Os italianos na Madeira : séculos XV-XVI

A presença de italianos na Madeira surge como consequência da sua forte implantação na península e do seu manifesto empenho na revelação do novo mundo; em Portugal e Castela estes procuraram os portos ribeirinhos de maior animação comercial, e aí se evidenciaram como mercadores, mareantes e banqueiros. Destes destacam-se os oriundos de Génova, Veneza e Florença, cidades de grande animação comercial e marítima, que abriram, nos locais de fixação, novas vias para o comércio com o mercado mediterrâneo. A partir de Lisboa ou Cádiz estes intervêm, primeiro, no comércio peninsular, e, depois, nas navegações e actividades de troca no espaço atlântico. Esta última situação torna-se evidente com a intervenção de António de Noli e Alvise de Cadamosto. [...

Editorial

Caros (as) colegas e amigos (as),A renovação é fonte de vida e chegou a hora de passar o testemunho como presidente da direcção da Sociedade Portuguesa de Radiologia e Medicina Nuclear (SPRMN), a qual tenho servido nos últimos dezasseis anos, os últimos quatro como presidente, o que muito me honrou.Foi uma experiencia de vida fantástica, embora com muitos desafios e contrariedades, nomeadamente condicionado pelos tempos conturbados e pelas vicissitudes da crise económica e financeira do nosso país nos últimos quatro anos, que obviamente se reflectiram na vida profissional de todos nós, bem como no funcionamento da nossa Sociedade.Na tentativa de encontrar soluções para problemas que nunca se tinham colocado à radiologia portuguesa foi promovido pela SPRMN o debate “Radiologia em 2013 - Desafios e Oportunidades”, que culminou na formação de uma associação profissional dos radiologistas portugueses, que esperamos possa ajudar na resolução dos nossos problemas profissionais, atendendo que a SPRMN é uma sociedade com propósitoscientíficos

Vertical stability of circular orbits in relativistic razor-thin disks

During the last few decades, there has been a growing interest in exact solutions of Einstein equations describing razor-thin disks. Despite the progress in the area, the analytical study of geodesic motion crossing the disk plane in these systems is not yet so developed. In the present work, we propose a definite vertical stability criterion for circular equatorial timelike geodesics in static, axially symmetric thin disks, possibly surrounded by other structures preserving axial symmetry. It turns out that the strong energy condition for the disk stress-energy content is sufficient for vertical stability of these orbits. Moreover, adiabatic invariance of the vertical action variable gives us an approximate third integral of motion for oblique orbits which deviate slightly from the equatorial plane. Such new approximate third integral certainly points to a better understanding of the analytical properties of these orbits. The results presented here, derived for static spacetimes, may be a starting point to study the motion around rotating, stationary razor-thin disks. Our results also allow us to conjecture that the strong energy condition should be sufficient to assure transversal stability of periodic orbits for any singular timelike hypersurface, provided it is invariant under the geodesic flow.Comment: 13 pages, 4 figures; Accepted for publication in Physical Review

Chaos around the superposition of a black-hole and a thin disk

Motivated by the strong astronomical evidences supporting that huge black-holes might inhabit the center of many active galaxies, we have studied the integrability of oblique orbits of test particles around the exact superposition of a black-hole and a thin disk. We have considered the relativistic and the Newtonian limits. Exhaustive numerical analyses were performed, and bounded zones of chaotic behavior were found for both limits. An intrinsic relativistic gravitational effect is detected: the chaoticity of trajectories that do not cross the disk.Comment: Revtex, 13 pages, 3 figure

Characteristics of the dairy goat primary sector at the Rio de Janeiro State, Brazil.

