coletivamente o diagnóstico institucional, identificar forças que facilitam e dificultam o processo educacional, demonstrar a qualidade do que se produz e utilizar os resultados no planejamento e tomada de decisões, para corrigir rumos e alcançar excelência institucional. A Auto-Avaliação do CEPPEV/FVC, sustentada por princípios democráticos, consolida sua responsabilidade social e compromisso científico-cultural.
Exotismo e autenticidade: relatos de viajantes à procura de sexo
Authors: Piscitelli Adriana
Published: April 2007

A produção sócio-antropológica que trata do turismo discute a oposição entre o caráter de massa atribuído ao olhar dos turistas contemporâneos e o caráter individual vinculado à "viagem". Este texto dialoga com argumentos presentes nessa oposição, a partir da análise etnográfica de relatos de viajantes à procura de sexo que freqüentam pontos do circuito internacional de turismo sexual. Centrando-se em narrativas ficcionais/experienciais, Plateforme, romance de Michel Houellebecq, recentemente publicado, os relatos de viagem de Mattioli Ross e histórias contadas por viajantes à procura de sexo, no marco de uma pesquisa sobre turismo sexual internacional no Nordeste do Brasil, o texto estabelece esse diálogo considerando as noções centrais presentes nesse conjunto de relatos atravessados por gênero: exotismo, sexualidade e autenticidade.
A construção do saber em Odontologia: a produção científica de três periódicos brasileiros de 1990 a 2004
Authors: Amorim Karla Patrícia Cardoso , Alves Maria do Socorro Costa Feitosa , Germano Raimunda Medeiros , Costa Iris do Céu Clara
Published: April 2007

Este estudo focaliza uma análise das temáticas abordadas por três revistas odontológicas brasileiras, durante o período de 1990 a 2004. Partimos do pressuposto de que estas têm um papel importante na formação profissional, pois são meios dinâmicos de divulgação do saber e, desta forma, podem influenciar e nortear pensamentos, reflexões e atitudes, moldando o fazer odontológico. A análise quantitativa do material empírico, totalizando 2.806 artigos estudados, revela a diversidade de temáticas e assuntos das publicações. As cinco temáticas mais abordadas referem-se às disciplinas técnicas e profissionalizantes, atingindo 52,73% dos trabalhos analisados. Esperamos contribuir para a compreensão do processo de produção de conhecimento, subsidiando reflexões e estudos posteriores e funcionando como parâmetro para o acompanhamento do pensar odontológico.
Programas de pós-graduação em Saúde Pública na Argentina e no Brasil: origens históricas e tendências recentes de processos de avaliação de qualidade
Authors: Hortale Virginia Alonso , Koifman Lilian
Published: April 2007

O artigo analisa a singularidade de metodologias utilizadas em processos de avaliação da qualidade da formação pós-graduada em Saúde Pública em dois países da América Latina Argentina e Brasil. Procedeu-se a uma busca em sítios da internet que abordavam os temas "formação em saúde pública" e "metodologias de avaliação de qualidade", além da revisão de documentos e bibliografia sobre o tema. A análise considerou as seguintes dimensões: o contexto político-econômico na América Latina nos últimos dez anos (1994-2004), as reformas nos sistemas educacionais (com ênfase na área da pós-graduação) e as metodologias de avaliação de qualidade implementadas. Foram identificadas semelhanças entre os sistemas de avaliação em vigor em ambos os países, assim como debilidades nesses processos: avaliação associada a supervisão e controle, e não a redirecionamento e reorientação do ensino, e obrigatoriedade dos cursos ajustarem-se a um modelo padrão definido pelos especialistas.
Cooperativismo agropecuário: os desafios do financiamento das necessidades líquidas de capital de giro
Authors: Gimenes Régio Márcio Toesca , Gimenes Fátima Maria Pegorini
Published: April 2007

O cooperativismo possui grande relevância para a economia brasileira, na medida em que atua apoiando o desenvolvimento econômico e social, principalmente das pequenas propriedades rurais. As cooperativas agropecuárias atuam no fomento e na comercialização dos produtos agrícolas, inclusive implantando novos cultivos e agregando valor aos produtos por meio de complexos agroindustriais. O crescimento dessas organizações, sobretudo pela verticalização de suas operações, tem exigido a busca de fontes de capital para financiar as necessidades líquidas de capital de giro dos seus negócios. Decisões sobre financiamento afetam diretamente a saúde financeira das organizações, à medida que produzem um risco financeiro maior. Portanto é relevante uma investigação sobre as fontes de financiamento das necessidades líquidas de capital de giro para as cooperativas agropecuárias, sendo este o objetivo primordial do artigo.
Redes e alianças estratégicas no Brasil: caso CVRD
Authors: Tauhata Tatiana L. , Macedo-Soares T. Diana L. V. A. de
Published: April 2007

