Coleções gerais - Artigos em revistas internacionais
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- Investigação qualitativa: em que ponto estamos?Publication . Brandão, Catarina; Ribeiro, Jaime; Costa, António Pedro
- Planning a health promotion program: Mobile app gamification as a tool to engage adolescentsPublication . Pernencar, Cláudia ; Sousa, Pedro; Frontini, Roberta; Martinho, Ricardo; Runte, Daniel; Mendes, Denis; Carvalho, MiguelOver the past decade, the World Health Organization (WHO) has been alerting about the existing overweight prevailing among the adolescents’ group. This group is considered a nutritional risk group mainly because of less correct eating patterns and misbehaviors towards physical activity. To prevent obesity within this risk group, we are working on a mobile application involving gamification techniques. This article presents the preliminary results of a design study for this app, and explores possible design guidelines and processes based on results achieved in preliminary user interface and experience tests.
- Modelling of Structures under Seismic, Impact, and Shock VibrationsPublication . Bhatti, Abdul Qadir; Ahmad, Naveed; Pinheiro Rodrigues, Hugo Filipe; Brandonisio, Giuseppe
- Obtaining of Biologically Soluble Membranes Based on Polymeric Nanofibres and Hydroxyapatite of CalciumPublication . Daulbayev, Ch.; Mitchell, G.; Zakhidov, A.; Sultanov, F.; Mansurov, Z.In this paper, the possibility of obtaining a synthetic hydroxyapatite of calcium from a biological waste material is shown. The characteristics influencing the synthesis process are studied. Based on the results of the X-ray analysis and the obtained electron microscope images, it can be concluded that the synthesized HAP has a Ca/P ratio of 1.5 and with crystals with an average size of 2 microns. In work, experiments on obtaining biologically soluble films based on nanoscale polymer fibers and calcium hydroxyapatite were carried out. As a result, the main parameters of the process for the electroforming of nano-sized fibers with HAP are determined. The proposed method allows the laying of strictly directed nanofibers from a polymer with a diameter of 50 to 500 nm. The use of different types of electrodes makes it possible to vary the size of nanofibers. The characteristics such as solution viscosity, high voltage and optimum parameters were selected, which allowed obtaining films from biologically soluble polymer nanofibers and HAP. Also, experiments were conducted to introduce medicines into the film structure.
- Dermoscopic assisted diagnosis in melanoma: Reviewing results, optimizing methodologies and quantifying empirical guidelinesPublication . Lee, Huei Diana; Mendes, Ana Isabel; Spolaôr, Newton; Oliva, Jefferson Tales; Parmezan, Antonio Rafael Sabino; Wu, Feng Chung; Fonseca-Pinto, RuiEarly diagnosis is still the most important factor to deal with skin cancer, a disease that challenges physicians and researchers. It has benefited from computer-aided diagnosis methods that successfully combine dermoscopy, Digital Image Processing, and Machine Learning techniques. This paper aims to approximate medical professionals working with dermoscopy to these methods, to join the challenge of melanoma early detection. Accordingly, a proposal for extracting, selecting and combining texture and shape features from dermoscopic images is presented. The Feature Selection task is added to the learning process to potentiate the quality of classification models. Three classical Machine Learning algorithms were applied to differentiate melanoma from non-melanoma images. The models are evaluated by standard performance measures and a multi-criteria decision analysis method. This is the first time such method is used in melanoma diagnosis. As a result, we found a decision tree that performs well and allows the explicit representation and analysis of the knowledge learned from the images. In addition, the competitiveness of our decision models in comparison with literature approaches reviewed in this work encourages further applications of Machine Learning and Feature Selection to assist computer-aided diagnosis.
- Sustainable development in Portuguese higher education institutions from the faculty perspectivePublication . Leal, Susana; Azeiteiro, Ulisses M.; Aleixo, Ana MartaHigher education institutions play a fundamental role and have great responsibility in promoting sustainability and achieving sustainable development goals. It is therefore essential to study the teacher's perceptions of incorporating sustainability since they are responsible for promoting competences and preparing citizens to respond with solutions to future challenges. The aim of this research is to analyse the perceptions of sustainability held by teachers at Portuguese public higher education institutions. A descriptive and exploratory study was conducted by administering an online questionnaire. The sample is made up of 444 teachers from different Portuguese public higher education institutions (54.1% women and 45.9% men). The results show that while most teachers believe higher education institutions promote the integration of sustainability in their activities, only 16% consider that sustainable development is holistically integrated in the institutions' different activities. About 30% of the teachers report that they largely or extensively integrate sustainable development in their curricular units, but only 20% of them state that higher education institutions provide regular or systematic training in SD. Teachers prefer to increase students' sustainable development education through conferences, seminars, or research projects. Almost 90% of teachers are concerned about climate change or the environment, but only 40% or less engage in sustainable development-related activities. Four clusters are also identified, representing teachers' different perceptions of the higher education institutions' promotion of sustainability, teachers' participation in sustainable development issues and concerns about climate change. Although teachers feel that sustainability is starting to be integrated in higher education institutions, this is not done holistically; moreover, differences are found between teachers in polytechnics and universities and between different scientific areas.
