Effect of Al(PO3)(3) content on physical, chemical and optical properties of fluorophosphate glasses for 2 mu m application

The effect of Al(PO3)(3) content on physical, chemical and optical properties of fluorophosphate glasses for 2 mu m application, such as thermal stability, chemical durability, surface hardness, absorption spectra and emission spectra, is investigated. With the increment of Al(PO3)(3) content, the thermal stability characterized by the gap of T-g and T,, increases first and then decreases, and reaches the maximum level containing 5 mol% Al(PO3)(3) content. The density and chemical durability decrease monotonously with the introduction of Al(PO3)(3) content increasing, while the refractive index and surface hardness increase. Above properties of fluorophosphate glasses are also compared with fluoride glasses and phosphate glasses. The Judd-Ofelt parameters, absorption and emission cross sections are discussed based on the absorption spectra of Tm-doped glasses. The emission spectra are also measured and the 1.8 mu m fluorescence of the sample is obvious indicating that it is suitable to 2 mu m application. (c) 2008 Elsevier B.V. All rights reserved.

Capacidade antioxidante e a prática de atividade física em indivíduos com lesão medular cervical

A lesão medular está associada a uma série de alterações bioquímicas e decomposição corporal. O aumento da gordura corporal e seu acúmulo na regiãoabdominal aliados a processos infecciosos decorrentes da lesão medular podemacarretar o incremento da concentração plasmática da proteína c-reativa (PCR).Tanto a gordura corporal quanto a elevada concentração da PCR estimulam aprodução de espécies reativas de oxigênio, favorecendo o desequilíbrio oxidativo e odesencadeamento de doenças. É possível que a prática de atividade física regularpossa atuar de modo benéfico através da melhor distribuição da gordura corporal eadaptação dos sistemas antioxidantes nesses indivíduos. Considerando aimportância deste tema e a escassos estudos sobre o assunto, o objetivo desteestudo foi comparar, em indivíduos com lesão medular cervical a composiçãocorporal e indicadores bioquímicos de estado antioxidante em indivíduos fisicamenteativos e não ativos. Participaram do estudo 24 tetraplégicos do gênero masculino(3210 anos de idade e 108 anos de tempo de lesão), divididos em dois grupos,fisicamente ativos (n=15, com pratica de atividade física há pelo menos 3 meses, 3vezes/semana ou mais, totalizando tempo mínimo de 150 minutos/semana) e nãoativos (n=9). A composição corporal foi determinada por absorciometria de duplaemissão de raio-X. Amostras de sangue foram coletadas após jejum de 12 horaspara determinação dos indicadores bioquímicos: de capacidade antioxidante, ácidoúrico, bilirrubina, albumina, alfa-tocoferol, malondialdeído e PCR no plasma eatividade da superóxido dismutase em eritrócitos. O grupo não ativo apresentoumaior IMC (=0,003), gordura total (%) e de tronco (%) (=<0,001) do que o grupoppfisicamente ativo. Foi encontrada relação entre a PCR e a porcentagem de gorduratotal (r=0,72, p=<0,001), de tronco (r=0,70, p=<0,001), massa gorda total (r=0,73,p=<0,001) e de tronco (r=0,67, p=0,001). Não houve diferença significativa entre osindicadores bioquímicos de estado antioxidante, exceto a concentração da PCR quefoi maior no grupo não ativo (p=0,034). Considerando todos indivíduos, 50% apresentavam deficiência de alfa-tocoferol (concentração plasmática <11,6 mol/L).Foi observada relação negativa entre a concentração plasmática de alfa-tocoferol e aPCR (r=-0,18, =0,038).No grupo ativo houve correlação positiva entre a razãoptempo de atividade física:tempo de lesão e concentração plasmática demalondialdeido (r=0,38, =0,014). Nossos resultados, analisados em conjunto,psugerem que prática contínua de atividade física após a lesão atua auxiliando a umamelhor composição corporal e, possivelmente, a uma menor concentraçãoplasmática de PCR. O estado nutricional inadequado em alfa-tocoferol podecomprometer capacidade antioxidante, sendo necessárias medidas de apoionutricional para adequar a ingestão de alfa-tocoferol para este grupo.

