3,010 research outputs found
Footpaths design on renovation of city centres - a model of assessment
"First International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2019)"Nowadays, many cities are committed on improving the attractiveness of their historical centers through its renovation. When renovating city centres, one of the most important issues to take into account is the mobility in these central areas and the use of soft transport modes, so as to improve not only its attractiveness, but also its sustainability. In order to achieve this purpose, the walkability of the city centre should be promoted. The main purpose of this work is to present a set of indicators which can assess the footpaths design in the context of renovation of historical city centres, focusing on the walkability of these urban areas. The assessment of those issues allows the creation of different scenarios and reflects, as early as in the preliminary design phase, the overall quality of the proposed solution for the footpaths.(undefined
O ensino das ciências em escolas do 1ºCEB do concelho da Guarda
Neste trabalho pretende-se analisar as atitudes dos professores em relação aos princípios orientadores, objectivos gerais e específicos do programa do 1º Ciclo do Ensino Básico (1º CEB) referentes às atitudes científicas e ambientais a desenvolver. Discutem-se também os fundamentos pedagógicos do ensino das ciências que devem enformar a formação de professores do 1º CEB. Com este propósito fez-se um levantamento das práticas pedagógicas que enquadram a área do estudo do meio no 1º CEB e em particular aquelas que se centram na formação científica e na relação indivíduo-ambiente.
O nosso estudo exploratório centrou-se na percepção e atitudes dos professores do 1º CEB, tendo-se para o efeito considerado 8 escolas do Concelho da Guarda, onde decorrem os estágios pedagógicos, tendo sido distribuído um questionário sobre as práticas da educação científica e ambiental neste nível de ensino.
Os resultados referem-se a uma amostra de 29 sujeitos que manifestaram uma atitude positiva de reconhecimento dos objectivos de educação científica e ambiental constantes na área do estudo do meio. Confirmou-se que os nossos professores conhecem esses objectivos e valorizam a sua importância. Não encontrámos discriminação entre o tipo de actividades, “papel e lápis” vs experimentação ou entre o tipo de materiais comuns vs incomuns. A idade e tempo de serviço também não tem influência significativa nos resultados. Do ponto de vista atitudinal, os professores parecem preocupar-se com o ensino-aprendizagem destas temáticas, pelo que um estudo subsequente sobre as suas efectivas actividades no terreno parece impor-se, com vista a avaliar-se melhor as (eventuais) contradições entre a teoria e a prática dos professores deste nível de ensino.Fundação para a Ciência e a Tecnologia (FCT) - POCTI/CED/44187/2002.European Project FP6 Biohead-Citizen CIT2-CT-2004-506015
Contribution of an environmental monitoring system to evaluate the potential effect of urban air pollution
The growth of the world?s population has been followed by the increase of residents living in urban areas, which very often results in additional pressures concerning space, ecosystems, infrastructures, facilities and the way of life. The impact of pollutants, emitted into the atmosphere, on materials is enormous and could be irreversible. The effects of the air pollution in façades and on the structural systems lead to unexpected costs for the buildings maintenance and may be avoided if pollution monitoring systems exists.
This work presents a methodology to evaluate, on a regular basis, the potential impact of air pollution on historical buildings. It uses a monitoring system to collect samples of particulate matter (PM10 and PM2.5), particulate matter concentration levels and weather parameters. It is possible to act, in time, for the preservation and protection of this historical heritage by joining all of these data. This methodology could complement the studies of the environmental impact assessments on the historical buildings from the outdoor air pollution sources and contributes to the preservation and protection of the historical buildings. This work is being applied in the Portuguese midsized city of Vila Real, where the urban pollution assessment and their effects in urban historical buildings was considered the main goal.(undefined
Acacia saligna (Labill.) H. Wendl in the Sesimbra county: invaded habitats and potential distribution modeling
The aim of this study is to establish the spatial pattern of colonization and spread of Acacia saligna by predictive
modeling, susceptibility evaluation and to perform a cost-effective analysis in two sites of community
importance (Fernão Ferro/Lagoa de Albufeira and Arrábida/Espichel) in the Sesimbra County. The main goal is
to increase the knowledge on the invasive process and the potential distribution of the Acacia saligna in
Sesimbra County, namely in the Natura 2000 sites. The Artificial Neural Networks model was developed in
Open Modeller to predict the potential of occurrence of A. saligna, and is assumed to be conditioned by a set of
limiting factors that may be known or modeled. The base information includes a dependent variable (present
distribution of specie) and several variables considered as conditioning factors (topographic variables, land use,
soils characteristics, river and road distance), organized in a Geographical Information System (GIS) database.
