Suspension and levitation in nonlinear theories

I investigate stable equilibria of bodies in potential fields satisfying a generalized Poisson equation: divergence[m(grad phi) grad phi]= source density. This describes diverse systems such as nonlinear dielectrics, certain flow problems, magnets, and superconductors in nonlinear magnetic media; equilibria of forced soap films; and equilibria in certain nonlinear field theories such as Born-Infeld electromagnetism. Earnshaw's theorem, totally barring stable equilibria in the linear case, breaks down. While it is still impossible to suspend a test, point charge or dipole, one can suspend point bodies of finite charge, or extended test-charge bodies. I examine circumstances under which this can be done, using limits and special cases. I also consider the analogue of magnetic trapping of neutral (dipolar) particles.Comment: Five pages, Revtex, to appear in Physics Letters

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

Comparing measured and modelled PFOS concentrations in a UK freshwater catchment and estimating emission rates

The lifecycle, sources and fate of perfluorooctane sulfonate (PFOS) continue to generate scientific and political interest, particularly since PFOS was listed by the Stockholm Convention and largely restricted in Europe. It continues to be detected in aquatic environments, with only limited studies into the on-going sources. This paper explores PFOS emissions discharged by the general population into a small catchment comprising two rivers in the UK. A sampling campaign was undertaken to improve our understanding of population-derived PFOS sources from sewage treatment plants (STPs) and in rivers. A corresponding modelling exercise allowed an emission estimate of 13 μg/day/per capita to be derived for the Aire and Calder rivers. PFOS emission was linked to STP discharges bylinear regression of measured and modelled concntrations (R2 = 0.49–0.85). The model was able to accurately estimate the spatial trends of PFOS in the rivers, while predicted concentrations were within a factor of three based on per capita emission values taken from the literature. Measured PFOS concentrations in rivers suggested that emissions from STPs are partially dependent on treatment type, where plants with secondary or tertiary treatment such as activated sludge processes emit less PFOS, possibly due to increased partitioning and retention. With refinements based on the type of treatment at each STP, predictions were further improved. The total PFOS mass discharged annually via rivers from the UK has been estimated to be between 215 and 310 kg, based on the per capita emission range derived in this study

Forces During Bacteriophage DNA Packaging and Ejection

The conjunction of insights from structural biology, solution biochemistry, genetics and single molecule biophysics has provided a renewed impetus for the construction of quantitative models of biological processes. One area that has been a beneficiary of these experimental techniques is the study of viruses. In this paper we describe how the insights obtained from such experiments can be utilized to construct physical models of processes in the viral life cycle. We focus on dsDNA bacteriophages and show that the bending elasticity of DNA and its electrostatics in solution can be combined to determine the forces experienced during packaging and ejection of the viral genome. Furthermore, we quantitatively analyze the effect of fluid viscosity and capsid expansion on the forces experienced during packaging. Finally, we present a model for DNA ejection from bacteriophages based on the hypothesis that the energy stored in the tightly packed genome within the capsid leads to its forceful ejection. The predictions of our model can be tested through experiments in vitro where DNA ejection is inhibited by the application of external osmotic pressure

10Gb/s low-cost directly modulated multi-electrode laser with suppressed thermal wavelength drift for burst-mode upstream transmission in TWDM-PONs

We report on a novel 10Gb/s low-cost multi-electrode DML employed as a very wavelength stable burst-mode source for upstream TWDM-PONs. 10X wavelength drift reduction is achieved compared to conventional DMLs enabling transmission on 100GHz grid

Inspiring STEM undergraduates to tackle the AMR crisis

To address the growing problem of antimicrobial resistance (AMR), it is necessary to invest in, inspire and attract future generations of scientists to this research area. Undergraduate education should be a focus for attention and efforts should be made to ensure that students are afforded opportunities to actively engage with AMR. We illustrate how as a topic AMR provides opportunities to deliver effective research-led teaching in addition to traditional teaching methods. We have used a selection of case studies to illustrate how students can be engaged with AMR using a variety of research-led approaches to develop the required skills for biology-centric students. In addition, we indicate how these skills map to the UK Quality Assurance Framework and the Vision and Change report developed by the American Association for the Advancement of Science

