Influence of nutrition on the glucose absorption and tolerance test in horses submitted to different fasting periods

Four groups of horses of Brasileiro de Hipismo bred were submitted to fasting for 24 and 48 hours in order to study the absorption capacity of the small intestine. Two groups were fed with coast cross grass (Cynodon dactylon) and the other two groups with coast cross pasture and grains. At the end of the fasting periods, the groups received 1g of glucose/kg of body weight in a 20% solution through a nasogastric tube. Blood samples were collected immediately before and 70, 60, 120, 180, 240, 300, and 360 minutes after glucose administration. Glycemia was determined by the orthotoluidine method and insulin by radioimmunoassay. The animals which received grains showed larger increase in glycemia and insulinemia than those maintained on pasture regimen alone. The 48-hour fasting period induced higher glycemia and insulinemia levels than those observed after 24-hour fasting.

Power-law distribution in a learning process: competition, learning and natural selection

In the present work, we propose a model for the statistical distribution of people versus number of steps acquired by them in a learning process, based on competition, learning and natural selection. We consider that learning ability is normally distributed. We found that the number of people versus step acquired by them in a learning process is given through a power law. As competition, learning and selection is also at the core of all economical and social systems, we consider that power-law scaling is a quantitative description of this process in social systems. This gives an alternative thinking in holistic properties of complex systems. (C) 2004 Elsevier B.V. All rights reserved.

Competition between anchoring and reversible photo-induced alignment of a nematic liquid crystal

We investigated the alignment induced on a nematic liquid crystal (LC) by a photo-aligned polymer film with azo-dye side groups. The orientation of the LC molecules can be manipulated in a reversible manner by irradiating the film with polarized light. We analyzed the competition between the orientation induced by the main chain, through rubbing of the film and that induced by the photo-aligned polymer. Anchoring strength for the different processing conditions are reported. The changes in film morphology caused by rubbing or photo-alignment could be captured by atomic force microscopy. The reversibility of the photo-induced alignment and the competition between the two anchoring mechanisms may allow recording and erasing of information in a LC display.

Serum and plasma hormonal concentrations are sensitive to periods of intensity and volume of soccer training

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Distribution of Neohelice granulata (Dana 1851) in its northernmost latitudinal occurrence in a tropical mangrove forest, Brazil (Crustacea, Decapoda, Brachyura, Grapsoidea, Varunidae).

Neohelice granulata ecological distribution was evaluated in its northernmost latitudinal occurrence in a Brazilian tropical mangrove (23[degree]13'4" S, 44[degree]42'47" W). Samples were collected in three sites along the main river in the mangrove. Crabs were manually captured by two people, 15 min each, at low tide periods. The sex of the animals was assessed and carapace width measured. The size-frequency distribution was determined in each site. Environmental factors (salinity, temperature, organic matter and sediment texture) were analyzed, compared among sites and related to crab abundance and size in each site. Crab abundance decreased with the distance from the sea. Juvenile crabs were more frequent next to the sea, whereas larger and ovigerous ones were mainly found in the most distant site. Crab size was proportional to the organic matter percentage in the sediment. N. granulata spatial distribution varies along the river course, which is probably related to the most productive areas that have more nutrients available; this may also occur in order to prevent intraspecific competition.

Particle Competition and Cooperation in Networks for Semi-Supervised Learning with Concept Drift

Concept drift is a problem of increasing importance in machine learning and data mining. Data sets under analysis are no longer only static databases, but also data streams in which concepts and data distributions may not be stable over time. However, most learning algorithms produced so far are based on the assumption that data comes from a fixed distribution, so they are not suitable to handle concept drifts. Moreover, some concept drifts applications requires fast response, which means an algorithm must always be (re) trained with the latest available data. But the process of labeling data is usually expensive and/or time consuming when compared to unlabeled data acquisition, thus only a small fraction of the incoming data may be effectively labeled. Semi-supervised learning methods may help in this scenario, as they use both labeled and unlabeled data in the training process. However, most of them are also based on the assumption that the data is static. Therefore, semi-supervised learning with concept drifts is still an open challenge in machine learning. Recently, a particle competition and cooperation approach was used to realize graph-based semi-supervised learning from static data. In this paper, we extend that approach to handle data streams and concept drift. The result is a passive algorithm using a single classifier, which naturally adapts to concept changes, without any explicit drift detection mechanism. Its built-in mechanisms provide a natural way of learning from new data, gradually forgetting older knowledge as older labeled data items became less influent on the classification of newer data items. Some computer simulation are presented, showing the effectiveness of the proposed method.