No cenário atual de competição, as empresas têm estabelecido um número crescente de alianças e redes para complementar seus recursos, reduzir incertezas e sustentar sua vantagem competitiva. Este artigo pretende evidenciar a importância de levar em conta na gestão estratégica de empresas que atuam em redes de alianças as implicações destas redes para sua conduta e desempenho. Tem foco na maior exportadora brasileira que é líder mundial da indústria de minério de ferro - a Cia Vale do Rio Doce - usando uma metodologia de estudo de caso e um novo ferramental de análise estratégica sob a perspectiva relacional. Com base em pesquisa bibliográfica, documental e de campo, mostra que esta perspectiva pode trazer novos subsídios valiosos para o planejamento estratégico da empresa, ao revelar implicações, em termos de oportunidades, ameaças, forças e fraquezas das características das suas redes, que atenuam, neutralizam ou exacerbam àquelas identificadas por análises estratégicas tradicionais.
Soft Systems Methodology: uma aplicação no "pão dos pobres" de Porto Alegre
Authors: Bellini Carlo Gabriel Porto , Rech Ionara , Borenstein Denis
Published: April 2007

O artigo apresenta uma aplicação da Soft Systems Methodology (SSM) na entidade filantrópica porto-alegrense Pão dos Pobres de Santo Antônio, que presta assistência a meninos carentes. Busca-se divulgar no contexto nacional a SSM como metodologia para o tratamento de problemas complexos, bem como incentivar a interação de acadêmicos e empresários com setores comunitários especialmente necessitados. A aplicação da SSM resultou positiva para a entidade e para os pesquisadores: permitiu se estabelecer uma visão global e sistêmica da realidade do Pão dos Pobres, sugeriu alternativas para o enfrentamento de situações problemáticas nela identificadas, serviu de meio para os autores conhecerem aspectos da vida comunitária e promoveu cooperação e aprendizagem entre as pessoas envolvidas no estudo - um dos benefícios mais documentados na literatura como resultantes da aplicação da metodologia.
Gestão do conhecimento e das competências gerenciais: um estudo de caso na indústria automobilística
Authors: Vieira Adriane , Garcia Fernando Coutinho
Published: April 2007

O presente artigo trata das mudanças no sistema de gestão de pessoas, em organizações guiadas pela gestão do conhecimento e competências. Seu objetivo é descrever e analisar as novas formas e conteúdos dos processos de seleção e formação dos trabalhadores, colocadas em curso numa organização do setor automotivo que investe no desenvolvimento das habilidades e conhecimentos dos trabalhadores, a fim de mantê-los articulados com as mais recentes inovações microeletrônicas. Foram realizadas 26 entrevistas nas áreas de fabricação de motores, manutenção, regulagem de ferramentas e desenvolvimento organizacional. Os resultados mostram a gestão do conhecimento e das competências articuladas, as formas estratégicas de selecionar os trabalhadores mais flexíveis, prever sua capacidade de adaptação e desenvolver a formação de mão-de-obra fora do padrão-massa. Assim, investe-se naqueles que verdadeiramente interessam ao processo, a fim de reduzir custos operacionais, ao mesmo tempo em que são desenvolvidos sistemas motivacionais capazes de gerar envolvimento, integração e comprometimento.
Aprendizagem gerencial: teoria e prática
Authors: Moraes Liege Viviane dos Santos de , Silva Maria Aparecida da , Cunha Cristiano J. C. A.
Published: April 2007

A literatura indica um crescente interesse por uma área emergente de pesquisa e prática no campo das organizações: a aprendizagem gerencial. Tal área está preocupada com a investigação dos processos de aprendizagem que contribuem para a prática da gestão, o que inclui, embora não exclusivamente, a educação e o desenvolvimento gerencial. Tendo em vista que, no Brasil, esta área de pesquisa é ainda incipiente, o propósito deste artigo é apresentar uma revisão da literatura que consolida a aprendizagem gerencial como uma área emergente de pesquisa e prática no campo das organizações.
Paradoxos culturais na gestão de pessoas: cultura e contexto em uma cooperativa agro-industrial
Authors: Vasconcelos Isabella , Mascarenhas André Ofenhejim , Protil Roberto M.
Published: April 2007

O tema paradoxos organizacionais vem ganhando espaço no estudo das organizações. Em uma perspectiva dialética de evolução social, este conceito refere-se à realidade socialmente construída pelos atores, que representam os sistemas complexos nos quais estão inseridos em torno de duas percepções contraditórias que passam a orientar a sua ação. A partir das premissas do interacionismo simbólico, conceituamos e discutimos neste artigo um paradoxo cultural na gestão de pessoas por meio de um estudo etnográfico em uma cooperativa agro-industrial. Partimos da visão da organização como um complexo contexto cultural, formado pelo agrupamento de diversos sistemas de significação. Neste contexto, analisamos os conflitos gerados por interpretações divergentes de práticas sociais, resultado de repertórios culturais distintos, que causaram percepções contraditórias do sistema social. Discutimos estes conflitos em termos de sua influência na evolução do sistema organizacional. Ao final do artigo, fazemos algumas considerações acerca dos estudos futuros sobre o tema.
Induction of phenolics and defense-related enzymes in coconut (Cocos nucifera L.) roots treated with biocontrol agents
Authors: Karthikeyan M. , Radhika K. , Mathiyazhagan S. , Bhaskaran R. , Samiyappan R. , Velazhahan R.
Published: April 2007

