164 research outputs found

    Physical weathering by glaciers enhances silicon mobilisation and isotopic fractionation

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    Glacial meltwaters export substantial quantities of dissolved and dissolvable amorphous silicon (DSi and ASi), providing an essential nutrient for downstream diatoms. Evidence suggests that glacially exported DSi is isotopically light compared to DSi in non-glaciated rivers. However, the isotopic fractionation mechanisms are not well constrained, indicating an important gap in our understanding of processes in the global Si cycle. We use rock crushing experiments to mimic subglacial physical erosion, to provide insight into subglacial isotope fractionation. Isotopically light DSi (ÎŽ30SiDSi) released following initial dissolution of freshly ground mineral surfaces (down to −2.12 ± 0.02 ‰) suggests mechanochemical reactions induce isotopic fractionation, explaining the low ÎŽ30SiDSi composition of subglacial runoff. ASi with a consistent isotopic composition is present in all mechanically weathered samples, but concentrations are elevated in samples that have undergone more intense physical grinding. These experiments illustrate the critical role of physical processes in driving isotopic fractionation and biogeochemical weathering in subglacial environments. Understanding perturbations in high latitude Si cycling under climatic change will likely depend on the response of mechanochemical weathering to increased glacial melt

    International trade agreements and international migration

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    Despite large potential economic gains to the countries concerned, bilateral and multilateral negotiations regarding liberalization of migration have not had the high profile of trade negotiations and agreements. Migration and trade have been traditionally the prerogative of different ministries, yet there are many interdependencies between international trade, foreign investment and migration. The relevance of these interdependencies for trade negotiations has been remarkably ignored in the literature. In this paper we therefore focus on the two-way interaction between international migration and agreements designed to enhance cross-border trade or investment. Liberalization of international trade in services and the movement of people are likely to offer much more significant economic gains than liberalization of remaining barriers to goods trade. However, progress within multilateral frameworks is fraught with difficulty. Mode IV of GATS is restricted to temporary movement of service employees and has yielded little progress so far. Negotiations within more flexible unilateral and bilateral frameworks are likely to be more successful in liberalizing the movement of labour. We discuss several specific examples and conclude that trade negotiations are increasingly accommodating migration policies that favour temporary migration over permanent migration and that the migration regulatory framework is likely to be further linked to trade and investment over time

    Projected risks to groundwater-dependent terrestrial vegetation caused by changing climate and groundwater abstraction in the Central Perth Basin, Western Australia

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    The effect of potential climate change on groundwater-dependent vegetation largely depends on the nature of the climate change (drying or wetting) and the level of current ecosystem dependence on groundwater resources. In south-western Australia, climate projections suggest a high likelihood of a warmer and drier climate. The paper examines the potential environmental impacts by 2030 at the regional scale on groundwater-dependent terrestrial vegetation (GDTV) adapted to various watertable depths, on the basis of the combined consideration of groundwater modelling results and the framework for GDTV risk assessment. The methodology was tested for the historical period from 1984 to 2007, allowing validation of the groundwater model results\u27 applicability to such an assessment. Climate change effects on GDTV were evaluated using nine global climate models under three greenhouse gas emission scenarios by applying the climate projections to groundwater models. It was estimated that under dry climate scenarios, GDTV is likely to be under high and severe risk over more than 20% of its current habitat area. The risk is also likely to be higher under an increase in groundwater abstraction above current volumes. The significance of climate change risk varied across the region, depending on both the intensity of the change in water regime and the sensitivity of the GDTV to such change. Greater effects were projected for terrestrial vegetation dependent on deeper groundwater (6-10m)

    Silicon isotopes highlight the role of glaciated fjords in modifying coastal waters

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    Glaciers and ice sheets are experiencing rapid warming under current climatic change and there is increasing evidence that glacial meltwaters provide key dissolved and dissolvable amorphous nutrients to downstream ecosystems. However, large debate exists around the fate of these nutrients within complex and heterogenous fjord environments, where biogeochemical cycling is still often poorly understood. We combine silicon (Si) concentration data with isotopic compositions to better understand silicon cycling and export in two contrasting fjordic environments in south-west Greenland. We show that both fjords have isotopically light dissolved silicon (DSi) within surface waters, despite an apparently rapid biological drawdown of DSi with increasing salinity. We hypothesise that such observations cannot be explained by simple water mass mixing processes, and postulate that an isotopically light source of Si, most likely glacially-derived amorphous silica (ASi), is responsible for further modifying these coastal waters within the fjords and beyond. Fjord to coastal exchange is likely a relatively slow process (several months), and thus is less impacted by short-term (< seasonal) changes of glacial meltwater input into the fjord, which has implications when considering the role of glacial meltwaters on nutrient export beyond the shelf break. We highlight the need for isotopic studies combined with dissolved and particulate nutrient concentration analysis to provide a more detailed analysis into the biogeochemical cycles within these highly dynamic fjord environments

    A review of the academic and psychological impact of the transition to secondary education

