1,463 research outputs found

    Caracterização da rigidez de misturas betuminosas em ensaios de tracção indirecta por compressão diametral de provetes cilíndricos

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    As misturas betuminosas utilizadas nas camadas dos pavimentos rodoviários têm comportamento mecânico do tipo visco-elástico. Na prática do dimensionamento, este comportamento é definido pelo módulo de rigidez e pelo coeficiente de Poisson que caracterizam o comportamento elástico linear, mas admitindo que estes parâmetros são dependentes da temperatura e da frequência de aplicação das cargas. A norma europeia EN 12697-26 diz respeito à caracterização da rigidez de misturas betuminosas fabricadas a quente em ensaios com carregamentos repetidos à flexão, tracção indirecta ou tracção directa uniaxial. Esta norma contempla o ensaio de tracção indirecta por compressão diametral de provetes cilíndricos. O Instituto Superior Técnico possui o equipamento NAT que tem permitido o desenvolvimento de estudos baseados nesta técnica de ensaio. O artigo apresenta as principais conclusões de alguns desses estudos relacionadas, essencialmente, com a exactidão do método de ensaio e a sua adequação para caracterizar misturas betuminosas de aplicação corrente na construção e reabilitação das estradas da rede rodoviária nacional. É descrito ainda um modelo de previsão do módulo de rigidez, validado e calibrado para os resultados experimentais obtidos

    Consideration of non-linearity of soils behaviour in the numerical modelling of road pavements

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    O objectivo principal desta comunicação é evidenciar a importância de considerar a nãolinearidade do comportamento dos solos de fundação na modelação numérica dos pavimentos rodoviários, para fins de dimensionamento estrutural. A instrumentação e observação de dois trechos experimentais numa estrada em Lisboa permitiram analisar o comportamento dos solos com esta finalidade. Durante a construção dos aterros foram realizados ensaios de carga com placa e ensaios de carga com pneu. A análise estrutural dos solos da fundação dos pavimentos, pelo método dos elementos finitos, permitiu concluir que a utilização do modelo elástico nãolinear foi a metodologia mais adequada à modelação do comportamento observado durante os ensaios. A consideração de comportamento elástico linear, tão corrente no dimensionamento dos pavimentos, mostrou-se inadequada e com tendência para subestimar a rigidez da fundação.The main objective of this paper is to point out the importance of non linearity of soils foundation behaviour in the road pavement modelling, for structural design purposes. The monitoring of two full-scale instrumented pavements in a road in Lisbon had allowed to this objective. During the test sections constructions, plate load tests and wheel load tests were carried out. The structural analysis of soils behaviour, by the finite elements method, allowed to conclude that the best adjustment to the experimental results was performed with the non-linear elastic model. The elastic linear behaviour, so worldwide used in pavements design, has shown inadequate and with trend to under predict foundation stiffness

    IL-10 underlies distinct susceptibility of BALB/c and C57BL/6 mice to Mycobacterium avium infection and influences efficacy of antibiotic therapy

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    Increased production of IL-10 has been frequently associated with augmented susceptibility to infection. However, the correlation between IL-10 activity and susceptibility to mycobacterial infection is still uncertain. Although studies using transgenic mice overexpressing IL-10 consistently showed an increased susceptibility to mycobacterial infection, experimental approaches in which IL-10 activity was reduced or abrogated originated inconclusive data. We show here that this controversy might be due to the mouse strains used in the various experimental procedures. Our results show that BALB/c mice are more susceptible than C57BL/6 to Mycobacterium avium infection. This increased susceptibility of BALB/c mice is, to a great extent, due to distinct activity of IL-10 between the two mouse strains. In accordance, reduction of IL-10 activity through the administration of anti-IL-10R mAb, or the absence of IL-10 as studied in IL-10 knockout mice, clearly decreased the susceptibility of BALB/c mice to M. avium but had a less obvious effect in C57BL/6 mice. Moreover, abrogation of IL-10 activity in infected BALB/c mice increased the efficacy of antimycobacterial therapy, whereas for the C57BL/6 mice it produced no effect. These observations show that the activity of IL-10 in response to the same mycobacterial stimulus influences not only the susceptibility to infection but also the efficacy of antimycobacterial therapy. This should now be considered in the context of human response to mycobacterial infection, particularly as a possible strategy to improve treatment against infections by mycobacteria

