Hierarchical Spatial Organization of Geographical Networks

In this work we propose the use of a hirarchical extension of the polygonality index as a means to characterize and model geographical networks: each node is associated with the spatial position of the nodes, while the edges of the network are defined by progressive connectivity adjacencies. Through the analysis of such networks, while relating its topological and geometrical properties, it is possible to obtain important indications about the development dynamics of the networks under analysis. The potential of the methodology is illustrated with respect to synthetic geographical networks.Comment: 3 page, 3 figures. A wokring manuscript: suggestions welcome

Surviving opinions in Sznajd models on complex networks

The Sznajd model has been largely applied to simulate many sociophysical phenomena. In this paper we applied the Sznajd model with more than two opinions on three different network topologies and observed the evolution of surviving opinions after many interactions among the nodes. As result, we obtained a scaling law which depends of the network size and the number of possible opinions. We also observed that this scaling law is not the same for all network topologies, being quite similar between scale-free networks and Sznajd networks but different for random networks.Comment: 9 pages, 3 figure

Produção de caprinos de corte para agricultura familiar.

bitstream/item/53182/1/Folder-Producao-de-caprinos.pd

Avaliação do desempenho de um pivo central da baixa pressão equipado com tubos de descida.

At the Corn and Sorghum National Research Center in Sete Lagoas, Minas Gerais State, an evaluation was made of the performance of a low pressure central pivot equipped with drop sparay, operating at 100% of its displacement capacity. The tests carried out were the following: without drop spray; drop spray of 1.2m; 2.0m and 2.6m lenght. For each test, the uniformity coefficients of Christiansen (CUC) and distribution (CUD), the application efficiency, in potential (EPa), and the highest precipitation intensity were determined. It was concluded that: The lenght of drop spray did not affect distribution uniformity; The collected water plate at the end of the pivot line showed a large variation; Topographic characteristics influenced distribution uniformity; Drop spray increased application efficiency, in potential, reducing pressure at the diffusor exit. Proximity of the diffusor to the ground decreased the covering diameter and increase precipitation density

Beyond the average: Detecting global singular nodes from local features in complex networks

Deviations from the average can provide valuable insights about the organization of natural systems. The present article extends this important principle to the systematic identification and analysis of singular motifs in complex networks. Six measurements quantifying different and complementary features of the connectivity around each node of a network were calculated, and multivariate statistical methods applied to identify singular nodes. The potential of the presented concepts and methodology was illustrated with respect to different types of complex real-world networks, namely the US air transportation network, the protein-protein interactions of the yeast Saccharomyces cerevisiae and the Roget thesaurus networks. The obtained singular motifs possessed unique functional roles in the networks. Three classic theoretical network models were also investigated, with the Barab\'asi-Albert model resulting in singular motifs corresponding to hubs, confirming the potential of the approach. Interestingly, the number of different types of singular node motifs as well as the number of their instances were found to be considerably higher in the real-world networks than in any of the benchmark networks

Conhecendo espécies de plantas da Amazônia: ingá-costela (Inga capitata desv. - Leguminosae).

bitstream/item/102979/1/COM-TEC-243.pd

Avaliação agronômica de oito genótipos de Sisal (agave ssp.).

bitstream/CNPA/21024/1/COMTEC340.pd

Knowledge Acquisition by Networks of Interacting Agents in the Presence of Observation Errors

In this work we investigate knowledge acquisition as performed by multiple agents interacting as they infer, under the presence of observation errors, respective models of a complex system. We focus the specific case in which, at each time step, each agent takes into account its current observation as well as the average of the models of its neighbors. The agents are connected by a network of interaction of Erd\H{o}s-Renyi or Barabasi-Albert type. First we investigate situations in which one of the agents has a different probability of observation error (higher or lower). It is shown that the influence of this special agent over the quality of the models inferred by the rest of the network can be substantial, varying linearly with the respective degree of the agent with different estimation error. In case the degree of this agent is taken as a respective fitness parameter, the effect of the different estimation error is even more pronounced, becoming superlinear. To complement our analysis, we provide the analytical solution of the overall behavior of the system. We also investigate the knowledge acquisition dynamic when the agents are grouped into communities. We verify that the inclusion of edges between agents (within a community) having higher probability of observation error promotes the loss of quality in the estimation of the agents in the other communities.Comment: 10 pages, 7 figures. A working manuscrip

Fertirrigação com alternância de fontes de nitrogênio amídica e nítrica em bananeira Grand Naine.

Como todas as culturas, a bananeira necessita de condições favoráveis para se desenvolver e obter boa produtividade, exigindo calor constante, elevada umidade relativa (>80%) e precipitações bem distribuídas (100 a 180 mm/mês) de acordo com Silva et al., (2006). Além disso, é indispensável a aplicação de fertilizantes podendo-se fazer uso da fertirrigação em áreas com cultivo irrigado. O Nitrogênio é um dos nutrientes mais absorvidos e necessários para o crescimento e produção da bananeira, pela elevada quantidade absorvida e exportada desse nutriente pelos frutos (BORGES et al, 1997; SILVA et al., 1999). Na fertirrigação nitrogenada, as fontes mais utilizadas são sais inorgânicos de amônio, nitrato e uréia, (BARBOSA FILHO et al., 2004). Essas, comparadas ao nitrato de cálcio, são de menor custo financeiro para o produtor porém, causam efeitos indesejáveis no solo tais como diminuição do pH e salinização do solo (MALAVOLTA et al., 1989). O nitrato de cálcio apresenta um índice salino baixo comparado a outras fontes de nitrogênio. Este trabalho teve como objetivo analisar o efeito de diferentes alternâncias de aplicação de duas fontes nitrogenadas por fertirrigação sobre as variáveis de crescimento e de produção da bananeira cv. Grande Naine.pdf 219