Detection and Tracking of Coronal Holes in Solar Images

The study of solar activity and its effects on space weather is of great interest to humankind. Whether to study the dynamic of the star itself or the resulting phenomena and associated con-sequences from it, every different feature of the Sun provides valuable data to perform these studies. Features of the Sun are, for the most part, studied individually. However, studying differ-ent events collectively may result in new conclusions and findings that can be of as much interest as the individual studies. The objectives for this dissertation is to complement a Coronal Bright Points (CBPs) tracking algorithm, previously developed by (Pires, 2018), with an additional feature: detection of Coronal Holes (CHs) and classification of CBPs regarding whether they are located inside or outside of CHs. The proposed methodology is fully performed in Python language. Different image pro-cessing operations are applied in order to obtain a good detection result. The pre-processing stage involves an automatic image intensity normalization. The CHs detection uses a simple blur-ring before a fixed-value threshold segmentation. A last post-processing step includes performing adjustments to the detection results, using a closing morphologic operator, filling holes and an object detection. The data gathered by both tools is at the end consolidated, so that a result on the classifi-cation of each CBP is obtained and lastly added to the database

Effects of glycation by methylglyoxal in saccharomyces cerevisae

Mestrado em Bioquímica (Bioquímica Médica) Universidade de Lisboa; Faculdade de Ciências, 2021Glycation is the nonenzymatic modification of biomolecules caused by reactive dicarbonyl species. In vivo, the major physiological glycation agent is methylglyoxal. This compound’s formation occurs in all living cells, mainly nonenzymatically from dihydroxyacetone phosphate and D-glyceraldehyde 3-phosphate during glycolysis. When glycation occurs on proteins it originates advanced glycation end-products (AGEs), which will change the structure and stability of proteins, consequently impairing their functionality. AGEs tend to accumulate on cells, being associated with ageing and several human diseases, such as diabetes and amyloidotic neuropathies (Alzheimer’s disease, Parkinson’s disease and transthyretin amyloidosis). Hence, there is a growing interest in this post-translational modification. However, little is known about the physiologic effects of glycation, since most studies use in vitro approaches, which do not fully reproduce the in vivo process. Saccharomyces cerevisiae is an ideal model of in vivo glycation, being able to reproduce the effects that happen in higher eukaryotic cells. The in vivo study and use of Saccharomyces cerevisiae cells with different genetic backgrounds, gives us an accurate vision of a wide range of phenotypical and physiological effects caused by glycation. In the present study we show that the glyoxalase system seems to be the major detoxifying mechanism of methylglyoxal, since mutations on this pathway lead to lower growth rates. Moreover, using fluorescence microscopy and flow cytometry we found that glycation is not sufficient to alter cell morphology or its viability. However, the effects of glycation seem to be devastating on mitochondrial activity causing its dysfunction and the accumulation of reactive oxygen species (ROS). These findings provide insight to uncover knowledge of the process of glycation, necessary for better comprehension and advance in the cure and early identification of many human diseases that haunt our society