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    The transition from primary to secondary education is one of the most stressful events in a young person’s life (Zeedyk et al., 2003) and can have a negative impact on psychological wellbeing and academic achievement. One explanation for these negative impacts is that the transition coincides with early adolescence, a period during which certain psychological disorders (i.e., anxiety disorders) become more salient (Kessler et al., 2005) and marked social, biological, and psychological development occurs (Anderson, Jacobs, Schramm, & Splittgerber, 2000). This review evaluates the existing literature on the psychological and academic impacts of the transition to secondary education on young adolescents. We examine the factors that plausibly increase or mitigate the risk of developing mental health issues and/or a decline in academic performance during the transition to secondary education. We also review the interplay between psychological health and academic achievement across and beyond the transition. We conclude with a summary of what schools and parents can learn from these findings to support children in a successful transition into secondary education

    Deciphering splenic marginal zone lymphoma pathogenesis: the proposed role of microRNA

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    Splenic marginal zone lymphoma (SMZL) is a malignancy of mature B-cells that primarily involves the spleen, but can affect peripheral organs as well. Even though SMZL is overall considered an indolent malignancy, the majority of cases will eventually progress to be more aggressive. In recent years, the gene expression profile of SMZL has been characterized in an effort to identify: 1) the etiology of SMZL, 2) biological consequences of SMZL, and 3) putative therapeutic targets. However, due to the vast heterogeneity of the malignancy, no conclusive target(s) have been deciphered. However, the role of miRNA in SMZL, much as it has in chronic lymphocytic leukemia, may serve as a guiding light. As a result, we review the comprehensive expression profiling in SMZL to-date, as well as describe the miRNA (and potential mechanistic roles) that may play a role in SMZL transformation, particularly within the 7q region

    The Rehabilitation Effectiveness for Activities for Life (REAL) study: a national programme of research into NHS inpatient mental health rehabilitation services across England

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    Background: The REAL (Rehabilitation Effectiveness for Activities for Life) research programme, funded by the National Institute for Heath Research (NIHR) from 2009 to 2015, investigated NHS mental health rehabiliation services across England. The users of these services are people with longer-term, complex mental health problems, such as schizophrenia, who have additional problems that complicate recovery. Although only around 10% of people with severe mental illness require inpatient rehabilitation, because of the severity and complexity of their problems they cost 25–50% of the total mental health budget. Despite this, there has been little research to help clinicians and commissioners to plan and deliver effective treatments and services. This research aimed to address this gap. Methods: The programme had four phases. (1) A national survey, using quantitative and qualitative methods, was used to provide a detailed understanding of the scope and quality of NHS mental health rehabilitation services in England and the characteristics of those who use them. (2) We developed a training intervention for staff of NHS inpatient mental health rehabilitation units to facilitate service users’ activities. (3) The clinical effectiveness and cost-effectiveness of the staff training programme was evaluated through a cluster randomised controlled trial involving 40 units that scored below average on our quality assessment tool in the national survey. A qualitative process evaluation and a realistic evaluation were carried out to inform our findings further. (4) A naturalistic cohort study was carried out involving 349 service users of 50 units that scored above average on our quality assessment tool in the national survey, who were followed up over 12 months. Factors associated with better clinical outcomes were investigated through exploratory analyses. Results: Most NHS trusts provided inpatient mental health rehabilitation services. The quality of care provided was higher than that in similar facilities across Europe and was positively associated with service users’ autonomy. Our cluster trial did not find our staff training intervention to be clinically effective [coefficient 1.44, 95% confidence interval (CI) –1.35 to 4.24]; staff appeared to revert to previous practices once the training team left the unit. Our realistic review suggested that greater supervision and senior staff support could help to address this. Over half of the service users in our cohort study were successfully discharged from hospital over 12 months. Factors associated with this were service users’ activity levels [odds ratio (OR) 1.03, 95% CI 1.01 to 1.05] and social skills (OR 1.13, 95% CI 1.04 to 1.24), and the ‘recovery’ orientation of the unit (OR 1.04, 95% CI 1.00 to 1.08), which includes collaborative care planning with service users and holding hope for their progress. Quality of care was not associated with costs of care. A relatively small investment (£67 per service user per month) was required to achieve the improvement in everyday functioning that we found in our cohort study. Conclusions: People who require inpatient mental health rehabilitation are a ‘low-volume, high-needs’ group. Despite this, these services are able to successfully discharge most to the community within 18 months. Our results suggest that this may be facilitated by recovery-orientated practice that promotes service users’ activities and social skills. Further research is needed to identify effective interventions that enhance such practice to deliver these outcomes. Our research provides evidence that NHS inpatient mental health rehabilitation services deliver high-quality care that successfully supports service users with complex needs in their recovery. Main limitation: Our programme included only NHS, non-secure, inpatient mental health rehabilitation services. Trial registration: Current Controlled Trials ISRCTN25898179. Funding: The NIHR Programme Grants for Applied Research programme
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