A survey was done based on 19 goat shepherds at counties of Centre-highlands, Northern and North-western regions of the Rio de Janeiro State and at the county of Pedra Dourada, Zona da Mata region, State of Minas Gerais. We aimed to characterise the primary sector of the goat milk production chain settled at those regions. Therefore, questionnaires were applied in order to depict profiles of the shepherds, their families, the role of the wife in the activity, the resources available, dependence on income generated by the activity, and how producers administrate their business. Farms were distributed in five strata according to the following daily milk production averages and standard deviations: 8.8 ± 0.9, 15.7 ± 3.9, 22.6 ± 2.7, 34.4 ± 3.4, and 183.8 ± 54.2 L/d. Approximately 42% of the interviewed producers conducted their activities according to a household production model and the income earned was exclusively from the dairy goat husbandry. Sons and daughters performed an important role in the business (27.80%), but most of them (62.73%) worked out at non farm activities. The percentage of wives that worked directly in the activity (@47%) indicated that it could contribute to gender equity in the rural environment. Most of the production systems (63.16%) presented positive gross margins. We have noticed, however, that shepherds perceived only the business gross margin and that the most accurate registries taken were those related to revenues. In general, producers of the higher strata were favoured by their larger production scale, but asymptotic behaviours for costs and amounts invested in animals, equipments and buildings were observed. These characteristics should be considered when policies related to the dairy goat primary sector have to be planned

Discovery of Transport Operations from Geolocation Data

Os dados de geolocalização identificam a localização geográfica de pessoas ou objetos e são fundamentais para empresas que dependem de veículos, como empresas logísticas e de transportes. Com o avanço da tecnologia, a recolha de dados de geolocalização tornou-se cada vez mais acessível e económica, gerando novas oportunidades de inteligência empresarial. Este tipo de dados tem sido utilizado principalmente para caracterizar o veículo em termos de posicionamento e navegação, mas também pode ter um papel preponderante na avaliação de desempenho em relação às atividades e operações executadas. A abordagem proposta consiste numa metodologia com várias etapas que recebe dados de geolocalização como entrada e permite a análise do processo de negócio no final. Em primeiro lugar, a preparação dos dados é aplicada para lidar com uma série de questões relacionadas com ruído e erros nos dados. Depois, a identificação dos eventos estacionários é realizada com base nos estados estacionários dos veículos. Em seguida, é realizada a inferência de operações com base numa análise espacial, que permite descobrir os locais onde os eventos estacionários ocorrem com frequência. Finalmente, as operações identificadas são classificadas com base nas suas características, e a sequência de eventos pode ser estruturada. A aplicação de técnicas de process mining é então possível e a consequente extração de conhecimento do processo. As etapas da metodologia também podem ser utilizadas separadamente para enfrentar desafios específicos, dando mais flexibilidade à sua aplicação. Três estudos de caso distintos são apresentados para demonstrar a eficácia e transversalidade da solução. Fluxos de dados de geolocalização em tempo real de autocarros de duas redes distintas de transporte público são usados para demonstrar a detecção de operações relacionadas com os veículos e comparar as distintas abordagens propostas por este trabalho. As operações dos autocarros produzem uma sequência estruturada de eventos que descreve o comportamento dos mesmos. Esse comportamento é mapeado por meio da aplicação de técnicas de process mining, para descobrir oportunidades de análise e gargalos no processo. Complementarmente, os dados de geolocalização de uma empresa de logística internacional são explorados para a monitorização de processos logísticos, nomeadamente para detecção de operações de logística em tempo real, demonstrando a eficácia da solução proposta para resolver problemas específicos da indústria. Os resultados deste trabalho revelam novas possibilidades no uso de dados de geolocalização e o seu potencial para gerar conhecimento acerca do processo. A exploração de dados de geolocalização nos contextos logísticos e de transportes públicos apresenta-se como uma oportunidade para melhorar a monitorização e gestão das operações baseadas em veículos. Isso pode originar melhorias na eficiência do processo e, consequentemente, maior lucro e melhor qualidade do serviço.Geolocation data identifies the geographic location of people or objects, and is fundamental for businesses relying on vehicles such as logistics and transportation. With the advance of technology, collecting geolocation data has become increasingly accessible and affordable, raising new opportunities for business intelligence. This type of data has been used mainly for characterizing the vehicle in terms of positioning and navigation, but it can also showcase its performance regarding the executed activities and operations. The proposed approach consists on a multi-step methodology that receives geolocation data as an input and allows the analysis of the business process in the end. Firstly, the preparation of the data is applied to handle a number of issues related to outliers, data noise, and missing or erroneous information. Then, the identification of stationary events is performed based on the motionless states of the vehicles. Next, the inference of operations based on a spatial analysis is performed, which allows the discovery of the locations where stationary events occur frequently. Finally, the identified operations are classified based on their characteristics, and the sequence of events can be structured into an event log. The application of process mining techniques is then possible and the consequently extraction of process knowledge. The steps of the methodology can also be used separately to tackle specific challenges, giving more flexibility to its application. Three distinct case studies are presented to demonstrate the effectiveness and transversality of the solution. Real-time geolocation data streams of buses from two distinct public transport networks are used to demonstrate the detection of vehicle-based operations and compare the distinct approaches proposed by this work. The buses operations produce a structured sequence of events that describes the behaviour of the buses. This behaviour is mapped through the application of process mining techniques uncovering analysis opportunities and discovering bottlenecks in the process. Geolocation data from an international logistics company is exploited for monitoring logistics processes, namely for detecting vehicle-based operations in real time, showing the effectiveness of the proposed solution to solve specific industry problems. The results of this work reveal new possibilities for geolocation data and its potential to generate process knowledge. The exploitation of geolocation data in the public transport and logistics contexts poses as an opportunity for improving the monitoring and management of vehicle-based operations. This can lead to into improvements in the process efficiency and consequently higher profit and better service quality

