723 research outputs found

    Modelagem conceitual de banco de dados geográfico aplicado ao sistema de dados georreferenciados para os campos experimentais da Embrapa Tabuleiros Costeiros.

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    A Embrapa Tabuleiros Costeiros diante da necessidade de utilizar uma ferramenta que auxilie o planejamento espacial dos campos experimentais, e tendo em vista as diversas possibilidades de mapeamento, associações, conexões e visualização dinâmica proporcionadas pelos Sistemas de Informações Geográficas (SIGs), iniciou o desenvolvimento de um projeto de SIG a ser disponibilizado pela internet (WebGis). Dentre as etapas do projeto está a modelagem conceitual de Banco de Dados Geográficos (BDG), considerada entre as principais atividades que contribuem para o sucesso de um SIG. Essa técnica auxilia tanto os desenvolvedores quanto aos usuários na definição e entendimento do escopo, da estrutura e do comportamento desejado do sistema, garantindo assim que as funcionalidades e informações disponibilizadas atenderão as necessidades do público-alvo do projeto. Nessa perspectiva, esse trabalho apresenta o modelo conceitual inicial do Sistema de Dados Geográficos dos Campos Experimentais, elaborado em conformidade com o ML-Geo-Frame e implementado no ArgoCaseGeo

    A New Technique for Reachability of States in Concatenation Automata

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    We present a new technique for demonstrating the reachability of states in deterministic finite automata representing the concatenation of two languages. Such demonstrations are a necessary step in establishing the state complexity of the concatenation of two languages, and thus in establishing the state complexity of concatenation as an operation. Typically, ad-hoc induction arguments are used to show particular states are reachable in concatenation automata. We prove some results that seem to capture the essence of many of these induction arguments. Using these results, reachability proofs in concatenation automata can often be done more simply and without using induction directly.Comment: 23 pages, 1 table. Added missing affiliation/funding informatio

    Pervasive Phylogenomic Incongruence Underlies Evolutionary Relationships in Eyebrights (Euphrasia, Orobanchaceae)

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    Disentangling the phylogenetic relationships of taxonomically complex plant groups is often mired by challenges associated with recent speciation, hybridization, complex mating systems, and polyploidy. Here, we perform a phylogenomic analysis of eyebrights (Euphrasia), a group renowned for taxonomic complexity, with the aim of documenting the extent of phylogenetic discordance at both deep and at shallow phylogenetic scales. We generate whole-genome sequencing data and integrate this with prior genomic data to perform a comprehensive analysis of nuclear genomic, nuclear ribosomal (nrDNA), and complete plastid genomes from 57 individuals representing 36 Euphrasia species. The species tree analysis of 3,454 conserved nuclear scaffolds (46 Mb) reveals that at shallow phylogenetic scales postglacial colonization of North Western Europe occurred in multiple waves from discrete source populations, with most species not being monophyletic, and instead combining genomic variants from across clades. At a deeper phylogenetic scale, the Euphrasia phylogeny is structured by geography and ploidy, and partially by taxonomy. Comparative analyses show Southern Hemisphere tetraploids include a distinct subgenome indicative of independent polyploidy events from Northern Hemisphere taxa. In contrast to the nuclear genome analyses, the plastid genome phylogeny reveals limited geographic structure, while the nrDNA phylogeny is informative of some geographic and taxonomic affinities but more thorough phylogenetic inference is impeded by the retention of ancestral polymorphisms in the polyploids. Overall our results reveal extensive phylogenetic discordance at both deeper and shallower nodes, with broad-scale geographic structure of genomic variation but a lack of definitive taxonomic signal. This suggests that Euphrasia species either have polytopic origins or are maintained by narrow genomic regions in the face of extensive homogenizing gene flow. Moreover, these results suggest genome skimming will not be an effective extended barcode to identify species in groups such as Euphrasia, or many other postglacial species groups

    Computing welfare losses from data under imperfect competition with heterogeneous goods

