Hypertension is associated with greater heat exchange during exercise recovery in a hot environment

Individuals with systemic arterial hypertension have a higher risk of heat-related complications. Thus, the aim of this study was to examine the thermoregulatory responses of hypertensive subjects during recovery from moderate-intensity exercise performed in the heat. A total of eight essential hypertensive (H) and eight normotensive (N) male subjects (age=46.5±1.3 and 45.6±1.4 years, body mass index=25.8±0.8 and 25.6±0.6 kg/m2, mean arterial pressure=98.0±2.8 and 86.0±2.3 mmHg, respectively) rested for 30 min, performed 1 h of treadmill exercise at 50% of maximal oxygen consumption, and rested for 1 h after exercise in an environmental chamber at 38°C and 60% relative humidity. Skin and core temperatures were measured to calculate heat exchange parameters. Mean arterial pressure was higher in the hypertensive than in the normotensive subjects throughout the experiment (P<0.05, unpaired t-test). The hypertensive subjects stored less heat (H=-24.23±3.99 W·m−2vs N=-13.63±2.24 W·m−2, P=0.03, unpaired t-test), experienced greater variations in body temperature (H=-0.62±0.05°C vsN=-0.35±0.12°C, P=0.03, unpaired t-test), and had more evaporated sweat (H=-106.1±4.59 W·m−2vs N=-91.15±3.24 W·m−2, P=0.01, unpaired t-test) than the normotensive subjects during the period of recovery from exercise. In conclusion, essential hypertensive subjects showed greater sweat evaporation and increased heat dissipation and body cooling relative to normotensive subjects during recovery from moderate-intensity exercise performed in hot conditions

Accuracy of Techniques for Predicting Gas Production by Ruminants Associated with Diet

The aim of this study was to compare the gas production profiles and nutrient degradability of two diets using automatic and semiautomatic in vitro gas production techniques. A randomized block design in a 2 × 2 factorial arrangement was adopted, with two diets comprising different proportions of nonfiber carbohydrates (NFCs) (low-NFC vs. high-NFC diets), two gas production measurement techniques (automatic vs. semiautomatic) and four replicates. The blocks represent three in vitro runs. Gas production from the fermentation of fiber carbohydrates (Vf2) was 22% higher when measured with the automatic technique than with the semiautomatic technique. The Vt of the low-NFC diet differed between techniques and was 22.9% higher using the automatic technique. A highly positive correlation (r = 0.96) was observed between the techniques, with a high coefficient of determination between the techniques (R2 = 0.93). There was greater degradability of dry matter (DMD) and organic matter (OMD) with the automatic technique. In both diets, the degradability of crude protein (CPD) was greater with the semiautomatic technique (p 3-N in the incubation medium than in that of the low-NFC diet, whereas the degradability of DM, OM and CP increased. The automatic and semi-automatic techniques similarly estimated the kinetic parameters and the profiles of total gas production, demonstrating the potential of both techniques for assessing the nutritional value of diets with different proportions of NFCs

The Brazilian time and frequency atomic standards program

Cesium atomic beam clocks have been the workhorse for many demanding applications in science and technology for the past four decades. Tests of the fundamental laws of physics and the search for minute changes in fundamental constants, the synchronization of telecommunication networks, and realization of the satellite-based global positioning system would not be possible without atomic clocks. The adoption of optical cooling and trapping techniques, has produced a major advance in atomic clock precision. Cold-atom fountain and compact cold-atom clocks have also been developed. Measurement precision of a few parts in 10(15) has been demonstrated for a cold-atom fountain clock. We present here an overview of the time and frequency metrology program based on cesium atoms under development at USP São Carlos. This activity consists of construction and characterization of atomic-beam, and several variations of cold-atom clocks. We discuss the basic working principles, construction, evaluation, and important applications of atomic clocks in the Brazilian program.<br>Relógios atômicos de feixe de Césio têm sido a base para diversas aplicações em ciência e tecnologia nas últimas quatro décadas. Testes de leis fundamentais de física, buscas por mínimas variações em constantes fundamentais, sincronização de redes de telecomunicações e o funcionamento do sistema de posicionamento global, baseado em satélites de navegação, não seriam possíveis sem os relógios atômicos. A adoção de técnicas de aprisionamento e resfriamento ópticos tem permitido um grande avanço na precisão dos relógios atômicos. Chafarizes de átomos frios e relógios compactos de átomos frios também têm sido desenvolvidos. Precisões de medida de algumas partes em 1015 foram demonstradas para relógios do tipo chafariz de átomos frios. Apresentamos uma visão geral do programa de metrologia de tempo e freqüência baseado em átomos de césio, em desenvolvimento na USP de São Carlos. Estas atividades consistem na construção e caracterização de relógios do tipo feixe atômico e de outros, utilizando átomos frios. Discutimos os princípios básicos, construção, avaliação e importantes aplicações de relógios atômicos no programa brasileiro

