1,202 research outputs found

    Reflection on-line or off-line: the role of learning technologies in encouraging students to reflect

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    This paper presents case studies that describe the experiences of the two authors in trying to use learning technologies to facilitate reflective thinking in their students. At the University of Leicester, a Web-based biology tutorial called ‘How Now Mad Cow’, which covers the topics of bovine spongiform encephalopathy and a new variant Creutzfeldt–Jakob disease (nvCJD). At the University of Southampton, a web-based hyper-mail discussion list to support teaching on a first year psychosocial science module for occupational therapy and physiotherapy students has been established. In both examples, the tutors had attempted to create a learning environment that would engage students in the learning experience and facilitate reflection by helping them to create meaning from the learning experience and see things in a different way. The evaluation data from both case studies provides some evidence that the learning technologies helped to facilitate reflection for some students. However, the evidence for reflection is not overwhelming and the data provides some evidence that four key factors may have influenced how successful the use of learning technologies were in facilitating reflection. These factors are the way the learning technology is used, the nature of the student groups, the role of the tutor and student preferences for ‘off-line reflection’. These are discussed and ways forward are identified

    Zirconia phase transformation in retrieved, wear simulated and artificially aged ceramic femoral heads

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    Zirconia in Zirconia toughened alumina ceramic hip replacements exists in an unstable state and can transform in response to stress giving the material improved fracture toughness. Phase transformation also occurs under hydrothermal conditions such as exist in vivo. To predict the hydrothermal aging that will occur in vivo accelerated aging procedures have been used, but validation of these models requires the study of retrieved hip joints. Here 26 retrievals are analysed to determine the degree of phase transformation in vivo. These were compared with virgin heads, heads that had undergone the accelerated aging process and heads wear tested to 5 million cycles in a hip simulator. Monoclinic content and surface roughness were measured using Raman spectroscopy and white light interferometry respectively. The monoclinic content for retrieved heads was 28.5% ± 7.8, greater than twice that in virgin, aged or wear tested heads and did not have a significant correlation with time, contrary to the predictions of the hydrothermal aging model. The surface roughness for retrieved heads in the unworn area was not significantly different to that in virgin, aged or unworn areas of wear tested heads. However in worn areas of the retrieved heads, the surface roughness was higher than observed in wear simulator testing. These results indicate that current testing methodologies do not fully capture the operational conditions of the material and the real performance of future new materials may not be adequately predicted by current pre-clinical testing methods. This article is protected by copyright. All rights reserve

    Buried Black Hole Growth in IR-selected Mergers: New Results from Chandra

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    Observations and theoretical simulations suggest that a significant fraction of merger-triggered accretion onto supermassive black holes is highly obscured, particularly in late-stage galaxy mergers, when the black hole is expected to grow most rapidly. Starting with the Wide-Field Infrared Survey Explorer all-sky survey, we identified a population of galaxies whose morphologies suggest ongoing interaction and which exhibit red mid-infrared colors often associated with powerful active galactic nuclei (AGNs). In a follow-up to our pilot study, we now present Chandra/ACIS and XMM-Newton X-ray observations for the full sample of the brightest 15 IR-preselected mergers. All mergers reveal at least one nuclear X-ray source, with 8 out of 15 systems exhibiting dual nuclear X-ray sources, highly suggestive of single and dual AGNs. Combining these X-ray results with optical line ratios and with near-IR coronal emission line diagnostics, obtained with the near-IR spectrographs on the Large Binocular Telescope, we confirm that 13 out of the 15 mergers host AGNs, two of which host dual AGNs. Several of these AGNs are not detected in the optical. All X-ray sources appear X-ray weak relative to their mid-infrared continuum, and of the nine X-ray sources with sufficient counts for spectral analysis, eight reveal strong evidence of high absorption with column densities of NH≳1023N_\mathrm{H} \gtrsim 10^{23}~cm−2^{-2}. These observations demonstrate that a significant population of single and dual AGNs are missed by optical studies, due to high absorption, adding to the growing body of evidence that the epoch of peak black hole growth in mergers occurs in a highly obscured phase.Comment: 29 pages, 22 figures; (Main text: 17 pages, 4 figures

