Firms and aggregate dynamics

We investigate the role of permanent and transitory shocks for firms and aggregate dynamics. We find that permanent shocks to productivity and permanent shifts in the composition of output explain at least four-fifths of firms’ dynamics. However, these permanent shocks are almost uncorrelated across firms and are therefore less relevant for aggregate dynamics. Transitory shocks, on the other hand, are not very important at the firm level,but they account for most of the volatility of aggregate hours and output, because they are significantly correlated across firms. Finally, we try to make some progress on the interpretation of the shocks.

Predicting market movement with Artificial Neural Networks

This paper presents an application of an Artificial Neural Network (ANN) to the prediction of stock market direction in the US. Using a multilayer perceptron neural network and a backpropagation algorithm for the training process, the model aims at learning the hidden patterns in the daily movement of the S&P500 to correctly identify if the market will be in a Trend Following or Mean Reversion behavior. The ANN is able to produce a successful investment strategy which outperforms the buy and hold strategy, but presents instability in its overall results which compromises its practical application in real life investment decisions.

Leverage instability and persistence: Evidence from the United States and Europe

We find that leverage behavior both in level and time-series variation is very similar between the United States and Europe throughout the 1990-2013 period. Leverage regimes are simultaneously unstable and persistent for both regions. We define instability as the extent to which firms largely deviate from their long-term leverage mean, while persistence as the extent to which today’s leverage influences its future levels. We then show that this simultaneous evidence imply a mean-reversion behavior of leverage and discuss some of its implications for future research on this field.

Valuing an offshore exploration project through real options analysis

This thesis applied real options analysis to the valuation of an offshore oil exploration project, taking into consideration the several options typically faced by the management team of these projects. The real options process is developed under technical and price uncertainties, where it is considered that the mean reversion stochastic process is more adequate to describe the movement of oil price throught time. The valuation is realized to two case scenarios, being the first a simplified approach to develop the intuition of the used concepts, and the later a more complete cases that is resolved using both the binomial and trinomial processes to describe oil price movement. Real options methodology demonstrated to be capable of assessing and valuing the projects options, and of overcoming common capital budgeting methodologies flexibility limitation. The added value of the application of real options is evident, but so is the method's increased complexity, which adversely influence its widespread implementation.

Castor fiber na gruta do Caldeirão. Existência, distribuição e extinção do castor em Portugal

Beaver only had been found in Portugal in a Chalcolithic locality, the Vila Nova de S. Pedro castrum. It has now been identified in the Upper Paleolithic (Solutrean) from Gruta do Caldeirão, near Tomar. The species has been found recently at «Gruta do Almonda»; 4 teeth were collected in bed C, older than a Solutrean sequence (see Anexo for details). The species seems to have been rare, as it was also the case with portuguese Miocene Castoridae Enroxenomys minutus and Chalicomys jaegeri. If account is taken of the presence in the Middle Ages until Castille of words meaning beaver (relared to the popular latin Fiber/Biber), it is obvious that these animais still existed then. Such nouns were largely predominant over rhe rather erudite latin (greek deríved) words as Castor,-óris and derived ones, as it could be expected. This allowed us to recognize that veiro should be the corresponding word with Fiber affinities in archaic portuguese. It was previously supposed to mean only expensive furs then imported into Portugal. Indeed it was also a zoonym. Anywày, beaver should be scarce by XIIIth century since it is not included in the quite detailed price list imposed by the «Lei da Almotaçaria» from December 26, 1253 (see Quadro II). Toponyms in veiro and derived words (fig. 2; Quadro III) (plural, feminines, diminutives, inhabited places) give a resrrictive view of rhe Middle Age distribution. Some of them are certainly older than Portugal itself (firsr half of XIlth cenrury); others existed by the XIVth century bur were probably older. Some rare toponyms seem to be derived from the erudite latin Castor,-óris. Nothing suggests that these words were still in use as zoonyms during the Middle Ages. All toponyms are located in regions near rivers and other freshwaters ecologically suitable for beavers, so we can approximately retrace its former, Middle Age disrribution in Portugal (fig. 2; Quadro III). Most of them are locared in the Center-West and Northwest of Portugal, with a suitable c1imate (rainfall in general over 800 mílimerers per year); the only sure geographical exception is Veiros, in Alto Alentejo province, in a region with comparable precipitations and less dry climate conditions than mosr of the territories South of rhe Tagus. There are less and less of these toponyms towards rhe South and the inner part of the country, and they are enrirely lacking in all drier regions from Trás-os-Montes, Beira, Alentejo beyond Tagus' basin, and in Algarve. Nothing suggests beavers lived there, No post-medieval toponym is known, nor any reference after middle XVth century. No such locality was at, or close by to, any frontier. Hence the hypothesis of veiro (et al.} as meaning but points where expensive furs (supposedly known as veiros in general but without c1early saying from what animal they were obrained from) is to be discarded. During the Middle Ages, beaver discriburion concerned all the main river basins from Minho to Tagus ones. Quite rarefied in rhe XIIIth, the beavers may have disappeared from Portugal during the XVth century. Ecological requiremenrs restricted their former distriburion. Vulnerability to natural causes (i.e., severe drought) and to human pressure may have accounted heavily for this species' extinction. Last (1446) reference for Portugal known to us suggests the species was by then almost extinct.

