996 research outputs found

    VCube-PS: A Causal Broadcast Topic-based Publish/Subscribe System

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    In this work we present VCube-PS, a topic-based Publish/Subscribe system built on the top of a virtual hypercube-like topology. Membership information and published messages are broadcast to subscribers (members) of a topic group over dynamically built spanning trees rooted at the publisher. For a given topic, the delivery of published messages respects the causal order. VCube-PS was implemented on the PeerSim simulator, and experiments are reported including a comparison with the traditional Publish/Subscribe approach that employs a single rooted static spanning-tree for message distribution. Results confirm the efficiency of VCube-PS in terms of scalability, latency, number and size of messages.Comment: Improved text and performance evaluation. Added proof for the algorithms (Section 3.4

    The Yellow-­crowned Night Heron Nyctanassa violacea (Aves: Pelecaniformes: Ardeidae) in the Azores and Madeira Archipelagos: a new species for the Western Palearctic

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    This paper presents and describes the first confirmed occurrence of the Yellow-crowned Night Heron Nyctanassa violacea in the Azores, which also represents the first record for Europe and the Western Palearctic. We also present and discuss subsequent reports of the species in Macaronesia. Several hypotheses may help to explain the occurrence of this species in this part of the Atlantic, including disorientation caused by strong winds and increasing observation pressure. However, further studies are necessary to assess the part played by the different factors in the occurrence of new vagrant individuals/species in Macaronesia

    On the design and development of emulation platforms for NFV-based infrastructures

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    Network Functions Virtualisation (NFV) presents several advantages over traditional network architectures, such as flexibility, security, and reduced CAPEX/OPEX. In traditional middleboxes, network functions are usually executed on specialised hardware (e.g., firewall, DPI). Virtual Network Functions (VNFs) on the other hand, are executed on commodity hardware, employing Software Defined Networking (SDN) technologies (e.g., OpenFlow, P4). Although platforms for prototyping NFV environments have emerged in recent years, they still present limitations that hinder the evaluation of NFV scenarios such as fog computing and heterogeneous networks. In this work, we present NIEP: a platform for designing and testing NFV-based infrastructures and VNFs. NIEP consists of a network emulator and a platform for Click-based VNFs development. NIEP provides a complete NFV emulation environment, allowing network operators to test their solutions in a controlled scenario prior to deployment in production networks

    A comparative study of the occurence of anthracnose (Colletotrichum gloeosporioides) in cultivars of pepper (Piper nigrum L.) recently introduced in Porto Velho, state of Rondonia.

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    In an experiment carried out in an experimental area of EMBRAPA (Brazilian Agriculture Research Enterprise) UEPAE (Unit for Execution of Research) of Porto Velho, State of Rondonia, Brazil, located at km 5.5 of the BR-364 Highway, latitude 8°46'5"S, longitude 63°5' Greenwich and altitude 96.3m above sea level, evaluations were made of both the occurence of anthracnose caused by the fungus (Colletotrichum goeosporioides) in 5 cultivars of pepper (Piper nigrum L.) at the time of the first yield, 18 months after planting and of the leaves, correlating them with productivity of the cultivars. The results obtained led to the following conclusions: the cultivar Guajarina showed to be less susceptible to anthracnose and more resistant to fall of the leaves; the cultivars Bragantina, Cingapura and Djambi behaved similarly as to fall of the leaves; the cultivars Bragantina and Cingapura had the same behavior and were less susceptible to anthracnose when compared with cultivars Djambi and Belantung, while the cultivars Belantung showed to be more susceptible to anthracnose and less resistant to fall of the leaves.Em um experimento conduzido em årea experimental da EMBRAPA, UEPAE de Porto Velho, Rondônia, localizado no km 5,5 da BR-364, com latitude sul 8º46'5", longitude 63°5' de Greenwich e altitude de 96,3 metros acima do nível do mar, avaliou - se em 5 cultivares de Pimenta - do - reino (Piper nigrum L.), por ocasião da primeira produção, 18 meses após plantio, a incidência da doença antracnose provocada pelo fungo Colletotrichum gloeosporioides e a porcentagem de desfolha das plantas, correlacionando-as com a produtividade dos cultivares. Os resultados obtidos permitiram concluir que: o cultivar Guajarina mostrou ser menos susceptível a antracnose e mais resistente a desfolha; os cultivares Bragantina, Cingapura e Djambi comportaram-se de maneira semelhante com relação a desfolha; os cultivares Bragantina e Cingapura, foram iguais entre si e menos susceptíveis com relação a antracnose quando comparados com os cultivares Djambi e Belantung, enquanto que o cultivar Belantung mostrou ser mais susceptível à antracnose e menos resistente a desfolha

