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Modelling tourism demand is essential when tourism policymakers plan tourism activities. The tourism industry is extremely susceptible to specific events’ effects, so good models must be found that reflect volatility. This study sought to review systematically the recent literature on this topic, specifically targeting models used to analyse tourism demand. The literature reveals some determinants of volatility in the tourism industry, such as income, gross domestic product and exchange rate, as well as crime, major events, big shocks, epidemics, weather conditions and the absence or existence of direct flights. Moreover, the review showed that modelling volatility is an emergent approach used in the analysis of tourism demand time series. This study’s results reveal pathways for the use of volatility models in tourism demand studies, which will allow managers and decision makers to adapt policies to deal with the volatility associated with tourism. info:eu-repo/semantics/publishedVersion

Customer churn has been stated as one of the main reasons of profitability losses in the telecommunications industry. As such, it seems critical to have an a priori knowledge about the risk of a given customer to churn at any moment, in order to take preventive measures to avoid the defection of potentially profitable customers. This study intends to develop a duration model of the residential customer churn in this industry in Portugal. We found empirical evidence that the variables that influence customer churn are the total number of overdue bills since ever, average monthly spending, average value of additional internet traffic, payment method, equipment renting, and the subscription of a flat plan. We also found that the probability of a customer to churn is neither constant over time nor across customers. info:eu-repo/semantics/publishedVersion

This paper examines the behavior of several implied volatility indexes in order to compare them with the volatility forecasts obtained from estimating a GARCH model. Though volatility has always been a prevailing subject of research it has become particularly relevant given the increasingly complexity and uncertainty of stock markets in these days. An important measure to assess the market expectations of the future volatility of the underlying asset is the implied volatility (IV) indexes. Generally, these indexes are calculated based on the prices of out-of-the money put and call options on the underlying asset. Sometimes called the “investor fear gauge”, the IV indexes are a measure of the implied volatility of the underlying index. This study focuses on the implied and GARCH forecasted volatility of some emerging countries and some developed countries. More specifically, it compares the predictive power of the IV indexes with the ones provided by standard volatility models such as the ARCH/GARCH (Autoregressive Conditional Heteroskedasticity Model/ Generalized Autoregressive Conditional Heteroskedasticity Model) type models. Finally, a debate of the results is also provided.

Este texto pretende dar a conhecer o conjunto de gravuras rupestres da Bouça da Cova da Moura. A análise efetuada ao conjunto de signos permitiu denotar, a presença de composições gráficas pertencentes à tradição artística que se convencionou denominar de arte atlântica, representações de cariz mais esquemático e motivos de época histórica. Na envolvência dos afloramentos gravados descobriram-se monumentos megalíticos, áreas de dispersão de materiais cerâmicos datáveis do Calcolítico, uma ocupação da Idade do Bronze, além de materiais dispersos deste período genérico, relevantes para a análise da biografia deste lugar numa pequena escala de análise. A inserção deste locus numa escala mais ampla de análise, ou seja, os Montes do Leandro, pequeno contraforte da serra do Bougado, permite admitir que este complexo de gravuras rupestres faria parte de um vasto território de ampla significação simbólica durante a Pré-história Recente. Neste sentido as diferentes materialidades seriam, resultado de um processo aditivo que resulta da frequência do planalto, da sua da reutilização e reinterpretação, num templo cíclico., The aim of this paper is to offer an overview of the rock art assemblage at Bouça da Cova da Moura in its local and regional contexts. The site is located in Ardegães, parish of Águas Santas, municipality of Maia, district of Porto, in north-western Portugal. Fieldwork carried out in the end of the 20th century and the beginning of the 21st century, resulted in the discovery of new carved surfaces in the place where the well-known ‘pedra partida de Ardegães’ had been found; it was not only possible to unveil aspects related to its topographical context but also to discover other materialities which are spatially related to the rock carvings. Stylistic analysis undertaken to the set of carvings allow us to consider that we are beyond an assemblage which is partly constituted of rock art compositions belonging to the prehistoric art tradition conventionally called atlantic art, there is one schematic human figure and other motifs that belong to historical periods. In the vicinities of the carved outcrops there are megalithic monuments dated to the Neolithic, scatters of pottery fragments probably dated to the Copper Age, evidence for a Bronze Age occupation site, as well as clusters of surface finds from the same period. Overall, the field data recovered so far is extremely relevant for the analysis of the biography of this place at a small scale of analysis. The integration of this locus in a wider spatial scale, i.e. in the plateau that cuts across the territory in the north-south direction linking it to the Bougado hills, allow us to admit that this rock art complex would be part of a vast territory of symbolic significance in Late Prehistory. Thus, the distinct archaeological remains may be the materialisation of the importance of this geomorphological unit in the cognitive map and ideological universe of the prehistoric communities who dwelled, over a long period of time, along the middle basin of the River Neiva. These different materialities would result from a process of addition in the occupation of the plateau, of its reuse and reinterpretation in a cyclical time., Este texto insere-se no projeto Bronze Age Landscapes in the west of Iberian Peninsula / Paisagens da Idade do Bronze no ocidente peninsular (SFRH/BSAB/ 986/10) apoiado e financiado pela FCT no âmbito de uma Bolsa de Licença Sabática., info:eu-repo/semantics/publishedVersion

