Demographic bottlenecks in tropical plant regeneration: A comparative analysis of causal influences

Mortality factors that act sequentially through the demographic transitions from seed to sapling may have critical effects on recruitment success. Understanding how habitat heterogeneity influences the causal factors that limit propagule establishment in natural populations is central to assess these demographic bottlenecks and their consequences. Bamboos often influence forest structure and dynamics and are a major factor in generating landscape complexity and habitat heterogeneity in tropical forests. To understand how patch heterogeneity influences plant recruitment we studied critical establishment stages during early recruitment of Euterpe edulis, Sloanea guianensis and Virola bicuhyba in bamboo and non-bamboo stands in the Brazilian Atlantic forest. We combined observational studies of seed rain and seedling emergence with seed addition experiments to evaluate the transition probabilities among regeneration stages within bamboo and non-bamboo stands. The relative importance of each mortality factor was evaluated by determining how the loss of propagules affected stage-specific recruitment success. Our results revealed that the seed addition treatment significantly increased seedling survivorship for all three species. E. edulis seedling survival probability increased in the addition treatment in the two stand types. However, for S. guianensis and V. bicuhyba this effect depended strongly on artificially protecting the seeds, as both species experienced increased seed and seedling losses due to post-dispersal seed predators and herbivores. Propagules of all three species had a greater probability of reaching subsequent recruitment stages when protected. The recruitment of large-seeded V. bicuhyba and E. edulis appears to be much more limited by post-dispersal factors than by dispersal limitation, whereas the small-seeded S. guianensis showed an even stronger effect of post-dispersal factors causing recruitment collapse in some situations. We demonstrated that E. edulis, S. guianensis and V. bicuhyba are especially susceptible to predation during early compared with later establishment stages and this early stage mortality can be more crucial than stand differences as determinants of successful regeneration. Among-species differences in the relative importance of dispersal vs. establishment limitation are mediated by variability in species responses to patch heterogeneity. Thus, bamboo effects on the early recruitment of non-bamboo species are patchy and species-specific, with successional bamboo patches exerting a far-reaching influence on the heterogeneity of plant species composition and abundance. © 2012 Perspectives in Plant Ecology, Evolution and Systematics.

Hydrogen production by biogas steam reforming: A technical, economic and ecological analysis

Fuel cells are electrochemical energy conversion devices that convert fuel and oxidant electrochemically into electrical energy, water and heat. Compared to traditional electricity generation technologies that use combustion processes to convert fuel into heat, and then into mechanical energy, fuel cells convert the hydrogen and oxygen chemical energy into electrical energy, without intermediate conversion processes, and with higher efficiency. In order to make the fuel cells an achievable and useful technology, it is firstly necessary to develop an economic and efficient way for hydrogen production. Molecular hydrogen is always found combined with other chemical compounds in nature, so it must be isolated. In this paper, the technical, economical and ecological aspects of hydrogen production by biogas steam reforming are presented. The economic feasibility calculation was performed to evaluate how interesting the process is by analyzing the investment, operation and maintenance costs of the biogas steam reformer and the hydrogen production cost achieved the value of 0.27 US$/kWh with a payback period of 8 years. An ecological efficiency of 94.95%, which is a good ecological value, was obtained. The results obtained by these analyses showed that this type of hydrogen production is an environmentally attractive route. © 2013 Elsevier Ltd.

Estimação de variáveis físico-químicas de solo por espectroscopia no visível e no infravermelho próximo através de sistemas inteligentes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluación preliminar del impacto en México de la influenza AH1N1: documento elaborado por el equipo conjunto CEPAL

Incluye Bibliografía

Analysis of trade flows between Puerto Rico and CARICOM and prospects for integration

Includes bibliography

Emigration of nurses from the Caribbean: causes and consequences for the socio-economic welfare of the country, Trinidad and Tobago: a case study

Includes bibliography

Traffic congestion: its economic and social consequences

Urban transport in the largest Latin American and Caribbean cities consumes about 3.5% of regional GDP — a percentage that is inflated by the effects of traffic congestion. In addition to the costs of congestion in terms of lost economic efficiency, there are also negative consequences in terms of social cohesion. The phenomenon of traffic congestion, which is caused mainly by relatively wealthy car drivers, lengthens journey times and, more importantly, forces up public transport fares. Owning a car is one of the fruits of human progress; using it in conditions of acute congestion or contamination is a social ill.

Analysis of extreme events in the Caribbean 1990-2008

This study presents an analysis of extreme events in the Caribbean subregion for the period 1990 to 2008, and forms part of a similar, wider study focused on the Latin America and the Caribbean region (Central America and South America being the other two subregional components). It explores the economic costs of climate change through an examination of adaptation costs to extreme events. ECLAC, through its Subregional Headquarters for the Caribbean, is pleased to have been able to undertake this study with the financial support of DFID and to have ensured its successful execution in collaboration with technical expertise from the University of the West Indies.

