Interfacial friction between semiflexible polymers and crystalline surfaces

The results obtained from molecular dynamics simulations of the friction at an interface between polymer melts and weakly attractive crystalline surfaces are reported. We consider a coarse-grained bead-spring model of linear chains with adjustable intrinsic stiffness. The structure and relaxation dynamics of polymer chains near interfaces are quantified by the radius of gyration and decay of the time autocorrelation function of the first normal mode. We found that the friction coefficient at small slip velocities exhibits a distinct maximum which appears due to shear-induced alignment of semiflexible chain segments in contact with solid walls. At large slip velocities the decay of the friction coefficient is independent of the chain stiffness. The data for the friction coefficient and shear viscosity are used to elucidate main trends in the nonlinear shear rate dependence of the slip length. The influence of chain stiffness on the relationship between the friction coefficient and the structure factor in the first fluid layer is discussed.Comment: 31 pages, 12 figure

Updating the CASE database: analysis of original approach

The CASE database of research evidence is a unique and comprehensive resource for those working in the field of culture and sport. The database currently holds the records of over 5,500 studies on the drivers, impact and value of engagement in culture and sport. In order to maintain the value of the CASE database, a strategy will be needed to regularly update the database. The update strategy should be informed by the knowledge and experience gained from the search and selection process initially used to populate the CASE database. This paper analyses the original search strategy carried out by the EPPI-Centre to aid and inform the development of the update strategy

Long-Lived Superheavy Particles in Dynamical Supersymmetry-Breaking Models in Supergravity

Superheavy particles of masses $\simeq 10^{13}-10^{14} GeV$ with lifetimes $\simeq 10^{10}-10^{22} years$ are very interesting, since their decays may account for the ultra-high energy (UHE) cosmic rays discovered beyond the Greisen-Zatsepin-Kuzmin cut-off energy $E \sim 5 \times 10^{10} GeV$. We show that the presence of such long-lived superheavy particles is a generic prediction of QCD-like SU(N_c) gauge theories with N_f flavors of quarks and antiquarks and the large number of colors N_c. We construct explicit models based on supersymmetric SU(N_c) gauge theories and show that if the dynamical scale $\Lambda \simeq 10^{13}-10^{14} GeV$ and N_c = 6-10 the lightest composite baryons have the desired masses and lifetimes to explain the UHE cosmic rays. Interesting is that in these models the gaugino condensation necessarily occurs and hence these models may play a role of so-called hidden sector for supersymmetry breaking in supergravity.Comment: 13 pages, Late

Workplace-based learning for undergraduate and pre-registration healthcare professionals: A systematic map of the UK research literature 2003-2013

What do we want to know? What is the nature of the research on workplace-based learning for undergraduate and pre-registration healthcare professionals in the UK? How many studies are there and what do they focus on? Who wants to know? The map was funded by the Higher Education Academy, UCL Institute of Education, University College London, and the Association for the Study of Medical Education. Workplace based learning is a key component of healthcare professionals education and training and is therefore a key concern of educators, professional bodies, professional regulators, the NHS and Health Education England. What did we find? We identified 117 UK studies about workplace-based learning for undergraduate/pre-registration healthcare students published between 2003 and 2013. The majority of studies (n = 111) focused on students views or experiences of workplace-based learning. Very few studies (n= 6) investigated the impacts of workplace-based learning (using quantitative measurements of change in student attitudes, knowledge or skill). There were no studies that measured impacts on organisational practice or patient/client outcomes. The highest number of studies focused on nursing students in workplace- based learning (n = 52) and there were relatively fewer studies examining students in medicine (n = 13), dentistry (n = 11) and midwifery (n = 10). Studies of workplace-based learning for students of the allied health professions were also limited in number (e.g. four physiotherapy studies). Eighteen studies focused on workplace-based learning in an inter-professional context. The majority of studies used qualitative data collected using questionnaires and interviews. What are the conclusions? This is the first report, to our knowledge, that systematically identifies and characterises empirical research literature from the UK on workplace-based learning for undergraduate and pre-registration students across multiple healthcare professions and settings. Based on the findings above, strategies for future research should include: Further research in the field of workplace-based learning for undergraduate and pre-registration healthcare professionals; More research that can measure the impact of workplace-based learning (using quantitative, independent outcome measures); In-depth systematic reviews of student or educator views of workplace-based learning in the healthcare professions; More research on workplace-based learning for healthcare professions other than nursing. How did we get these results? This project undertook a rapid systematic map. This approach employs systematic and transparent methods to describe the research field. The map included two main stages: A focused search and screening process to identify relevant literature. Two electronic databases and a selection of websites were searched for studies. A set of inclusion/exclusion criteria were developed in collaboration with the advisory group and used to screen potentially relevant reports. Descriptive narrative mapping of a subset of the relevant studies. A coding tool was developed and applied to all UK studies. This described key elements of the research: the healthcare students participating in the study, the nature of the workplace-based learning, the study methods and the type of findings. As in other systematic maps the actual research findings of individual studies are not reported

