Paleodistributions and Comparative Molecular Phylogeography of Leafcutter Ants (Atta spp.) Provide New Insight into the Origins of Amazonian Diversity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Variation in liana abundance and biomass along an elevational gradient in the tropical Atlantic Forest (Brazil)

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

Genetic structure in a tropical lek-breeding bird, the blue manakin (Chiroxiphia caudata) in the Brazilian Atlantic Forest

Determining the genetic structure of tropical bird populations is important for assessing potential genetic effects of future habitat fragmentation and for testing hypotheses about evolutionary mechanisms promoting diversification. Here we used 10 microsatellite DNA loci to describe levels of genetic differentiation for five populations of the lek-mating blue manakin (Chiroxiphia caudata), sampled along a 414-km transect within the largest remaining continuous tract of the highly endangered Atlantic Forest habitat in southeast Brazil. We found small but significant levels of differentiation between most populations. F-ST values varied from 0.0 to 0.023 (overall F-ST = 0.012) that conformed to a strong isolation by distance relationship, suggesting that observed levels of differentiation are a result of migration-drift equilibrium. N(e)m values estimated using a coalescent-based method were small (<= 2 migrants per generation) and close to the minimum level required to maintain genetic similarity between populations. An implication of these results is that if future habitat fragmentation reduces dispersal between populations to even a small extent, then individual populations may undergo a loss of genetic diversity due to an increase in the relative importance of drift, since inbreeding effective population sizes are relatively small (N-e similar to 1000). Our findings also demonstrate that population structuring can occur in a tropical bird in continuous habitat in the absence of geographical barriers possibly due to behavioural features of the species.

Comments about some species abundance patterns: classic, neutral, and niche partitioning models

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Population genetic structure revealed by a school of the freshwater migratory fish, Brycon hilarii

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diets of ocelots (Leopardus pardalis), margays (L-wiedii), and oncillas (L-tigrinus) in the Atlantic rainforest in southeast Brazil

Felids play an important role in structuring the prey community, and thus in the dynamics of the plant community in tropical forests. The diets of three species of small cats, Leopardus pardalis (ocelot), L. wiedii (margay), and L. tigrinus (oncilla) were investigated by analysis of scats and regurgitations during a one-year study at Parque Estadual Serra do Mar, Nucleo Santa Virginia, southeastern Brazil. Small non-volant mammals were the most frequent prey in all the diets. The diets of the three cats were similar but although they consumed the same prey items, they showed differential use of them. Ocelots consumed more reptiles than the other species, oncillas preyed on birds and arboreal marsupials, whereas margays were generalists.

New Insight into the Mechanism of Action of Wasp Mastoparan Peptides: Lytic Activity and Clustering Observed with Giant Vesicles

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

On asymptotic solutions of integrable wave equations

Asymptotic 'soliton train' solutions of integrable wave equations described by inverse scattering transform method with second-order scalar eigenvalue problem are considered. It is shown that if asymptotic solution can be presented as a modulated one-phase nonlinear periodic wavetrain, then the corresponding Baker-Akhiezer function transforms into quasiclassical eigenfunction of the linear spectral problem in weak dispersion limit for initially smooth pulses. In this quasiclassical limit the corresponding eigenvalues can be calculated with the use of the Bohr Sommerfeld quantization rule. The asymptotic distributions of solitons parameters obtained in this way specify the solution of the Whitham equations. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Miscibility in a degenerate fermionic mixture induced by linear coupling

We consider a one-dimensional mean-field-hydrodynamic model of a two-component degenerate Fermi gas in an external trap, each component representing a spin state of the same atom. We demonstrate that the interconversion between them (linear coupling), imposed by a resonant electromagnetic wave, transforms the immiscible binary gas into a miscible state, if the coupling constant, kappa, exceeds a critical value, kappa(cr). The effect is predicted in a variational approximation, and confirmed by numerical solutions. Unlike the recently studied model of a binary Bose-Einsten condensate with the linear coupling, the components in the immiscible phase of the binary fermion mixture never fill two separated domains with a wall between them, but rather form antilocked (pi-phase-shifted) density waves. Another difference from the bosonic mixture is spontaneous breaking of symmetry between the two components in terms of the numbers of atoms in them, N(1) and N(2). The latter effect is characterized by the parameter nu equivalent to(N(1)-N(2))/(N(1)+N(2)) (only N(1)+N(2) is a conserved quantity), the onset of miscibility at kappa >=kappa(cr) meaning a transition to nu equivalent to 0. At kappa

QUASIDISTRIBUTIONS and COHERENT STATES FOR FINITE-DIMENSIONAL QUANTUM SYSTEMS

In recent years, an approach to discrete quantum phase spaces which comprehends all the main quasiprobability distributions known has been developed. It is the research that started with the pioneering work of Galetti and Piza, where the idea of operator bases constructed of discrete Fourier transforms of unitary displacement operators was first introduced. Subsequently, the discrete coherent states were introduced, and finally, the s-parametrized distributions, that include the Wigner, Husimi, and Glauber-Sudarshan distribution functions as particular cases. In the present work, we adapt its formulation to encompass some additional discrete symmetries, achieving an elegant yet physically sound formalism.

Explicação do conteúdo: elemento estruturante da apredizagem eficaz

Neste artigo busca-se mostrar a construção de uma categoria explicativa do trabalho docente denominada explicação do conteúdo, a partir de representações de alunos da Habilitação Magistério sobre as práticas pedagógicas de seus professores, cuja formulação assumiu a função de elemento estruturante básico do trabalho docente eficaz. Trata-se de pesquisa de abordagem qualitativa em que os instrumentos utilizados para coleta de dados foram observação em sala de aula e entrevista semi-estruturada.

Diversidade e estrutura genética espacial em duas populações de Myracrodruon urundeuva Fr. All. sob diferentes condições antrópicas

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

Sucessão da comunidade de algas perifíticas em reservatório oligotrófico tropical (São Paulo, Brasil): comparação entre período seco e chuvoso

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

Contribuições da teoria marxista para a educação ambiental crítica

O artigo apresenta algumas das principais contribuições da teoria marxista para a educação ambiental, considerando que a prática educativa no Brasil se constituiu em diálogo com concepções pedagógicas e autores inseridos neste campo. Iniciamos com uma breve contextualização da produção de inspiração crítica (estritamente marxista ou não) e as disputas teóricas inseridas na educação ambiental. Logo após, discorremos sobre a influência e a apropriação das pedagogias críticas e de conceitos estruturantes da concepção marxiana de educação na formulação teórico-metodológica em educação ambiental. Como síntese e conclusão, argumentamos sobre a importância do materialismo histórico-dialético nas discussões ambientais contemporâneas, refletindo criticamente sobre como ele aí se apresenta, particularmente na educação ambiental.

Water at interfaces and its influence on the electrical properties of adsorbed films

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