209 research outputs found

    The inherent instability of leveed seafloor channels

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    New analytical models demonstrate that under 2 aggradational flow conditions seafloor channel-levee systems are inherently unstable; both channel area and stability necessarily decrease at long timescales. In time such systems must avulse purely through internal (autogenic) forcing. Although autogenic instabilities likely arise over long enough time for additional allogenic forcing to be expected, channel-levee sensitivity to variations in flow character depends on the prior degree of system evolution. Recalibrated modern Amazon Fan avulsion timings are consistent with this model, challenging accepted interpretations of avulsion triggering

    Exploiting web technologies to build autonomic wireless sensor networks

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    Most of the current wireless sensor networks are built for specific applications, with a tight coupling between them and the underlying communication protocols. We present a more flexible architectural approach for building WSNs, in which application-specific features are decoupled from the underlying communication infrastructure, although affecting the network behavior. We propose a framework based on Web technologies that provides a standard interface for accessing the network and configurable service components tailored to meet different application requirements, while optimizing the network scarce resources. Also, a set of ontologies is defined as part of the framework for representing shared knowledge of the WSN domain.8th IFIP/IEEE International conference on Mobile and Wireless CommunicationRed de Universidades con Carreras en Informática (RedUNCI

    SATYA: A Reputation-based Approach for Service Discovery and Selection in Service Oriented Architectures

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    ABSTRACT We present SATYA, a system that computes a reputation value for Web service providers in order to enhance the service discovery and selection process increasing reliability in SOA transactions. In this work, objective values of service evaluations supplied by monitoring entities are used along with subjective evaluations supplied by service consumers. The objective and subjective values are compared in order to: (i) validate subjective evaluations; (ii) minimize the degree of subjectivity of computed reputation values; and (iii) discover consumers' preferences in terms of QoS metrics. By assigning Web services a trustable reputation value, SATYA enhances the service descriptions provided by registries with additional information to be used during the service discovery phase

    Exploiting web technologies to build autonomic wireless sensor networks

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    Most of the current wireless sensor networks are built for specific applications, with a tight coupling between them and the underlying communication protocols. We present a more flexible architectural approach for building WSNs, in which application-specific features are decoupled from the underlying communication infrastructure, although affecting the network behavior. We propose a framework based on Web technologies that provides a standard interface for accessing the network and configurable service components tailored to meet different application requirements, while optimizing the network scarce resources. Also, a set of ontologies is defined as part of the framework for representing shared knowledge of the WSN domain.8th IFIP/IEEE International conference on Mobile and Wireless CommunicationRed de Universidades con Carreras en Informática (RedUNCI

    Paleoparasitology: Perspectives with New Techniques

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    Paleoparasitology is the study of parasites found in archaeological material. The development of this field of research began with histological identification of helminth eggs in mummy tissues, analysis of coprolites, and recently through molecular biology. An approach to the history of paleoparasitology is reviewed in this paper, with special reference to the studies of ancient DNA identified in archaeological material. Paleoparasitologia: perspectivas com novas técnicas Paleoparasitologia é o estudo de parasitos encontrados em material arqueológico. O desenvolvimento deste campo da pesquisa teve início com a identificação de ovos de helmintos em tecidos mumificados, análise de coprólitos e, recentemente, através da biologia molecular. Neste artigo faz-se uma breve revisão da história da paleoparasitologia com referência especial aos estudos de ADN antigo (ancient DNA) em material arqueológic

    Cell populations in lesions of cutaneous leishmaniasis of leishmania (L.) amazonensis- infected rhesus macaques, Macaca mulatta

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    The cellular nature of the infiltrate in cutaneous lesion of rhesus monkeys experimentally infected with Leishmania (L.) amazonensis was characterized by immunohistochemistry. Skin biopsies from infected animals with active or healing lesions were compared to non-infected controls (three of each type) to quantitate inflammatory cell types. Inflammatory cells (composed of a mixture of T lymphocyte subpopulations, macrophages and a small number of natural killer cells and granulocytes) were more numerous in active lesions than in healing ones. T-cells accounted for 44.7 ± 13.1% of the infiltrate in active lesions (versus CD2+= 40.3 ± 5.7% in healing lesions) and T-cell ratios favor CD8+ cells in both lesion types. The percentage of cells expressing class II antigen (HLA-DR+) in active lesions (95 ± 7.1%) was significantly higher (P < 0.005) from the healing lesions (42.7 ± 12.7%). Moreover, the expression of the activation molecules CD25 (@ 16%), the receptor for interleukin-2, suggests that many T cells are primed and proliferating in active lesions. Distinct histopathological patterns were observed in lesions at biopsy, but healing lesions contained more organized epithelioid granulomas and activated macrophages, followed by fibrotic substitution. The progression and resolution of skin lesions appears to be very similar to that observed in humans, confirming the potential for this to be used as a viable model to study the immune response in human cutaneous leishmaniasis