This is used to perform spatial analysis, which is focused on the relationships between the presence or absence of
the specie and the values of the conditioning factors. The results show a high correspondence between higher
values of potential of occurrence and soils characteristics and distance to rivers; these factors seem to benefit the
specie’ invasion process. According to the conservation value of each cartographic unit, related to natural
habitats included in Habitats Directive (92/43/EEC), the coastal habitats (2130, 2250 and 2230) were the most
susceptible to invasion by A. saligna. The predicted A. saligna distribution allows for a more efficient
concentration and application of resources (human and financial) in the most susceptible areas to invasion, such
as the local and national Protected Areas and the Sites of Community Importance, and is useful to test
hypotheses about the specie range characteristics, habitats preferences and habitat partitioning
Is Metabolic syndrome truly a risk factor for male lower urinary tract symptoms or just an epiphenomenon?
To define whether the association of male lower urinary tract symptoms (LUTS) and metabolic syndrome (MS) is real or simply an epiphenomenon, 490 male adults (mean age 58 ± 9 years) underwent International Prostate Symptom Score (IPSS), physical and prostate digital examinations, blood analysis, and urinary tract transabdominal ultrasound with prostate volume measurement. Mild, moderate, and severe LUTS were found in 350 (71.4%), 116 (23.7%), and 24 (4.9%) patients, respectively. MS was present in 198 (40.4%) patients, representing 37.4% (131 of 350) of those with mild LUTS, 46.5% (54 of 116) of those with moderate, and 54.1% (13 of 24) of those with severe. The odds ratio of MS having moderate or severe LUTS was 2.1. MS was more common in older age, higher body mass index, and larger prostate size. Moderate and severe LUTS were more frequent in older age, lower levels of high density cholesterol, and higher blood pressure. Older age and body mass index had significant relative risk for lower urinary tract symptoms and only age remained independent factor for LUTS on multivariate analysis. Our results suggest that the association of male LUTS, prostate volume, and MS might be coincidental and related to older age2014sem informaçã
Functional nanostructured chitosan–siloxane hybrids
New organic–inorganic hybrids were prepared by a sol–gel method from the biopolymer chitosan and a silane coupling agent, 3-isocyanatopropyltriethoxysilane (ICPTES), in which covalent bridges, essentially composed of urea, bond the chitosan to the poly(siloxane) network. The structural characterization of the advanced chitosan–siloxane hybrids was performed by Fourier transform infrared spectroscopy, X-ray diffraction and 29Si and 13C nuclear magnetic resonance. The presence of siloxane nanodomains was detected by small angle X-ray diffraction. The chitosan–siloxane hybrids are bifunctional materials with interesting photoluminescent features and bioactive behaviour. The photoluminescence spectra display an additional high-energy band with longer lifetime, relatively to the characteristic emission of pure chitosan. This band is associated with electron–hole recombinations arising from silicon-related defects at the surface of the siliceous nanodomains. The bioactive behaviour of these materials was also evaluated; the apatite formation was shown to depend on the amount and arrangement of silanol groups
Simultaneous use of direct and reverse flotation in the production of iron ore concentrate plant.
