2,835 research outputs found

    In and out and out again: The travails of Brazil as a security provider in Africa

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    The story of Brazil as a contemporary security actor in Africa can prove a peculiar one. Marked by quick gains and an equally quick recognition over a short period of time, it has also been followed by an equally quick turnaround which has led, as of 2020, to a visible disengagement on the ground. We explore the main travails in this domain, which have compromised much of the gains previously obtained throughout the continent. The chapter begins with a general balance of the progress achieved between 2003 and 2016, followed by the highlights of the recent downturn. We then analyze a specific sub-area, namely, the inroads carried out at the defence industry level, in order to showcase the promises and contradictions often associated to what the country has offered across the Atlantic. We conclude by presenting some opportunities for a new pickup of Brazilian interest in the middle and long run

    Averaging methods for design of spacecraft hysteresis damper

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    This work deals with averaging methods for dynamics of attitude stabilization systems. The operation of passive gravity-gradient attitude stabilization systems involving hysteresis rods is described by discontinuous differential equations. We apply recently developed averaging techniques for discontinuous system in order to simplify its analysis and to perform parameter optimization. The results obtained using this analytic method are compared with those of numerical optimization.This research is supported by the Portuguese Foundation for Science and Technologies (FCT), the Portuguese Operational Programme for Competitiveness Factors (COMPETE), the Portuguese Strategic Reference Framework (QREN),and the European Regional Development Fund (FEDER)

    Estudo comparativo da artrodese posterolateral e PLIF no tratamento da espondilolistesis degenerativa grau I ou II ? análise de 124 casos

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    Objetivo: Posterior Lumbar Interbody Fusion (PLIF) ou artrodese posterolateral (APL) são técnicas cirúrgicas válidas na espondilolistese degenerativa. Alterações biomecânicas no nível adjacente à artrodese aceleram alterações degenerativas. Na literatura discute-se o tratamento adequado. Este estudo comparativo avalia clínica, taxa de fusão, complicações, alterações degenerativas e instabilidade no nível adjacente. Material e Métodos: Retrospectivamente foram analisadas espondilolisteses degenerativas grau I e II de Meyerding tratadas com PLIF ou APL de Janeiro 2000 a Dezembro 2010 num total de 124 doentes, 45 PLIF e 79 APL. Recorreu-se à escala visual analógica (VAS), Oswestry Disability Index (ODI) e Short Form-36 (SF-36). No PLIF foi determinada artrodese por estabelecimento de pontes ósseas estáveis. A instabilidade na APL foi definida quando osteolise adjacente aos parafusos, deslizamento ou angulação no nível da fusão. Resultados: O follow-up foi 4.5±2.7 e 3.9±2.6 anos (1-11 anos) no PLIF e APL, respectivamente. Ocorreu fusão em 93.3% no PLIF e 74.7% na APL (p=0.008). O PLIF apresenta superioridade no VAS pós-operatório (p=0.01) e variação geral (p=0.002). O ODI pós-operatório no PLIF foi menor (p<0.001) e 2.2% permanecem com disfunção severa comparativamente com 19% na APL. O PLIF é superior em escalas do SF-36: Função Física (p=0.034), Limitação Emocional (p=0.037), Função Social (p=0.05) e Saúde Geral (p=0.02). A taxa de complicações foi 4.4% no PLIF e 12.6% na APL (p=0.2). Ambas as técnicas desenvolveram doença do disco adjacente. Conclusões: Em ambos os grupos verifica-se melhoria da qualidade de vida, no entanto, a médio prazo o PLIF mostra superioridade. Instabilidade pré-operatória pode ser indicativa da eleição de PLIF

    Fabrication of Poly(Glycerol Sebacate)-Poly(ε-Caprolactone) Extrusion-Based Scaffolds for Cartilage Regeneration

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    Acknowledgements: This research was supported by the European Regional Development Fund (FEDER), through COMPETE2020 under the PT2020 program (POCI-01-0145-FEDER-023423), by the Portuguese Foundation for Science and Technology (UID/Multi/04044/2013) and Centro2020 PAMI - ROTEIRO/0328/2013 (Nº 022158).Cartilage related diseases are on the top list concerns of the World Health Organization, being the prevention of articular cartilage degeneration a major health matter for which there are few effective solutions. Using an extrusion-based approach and a polyester elastomer it was aimed to produce 3D structures with controlled architecture and with closer mimicry to cartilage native tissue. The obtained constructs demonstrated high reliability, being the addition of poly (glycerol sebacate) a procedure to enhance the properties of the constructs.info:eu-repo/semantics/publishedVersio

    How much does it cost to implement a community-based walking football programme for patients with type 2 diabetes?