Non-volant mammals (Mammalia) from Estação Ecológica Serra Geral do Tocantins

A comunidade de mamíferos terrestres foi amostrada em três localidades (1-Mateiros, TO; 2- Rio da Conceição, TO e 3- Formosa do Rio Preto, BA) no interior da Estação Ecológica Serra Geral do Tocantins. Para o registro dos marsupiais e pequenos roedores foram utilizadas armadilhas convencionais (5.396 armadilhas.noite) e armadilhas de queda (5.300 pitfalls.noite) nas diferentes fitofisionomias encontradas, entre elas: campo úmido, campo limpo, campo sujo, campo cerrado, cerrado sensu stricto, cerrado com afloramentos rochosos, mata de galeria e mata de galeria úmida. No caso dos mamíferos de médio e grande porte, foram obtidos registros casuais através de observação direta e evidências indiretas (rastros, fezes, crânios e carcaças de animais encontrados mortos). Foram amostradas 24 espécies de pequenos mamíferos e 17 espécies de mamíferos de médio e grande porte, totalizando 41 espécies para a região. Considerando-se os pequenos mamíferos, a comunidade foi representada por várias espécies raras e de abundância intermediária, e poucas espécies muito abundantes. Os roedores cricetídeos dominaram tanto em número de espécies (14) quanto em abundância (50% da comunidade). As espécies se distribuíram, basicamente, em dois tipos de fisionomias: um grupo esteve restrito aos ambientes florestais, e outro às formações abertas, demonstrando a grande seletividade de hábitats e a importância de se amostrar o mosaico de hábitats presente na região para uma melhor caracterização da diversidade deste grupo de mamíferos. Em termos biogeográficos, a fauna de pequenos mamíferos amostrada apresentou certa sobreposição com a fauna da Caatinga e da Amazônia, evidenciando a importância destes domínios para a composição de espécies das comunidades que habitam a porção norte do Cerrado, além da presença de espécies endêmicas e de distribuição geográfica restrita ao norte do domínio, caracterizando uma comunidade distinta de outras regiões do Cerrado. Em relação aos mamíferos de médio e grande porte, a presença de um elevado número de espécies ameaçadas de extinção (10) também ressalta a importância da preservação desta região.The terrestrial mammal community was surveyed along three distinct localities (1-Mateiros, TO; 2- Rio da Conceição, TO e 3- Formosa do Rio Preto, BA) in the Estação Ecológica Serra Geral do Tocantins. The small non-volant mammals were recorded by the use of conventional live traps (5,396 trap.nights) and pitfall traps (5,300 trap.nights) in the different physiognomies found, such as: "campo úmido", "campo limpo", "campo sujo", "campo cerrado", "cerrado sensu stricto", "cerrado sensu stricto with rocks", gallery forest and wet gallery forest. The large mammals were casually registered by visual or indirect evidences (tracks, feces, carcasses). We recorded 24 small non-volant mammals and 17 large mammals, totalizing 41 species for this region. The small mammal community was characterized by several rare and intermediate in abundance species, and few species very abundant. Rodents from the family Cricetidae dominated both in number of species (14) as in number of individuals (50% of the community). The species segregated among the forested and open formations, showing the great habitat selectivity and the importance to survey the habitat mosaic to characterize the diversity of this mammal group. The small non-volant mammal fauna surveyed showed some overlap with the fauna from the Caatinga and Amazon biomes, demonstrating the importance of these biomes in the faunal composition of the communities localized in the northern portion of the Cerrado. In addition, we also recorded endemic species and species with a restricted distribution to this north portion, characterizing a distinct community within the Cerrado. The large mammal community was characterized by a high number of threatened species (10), increasing the importance of this region in preserving the fauna of the northern portion of the Cerrado.BIOTA FAPESPFAPESPFundação O Boticário de Proteção à NaturezaPequi - Pesquisa e Conservação do CerradoConservação Internacional do Brasi

