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301.
302.
The demographic structure of a country influences economic activity. The “second dividend” modifies growth. Accordingly, in general equilibrium, the second dividend and the demographic structure are interrelated. This paper aims at assessing empirically the “second dividend” in a dynamic, empirical and intertemporal setting that allows for measuring its impact on growth, its intergenerational redistributive effects, and its interaction with the demographic structure. The paper uses a general equilibrium model with overlapping generations, an energy module and a public finance module that distinguishes between non-ageing-related public spending and a pension regime. Policy scenarios compare the consequences of different scenarios of recycling a carbon tax through lower proportional income taxes rather than higher public lump-sum expenditures. They are computed for two countries with different demographics (France and Germany). Results suggest that the magnitude of the “second dividend” is significantly related with the demographic structure. The more concentrated the demographic structure on cohorts with higher income and saving rate, the stronger the effect on capital supply of the second dividend. The second dividend weighs on the welfare of relatively aged working cohorts. It fosters the wellbeing of young working cohorts and of future generations. The more concentrated the demographic structure on aged working cohorts, the higher the intergenerational redistributive effects of the second dividend. 相似文献
303.
Coltan from Central Africa,international trade and implications for any certification 总被引:1,自引:0,他引:1
The exploitation of coltan in Central Africa can be considered a case of conflict minerals due to its nature. Many international organizations and bodies, national governments and private sector organizations seek to address this conflict, in particular via transparency, certification and accountability along the material supply chain. This paper analyses the international trade dimension of coltan and gives evidence on the dimension of illicit trade of coltan. The authors start from the hypothesis that illicit trade of coltan sooner or later will enter the market and will be reflected in the statistics. The paper is structured in the following manner: first, a short section gives a profile of coltan production and markets; second, an overview of the mining situation in the Democratic Republic of Congo (DRC) and related actors. The third section addresses mechanisms, actors and measurement issues involved in the international trade of coltan. The final part draws lessons for certification and conflict analysis and offers some guidance for future research. 相似文献
304.
I. Vallés A. CamachoX. Ortega I. SerranoS. Blázquez S. Pérez 《Journal of environmental radioactivity》2009
Results for naturally occurring 7Be, 210Pb, 40K, 214Bi, 214Pb, 212Pb, 228Ac and 208Tl and anthropogenic 137Cs in airborne particulate matter in the Barcelona area during the period from January 2001 to December 2005 are presented and discussed. The 212Pb and 208Tl, 214Bi and 214Pb, 7Be and 210Pb radionuclide levels showed a significant correlation with each other, with correlation coefficients of 0.99, 0.78 and 0.69, respectively, suggesting similar origin/behaviour of these radionuclides in the air. Caessium-137 and Potassium-40 were transported to the air as resuspended particle from the soil. The 7Be and 210Pb concentrations showed similar seasonal variations, with a tendency for maximum concentrations during the summer months. An inverse relationship was observed between the 7Be, 210Pb, 40K and 137Cs concentrations and weekly rainfall, indicating washout of atmospheric aerosols carrying these radionuclides. 相似文献
305.
Siak Kuan Lee Husin Wagiran Ahmad Termizi Ramli Nursama Heru Apriantoro A. Khalik Wood 《Journal of environmental radioactivity》2009
Natural background gamma radiation and radioactivity concentrations were investigated from 2003 to 2005 in Kinta District, Perak, Malaysia. Sample locations were distant from any ‘amang’ processing plants. The external gamma dose rates ranged from 39 to 1039 nGy h−1. The mean external gamma dose rate was 222 ± 191 nGy h−1. Small areas of relatively enhanced activity were located having external gamma dose rates of up to 1039 ± 104 nGy h−1. The activity concentrations of 238U, 232Th and 40K were analyzed by using a high-resolution co-axial HPGe detector system. The activity concentration ranges were 12–426 Bq kg−1 for 238U, 19–1377 Bq kg−1 for 232Th and <19–2204 Bq kg−1 for 40 K. Based on the radioactivity levels determined, the gamma-absorbed dose rates in air at 1 m above the ground were calculated. The calculated dose rates and measured dose rates had a good correlation coefficient, R of 0.94. To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the gamma-absorbed dose rate and the mean population weighted dose rate were calculated. An isodose map for the Kinta District was also produced. 相似文献
306.