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    ObjectivesThe current study analysed the implementation costs of a community-based walking football exercise programme for patients with type 2 diabetes.MethodsThe direct costs of a community-based walking football programme for middle-aged and older male patients with type 2 diabetes, designed and tested in Porto (Portugal), were calculated from the payer's perspective. One season of this programme consists of three sessions per week (60 min per session) for nine months (October to June). Cost calculations were based on two groups of 20 patients and included the sports infrastructure and equipment, human resources, pre-exercise clinical evaluation, medical equipment, technical training and other consumable costs. An economic depreciation of 1 year using the linear method for sports and electronic materials was considered. Cost analysis dated December 2021 and is expressed in international dollars ().ResultsThisprogrammewasestimatedtohaveatotalimplementationcostof).ResultsThis programme was estimated to have a total implementation cost of 22 923.07; 2547.01/month;2547.01/month; 573.08/patient; 106.13/session;106.13/session; 63.68/patient/month and $5.31/patient/session.ConclusionA community-based walking football programme for patients with type 2 diabetes is affordable and can be scaled up by local communities to promote physical activity and manage type 2 diabetes with the involvement of multiple stakeholders such as the football clubs, municipalities and primary healthcare units.This work was supported by the Portuguese Foundation for Science and Technology within the scope of projects UIDB/04750/2020 and LA/P/0064/2020. AB is supported by the Portuguese Foundation for Science and Technology [grant number SFRH/BD/136702/2018]

    The Importance of Design in the Development of a Portable and Modular Iot-Based Detection Device for Clinical Applications

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    The integration of human factors engineering methods within the medical device design and development process has been highlighted by international standards organizations. Such methods are contributing to the development of safer medical devices, more suitable to users' needs. Errors during device operation might hamper effective patient diagnosis and treatment, or eventually lead to injury or death. Thus, the designing process of a medical device is indeed crucial to user experience and safety operation. This paper presents a human-centred design analysis of a novel IoT-based screening prototype (iLoF) based on Artificial Intelligence algorithms built-in in a patented-photonics system developed by a deep tech startup. The influence of the design process during the development of the prototype was addressed, based on a human-centred design methodology and considering the device's application environment. iLoF's prototype on-field applicability was evaluated considering a single case-study carried out at one of the main hospitals in Portugal through interviews to ten healthcare professionals with high experience in laboratorial testing. A benchmark assessment and a comparison matrix along with the market products are also presented to fully understand the technology state and to find new solutions that can influence iLoF's product development. © Published under licence by IOP Publishing Ltd

    Correlates of changes in BMI of children from the Azores islands

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    Objective: To model changes in body mass index (BMI), including its stability, and to investigate the association between physical activity, 1-mile run/walk and levels of gross motor coordination and BMI during 5 consecutive years. Design: A longitudinal study of children 6 years of age at baseline followed at annual intervals over 5 years. Subjects: A total of 285 children (143 boys and 142 girls) were enrolled in grade 1 (age 6 years) and followed through grade 5 (age 10 years). Measurements: BMI was recorded and physical activity was assessed by questionnaire, aerobic fitness was evaluated with the 1-mile run/walk and gross motor coordination was measured with the KTK test battery (Korperkoordination test fur Kinder). Multilevel modelling techniques were for the primary analysis. Results: Changes in BMI showed similar curvilinear trends in boys and girls, with ample inter-individual crossing trajectories that is, low tracking. Longitudinal changes in physical activity (PA) and aerobic fitness were not significantly associated with BMI-changes during the 5 years. Children who were more proficient in their motor coordination showed lower values of BMI during the 5 years. Conclusions: BMI trajectories of both boys and girls show low tracking of BMI-values. Considerable inter-individual variation exists both in baseline BMI-values and changes (velocity and acceleration) over time. PA and fitness were not associated with BMI-changes, but gross motor function was negatively associated with BMI-changes. No gender-specific associations were found. If confirmed in other populations these observations could be translated in the promotion of physical activities that improve gross motor function in children aged 6-10 years. This seems to be of major importance for the physical education curriculum of primary school children

    To practice or not to practice? Designing higher education curriculum to boost employability