A new predictor-corrector approach for the numerical integration of coupled electromechanical equations

In this paper, a new approach for the numerical solution of coupled electromechanical problems is presented. The structure of the considered problem consists of the low-frequency integral formulation of the Maxwell equations coupled with Newton-Euler rigid-body dynamic equations. Two different integration schemes based on the predictor-corrector approach are presented and discussed. In the first method, the electrical equation is integrated with an implicit single-step time marching algorithm, while the mechanical dynamics is studied by a predictor-corrector scheme. The predictor uses the forward Euler method, while the corrector is based on the trapezoidal rule. The second method is based on the use of two interleaved predictor-corrector schemes: one for the electrical equations and the other for the mechanical ones. Both the presented methods have been validated by comparison with experimental data (when available) and with results obtained by other numerical formulations; in problems characterized by low speeds, both schemes produce accurate results, with similar computation times. When high speeds are involved, the first scheme needs shorter time steps (i.e., longer computation times) in order to achieve the same accuracy of the second one. A brief discussion on extending the algorithm for simulating deformable bodies is also presented. An example of application to a two-degree-of-freedom levitating device based on permanent magnets is finally reported

Amoxicillin and Clavulanate Form Chemically and Immunologically Distinct Multiple Haptenic Structures in Patients

Amoxicillin-clavulanate (AC) is one of the most common causes of drug induced liver injury (DILI). The association between AC-DILI and HLA alleles and the detection of drug-specific T cells in patients with AC-DILI indicate that the adaptive immune system is involved in the disease pathogenesis. In this study, mass spectrometric methods were employed to characterize the antigen formed by AC in exposed patients and the antigenic determinants that stimulate T cells. Amoxicillin formed penicilloyl adducts with lysine residues on human serum albumin (HSA) <i>in vitro</i>, with K190 and K199 being the most reactive sites. Amoxicillin-modified K190 and K199 have also been detected in all patients, and more extensive modification was observed in patients exposed to higher doses of amoxicillin. In contrast, the binding of clavulanic acid to HSA was more complicated. Multiple adducts were identified at high concentrations <i>in vitro</i>, including those formed by direct binding of clavulanic acid to lysine residues, novel pyrazine adducts derived from binding to the degradation products of clavulanic acid, and a cross-linking adduct. Stable adducts derived from formylacetic acid were detected in all patients exposed to the drug. Importantly, analysis of hapten–protein adducts formed in the cell culture medium revealed that the highly drug-specific T-cell responses were likely driven by the markedly different haptenic structures formed by these two drugs. In this study, the unique haptenic structures on albumin in patients formed by amoxicillin and clavulanic acid have been characterized and shown to function as chemically distinct antigens which can stimulate separate, specific T-cell clones

A randomized trial comparing treatments for varicose veins

Supported by a grant from the Health Technology Assessment Programme of the National Institute for Health Research (06/45/02). The Health Services Research Unit is funded by the Chief Scientist Office of the Scottish Government Health Directorate. We thank Janice Cruden for her secretarial support and data management; Gladys McPherson and the programming team at the Centre for Healthcare Randomised Trials; Tracey Davidson, Lynda Constable, Jackie Ellington, Laura Elliott, and Yvonne Fernie for help with scoring the Aberdeen Varicose Vein Questionnaire; Luke Vale and Laura Ternent, our original economists in the group; members of the Project Management Group for their ongoing advice and support of the trial; members of the study team (Graeme MacLennan, Maria Prior, and Denise Bolsover) who contributed to the behavioral recovery component of the trial; the independent members of the trial steering committee (Alun Davies [chair], Ian Loftus, and Jane Nixon) and the data and safety monitoring committee (Gerry Stansby [chair], Winston Banya, and Marcus Flather); and the staff members at recruitment sites (see the Supplementary Appendix) who facilitated recruitment, treatment, and follow-up of trial participants.Peer reviewedPublisher PD