Geochemistry and risk assessment of street dust in Luanda, Angola, a tropical urban environment

A total of 92 samples of street dust were collected in Luanda, Angola, were sieved below 100 μm, and analysed by ICP-MS for 35 elements after an aqua-regia digestion. The concentration and spatial heterogeneity of trace elements in the street dust of Luanda are generally lower than in most industrialized cities in the Northern hemisphere. These observations reveal a predominantly “natural” origin for the street dust in Luanda, which is also manifested in that some geochemical processes that occur in natural soils are preserved in street dust: the separation of uranium from thorium, and the retention of the former by carbonate materials, or the high correlation between arsenic and vanadium due to their common mode of adsorption on solid particles in the form of oxyanions. The only distinct anthropogenic fingerprint in the composition of Luanda's street dust is the association Pb–Cd–Sb–Cu (and to a lesser extent, Ba–Cr–Zn). The use of risk assessment strategies has proved helpful in identifying the routes of exposure to street dust and the trace elements therein of most concern in terms of potential adverse health effects. In Luanda the highest levels of risk seem to be associated (a) with the presence of As and Pb in the street dust and (b) with the route of ingestion of dust particles, for all the elements included in the study except Hg, for which inhalation of vapours presents a slightly higher risk than ingestion. However, given the large uncertainties associated with the estimates of toxicity values and exposure factors, and the absence of site-specific biometric factors, these results should be regarded as preliminary and further research should be undertaken before any definite conclusions regarding potential health effects are drawn

Construction of a disaster-support dynamic knowledge chatbot

This dissertation is aimed at devising a disaster-support chatbot system with the capacity to enhance citizens and first responders’ resilience in disaster scenarios, by gathering and processing information from crowd-sensing sources, and informing its users with relevant knowledge about detected disasters, and how to deal with them. This system is composed of two artifacts that interact via a mediator graph-structured knowledge base. Our first artifact is a crowd-sourced disaster-related knowledge extraction system, which uses social media as a means to exploit humans behaving as sensors. It consists in a pipeline of natural language processing (NLP) tools, and a mixture of convolutional neural networks (CNNs) and lexicon-based models for classifying and extracting disasters. It then outputs the extracted information to the knowledge graph (KG), for presenting connected insights. The second artifact, the disaster-support chatbot, uses a state-of-the-art Dual Intent Entity Transformer (DIET) architecture to classify user intents, and makes use of several dialogue policies for managing user conversations, as well as storing relevant information to be used in further dialogue turns. To generate responses, the chatbot uses local and official disaster-related knowledge, and infers the knowledge graph for dynamic knowledge extracted by the first artifact. According to the achieved results, our devised system is on par with the state-of-the- art on Disaster Extraction systems. Both artifacts have also been validated by field specialists, who have considered them to be valuable assets in disaster-management.Esta dissertação visa a conceção de um sistema de chatbot de apoio a desastres, com a capacidade de aumentar a resiliência dos cidadãos e socorristas nestes cenários, através da recolha e processamento de informação de fontes de crowdsensing, e informar os seus utilizadores com conhecimentos relevantes sobre os desastres detetados, e como lidar com eles. Este sistema é composto por dois artefactos que interagem através de uma base de conhecimento baseada em grafos. O primeiro artefacto é um sistema de extração de conhecimento relacionado com desastres, que utiliza redes sociais como forma de explorar o conceito humans as sensors. Este artefacto consiste numa sequência de ferramentas de processamento de língua natural, e uma mistura de redes neuronais convolucionais e modelos baseados em léxicos, para classificar e extrair informação sobre desastres. A informação extraída é então passada para o grafo de conhecimento. O segundo artefacto, o chatbot de apoio a desastres, utiliza uma arquitetura Dual Intent Entity Transformer (DIET) para classificar as intenções dos utilizadores, e faz uso de várias políticas de diálogo para gerir as conversas, bem como armazenar informação chave. Para gerar respostas, o chatbot utiliza conhecimento local relacionado com desastres, e infere o grafo de conhecimento para extrair o conhecimento inserido pelo primeiro artefacto. De acordo com os resultados alcançados, o nosso sistema está ao nível do estado da arte em sistemas de extração de informação sobre desastres. Ambos os artefactos foram também validados por especialistas da área, e considerados um contributo significativo na gestão de desastres

On bond mutual funds participation in the lending market

The purpose of this masterthesis is to examine which factors drive the decision of bond funds to lend their securities and the performance of those funds which lend relative to similar funds which do not. Overall, none of the variables studied impact the decision of funds to lend securities, and funds which lend perform similarly to non-lending funds. To further clarify the dependency of the return-lending attribute, funds were divided according to the permanent or non-permanent character of lending practices. Funds that alternate between lending and non-lending exhibited a small albeit negligible return penalty

