The expectations hypothesis of the term structure: some empirical evidence for Portugal

The purpose of this paper is to test the (rational) expectations hypothesis of the term structure of interest rates using Portuguese data for the interbank money market. The results obtained support only a very weak, long-run or "asymptotic" version of the hypothesis, and broadly agree with previous evidence for other countries. The empirical evidence supports the cointegration of Portuguese rates and the "puzzle" well known in the literature: although its forecasts of future short-term rates are in the correct direction, the spread between longer and shorter rates fails to forecast future longer rates. In the single equation framework, the implications of the hypothesis in terms of the predictive ability of the spread are also clearly rejected

The Expectations Hypothesis of the Term Structure: Some Empirical Evidence for Portugal

The purpose of this paper is to test the (rational) expectations hypothesis of the term structure of interest rates using Portuguese data for the interbank money market. The results obtained support only a very weak, long-run or "asymptotic" version of the hypothesis, and broadly agree with previous evidence for other countries. The empirical evidence supports the cointegration of Portuguese rates and the "puzzle" well known in the literature: although its forecasts of future short-term rates are in the correct direction, the spread between longer and shorter rates fails to forecast future longer rates. In the single equation framework, the implications of the hypothesis in terms of the predictive ability of the spread are also clearly rejected, even for the more stable period which emerged in the middle nineties.term structure of interest rates; expectations hypothesis; hypothesis testing; cointegration; Portugal

Improving VANET Protocols via Network Science

Developing routing protocols for Vehicular Ad Hoc Networks (VANETs) is a significant challenge in these large, self- organized and distributed networks. We address this challenge by studying VANETs from a network science perspective to develop solutions that act locally but influence the network performance globally. More specifically, we look at snapshots from highway and urban VANETs of different sizes and vehicle densities, and study parameters such as the node degree distribution, the clustering coefficient and the average shortest path length, in order to better understand the networks' structure and compare it to structures commonly found in large real world networks such as small-world and scale-free networks. We then show how to use this information to improve existing VANET protocols. As an illustrative example, it is shown that, by adding new mechanisms that make use of this information, the overhead of the urban vehicular broadcasting (UV-CAST) protocol can be reduced substantially with no significant performance degradation.Comment: Proceedings of the 2012 IEEE Vehicular Networking Conference (VNC), Korea, November 201

The expectations hypothesis of the term structure: some empirical evidence for Portugal

The purpose of this paper is to test the (rational) expectations hypothesis of the term structure of interest rates using Portuguese data for the interbank money market. The results obtained support only a very weak, long-run or "asymptotic" version of the hypothesis, and broadly agree with previous evidence for other countries. The empirical evidence supports the cointegration of Portuguese rates and the "puzzle" well known in the literature: although its forecasts of future short-term rates are in the correct direction, the spread between longer and shorter rates fails to forecast future longer rates. In the single equation framework, the implications of the hypothesis in terms of the predictive ability of the spread are also clearly rejected.term structure of interest rates; expectations hypothesis; hypothesis testing; cointegration; Portugal

Immigrant caregivers' adherence to Child Primary Care Health recommendations: Towards a psychosocial approach

