Variabilidade diária da precipitação em regiões de floresta e pastagem na Amazônia

As estações automáticas do Projeto ABRACOS instaladas na Amazônia Ocidental forneceram os dados horários de precipitação em áreas de pastagem e floresta, durante o trimestre mais chuvoso (j/f/m) no período de 1992 a 1995. A variabilidade diária de precipitação maior que 1 mm h1 mostrou uma frequência relativa de 6,7% dos casos às 14 horas local (hl) na pastagem e 5,7% às 16 hl na floresta. O período da tarde (13-18 hl) registra acima de 30% dos eventos de precipitação em ambos os sítios. Há uma boa regularidade na distribuição horária dos eventos, principalmente na floresta. Para as precipitações maiores que 10 mm h1, existe uma concentração dos casos no final da tarde. Na pastagem 12,3%, e na floresta 11,5% dos eventos ocorrem às 18 hl. O intervalo entre 7-18 hl detém 64,9% dos casos na pastagem, e 57,7% na floresta. Do total de eventos de precipitação, 14% são maiores que 10 mm h1, tanto na floresta como na pastagem. Comparando-se o total de chuva ocorrido nas áreas de floresta e pastagem, o volume precipitado na floresta é cerca de 28% em média superior ao da pastagem.

Determinação de nimesulida por análise por injeção em fluxo com detecção amperométrica de múltiplos pulsos

A simple and fast method for the determination of nimesulide (NI) using flow injection analysis with multiple-pulse amperometric (FIA-MPA) detection at a boron-doped diamond (BDD) electrode was developed. The method was based mainly on the application of a four-potential waveform, E1(det) = -0.8 V / 30 ms, E2(det) = 0.6 V / 30 ms, E3(det) = -0.4 V / 30 ms and E4(cleaning) = -0.45 V / 300 ms versus Ag/AgCl (3.0 mol L-1 KCl). NI was detected at three different electrode potentials, at which the nitro group undergoes different redox reactions. The proposed method was selective and sensitive (detection limit of 81.0 nmol L-1), and successfully applied for the determination of NI in pharmaceutical formulations, yielding similar results to those obtained by the reference method.

Exercise training and detraining modify the morphological and mechanical properties of single cardiac myocytes obtained from spontaneously hypertensive rats

We determined the effects of exercise training and detraining on the morphological and mechanical properties of left ventricular myocytes in 4-month-old spontaneously hypertensive rats (SHR) randomly divided into the following groups: sedentary for 8 weeks (SED-8), sedentary for 12 weeks (SED-12), treadmill-running trained for 8 weeks (TRA, 16 m/min, 60 min/day, 5 days/week), and treadmill-running trained for 8 weeks followed by 4 weeks of detraining (DET). At sacrifice, left ventricular myocytes were isolated enzymatically, and resting cell length, width, and cell shortening after stimulation at a frequency of 1 Hz (~25°C) were measured. Cell length was greater in TRA than in SED-8 (161.30 ± 1.01 vs 156.10 ± 1.02 μm, P < 0.05, 667 vs 618 cells, respectively) and remained larger after detraining. Cell width and volume were unaffected by either exercise training or detraining. Cell length to width ratio was higher in TRA than in SED-8 (8.50 ± 0.08 vs 8.22 ± 0.10, P < 0.05) and was maintained after detraining. Exercise training did not affect cell shortening, which was unchanged with detraining. TRA cells exhibited higher maximum velocity of shortening than SED-8 (102.01 ± 4.50 vs 82.01 ± 5.30 μm/s, P < 0.05, 70 cells per group), with almost complete regression after detraining. The maximum velocity of relengthening was higher in TRA cells than in SED-8 (88.20 ± 4.01 vs70.01 ± 4.80 μm/s, P < 0.05), returning to sedentary values with detraining. Therefore, exercise training affected left ventricle remodeling in SHR towards eccentric hypertrophy, which remained after detraining. It also improved single left ventricular myocyte contractile function, which was reversed by detraining.