Multi-agent Simulation of Bilateral Contracting in Competitive Electricity Markets

Traditional vertically integrated power utilities around the world have evolved from monopoly structures to open markets that promote competition among suppliers and provide consumers with a choice of services. Market forces drive the price of electricity and reduce the net cost through increased competition. Electricity can be traded in both organized markets or using forward bilateral contracts. This article focuses on bilateral contracts and describes some important features of an agent-based system for bilateral trading in competitive markets. Special attention is devoted to the negotiation process, demand response in bilateral contracting, and risk management. The article also presents a case study on forward bilateral contracting: a retailer agent and a customer agent negotiate a 24h-rate tariff.

Luiz Pacheco : maldição e consagração no meio literário português

Tese apresentada para cumprimento dos requisitos necessários à obtenção do grau de Doutor em Sociologia e Economia Histórica

Using children’s literature in ELT: A story-based approach

There has been a growing interest in the role of children’s literature in language teaching since the 80s, when the communicative approach made it possible to bring stories into the classroom (Garvie, 1990). It is undeniable that storytelling has many benefits. Not only are children naturally drawn to stories, but they are also an effective and enjoyable way to teach and learn. This article presents the findings of a MA project on using stories with children. It shows the importance of stories on language acquisition and concludes with some practical suggestions based on my teaching experience with young learners.

Bento Coelho da Silveira na igreja matriz de S. João Baptista

Dissertação para obtenção do Grau de Mestre em Conservação e Restauro

O romance histórico

A estrutura desta dissertação divide-se em duas partes. A primeira reside numa reflexão sobre o percurso profissional do investigador, centrada em aspectos relevantes da carreira docente no que concerne à Literatura e ao estudo da Língua. A narrativa autobiográfica produzida permitiu-nos revisitar episódios da vida profissional e as trajectórias e práticas lectivas utilizadas no ensino da poesia, do texto narrativo e dramático, e na exploração do funcionamento da língua ao longo dos anos. Recuperámos e aprofundámos conhecimentos sobre diversos autores do espaço lusófono – Trindade Coelho, Miguel Torga, Jorge Amado, Almeida Garrett, Manuel Lopes, Germano de Almeida, Érico Veríssimo, Jorge Barbosa, Sophia de Mello Breyner Andresen, Almada Negreiros, José Rodrigues Miguéis, Maria Alberta Menéres, Vergílio Ferreira, Luís de Camões, Fernando Pessoa, Gil Vicente e Padre António Vieira - e respectivas periodizações literárias, sempre que possível. Na segunda parte, procurámos reflectir com maior profundidade sobre outra temática do nosso percurso profissional, neste caso, o romance histórico. Para o efeito, necessitámos de pôr em evidência a controversa dicotomia entre modo e género literário, bem como de abordar o binómio História versus Literatura, dado que, o romance histórico, apesar de privilegiar modos de expressão ficcionais, mantem a sua ligação com a História e com a representação de valores e cenários de uma determinada época e sociedade. Tentámos contribuir para a construção de uma definição de romance histórico, distinguindo a narrativa oitocentista e a metaficção histórica pós-moderna. Terminámos o nosso trabalho discorrendo sobre Alexandre Herculano, centrando a nossa focalização nos conceitos de religiosidade, pátria e organização social no romance histórico Eurico, o Presbítero.

Legitimações dinásticas e pragmatismo. Do discurso providencialista. Fernão Lopes e António Vieira

pp. 209-219

Mapping of a Leishmania major gene/locus that confers pentamidine resistance by deletion and insertion of transposable element

Pentamidine (PEN) is an alternative compound to treat antimony-resistant leishmaniasis patients, which cellular target remains unclear. One approach to the identification of prospective targets is to identify genes able to mediate PEN resistance following overexpression. Starting from a genomic library of transfected parasites bearing a multicopy episomal cosmid vector containing wild-type Leishmania major DNA, we isolated one locus capable to render PEN resistance to wild type cells after DNA transfection. In order to map this Leishmania locus, cosmid insert was deleted by two successive sets of partial digestion with restriction enzymes, followed by transfection into wild type cells, overexpression, induction and functional tests in the presence of PEN. To determine the Leishmania gene related to PEN resistance, nucleotide sequencing experiments were done through insertion of the transposon Mariner element of Drosophila melanogaster (mosK) into the deleted insert to work as primer island. Using general molecular techniques, we described here this method that permits a quickly identification of a functional gene facilitating nucleotide sequence experiments from large DNA fragments. Followed experiments revealed the presence of a P-Glycoprotein gene in this locus which role in Leishmania metabolism has now been analyzed.

