4,674 research outputs found

    Publishing Marine Geospatial Data on the Web: the DFO GeoBrowser

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    In response to a need to integrate geospatial data from multiple locations and products, the Department of Fisheries and Oceans developed the DFO GeoPortal as a suite of standards-based geospatial services and applications. While initially implemented to support internal operations and decision-making processes, the GeoPortal was extended to support public access through the development of a new component, the GeoBrowser. This paper provides an overview of the GeoBrowser, its contents, evolution from the internal DFO GeoPortal intranet Web mapping services and shows how DFO is using it to help other stakeholders to make their data available through the Web.En respuesta a una necesidad de integrar datos geoespaciales procedentes de mûltiples lugares y productos, el Departamento de Pesquerias y de los Océanos desarrollô el GeoPortal DFO como una serie de servicios y aplicaciones basados en las normas. Aunque fue implementado inicialmente para apoyar las operaciones internas y los procesos de toma de decisiones, el GeoPortal fue ampliado para apoyar el acceso publico mediante el desarrollo de un nuevo componente, el GeoBrowser. Este artîculo proporciona una vision de conjunto del GeoBrowser, su contenido, su evoluciôn a partir de los servicios cartogrâficos del Intranet del GeoPortal DFO y muestra cômo esté usândolo el DFO para ayudar a otras partes asociadas a hacer que sus datos estén disponibles gracias al Web.En réponse à la nécessité d ’intégrer des données géospatiales d ’endroits et de produits multiples, le «Department o f Fisheries and Oceans (DFO)» a développé le GeoPortal en tant qu'ensemble de services et d'applications géospatiaux reposant sur des normes. Bien qu'initialement mis en oeuvre afin de soutenir les opérations internes et les processus de prise de décision, le GeoPortal a été élargi en faveur d ’un accès public grâce au développement d'une nouvelle composante: le GeoBrowser. Cet article donne une vue d'ensemble du GeoBrowser, de son contenu, et de son évolution à partir des services de cartographie Web intranet du GeoPortal DFO interne, et montre comment le DFO l'utilise pour aider d ’autres parties prenantes à mettre leur données à disposition sur le Web

    Hydrographic Data Standards and Standards-based Geospatial Data Infrastructures

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    The global leadership shown by the International Hydrographic Organization (IHO) in leading the development and implementation of international standards for the paper navigational chart has been successfully carried over into the digital domain. This has been demonstrated by the acceptance and use of the S57 and S52 data standards for Electronic Navigational Charts (ENCs). The IHO has also been careful to ensure that S57 and S52 retain upward compatibility with other emerging international standards for geospatial data. The first part of the paper reviews the position and status of S57 in re lation to this new standards environment. The second part of the paper considers the influence of the Internet which is having a major influence on the emerging geospatial data infrastructures that are being built in a number of countries and impacting the distribution and use of geospatial data, and will also provide opportunities for, and have an effect on the provision of data by hydrographic offices

    Integrin/Fak/Src-mediated regulation of cell survival and anoikis in human intestinal epithelial crypt cells: selective engagement and roles of PI3-K isoform complexes

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    In human intestinal epithelial crypt (HIEC) cells, the PI3-K/Akt-1 pathway is crucial for the promotion of cell survival and suppression of anoikis. Class I PI3-K consists of a complex formed by a catalytic (C) and regulatory (R) subunit. Three R (p85α, β, and p55γ) and four C (p110α, β, γ and δ) isoforms are known. Herein, we analyzed the expression of PI3-K isoforms in HIEC cells and determined their roles in cell survival, as well as in the β1 integrin/Fak/Src-mediated suppression of anoikis. We report that: (1) the predominant PI3-K complexes expressed by HIEC cells are p110α/p85β and p110α/p55γ; (2) the inhibition and/or siRNA-mediated expression silencing of p110α, but not that of p110β, γ or δ, results in Akt-1 down-activation and consequent apoptosis; (3) the expression silencing of p85β or p55γ, but not that of p85α, likewise induces Akt-1 down-activation and apoptosis; however, the impact of a loss of p55γ on both Akt-1 activation and cell survival is significantly greater than that from the loss of p85β; and (4) both the p110α/p85β and p110α/p55γ complexes are engaged by β1 integrin/Fak/Src signaling; however, the engagement of p110α/p85β is primarily Src-dependent, whereas that of p110α/p55γ is primarily Fak-dependent (but Src-independent). Hence, HIEC cells selectively express PI3-K isoform complexes, translating into distinct roles in Akt-1 activation and cell survival, as well as in a selective engagement by Fak and/or Src within the context of β1 integrin/Fak/Src-mediated suppression of anoikis

    Summer CO2 evasion from streams and rivers in the Kolyma River basin, north-east Siberia

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    Inland water systems are generally supersaturated in carbon dioxide (CO2) and are increasingly recognized as playing an important role in the global carbon cycle. The Arctic may be particularly important in this respect, given the abundance of inland waters and carbon contained in Arctic soils; however, a lack of trace gas measurements from small streams in the Arctic currently limits this understanding.We investigated the spatial variability of CO2 evasion during the summer low-flow period from streams and rivers in the northern portion of the Kolyma River basin in north-eastern Siberia. To this end, partial pressure of carbon dioxide (pCO2) and gas exchange velocities (k) were measured at a diverse set of streams and rivers to calculate CO2 evasion fluxes. We combined these CO2 evasion estimates with satellite remote sensing and geographic information system techniques to calculate total areal CO2 emissions. Our results show that small streams are substantial sources of atmospheric CO2 owing to high pCO2 and k, despite being a small portion of total inland water surface area. In contrast, large rivers were generally near equilibrium with atmospheric CO2. Extrapolating our findings across the Panteleikha-Ambolikha sub-watersheds demonstrated that small streams play a major role in CO2 evasion, accounting for 86% of the total summer CO2 emissions from inland waters within these two sub-watersheds. Further expansion of these regional CO2 emission estimates across time and space will be critical to accurately quantify and understand the role of Arctic streams and rivers in the global carbon budget

    The Influence of Surface Roughness on Nucleate Pool Boiling Heat Transfer

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    The effect of surface roughness on pool boiling heat transfer is experimentally explored over a wide range of roughness values in water and Fluorinert™ FC-77, two fluids with different thermal properties and wetting characteristics. The test surfaces ranged from a polished surface (Ra between 0.027 micrometer and 0.038 micrometer) to electrical discharge machined (EDM) surfaces with a roughness Ra ranging from 1.08 micrometer to 10.0 micrometer. Different trends were observed in the heat transfer coefficient with respect to the surface roughness between the two fluids on the same set of surfaces. For FC-77, the heat transfer coefficient was found to continually increase with increasing roughness. For water, on the other hand, EDM surfaces of intermediate roughness displayed similar heat transfer coefficients that were higher than for the polished surface, while the roughest surface showed the highest heat transfer coefficients. The heat transfer coefficients were more strongly influenced by surface roughness with FC-77 than with water. For FC-77, the roughest surface produced 210% higher heat transfer coefficients than the polished surface while for water, a more modest 100% enhancement was measured between the same set of surfaces. Although the results highlight the inadequacy of characterizing nucleate pool boiling data using Ra, the observed effect of roughness was correlated using hRa m as has been done in several prior studies. The experimental results were compared with predictions from several widely used correlations in the literature
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