Clarifying what is a safe haven : an application to the Gold Market

In this thesis, a new approach to the notion of safe haven is developed, building on earlier innovative work by Paulos (2015), and departing from the widely used Baur and Lucey (2010) benchmark. It is our view that such a benchmark neglects the flight-to-quality property a safe haven asset should have. As such, we suggest implications for risk preferences in safe haven assets namely in their possible flight to quality property, we develop a method to test such preferences, and we conduct an extensive study, for a large class of assets, on whether or not gold could be perceived as a safe haven with respect to them. Gold was chosen for this application for the purposes of comparison with similar studies in the Baur and Lucey (2010) tradition. The role of volatility is extensively discussed, and explicitly incorporated in the definition of safe haven, shifting from the correlation between returns paradigm. Our analysis finds out that when the safe haven definition is extended in the ways we have suggested, gold is a safe haven against a wide variety of financial assets. This result differs from the existing literature, but makes perfect sense in our sample period (2008-2013), which comprises the financial crisis of 2007-08 and the European debt crisis. The debate between gold as a hedge and as a safe haven is also analysed. The prevailing dichotomy between such roles in the literature is broken, since our approach to safe haven uses volatility measures, whilst the previous paradigm was based on assets’ returns. As such, we find that there were subperiods where gold did perform the role of hedge, but we do not find a contradiction between that and the role of safe haven for the entire sample period.Nesta dissertação, é desenvolvida uma nova abordagem ao conceito de ativo de refúgio, com base na intuição inovadora presente em Paulos (2015), e abandonando a referência conceptual dominante na literatura, formalizada por Baur e Lucey (2010). Na nossa perspetiva, essa referência negligencia a propriedade da “preferência pela qualidade” própria dos ativos de refúgio. Deste modo, sugerimos implicações nas preferências dos agentes quanto ao risco que um ativo desta tipologia terá, desenvolvemos uma metodologia para testar essas preferências e conduzimos um amplo estudo, para uma larga classe de ativos, sobre se o ouro pode ou não, de acordo com a nova proposta conceptual, desempenhar a função de refúgio face a estes. O ouro é escolhido para possibilitar a comparação com os resultados de estudos que seguem a tradição de Baur e Lucey (2010). O papel da volatilidade é extensivamente analisado e incorporado de forma explícita na definição de ativo de refúgio, mudando o paradigma face à mera análise da correlação entre retornos. Neste estudo encontramos evidência que demonstra que o ouro é um refúgio face a todos os ativos testados, no âmbito da nossa proposta de conceito. Este resultado empírico difere da literatura existente, mas parece coerente com os eventos do período amostral (2008-2013), que compreende a crise financeira de 2007-08 e a crise das dívidas soberanas na Zona Euro. O debate entre as funções de ativo de refúgio versus elemento de cobertura de risco que o ouro pode desempenhar é também analisado. A dicotomia prevalecente entre as duas funções na literatura é abandonada, na medida em que a nossa definição de ativo de refúgio assenta em volatilidades, enquanto a abordagem dominante assentava na correlação entre taxas de retorno. Assim, na amostra temporal considerada encontramos subperíodos em que o ouro foi um elemento de cobertura de risco, mas este resultado não traduz qualquer contradição com o papel de ativo de refúgio que o ouro desempenha na totalidade o período amostral

Emergencies in a Territory of Mobility

UID/SOC/04647/2013The Mediterranean Sea is a historical stage of mobilities and has been a witness to important movements of people and goods since ancient times. In this liquid territory, different social processes of globalization can be observed; yet, in recent years, it has been predominantly depicted as an emergency scene, a crossing platform for those in search of refuge in Europe. This scenario becomes connected to a set of dimensions of securitization and quests for control that redirect the debates about national and European responsibilities regarding maritime territories. In this article, this issue is addressed exploring the construction and development of the social problem of refugees in the Mediterranean, departing from a frame analysis of news items thematically filtered from the digital platforms of two Italian newspapers in 2013-2015. The problem is contextualized in time and content progression, deepening the framing of some critical events, and reframing the Mediterranean as a referent/emergent territory of mobility.publishersversionpublishe

Employability in online higher education : a case study

This paper presents the results of a study on the perceptions of students and teachers from a distance education university on employability skills in higher education. The choice of skills that are important to the labour market has been the subject of controversy because it involves heterogeneous interests of different groups. Our case study departs from the following question: what are the perceptions of students and teachers about online higher education and the required skills for employability? To this end, a comparative study on the views of students and teachers was conducted, which emphasized the following dimensions: a) the most important skills for employability, and b) the skills to be developed for employability within undergraduate degrees in online learning. To collect the required data, a questionnaire was prepared and applied to students and teachers, taking as its main reference the theoretical model of Knight and Yorke (2006). In spite of the specificity of each group, the results reveal some similarities between students and teachers with regard to employability. The conclusions also highlight the need to promote research in this area in the European context

