219 research outputs found
Grazing behavior of lactating Murrah buffalo cows supplemented with cupuassu byproduct.
The goal of this work was to evaluate grazing behavior of lactating Murrah buffalo cows supplemented with cupuassu byproduct containing 16.8, 51.4, 8.3, 83.5 and 3.4% of ether extract (EE), neutral detergent fiber (NDF), crude protein (CP), total digestible nutrients (TDN) and nonfibrous carbohydrate (NFC), respectively. Experimental rations were balanced for reaching levels of 22.0 % of crude protein (CP) and 80.1 % of total digestible nutrient (TDN)
Controle do nematóide Aphelenchoides besseyi das sementes de arroz
Six trials were carried out at Lorena and Pindamonhangaba, SP, Brazil, to study the control of the rice nematode Aphelenchoides besseyi Christie 1942, for irrigated conditions. Some chemicals and one thermal treatment were effective in decreasing nematode density; nevertheless, there was no association with yield increases. The cultivars IR 841, IAC 435, IAC 120 and IAC 899 were very tolerant to nematode with yields prominence of IAC 899. Em seis experimentos conduzidos nos municípios de Lorena e Pindamonhangaba, SP, procurou-se verificar o efeito de tratamentos químicos e térmico de sementes sobre o nematóide Aphelenchoides besseyi Christie 1942, em condições de cultivo irrigado. Alguns produtos e o tratamento térmico reduziram o nível populacional do nematóide, porém não houve associação entre os dados de redução e aumento na produção. As cultivares utilizadas, IR 841, IAC 435, IAC 120 e IAC 899, demonstraram elevada tolerância ao nematóide, com destaque de produtividade da IAC 899
Effects of light intensity and temperature on Cylindrospermopsis raciborskii (Cyanobacteria) with straight and coiled trichomes: growth rate and morphology
Cylindrospermopsis raciborskii (Woloszynska) Seenayya et Subba Raju (Ordem Nostocales) is one of the most troublesome bloom-forming species in Brazil. Understanding the population dynamics of the different morphotypes of C. raciborskii (straight and coiled) could assist in the prediction of favourable conditions for the proliferation of this potentially toxin-producing species. The aim of the present study was to assess the effects of two different light intensities and temperatures on the growth rate and morphology of the trichomes of the straight and coiled morphotypes. For such, two non-toxin producing strains of C. raciborskii were used - one with a coiled trichome (ITEP31) and another with a straight trichome (ITEP28). The strains were cultured in BG-11 medium in a climatic chamber under controlled conditions. Two light intensities (30 and 90 mu mol.m(-2).s(-1)) were combined at temperatures of 21 and 31 degrees C and the growth rate and morphological changes were analysed. The morphotypes responded differently to the different temperatures and light intensities. Both strains exhibited faster growth velocities when submitted to higher light intensity and temperature. The lower temperature and higher luminosity hampered the development of both strains. Variations in cellular morphology and an absence of akinetes in both strains were related to the lower temperature (21 C). The coiled morphotype demonstrated considerable phenotype plasticity, changing the morphology of trichome throughout its growth curve. Although molecular analysis does not sustain the separation of the morphotypes as distinct species, their different eco-physiological responses should be considered further knowledge of extreme importance for the population control of these potentially toxic organisms.CNPQ [Proc. 300794/2004-5, 500704/2004-0]FAPESP [Proc. 2004/00939-6, 2007/57509-1
Evaluation of the total photoabsorption cross sections for actinides from photofission data and model calculations
We have calculated the fission probabilities for 237-Np, 233,235,238-U,
232-Th, and nat-Pb following the absorption of photons with energies from 68
MeV to 3.77 GeV using the RELDIS Monte-Carlo code. This code implements the
cascade-evaporation-fission model of intermediate-energy photonuclear
reactions. It includes multiparticle production in photoreactions on
intranuclear nucleons, pre-equilibrium emission, and the statistical decay of
excited residual nuclei via competition of evaporation, fission, and
multifragmentation processes. The calculations show that in the GeV energy
region the fission process is not solely responsible for the entire total
photoabsorption cross section, even for the actinides: ~55-70% for 232-Th,
\~70-80% for 238-U, and ~80-95% for 233-U, 235-U, and 237-Np. This is because
certain residual nuclei that are created by deep photospallation at GeV photon
energies have relatively low fission probabilities. Using the recent
experimental data on photofission cross sections for 237-Np and 233,235,238-U
from the Saskatchewan and Jefferson Laboratories and our calculated fission
probabilities, we infer the total photoabsorption cross sections for these four
nuclei. The resulting cross sections per nucleon agree in shape and in
magnitude with each other. However, disagreement in magnitude with
total-photoabsorption cross-section data from previous measurements for nuclei
from C to Pb calls into question the concept of a ``Universal Curve'' for the
photoabsorption cross section per nucleon for all nuclei.Comment: 39 pages including 11 figure
Mutual heavy ion dissociation in peripheral collisions at ultrarelativistic energies
We study mutual dissociation of heavy nuclei in peripheral collisions at
ultrarelativistic energies. Earlier this process was proposed for beam
luminosity monitoring via simultaneous registration of forward and backward
neutrons in zero degree calorimeters at Relativistic Heavy Ion Collider.
Electromagnetic dissociation of heavy ions is considered in the framework of
the Weizsacker-Williams method and simulated by the RELDIS code. Photoneutron
cross sections measured in different experiments and calculated by the GNASH
code are used as input for the calculations of dissociation cross sections. The
difference in results obtained with different inputs provides a realistic
estimation for the systematic uncertainty of the luminosity monitoring method.
Contribution to simultaneous neutron emission due to grazing nuclear
interactions is calculated within the abrasion model. Good description of CERN
SPS experimental data on Au and Pb dissociation gives confidence in predictive
power of the model for AuAu and PbPb collisions at RHIC and LHC.Comment: 46 pages with 7 tables and 13 figures, numerical integration accuracy
improved, next-to-leading-order corrections include
Neglected area of meiobenthos: bibliometric analysis in the status of research on hyporheic meiofauna.
Studies on freshwater meiofauna are still enigmatic. This field of research is relatively neglected because this topic is not as increasing as the others, creating a gap in this area. The deficit of knowledge and surveys impose a barrier to new research and the increase of scientific interest in this area. This paper briefly reviews what exists in freshwater meiofauna worldwide, focusing on increasing knowledge on this topic and making this little-known area of meiofauna a common study field in science. The methodology involved a bibliographic survey from the Web of Science (WOS) bibliographic database. The search was performed by document title, keywords, and abstract, highlighting meiofauna (or meiobenthos) and hyporheic zone (or hyporheos). The results showed 28 documents on hyporheic meiofauna worldwide, mainly concentrated in Germany. The few articles highlighted that the lack of research on the hyporheic meiofauna community, its ecology, taxonomy, and biology is evident. It is hoped that this bibliometric review can be used as an alert about this area of meiofauna that is so important but at the same time is neglected, having a very exclusive group of authors and works, being of extreme importance different directions of research that involves hyporheic meiofauna to a better understanding of this fauna importance, ecosystemic services, and ecology
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