The effect of soil application of biocontrol agents (Pseudomonas fluorescens, Trichoderma viride and T. harzianum) in combination with chitin on induction of phenolics and defense enzymes in coconut roots infected with Ganoderma lucidum, the causal agent of Ganoderma disease, was investigated. Soil application of these biocontrol formulations in combination with chitin induced a significant increase in the activities of peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL), chitinase and beta-1,3-glucanase in the G. lucidum infected palms. Activities of both PAL and PO reached maximum levels within 3 d while the activity of PPO reached the maximum level 6 d after application of a mixture of P. fluorescens, T. viride and chitin. Isozyme analysis revealed that unique PO3 and PPO2 isozymes were induced in coconut palms treated with P. fluorescens + T. viride + chitin. Accumulation of phenolics was recorded 3 d after treatment and reached maximum levels 9 d after treatment application. Activity of chitinase was significantly increased from the third day after treatment imposition and continued to increase up to 9 to 12 d in all treatments. Chitinase isozyme analysis revealed that a unique Chit3 isoform was induced in coconut roots treated with P. fluorescens + T. viride + chitin. The beta-1,3-glucanase activity was maximum 9 d after treatment application. The mechanisms by which P. fluorescens + T. viride + chitin reduced the incidence of Ganoderma disease in coconut may be related to its ability to induce defense mechanisms in coconut palms.
Foliar phosphorus supply and CO2 assimilation in common bean (Phaseolus vulgaris L.) under water deficit
Authors: Santos Mauro G. dos , Ribeiro Rafael V. , Teixeira Marcelo G. , Oliveira Ricardo F. de , Pimentel Carlos
Published: April 2007

Two common bean cultivars were grown in pots under greenhouse conditions. Plants were submitted to a foliar Pi spray two days before suspending irrigation, what enhanced net CO2 assimilation rate of Ouro Negro cultivar but did not change significantly the photosynthesis of Carioca cultivar under both water deficit and rehydration periods. The results revealed that a foliar Pi spray induced an up-regulation of photosynthesis in common bean under mild water deficit, with this effect being genotype-dependent.
Quilotórax espontâneo associado a atividade física leve
Authors: Torrejais José Carlos Miranda , Rau Carolina Borges , Barros João Adriano de , Torrejais Márcia Miranda
Published: April 2007

O quilotórax ocorre quando há ruptura, laceração ou obstrução do ducto torácico, com liberação de quilo no espaço pleural. Pode acontecer em malformações linfáticas congênitas, linfomas, tumores de mediastino, doenças infecciosas, procedimentos cirúrgicos, traumas automobilísticos, ou ser idiopático. Apresenta sinais clínicos de dispnéia, hipotensão, edema generalizado e cianose. O diagnóstico geralmente é feito por toracocentese e o tratamento é conservador. O quilotórax espontâneo é uma condição incomum de derrame pleural, e somente é hipótese diagnóstica após a exclusão das demais causas. Descrevemos um caso de quilotórax espontâneo associado a atividade física leve em academia de ginástica.
Fluxes of As, Cu, Hg, Pb in lake sediments in the Coppermine River basin, Canada
Authors: Peramaki Liisa , Stone Michael
Published: April 2007

Many watersheds in northern Canada are experiencing increasing pressures from resource extraction, development and the long-range transport of atmospheric pollutants. This study examines sediment accumulation and the spatial and temporal distribution of trace metals in bottom sediment of down gradient lakes in the headwaters of the Coppermine River basin, Canada. Sediment cores were collected from Lac de Gras, Desteffany Lake, Point Lake and Daring Lake using a plastic lined K–B single-gravity corer. Each core was dated using 210Pb and concentrations of trace metals (As, Cu, Hg, Pb) were determined in core sections. Sedimentation rates ranged from 101 g m−2 yr−1 at Desteffany Lake to 156 g m−2 yr−1 at Daring Lake and are comparable to other northern lakes. Concentrations of As and Cu were significantly higher at Lac de Gras. Metal loading data and enrichment ratios show that concentrations of Pb and Hg are elevated compared to historic background levels. Metal enrichment is from anthropogenic activities and atmospheric inputs. Lake sediment represents a good indicator of state for the Coppermine basin and documents historic trends of metal deposition. However, the indicator has low sensitivity to change and coarse temporal resolution due to low sedimentation rates in northern environments.
Using molecular tools to assess biofilms in onsite systems
Authors: Flapper T.G. , McKay A. , Hall S. , Hill P.
Published: April 2007

