Boundary effect of a partition in a quantum well

The paper wishes to demonstrate that, in quantum systems with boundaries, different boundary conditions can lead to remarkably different physical behaviour. Our seemingly innocent setting is a one dimensional potential well that is divided into two halves by a thin separating wall. The two half wells are populated by the same type and number of particles and are kept at the same temperature. The only difference is in the boundary condition imposed at the two sides of the separating wall, which is the Dirichlet condition from the left and the Neumann condition from the right. The resulting different energy spectra cause a difference in the quantum statistically emerging pressure on the two sides. The net force acting on the separating wall proves to be nonzero at any temperature and, after a weak decrease in the low temperature domain, to increase and diverge with a square-root-of-temperature asymptotics for high temperatures. These observations hold for both bosonic and fermionic type particles, but with quantitative differences. We work out several analytic approximations to explain these differences and the various aspects of the found unexpectedly complex picture.Comment: LaTeX (with iopart.cls, iopart10.clo and iopart12.clo), 28 pages, 17 figure

Curating media learning: Towards a porous expertise

This article combines research results from a range of projects with two consistent themes. Firstly, we explore the potential for curation to offer a productive metaphor for the convergence of digital media learning across and between home / lifeworld and formal educational / systemworld spaces – or between the public and private spheres. Secondly, we draw conclusions from these projects to argue that the acceptance of transmedia literacy practices as a site for rich educational work – in media education and related areas – can only succeed if matched by a convergence of a more porous educator–student expertise

Reading Videogames as (authorless) Literature

This article presents the outcomes of research, funded by the Arts and Humanities Research Council in England and informed by work in the fields of new literacy research, gaming studies and the socio-cultural framing of education, for which the videogame L.A. Noire (Rockstar Games, 2011) was studied within the orthodox framing of the English Literature curriculum at A Level (pre-University) and Undergraduate (degree level). There is a plethora of published research into the kinds of literacy practices evident in videogame play, virtual world engagement and related forms of digital reading and writing (Gee, 2003; Juul, 2005; Merchant, Gillen, Marsh and Davies, 2012; Apperley and Walsh, 2012; Bazalgette and Buckingham, 2012) as well as the implications of such for home / school learning (Dowdall, 2006; Jenkins, 2006; Potter, 2012) and for teachers’ own digital lives (Graham, 2012). Such studies have tended to focus on younger children and this research is also distinct from such work in the field in its exploration of the potential for certain kinds of videogame to be understood as 'digital transformations' of conventional ‘schooled’ literature. The outcomes of this project raise implications of such a conception for a further implementation of a ‘reframed’ literacy (Marsh, 2007) within the contemporary curriculum of a traditional and conservative ‘subject’. A mixed methods approach was adopted. Firstly, students contributing to a gamplay blog requiring them to discuss their in-game experience through the ‘language game’ of English Literature, culminating in answering a question constructed with the idioms of the subject’s set text ‘final examination’. Secondly, students taught their teachers to play L.A. Noire, with free choice over the context for this collaboration. Thirdly, participants returned to traditional roles in order to work through a set of study materials provided, designed to reproduce the conventions of the ‘study guide’ for literature education. Interviews were conducted after each phase and the outcomes informed a redrafting of the study materials which are now available online for teachers – this being the ‘practical’ outcome of the research (Berger and McDougall, 2012). In the act of inserting the study of L.A. Noire into the English Literature curriculum as currently framed, this research moves, through a practical ‘implementation’ beyond longstanding debates around narratology and ludology (Frasca, 2003; Juul, 2005) in the field of game studies (Leaning, 2012) through a direct connection to new literacy studies and raises epistemological questions about ‘subject identity’, informed by Bernstein (1996) and Bourdieu (1986) and the implications for digital transformations of texts for both ideas about cultural value in schooled literacy (Kendall and McDougall, 2011) and the politics of ‘expertise’ in pedagogic relations (Ranciere, 2009, Bennett, Kendall and McDougall, 2012a)

