Labor Adjustment Costs in a Panel of Establishments: A Structural Approach

This paper estimates a structural model of the employment decision of the firm. Our establishment level data displays an extreme degree of rigidity in that employment levels are largely constant throughout our sample. This can be due to the fact that establishments face large shocks but also large adjustment costs, or alternatively that they incur no adjustment costs but that shocks are negligible. Given our identifying assumptions, we find that rigidity is due to adjustment costs and not to the shock process. We further find that these costs reduce the value of the firm as much as 5%. Finally, small fixed costs of adjustment have a large impact on entry and exit job flows.

How the gold standard functioned in Portugal: an analysis of some macroeconomic aspects

This paper studies the Gold Standard in Portugal. It was the first country in Europe to join Great Britain in 1854. The principle of free gold convertibility was abandoned in 1891. For the purposes of a macroeconomic study, we also extended the analysis up to 1913. Our study points out the mistake of comparing different systems with the same indicators. Examination of demand, supply and monetary shocks in the context of a VAR model confirm the idea that the principles of classical economics are appropriate for the Gold Standard in Portugal.Gold Standard, Macroeconomic Stability, Convertibility, Portugal, VAR and Unit Roots

How the Gold Standard Functioned in Portugal: An Analysis of Some Macroeconomic Aspects

The purpose of this study is to improve understanding of the gold standard period in Portugal through comparison with other monetary systems that were operated afterwards. Portugal was the first country in Europe to join Great Britain in the gold standard, in 1854, and it adhered to it for quite a long time. The principle of free gold convertibility of the Portuguese currency at a fixed price was abandoned in 1891, even though the classical gold standard as an international monetary system only began to fall apart as a result of the upheavals of the First World War. For the purposes of a macroeconomic study, we can thus first look at the expansion of the functioning of the gold standard in Portugal up to 1913. In addition to a desire to share the same monetary system as its trading and financial partner, the low price of gold and the domestic circulation of British gold coins also played a part, along with other factors, in the adoption of the gold standard in Portugal. While it was in force, it provided a nominal stable anchor and a mechanism of credible commitment, even though Portugal’s monetary authorities broke the “rules of the game”. Our analysis points out the mistake of comparing the stability of different monetary systems with the same indicators. The application of a VAR model enabled us to isolate the period 1854-1891 as being the one that actually corresponds to what we expect of gold standard behaviour. Examination of demand, supply and monetary shocks yields interesting results that confirm the idea that the principles of classical economics are appropriate for the gold standard period.Gold Standard, Macroeconomic Stability, Convertibility, Portugal, VAR, Unit Roots

The Portuguese Public Finances and the Spanish Horse

This study is based on the idea that inadequate use of fiscal policy through restrictive policies shifts the short-run demand curve that in turn induces shifts in the long-run supply curve leading to a dynamic reduction of growth. The analogy with the old metaphor of the Spanish horse seems obvious. We apply this idea to Portugal to 2002-2009, we will prove that in order not to be caught in the horse’s trap we have to keep the concept of potential output in the evaluation of the structural budget balance instead of replacing it by a trend indicator, which, can lead to a sustainable reduction of the “food” and consequently to a disaster. The goal of full employment is no longer present in the idea of zero public balances. In the medium-term, the cycles will offset each other when calculated in relation to a trend and thus the same applies to budget balances as defined in the Stability and Growth Pact (SGP). If actual output moves away persistently from full employment output, trend output will also move away from full employment. As a consequence, expenditures will tend to increase and incomes to decrease. This situation creates deficits that should be corrected by the SGP. This correction will lead to a reduction in demand and thus in actual output and therefore, necessarily, in trend output itself. We present an empirical solution to this problem based on the concept of trend output in order to correct its inflection after 2002. This analysis has two drawbacks, the influence of deficits in the prices of non-tradable goods and the fact that we may not have food to give to our horse. This is the case if public debt is too high. Nevertheless, this study shows that the criteria and methods that are used by the SGP in the definition of fiscal policy are incorrect.Budget deficit, cyclically adjusted budget balance, fiscal policy, Hodrick-Prescott filter and output gap.

Exchange Rate Target Zones: A Survey of the Literature

This work selectively reviews the literature on exchange rate target zones and their theoretical and empirical methodologies and examines whether they can be used to clarify to what extent this type of exchange rate regime could contribute to greater exchange rate stability. We discuss the main contributions of the first and second generations of exchange rate target zone models. In an attempt to reconcile the poor empirical performance of the Krugman (1991) model with the reality of exchange rate target zone regimes, this line of research integrates target zones with alternative underlying economic models, such as imperfect credibility, intra-marginal interventions and sticky price models. It was thus possible to understand the correlations observed between the exchange rate, its fundamentals determinants and the interest rate differential, and to explain the fact that the statistical distribution of the exchange rate is hump-shaped rather than U-shaped. This implies that the initial emphasis of target zone models on nonlinearities, “honeymoon effect”, “smooth pasting” and marginal interventions has vanished. Exchange rate target zones are better described as similar to managed floating regimes with intra-marginal interventions, with some marginal interventions when the exchange rate reaches the edges of the floating band.Exchange rate target zones, imperfect credibility, intra-marginal interventions realignments and sticky prices.

