2,100 research outputs found
The origins of monetary policy disagreement: The role of supply and demand shocks
We investigate how dissent in the FOMC is affected by structural macroeconomic shocks
obtained using a medium-scale DSGE model. We find that dissent is less (more) frequent when
demand (supply) shocks are the predominant source of inflation fluctuations. In addition, supply
shocks are found to raise private sector forecasting uncertainty about the path of interest rates.
Since supply shocks impose a trade-off between inflation and output stabilization while demand
shocks do not, our findings are consistent with heterogeneous preferences over the dual mandate
among FOMC members as a driver of policy disagreement.info:eu-repo/semantics/acceptedVersio
Visualização de dados arqueológicos: Um exemplo de utilização do visualization toolkit
A Arqueologia tem como principal objectivo reconstruir todo o processo que conduziu à formação do registo
arqueológico. Ou seja, pretende-se compreender como foram erguidos edifícios e estruturas, e como foram
destruídos e cobertos por sucessivas camadas de terra. Entender os mecanismos de formação de um arqueosítio
é fundamental para a sua interpretação. Modelos 3D de reconstituição de edifícios são uma importante ferramenta
para assistir o arqueólogo nesta tarefa.
Com este trabalho pretende-se mostrar que a aplicação de técnicas actuais de Visualização a dados arqueológicos
é uma mais-valia importante na prossecução desses objectivos. Para isso desenvolveu-se um primeiro
protótipo de aplicação, com base no VTK, que importa dados arqueológicos e modelos reconstruídos, e permite
a sua visualização interactiva. É possível realizar um conjunto de operações sobre os modelos visualizados,
com o objectivo de proporcionar aos arqueólogos diferentes tipos de leitura de um arqueosítio
A mass spectrometry study of compounds with environmental and biological interest
Tese de doutoramento, Química (Química Analítica), Universidade de Lisboa, Faculdade de Ciências, 2010The leading thread of this work is the application of Mass
Spectrometry to the study of environmental and biological relevant
compounds. Several studies were performed involving the development
and optimization of efficient analysis methodologies, the behaviour of
the compounds under study was investigated using various mass
spectrometry techniques and fundamental studies were carried out, most
of them complemented with semi-empirical calculations.
Matrix-Assisted Laser Desorption/Ionization (MALDI) has been
extensively used for the analysis of large molecules. Nevertheless, since
the technique provides soft and efficient ionization of thermolabile and
non-volatile organic compounds, we decided to investigate its
application to small molecules as an alternative ionization method. For
that we compared the performance of nanosized TiO2 anatase as matrix
with that of common organic matrices. The formation of organic
matrix-flavonoid cluster ions was also investigated and it was found to
be dependent of the structure of the flavonoid.
Aniline derivatives are of great industrial importance and several
constitute a significant group of pollutants. The gas-phase behaviour of
halo- and nitroanilines under electrospray ionization mass spectrometry
conditions was studied. Isomer identification methodologies are
proposed using for that purpose competitive fragmentations of protonbound
heterodimers. Preliminary results on the behaviour of the aniline
derivatives when subjected to electron capture dissociation conditions
are presented and discussed. The behaviour of five isoflavones was studied under electrospray
ionization mass spectrometry in the positive ion mode. The
fragmentation mechanisms were proposed taking into account MSn
experiments, accurate mass measurements and semi-empirical
calculations. Some of the fragmentations were found to be dependent
on the substitution pattern of the B-ring and the ions afforded by these
fragmentations can be considered as diagnostic ions.
Several newly synthesized -lactones, fused or C-C linked to sugar
rings, were studied. Their fragmentation mechanisms were proposed
taking into account MSn experiments and semi-empirical calculations. FTICR-MS; ESI; MALDI; Fragmentation Mechanisms; Collision Induced DissociationEste trabalho tem como domínio comum a aplicação da
Espectrometria de Massa ao estudo de vários compostos com interesse
ambiental e biológico. Foram realizados estudos que envolvem o
desenvolvimento e optimização de metodologias eficientes de análise;
foi investigado o comportamento dos compostos em estudo usando
várias técnicas de espectrometria de massa e foram realizados estudos de
natureza fundamental, a maioria dos quais complementados por cálculos
semi-empíricos. Concretamente:
Ionização/desorção laser assistida por matriz (MALDI) é uma
técnica de ionização muito usada na análise de moléculas com massas
moleculares elevadas. No entanto, a sua capacidade de ionizar de um
modo suave e eficiente compostos não voláteis e termicamente instáveis
levou-nos a investigar a sua aplicabilidade à análise de moléculas
pequenas. Para tal, comparou-se a performance da fase anatase do TiO2
com a de matrizes orgânicas convencionais na ionização de vários
compostos cobrindo várias classes. Um dos compostos em particular,
um flavonóide, formou iões agregados com a matriz orgânica, o que nos
levou a aprofundar o estudo deste comportamento. Conclui-se que a
estrutura do flavonóide influencia a formação dos iões agregados.
