Radio link quality estimation in wireless sensor networks: a survey

Radio link quality estimation in Wireless Sensor Networks (WSNs) has a fundamental impact on the network performance and also affects the design of higher-layer protocols. Therefore, for about a decade, it has been attracting a vast array of research works. Reported works on link quality estimation are typically based on different assumptions, consider different scenarios, and provide radically different (and sometimes contradictory) results. This article provides a comprehensive survey on related literature, covering the characteristics of low-power links, the fundamental concepts of link quality estimation in WSNs, a taxonomy of existing link quality estimators, and their performance analysis. To the best of our knowledge, this is the first survey tackling in detail link quality estimation in WSNs. We believe our efforts will serve as a reference to orient researchers and system designers in this area.

Dinossáurios Eocretácicos de Lagosteiros

According to an ancient folkloric legend, Our Lady, stepping down from the sea, would have rided on a mule to the platform above the cliffs named Pedra da Mua at Lagosteiros'bay, near Espichel cape. Mule's footprints, regarded by fishermen as evidence, would be clearly recognizable on exposed surfaces of the rocks. Indeed there are footprints but from Dinosaurs of latest Jurassic, Portlandian age, this spectacular locality being specially rich in giant Sauropod tracks (that have seldom been found elsewhere in Europe). As we proceeded to its study, another locality with Dinosaur footprints, Lower Cretaceous (Hauterivian) in age, was found on the northern cliffs at Lagosteiros. It is probably the richest one in european Lower Cretaceous and the only of this age known in Portugal, so we decided to give priority to its study. Dinosaur tracks have been printed on calciclastic sands in a lagoonal environment protected by fringing coral reefs. There have been emersion episodes; beaches were frequented by Dinosaurs. Later on, the marine barremian ingression restablished a gulf and such animals could not come here any more. Under a paleogeographical viewpoint, the evidence of a marine regression near the end of Hauterivian is to be remarked. Five types of tracks and footprints have been recognized: - Neosauropus lagosteirensis, new morphogenus and species, tracks from a giant Sauropod, perhaps from Camarasaurus; with its proportions the total length of the author would be about 15,5 m. These are the only Sauropod tracks known till now in Europe's Lower Cretaceous. - tracks from a not so big quadruped, maybe a Sauropod (young individual?); however it is not impossible that they were produced by Stegosaurians or Ankylosaurians. -Megalosauropus (?Eutynichnium) gomesi new morphospecies, four Theropod tracks most probably produced by megalosaurs. - Iguanodon sp., represented by some footprints and specially by a set corresponding to the feet and tail from an individual standing in a rest position. - problematical, quite small-sized biped (maybe an Ornithopod related to Camptosaurus). Evidence points to a richer fauna than that known in barremian "Dinosaur sandstones" from a nearby locality, Boca do Chapim. Lagosteiros' association clearly indicates the predominance of herbivores, which required large amounts of vegetable food in the neighbourhood. This is an indirect evidence of the vegetal wealth, also suggested by associations of plant macrofossils, polen and spores found in early Cretaceous sediments at the same region. The relatively high proportion of Theropoda is related to the wealth of the whole fauna, which comprised a lot of the prey needed by such powerful flesh-eaters. The evidence, as a whole, points out to a warm and moist climate. All the tracks whose direction could be measured are directed to the southern quadrants, this being confirmed by the approximative direction of other footprints. Massive displacements (migration?) could take place during a brief emersion episode. This may result from the ingression of barremian seas, flooding the region and restablishing here a small gulf. Even if the arrival of the waters damaged certain footprints it has not destroyed them completely, thus allowing the preservation of such evidence from a remote past.

Disparities in cervical and breast cancer mortality in Brazil

OBJECTIVE To analyze cervical and breast cancer mortality in Brazil according to socioeconomic and welfare indicators. METHODS Data on breast and cervical cancer mortality covering a 30-year period (1980-2010) were analyzed. The data were obtained from the National Mortality Database, population data from the Brazilian Institute of Geography and Statistics database, and socioeconomic and welfare information from the Institute of Applied Economic Research. Moving averages were calculated, disaggregated by capital city and municipality. The annual percent change in mortality rates was estimated by segmented linear regression using the joinpoint method. Pearson’s correlation coefficients were conducted between average mortality rate at the end of the three-year period and selected indicators in the state capital and each Brazilian state. RESULTS There was a decline in cervical cancer mortality rates throughout the period studied, except in municipalities outside of the capitals in the North and Northeast. There was a decrease in breast cancer mortality in the capitals from the end of the 1990s onwards. Favorable socioeconomic indicators were inversely correlated with cervical cancer mortality. A strong direct correlation was found with favorable indicators and an inverse correlation with fertility rate and breast cancer mortality in inner cities. CONCLUSIONS There is an ongoing dynamic process of increased risk of cervical and breast cancer and attenuation of mortality because of increased, albeit unequal, access to and provision of screening, diagnosis and treatment. 

