Wigner-Crystal Formulation of Strong-Coupling Theory for Counter-ions Near Planar Charged Interfaces

We present a new analytical approach to the strong electrostatic coupling regime (SC), that can be achieved equivalently at low temperatures, high charges, low dielectric permittivity etc. Two geometries are analyzed in detail: one charged wall first, and then, two parallel walls at small distances, that can be likely or oppositely charged. In all cases, one type of mobile counter-ions only is present, and ensures electroneutrality (salt free case). The method is based on a systematic expansion around the ground state formed by the two-dimensional Wigner crystal(s) of counter-ions at the plate(s). The leading SC order stems from a single-particle theory, and coincides with the virial SC approach that has been much studied in the last 10 years. The first correction has the functional form of the virial SC prediction, but the prefactor is different. The present theory is free of divergences and the obtained results, both for symmetrically and asymmetrically charged plates, are in excellent agreement with available data of Monte-Carlo simulations under strong and intermediate Coulombic couplings. All results obtained represent relevant improvements over the virial SC estimates. The present SC theory starting from the Wigner crystal and therefore coined Wigner SC, sheds light on anomalous phenomena like the counter-ion mediated like-charge attraction, and the opposite-charge repulsion

Performance of the Colorado wind-profiling network, part 1.5A

The Wave Propagation Laboratory (WPL) has operated a network of radar wind Profilers in Colorado for about 1 year. The network consists of four VHF (50-MHz) radars and a UHF (915-MHz) radar. The Platteville VHF radar was developed by the Aeronomy Laboratory (AL) and has been operated jointly by WPL and AL for several years. The other radars were installed between February and May 1983. Experiences with these radars and some general aspects of tropospheric wind measurements with Doppler radar are discussed

Vortex Solutions in Two-Higgs-Doublet Systems

We analyze the existence of string-like defects in a two-Higgs-doublet system having $SU(2) \times U(1)_Y \times U(1)_{Y^{\prime}}$ as gauge group. We are able to show that, when certain relations among the parameters hold, these configurations satisfy a set of first order differential equations (Bogomol'nyi equations) and their energy is proportional to their topological charge.}Comment: 9 page

Photon Channelling in Foams

Experiments by Gittings, Bandyopadhyay, and Durian [Europhys. Lett.\ \textbf{65}, 414 (2004)] demonstrate that light possesses a higher probability to propagate in the liquid phase of a foam due to total reflection. The authors term this observation photon channelling which we investigate in this article theoretically. We first derive a central relation in the work of Gitting {\em et al.} without any free parameters. It links the photon's path-length fraction $f$ in the liquid phase to the liquid fraction $\epsilon$. We then construct two-dimensional Voronoi foams, replace the cell edges by channels to represent the liquid films and simulate photon paths according to the laws of ray optics using transmission and reflection coefficients from Fresnel's formulas. In an exact honeycomb foam, the photons show superdiffusive behavior. It becomes diffusive as soon as disorder is introduced into the foams. The dependence of the diffusion constant on channel width and refractive index is explained by a one-dimensional random-walk model. It contains a photon channelling state that is crucial for the understanding of the numerical results. At the end, we shortly comment on the observation that photon channelling only occurs in a finite range of $\epsilon$.Comment: 9 pages, minor change

Developing theory in motivational interviewing: academic and practitioner perspectives from MICBT integration