Bouça da Cova da Moura is the local place-name attributed to a stretch of a plateau overlooking the Leça valley. Here, Neolithic burial mounds share their landscape setting with scatters of archaeological materials that include Bell Beaker fragments, idols and metalwork. Since these are mostly surface findings, their contexts have not yet been accurately determined. Another significant feature is the presence of prehistoric rock carvings. The plateau may thus be considered a public space, conceptually and physically built over time. Its significance and meanings were certainly created and transmitted through practices of memory construction which are representative of cultural identity and social cohesion., Le site de Bouça da Cova da Moura se trouve sur un plateau faisant face au Rio Leça. On y a identifié des tertres funéraires du Néolithique, auxquels sont associés des zones de concentration d’artefacts, incluant céramiques campaniformes, idoles et mobilier métallique. S’agissant de mobilier de surface, le contexte de ces différentes concentrations n’a pas été déterminé avec attention. Un autre fait significatif est l’apparition de gravures rupestres préhistoriques. On peut considérer le plateau comme un espace publique, qui s’est bâti physiquement et conceptuellement au cours des temps. Son importance et sa signification ont certainement été créées et transmises à travers un certain nombre de pratiques de construction mémorielle, représentatives de l’identité culturelle et de la cohésion sociale.

This paper uses a threshold adjustment methodology to find out whether price transmission over the cod value chain between Norway and Portugal is asymmetric. The basic setting relies on price theory and the relationship between prices in the fish market. Empirical tests of price transmission use a cointegration framework similar to many other non-stationary time series analyses. However, it appears that testing for asymmetric price transmission has not been done so often in the fish market, despite the recent availability of non-linear time series techniques designed to this end. TAR and M-TAR adjustment models can be used in this context. Our results show that while the three price series used in the cod value chain between Norway and Portugal are cointegrated, there is no evidence of asymmetric price adjustment in this market.

Submitted by Patrícia Alexandra Simões (patricia.simoes@iscte.pt) on 2008-11-11T16:59:21Z No. of bitstreams: 1 Dias,Ferreira&Menezes,R&Asche,F;SystemsDynamicsandTimeSeriesAnalysis...;EGG;VolXI;Nº2;ISCTE;Lx;Set2006.pdf: 3102200 bytes, checksum: ca4c9c4bbcf287631e8434f9fa750765 (MD5) Made available in DSpace on 2008-11-20T15:40:04Z (GMT). No. of bitstreams: 1 Dias,Ferreira&Menezes,R&Asche,F;SystemsDynamicsandTimeSeriesAnalysis...;EGG;VolXI;Nº2;ISCTE;Lx;Set2006.pdf: 3102200 bytes, checksum: ca4c9c4bbcf287631e8434f9fa750765 (MD5) Previous issue date: 2006-09

One of the most popular concepts used to measure the risk and the uncertainty is the variance and/or the standard-deviation. In this paper we explore the potentialities of the entropy as a measure of uncertainty in financial markets, and simultaneously verify if this measure take into account some basic assumptions of the portfolio management theory, namely the effect of diversification.

