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The plasmonics of two–dimensional materials, such as graphene, has become an important field over the past decade. The active tunability of graphene via electrical gating or chemical doping has generated a great deal of excitement among engineers seeking sensing devices. Consequently there is significant demand for robust and highly accurate computational capabilities which can simulate such materials. The class of High–Order Perturbation of Surfaces methods have proven to be particularly appropriate for this purpose. In this contribution we describe our recent efforts to utilize both Dirichlet–Neumann Operators and Impedance–Impedance Operators in these schemes. In addition, we present detailed numerical results which not only validate our simulations using the Method of Manufactured Solutions, but we also describe Localized Surface Plasmon Resonances in graphene nanotubes enclosing rod–shaped dielectric materials. [ABSTRACT FROM AUTHOR]

Thomson and MacMillan's paper What's wrong with osteopathy? has understandably caused some consternation within the profession. In this commentary I want to support the intent of their argument, but also suggest they do not go far enough. Western healthcare is entering a post-professional era which will profoundly affect every profession's identity and social purpose. The effects of late capitalism on the atomisation of the body, the unbundling of goodness and expertise, and the transformative effects of digital technologies are not commonly discussed issues in osteopathy, but they are becoming central concerns for any profession looking to adapt to future healthcare. In this essay, I briefly outline the challenges of post-professionalism and explore some of the reactions we have already seen in other professions like physiotherapy. Four response archetypes are identified: watching and waiting, a modern heritage approach, professional renaissance, and hybrid professionalism that, I argue, lies behind Thomson and MacMillan's proposition. All four of these approaches are shown to have significant limitations, so the paper ends with some suggestions for a direction that might be a better way forward for osteopathy. [ABSTRACT FROM AUTHOR]

The scattering of linear electromagnetic waves by a layered structure is a central model in many problems of engineering interest. In this contribution, we focus on the interaction of visible and near–visible radiation with periodic structures on the micron or nanometer scales which are relevant for many applications in nanoplasmonics. The fabrication of such structures is extremely difficult and costly, and even the most sophisticated laboratories have difficulty measuring the dimensions of gratings they have constructed. We present a new, extremely rapid and robust, identification algorithm for providing precisely this information. It is built upon a Nonlinear Least Squares framework, and implemented with a High–Order Perturbation of Surfaces methodology which is orders of magnitude faster than volumetric solvers, while outperforming surface methods (such as Boundary Integral Methods) for the geometries we consider here. In addition to a full derivation and specification of the algorithm, we also support our claims with a number of illustrative simulations. [ABSTRACT FROM AUTHOR]

The accurate simulation of linear electromagnetic scattering by diffraction gratings is crucial in many technologies of scientific and engineering interest. In this contribution we describe a High-Order Perturbation of Surfaces (HOPS) algorithm built upon a class of Integral Equations due to the analysis of Fokas and collaborators, now widely known as the Unified Transform Method. The unknowns in this formalism are boundary quantities (the electric field and current at the layer interface) which are an order of magnitude fewer than standard volumetric approaches such as Finite Differences and Finite Elements. With detailed numerical experiments we show the efficiency, fidelity, and high-order accuracy one can achieve with an implementation of this algorithm. [ABSTRACT FROM AUTHOR]

Abstract: In this contribution we study the spectrum of periodic traveling gravity waves on a two-dimensional fluid of finite depth. We extend the stable and highly accurate method of Transformed Field Expansions to the finite depth case in the presence of both simple and repeated eigenvalues, and then numerically simulate the changes in the spectrum as the wave amplitude is increased. We also calculate explicitly the first non-zero correction to the flat-water spectrum, which we observe to accurately predict the stability (or instability) for all amplitudes within the disc of analyticity of the spectrum. In addition to computations of the spectrum, we also compute the radius of the disc of analyticity of the spectrum—the amplitude boundary beyond which neither the asymptotics nor the TFE method is applicable. We observe an instability which is analytically connected to the flat state for . [Copyright &y& Elsevier]

Abstract: Neuronal populations throughout the brain achieve levels of synchronous electrophysiological activity as a consequence of both normal brain function as well as during pathological states such as in epileptic seizures. Understanding this synchrony and being able to quantitatively assess the dynamics with which neuronal oscillators across the brain couple their activity is a critical component toward decoding such complex behavior. Commonly applied techniques to resolve relationships between oscillators typically make assumptions of linearity and stationarity that are likely not to be valid for complex neural signals. In this study, intracranial electroencephalographic activity was recorded bilaterally in both hippocampi and in anteromedial thalamus of rat under normal conditions and during hypersynchronous seizure activity induced by focal injection of the epileptogenic agent kainic acid. Nonlinear oscillators were first extracted using empirical mode decomposition. The technique of eigenvalue decomposition was used to assess global phase synchrony of the highest energy oscillators. The Hilbert analytical technique was then used to measure instantaneous phase synchrony of these oscillators as they evolved in time. To test the reliability of this method, we first applied it to a system of two coupled Rössler attractors under varying levels of coupling with small frequency mismatch. The application of these analytical techniques to intracranially recorded brain signals provides a means for assessing how complex oscillatory behavior in the brain evolves and changes during both normal activity and as a consequence of diseased states without making restrictive and possibly erroneous assumptions of the linearity and stationarity of the underlying oscillatory activity. [Copyright &y& Elsevier]

