2,333 research outputs found

    Microscopy studies in support of dating of mortars of historical buildings

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    Fundação das Universidades PortuguesasMinisterio de Ciencia e InnovaciónFundação para a Ciência e a Tecnologia (FCT

    Algumas considerações sobre o estudo estatístico de medições de dose em grãos de argamassas por luminescência estimulada opticamente

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    Fundação das Universidades PortuguesasMinisterio de Ciencia e Innovación (Espanha)Fundação para a Ciência e a Tecnologia (FCT)Ação Integrada E-141”(Fundação das Universidades Portuguesas)/“Acción Integrada PT2009-0077” (Ministerio de Ciencia e Innovación)/PEst-OE/CTE/UI0697/201

    In Vivo Assessment of Natural Killer Cell Responses during Chronic Feline Immunodeficiency Virus Infection

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    Accumulating evidence suggests that natural killer (NK) cells may have an important role in HIV-1 disease pathogenesis; however, in vivo studies are lacking. Feline immunodeficiency virus (FIV) infection of cats provides a valuable model to study NK cell function in vivo. The immune response against Listeria monocytogenes (Lm) is well characterized, allowing its use as an innate immune probe. We have previously shown that locally delivered IL-15 can improve Lm clearance in FIV-infected animals, and this correlated with an increase in NK cell number. In the present study, chronically FIV-infected and SPF-control cats were challenged with Lm by unilateral subcutaneous injection next to the footpad and then treated with 5-bromo-2′-deoxyuridine (BrdU). The Lm draining and contralateral control lymph nodes were evaluated for NK, NKT, CD4+ and CD8+ T cell number, proliferation, apoptosis, and NK cell function. Listeria monocytogenes burden was also assessed in both control and Lm draining lymph nodes. NK, NKT, CD4+ T and CD8+ T cells in the Lm-challenged lymph node of FIV-infected cats did not increase in number. In addition, after Lm challenge, NK cells from FIV-infected cats did not increase their proliferation rate, apoptosis was elevated, and perforin expression was not upregulated when compared to SPF-control cats. The failure of the NK cell response against Lm challenge in the draining lymph node of FIV-infected cats correlates with the delayed control and clearance of this opportunistic bacterial pathogen

    The COVID-19 pandemic: yet another catalyst for governmental mass surveillance?

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    This commentary addresses the use of surveillance technologies in the context of the Covid-19 pandemic, using examples from the current geopolitical frame, and questioning the possible consequences of data collection for the individual and for society. In this regard, some questions emerge: in the fight against the pandemic, what measures and tools of surveillance are being adopted by the different states? Will the extraordinary measures, that are now being implemented, become permanent? And if so, what will the consequences be for privacy and democracy?info:eu-repo/semantics/publishedVersio

    Level of physical activity and body image in Portuguese and French students, 1st year of Physiotherapy

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    Adolescents have a physiological need to move, therefore physical activity should be encouraged at an early age. In young adults, there are also various physical and psychological transformations. Associated with these transformations, there is a will to fit in the patterns of society’s beauty and, sometimes, a consequent bodily dissatisfaction. Thus, it is necessary to encourage physical activity, for its benefits.info:eu-repo/semantics/publishedVersio

    Development of a four phase floating interleaved boost converter for photovoltaic systems

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    This paper explores the advantages of the Floating Interleaved Boost Converter, particularly with regards to solar photovoltaic power systems. This converter offers improved efficiency and voltage gain, while having lower input current ripple than other DC-DC boost converters. An analog linear feedback controller was developed, and adapted for discrete control. Two Maximum Power Point Tracking methods were explored, and their performances were evaluated in simulation. An experimental prototype was developed and demonstrated. The results show that this is a promising converter topology with many potential benefits for solar power applications

    Use of remote sensing to assess ecosystem integrity of the Brazilian Amazon rainforest: a Bayesian approach.

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    Biodiversity supports many ecosystem services that are very important for climate change mitigation and adaptation. There is a functional link between the tropical forest ecosystem biodiversity and their capacity for carbon uptake and storage as well as regulation of evapotranspiration flux. Nevertheless, land use changes and agriculture expansion reduce the ecosystems integrity modifying the functions related directly to the ecosystem services. The relationship between biodiversity loss and the impacts on ecosystem services of tropical forests, in face of the ongoing global climate change needs to be better quantified. In this work, we considered the concept of Ecosystem Integrity (EI), which represents the connection of biodiversity with the ability of ecosystems to sustain the processes of self-organization. Bayesian Networks (BBN-Bayesian Belief Network) can provide metrics for the generation of Ecosystem Integrity Index, from the training of probabilistic relationships of evidence obtained through Remote Sensing data. The objective of this work is to present the methodological approach and the results of EI mapping, elaborated at the regional scale for different patterns of phyto-ecologic landscape of the Brazilian Amazon. The modelling was based on learning from the parameters (data-driven model) through the use of the Expectation Maximization algorithm. For the validation of this probabilistic model, an evaluation was carried out in controlled areas with field observation by experts. Results showed that it is possible to generate an Ecosystem Integrity Index at regional scale using a probabilistic model based on Bayesian Belief Networks (BBN), and totally free web-available satellite products

    A remote sensing approach for regional-scale mapping of agricultural land-use systems based on NDVI time series.

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    In response to the need for generic remote sensing tools to support large-scale agricultural monitoring, we present a new approach for regional-scale mapping of agricultural land-use systems (ALUS) based on object-based Normalized Difference Vegetation Index (NDVI) time series analysis. The approach consists of two main steps. First, to obtain relatively homogeneous land units in terms of phenological patterns, a principal component analysis (PCA) is applied to an annual MODIS NDVI time series, and an automatic segmentation is performed on the resulting high-order principal component images. Second, the resulting land units are classified into the crop agriculture domain or the livestock domain based on their land-cover characteristics. The crop agriculture domain land units are further classified into different cropping systems based on the correspondence of their NDVI temporal profiles with the phenological patterns associated with the cropping systems of the study area. A map of the main ALUS of the Brazilian state of Tocantins was produced for the 2013-2014 growing season with the new approach, and a significant coherence was observed between the spatial distribution of the cropping systems in the final ALUS map and in a reference map extracted from the official agricultural statistics of the Brazilian Institute of Geography and Statistics (IBGE). This study shows the potential of remote sensing techniques to provide valuable baseline spatial information for supporting agricultural monitoring and for large-scale land-use systems analysis
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