304 research outputs found
Challenges and perspectives of academic evaluation
A avaliação acadêmica constitui um componente essencial da ciência moderna, na medida em que esta evoluiu do mecenato individualizado para seu papel contemporâneo de pilar das sociedades contemporâneas e democráticas. O Brasil tem experimentado em anos recentes um crescimento consistente de sua produção científica, hoje plenamente compatível com seu status de país de renda média-alta, em vias de se tornar um país desenvolvido e igualitário nos anos por vir. Crescer é lidar com desafios e dilemas, e a avaliação acadêmica não está isenta deles. Em um país de dimensões continentais, profundamente heterogêneo, que conta com sistemas nacionais de avaliação e plataformas eletrônicas de disseminação da informação em diferentes campos do conhecimento, esses desafios se referem à necessidade de estar atento ao detalhe sem perder de vista a abrangência e lidar com a diversidade regional e social, sem abrir mão da excelência acadêmica como marco fundamental.Academic evaluation has been an essential component of modern science since its inception, as science has moved away from personalized patronage toward its contemporary role as an essential enterprise of contemporary, democratic societies. In recent years, Brazil has experienced sustained growth in its scientific output, which is nowadays fully compatible with its status as a high middle-income country striving to become a fully developed, more equitable country in the years to come. Growth usually takes place amidst challenges and dilemmas and, in Brazil as elsewhere, academic evaluation is not exempt from such difficulties. In a large, profoundly heterogeneous country with a national evaluation system and nationwide on-line platforms disseminating information on the most disparate fields of knowledge, the main challenges refer to how to pay attention to detail without losing sight of comprehensiveness and how to handle social and regional diversity while preserving academic excellence as the fundamental benchmark.La evaluación académica constituyó un componente esencial de la ciencia moderna, en la medida en que ésta evolucionó del mecenazgo individualizado para su papel contemporáneo de pilar de las sociedades contemporáneas y democráticas. Brasil ha experimentado en años recientes un crecimiento consistente de su producción científica, hoy plenamente compatible con su estatus de país de renta media-alta, en vías de convertirse en un país desarrollado e igualitario en los años por venir. Crecer es lidiar con desafíos y dilemas, y la evaluación académica no está exenta de ellos. En un país de dimensiones continentales, profundamente heterogéneo, que cuenta con sistemas nacionales de evaluación y plataformas electrónicas de diseminación de la información en diferentes campos del conocimiento, éstos desafíos se refieren a la necesidad de estar más atento al detalle sin perder de vista la amplitud y lidiar con la diversidad regional y social, sin abrir mano de la excelencia académica como marco fundamental
Herbage Characteristics as Affected by the Canopies of Dominant Trees in a Savanna of Southern Mozambique
This study surveyed the species composition, forage yield and forage nitrogen concentration of the herbaceous layer 50, 100 and 200% of the canopy radius from the trunks of many-stemmed false thorn, knob thorn, scented thorn and marula trees in a southern Mozambican savanna. Tree species did not affect herbaceous DM yield or species diversity. Neither direction nor distance from the tree trunk affected DM or specific diversity. Crude protein percentages were 15% higher for legumes and 9% higher for grasses at 50% canopy than at 200% canopy. Grasses under the marulas, the only non-legume tree in the study, had 18% lower CP than the average for the other three tree species. Green panic was the predominant grass species under the canopies while no single grass species predominated outside the canopy where common urochloa, Themeda triandra and Aristida spp. were the most common grasses. Vigna spp. and Stylosanthes fruticosa were evenly distributed whereas Tephrosia spp. was found predominantly outside the canopy
Dynamics in Times of Ionizing Radiation and Rainfalls in Tropical Region of Brazil
Low energy gamma rays and rainfalls were monitored each minute in the region around São José dos Campos, (230:10`S, 450:53`W) in Brazil, from March 7th to June 28th in 2017. In this period, it was possible to see the dynamic process that occurs between the presence of ionizing radiation (gamma rays) of low energy and the variation of rain intensity in (mm) / min in the same region. During this period, 12 major peaks of radiation intensity corresponding to 12 rains of high and low intensities were observed. This positive rainfall / radiation correlation is very noticeable in the tropical region of Brazil, which is certainly due to the presence of the decay of 238U uranium into radium 226Ra and arriving at the 222Rn radon with α emission particles and low energy gamma radiation. Therefore, the rain interferes in the presence of the local exhalation of the radon gas, causing the washing of this gas in the low atmosphere, increasing the intensity of radiation measured momentarily in that location. This work shows this dynamic measured in this interval in the year 2017, where there was rainy and dry weather in the place
From fertilizer to food: tracing nitrogen dynamics in conventional and organic farming systems using 15N natural abundance.