    Landscape Ecology dialogue: facing societal and environmental challenges in Southern Europe

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    A Universidade de Évora aprovou, em 2013, o Mestrado em Ecologia da Paisagem, o 1º em Portugal, cuja 1ª edição vai ter lugar no próximo ao letivo. A presente conferência tem como objetivo dar a conhecer e divulgar o referido mestrado aos potenciais interessados, trazendo para o diálogo os desafios que atualmente se colocam em Ecologia da Paisagem, nomeadamente os sociais e ambientais, num contexto transdisciplinar que lhe é inerente. Serão abordados temas dentro de um vasto leque de realidades, questões e escalas de análise, desde o ensino à investigação e à sua aplicação prática, para o que se convidaram especialistas e investigadores de diferentes países, com diferentes competências e formações. Pretende-se identificar as questões mais atuais e os desafios a considerar no futuro, articulando ensino e investigação e equacionado de que forma a Ecologia da Paisagem contribui para dar resposta às rápidas transformações e dinâmicas territoriais e ambientais. As apresentações da conferência podem ser solicitadas à organização por correio electrónico

    Patterns of Mycobacterium tuberculosis-complex excretion and characterization of super-shedders in naturally-infected wild boar and red deer

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    Wild boar (Sus scrofa) and red deer (Cervus elaphus) are the main maintenance hosts for bovine tuberculosis (bTB) in continental Europe. Understanding Mycobacterium tuberculosis complex (MTC) excretion routes is crucial to define strategies to control bTB in free-ranging populations, nevertheless available information is scarce. Aiming at filling this gap, four different MTC excretion routes (oronasal, bronchial-alveolar, fecal and urinary) were investigated by molecular methods in naturally infected hunter-harvested wild boar and red deer. In addition MTC concentrations were estimated by the Most Probable Number method. MTC DNA was amplified in all types of excretion routes. MTC DNA was amplified in at least one excretion route from 83.0% (CI95 70.8-90.8) of wild ungulates with bTB-like lesions. Oronasal or bronchial-alveolar shedding were detected with higher frequency than fecal shedding (p 10(3) CFU/g or mL (referred here as super-shedders). Red deer have a significantly higher risk of being super-shedders compared to wild boar (OR = 11.8, CI95 2.3-60.2). The existence of super-shedders among the naturally infected population of wild boar and red deer is thus reported here for the first time and MTC DNA concentrations greater than the minimum infective doses were estimated in excretion samples from both species.We are grateful to all owners, hunters and hunting organizations that helped us to collect samples. Thanks are also due to Monica Cunha (INIAV, Portugal) for her advice during the setup of the laboratorial diagnosis techniques. Nuno Santos was supported by the Fundacao para a Ciencia e a Tecnologia (Ph.D. Grant SFRH/BD/69390/2010). This is also a contribution to MINECO Plan Nacional grant AGL2014-56305 and FEDER, and to the EU FP7 grant ANTIGONE # 278976

    Intra-urban variation in tuberculosis and community socioeconomic deprivation in Lisbon metropolitan area: a Bayesian approach

