Deformation-Induced Mechanical Instabilities at the Core-Mantle Boundary

Post-Perovskite: The Last Mantle Phase Transition Our understanding of the core-mantle boundary (CMB) region has improved significantly over the past several years due, in part, to the discovery of the post-perovskite phase. Sesimic data suggest that the CMB region is highly heterogeneous, possibly reflecting chemical and physical interaction between outer core material and the lowermost mantle. In this contribution we present the results of a new mechanism of mass transfer across the CMB and comment on possible repercussions that include the initiation of deep, siderophile-enriched mantle plumes. We view the nature of core-mantle interaction, and the geodynamic and geochemical ramifications, as multiscale processes, both spatially and temporally. Three lengthscales are defined. On the microscale (1-50 km), we describe the effect of loading and subsequent shearing of the CMB region and show how this may drive local flow of outer core fluid upwards into D". We propose that larger scale processes operating on a mesoscale (50-300 km) and macroscale regimes (> 300 km) are linked to the microscale, and suggest ways in which these processes may impact on global mantle dynamics

Reading newspapers: a theoretical description of a practical activity

A simple observation about the nature of reading initiated this project. The observation was that in reading we are able to use ink on paper as an equivalence of the real world event it details. Attempts to account for this by examining reading as it progresses did not give rise to clarification of this phenomenon, but solely to reading itself. Encounters with the text always resulting in 'ending-up-just-reading'. This is identifiable as a central characteristic of the material and the reader's attitude towards it. As this difficulty with the nature of the undertaking threatened to stop any theoretical progress, various methodologies, including Ethnomethodology, were applied to the material in order to produce a way forward. However, these theoretical approaches did not solve the phenomenon of reading but merely multiplied its problematic features. Their terms displacing the focus of attention away from reading, to the internal expression of the approach itself. Elsewhere within the project a more reflexive approach was adopted. Examining the roles of reader, theorist and author that were variously adopted. The recognition that the author in detailing experiences as a reader of texts succeeds only in creating another text. There is an examination of levels of access available to the project reader and the constraints this places on any reading that can be made. Otherwise expressed, it is the reading of one text through the confines of another, we are always trapped within the medium. From this recognition that 'viewing from within' is an intrinsic, inescapable feature of reading, a solution to 'ending-up-just reading' offers itself. Aspects of reading are made obvious by getting the reader to activate them, as they read of them. The solution is an ethnographical account of the reading of a newspaper story, an interpretive account. Its success may be gauged by the familiarity of its description and its expression of shared reading experiences and common reading practices

Numerical modelling of liquid metal transport in partially molten H5 ordinary chondrite

An equation-based model of liquid metal segregation in Fe-bearing chondrite meteorites is presented. Textural data from natural samples provide the input conditions. Initial results confirm porous flow of Fe-Ni-S liquid alloy as an important metal segregation mechanism in planetary interiors

Using interactive workshops to prompt knowledge exchange: a realist evaluation of a knowledge to action initiative

Introduction: Interactive workshops are often the default mechanism for sharing knowledge across professional and sector boundaries; yet we understand little about if, and how, they work. Between 2009 and 2011, the Research to Reality programme in North East England ran eight stand-alone facilitated multi-agency workshops focused on priority public health issues. Local authorities, the health service, and academe collaborated on the programme to share latest evidence and best practice. Methods: A realist evaluation asked the overarching question ‘what worked where, for whom, and under what conditions’ regarding the knowledge exchange (KE) mechanisms underpinning any changes. Data were collected from fifty-one interviews, six observations, and analysis of programme documentation. Results: 191 delegates attended (local authority 46%, NHS 24%, academia 22%, third sector 6%, other 2%). The programme theory was that awareness raising and critical discussion would facilitate ownership and evidence uptake. KE activity included: research digests, academic and senior practitioner presentations, and facilitated round-table discussions. Joint action planning was used to prompt informed follow-up action. Participants valued the digests, expert input, opportunities for discussion, networking and ‘space to think’. However, within a few months, sustainability was lost. There was no evidence of direct changes to practice. Multiple barriers to research utilization emerged. Discussion: The findings suggest that in pressured contexts exacerbated by structural reform providing evidence summaries, input from academic and practice experts, conversational spaces and personal action planning are necessary to create enthusiasm on the day, but are insufficient to prompt practice change in the medium term. The findings question makes assumptions about the instrumental, linear use of knowledge and of change focused on individuals as a driver for organizational change. Delegates' views of ‘what would work’ are shared. Mechanisms that would enhance interactive formats are discussed