Derivados de anilina têm uma grande importância a nível
industrial e os derivados halogenados, em particular, constituem um
grupo de poluentes bastante significativo. Assim, estudou-se o
comportamento em fase gasosa de halo- e nitroanilinas com o intuito de
estabelecer mecanismos de fragmentação e metodologias que permitam
a identificação de isómeros. Para a identificação de isómeros recorreu-se a fragmentações competitivas de heterodímeros ligados por protão.
Também são apresentados e discutidos resultados preliminares sobre o
comportamento de derivados de anilina quando expostos a condições
de dissociação por captura de electrões.
O comportamento de cinco isoflavonas foi estudado no modo
positivo e recorrendo à espectrometria de massa com ionização por
electrospray. Foram propostos mecanismos de fragmentação tendo em
conta experiências de espectrometria de massa tandem, medições de
massa exacta e cálculos semi-empíricos. Algumas das fragmentações
observadas são dependentes do anel B e dos seus substituintes e, como
tal, os iões originados por estas fragmentações podem ser considerados
como iões diagnóstico.
Várias -lactonas fundidas ou ligadas a açúcares, compostos
recentemente sintetizados, foram estudadas com o intuito de estabelecer
mecanismos de fragmentação. Tal foi feito tendo em conta dados de
espectrometria de massa tandem e cálculos semi-empíricos. FTICR-MS; ESI; MALDI; Mecanismos de Fragmentação; Dissociação Induzida por ColisãoThe work presented in this thesis was performed in the
Environmental and Biological Mass Spectrometry Group,
Departamento de Química e Bioquímica da Faculdade de
Ciências da Universidade de Lisboa, with the financial
support of Fundação para a Ciência e a Tecnologia
(SFRH/BD/27614/2006
Public policies for the promotion of horticulture: the case of Algarve´s citrus.
Special session 27: "Territorial Governance, Rural Areas and Local Agro Food Systems"(964)This research approaches some factors that have been affecting the competitiveness faced by the Algarve’s citrus culture since the European Single Market came into force and before a more and more global economy.
As it is already known, in a global economy any competitive strategy must have underlying quality(ies). These are understood as the capacity to satisfy the market considered as a whole of the main types of agents at the different levels of Algarve’s citrus system. So, the main object of this work is to identify eventual (technical and institutional) mal-functions concerning the Algarve citrus system, that can fail either directly or indirectly to meet the principal clients/consumers’ expectations.
The study took into account the general context where the Algarve’s citrus culture is inserted. The aim is to identify the constraints faced by the sector in order to understand the main clients, suppliers and competitors’ behaviours.
The results have allowed us to characterize the quality attributes considered as determinants when the citrus fruits are acquired, namely the Algarve’s citrus, by the national consumers as well as by the main distribution channels, in case they are presented in the market as differentiated or undifferentiated.
The facts identified in the empirical research indicate that limitations of technical and institutional order can make unfeasible or strongly condition the capacity of the Algarve citrus culture (production subsystem) to meet the market requirements.
The conclusions reached for the development of the Algarve citrus culture, were based on Hayami and Ruttan´s “induced technical and institutional innovation” theory (1998). We think we have given a contribution towards the definition of strategies for the Algarve’s citrus culture development, bearing in mind both the market and the available resources.This paper has been partially supported by the Portuguese Foundation for Science and Technology (FCT
Visualização e análise de dados arqueológicos usando o visualization toolkit
Os modelos virtuais são cada vez mais utilizados quer na divulgação de sítios arqueológicos, quer como ferramentas
auxiliares do trabalho de investigação dos arqueólogos. Para tal, modelos 3D construídos com base
numa interpretação dos dados arqueológicos, ou numa leitura de planos de escavação, podem ser entendidos
como maquetas digitais virtuais, que podem ser “desmontadas” para melhor analisar e compreender uma
reconstrução de estruturas arquitectónicas encontradas numa escavação, ou a visualização da distribuição
espacial dos achados.