The exploitation of low-grade iron ore deposits represents the current scenario for this business. Thus arise several types of research that aim at improvements and innovations as solutions to such situation. Therefore, herein, suggested is an alternative route for iron ore flotation that targets a higher mass recovery with concentrate within the market specification. First, the sample was deslimed at 38 ?m and with the underflow a cut was performed in the 74 ?m cyclone in order to separate the coarse particles from the fine. With the coarse particles, i.e. with the underflow, there a reverse flotation was carried on obtaining a concentrate with 67.7% of Fe and 0.9% of SiO2. In the fine particle overflow, direct flotation was done, generating a low-quality concentrate with 40.9% of Fe and 39.7% of SiO2. The mass recovery in direct flotation was 88% and in the reverse flotation was 61.1%. The concentrate generated from two flotations had a mass recovery of 67.4% with a content of Fe of 53.4% and 21.6% SiO2
Demographic expansion and contraction in a neotropical fish during the Late Pleistocene-Holocene
Demographic changes during the late Pleistocene-Holocene left signatures in the DNA of contemporary populations. These signatures reveal demographic phenomena like the increase or decrease in effective population size. In this paper we searched for signatures of demographic change in the DNA of the Neotropical freshwater fish Poecilia vivipara . Also, we investigated whether demographic changes are correlated with palaeoclimatic events of the late Pleistocene-Holocene, in particular, if changes in effective population size are correlated with expansion and contraction of available habitats, induced by global ice-volume changes and sea-level fluctuations. We used Bayesian Skyline Plot (BSP) analysis with sequences from the mitochondrial gene cytochrome b to estimate the ancestral demography of the Neotropical freshwater fish P. vivipara . To test the assumptions of neutrality and absence of population structure we used Tajima?s D and Spatial Analysis of Molecular Variance (SAMOVA), respectively. Effective population size of P. vivipara remained stable until 75,000 years ago, increased by 10-fold reaching a maximum at approximately 25,000 years ago, then suddenly declined at the Pleistocene-Holocene boundary. Variation in effective population size in P. vivipara correlates with expansion and contraction of habitats induced by sea-level fluctuations, caused by the advance and retreat of ice sheets during the Last Glacial Maximum (LGM).Fil: Costa, Carolina L. N.. Universidade Estadual de Campinas; BrasilFil: Perez, Sergio Ivan. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Antropología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Louvise, José. Faculdade Do Vale Do Jaguaribe; BrasilFil: Tonhatti, Carlos H.. Universidade Estadual de Campinas; BrasilFil: Clemente Carvalho, Rute B. G.. Queens University. Department Of Biology; CanadáFil: Petryna, Ana Mabel. Universidade Federal do Rio de Janeiro; BrasilFil: dos Reis, S. F.. Universidade Estadual de Campinas; Brasi
Glyphosate-Based Herbicide Toxicophenomics in Marine Diatoms: Impacts on Primary Production and Physiological Fitness
Glyphosate is the main active component of the commercial formulation Roundup®, the most widely used chemical herbicide worldwide. However, its potential high toxicity to the environment and throughout trophic webs has come under increasing scrutiny. The present study aims to investigate the application of bio-optical techniques and their correlation to physiological and biochemical processes, including primary productivity, oxidative stress, energy balance, and alterations in pigment and lipid composition in Phaeodactylum tricornutum, a representative species of marine diatoms, using the case study of its response to the herbicide glyphosate-based Roundup® formulation, at environmentally relevant concentrations. Cultures were exposed to the herbicide formulation representing effective glyphosate concentrations of 0, 10, 50, 100, 250, and 500 μg L−1. Results showed that high concentrations decreased cell density; furthermore, the inhibition of photosynthetic activity was not only caused by the impairment of electron transport in the thylakoids, but also by a decrease of antioxidant capacity and increased lipid peroxidation. Nevertheless, concentrations of one of the plastidial marker fatty acids had a positive correlation with the highest concentration as well as an increase in total protein. Cell energy allocation also increased with concentration, relative to control and the lowest concentration, although culture growth was inhibited. Pigment composition and fatty acid profiles proved to be efficient biomarkers for the highest glyphosate-based herbicide concentrations, while bio-optical data separated controls from intermediate concentrations and high concentrations.info:eu-repo/semantics/publishedVersio
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