On the preference for form and abstract architecture spaces with distinct geometric characteristics

Since at least the Greek classic period that thought, within the western civilizations, has been sharing a strict relationship with Euclidean principles, which have influenced and characterized it, leading to a specific type of reasoning and identity. In turn, as expressions of the mind, the forms that we have been thinking about and have brought to material reality, have been following these same Euclidean principles. Thought has shared also a closed relationship with architecture and architecture space form. A relationship that became even more pronounced with the incoming phenomenon of the Industrial Revolution with its standardization and mass production techniques and technologies. Ever since, the majority of architecture spaces that we have been thinking about and eventually building, follow and share Euclidean-orthogonal principles and relationships. However, with the arrival of the 20th and 21st centuries’ Digital Revolutions and their novel representation, visualization and production techniques and technologies, the forms that we think about and manage to produce, have achieved an unprecedented range of freedom, in which both Euclidean and non-Euclidean free forms are considered. This happening opened a pertinent and relevant thinking and discussion on whether humans, in their nature and within a valid freedom of choice, tend to prefer the long settled Euclidean, orthogonal-based architecture spaces, with all the elements that such geometry implies, namely, the presence of angular, sharp edges and vertices, or, on the contrary, they tend to prefer non-Euclidean, curved, rounded architecture spaces. This thesis proposes to address the problem of the preference for form, namely architecture space form, divided in two sub-problems that the literature review helped to identify: aesthetic judgements and approach-avoidance decisions, two judgements that, in turn, may rely in two knowledge ‘databases’: a subjective-based one, build through our life time sensible and rational experiences, and, a more objective-based one, which hides behind our genetic legacy and lays on basic evolutionary defense functions or mechanisms. We will approach this thesis Problem and Research Question, through (i) a free discourse on historic key events that, through our evolutionary stages, may have contributed to the fact that we have been closer to some elements, namely forms and architecture form, with certain geometric characteristics, over others; (ii) the evolution of aesthetics and our basic evolutionary defense functions or mechanisms, through qualitative and quantitative research methodologies, (iii) state-of-the-art review on the topic of preference for elements with distinct geometric characteristics, and (iv) our own developed experimental user study on abstract architecture spaces with distinct geometric characteristics at the contour level, which, based on the thesis two sub-problems, tried to validate our raised hypotheses. The results of this thesis suggest that humans prefer abstract architecture spaces with curved, rounded elements, rather than those equipped with angular, sharp ones. On the other hand, they were inconclusive on whether we prefer Euclidean-orthogonal or full non-Euclidean abstract architecture spaces, possibly due to familiarity (“mere-exposure”) and ‘strangeness’ effects. These results validate and partial validate hypotheses ‘H1’ and ‘H2’, respectively, the two major hypotheses of this thesis.Desde pelo menos o período grego clássico que o pensamento das civilizações ocidentais têm partilhado uma relação estreita com princípios Euclidianos, algo que tem influenciado e caracterizado este pensamento, orientando-o para uma forma específica de raciocínio e identidade. Por sua vez, enquanto expressões da mente, as formas que temos vindo a pensar e a trazer para a realidade material têm seguido estes mesmos princípios Euclidianos. Enquanto extensão do pensamento, o mesmo se tem aplicado à arquitetura, nomeadamente à sua forma. Esta relação tornou-se ainda mais pronunciada com a chegada do fenómeno da Revolução Industrial e as suas técnicas e tecnologias de estandardização e produção em série. Desde então, a maioria dos espaços de arquitetura que temos pensado e construído seguem e partilham princípios e relações ortogonais-Euclidianos. No entanto, com a entrada em cena das revoluções digitais dos séculos XX e XXI e as suas inovadoras técnicas e tecnologias de representação, visualização e produção, as formas que temos vindo a pensar e a conseguir produzir, atingiram um grau de liberdade sem precedentes, no qual entram em consideração tanto as formas Euclidianas como não-Euclidianas. Este acontecimento abriu uma discussão pertinente e relevante sobre se, na eventualidade de uma válida liberdade de escolha, os humanos efetivamente preferem os, tão presentes e enraizados, espaços de arquitetura ortogonais-Euclidianos, com todos os elementos que esta geometria implica, nomeadamente, a presença de arestas e vértices angulares e afiados, ou, pelo contrário, preferem espaços de arquitetura não-Euclidianos, com elementos curvos e arredondados. Esta tese de doutoramento propõe, neste sentido, abordar o problema da preferência pela forma, nomeadamente, pela forma dos espaços de arquitetura, dividido pelos dois sub-problemas que a revisão bibliográfica ajudou a identificar: Julgamentos estéticos e decisões de aproximação ou afastamento, dois julgamentos que, por sua vez, podem estar baseados em duas ‘bases de dados’ de conhecimento: uma subjetiva, construída ao longo das nossas experiências sensíveis e racionais, e, uma mais objetiva, que se esconde atrás do nosso legado genético e assenta em funções ou mecanismos básicos de defesa evolutiva. O Problema e a Pergunta de Investigação desta tese serão abordados através de (i) um discurso livre sobre eventos históricos chave que, ao longo da nossa evolução, possam ter contribuído para o facto de podermos ter mantido um maior grau de aproximação em relação a determinados elementos, nomeadamente, formas e a forma da arquitetura, com determinadas características geométricas, sobre outros; (ii) a evolução do estudo da estética e as nossas funções ou mecanismos básicos de defesa evolutiva, através metodologias de investigação qualitativa e quantitativa, (iii) a revisão do estado-da-arte sobre a preferência de elementos com características geométricas distintas e (iv) o desenvolvimento de um estudo experimental sobre espaços abstratos de arquitetura com características geométricas distintas ao nível do contorno, que, baseado nos dois sub-problemas desta tese, procurou validar as hipóteses de estudo levantadas. Os resultados desta tese sugerem que os humanos preferem espaços abstratos de arquitetura com elementos curvos e arredondados em relação àqueles dotados de elementos angulares e afiados. Por outro lado, foram inconclusivos quanto ao facto de podermos preferir espaços de arquitetura Euclidianos-ortogonais àqueles puramente não-Euclidianos. Estes resultados validam e validam parcialmente as hipóteses H1 e H2, respetivamente, as duas hipóteses principais desta tese de doutoramento