Abstract: This synthesis examines international opportunities for utilizing biomass for energy at several different scales, with an emphasis on larger scale electrical power generation at stand-alone facilities as well as smaller scale thermal heating applications such as those at governmental, educational, or other institutional facilities. It identifies barriers that can inhibit bioenergy applications, and considers international cases of successful bioenergy production with a focus on Europe and Brazil. Based on the review of international bioenergy applications, important ecosystem service issues having relevance to western U.S. forests are discussed, including hazardous fuel reduction, community development, and sustainability of the wood products industry. [Copyright &y& Elsevier]

Abstract: The detection of ocean bathymetry is one of the most important and difficult problems in oceanography. On the theoretical side it is a classical inverse problem which features severe ill-posedness found in similar problems from a wide array of applied sciences. From a practical standpoint, standard procedures based upon “Underwater Acoustics” are quite dangerous and expensive as the desired surface is separated from measuring devices by (at least) the entire ocean layer providing a very hostile and unpredictable sampling environment. In this research we take a rather different approach to this inverse problem as we rely upon nonlinear features of the governing fluid mechanical equations to detect information about the ocean bathymetry. This is also in contrast to similar methods in the literature which rely solely upon the variations in the dispersion relation. Using a formulation of the water wave problem due to Zakharov, and Craig and Sulem, and the analyticity of the “Dirichlet–Neumann operator” we find surprisingly convenient formulas involving the ocean bathymetry. Of course, these formulas are ill-conditioned and nonlinear, however, we have found that application of standard techniques from the theory of inverse problems allow us to predict the shape of bottom topography with excellent precision. [Copyright &y& Elsevier]

Abstract: The Euler equations of free-surface ocean dynamics constitute a model of central importance in fluid mechanics due to the wide range of physical phenomena they are intended to represent, from shoaling and breaking of waves in nearshore regions to energy and momentum transport in the open ocean. From a mathematical perspective, these equations present rather unique challenges for analysis and simulation as they couple the subtleties of nonlinear wave equations (balancing nonlinearity with dispersion in the absence of dissipation) to the difficulties of free-boundary problems. In this paper a new, stable high-order boundary perturbation algorithm for the numerical simulation of traveling water waves is described. Its performance is compared to that of classical surface deformation algorithms and it is shown that the new scheme displays significantly enhanced conditioning properties and a lower computational cost, which enable very accurate predictions of physical observables such as velocity, energy, height/steepness, and shape. [Copyright &y& Elsevier]

Abstract: The kinetic properties for the uptake, storage and release of Ca2+ from isolated mitochondria accurately predict the behaviour of the organelles within the intact cell. While the steady-state cycling of Ca2+ across the inner membrane between independent uptake and efflux pathways seems at first sight to be symmetrical, the distinctive kinetics of the uniporter, which is highly dependent on external free Ca2+ concentration and the efflux pathway, whose activity is clamped over a wide range of total matrix Ca2+ by the solubility of the calcium phosphate complex provide a mechanism whereby mitochondria reversibly sequester transient elevations in cytoplasmic Ca2+. Under non-stimulated conditions, the same transport processes can regulate matrix Ca2+ concentrations and hence citric acid cycle activity. [Copyright &y& Elsevier]

This paper discusses the bifurcation theory for the equations for traveling surface water waves, based on the formulation of Zakharov [58] and of Craig and Sulem [15] in terms of integro-differential equations on the free surface. This theory recovers the well-known picture of bifurcation curves of Stokes progressive wavetrains in two-dimensions, with the bifurcation parameter being the phase velocity of the solution. In three dimensions the phase velocity is a two-dimensional vector, and the resulting bifurcation equations describe two-dimensional bifurcation surfaces, with multiple intersections at simple bifurcation points. The integro-differential formulation on the free surface is posed in terms of the Dirichlet–Neumann operator for the fluid domain. This lends itself naturally to numerical computations through the fast Fourier transform and surface spectral methods, which has been implemented in Nicholls [32]. We present a perturbation analysis of the resulting bifurcation surfaces for the three-dimensional problem, some analytic results for these bifurcation problems, and numerical solutions of the surface water waves problem, based on a numerical continuation method which uses the spectral formulation of the problem in surface variables. Our numerical results address the problem in both two and three dimensions, and for both the shallow and deep water cases. In particular we describe the formation of steep hexagonal traveling wave patterns in the three-dimensional shallow water regime, and their transition to rolling waves, on high aspect ratio rectangular patterns as the depth increases to infinity. [Copyright &y& Elsevier]