    AnĂĄlise crĂ­tica do processo administrativo proposto por Fayol e o modelo da cadeia de valor proposto por Michael Porter

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     Foi realizada uma anålise crítica do processo administrativo proposto por Fayol e o modelo da cadeia de valor proposto por Michael Porter, analisando o período em que cada um viveu e implantou as suas teorias, conseguimos observar o que hå em comum entre eles e as suas principais divergências. Para a realização da pesquisa foi utilizado o acervo da biblioteca do UniFOA. Descrevemos a metodologia do Fayol e a metodologia da cadeia de valor. Analisamos o estado da arte em seus momentos históricos, Fayol viveu no SÊculo XIX enquanto Porter pertence ao SÊculo XXI. Apesar de Êpocas bem distintas, tanto Fayol quanto Porter visavam o gerenciamento, organizando as atividades em grau de importância. Fayol utilizou mÊtodos científicos para definir alguns princípios que influenciaram na função do chefe. E Porter adaptou os conceitos de Fayol para os desafios vividos no seu período. Alguns princípios de Fayol estão ultrapassados para a Êpoca de Porter como, por exemplo: divisão do trabalho; autoridade; unidade de comando; centralização que na Êpoca de Fayol eram requisitos essenciais para o chefe, jå com Porter a preocupação Ê formar equipes independentes, participativas e produtivas, com foco direto no cliente. O objetivo do trabalho foi analisar mÊtodos de administração, identificar princípios essenciais para a função de gestor e tambÊm identificar princípios que foram adaptados para o período atual devido a fatores como, por exemplo, a globalização

    Theoretical and experimental study of the excitonic binding energy\ud in GaAs/AlGaAs single and coupled double quantum wells

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    This paper discusses the theoretical and experimental results obtained for the excitonic binding energy (Eb) in a set of single and coupled double quantum wells (SQWs and CDQWs) of GaAs/AlGaAs with different Al concentrations (Al%) and inter-well barrier thicknesses. To obtain the theoretical Eb the method proposed by Mathieu, Lefebvre and Christol (MLC) was used, which is based on the idea of fractional-dimension space, together with the approach proposed by Zhao et al., which extends the MLC method for application in CDQWs. Through magnetophotoluminescence (MPL) measurements performed at 4 K with magnetic fields ranging from 0 T to 12 T, the diamagnetic shift curves were plotted and adjusted using two expressions: one appropriate to fit the curve in the range of low intensity fields and another for the range of high intensity fields, providing the experimental Eb values. The effects of increasing the Al% and the inter-well barrier thickness on Eb are discussed. The Eb reduction when going from the SQW to the CDQW with 5 Å inter-well barrier is clearly observed experimentally for 35% Al concentration and this trend can be noticed even for concentrations as low as 25% and 15%, although the Eb variations in these latter cases are within the error bars. As the Zhao's approach is unable to describe this effect, the wave functions and the probability densities for electrons and holes were calculated, allowing us to explain this effect as being due to a decrease in the spatial superposition of the wave functions caused by the thin inter-well barrier.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná (Fundação Araucária)Fundo de Apoio ao Ensino, à Pesquisa e à Extensão (FAPE-UEL)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Instituto Nacional de Ciência e Tecnologia de Nanodispositivos Semicondutores, Brazil

    Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

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    Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

    Performance and Operation of the CMS Electromagnetic Calorimeter

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    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented
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