Job quality in Europe: the North-South divide

This paper examines the job quality in Europe. It is based on the results of the Fourth European Foundation Survey on working conditions covering different dimensions including work organisation, job content, autonomy at work, aspects of worker dignity, working time and work-life balance, working conditions and safety in the workplace. The results point to the existence of great diversity in the job quality across Europe and the north-south divide. The job quality differences are related to the variety of social and institutional contexts. The countries of Southern Europe, with their social and institutional contexts falling within the scope of the Mediterranean model, generally present indicators below the European average contrasting Nordic countries having the best job quality indicators.

Numerical evaluation of three-dimensional scarf repairs in carbon-epoxy structures

The widespread employment of carbon-epoxy laminates in high responsibility and severely loaded applications introduces an issue regarding their handling after damage. Repair of these structures should be evaluated, instead of their disposal, for cost saving and ecological purposes. Under this perspective, the availability of efficient repair methods is essential to restore the strength of the structure. The development and validation of accurate predictive tools for the repairs behaviour are also extremely important, allowing the reduction of costs and time associated to extensive test programmes. Comparing with strap repairs, scarf repairs have the advantages of a higher efficiency and the absence of aerodynamic disturbance. This work reports on a numerical study of the tensile behaviour of three-dimensional scarf repairs in carbon-epoxy structures, using a ductile adhesive (Araldite® 2015). The finite elements analysis was performed in ABAQUS® and Cohesive Zone Modelling was used for the simulation of damage onset and growth in the adhesive layer. Trapezoidal cohesive laws in each pure mode were used to account for the ductility of the specific adhesive mentioned. A parametric study was performed on the repair width and scarf angle. The use of over-laminating plies covering the repaired region at the outer or both repair surfaces was also tested as an attempt to increase the repairs efficiency. The obtained results allowed the proposal of design principles for repairing composite structures.

Association between social capital and self-perception of health in Brazilian adults

OBJECTIVE To investigate the association between social capital and social capital and self-perception of health based on examining the influence of health-related behaviors as possible mediators of this relationship.METHODS A cross-sectional study was used with 1,081 subjects, which is representative of the population of individuals aged 40 years or more in a medium-sized city in Southern Brazil. The subjects who perceived their health as fine, bad or very bad were considered to have a negative self-perception of their health. The social capital indicators were: number of friends, people from whom they could borrow money from when needed; the extent of trust in community members; whether or not members of the community helped each other; community safety; and extent of participation in community activities. The behaviors were: physical activity during leisure time, fruits and vegetable consumption, tobacco use and alcohol abuse. The odds ratios (OR) and confidence intervals (CI) 95% were calculated by binary logistic regression. The significance of mediation was verified using the Sobel test.RESULTS Following adjustment for demographic and clinical variables, subjects with fewer friends (OR = 1.39, 95%CI 1.08;1.80), those who perceived less frequently help from people in the neighborhood (OR = 1.30, 95%CI 1.01;1.68), who saw the violent neighborhood (OR = 1.33, 95%CI 1.01;1.74) and who had not participated in any community activity (OR = 1.39, 95%CI 1.07;1.80) had more negative self-perception of their health. Physical activity during leisure time was a significant mediator in the relationship between all social capital indicators (except for the borrowed money variable) and self-perceived health. Fruit and vegetable consumption was a significant mediator of the relationship between the extent of participation in community activities and self-perceived health. Tobacco use and alcohol abuse did not seem to have a mediating role in any relationship.CONCLUSIONS Lifestyle seems to only partially explain the relationship between social capital and self-perceived health. Among the investigated behaviors, physical activity during leisure time is what seems to have the most important role as a mediator of this relationship.

