On the Hill estimator: a comparison of methods

Extreme value theory (EVT) deals with the occurrence of extreme phenomena. The tail index is a very important parameter appearing in the estimation of the probability of rare events. Under a semiparametric framework, inference requires the choice of a number k of upper order statistics to be considered. This is the crux of the matter and there is no definite formula to do it, since a small k leads to high variance and large values of k tend to increase the bias. Several methodologies have emerged in literature, specially concerning the most popular Hill estimator (Hill, 1975). In this work we compare through simulation well-known procedures presented in Drees and Kaufmann (1998), Matthys and Beirlant (2000), Beirlant et al. (2002) and de Sousa and Michailidis (2004), with a heuristic scheme considered in Frahm et al. (2005) within the estimation of a different tail measure but with a similar context. We will see that the new method may be an interesting alternative.

Solving large 0–1 multidimensional knapsack problems by a new simplified binary artificial fish swarm algorithm

The artificial fish swarm algorithm has recently been emerged in continuous global optimization. It uses points of a population in space to identify the position of fish in the school. Many real-world optimization problems are described by 0-1 multidimensional knapsack problems that are NP-hard. In the last decades several exact as well as heuristic methods have been proposed for solving these problems. In this paper, a new simpli ed binary version of the artificial fish swarm algorithm is presented, where a point/ fish is represented by a binary string of 0/1 bits. Trial points are created by using crossover and mutation in the different fi sh behavior that are randomly selected by using two user de ned probability values. In order to make the points feasible the presented algorithm uses a random heuristic drop item procedure followed by an add item procedure aiming to increase the profit throughout the adding of more items in the knapsack. A cyclic reinitialization of 50% of the population, and a simple local search that allows the progress of a small percentage of points towards optimality and after that refines the best point in the population greatly improve the quality of the solutions. The presented method is tested on a set of benchmark instances and a comparison with other methods available in literature is shown. The comparison shows that the proposed method can be an alternative method for solving these problems.

Autoimmune diseases and pregnancy: analysis of a series of cases

BACKGROUND: An autoimmune disease is characterized by tissue damage, caused by self-reactivity of different effector mechanisms of the immune system, namely antibodies and T cells. All autoimmune diseases, to some extent, have implications for fertility and obstetrics. Currently, due to available treatments and specialised care for pregnant women with autoimmune disease, the prognosis for both mother and child has improved significantly. However these pregnancies are always high risk. The purpose of this study is to analyse the fertility/pregnancy process of women with systemic and organ-specific autoimmune diseases and assess pathological and treatment implications. METHODS: The authors performed an analysis of the clinical records and relevant obstetric history of five patients representing five distinct autoimmune pathological scenarios, selected from Autoimmune Disease Consultation at the Hospital of Braga, and reviewed the literature. RESULTS: The five clinical cases are the following: Case 1-28 years old with systemic lupus erythematosus, and clinical remission of the disease, under medication with hydroxychloroquine, prednisolone and acetylsalicylic acid, with incomplete miscarriage at 7 weeks of gestation without signs of thrombosis. Case 2-44 years old with history of two late miscarriages, a single preterm delivery (33 weeks) and multiple thrombotic events over the years, was diagnosed with antiphospholipid syndrome after acute myocardial infarction. Case 3-31 years old with polymyositis, treated with azathioprine for 3 years with complete remission of the disease, took the informed decision to get pregnant after medical consultation and full weaning from azathioprine, and gave birth to a healthy term new-born. Case 4-38 years old pregnant woman developed Behcet's syndrome during the final 15 weeks of gestation and with disease exacerbation after delivery. Case 5-36 years old with autoimmune thyroiditis diagnosed during her first pregnancy, with difficult control over the thyroid function over the years and first trimester miscarriage, suffered a second miscarriage despite clinical stability and antibody regression. CONCLUSIONS: As described in literature, the authors found a strong association between autoimmune disease and obstetric complications, especially with systemic lupus erythematosus, antiphospholipid syndrome and autoimmune thyroiditis.

