Relation between implant/abutment vertical misfit and torque loss of abutment screws

This study investigated whether there is a direct correlation between the level of vertical misfit at the abutment/implant interface and torque losses (detorque) in abutment screws. A work model was obtained from a metal matrix with five 3.75 x 9 mm external hex implants with standard platform (4.1 mm). Four frameworks were waxed using UCLA type abutments and one-piece cast in commercially pure titanium. The misfit was analyzed with a comparator microscope after 20 Ncm torque. The highest value of misfit observed per abutment was used. The torque required to loose the screw was evaluated using a digital torque meter. The torque loss values, measured by the torque meter, were assumed as percentage of initial torque (100%) given to abutment screws. Pearson's correlation (α=0.05) between the misfit values (29.08 ± 8.78 µm) and the percentage of detorque (50.71 ± 11.37%) showed no statistically significant correlation (p=0.295). Within the limitations of this study, it may be concluded that great vertical misfits dot not necessarily implies in higher detorque values.

Emprego de regras de associação para extração de padrões mercadológicos de touros Nelore com avaliação genética

Objetivou-se com este trabalho utilizar regras de associação para identificar forças de mercado que regem a comercialização de touros com avaliação genética pelo programa Nelore Brasil. Essas regras permitem evidenciar padrões implícitos nas transações de grandes bases de dados, indicando causas e efeitos determinantes da oferta e comercialização de touros. Na análise foram considerados 19.736 registros de touros comercializados, 17 fazendas e 15 atributos referentes às diferenças esperadas nas progênies dos reprodutores, local e época da venda. Utilizou-se um sistema com interface gráfica usuário-dirigido que permite geração e seleção interativa de regras de associação. Análise de Pareto foi aplicada para as três medidas objetivas (suporte, confiança e lift) que acompanham cada uma das regras de associação, para validação das mesmas. Foram geradas 2.667 regras de associação, 164 consideradas úteis pelo usuário e 107 válidas para lift ≥ 1,0505. As fazendas participantes do programa Nelore Brasil apresentam especializações na oferta de touros, segundo características para habilidade materna, ganho de peso, fertilidade, precocidade sexual, longevidade, rendimento e terminação de carcaça. Os perfis genéticos dos touros são diferentes para as variedades padrão e mocho. Algumas regiões brasileiras são nichos de mercado para touros sem registro genealógico. A análise de evolução de mercado sugere que o mérito genético total, índice oficial do programa Nelore Brasil, tornou-se um importante índice para comercialização dos touros. Com o uso das regras de associação, foi possível descobrir forças do mercado e identificar combinações de atributos genéticos, geográficos e temporais que determinam a comercialização de touros no programa Nelore Brasil.

Caracterização mecânica e térmica da borracha natural formulada e vulcanizada dos clones: GT 1, IAN 873, PB 235 e RRIM 600

Neste trabalho estudou-se o desempenho mecânico e térmico de compostos de borracha natural (Hevea brasiliensis) de 4 diferentes clones (GT 1, IAN 873, PB 235 e RRIM 600) cultivados no Estado de São Paulo, assim como de uma mistura destes clones e de uma borracha comercial, GEB-1. Estas borrachas foram formuladas e vulcanizadas com tempos de 5, 7 e 9 minutos. A caracterização foi realizada por calorimetria exploratória diferencial, termogravimetria, ensaios de resistência à tração, análise dinâmico-mecânica, medidas de dureza Shore A, microscopia eletrônica de varredura e espectroscopia na região do infravermelho. Os resultados permitiram concluir que o tempo de vulcanização e o tipo de clone não influenciaram na temperatura de transição vítrea (Tg) dos compostos. Os valores de Tg obtidos por DMA foram de cerca de -62 °C, e os resultados ensaios de dureza apresentaram valores próximos de 60 para todos os compostos estudados. Os ensaios de resistência à tração mostraram que o melhor desempenho mecânico foi obtido pelo clone RRIM 600. De acordo com os resultados obtidos neste trabalho, todos os clones atingiram as propriedades reportadas na literatura, podendo ser utilizados, em princípio, nas indústrias de artefatos de borracha separadamente ou na forma de mistura.

Eletrodo de hidrogênio: o que há nos livros didáticos além de E¸ = 0?

The results of an exercise on electrochemistry for General Chemistry students are presented. The difficulty encountered by students in predicting the shift in the potential of the hydrogen electrode under non-standard conditions prompted a search in textbooks on how the subject is developed. Besides several instances of inconsistencies in defining the standard state, such as including the temperature in the definition, a number of incorrect depictions of the hydrogen electrode were discovered. Of the 28 General Chemistry books, 16 Physical Chemistry books and 24 Internet pages, 30, 20 and 46%, respectively, showed devices that would not work in practice.