Motivational Interviewing (MI) and Cognitive Behaviour Therapy (CBT) are both evidence based psychosocial interventions. Motivational interviewing has not sought to develop its own comprehensive theory (Miller & Rollnick, 2012) although it has developed hypotheses on why MI works. This project has looks at what an integration of these two approaches can tell us about motivational interviewing’s theory, hypothesised mechanisms of action and efficacy. It has set out to examine and explore existing theory through qualitative research. This included Semi structured interviews with researchers and practitioners who are experts in the integration of MI and CBT (MICBT). Their views and existing literature were used develop understanding about MI efficacy. A critical realist philosophical framework and Theoretical Thematic analysis was used to explore and test MI theory. A number of themes around hypothesised mechanisms and MI theory emerged from both sets of participants. These included psychological safety, alliance, responding to resistance, acceptance, compassion and positive emotion. A relational rather than a technical practice was emphasised and the theory relating to that observed. Theory around Power, its negative and positive operation in people’s lives arose frequently; as did hypothesised mechanisms relating to power differentials and MI as a ‘power yielding’ approach. Building on insights from evolutionary theory, links were made to a more detailed consideration of the effects of social context on research, practice and the ability of individuals to make change. This project challenges a narrow-individualised approach to research and intervention, emphasising the need to take into account the effects of social inequality and individual social circumstances. The project has illustrated some of the reality of translating theory into real-world practice and suggests expanding MI theory so that it is more contextualised. The centrality of understanding power and power structures may be a useful addition to an understanding of why MI works. An increased awareness of social context and its impacts raise questions about how individual and societal level interventions could work together to improve health behaviour change. Finally, a number of suggestions for future research are made, including that individualised interventions need to be evaluated in real-world services, with direct consultation of and involvement of service users

ChromatoShiny: an interactive R/Shiny App for plotting chromatography profiles [version 2; peer review: 2 approved]

BackgroundUnicorn™ software on Äkta liquid chromatography instruments outputs chromatography profiles of purified biological macromolecules. While the plots generated by the instrument software are very helpful to inspect basic chromatogram properties, they lack a range of useful annotation, customization and export options.MethodsWe use the R Shiny framework to build an interactive app that facilitates the interpretation of chromatograms and the generation of figures for publications.ResultsThe app allows users to fit a baseline, to highlight selected fractions and elution volumes inside or under the plot (e.g. those used for downstream biochemical/biophysical/structural analysis) and to zoom into the plot. The app is freely available at https://ChromatoShiny.bio.ed.ac.uk.ConclusionsIt requires no programming experience, so we anticipate that it will enable chromatography users to create informative, annotated chromatogram plots quickly and simply.FPLC instruments used to purify macromolecules output the UV intensity values over the elution volume. However, the software used with these instruments is not usually used to generate the figures for publication. To facilitate the analysis of chromatograms and generation of publication figures, we developed a web app which is possible to use without programming skills. The app is working on Äkta .txt files and is able to fit a baseline, to highlight fractions on and under the plot and to zoom into the plot. The app is designed for Äkta instruments, but the data from other softwares can be entered in the provided template and plotted accordingly. The app is well suited for plotting many similar plots. The plots can be downloaded in various formats. The app is equipped with instructions and has a user friendly interface. We hope that the app will become a helpful tool for displaying chromatograms from various FPLC softwares

Open/Closed String Topology and Moduli Space Actions via Open/Closed Hochschild Actions

In this paper we extend our correlation functions to the open/closed case. This gives rise to actions of an open/closed version of the Sullivan PROP as well as an action of the relevant moduli space. There are several unexpected structures and conditions that arise in this extension which are forced upon us by considering the open sector. For string topology type operations, one cannot just consider graphs, but has to take punctures into account and one has to restrict the underlying Frobenius algebras. In the moduli space, one first has to pass to a smaller moduli space which is closed under open/closed duality and then consider covers in order to account for the punctures

Anomalous temperature dependence of surface tension and capillary waves at liquid gallium

The temperature dependence of surface tension \gamma(T) at liquid gallium is studied theoretically and experimentally using light scattering from capillary waves. The theoretical model based on the Gibbs thermodynamics relates the temperature derivative of \gamma to the surface excess entropy -\Delta S. Although capillary waves contribute to the surface entropy with a positive sign the effect of dipole layer on \Delta S is negative. Experimental data collected at a free Ga surface in the temperature range from 30 to 160 C show that the temperature derivative of the tension changes sign near 100 C.Comment: 11 pages, 1 Postscript figure, submitted to J. Phys.