Abstract. On the night of 4 March 2001, at Entre-os-Rios (Northern Portugal), the Hintze Ribeiro centennial bridge collapsed killing 59 people traveling in a bus and three cars that were crossing the Douro River. According to the national authorities, the collapse was due to two decades of uncontrolled sand extraction which compromised the stability of the bridge's pillars, together with underestimating the warnings from divers and technicians. In this work we do not intend to corroborate or contradict the official version of the accident's causes, but only demonstrate the potential of Multi-Temporal Interferometric techniques for detection and monitoring of deformations in structures such as bridges, and consequently the usefulness of the derived information in some type of early warning system to help prevent new catastrophic events. Based on the analysis of 52 ERS-1/2 covering the period from May 1995 to the fatal occurrence, we were able to detect significant movements, reaching rates of 20 mm yr−1, in the section of the bridge that fell into the Douro River, which are obvious signs of the bridge's instability. These promising results demonstrate that with the new high-resolution synthetic aperture radar satellite scenes it is possible to develop interferometric based methodologies for structural health monitoring.
One of the main obstacles to the implementation of Conservation Agriculture (CA) in subSaharan Africa is the priority given to using crop residues as cattle feed rather than mulching material. As documented in past projects (e.g. CA-SARD, CA2Africa, ABACO), in this way the CA approach will not reach its full potential - particularly in countries with a limited biomass production due to climatic conditions. To identify pathways for enabling an implementation of CA that is not in conflict with other goals of farmers' livelihoods (e.g. livestock farming), we used a transformative learning approach with farmers and other stakeholders in Laikipia County (Kenya). The learning elements comprised: a timeline that encompasses the past promotion activities; stakeholder mapping which highlights the various stakeholders involved and their influence; non-scripted participatory videos filmed by the stakeholders themselves that show the farming system from different perspectives; focus group discussions structured by the Qualitative expert Assessment Tool for CA adoption in Africa (QAToCA). Challenges to CA adoption that were jointly identified include the competition for fodder, a lack of financial resources to get started with CA. There are knowledge gaps on proper application of CA equipment, on the fodder production and conservation options and, lastly, on sustainable crop-livestock production systems. Furthermore, farmers feel disconnected from existing governmental support. However, our findings highlight solutions which enable feeding the soil "and" feeding the cow. Some farmers already have started to grow forages on their farms in order to reduce dependence on crop residues as a feeding source – an approach which had not been promoted during past projects. This shows the importance of an enabling environment provided by government programs which supports long-term extension efforts combined with farmers' willingness to jointly learn towards a more sustainable agriculture. On farms where both systems (CA and conventional) are practised, women play an important role by experimenting with CA practices, thereby realising promising results in terms of yield and drought resilience. Furthermore, our findings underline the need for a long-term monitoring of innovation processes which is often not possible within short-term term research projects and promotion programs.
Abstract. In the morning of the 20 February of 2010 an extreme precipitation event occurred over Madeira Island. This event triggered several flash floods and mudslides in the southern parts of the island, resulting in 42 confirmed deaths, 100 injured, and at least 8 people still missing. These extreme weather conditions were associated to a weather frontal system moving northeastwards embedded in a low pressure area centered in the Azores archipelago. This storm was one in a series of such storms that affected Portugal, Spain, Morocco and the Canary islands causing flooding and strong winds. These storms were bolstered by an unusually strong sea surface temperature gradient across the Atlantic Ocean. In this study, the WRF model is used to evaluate the intensity and predictability of this precipitation extreme event over the island. The synoptic/orographic nature of the precipitation is also evaluated, as well as the sensitivity of the model to horizontal resolution and cumulus parameterization. Orography was found to be the main factor explaining the occurrence, amplitude and phase of precipitation over the Island.