An innovative framework for probabilistic-based structural assessment with an application to existing reinforced concrete structures

A novel framework for probabilistic-based structural assessment of existing structures, which combines model identification and reliability assessment procedures, considering in an objective way different sources of uncertainty, is presented in this paper. A short description of structural assessment applications, provided in literature, is initially given. Then, the developed model identification procedure, supported in a robust optimization algorithm, is presented. Special attention is given to both experimental and numerical errors, to be considered in this algorithm convergence criterion. An updated numerical model is obtained from this process. The reliability assessment procedure, which considers a probabilistic model for the structure in analysis, is then introduced, incorporating the results of the model identification procedure. The developed model is then updated, as new data is acquired, through a Bayesian inference algorithm, explicitly addressing statistical uncertainty. Finally, the developed framework is validated with a set of reinforced concrete beams, which were loaded up to failure in laboratory.

Assistive locomotion strategies for active lower limb devices

Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Eletrónica Médica)

Physicochemical properties and antioxidant capacity of propolis of stingless bees (Meliponinae) and Apisfrom two regions of Tocantins, Brazil

ABSTRACTThe composition of propolis depends on time, vegetation and the location of the collection area. The objective of this study was to determine the physicochemical characteristics, the concentration of phenol compounds and the antioxidant capacity of propolis of native stingless bees (Meliponinae)and Apis from the State of Tocantins. Extraction with 80% ethanol (v/v) was performed in order to obtain the extracts. Parameters examined were: propolis mass loss by desiccation at 105 ºC, ashes, wax concentration and pH. Furthermore, the propolis antioxidant activity was measured, as well as the total concentration of phenol compounds. The extracts were also analyzed by high performance liquid chromatography. The total concentration of phenol compounds varied between 121.78 and 631.29 (mg GAE g-1). The antioxidant activity expressed by the value of CE50 varied between 29.81 and 845.38 µg mL-1. High performance liquid chromatography analysis allowed us to infer the existence of phenol compounds. The results indicated that the studied propolis samples constitute good sources of natural antioxidants. The variety of phenol compounds identified in this study, and the diverse biological functions reported in literature for these compounds indicated that this stingless bee propolis (Meliponinae) and Apis has a high pharmacological potential.

Cultural studies as the new humanities

The purpose of this study is to argue that Cultural Studies may be regarded as the new humanities. Cultural Studies focus on ethnic, post-colonial, communication, anthropological, ethnographic and feminist studies, and only ‘very marginally’ have they shown an interest in literature and literary studies (Aguiar & Silva, 2008). But those fields, which ‘Social Science’ rather than the ‘Arts’ have invested in (Ibid., p. 254), are the touchstone of modernity. Today, the concept we have of humankind is, to a large extent, played out in these areas. The questioning of both humankind and modernity has as backdrop the technologically-driven shift of culture from word to image (Martins, 2011 a). My proposal takes into account this debate, while underscoring how Cultural Studies are engaged in what is current and contemporary, which means, in the present and everyday life.

A dimensão interna da responsabilidade social nas organizações: equilíbrio entre o trabalho e a vida familiar

Dissertação de mestrado em Sociologia (área de especialização em Organizações e Trabalho)

Monitorização do risco de dificuldades de aprendizagem específicas na leitura de alunos do 2.º ao 4.ºano no contexto do modelo de resposta à intervenção

Dissertação de mestrado em Educação Especial (área de especialização em Dificuldades de Aprendizagem Específicas)

Ajustamento da criança à separação ou divórcio dos pais

Objetivo: O presente artigo procura relacionar e analisar evidências empíricas e teóricas sobre o impacto e os fatores associados ao impacto da separação ou divórcio dos pais no ajustamento da criança. Método: Realizou-se uma revisão agregativa da literatura, recorrendo às palavras-chave “divorce adjustment”, “child divorce” e “divorce impact”, nas bases de dados JSTOR, PsycInfo, SciELO e Medline e em livros da especialidade. Resultados: Respostas adaptativas e desadaptativas da criança são descritas, assim como potenciais resultados positivos. São principalmente discutidos os fatores mediadores e moderadores frequentemente referenciados na literatura no impacto da separação ou divórcio dos pais no ajustamento da criança. Entre esses estão: características da criança, problemas financeiros, sintomatologia psicopatológica dos pais, qualidade das práticas parentais e conflito interparental. Conclusão: Com base nas evidências empíricas e perspectivando o divórcio como uma transição desenvolvimental, levantamos a hipótese de que os problemas de ajustamento apresentados pelas crianças com pais divorciados possam ser mais bem explicados por outros fatores do que pelo divórcio/separação per se. Finalmente assumimos uma inovação conceptual de que essa transição familiar pode significar uma oportunidade de crescimento e de promoção desenvolvimental.