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    Background: Multidrug resistant tuberculosis (MDR-TB) is a recognized threat to global efforts to TB control and remains a priority of the National Tuberculosis Programs. Additionally, social determinants and socioeconomic deprivation have since long been associated with worse health and perceived as important risk factors for TB. This study aimed to analyze the spatial distribution of non-MDR-TB and MDR-TB across parishes of the Lisbon metropolitan area of Portugal and to estimate the association between non-MDR-TB and MDR-TB and socioeconomic deprivation. Methods: In this study, we used hierarchical Bayesian spatial models to analyze the spatial distribution of notification of non-MDR-TB and MDR-TB cases for the period from 2000 to 2016 across 127 parishes of the seven municipalities of the Lisbon metropolitan area (Almada, Amadora, Lisboa, Loures, Odivelas, Oeiras, Sintra), using the Portuguese TB Surveillance System (SVIG-TB). In order to characterise the populations, we used the European Deprivation Index for Portugal (EDI-PT) as an indicator of poverty and estimated the association between non-MDR-TB and MDR-TB and socioeconomic deprivation. Results: The notification rates per 10,000 population of non-MDR TB ranged from 18.95 to 217.49 notifications and that of MDR TB ranged from 0.83 to 3.70. We identified 54 high-risk areas for non-MDR-TB and 13 high-risk areas for MDR-TB. Parishes in the third [relative risk (RR) = 1.281, 95% credible interval (CrI): 1.021–1.606], fourth (RR = 1.786, 95% CrI: 1.420–2.241) and fifth (RR = 1.935, 95% CrI: 1.536–2.438) quintile of socioeconomic deprivation presented higher non-MDR-TB notifications rates. Parishes in the fourth (RR = 2.246, 95% CrI: 1.374–3.684) and fifth (RR = 1.828, 95% CrI: 1.049–3.155) quintile of socioeconomic deprivation also presented higher MDR-TB notifications rates. Conclusions: We demonstrated significant heterogeneity in the spatial distribution of both non-MDR-TB and MDR-TB at the parish level and we found that socioeconomically disadvantaged parishes are disproportionally affected by both non-MDR-TB and MDR-TB. Our findings suggest that the emergence of MDR-TB and transmission are specific from each location and often different from the non-MDR-TB settings. We identified priority areas for intervention for a more efficient plan of control and prevention of non-MDR-TB and MDR-TB. Graphical Abstract: [Figure not available: see fulltext.] © 2022, The Author(s).This work has been funded by National funds, through the Foundation for Science and Technology (FCT)—project UIDB/50026/2020, UIDP/50026/2020 and PTDC/SAU-PUB/29521/2017. This study was also supported by FEDER through the Operational Programme Competitiveness and Internationalization and national funding through the Foundation for Science and Technology—FCT (Portuguese Ministry of Science, Technology and Higher Education) under the Unidade de Investigação em Epidemiologia—Instituto de Saúde Pública da Universidade do Porto (EPIUnit) (UIDB/04750/2020). Ana Isabel Ribeiro was supported by National Funds through FCT, under the programme of ‘Stimulus of Scientific Employment—Individual Support’ within the contract CEECIND/02386/2018

    Evaluation of drug-resistant tuberculosis treatment outcome in Portugal, 2000-2016

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    Treatment of drug-resistant tuberculosis (TB), which is usually less successful than that of drug-susceptible TB, represents a challenge for TB control and elimination. We aimed to evaluate treatment outcomes and to identify the factors associated with death among patients with MDR and XDR-TB in Portugal. We assessed MDR-TB cases reported for the period 2000-2016, using the national TB Surveillance System. Treatment outcomes were defined according to WHO recommendations. We identified the factors associated with death using logistic regression. We evaluated treatment outcomes of 294 MDR- and 142 XDR-TB patients. The treatment success rate was 73.8% among MDR- and 62.7% among XDR-TB patients (p = 0.023). The case-fatality rate was 18.4% among MDR- and 23.9% among XDR-TB patients. HIV infection (OR 4.55; 95% CI 2.31-8.99; p < 0.001) and resistance to one or more second-line injectable drugs (OR 2.73; 95% CI 1.26-5.92; p = 0.011) were independently associated with death among MDR-TB patients. HIV infection, injectable drug use, past imprisonment, comorbidities, and alcohol abuse are conditions that were associated with death early on and during treatment. Early diagnosis of MDR-TB and further monitoring of these patients are necessary to improve treatment outcome.This work was developed under the scope of the project NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-000023, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) and projects PTDC/SAU-PUB/29521/2017. This work was partially supported by “Contratos-Programa” UIDB/50026/2020 and UIDB/04050/2020 funded by national funds through the FCT - Foundation for Science and Technology, I.P. OO is supported by the project NORTE-08-5369-FSE-000041, financed by the Operational Program NORTE 2020 and co-financed by the European Social Fund through a doctoral grant (UMINHO/BD/47/2016). This work was also supported by national funds through the FCT, I.P., under the project UIDB / 04750/2020

    Phylogeography of 27,000 SARS-CoV-2 genomes: Europe as the major source of the COVID-19 pandemic