A Duarte-de-Araújo,1–3 P Teixeira,1,2 V Hespanhol,4,5 J Correia-de-Sousa1,2,61Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; 2ICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães, Portugal; 3Respiratory Department, H. Sª Oliveira, Guimarães, Portugal; 4Department of Pneumology, Centro Hospitalar de S. João, Porto, Portugal; 5Faculty of Medicine (FMUP), University of Porto, Porto, Portugal; 6Horizonte Family Health Unit, Matosinhos, PortugalBackground and objectives: Inhalers mishandling remain an important clinical issue worldwide. The aim of this study was to evaluate inhalation technique in stable COPD out-patients. The variables under study were type of inhaler device (ID), patients' preference for an inhaler, number of IDs used by each patient, beliefs about inhaler medication and some demographic, clinical and functional patients' characteristics. We aim to assess how they are related to inhalation technique.Methods: A cross-sectional study was conducted in a hospital outpatient respiratory care. COPD patients over 40 years old, diagnosed according to GOLD criteria, and using IDs were included consecutively. The Beliefs about Medicines Questionnaire (BMQ), a demographic and a clinical survey were applied. The number of IDs used by each patient and the patients' preference for some IDs were recorded. Patients were asked to demonstrate the use of their prescribed inhalation devices, and inhaler technique was assessed by using previously defined checklists, including essential steps and critical errors. A statistics analysis was then performed.Results: We studied 300 subjects performing a total of 521 inhalation manoeuvers with 10 different IDs. At least one step incorrectly performed was found in 48.2% of demonstrations and in 29.9% critical errors were observed. Misuse was related to priming/loading in 6.9%, to inhalation manoeuver in 13.1% and to both in 10%. There was a statistically significant association between critical errors and type of ID (P<0.001). No significant relationship was found between correct performance of key manoeuvers and patients' preference or number of inhalers used per patient. Misuse due to critical errors was observed in 39.3% of patients and was positively related to female gender, age ≥65, lower education level and lower socioeconomic status (higher Graffar classification score), but not to patients' clinical or functional characteristics. In the sub-group of patients presenting critical errors when using IDs, there was a statistically significant inverse association between BMQ Necessity score and number of critical errors.Conclusions: Inhalers mishandling remains disappointingly common. A good inhalation technique depends on the type of ID, and failure of inhalation manoeuver was the main cause of ID misuse. It was not associated to multiple inhalers' use nor to patient's preference, but to the patient's beliefs about the necessity to use them. Elderly patients, women and those with lower education level or lower socioeconomic status demonstrate a worse inhalation technique.Keywords: COPD; Inhalation technique; Inhaler devices
A new approach to assess environmental integrity based on PRC analysis was proposed, tested, validated and developed. Environmental health assessment and community studies usually result in complex biological data sets. In order to find ecologically relevant patterns and tendencies from such sets of data it is necessary to reduce all the information to a summarised and simplified form, which might be more easily interpreted by ecologists, politicians, end-users and the population in general. However, several multivariate ordination methods currently used (e.g. redundancy analysis, principal component analysis, or multi-dimensional scaling) produce complex diagrams for the non-ecologist, which do not allow changes in biological communities over time to be easily understood. Here, we propose a recently developed method, principal response curves (PRC) analysis, to overcome these issues. This method has advantages over traditional ordination techniques, or any biotic index, in that it provides a powerful statistical analysis of temporal data series along spatial gradients. The PRC technique can make use of non-disturbed or unpolluted areas as reference sites with which other areas are compared, making it possible to assess changes in species composition between different areas over time. Moreover, individual species responses to stress agents can be inferred from the PRC curves. As well as providing insights into the behaviour of natural ecosystems‹in particular, how ecosystem integrity changes over time‹this new approach can potentially provide a practical tool for monitoring and implementing environmental policy instruments
The article aims to evaluate the Portuguese building stock energy policies and strategy for energy saving in buildings among the EU members. It was found out the average heat transfer coefficients of the main structural elements of Portuguese Buildings and analyzed the U-values of this elements considering different time periods. The fundamentals of this study were funded by the Agency for Development and Innovation (ADI) and co-financed by the European Regional Development Fund (FEDER) through the Operational Program for Competitiveness Factors (POFC) assigned to the Building Physics and Construction Technology Laboratory with the reference SB Tool ...