Evaluating the use of in-store measures in retail food stores and restaurants in Brazil

ABSTRACTOBJECTIVE To assess inter-rater reliability, test-retest reliability, and construct validity of retail food store, open-air food market, and restaurant observation tools adapted to the Brazilian urban context.METHODS This study is part of a cross-sectional observation survey conducted in 13 districts across the city of Sao Paulo, Brazil in 2010-2011. Food store and restaurant observational tools were developed based on previously available tools, and then tested it. They included measures on the availability, variety, quality, pricing, and promotion of fruits and vegetables and ultra-processed foods. We used Kappa statistics and intra-class correlation coefficients to assess inter-rater and test-retest reliabilities in samples of 142 restaurants, 97 retail food stores (including open-air food markets), and of 62 restaurants and 45 retail food stores (including open-air food markets), respectively. Construct validity as the tool’s abilities to discriminate based on store types and different income contexts were assessed in the entire sample: 305 retail food stores, 8 fruits and vegetable markets, and 472 restaurants.RESULTS Inter-rater and test-retest reliability were generally high, with most Kappa values greater than 0.70 (range 0.49-1.00). Both tools discriminated between store types and neighborhoods with different median income. Fruits and vegetables were more likely to be found in middle to higher-income neighborhoods, while soda, fruit-flavored drink mixes, cookies, and chips were cheaper and more likely to be found in lower-income neighborhoods.CONCLUSIONS The measures were reliable and able to reveal significant differences across store types and different contexts. Although some items may require revision, results suggest that the tools may be used to reliably measure the food stores and restaurant food environment in urban settings of middle-income countries. Such studies can help .inform health promotion interventions and policies in these contexts.

Taper angle optimization of scarf repairs in carbon-epoxy laminates

The increasing use of Carbon-Fibre Reinforced Plastic (CFRP) laminates in high responsibility applications introduces an issue regarding their handling after damage. The availability of efficient repair methods is essential to restore the strength of the structure. The availability of accurate predictive tools for the repairs behaviour is also essential for the reduction of costs and time associated to extensive tests. This work reports on a numerical study of the tensile behaviour of three-dimensional (3D) adhesively-bonded scarf repairs in CFRP structures, using a ductile adhesive. The Finite Element (FE) analysis was performed in ABAQUS® and Cohesive Zone Models (CZM’s) was used for the simulation of damage in the adhesive layer. A parametric study was performed on two geometric parameters. The use of overlaminating plies covering the repaired region at the outer or both repair surfaces was also tested as an attempt to increase the repairs efficiency. The results allowed the proposal of design principles for repairing CFRP structures.

Consistent state software transactional memory

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do Grau de Mestre em Engenharia Informática

Produção de biodiesel mediante ecovalorização de óleos alimentares: otimização de estratégias de produção e de controlo de qualidade

Os biocombustíveis são combustíveis com origem em matérias-primas naturais e renováveis, como óleos vegetais, gorduras animais, óleos e gorduras residuais entre outros, utilizados como substitutos de combustíveis minerais, como o gasóleo ou gasolina. Esta alternativa aos combustíveis de origem fóssil, tem-se vindo a revelar cada vez mais atrativa, sobretudo devido aos seus benefícios ambientais, destacando-se entre ele s o facto de serem biodegradáveis, não tóxicos e emitirem menos gases aquando da sua combustão, não contribuindo deste modo para o aumento do efeito de estufa na atmosfera. Na execução do presente trabalho, assume-se como finalidade o desenvolvimento de procedimentos laboratoriais sistemático de modo, com o intuito de elaborar um controlo de qualidade para a produção do biodiesel que permita a implementação de novas medidas processuais melhorando a produção de biodiesel. Este trabalho é resultado do estágio no Ecoparque Braval Valorização e Tratamento de Resíduos Sólidos, S.A. Com a avaliação sistemática e contínua, tanto da matéria-prima usada na produção do biodiesel, como do produto final em si, através de procedimentos laboratoriais específicos para o efeito, visa-se que em distintas fases do processo de produção do biodiesel seja compreendido o que ocorre de forma efetiva, e assim se assumam medidas preventivas e corretivas com o intuito de melhorar a qualidade do produto final. Na elaboração deste trabalho foram também reunidos esforços no sentido de controlar as especificações do óleo à entrada das instalações e iniciar o controlo de qualidade do produto final através de análises comparativas elaboradas no laboratório da Unidade de Produção de Biodiesel do Ecoparque Brava! - Valorização e Tratamento de Resíduos Sólidos, S.A. Outra abordagem do trabalho em questão, incide no estudo do efeito da variação das condições operatórias, nomeadamente a razão molar metanol/óleo , quantidade de catalizador na produção de biodiesel, nomeadamente, na quantidade de glicerina obtida como subproduto da reação e na facilidade de separação de fases. Neste sentido, o trabalho proposto pretende controlar a qualidade da matéria-prima usada, a qualidade do produto final e apresentar os aspetos-chave que deve m ser considerados para urna melhor gestão do s recursos de produção do biocombustível.

