1,544 research outputs found

    Angular Momentum of the BTZ Black Hole in the Teleparallel Geometry

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    We carry out the Hamiltonian formulation of the three- dimensional gravitational teleparallelism without imposing the time gauge condition, by rigorously performing the Legendre transform. Definition of the gravitational angular momentum arises by suitably interpreting the integral form of the constraint equation Gama^ik=0 as an angular momentum equation. The gravitational angular momentum is evaluated for the gravitational field of a rotating BTZ black hole.Comment: 17 pages, no figures, v2: some misprints corrected, Ref.s added, Eq.s revised, submitted to General Relativity and Gravitatio

    Macroclimate Determines the Global Range Limit of Aedes aegypti

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    Aedes aegypti is the main vector of dengue and a number of other diseases worldwide. Because of the domestic nature of this mosquito, the relative importance of macroclimate in shaping its distribution has been a controversial issue. We have captured here the worldwide macroclimatic conditions occupied by A. aegypti in the last century. We assessed the ability of this information to predict the species' observed distribution using supra-continental spatially-uncorrelated data. We further projected the distribution of the colonized climates in the near future (2010-2039) under two climate-change scenarios. Our results indicate that the macroclimate is largely responsible for setting the maximum range limit of A. aegypti worldwide and that in the near future, relatively wide areas beyond this limit will receive macroclimates previously occupied by the species. By comparing our projections, with those from a previous model based strictly on species-climate relationships (i.e., excluding human influence), we also found support for the hypothesis that much of the species' range in temperate and subtropical regions is being sustained by artificial environments. Altogether, these findings suggest that, if the domestic environments commonly exploited by this species are available in the newly suitable areas, its distribution may expand considerably in the near future.info:eu-repo/semantics/publishedVersio

    Anestesia no Século XIX e XX e os Hospitais da Universidade de Coimbra

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    Assessing the current and future suitability to the Asian Tiger mosquito, a dengue and Zika vector, in major cities in Europe

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    The Asian Tiger mosquito is already established in many countries in Europe and cities are particularly vulnerable to the spread of vector-borne diseases. We evaluated the suitability of 62 large urban areas in Europe to the establishment of the mosquito, based on the level of agreement between published modelling results that estimated the spatial distribution of the Aedes albopictus. We classified suitability and uncertainty levels according to the number of matching models on a 25 km cell basis and retrieved the predominant class within the boundaries of each urban area. We analysed 7 models for current conditions and 5 for future conditions (2050-2080), as well as changes in classes between these two timeframes. Currently, 60% of the cities are suitable to the mosquito, 8% are unsuitable and 32% show high uncertainty. In the future, 87% will be suitable and none will be unsuitable, including cities in the British Isles and Scandinavia, which will have to adapt their public health policies.info:eu-repo/semantics/publishedVersio

    Assessing present and future suitability of major European cities to the Asian Tiger mosquito, a vector of dengue and Zika

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    The Asian Tiger mosquito (Aedes albopictus) is already established in many countries of Europe and cities are particularly vulnerable to the spread of vector-borne diseases. We evaluated the suitability of 62 large urban areas in Europe to the establishment of this mosquito, based on the level of agreement between published predictions of its potential distribution. We classified levels of suitability and uncertainty according to the number of matching models at a 25 km cell size and retrieved the predominant class within the boundaries of each urban area. We analysed 7 independent predictions for current conditions and 5 for future conditions (2050-2080), as well as changes in classes between the two timeframes. Currently, 60% of the cities are suitable to the mosquito, 8% are unsuitable and 32% show high uncertainty. In the future, 87% will be suitable and none will be unsuitable, including cities in the British Isles and Scandinavia, which will have to adapt their public health policies.info:eu-repo/semantics/publishedVersio

    Wide and increasing suitability for Aedes albopictus in Europe is congruent across distribution models

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    The Asian tiger mosquito (Aedes albopictus), a vector of dengue, Zika and other diseases, was introduced in Europe in the 1970s, where it is still widening its range. Spurred by public health concerns, several studies have delivered predictions of the current and future distribution of the species for this region, often with differing results. We provide the first joint analysis of these predictions, to identify consensus hotspots of high and low suitability, as well as areas with high uncertainty. The analysis focused on current and future climate conditions and was carried out for the whole of Europe and for 65 major urban areas. High consensus on current suitability was found for the northwest of the Iberian Peninsula, southern France, Italy and the coastline between the western Balkans and Greece. Most models also agree on a substantial future expansion of suitable areas into northern and eastern Europe. About 83% of urban areas are expected to become suitable in the future, in contrast with ~ 49% nowadays. Our findings show that previous research is congruent in identifying wide suitable areas for Aedes albopictus across Europe and in the need to effectively account for climate change in managing and preventing its future spread.info:eu-repo/semantics/publishedVersio

    Urban population in Europe is increasingly exposed to vector-borne diseases transmitted by the Asian-Tiger mosquito