Este artigo apresenta um segundo protótipo de uma aplicação que disponibiliza um conjunto de funcionalidades
adequadas à análise arqueológica e que actuam sobre modelos virtuais 3D. À semelhança do anterior,
este protótipo foi desenvolvido com base no VTK e permite atingir os objectivos definidos: (1) utilização de
modelos 3D como ferramentas auxiliares do trabalho de investigação arqueológica e (2) reconstrução de
sequências de planos de escavação. As novas leituras, decorrentes da combinação arbitrária de operações de
rotação, translação, ampliação/redução, “desmontagem” e seccionamento de modelos 3D, permitem aos utilizadores
do sistema compreender melhor os sítios arqueológicos em estudo.Zacon Grou
Understanding memorable enogastronomic experiences: A qualitative approach
The objectives of this chapter are to:
- Introduce those factors that make a memorable enogastronomic experience for tourists visiting a destination;
- Present qualitative findings that reveal that gastronomy and wines play a major role in the way that visitors experience a destination and indicate that some travellers would return to the same destination to savour its unique gastronomy.info:eu-repo/semantics/acceptedVersio
Horticulture in Algarve: a case study for sustainable development
This study takes into account the general context where the Algarve’s citrus culture is inserted. The aim is to identify the constraints faced by the sector in order to understand the main clients, suppliers and competitors’ behaviours.
The results have allowed us to characterize the quality attributes considered as determinants when the citrus fruits are acquired, namely the Algarve’s citrus, by the national consumers as well as by the main distribution channels, in case they are presented in the market as differentiated or undifferentiated.
The facts identified in the empirical research indicate that limitations of technical and institutional order can make unfeasible or strongly condition the capacity of the Algarve citrus culture (production subsystem) to meet the market requirements.
The conclusions reached for the development of the Algarve citrus culture, were based on Hayami and Ruttan´s “induced technical and institutional innovation” theory (1998). We think we have given a contribution towards the definition of strategies for the Algarve’s citrus culture development, bearing in mind both the market and the available resources
Lipid composition and dynamics of cell membranes of Bacillus stearothermophilus adapted to amiodarone
Bacillus stearothermophilus, a useful model to evaluate membrane interactions of lipophilic drugs, adapts to the presence of amiodarone in the growth medium. Drug concentrations in the range of 1-2 [mu]M depress growth and 3 [mu]M completely suppresses growth. Adaptation to the presence of amiodarone is reflected in lipid composition changes either in the phospholipid classes or in the acyl chain moieties. Significant changes are observed at 2 [mu]M and expressed by a decrease of phosphatidylethanolamine (relative decrease of 23.3%) and phosphatidylglycerol (17.9%) and by the increase of phosphoglycolipid (162%). The changes in phospholipid acyl chains are expressed by a decrease of straight-chain saturated fatty acids (relative decrease of 12.2%) and anteiso-acids (22%) with a parallel increase of the iso-acids (9.8%). Consequently, the ratio straight-chain/branched iso-chain fatty acids decreases from 0.38 (control cultures) to 0.30 (cultures adapted to 2 [mu]M amiodarone). The physical consequences of the lipid composition changes induced by the drug were studied by fluorescence polarization of diphenylhexatriene and diphenylhexatriene-propionic acid, and by differential scanning calorimetry. The thermotropic profiles of polar lipid dispersions of amiodarone-adapted cells are more similar to control cultures (without amiodarone) than those resulting from a direct interaction of the drug with lipids, i.e., when amiodarone was added directly to liposome suspensions. It is suggested that lipid composition changes promoted by amiodarone occur as adaptations to drug tolerance, providing the membrane with physico-chemical properties compatible with membrane function, counteracting the effects of the drug.http://www.sciencedirect.com/science/article/B6VNN-419BF60-K/1/8f2d4fae7f9c131d26230cf4123da94
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