8,837 research outputs found

    Temporal and spatial distribution of stratospheric trace gases over Antarctica in August and September, 1987

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    There have been a large number of suggestions made concerning the origin of the Antarctic 'ozone hole' since its discovery; these changes include stratospheric chemistry, or changes in the solar input, or combinations of these effects. Supporting or refuting these theories requires a wide variety of data for comparison with the predictions. In Aug. and Sept., 1987, a field observation expedition was made over Antarctica from a base in Punta Arenas, Chile. Two aircraft, an ER-2 with in-situ instruments flew at altitudes up to 18 km measuring ozone, water, ClO, BrO, NO sub x, particles, and meteorological parameters in the ozone layer. A DC-8 flew at altitudes of 10 to 12 km, below the ozone layer, using remote sensing instruments for measuring composition and aerosol content of the ozone layer, as well as in-situ instruments for measuring composition at aircraft altitudes. The obsevation of a number of chemical species and their correlation with each other and with meteorological parameters gives a useful set of data for comparison with various theories

    Infrared measurements of column amounts of stratospheric constituents in the Antarctic winter, 1987

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    The discovery of Farman et al. of recent large depletions of ozone in the Antarctic stratosphere in the austral spring has aroused great interest because of its serious potential consequences, as well as its surprising nature. An airborne expedition, including 21 experiments on two aircraft, was mounted for Punta Arenas, Chile, in August and September, 1987, to gather a wide range of data to understand the origins and implications of this phenomenon, known as the ozone hole. As a part of this expedition, a high resolution Fourier transform spectrometer was flown on the DC-8, measuring the column amount of a number of trace gases above the flight altitude. Column results are presented only from the flight of September 21; results from other flights are included in an accompanying paper. The deduced column for ozone HCl, and NO2 deduced from the spectra, plotted as a function of latitude are shown. It should be noted that there are many other factors varying as well as the latitude, but latitude seems to be the variable which most clearly provides a passage across the vortex boundary. It can be seen that south 76 degrees S., the column of ozone, HCl, and NO2, all decreas markedly, The ratio of HCl to Hf, normally about 5:1 in midlatitudes, approaches unity. Clearly the chemistry of chlorine and nitrogen are disturbed in the region of low ozone. While dynamical theories could perhaps explain a reduction of these three gases in the same region, since all are of stratospheric origin, it is difficult to see how any purely dynamical mechanism could produce the observed HCl:HF ratio, since the two gases have similar origins. A close look at other species to be reported as well as the correlation with other measurements, such as ClO supports the conclusion that the ozone depletion is a result of chemical processes which deplete HCl and NOx relative to the midlatitude situation

    Barriers & facilitators to extended working life : a focus on a predominately female ageing workforce

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    Many countries are reforming their pension systems so people stay in work for longer to improve the long-term sustainability of public finances to support an increasing older population. This research aimed to explore the factors that enable or inhibit people to extend working life (EWL) in a large UK based retail organisation. Semi-structured interviews were carried out with a purposive sample (n=30): 15 employees aged ≥ 60 and 15 supervisors supporting these employees. Older workers were predominately female, reflecting the gender profile of the older workers in the organisation. Older workers and supervisors reported that key facilitators to EWL were: good health, the perception that older workers are of value; flexibility and choice; the need for an ongoing conversation across the life-course; the social and community aspect of work as a facilitator to EWL; and, the financial necessity to EWL. Perceived barriers to EWL included poor health, negative impacts of work on health, and a lack of respect and support

    NONPARAMETRIC ESTIMATION OF MULTIPRODUCT AND PRODUCT-SPECIFIC ECONOMIES OF SCALE

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    Numerous studies have utilized nonparametric estimation of production efficiency but no such study focuses on multiproduct or product-specific economies of scale. A mathematical program is specified to nonparametrically estimate these measures for crops and livestock for Kansas farms. Results show that many farms would realize benefits from expansion.Industrial Organization,
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