Instituto Politécnico de Lisboa
Recent publications
This paper is focused on the electrical and mechanical performance of aluminum-copper hybrid busbars subjected to corrosion over time. Two different types of hybrid busbars with joints produced by conventional fastening with M8 hexagonal socket head bolt-nut pairs made from medium carbon steel and by a new injection lap riveting process with semi-tubular rivets made from the material of the softer conductor are used and subjected to salt spray and electrochemical tests. Electrical resistance measurements performed on hybrid busbars taken from the corrosion testing cabinet at the end of each exposure period allow concluding that the new injection lap riveted hybrid busbars have a better electrical performance over time due to the elimination of fasteners with a higher electrical resistivity than aluminum and copper and to the elimination of the aluminum-steel and copper-steel galvanic pairs. The capability of the injection lap riveted hybrid busbars to withstand shear forces after corrosion testing also revealed to be adequate and like those of the original (uncorroded) hybrid busbars.
En un momento histórico en el que el futuro se concibe como una amenaza, parece altamente relevante educar en la capacidad de imaginar futuros deseables. En esta línea, la Educación para el Futuro (EpF), de tradición anglosajona, representa una referencia de trabajo para responder a las imágenes negativas sobre la idea del provenir. Por otro lado, las competencias de cultura democrática definidas por el Consejo de Europa dan pie a la elaboración de un marco teórico que incluye la imaginación de futuros democráticos y sostenibles como uno de sus principales ejes conceptuales. Dada esta interjección teórica, el presente estudio analiza documentos oficiales de políticas públicas llevadas a cabo en ámbito ibérico, para examinar el tratamiento de la idea de futuro en los sistemas educativos. Concretamente, se han estudiado políticas públicas a tres niveles: leyes educativas estatales, currículos de Educación Primaria y políticas institucionales de formación docente, para indagar cuál es la presencia del eje conceptual sobre la imaginación de futuros en estos documentos. Las políticas públicas han sido analizadas mediante el método normativo de análisis de contenido, con una estrategia de muestreo sintáctico, calculando la frecuencia absoluta y relativa de unidades de análisis. Los resultados muestran que hay escasas referencias a la construcción del concepto de futuro en las políticas públicas, y dan a entender que se puede estar desaprovechando la oportunidad de educar para la imaginación de futuros deseables.
In the past few years, an increasing growth has been observed in the demand for premium or specialty chocolates, including single origin, produced exclusively from cocoa beans from selected regions, characterized by a specific chemical profile. A comparative study was made with commercial dark chocolates produced with cocoa from Brazil, Cuba, Madagascar, Mexico, Dominican Republic, São Tomé and Venezuela, including nutritional profile, bioactive compounds, mineral composition, organic acids and methylxanthines. Results presented a significant influence of geographical origin on the chemical profile, based on post-hoc single-step multiple comparison Tukey's HSD test and principal component analysis (PCA). Brazil presented the highest content on PUFA and riboflavin. Brazil and Madagascar presented the highest content on γ-tocopherol, α-tocopherol, antioxidant activity and citric acid. Venezuela presented the highest niacin, Fe and caffeine content. Mexico presented the highest content on fructose. São Tomé presented the highest levels on minerals S and P. However, further investigations should aim for a higher standardization on critical stages, from the selection of varieties to industrial processing.
Industry is a fundamental sector that allows mass production to support a large population. As population grows, many industries produce large amounts of industrial effluents with different pollutants, that must be removed at the industrial wastewater treatment plants, with the consequent production of large amounts of sludge. The present study was conducted to identify and evaluate different sludge treatment/valorisation methodologies, being given priority to the valorisation in detriment of the elimination operations, like incineration or landfill. Therefore, sludges from the wastewater treatment plant of a resin industry, after dehydration operation by a press, were submitted to several valorisation methodologies, such as: application in anaerobic digestion aiming the production of biogas and allowing energy recovery, use in the preparation of adsorbents for the treatment of industrial wastewater, use as cement replacement in mortar production, and application of heterogeneous catalysts to produce biodiesel. The results revealed that all methodologies can be applied as sludge recovery. However, it is possible to conclude that the most promising industrial sludge treatment/recovery hypothesis is anaerobic co-digestion followed by the production of heterogeneous catalysts for biodiesel production.
