41 research outputs found

    Desenvolvimento endógeno de criação de gado nos Camarões: Explorado o potencial das iniciativas locais para o desenvolvimento da criação de gado

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    Este livro e o filme que o acompanha (DVD: CTA no. 1456) fornecem uma introdução à abordagem do DECG (desenvolvimento endógeno de criação de gado) em África. Esta publicação é o resultado de um trabalho conjunto entre camponeses, agentes extensionistas e consultores realizado nos Camarões, debruçando-se sobre o papel multifacetado desempenhado pelo gado nas comunidades rurais e como os criadores de gado podem ficar mais informados e organizados

    Acceleration of lead ions in the CERN PS booster and the CERN PS

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    The new CERN Heavy Ion Accelerating Facility also requires besides a new Linac substantial modifications of existing accelerators. They are imposed by the low speed and the low intensity of the ion beam and, crucially at low energy, by the short lifetime of the partially stripped ions due to charge exchange with the atoms of the residual gas. The upgraded vacuum system hits the limits of a non-bakeable machine and consequently the acceleration had to be sped up by all means. In the Booster this led to injection and RF capture on a fast-rising magnet cycle and a new digital RF beam control system. Beam current transformers had to be replaced by new, heavily shielded ones. Other modifications include a new staircase magnet to distribute ions over the four Booster rings, lengthening of septa and kicker pulses, plus new, bakeable extraction septa and an energy stabilizing RF loop on the flat top in the CPS, and a stripper in the transfer line to the SPS

    IONS FOR LHC: STATUS OF THE INJECTOR CHAIN

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    The LHC will, in addition to proton runs, be operated with Pb ions and provide collisions at energies of 5.5 TeV per nucleon pair, i.e. more than 1.1 PeV per event, to experiments. The transformation of CERN's ion injector complex (Linac3-LEIR-PS-SPS) to allow collision of ions in LHC in 2008 is well under way. The status of these modifications and the latest results of commissioning will be presented. The remaining challenges are reviewed

    Geppetto: a reusable modular open platform for exploring neuroscience data and models

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    Geppetto is an open-source platform that provides generic middleware infrastructure for building both online and desktop tools for visualizing neuroscience models and data and managing simulations. Geppetto underpins a number of neuroscience applications, including Open Source Brain (OSB), Virtual Fly Brain (VFB), NEURON-UI and NetPyNE-UI. OSB is used by researchers to create and visualize computational neuroscience models described in NeuroML and simulate them through the browser. VFB is the reference hub for Drosophila melanogaster neural anatomy and imaging data including neuropil, segmented neurons, microscopy stacks and gene expression pattern data. Geppetto is also being used to build a new user interface for NEURON, a widely used neuronal simulation environment, and for NetPyNE, a Python package for network modelling using NEURON. Geppetto defines domain agnostic abstractions used by all these applications to represent their models and data and offers a set of modules and components to integrate, visualize and control simulations in a highly accessible way. The platform comprises a backend which can connect to external data sources, model repositories and simulators together with a highly customizable frontend.This article is part of a discussion meeting issue 'Connectome to behaviour: modelling C. elegans at cellular resolution'

    Ions for LHC: Towards Completion of the Injector Chain

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    The commissioning of CERN's ion injector complex [1] to allow 1.1 PeV collisions of ions in LHC is well under way. After the Low Energy Ion Ring (LEIR) in 2005 [2] and the Proton Synchrotron (PS) in 2006 [3], the Super Proton Synchrotron (SPS) has now been commissioned with the 'Early' ion beam, which should give a luminosity of 5×1025cm2s15×10^{25}cm^{-2}s^{-1} in the LHC. This paper summarizes the operation in 2007 of all the machines involved in the ion injection chain

    Allometry and Ecology of the Bilaterian Gut Microbiome.

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    Classical ecology provides principles for construction and function of biological communities, but to what extent these apply to the animal-associated microbiota is just beginning to be assessed. Here, we investigated the influence of several well-known ecological principles on animal-associated microbiota by characterizing gut microbial specimens from bilaterally symmetrical animals (Bilateria) ranging from flies to whales. A rigorously vetted sample set containing 265 specimens from 64 species was assembled. Bacterial lineages were characterized by 16S rRNA gene sequencing. Previously published samples were also compared, allowing analysis of over 1,098 samples in total. A restricted number of bacterial phyla was found to account for the great majority of gut colonists. Gut microbial composition was associated with host phylogeny and diet. We identified numerous gut bacterial 16S rRNA gene sequences that diverged deeply from previously studied taxa, identifying opportunities to discover new bacterial types. The number of bacterial lineages per gut sample was positively associated with animal mass, paralleling known species-area relationships from island biogeography and implicating body size as a determinant of community stability and niche complexity. Samples from larger animals harbored greater numbers of anaerobic communities, specifying a mechanism for generating more-complex microbial environments. Predictions for species/abundance relationships from models of neutral colonization did not match the data set, pointing to alternative mechanisms such as selection of specific colonists by environmental niche. Taken together, the data suggest that niche complexity increases with gut size and that niche selection forces dominate gut community construction.IMPORTANCEThe intestinal microbiome of animals is essential for health, contributing to digestion of foods, proper immune development, inhibition of pathogen colonization, and catabolism of xenobiotic compounds. How these communities assemble and persist is just beginning to be investigated. Here we interrogated a set of gut samples from a wide range of animals to investigate the roles of selection and random processes in microbial community construction. We show that the numbers of bacterial species increased with the weight of host organisms, paralleling findings from studies of island biogeography. Communities in larger organisms tended to be more anaerobic, suggesting one mechanism for niche diversification. Nonselective processes enable specific predictions for community structure, but our samples did not match the predictions of the neutral model. Thus, these findings highlight the importance of niche selection in community construction and suggest mechanisms of niche diversification

    Allometry and Ecology of the Bilaterian Gut Microbiome

    Get PDF
    Classical ecology provides principles for construction and function of biological communities, but to what extent these apply to the animal-associated microbiota is just beginning to be assessed. Here, we investigated the influence of several well-known ecological principles on animal-associated microbiota by characterizing gut microbial specimens from bilaterally symmetrical animals (Bilateria) ranging from flies to whales. A rigorously vetted sample set containing 265 specimens from 64 species was assembled. Bacterial lineages were characterized by 16S rRNA gene sequencing. Previously published samples were also compared, allowing analysis of over 1,098 samples in total. A restricted number of bacterial phyla was found to account for the great majority of gut colonists. Gut microbial composition was associated with host phylogeny and diet. We identified numerous gut bacterial 16S rRNA gene sequences that diverged deeply from previously studied taxa, identifying opportunities to discover new bacterial types. The number of bacterial lineages per gut sample was positively associated with animal mass, paralleling known species-area relationships from island biogeography and implicating body size as a determinant of community stability and niche complexity. Samples from larger animals harbored greater numbers of anaerobic communities, specifying a mechanism for generating more-complex microbial environments. Predictions for species/abundance relationships from models of neutral colonization did not match the data set, pointing to alternative mechanisms such as selection of specific colonists by environmental niche. Taken together, the data suggest that niche complexity increases with gut size and that niche selection forces dominate gut community construction

    Endogenous livestock development in Cameroon: Exploring the potential of local initiatives for livestock development

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    This book and accompanying film (DVD: CTA no. 1456) provide an introduction to the ELD approach to livestock development in Africa. It is the outcome of a joint effort between farmers and extension workers in Cameroon and consultants, who explored the multi-faceted role of livestock in rural communities and ways in which livestock keepers can become better informed and organised
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