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    We study the percentage of welfare losses (PWL) yielded by imperfect competition under product differentiation. When demand is linear, if prices, outputs, costs and the number of firms can be observed, PWL is arbitrary in both Cournot and Bertrand equilibria. If in addition, the elasticity of demand (resp. cross elasticity of demand) is known, we can calculate PWL in Cournot (resp. Bertrand) equilibrium. When demand is isoelastic and there are many firms, PWL can be computed from prices, outputs, costs and the number of .rms. In all these cases we find that price-marginal cost margins and demand elasticities may influence PWL in a counterintuitive way. We also provide conditions under which PWL increases or decreases with concentration

    The master builders: LAIRAH research on good practice in the construction of digital humanities projects

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    Although many digital humanities resources are being developed for online use, there is little understanding of why some become popular, whilst others are neglected. Through log analysis techniques, the LAIRAH project identified twenty-one popular and well-used digital humanities projects, and in order to ascertain the factors they had in common, which predisposed them to be well used, conducted in-depth interviews with the creators of these resources. This article presents the findings of the study, highlighting areas that developers should be aware of, and providing a set of recommendations for both funders and creators, which should ensure that a digital humanities resource will have the best possible chance of being used in the long term

    Tropomyosin Promotes Lamellipodial Persistence by Collaborating with Arp2/3 at the Leading Edge

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    At the leading edge of migrating cells, protrusion of the lamellipodium is driven by Arp2/3-mediated polymerization of actin filaments [1]. This dense, branched actin network is promoted and stabilized by cortactin [2, 3]. In order to drive filament turnover, Arp2/3 networks are remodeled by proteins such as GMF, which blocks the actin-Arp2/3 interaction [4, 5], and coronin 1B, which acts by directing SSH1L to the lamellipodium where it activates the actin-severing protein cofilin [6, 7]. It has been shown in vitro that cofilin-mediated severing of Arp2/3 actin networks results in the generation of new pointed ends to which the actin-stabilizing protein tropomyosin (Tpm) can bind [8]. The presence of Tpm in lamellipodia, however, is disputed in the literature [9-19]. Here, we report that the Tpm isoforms 1.8/9 are enriched in the lamellipodium of fibroblasts as detected with a novel isoform-specific monoclonal antibody. RNAi-mediated silencing of Tpm1.8/9 led to an increase of Arp2/3 accumulation at the cell periphery and a decrease in the persistence of lamellipodia and cell motility, a phenotype consistent with cortactin- and coronin 1B-deficient cells [2, 7]. In the absence of coronin 1B or cofilin, Tpm1.8/9 protein levels are reduced while, conversely, inhibition of Arp2/3 with CK666 leads to an increase in Tpm1.8/9 protein. These findings establish a novel regulatory mechanism within the lamellipodium whereby Tpm collaborates with Arp2/3 to promote lamellipodial-based cell migration

    Innovative Technics of Managing Engineers' Global Competencies

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    Higher education modernization in the CIS countries takes place under the conditions of dynamic changes in economy and society. These changes are determined by the social and economic development of the country and the world globalization processes - cross-border intercultural communication, knowledge transparency, and the establishment of information society. Educational globalization is a continuous process of creating a unified global educational system, in which the distinctions between its member educational systems are being blended

    Thermostability of cardosin A from Cynara cardunculus L.

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    The structural stability of cardosin A, a plant aspartic proteinase (AP) from Cynara cardunculus L., has been investigated by high-sensitivity differential scanning calorimetry, intrinsic fluorescence and circular dichroism spectroscopy, and enzymatic activity assays. Even though the thermal denaturation of cardosin A is partially irreversible, valid thermodynamic data can be obtained within a wide pH region. Also, although cardosin A is a heterodimeric enzyme its thermal denaturation occurs without simultaneous dissociation to unfolded monomers. Moreover, in the 3-7 pH region the excess heat capacity can be deconvoluted into two components corresponding to two elementary two-state transitions, suggesting that the two polypeptide chains of cardosin A unfold independently. Detailed thermodynamic and structural investigations of cardosin A at pH=5.0, at which value the enzyme demonstrates maximum stability and enzymatic activity, revealed that after thermal denaturation the polypeptide chains of this protein retain most of their secondary structure motifs and are not completely hydrated.http://www.sciencedirect.com/science/article/B6THV-47P1SF6-4/1/edc14f851e47459fcd87b748d068439
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