Exploring the behavioural drivers of veterinary surgeon antibiotic prescribing: a qualitative study of companion animal veterinary surgeons in the UK

Background: Multi-drug resistant bacteria are an increasing concern in both human and veterinary medicine. Inappropriate prescribing and use of antibiotics within veterinary medicine may be a contributory factor to antimicrobial resistance (AMR). The ‘One Health’ Initiative aims to work across species and environments to reduce AMR, however; little is currently known about the factors which influence antibiotic prescribing among veterinary surgeons in companion animal practice. This paper reports on qualitative data analysis of interviews with veterinary surgeons whose practice partially or wholly focuses on companion animals (N = 16). The objective of the research was to explore the drivers of companion animal veterinary surgeons’ antibiotic prescribing behaviours. The veterinary surgeons interviewed were all practising within the UK (England (n = 4), Scotland (n = 11), Northern Ireland (n = 1)). A behavioural thematic analysis of the data was undertaken, which identified barriers and facilitators to specific prescribing-related behaviours. Results: Five components of prescribing behaviours were identified: 1) confirming clinical need for antibiotics; 2) responding to clients; 3) confirming diagnosis; 4) determining dose, duration and type of antibiotic; and 5) preventing infection around surgery (with attendant appropriate and inappropriate antibiotic prescribing behaviours). Barriers to appropriate prescribing identified include: business, diagnostic, fear, habitual practice and pharmaceutical factors. Facilitators include: AMR awareness, infection prevention, professional learning and regulation and government factors. Conclusion: This paper uses a behavioural lens to examine drivers which are an influence on veterinary surgeons’ prescribing behaviours. The paper contributes new understandings about factors which influence antibiotic prescribing behaviours among companion animal veterinary surgeons. This analysis provides evidence to inform future interventions, which are focused on changing prescribing behaviours, in order to address the pressing public health concern of AMR

Designing informative warning signals: Effects of indicator type, modality, and task demand on recognition speed and accuracy

An experiment investigated the assumption that natural indicators which exploit existing learned associations between a signal and an event make more effective warnings than previously unlearned symbolic indicators. Signal modality (visual, auditory) and task demand (low, high) were also manipulated. Warning effectiveness was indexed by accuracy and reaction time (RT) recorded during training and dual task test phases. Thirty-six participants were trained to recognize 4 natural and 4 symbolic indicators, either visual or auditory, paired with critical incidents from an aviation context. As hypothesized, accuracy was greater and RT was faster in response to natural indicators during the training phase. This pattern of responding was upheld in test phase conditions with respect to accuracy but observed in RT only in test phase conditions involving high demand and the auditory modality. Using the experiment as a specific example, we argue for the importance of considering the cognitive contribution of the user (viz., prior learned associations) in the warning design process. Drawing on semiotics and cognitive psychology, we highlight the indexical nature of so-called auditory icons or natural indicators and argue that the cogniser is an indispensable element in the tripartite nature of signification

Transplantation of Skeletal Muscle-Derived Sca-1⁺/PW1⁺/Pax7⁻ Interstitial Cells (PICs) Improves Cardiac Function and Attenuates Remodeling in Mice Subjected to Myocardial Infarction

