Mobile learning: benefits of augmented reality in geometry teaching

As a consequence of the technological advances and the widespread use of mobile devices to access information and communication in the last decades, mobile learning has become a spontaneous learning model, providing a more flexible and collaborative technology-based learning. Thus, mobile technologies can create new opportunities for enhancing the pupils’ learning experiences. This paper presents the development of a game to assist teaching and learning, aiming to help students acquire knowledge in the field of geometry. The game was intended to develop the following competences in primary school learners (8-10 years): a better visualization of geometric objects on a plane and in space; understanding of the properties of geometric solids; and familiarization with the vocabulary of geometry. Findings show that by using the game, students have improved around 35% the hits of correct responses to the classification and differentiation between edge, vertex and face in 3D solids.This research was supported by the Arts and Humanities Research Council Design Star CDT (AH/L503770/1), the Portuguese Foundation for Science and Technology (FCT) projects LARSyS (UID/EEA/50009/2013) and CIAC-Research Centre for Arts and Communication.info:eu-repo/semantics/publishedVersio

Assessing patterns of geographic dispersal of Gelidium sesquipedale (Rhodophyta) through RAPD differentiation of populations

Randomly amplified polymorphic DNAs (RAPDs) of bulked genomic DNA samples were used to analyse the genetic differentiation of Gelidium sesquipedale populations. They reflect the pat terns of gene flow, which in turn depend on the dispersal mechanisms of the species and on near-shore ocean currents. Fourteen populations were sampled from northern France to Morocco, covering the geographical distribution of the species. A single bulk DNA sample (from 15 individuals) was used in each population, under the assumption that the resulting patterns represent the populations' most common genetic features. To test this, we investigated the genetic variability among 5 bulk samples within a single population. Genetic distances among bulks were very low (average = 0.065) and were signifi- cantly lower than those observed between geographically separated populations (average = 0.241). Neighbour-joining analysis of the distance matrix of populations separated a well-supported group including populations of northern Spain and of northern France, and a less-supported group containing populations of northern Portugal. Multidimensional scaling of the genetic distance matrix revealed 2 isolated populations, Sao Rafael in southern Portugal and Algeciras in southern Spain. These patterns of genetic differentiation are discussed under the available data on the near-shore ocean currents. Results suggest that the genetic differentiation of G. sesquipedale populations may be used as a biological tracer of prevailing flows and barriers of the near-shore currents. A positive correlation between geographical and genetic distances of G. sesquipedale populations along the species geographical dis tribution was found, suggesting that a continuous transport of detached fronds and their reattachment to new substrate must be an effective dispersal mechanism of the species, sustaining the gene flow among populations

Ovarian Borderline Tumor and Fertility-Sparing Surgery

Ovarian borderline tumors (OBTs) are frequently diagnosed in women of reproductive age. There is no consensus about their management, and it sometimes represents a dilemma aboutwhat should be done: fertility sparing surgery or a hysterectomy with salpingo-oophorectomy? Case: A 32-year-old nulligravida, diagnosed with a right ovarian borderline tumor is presented. She underwent pelvic washings, right salpingo-oophorectomy, appendectomy, and omental and peritoneal biopsies (laparotomic approach). Macroscopically, the left ovary was normal and subsequent exploration for staging was also normal, including the lymph nodes. Intraoperatively, frozen section examination was unclear, suggesting an OBT. Results: The final histopathologic diagnosis was ovarian borderline tumor, stage IIC (International Federation of Gynecology and Obstetrics [FIGO] staging). The patient expressed a desire to preserve her fertility. Thirty-six months postsurgery, she became pregnant spontaneously and delivered a healthy newborn at term. Conclusions: Conservative surgery can be performed in young patients treated for an OBT, provided they are closely followed up and that this surgery is performed after careful consideration and informed consent. It is, however, controversial with respect to performing hysterectomy and salpingo-oopherectomy upon the patient’s completion of childbearing

