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981.
David P. Ellerman 《Metroeconomica》1990,41(3):259-276
The paper mathematically develops the heuristic idea that the first-order necessary conditions for a classical constrained optimization problem are equivalent to a market being arbitrage-free - with the Lagrange multipliers being the arbitrage-free market prices. The arbitrage notions start with the multiplicative Kirchhoff's Voltage Law and then generalize to matrix algebra. The basic result shows the normalized arbitrage-free «market prices» (the Lagrange multipliers) resulting from a classical constrained optimizaton problem can always be obtained as a ratio of cofactors. The machinery also gives an economic interpretation of Cramer's Rule as a competitive equilibrium condition. 相似文献
982.
C. James Dahn 《Process Safety Progress》1992,11(3):201-204
The potential for dust explosion from electrostatic discharge in pneumatic Conveying systems has been reviewed. The importance of lab testing to determine electrostatic charging of powders in contact with materials of construction is illustrated. Correlation of predicted voltage fields (from lab testing) to full scale is good. With the voltage field information, ESD potential at various parts of the pneumatic conveying system can be determined (primarily in receivers, silo and separator). 相似文献
983.
Tom P. Moorhouse Neil C. D’Cruze David W. Macdonald 《Journal of Sustainable Tourism》2019,27(1):12-33
Many wildlife tourist attractions (WTAs) have negative impacts on animal welfare and species conservation. In the absence of regulation, raising standards requires tourists to create market pressure by choosing to attend WTAs with benefits for wildlife. We surveyed respondents from five countries – China, Australia, Canada, UK, and USA – to quantify how attitudes to captive animals, and towards WTAs’ outputs and standards, may vary with nationality. Our aim was to provide a firm basis for behaviour change interventions to alter current patterns of tourist consumption of WTAs. All respondents agreed on the importance of conservation and animal welfare, but Chinese respondents were twice as likely to believe that WTAs would not be allowed to exist if they were bad for animals, and that WTAs’ promotional materials were reliable indicators of welfare and conservation standards. These findings indicate Chinese respondents had fundamentally similar attitudes to those from the other countries, but differed in how those attitudes were likely to be applied. Chinese tourists may experience more barriers to aligning their actions with their values with respect to WTAs. Removing these barriers may require information campaigns to highlight the lack of regulation, and the unreliability of some WTAs’ promotional materials and tourists’ reviews. 相似文献
984.
Great hopes have been placed in the sharing economy to provide a new business model based on peer-to-peer (P2P) exchanges of underutilized assets. As a model, the sharing economy has been expected to make significant contributions to sustainability, providing new opportunities for entrepreneurship, more sustainable use of resources, and consumer co-operation in tight economic networks. However, in recent years, digital platforms have turned into the most important actors in the global sharing economy, turning global corporations, such as AirBnB, Booking, or TripAdvisor into intermediaries controlling and profiting from most transactions. Focused on accommodation, this paper conceptualizes the sharing economy in comparison to the wider collaborative economy, and discusses its social, economic, environmental, and political impacts in comparison to the sustainable development goals. It concludes that the sharing economy has great potential to make very significant contributions to sustainability, though the model is increasingly being replaced by the collaborative economy, which performs as an extension and acceleration of neoliberal economic practices. 相似文献
985.
986.
The purpose of this study was to develop an instrument to measure adult awareness of consumer product/service information sources, consumer protection laws and channels of recourse. The process included identification of prevalent consumer problems, development of test items based on the identified problems, and assessments of the content validity and the reliability of the instrument. The process of construct validity was initiated by developing and testing hypotheses concerning the relationships between scores on the instrument and selected socio-economic characteristics of consumers. Low consumer awareness scores were predominant, supporting the need for consumer education for adults. 相似文献
987.
988.
The hypothesis of induced innovation is tested for U.S. agriculture using a high-quality state-level panel data set and three disparate testing techniques—time series, direct econometric, and nonparametric. We find little support for the hypothesis. That conclusion is robust across testing techniques. However, as with all empirical tests of this hypothesis conducted to date, ours focus only on the demand side of the hypothesis. The hypothesis could have been rejected simply because the marginal cost of developing and implementing input-saving technologies for the relatively expensive inputs is greater than for the relatively cheap inputs. 相似文献
989.
The future demand for land for mining and quarrying will be affected by a large number of economic, technological, environmental and social issues within the UK. Global developments also have a role to play. Although mining and quarrying account for only 0.9 per cent of the land area of England, the impact of this activity is considerable. Minerals are essential to the economy, for energy, construction, infrastructure and manufacturing, while their extraction has effects on the environment and on public perception. This paper examines current scientific understanding of the context of mining and quarrying, with particular reference to its impact on land use, along with the spatial relationship between minerals – which can only be worked where they occur – and other forms of land use and designation in the ‘post-industrial’ landscape of Britain. Looking out to 2060 and beyond, developments which may influence demand for minerals include climate change mitigation and adaptation; energy, food and raw material security; and new construction, manufacturing, recycling and re-use technologies. Factors influencing the supply side include the structure and ownership of the mining and quarrying industry, new extraction, processing and environmental technologies, ecosystem service provision, societal attitudes and land access. Although prediction carries a high level of uncertainty, continuous development of the regulatory framework is, and will remain, a major and pervasive factor in the relationship between mining and quarrying and land use. 相似文献
990.
Carlos Parra-Lpez Jeroen C.J. Groot Carmen Carmona-Torres Walter A.H. Rossing 《Land use policy》2009,26(4):1020-1030
An integrated methodological framework for ex-ante evaluation and planning of public policies for sustainable agriculture at agro-landscape level is proposed. The components of the framework are to: (1) determine the private, i.e. farmers’, and public benefits associated to agro-landscapes, consisting of an agricultural land-use system, according to its performance for several market and non-market functions. Market forces determine the market benefits and preferences of society the non-market benefits; (2) explore and select potential sustainable agro-landscapes based on the private and public benefits associated with possible land-use alternatives; (3) define efficient public policy mechanisms for improving social net benefit of agro-landscapes.The framework is illustrated with a case study in a small dairy farming dominated agro-landscape in The Netherlands, with gross margin, landscape quality, nature value and environmental health as the analysed ecosystem functions. Alternative landscapes consisting of hedgerow configurations and grassland management practices were explored, yielding a set of alternatives representing the solution space in terms of change in private and public benefits. Policy mechanisms were defined to move from the current to a desired landscape based on changes in social net benefits. Moreover, the necessity of a modification in the current agri-environmental support was analysed for each landscape. The analysis considered all farmers in the agro-landscape jointly. The results for the case study showed potential prototypes of landscapes and their performance compared to the current landscape. Extension was the most efficient policy mechanism to promote the change to the socially optimum landscape alternative. 相似文献