From fertilizer to food: tracing N dynamics in conventional and organic cropping systems using 15N.
Saturnus: Um Simulador Discreto Baseado em Eventos para Sistemas de Arquivos Paralelos
The focus of this work is to study parallel file systems, their elements and present Saturnus, a simulator under development for systems like these. The proposal is to use it to extract data and generate information, focusing on load balancing through the studied environment, showing experiments and possible uses for the tool. (O foco desse trabalho e ́ estudar sistemas de arquivos paralelos, seus elementos e apresentar o Saturnus, um simulador em desenvolvimento para sistemas como esses. A proposta consiste em utilizar o mesmo para extrair dados e gerar informacoes, com foco no balanceamento de carga atrave ́s do ambiente estudado, mostrando experimentos e poss ́ıveis usos para a ferramenta.
Nitrogen and carbon isotope composition of organic Fertilizers.
Synthetic (e.g. urea) and organic fertilizers (e.g. compost) differed markedly in N isotope composition and the greater the difference between organic and synthetic fertilizer the more robust will be the differentiation of crops and vegetable grown under different farming systems. The objective of this study was to compare nitrogen and carbon isotope composition of organic fertilizers and manures available for conventional and organic farming in Brazil. Seven samples of organic fertilizer, two of organo-mineral fertilizers and two of different animal manures were analyzed for nitrogen and carbon isotope composition (15N, 13C). Organic fertilizers and manure samples were enriched in 15N as expected. Using synthetic fertilizers as the primary material of organo-mineral fertilizer can imprint a low 15N value to the final product. Organic fertilizers, organo-mineral fertilizers and manures can have their organic feedstock differentiated using 13C. These are preliminary data of the isotopic composition of organic fertilizer in Brazil. Therefore, a wider survey of fertilizers and an experimental approach for organic- and organo-mineral fertilizer production is needed to elucidate the natural isotope variation of the array of available products
The isotopic composition (d15N, d13C) of agricultural wastes and derived composts.
The aim of this study was to measure variations in the isotopic composition (d13C and d15N) during the composting of different agricultural wastes using bench-scale bioreactors. Four different feedstocks of agricultural wastes (Horse bedding manure + legumes residues; Dairy manure + Jatropha mill cake; Dairy manure + sugarcane residues; Dairy manure) were used for aerobic-thermophilic composting. During composting no significant differences were found between the d13C values of the source material and the compost, except for Dairy manure + sugarcane residues. d15N values increased significantly in composts of Horse bedding manure + legumes residues and Dairy manure + Jatropha mill cake. d15N values of composts may be related to NH3 volatilization during the composting process. Isotopic signatures (d13C, d15N) can be used to differentiate composts from different feedstock sources and d15N values may be a quantitative indicator of NH3 volatilization during composting. Use of bench-scale bioreactors is a promising apparatus to study the dynamics of C and N and stable isotopes signatures during composting, but future adjustments regarding sampling methodology are necessary
Nitrogen loss (NH3, N2O) patterns in bench-scale composting.
Nitrogen (N) losses during composting reduce the value of the end product as a fertilizer. Nitrogen is lost during composting mainly by ammonia (NH3) volatilization in the thermophilic phase. We used three bench-scale aerobic bioreactors with a controlled temperature difference (CDT) system as an experimental approach to investigate the pattern of N losses during composting. N2O peak emission occurred much earlier (7h) than NH3 volatilization (48-60h) during the thermophilic phase (~55°C) of bench-scale composting. The NH3 volatilization peak rate occurred following the greater biological activity (O2 consumed/CO2 evolved) at 40°C which could coincide with greater ammonification, but immobilization of NH4+/NH3 also occurs at this point affecting NH3 volatilization. Differences in temperature curves and accumulated NH3-N were related to the biological activity in each vessel. Therefore, O2 consumed/CO2 evolved measurements must be part of the evaluation of composting in further studies for comparisons of techniques to reduce NH3 volatilizatio
- …