Gerosa G Finco A Mereu S Vitale M Manes F Denti AB 《Environmental pollution (Barking, Essex : 1987)》2009,157(5):1737-1744
Ozone and energy fluxes have been measured using the eddy covariance technique, from June to December 2004 in Castelporziano near Rome (Italy), and compared to similar measurements made in the previous year. The studied ecosystem consisted in a typical Mediterranean Holm oak forest. Stomatal fluxes have been calculated using the resistance analogy and by inverting the Penmann-Monteith equation. Results showed that the average stomatal contribution accounts for 42.6% of the total fluxes. Non-stomatal deposition proved to be enhanced by increasing leaf wetness and air humidity during the autumnal months. From a comparison of the two years, it can be inferred that water supply is the most important limiting factor for ozone uptake and that prolonged droughts alter significantly the stomatal conductance, even 2 months after the soil water content is replenished. Ozone exposure, expressed as AOT40, behaves similarly to the cumulated stomatal flux in dry conditions whereas a different behaviour for the two indices appears in wet autumnal conditions. A difference also occurs between the two years. 相似文献
307.
Jerzy W. Mietelski Sergiy Dubchak Teresa Anielska 《Journal of environmental radioactivity》2010,101(9):706-711
Fruiting bodies of fungi belonging to more than 70 species were collected within a few thousand square meter area of one forest during 2006 and 2007. The soil profile was collected to check the cumulative deposition of 137Cs, which was relatively high, equal to 64 ± 2 kBq/m2 (calculated for October 2006). The majority of this activity was in the first 6 cm. Fruitbodies were analyzed for radiocesium and 40K by means of gamma-spectrometry. The highest 137Cs activity was 54.1 ± 0.7 kBq/kg (dry weight) for a sample of Lactarius helvus collected in 2006. The results for 2006 were higher than those for 2007. In a few cases the traces of short-lived (T1/2 = 2.06 a) 134Cs were still found in samples. The importance of mycorrhizal fungi for radiocesium accumulation is confirmed. The differences in activity among the species are discussed in relation to observations and predictions from previous studies, where the change in relative accumulation between fruiting bodies of different species was at least partially explained by the differences in the depth of the mycelium localization in a litter/soil system. It is concluded that in some cases, such as Boletus edulis and Xerocomus badius, this prediction is fulfilled and therefore this explanation confirmed. 相似文献
308.
The global gold market has recently attracted a lot of attention and the price of gold is relatively higher than its historical trend. For mining companies to mitigate risk and uncertainty in gold price fluctuations, make hedging, future investment and evaluation decisions, depend on forecasting future price trends. The first section of this paper reviews the world gold market and the historical trend of gold prices from January 1968 to December 2008. This is followed by an investigation into the relationship between gold price and other key influencing variables, such as oil price and global inflation over the last 40 years. The second section applies a modified econometric version of the long-term trend reverting jump and dip diffusion model for forecasting natural-resource commodity prices. This method addresses the deficiencies of previous models, such as jumps and dips as parameters and unit root test for long-term trends. The model proposes that historical data of mineral commodities have three terms to demonstrate fluctuation of prices: a long-term trend reversion component, a diffusion component and a jump or dip component. The model calculates each term individually to estimate future prices of mineral commodities. The study validates the model and estimates the gold price for the next 10 years, based on monthly historical data of nominal gold price. 相似文献
309.
Minerals policy in Europe: Some recent developments 总被引:1,自引:0,他引:1
The importance of a secured supply of raw materials for the European economy is evident. However, securing the supply of raw materials based on an appropriate EU minerals policy has been scarcely treated by the decision-makers in the last decades. Solely the impact of price development of international commodity markets in the last years induces a re-thinking of this field. The EU Raw Materials Initiative, which was published by the European Commission in November 2008, establishes an EU raw materials strategy including a list of actions. 相似文献
310.
The metals boom that ran from 2003 to 2008 represented the most powerful and sustained such boom since the Second World War. As the boom gathered momentum, the notion began to emerge that commodities were at the beginning of a multi-year ‘super cycle’ driven by demand growth in the emerging economies and, in particular, China. The persistence of the boom helped sustain this belief right up to the point when metal prices collapsed in the second half of 2008. Looking back over the period, much of what occurred can be readily explained by the unusual strength of the demand shock and the lagged response of the supplying industry, with prices receiving an additional boost from the activities of commodity investors. There is, however, some evidence to suggest that the combination of downward pressure on the costs of manufactured goods and upward pressure on the costs of mineral commodities which accompanied the boom marked a shift in the terms of trade between these two product groups. This in turn seems to have brought to an end the sustained decline in real terms metal prices that occurred in the years following the boom of the 1970s. In sum, the key structural change taking place may not have been on the demand side of the industry as the super cyclists maintained, but on the supply side. 相似文献