Background: Hypertension (HT) is highly prevalent and a major risk factor for cardiovascular disease. Over 42% of Portuguese adults have HT. Even though the benefits of antihypertensive (AHT) drugs have been demonstrated, HT control remains inadequate. One major reason is that patients often fail to take their medications as prescribed. This paper aims to determine primary adherence to AHT therapy in newly diagnosed and treated hypertensive patients in Primary Health Care (PHC) units of Lisbon and Tagus Valley Health Region. Methods: This study reports data from a population-based, retrospective, cohort study from patients diagnosed with HT in PHC units of Lisbon and Tagus Valley Region from 1 January to 31 March 2011, with no prior use of AHT drugs. Primary adherence rate was expressed as number of claims records/total number of prescriptions records. Data were collected from SIARS for each patient during a 2-year period. Results: Overall primary adherence rate was 58.5%, increasing with age. Rates were higher for men, living in the Lisbon Metropolitan Area and diagnosed with uncomplicated HT. Drugs acting on the renin-angiotensin system had the highest rates, increasing for fixed-dose combinations and diminishing with the increase of cost for the patient. Conclusions: Overall, almost 1 out of 2 prescribed AHT drugs were not dispensed. Until this study, little was known in Portugal about primary adherence. Our findings imply that the potential benefits of AHT therapy cannot be fully realized in this population.
In this paper, we use the associated production of top-quark pairs (tt¯) with a generic scalar boson (ϕ) at the LHC (pp → tt¯ϕ) to explore the sensitivity of a large set of observables to the sign of the CP mixing angle (α), present in the coupling between the scalar boson and the top quarks. The mass of the scalar boson is set to mϕ = 125 GeV (the Standard Model Higgs boson mass) and its coupling to top-quarks is varied such that α = 0°, 22.5°, 45.0°, 67.5°, 90.0°, 135.0° and 180.0°. Dileptonic final states of the tt¯ϕ system are used (pp → bℓ+νℓb¯ℓ−ν¯ℓbb¯), where the scalar boson is expected to decay according to ϕ → bb¯. A new method to reconstruct the scalar mass, originally designed for the low mass regime is used, improving the resolution of the Higgs mass by roughly a factor of two. A full phenomenological analysis is performed using Standard Model (SM) background and signal events generated with MadGraph5_aMC@NLO, in turn reconstructed using a kinematical fit. The most sensitive CP-observables are selected to compute Confidence Level (CL) limits as a function of the sign of the top quark Yukawa couplings to the ϕ boson. We also explore the sensitivity to interference terms using differential distributions and angular asymmetries. Given the significant difference between the pure scalar (σ0+) and pure pseudo-scalar (σ0−) production cross section values, it is unlikely the tt¯ϕ channel alone will be sensitive to the sign of the CP-mixing angle or interference terms, even at the end of the LHC. Using the b2tt¯ϕ and b4tt¯ϕ variables, exclusion limits at 95% CL for the CP-even and CP-odd components of the top quark Yukawa couplings are expected to be set to κ~ ∈ [-0.698,+0.698] and |κ| ∈ [0.878,1.04], respectively, at the end of the High Luminosity phase of the LHC (HL-LHC) by using the dileptonic decay channel alone.
Sickle cell disease (SCD) is one of the most common genetic conditions worldwide. It can contribute up to 90% of under-5 mortality in sub-Saharan Africa. Clinical manifestations are very heterogeneous, and the intestinal microbiome appears to be crucial in the modulation of inflammation, cell adhesion and induction of aged neutrophils, the main interveners of recurrent vaso-occlusive crisis. Enterocyte injury, increased permeability, altered microbial composition and bacterial overgrowth have all been documented as microbial and pathophysiologic changes in the gut microbiome of SCD patients in recent studies. Our aim was to sequence the bacterial 16S rRNA gene in order to characterize the gut microbiome of Angolan children with SCA and healthy siblings as a control. A total of 72 stool samples were obtained from children between 3 and 14 years old. Our data showed that the two groups exhibit some notable differences in microbiota relative abundance at different classification levels. Children with SCA have a higher number of the phylum Actinobacteria. As for the genus level, Clostridium cluster XI bacteria was more prevalent in the SCA children, whereas the siblings had a higher abundance of Blautia, Aestuariispira, Campylobacter, Helicobacter, Polaribacter and Anaerorhabdus. In this study, we have presented the first microbiota analysis in an Angolan paediatric population with SCD and provided a detailed view of the microbial differences between patients and healthy controls. There is still much to learn before fully relying on the therapeutic approaches for gut modulation, which is why more research in this field is crucial to making this a reality.