Diversity in Teams: Source of Conflict or Source of Creativity? Investigating Hidden Mental Models

The workforce in organizations today is becoming increasingly diverse. Consequently the role of diversity management is heavily discussed with respect to the question how diversity influences the productivity of a group. Empirical studies show that on one hand there is a potential for increasing productivity but on the other hand it might be as well that conflicts arise due to the heterogeneity of the group. Usually according empirical studies are based on interviews, questionnaires and/or observations. These methods imply that answers are highly selective and filtered. In order to make the invisible visible, to have access to mental models of team members the paper will present an empirical study on the self-understanding of groups based on an innovative research method, called “mind-scripting”.

Castor fiber na gruta do Caldeirão Existência, distribuição e extinção do castor em Portugal

Beaver only had been found in Portugal in a Chalcolithic locality, the Vila Nova de S. Pedro castrum. It has now been idenrified in the Upper Paleolithic (Solurrean) from Gruta do Caldeirão, near Tomar. The species has been found recently at «Gruta do Almonda»; 4 teeth were collected in bed C, older than a Solutrean sequence (see Anexo for details). The species seems to have been rare, as it was also the case with portuguese miocene Castoridae Enroxenomys minutus and Chalicomys jaegeri. If account is taken of the presence in the Middle Ages until Castille of words meaning beaver (related to the popular latin Fiber/Biber), it is obvious that these animals still existed then. Such nouns were largely predominant over the rather erudite larin (greek derived) words as Castor, -óris and derived ones, as it could be expected. This allowed us to recognize that veiro should be the corresponding word with Fiber affinities in archaic portuguese. It was previously supposed to mean only expensive furs then imported into Portugal. Indeed it was also a zoonym. Anyway, beaver should be scarce by XIIIth century since it is not included in the quite detailed price list imposed by the «Lei da Almotaçaria» from December 26, 1253 (see Quadro II). Toponyms in veiro and derived words (fig. 2; Quadro III) (plural, feminines, diminutives, inhabited places) give a restrictive view of the Middle Age distribution. Some of them are certainly older than Portugal itself (first half of XIIth century); others existed by the XIVth century but were probably older. Some rare toponyms seem to be derived from rhe erudite latin Castor, -óris. Nothing suggests that these words were still in use as zoonyms during the Middle Ages. All toponyms are located in regions near rivers and other freshwaters ecologically suitable for beavers, so wecan approximately retrace irs former, Middle Age distribution in Portugal (fig. 2; Quadro III). Most of them are located in the Center-West and Northwest of Portugal, with a suitable c1imate (rainfall in general over 800 milimeters per year); the only sure geographical exception is Veiros, in Alto Alentejo province, in a region with comparable precipitations and less dry climare conditions than most of the territories South of the Tagus. There are less and less of these toponyms towards the South and the inner part of the country, and they are enrirely lacking in ali drier regions from Trás-os-Montes, Beira, Alentejo beyond Tagus' basin, and in Algarve. Nothing suggests beavers lived there, No pose-medieval toponym is known, nor any reference after middle XVth century. No such locality was at, or close by to, any frontier. Hence the hypothesis of veiro (e: al.) as meaning but points where expensive furs(supposedly known as veiros in general but without clearly saying from what animal they were obtained from) is to be discarded. During the Middle Ages, beaver distribution concerned all the main river basins from Minho to Tagus ones. Quice racefied in the XIIIth, the beavers may have disappeared from Portugal during the XVth century. Ecological requirements restricted their former distribution. Vulnerability to natural causes (i.e., severe drought) and to human pressure may have accounted heavily for this species extinction. Last (1446) reference for Portugal known to us suggests the species was by then almost extinct.

Spatio-temporal analyses of the relationship between armed conflict and climate change in the eastern Africa

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

The macroeconomic effects of (different) oil shocks: A VAR approach

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Differential exploitation of cashew - a low conflict crop - by sympatric humans and chimpanzees

Modification of natural areas by human activities mostly has a negative impact on wildlife by increasing the geographical and ecological overlap between people and animals. This can result in escalating levels of competition and conflict between humans and wildlife, for example over crops. However, data on specific crops and crop parts that are unattractive to wildlife yet important for human livelihoods are surprisingly scarce, especially considering their potential application to reducing crop damage by wildlife. Here we examine the co-utilization of a nationally important and spatially abundant cash crop, cashew Anacardium occidentalis, by people and chimpanzees Pan troglodytes verus inhabiting a forested–agricultural matrix in Cantanhez National Park in Guinea-Bissau. In this Park people predominantly harvest the marketable cashew nut and discard the unprofitable fruit whereas chimpanzees only consume the fruit. Local farmers generally perceive a benefit of raiding by chimpanzees as they reportedly pile the nuts, making harvesting easier. By ensuring that conflict levels over crops, especially those with high economic importance, remain low, the costs of living in proximity to wildlife can potentially be reduced. Despite high levels of deforestation associated with cashew farming, these findings point to the importance of cashew as a low-conflict crop in this area.

