A list of commercial fish species from Santarem, state of Para, Brazil

A list, comprising 129 species in 23 families, is presented of the fish commonly caught in 1992/93 in the commercial fisheries around Santarem, Para State, Brazil. The most important families were the Pimelodidae (22 spp.), Cichildae (20) and Serrasalmidae (15), and six species contribute over 50% of the catch in weight

Áreas Potenciais à Formação De Corredores Ecológicos Entre Remanescentes De Mata Atlântica

In Brazil, the remaining areas of Atlantic Forest are intensely fragmented. The connection of forest fragments through ecological corridors is an important step in biodiversity conservation. Certain areas are more resilient, and in those areas, natural forest regeneration, for example, can be encouraged. The aim of this study was to identify areas of greater resilience in order to support the connection of Atlantic Forest fragments with ecological corridors. Forest fragments in the municipality of Paraíba do Sul, in the state of Rio de Janeiro, were mapped using the supervised maximum likelihood classification of an Operational Land Imager (OLI)/Landsat-8 sensor image. Next, we analyzed the influence of terrain attributes (aspect, incident solar radiation, slope, and curvature profile) on natural regeneration. The areas with the greatest potential to achieve natural regeneration and to form ecological corridors were indicated through fuzzy membership functions. Within Paraíba do Sul, 31% of the territory is covered by vegetation in different stages of regeneration. Recordings were made of 1,251 forest fragments in a middle or advanced stage of regeneration. These fragments are usually situated in the southeast, south, and southwest aspects, in areas that receive the least amount of global solar radiation (Wh·m-2) per year, and on slopes with an angle of inclination greater than 20%. The adjustment of fuzzy functions identified 17,327.5 ha with a tendency to recover, and which are therefore strategic areas in the development of ecological corridors. © 2016, Sociedade de Investigacoes Florestais. All rights reserved.40580381

Density functional theory based screening of ternary alkali-transition metal borohydrides: A computational material design project

The dissociation of molecules, even the most simple hydrogen molecule, cannot be described accurately within density functional theory because none of the currently available functionals accounts for strong on-site correlation. This problem led to a discussion of properties that the local Kohn-Sham potential has to satisfy in order to correctly describe strongly correlated systems. We derive an analytic expression for the nontrivial form of the Kohn-Sham potential in between the two fragments for the dissociation of a single bond. We show that the numerical calculations for a one-dimensional two-electron model system indeed approach and reach this limit. It is shown that the functional form of the potential is universal, i.e., independent of the details of the two fragments.We acknowledge funding by the Spanish MEC (Grant No. FIS2007-65702-C02-01), “Grupos Consolidados UPV/EHU del Gobierno Vasco” (Grant No. IT-319-07), and the European Community through e-I3 ETSF project (Grant Agreement No. 211956).Peer reviewe

Magnetism of graphene and carbon nanotubes substitutionally doped with Ni

Resumen del trabajo presentado al Computational Studies of Defects in Nanoscale Carbon Materials Workshop (DNC), celebrado en Lausanne (Switzerland) del 11 al 13 de mayo de 2009.Most popular CNT growth methods rely on the use of catalyst based on transition metals (particularly Ni, Co and Fe). Even after many hours of acid treatment the catalyst is not completely removed. Several works show that remnant metal is in the form of isolated atoms and strongly bound to the carbon layer occupying substitutional positions. Therefore is of paramount importance to study the magnetism of substitutional species in graphenic systems. Here, we report a first-principles study of the structural, electronic and magnetic properties of substitutionated Ni atoms in graphenic systems by making spin-polarized calculations. We have observed that the magnetic moment of Ni-doped graphene layers can be controlled applying mechanical deformations that break the hexagonal symmetry of the graphene layer in the appropriate way. We analyze in detail the response of the curvature of the layer with the doping. We do this by comparing the results obtained for graphene and single-walled carbon nanotubes, and analyzing the changes of the electronic structure. We find that flat graphene layers doped with substitutional Ni present a zero magnetic moment. This is already an unexpected result. However, the magnetic moment of Ni can be switched on by applying curvature to the structure. It is interesting to note here that curvature is the parameter connecting two, in principle topologically equivalent, nanostructures of carbon: carbon nanotubes and graphene nanoribbons. Furthermore, we find that the Ni magnetic moment becomes also a signature of the metallicity of the structure: only metallicstructures develop a magnetic moment. We think that these results are of great interest for a large number of scientists working in the field of magnetic and electronic properties of graphene and related materials.Peer reviewe