3,159 research outputs found
Molecular tools to dissect the role of Dmrt2a and Dmrt2b in the left-right axis formation in zebrafish
Dissertação para obtenção do Grau de Mestre em Genética Molecular
e BiomedicinaWe tend to view the vertebrate body as bilaterally symmetric, but in fact, this only happens from the outside. Internally, most of the organs from heart to liver are asymmetrically positioned. Skeleton and its associated muscles, symmetric structures of the vertebrate body, have its origins in the transient symmetric blocks of mesoderm called somites whereas the asymmetric morphogenesis of the internal organs is due to asymmetric gene expression in the lateral plate mesoderm (LPM).
Previous studies using Morpholino (MO) technology have shown that dmrt2a is involved in these two processes in zebrafish. When Dmrt2a levels are reduced, asymmetric gene expression in the LPM becomes randomized and symmetric gene expression in the presomitic mesoderm (PSM) is disrupted. The paralogous of dmrt2a, the fish specific dmrt2b has been shown to be involved in regulating asymmetric gene expression in the LPM as well.
Here we used the recent Transcription activator-like effector nucleases (TALENs) technology to generate dmrt2a and dmrt2b mutant alleles that will allow us in the future to uncover the downstream effectors of these transcription factors using high-throughput experiments. In addition, we overexpressed dmrt2a at the one-cell stage to characterize asymmetry versus symmetry phenotypes.
The results show clearly the ability of TALEN technology to generate mutant alleles in zebrafish. Nevertheless, dmrt2a and dmrt2b homozygous mutants developed so far fail to recapitulate their previously described MO phenotypes which raise the question on what molecular mechanism(s) allow(s) zebrafish to cope with frameshift mutations.
The overexpression of dmrt2a shows that a time window of opportunity during which symmetric embryonic territories are able to respond to asymmetric signals does exist during embryonic development
A stochastic modelling of the dynamical behaviour of highway bridge decks under traffic loads
In this paper an analysis methodology is developed to evaluate the dynamic response on highway bridge decks due to vehicles crossing on the rough pavement surfaces. The analysis methodology follows a statistical
model running in the time domain. The mathematical model simulates the bridge structure and the vehicle series as a system, the vehicle-bridge system. The bridge deck follows a straight beam model made discrete by finite elements and nodal concentrated masses, with vertical translations and in-plane rotations as degrees of freedom. The vehicle simulation uses concentrated parameters of mass, stiffness and damping. Four different types of vehicles are modelled as rigid masses connected by springs and dampers with one, two, four or five degrees of freedom. According to each vehicle model, translational and rotational displacements
are considered. The deck surface roughness is defined by a weakly stationary, second order and ergodic random process based on a well-known power spectrum density of road pavement profiles. The moving load is modelled by an infinite series of equal vehicles, regularly spaced, and running at constant velocity. Only steady-state response is considered. Response data are produced on reinforced concrete highway bridge decks made of a straight box girder cross section based on several spans and support arrangements. Conclusions are concerned with the fitness of the developed analysis methodology and the mathematical model adequacy. The influence of the vehicle type on the highway bridge decks dynamic behaviour was observed. The magnitude of the effects due to the interaction of the vehicles with an irregular pavement surface and their consequences about design and maintenance are investigated.Peer Reviewe
Fabrico de vigas compostas
Estágio realizado na Martifer - Construções Metalomecânicas, S.A. e orientado pelo Eng.º Pedro DuarteTese de mestrado integrado. Engenharia Mecânica. Faculdade de Engenharia. Universidade do Porto. 200
Who shot optical packet switching?
