Influence of magnetically-induced E-fields on cardiac electric activity during MRI: A modeling study

In modern magnetic resonance imaging (MRI), patients are exposed to strong, time-varying gradient magnetic fields that may be able to induce electric fields (E-fields)/currents in tissues approaching the level of physiological significance. In this work we present theoretical investigations into induced E-fields in the thorax, and evaluate their potential influence on cardiac electric activity under the assumption that the sites of maximum E-field correspond to the myocardial stimulation threshold (an abnormal circumstance). Whole-body cylindrical and planar gradient coils were included in the model. The calculations of the induced fields are based on an efficient, quasi-static, finite-difference scheme and an anatomically realistic, whole-body model. The potential for cardiac stimulation was evaluated using an electrical model of the heart. Twelve-lead electrocardiogram (ECG) signals were simulated and inspected for arrhythmias caused by the applied fields for both healthy and diseased hearts. The simulations show that the shape of the thorax and the conductive paths significantly influence induced E-fields. In healthy patients, these fields are not sufficient to elicit serious arrhythmias with the use of contemporary gradient sets. However, raising the strength and number of repeated switching episodes of gradients, as is certainly possible in local chest gradient sets, could expose patients to increased risk. For patients with cardiac disease, the risk factors are elevated. By the use of this model, the sensitivity of cardiac pathologies, such as abnormal conductive pathways, to the induced fields generated by an MRI sequence can be investigated. (C) 2003 Wiley-Liss, Inc.

Environmental conditions and variation in levels of sun exposure among children in child care

Sun exposure in childhood is I of the risk factors for developing skin cancer, yet little is known about levels of exposure at this age. This is particularly important in countries with high levels of ultraviolet radiation. (UVR) such as Australia. Among 49 children 3 to 5 years of age attending child care centers, UVR exposure was studied under 4 conditions in a repeated measures design; sunny days, cloudy days, teacher's instruction to stay in the shade, and a health professionals instruction to apply sunscreen. Three different data collection methods were employed: (a) completion of questionnaire or diary by parents and researcher, (b) polysulphone dosimeter readings, and (c) observational audits (video recording). Results of this study indicated that more than half the children had been sunburnt (pink or red) and more than a third had experienced painful sunburn (sore or tender) in the last summer. Most wore short sleeve shirts, short skirts or shorts and cap, that do not provide optimal levels of skin protection. However, sunscreen was applied to all exposed parts before the children went out to the playground. Over the period of I hr (9-10 a.m.) the average amount of time children spent in full sun was 22 min. On sunny days there was more variation across children in the amount of sun exposure received. While the potential amount of UVR exposure for young children during the hour they were outside on a sunny day was 1.45 MED (Minimum Erythemal Dose), they received on average 0.35 MED, which is an insufficient amount to result in an erythemal response on fair skin even without the use of sunscreen.

Quantum theory of the far-off-resonance continuous-wave Raman laser: Heisenberg-Langevin approach

We present the quantum theory of the far-off-resonance continuous-wave Raman laser using the Heisenberg-Langevin approach. We show that the simplified quantum Langevin equations for this system are mathematically identical to those of the nondegenerate optical parametric oscillator in the time domain with the following associations: pump pump, Stokes signal, and Raman coherence idler. We derive analytical results for both the steady-state behavior and the time-dependent noise spectra, using standard linearization procedures. In the semiclassical limit, these results match with previous purely semiclassical treatments, which yield excellent agreement with experimental observations. The analytical time-dependent results predict perfect photon statistics conversion from the pump to the Stokes and nonclassical behavior under certain operational conditions.

Otimização do layout de marcenarias no sul do espírito santo baseado em parâmetros ergonômicos e de produtividade

Este estudo foi realizado em três marcenarias no sul do Estado do Espírito Santo, com o objetivo de analisar o layout e propor mudanças que otimizem o funcionamento harmônico entre o local de trabalho e o trabalhador, considerando-se fatores ergonômicos, fluxo de produção e produtividade. A coleta de dados foi feita analisando-se as condições do ambiente de trabalho (clima, ruído, iluminação) e aplicando uma entrevista para avaliar as condições gerais e de segurança no trabalho. O layout foi avaliado por medições, observação da sequência de trabalho nas máquinas e aplicação do software AutoCAD 2000. Os resultados indicaram que o Índice de Bulbo Úmido e o Termômetro de Globo estavam de acordo com a Norma Regulamentadora nº 15 (atividade moderada), sendo de 26,38 ºC, em média. Os níveis médios de ruído foram de 87,48 dB (A), acima do permitido para uma jornada de 8 h diárias (NR 15). A luminosidade média, encontrada em duas marcenarias, ficou acima da faixa de iluminação mínima recomendada para esse trabalho de maquinarias (NBR 5413/92). Todas as marcenarias tinham disposição desordenada do maquinário em razão da sequência lógica de trabalho, presença de pilastras e resíduos na área útil e de passagem, piso desnivelado, falta de rampas para acesso aos galpões, manutenção de máquinas e equipamentos de forma incorreta, falhas no telhado e ausência de bancadas para facilitar a adoção de uma melhor postura durante o manuseio das peças.

