Ammonium Fluoride as a Hydrogen-disordering Agent for Ice

The removal of residual hydrogen disorder from various phases of ice with acid or base dopants at low temperatures has been a focus of intense research for many decades. As an antipode to these efforts, we now show using neutron diffraction that ammonium fluoride (NH4F) is a hydrogen-disordering agent for the hydrogen-ordered ice VIII. Cooling its hydrogen-disordered counterpart ice VII doped with 2.5 mol% ND4F under pressure leads to a hydrogen-disordered ice VIII with ~31% residual hydrogen disorder illustrating the long-range hydrogen-disordering effect of ND4F. The doped ice VII could be supercooled by ~20 K with respect to the hydrogen-ordering temperature of pure ice VII after which the hydrogen-ordering took place slowly over a ~60 K temperature window. These findings demonstrate that ND4F-doping slows down the hydrogen-ordering kinetics quite substantially. The partial hydrogen order of the doped sample is consistent with the antiferroelectric ordering of pure ice VIII. Yet, we argue that local ferroelectric domains must exist between ionic point defects of opposite charge. In addition to the long-range effect of NH4F-doping on hydrogen-ordered water structures, the design principle of using topological charges should be applicable to a wide range of other 'ice-rule' systems including spin ices and related polar materials.Comment: 23 pages, 4 figures, 2 table

Moving Beyond the “Lump-Sum”: A Case Study of Partnership for Positive Social Change

Based on a foundation of an integrated sport program for positive social change and health promotion, this paper presents a case study of the relationship between a corporate sponsor (JP Morgan), and a community-based health promotion/social change organization (Football United). The paper articulates the various issues that arise in management of such a program, and the involvement of sponsors in its operation. Illustrated through the JP Morgan - Football United case study, the paper explores: the difficulties of maintaining a program that remains faithful to the expectations and demands of each stakeholder group involved; the challenges involved in harnessing support for a program when moving beyond the one-dimensional transfer of funds; the different needs and expectations of/for volunteers this type of complex health promotion intervention. This case study has been written to propose that an “integrated partnership” between a corporate body and a social change organization can produce significant advantages beyond the scope of uncomplicated financial contribution The key feature documented is that corporate investment can move beyond abstract “lump-sum” social responsibility, towards targeted contributions to detailed outcomes through sustainable and meaningful involvement in a health promotion framework. This in turn equates to funding stability and a more empowering partnership for the health promotion/social change organization

Macroeconomic Modeling of Tax Policy: A Comparison of Current Methodologies

The macroeconomic effects of tax reform are a subject of significant discussion and controversy. In 2015, the House of Representatives adopted a new “dynamic scoring” rule requiring a point estimate within the budget window of the deficit effect due to the macroeconomic response to certain proposed tax legislation. The revenue estimates provided by the staff of the Joint Committee on Taxation (JCT) for major tax bills often play a critical role in Congressional deliberations and public discussion of those bills. The JCT has long had macroeconomic analytic capability, and in recent years, responding to Congress’ interest in macrodynamic estimates for purposes of scoring legislation, outside think tank groups — notably the Tax Policy Center and the Tax Foundation — have also developed macrodynamic estimation models. The May 2017 National Tax Association (NTA) Spring Symposium brought together the JCT with the Tax Foundation and the Tax Policy Center for a panel discussion regarding their respective macrodynamic estimating approaches. This paper reports on that discussion. Below each organization provides a general description of their macrodynamic modeling methodology and answers five questions posed by the convening authors

The planform mobility of river channel confluences: Insights from analysis of remotely sensed imagery

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.River channel confluences are widely acknowledged as important geomorphological nodes that control the downstream routing of water and sediment, and which are locations for the preservation of thick fluvial deposits overlying a basal scour. Despite their importance, there has been little study of the stratigraphic characteristics of river junctions, or the role of confluence morphodynamics in influencing stratigraphic character and preservation potential. As a result, although it is known that confluences can migrate through time, models of confluence geomorphology and sedimentology are usually presented from the perspective that the confluence remains at a fixed location. This is problematic for a number of reasons, not least of which is the continuing debate over whether it is possible to discriminate between scour that has been generated by autocyclic processes (such as confluence scour) and that driven by allocyclic controls (such as sea-level change). This paper investigates the spatial mobility of river confluences by using the 40-year record of Landsat Imagery to elucidate the styles, rates of change and areal extent over which large river confluence scours may migrate. On the basis of these observations, a new classification of the types of confluence scour is proposed and applied to the Amazon and Ganges-Brahmaputra-Meghna (GBM) basins. This analysis demonstrates that the drivers of confluence mobility are broadly the same as those that drive channel change more generally. Thus in the GBM basin, a high sediment supply, large variability in monsoonal driven discharge and easily erodible bank materials result in a catchment where over 80% of large confluences are mobile over this 40-year window; conversely this figure is < 40% for the Amazon basin. These results highlight that: i) the potential areal extent of confluence scours is much greater than previously assumed, with the location of some confluences on the Jamuna (Brahmaputra) River migrating over a distance of 20 times the tributary channel width; ii) extensive migration in the confluence location is more common than currently assumed, and iii) confluence mobility is often tied to the lithological and hydrological characteristics of the drainage basins that determine sediment yield.This work was funded by NERC grant NE/I023228/1 to Sambrook Smith, Bull, Nicholas and Best

