Portable instrument for in-vivo infrared oxymetry using spread-spectrum modulation

Near Infrared Spectroscopy (NIRS) can be employed to monitor noninvasively and continuously local changes in hemodynamics and oxygenation of human tissues. A portable NIRS research-grade acquisition system, dedicated to measurements during muscular exercise, is presented. The instrument is able to control up to eight LED sources and two detectors. A digital correlation technique, implemented on a single-chip RISC microcontroller, performs source-to-detector multiplexing. Such algorithm is highly optimized for computational efficiency and ambient noise rejection. Software-configurable input stages allow for flexibility in instrument setup. As a result of the specific correlation technique employed, the instrument is compact, lightweight and efficient. Clinical tests on oxygen consumption show excellent performance

Portable instrument for in-vivo infrared oxymetry using spread-spectrum modulation

Near Infrared Spectroscopy (NIRS) can be employed to monitor noninvasively and continuously local changes in hemodynamics and oxygenation of human tissues. A portable NIRS research-grade acquisition system, dedicated to measurements during muscular exercise, is presented. The instrument is able to control up to eight LED sources and two detectors. A digital correlation technique, implemented on a single-chip RISC microcontroller, performs source-to-detector multiplexing. Such algorithm is highly optimized for computational efficiency and ambient noise rejection. Software-configurable input stages allow for flexibility in instrument setup. As a result of the specific correlation technique employed, the instrument is compact, lightweight and efficient. Clinical tests on oxygen consumption show excellent performance

Desempenho de bovinos simulado pelo modelo Pampa Corte e obtido por experimentação Animal performance simulated by Pampa Corte model with experimental records

Este trabalho tem como objetivo verificar a confiabilidade do Modelo Pampa Corte na predição de desempenho de bovinos de corte, em sistemas de pastejo. Para tanto, foram confrontados os valores preditos pelo modelo com dados disponíveis na literatura. Foram verificados coeficientes de correlação acima de 90% entre os dados reais e os simulados em todas as alternativas testadas. O banco de dados do Modelo precisa ser ampliado em termos de alternativas de produtividade das forrageiras, em diferentes condições climáticas. Os parâmetros qualitativos degradabilidade da proteína bruta e fibra em detergente neutro da consorciação aveia preta e azevém necessitam ainda ser pesquisados, assim como o desempenho de animais em pastagens singulares de aveia ou azevém.<br>This study had the objective to evaluate Pampa Corte Model’s reliability in predicting beef cattle performance in grazing systems. For this purpose, model’s predicted values were compared to available data base of published papers. Correlation coefficients above 90 % were obtained between simulated and real data in all tested alternatives. Model’s data base should be enlarged by forage productivity data in different climatic conditions. Mixtures of Italian ryegrass and oat need more studies to obtain qualitative parameters (crude protein degradability and neutral detergent fiber), as well, animal performance in the single pastures of oat or Italian ryegrass

Nutrição mineral, crescimento e teor de óleo essencial da menta em solução nutritiva sob diferentes concentrações de fósforo e épocas de coleta Mineral nutrition, growth and essential oil content of mint in nutrient solution under different phosphorus concentrations

Avaliou-se o efeito de concentrações de P e épocas de coleta sobre o crescimento, nutrição mineral e teor de óleo essencial da menta (Mentha piperita L.). O delineamento experimental foi em blocos casualizados com parcelas subdivididas, em esquema fatorial 2x5, sendo 2 épocas de coleta (65 e 95 dias de cultivo (DC)) e 5 concentrações de P na solução nutritiva (6; 12; 18; 24 e 30 mg L-1), com 4 repetições. Foi determinada a massa seca de folhas (MSF), caules (MSC), raízes (MSR) e total (MST) e as relações folha:caule (F:C) e parte aérea:raiz (PA:R). Também, foi determinado o teor de óleo essencial em folhas frescas. Os níveis críticos foliares e acúmulo de nutrientes na parte aérea da menta foram estimados por meio da análise química das folhas e caules. As concentrações de P na solução influenciaram o crescimento e a produção de óleo essencial pela menta. Na coleta realizada aos 65 DC, apenas a MSF foi influenciada pelo P, não se observando efeito sobre os teores de óleo essencial. Aos 95 DC, o aumento da concentração de P promoveu aumentos significativos na massa seca das partes e do total da menta e, também, nos teores de óleo essencial, sendo o teor máximo (2,192 dag kg-1) obtido com 19,50 mg L-1 de P. As maiores concentrações de P avaliadas (24 e 30 mg L-1), promoveram aumentos na produção de matéria fresca e seca da parte aérea da menta, mas, reduziram os teores de óleo essencial, devido ao efeito de diluição, não significando, portanto, ganhos de produção de óleo por planta. Os teores foliares dos nutrientes associados ao teor máximo de óleo aos 95 DC foram em g kg-1: N=37,2; =3,9; K=21,2; Ca=9,3; Mg=3,8; S=3,0; e, em mg kg-1: B=35; Cu=8; Fe=323; Mn=145 e Zn=22. A exigência nutricional aos 95 DC relacionada ao teor máximo de óleo essencial seguiu a seqüência: N>K>Ca>P>Mg>S>Fe>Mn>B>Zn>Cu.<br>The effect of P concentrations and harvest period upon the growth, mineral nutrition and essential oil content of mint (Mentha piperita L.) was evaluated. The experimental design was of randomized blocks in a split-plot scheme, in a 2x5 factorial with four replications, being two harvest periods (65 and 95 days of cultivation (DC)) and five concentrations of P in the nutrient solution (6; 12; 18; 24 and 30 mg L-1) evaluated. The leaves dry weight (MSF), stems dry weight (MRS), roots dry weight (MSR), total dry weight (MST), leaf:stem ratio (F:C) and aerial part:root ratio (PA:R) were evaluated. The essential oil content in fresh leaves was determined. The critical levels and nutrient accumulation in leaves and stems were estimated through leaves and stems chemical analysis. The level of P increased the leaf dry matter production 65 DC. At 95 DC, the P concentration in the nutrient solution, did significantly increase plant growth and essential oil content, the maximum essential oil content being (2.192 dag kg-1) obtained with 19.48 mg L-1 of P. The higher P concentration in nutrient solution (24 and 30 mg L-1), increased the fresh and dry matter of the aerial portion of the plants, but, decreased the essential oil content. Due to the dilution effect, the increase of fresh and dry matter production did not result in an increase in the oil yield per plant. The critical levels of nutrients in the leaves corresponding to the maximum essential oil content at 95 DC in g kg-1 were: N=37,2; P=3,9; K=21,2; Ca=9,3; Mg=3,8; S=3,0 and, in mg kg-1: B=35; Cu=8; Fe=323; Mn=145 and Zn=22. The nutrients requested at 95 DC related to the maximum essential oil content was: N>K>Ca>P>Mg>S>Fe>Mn>B>Zn>Cu