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Amazonian floodplain forests are particularly vulnerable to wildfires that spread during extreme droughts, causing large scale forest dieback. After a second wildfire, these forests persist trapped with low tree cover and empty seed banks, yet the mechanisms that could explain this arrested succession remain unknown. Here we use a four-year field experiment to test whether tree recruitment failures in burnt floodplain forests are caused by environmental filtering, limiting early seedling emergence and establishment. We sowed seeds and planted seedlings of six floodplain trees with contrasting life strategies, and tested the roles of environmental filters by comparing tree seedling performances under different habitats (i.e. unburned forest, forest edge with burnt site, forest burnt once and forest burnt twice), and by manipulating soil root mats and herbaceous cover. Our results show that seedling emergence was around 15 % across all habitats. In general, seedlings performed best in burnt forests. Seedling growth was highest in forests burnt once, possibly because of high nutrient availability after fire. In forests burnt twice, tree seedlings grew relatively less, as nutrients become limiting due to flood erosion; yet, seedlings survived longer, possibly because of lower competition with sparse, naturally recruiting trees. We found similar patterns for seedlings that emerged in the field from sowed seeds. Synthesis: Our experimental evidence suggests that environmental filtering related to soil nutrient limitations may slow down forest recovery after repeated wildfires. Yet, our findings showing that floodplain trees are able to germinate from seeds and establish successfully in twice burnt forests suggest that seed limitation may be the reason why forest recovery fails persistently. A corollary to the problem is that repeatedly burnt forests seem to be trapped by a self-reinforcing feedback, in which low tree cover reduces seed dispersal and consequently seed availability, keeping tree cover low. Overall, our findings indicate that active restoration initiatives based on seeding native tree species may help accelerating the recovery of degraded floodplain forests after repeated wildfires.

Background and purpose:The contribution of endothelin‐1 (ET‐1) to vascular hyper‐reactivity associated with chronic ethanol intake, a major risk factor in several cardiovascular diseases, remains to be investigated.Experimental approach:The biphasic haemodynamic responses to ET‐1 (0.01–0.1 nmol kg−1, i.v.) or to the selective ETB agonist, IRL1620 (0.001–1.0 nmol kg−1, i.v.), with or without ETA or ETB antagonists (BQ123 (c(DTrp‐Dasp‐Pro‐Dval‐Leu)) at 1 and 2.5 mg kg−1 and BQ788 (N‐cis‐2,6‐dimethyl‐piperidinocarbonyl‐L‐γ‐methylleucyl1‐D‐1methoxycarbonyltryptophanyl‐D‐norleucine) at 0.25 mg kg−1, respectively) were tested in anaesthetized rats, after 2 weeks' chronic ethanol treatment. Hepatic parameters and ET receptor protein levels were also determined.Key results:The initial hypotensive responses to ET‐1 or IRL1620 were unaffected by chronic ethanol intake, whereas the subsequent pressor effects induced by ET‐1, but not by IRL1620, were potentiated. BQ123 at 2.5 but not 1 mg kg−1 reduced the pressor responses to ET‐1 in ethanol‐treated rats. Conversely, BQ788 (0.25 mg kg−1) potentiated ET‐1‐induced increases in mean arterial blood pressure in control as well as in ethanol‐treated rats. Interestingly, in the latter group, increases in heart rate, induced by ET‐1 at a dose of 0.025 mg kg−1 were enhanced following ETB receptor blockade. Finally, we observed higher levels of ETA receptor in the heart and mesenteric artery and a reduction of ETB receptor protein levels in the aorta and kidney from rats chronically treated with ethanol.Conclusions and implications:Increased vascular reactivity to ET‐1 and altered protein levels of ETA and ETB receptors could play a role in the pathogenesis of cardiovascular complications associated with chronic ethanol consumption.British Journal of Pharmacology (2008) 154, 971–981; doi:10.1038/bjp.2008.157; published online 12 May 2008

In response to the intensification of eco-friendly routes as a strategy to access compounds of interest, extraction based on hydrothermal technologies is an efficient method to obtain high yields of compounds present in lignocellulosic materials. Accordingly, this study investigated the effects of the combination of ultrasonic pretreatments (energy density, 1.23 × 103-37.6 × 103 J/cm3; reaction time, 15 and 60 min) and subcritical water hydrolysis (SWH) (temperature, 220°C; flow rate, 10-30 mL/min; and reaction time, 0.5-15 min) on sugar yield profile from residual biomass of rice, soybean, and pecan. A characterization of the sugars present in the hydrolyzed solutions by high-performance liquid chromatography (HPLC) and a physicochemical evaluation of biomasses by Fourier-transform infrared spectroscopy (FT-IR) was performed. The highest yield reported were 23.8/100 g biomass, 14.4/100 g biomass, and 6.0/100 g biomass for pecan shell, rice shell, and soybean straw, respectively. Cellobiose, glucose, xylose, and arabinose were quantified by the HPLC, as well as inhibitors and organic acids. FT-IR indicated the compositions of the fresh and pretreated samples. Appropriately, the combined application of ultrasonic and SWH methods supported the valorization and optimization of high potential materials generated in agricultural processing.