Immigrant caregivers’ adherence to Child Primary Care (CPC) health recommendations may help minimizing health-related problems prevalent among their children (e.g. obesity, dental problems). Previous research focused on the determinants of immigrants’ access to health services, but less is known about the determinants of their adherence to health professionals’ recommendations, especially in a primary health care context. Accordingly, three main aims were outlined for this thesis: (1) investigate the psychosocial determinants of immigrant caregivers’ adherence to CPC recommendations; (2) develop and validate a measure of caregivers’ adherence to CPC recommendations; (3) explore immigrant caregivers’ social representations about the Portuguese CPC services and activities. Four studies were conducted to achieve these aims. Studies 1 and 2 were qualitative and included 35 immigrant (Cape Verdean and Brazilian) and Portuguese caregivers. Study 3 (n = 662) and Study 4 (n = 123) were quantitative cross-sectional, including immigrant (mainly Brazilian) and Portuguese parents of children aged between 2 and 6 years. Findings show that caregivers’ adherence to CPC recommendations is a two-dimensional concept – including adherence to a safe psychomotor development and nutritional counselling – reliably and validly assessed by the new CPC-Adherence Scale. Several psychosocial determinants, at different levels of analysis (structural, individual, interpersonal and intergroup), are relevant predictors of immigrant caregivers’ adherence to CPC recommendations. Caregivers’ representations of CPC and its activities to some extent differ according to caregivers' social and cultural backgrounds. These findings contribute to better understand the role of immigrants’ “non-intentional” adherence behaviors and, hence, to better inform interventions to increase CPC health professionals’ multicultural sensitivity/competence.A adesão dos cuidadores imigrantes às recomendações de Vigilância de Saúde Infantil (VSI) pode minimizar problemas de saúde prevalentes nos seus filhos (e.g. obesidade, problemas dentários). Estudos anteriores centraram-se nos determinantes de acesso dos imigrantes aos serviços de saúde, mas pouco se sabe sobre os determinantes da sua adesão às recomendações dos profissionais de saúde, especialmente num contexto preventivo de saúde. Assim, delinearam-se três objetivos principais para esta tese: (1) investigar os determinantes psicossociais da adesão dos cuidadores imigrantes às recomendações de VSI; (2) desenvolver e validar uma medida da adesão dos cuidadores às recomendações de VSI; (3) explorar as representações sociais dos cuidadores imigrantes sobre os serviços de VSI Portugueses e suas atividades. Para atingir esses objetivos, realizaram-se quatro estudos. Os Estudos 1 e 2, qualitativos, incluíram 35 cuidadoras imigrantes (Cabo-Verdianas e Brasileiras) e Portuguesas. Os Estudos 3 (n = 662) e 4 (n = 123), quantitativos e transversais, incluíram pais imigrantes (principalmente Brasileiros) e Portugueses de crianças com 2 a 6 anos de idade. Os resultados mostram que a adesão dos cuidadores às recomendações de VSI é um conceito bidimensional – inclui a adesão ao desenvolvimento psicomotor seguro e aconselhamento nutricional – medido pela desenvolvida CPC-Adherence Scale. Vários determinantes psicossociais, de diferentes níveis de análise (estrutural, individual, interpessoal e intergrupal), são preditores relevantes da adesão dos cuidadores imigrantes às recomendações de VSI. As representações sobre a VSI e suas atividades diferem, de certa forma, em função das origens sociais e culturais das cuidadoras. Estes resultados contribuem para melhorar a compreensão sobre os comportamentos de adesão “não intencionais” dos imigrantes e, consequentemente, para informar intervenções que aumentem a sensibilidade/competência multicultural dos profissionais de VSI

