Complex-mass shell renormalization of the higher-derivative electrodynamics

We consider a higher-derivative extension of QED modified by the addition of a gauge-invariant dimension-6 kinetic operator in the U(1) gauge sector. The Feynman diagrams at one-loop level are then computed. The modification in the spin-1 sector leads the electron self-energy and vertex corrections diagrams finite in the ultraviolet regime. Indeed, no regularization prescription is used to calculate these diagrams because the modified propagator always occurs coupled to conserved currents. Moreover, besides the usual massless pole in the spin-1 sector, there is the emergence of a massive one, which becomes complex when computing the radiative corrections at one-loop order. This imaginary part defines the finite decay width of the massive mode. To check consistency, we also derive the decay length using the electron--positron elastic scattering and show that both results are equivalent. Because the presence of this unstable mode, the standard renormalization procedures cannot be used and is necessary adopt an appropriate framework to perform the perturbative renormalization. For this purpose, we apply the complex-mass shell scheme (CMS) to renormalize the aforementioned model. As an application of the formalism developed, we estimate a quantum bound on the massive parameter using the measurement of the electron anomalous magnetic moment and compute the Uehling potential. At the end, the renormalization group is analyzed.Comment: 10 pages, 2 figures, replaced with published versio

Attention Mechanisms in the Classification of Histological Images

Recently, there has been an increase in the number of medical exams prescribed by medical doctors, not only to diagnose but also to keep track of the evolution of pathologies. In this sense, one of the medical specialties where the mentioned increase in the prescription rate has been observed is oncology. In this regard, not only to efficiently diagnose but also to monitor the evolution of the mentioned diseases, CT (Computed Tomography) scans, MRIs (Magnetic Resonance Imaging), and Biopsies are imaging techniques commonly used. After the exams are performed and the results retrieved by the respective health professionals, their analysis and interpretation are mandatory. This process, carried out by medical experts, is usually a time-consuming and tiring task. In this sense and to reduce the workload of these experts and support decision making, the research community start proposing several computer-aided systems, whose primary goal is to efficiently distinguish between healthy images and tumoral ones. Despite the success achieved by these methodologies, it become evident that the distinction of the two mentioned image categories (healthy and not-healthy) was associated with small regions of the images, and therefore not all image regions were equally important for diagnostic purposes. In this line of thinking, attention mechanisms start being considered to highlight important regions and neglect unimportant ones, leading to more correct predictions. In this thesis, we aim to study the impact of such mechanisms in the extraction of features from histopathological images of the epithelium from the oral cavity. In order to access the quality of the generated features for diagnostic purposes, those features were used to distinguish healthy from cancerous histopathological images.Recentemente, tem-se observado uma tendência crescente no número de exames médicos prescritos por médicos, no sentido de diagnosticar e acompanhar a evolução de patologias. Deste modo, uma das especialidades médicas onde a referida taxa de prescrição se assinala bastante elevada é a oncologia. No sentido de não só diagnosticar com eficácia, mas também para que a evolução das patologias seja devidamente seguida, é comum recorrer-se a técnicas de imagiologia como TACs (Tomografia Axial Computorizadas), RMs (Ressonâncias Magnéticas) ou Biópsias. Após a recepção dos respectivos exames médicos é necessário a sua análise e interpretação pelos profissionais competentes. Este processo é frequentemente moroso e cansativo para estes profissionais. No sentido de reduzir o labor destes profissionais e apoiar a tomada de decisão, começaram a surgir na literatura diversos sistemas computacionais cujo objectivo é distinguir imagens saudáveis de imagens não-saudáveis. Apesar do sucesso alcançado por estes sistemas, rapidamente se verificou que a distinção das duas classes de imagens é dependente de pequenas regiões, neste sentido nem todas as regiões constituintes da imagem são igualmente importantes para a distinção acima indicada. Posto isto, foram considerados mecanismos de atenção no sentido de maior importância dar a porções relevantes da imagem e negligenciar menos importantes, conduzindo a previsões mais correctas. Nesta dissertação pretende-se fazer um estudo do impacto destes mecanismos na extracção de features de imagens histopatológicas da mucosa oral. No sentido de avaliar a qualidade das features extraídas para o diagnóstico, estas são usadas por classificadores para a distinção de imagens saudáveis e cancerígenas

