3,595 research outputs found

    Biological control of taro scarab beetle (Papuanauninodis Coleoptera: Scarabaeidae) instars via Scoliid and Voria Tachinidae parasitoid wasps

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    Scoliid and Voria Tachinidae parasitoid wasps are shown to be able to control the population of the Taro Scarab beetle (Papuanauninodis, Coleoptera: Scarabaeidae) larvae using a newly created continuous-time simulation model based on non-linear ordinary differential equations that track the populations of the beetle’s life cycle stages: egg, larva, pupa, adult and the populations of the two parasitoid wasps. Due to the fact that the scarab beetles are, relatively speaking, long lived it is challenging to drive down the adult population below the environmental carrying capacity. Mortality and predator/prey capture rates are modelled using the Weibull and Pascal probability distribution functions, respectively. We suggest the use of a virus or fungi to drive down the population of the adult beetles, the ambition being to avoid the use of pesticides so as to produce higher quality food that doesn’t damage human health via chemical residues

    Poisson statistics of PageRank probabilities of Twitter and Wikipedia networks

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    We use the methods of quantum chaos and Random Matrix Theory for analysis of statistical fluctuations of PageRank probabilities in directed networks. In this approach the effective energy levels are given by a logarithm of PageRank probability at a given node. After the standard energy level unfolding procedure we establish that the nearest spacing distribution of PageRank probabilities is described by the Poisson law typical for integrable quantum systems. Our studies are done for the Twitter network and three networks of Wikipedia editions in English, French and German. We argue that due to absence of level repulsion the PageRank order of nearby nodes can be easily interchanged. The obtained Poisson law implies that the nearby PageRank probabilities fluctuate as random independent variables.Comment: 4 pages, 4 figures http://www.quantware.ups-tlse.fr

    The Reality of Casimir Friction

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    For more than 35 years theorists have studied quantum or Casimir friction, which occurs when two smooth bodies move transversely to each other, experiencing a frictional dissipative force due to quantum electromagnetic fluctuations, which break time-reversal symmetry. These forces are typically very small, unless the bodies are nearly touching, and consequently such effects have never been observed, although lateral Casimir forces have been seen for corrugated surfaces. Partly because of the lack of contact with phenomena, theoretical predictions for the frictional force between parallel plates, or between a polarizable atom and a metallic plate, have varied widely. Here we review the history of these calculations, show that theoretical consensus is emerging, and offer some hope that it might be possible to experimentally confirm this phenomenon of dissipative quantum electrodynamics.Comment: 12 pages, 2 figure
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