The role of IFNγ in higher brain function: in health and under chronic stress

Tese de Doutoramento em Ciências da SaúdeThe neuroimmunology field is at an exciting stage due to a set of revolutionary discoveries challenging the now old-fashioned dogma of the brain being “protected” from the peripheral immune system action. Immune components such as T lymphocytes and the cytokines they produce, once regarded as detrimental to the brain, are now considered integrant parts of the healthy nervous system since their regulated actions control immune surveillance but also modulate higher brain functions. The cytokine interferon-gamma (IFNγ), produced mainly by T lymphocytes, is a potent pro-inflammatory molecule, whose levels are altered in many neuropsychiatric and neurodegenerative diseases. Though studies assessing the effects of this cytokine, when administered into the brain, have shown that it affects different cellular and synaptic mechanisms underlying behavioural dimensions, it is still unclear whether this is a collateral damage of the inflammatory response or if IFNγ indeed plays a role in the modulation of non-pathological brain function. As so, we sought to explore the role of this cytokine in the modulation of brain function in physiological conditions and also after exposure to chronic stress – a paradigm known to trigger the development of psychiatric complications and also accelerate neurodegenerative processes. In the first part of the thesis (2nd Chapter) we demonstrate that, in a healthy brain, the absence of IFNγ enhances dorsal hippocampus plasticity and associated cognitive function. At the structural level, an enlargement of the dorsal hippocampus volume contrasted with the absence of alterations observed in the ventral part, highlighting that the effects of this cytokine are more selective for cognitive behaviours. Moreover, the absence of this cytokine amplifies neuroplastic phenomena in the dorsal hippocampus, namely neurogenesis, size of neuronal dendritic arborisations and presynaptic functioning, most likely contributing for the enhanced cognitive performance. On the 3rd chapter, we demonstrate that there are gender-differences on the behavioural phenotype of IFNγ KO mice, and discuss the possible association of estrogen and the IFNγ expression in the central nervous system. In the following chapter (4th Chapter) we describe the optimisation of a chronic unpredictable stress (CUS) paradigm for use in C57BL/6 mice, a strain with higher resistance to stress. This mice model of stress-related disorders exhibits, beyond the stress-related neuroendocrine and behavioural alterations, mild changes in thymic cellular populations and relevant splenic myeloid cellular alterations, with an increased number of neutrophils as the most striking change. At last (5th Chapter), we discuss the contributory role of IFNγ for the development of the immune maladaptive response to chronic stress. By submitting mice to the optimized CUS protocol, it was observed that mRNA levels of Ifnγ are elevated in the brain, specifically in the medial prefrontal and orbitofrontal cortices. Moreover, exposure to chronic stress leads to an increase of the adrenergic innervation of the spleen as to alterations on the percentage of neutrophils and monocytes/macrophages populations in the spleen. Importantly, the absence of this cytokine blunts the stress-related changes on these cell populations in the spleen. The recognition of the proinflammatory cytokine – IFNγ, as a negative regulator of hippocampal plasticity and associated cognitive function, together with its contributory role for the stress-related immune dysfunction, suggests that this cytokine may articulate the complex network that underlies the inflammatory component of neuropsychiatric disorders.A área da neuroimunologia está a atravessar uma fase excitante devido a um conjunto de descobertas revolucionárias que desafiam o seu agora antiquado dogma que visiona o cérebro como um órgão “protegido” da ação do sistema imunitário periférico. Componentes