395 research outputs found
Slab failure or slab success? Examining the contributions of crust and mantle to post-subduction magmatism in the Ratagain Complex, NW Scotland
The Ratagain Complex is an enigmatic Late Caledonian granitic intrusion and a member of the high Basingle bondSr Northern Highlands granite (NHG) suite that has been related to slab failure. Slab failure magmatism explains varying contributions of mafic and felsic magmas in post-collision orogenic settings. It is therefore of major importance in understanding crustal accretion. However, the source and nature of any mantle derived contribution is poorly understood. This study reveals that Ratagain is not only transitional in nature between the high Basingle bondSr calc-alkaline granites and syenite intrusions of the Northern Highlands Terrane, but overlaps with the entire compositional range of the NHG suite. New lithogeochemical data from Ratagain confirm remarkably high Sr (>1600 ppm) and Ba (>2200 ppm) contents, high LREEs, notable depletions in Nb, U, P and Ti, low HREEs and negligible Eu anomalies, associated with high initial 87Sr/86Sr (0.7055 to 0.7062) and low εNd (− 11.8 to −13.3). Although mafic parts of the complex have strong elemental and isotopic similarities with broadly coeval lamprophyres, signalling derivation from enriched mantle sources, details of the isotope array with respect to local crustal reservoirs indicate a significant Lewisian component. Such geochemical characteristics, combined with tectonic and petrological evidence, may be attributable to long-lived, incremental emplacement of successive magma batches originating from the same enriched mantle but differing in age and extent of assimilation-fractionation crystallisation. We therefore propose that some of the age dates for the Late Caledonian intrusions, particularly those obtained from older geochronology studies, are in need of review as they may record early crystallisation in the deep crust and not be a valid proxy for granite emplacement
An Integrated Content and Metadata based Retrieval System for Art
In this paper we describe aspects of the Artiste project to develop a distributed content and metadata based analysis, retrieval and navigation system for a number of major European Museums. In particular, after a brief overview of the complete system, we describe the design and evaluation of some of the image analysis algorithms developed to meet the specific requirements of the users from the museums. These include a method for retrievals based on sub images, retrievals based on very low quality images and retrieval using craquelure type
Evolution of Siderian juvenile crust to Rhyacian high Ba-Sr magmatism in the Mineiro Belt, southern São Francisco Craton
Plutonic rocks from the Mineiro Belt, Brazil record a delayed onset of the transition from TTG to sanukitoid-type magmatism (high Ba-Sr), starting during the Siderian magmatic lull when little juvenile magma was added to the continental crust. Rocks mostly belong to the calc-alkaline series, meta- to peraluminous and originally “I-type”, meaning that oxidized magmas were formed by partial melting of subducted material. The temporal distribution and apparent secular changes of the magmas are consistent with the onset of subduction-driven plate tectonics due to an increase of the subduction angle and opening of the mantle wedge. New isotopic analyses (Sm-Nd whole rock and Lu-Hf in zircon) corroborate the restricted juvenile nature of the Mineiro Belt and confirm the genetic link between the Lagoa Dourada Suite, a rare ca. 2350 Ma high-Al tonalite-trondhjemite magmatic event, and the sanukitoid-type ca. 2130 Ma Alto Maranhão Suite. U-Pb dating of zircon and titanite constrain the crystallisation history of plutonic bodies; coupled with major and trace element analyses of the host rocks, they distinguish evolutionary trends in the Mineiro Belt. Several plutons in the region have ages close to 2130 Ma but are distinguished by the lower concentration of compatible elements in the juvenile high Ba-Sr suite. Keywords: São Francisco Craton, Magmatic lull, TTG-Sanukitoid transition, Zircon U-Pb-Hf, Titanite U-Pb, Whole rock Nd isotope
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Biodiversity 2020: climate change evaluation report
In 2011, the government published Biodiversity 2020: A strategy for England’s wildlife and ecosystem services [1]. This strategy for England builds on the 2011 Natural Environment White Paper - NEWP [2] and provides a comprehensive picture of how we are implementing our international and EU commitments. It sets out the strategic direction for biodiversity policy between 2011-2020 on land (including rivers and lakes) and at sea, and forms part of the UK’s commitments under the ‘the Aichi targets’ agreed in 2010 under the United Nations Convention of Biological Diversity’s Strategic Plan for Biodiversity 2011-2020 [3].