Abstract. An analysis of the cloud-to-ground discharges (CGD) over Portugal is carried out using data collected by a network of sensors maintained by the Portuguese Meteorological Institute for 2003–2009 (7 yr). Only cloud-to-ground flashes are considered and negative polarity CGD are largely dominant. The total number of discharges reveals a considerable interannual variability and a large irregularity in their distribution throughout the year. However, it is shown that a large number of discharges occur in the May–September period (71%), with a bimodal distribution that peaks in May and September, with most of the lightning activity recorded in the afternoon (from 16:00 to 18:00 UTC). In spring and autumn the lightning activity tends to be scattered throughout the country, whereas in summer it tends to be more concentrated over northeastern Portugal. Winter generally presents low lightning activity. Furthermore, two significant couplings between the monthly number of days with discharges and the large-scale atmospheric circulation are isolated: a regional forcing, predominantly in summer, and a remote forcing. In fact, the identification of daily lightning regimes revealed three important atmospheric conditions for triggering lightning activity: regional cut-off lows, cold troughs induced by remote low pressure systems and summertime regional low pressures at low-tropospheric levels combined with a mid-tropospheric cold trough.
[EN]The adsorption isotherms of nitrogen at 77 K have been determined on two series of activated carbons and two samples of activated carbon fibres. The carbons were highly microporous and contained varying amounts of different forms of microporosity. Characterization of the carbons was undertaken using an alternative linear form of the BET equation and the results of the BET parameters obtained have been compared with those obtained from the usual classical linear form of the equation. The surface areas calculated from the two linear forms were similar while the C values were quite different. The C values obtained from the alternative linear form appeared to be more reasonable, being consistent with and related to the microporous character of these carbons. The alternative linear form gave BET plots which were more sensitive to deviations from linearity allowing the relative pressure range for the application of the BET equation to be determined without any ambiguity and more precisely. ; The authors thank DGICYT (Project PB90-0067) and FICYT for financial support. R. C. Bansal is grateful to the Ministerio de Educación y Ciencia, Government of Spain for a financial grant for his stay at the Instituto Nacional del Carb6n in Oviedo, Spain. J.C. de Sousa also thanks the Univ. Est. de Maringa and CNPq (Brazil) for a grant. ; Peer reviewed
Wireless radio links deployed over aquatic areas (e.g., sea, estuaries or harbors) are affected by the conductive properties of the water surface, strengthening signal reflections and increasing interference effects. Recurrent natural phenomena such as tides or waves cause shifts in the water level that, in turn, change the interference patterns and cause varying impairments to propagation over water surfaces. In this work, we aim at mitigating the detrimental impact of tides on the quality of a line-of-sight over-water link between an onshore station and a surface node, targeting mission data transfer scenarios. We consider different types of surface nodes, namely, autonomous underwater vehicles, unmanned surface vehicles and buoys, and we use WiFi technology in both 2.4 GHz and 5 GHz frequency bands. We propose two methods for link distance/height design: (i) identifying a proper Tx-Rx distance for improved link quality at each point of the tidal cycle; (ii) defining the height/distance that minimizes the path loss averaged during the whole tidal cycle.Experimental results clearly show the validity of our link quality model and the interest of method (i). Analytical results confirm method (ii) and show that it outperforms, in both frequency bands, the common practice of placing onshore antennas at the largest possible height and/or surface nodes at a short but arbitrary distance. ; This work was partially supported by National Funds through FCT/MCTES (Portuguese Foundation for Science and Technology), within the CISTER Research Unit (UIDP/UIDB/04234/2020) and by FCT through the European Social Fund (ESF) and the Regional Operational Programme (ROP) Norte 2020, under grant 2020.06685.BD, as well as by the European Union's Horizon 2020 Marine robotics research infrastructure network project under grant agreement No 731103. This support is gratefully acknowledged. ; info:eu-repo/semantics/publishedVersion