The aim of this study was to evaluate the behavior of an anaerobic reactor of packed-bed and continuous flow, in relation to the biogas and methane production and the removal of organic load, from the wastewater of cassava starch extraction.For this purpose, were tested, in a reactor with a useful volume of 2.82 L and support mean of polypropylene filled with polyethylene foam, the organic loading rate (OLR) of 2.5, 5.0, 8.0 and 10.0 g L -1 d -1 .It was evaluated the removal of COD, the pH, the VA/TA ratio, the biogas and the methane production.It was concluded from this study that it is possible to produce biogas with methane percentages higher than 80% (maximum) and remove the organic load more than 90% under the tested conditions.In relation to stability, the reactor can be considered stable for the parameters, pH, the relationship between volatile acidity and total alkalinity and organic load removal.The best results in relation to the average volumetric biogas production (0.174 and 0.311 L g COD -1 ) were obtained for the higher organic loading rate (of 8 and 10 g L -1 d -1 , respectively) and the observed tendency is that with the increase of the organic loading rate, the specific biogas production will increase as well as the specific production of methane. The aim of this study was to evaluate the behavior of an anaerobic reactor of packed-bed and continuous flow, in relation to the biogas and methane production and the removal of organic load, from the wastewater of cassava starch extraction.For this purpose, were tested, in a reactor with a useful volume of 2.82 L and support mean of polypropylene filled with polyethylene foam, the organic loading rate (OLR) of 2.5, 5.0, 8.0 and 10.0 g L -1 d -1 .It was evaluated the removal of COD, the pH, the VA/TA ratio, the biogas and the methane production.It was concluded from this study that it is possible to produce biogas with methane percentages higher than 80% (maximum) and remove the organic load more than 90% under the tested conditions.In relation to stability, the reactor can be considered stable for the parameters, pH, the relationship between volatile acidity and total alkalinity and organic load removal.The best results in relation to the average volumetric biogas production (0.174 and 0.311 L g COD -1 ) were obtained for the higher organic loading rate (of 8 and 10 g L -1 d -1 , respectively) and the observed tendency is that with the increase of the organic loading rate, the specific biogas production will increase as well as the specific production of methane. The aim of this study was to evaluate the behavior of anaerobic reactor of packed-bed and continuous flow, in relation to the biogas and methane production and the removal of organic load, from the wastewater of cassava starch extraction.For this purpose, were tested, in a reactor with a useful volume of 2.82 L and support mean of polypropylene filled with polyethylene foam, the organic loading rate (OLR) of 2.5, 5.0, 8.0 and 10.0 g L -1 d -1 .It was evaluated the removal of COD, the pH, the VA/TA ratio, the biogas and the methane production.It was concluded from this study that it is possible to produce biogas with methane percentages higher than 80% (maximum) and remove the organic load more than 90% under the tested conditions.In relation to stability, the reactor can be considered stable for the parameters, pH, the relationship between volatile acidity and total alkalinity and organic load removal.The best results in relation to the average volumetric biogas production (0.174 and 0.311 L g COD -1 ) were obtained for the higher organic loading rate (of 8 and 10 g L -1 d -1 , respectively) and the observed tendency is that with the increase of the organic loading rate, the specific biogas production will increase as well as the specific production of methane. The aim of this study was to evaluate the behavior of anaerobic reactor of packed-bed and continuous flow, in relation to the biogas and methane production and the removal of organic load, from the wastewater of cassava starch extraction.For this purpose, were tested, in a reactor with a useful volume of 2.82 L and support mean of polypropylene filled with polyethylene foam, the organic loading rate (OLR) of 2.5, 5.0, 8.0 and 10.0 g L -1 d -1 .It was evaluated the removal of COD, the pH, the VA/TA ratio, the biogas and the methane production.It was concluded from this study that it is possible to produce biogas with methane percentages higher than 80% (maximum) and remove the organic load more than 90% under the tested conditions.In relation to stability, the reactor can be considered stable for the parameters, pH, the relationship between volatile acidity and total alkalinity and organic load removal.The best results in relation to the average volumetric biogas production (0.174 and 0.311 L g COD -1 ) et la tendance observée est que, avec l'augmentation du taux de charge organique, la production spécifique de biogaz augmentera comme la production spécifique de méthane. كان الهدف من هذه الدراسة هو تقييم سلوك مفاعل لاهوائي ذو سرير معبأ وتدفق مستمر، فيما يتعلق بإنتاج الغاز الحيوي والميثان وإزالة الحمل العضوي، من مياه الصرف الصحي لاستخراج نشا المنيهوت. لهذا الغرض، تم اختباره، في مفاعل بحجم مفيد 2.82 لتر ومتوسط دعم من البولي بروبلين المملوء برغوة البولي إيثيلين، معدل التحميل العضوي (OLR) 2.5 و 5.0 و 8.0 و 10.0 جم L -1 d -1. تم تقييم إزالة COD، الأس الهيدروجيني ونسبة VA/TA والغاز الحيوي وإنتاج الميثان. استنتج من هذه الدراسة أنه من الممكن إنتاج الغاز الحيوي بنسب ميثان أعلى من 80 ٪ (كحد أقصى) وإزالة الحمل العضوي أكثر من 90 ٪ في ظل الظروف المختبرة. فيما يتعلق بالاستقرار، يمكن اعتبار المفاعل مستقرًا للمعلمات، الأس الهيدروجيني، العلاقة بين الحموضة المتطايرة والقلوية الكلية وإزالة الحمل العضوي. أفضل النتائج فيما يتعلق بمتوسط إنتاج الغاز الحيوي الحجمي (0.174 و 0.311 لتر من COD -1 ) لمعدل التحميل العضوي الأعلى (8 و 10 جم L -1 d -1 ، على التوالي) والميل الملحوظ هو أنه مع زيادة معدل التحميل العضوي، سيزداد إنتاج الغاز الحيوي المحدد بالإضافة إلى الإنتاج المحدد للميثان.