Defra is committed to evaluating the Biodiversity 2020 strategy and has a public commitment to assess climate change adaptation measures. This document sets out the information on assessing how action under Biodiversity 2020 has helped our wildlife and ecosystems to adapt to climate change. Biodiversity 2020 aims to halt the loss of biodiversity and restore functioning ecosystems for wildlife and for people. The outcomes and actions in Biodiversity 2020, although wider in scope, aimed to increase resilience of our wildlife and ecosystems in the face of a changing climate. In order to inform the assessment, we have defined which of the measurable outputs under Biodiversity 2020 contribute to resilience. Biodiversity 2020 included plans to develop and publish a dedicated set of indicators to assess progress towards the delivery of the strategy. The latest list (at the time of writing), published in 2017, contains 24 biodiversity indicators [4] that would help inform progress towards achieving specific outcomes, they are also highly relevant to the outputs (detailed below) that form the basis for this evaluation. The Adaptation Sub-Committee’s 2017 UK Climate Change Risk Assessment Evidence Report [5] sets out the priority climate change risks and opportunities for the UK. The ASC also produced a review of progress in the National Adaptation Programme - “Progress in preparing for climate change” [6], which highlights adaptation priorities and progress being made towards achieving them. The UK Government’s response to the ASC [7] review includes a set of recommendations, of which Recommendation 6 states that “Action should be taken to enhance the condition of priority habitats and the abundance and range of priority species”. The recommendation further iterated that “This action should maintain or extend the level of ambition that was included in Biodiversity 2020” and that “An evaluation should be undertaken of Biodiversity 2020 including the extent to which goals have been met and of the implications for resilience to climate change.” To this, end an evaluation process has been put in place to define:
a. What worked and why? Which actions or activities have had the greatest benefit in terms of delivering the desired outcomes? And, conversely, what prevented progress?
b. Where are the opportunities? What are the financial, political, scientific and social opportunities for furthering the desired outcomes in the future?
These objectives underpin the evaluation process for actions to date, and will also inform future actions and the iteration of a new nature strategy for England
MiR-15a/miR-16-1 expression inversely correlates with cyclin D1 levels in Men1 pituitary NETs
Multiple Endocrine Neoplasia type 1 (MEN1) is an autosomal dominant disorder
characterised by the combined occurrence of parathyroid, pituitary and pancreatic islet
tumours, and is due to mutations of the MEN1 gene, which encodes the tumour suppressor
protein menin. Menin has multiple roles in genome stability, transcription, cell division and
proliferation, but its mechanistic roles in tumourigenesis remain to be fully elucidated.
MicroRNAs (miRNA) are non-coding single stranded RNAs that post-transcriptionally
regulate gene expression and have been associated with tumour development, although the
contribution of miRNAs to MEN1-associated tumourigenesis and their relationship with
menin expression are not fully understood. Alterations in miRNA expression, including
downregulation of three putative ‘tumour suppressor’ miRNAs, miR-15a, miR-16-1 and let 7a, have been reported in several tumour types including non-MEN1 pituitary adenomas. We
have therefore investigated the expression of miR-15a, miR-16-1 and let-7a in pituitary
tumours that developed after 12 months of age in female mice with heterozygous knock out
of the Men1 gene (Men1+/- 41 mice). The miRNAs miR-15a, miR-16-1 and let-7a were
significantly downregulated in pituitary tumours (by 2.3-fold, p<0.05; 2.1-fold p<0.01 and
1.6-fold p<0.05, respectively) of Men1+/- 43 mice, compared to normal wild type pituitaries.