    Paleoparasitology: Perspectives with New Techniques

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    Paleoparasitology is the study of parasites found in archaeological material. The development of this field of research began with histological identification of helminth eggs in mummy tissues, analysis of coprolites, and recently through molecular biology. An approach to the history of paleoparasitology is reviewed in this paper, with special reference to the studies of ancient DNA identified in archaeological material. Paleoparasitologia: perspectivas com novas técnicas Paleoparasitologia é o estudo de parasitos encontrados em material arqueológico. O desenvolvimento deste campo da pesquisa teve início com a identificação de ovos de helmintos em tecidos mumificados, análise de coprólitos e, recentemente, através da biologia molecular. Neste artigo faz-se uma breve revisão da história da paleoparasitologia com referência especial aos estudos de ADN antigo (ancient DNA) em material arqueológic

    Middleware orientado a serviços para redes de sensores sem fio

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    There is a wide range of applications for wireless sensor networks (WSNs) with different needs. The WSN infrastructure and protocols change according to the application needs. To achieve the best performance of the WSN, its operation should be adapted to the application needs. We propose a middleware for WSNs that provides a layer between applications and the network. The middleware offers a standard mechanism for representing user queries, sensor tasks and data. It also provides an automatic choice of the best network configuration and data dissemination strategy. Users are able to access the WSN without worrying about the underlying infrastructure and software. From the WSN perspective, the system provides the best match between communication protocols and application requirements.Há uma ampla gama de aplicações para redes de sensores sem fio (RSSF)s, com diferentes necessidades. A infraestrutura e o protocolo de disseminação de dados da rede variam de acordo com a aplicação. Para o melhor desempenho quanto ao consumo de energia e à qualidade do serviço fornecido pela rede, seu funcionamento deve ser adaptado às necessidades da aplicação. Este trabalho propõe um middleware que oferece uma camada entre aplicações e a rede de sensores e oferece um mecanismo padrão para representar consultas, tarefas e dados. Além disso, fornece a escolha automatizada da configuração da rede e da estratégia de disseminação de dados usada, permitindo ao usuário acessar a rede sem tomar conhecimento de infraestrutura e software subjacentes. Do ponto de vista da rede, o sistema visa obter a melhor combinação entre protocolos de comunicação e requisitos da aplicação

    Local Chatter or International Buzz? Language Differences on Posts about Zika Research on Twitter and Facebook

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    Background When the Zika virus outbreak became a global health emergency in early 2016, the scientific community responded with an increased output of Zika-related research. This upsurge in research naturally made its way into academic journals along with editorials, news, and reports. However, it is not yet known how or whether these scholarly communications were distributed to the populations most affected by Zika. Methodology/Principal findings To understand how scientific outputs about Zika reached global and local audiences, we collected Tweets and Facebook posts that linked to Zika-related research in the first six months of 2016. Using a language detection algorithm, we found that up to 90% of Twitter and 76% of Facebook posts are in English. However, when none of the authors of the scholarly article are from English-speaking countries, posts on both social media are less likely to be in English. The effect is most pronounced on Facebook, where the likelihood of posting in English is between 11 and 16% lower when none of the authors are from English-speaking countries, as compared to when some or all are. Similarly, posts about papers written with a Brazilian author are 13% more likely to be in Portuguese on Facebook than when made on Twitter. Conclusions/Significance Our main conclusion is that scholarly communication on Twitter and Facebook of Zikarelated research is dominated by English, despite Brazil being the epicenter of the Zika epidemic. This result suggests that scholarly findings about the Zika virus are unlikely to be distributed directly to relevant populations through these popular online mediums. Nevertheless, there are differences between platforms. Compared to Twitter, scholarly communication on Facebook is more likely to be in the language of an author’s country. The Zika outbreak provides a useful case-study for understanding how scientific outputs are communicated to relevant populations. Our results suggest that Facebook is a more effective channel than Twitter, if communication is desired to be in the native language of the affected country. Further research should explore how local media—such as governmental websites, newspapers and magazines, as well as television and radio—disseminate scholarly publication
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