- Fundamental solution of the time-fractional telegraph Dirac operatorPublication . Ferreira, Milton; Rodrigues, M. Manuela; Vieira, Nelsonn this work, we obtain the fundamental solution (FS) of the multidimensionaltime-fractional telegraph Dirac operator where the 2 time-fractional derivatives oforders𝛼∈]0,1]and𝛽∈]1,2]are in the Caputo sense. Explicit integral and seriesrepresentation of the FS are obtained for any dimension. We present and discusssome plots of the FS for some particular values of the dimension and of the frac-tional parameters𝛼and𝛽. Finally, using the FS, we study some Poisson and Cauchyproblems
- Are the sustainable development goals being implemented in the Portuguese higher education formative offer?Publication . Aleixo, Ana Marta; Azeiteiro, Ulisses M.; Leal, SusanaPurpose: The study aims to examine the vertical integration of the sustainable development goals (SGDs) in Portuguese public higher education institutions, namely, at the level of undergraduate and master’s degrees, and the extent to which Portuguese higher education institutions (HEI) are preparing for the United Nations’ call to promote SDGs. Design/methodology/approach: A content analysis of the designations and objectives of the 2,556 undergraduate and master’s degrees (in 33 Portuguese public higher education institutions) was done to determine whether they promote at least one SDG. Findings: The results show that 198 courses directly address at least one SDG; on average, each higher education institution (HEI) has six courses that explicitly address at least one SDG; universities have more courses in SDG areas than in polytechnics; more master’s degrees embrace SDGs than undergraduate degrees; and most of the courses addressing SDGs are from the social sciences and humanities areas and from natural and environmental sciences. Originality/value: This paper serves to raise the awareness of Portuguese HEIs of their role and responsibility in furthering SGDs.
- A fibre flexure-shear model for seismic analysis of RC-framed structuresPublication . Ceresa, Paola; Petrini, Lorenza; Pinho, Rui; Sousa, RomainWhilst currently existing modelling approaches of reinforced concrete behaviour allow a reasonably accurate prediction of flexural response, the determination of its shear counterpart needs further developments. There are various modelling strategies in literature able to predict the shear response and the shear-flexure coupling under monotonic loading conditions. However, very few are the reported models that have demonstrated successful results under cyclic loading, as in the seismic load case. These considerations lead to this research work focused on the development of a flexure-shear model for reinforced concrete beam-column elements. A reliable constitutive model for cracked reinforced concrete subjected to cyclic loading was implemented as bi-axial fibre constitutive model into a two-dimensional Timoshenko beam-column element. Aim of this research work is to arrive at the definition of a numerical model sufficiently accurate and, at the same time, computationally efficient, that will enable implementation within a Finite Element package for nonlinear dynamic analysis of existing non seismically designed RC structures that are prone to shear-induced damage and collapse.
- Comparative structural response of two steel bridges constructed 100 years apartPublication . Varum, Humberto; Sousa, Romain; Delgado, Walter; Fernandes, Catarina; Costa, Aníbal; Jara, José; Jara, Manuel; Álvarez, JesúsThis paper presents a comparative numerical analysis of the structural behaviour and seismic performance of two existing steel bridges, the Infiernillo II Bridge and the Pinhão Bridge, one located in Mexico and the other located in Portugal. The two bridges have similar general geometrical characteristics, but their construction is separated by one hundred years. 3D structural models of both bridges were developed and analyzed for various load cases and several seismic conditions. The results of the comparative analysis between the two bridges are presented in terms of natural frequencies and corresponding vibration modes, maximum stresses in the structural elements and maximum displacements. The study aimed at determining the influence of one century period in material properties, transverse sections and expected behaviour of two quite similar bridges. In addition, the influence of the bearing conditions in the global response of the Pinhão Bridge was evaluated.
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