Saúde e capacidade para o trabalho de eletricitários do Estado de São Paulo

Apesar dos elevados riscos à saúde e capacidade para o trabalho dos eletricitários, há carência de estudos sobre o tema no Brasil. O objetivo desse estudo é identificar o perfil de saúde e capacidade para o trabalho de eletricitários de São Paulo. Foi feito um estudo transversal junto a 475 trabalhadores de uma empresa do setor eletricitário. A coleta de dados foi por meio de questionários sobre capacidade para o trabalho, estado de saúde, estresse no trabalho, atividade física, dependência ao tabaco e ao álcool. A consistência interna das escalas foi avaliada usando o coeficiente alfa de Cronbach. Foi feita análise descritiva por meio das médias, desvios-padrão, valores mínimos e máximos dos escores e proporções para as variáveis qualitativas. O estado de saúde dos trabalhadores apresentou pontuação elevada nas dimensões analisadas, com médias entre 72,8 a 91,2 (escore de 0,0 a 100,0 pontos). A capacidade para o trabalho teve pontuação elevada, com média de 41,8 (escore de 7,0 a 49,0 pontos). Concluiu-se que os trabalhadores da população de estudo apresentaram elevados padrões do estado de saúde e da capacidade para o trabalho. Sugere-se o desenvolvimento de estudos longitudinais para avaliar relações causais e a existência de efeito do trabalhador sadio.

Working at night and work ability among nursing personnel: when precarious employment makes the diVerence

Purpose To test the association between night work and work ability, and verify whether the type of contractual employment has any inXuence over this association. Methods Permanent workers (N = 642) and workers with precarious jobs (temporary contract or outsourced; N = 552) were interviewed and Wlled out questionnaires concerning work hours and work ability index. They were classiWed into: never worked at night, ex-night workers, currently working up to Wve nights, and currently working at least six nights/2-week span. Results After adjusting for socio-demography and work variables, current night work was signiWcantly associated with inadequate WAI (vs. day work with no experience in night work) only for precarious workers (OR 2.00, CI 1.01- 3.95 and OR 1.85, CI 1.09-3.13 for those working up to Wve nights and those working at least six nights in 2 weeks, respectively). Conclusions Unequal opportunities at work and little experience in night work among precarious workers may explain their higher susceptibility to night work

Work and excessive sleepiness among Brazilian evening high school students: effects on days off

Previous studies have revealed that students who work and study build up sleep deficits during the wrkweek, which can trigger a sleep rebound during days off. The objective of this study was to investigate the impact of working on sleepiness during days off working / non-working on sleepiness days off among high school students. The study population, aged 14-21 years, attended evening classes in São Paulo, Brazil. For the study, the students completed questionaires on living conditions, health, and work; wore actigraphs; and completed the Karolinska Sleepiness Scale (KSS). To predict sleepiness, a logistic regression analysis was performed. Excessive sleepiness was observed on the first day off among working students. Results suggest that working is a significant predictor for sleepiness and that two shifts of daily systematic activities, study and work, might lead to excessive daytime sleepiness on the first day off. Further, this observed excessive sleepiness may reflect the sleep debt accumulated during the workweek

Stress at work among electric utility workers

In the last decades there was an increase in stress at work and its effects on workers' health. These issues are still little studied in the electric utility sector. This study aims to evaluate factors associated with stress at work and to verify its associations with health status among workers of an electric company in São Paulo State, Brazil. A cross-sectional study was conducted with 474 subjects (87.5% of the eligible workers). Data were collected using self-reported questionnaires. A descriptive analysis, a multiple linear hierarchical regression analysis and a correlation analysis were performed. The majority of participants were males (91.1%) and the mean age was 37.5 yr. The mean score of stress level was 2.3 points (scale ranging from 1.0 to 5.0). Hierarchical multiple analyses showed that: regular practice of physical activities (p=0.025) and individual monthly income (p=0.002) were inversely associated with stress level; BMI was marginally associated with the stress level (p=0.074). The demographic characteristics were not associated with stress. Stress at work was significantly associated with physical and mental health status (p<0.001). To improve health of electric utility workers, actions are suggested to decrease stress by remuneration and an appropriate practice of physical activity aiming reduction of BMI

Effects of naps at work on the sleepiness of 12-hour night shift nursing personnel