We have previously shown that skeletal muscle-derived Sca-1⁺/PW1⁺/Pax7⁻ interstitial cells (PICs) are multi-potent and enhance endogenous repair and regeneration. Here, we investigated the regenerative potential of PICs following intramyocardial transplantation in mice subjected to an acute myocardial infarction (MI). MI was induced through the ligation of the left anterior descending coronary artery in 8-week old male C57BL/6 mice. 5 × 10⁵ eGFP-labelled PICs (MI + PICs; n = 7) or PBS (MI-PBS; n = 7) were injected intramyocardially into the border zone. Sham mice (n = 8) were not subjected to MI, or the transplantation of PICs or PBS. BrdU was administered via osmotic mini-pump for 14 days. Echocardiography was performed prior to surgery (baseline), and 1-, 3- and 6-weeks post-MI and PICs transplantation. Mice were sacrificed at 6 weeks post-MI + PICs transplantation, and heart sections were analysed for fibrosis, hypertrophy, engraftment, proliferation, and differentiation of PICs. A significant (\u1d631 < 0.05) improvement in ejection fraction (EF) and fractional shortening was observed in the MI-PICs group, compared to MI + PBS group at 6-weeks post MI + PICs transplantation. Infarct size/fibrosis of the left ventricle significantly (\u1d631 < 0.05) decreased in the MI-PICs group (14.0 ± 2.5%), compared to the MI-PBS group (32.8 ± 2.2%). Cardiomyocyte hypertrophy in the border zone significantly (\u1d631 < 0.05) decreased in the MI-PICs group compared to the MI-PBS group (330.0 ± 28.5 µM2 vs. 543.5 ± 26.6 µm2), as did cardiomyocyte apoptosis (0.6 ± 0.9% MI-PICs vs. 2.8 ± 0.8% MI-PBS). The number of BrdU+ cardiomyocytes was significantly (\u1d631 < 0.05) increased in the infarct/border zone of the MI-PICs group (7.0 ± 3.3%), compared to the MI-PBS group (1.7 ± 0.5%). The proliferation index (total BrdU+ cells) was significantly increased in the MI-PICs group compared to the MI-PBS group (27.0 ± 3.4% vs. 7.6 ± 1.0%). PICs expressed and secreted pro-survival and reparative growth factors, supporting a paracrine effect of PICs during recovery/remodeling. Skeletal muscle-derived PICs show significant reparative potential, attenuating cardiac remodelling following transplantation into the infarcted myocardium. PICs can be easily sourced from skeletal muscle and therefore show promise as a potential cell candidate for supporting the reparative and regenerative effects of cell therapie

Role of bulk and surface phonons in the decay of metal surface states

We present a comprehensive theoretical investigation of the electron-phonon contribution to the lifetime broadening of the surface states on Cu(111) and Ag(111), in comparison with high-resolution photoemission results. The calculations, including electron and phonon states of the bulk and the surface, resolve the relative importance of the Rayleigh mode, being dominant for the lifetime at small hole binding energies. Including the electron-electron interaction, the theoretical results are in excellent agreement with the measured binding energy and temperature dependent lifetime broadening.Comment: 4 pages, 3 figure

Lifetime of d-holes at Cu surfaces: Theory and experiment

We have investigated the hole dynamics at copper surfaces by high-resolution angle-resolved photoemission experiments and many-body quasiparticle GW calculations. Large deviations from a free-electron-like picture are observed both in the magnitude and the energy dependence of the lifetimes, with a clear indication that holes exhibit longer lifetimes than electrons with the same excitation energy. Our calculations show that the small overlap of d- and sp-states below the Fermi level is responsible for the observed enhancement. Although there is qualitative good agreement of our theoretical predictions and the measured lifetimes, there still exist some discrepancies pointing to the need of a better description of the actual band structure of the solid.Comment: 15 pages, 7 figures, 1 table, to appear in Phys. Rev.

When the going gets tough the beautiful get going: aesthetic appeal facilitates task performance.

The current studies examined the effect of aesthetic appeal on performance. According to one hypothesis, appeal would lead to overall decrements or enhancements in performance [e.g. Sonderegger & Sauer, (Applied Ergonomics, 41, 403-410, 2010)]. Alternatively, appeal might influence performance only in problem situations, such as when the task is difficult [e.g. Norman, (2004)]. The predictions of these hypotheses were examined in the context of an icon search-and-localisation task. Icons were used because they are well-defined stimuli and pervasive to modern everyday life. When search was made difficult using visually complex stimuli (Experiment 1), or abstract and unfamiliar stimuli (Experiment 2), icons that were appealing were found more quickly than their unappealing counterparts. These findings show that in a low-level visual processing task, with demand characteristics related to appeal eliminated, appeal can influence performance, especially under duress