Impacto da Estimulação Vagal na Indução e Interrupção de Fibrilhação Auricular no Modelo do Coração de Coelho in Vivo

INTRODUCTION: Vagal activity is thought to influence atrial electrophysiological properties and play a role in the initiation and maintenance of atrial fibrillation (AF). In this study, we assessed the effects of acute vagal stimulation (vagus_stim) on atrial conduction times, atrial and pulmonary vein (PV) refractoriness, and vulnerability to induction of AF in the rabbit heart with intact autonomic innervation. METHODS: An open-chest epicardial approach was performed in 11 rabbits (New Zealand; 3.9-5.0 kg), anesthetized and artificially ventilated after neuromuscular blockade. A 3-lead ECG was obtained. Atrial electrograms were recorded along the atria, from right to left (four monopolar electrodes), together with a circular electrode adapted for proximal left PV assessment. Acute vagus nerve stimulation was obtained with bipolar electrodes (20 Hz). Epicardial activation was recorded in sinus rhythm, and the conduction time from right (RA) to left atrium (LA), and from RA to PVs, was measured in basal conditions and during vagus_stim. The atrial effective refractory period (ERP) and dispersion of refractoriness (Disp_A) were analyzed. Vulnerability to AF induction was assessed at the right (RAA) and left (LAA) atrial appendages and the PVs. Atrial stimulation (50 Hz) was performed alone or combined with vagus_stim. Heart rate and blood pressure were monitored. RESULTS: In basal conditions, there was a significant delay in conduction from RA to PVs, not influenced by vagus_stim, and the PV ERPs were shorter than those measured in LA and LAA, but without significant differences compared to RA and RAA. During vagus_stim, conduction times between RA and LA increased from 16+8 ms to 27+6 ms (p < 0.05) and ERPs shortened significantly in RA, LAA and LA (p < 0.05), but not in RAA. There were no significant differences in Disp_A. AF induction was reproducible in 45% of cases at 50 Hz and in 100% at 50 Hz+vagus_stim (p < 0.05). The duration of inducible AF increased from 1.0 +/- 0.2 s to 12.0 +/- 4.5 s with 50 Hz+vagus_stim (p < 0.01). AF lasted >10 s in 45.4% of rabbits during vagus_stim, and ceased after vagus_stim in 4 out of these 5 cases. In 3 animals, PV tachycardia, with fibrillatory conduction, induced with 50 Hz PV pacing during vagus_stim. CONCLUSIONS: Vagus_stim reduces interatrial conduction velocity and significantly shortens atrial ERP, contributing to the induction and duration of AF episodes in the in vivo rabbit heart. This model may be useful for the assessment of autonomic influence on the pathophysiology of AF.

Gender differences in internet usage habits: a case study in higher education

The usage of information and communication technologies has been growing among students and teachers. In order to improve the use of the Internet as a tool to support teaching and learning it is necessary to understand the Internet usage habits of students. Thus, a study was conducted with 1397 students from five schools of the Polytechnic of Porto. The data was collected through an online questionnaire abd was analized by age range, gender and scientific field. In this paper,gender differences are analyzed and presented in 3 dimensions: type of Internet usage, communication tools and the role of the Internet tools in education.

Differences in internet and LMS usage: a case study in higher education

The Internet plays an important role in higher education institutions where Learning Management Systems (LMS) occupies a main role in the eLearning realm. In this chapter we aim to characterize the Internet and LMS usage patterns and their role in the largest Portuguese Polytechnic Institute. The usage patterns were analyzed in two components: characterization of Internet usage and the role of Internet and LMS in education. Using a quantitative approach, the data analysis describes the differences between gender, age and scientific fields. The carried qualitative analysis allows a better understanding of students’ both motivations, opinions and suggestions of improvement. The outcome of this work is the presentation of the Portuguese students’ profile regarding Internet and LMS usage patterns. We expect that these results can be used to select the most suitable digital pedagogical processes and tools to be adopted regarding the learning process and most adequate LMS’s policies.