Onsite sewage treatment is growing in diversity, and in regulatory control across Australia. This is occurring for both blackwater and greywater treatment, as the drought impact deepens and more of the community are exposed to options for ‘managing’ their own water. Regulators in each State are drafting and implementing Guidelines to cover a range of on-site system scenarios. In addition, more and more decentralised options are being tendered for sewage management in the commercial world. In this project we aim to use novel molecular tools, in combination with traditional physical/chemical/biological methods, to understand onsite treatment in a more detailed manner. The system tested is a new peat based biofilter which can be used for greywater or blackwater application, and can be retrofitted to current sewage systems. This project has been based on the AquaReuse greywater system for demonstration purposes, showing the strength of the information gained from the use of novel tools. The two systems investigated are installed at a caravan park in New South Wales (NSW) and a domestic residence in Tamborine, Queensland (QLD). A 20-week intensive sampling and analysis program was followed. The project monitored standard analytes such as biochemical oxygen demand (BOD5), suspended solids (SS) and thermotolerant coliforms (TC). Additionally, we studied the biological community using fluorescent in situ hybridisation (FISH) on a monthly basis and full-cycle ribosomal RNA analysis (rRNA) for one sample to assess the biological community inhabitants. rRNA analysis at the NSW facility demonstrated a highly diverse biological community, in keeping with its long established operating period. In contrast, FISH analysis at the QLD installation showed a less diverse and younger community. rRNA and FISH identified organisms that are mostly associated with nutrient removing functions.
Use of real-time PCR to examine the relationship between ammonia oxidizing bacterial populations and nitrogen removal efficiency in a small decentralized treatment system ‘Johkasou’
Authors: Nakagawa G. , Ebie Y. , Tsuneda S. , Matsumura M. , Inamori Y.
Published: April 2007

The aim of this study was to examine the relationship between ammonia oxidizing bacterial populations and biological nitrogen removal in a small on-site domestic wastewater treatment system “Johkasou”. The population dynamics of ammonia oxidizing bacteria (AOB) in six full-scale advanced Johkasous was surveyed using real-time PCR assay over a period of one year. These Johkasous were selected to compare the AOB populations in different treatment performance. When the effluent NH4-N concentration was higher than 2 mg L−1, it was difficult to meet the effluent standard of advanced Johkasous (T-N 10 mg L−1). In contrast, the nitrogen removal efficiency was hardly affected by nitrite oxidation and denitrification in these systems. In other words, ammonia oxidation was a rate-limiting step. Furthermore, we focused on the relationship between NH4-N loading per AOB cell and nitrogen removal. Real time PCR monitoring results demonstrated that it is important to regulate NH4-N loading per AOB cell below 210 pg cell−1 day−1 to meet the effluent standard of advanced Johkasou. It is considered that NH4-N loading per AOB cell is a useful parameter for determining suitable nitrogen loading and small decentralized system design.
Treatment of organic synthesis wastewater using anaerobic packed bed and aerobic suspended growth bioreactors
Authors: Mijaylova-Nacheva P. , Ramírez-Camperos E. , Cuevas-Velasco S.
Published: April 2007

The performance of an anaerobic mesophilic packed bed reactor, with a mixture of GAC and tezontle, followed by an aerobic suspended growth system was studied for the treatment of organic chemical wastewater with a high COD concentration (22–29 g/L). The testing of the anaerobic–aerobic system was conducted in an experimental set-up for almost 2.5 years. Different operational conditions were evaluated. The anaerobic reactor showed performance stability and COD removals higher than 80% were obtained with loads up to 16.6 kg.m−3.d−1. The acclimation of the aerobic biomass to the substrate in the anaerobic effluent was very quick and COD removals higher than 94% were obtained even at high organic loads. The combined anaerobic–aerobic system allowed total COD removals higher than 99.5% and the accomplishment of the discharge requirements of 200 mgCOD/L when the anaerobic reactor was operated with loads of 8–11 kg.m−3.d−1 and the aerobic reactor with 0.33 kg.kg−1.d−1, being the total HRT of 4.4. The average TKN removal in the anaerobic–aerobic system was 97%, the average for the anaerobic reactor being 52% and that one for the aerobic system being 94%.
Spectral study on the molecular orientation of a tetracationic porphyrin dye on the surface of layered silicates
Authors: Čeklovský Alexander , Bujdák Juraj , Czímerová Adriana , Iyi Nobuo
Published: April 2007