Is employment really polarizing? Evidence from the Portuguese Labor Market

Employment Polarization is often identified as one of the factors driving the growing wage inequality in western economies. But is employment polarization informative about wage inequality and is employment really polarizing? This is the general question driving this paper. By equating a job with an individual rather than an occupation, we re-assess whether Portuguese workers are increasingly concentrated in low and high-wage jobs relative to middle-wage jobs. For this purpose, we assign workers from the Quadros de Pessoal to real hourly wage bins with time-invariant thre sholds and find that, over time, workers increasingly concentrate in the upper bins and diverge from the lower bins, inconsistent with Employment Polarization. Turning to Wage Polarization analysis, we perform and extend the Foster-Wolfson test and find no evidence of wage polarization either.Ourresults contradict the literature and, most importantly, suggest that the channel through which Employment and Wage Polarization are connected is more complex than common lyassumed

Connect bridge management studio: a web-based application used to manage and test connect bridge servers

Connecting Software is a software development company focused on the development of integration solutions. For this, the company created a platform named Connect Bridge and some products based on this platform which provide an out-of-the box solution for the common integration issues faced by companies. The Connect Bridge (CB) is an integration platform mainly based on a server (usually named CB Server) that uses a plugin architecture to allow its users to connect to a variety of systems (e.g., Microsoft Exchange, SharePoint or Dynamics CRM). Each plugin (usually called as a connector), allows the platform to access a different target system. Connect Bridge platform is managed by two different applications, the Administration Tool and Query Analyzer. These two tools are old-fashioned and only compatible with Windows operating systems, which limits the number of customers that can use this platform. This project aims to solve these problems by creating a Single Page Web Application called Connect Bridge Management Studio which was developed using Angular and ASP.NET Core. At the end of this project, Connecting Software has a ready to deploy application that is capable of replacing Query Analyzer and Administration Tool in all their core features. The evaluation of this project was made comparing the existing tools with the CB Management Studio. Also, an evaluation with users was performed using the think-aloud technique and SUS test which presented satisfactory results. The present document describes the process followed to achieve this solution, focusing on the most critical aspects of its development and the faced challenges.A Connecting Software é uma empresa de desenvolvimento de software focada no desenvolvimento de soluções de integração. De modo a atingir este objetivo, a empresa criou uma plataforma chamada Connect Bridge e alguns produtos baseados na mesma que fornecem uma solução out-of-the-box para os problemas de integração mais recorrentes em empresas. O Connect Bridge (CB) é uma plataforma de integração que consiste principalmente em um servidor (geralmente chamado CB Server) que usa uma arquitetura de plugins para permitir que os seus utilizadores se conectem a uma variedade de sistemas (por exemplo, Microsoft Exchange, Microsoft SharePoint ou Dynamics CRM). Cada plugin (geralmente chamado de conector) permite que a plataforma aceda a um sistema diferente. A plataforma Connect Bridge é gerida através de duas aplicações distintas, denominadas por Administration Tool e Query Analizer. Estas duas ferramentas são antigas e compatíveis apenas com os sistemas operativos Windows, o que limitava o número de clientes que podiam usar essa plataforma para desenvolver as suas soluções de integração. Este projeto visa solucionar esses problemas criando uma aplicação Web chamada Connect Bridge Management Studio. Esta é uma Single Page Application desenvolvida usando as frameworks Angular e ASP.NET Core. No final deste projeto, a Connecting Software dispõe de uma aplicação pronta a ser lançada capaz de substituir o Query Analyzer e o Administration Tool. A avaliação desta solução foi efetuada a partir da comparação destas ferramentas com o CB Management Studio. Para além disso, efetuou-se uma avaliação com utilizadores utilizando a técnica think-aloud onde se obtiveram resultados satisfatórios. O presente documento descreve o processo seguido para alcançar esta solução, focando-se nos aspetos mais importantes do seu desenvolvimento e desafios enfrentados