Preliminary risk analysis applied to the handling of health-care waste

Between 75% and 90% of the waste produced by health-care providers no risk or is "general" health-care waste, comparable to domestic waste. The remaining 10-25% of health-care waste is regarded as hazardous due to one or more of the following characteristics: it may contain infectious agents, sharps, toxic or hazardous chemicals or it may be radioactive. Infectious health-care waste, particularly sharps, has been responsible for most of the accidents reported in the literature. In this work the preliminary risks analysis (PRA) technique was used to evaluate practices in the handling of infectious health-care waste. Currently the PRA technique is being used to identify and to evaluate the potential for hazard of the activities, products, and services from facilities and industries. The system studied was a health-care establishment which has handling practices for infectious waste. Thirty-six procedures related to segregation, containment, internal collection, and storage operation were analyzed. The severity of the consequences of the failure (risk) that can occur from careless management of infectious health-care waste was classified into four categories: negligible, marginal, critical, and catastrophic. The results obtained in this study showed that events with critics consequences, about 80%, may occur during the implementation of the containment operation, suggesting the need to prioritize this operation. As a result of the methodology applied in this work, a flowchart the risk series was also obtained. In the flowchart the events that can occur as a consequence of a improper handling of infectious health-care waste, which can cause critical risks such as injuries from sharps and contamination (infection) from pathogenic microorganisms, are shown.

Enhanced Recovery after Elective Open Surgical Repair of Abdominal Aortic Aneurysm: A Complementary Overview through a Pooled Analysis of Proportions from Case Series Studies

Objectives: To evaluate the efficacy and safety of enhanced recovery after surgery (ERAS) programs in elective open surgical repair (OSR) of abdominal aortic aneurysm (AAA).Background: Open surgical repair of AAA is associated with high morbidity and mortality, prolonged hospital stay and high costs. ERAS programs contribute to the optimization of treatment by reducing hospital stay and improving clinical outcomes.Methods: A review of PubMed, EMBASE and LILACS databases was conducted. As only one randomized controlled trial was found, a pooled analysis of proportions from case series was conducted, considering it a complementary overview of the topic. Inclusion criteria were case series with more than five cases reported, adult patients who underwent an elective OSR of AAA and use of an ERAS program. ERAS was compared to conventional perioperative care. The pooled proportion and the confidence interval (CI) are shown for each outcome. The overlap of the CI suggests similar effect of the interventions studied.Results: Thirteen case series studies with ERAS involving 1,250 patients were compared to six case series with conventional care with a total of 1,429 patients. The pooled, respective proportions for ERAS and conventional care were: mortality, 1.51% [95% CI: 0.0091, 0.0226] and 3.0% [95% CI 0.0183, 0.0445]; and incidence of complications, 3.82% [95% CI 0.0259, 0.0528] and 4.0% [95% CI 0.03, 0.05].Conclusion: This review shows that ERAS and conventional care therapies have similar mortality and complication rates in OSR of AAA.

Thermodynamic and economic analysis of hydrogen production integration in the Brazilian sugar and alcohol industry

One of the biggest challenges today is to develop clean fuels, which do not emit pollutant and with viable implementation. One of the options currently under study is the hydrogen production process. In this context, this work aims to study the technical and economical aspects of the incorporation process of hydrogen producing by ethanol steam reforming in the sugar cane industry and MCFC (molten carbonate fuel cell) application on it to generate electric power. Therefore, it has been proposed a modification in the traditional process of sugar cane industry, in order to incorporate hydrogen production, besides the traditional products (sugar, ethylic, hydrated and anhydric alcohol). For this purpose, a detailed theoretical study of the ethanol production process, describing the considerations to incorporate the hydrogen production will be performed. After that, there will be a thermodynamic study for analysing the innovation of this production chain, as well as a study of economic engineering to allocate the costs of products of the new process, optimising it and considering the thermoeconomics as being as an analysis tool. This proposal aims to improve Brazil's position in the ranking of international biofuels, corroborating the nation to be a power in the hydrogen era. (C) 2013 Elsevier Ltd. All rights reserved.

Linear Versus Geometric Morphometric Approaches for the Analysis of Head Shape Dimorphism in Lizards

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nickel exposure promotes osmoregulatory disturbances in Oreochromis niloticus gills: histopathological and energy dispersive spectrometry analysis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Productivity and costs of Beller-Buncher and forest processor in stands of eucalypts in first cut

The rationalization of forest harvesting and minimization costs is a constant search by the managers involved in this process, making them decide practices which are economically viable to optimize that operation. This study aimed to evaluate technically and economically the performance of feller-buncher and the forest processor in stands of eucalypts in first cut. The technique analysis included time and movements, productivity, efficiency operational and mechanical availability. The economic analysis included the parameters operational cost, harvesting cost and energy consumption. Aiming the optimization the cost of forest harvesting, the system composed by feller-buncher and processor forest presented itself as a technically and economically viable alternative to harvesting eucalypt in first cut or stands that do not have bifurcated trees.

Analise de defeitos em motores através de vibração mecânica: estudo de caso

Revolving machines are among the most used equipment in general industry and therefore expenditures on this equipment class are a significant portion of the total amount spent by the company. If there is an unscheduled stop of some of this equipment, industrial plants can lose huge amounts of money caused by interrupted production and parts delay. Others may increase significantly maintenance costs due to consequences elsewhere not affected before. Even plant and people safety can be in danger if there is an operation interruption without a backup system start. This work is focused on a rotating system case study which is monitored by vibration analysis that shows that is possible to determine when is the most appropriate time for equipment intervention without any reliability loss just by using a simple and cheap system which is not much used because professionals are not aware to its utility. Industrial facilities were evaluated by fail detection and historical analysis in some equipment in order to show feasibility of vibration analysis through a before-during-after process. The plant evaluated is part of a chemical multinational located in Guaratinguetá-SP. At this time, that plant had around 650 critical equipment monthly monitored and no unscheduled shutdown was registered in one year period due to equipment monitoring