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    Supplementary Material available at: https://www.mdpi.com/2076-2607/8/11/1678/s1The novel coronavirus SARS-CoV-2 emerged from a zoonotic transmission in China towards the end of 2019, rapidly leading to a global pandemic on a scale not seen for a century. In order to cast fresh light on the spread of the virus and on the effectiveness of the containment measures adopted globally, we used 26,869 SARS-CoV-2 genomes to build a phylogeny with 20,247 mutation events and adopted a phylogeographic approach. We confirmed that the phylogeny pinpoints China as the origin of the pandemic with major founders worldwide, mainly during January 2020. However, a single specific East Asian founder underwent massive radiation in Europe and became the main actor of the subsequent spread worldwide during March 2020. This lineage accounts for the great majority of cases detected globally and even spread back to the source in East Asia. Despite an East Asian source, therefore, the global pandemic was mainly fueled by its expansion across and out of Europe. It seems likely that travel bans established throughout the world in the second half of March helped to decrease the number of intercontinental exchanges, particularly from mainland China, but were less effective between Europe and North America where exchanges in both directions are visible up to April, long after bans were imposed.This work was supported by strategic project ICVS/3B’s (UID/Multi/50025), financed by Fundação para a Ciência e Tecnologia/MCTES through national funds (PIDDAC) to Teresa Rito. Martin B. Richards and Maria Pala received support from a Leverhulme Doctoral Scholarship program. This work was partially supported by project NORTE-01-0145-FEDER000009) by Norte Portugal Regional Operational Program (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) and by “Contrato-Programa” UIDB/04050/2020 funded by Portuguese national funds through the Fundação para a Ciência e Tecnologia to Pedro A. Soares

    First description of food-borne Salmonella enterica resistance regions R1 and R3 associated with IS26 elements

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    In this study, we assessed the presence of IS26 in food-borne ASSuT-type Salmonella enterica isolates. A new genetic region (R3) wasdescribed, that included a C14 caspase gene between IS26 elements. R3 was present in two Salmonella Rissen isolates from a swine carcass anda meat handler, collected at the same abattoir. Furthermore, a new rearrangement of resistance region R1, harboring the blaTEM-1 gene flanked byIS26 elements, was identified in Salmonella Typhimurium and Salmonella 4,[5],12:i:-, from different samples. This study highlights the zoonoticpotential of Salmonella spp. isolates and the possible role of IS26 in the mobilization of resistance genes.In this study, we assessed the presence of IS26 in food-borne ASSuT-type Salmonella enterica isolates. A new genetic region (R3) wasdescribed, that included a C14 caspase gene between IS26 elements. R3 was present in two Salmonella Rissen isolates from a swine carcass anda meat handler, collected at the same abattoir. Furthermore, a new rearrangement of resistance region R1, harboring the blaTEM-1 gene flanked byIS26 elements, was identified in Salmonella Typhimurium and Salmonella 4,[5],12:i:-, from different samples. This study highlights the zoonoticpotential of Salmonella spp. isolates and the possible role of IS26 in the mobilization of resistance genes

    Brain interference: Revisiting the role of IFNγ in the central nervous system

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    Interferon gamma (IFN-gamma) is a pro-inflammatory cytokine, first described as a secreted molecule capable of interfering with viral replication. Since then, numerous other important actions in the context of the immune response to invading pathogens (including those invading the brain) have been ascribed to this pleiotropic cytokine. Nevertheless, the precise role of IFN gamma in neuropsychiatric and neurodegenerative disorders, and its possible contribution to the regulation of normal brain function, remains enigmatic. This review integrates and considers current knowledge about IFN gamma actions with accumulating evidence of its importance on neurocytogenesis, synaptic plasticity and neurodegeneration within the framework of brain health and disease.Portuguese Science Foundation (FCT) for providing fellowships to S. Monteiro (SFRH/BD/69311/2010) and S. Roque (SFRH/BPD/72710/2011). Work by the authors was co-funded by Programa Operacional Regional do Norte (ON.2 – O Novo Norte), Quadro de Referência Estratégico Nacional (QREN), through the Fundo Europeu de Desenvolvimento Regional (FEDER), the “Programa Operacional Regional do Norte (ON.2 SR&TD Integrated Program – NORTE-07-0124-FEDER-000021), Quadro de Referência Estratégico Nacional (QREN), através do Fundo Europeu de Desenvolvimento Regional (FEDER)”, and by national funds from the FCT (PEst-C/SAU/LA0026/2013), and “Fundo Europeu de Desenvolvimento Regional (FEDER), através do COMPETE (FCOMP-01-0124-FEDER-037298)”info:eu-repo/semantics/publishedVersio
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