1,018 research outputs found
Teaching Transmission Line Propagation and Plane Wave Reflection Using Software Tools
Teaching transmission lines and wave propagation is a challenging task because it involves quantities not easily observable and also because the underlying mathematical equations—functions of time, distance and using complex numbers—are not prone to an easy physical interpretation in a frequent framework of a superposition of traveling waves in distinct directions. In such a context, tools with a strong visualization and easy student interaction can improve the learning outputs. We describe here a few tools and give basic exercises to address the main learning topics
Genetic and ecological consequences of a shifted phenology in a forest defoliator
Doutoramento em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de AgronomiaThaumetopoea pityocampa is a major pine defoliatior over the Mediterranean Basin. An atypical population with a shifted phenology, ongoing an allochronic differentiation process, was recently discovered in Mata Nacional Leiria, Portugal. The shifted population reproduces in spring achieving its larval development during summer (SP), whereas the sympatric typical population reproduces in summer and has winter larval development (WP). They are reproductively isolated through time, although sharing the same space and host species. General objectives of this work were to characterize the current and potential distribution range of this population, its spatial/temporal genetic and demographic patterns, and ecological adaptations.
Field monitoring of presence/absence of SP nests throughout Leiria showed that it is expanding to North and South. Current distribution is restricted to coastal areas, along ca. 120 x 20 km area. Distribution models predict that its distribution will be restricted to coastal areas, due to unsuitable climate inland, being the maximal temperatures of the summer months the main constraint.
A phylogeographic study confirmed high SP differentiation from other Portuguese populations. A spatio-temporal sampling along two geographic transects in Leiria zone revealed high stability in time of the genetic composition and structure. A striking demographic result showed that SP tends to apparently displace the WP from the coastal zones suggesting a possible competition phenomenon. Gene flow between the two populations was shown to remain low, even if some SP males actually emerge late.
Ecological differentiation was assessed at egg and larval stages. The effect of a wide range of high temperatures on egg survival and development showed higher performances of the SP. Furthermore, SP larvae showed a better ability to cope with host plant water stress, evidencing adaptation to summer feeding activity. This study highlights intra-specific variations on the response of this insect to environmental constraints evidencing ecological adaptation following allochronic differentiationN/
Introduction: Transcultural spaces and identities in Iberian studies
This volume brings together innovative research across the diverse field of Iberian Studies, including insights from economics, society, politics, literature, cinema and other art forms, either in a revisionist perspective or incorporating new data. Reflecting recent developments in the field, the subject matter extends beyond the boundaries of Spain and Portugal, as it also includes transnational and transatlantic interconnections with Europe, Africa and the Americas and its scope ranges from the nineteenth century to the effects of the Catalan independence crisis and Brexit. The 18 chapters here are authored by established academics and early career researchers from the UK, Italy, France, Germany, Spain, Portugal, Argentina, Brazil, Japan and the USA. The book will appeal to students, researchers and all who have a particular interest in deepening their understanding of the countries of the Iberian Peninsula
Interplay between Erythrocyte Peroxidases and Membrane
Red blood cells (RBCs) are continuously exposed to oxidative stress (OS), mainly due to their primary function as oxygen carriers. Since RBC is a unique cell, without nucleus or other organelles, it presents a very special metabolism and a highly efficient antioxidant system to face OS conditions. Hemoglobin and RBC membrane are the major targets of oxidative modifications when RBC antioxidant capacity is overwhelmed. Fortunately, non-enzymatic agents, such as glutathione, and enzymatic agents, namely, several peroxidases, such as catalase, glutathione peroxidase and peroxiredoxin 2, are able to prevent OS damage. Although these peroxidases are mainly cytosolic enzymes, evidence exists about their association to the RBC membrane. So far, it appears that the relative importance of the three enzymes is related to hydrogen peroxide levels within the RBC. In this chapter, we will focus on the importance of these peroxidases in the RBC’s defense against OS mainly in the RBC cytosol and also the interplay between them and the RBC membrane. The potential role of their binding to the membrane will also be addressed
Gastronomy and Wines in the Alentejo Portuguese Region: Motivation and Satisfaction of Tourists from Évora
Abstract: Food and winemaking are a recognized tangible and intangible cultural
heritage of Portugal. From the relationship between these two components, a strategic
product emerged with a considerable potential for tourism industry, which is not
ignored by many of tourism organizations. This chapter intends to analyze food and
winemaking from a tourism demand perspective. Particularly, this study describes
visitors’ profile, including, their motivations, their knowledge about the enological
and gastronomic resources and the degree of satisfaction. A total of 308
questionnaires were collected between February and May of 2012, from the visitors
that visited the historic center of Évora (Alentejo-Portugal). Results reveal a visitor
profile associated with regional cuisine and wine products from Portugal. Moreover,
visitors’ evidenced a high level of knowledge regarding the Portuguese cuisine and
regional wines; although this not matches with their primary motivation for visit the
city of Évora.
R. Amara
Perceções da Motivação e da Satisfação para uma melhor qualidade no Trabalho: O caso do Hotel Convento do Espinheiro
Diversos autores (Day e Peters, 1994; Evans e Lindsay, 2002) têm-se confrontado
com o conceito de qualidade nos serviços, como um meio que tende a divulgar a
eficácia e eficiência dos mesmos. A noção de qualidade denota, atualmente, uma
estratégia de competitividade e um agente para o desenvolvimento sustentado, de
modo a responder às expetativas dos consumidores. No setor turístico, esse
desenvolvimento ambiciona-se que seja em harmonia com um turismo melhor e
de mais qualidade (Cândido, 2005).
O objetivo do presente trabalho consiste em avaliar a qualidade de uma
organização do setor turístico na região do Alentejo (Évora), do ponto de vista dos
colaboradores internos e superiores hierárquicos, através da aplicação de um
inquérito por questionário, com vista à obtenção de melhorias contínuas em todas
as áreas organizacionais.
A importância que a satisfação e a motivação têm no ambiente de trabalho faz
com que todas as práticas de gestão formem uma estrutura coerente, que é
aperfeiçoada constantemente, e que sustenta o desempenho da estratégia
pretendida para a organização
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