Browsing by Issue Date, starting with "2011-01"
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- Material de Apoio às aulas de GeometriaPublication . Martins, Maria do CarmoA capacidade para simular o movimento e a manipulação de objectos num plano é fundamental em todos os sistemas de computação gráfica. Estes processos são descritos em termos de: translações; variações de escala ("Scaling"); rotações; reflexão em recta (ou espelhamento); deformação ou cisalhamento ("Shearing"); Reflexão deslizante ou translação reflectida. O nosso objectivo consiste em descrever estas operações numa forma matemática, mostrar como elas podem ser utilizadas na obtenção do movimento e da manipulação de objectos.
- Empirical analysis of the Hsia option-pricing based model cost of capitalPublication . Neves, João C.; Pimentel, PedroThe cost of capital is a fundamental concept in strategic decisions such as capital investments, capital structure, new issues, mergers and acquisitions, spin-offs and other corporate restructurings. This paper explores empirically the option-based model developed by Hsia (1991) for estimating the cost of equity and the cost of capital of the firm. The composition of the sample in this exploratory study is all 17 non-financial companies listed in the Euronext Lisbon that are included in the market index PSI20. The Hsia model is used for estimating the cost of equity and the cost of capital of the firm for these 17 companies and is compared to the estimates obtained from the Capital Asset Pricing Model (CAPM) and the traditional weighted average cost of capital (WACC). The difference between the means of the cost of equity estimated by Hsia model and CAPM is not statistically significant at 1% level and their correlation of 46.2% is statistically significant at 1% level. However, the differences at the individual level are quite large. One of the limitations found in this study was the inconsistency on the computation of the cost of debt. The problem arise from the fact that the cost of debt do not follow the pattern expected in the theory, but we also find that the Hsia model is unable to deal with potential inconsistencies of the financial market.
- The revival of classical political economy and the Cambridge tradition: from scarcity theory to surplus theoryPublication . Martins, Nuno O.Hilary Putnam and Vivian Walsh argue that Amartya Sen's contribution can, like the writings of Piero Sraffa, be best interpreted as a revival of classical political economy, in which Sen brings back into economics a richer conception of the human agent, and a moral dimension. Sen criticises the conception of rationality that underpins mainstream microeconomic theory, and suggests an alternative framework that can accommodate a variety of motivations, including moral motivations, as will be argued here. Furthermore, the work of Sen, and other authors of the Cambridge tradition who also devoted much time to the revival of classical political economy, are complementary in many respects, and provide the basic tools for an alternative economic theory, which is centred on the economic, social and ethical analysis of the production and distribution of the economic surplus, and not on the modelling of the activity of optimising agents in a context of scarcity. While the notion of scarcity is very important for the analysis of poverty and deprivation that Sen undertakes, the central issue to address, in order to explain the causal mechanisms behind scarcity, poverty and deprivation, concerns the study of the production and distribution of the economic surplus.
- High Speed rail transport valuation and conjuncture shocksPublication . Couto, Gualter; Nunes, Cláudia; Pimentel, PedroIn the present paper we derive the optimal investment policy of investment in the high speed rail (HSR) project, under uncertainty, using the real options analysis (ROA) framework. We assume that the HSR demand, the main source of uncertainty, follows a geometric brownian motion with random jumps, complying with abrupt change of level caused by random events. The occurrence of such events is caused by external shocks. We assess the impact of these shocks in the HSR demand threshold, along with the investment opportunity value, and the option to differ. We consider several distributions for these jumps, and we compare with the base-line case (where exogeneous jumps are not considered).
- Morphometry of the epidermis of an invasive megascoelecid earthworm (Amynthas gracilis, Kinberg 1867) inhabiting actively volcanic soils in the Azores archipelagoPublication . Cunha, Luís; Campos, Itxaso; Montiel, Rafael; Rodrigues, Armindo; Morgan, AndrewFor the first time, the structure, dimensions, and composition of the epidermis of an invasive earthworm species that has successfully colonized hostile conditions in actively volcanic soil on Sao Miguel (Azores) have been measured. Metal concentrations in actively volcanic (Furnas) and volcanically inactive(Fajã) soils were similar; however, Furnas soil was characterised by elevated temperature (10 1C differential), relative hypoxia, extremely high CO2 tension, and accompanying acidity. The epidermis of earthworm’s resident at Fajã was approximately twice the thickness of the epidermis of conspecifics resident in Furnas soil. Reference worms transferred to Furnas soil for 14 days experienced an epidermal thinning of approximately 51%. In comparison, when Furnas earthworms were transferred to mesocosms at the relatively benign Fajã site, their epidermal thickness increased by approximately 21%over 14 days. Earthworms resident in Furnas soil had higher goblet cell counts than the residents of volcanically inactive soil on a neighbouring island (S.Maria). Transferring worms from S.Maria to mesocosmsat Furnas induced a significant increase in goblet cell counts. Clearly, the active volcanic environment at Furnas poses a multifactorial stress challenge to the epigeic A. gracilis colonizer.
