Gestão Integrada dos Recursos Hídricos da Ilha do Maio (Cabo Verde): o Contributo das Águas Subterrâneas

Cabo Verde é constituído por 10 ilhas, sendo a ilha do Maio a mais antiga do arquipélago, com uma área de 269 km2, tendo como comprimento máximo 24100 m, uma largura máxima de 16300 m e uma população total de 6740 habitantes. No que concerne à geomorfologia e geologia, a ilha é considerada plana e é composta por formações eruptivas e sedimentares, sendo as formações sedimentares dominantes na ilha. Apresenta as formações mais antigas de Cabo Verde, de idade jurássica e cretácica. No entanto, não apresenta as formações eruptivas mais recentes como as restantes ilhas. A ilha do Maio enquadra-se num clima do tipo árido e semiárido, com uma temperatura média de 24.5 ºC e uma precipitação anual de 125.4 mm. Estimativas efectuadas com base no modelo do balanço hídrico sequencial diário mostram que cerca de 7% da precipitação corresponde a escoamento superficial e 14.1% a escoamento subterrâneo. Pela aplicação deste modelo e do método do balanço químico do ião cloreto, os recursos hídricos subterrâneos renováveis anualmente na ilha do Maio estão, em ano médio, compreendidos entre 3.44 x 106 m3 e 4.76 x 106 m3.por sua vez, o escoamento total é estimado em 7.8 x 106 m3 anuais, o que equivale a cerca de 21 400 m3/dia. O escoamento subterrâneo na ilha do Maio faz-se globalmente de um modo centrífugo a partir das elevações do maciço central. O gradiente hidráulico assume valores entre 0.05% e 2.9%, sendo que o valor mais baixo ocorre no sector norte da ilha, o que favorece o fenómeno de intrusão salina. Relativamente à qualidade da água, verifica-se que as amostras recolhidas correspondem a águas muito mineralizadas, com valores de condutividade eléctrica compreendidos entre 832 μS/cm e 7730 μS/cm. Por sua vez, os valores de TDS estão compreendidos entre 705.8 mg/L e 4210.4 mg/L. Nestas condições, as águas subterrâneas analisadas podem ser consideradas águas salobras. A fácies hidroquímica dominante é a cloretada sódica, sendo que grande parte das amostras pode ser considerada cloretada-bicarbonatada sódica. Admitindo que a amostragem efectuada tem significado estatístico, poderá dizer-se que, a nível físico-químico, cerca de 20% das águas subterrâneas são próprias para o consumo humano. No que respeita à utilização da água para rega, as águas analisadas apresentam baixo a alto perigo de alcalinização do solo e alto a muito alto perigo de salinização. Em síntese, pode concluir-se que, não obstante o carácter árido da ilha do Maio, a mesma apresenta um potencial de recursos hídricos não negligenciável, eventualmente suficiente para suprir as necessidades hídricas da população. No entanto, o estudo desenvolvido mostra a necessidade de implementar medidas susceptíveis de proporcionarem um aproveitamento sustentado dos recursos hídricos, no quadro da gestão integrada dos recursos hídricos da ilha do Maio.

The informational value of incumbency

This paper proposes an argument that explains incumbency advantage without recurring to the collective irresponsibility of legislatures. For that purpose, we exploit the informational value of incumbency: incumbency confers voters information about governing politicians not available from challengers. Because there are many reasons for high reelection rates different from incumbency status, we propose a measure of incumbency advantage that improves the use of pure reelection success. We also study the relationship between incumbency advantage and ideological and selection biases. An important implication of our analysis is that the literature linking incumbency and legislature irresponsibility most likely provides an overestimation of the latter.

On information and competition in private value auctions

How much information does an auctioneer want bidders to have in a private value environment?We address this question using a novel approach to ordering information structures based on the property that in private value settings more information leads to a more disperse distribution of buyers updated expected valuations. We define the class of precision criteria following this approach and different notions of dispersion, and relate them to existing criteria of informativeness. Using supermodular precision, we obtain three results: (1) a more precise information structure yields a more efficient allocation; (2) the auctioneer provides less than the efficient level of information since more information increases bidder informational rents; (3) there is a strategic complementarity between information and competition, so that both the socially efficient and the auctioneer s optimal choice of precision increase with the number of bidders, and both converge as the number of bidders goes to infinity.