A comparative study of the physical, chemical and microbiological status of soils, as influenced by conventional and reduced tillage

Historically, shifts to reduced and no-tillage management for production of crops were fostered by needs to decrease soil erosion and loss of organic matter, reduce fuel and labour costs and conserve soil water, as compared with conventional fallow tillage management. Recent interest in maintaining soil quality has been stimulated by a renewed awareness of the importance of soil condition to both the sustainability of agricultural production systems and environmental quality (Doran and Parkin, 1996). The aim of this project was to determine the impact on the physical, chemical and microbiological status of the soil of conventional and reduced tillage. It has been suggested that the reduced soil disturbance associated with the tine cultivator improves soil structure, increases nutrient content in the top 10cm of soil, increases microbial activity and improves physical characteristics. From this study it was determined that the environmental benefits linked to reduced tillage in literature, did not develop in the first two years of this programmes implementation. The results of this study determined that soil nutrients did not increase in concentration in the top 10 cm of soil under reduced cultivation. The only exception was exchangeable potassium. As potassium is not a mobile nutrient its movement is dependent on soil disturbance, therefore under reduced cultivation its concentration was allowed to accumulate in the upper horizon of the soil profile. Microbial activity was greater in the conventionally tilled treatments, as determined by total aerobic bacterial numbers. This could be due to the increased rates of soil aeration in this treatment. Numbers of aerobic bacteria were greater in the conventional tillage treatments at both incubation temperatures of 22 and 32° C. The physical characteristics of the soil determined, indicate that below the depth of soil cultivation, cone penetration resistance increases. Therefore the reduced cultivation treatments would be more prone to soil compaction, higher in the soil profile.

Els agrocombustibles a Catalunya : mecanismes i efectes de l'europeïtzació en la política pública

En els darrers temps els agrocombustibles s’han promocionat com una alternativa als combustibles fòssils,adquirint un pes important en les agendes polítiques internacionals. Les dues grans potències econòmiques mundials, els Estats Units i la Unió Europea, han impulsat els agrocombustibles a través de diferents estratègies; plans, legislació, però també amb excempcions fiscals i obligacions de barreja amb combustibles fòssils. En aquest marc, Catalunya va ser de les comunitats autònomes de l’Estat espanyol pioneres en la potenciació d’experiències de producció i consum d’agrocombustibles. A partir de l’anàlisi de la política i el debat a Catalunya es pot destacar la gran influència de l’esfera europea a través de diversos mecanismes en el procés, el que s’ha anomenat en la literatura com europeïtzació. Darrerament Europa s’ha convertit en un important centre de producció de polítiques públiques, especialment en polítiques ambientals i agrícoles a partir dels anys 80. És per aquest motiu que resulta rellevant conèixer les dinàmiques europees en una política complexa com la dels agrocombustibles a Catalunya, que presenta components energètics, però també amb altres aspectes relacionats amb el món agràri i el medi ambient.

Traduccions cantables per a corals infantils catalanes: el repertori anglès-català del SCIC