The extent to which demand and supply shocks are transmitted in the value chain is an important topic. As many value chains cross international borders exchange rate pass through is an important element in this context. In this paper a multivariate system that allow us to test different hypothesis with respect to the value chain is specified. This include tests of whether there is a link between the different stages in the value chain, whether the exchange rate pass through is complete and whether price signals are fully transmitted. Different exogeneity assumptions are testable hypothesis, and one can avoid the simultaneity problem associated with the common single equation specifications. Moreover, one can also test whether the exchange rate is determined outside the system, as well as testing for price leadership. An application is provided for the value chain for cod between Norway and Portugal.

Submitted by Patrícia Alexandra Simões (patricia.simoes@iscte.pt) on 2008-11-11T17:22:25Z No. of bitstreams: 1 Dias,J.F&Menezes,R&Filipe,J&Guia,F...;ACadeiadeValordoBacalhauentreaNoruegaePortugal;EGG;N.º3;Lisboa;ISCTE;Dez2002.pdf: 3442212 bytes, checksum: a0b7f6f770ffa51da131178ffbbcfbee (MD5) Made available in DSpace on 2008-11-20T15:57:12Z (GMT). No. of bitstreams: 1 Dias,J.F&Menezes,R&Filipe,J&Guia,F...;ACadeiadeValordoBacalhauentreaNoruegaePortugal;EGG;N.º3;Lisboa;ISCTE;Dez2002.pdf: 3442212 bytes, checksum: a0b7f6f770ffa51da131178ffbbcfbee (MD5) Previous issue date: 2002-12

In this report we investigate the value chains for two of the most important species in the sea food trade in Europe, cod and salmon, using only price data. For cod we investigate value chains from Norway to Portugal and within the UK, while we investigate the value chains from Norway and the UK into France and from Norway to Finland for salmon. For cod, both value chains seem highly competitive, although there is also increased concentration. As expected, given that several market integration studies have shown that Norwegian and Scottish salmon are close substitutes, the value chains between the two producers are also related. The value chains appear to be competitive at the first stages upstream. When one goes further up in the chain the picture is less clear. At some stages the chain still seems competitive, though this is most commonly associated with traditional chains where there are still small firms, and for the least processed products. The evidence against competition is strongest when the retailers are supermarkets. However, this does not seem to be a sign of utilization of market power, as supermarkets tend to have lower prices. Hence, for both species higher concentration mainly seems to be a necessary adjustment to exploit scale economies in new distribution technologies.

Submitted by Patrícia Alexandra Simões (patricia.simoes@iscte.pt) on 2008-11-11T16:47:25Z No. of bitstreams: 1 Dias, JFerreira&Filipe,J&Guia,F...;ASagadoFielAmigo-AsIndústriasPortuguesasdoBacalhau;EGG;N.º1;Lisboa;ISCTEJul2001.pdf: 2765726 bytes, checksum: d8c68b9a8a674408ea47f70a0b008452 (MD5) Made available in DSpace on 2008-11-20T16:53:05Z (GMT). No. of bitstreams: 1 Dias, JFerreira&Filipe,J&Guia,F...;ASagadoFielAmigo-AsIndústriasPortuguesasdoBacalhau;EGG;N.º1;Lisboa;ISCTEJul2001.pdf: 2765726 bytes, checksum: d8c68b9a8a674408ea47f70a0b008452 (MD5) Previous issue date: 2001-07