Artificial reefs: from ecological processes to fishing enhancement tools

info:eu-repo/semantics/publishedVersio

Towards self-organized service-oriented multi-agent systems

The demand for large-scale systems running in complex and even chaotic environments requires the consideration of new paradigms and technologies that provide flexibility, robustness, agility and responsiveness. Multiagents systems is pointed out as a suitable approach to address this challenge by offering an alternative way to design control systems, based on the decentralization of control functions over distributed autonomous and cooperative entities. However, in spite of their enormous potential, they usually lack some aspects related to interoperability, optimization in decentralized structures and truly self-adaptation. This paper discusses a new perspective to engineer adaptive complex systems considering a 3-layer framework integrating several complementary paradigms and technologies. In a first step, it suggests the integration of multi-agent systems with service-oriented architectures to overcome the limitations of interoperability and smooth migration, followed by the use of technology enablers, such as cloud computing and wireless sensor networks, to provide a ubiquitous and reconfigurable environment. Finally, the resulted service-oriented multi-agent system should be enhanced with biologically inspired techniques, namely self-organization, to reach a truly robust, agile and adaptive system

Hypophosphatemia As a Possible Biomarker for Epileptic Seizures at the Emergency Department

Introduction: Hypophosphatemia seems to be temporally associated with seizures, despite not being considered a trigger. We aimed to evaluate hypophosphatemia as a biomarker for seizures. Methods: Retrospective study, including all consecutive patients admitted at our central hospital's emergency department from 01/01-31/03/2021, screened as "altered consciousness/syncope" or "seizures", with available phosphate levels. Results: 277 patients included, mostly male (61.7%), mean age 64.3 years. Final diagnosis was "seizure" in 34.7% and "other diagnosis" in 65.3%. Patients with seizures were younger (p200U/L) was more frequent in the seizure group (p=0.04). Odds ratio (OR) of hypophosphatemia for seizures was 4.330 (CI 95% 2.170-8.640, p<0.001), persisting after correction for confounders. OR of hyperCK was 1.890 (CI 95% 1.060-3.371, p=0.03), losing significance when adjusted. Sensitivity was low for both. Hypophosphatemia was more specific (91.2% vs 79.9%). Conclusions: Our findings support hypophosphatemia as a seizure biomarker. More studies are needed.info:eu-repo/semantics/publishedVersio