imunitários, tal como os linfócitos T e respetivas citocinas que estes produzem, outrora vistos apenas como prejudiciais para o cérebro, são agora considerados partes integrantes do sistema nervoso, uma vez que a sua ação regulada controla a vigilância imunitária mas também a modulação de funções cerebrais superiores. O interferão gama (IFNγ), uma citocina produzida principalmente por linfócitos T, é uma molécula proinflamatória cujos níveis estão alterados em diversas doenças neuropsiquiátricas e neurodegenerativas. Apesar de estudos demonstrarem que a administração desta citocina no cérebro afeta diferentes mecanismos celulares e sinápticos que estão na base de dimensões comportamentais, não é ainda claro se este efeito é um dano colateral da resposta inflamatória ou se o IFNγ tem de fato um papel na modulação da função do cérebro num contexto não patológico. Como tal, iremos aqui explorar o papel desta citocina na modulação de funções cerebrais em condições fisiológicas como também após exposição ao stress crónico – um paradigma que desencadeia o desenvolvimento de complicações psiquiátricas e acelera processos neurodegenerativos. Na primeira parte da presente tese (2º Capítulo) nós demonstramos que a ausência de IFNγ no cérebro saudável leva a uma melhoria da plasticidade do hipocampo dorsal e função cognitiva associada. Ao nível estrutural, um aumento do volume do hipocampo dorsal contrasta com a ausência de alterações volumétricas na parte ventral, sublinhando assim que esta citocina afeta seletivamente o comportamento cognitivo. A ausência desta citocina leva também a uma amplificação dos fenómenos neuroplásticos do hipocampo dorsal, nomeadamente da neurogénese, o tamanho da arborização dendrítica neuronal e o funcionamento pré-sináptico, contribuindo, muito provavelmente, para a melhoria da performance cognitiva. No 3º capítulo, nós demonstramos que existem diferenças entre géneros no fenótipo comportamental dos murganhos IFNγ KO, e discutimos a possível associação entre o estrogénio e a expressão de IFNγ no sistema nervoso central. No capítulo seguinte (4º Capítulo) descrevemos a otimização de um paradigma de stress crónico imprevisível (CUS) para murganhos C57BL/6, uma estirpe que apresenta uma maior resistência ao stress. Este modelo de murganho de disfunção associada ao stress apresenta para além das alterações neuroendócrinas e comportamentais relacionadas com o stress, alterações moderadas nas populações celulares do timo e importantes alterações celulares mielóides no baço, sendo o aumento de neutrófilos a alteração mais impressionante. Por último (5º Capítulo), discutimos o papel contributório desta citocina para o desenvolvimento da resposta imunitária maladaptativa ao stress crónico. Após expor murganhos ao protocolo otimizado de CUS foi observado um aumento nos níveis de mRNA de Ifnγ, mais especificamente nos córtices préfrontal medial e orbitofrontal. Para além disso, a exposição ao stress crónico leva a um aumento da inervação adrenérgica do baço assim como a alterações nas percentagens das populações de neutrófilos e monócitos/macrófagos no baço. A ausência de IFNγ preveniu as alterações induzidas pelo stress crónico nestas populações celulares do baço. O reconhecimento da citocina pró-inflamatória – IFNγ, como um regulador negativo da plasticidade hippocampal e função cognitiva associada, juntamente com o seu papel contributório para a disfunção imunitária associada com o stress sugere que esta citocina poderá articular a rede complexa que está na base da componente inflamatória das doenças neuropsiquiátricas.This work was funded by the European Commission (FP7): “SwitchBox” (Contract HEALTH-F2- 2010-259772) and co-financed by the Portuguese North Regional Operational Program (ON.2 – O Novo Norte) under the National Strategic Reference Framework (QREN), through the European Regional Development Fund (FEDER). Susana Isabel Gonçalves Monteiro was supported by a PhD fellowship from the Portuguese Science Foundation (FCT)/MEC with the reference SFRH/BD/69311/2010