Hierarchical BEA zeolite was prepared through desilication or desilication followed by acid treatment. The catalytic performance of BEA zeolite samples was evaluated using Friedel-Crafts acylations with two substrates of different molecular sizes, furan (5.7 Å) and benzofuran (6.9 Å), in the presence of acetic anhydride as acylating agent. The application of the simplified Langmuir-Hinshelwood kinetic model showed that the size of the substrate leads to different catalytic activities, with improved rate constant and turnover frequency (TOF) solely in the presence of benzofuran for both desilicated and further acid treated samples. The mesopores developed during the zeolite treatments have an important role as transportation channels by reducing diffusion limitations. The application of Quantitative Structure–Property Relationships (QSPR) allowed the finding of the most relevant properties of the zeolite and substrate with impact on the catalytic parameters.
The recent implementation of the General Data Protection Regulation (GDPR) establishes a set of formal requirements that reinforce personal data protection, namely, those concerning the collection, treatment, and dissemination of data on research participants. With the application of this new legal provision at the European level, new types of restrictions are emerging, whose nature and reach intensify the tension between demands for privacy and scientific freedom in research. In this article, we take as a reference an ongoing research taking place in Portugal, in the field of Sociology of Health, concerning the consumption of medicines by professionals exposed to high-performance pressure. Our main objective is to identify and analyse the implications of regulatory challenges faced in the research process and how the researchers managed and overcame them. We present a critical narrative that sheds light on the nature of the choices taken while also assessing the practical implications for the operationalisation of the research. We conclude by noting that, despite the benefits that may flow from the application of GDPR, the new requirements regarding the protection of personal data may override the ethical principles of scientific research and strengthen regulatory restrictions on conducting research. In the research concerned, the significant practical implications were indirect access to participants, a more time-consuming process in terms of participant adherence and a temporal discrepancy between the different stages of recruitment.
This work presents a computational fluid dynamic (CFD) analysis of a drag reduction system (DRS) used in a Formula Student competition vehicle, focusing on the interaction between the triple wing elements, as well as on the electrical actuators used to provide movement to the upper two flaps. The S1123 wing profile was chosen, and a 2D analysis of the wing profile was made. The trailing edge was rounded off to conform to Formula Student competition safety rules, resulting in around a 4% decrease in the lift coefficient and around a 12% increase in the drag coefficient for an angle of attack of 12°, compared to the original wing profile. The multi-element profile characteristics are: wing main plate with 4°, first flap 28°, and second flap 60°. To evaluate the wing operation, end plates and electrical linear actuators were added, generating a maximum lift coefficient of 1.160 and drag coefficient of 0.397, which provides around a 10% reduction in lift and a 9% increase in drag compared to the absence of the linear actuators. When activating the DRS, the flap rotation generates about a 78% decrease in the aerodynamic drag coefficient and 53% in the lift coefficient for the minimum aerodynamic drag setting.
Clearly, the construction sector makes a large scale contribution to environmental degradation and urgently needs to change its principles to focus on environmentally sustainable construction. Earth, as a building material, has a potential cradle to cradle life cycle, thus, achieving a circular economy. This material also displays numerous advantages, namely: economic and ecological and as well as the ease of reuse and recyclability. The earth material also registers a high capacity to absorb and release water vapor, which helps to balance the relative humidity and the internal temperature, promoting not only the comfort of occupants but also the quality of the air in buildings. The materials applied in construction hold great influence over the indoor air quality (IAQ). IAQ ranks as such a crucial issue that it appears in the seventeen 2030 Agenda SDGs. As about 90% of our time is spent inside buildings, whether for leisure or work, it is essential to live in spaces with adequate and healthy interior environments. According to the World Health Organization, good air quality represents a basic requirement for life and is a determining factor for the health and well-being of occupants of indoor spaces. In schools, and due to the complex and diversified activities developed there, in addition to adverse health effects, indoor air quality may also have a direct impact on student concentration and performance. Understanding and studying materials, specifically earth mortars, with the ability to capture pollutants and reduce their concentration while helping to regulate the temperature and relative humidity conditions, and student comfort, is thus extremely important. Hence, with the objective of improving the development of construction strategies, this article details and highlights the beginning of the RESpira project.