En primer lloc els objectius que s’estableixen en aquest estudi són: Valorar la importància de la melodia, dels accents i la musicalitat del text en les cançons traduïdes analitzades. Plantejar la necessitat de la traducció de cançons infantils. Analitzar les traduccions existents de l’anglès al català del repertori de cançons infantils que es canten a les corals infantils. Relacionar poesia infantil i cançó. Visualitzar l’ús de la cançó infantil per a l’ensenyament dels infants, tant pel que fa a la transmissió de valors com per a l’ensenyament de llengües. La metodologia utilitzada fa referència a dos aspectes. El mètode qualitatiu amb la lectura d’articles i la bibliografia seleccionada i el mètode quantitatiu amb l’anàlisi de tres entrevistes i vint-i-una enquestes a responsables de corals infantils. En aquest estudi ofereixo l’estat de la qüestió sobre la traducció de cançons, amb especial atenció a la traducció de cançons per ser cantades. Després s’aborda la traducció de cançons infantils per ser cantades, per acabar especificant el tema d’aquest treball d’investigació en concret: la traducció de cançons infantils per ser cantades, amb l’estudi de traduccions de l’anglès al català de cançons cantades per corals infantils de Catalunya, i se n’ubica el context: el moviment coral infantil a Catalunya. Per a la confecció d’aquest estudi s’ha fet un recull de vint-i-set cançons traduïdes (anglès-català) que canten les corals infantils de Catalunya aplegades en el Secretariat de Corals Infantils de Catalunya (SCIC). Se n’ha seleccionat les cançons traduïdes de l’anglès al català, incloent-hi la partitura, la lletra original i la traducció. Aquest recull permet establir un lligam entre la traducció, la música i la pedagogia musical a Catalunya, els tres eixos principals d’aquest treball. D’aquestes cançons se n’han analitzat tres seguint els criteris establerts per autors com Peter Low, per la seva àmplia experiència en la traducció de música vocal. Els criteris són referents al ritme, rima, cantabilitat, naturalitat i sentit. Per tal de fer aquest estudi es van portar a terme tres entrevistes a traductors de cançons infantils: Enriqueta Anglada, Maria Martorell i Josep Vigo. Per valorar l’ús de cançons traduïdes dins del moviment coral infantil en l’actualitat i de manera més global, el treball inclou una enquesta, adreçada a directors de cors infantils, resposta per 21 cors. Aquestes enquestes palesen els canvis produïts amb el temps respecte a la necessitat de traduir cançons, ja que actualment la traducció no és tant important tot i que es continua valorant la seva importància, sobretot per afavorir la comprensió del que es canta. Però alhora es referma el desig de cantar en l’idioma original (especialment en el cas de l’anglès), quan aquest idioma l’entén qui dirigeix o interpreta la cançó, quan aquest fet es veu com a repte, o quan es prioritza la relació original entre música i text.

Del teatre líric a la cançó popular : construcció social a partir de la música en València (1900-1959)

El text que es mostra a continuació resumeix el treball realitzat en la primera fase de recerca del projecte titulat provisionalment "Del teatre líric a la cançó popular: construcció social a partir de la música en València (1900-1959)". Aquest treball ha tingut una durada de set mesos entre febrer i agost de 2009. El projecte pretén dibuixar les línies que uneixen teatre líric i cançó popular fent especial èmfasi en els mecanismes de creació d'identitat de gènere, que va envoltar tot aquest procés. Per aquests motius, la recerca está construïda sobre dos eixos: entrevistes amb les fonts orals i buidatge dels principals fons bibliogrífics per a l'estudi de les fonts primàries i secundàries del primer període analitzat (1931-1959), focalitzat en els pobles que envolten la ciutat de València. Les conclusions apunten cap a una clara vinculació entre teatre líric i cançó popular, així com la utilització dels esdeveniments musicals amb finalitats conformadores de rols socials per part de les institucions sociopolítiques. Les diferències entre fonts primàries i fonts orals assenyalen una naturalització de la desigualtat de gènere a través de la música que han arribat fins als nostres dies, per la qual cosa és necessari l'estudi i anàlisi de la memòria musical.

Modulacions i desplaçaments rítmics

Modulacions i desplaçaments ens permet endinsar‐nos a la vesant més rítmica de la música, de la mà d’uns quants conceptes teòrics referents a alguns dels recursos utilitzats a la música moderna. A més dels conceptes teòrics també podrem trobar diferents exemples sonors molt representatius. Aquest treball ha de ser una eina d’ajuda per a la comprensió i assimilació d’aquests conceptes, en cap cas ha de ser una dificultat o entrebanc. L’assimilació d’aquests ens pot obrir les portes a una gran quantitat de recursos rítmics, ja sigui a nivell individual com a interpret o a nivell col·lectiu com a banda.