Continuous extraction strategies for monoclonal antibodies: From macro- to micro- scale

Aqueous two-phase extraction (ATPE) have shown to be a valuable option for the downstream processing of biopharmaceuticals, combining a high biocompatibility and selectivity with an easy and reliable scale up. Moreover, ATPE can overcome some of the technical drawbacks currently encountered using established purification platforms, such as batch operation, diffusional limitations and scale-related problems. We have developed a continuous ATPE process incorporating three different steps (extraction, back-extraction and washing) for the capture of monoclonal antibodies (mAbs). The ATPE process was set up and validated in a pump mixer-settler battery and successfully applied to a Chinese hamster ovary and a PER.C6® cell supernatant. The limited predictive design of ATPE, however, has restrict its applicability to current downstream processing. Microscale process techniques have recently emerged as effective tools for expediting bioprocess design in a cost-effective manner. ATPE in a microfluidic platform was therefore designed and tested for mAbs extraction, as an effective tool to accelerate bioprocess design and optimization. Furthermore, this platform has the potential of combining the process efficiency of ATPS with the reduced times and volumes associated with microfluidics, as well as the possibility to multiplex and parallel process in real downstream processes. In this way, we have develop a microfluidic channel-based toolbox for the rapid screening of antibody extraction conditions. Several microfluidic structures have been designed including a multiplexed structure that allows a simple negative-pressure driven rapid screening of up to 8 continuous extraction conditions simultaneously, using less than 20 μL of each phase forming solution per experiment. Results obtained from this device can be further applied in a second microfluidic structure (Figure 1) that integrates multiple-step continuous extraction protocols

Investigative activities for statistics learning with 1st grade Portuguese students

The relevance of data exploration in mathematics programmes at all levels of education led us to develop a learning experience with 1st grade students with the aim of investigating the contribution of investigative activities in the learning of statistics. To achieve this objective, the following research questions were outlined: How do students implement investigative activities when learning statistics? What difficulties do students have in carrying out investigative activities when learning statistics? Adopting a qualitative and interpretative approach, data were collected through students’ written records, the reflections of the teacher, and a written test applied before and after the learning experience. The results obtained suggest that students were able to carry out investigative activities when learning statistics although with some weaknesses, namely defining the topic and research questions, and analysing the data due to the greater complexity of the research proposed by them. Students were able to formulate conclusions, although in some groups the conclusions were underdeveloped. Students were most confident in data collection, organization, and representation activities, with limitations typical of their young age (e.g., written communication). Students also showed difficulties in managing group work and knowledge of statistics, notably concerning strategies of data organization and representation and statistical measures

Distance educational relationship and senses of belonging: the voices of students

In a viral society in which the social being claims the ability to maintain distance and the socially desirable representation of the body, in particular the face, claims its concealment, the distance educational relationship represents a critical area that deserves to be highlighted in the research agendas. This study aims to explore the sense of belonging of 98 students who attend a distance learning university. For this purpose, an open-ended questionnaire was applied, previously disclosed in closed groups on social networks. The students' sense of belonging was analysed through the types of connections they maintain with the campus, course, peers and teachers. The analysis of the narratives expresses a great diversity, density of experiences and expectations in the connections and senses of belonging. Attributing great importance to teachers in the appropriation of knowledge, it is essentially with their peers - other students - that the connections and sense of belonging acquire greater expressioninfo:eu-repo/semantics/publishedVersio

Las reformas curriculares de la disciplina de matemáticas en la enseñanza secundaria portuguesa a lo largo del siglo XIX

En este póster se presenta parte de una investigación más amplia acerca del lugar que el estudio de las matemáticas ocupan en los programas de enseñanza secundaria a lo largo de los siglos XIX y XX, más concretamente, en el período de 1835-1974 (Aires & Santiago, 2014)