Effects of Small-Sided Games vs. Interval Training in Aerobic Fitness and Physical Enjoyment in Young Elite Soccer Players

The purpose of this study was to compare the effects of Small-Sided Games (SSG) vs. Interval Training (IT) in soccer training on aerobic fitness and physical enjoyment in youth elite soccer players during the last 8 weeks of the season. Seventeen U-16 male soccer players (age = 15.5 +/- 0.6 years, and 8.5 years of experience) of a Spanish First Division club academy were randomized to 2 different groups for 6 weeks: SSG group (n = 9) and IT group (n = 8). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 11 sessions with different SSGs, whereas the IT group performed the same number of sessions of IT. Players were tested before and after the 6-week training intervention with a continuous maximal multistage running field test and the counter movement jump test (CMJ). At the end of the study, players answered the physical activity enjoyment scale (PACES). During the study, heart rate (HR) and session perceived effort (sRPE) were assessed. SSGs were as effective as IT in maintaining the aerobic fitness in elite young soccer players during the last weeks of the season. Players in the SSG group declared a greater physical enjoyment than IT (P = 0.006; ES = 1.86 +/- 1.07). Coaches could use SSG training during the last weeks of the season as an option without fear of losing aerobic fitness while promoting high physical enjoyment.

Self-reported sitting time and physical activity: interactive associations with mental well-being and productivity in office employees

Background: Little is known about how sitting time, alone or in combination with markers of physical activity (PA), influences mental well-being and work productivity. Given the need to develop workplace PA interventions that target employees' health related efficiency outcomes; this study examined the associations between self-reported sitting time, PA, mental well-being and work productivity in office employees. Methods: Descriptive cross-sectional study. Spanish university office employees (n = 557) completed a survey measuring socio-demographics, total and domain specific (work and travel) self-reported sitting time, PA (International Physical Activity Questionnaire short version), mental well-being (Warwick-Edinburg Mental Well-Being Scale) and work productivity (Work Limitations Questionnaire). Multivariate linear regression analyses determined associations between the main variables adjusted for gender, age, body mass index and occupation. PA levels (low, moderate and high) were introduced into the model to examine interactive associations. Results: Higher volumes of PA were related to higher mental well-being, work productivity and spending less time sitting at work, throughout the working day and travelling during the week, including the weekends (p < 0.05). Greater levels of sitting during weekends was associated with lower mental well-being (p < 0.05). Similarly, more sitting while travelling at weekends was linked to lower work productivity (p < 0.05). In highly active employees, higher sitting times on work days and occupational sitting were associated with decreased mental well-being (p < 0.05). Higher sitting times while travelling on weekend days was also linked to lower work productivity in the highly active (p < 0.05). No significant associations were observed in low active employees. Conclusions: Employees' PA levels exerts different influences on the associations between sitting time, mental well-being and work productivity. The specific associations and the broad sweep of evidence in the current study suggest that workplace PA strategies to improve the mental well-being and productivity of all employees should focus on reducing sitting time alongside efforts to increase PA.

Number of Players and Relative Pitch Area per Player: Comparing Their Influence on Heart Rate and Physical Demands in Under-12 and Under-13 Football Players

The aim of the present study is to analyse the influence of different large-sided games (LSGs) on the physical and physiological variables in under-12s (U12) and -13s (U13) soccer players. The effects of the combination of different number of players per team, 7, 9, and 11 (P7, P9, and P11, respectively) with three relative pitch areas, 100, 200, and 300 m(2) (A100, A200, and A300, respectively), were analysed in this study. The variables analysed were: 1) global indicator such as total distance (TD); work:rest ratio (W:R); player-load (PL) and maximal speed (V-max); 2) heart rate (HR) mean and time spent in different intensity zones of HR (<75%, 75-84%, 84-90% and >90%), and; 3) five absolute (<8, 8-13, 13-16 and >16 Km h(-1)) and three relative speed categories (<40%, 40-60% and >60% V-max). The results support the theory that a change in format (player number and pitch dimensions) affects no similarly in the two players categories. Although it can seem that U13 players are more demanded in this kind of LSG, when the work load is assessed from a relative point of view, great pitch dimensions and/or high number of player per team are involved in the training task to the U12 players. The results of this study could alert to the coaches to avoid some types of LSGs for the U12 players such as:P11 played in A100, A200 or A300, P9 played in A200 or A300 and P7 played in A300 due to that U13>U12 in several physical and physiological variables (W:R, time spent in 84-90% HRmax, distance in 8-13 and 13-16 Km h(-1) and time spent in 40-60% V-max). These results may help youth soccer coaches to plan the progressive introduction of LSGs so that task demands are adapted to the physiological and physical development of participants.