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    The Asian Tiger mosquito (Aedes albopictus) is already established in many countries of Europe and cities are particularly vulnerable to the spread of vector-borne diseases. We evaluated the suitability of 62 large urban areas in Europe to the establishment of this mosquito, based on the level of agreement between published predictions of its potential distribution. We classified levels of suitability and uncertainty according to the number of matching models at a 25 km cell size and retrieved the predominant class within the boundaries of each urban area. We analysed 7 independent predictions for current conditions and 5 for future conditions (2050-2080), as well as changes in classes between the two timeframes. Currently, 60% of the cities are suitable to the mosquito, 8% are unsuitable and 32% show high uncertainty. In the future, 87% will be suitable and none will be unsuitable, including cities in the British Isles and Scandinavia, which will have to adapt their public health policies.info:eu-repo/semantics/publishedVersio

    Data science strategies leading to the development of data scientists’ skills in organizations

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    The purpose of this paper is to compare the strategies of companies with data science practices and methodologies and the data specificities/variables that can influence the definition of a data science strategy in pharma companies. The current paper is an empirical study, and the research approach consists of verifying against a set of statistical tests the differences between companies with a data science strategy and companies without a data science strategy. We have designed a specific questionnaire and applied it to a sample of 280 pharma companies. The main findings are based on the analysis of these variables: overwhelming volume, managing unstructured data, data quality, availability of data, access rights to data, data ownership issues, cost of data, lack of pre-processing facilities, lack of technology, shortage of talent/skills, privacy concerns and regulatory risks, security, and difficulties of data portability regarding companies with a data science strategy and companies without a data science strategy. The paper offers an in-depth comparative analysis between companies with or without a data science strategy, and the key limitation is regarding the literature review as a consequence of the novelty of the theme; there is a lack of scientific studies regarding this specific aspect of data science. In terms of the practical business implications, an organization with a data science strategy will have better direction and management practices as the decision-making process is based on accurate and valuable data, but it needs data scientists skills to fulfil those goals.info:eu-repo/semantics/acceptedVersio

    A Critical Analysis of the Available In Vitro

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    Angiogenesis is a biological process with a central role in retinal diseases. The choice of the ideal method to study angiogenesis, particularly in the retina, remains a problem. Angiogenesis can be assessed through in vitro and in vivo studies. In spite of inherent limitations, in vitro studies are faster, easier to perform and quantify, and typically less expensive and allow the study of isolated angiogenesis steps. We performed a systematic review of PubMed searching for original articles that applied in vitro or ex vivo angiogenic retinal assays until May 2017, presenting the available assays and discussing their applicability, advantages, and disadvantages. Most of the studies evaluated migration, proliferation, and tube formation of endothelial cells in response to inhibitory or stimulatory compounds. Other aspects of angiogenesis were studied by assessing cell permeability, adhesion, or apoptosis, as well as by implementing organotypic models of the retina. Emphasis is placed on how the methods are applied and how they can contribute to retinal angiogenesis comprehension. We also discuss how to choose the best cell culture to implement these methods. When applied together, in vitro and ex vivo studies constitute a powerful tool to improve retinal angiogenesis knowledge. This review provides support for researchers to better select the most suitable protocols in this field

    αvβ3 and α5β1 integrin-specific ligands: From tumor angiogenesis inhibitors to vascularization promoters in regenerative medicine?

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    Integrins are cell adhesion receptors predominantly important during normal and tumor angiogenesis. A sequence present on several extracellular matrix proteins composed of Arg-Gly-Asp (RGD) has attracted attention due to its role in cell adhesion mediated by integrins. The development of ligands that can bind to integrins involved in tumor angiogenesis and brake disease progression has resulted in new investigational drug entities reaching the clinical trial phase in humans. The use of integrin-specific ligands can be useful for the vascularization of regenerative medicine constructs, which remains a major limitation for translation into clinical practice. In order to enhance vascularization, immobilization of integrin-specific RGD peptidomimetics within constructs is a recommended approach, due to their high specificity and selectivity towards certain desired integrins. This review endeavours to address the potential of peptidomimetic-coated biomaterials as vascular network promoters for regenerative medicine purposes. Clinical studies involving molecules tracking active integrins in cancer angiogenesis and reasons for their failure are also addressed.Prémios Santa Casa Neurociências - Prize Melo e Castro for Spinal Cord Injury Research; Portuguese Foundation for Science and Technology [Doctoral fellowship (PD/BDE/127835/2016) to L. A. Rocha; IF Development Grant to A. J. Salgado; national funds through grant TUBITAK/0007/2014]. This article has been developed under the scope of the projects NORTE-01-0145-FEDER-000013, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER); This work has been funded by FEDER funds, through the Competitiveness Factors Operational Programme (COMPETE), and by National funds, through the Foundation for Science and Technology (FCT), under the scope of the project POCI-01-0145-FEDER-007038info:eu-repo/semantics/publishedVersio
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