Mechanical properties of stent-graft materials

An aneurysm is a localized blood-filled dilatation of an artery whose consequences can be deadly. One of its current treatments is endovascular aneurysm repair, a minimally invasive procedure in which an endoprosthesis, called a stent-graft, is placed transluminally to prevent wall rupture. Early stent-grafts were custom designed for the patient through the assembling of off-the-shelf components by the operating surgeon. However, nowadays, stent-grafts have become a commercial product. The existing endoprostheses differ in several aspects, such as shape design and materials, but they have in common a metallic scaffold with a polymeric covering membrane. This article aims to gather relevant information for those who wish to understand the principles of stent-grafts and even to develop new devices. Hence, a stent-graft classification based on different characteristics is presented and the desired features for an ideal device are pointed out. Additionally, the materials currently in use to fabricate this type of endoprosthesis are reviewed and new materials are suggested.

Student performance analysis under different moodle course designs

This work extends a recent comparative study covering four different courses lectured at the Polytechnic of Porto - School of Engineering, in respect to the usage of a particular Learning Management System, i.e. Moodle, and its impact on students' results. A fifth course, which includes a number of resources especially supporting laboratory classes, is now added to the analysis. This particular course includes a number of remote experiments, made available through VISIR (Virtual Instrument Systems in Reality) and directly accessible through links included in the Moodle course page. We have analyzed the students' behavior in following these links and in effectively running experiments in VISIR (and also using other lab related resources, in Moodle). This data have been correlated with students' classifications in the lab component and in the exam, each one weighting 50% of their final marks. We aimed to compare students' performance in a richly Moodle-supported environment (with lab component) and in a poorly Moodle-supported environment (with only theoretical component). This question followed from conclusions drawn in the above referred comparative study, where it was shown that even though a positive correlation factor existed between the number of Moodle accesses and the final exam grade obtained by each student, its explanation behind was not straightforward, as the quality of the resources was preponderant over its quantity.

Structuring and moodleing a course: case studies at the polytechnic of Porto - School of engineering

This work presents a comparative study covering four different courses lectured at the Polytechnic of Porto - School of Engineering, in respect to the usage of a particular Learning Management System, i.e. Moodle, and its impact on students' results. Even though positive correlation factors exist, e.g. between the number of Moodle accesses versus the final exam grade obtained by each student, the explanation behind it may not be straightforward. Mapping this particular factor to course numbers reveals that the quality of the resources might be preponderant and not only their quantity. This paper also addresses teachers who used this platform as a complement to their courses (b-learning) and identifies some particular issues they should be aware in order to potentiate students' engagement and learning.

Engaging students by moodleing a course? Case studies at the Polytechnic of Porto–School of Engineering

This work presents a comparative study covering four different courses lectured at the Polytechnic of Porto - School of Engineering, regarding the usage of a particular Learning Management System, i.e. Moodle, and its impact on students' results. This study addresses teachers who used this platform as a complement to their courses (b-learning) and identifies some particular issues in order to potentiate students' engagement and learning. Even though positive correlation factors exist, e.g. between the number of Moodle accesses versus the final exam grade obtained by each student, the explanation behind it may not be straightforward. Mapping this particular factor to course numbers reveals that the quality of the resources might be preponderant and not only their quantity. These results point to the fact that some dynamic resources might enlarge students' engagement.

Constrains on the structure of Maio Island (Cape Verde) by a three-dimensional gravity model: Imaging partially exhumed magma chambers

We propose a 3-D gravity model for the volcanic structure of the island of Maio (Cape Verde archipelago) with the objective of solving some open questions concerning the geometry and depth of the intrusive Central Igneous Complex. A gravity survey was made covering almost the entire surface of the island. The gravity data was inverted through a non-linear 3-D approach which provided a model constructed in a random growth process. The residual Bouguer gravity field shows a single positive anomaly presenting an elliptic shape with a NWSE trending long axis. This Bouguer gravity anomaly is slightly off-centred with the island but its outline is concordant with the surface exposure of the Central Igneous Complex. The gravimetric modelling shows a high-density volume whose centre of mass is about 4500 m deep. With increasing depth, and despite the restricted gravimetric resolution, the horizontal sections of the model suggest the presence of two distinct bodies, whose relative position accounts for the elongated shape of the high positive Bouguer gravity anomaly. These bodies are interpreted as magma chambers whose coeval volcanic counterparts are no longer preserved. The orientation defined by the two bodies is similar to that of other structures known in the southern group of the Cape Verde islands, thus suggesting a possible structural control constraining the location of the plutonic intrusions.