Seroprevalence of Chagas disease in schoolchildren from two municipalities of Jequitinhonha Valley, Minas Gerais, Brazil; six years following the onset of epidemiological surveillance

Six years after the beginning of the epidemiological surveillance of Chagas disease in Berilo and José Gonçalves de Minas, Jequitinhonha Valley, MG, Brazil, a serological inquiry was performed to observe whether the transmission of this endemy was occurring in this area. A randomized sample of 1,412 children seven to 14 years old, was screened. Six asymptomatic children were found to be positive, leading to 0.4% of prevalence. Hemoculture confirmed infection in five out of the six positive cases. Additional epidemiological investigation revealed important antecedents, such as disease reports in relatives and predisposing ecological and housing conditions. Our results demonstrated similar seroprevalence (0.4%) in schoolchildren, ranging from seven to 14 years old, and that were observed six years ago (0.2%) for children 0-9 year-old. Thus, considering the constant presence of Panstrogylus megistus in the peridomicile these findings emphasize the need of continuous improved epidemiological surveillance of Chagas disease in this region.

Detection of parvovirus B19 infection in formalin-fixed and paraffin-embedded placenta and fetal tissues

Parvovirus B19 infection was first discovered in 1975 and it is implicated in fetal death from hydrops fetalis the world over. Diagnosis is usually made through histological identification of the intranuclear inclusion in placenta and fetal organs. However, these cells may be scarce or uncharacteristic, making definitive diagnosis difficult. We analyzed histologically placentas and fetal organs from 34 cases of non-immune hydrops fetalis, stained with Hematoxylin and Eosin (HE) and submitted to immunohistochemistry and polymerase chain reaction (PCR). Of 34 tissue samples, two (5.9%) presented typical intranuclear inclusion in circulating normoblasts seen in Hematoxylin and Eosin stained sections, confirmed by immunohistochemistry and PCR. However, PCR of fetal organs was negative in one case in which the placenta PCR was positive. We concluded that parvovirus B19 infection frequency is similar to the literature and that immunohistochemistry was the best detection method. It is highly specific and sensitive, preserves the morphology and reveals a larger number of positive cells than does HE with the advantage of showing cytoplasmic and nuclear positivity, making it more reliable. Although PCR is more specific and sensitive in fresh or ideally fixed material it is not so in formalin-fixed paraffin-embedded tissues, frequently the only one available in such cases.

Rapid HIV diagnostic test in undocumented pregnant women applied at an inner-city teaching hospital

A significant number of Brazilian gestational-age women are still not tested for HIV, representing a high risk of transmission to their newborns. The current study sought to identify the number of pregnant women with no previous testing or undocumented for HIV referred to the Gynecology and Obstetrics Department of a Regional Teaching Hospital and included diagnosis of HIV infection determined by a rapid test and perinatal transmission in pregnancy. Medical records of all pregnant women admitted to hospital from January 2001 to December 2005 were reviewed. Pregnant women without HIV results were submitted to a rapid HIV test. Those who tested positive were further tested by ELISA and confirmed by indirect immunofluorescence assay (IIA) or Western blot (WB). The viral load from babies born to HIV-infected mothers was assessed by bDNA. Of the 16,424 pregnant women analyzed (6.6%), 1,089 were undocumented for HIV. Eleven women were positive in rapid testing and 10 were confirmed by ELISA, IIA or WB, with 0.9% seropositivity. Mother/infant pairs received zidovudine monotherapy prophylaxis and infant viral load was lower than 50 copies/mL. A higher number of pregnant women previously tested for HIV during antenatal care was verified, compared to that obtained nationwide.

Tutor Inteligente para o Ensino em Medicina

O objectivo deste trabalho consistiu no desenvolvimento de um protótipo que possibilita a adaptação do conteúdo disponibilizado de acordo com as características pessoais e psicológicas do aluno, aplicado no ensino da Medicina, nomeadamente na componente de Desenho de Estudos da disciplina de Introdução à Medicina. Para o protótipo desenvolvido foi definida uma arquitectura constituída por três componentes: um Modelo de Aluno que engloba as características pessoais e psicológicas do aluno, um Modelo de Domínio constituído por um grafo de conceitos e um Modelo Pedagógico formado pelas regras de adaptação e mecanismos de interação utilizados para obter uma solução adaptativa. Os diferentes componentes desenvolvidos para este protótipo permitem que este apresente as seguintes funcionalidades: Acesso ao conceito adequado, tendo em consideração o nível de conhecimento do aluno; Visualização de conte udos adequados ao estilo de aprendizagem do aluno; Adaptação do percurso do aluno de acordo com os resultados obtidos; Atualização das preferências de aprendizagem, com base no comportamento demonstrado pelo aluno na interação com o sistema. A primeira versão da ferramenta j a foi implementada. No entanto ainda será realizada a avaliação do protótipo em ambiente de aprendizagem, com a maior brevidade possível.