The impact of broadband in schools

The report reviews evidence for the impact of broadband in English schools, exploring; Variations in provision in level of broadband connectivity; Links between the level of broadband activity and nationally accessible performance data; Aspects of broadband connectivity and the school environment that contribute to better outcomes for pupils and teachers; Academic and motivational benefits associated with educational uses of this technology

Channel Flow of a Tensorial Shear-Thinning Maxwell Model: Lattice Boltzmann Simulations

We introduce a nonlinear generalized tensorial Maxwell-type constitutive equation to describe shear-thinning glass-forming fluids, motivated by a recent microscopic approach to the nonlinear rheology of colloidal suspensions. The model captures a nonvanishing dynamical yield stress at the glass transition and incorporates normal-stress differences. A modified lattice-Boltzmann (LB) simulation scheme is presented that includes non-Newtonian contributions to the stress tensor and deals with flow-induced pressure differences. We test this scheme in pressure-driven 2D Poiseuille flow of the nonlinear generalized Maxwell fluid. In the steady state, comparison with an analytical solution shows good agreement. The transient dynamics after startup and cessation of the pressure gradient are studied; the simulation reproduces a finite stopping time for the cessation flow of the yield-stress fluid in agreement with previous analytical estimates

The media and climate change

Progressive voices in the arts and heritage sector have called for a politics of cultural democracy as a means of empowering all to participate in public life. Through a rejection of policies of 'inclusion', they have asked more searching questions about the role culture can play in the fight for social justice. At the same time the sector is preparing for a change of ideological direction, as rumours run rife about what a future Tory government, highly critical of state intervention, will do to the bodies that run the arts and heritage sector. This article looks at the prospects for a radical cultural democracy in the face of these potential political changes

Statistics of Entropy Production in Linearized Stochastic System

We consider a wide class of linear stochastic problems driven off the equilibrium by a multiplicative asymmetric force. The force brakes detailed balance, maintained otherwise, thus producing entropy. The large deviation function of the entropy production in the system is calculated explicitly. The general result is illustrated using an example of a polymer immersed in a gradient flow and subject to thermal fluctuations.Comment: 4 pages, 1 figur

Anomalous lateral diffusion in a viscous membrane surrounded by viscoelastic media

We investigate the lateral dynamics in a purely viscous lipid membrane surrounded by viscoelastic media such as polymeric solutions. We first obtain the generalized frequency-dependent mobility tensor and focus on the case when the solvent is sandwiched by hard walls. Due to the viscoelasticity of the solvent, the mean square displacement of a disk embedded in the membrane exhibits an anomalous diffusion. An useful relation which connects the mean square displacement and the solvent modulus is provided. We also calculate the cross-correlation of the particle displacements which can be applied for two-particle tracking experiments.Comment: 6 pages, 2 figure