Exchange Rate Mean Reversion within a Target Zone: Evidence from a Country on the Periphery of the ERM

The aim of this study is to assess to what extent the Portuguese participation in the European Monetary System (EMS) has been characterized by mean reverting behaviour, as predicted by the exchange rate target zone model developed by Krugman (1991). For this purpose, a new class of mean reversion tests is introduced. The empirical analysis of mean reversion in the Portuguese exchange rate shows that most of the traditional unit root and stationarity tests point to the nonstationarity of the exchange rate within the band. However, using a set of variance-ratio tests, it was possible to detect the presence of a martingale difference sequence. This suggests that the Portuguese foreign exchange market has functioned efficiently, allowing us to conclude that the adoption of an exchange rate target zone regime has contributed decisively to the creation of the macroeconomic stability conditions necessary for the participation of Portugal in the euro area.difference sequence, mean reversion, stationarity, target zones and unit roots

Produção de bioetanol a partir de SSLs: S. stipitis vs S. cerevisiae

Mestrado em Biotecnologia - Biotecnologia Industrial e AmbientalO objectivo desta dissertação foi a comparação da produção de bioetanol de 2ª geração por Scheffersomyces stipitis (em suspensão e imobilizada) e por duas estirpes industriais de Saccharomyces cerevisiae. Os substratos utilizados para a realização das fermentações foram os Licores de Cozimento ao Sulfito Ácido (SSLs) provenientes de madeira de resinosas (HSSL) e de madeiras de folhosas (SSSL – Domsjö hydrolysate). O HSSL e o SSSL são sub-produtos da indústria de pastas de papel, resultando do processo de cozimento ao sulfito com magnésio e sódio, respetivamente. Além de lenhosulfonatos, estes SSLs contêm monossacarídeos, destacando-se a glucose, xilose e manose. O ácido acético, composto inibidor da fermentação alcoólica por leveduras, também está presente em concentrações relativamente elevadas (≥ 5.0 g . L-1). O HSSL foi pré-tratado físico-quimicamente e submetido a uma remoção biológica de inibidores com P. variotii, enquanto o Domsjö hydrolysate foi utilizado sem qualquer tratamento. S. stipitis e S. cerevisiae são leveduras extensamente estudadas devido à sua capacidade de fermentação de pentoses e hexoses, respetivamente. Num estágio prévio às fermentações dos SSLs, as leveduras foram pré-adaptadas em 60% HSSL ou 40% SSSL. Os máximos de rendimento (0.440 g etanol . g açúcares-1) e produtividade em etanol (0.885 g etanol . L-1 . h-1) foram obtidos nas fermentações com S. cerevisiae TMB 3500 em SSSL, sendo estas as variáveis com maior potencial para aplicação industrial. Embora a cultura suspensa de S. stipitis tenha resultado numa menor produtividade (0.010 g etanol . L-1 . h-1), a optimização do fornecimento de oxigénio ao biorreator deverá conduzir ao aumento da produtividade volumétrica em etanol. A imobilização celular e o controlo do pH em 5.5 nas fermentações com S. stipitis melhoraram a eficiência fermentativa ao aumentarem a produção de etanol em 1.3 e 1.6 vezes, respetivamente. Quando aplicadas simultaneamente, estas duas condições aumentaram o rendimento em etanol 2.2 vezes, sugerindo que (i) a imobilização numa matriz de alginato de cálcio protegeu a levedura dos inibidores químicos e que (ii) o controlo de pH em 5.5 foi determinante para a produção de etanol a partir de HSSL biologicamente pré-tratado. Os resultados comprovam que ambos os SSLs são potenciais substratos para a produção de bioetanol de 2ª geração usando S. stipitis ou S. cerevisiae, sob o conceito de biorefinaria.The aim of this work was the comparison of second-generation bioethanol production by Scheffersomyces stipitis (free-culture and immobilized) and two Saccharomyces cerevisiae industrial strains, using Hardwood Spent Sulphite Liquor (HSSL) or Domsjö hydrolysate (SSSL) as substrate. HSSL and SSSL are side products of pulp and paper industry, from magnesium and sodium-based acidic sulphite pulping, respectively. Besides sulphonated lignin, SSLs contain fermentable sugars, mainly glucose, xylose and mannose. Acetic acid, a known inhibitor of ethanol fermentation by yeasts, is also present in a relatively high content (≥ 5.0 g . L-1). HSSL was previously physico-chemically pretreated and bio-detoxified with P. variotii, whereas SSSL was used without any treatment. S. stipitis and S. cerevisiae are the most widely studied pentose and hexose-fermenting yeasts, respectively. Before fermentations in SSLs, all yeast strains were pre-adapted by growing them in 60% HSSL or 40% SSSL. The highest maximum ethanol yield (0.440 g ethanol . g sugars-1) and productivity (0.885 g ethanol . L-1 . h-1) were obtained using S. cerevisiae TMB 3500 and SSSL. Suspended S. stipitis achieved a lower ethanol productivity (0.010 g ethanol . L-1 . h-1) but further optimization on the supplied oxygen in the fermentor might lead to higher ethanol productivity. Immobilization and pH control at 5.5 on S. stipitis fermentations improved the fermentation efficiency, increasing up the ethanol production by 1.3-fold and 1.6-fold, respectively. When applied simultaneously, these two conditions increased the ethanol yield 2.2-fold, suggesting that (i) immobilization with a calcium-alginate matrix protected the yeast from the inhibitory compounds and (ii) the controlled pH at 5.5 was essential for ethanol production from bio-detoxified HSSL. Results showed that both SSLs are potential substrates for the production of 2nd generation bioethanol by S. stipitis or S. cerevisiae, under the biorefinery concept

