The cost channel reconsidered: a comment using an identification-robust approach

We re-examine the empirical relevance of the cost channel of monetary policy (e.g. Ravenna and Walsh, 2006), employing recently developed moment-conditions inference methods, including identification-robust procedures. Using US data, our results suggest that the cost channel effect is poorly identified and we are thus unable to corroborate the previous results in the literature.Cost channel; Phillips curve; GMM; Generalized Empirical Likelihood; Weak Identification.

The Properties of Cointegration Tests in Models with Structural Change

In this paper we examine, by means of Monte Carlo simulation, the properties of several cointegration tests when long run parameters are subject to structural changes. We allow for different types of stochastic and deterministic regime shifts, more specifically, changes governed by Markov chains, martingale parameter variation, sudden multiple breaks and gradual changes. Our Monte Carlo analysis reveals that tests with cointegration as the null hypothesis perform badly, while tests with the null of no cointegration retain much of their usefulness in this context.Structural change; Cointegration; Tests; Monte Carlo

The Forecast Performance of Long Memory and Markov Switching Models

Recent research has focused on the links between long memory and structural change, stressing the long memory properties that may arise in models with parameter changes. In this paper, we contribute to this research by comparing the forecasting abilities of long memory and Markov switching models. Two approaches are employed: a Monte Carlo study and an empirical comparison, using the quarterly Consumer Price inflation rate in Portugal in the period 1968-1998. Although long memory models may capture some in-sample features of the data, when shifts occur in the series considered, their forecast performance is relatively poor, when compared with simple linear and Markov switching models. Moreover, our findings, in a more general framework, are in accordance with the works of Clements and Hendry (1998) and Clements and Krolzig (1998), reinforcing the idea that simple linear time series models remain useful tools for prediction.Long Memory; Structural change; Forecasting

Robust Estimates of the New Keynesian Phillips Curve

In this paper, we examine the hybrid specification of the New Keynesian Phillips Curve (NKPC) proposed by Gali and Gertler (1999) by employing recently developed momentconditions inference procedures. These methods provide a more efficient and reliable econometric framework for the analysis of the NKPC. In particular, we address the issue of parameter identification, providing robust estimates and confidence sets for the model’s parameters. Our results show that the NKPC remains a valid and reliable empirical tool to explain inflation dynamics.price regulation, commitment problem, ratchet effect, under-investment

Moment conditions model averaging with an application to a forward-looking monetary policy reaction function

In this paper, we examine the empirical validity of the baseline version of the forward-looking monetary policy reaction function proposed by Clarida, Gali, and Gertler (2000). For that purpose, we propose a moment conditions model averaging estimator in the Generalized Method of Moments and Generalized Empirical Likelihood setups. We derive some of their asymptotic properties under correctly specified and misspecified models. Although the model averaging estimates and the standard procedures point to a stabilizing policy rule during the Paul Volcker and Alan Greenspan tenures but not so during the pre-Volker period, our results cast serious doubts on the significance of the cyclical output variable as a forcing variable in the FED funds dynamics during the Volcker-Greenspan period.

Deteção molecular de Mycobacterium avium subsp. paratuberculosis em raposas-vermelhas (Vulpes vulpes)

Deteção molecular de Mycobacterium avium subsp. paratuberculosis em raposas-vermelhas (Vulpes vulpes)

