Drought impact on forest carbon dynamics and fluxes in Amazonia.

In 2005 and 2010 the Amazon basin experienced two strong droughts, driven by shifts in the tropical hydrological regime possibly associated with global climate change, as predicted by some global models. Tree mortality increased after the 2005 drought, and regional atmospheric inversion modelling showed basin-wide decreases in CO2 uptake in 2010 compared with 2011 (ref. 5). But the response of tropical forest carbon cycling to these droughts is not fully understood and there has been no detailed multi-site investigation in situ. Here we use several years of data from a network of thirteen 1-ha forest plots spread throughout South America, where each component of net primary production (NPP), autotrophic respiration and heterotrophic respiration is measured separately, to develop a better mechanistic understanding of the impact of the 2010 drought on the Amazon forest. We find that total NPP remained constant throughout the drought. However, towards the end of the drought, autotrophic respiration, especially in roots and stems, declined significantly compared with measurements in 2009 made in the absence of drought, with extended decreases in autotrophic respiration in the three driest plots. In the year after the drought, total NPP remained constant but the allocation of carbon shifted towards canopy NPP and away from fine-root NPP. Both leaf-level and plot-level measurements indicate that severe drought suppresses photosynthesis. Scaling these measurements to the entire Amazon basin with rainfall data, we estimate that drought suppressed Amazon-wide photosynthesis in 2010 by 0.38 petagrams of carbon (0.23-0.53 petagrams of carbon). Overall, we find that during this drought, instead of reducing total NPP, trees prioritized growth by reducing autotrophic respiration that was unrelated to growth. This suggests that trees decrease investment in tissue maintenance and defence, in line with eco-evolutionary theories that trees are competitively disadvantaged in the absence of growth. We propose that weakened maintenance and defence investment may, in turn, cause the increase in post-drought tree mortality observed at our plots.

Photoprotective and Antimutagenic Activity of Agaricus subrufescens Basidiocarp Extracts.

The photoprotective and antimutagenic activity of opened and closed basidiocarps of Agaricus subrufescens (=A. blazei; =A. brasiliensis) obtained by different extraction methods were evaluated on Aspergillus nidulans conidia submitted to ultraviolet (UV) light. The aqueous extracts were obtained by three extraction methods: maceration, infusion, and decoction, at two different extraction times. The extracts of A. subrufescens did not present toxicity for A. nidulans conidia. A suspension of A. nidulans conidia was submitted to extracts before and after the exposure to UV light. All basidiocarp extracts, regardless of the extraction method or development stage, protected A. nidulans conidia against the damaging effects of the mutagenic agent. The antimutagenic and photoprotective activity was strengthened with extracts obtained by 168-h maceration, followed by 24-h maceration and 60-min infusion and, at last, by 30-min infusion. Although the extracts presented protector effect as well as recoverer effect to the action of UV light, the preventive effect was more evident. Differences in the biological activity in function of the different development stages were detected with greater antimutagenic and photoprotective activity for the opened basidiocarps. However, the extraction method is the most important factor to be considered when compared to the basidiocarp development stage to obtain better antimutagenic and photoprotective activity of A. subrufescens basidiocarps.

Predicting outcomes and complications of percutaneous endoscopic gastrostomy.

BACKGROUND AND STUDY AIMS: Percutaneous endoscopic gastrostomy (PEG) is the preferred route for long-term enteral feeding. Our aims were to prospectively evaluate the outcome ("PEG status") and complications of PEG and to determine whether these can be predicted by patients' baseline characteristics. PATIENTS AND METHODS: We conducted a prospective study in two tertiary hospitals between August 2003 and January 2005, enrolling all patients who were undergoing PEG placement. We completed a questionnaire with details of demographic data, diagnosis, indication for PEG, Charlson's co-morbidity index, Barthel's index, laboratory tests, complications, and date and cause of death. Patients were followed at scheduled appointments. Univariate and multivariate analyses were performed. RESULTS: 168 patients (48% male, 52% female; mean age +/- standard deviation 74 +/- 16 years) underwent PEG using the pull technique. The main indication was neurogenic dysphagia (156 patients, 92.9%). Although most indications were appropriate, in half the cases these were established too late. There were no procedure-related deaths. Major complications occurred in four patients (2.4%); minor complications occurred in 52 patients (31%). No single variable could predict complications. Fifteen patients (9%) had the PEG removed. No single variable was independently associated with PEG removal. The mortality was 6.5% at 30 days, 17.3% at 90 days and 33.9% at 1 year. The C-reactive protein was the only predictive factor of early mortality (< or = 30 days), and Charlson's co-morbidity index was the only predictive factor of late mortality (> 30 days). CONCLUSIONS: PEG placement is an easy and safe procedure, although it is often requested too late. No single variable could predict complications or PEG removal. C-reactive protein was found to be predictive of early mortality and Charlson's index was predictive of late mortality.

[Nurses' perception of management]. / Percepção dos enfermeiros de unidade de internação sobre gerência.

The objective of this investigation is to identify nurses perception about wards management. The collecting of the data was mode through an organized interview with sixteen nurses which works in patients wards in three hospitals of Porto Alegre. The data were examined based on the conteud analysis proposed by Bardin (1977). The results showed five categories: management conception, management characteristics, nurses activities, feelings and nursing graduation and induce us to do some reflexion about the curriculum modification, nurse-teachers improvement and the adjustment between the learning necessity and the work market. In this way is vital that professionals to look for best proficiency.