Oil price shocks and the Portuguese economy since the 1970s

This paper assesses empirically the effect of oil price shocks on Portuguese aggregate economic activity, industrial production and price level. We take the usual multivariate VAR methodology to investigate the magnitude and stability of this relationship. In doing so, we follow the approach presented in the recent literature and adopt different oil price specifications. We conclude that, as for most industrialized countries, the nature of this relationship changed in the mid-1980s. Furthermore, we show that the main Portuguese macroeconomic variables have become progressively less responsive to oil shocks and the adjustment towards equilibrium has become increasingly faster.

Cost efficiency in the Portuguese water sector: The case of multimunicipal systems operating at the bulk level

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

The Course of Conflict. A Study in the Thought of Paul Ricoeur

Esta tese leva a cabo uma clarificação conceptual e uma reconstrução histórica da noção de conflito, tal como ela aparece na filosofia. Num primeiro momento, analisa-se o fenómeno do conflito na fonte Grega (em Homero, Heraclito, Platão, nas tragédias gregas e nas formas de interação agonística no espaço público) e na filosofia moderna (principalmente em Kant, Hegel e Marx). Num segundo momento, estabelece-se, nos seus traços gerais, uma cartografia da recuperação desta noção na contemporaneidade através da discussão das contribuições provenientes da teoria crítica (Habermas, Honneth, Hunyadi), da sociologia pragmática (Boltanski, Thévenot) e da filosofia política anglo-saxónica (Rawls, Walzer, Taylor), entre outras. Estas partes iniciais da tese desembocam numa análise aprofundada da obra do filósofo francês Paul Ricoeur e das muitas instanciações do conflito nessa obra, naquilo a que chamo o “percurso do conflito” no pensamento de Ricoeur. Neste “percurso do conflito” o objetivo é duplo: por um lado, provar que o conflito é a pedra de toque não só da filosofia de Ricoeur, mas também de um grande conjunto de outros autores; por outro lado, que é necessário reavaliar o papel desta noção no debate contemporâneo e que nesse contexto a filosofia de Ricoeur e as suas análises finas e plurais podem ser de uma grande utilidade. Assim sendo, este “percurso do conflito” divide-se em três partes, as quais lidam com diferentes tipos de conflito: conflitos “existenciais”, “hermenêuticos” e “práticos”. Ao longo destas partes, várias disciplinas são chamadas à colação, como a hermenêutica, a psicanálise e a filosofia prática (ética, filosofia política e filosofia social), numa tentativa de esclarecer os diferentes fenómenos em causa. Em última instância, chega-se à conclusão que o conflito é inevitável em filosofia, tal como na vida, mas que este não é (pelo menos não em todas as suas formas e instanciações) um fenómeno estritamente negativo; por vezes, os conflitos podem ser criativos e positivos. Porém, aceitar este facto implica igualmente consentir que o reconhecimento dos conflitos está intrinsecamente ligado à busca de soluções para eles, formas de lidar com eles e torná-los criativos e positivos. Para que possa ser compreendido, em traços gerais, como é que estes procedimentos funcionam, esta tese elabora uma tipologia de diferentes tipos de conflito e respetivas formas de lidar com eles, mediando-os, conciliando-os ou, nalguns casos, apenas aceitando a sua existência e mesmo multiplicando-os. A busca da melhor solução tem sempre de ser operada caso a caso. Nas partes finais da tese, e partindo das análises de Ricoeur e dos outro autores apresentadas ao longo da mesma, delineia-se o projeto de uma filosofia social hermenêutica e argumenta-se que aquilo de que precisamos hoje em dia é de uma nova crítica da razão, uma “crítica da razão miserável” que possa repensar o mundo social em novos termos e que, ao fazê-lo, possa evitar os perigos do reducionismo nas suas múltiplas formas.

Evolution of reputation in networks: A mean field game approach

This work models the competitive behaviour of individuals who maximize their own utility managing their network of connections with other individuals. Utility is taken as a synonym of reputation in this model. Each agent has to decide between two variables: the quality of connections and the number of connections. Hence, the reputation of an individual is a function of the number and the quality of connections within the network. On the other hand, individuals incur in a cost when they improve their network of contacts. The initial value of the quality and number of connections of each individual is distributed according to an initial (given) distribution. The competition occurs over continuous time and among a continuum of agents. A mean field game approach is adopted to solve the model, leading to an optimal trajectory for the number and quality of connections for each individual.

Escalation of conflict in FMCG industry: A negotiation case

This work project develops a case-study to be used in Negotiation courses, both in Masters programs and in executive education workshops. The case-study is based on a real-life negotiating situation in Belgium between Unilever, the second largest Fast Moving Consumer Goods (FMCG) company in the world, and Delhaize, one of the most important Belgium’s retailers, with a significant international presence. We also present an analysis of the negotiation based on relevant literature. First, a brief literature review is presented about how to deal with multiple-issue negotiations and how to deal with processes of escalation of conflict. These concepts are then applied to the analysis of the case-study.