PAIRWISE VELOCITIES OF GALAXIES IN THE CFA AND SSRS2 REDSHIFT SURVEYS

(compressed version) We combine the CfA Redshift Survey (CfA2) and the Southern Sky Redshift Survey (SSRS2) to estimate the pairwise velocity dispersion of galaxies \sig12 on a scale of \sim 1 \hmpc. Both surveys are complete to an apparent magnitude limit $B(0)=15.5$. Our sample includes 12,812 galaxies distributed in a volume 1.8 \times 10^6 \hmpc3. We conclude: 1) The pairwise velocity dispersion of galaxies in the combined CfA2+SSRS2 redshift survey is \sig12=540 \kms \pm 180 \kms. Both the estimate and the variance of \sig12 significantly exceed the canonical values \sig12=340 \pm40 measured by Davis \& Peebles (1983) using CfA1. 2) We derive the uncertainty in \sig12 from the variation among subsamples with volumes on the order of $7 \times 10^5$ \hmpc3. This variation is nearly an order of magnitude larger than the formal error, 36 \kms, derived using least-squares fits to the CfA2+SSRS2 correlation function. This variation among samples is consistent with the conclusions of Mo \etal (1993) for a number of smaller surveys and with the analysis of CfA1 by Zurek \etal (1994). 3) When we remove Abell clusters with $R\ge1$ from our sample, the pairwise velocity dispersion of the remaining galaxies drops to 295 \pm 99 \kms. Thus the dominant source of variance in \sig12 is the shot noise contributed by dense virialized systems. 4) The distribution of pairwise velocities is consistent with an isotropic exponential with velocity dispersion independent of scale.Comment: 61 pages uuencoded, compressed postscript in 5 pieces. Also available in one piece at http://www.dao.nrc.ca/DAO/SCIENCE/science.htm

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

What are the Best Hierarchical Descriptors for Complex Networks?

This work reviews several hierarchical measurements of the topology of complex networks and then applies feature selection concepts and methods in order to quantify the relative importance of each measurement with respect to the discrimination between four representative theoretical network models, namely Erd\"{o}s-R\'enyi, Barab\'asi-Albert, Watts-Strogatz as well as a geographical type of network. The obtained results confirmed that the four models can be well-separated by using a combination of measurements. In addition, the relative contribution of each considered feature for the overall discrimination of the models was quantified in terms of the respective weights in the canonical projection into two dimensions, with the traditional clustering coefficient, hierarchical clustering coefficient and neighborhood clustering coefficient resulting particularly effective. Interestingly, the average shortest path length and hierarchical node degrees contributed little for the separation of the four network models.Comment: 9 pages, 4 figure

Avaliação da tecnologia zoneamento de risco climático da cultura do sorgo no Estado de Pernambuco.

O zoneamento da área de risco climático do sorgo no Estado de Pernambuco veio atender a uma demanda do setor avícola que estava crescendo mas seus custos eram altos pela dependência do milho para a produção da ração das aves. O milho é muito sensível à estiagem enquanto o sorgo é cultivado em áreas muito secas e/ou muito quentes próprias da região do Semi-árido e Sertão, onde a produtividade de outros cereais é antieconômica. Este trabalho fez uma avaliação dos impactos da tecnologia do zoneamento do risco climático da cultura do sorgo nas áreas do semi-árido de Pernambuco, sob os aspectos econômicos, sociais e ambientais. O estudo abrangeu um período de três anos, empregando a Metodologia de Referência da Embrapa. Sob o ponto de vista econômico, o resultado encontrado foi de um grande aumento da área plantada, da quantidade produzida de sorgo e da renda gerada. No aspecto social houve aumento de emprego. Quanto ao aspecto ambiental não houve preocupação na conservação e recuperação dos recursos naturais.bitstream/CNPS-2010/14746/1/bpd139-2009-avaliacao-zoneamento-sorgo.pd

Efeito do uso de ducha, antes e após o transporte, sobre a qualidade da carne dos suínos.

Projeto/Plano de Ação: 02.06.01.001

Perspectives of Liriomyza biological control in Brazil.

In this work the results of a ten - year research on Liriomyza parasitoids in Brazil are reported

Biomass and energy yield of leguminous trees cultivated in Amazonas.

Biomassa e produtividade energética de leguminosas arbóreas cultivadas no Amazonas. As florestas energéticas representam alternativa à dependência do uso de combustíveis fósseis para a produção de energia. O bom desempenho dessas florestas deve considerar a seleção de espécies de rápido crescimento, alta produtividade em biomassa e rendimento energético. O objetivo foi investigar o crescimento e a produtividade energética de Acacia auriculiformis e Acacia mangium em plantios florestais de curta rotação no Amazonas

Broca-do-café: Previsão de Infestação e Recomendações de Controle para Safra 2001/2002 no Estado de Rondônia.

Trabalho reúne informações sobre a broca-do-café, em plantações de café conilon, em Rondônia. Tópicos trabalhados: Infestação da broca na safra 2001; Previsão de infestação na safra 2001/2002; Amostragem para avaliação da infestação; Recomendações para o controle da broca-do-café.bitstream/item/100456/1/CT55-brocadocafe.pd

Abundances on the Main Sequence of Omega Centauri

Abundance ratios of carbon, nitrogen and strontium relative to iron, calculated using spectrum synthesis techniques, are given for a sample of main sequence and turnoff stars that belong to the globular cluster omega Centauri. The variations of carbon, nitrogen and/or strontium show several different abundance patterns as a function of [Fe/H]. The source of the enhancements/depletions in carbon, nitrogen and/or strontium may be enrichment from asymptotic giant branch stars of low (1--3 solar masses) and intermediate (3--8 solar masses) mass. Massive rotating stars which produce excess nitrogen without carbon and oxygen overabundances may also play a role. These abundances enable different contributors to be considered and incorporated into the evolutionary picture of omega Cen.Comment: 43 Pages, 13 Figures. Accepted for publication in Ap