Tetracationic porphyrin dyes TMPyP and ZnPyP were intercalated into hydrophobized layered silicate films of three smectites. The smectites represented the layered silicate specimens of high (Fluorohectorite, Corning; FHT), medium (Kunipia F montmorillonite; KF) and low layer charge (Laponite, Laporte; LAP). The molecular orientations of the dye cations were studied by means of linearly-polarized ultraviolet-visible (UV-VIS) spectroscopy. The spectral analysis and consequent calculations of tilting angles of the transition moments at the wavelengths of Soret band transitions were in the range of 25°-35°. The determined angles indicated molecular orientation of the dye cations being almost parallel to the surface of the silicates. Slightly higher values (above 35°), determined for a FHT film, indicated either a slightly tilted orientation of the dye cations or the change of molecular comformation after the intercalation of the dye.
Optoelectronic multiplexer for digital data processing based on lipid crystal pixels and optical fiber elements
Authors: Pérez I. , Pena J. , Torres J. , Manzanares R. , Marcos C. , Vázquez C.
Published: April 2007

In this work, we present an optoelectronic digital multiplexer 4:1 based on a multipixel nematic liquid crystal cell. This device uses two optical control signals to select one among four possible optical data inputs. These data signals are generated by four red LEDs, which are guided through plastic optical fiber towards liquid crystal pixels. For our purpose, only four pixels of the cell will be used to modulate the optical signal across them. Each pixel will be addressed by a square waveform coming from the conditioning circuit managed by a microcontroller system. The electronic control allows the multiplexer to work as as simple two input logical gates such as AND, NAND, OR, NOR, XOR and XNOR. The operation time of the device is limited by the response time of LC cell that is in the millisecond range.
Evaluation of infrared collimators for testing thermal imaging systems
Authors: Chrzanowski K.
Published: April 2007

Infrared reflective collimators are important components of expensive sophisticated test systems used for testing thermal imagers. Too low quality collimators can become a source of significant measurement errors and collimators of too high quality can unnecessarily increase cost of a test system. In such a situation it is important for test system users to know proper requirements on the collimator and to be able to verify its performance. A method for evaluation of infrared reflective collimators used in test systems for testing thermal imagers is presented in this paper. The method requires only easily available optical equipment and can be used not only by collimator manufactures but also by users of test equipment to verify performance of the collimators used for testing thermal imagers.
A new multi-path scheme for adaptive computation-aware motion estimation
Authors: Jakubowski M. , Pastuszak G.
Published: April 2007

Ability to work in a computation-limited and computation-variant environment described as “computational awareness” is a desirable feature of a real-time motion estimation system. In this paper, a new multi-path computation-aware algorithm is proposed. One-pass scheme, presented in the prior work by Chen et al., considers only one candidate point which is the median of neighbouring motion vectors (MVs). However, when computational resources are abundant, it is possible to investigate more search paths around points from the prediction set and get a significant improvement both in terms of quality and utilization of available search points (SPs). There are also other enhancements introduced regarding the way of selection of the starting SP and the search strategy, and allocation of resources, which leads to higher PSNR and a better utilization of computational resources.
Computation of Realizations Composed of Dynamic and Static Parts of Improper Transfer Matrices
Authors: Kaczorek Tadeusz
Published: April 2007

Computation of Realizations Composed of Dynamic and Static Parts of Improper Transfer Matrices

The problem of computing minimal realizations of a singular system decomposed into a standard dynamical system and a static system of a given improper transfer matrix is formulated and solved. A new notion of the minimal dynamical-static realization is introduced. It is shown that there always exists a minimal dynamical-static realization of a given improper transfer matrix. A procedure for the computation of a minimal dynamical-static realization for a given improper transfer matrix is proposed and illustrated by a numerical example.
A Backstepping Approach to Ship Course Control
Authors: Witkowska Anna , Tomera Miroslaw , Śmierzchalski Roman
Published: April 2007

A Backstepping Approach to Ship Course Control

As an object of course control, the ship is characterised by a nonlinear function describing static manoeuvring characteristics that reflect the steady-state relation between the rudder deflection and the rate of turn of the hull. One of the methods which can be used for designing a nonlinear ship course controller is the backstepping method. It is used here for designing two configurations of nonlinear controllers, which are then applied to ship course control. The parameters of the obtained nonlinear control structures are tuned to optimise the operation of the control system. The optimisation is performed using genetic algorithms. The quality of operation of the designed control algorithms is checked in simulation tests performed on the mathematical model of a tanker. In order to obtain reference results to be used for comparison with those recorded for nonlinear controllers designed using the backstepping method, a control system with the PD controller is examined as well.
Zooplankton phosphorus excretion in Swarzędzkie Lake (Western Poland) and its influence on phytoplankton
Authors: Kowalczewska-Madura Katarzyna , Gołdyn Ryszard , Szyper Halina
Published: April 2007

