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A B S T R A C T Aerosol particles associated with biomass burning emissions affect the surface radiative budget and net ecosystem exchange (NEE) over large areas in Amazonia during the dry season. We analysed CO 2 fluxes as a function of aerosol loading for two forest sites in Amazonia as part of the LBA experiment. Aerosol optical thickness (AOT) measurements were made with AERONET sun photometers, and CO 2 flux measurements were determined by eddy-correlation.The enhancement of the NEE varied with different aerosol loading, as well as cloud cover, solar elevation angles and other parameters. The AOT value with the strongest effect on the NEE in the FLONA-Tapajós site was 1.7, with an enhancement of the NEE of 11% compared with clear-sky conditions. In the RBJ site, the strongest effect was for AOT of 1.6 with an enhancement of 18% in the NEE. For values of AOT lager than 2.7, strong reduction on the NEE was observed due to the reduction in the total solar radiation. The enhancement in the NEE is attributed to the increase of diffuse versus direct solar radiation. Due to the fact that aerosols from biomass burning are present in most tropical areas, its effects on the global carbon budget could also be significant.

SummaryBackground: National studies on decompensated heart failure (DHF) are key to the understanding of this condition in our midst.

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Pulmonary hypertension represents an important cause of morbidity and mortality in patients with mitral stenosis who undergo cardiac surgery, especially in the postoperative period. The aim of this study was to test the hypothesis that inhaled nitric oxide (iNO) would improve the hemodynamic effects and short-term clinical outcomes of patients with mitral stenosis and severe pulmonary hypertension who undergo cardiac surgery in a randomized, controlled study. Twenty-nine patients (4 men, 25 women; mean age 46 ± 2 years) were randomly allocated to receive iNO (n = 14) or oxygen (n = 15) for 48 hours immediately after surgery. Hemodynamic data, the use of vasoactive drugs, duration of stay, and short-term complications were assessed. No differences in baseline characteristics were observed between the groups. After 24 and 48 hours, patients receiving iNO had a significantly greater increase in cardiac index compared to patients receiving oxygen (p <0.0001). Pulmonary vascular resistance was also more significantly reduced in patients receiving iNO versus oxygen (-117 dyne/s/cm(5), 95% confidence interval -34 to -200, vs 40 dyne/s/cm(5), 95% confidence interval -34 to 100, p = 0.005) at 48 hours. Patients in the iNO group used fewer systemic vasoactive drugs (mean 2.1 ± 0.14 vs 2.6 ± 0.16, p = 0.046) and had a shorter intensive care unit stay (median 2 days, interquartile range 0.25, vs median 3 days, interquartile range 7, p = 0.02). In conclusion, iNO immediately after surgery in patients with mitral stenosis and severe pulmonary hypertension improves hemodynamics and may have short-term clinical benefits.