Horizontal distribution of megalopae of Brachyura (Crustacea, Decapoda) in a South American tropical estuary

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

On the number of critical periods for planar polynomial systems

In this paper we get some lower bounds for the number of critical periods of families of centers which are perturbations of the linear one. We give a method which lets us prove that there are planar polynomial centers of degree l with at least 2[(l - 2)/2] critical periods as well as study concrete families of potential, reversible and Lienard centers. This last case is studied in more detail and we prove that the number of critical periods obtained with our approach does not. increases with the order of the perturbation. (C) 2007 Elsevier Ltd. All rights reserved.

Interferência de Brachiaria Ruziziensis sobre plantas daninhas em sistema de consórcio com milho

Regarding tropical forage plants, the specie Brachiaria ruziziensis are prominence for to be most acceptable for cattle when compared with others Brachiaria species, besides the excellent competitive ability with weeds. Then, this study aimed to evaluate the effects of Brachiaria ruziziensis density in intercropping with corn crop, about weeds control and weeds development in the crop-cattle integration system. The experiment was realized during the period between December/2007 to May/2008, in the experimental area of Escola Superior de Agricultura "Luiz de Queiroz", Piracicaba - SP. The treatment was composed in a factorial arrangement, by combination of four Brachiaria ruziziensis density (0, 10, 15 and 20 kg ha(-1)) and three weed species ((Ipomoea grandifolia, Digitaria horizontalis e Cenchrus echinatus), in intercropping with corn crop. The evaluations realized were: weed infestation (density m(-2)), the dry biomass (g plant(-1)) and leaf area (cm(2) plant(-1)). It was noted that Brachiaria ruziziensis reduced the all of weeds infestation evaluated. Also, it was checked that Digitaria horizontalis and Ipomoea grandifolia were the weeds with most difficult control.

Weed-soybean interference studies in Brazil

Recently, a notable shift in weed patterns has occurred in some soybean growing regions, as a result of tillage system change and herbicide use. The weed communities are very diversified and strongly interfere with soybean growth and productivity, especially when the shading of superior leaves of the canopy occurs. Some changes to certain agricultural practices, such as cultivars, row spacing and sowing density, were studied and were considered suitable for the establishment of an integrated weed management system under Brazilian conditions. -from Author

Interference competition between ants (Hymenoptera: Formicidae) in Amazonian clearings

The first case of interference competition through soil dumping in South America is documented between Ectatomma quadridens and Pheidole fallax in Amazonian forest clearings. Workers of the diurnally active E. quadridens arrive at nests of P. fallax at dawn, and begin to fill up nest entrances with soil. During the day, E. quadridens workers remain stationary on the closed nest of P. fallax, and fill soil at the first signs of nest openings. Colonies of P. fallax distant from E. quadridens nests are active for 24 hrs; those near E. quadridens nests are limited for foraging nocturnally after opening nest entrances. This pattern was not found between heterospecific colonies at greater distances from the camp midden, according with the prediction that interference competition is more probable as resources become more concentrated. Colonies of P. fallax near E. quadridens nests located near the camp midden had a net forage intake of 60% of those located in areas without E. quadridens. -Author

Interference competition and scavenging by Crematogaster ants (Hymenoptera: Formicidae) associated with the webs of the social spider Anelosimus eximius (Araneae: Theridiidae) in the central Amazon

Crematogaster cf. victima is a common inhabitant in the sheet web nests of the social spider Anelosimus eximius in the central Amazon basin near Manaus. A number of other ant species were found foraging on the non-sticky webs of A. eximius, but none of these reached the web occupation frequency found in C. cf. victima, nor, with the exception of an unidentified species of Pheidole, did they form satellite nests in the web, as did this species. Many prey which escaped the knock-down threads of the sheet web of A. eximius colonies were captured by ants in the lower web portions which they dominated. Furthermore, prey which were rejected by A. eximius, especially large, heavily sclerotized beetles, were also consumed by this ant. Repeated observations and experiments suggest that C. cf. victima is able to deter A. eximius activity through aerial venom release. Resources lost by A. eximius colonies to ants, especially C. cf. victima, in colonial web area and prey, may pose significant costs and may reduce colony growth.

Competition between spin, charge, and bond waves in a Peierls-Hubbard model

We study a one-dimensional extended Peierls-Hubbard model coupled to intracell and intercell phonons for a half-filled band. The calculations are made using the Hartree-Fock and adiabatic approximations for arbitrary temperature. In addition to static spin, charge, and bond density waves, we predict intermediate phases that lack inversion symmetry, and phase transitions that reduce symmetry on increasing temperature.