Betting on Hitler: The value of political connections in Nazi Germany

This paper examines the value of connections between German industry andthe Nazi movement in early 1933. Drawing on previously unused contemporarysources about management and supervisory board composition and stock returns,we find that one out of seven firms, and a large proportion of the biggest companies,had substantive links with the National Socialist German Workers Party. Firmssupporting the Nazi movement experienced unusually high returns, outperformingunconnected ones by 5% to 8% between January and March 1933. These resultsare not driven by sectoral composition and are robust to alternative estimatorsand definitions of affiliation.

Quantitative Assessment of Handwriting Evidence: The Value of the Shape of the Letter "A"

To provide a quantitative support to the handwriting evidence evaluation, a new method was developed through the computation of a likelihood ratio based on a Bayesian approach. In the present paper, the methodology is briefly described and applied to data collected within a simulated case of a threatening letter. Fourier descriptors are used to characterise the shape of loops of handwritten characters "a" of the true writer of the threatening letter, and: 1) with reference characters "a" of the true writer of the threatening letter, and then 2) with characters "a" of a writer who did not write the threatening letter. The findings support that the probabilistic methodology correctly supports either the hypothesis of authorship or the alternative hypothesis. Further developments will enable the handwriting examiner to use this methodology as a helpful assistance to assess the strength of evidence in handwriting casework.

Social value orientation as a moral intuition: Decision-making in the dictator game

We studied the decision making process in the Dictator Game and showed that decisions are the result of a two-step process. In a first step, decision makers generate an automatic, intuitive proposal. Given sufficient motivation and cognitive resources, they adjust this in a second, more deliberated phase. In line with the social intuitionist model, we show that one s Social Value Orientation determines intuitive choice tendencies in the first step, and that this effect is mediated by the dictator s perceived interpersonal closeness with the receiver. Self-interested concerns subsequently leadto a reduction of donation size in step 2. Finally, we show that increasing interpersonal closeness can promote pro-social decision-making.

The Value of Private Information within Evolving Groups

This note offers an analytical framework aimed at explaining how individual agents purposefully act with the goal of managing the value of their information sets. Agents undertake a process of private accumulation of information, which takes into account the non-rival nature of this peculiar entity. Non rivalry introduces an externality that might trigger long-term endogenous fluctuations. The dynamics of interaction, namely the possibility of entering or exiting the group to which the individuals belong, wil l determine time trajectories for the information flows that are unique for the specific conditions of interaction that are being considered at a given momentEste artigo apresenta uma estrutura analítica que tem por objetivo explicar como é que os agentes individuais atuam, de modo intencional, com o propósito de gerir o valor da informação que detêm. Os agentes prosseguem um processo de acumulação privada de informação, o qual toma em consideração a natureza não rival desta entidade que detém características específicas. A não rivalidade introduz uma externalidade que pode despoletar flutuações endógenas de longo prazo. A dinâmica de interação, nomeadamente a possibilidade de entrar ou sair do grupo a que os indivíduos pertencem, vai determinar a formação de trajetórias no tempo para os fluxos de informação, as quais são únicas para as condições particulares de interação que estão a ser consideradas num determinado momento.

The social value of health programs: Is age a relevant factor?

In cost-effectiveness analysis (CEA) it is usually assumed that a QALY is of equal value to everybody, irrespective of the patient's age. However, it is possible that society assigns different social values to a QALY according to who gets it. In this paper we discuss the possibility of weighting health benefits for age in CEA. We also examinethe possibility that age-related preferences depend on the size of the health gain. An experiment was performedto test these hypotheses. The results assessing suggest that the patient's age is a relevant factor when assessing health gains.

How to recognize opportunities: Heterarchical search in a Wall Street trading room

Our task in this paper is to analyze the organization of trading in the era of quantitativefinance. To do so, we conduct an ethnography of arbitrage, the trading strategy that bestexemplifies finance in the wake of the quantitative revolution. In contrast to value andmomentum investing, we argue, arbitrage involves an art of association - the constructionof equivalence (comparability) of properties across different assets. In place of essentialor relationa l characteristics, the peculiar valuation that takes place in arbitrage is based on an operation that makes something the measure of something else - associating securities to each other. The process of recognizing opportunities and the practices of making novel associations are shaped by the specific socio-spatial and socio-technical configurations of the trading room. Calculation is distributed across persons and instruments as the trading room organizes interaction among diverse principles of valuation.