Susceptibility assessment to different types of landslides in the coastal cliffs of Lourinhã (Central Portugal)

The coastal zone of Lourinhã (located in Central Portugal) is characterized by beach–cliff systems,where beaches are narrowand cliffs have notorious slope instability. These cliffs evolve by different types of landslides,which are one of the main sources of natural hazard and risk in this coastal region. In this work, aerial photo interpretation and a systematic field survey were performed in order to obtain an inventory of landslides of the following types: rotational slides, translational slides and debris flows. The entire coast was then split into 261 terrain mapping units. For each unit, landslide predisposing factors were derived and classified: cliff elevation, slope angle (maximum, mean and standard deviation), potential solar radiation, slope curvature (profile and plan), lithological units and geologic structure. The predictive susceptibility models were computed for each type of landslide using a bi-variate statisticalmethod — the Information ValueMethod. The degree of fit and the predictive capacity of the models were assessed using the Effectiveness Ratio, the standard Receiver Operator Characteristic curves and the respective Area Under Curve. Results showthat each landslide typology occurs in particular terrain conditions. Individual susceptibilitymodels evidence better predictive capacity than susceptibility model for total landslides.info:eu-repo/semantics/publishedVersio

Beach response to high energy wave climate: a case study in the portuguese west coast

Portugal’s western coast is a wave-dominated rocky coast with a semidiurnal mesotidal regime. The wave climate is highly conditioned by the Atlantic Ocean’s atmospheric circulation, which results in a seasonalchange in wave patterns. Storms are frequent during winter and can reach 10-m wave heights with a 5-year recurrence period. Four profile monitoring campaigns were carried out in December 2005, January and May 2006 using a GPS and a total station to evaluate the response of three different beach systems to high wave climate events, comparing pre-storm wave, morphology and sediment characteristics with the modifications induced in the system after the storm event. A series of 64 beach profiles is analysed in terms of sediment textural properties, volume, slope, surf similarity index and dimensionless fall velocity parameters’ variability. Each beach system’s modal and limit morphological behaviours are established according to Wright and Short’s morphodynamic model.La costa oeste de Portugal es una costa rocosa dominada por olas y con un régimen mesomareal semidiurno. El clima marítimo está altamente condicionado por la circulación atmosférica del océano Atlántico y presenta una variabilidad estacional en el régimen de oleaje. Las tormentas son frecuentes durante el invierno y pueden alanzar alturas de ola de 10 m con una recurrencia de 5 años. Se han hecho cuatro campañas de control en tres playas, mediante el uso de GPS diferencial y estación total con el objetivo de evaluar su respuesta a sendos episodios de alta energía. Se comparan los cambios en la morfología y en la textura sedimentaria antes y después de cada temporal. Para ello se realizaron 64 perfiles de playa y se han analizado las variaciones en la textura del sedimento, el volumen, la pendiente, el índice de surf similarity y el parámetro adimensional de caída del sedimento. Con todo ello ha podido establecerse el comportamiento morfológico modal y extremo de dichas playas según el modelo de Wright y Short.info:eu-repo/semantics/publishedVersio

A Markovian model for ATM traffic generation

Many different traffic sources are transmitted simultaneously using the Asynchronous Transfer Mode (ATM) over the Broadband Integrated Services Digital Network (B-ISDN). Because of the ATM traffic statistical characteristics, the resource allocation in B-ISDN must be related to traffic parameters and the quality of service negotiated in the establishment of each call. A model for ATM traffic characterisation and generation control of the calls and cells is proposed. Traffic parameters calculated analytically and by simulation are compared