Looking at the volume of publications dealing with Optical Packet (OPS) and those dealing with Elastic Optical Networking (EON) in the period from 2000 to 2016, one clearly can observe that between 2004 and 2009 there is a boom of the OPS publications and then they start to diminish. At the same time, EON publications start to take-off (around 2011) and is steadily growing. EON is an emerging technology that may be considered as a killer technology in the sense that its performance, flexibility, associated cost, ease of deployment and marketing seem to be displacing OPS from the optical networking arena. The purpose of this paper is discuss if, effectively, EON is the killer technology of OPS. So then, besides review the EON technology, the paper analyzes its actual deployment possibilities.Peer ReviewedPostprint (author's final draft
Ethical Perspectives in AI: A Two-folded Exploratory Study From Literature and Active Development Projects
Background: Interest in Artificial Intelligence (AI) based systems has been gaining traction at a fast pace, both for software development teams and for society as a whole. This increased interest has lead to the employment of AI techniques such as Machine Learning and Deep Learning for diverse purposes, like medicine and surveillance systems, and such uses have raised the awareness about the ethical implications of the usage of AI systems. Aims: With this work we aim to obtain an overview of the current state of the literature and software projects on tools, methods and techniques used in practical AI ethics. Method: We have conducted an exploratory study in both a scientific database and a software projects repository in order to understand their current state on techniques, methods and tools used for implementing AI ethics. Results: A total of 182 abstracts were retrieved and five classes were devised from the analysis in Scopus, 1) AI in Agile and Business for Requirement Engineering (RE) (22.8%), 2) RE in Theoretical Context (14.8%), 3) Quality Requirements (22.6%), 4) Proceedings and Conferences (22%), 5) AI in Requirements Engineering (17.8%). Furthermore, out of 589 projects from GitHub, we found 21 tools for implementing AI ethics. Highlighted publicly available tools found to assist the implementation of AI ethics are InterpretML, Deon and TransparentAI. Conclusions: The combined energy of both explored sources fosters an enhanced debate and stimulates progress towards AI ethics in practice
Verification of performance degradation in a telecommunications system due to the uncertainty of human users in the loop
The intensive use of new technologies that cause more interactions between systems and the daily activities of human users is changing the focus on how network re- sources should be managed. However, these changes can create challenges related to the level of uncertainty that people introduce to the system. In this context, this research study seeks to determine whether people’s uncertainty influences network performance and how significant its impact is. For these purposes, a simulated case study of a Vehicle for Hire application designed to run over a network slicing of a fifth-generation (5G) network. The simulations compared call drop rates in several settings configured to represent different levels of uncertainty, introducing random alterations to free channel planning reserved for the handover process. The simulation results reveal that the uncertainty specifically introduced by people exerts a high negative impact on network performance, evidencing the need to develop an algorithm that considers this uncertainty when managing resources within the 5G network core.This work has been supported by the Spanish Government through project TRAINER-A (PID2020-118011GB-C21) with FEDER contribution. Moreover, it has been supported by the Spanish Thematic Network under contract RED2018-102585-T (Go2Edge) and by the aid granted by the Sinfoni project INV2733 of the Cooperative University of Colombia.Peer ReviewedPostprint (published version
Avaliação de parâmetros de qualidade da meloa ‘Gália’ (Cucumis melo L. var. reticulatus Naud. cv. galia) produzida em modo biológico vs. convencional
As problemáticas ambientais associadas ao setor agroalimentar impulsionam o consumidor a exigir produtos de maior qualidade com origem em práticas agronómicas económica, social e ambientalmente sustentáveis.
Neste estudo, com base em instrumentos científicos e metodologias de analise normalizadas, estabeleceu-se um ensaio em vaso, com vista á obtenção de meloa produzida em modo biológico e em modo convencional, avaliando-se comparativamente a sua produtividade e características comerciais.
Das meloas produzidas nos dois sistemas, avaliou-se ainda, a qualidade sensorial e físico-química, concretamente, no que respeita à textura, pH, teor de sólidos solúveis totais, humidade total, gordura bruta, celulose bruta, proteína bruta, cinza total, teor de sódio e nitritos, bem como o cálculo de extratos não azotados e avaliação calórica.
Comparando ambos os sistemas, a meloa produzida em modo biológico apresentou mais 42 % em teor de sólidos solúveis totais, mais 25 % de matéria seca, menos 60 % de nitritos, a melhor classificação atribuída pelo painel de provadores quanto à suculência, sabor doce e apreciação global, permitindo concluir que o modo de produção biológico, com menor produtividade, resulta em frutos mais nutritivos, mais doces, mais suculentos e, de um modo genérico, vão de encontro às espectativas e preferências do consumidor
Influence of preparation procedures on the phenolic content, antioxidant and antidiabetic activities of green and black teas