O Evento FCNC 2005 e o Turismo

Este relatório foi elaborado com base num estudo que decorreu entre Julho e Dezembro de 2005. O objectivo geral do projecto que se desenvolveu traduziu-se na tentativa de aprofundar o conhecimento sobre o perfil dos visitantes não residentes no Algarve que participaram nos eventos culturais da Faro, Capital Nacional da Cultura, assim como as suas motivações, actividades e impressões. Além deste objectivo o Centro de Estudos da Escola Superior de Gestão Hotelaria e Turismo (ESGHT) da Universidade do Algarve tinha em mente a prossecução de outros fins que se prendiam com a criação de uma linha de investigação nos domínios do Património, da Cultura e do Turismo dado que possui um conjunto de docentes com formação especializada nesta área. Acresce que esta instituição é membro da ATLAS - Association for Tourism and Leisure Studies agremiação que desenvolve, com regularidade, estudos sobre o Perfil do Turista Cultural, a nível mundial, em parceria com estabelecimentos de ensino superior, nos quais nós temos vindo a participar com a colaboração de algumas câmaras municipais do Algarve. Para concretizar os objectivos propostos, foi realizada, numa primeira fase, recolha de informação relativa a estudos desenvolvidos no âmbito de eventos anteriores, nomeadamente: Cidades e Capitais Europeias da Cultura; Porto, Capital Europeia da Cultura; Coimbra, Capital Nacional da Cultura; entre outros. A investigação primária teve por base principal um inquérito aplicado junto de uma amostra de visitantes/turistas participantes na programação de Faro Capital Nacional da Cultura, tendo-se previsto uma amostragem mínima de 500 inquéritos a visitantes de várias nacionalidades. Estes inquéritos foram administrados por dois estagiários recrutados entre os alunos finalistas da ESGHT. O inquérito que se aplicou teve por base o já produzido pela ATLAS (Association for Tourism and Leisure Education) para estudar eventos associados ao turismo e estava disponível em quatro idiomas: português, inglês, alemão e espanhol. Na amostragem desenvolvida tentou-se aplicar os questionários em diferentes tipos de eventos, para que a amostra fosse representativa (ver capítulo 6) das várias actividades programadas: exposições; eventos de rua (concertos, festivais); eventos em recinto fechado (teatro, dança, concerto); atracções (museus, monumentos). No final da investigação teve lugar uma apresentação pública dos resultados a que se seguiu a elaboração do relatório que se passa a apresentar. Este é constituído por sete capítulos sendo que no primeiro se estabelece a relação entre turismo e cultura, no segundo sumaria-se a evolução do turismo cultural na Europa e traça- se o perfil do turista cultural, no terceiro expõe-se a ligação entre turismo e eventos, (com maior relevo para os eventos culturais), no quarto descreve-se o conceito de cidade e de capital europeia da cultura, no quinto caracteriza-se a Faro capital da Cultura, no sexto explica-se a metodologia seguida, e por fim, no sétimo apresentam-se os resultados obtidos e tecem-se as considerações finais

A PV/T and Heat Pump based trigeneration system model for residential applications

A solar trigeneration system, based on photovoltaic-thermal (PV/T) collectors, photovoltaic (PV) modules and a heat pump unit for heating and cooling, is modelled to forecast the thermal and electric yields of the system. The aim of the trigeneration system is to provide enough electricity, domestic hot water (DHW), heating and cooling power to meet the typical demand of an urban single family dwelling with limited roof area and allow the household to achieve a positive net energy status. The PV/T collectors and PV modules provide the electricity while the former also powers the DHW component of the trigeneration system. The heating and cooling components rely on a vapour compression cycle heat pump unit powered by electricity. In Fong et al. (2010), solar-powered electric compression refrigeration was found to have the most energy saving potential in subtropical climates. Thus, a heat pump based cooling system is a cost effective solution for residential applications in Lisbon,Portugal. Thus, according to the dwelling's location, construction details and energy demand patterns, the model computes the system's net results by comparing the dwelling demand with the trigeneration system supply. The paper presents a breakdown of the proposed trigeneration system model and describes each component briefly. Preliminary results produced by the model are presented and analysed in order to identify possible ways of improving the overall system performance

Alkane coiling in perfluoroalkane solutions: a new primitive solvophobic effect

In this work, we demonstrate that n-alkanes coil when mixed with perfluoroalkanes, changing their conformational equilibria to more globular states, with a higher number of gauche conformations. The new coiling effect is here observed in fluids governed exclusively by dispersion interactions, contrary to other examples in which hydrogen bonding and polarity play important roles. FTIR spectra of liquid mixtures of n-hexane and perfluorohexane unambiguously reveal that the population of n-hexane molecules in all-trans conformation reduces from 32% in the pure n-alkane to practically zero. The spectra of peffluorohexane remain unchanged, suggesting nanosegregatiori of the hydrogenated and fluorinated chains. Molecular dynamics simulatiOns support this analysis. The new solvophobic effect is prone to have a major impact on the structure, organization, and therefore thermodynamic properties and phase equilibria of, fluids involving mixed hydrogenated and fluorinated chains.Fundacao para a Ciencia e Tecnologia [UID/NAN/50024/2013, UID/QUI/0100/2013, SFRH/BPD/81748/2011