A resilience checklist to evaluate coastal dune vulnerability

The aim of the proposed resilience checklist is to easily evaluate foredune vulnerability when applied to management. It focus on: (i) the definition of the level of pressure for each use in relation to the foredune resilience threshold, (ii) the direct identification of the system components more vulnerable and (iii) the recognition of management readjustments needed, in order to prevent or minimise impacts. The resilience checklist structure is based on a selection of relevant coastal dune vulnerability descriptors, giving information about the system sensitivity and resilience. All variables selected describe observable signs of foredune degradation or regeneration and are related to system elements susceptible of receiving management intervention. hree major degrees of biophysical vulnerability are recognised: a) Degree 0 - low sensitivity and resilience threshold not exceeded; b) Degree 1 - variable sensitivity and at the resilience threshold; c) Degree 2- high sensitivity and resilience threshold exceeded. Each degree takes into account the system’s level of degradation and the corresponding desirable level of conservation. The application example- Mira’s beach southern sector- is a site under a very high summer pressure (seaside recreation and tourism). Three management phases were monitored, between 1996 and 1998. Checklist results show dune management inefficiency and an ineffective sand retention by vegetation as determinants to this foredune site vulnerability and that a planting program is still in need. However, a clear vulnerability decrease in this site was recognised.info:eu-repo/semantics/publishedVersio

A perplexidade como abertura do pensamento num “mundo fora dos eixos”

O assombro e a perplexidade diante de uma “realidade brasileira” que parece “fora dos eixos” é o ponto de partida deste artigo, que problematiza os limites da nossa compreensão e busca entender o que as forças ultraconservadoras perceberam na realidade – que nós não tínhamos percebido –, que possibilitou a essas forças dirigirem os acontecimentos e assumirem as rédeas dos fluxos de produção da realidade. A demonstração de como o nosso sistema social chegou ao seu limite histórico – que evidencia o esgotamento das condições para integração pelo trabalho e coesionamento social pelas regras democráticas e pelas políticas públicas construídas ao longo do século XX – permite elucidar a nova dinâmica da realidade brasileira e explicar a radical guinada das elites brasileiras, que migraram da estratégia democrática de gestão negociada das contradições sociais para uma estratégia autoritária de gestão bélica dessas contradições

Diferenças na actuação dos bancos comerciais privados e públicos: o caso da Caixa Geral de Depósitos

Pretende-se com este estudo apurar a diferenciação na actuação dos bancos comerciais privados e públicos, tendo como principal objeto em análise, a actuação da Caixa Geral de Depósitos. O estudo foi desenvolvido em dois períodos distintos, 1999 (expansão) e 2010 (crise) de forma a apurar com maior rigor as diferenciações da actuação da Caixa Geral de Depósitos em ambos contextos. Tendo em conta a pluralidade das variáveis (rácios) utilizadas no estudo, foi utilizada a análise de cluster, auxiliado pela ferramenta do software Statistical Package for the Social Sciences (SPSS). Concluiu-se que a Caixa Geral de Depósitos apresentou-se mais próximo dos pressupostos que regem a actuação do banco público no ano 1999 do que no ano 2010.The aim of this study was to determine differentiation in the activities of private and public commercial banks, the main subject under review, the performance of Caixa Geral de Depósitos. The study was conducted in two distinct periods, 1999 (expansion) and 2010 (crisis) in order to determine more accurately the differences in performance of Caixa Geral de Depósitos in both contexts. Given the plurality of variables (ratios) used in the study, we used cluster analysis, aided by software tool Statistical Package for Social Sciences (SPSS). Was concluded that the CGD appeared closer to the assumptions governing the conduct of public bank in the year 1999 than in 2010

Fracture-based interface model for NSM FRP systems in concrete

This paper introduces a numerical simulation tool using the Finite Element Method (FEM) for near-surface mounted (NSM) strengthening technique using fibre reinforced polymers (FRP) applied to concrete elements. In order to properly simulate the structural behaviour of NSM FRP systems there are three materials (concrete, FRP and the adhesive that binds them) and two interfaces (FRP/adhesive and adhesive/concrete) that shall be considered. This work presents the major details of a discontinuous-based constitutive model which aims at simulating NSM FRP interfaces implemented in the FEMIX FEM software. This constitutive model was adapted from one available in the literature, originally employed for fracture simulation in meso-scale analyses of quasi-brittle materials, which is based on the classical Flow Theory of Plasticity combined with fracture mechanics concepts. The most important features of the implemented constitutive model are the consideration of both fracture modes I and II and the possibility of performing 2D and 3D analysis. In the end, results based on FEM simulations are presented with the aim of investigating the soundness and accuracy of the constitutive model to simulate NSM FRP systems’ interfaces