- Evaluation of the surrender and the minimum guaranteed rate of return options in life insurance productsPublication . Pimentel, Pedro; Pereira, RicardoThis paper aims to value a Guaranteed Investment Contract (GIC), offered by insurance companies, with a minimum rate of return and an option to surrender the contract (surrender option) at any time before the maturity date. The valuation framework uses a set of different models to value each one of these two options included on a GIC contract commercialized by a Portuguese financial group. We estimate that the surrender option value is around 1.18 percent of the net premium and that the value for the minimum guaranteed rate of return option varies between 0 an 7 percent, according to the used model.
- Combining two multimetric indices for the assessment of water quality using seaweeds over a wide latitudinal gradientPublication . Wallenstein, Francisco; Neto, Ana I.; Rodrigues, Armindo; Wilkinson, Martin
- The subterranean fauna of a biodiversity hotspot region - Portugal: an overview and its conservationPublication . Reboleira, Ana Sofia; Borges, Paulo A. V.; Gonçalves, Fernando; Serrano, Artur R. M.; Oromí, PedroAn overview of the obligate hypogean fauna in Portugal (including Azores and Madeira archipelagos) is provided, with a list of obligated cave-dwelling species and subspecies, and a general perspective about its conservation. All the available literature on subterranean Biology of Portugal since the first written record in 1870 until today has been revised. A total of 43 troglobiont and 67 stygobiont species and subspecies from 12 orders have been described so far in these areas, included in the so-called Mediterranean hotspot of biodiversity. The subterranean fauna in Portugal has been considered moderately poor with some endemic relicts and it remains to be demonstrated if this fact is still true after investing in standard surveys in cave environments. The major problems related to the conservation of cave fauna are discussed, but it is clear that the protection of this specialized fauna implies an adequate management of surface habitats.
- Estimating the impacts of eliminating fisheries subsidies on the small island economy of the AzoresPublication . Fortuna, Mário; Carvalho, Natacha; Rege, SameerSubsidies that reduce the costs incurred by fishers and increase profits for the industry can insulate fishers from economic signals, countering the economic incentive to stop fishing when it is unprofitable. Subsidies can thus be a major impediment to achieving economically productive fisheries, exacerbating overexploitation and delaying the necessary industry adjustments, particularly in the absence of effective management systems. Although some fisheries are profitable without government support, several studies have shown that many European fishing fleets are either running losses or returning low profits. In most cases operating costs are higher than gross revenue, resulting in a negative net contribution of fisheries to the economy, the deficit of which is largely funded by subsidies. Thus the cost of fishing to the public budget exceeds the total value of the catches. Recently, fishery subsidies have received much attention with a mounting literature on the urgent need to reduce capacity-enhancing subsidies and begin focusing on developing a profitable and sustainable industry that can adapt to changing economic and environmental conditions. Simple economic models showing how subsidies affect profits and therefore provide incentives for increased fishing effort have accompanied a number of overviews of subsidies published by leading intergovernmental and research institutions. A number of case studies have also illustrated the critical link between fleet capacity and subsidies and that some categories of subsidies are more distorting than others. However, most of the studies have been limited to estimating the value of these subsidies, and usually at the multinational or global level. None so far, to our knowledge, has estimated the economy-wide impact of reducing or eliminating fishing subsidies even though there is a growing consensus that subsidies should gradually be terminated. Moreover, the Fisheries Secretariat believes that capacity enhancing and fuel subsidies should be stopped immediately. Nonetheless, the new financial instrument of the CFP, the European Fisheries Fund (EFF 2007-2013), although an improvement on its previous homologous (FIFG 2000-2006), contains some ambiguous elements, which could open up for further increase of fishing capacity. A long-term approach is needed that encompasses more fundamental changes than using for example more efficient engines that initially reduce fuel consumption but in the long-run worsen the situation by contributing to increasing fishing effort on already overexploited stocks. On account of the global fisheries crises, highly subsidised fisheries and the anticipated reforms of the CFP, this study aims at estimating the impact of eliminating cost-reducing and capacity-enhancing fisheries subsidies on the Azorean economy. In particular, this study sets out to measure the impact of such a shock on various macro and micro variables pertaining to the regional economy using a dynamic CGE model based on a SAM for the Azores.
- Creating emergency plans : Risk Communication and Families' Preparedness for Seismic Events in the AzoresPublication . Rego, Isabel Estrela; Arroz, Ana Margarida Moura; Caldeira, Suzana Nunes; São Marcos, Rita; Nava, Joana Perry
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