Zooplankton phosphorus excretion was studied in Swarzędzkie Lake in 2000-2002. Phosphorus excretion rates were high from spring through autumn, but low in winter. The highest value, 203.7 μgP 1-1 d-1 (vertical profile mean), was recorded in June 2000. The mean rate was 26.6 μgP 1-1 d-1 and was 10 times greater for rotifers than for both cladocerans and copepods. In most months, the calculated phosphorus excretion rate was greater than the sum of tributary external phosphorus loading and internal bottom sediment loading. Nevertheless, the influence of the zooplankton phosphorus excretion rate on yearly phytoplankton abundance, biomass and chlorophyll a was not statistically significant. Yearly variance in phytoplankton variables was best explained by a canonical variable composed of internal loading and zooplankton phosphorus excretion (total redundancy 32.8%).
Impact of neighborhood disadvantage on overt behavior problems during early childhood
Authors: Winslow Emily B. , Shaw Daniel S.
Published: April 2007

Researchers have yet to examine the impact of neighborhood disadvantage on early child behavior problems (BPs) longitudinally. We examined the impact of neighborhood disadvantage on overt BPs in a low‐income, urban sample of 281 African American and European American boys followed longitudinally from toddlerhood to school entry. Measures included census data and maternal report of BPs, sociocultural factors, parental criminality, and maternal depressive symptomatology. After controlling for age 2 overt BPs, family selection variables, and residential instability, neighborhood effects on boys' behavior emerged, but only at age 6 and only at the extreme of neighborhood disadvantage (i.e., underclass). Findings suggest boys in underclass neighborhoods are at risk for overt BPs as they make the transition to elementary school. Aggr. Behav. 33:1–13, 2007.© 2007 Wiley‐Liss, Inc.
Registry‐based case–control study of cancer in California firefighters
Authors: Bates Michael N.
Published: April 2007

Background

There is no consensus whether firefighters are at increased cancer risk for particular cancers. Previous studies have been small, mostly investigated cancer mortality, and suggested increased risks for brain, bladder, testicular, prostate, thyroid and colo‐rectal cancers, leukemia, and melanoma.

Methods

Records of all male cancers registered in California during 1988–2003 were obtained. Firefighters were identified from occupation and industry text fields. Logistic regression analysis used other cancers as controls.

Results

Of the 804,000 eligible records, 3,659 had firefighting as their occupation. Firefighting was associated with testicular cancer (odds ratio = 1.54, 95% confidence interval: 1.18–2.02), melanoma (1.50, 1.33–1.70), brain cancer (1.35, 1.06–1.72), esophageal cancer (1.48, 1.14–1.91), and prostate cancer (1.22, 1.12–1.33).

Conclusions

Use of other‐cancer controls and lack of an occupational history may have biased relative risks towards the null. However, this study, which contained more firefighter cancers than any previous epidemiologic study, produced evidence supporting some prior hypotheses. Am. J. Ind. Med. 50:339–344, 2007. © 2007 Wiley‐Liss, Inc.
Work postures and neck–shoulder pain among orchestra musicians
Authors: Nyman Teresia , Wiktorin Christina , Mulder Marie , Johansson Yvonne Liljeholm
Published: April 2007

Background

The purpose of the present study was to identify associations between a work posture with elevated arm position, duration of active playing time, and neck–shoulder pain among orchestra musicians.

Methods

In this study, with a cross‐sectional study design, a total of 235 subjects from 12 Swedish orchestras were categorized into four exposure groups according to arm position and duration of active playing time. Logistic regression analysis was used to calculate odds ratios (OR) for neck–shoulder pain in the four exposure groups.

Results

A higher prevalence of neck–shoulder pain were found in the groups “elevated arm position, <2 hr per workday” [OR 4.15 (1.30–13.22)], and “elevated arm position, >3 hr per workday” [OR 5.35 (1.96–14.62)] compared to the group “neutral arm position, <2 hr per workday”.

Conclusions

Musicians working in an elevated arm position (e.g., violinists, violists, flutists, and trumpet players) had a higher prevalence of neck–shoulder pain than those working in a more neutral position. Am. J. Ind. Med. 50:370–376, 2007. © 2007 Wiley‐Liss, Inc.
Association studies testing for risk for late‐onset Alzheimer's disease with common variants in the β‐amyloid precursor protein (APP)
Authors: Nowotny Petra , Simcock Xavier , Bertelsen Sarah , Hinrichs Anthony L. , Kauwe John S.K. , Mayo Kevin , Smemo Scott , Morris John C. , Goate Alison
Published: April 2007