Altura de planta e acúmulo de matéria seca do feijoeiro cvs. BRS MG Talismã e Ouro Negro em plantio direto e convencional Plant height and dry matter acumulation by common bean cvs. BRS MG Talismã and Ouro Negro under no-tillage and conventional crop systems

Com o objetivo de estudar a curva de crescimento em altura de planta, taxa e acúmulo de matéria seca da parte aérea ao longo do ciclo cultural do feijoeiro (Phaseolus vulgaris L.) foram conduzidos quatro experimentos de campo, com as cvs. Ouro Negro e BRS MG Talismã, em plantio direto e convencional, sendo um em Lavras (Latossolo Vermelho distroférrico típico, inverno primavera 2002) e os demais em Madre de Deus de Minas (Latossolo Vermelho Amarelo ácrico, seca 2005). O delineamento experimental foi feito com blocos casualizados com três repetições e 11 ou 12 tratamentos (épocas de coleta). De 7 em 7 dias foram amostradas 10 ou 20 plantas para determinação da altura, através do comprimento da haste principal, e outras 20 plantas para determinação do peso da matéria seca da parte aérea após secagem em estufa com circulação de ar a 65-70ºC até peso constante. Os dados foram submetidos a análises de variância e regressão, com ajuste de curvas representativas do comportamento das características avaliadas. Em plantio direto, a altura máxima foi alcançada aos 50 DAE, enquanto no plantio convencional o feijoeiro continuou crescendo até os 72-73 DAE, ocorrendo fechamento mais tardio da lavoura. As cvs. Ouro Negro e BRS MG Talismã mostraram padrões de acúmulo de matéria seca muito próximos, com pouco incremento até os 81 DAE, na BRS MG Talismã, e ambas alcançaram maiores acúmulos em plantio direto. Em geral, as maiores taxas de acúmulo de matéria seca foram verificadas entre 45-48 DAE.<br>The aim of this research was to study the plant growth in height and the dry matter accumulation pattern along the bean (Phaseolus vulgaris L.) crop cycle. Four field experiments were carried out in Lavras (winter-spring 2002) and other were performed in Madre de Deus de Minas, MG (dry crop season 2005) with common bean, cvs. Ouro Negro and BRS MG Talismã, under no-tillage and conventional crop systems. Every seven days 10 or 20 plants were sampled to height measurements and other 20 plants for dry matter evaluation. The experiments were carried out in randomized block outlines with three replications and 11 or 12 treatments (sampling times). The data were treated with a variance and regression analysis and representative curves of the evaluated variables were fitted and adjusted. The growth curves had showed that the maximum height was reached by the 50 DAE in no-tillage crop system while in the conventional crop system the bean kept on growing up to the 72-73 DAE, closing further in field. The pattern of dry matter accumulation showed that there was a small increment until the 21-24 DAE for the two cultivars. The maximum accumulation could be observed in the no-tillage croping systems by the 75-76 DAE for the cv. Ouro Negro and by the 80-81 DAE for the cv. BES MG Talismã. In general, the highest rates of dry matter accumulation were verified by the 45-48 DAE