Background Sickle Cell Anemia (SCA) is a genetic disease caused by the c.20 A > T mutation in HBB gene, generally characterized by sickle erythrocytes, chronic hemolytic anemia, and vaso-occlusive events. This study aimed to investigate genetic modulators of anemia severity, chronic hemolytic rate, and clinical manifestations in pediatric SCA patients from Angola, where the disease is a severe public health problem. Methods and Results The study was conducted on 200 SCA children living in Luanda or Caxito province. Their clinical phenotype was collected from patients’ hospital records. Hematological and biochemical phenotypes were characterized in steady state condition. Twelve polymorphic regions in VCAM1, CD36 and NOS3 genes were genotyped using PCR, RFLP, and Sanger sequencing. CD36 gene promoter variants showed a significant impact on anemia severity. Particularly, the rs1413661_C allele was associated with lower hemoglobin levels, and increased number of hospitalizations and transfusions. This is the first report associating this SNP with SCA phenotypic heterogeneity. Moreover, the rs1041163_C allele in VCAM1 was associated with lower LDH levels; inversely the rs2070744_C allele in NOS3 was related with higher LDH levels and number of hospitalizations, being a risk factor for increased hemolytic rate. Conclusion This study highlights, for the first time in the Angolan population, the importance of the genetic modifiers of vascular cell adhesion and nitric oxide metabolism in SCA pediatric phenotypic variability.
Objective - The COVID-19 pandemic led to an abrupt transition to online classes in higher education, with no consideration for the specific students' conditions in Portugal and other countries. Therefore, this study aims to assess the students' perspectives on online learning classes during the lockdown in 2020. Methodology/Technique - The analysis is based on 2,107 valid answers from students of seven Portuguese higher education institutions that took synchronous online classes. Principal component analysis and binary logistic regression were the main quantitative methods used. Findings – This study identified five factors that, in all cases, significantly explain the students' perspective on the transition to online classes. These factors include not only pedagogical matters (teachers' overall quality) but also elements related to personal or motivational students' characteristics (performance and autonomy; constraints and obstacles to socialization; self-confidence while attending online classes) and technological issues (Internet access conditions). Notwithstanding, self-confidence is not a relevant factor for students with technical limitations concerning infrastructural matters. Novelty - Besides the contributions of this study, it is important to emphasize its relevance by combining the critical success factors in distance learning with different demographic variables, which are usually less explored by this literature. Notwithstanding, less robust and inconsistent results were found for those variables. Type of Paper: Empirical JEL Classification: I18, I23, I28. Keywords: COVID-19; emergency remote teaching; higher education; technical infrastructures; students' perspective. Reference to this paper should be made as follows: Albuquerque, F; Santos, P.G.D; Martinho, C. (2022). Overall Satisfaction with the Emergency Remote Teaching during the COVID-19 Pandemic from the Perspective of Higher Education Students in Portugal, J. Mgt. Mkt. Review, 7(3), 116 – 128.
For companies to stand out in increasingly competitive, dynamic and global markets, they must have customer satisfaction goals, create value through their processes, products and services and also aim for innovation. In this context, computer sciences combined with engineering processes constitutes a powerful way for companies to be able to improve process management, to interact with such markets in an efficient and effective way. The main objective of this article is to use Arena simulation software, to quantitatively predict the impact of improvements applied in metal surface treatment processes, based on tools to support Lean thinking. A case study in a Portuguese company in the metalworking sector is presented, in which it is verified that the proposed improvements in terms of the factory layout and resource management, suggested by the comparison between simulations of the current state of the company and the improved one, streamline the processes of finishing in metals, namely zinc coating and lacquering which prevent the occurrence of oxidation and the consequent corrosion of the base metals, by adding other metals and materials to their surface, which adhere and protect it. Through the results obtained, it is concluded that the reduction of waiting times and transport of stocks without production and of work-in-progress, as well as the increase of the productive capacity, make the company more able to guarantee the satisfaction of the requirements of its customers and improve its positioning in the market compared to its competitors.