Linkage studies have suggested a susceptibility locus for late‐onset Alzheimer's disease (LOAD) on chromosome 21. A functional candidate gene in this region is the β‐amyloid precursor protein (APP) gene. Previously, coding mutations in APP have been associated with early onset Alzheimer's Disease (EOAD). Three copies of APP are associated with AD pathology in Down's syndrome and in EOAD, suggesting that overexpression of APP may be a risk factor for LOAD. Although APP is a strong functional and positional candidate, to date there has been no thorough investigation using a dense map of SNPs across the APP gene. In order to investigate the role of common variation in the APP gene in the risk of LOAD, we genotyped 44 SNPs, spanning 300 kb spanning the entire gene, in a large case‐control series of 738 AD cases and 657 healthy controls. The SNPs showed no association in genotypic or allelic tests, even after stratification for presence or absence of the APOE ϵ4 allele. Haplotype analysis also failed to reveal significant association with any common haplotypes. These results suggest that common variation in the APP gene is not a significant risk factor for LOAD. However, we cannot rule out the possibility that multiple rare variants that increase APP expression or Aβ production might influence the risk for LOAD. © 2007 Wiley‐Liss, Inc.
MECP2 coding sequence and 3′UTR variation in 172 unrelated autistic patients
Authors: Coutinho Ana M. , Oliveira Guiomar , Katz Cécile , Feng Jinong , Yan Jin , Yang Chunmei , Marques Carla , Ataíde Assunção , Miguel Teresa S. , Borges Luís , Almeida Joana , Correia Catarina , Currais António , Bento Celeste , Mota‐Vieira Luísa , Temudo Teresa , Santos Mónica , Maciel Patrícia , Sommer Steve S. , Vicente Astrid M.
Published: April 2007

Mutations in the coding sequence of the methyl‐CpG‐binding protein 2 gene (MECP2), which cause Rett syndrome (RTT), have been found in male and female autistic subjects without, however, a causal relation having unequivocally been established. In this study, the MECP2 gene was scanned in a Portuguese autistic population, hypothesizing that the phenotypic spectrum of mutations extends beyond the traditional diagnosis of RTT and X‐linked mental retardation, leading to a non‐lethal phenotype in male autistic patients. The coding region, exon–intron boundaries, and the whole 3′UTR were scanned in 172 patients and 143 controls, by Detection of Virtually All Mutations‐SSCP (DOVAM‐S). Exon 1 was sequenced in 103 patients. We report 15 novel variants, not found in controls: one missense, two intronic, and 12 in the 3′UTR (seven in conserved nucleotides). The novel missense change, c.617G > C (p.G206A), was present in one autistic male with severe mental retardation and absence of language, and segregates in his maternal family. This change is located in a highly conserved residue within a region involved in an alternative transcriptional repression pathway, and likely alters the secondary structure of the MeCP2 protein. It is therefore plausible that it leads to a functional modification of MeCP2. MECP2 mRNA levels measured in four patients with 3′UTR conserved changes were below the control range, suggesting an alteration in the stability of the transcripts. Our results suggest that MECP2 can play a role in autism etiology, although very rarely, supporting the notion that MECP2 mutations underlie several neurodevelopmental disorders. © 2007 Wiley‐Liss, Inc.
Low brain‐derived neurotrophic factor (BDNF) levels in serum of Huntington's disease patients
Authors: Ciammola A. , Sassone J. , Cannella M. , Calza S. , Poletti B. , Frati L. , Squitieri F. , Silani V.
Published: April 2007

Huntington's disease (HD) is a neurodegenerative disorder characterized by motor, cognitive, and psychiatric symptoms and by a progressive degeneration of neurons in basal ganglia and in brain cortex. Brain‐derived neurotrophic factor (BDNF) is a pro‐survival factor for striatal neurons. Some evidence implicates a brain BDNF deficiency, related to mutated huntingtin expression, in the selective vulnerability of striatal neurons in HD. We compared BDNF serum levels in 42 patients with HD (range 28–72 years, mean age 51.9 ± 11.5), and 42 age‐matched healthy subjects (range 25–68 years, mean age 48.2 ± 12.5). We evaluated the potential relationship between BDNF serum levels, CAG repeat number (range 40–54, mean 44.8 ± 3.4) and duration of illness (range 6–228 months, mean 103.6 ± 62.1). Serum BDNF levels were significantly lower in patients than in age‐matched healthy subjects. Lower BDNF levels were associated with a longer CAG repeat length and a longer duration of illness. Severity of the illness, as assessed by the Unified Huntington's Disease Rating Scale (UHDRS) motor and cognitive scores, was negatively related to serum BDNF levels. These results in vivo confirm that the huntingtin mutation causes BDNF production to decline and show that the BDNF deficiency is detectable in HD patients' sera. Further studies on a larger sample size should confirm whether BDNF concentrations in patients' serum could be a useful clinical marker related to the patients' disease phenotype. © 2007 Wiley‐Liss, Inc.
Sustained attention and response inhibition in boys with fragile X syndrome: Measures of continuous performance
Authors: Sullivan Kelly , Hatton Deborah D. , Hammer Julie , Sideris John , Hooper Stephen , Ornstein Peter A. , Bailey Donald B.
Published: April 2007