Background and objective: The purpose of the present study was to evaluate the effects of a nap at work on the sleepiness of 12-hour, night-shift (registered and assistant) nursing personnel.Methods: Twelve nurses filled out daily logs, the Karolinska Sleepiness Scale (KS), and wore wrist actigraphs for two periods of four continuous days.Results: Mean nap duration during the night shifts was 138.3 (SD+39.8) minutes. The mean sleepiness level assessed by the KS score was lower, 3.3 (SD±1.6), when the nap was taken during the first span (00:01 - 03:00h) of the night shift, compared with 6.6 (SD±1.0) when there was no nap. The mean sleepiness level assessed by the KS score was also lower, 3.6 (SD±0.9), when the nap was taken during the second span (03:01 - 06:00h) of the night shift, compared with 7.0 (SD±1.1) when there was no nap. Thus, napping either during the first or second part of the night shift reduces sleepiness of 12-hour, night-shift nursing personnel. Moreover, the mean duration of the first sleep episode after night work was longer in those who did not nap than in those who did. Conclusions: The results of this study show that napping during the 12-hour, night-shift results in less sleepiness at work and less need for recovery sleep after work

Fatores associados à recuperação nutricional de crianças em programa de suplementação alimentar

OBJETIVOS: Identificar os fatores associados à recuperação nutricional de crianças inscritas no Programa de Incentivo ao Combate às Carências Nutricionais (ICCN) no Município de Mogi das Cruzes. MÉTODOS: Foi realizado um ensaio institucional não controlado com 570 crianças inscritas no ICCN, que foram seguidas de julho de 1999 a julho de 2001. O estado nutricional foi avaliado segundo índice altura/idade, sendo consideradas eutróficas as crianças com escore z > - 1; de risco as que apresentaram z > - 2 e < - 1; desnutridas moderadas aquelas com z < - 2 e > - 3; e desnutridas graves as que apresentavam z < - 3. O impacto do ICCN foi analisado através de modelo multivariado com o uso de equações de estimação (GEE - Generalized Estimating Equations), sendo considerado significativo p<0,05. RESULTADOS/CONCLUSÃO: Ao final do seguimento, houve a melhora nutricional das crianças, com um gradiente, sendo maior a recuperação quanto maior a deficiência nutricional inicial. Observaram-se ganhos em altura de 1,12, 0,82, 0,57 e 0,45 desvios-padrão para as desnutridas graves, moderadas, em risco nutricional e eutróficas, respectivamente. Os fatores associados à evolução nutricional das crianças desnutridas foram a idade de 12 a 24 meses ao ingressar no ICCN, o peso ao nascer igual ou superior a 3 kg e o aleitamento materno. Os fatores associados negativamente à evolução nutricional neste grupo foram idade da mãe entre 20 a 40 anos e a ausência de trabalho remunerado materno. Para as crianças em risco, a renda familiar também se mostrou associada à melhor evolução nutricional. A experiência do ICCN em Mogi das Cruzes sugere que os programas de suplementação alimentar têm papel relevante na recuperação nutricional de desnutridos

Free expanding cloud of cold atoms as an atomic standard: Ramsey fringes contrast

A compact frequency standard based on an expanding cold (133)CS cloud is under development in our laboratory. In a first experiment, Cs cold atoms were prepared by a magneto-optical trap in a vapor cell, and a microwave antenna was used to transmit the radiation for the clock transition. The signal obtained from fluorescence of the expanding cold atoms cloud is used to lock a microwave chain. In this way the overall system stability is evaluated. A theoretical model based on a two-level system interacting with the two microwave pulses enables interpretation for the observed features, especially the poor Ramsey fringes contrast. (C) 2008 Optical Society of America.

Horizontal subsurface flow constructed wetlands for mitigation of ametryn-contaminated water

The feasibility of using constructed wetlands (CWs) for the mitigation of pesticide runoff has been studied in the last decade. However, a lack of related data was verified when subsurface flow constructed wetlands (SSF CWs) are considered for this purpose. In the present work, SSF CWs were submitted to continuous ametryn addition and evaluated during an I I-week period, with the aim of determining the feasibility of these systems for mitigation of contaminated water. Ametryn was not added to one CW cell in order to provide a control for the experiments. Monitoring of treatment performance was executed by standard water quality parameters, ametryn chromatography quantification and macrophyte (Typha latifolia L) nutritional and agronomic property analysis. Results indicated that 39% of the total initially added amount of ametryn was removed, transferred or transformed. Herbicide metabolism and mineralisation were carried out by chemical and biological mechanisms. No statistic differences were observed in nutritional contents found in the T. latifolia crops of the CWs after the experimental period. Moreover, the biomass production (one valuable source of renewable energy) was equal to 3.3 t.ha(-1) (dry matter) in wetland cells. It was concluded that constructed wetland systems are capable of mitigating water contaminated with ametryn, acting as buffer filters between the emission sources and the downstream superficial water bodies.