Use of immunohistochemical techniques to investigate museum specimens of neurological disease

Mestrado em Métodos BiomolecularesOs espécimes de museu são um recurso valioso tanto para o ensino como para a investigação, mas geralmente têm sido utilizados para demonstrar a morfologia macroscópica. O objectivo da presente dissertação é determinar se modernas técnicas neuropatológicas, tal como a histologia e a imunohistoquímica, podem ser aplicadas com sucesso a espécimes de museu preservados por períodos superiores a 50 anos. Poderá ser esperado que a qualidade do material histológico recuperado de espécimes de museu seja afectada por vários factores. Estes incluem a idade do espécime, o tipo e a duração da fixação/preservação, condições do acondicionamento do espécime, informação relativa ao paciente e o período post-mortem. É importante compreender como é que os métodos de preservação mudaram com o passar dos tempos, consequentemente uma breve revisão desta história foi feita. É descrito o processo de selecção dos espécimes para este estudo e é apresentada uma investigação às características das diferentes soluções de montagem. Grande parte desta dissertação refere-se ao desenvolvimento de formas que permitam a aplicação de técnicas histológicas modernas a espécimes de museu. É demonstrado que uma pós-fixação em formaldeído 10% e um ajuste do pH da solução corante de eosina para um intervalo entre 4.8 e 5.0, são especialmente importantes em tecidos envelhecidos. Foi obtida uma coloração imunohistoquímica satisfactória utilizando o sistema EnVision+ (Dako), um polímero acoplado com HRP, com o anticorpo anti-neurofilamento (Dako). No entanto, apenas alcançou-se resultados satisfatórios com cortes de crióstato, os quais, aparentemente, produzem melhor coloração imunohistoquímica quando comparados com cortes de tecidos fixados em formaldeído e incluídos em parafina (FFPE), sugerindo assim, que o processamento em solventes orgânicos e as altas temperaturas da parafina derretida alteram a conformação do antigénio impedindo a detecção imunohistoquímica. Um estudo detalhado de três casos datados de 1953, 1954 e 1955 confirma que técnicas modernas (incluíndo imunohistoquímica) podem ser utilizadas em tecidos envelhecidos a um ponto de serem consideradas diagnosticamente válidas. Este estudo demonstra que com ajustes cuidados aos protocolos é possível obter-se notáveis resultados histológicos de alta qualidade em tecidos que foram preservados por muitos anos. Confirma também, que espécimes de museu representam um valioso recurso para ensino e para a investigação a um nível ultraestrutural. ABSTRACT: Museum Specimens are a valuable resource both for teaching and research but have generally been used to show the gross morphology. The aim of this dissertation is to determine if modern neuropathological techniques, such as histology and immunohistochemistry, can be applied successfully in museum specimens that have been preserved for periods in excess of 50 years. It may be expected that many factors could affect the quality of histological material retrieved from museum specimens. These include the age of the specimen, type and length of fixation/preservation, storage conditions, patient information and post-mortem period. It is important to understand how preservation methods had changed over time, and therefore, the complex history of “potting” is reviewed. The process of selecting specimens for this study is described and an investigation into the characteristics of mounting solutions is presented. The major part of the dissertation concerns the development of ways in which to apply modern histological techniques to museum specimens. It is shown that post-fixation in formaldehyde 10% and an adjustment of the eosin stain solution to a pH ranging between 4.8 and 5.0 are especially important in older tissues. Satisfactory immunohistochemistry staining was obtained using EnVision + (Dako) system, a HRP labeled polymer, with anti-neurofilament antibody (Dako). Nevertheless, successful results were only achieved with cryostat sections, as they appeared to produce better immunohistochemistry staining when compared to formalin-fixed paraffin-embedded (FFPE) sections, suggesting that processing in organic solvents and high temperatures of molten paraffin alters the conformation of the antigen hampering immunohistochemistry detection. A detailed study of three cases from 1953, 1954 and 1955 confirms that modern techniques (including immunohistochemistry) can be used in aged tissue to the point where they are useful diagnostically. This study shows that with careful adjustment to protocols it is possible to achieve remarkably high quality histological results in tissues that have been preserved for many years. It confirms that specimens in museums represent a valuable resource for teaching and research at an ultrastructural level

Short and long run tests of the expectations hypothesis: the Portuguese case

The purpose of this paper is to test both short- and long-run implications of the (rational) expectations hypothesis of the term structure of interest rates using Portuguese data for the interbank money market. The results support only a very weak, long-run or "asymptotic" version of the hypothesis, and broadly agree with previous (but separate) evidence for other countries. Empirical evidence supports the cointegration of Portuguese rates and the "puzzle" well known in the literature: although its forecasts of future short-term rates are in the correct direction, the spread between longer and shorter rates fails to forecast future longer rates. Further short-run implications of the hypothesis in terms of the predictive ability of the spread are also clearly rejected, even for the more stable period which emerged in the middle nineties.Term structure; Expectations hypothesis; Hypothesis testing; Structural breaks; Portugal

Insights on consumer online purchase decisions of women’s footwear

Shoes are probably one of the most difficult products to sell online due to the high need-for-touch (NFT) displayed: people need to experiment the product before buying it, more than in any other item. On another hand, women are more prone than men to buy fashion and apparel products through the web channel. This paper investigates the factors driving women consumers to shop footwear products online. A qualitative research method was used grounded on semistructured, in-depth interviews that were conducted to corroborate the constructs defined in the proposed conceptual model namely: convenience, recreation, NFT and social e-shopping. The interviews were focused on the demand side to understand the female consumers’ perspective and on the top managers of women’s shoes companies representing the suppliers’ viewpoint. The results show that women highly appreciate the convenience that shopping shoes online provides as well as its recreational nature. The NFT also stands out in the shoe market context mainly due to the particularities related to shoe size. Additionally, social e-shopping was found not be as important for women as anticipated as they see social networks more as a communication platform for brands, and less as a factor that influences their predisposition to shop shoes online. On the suppliers’ side, the interviews revealed that managers believe in bloggers and social media influence and its consideration as part of the overall marketing strategy.info:eu-repo/semantics/publishedVersio