Exchange Rate and Interest Rate Distribution and Volatility under the Portuguese Target Zone

The aim of this study is to analyse the exchange rate and interest rate distribution and volatility under the participation of the Portuguese economy in the Exchange Rate Mechanism (ERM) of the European Monetary System (EMS) based on some of the main predictions of the target zone literature. Portugal adopted this exchange rate target zone from April 6 1992 until December 31 1998. During this period, the exchange rate distribution reveals that the majority of the observations lie close to the central parity, thus rejecting one of the key predictions of the Paul Krugman (1991) model. The analysis of the data also shows that exchange rate volatility tended to increase as the exchange rate approached the edges of the band, contrary to the predictions of the basic model. Interest rate differential volatility, on the other hand, seemed to behave in line with theoretical predictions. This suggests an increase in the credibility of monetary policy, allowing us to conclude that the adoption of a target zone has contributed decisively to the creation of the macroeconomic stability conditions necessary for the participation in the European Monetary Union (EMU). The Portuguese integration process should therefore be considered as an example to be followed by other small open economies in transition to the euro area.Exchange rate stability, EMS, Volatility and target zones

Weed management in vineyards, olive groves and orchards

A implementação de culturas perenes, em Portugal, sofreu nas últimas décadas grandes alterações quer na instalação da cultura quer nas técnicas de gestão. Este artigo revê a gestão das infestantes nas principais culturas perenes em Portugal, o que se julga pertinente dado que se tem verificado a implementação de sistemas de modo de produção biológica (MPB) e de produção integrada (MProdi). Por infestante, os autores, consideram as populações de uma dada espécie vegetal que acima de determinados níveis e sob condicionalismos ecológicos particulares sejam responsáveis por prejuízos “líquidos” (balanço benefícios-prejuízos negativo) inaceitáveis em termos económicos e/ou ecológicos ou sociais. Primeiramente, apresentam-se os dados de 2015 relativamente às áreas e produções das culturas perenes mais importantes em Portugal – vinha, olival, pomares de macieira, pereira e citrinos. De seguida, referem-se os principais prejuízos e benefícios das infestantes, salientando-se os estudos relativos aos prejuízos na vinha e os meios de controlo disponíveis mais adotados–mobilização do solo, controlo químico e enrelvamento, as vantagens e inconvenientes de cada método. Por último, refere-se a conveniência da integração das técnicas de gestão, de modo a potenciar os benefícios de cada uma e evitar as suas limitaçõesinfo:eu-repo/semantics/publishedVersio

Exchange Rate and Interest Rate Volatility in a Target Zone: The Portuguese Case

This work examines the participation of the Portuguese economy in the ERM of the EMS based on some of the main predictions of the target zone literature. The exchange rate distribution reveals that the majority of the observations lie close to the central parity, thus rejecting one of the key predictions of the Krugman (1991) model. Using a M-GARCH model however we confirm that there is a trade-off between exchange rate volatility and interest rates differential volatility. These results express the increased credibility of the Portuguese monetary policy, due manly to the modernisation of the banking and financial system and to the progress made in terms of the disinflation process under an exchange rate target zone policy. In accordance to these results we can say that the participation of the Portuguese escudo in an exchange rate target zone was crucial to create the conditions of stability, credibility and confidence necessary for the adoption of a single currency.Credibility, Exchange rate stability, M-GARCH, ERM, EMS, Volatility and target zones