MotionDesigner: a tool for creating interactive performances using RGB-D cameras

In the last two decades the use of technology in art projects has proliferated, as is the case of the interactive projections based on movement used in art performances and installations. However, the artists responsible for creating this work typically have to rely on computer experts to implement this type of interactive systems. The tool herein presented, MotionDesigner, intends to assist the role of the artistic creator in the design of these systems, allowing them to have autonomy and efficiency during the creative process of their own works. The proposed tool has a design oriented to these users so that it stimulates and proliferates their work, having an extensible nature, in the way that more content may be added further in the future. The developed software was tested with dancers, choreographers and architects, revealing itself as an aid and catalyst of the creative process.Desde há duas décadas que o uso da tecnologia em projetos artísticos tem proliferado cada vez mais, como é o caso das projeções interativas baseadas em movimento utilizadas em performances e instalações artísticas. No entanto, os artistas responsáveis pela criação destes trabalhos têm, tipicamente, de recorrer a especialistas em computadores para implementar este tipo de sistemas interativos. A ferramenta apresentada nesta dissertação, o MotionDesigner, pretende auxiliar o papel do criador artístico na conceção destes sistemas, permitindo que haja autonomia e eficiência no processo criativo das suas próprias obras. A ferramenta proposta possui um design orientado para estes utilizadores de modo a estimular e agilizar a criação autónoma deste tipo de obras e tem uma natureza extensível, na medida em que mais conteúdo pode ser adicionado no futuro. O software desenvolvido foi testado com bailarinos, coreógrafos e arquitetos, revelando-se como uma ajuda e um catalisador do processo criativo da suas obras interativas

Mechanical and optical studies for an extremely large telescope mid-infrared instrument

Extremely Large Telescopes are considered worldwide as one of the highest priorities in ground-based astronomy, since they have the potential to vastly advance astrophysical knowledge. ESO is building its own Extremely Large optical and infrared Telescope, the ELT. This new telescope will have a 39m main mirror and will be the largest optical telescope in the world, able to work at the diffraction limit. METIS, one of the first light instruments of the ELT, has powerful imaging and spectrographic capabilities on the thermal wavelengths. It will allow the investigation of key properties of a wide range of celestial objects. METIS is an extremely complex instrument, weighing almost 11t, and requiring high positioning and steering precisions. Here I present the ELT’s METIS’ Warm Support Structure. It consists of a seven leg elevation platform, an hexapod capable of providing METIS with sub-millimetre and arcsecond positioning and steering resolutions, and an access platform where personnel can perform in-situ maintenance activities. The structure weighs less than 5 t and is capable of surviving earthquake conditions with accelerations up to 5g. The current design is supported by FEM simulations in ANSYS®, and was approved for Phase C. I also study the impact of the Talbot effect on the optics of METIS. This near-field effect reimages high frequencies of the phase into the amplitude, having the potential to harm the High contrast imaging (HCI) modes of the instrument. I analyse the phase errors resulting from the surface form errors of optical elements and conclude that they have an impact of less than 3% on the amplitude considering the current specifications. Finally, I develop a way of replicating the behaviour of a vortex coronagraph with raytracing software. I use this to assess the straylight caused by this kind of coronagraphs

Repository conversations

For a long time, informal communication has played an important role in the process of creating and sharing scholarly knowledge. However, only a handful of initiatives have seriously attempted to exploit the advantages of informal communication processes as a complement to the classic mechanisms of scholarly communication. This article describes the developments that resulted from the DSpace-dev@University of Minho project, particularly, the ones that focus the Commenting add-on: an extension developed for the DSpace platform which aims at providing Institutional Repositories with informal communication capacities. The article also alludes to some ideas that can be taken as the basis for future developments about this subject, namely: to transform the current add-on into a cross-repository and cross-platform service; to make each comment have its own descriptive metadata in order to facilitate its discovery by search engines; and to improve significantly its graphical user interface