    A Behaviour Change Analysis of Safer Sleep Interventions for Infants at Risk of Sudden and Unexpected Death

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    \ua9 2024 The Authors. Child Abuse Review published by Association of Child Protection Professionals and John Wiley & Sons Ltd.Rates of sudden unexpected death in infancy have been found to occur disproportionately amongst families living in the most deprived neighbourhoods. This suggests that standard safer sleep messaging may not be effective for this population and that research is required to identify ways of working that are better associated with behavioural change in parents with children at increased risk of SUDI. In this study, we aimed to explore the behavioural change components and mechanisms of action of safer sleep interventions for families with children at increased risk of SUDI. We conducted an analysis of the literature on safer sleep interventions using the COM-B model, Theoretical Domains Framework and Behavioural Change Technique Taxonomy. All interventions targeted parents\u27 capability; 15 interventions targeted parents\u27 opportunity; and six interventions targeted parents\u27 motivation to engage in safer sleep practices. Nineteen behavioural change techniques were identified. The focus of practitioners may need to shift from solely the delivery of safer sleep information towards working with parents to understand their capability, opportunity and, in particular, motivation to engage in safer sleep practices, identified as being a key driver of behaviour in this population

    Parental decision making about safer sleep practices: A qualitative study of the perspectives of families with additional health and social care needs

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    \ua9 2024 Barrett et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Introduction Despite a decline in Sudden Unexpected Death in Infancy in the UK since 2004, inequalities have widened with higher rates among families from deprived backgrounds and those known to child protection services. Almost all cases involve parents who had engaged in unsafe sleeping practices despite awareness of safer sleeping advice. Objective To understand the perspectives surrounding safer sleep of families supported by statutory child protection agencies, and use behavior change theory to inform how approaches to providing safer sleep advice to these families may be modified. Participants and setting We interviewed 14 mothers, 2 fathers and one grandmother, who had recent contact with child protection services in northeast England. Methods In-depth, semi-structured interviews, with purposive sampling. The COM-B model (Capability, Opportunity, and Motivation) structured our analysis. Results Parents described how anxiety, sleep deprivation, settling infants, illness, and a desire to bond with infants influence their decision making about sleep. Parents valued credible, trusted sources and understanding how safer sleep practices protect infants. Responses to questions about \u27out of routine\u27 situations suggested social pressures surrounding routines and \u27good parenting\u27 may preclude parents from acknowledging risks and planning for these situations. Conclusion Open conversations tailored to the needs of families, focused upon understanding why and when parent(s) do or do not follow safer sleep guidance seem a promising way of promoting safer sleep practices. Safer sleep discussions with these families are likely to be best delivered as part of wider infant care by professionals who have an established and continuing trusting relationship with parents. While advice and information should be provided by any professional in contact with the family with the necessary expertise, sensitive conversations around sleeping practices, particularly co-sleeping, may be more easily facilitated by professionals where the statutory responsibility for safeguarding is less apparent

    Fabrication of photonic band gap crystal using microtransfer molded templates

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    We have proposed and demonstrated an economical technique to fabricate a three-dimensional layer-by-layer photonic band gapstructure in the infrared wavelengths. An organic polymer template structure, an inverse layer-by-layer photonic crystalstructure, is assembled using the microtransfer molding technique. This template is infiltrated with sol-gel or nanoparticle titanium oxide slurry, then later removed by heat treatment at a temperature range of 550–800 °C. This method can be extended to fabricatephotonic crystals operating at optical and ultraviolet frequencies

    An archaeal family-B DNA polymerase variant able to replicate past DNA damage: occurrence of replicative and translesion synthesis polymerases within the B family