Evolutionary analyses have revealed an origin of pandemic HIV-1 group M in the Congo River basin in the first part of the XXth century, but the patterns of historical viral spread in or around its epicentre remain largely unexplored. Here, we combine epidemiologic and molecular sequence data to investigate the spatiotemporal patterns of the CRF02_AG clade. By explicitly integrating prevalence counts and genetic population size estimates we date the epidemic emergence of CRF02_AG at 1973.1 (1972.1, 1975.3 95% CI). To infer their phylogeographic signature at a regional scale, we analyze pol and env time-stamped sequence data from 8 countries using a Bayesian phylogeographic approach based on a discrete asymmetric model. Our data confirms a spatial origin of this clade in the Democratic Republic of Congo (DRC) and suggests that viral dissemination to Cameroon occurred at an early stage of the evolutionary history of CRF02_AG. We find considerable support for epidemiological linkage between neighbour countries. Compilation of ethnographic data suggests that well-supported viral migration was related with chance exportation events rather than by sustained human migratory flows. Finally, using sequence data from 15 locations in Cameroon, we use relaxed random walk models to explore the spatiotemporal dynamics of CRF02_AG at a finer geographical detail. Phylogeographic dispersal in continuous space reveals that at least two distinct CRF02_AG lineages are circulating in overlapping regions that are evolving at different evolutionary and diffusion rates. Altogether, by combining molecular and epidemiological data, our results provide a time scale for CRF02_AG, place its spatial root within the putative root of group-M diversity and propose a scenario for the spatiotemporal patterns of a successful HIV-1 lineage both at a regional and country-scale.
The functionalization of single-walled carbon nanotubes (SWCNTs) with luminescent sp3 defects has greatly improved their performance in applications such as quantum light sources and bioimaging. Here, we report the covalent functionalization of purified semiconducting SWCNTs with stable organic radicals (perchlorotriphenylmethyl, PTM) carrying a net spin. This model system allows us to use the near-infrared photoluminescence arising from the defect-localized exciton as a highly sensitive probe for the short-range interaction between the PTM radical and the SWCNT. Our results point toward an increased triplet exciton population due to radical-enhanced intersystem crossing, which could provide access to the elusive triplet manifold in SWCNTs. Furthermore, this simple synthetic route to spin-labeled defects could enable magnetic resonance studies complementary to in vivo fluorescence imaging with functionalized SWCNTs and facilitate the scalable fabrication of spintronic devices with magnetically switchable charge transport. ; The authors thank Dr. Vega Lloveras for performing electron paramagnetic resonance measurements. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 817494 "TRIFECTs"). S.Z. acknowledges funding from the Alexander von Humboldt Foundation, and A.H. from the European Research Council (ERC) under the grant agreement no. 772195 and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy EXC-2111-390814868. This work was also supported by the MICIU of Spain (PID2019-111682RB-I00), the Generalitat de Catalunya (2017-SGR-918), and the Severo Ochoa FUNFUTURE (CEX2019-000917-S). J.A.d.S. is enrolled in the Materials Science Ph.D. program of UAB. J.A.d.S. thanks the FPI fellowship. ; Peer reviewed
This work received financial support from REQUIMTE/LAQV, National Funds (FCT, Fundação para a Ciência e Tecnologia) through projects UID/QUI/50006/2019 and Norte-01-0145-FEDER-000011-RL1–QUALIFOOD and European Union through Marie Curie Actions FP7-PEOPLE-2013-IRSES (project no. 612545 entitled "GMOsensor–Monitoring Genetically Modified Organisms in Food and Feed by Innovative Biosensor Approaches"). C. Pereira and M. F. Barroso are grateful to FCT for FCT Investigator contract (IF/01080/ 2015) and post-doctoral grant (SFRH/BPD/78845/2011), respectively, financed by POPH-QREN (subsidized by FSE and MCTES): Tipologia 4.1 – Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência, Tecnologia e Ensino Superior and to REQUIMTE/ LAQV.