Development of vascular grafts of bacterial cellulose

Dissertação de doutoramento em Engenharia BiomédicaBypass surgery is a vascular surgeon’s fundamental tool in the treatment of some arterial and venous diseases, many of which are caused by atherosclerosis. The procedure uses a vascular graft to replace, bypass or maintain function of damaged, occluded or diseased blood vessels. The most common approach is to use a native vessel, such as the saphenous vein, from the patient as the bypass conduit. Alternatively, when an autologous vessel is not available due to progression of the disease or prior surgeries, synthetic alternatives are used. However, the current synthetic alternatives have been plagued with little success in small caliber vessels (<6mm). Bacterial cellulose (BC) has been presented as an alternative material for the production of a vascular graft. It presents good mechanical characteristics allied with non-thrombogenicity, hemo- and biocompatibility. Several methods have been suggested in the literature that allow the production of tubular BC grafts. The work developed and presented in this thesis had two aims: further development and performance enhancement of a current production method and also, the development of a new and effective method for graft production. A current, and common, method of graft production takes advantage of the way in which the Gluconacetobacter bacteria produces BC at air-culture medium interfaces. By providing an oxygen permeable tubular scaffold it is possible to produce tubular BC constructs. However, the tubular BC constructs produced in this method were found to be lacking in mechanical strength. Towards enhancing their performance a nanocomposite of BC and poly(vinyl alcohol) (PVA) was developed. Blood contacting materials have necessarily to be able to perform well in regards to their hemocompatibility and thrombogenicity and, as such, the BC/PVA nanocomposite was so tested, as well as BC. The standard characterization of the whole blood clotting time, plasma recalcification and hemolysis index were all determined. In addition, as a more in depth analysis, complement system and Factor XII activation along with a detailed characterization of platelet adhesion and activation was also assessed. Results suggested that both BC and BC/PVA induced low levels of Factor XII and platelet activation and this is possibly the main cause for the good hemocompatibility presented by of both materials. The presence of PVA in the nanocomposite did not hinder the hemocompatibility of BC, in some cases adding to the performance of the material. Along with the, aforementioned, necessary characterization of the BC/PVA nanocomposite, the mechanical and morphological characteristics of the material were also tested and shown to be significantly different in terms of fiber structure and organization upon drying. The performance of the nanocomposite regarding mechanical characteristics was expected to outperform those of BC. However, the tensile tests performed suggested otherwise. A more detailed morphological analysis of BC/PVA showed that, once dried, the fiber structure changed dramatically; presenting two very distinct, dense and porous, regions. These structural characteristics were found to be associated with a heterogeneous distribution of PVA throughout the nanocomposite which affected the mechanical performance and permeability of the dried nanocomposite. Finally, through the course of several developmental stages of the graft, an alternative method of production that allied both technical facility and low cost was discovered. This method was able of outperforming the previous iteration of the BC grafts and was, later, shown to be a viable and cost effective method of graft production. The grafts produced by this novel method allowed for mechanically strong and yet compliant grafts to be produced, as was demonstrated by the mechanical characterization performed, in a reproducible way. Continued characterization showed a luminal topography similar to that of a native vessel, far exceeding ePTFE and Dacron in this regard. Additionally, an important mechanical characteristic; and frequent cause of graft failure, compliance was also determined and shown to be comparable on the luminal surface when compared to native arteries and again outperforming the current industry standards. The grafts were later shown to perform well in vivo in pigs. Surgical implantation was performed in a femoro-femoral arterial bypass bridge to study the in vivo viability of the graft. Results demonstrated patency after 1 month of implantation with the presence of an endothelial cell population on the luminal surface of the graft.Cirurgia de bypass é uma ferramenta fundamental no tratamento de algumas doenças arteriais e venosas, muitas destas doenças causadas por aterosclerose. Este procedimento utiliza uma prótese vascular para substituir, formar uma ponte ou manter o funcionamento de um vaso danificado, obstruído ou doente. O processo mais comum utiliza um vaso nativo, como a veia safena, como a prótese vascular. Quando um vaso autólogo não estiver disponível, devido à progressão natural da doença ou cirurgias anteriores, utilizam-se alternativas sintéticas. Contudo, as actuais alternativas sintéticas têm obtido pouco sucesso em vasos de pequeno calibre (<6mm). Celulose bacteriana (BC) apresenta-se como uma alternativa para a produção de próteses vasculares. Apresenta boas características mecânicas aliadas a não-trombogenicidade, hemo- e biocompatibilidade. Vários métodos de produção de vasos de celulose bacteriana têm sido propostos na literatura. O trabalho desenvolvido e apresentado nesta tese teve dois objectivos: continuar o desenvolvimento e melhorar o desempenho dos actuais métodos de produção, bem como, o desenvolvimento de uma nova e eficaz maneira de produzir próteses. O actual e mais comum, método de produção aproveita a forma como as bactérias do género Gluconacetobacter produzem BC nos interfaces ar-meio de cultura. Utilizando um suporte tubular permeável a oxigénio é possível produzir estruturas tubulares de celulose. Contudo, as estruturas tubulares produzidas por estes métodos demonstraram fracas propriedades mecânicas. Com o objectivo de melhorar o desempenho mecânico desenvolveu-se um nanocompósito de BC e poli(vinil álcool) (PVA). Materiais que contactam com sangue têm que ser capazes de ter um bom desempenho em termos de hemocompatibilidade e trombogenicidade e como tal, o nanocompósito de BC/PVA, bem como a BC, foram testadas. Foi feita a caracterização do tempo de coagulação de sangue total, recalcificação do plasma e índice de hemólise. Para além destes, foi analisada a activação do sistema de complemento e Factor XII bem como uma caracterização detalhada da adesão e activação de plaquetas. Os resultados sugerem que a BC e o BC/PVA, induzem baixos níveis de activação do Factor XII e plaquetas, o que poderá ser a principal razão pela boa hemocompatibilidade apresentada pelos materiais. A presença de PVA no nanocompósito não afecta a hemocompatibilidade da BC, em alguns casos até melhorando o seu desempenho. Para além desta caracterização do BC/PVA, o nanocompósito foi caracterizado a nível mecânico e morfológico e os resultados mostraram diferenças significativas em termos de estrutura e organização das fibras após secagem. Esperava-se que o desempenho do nanocompósito, em termos de características mecânicas, seria superior à BC, no entanto isto não se veio a verificar. Uma análise morfológica mais detalhada do BC/PVA mostrou que, após secagem, a estrutura das fibras sofre alterações profundas; apresentando duas regiões distintas, uma densa e outra porosa. Estas distintas regiões devem-se à distribuição heterogénea do PVA no nanocompósito, por seu turno, afecta o desempenho mecânico e permeabilidade do nanocompósito seco. Por fim, a longo do curso de várias fases de desenvolvimento das próteses, foi descoberto um método alternativo de produção que aliava facilidade técnica e baixo custo. Este método mostrou ser capaz de produzir próteses melhores que todas as versões anteriores e, mais tarde, mostrou ser um método de produção viável e de baixo-custo. As próteses produzidas por este método novo permitem obter forças mecânicas superiores sem perder a complacência do material, como foi demonstrado pela caracterização mecânica, de forma reprodutível. A continuada caracterização das próteses mostrou uma topografia luminal semelhante ao dos vasos nativos, superando o ePTFE e o Dacron. Adicionalmente, uma importante característica mecânica, e frequente causa de falha das próteses, a complacência foi também determinada e mostrou ser comparável à complacência da superfície luminal de artérias nativas, tendo portanto um melhor desempenho que as próteses industriais actuais. As próteses mostraram, mais tarde, ter também um bom desempenho in vivo em porcos. As próteses foram implantadas numa ponte femoral de forma a estudar a viabilidade in vivo. Os resultados obtidos demonstraram patência ao fim de 1 mês de implantação com a presença de células endoteliais na superfície luminal da prótese