Adequação e verificação de procedimentos para determinação de mercúrio em amostras de fígado e rim de rato utilizando a técnica CV-GF AAS

O mercúrio é um elemento que ainda necessita constante monitoramento devido sua capacidade tóxica em concentrações em níveis de traço com possibilidade de contaminação e exposição por uma variedade de formas e compostos presentes no ambiente. Esse estudo possuiu como objetivo a obtenção de um procedimento simplificado e eficiente para a determinação de teores de mercúrio em tecidos de rato Wistar a partir da otimização de um método de determinação, utilizando um sistema de geração de vapor frio acoplado a espectrometria de absorção atômica com forno de grafite (CV-GF AAS). Houve a comparação entre métodos de digestão, comparação de métodos de amalgamação, otimização, verificação do método a partir da obtenção de figuras de mérito e análise de amostras de fígado e rins de ratos tratados com exposição crônica ao mercúrio. Os resultados comprovaram que o método de digestão em bloco digestor, a utilização de amalgamação por recobrimento de tubo em ouro em conjunto com rede de ouro e adição pré-análise à solução de simeticona e isopropanol apresentou os melhores resultados, com teores de recuperação médios entre 92 e 114 %, viabilizando a utilização do procedimento proposto.

Avaliação do risco cardiovascular e fatores associados na população de Anchieta-ES

As doenças cardiovasculares são as principais causas de morte no mundo e muitos constituem os fatores de risco para essas doenças. Objetiva-se investigar o risco cardiovascular para evento coronariano agudo de acordo com o escore de Framingham em população adulta do município de Anchieta-ES. Estudo transversal com dados da linha de base do estudo Carmen Anchieta, iniciado em 2010. A amostra foi sistemática e estratificada por micro área de abrangência das Unidades de Saúde da Família, sexo e idade e 539 pessoas foram selecionadas para este estudo por terem os dados completos. Os dados foram coletados mediante entrevista no domicílio, exames laboratoriais de sangue, verificação da pressão arterial e antropometria nas Unidades de Saúde. As variáveis de exposição constituem escolaridade, raça-cor, renda familiar, residência em espaço urbano ou rural, estado civil, consumo de álcool, atividade física, índice de massa corpórea e autoavaliação de saúde. Para a classificação do risco cardiovascular utilizou-se o escore de Framingham. Foi realizada análise bivariada e regressão logística multinomial para testar a hipótese de associação entre as variáveis e o risco cardiovascular mediante o cálculo da razão de chances (RC) e intervalo de confiança de 95%. O nível de significância foi p < 0,05. Os resultados mostraram predominância de pessoas nas faixas etárias entre 25 a 54 anos, casadas, pardas, ensino fundamental incompleto, baixa renda, insuficientemente ativas, com sobrepeso e obesidade em mais da metade da amostra, 38,6% ingeriam bebida alcoólica e 55,7% relaram saúde muito boa ou boa. O risco cardiovascular foi baixo em 74%, intermediário em 11,3% e elevado em 14,7%. Estiveram associados ao risco cardiovascular intermediário ser analfabeto 8,89 (3,193-24,756), ter ensino fundamental incompleto 3,17 (1,450-6,964) e ser viúvo/ separado 2,55 (1,165-5,583) e associados ao risco cardiovascular elevado ser analfabeto 11,34 (4,281-30,049), ensino fundamental incompleto 2,95 (1,362-6,407) e autoavaliação da saúde muito ruim/ruim 2,98 (1,072-8,307) e regular 2,25 (1,294-3,925). Ser solteiro constituiu fator de proteção 0,40 (0,183-0,902).

Multi-level governance and social cohesion in the European Union: the assessment of local agents, a study case inside Galicia

Implementing multi-level governance has been a key priority in EU cohesion policy. This study assesses the perceived achievements and shortcomings in implementing European Social Fund by analyzing the deficits and weaknesses as well as the poor participation of local agents who are in direct contact with the beneficiaries in order to design and implement this fund, which is the main financial instrument of EU social policy.

Damage level of the two-spotted spider mite Tetranychus urticae Koch (acari: tetranychidae) in soybeans

Among phytophagous spider mites, the two-spotted spider mite Tetranychus urticae Koch, 1836 is one of the most important agricultural pests, not only because of the damage it causes, but also because it has a wide host range, infesting many commercial crops such as leafy greens, cotton, beans, and soybeans, among others. This study was carried out in a greenhouse of the Faculdade de Ciências Agrárias (FCA) of the Universidade Federal da Grande Dourados (UFGD), located in the city of Dourados, state of Mato Grosso do Sul. The experiment was arranged in a randomized block design with 5 treatments and 4 replicates. The treatments consisted of 5 levels in percentage of chlorotic symptoms (indicating mite damage): 0%, 25%, 50%, 75%, and 100%. All of the characteristics evaluated, except for number of pods per plant, the number of seeds per plant, the total weight (productivity), and the weight of 1000 seeds, were significantly influenced by the different levels of chlorotic symptoms. The economic damage level for the two-spotted spider mite Tetranychus urticae, according to the equation y = 66.63-0.51 x, based on the price of US$ 11.00 per bag of soybeans and a control cost of US$ 16.00, would be 15.80% chlorotic symptoms. At a price of US$ 29.00 per bag with the same control cost, the economic damage level would be 13% of chlorotic symptoms.