Peer support for parents of disabled children part 2: how organizational and process factors influenced shared experience in a one-to-one service, a qualitative study

Background: Parents of disabled children often seek support from their peers. The shared experience between parents appears to be a crucial mediating factor. Understanding how a sense of shared experience is fostered can help to design and evaluate services that seek to provide peer support. Methods: We carried out a qualitative study involving semi-structured interviews and focus groups. Participants were 12 parents and 23 befrienders who had contact with the Face2Face one-to-one befriending service in Devon and Cornwall during a 12-month period, and 10 professionals from health, social care and education. Findings: Formal structures and processes in place such as training and ongoing supervision and support were highly valued as was the highly personalized, confidential, flexible, one-to-one at-home nature of the service. Crucial to establishing rapport was putting the right people together and ensuring a good match between befrienders and parents. Clearly, the befriending parent has to be emotionally prepared to provide help. However, if the parent being offered support was not ready to accept help at the time it was offered or the type of support was not right for them, they are less likely to engage with the service. Conclusion: Organizational and process factors as well as characteristics of the parents offering and receiving support contribute to the sense of shared experience in one-to-one peer support. These factors interact to influence whether peer support is effective and should be explicitly considered when designing and evaluating services. © 2015 John Wiley & Sons Ltd

iPregel: Strategies to Deal with an Extreme Form of Irregularity in Vertex-Centric Graph Processing

Over the last decade, the vertex-centric programming model has attracted significant attention in the world of graph processing, resulting in the emergence of a number of vertex-centric frameworks. Its simple programming interface, where computation is expressed from a vertex point of view, offers both ease of programming to the user and inherent parallelism for the underlying framework to leverage. However, vertex-centric programs represent an extreme form of irregularity, both inter and intra core. This is because they exhibit a variety of challenges from a workload that may greatly vary across supersteps, through fine-grain synchronisations, to memory accesses that are unpredictable both in terms of quantity and location. In this paper, we explore three optimisations which address these irregular challenges; a hybrid combiner carefully coupling lock-free and lock-based combinations, the partial externalisation of vertex structures to improve locality and the shift to an edge-centric representation of the workload. The optimisations were integrated into the iPregel vertex-centric framework, enabling the evaluation of each optimisation in the context of graph processing across three general purpose benchmarks common in the vertex-centric community, each run on four publicly available graphs covering all orders of magnitude from a million to a billion edges. The result of this work is a set of techniques which we believe not only provide a significant performance improvement in vertex-centric graph processing, but are also applicable more generally to irregular applications.Comment: Preprint of paper submitted to 9th Workshop on Irregular Applications: Architectures and Algorithms (IA3

Peer support for parents of children with chronic disabling conditions: a systematic review of quantitative and qualitative studies

AIM: To review the qualitative and quantitative evidence of the benefits of peer support for parents of children with disabling conditions in the context of health, well-being, impact on family, and economic and service implications. Method: We comprehensively searched multiple databases. Eligible studies evaluated parent-to-parent support and reported on the psychological health and experience of giving or receiving support. There were no limits on the child's condition, study design, language, date, or setting. We sought to aggregate quantitative data; findings of qualitative studies were combined using thematic analysis. Qualitative and quantitative data were brought together in a narrative synthesis. Results: Seventeen papers were included: nine qualitative studies, seven quantitative studies, and one mixed-methods evaluation. Four themes were identified from qualitative studies: (1) shared social identity, (2) learning from the experiences of others, (3) personal growth, and (4) supporting others. Some quantitative studies reported a positive effect of peer support on psychological health and other outcomes; however, this was not consistently confirmed. It was not possible to aggregate data across studies. No costing data were identified. Conclusion: Qualitative studies strongly suggest that parents perceive benefit from peer support programmes, an effect seen across different types of support and conditions. However, quantitative studies provide inconsistent evidence of positive effects. Further research should explore whether this dissonance is substantive or an artefact of how outcomes have been measured. © The Authors © 2013 Mac Keith Press

Density-driven structural transformations in B2O3 glass

The method of in situ high-pressure neutron diffraction is used to investigate the structure of B2O3 glass on compression in the range from ambient to 17.5(5) GPa. The experimental results are supplemented by molecular dynamics simulations made using a newly developed aspherical ion model. The results tie together those obtained from other experimental techniques to reveal three densification regimes. In the first, BO3 triangles are the predominant structural motifs as the pressure is increased from ambient to 6.3(5) GPa, but there is an alteration to the intermediate range order which is associated with the dissolution of boroxol rings. In the second, BO4 motifs replace BO3 triangles at pressures beyond 6.3 GPa and the dissolution of boroxol rings continues until it is completed at 11–14 GPa. In the third, the B-O coordination number continues to increase with pressure to give a predominantly tetrahedral glass, a process that is completed at a pressure in excess of 22.5 GPa. On recovery of the glass to ambient from a pressure of 8.2 GPa, triangular BO3 motifs are recovered but, relative to the uncompressed material, there is a change to the intermediate range order. The comparison between experiment and simulation shows that the aspherical ion model is able to provide results of unprecedented accuracy at pressures up to at least 10 GPa