MiR-15a and miR-16-1 expression inversely correlated with expression of cyclin D1, a
known pro-tumourigenic target of these miRNAs, and knock down of menin in a human
cancer cell line (HeLa), and AtT20 mouse pituitary cell line resulted in significantly
decreased expression of miR-15a (p<0.05), indicating that the decrease in miR-15a may be a
direct result of lost menin expression
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Right Turn Veteran-Specific Recovery Service: 5 site evaluation pilot: Interim report
The Right Turn project works with the ex-service personnel community in recovery from substance misuse. This report presents the interim findings from a two-year evaluation on the impact on health and wellbeing outcomes on military veterans engaging in this innovative peer-focussed recovery service. The evaluation is designed around a structured quantitative data collection process using an established repeat measure design and utilises qualitative methodologies to explore both the life experiences of this veteran cohort and to take account of their own perceptions of the model of services they feel they require. This report suggests that the military veteran community experience distinct barriers to accessing main stream health and wellbeing services. Alongside comorbidity issues, management of chronic physical conditions and social isolation, this report demonstrates that this cohort's own previous military conditioning forms a further barrier to accessing support services. This report contains recommendations to inform generic support staff when encountering veterans within health and wellbeing settings
Sr-isotopic ratios trace mixing and dispersion in CO2 push-pull injection experiments at the CO2CRC Otway Research Facility, Australia
Analysis of 87Sr/86Sr ratios and modelling of formation water, injection water and produced water compositions from the CO2CRC Otway Research Facility in Victoria, Australia are used to test tracer behaviour and response in push-pull experiments. Such experiments are an essential pre-requisite to understanding the controls imposed by reservoir heterogeneities on CO2 dissolution rates which may be an important stabilising mechanism for geological carbon storage. The experiments (Otway stage 2B extension in 2014) comprised two sequential tests in which ~100 t of CO2-saturated water was injected with combinations of Sr and Br or Li and Fluorescein tracers, each injection being followed by two staged extractions of ~10 t and a final extraction of ~50 t all spaced at ~10 day intervals. Analysis of the 87Sr/86Sr ratios of the produced fluids from the first injection, spiked with SrCl2 and NaBr, is consistent with Sr behaving conservatively. This contrasts with previous interpretations in which Br was argued to have behaved conservatively while Sr, which dilutes ~three times as fast as Br, was thought to be lost to a mineral phase. Such Sr-loss cannot explain the evolution of 87Sr/86Sr ratios. The analysis of 87Sr/86Sr ratios in the waters produced after the second injection episode, spiked with LiCl and Fluorescein tracers, allows calculation of the fractions of the formation waters and the injection waters from both tests 1 and 2. The Sr, Li and SO4 tracers (the later formed by oxidation of formation sulphide) all indicate similar rates of dilution that is consistent with conservative behaviour. The results of the two injection episodes with spaced extractions are compared with two subsequent push-pull injections in which the produced waters, spiked with methanol, were extracted continuously. These continuous extraction experiments exhibited significantly less dilution over the same range of produced to injected water volumes (up to only ~0.6) than the earlier experiments with spaced extractions. This implies that some process related to the pauses in extraction enhances mixing of injected and formation waters. Achieving the objective of using push-pull experiments to assess reservoir heterogeneities and CO2 dissolution rates will require better assessment of the various tracers to establish which behave conservatively followed a proper understanding of the causes of the variations in mixing as fluids are extracted from the formations
Bureau of Land Management
The authors wish to thank Steve Leonard and George Staidle, who authored Technical Reference 1737-5, Riparian and Wetland Classification Review, which provided the basis for this document. We also thank those who reviewed and commented on Technical Reference 1737-5: Paul Hansen, Bill Platts, Bud Kovalchik
Probabilistic Sensitivity Analysis in Cost-Effectiveness Models: Determining Model Convergence in Cohort Models.
Probabilistic sensitivity analysis (PSA) demonstrates the parameter uncertainty in a decision problem. The technique involves sampling parameters from their respective distributions (rather than simply using mean/median parameter values). Guidance in the literature, and from health technology assessment bodies, on the number of simulations that should be performed suggests a 'sufficient number', or until 'convergence', which is seldom defined. The objective of this tutorial is to describe possible outcomes from PSA, discuss appropriate levels of accuracy, and present guidance by which an analyst can determine if a sufficient number of simulations have been conducted, such that results are considered to have converged. The proposed approach considers the variance of the outcomes of interest in cost-effectiveness analysis as a function of the number of simulations. A worked example of the technique is presented using results from a published model, with recommendations made on best practice. While the technique presented remains essentially arbitrary, it does give a mechanism for assessing the level of simulation error, and thus represents an advance over current practice of a round number of simulations with no assessment of model convergence
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