Young, Healthy Subjects Can Reduce the Activity of Calf Muscles When Provided with EMG Biofeedback in Upright Stance

Recent evidence suggests the minimization of muscular effort rather than of the size of bodily sway may be the primary, nervous system goal when regulating the human, standing posture. Different programs have been proposed for balance training; none however has been focused on the activation of postural muscles during standing. In this study we investigated the possibility of minimizing the activation of the calf muscles during standing through biofeedback. By providing subjects with an audio signal that varied in amplitude and frequency with the amplitude of surface electromyograms (EMG) recorded from different regions of the gastrocnemius and soleus muscles, we expected them to be able to minimize the level of muscle activation during standing without increasing the excursion of the center of pressure (CoP). CoP data and surface EMG from gastrocnemii, soleus and tibialis anterior muscles were obtained from 10 healthy participants while standing at ease and while standing with EMG biofeedback. Four sensitivities were used to test subjects' responsiveness to the EMG biofeedback. Compared with standing at ease, the two most sensitive feedback conditions induced a decrease in plantar flexor activity (~15%; P < 0.05) and an increase in tibialis anterior EMG (~10%; P < 0.05). Furthermore, CoP mean position significantly shifted backward (~30 mm). In contrast, the use of less sensitive EMG biofeedback resulted in a significant decrease in EMG activity of ankle plantar flexors with a marginal increase in TA activity compared with standing at ease. These changes were not accompanied by greater CoP displacements or significant changes in mean CoP position. Key results revealed subjects were able to keep standing stability while reducing the activity of gastrocnemius and soleus without loading their tibialis anterior muscle when standing with EMG biofeedback. These results may therefore posit the basis for the development of training protocols aimed at assisting subjects in more efficiently controlling leg muscle activity during standing

Multiobjective metaheuristic approaches for mean-risk combinatorial optimisation with applications to capacity expansion

Tese de doutoramento. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 200

Recommending Influencers to Merchants using Matching Game Algorithm

The goal of this work was to apply the ``Gale-Shapley'' algorithm to a real-world problem. We analyzed the pairing of influencers with merchants, and after a detailed specification of the variables involved, we conducted experiments to observe the validity of the approach. We conducted an analysis of the problem of aligning the interests of merchants to have digital influencers promote their products and services. We propose applying the matching algorithm approach to address this issue. We demonstrate that it is possible to apply the algorithm and still achieve corporate objectives by translating performance indicators into the desired ranking of influencers and product campaigns to be advertised by merchants