1,151 research outputs found

    Local Rates of Ice-Sheet Thickness Change in Greenland

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    The rate of ice-sheet thickness change is calculated for 10 sites in Greenland by comparing measured values of ice vertical velocity and snow-accumulation rate. Vertical velocities are derived from repeat surveys of markers using precision global positioning system techniques, and accumulation rates are determined from stratigraphic analysis of firn cores. The results apply to time-scales covered by the firn-core records, which in most cases are a few decades. A spectrum of thickness-change rates is obtained, ranging from substantial thinning to slow thickening. The sites where ice-sheet thinning is indicated are located near the ice-sheet margin or in outlet glacier catchments. Interior and high-elevation sites are predominantly in balance or thickening slowly. Uncertainties in the rates of thickness change are dominated by errors in the determination of accumulation rates. The results of this work are broadly comparable with regional estimates of mass balance obtained from the analysis of catchment input vs discharge

    Individual placement and support for ex-prisoners with mental health problems

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    Employment is often viewed by policymakers as a key factor in the reintegration process for ex-prisoners. This thesis centres around the examination of a specialist employment service, Individual Placement and Support (IPS), for ex-prisoners with mental health difficulties within the criminal justice system (CJS) in England and Wales. Specifically, this thesis seeks to understand what works, for whom, and under what circumstances. The key objectives of the study were to understand how the IPS service operated within the CJS, whether it was successful in achieving competitive employment for ex-prisoners with mental health difficulties, and how it may need to be adapted to improve its efficacy. In order to achieve this, the current study implemented a mixed-methods approach over a one-year timeframe. The recruitment of participants and delivery of the intervention was based within several prisons and across community sites within England. Results indicated that, despite study limitations, IPS was shown to be significantly superior to “service as usual” (SAU) at the six-month follow-up. This indicates that an IPS service may be effective in supporting ex-offenders who have mental health difficulties to obtain competitive employment, if this finding can be replicated in other contexts. This study also found that, rather than triggering desistance from offending behaviour, employment is likely to help maintain desistance. Furthermore, results indicated that analysis of the functionality of crime and employment for each individual may help to explain who benefits from employment in terms of desistance. These findings have implications for policy. Although people who have criminal justice involvement and mental health difficulties express a desire to gain employment, there is a lack of specialist, and consistent, supported employment services for this population. Results of this study highlight how these needs can be met and may contribute to the design and implementation of a future IPS service within the CJS. Specifically, the findings suggest that intensive employment support needs to be fully integrated with a comprehensive approach to reintegration, paying particular attention to criminal functions and other motivating factors for desistance

    Thickness Changes on Whillans Ice Stream and Ice Stream C, West Antarctica, Derived from Laser Altimeter Measurements

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    Repeat airborne laser altimeter measurements are used to derive surface elevation changes on parts of Whillans Ice Stream and Ice Stream C, West Antarctica. Elevation changes are converted to estimates of ice equivalent thickness change using local accumulation rates, surface snow densities and vertical bedrock motions. The surveyed portions of two major tributaries of Whillans Ice Stream are found to be thinning almost uniformly at an average rate of similar to 1 m a(-1). Ice Stream C has a complicated elevation-change pattern, but is generally thickening. These results are used to estimate the contribution of each surveyed region to the current rate of global sea-level rise

    Microwave treatment of electric arc furnace dust with Tetrabromobisphenol A: Dielectric characterization and pyrolysis-leaching