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    A mutant of the high fidelity family-B DNA polymerase from the archaeon Thermococcus gorgonarius (Tgo-Pol), able to replicate past DNA lesions, is described. Gain of function requires replacement of the three amino acid loop region in the fingers domain of Tgo-Pol with a longer version, found naturally in eukaryotic Pol zeta (a family-B translesion synthesis polymerase). Inactivation of the 3'–5' proofreading exonuclease activity is also necessary. The resulting Tgo-Pol Z1 variant is proficient at initiating replication from base mismatches and can read through damaged bases, such as abasic sites and thymine photo-dimers. Tgo-Pol Z1 is also proficient at extending from primers that terminate opposite aberrant bases. The fidelity of Tgo-Pol Z1 is reduced, with amarked tendency tomake changes at G:C base pairs. Together, these results suggest that the loop region of the fingers domain may play a critical role in determining whether a family-B enzyme falls into the accurate genome-replicating category or is an errorprone translesion synthesis polymerase. Tgo-Pol Z1 may also be useful for amplification of damaged DNA

    Beyond mobile phone displays: Flat panel display technology for biomedical applications

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    Organ-on-Chips (OoCs) have emerged as a human-specific experimental platform for preclinical research and therapeutics testing that will reduce the cost of pre-clinical drug development, provide better physiological relevance and replace animal testing. Yet, the lack of standardization and cost-effective fabrication technologies can hamper wide-spread adoption of OoCs. In this work we validate the use of flat panel display (FPD) technology as an enabling and cost-effective technology platform for biomedical applications by demonstrating facile integration of key OoC modules like microfluidics and micro electrode arrays (MEAs) in the standardized 96-well plate format. Individual and integrated modules were tested for their biological applicability in OoCs. For microelectrode arrays we demonstrate 90–95% confluency, 3 days after cell seeding and >70% of the initial mitochondrial cell activity for microfluidic devices. Thus highlighting the biocompatibility of these modules fabricated using FPD technology. Furthermore, we provide two examples of monolithically integrated microfluidics and microelectronics, i.e. integrated electronic valves and integrated MEAs, that showcase the strength of FPD technology applied to biomedical device fabrication. Finally, the merits and opportunities provided by FPD technology are discussed through examples of advanced structures and functionalities that are unique to this enabling platform

    Finite-size scaling in silver nanowire films: design considerations for practical devices

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    We report the first application of finite-size scaling theory to nanostructured percolating networks, using silver nanowire (AgNW) films as a model system for experiment and simulation. AgNWs have been shown to be a prime candidate for replacing Indium Tin Oxide (ITO) in applications such as capacitive touch sensing. While their performance as large area films is well-studied, the production of working devices involves patterning of the films to produce isolated electrode structures, which exhibit finite-size scaling when these features are sufficiently small. We demonstrate a generalised method for understanding this behaviour in practical rod percolation systems, such as AgNW films, and study the effect of systematic variation of the length distribution of the percolating material. We derive a design rule for the minimum viable feature size in a device pattern, relating it to parameters which can be derived from a transmittance-sheet resistance data series for the material in question. This understanding has direct implications for the industrial adoption of silver nanowire electrodes in applications where small features are required including single-layer capacitive touch sensors, LCD and OLED display panels

    Widespread active detachment faulting and core complex formation near 13°N on the Mid-Atlantic Ridge

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    Author Posting. © Nature Publishing Group, 2006. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature 442 (2006): 440-443, doi:10.1038/nature04950.Oceanic core complexes are massifs in which lower crustal and upper mantle rocks are exposed at the sea floor. They form at mid-ocean ridges through slip on detachment faults rooted below the spreading axis. To date, most studies of core complexes have been based on isolated inactive massifs that have spread away from ridge axes. A new survey of the Mid-Atlantic Ridge (MAR) near 13°N reveals a segment in which a number of linked detachment faults extend for 75 km along one flank of the spreading axis. The detachment faults are apparently all currently active and at various stages of development. A field of extinct core complexes extends away from the axis for at least 100 km. The new data document the topographic characteristics of actively-forming core complexes and their evolution from initiation within the axial valley floor to maturity and eventual inactivity. Within the surrounding region there is a strong correlation between detachment fault morphology at the ridge axis and high rates of hydroacoustically-recorded earthquake seismicity. Preliminary examination of seismicity and seafloor morphology farther north along the MAR suggests that active detachment faulting is occurring in many segments and that detachment faulting is more important in the generation of ocean crust at this slow-spreading ridge than previously suspected.This work was supported by the National Science Foundation
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