Thermal and acoustic performance of interlocking compressed earth blocks masonry

The earth construction is an ancient building technique that, with the emergence of new materials and technologies, has received less attention during the last decades. Nevertheless, the new concerns in terms of environmental protection and sustainable construction have recently led to its revalorization. The masonry construction with interlocking compressed earth blocks (ICEB) is one of the earth construction techniques that features several advantages and has received the most developments in the last years. This type of masonry is currently being used worldwide, especially in developing countries, although the suspicions about its performance remain very wide. Another problem is the lack of standards and documents that can support designers in projects development. This research aims to contribute in this direction, creating bases to help designers in their work and contribute to the knowledge about this type of construction. Furthermore, there has been an increase in the standard requirements related to the comfort inside the building, namely at the thermal and acoustic level. So, the knowledge of the thermal and acoustic performance of the ICEB masonry is essential to define and optimize the constructive solutions at the design stage. Experimental studies were carried out in order to characterize these properties. The results are presented and discussed. It is expected that the results obtained serve as design support for this type of construction.FEDER funds through the Competitivity Factors Operational Programme - COMPETEFCT – Foundation for Science and Technology- project POCI-01-0145-FEDER-00763

A systematic procedure to enhance reproducibility of SWASV cycles in the determination of toxic metals in real samples

This work presents for the first time a systematic study on the optimization of the electrochemical cleaning time of a mercury film when it is used as a working electrode material in the analysis of toxic metals, such as Pb2+, used as model metal, in real samples by SWASV. The optimization study for the film’s cleaning time aimed at attaining a Pb2+ minimum value in the film after the re-oxidation step of the pre-concentrated metal, given the impossibility of complete removal of traces of the electroactive species from the film. This value was kept constant in each concentration range studied ensuring thus that all assays were performed in initial identical conditions. An assay performed on a synthetic sample was taken as reference. In it, given the absence of matrix effects, and after the electrochemical cleaning step, a direct proportionality was observed between the residual amounts of Pb2+ in the film (which for the cleaning time used was never completely removed) and Pb2+ concentration in the solution. This fact determined a high correlation between Pb2+ peak current and Pb2+ concentration which was not observed when real samples (tree leaves) were analyzed. This behavior may result from the presence of the interfering surfactants always present in real samples of complex matrix. Cleaning time optimization was performed for the following Pb2+ concentration ranges in the real samples of complex matrix: 0.006-0.020, 0.020-0.080, 0.060-0.200 and 0.100-0.600 ppb. As expected, in order to obtain identical levels of film’s cleaning efficiency, the need for longer cleaning times has been observed for higher concentrations. The optimized cleaning times for the concentration ranges under study were 120, 150, 180 e 300 s, respectively