Controle de plantas daninhas em pomares de cajueiro.

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Scaling laws of human interaction activity

Even though people in our contemporary, technological society are depending on communication, our understanding of the underlying laws of human communicational behavior continues to be poorly understood. Here we investigate the communication patterns in two social Internet communities in search of statistical laws in human interaction activity. This research reveals that human communication networks dynamically follow scaling laws that may also explain the observed trends in economic growth. Specifically, we identify a generalized version of Gibrat's law of social activity expressed as a scaling law between the fluctuations in the number of messages sent by members and their level of activity. Gibrat's law has been essential in understanding economic growth patterns, yet without an underlying general principle for its origin. We attribute this scaling law to long-term correlation patterns in human activity, which surprisingly span from days to the entire period of the available data of more than one year. Further, we provide a mathematical framework that relates the generalized version of Gibrat's law to the long-term correlated dynamics, which suggests that the same underlying mechanism could be the source of Gibrat's law in economics, ranging from large firms, research and development expenditures, gross domestic product of countries, to city population growth. These findings are also of importance for designing communication networks and for the understanding of the dynamics of social systems in which communication plays a role, such as economic markets and political systems.Comment: 20+7 pages, 4+2 figure

Agricultura irrigada no Ceará: recursos físicos, humanos e produção técnico-científica.

Agricultura Irrigada no Ceara; Recursos fisicos; Solos irrigaveis; Aerea implantada com irrigacao e culturas irrigadas; Aerea experimental com agricultura irrigada; Sistemas de irrigacao utilizados; Recursos humanos; Producao tecnico-cientifica por linha de pesquisa; Manejo de irrigacao; Desenvolvimento e avaliacao de equipamento e sistemas de irrigacao; Parametros basicos do solo para irrigacao e drenagem; Informatica na irrigacao e drenagem; Avaliacao socio-economica da irrigacao.bitstream/item/35433/1/Dc-025.pd

Desenvolvimento de plantas jovens de coqueiro anão (Cocos nucifera L.) submetidas a diferentes regimes de irrigação.

O deficit hidrico no solo, causado pela ma distribuicao das precipitacoes ao longo do ano, constitui um dos principais fatores que contribuem para a baixa produtividade do coqueiro nas diferentes regioes onde e cultivado. Devido a isto, tem aumentado significativamente nos ultimos anos o uso da irrigacao nessa cultura, sobretudo nos plantios do coqueiro anao, cujos frutos se destinam ao crescente mercado de agua de coco, "in natura".bitstream/CNPAT-2010/5373/1/Pa-023.pd

Irrigação localizada (microirrigação).

Irrigacao localizada ou microirrigacao; partes constituintes; bombeamento; bomba centrifuga; sistema de filtragem; concepcao de um sistema de irrigacao; fertirrigacao.bitstream/CNPAT-2010/4306/1/Dc-023.pd