We described a dinosaur tracksite found in the uppermost part of the Areia do Mastro Formation (lowermost Barremian, Lower Cretaceous), located at 1.5 km north of Cabo Espichel (Sesimbra, Portugal). The studied tracks are distributed in a heavily trampled limestone bed which crops out alongside the rocky beach. The studied trampled surface is highly dinoturbated, 541 tracks assigned to sauropods, ornithopods and theropods were identified. The majority of footprints (336) were produced by the herbivores. The dinoturbated level is a micritic nodular limestone, deposited in a very shallow subtidal to intertidal lagoon environment. Due to the intense bioturbation and limited exposed area, it is difficult to clearly define trackways, but the tracks can provide information about the producers and their behaviours. It is inferred that dinosaurs crossed this area at different times; the herbivores (sauropods and ornithopods) may possibly used the coastal area as passage between feeding spots, while carnivores frequented the area to hunt in groups or individually.
A bstract We present a comprehensive study on Higgs pair production in various archetypical extended Higgs sectors such as the real and the complex 2-Higgs-Doublet Model, the 2-Higgs-Doublet Model augmented by a real singlet field and the Next-to-Minimal Supersymmetric extension of the Standard Model. We take into account all relevant theoretical and experimental constraints, in particular the experimental limits on non-resonant and resonant Higgs pair production. We present the allowed cross sections for Standard Model (SM)-like Higgs pair production and the ranges of the SM-like Yukawa and trilinear Higgs self-coupling that are still compatible with the applied constraints. Furthermore, we give results for the pair production of a SM-like with a non-SM-like Higgs boson and for the production of a pair of non-SM-like Higgs bosons. We find that di-Higgs production in the models under investigation can exceed the SM rate substantially, not only in the non-resonance region but also due to resonant enhancement. We give several benchmarks with interesting features such as large cross sections, the possibility to test CP violation, Higgs-to-Higgs cascade decays or di-Higgs production beating single Higgs production. In all of our benchmark points, the next-to-leading order QCD corrections are included in the large top-mass limit. For these points, we found that, depending on the model and the Higgs pair final state, the corrections increase the leading order cross section by a factor of 1.79 to 2.24. We also discuss the relation between the description of Higgs pair production in an effective field theory approach and in the specific models investigated here.
Background We aimed to synthesize the evidence on the efficacy and safety of different treatment regimens for latent tuberculosis infection (LTBI) in children and adolescents. Methods A systematic review with network meta-analysis was performed (CRD142933). Searches were conducted in Pubmed and Scopus (Nov-2021). Randomized controlled trials comparing treatments for LTBI (patients up to 15 years), and reporting data on the incidence of the disease, death or adverse events were included. Networks using the Bayesian framework were built for each outcome of interest. Results were reported as odds ratio (OR) with 95% credibility intervals (CrI). Rank probabilities were calculated via the surface under the cumulative ranking analysis (SUCRA) (Addis-v.1.16.8). GRADE approach was used to rate evidence's certainty. Results Seven trials (n = 8,696 patients) were included. Placebo was significantly associated with a higher incidence of tuberculosis compared to all active therapies. Combinations of isoniazid (15–25 mg/kg/week) plus rifapentine (300–900 mg/week), followed by isoniazid plus rifampicin (10 mg/kg/day) were ranked as best approaches with lower probabilities of disease incidence (10% and 19.5%, respectively in SUCRA) and death (20%). Higher doses of isoniazid monotherapy were significantly associated to more deaths (OR 18.28, 95% ICr [1.02, 48.60] of 4–6 mg/kg/day vs. 10 mg/kg/3x per week). Conclusions Combined therapies of isoniazid plus rifapentine or rifampicin for short-term periods should be used as the first-line approach for treating LTBI in children and adolescents. The use of long-term isoniazid as monotherapy and at higher doses should be avoided for this population.
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3,073 members
Maria da Luz Antunes
  • Escola Superior de Tecnologia da Saúde de Lisboa
Amin Karmali
  • Centro de Investigação em Engenharia Química e Biotecnologia
Catarina Tomás
  • Escola Superior de Educação
Lina Vieira
  • Departamento das Ciências e Tecnologias das Radiações e Biossinais da Saúde
Carla Costa Lança
  • Escola Superior de Tecnologia da Saúde de Lisboa
Estrada de Benfica 529, 1549-020, Lisbon, Portugal
Head of institution
Elmano Margato
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