Prevalence of periodontal disease in dogs and owners' level of awareness - a prospective clinical trial

Periodontal disease (PD) is widely known among veterinarians for its high prevalence and serious consequences to the dogs. The objective of this study was to assess the occurrence of PD in dogs that live in the micro-region of Viçosa, treated at the Veterinary Hospital of the Federal University of Viçosa (HVT - Hospital Veterinário da Universidade Federal de Viçosa), as well as to assess how aware of this disease dog owners are. In order to do so, all dogs treated at the HVT from March 10th, 2009 to November 30th, 2009, on alternate days, had their oral cavities examined. Medical history data, such as age, type of food, main complaint and owner consent, halitosis, presence of dental calculus, inflammation and gingival recession and tooth loss, were collected. A prevalence of 88.67% was found for PD in dogs referred to the HVT, and 2.67% were referred due to this disease. Of all the owners who participated in the study, 43.83% knew about periodontal disease and of these 17.46% made use of some type of prevention or treatment. Therefore, periodontal disease is highly prevalent and the owners are not aware of the disease. Thus, a dog owner clarification program on periodontal disease is needed in the area where HVT-UFV operates.

An optimal level of technology reliance on foreign partners in a global sourcing partnership: components procurement, technology management and market performance

Existing studies on global sourcing strategy have implicitly adopted a cJosed-systems perspective in which sourcing activities are managed within a multinational company across national boundaries. Produd and process innovations and components procurement that are jointly managed by a consortium of cooperating firms have not been examined. In this paper, we empiricallyexamine the issues concerning sourcing partnerships in an open-systems perspective. Findings suggest that even in a sourcing partnership arrangement with a foreign supplier, the principal firm's ability to procure and control the supply of major components has a positive bearing on its market performance.

The undergraduate level (1st study cycle) as a fundamental platform/standard for the development of Urban and Regional Planning in higher education programs

LUDA is a research project of Key Action 4 "City of Tomorrow & Cultural Heritage" of the programme "Energy, Environment and Sustainable Development" within the Fifth Framework Programme of the European Commission

Statistical classification of road pavements using near field vehicle rolling noise measurements

Low noise surfaces have been increasingly considered as a viable and cost-effective alternative to acoustical barriers. However, road planners and administrators frequently lack information on the correlation between the type of road surface and the resulting noise emission profile. To address this problem, a method to identify and classify different types of road pavements was developed, whereby near field road noise is analyzed using statistical learning methods. The vehicle rolling sound signal near the tires and close to the road surface was acquired by two microphones in a special arrangement which implements the Close-Proximity method. A set of features, characterizing the properties of the road pavement, was extracted from the corresponding sound profiles. A feature selection method was used to automatically select those that are most relevant in predicting the type of pavement, while reducing the computational cost. A set of different types of road pavement segments were tested and the performance of the classifier was evaluated. Results of pavement classification performed during a road journey are presented on a map, together with geographical data. This procedure leads to a considerable improvement in the quality of road pavement noise data, thereby increasing the accuracy of road traffic noise prediction models.

Effects of exposure to formaldehyde and tobacco smoking on genotoxicity biomarkers

Formaldehyde (FA) is a colour less gas widely used in the industry and hospitals as an aqueous solution, formalin. It is extremely reactive and induces various genotoxic effects in proliferating cultured mammalian cells. Tobacco smoke has been epidemiologically associated to a higher risk of development of cancer, especially in the oral cavity, larynx and lungs, as these are places of direct contact with many carcinogenic tobacco’s compounds. Approximately 90% of human cancers originate from epithelial cells. Therefore, it could be argued that oral epithelial cells represent a preferred target site for early genotoxic events induced by carcinogenic agents entering the body via inhalation and ingestion. The cytokinesis-blocked micronucleus assay (CBMN) in human lymphocytes is one of the most commonly used methods for measuring DNA damage, namely the detection of micronucleus, nucleoplasmic bridges, and nuclear buds.

Occupational exposure to formaldehyde: effects of years of exposure in the frequency of micronucleus

Formaldehyde: an important industrial compound used in the manufacture of synthetic resins and chemical compounds such as lubricants and adhesives; also applied as a disinfectant, preservative and in cosmetics productions; relevant workplace exposure to FA also occurs in anatomy, pathology and in mortuaries; classified by IARC as carcinogenic to humans (Group 1), based on sufficient evidence in humans and experimental animals; manifold in vitro studies indicated that FA can induce genotoxic effects in proliferating cultured mammalian cells. Aim of the study: to evaluate if years of exposure induced a genotoxic biomarkers increase, namely MN in lymphocytes and buccal cells, in workers occupationally exposed to FA (factory and pathology anatomy laboratory).