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    One important dimension of Higher education curriculum design pertains to the inclusion of internships in study programmes. These have been generally conceptualized as learning experiences capable of bridging theoretical knowledge and hands-on experiences. The underlying pedagogical relevance is based on the premise that internships create the possibility of contextualized learning, fostering both professional growth and students’ self-esteem and pro-activity (Little, 2006). Interns are provided with the opportunity of early networking, as they enrol in practical activities and professionally interact with other people, besides their academic teachers and their graduate colleagues (Alpert, Heaney, & Kuhn, 2009; Weible, 2009). Research concerning internships has extensively reported the overwhelming positive effect of internships. Nevertheless, a more recent trend in literature has argued that little has been said concerning the relationship between internships and graduate employment or employability. Wilton (2012), for example, argues that more needs to be understood about the characteristics and specificities of internships and the extent to which such characteristics are capable of overcoming the current concern over the increase of graduates’ unemployment rates. Research conducted on the Portuguese case based on a database of 1,168 study programmes of first cycle degrees sough to redress this gap. Besides demonstrating that study programmes which include internships (cooperative education) tend to generate lower levels of unemployment than those that do not include internships, this research has suggested that the nature and structure of internships significantly impacts on graduate unemployment rates. In specific, mandatory internships tend to outperform their optional counterpart in reducing graduate unemployment levels. Moreover, thin sandwich courses also seem to be more beneficial than thick sandwich courses, suggesting that expanding and diversifying internships throughout the curriculum can reduce graduate unemployment rates. These results strongly suggest that it is not (only) the internship learning experience per se that makes the difference considering graduate employability, but (also) the way those internship experiences are organized along the study programme. This poster is, thus, focused on the nature and structure of internships, assessing their implications for higher education curriculum design. It does so by exploring the perspectives of the main stakeholders involved in internships regarding their motivations; required efforts; and expected outcomes. Empirically, the poster is based on the content analysis of semi-structured individual interviews to units coordinators and also focus groups conducted with coordinators of study programmes; internship supervisors (both academics and employers); and also interns. Qualitative analysis has been sustained by the main learning models traditionally used in research on work-based learning and aims at identifying a set of principles related with internships design, and modes of embedding them along an entire course, which may contribute to the development of graduates’ employability. Reported findings may constitute an important primer for reflection on the design of pedagogical strategies that maximize the contextual learning outputs of internships in a more systematic way, being particularly relevant for leading academics, namely those involved in curriculum design

    Numerical simulation of strongly nonlinear and dispersive waves using a Green-Naghdi model

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    We investigate here the ability of a Green-Naghdi model to reproduce strongly nonlinear and dispersive wave propagation. We test in particular the behavior of the new hybrid finite-volume and finite-difference splitting approach recently developed by the authors and collaborators on the challenging benchmark of waves propagating over a submerged bar. Such a configuration requires a model with very good dispersive properties, because of the high-order harmonics generated by topography-induced nonlinear interactions. We thus depart from the aforementioned work and choose to use a new Green-Naghdi system with improved frequency dispersion characteristics. The absence of dry areas also allows us to improve the treatment of the hyperbolic part of the equations. This leads to very satisfying results for the demanding benchmarks under consideration

    Phase diagram of the classical Heisenberg antiferromagnet on a triangular lattice in applied magnetic field

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    The Heisenberg antiferromagnet on a two-dimensional triangular lattice is a paradigmatic problem in frustrated magnetism. Even in the classical limit, its properties are far from simple. The "120 degree" ground state favoured by the frustrated antiferromagnetic interactions contains a hidden chiral symmetry, and supports two distinct types of excitation. And famously, three distinct phases, including a collinear one-third magnetisation plateau, are stabilised by thermal fluctuations in applied magnetic field. The questions of symmetry-breaking raised by this model are deep and subtle, and after more than thirty years of study, many of the details of its phase diagram remain surprisingly obscure. In this paper we use modern Monte Carlo simulation techniques to determine the finite-temperature phase diagram of the classical Heisenberg antiferromagnet on a triangular lattice in applied magnetic field. At low to intermediate values of magnetic field, we find evidence for a continuous phase transition from the paramagnet into the collinear one-third magnetisation plateau, belonging to the three-state Potts universality class. We also find evidence for conventional Berezinskii-Kosterlitz-Thouless transitions from the one-third magnetisation plateau into the canted "Y-state", and into the 2:1 canted phase found at high fields. However, the phase transition from the paramagnet into the 2:1 canted phase, while continuous, does not appear to fall into any conventional universality class. We argue that this, like the chiral phase transition discussed in zero field, deserves further study as an interesting example of a finite-temperature phase transition with compound order-parameter symmetry. We comment on the relevance of these results for experiments on magnetic materials with a triangular lattice.Comment: 15 pages, 12 figures, very minor change
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