12,284 research outputs found

    Chemiluminescence of asbestos-activated macrophages

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    Chemiluminescence, a measure of reactive oxygen release by phagocytes, was compared in peritoneal exudate macrophages elicited with chrysotile asbestos, Corynebacterium parvum and saline. Chrysotile asbestos- and C. parvum-activated macrophages produced significantly more chemiluminescence than saline-elicited macrophages. In a second series of experiments the ability of opsonized chrysotile asbestos to act as a trigger for the release of chemiluminescence was tested. Opsonized chrysotile asbestos produced a dose-related release of chemiluminescence from activated macrophages except at the highest dose where chemiluminescence was reduced due, possibly, to a toxic effect of chrysotile during the assay. Opsonized latex also triggered a dose-related chemiluminescent response from activated macrophages. The potential role of toxic reactive oxygen species, released from macrophages, in the development of asbestos-related pulmonary inflammation and fibrosis are discussed

    Forestry policy and poverty: the case of community forestry in Nepal

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    Common forests in developing countries are valuable sources of raw material supplies, employment and income generation, particularly for low income households. This paper looks at the effect on income and employment when common forest resources have external policies that constrain their use. Using a mixed-integer linear programming model, this study examines the impacts of conservation-oriented community forest policies in Nepal on three household income groups. The results show that current community forest policies, which focus on environmental outcomes through forest use restriction for environment conservation and timber production, result in a large reduction in employment and income of the poorest households and largely explain the recent increase in poverty of rural areas.Forestry policy, poverty, Nepal, Agricultural and Food Policy, Community/Rural/Urban Development, Crop Production/Industries, Environmental Economics and Policy, Farm Management, Land Economics/Use, Resource /Energy Economics and Policy,

    Factors influencing adoption of agroforestry among smallholder farmers in Zambia

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    Agroforestry technologies have been extensively researched and introduced to smallholder farmers in Zambia for over two decades. Despite the research and extension effort over this period, not many farmers have adopted these technologies. The purpose of this paper is to determine why agroforestry technologies are not being taken up by examining factors that influence the adoption of agroforestry practices. Based on data obtained from 388 farming households, statistical analysis show an association between adoption of both improved fallows and biomass transfer technologies with knowledge of the technology, availability of seed, and having the appropriate skills. In addition some household characteristics are found to be linked to the incidence of adoption. However, the strength of association between these variables is low, giving an indication that there might be other factors at play limiting agroforestry adoption. It is anticipated that these findings will point to other areas beyond the household and community level that need further exploration in order to understand factors limiting agroforestry adoption.Agroforestry adoption, smallholder farmers, limitations to adoption, chi-square tests of independence analysis, Zambia, Agricultural and Food Policy, Community/Rural/Urban Development, Crop Production/Industries, Environmental Economics and Policy, Land Economics/Use,

    Alternative to Comprehensive Ecosystem Services Markets: The Contribution of Forest-Related Programs in New Zealand

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    Due to the public goods characteristics of many ecosystem services and their vital importance to human welfare, various mechanisms have been put in place to motivate private landowners in the provision of ecosystem services. A common approach is to try to develop a comprehensive ecosystem services market where landowners can receive payments from beneficiaries of ecosystem services. Much research has been directed at developing methods for valuing the range of ecosystem services so that they can be incorporated into ecosystem services markets. However, valuation methods are difficult, expensive and time consuming. Other approaches to the provision of ecosystem services such as payments for ecosystem services usually focus on a single service like water or biodiversity. However, in the provision of a particular ecosystem service, there are spill-over effects of providing other ecosystem services, and thus studying those spill-over effects may provide a simple and cost-effective way of ensuring the provision of a wide range of ecosystem services. In New Zealand, there are a variety of forestry programs which provide incentives to landowners to plant trees on their lands to meet particular objectives, but which also produce other ES. This research aims to evaluate the cost-effectiveness of the provision of a wide range of ES by these approaches, the New Zealand Emissions Trading Scheme, the East Coast Forestry Scheme, and the QEII National Trust.ecosystem services market, spill-over effect, cost-effectiveness, New Zealand, Environmental Economics and Policy,

    Potential of Forest Resources to Alleviate Poverty and Unemployment in Rural Nepal

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    The study examines the importance of community forest resources for income and employment in rural areas of Nepal by studying the effect of current forestry policy on forestland use. Using data from 259 households in six community forest user groups in three hilly districts (Dolakha, Kavre and Nuwakot), the results show that the resources available from private lands and community forests with current policies are inadequate to fully utilize the family labour force of many rural households and are insufficient to meet the bare survival income of the poorest households. Current government policy dictates the use of all community forestland for limited timber production and environmental conservation, and provides little scope for fodder and firewood production. The study shows that community forestland management with an agroforestry model could overcome rural unemployment problems and increase incomes.Community welfare model, livelihood, community forestry, incomes, Community/Rural/Urban Development, Consumer/Household Economics, Food Security and Poverty, Labor and Human Capital, Resource /Energy Economics and Policy,

    The Close Binary Fraction of Dwarf M Stars

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    We describe a search for close spectroscopic dwarf M star binaries using data from the Sloan Digital Sky Survey to address the question of the rate of occurrence of multiplicity in M dwarfs. We use a template-fitting technique to measure radial velocities from 145,888 individual spectra obtained for a magnitude-limited sample of 39,543 M dwarfs. Typically, the three or four spectra observed for each star are separated in time by less than four hours, but for ~17% of the stars, the individual observations span more than two days. In these cases we are sensitive to large-amplitude radial velocity variations on timescales comparable to the separation between the observations. We use a control sample of objects having observations taken within a four-hour period to make an empirical estimate of the underlying radial velocity error distribution and simulate our detection efficiency for a wide range of binary star systems. We find the frequency of binaries among the dwarf M stars with a < 0.4 AU to be 3%-4%. Comparison with other samples of binary stars demonstrates that the close binary fraction, like the total binary fraction, is an increasing function of primary mass

    Valuing agricultural externalities in Canterbury rivers and streams

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    Water quality and quantity concerns in Canterbury are intrinsically related to agriculture. Monetary values for impacts on streams and rivers is lacking in policy debate. This paper employs choice modelling to estimate values of three impacts on rivers and streams in Canterbury associated with agriculture: health risks of E coli from animal waste, ecological effects of excess nutrients, and low-flow impacts of irrigation. This study provides a valuation of outcomes for public policy implemented in Canterbury such as The Dairy and Clean Streams Accord, Living Streams, and The Restorative Programme for Lowland Streams.non-market-valuation, choice experiment, agricultural externalities, New Zealand, Agricultural and Food Policy, Environmental Economics and Policy, Food Consumption/Nutrition/Food Safety, Health Economics and Policy,

    How to design a proper 'executive information support system'

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