Developing virtual public health networks: aspiration and reality

Background This paper presents the results of an exercise to scope the potential of a virtual network to support dissemination, collaboration and innovation among the UK research community on the topic of ‘work and health and well-being’. Methods Through a search of the literature and internet searches, a database of 333 individuals and 10 organizations (stakeholders) was developed to whom an online questionnaire was sent. The questionnaire scoped the potential of a virtual network on work and health and well-being. We compared respondents' aspirations for a network with the critical management literature examining the core conditions under which networks work best. Results We identified 1435 papers, published since 2008. In the UK, 333 individuals and 10 organizations were identified as working within the broad topic of Work and Health and Well-being. Of the 110 (a 34% response) responses to our online questionnaire, the majority (80%, n = 88) stated they would be interested in joining a virtual network. Conclusions Respondents indicated a willingness to engage with the network. They had a range of ideas regarding how a network could operate, which broadly match the conditions that support network effectiveness. A virtual-enabled network would be best supplemented by opportunities for face-to-face interaction

Shear-induced material transfer across the core-mantle boundary aided by the post-perovskite phase transition

We present a novel mechanical model for the extraction of outer core material upwards across the CMB into the mantle side region of D" and subsequent interaction with the post-perovskite (ppv) phase transition. A strong requirement of the model is that the D" region behaves as a poro-viscoelastic granular material with dilatant properties. Using new ab-initio estimates of the ppv shear modulus, we show how shear-enhanced dilation promoted by downwelling mantle sets up an instability that drives local fluid flow. If loading rates locally exceed c. 10-12 s-1 , calculated core metal upwelling rates are >10-4 m/s, far in excess of previous estimates based on static percolation or capillary flow. Associated mass flux rates are sufficient to deliver 0.5% outer core mass to D" in <10 6 yr, provided the minimum required loading rate is maintained. Core metal transported upwards into D" may cause local rapid changes in electrical and thermal conductivity and rheology that if preserved, may account for some of the observed small wavelength heterogeneties (e.g. PKP scattering) there

Norms for creativity and implementation in healthcare teams: testing the group innovation inventory

Abstract OBJECTIVE: To test to what extent the four-factor structure of the group innovation inventory (GII) is confirmed for improvement teams participating in a quality improvement collaborative. DESIGN: Quasi-experimental design with baseline and end-measurement after intervention. SETTING: This study included quality improvement teams participating in the Care for Better improvement programme for home care, care for the handicapped and the elderly in the Netherlands between 2006 and 2008. PARTICIPANTS: As part of a larger evaluation study, 261 written questionnaires from team members were collected at baseline (pre-project sample) and 129 questionnaires at end-measurement (post-project sample). MAIN OUTCOME MEASURE: Group innovation inventory. RESULTS: Confirmatory factor analyses revealed the expected four-factor structure and good fit indices. The subscales 'group functioning' and 'speed of action' showed acceptable Cronbach's alphas and high inter-item correlations. The subscales 'support for risk taking' and 'tolerance of mistakes' showed insufficient reliability and validity. CONCLUSIONS: The group functioning and speed of action subscales of the GII showed acceptable psychometric properties and are applicable to quality improvement teams in health care. In order to understand how social expectations within teams working in health care organizations exert influence over attitudes and behaviours thought to stimulate creativity, further conceptualization of the norms for enhancing creativity within health care is needed

Performing collaborative research: a dramaturgical reflection on an institutional knowledge brokering service in the North East of England

Background: To increase the uptake of research evidence in practice, responsive research services have been developed within universities that broker access to academic expertise for practitioners and decision-makers. However, there has been little examination of the process of knowledge brokering within these services. This paper reflects on this process within the AskFuse service, which was launched in June 2013 by Fuse, the Centre for Translational Research in Public Health, in North East England. The paper outlines the challenges and opportunities faced by both academics and health practitioners collaborating through the service. Methods: The authors reflected on conversations between the AskFuse Research Manager and policy and practice partners accessing the service between June 2013 and March 2017. Summary notes of these conversations, including emails and documents relating to over 240 enquiries, have been analysed using an auto-ethnographic approach. Findings: We identified five challenges to knowledge brokering in an institutional service, namely length of brokerage time required, limits to collaboration, lack of resources, brokering research in a changing system, and multiple types of knowledge. Conclusions: To understand and overcome some of the identified challenges, we employ Goffman's dramaturgical perspective and argue for making better use of the distinction between front and back stages in the knowledge brokering process. We emphasise the importance of back stages for defusing destructive information that could discredit collaborative performances