Sustained attention and response inhibition were examined in boys with full mutation fragile X syndrome (FXS) using adapted visual and auditory continuous performance tests (CPTs). Only 61% of 56 boys with visual CPT data and 54% of 52 boys with auditory data were able to demonstrate sufficient understanding to complete the visual and auditory CPTs, respectively. Mental age (MA) predicted whether boys with FXS were able to demonstrate understanding of the CPTs. The performance of boys with FXS who were able to complete the CPTs was compared to a sample of boys without disabilities matched on MA. Boys with FXS demonstrated similar or smaller declines in sustained attention over task time than their MA‐matched peers on the visual and auditory CPTs, respectively, but consistently demonstrated greater declines in response inhibition over task time than their MA‐matched peers. There were no differences between groups for response time of hits. Higher MAs consistently predicted better sustained attention and response inhibition over task time on the visual and auditory CPTs. Furthermore, boys taking psychotropic medication performed better at the beginning of most tasks, although their performance deteriorated at a faster rate over time, and boys rated as meeting diagnostic criteria for ADHD‐hyperactive type had more difficulty over task time with response inhibition on the auditory CPT. For both boys with FXS and their MA matches, performance was better on the visual CPT than on the auditory CPT though this effect may be attributable to a number of factors other than the modality. © 2007 Wiley‐Liss, Inc.
Investigation of parent‐of‐origin effects in ADHD candidate genes
Authors: Kim Jang Woo , Waldman Irwin D. , Faraone Stephen V. , Biederman Joseph , Doyle Alysa E. , Purcell Shaun , Arbeitman Lori , Fagerness Jesen , Sklar Pamela , Smoller Jordan W.
Published: April 2007

Attention deficit hyperactivity disorder (ADHD) is a common early‐onset childhood disorder with a strong genetic component. Results from previous studies have suggested that there may be a parent‐of‐origin effect for ADHD candidate genes. In particular, a recent investigation identified a pattern of paternal over‐transmission of risk alleles for nine ADHD candidate genes. We examined this phenomenon in a sample of 291 trios for five genes previously associated with ADHD (HTR1B, SNAP‐25, DRD5, DAT1, and BDNF). Using a dense map of markers and two analytic methods in this relatively large family‐based sample, we do not find any evidence for significant paternal over‐transmission of risk alleles in these candidate loci. Thus, we conclude that a substantial parent‐of‐origin effect is unlikely for these leading ADHD candidate genes. © 2007 Wiley‐Liss, Inc.
High‐strain deformation of polyethylenes in plane‐strain compression at elevated temperatures
Authors: Lezak E. , Bartczak Z.
Published: April 2007

The deformation and recovery behavior of several polyethylenes and ethylene‐based copolymers with various molecular architectures and a broad range of molecular masses and molecular mass distributions was studied. Because of the differences in the molecular characteristic, this series exhibited a relatively broad range of crystallite sizes and crystallinity levels. The samples were subjected to high strain compression under plane‐strain conditions at the elevated temperature of 80°C. The unloading of the compressed samples led to substantial nonelastic recovery of the strain. The stress–strain and recovery behavior was related to the molecular parameters. The results confirmed the common deformation scheme with four crossover points related to the activation of subsequent deformation mechanisms, as proposed by Strobl. Although the critical strains, related to the activation of deformation of the crystalline component, are invariant, the critical strain of the last point, which is related to the activation of chain disentanglement in the amorphous component, depends on the temperature of deformation. That critical strain decreases from 1.0 to approximately 0.8–0.9 as the temperature of deformation increases from room temperature to 80°C. This shift results from an increase in the chain mobility with increasing temperature, and this makes modification of the molecular network through chain disentanglements easier. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 14–24, 2007
Dispersions of organically modified boehmite particles and a carboxylated styrene–butadiene latix: A simple way to nanocomposites
Authors: Florjańczyk Zbigniew , Dębowski Maciej , Wolak Andrzej , Malesa Monika , Płecha Justyna
Published: April 2007

Boehmite particles modified with organic ligands were prepared through the reaction of boehmite with acrylic acid or diethylphosphoric acid (formed in situ from triethyl phosphate). The chemical structures of these particles were determined, and it was shown that they formed stable aqueous dispersions with a particle size lower than 200 nm (average diameter = 40–100 nm, depending on the method of modification) for more than 90% of the population. These nanoparticle dispersions were mixed with carboxylated styrene–butadiene latex, and after water evaporation, homogeneous composites were obtained when the modifier concentration was in the range of 0.5–3 wt %. The mechanical properties of the composites were improved with respect to those of the unmodified rubber (tensile strength up to 200% and elongation at break up to 40%). The modifiers also improved some mechanical properties of rubbers cured with sulfur/N‐cyclohexylbenzothiazole‐2‐sulfenamide/ZnO/stearic acid or ZnO/stearic acid systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 80–88, 2007