14,299 research outputs found
Applications and Sexual Version of a Simple Model for Biological Ageing
We use a simple model for biological ageing to study the mortality of the
population, obtaining a good agreement with the Gompertz law. We also simulate
the same model on a square lattice, considering different strategies of
parental care. The results are in agreement with those obtained earlier with
the more complicated Penna model for biological ageing. Finally, we present the
sexual version of this simple model.Comment: For Int.J.Mod.Phys.C Dec. 2001; 11 pages including 6 fig
Site-dependent hydrogenation on graphdiyne
Graphene is one of the most important materials in science today due to its
unique and remarkable electronic, thermal and mechanical properties. However in
its pristine state, graphene is a gapless semiconductor, what limits its use in
transistor electronics. In part due to the revolution created by graphene in
materials science, there is a renewed interest in other possible graphene-like
two-dimensional structures. Examples of these structures are graphynes and
graphdiynes, which are two-dimensional structures, composed of carbon atoms in
sp2 and sp-hybridized states. Graphdiynes (benzenoid rings connecting two
acetylenic groups) were recently synthesized and some of them are intrinsically
nonzero gap systems. These systems can be easily hydrogenated and the relative
level of hydrogenation can be used to tune the band gap values. We have
investigated, using fully reactive molecular dynamics (ReaxFF), the structural
and dynamics aspects of the hydrogenation mechanisms of graphdiyne membranes.
Our results showed that the hydrogen bindings have different atom incorporation
rates and that the hydrogenation patterns change in time in a very complex way.
The formation of correlated domains reported to hydrogenated graphene is no
longer observed in graphdiyne cases.Comment: Submitted to Carbo
Análise da situação da ATEPA (Assistência Técnica e Extensão Pesqueira e Aquícola) no Tocantins: perspectivas e entraves.
O presente estudo tem como objetivo geral analisar a situação dos serviços de ATEPA (Assistência Técnica e Extensão Pesqueira e Aquícola) no Tocantins e, especificamente, mapear e caracterizar as empresas prestadoras de ATEPA; e caracterizar o perfil dos extensionistas que atuam no setor pesqueiro. O estudo tem caráter exploratório-descritivo utilizando-se de fontes primárias, com o apoio da técnica de entrevista semi-estruturada, além de fontes secundárias.Organizado por: Sílvio Ricardo Maurano; AQUACIÊNCIA 2012
Multifunctional Nanocomposites Based on Mesoporous Silica: Potential Applications in Biomedicine
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