The design of energy systems usually requires technical, economical and environmental analysis. However, the growth of systems failure due to unpredictable low-probability external events makes the consideration of resilience in this design also important. Although there is no standard metric for resilience quantification yet, it is known that it should consider system configuration, operation time and total or partial energy generation during and after the event, as well as the components repair probability and time. A proposal for resilience quantification in four cogeneration plants was previously developed based on components stochastic failures and verification of their consequences in the plant energy generation. The present work aims to continue the development of this metric by including in its calculation the repair probability of the components, their repairing time and the plant downtime during the repair, essential parameters for resilience quantification. Two new metrics are proposed and simulations with 0, 50% and 75% of repair probability of the components are made in software CLIPS. One of the metrics is able to evaluate the influence of repairment in system resilience, while the other one predicts plant downtime during operation. The metrics point to S#2 as the most resilient system and S#3 as the most affect by repairing.

Abstract The energy consumption of spouted bed is an important issue that has been studied from various aspects. In order to investigate the energy consumption of the equipment, several experiments of drying of sorghum bicolor [Sorghum bicolor (L) Moench] were conducted and the results were evaluated looking for the energy performance of the spouted bed. A methodology that takes into account the mechanical energy necessary to maintain the spout regime on the global energy efficiency was proposed and the performance was determined based on the drying efficiency, energy efficiency, and specific energy consumption with and without the term corresponding to the mechanical contribution. This methodology permits a more rigorous evaluation of the energy performance of drying equipment. The percentage increase of the specific energy consumption due to inclusion of the mechanical energy was greater at higher loads and at lower temperatures, demonstrating that this term represented a significant portion of the energy consumption of the process.

This paper examines potential changes in solid waste policies for the reduction in GHG for the country of Brazil and one of its major states and cities, Rio de Janeiro, from 2005 to 2030. To examine these policy options, trends in solid waste quantities and associated GHG emissions are derived. Three alternative policy scenarios are evaluated in terms of effectiveness, technology, and economics and conclusions posited regarding optimal strategies for Brazil to implement. These scenarios are been building on the guidelines for national inventories of GHG emissions (IPCC, 2006) and adapted to Brazilian states and municipalities' boundaries. Based on the results, it is possible to say that the potential revenue from products of solid waste management is more than sufficient to transform the current scenario in this country into one of financial and environmental gains, where the negative impacts of climate change have created a huge opportunity to expand infrastructure for waste management.

With the recent advancements in power electronics for wind turbines (WTs) and increasing penetration of wind energy, wind power plants (WPP) have become necessary contributors of reactive power support for the bulk power system. Balancing reactive power support with individual WT operating requirements in a cost-effective manner is a challenge for WPP designers. In this paper, we present a methodology to optimize the WPP reactive power capability as seen from the point of common coupling (PCC), accounting for steady-state operating capabilities of the WPP equipment. Thus, the proposed methodology determines the configuration of the tap-changing transformers within the WPP that maximizes the amount of reactive power the WPP can either consume or inject to the network, considering uncertain levels of wind power generation and voltage magnitudes at the PCC. The optimized reactive power capability (ORPC) problem is initially formulated as a mixed-integer nonlinear programming (MINLP) model. Then, a set of efficient linearization techniques are used to obtain a mixed-integer linear programming (MILP) model that can be solved via off-the-shelf mathematical programming solvers. Results demonstrate that the proposed MILP model is a scalable, flexible and accurate method to maximize the reactive power capability of WPP.