The influence of common tea preparation procedures (temperature, infusion time, consumption time interval and tea bag/loose-leaf) and the type of water used, on the total phenolic content (TPC), the radical scavenging activity and the alpha-glucosidase inhibitory activity were assessed. Higher TPC and antioxidant activity were obtained when using lower mineralized waters. Tea bags also evidenced higher antioxidant activity than loose-leaf samples. Under the same conditions (90 degrees C and five minutes of infusion time) green tea contains almost twice the quantity of polyphenols and the free radical scavenging ability of black tea. In the alpha-glucosidase assay all infusions were active (97-100 %). Furthermore, HPLC allowed to identify some of the polyphenols present in both teas and to monitor their composition change with time. After twenty-four hours, the antioxidant activity was maintained without significant changes, but a small decrease in enzyme inhibition was observed, although this activity was still very high.info:eu-repo/semantics/publishedVersio
Cultura, valores, ritos / rituais organizacionais: um estudo de caso na Universidade Estadual do Maranhão - UEMA /
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Sócio-Econômico.Análise dos valores, ritos e rituais predominantes da cultura organizacional da Universidade Estadual do Maranhão - UEMA, mediante a percepção de seu corpo docente pesquisado, ressaltando a importância para melhor identifica-los, o estabelecimento de relações de congruência e incongruência entre fatores e centros investigados e sugestões para a gestão da cultura da Universidade, através dos fatores: eficácia e eficiência, interação no trabalho, respeito ao docente e gestão, por Centro. Conclusões sobre os valores, ritos e rituais mais predominantes, por fator, relacionado com cada Centro e proposições a serem desenvolvidas pela UEMA, para melhor cumprir o seu papel com autonomia universitária e liberdade acadêmica como princípio
Civic movements, participation culture and city transformation: tension and cooperation in urban development
Em um contexto global de desconfiança quanto aos rumos tomados pela política institucional e seus gestores, muitos cidadãos buscam maneiras – individuais ou coletivas - possíveis de participar na tomada de decisão, de forma a garantir maior autonomia aos seus futuros e representatividade nas decisões. Entre o querer e o poder as distâncias são, todavia, bastante variáveis, e muitas vezes o desejo de colaborar se transforma em esforço para resistir e lutar contra os obstáculos impostos a uma verdadeira governação democrática.
A partir de uma atuação prévia do autor deste trabalho como cidadão interessado de forma individual ou em vários grupos cidadãos, surgiu a impressão de que, não fossem as resistências dos poderosos a uma participação intensamente democrática, as próprias administrações e políticas públicas (além da sociedade como um todo) poderiam ser muito beneficiadas pelo voluntarismo de tantos cidadãos em ajudar o desenvolvimento de sua cidade. Para isso, esta dissertação objetivou aprofundar o conhecimento e refletir sobre a atuação dos movimentos cívicos no desenvolvimento urbano em relação aos diferentes modelos de governação e à cultura de participação à escala local.
Para alcançar esse objetivo, foram escolhidos oito casos (seis no Brasil e dois em Portugal) com diferentes níveis de participação (identificados por vários autores) ofertada pelo poder público e métodos de ação ou reação vinda por parte dos cidadãos. Parte desses casos foi acompanhada pelo autor, enquanto outros tiveram suas informações angariadas por meio da pesquisa bibliográfica.
Ao fim da análise dos casos à luz dos conceitos teóricos e do cruzamento de seus resultados, o trabalho percebeu a necessidade de uma reinterpretação do contributo da “escada de participação cidadã” de Arnstein (1969), a qual foi feita com inclusão de informações relacionadas ao tipo de governação e a postura (predominante) adotada pelos cidadãos. Dessa forma, a hipótese de fortalecimento da sociedade mediante os esforços cívicos foi confirmada com muitos valores sociais positivos resultantes como as novas relações pessoais, os novos aprendizados, o fortalecimento da coletividade, o afeto e o senso de pertencimento gerado com o espaço.In a global context of distrust to the paths taken by institucional policy and its managers, many citizens look for ways to participate – individually or collectively - in decision-making, as a way to ensure greater authonomy to their futures and representativity in the decisions. Between wanting and being able to there are, however, variant distances and many times the will to collaborate becomes effort to resist and fight agains imposed obstacles to a true democratic governance.
Starting from previous acting of the author of this work as activist/interested citizen as individual or in citizen groups, a impression has arised that, if not by the resistance of the powerful agains an intense democratic participation, even public policies and government (besides society as a whole) could be greatly benefitted from the voluntarism of so many citizens to help the development of their city. For this, this thesis aimed to deepen the knowledge and reflect over the way of acting of civic movements for urban development in relation to different governance models and participation levels offered by public sector.
To reach this objective, it was chosen eight cases (six in Brazil and two in Portugal) with different participation levels (that were recognized by many authors before) offered by public power and action or reaction methods by citizens. Some of these study cases had their developments followed by the author, while others had their informations collected from bibliographical research.
By the end of case analysis according to theoretical concepts and the intersection of its results, the work perceived the need for a reinterpretation of the contribution of Arnstein “ladder of citizen participation”, that was made with inclusion of information related to governance type and (predominant) position adopted by citizens. In this way, the hypothesis of society strengthening through civic efforts was validated by many resulting positive social values like the new personal relations, new knowledges and learning, strengthening of collectivity and the affect and belonging sense generated with the space.Mestrado em Planeamento Regional e Urban
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