6,048 research outputs found

    Mapa geológico-geomorfológico do Cabo de Santa Marta Grande, Laguna, SC, Brasil 1:15000

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    Mapa geológico e geomorfológico do Cabo de Santa Marta Grande, Laguna/SC, BrasilMapa 1:15000CAPES e CNP

    Impacts, strategies and tools to mitigate UHI

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    The impacts of climate changes to cities, which are home to over half of the world´s population, are already being felt. In many cases, the intensive speed with which urban centres have been growing means that little attention has been paid to the role played by climatic factors in maintaining the quality of life. Among the negative consequences of rapid city growth is the expansion of the problems posed by urban heat islands, defined as areas in a city that are much warmer than in other sites, especially in comparison with rural areas. This paper analyses the consistency of the UHI related literature in three stages: first it outlines its characteristics and impacts in a wide variety of cities around the world, which poses pressures to public health in many different countries. Then it introduces strategies which may be employed in order to reduce its effects, and finally, it analyses available tools to systematize the initial high-level assessment of the phenomenon for multidisciplinary teams involved in the urban planning process. The analysis of the literature on the characteristics, impacts, strategies and digital tools to assess on the UHI, reveals the wide variety of parameters, methods, tools and strategies analysed and suggested in the different studies, which does not always allow to compare or standardize the diagnosis or solutions

    Elastic properties of graphyne-based nanotubes

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    Graphyne nanotubes (GNTs) are nanostructures obtained from rolled up graphyne sheets, in the same way carbon nanotubes (CNTs) are obtained from graphene ones. Graphynes are 2D carbon-allotropes composed of atoms in sp and sp2 hybridized states. Similarly to conventional CNTs, GNTs can present different chiralities and electronic properties. Because of the acetylenic groups (triple bonds), GNTs exhibit large sidewall pores that influence their mechanical properties. In this work, we studied the mechanical response of GNTs under tensile stress using fully atomistic molecular dynamics simulations and density functional theory (DFT) calculations. Our results show that GNTs mechanical failure (fracture) occurs at larger strain values in comparison to corresponding CNTs, but paradoxically with smaller ultimate strength and Young's modulus values. This is a consequence of the combined effects of the existence of triple bonds and increased porosity/flexibility due to the presence of acetylenic groups

    Clinicopathological correlation and prognostic significance of VEGF-A, VEGF-C, VEGFR-2 and VEGFR-3 expression in colorectal cancer.

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    BACKGROUND: Colorectal cancer (CRC) is the third most common type of cancer and the fourth most frequent cause of cancer death. Literature indicates that vascular endothelial growth factor is a predominant angiogenic factor and that angiogenesis plays an important role in the progression of CRC. PATIENTS AND METHODS: The present series consisted of tissue samples obtained from 672 patients who had undergone large bowel resection between 2005 and 2010 at the Braga Hospital, Portugal. Archival paraffin-embedded CRC tissue and normal adjacent samples were used to build up tissue microarray blocks and VEGF-A, VEGF-C, VEGFR-2 and VEGFR-3 expression was immunohistochemically assessed. RESULTS: We observed an overexpression of VEGF-C in CRC when tumour cells and normal-adjacent tissue were compared (p=0.004). In tumour samples, VEGF-C-positive cases were associated with VEGFR-3 expression (p=0.047). When assessing the correlation between VEGF-A, VEGF-C, VEGFR-2 and VEGFR-3 expressions and the clinicopathological data, it was revealed that VEGF-A positive cases were associated with male gender (p=0.016) and well-differentiated tumours (p=0.001); VEGF-C with colon cancers (p=0.037), exophytic (p=0.048), moderately-differentiated (p=0.007) and T3/T4 (p=0.010) tumours; VEGFR-2 with invasive adenocarcinoma (p=0.007) and VEGFR-3 with the presence of hepatic metastasis (p=0.032). Overall survival curves for CRC were statistically significant for rectal cancer, VEGF-C expression and stage III (p=0.019) and VEGFR-3 expression and stage IV (p=0.047). CONCLUSION: Quantification of VEGF-A, VEGF-C, VEGFR-2 and VEGFR-3 expression seems to provide valuable prognostic information in CRC and the correlation with clinicopathological data revealed an association with characteristics that contribute to progression, invasion and metastasis leading to poorer survival rates and prognosis

    Plastic debris on Pacific Islands: Ecological and health implications

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    © 2019 Plastic debris is a worldwide problem. This is particularly acute in the Pacific region, where its scale is a reason for serious concerns. There is an obvious need for studies to assess the extent to which plastic debris affects the Pacific. Therefore, this research aims to address this need by undertaking a systematic assessment of the ecological and health impacts of plastic debris on Pacific islands. Using pertinent historical qualitative and quantitative data of the distribution of plastic debris in the region, this study identified pollution and contamination trends and risks to ecosystems, and suggests some measures which may be deployed to address the identified problems. The study illustrates the fact that Pacific Island States are being disproportionately affected by plastic, and reiterates that further studies and integrated strategies are needed, involving public education and empowerment, governmental action, as well as ecologically sustainable industry leadership. It is also clear that more research is needed in respect of developing alternatives to conventional plastic, by the production of bio-plastic, i.e. plastic which is produced from natural (e.g. non-fossil fuel-based sources) materials, and which can be fully biodegradable

    Using the jet stream for sustainable airship and balloon transportation of cargo and hydrogen

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    © 2019 The Author(s) The maritime shipping sector is a major contributor to CO2 emissions and this figure is expected to rise in coming decades. With the intent of reducing emissions from this sector, this research proposes the utilization of the jet stream to transport a combination of cargo and hydrogen, using airships or balloons at altitudes of 10–20 km. The jet streams flow in the mid-latitudes predominantly in a west–east direction, reaching an average wind speed of 165 km/h. Using this combination of high wind speeds and reliable direction, hydrogen-filled airships or balloons could carry hydrogen with a lower fuel requirement and shorter travel time compared to conventional shipping. Jet streams at different altitudes in the atmosphere were used to identify the most appropriate circular routes for global airship travel. Round-the-world trips would take 16 days in the Northern Hemisphere and 14 in the Southern Hemisphere. Hydrogen transport via the jet stream, due to its lower energy consumption and shorter cargo delivery time, access to cities far from the coast, could be a competitive alternative to maritime shipping and liquefied hydrogen tankers in the development of a sustainable future hydrogen economy
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