235 resultados para Non-smooth functions
Resumo:
Reports on results of a survey, completed in 2000, of wives in three villages in the Phulbani district, Orissa, India. These villages are dominated by the Kondh scheduled tribe but some also contain members of the scheduled caste, called Dombs in Orissa. The article reports on the total responses and comparative responses of these groups to a structured questionnaire. The article provides background information for the villages surveyed, and reports information in relation to wives and their families about property rights, assets and incomes, economic conditions and survival strategies, aspects of credit, production and marketing, social dynamics and eduction. In addition, children’s affairs, including the treatment and entitlements of female and male children, are considered as well as additional aspects of the socioeconomic status of wives.
Resumo:
The contingent valuation method is often used for valuing environmental goods possessing use as well as non-use values. This paper investigates the relative importance of these values in relation to the existence of the wild Asian elephant. It does so by analysing results from a contingent valuation survey of a sample of urban residents living in three selected housing schemes in Colombo. We find that the major proportion of the respondents’ willingness to pay (WTP) for conservation of wild elephants is attributable to the non-use values of the elephant. However, differences in the relative importance of these values exist between those who visit national parks and those who do not. Differences in respondents’ WTP for conservation of elephants are found to be largely influenced by attitudinal and behavioural factors rather than socio-economic ones. We conclude that policymakers must recognise and take account of the importance of non-use values of the Asian elephant, if this endangered species is to survive in the long run. Nevertheless, the non-consumptive use value of elephants in Sri Lanka is also found to be substantial.
Resumo:
In order to reduce the rate of human-induced biodiversity loss of wild species, it has become increasingly important to stem this loss on private and tribal lands and to find effective policies to do this. Some writers believe that granting landholders commercial property rights in wildlife might be effective in dealing with this matter and result in the sustainable use of wildlife. This paper explores this view using economic theory. In doing so, it takes into account the total economic valuation concept. While granting of commercial property rights is found to be effective for conserving some species, it is predicted to be a complete failure as a means of conserving other species. In addition, particular attention is given to the economics of the utilisation and conservation of non-captive fugitive (or mobile) wildlife. The economic theory involved is contrasted and compared with that for the exploitation of open-access resources.
Resumo:
Cell-surface proteoglycans have been known to be involved in many functions including interactions with components of the extracellular microenvironment, and act as co-receptors which bind and modify the action of various growth factors and cytokines. The purpose of this study was to determine the regulation by growth factors and cytokines on cell-surface proteoglycan gene expression in cultured human periodontal ligament (PDL) cells. Subconfluent, quiescent PDL cells were treated with various concentrations of serum, bFGF, PDGF-BB, TGF-beta1, IL-1 beta, and IFN-gamma. RT-PCR technique was used, complemented with Northern blot for syndecan-1, to examine the effects of these agents on the mRNA expression of five cell-surface proteoglycans (syndecan-1, syndecan-2, syndecan-4, glypican and betaglycan). Syndecan-1 mRNA levels increased in response to serum, bFGF and PDGF-BB, but decreased in response to TGF-beta1, IL-1 beta and IFN-gamma. In contrast, syndecan-2 mRNA levels were upregulated by TCF-beta1 and IL-1 beta stimulation, but remained unchanged with the other agents. Betaglycan gene expression decreased in response to serum, but was upregulated by TCF-beta1 and unchanged by the other stimulants. Additionally, syndecan-4 and glypican were not significantly altered in response to the regulator molecules studied, with the exception that glypican is decreased in response to IFN-gamma. These data demonstrate that the gene expression of the five cell-surface proteoglycans studied is differentially regulated in PDL cells lending support to the nation of distinct functions for these cell-surface proteoglycans. (C) 2001 Wiley-Liss, inc.
Resumo:
Non-periodic structural variation has been found in the high T-c cuprates, YBa2Cu3O7-x and Hg0.67Pb0.33Ba2Ca2Cu3O8+delta, by image analysis of high resolution transmission electron microscope (HRTEM) images. We use two methods for analysis of the HRTEM images. The first method is a means for measuring the bending of lattice fringes at twin planes. The second method is a low-pass filter technique which enhances information contained by diffuse-scattered electrons and reveals what appears to be an interference effect between domains of differing lattice parameter in the top and bottom of the thin foil. We believe that these methods of image analysis could be usefully applied to the many thousands of HRTEM images that have been collected by other workers in the high temperature superconductor field. This work provides direct structural evidence for phase separation in high T-c cuprates, and gives support to recent stripes models that have been proposed to explain various angle resolved photoelectron spectroscopy and nuclear magnetic resonance data. We believe that the structural variation is a response to an opening of an electronic solubility gap where holes are not uniformly distributed in the material but are confined to metallic stripes. Optimum doping may occur as a consequence of the diffuse boundaries between stripes which arise from spinodal decomposition. Theoretical ideas about the high T-c cuprates which treat the cuprates as homogeneous may need to be modified in order to take account of this type of structural variation.