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    In the present work microwave treatment of electric arc furnace dust (EAFD) mixed with tetrabromobisphenol A (TBBPA) was investigated. A range of characterization techniques were used to understand the thermal behaviour of TBBPA-EAFD mixtures under microwave pyrolysis conditions. Dielectric and thermal properties of EAFD, TBBPA and their mixtures were determined. Both the dielectric constant and loss factor of the mixture were found to vary considerably with temperature and subsequently it was found that the mixtures of these materials absorbed microwaves effectively, especially at temperatures above 170 °C. The high loss tangent of EAFD-TBBPA mixture above 170 °C resulted in fast heating and high temperatures (above 700 °C) resulting in reduction of Fe, Pb and Zn to their metallic form. This resulted in low recoveries of both Zn and Pb when the residue was leached in water. The recovery of Zn varied between 14 and 52 wt,%, while Pb recovery varied between 3 and 31 wt.% depending on microwave treatment efficiency. The low recovery of Zn and Pb could be ascribed by the reduction of metal oxides into their metallic form. More importantly this work has shown great selectivity in the leachability of both zinc and iron; with iron being left in the solid residue

    'Ava’: a Beaker-associated woman from a cist at Achavanich, Highland, and the story of her (re-) discovery and subsequent study

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    This contribution describes the discovery and subsequent investigation of a cist in a rock-cut pit at Achavanich, Highland. Discovered and excavated in 1987, the cist was found to contain the tightly contracted skeletal remains of a young woman, accompanied by a Beaker, three flint artefacts and a cattle scapula. Initial post excavation work established a date for the skeleton together with details of her age and sex, and preliminary pollen analysis of sediments attaching to the Beaker was undertaken. The findings were never fully published and, upon the death of the excavator, Robert Gourlay, the documentary archive was left in the Highland Council Archaeology Unit. Fresh research in 2014–17, initiated and co-ordinated by the first-named author and funded by the Society of Antiquaries of Scotland with assistance from National Museums Scotland, the Natural History Museum and Harvard Medical School, has produced a significant amount of new information on the individual and on some of the items with which she was buried. This new information includes two further radiocarbon dates, a more detailed osteological report, isotopic information pertaining to the place where she had been raised and to her diet, histological information on the decomposition of her body, and genetic information that sheds light on her ancestry, her hair, eye and skin colour and her intolerance of lactose. (This is the first time that an ancient DNA report has been published in the Proceedings.) Moreover, a facial reconstruction adds virtual flesh to her bones. The significance of this discovery within the Chalcolithic to Early Bronze Age of this part of Scotland is discussed, along with the many and innovative ways in which information on this individual, dubbed ‘Ava’, has been disseminated around the world.Copyright © 2018 rests with the Society and the individual authors. Except where otherwise noted, this work is licensed under CreativeCommons Attribution-NonCommercial-No Derivatives licence.https://creativecommons.org/licenses/by-nc-nd/4.0/ The permission to reproduce the Society's copyright-protected ma-terial does not extend to any material which is identified as being the copyright of a third party. Authorisation to reproduce such material must be obtained from the copyright holders concerned. The attached file is the published pdf

    Emergent sustainability in open property regimes

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    Current theoretical models of the commons assert that common-pool resources can only be managed sustainably with clearly defined boundaries around both communities and the resources that they use. In these theoretical models, open access inevitably leads to a tragedy of the commons. However, in many open-access systems, use of common-pool resources seems to be sustainable over the long term (i.e., current resource use does not threaten use of common-pool resources for future generations). Here, we outline the conditions that support sustainable resource use in open property regimes. We use the conceptual framework of complex adaptive systems to explain how processes within and couplings between human and natural systems can lead to the emergence of efficient, equitable, and sustainable resource use. We illustrate these dynamics in eight case studies of different social–ecological systems, including mobile pastoralism, marine and freshwater fisheries, swidden agriculture, and desert foraging. Our theoretical framework identifies eight conditions that are critical for the emergence of sustainable use of common-pool resources in open property regimes. In addition, we explain how changes in boundary conditions may push open property regimes to either common property regimes or a tragedy of the commons. Our theoretical model of emergent sustainability helps us to understand the diversity and dynamics of property regimes across a wide range of social–ecological systems and explains the enigma of open access without a tragedy. We recommend that policy interventions in such self-organizing systems should focus on managing the conditions that are critical for the emergence and persistence of sustainability
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