Time filter

Source Type

Tejerina-Garro F.L.,Pontifical Catholic University of Goias | de Merona B.,Institut Universitaire de France
Neotropical Ichthyology | Year: 2010

The objective of this study is to verify the existence of a seasonal pattern of variation in the fish assemblages of a tropical river using taxonomic and functional descriptors. Fish were sampled using gillnets at two sites on the Comte River, a large-sized river 254.8 km long, flowing entirely through rainforest areas of French Guiana. Samplings were conducted every other month from August 1998 to July 2000. Four types of fish assemblage descriptors were used: the species descriptor (number of individual fish of each species in the sample); the family descriptor (number of individual fish of each family in the sample); the trophic descriptor (distribution of the fish biomass in each feeding guild) and the specific maximum observed size - MOS (number of individual fish in each of four classes of MOS: < 100 mm; 101-200 mm; 201-300 mm; > 300 mm). Results point out that changes in the fish assemblage are related to water level oscillations. The role of migration seems to be weak and is limited to trophic displacements characteristic of few species. In the low-water season, characterized by weak water level oscillation, fish species and families belonging to piscivorous or aquatic invertivorous guilds were predominant, whereas in the high-water season the environment is submitted to strong variations caused by fast and large water level oscillations, and the fish assemblage was characterized by species or families with an opportunistic omnivorous diet. © 2010 Sociedade Brasileira de Ictiologia.

Carvalho R.A.,Federal University of Goais | Tejerina-Garro F.L.,Pontifical Catholic University of Goias
Ecology of Freshwater Fish | Year: 2015

In this study, we investigated functional structure patterns of tropical headwater and river fish assemblages. We hypothesised that environmental conditions are primarily structuring headwater streams leading to functionally clustered assemblages, whereas processes that favour functional overdispersion would guide river assemblages. For 27 headwater streams and 22 rivers, we used eight functional traits for calculating two functional indexes: mean pairwise distance (MPD) and net relatedness index (NRI). We performed linear regressions between indexes and species richness, a multiple regression between NRI and eight environmental variables and a variation partitioning to disentangle the role of environment and space on NRI. Our findings indicate that fish assemblages of headwaters are structured by environmental conditions as most assemblages in this habitat displayed a tendency to clustering and MPD/NRI were not correlated with species diversity, whereas the opposite pattern was observed for river habitat. Four environmental variables (channel depth, water velocity, dissolved oxygen and turbidity) explain 56% of functional structure variation. These variables seem to function as selective filters in headwaters, whereas channel depth may be determinant for functional overdispersion of river fish assemblages. Components associated with space are also influencing the functional structure. Limitations of species dispersal through space (between both habitat types) appear as a possible cause to this. In this sense, both environmental conditions and processes linked with space are capable of influencing the functional structure of tropical headwater streams and river fish assemblages. © 2014 John Wiley & Sons A/S.

Afonso E.T.,Federal University of Goais | Afonso E.T.,Pontifical Catholic University of Goias | Minamisava R.,Federal University of Goais | Bierrenbach A.L.,Federal University of Goais | And 6 more authors.
Emerging Infectious Diseases | Year: 2013

Pneumonia is most problematic for children in developing countries. In 2010, Brazil introduced a 10-valent pneumococcal conjugate vaccine (PCV10) to its National Immunization Program. To assess the vaccine's effectiveness for preventing pneumonia, we analyzed rates of hospitalization among children 2-24 months of age who had pneumonia from all causes from January 2005 through August 2011. We used data from the National Hospitalization Information System to conduct an interrupted time-series analysis for 5 cities in Brazil that had good data quality and high PCV10 vaccination coverage. Of the 197,975 hospitalizations analyzed, 30% were for pneumonia. Significant declines in hospitalizations for pneumonia were noted in Belo Horizonte (28.7%), Curitiba (23.3%), and Recife (27.4%) but not in São Paulo and Porto Alegre. However, in the latter 2 cities, vaccination coverage was less than that in the former 3. Overall, 1 year after introduction of PCV10, hospitalizations of children for pneumonia were reduced.

Rodrigues C.G.,Pontifical Catholic University of Goias | Luzzi R.,University of Campinas
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2014

An analysis of the influence of geometry and size on the thermal conductivity in semiconductors, particularized to the study in Si and GaN, is presented. This is done in the framework of a higher-order generalized hydrodynamics (HOGH) of phonons in semiconductors, driven away from equilibrium by external sources. This HOGH is derived by the method of moments from a generalized Peierls-Boltzmann kinetic equation built in the framework of a Non-Equilibrium Statistical Ensemble Formalism. We consider the case of wires (cylindrical geometry) exploring the effect of size (radius), particularly in the nanometric scale when comparison with experiment is done. Maxwell times, which are quite relevant to define the hydrodynamic movement, are evidenced and characterized. © 2014 Elsevier B.V.

Silva R.C.,Pontifical Catholic University of Goias
Genetics and molecular research : GMR | Year: 2011

We examined the frequency of RsaI polymorphism of the ERβ gene in 54 patients diagnosed with endometriosis and 46 controls. Peripheral blood was collected from women undergoing laparoscopy with a confirmed diagnosis of endometriosis. Polymorphisms of the ERβ gene and p53 were assessed by PCR and analyzed on 2% agarose gel stained with ethidium bromide. The AG polymorphism genotype frequency in patients with endometriosis was 59.3%, with 40.7% GG. In the control group, the frequency of AG was 6.5%, with 93.5% GG. The frequency of heterozygous AG was nine times higher in patients with endometriosis than in the control group (P < 0.0001).

Discover hidden collaborations