961 resultados para diversity of species
Resumo:
The influence of the thalamus on the diversity of cortical activations is investigated in terms of the Ising model with respect to progressive levels of cortico-thalamic connectivity. The results show that better diversity is achieved at lower modulation levels, being higher than those obtained with counterpart network models.
Resumo:
The adsorption of pyridine (py) on Fe, Co, Ni and Ag electrodes was studied using surface-enhanced Raman scattering (SERS) to gain insight into the nature of the adsorbed species. The wavenumber values and relative intensities of the SERS bands were compared to the normal Raman spectrum of the chemically prepared transition metal complexes. Raman spectra of model clusters M(4)(py) (four metal atoms bonded to one py moiety) and M(4)(alpha-pyridil) where M = Ag, Fe, Co or Ni were calculated by density functional theory (DFT) and used to interpret the experimental SERS results. The similarity of the calculated M(4)(py) spectra with the experimental SERS spectra confirm the molecular adsorption of py on the surface of the metallic electrodes. All these results exclude the formation of adsorbed alpha-pyridil species, as suggested previously. Copyright (C) 2009 John Wiley & Sons, Ltd.
Resumo:
The implications of diversity still raise confusion in the cultural debate. We address them from both a formal and conceptual viewpoints, putting in check the validity of some arguments. We conclude that: measuring diversity demands key decisions and careful statistical procedures; ignorance on optimal diversity levels and on ways to generate them is widespread in the cultural field; there is no support for cultural diversity as something associated to fair economic and political systems; restriction to sheer economics requires the establishment of links between diversity and measurable properties – something rather incipient. Diversity, as a social choice, should be distinguished from it as an economic value.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Variation in seed size is often observed in samples of eucalypt seeds and this leads to heterogeneous populations of plants, principally through variation in the early stages of plant development. It follows that samples of seeds more uniform in size could produce more uniform populations of plants. In studies of Eucalyptus globulus ssp. globulus it was of interest to determine whether or not the genetic diversity within a population, through the use of isozyme markers, was altered in the subpopulations developed from seeds of different size classes. A commercial sample of seed was separated by seed size into three subpopulations and the percentage germination and mean fresh weight of the seedlings were determined. Proteins extracted from leaves of the seedlings were separated by electrophoresis and tested for activity of eight different enzymes. These eight enzymes showed activity at 20 loci and mean genetic diversity and fixation index were determined using 13 of these loci. The subpopulation of the smallest seeds contained a greater proportion of abnormal seeds and had a lower percentage germination and plant weight compared to the other subpopulations. No significant differences were found in the number of alleles per locus, percentage of polymorphic loci, mean heterozygosity. The major part of the endogamy, indicated by F statistic, was found within the subpopulations: F-(IS) = 0.518; F-(ST) = 0.010 and F(IT) = 0.523. We conclude that the use of seeds of uniform size will lead to more uniform germination and plant growth without alteration in overall genetic diversity.
Resumo:
The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of São Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the 'Associação Paulista de Criadores de Ovinos' (ASPACO; São Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)