1,085 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

    Cross-cultural effects of color, but not morphological masculinity, on perceived attractiveness of men's faces

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    This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 ElsevierMuch attractiveness research has focused on face shape. The role of masculinity (which for adults is thought to be a relatively stable shape cue to developmental testosterone levels) in male facial attractiveness has been examined, with mixed results. Recent work on the perception of skin color (a more variable cue to current health status) indicates that increased skin redness, yellowness, and lightness enhance apparent health. It has been suggested that stable cues such as masculinity may be less important to attractiveness judgments than short-term, more variable health cues. We examined associations between male facial attractiveness, masculinity, and skin color in African and Caucasian populations. Masculinity was not found to be associated with attractiveness in either ethnic group. However, skin color was found to be an important predictor of attractiveness judgments, particularly for own-ethnicity faces. Our results suggest that more plastic health cues, such as skin color, are more important than developmental cues such as masculinity. Further, unfamiliarity with natural skin color variation in other ethnic groups may limit observers' ability to utilize these color cues

    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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