Predicting Climate-Driven Coastlines With a Simple and Efficient Multiscale Model

Ocean-basin-scale climate variability produces shifts in wave climates and water levels affecting the coastlines of the basin. Here we present a hybrid shoreline change?foredune erosion model (A COupled CrOss-shOre, loNg-shorE, and foreDune evolution model, COCOONED) intended to inform coastal planning and adaptation. COCOONED accounts for coupled longshore and cross-shore processes at different timescales, including sequencing and clustering of storm events, seasonal, interannual, and decadal oscillations by incorporating the effects of integrated varying wave action and water levels for coastal hazard assessment. COCOONED is able to adapt shoreline change rates in response to interactions between longshore transport, cross-shore transport, water level variations, and foredune erosion. COCOONED allows for the spatial and temporal extension of survey data using global data sets of waves and water levels for assessing the behavior of the shoreline at multiple time and spatial scales. As a case study, we train the model in the period 2004?2014 (11 years) with seasonal topographic beach profile surveys from the North Beach Sub-cell (NBSC) of the Columbia River Littoral Cell (Washington, USA).We explore the shoreline response and foredune erosion along 40 km of beach at several timescales during the period 1979?2014 (35 years), revealing an accretional trend producing reorientation of the beach, cross-shore accretional, and erosional periods through time (breathing) and alternating beach rotations that are correlated with climate indices.J. A. A. Antolínez and F. J. Méndez acknowledge the support of the Spanish “Ministerio de Economia y Competitividad” under Grant BIA2014-59643-R

Bostonia. Volume 11

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

Resonances in a spring-pendulum: algorithms for equivariant singularity theory

A spring-pendulum in resonance is a time-independent Hamiltonian model system for formal reduction to one degree of freedom, where some symmetry (reversibility) is maintained. The reduction is handled by equivariant singularity theory with a distinguished parameter, yielding an integrable approximation of the Poincaré map. This makes a concise description of certain bifurcations possible. The computation of reparametrizations from normal form to the actual system is performed by Gröbner basis techniques.

High-Power Gallium Nitride HIFU Transmitter with Integrated Real-Time Current and Voltage Measurement

High-Intensity Focused Ultrasound (HIFU) therapy provides a non-invasive technique with which to destroy cancerous tissue without using ionizing radiation. To drive large single-element HIFU transducers, ultrasound transmitters capable of delivering high powers at relevant frequencies are required. The acoustic power delivered to a transducers focal region will determine the treated area, and due to safety concerns and intervening layers of attenuation, control of this output power is critical. A typical setup involves large inefficient linear power amplifiers to drive the transducer. Switched mode transmitters allow for a more compact drive system with higher efficiencies, with multi-level transmitters allowing control over the output power. Real-time monitoring of power delivered can avoid damage to the transducer and injury to patients due to over treatment, and allow for precise control over the output power. This study demonstrates a transformer-less, high power switched mode transmit transmitter based on Gallium-Nitride (GaN) transistors that is capable of delivering peak powers up to 1.8 kW at up to 600 Vpp, while operating at frequencies from DC to 5 MHz. The design includes a 12 bit 16 MHz floating Current/Voltage (I-V) measurement circuit to allow real-time high-side monitoring of the power delivered to the transducer allowing use with multi-element transducers

Error reduction therapy in reducing struggle and grope behaviours in apraxia of speech

We report an intervention study focused on the speech production difficulties present in acquired apraxia of speech (AOS). The intervention was a self-administered computer therapy that targeted whole word production and incorporated error reduction strategies. The effectiveness of the therapy was contrasted to that of a visuospatial sham computer program, and performance across treated words, and two sets of matched words, was assessed. Two groups of participants completed the study which employed a two-phase cross-over treatment design. Participants were randomly assigned to a speech first or sham first condition. Treatments were administered for six weeks, with a four week rest between interventions. Participants were assessed five times in total; twice at baseline, once following each of the intervention phases, and once following a lapse of eight weeks after the end of the second phase of intervention. The occurrence of accurate word production and speech characterised by struggle and groping behaviours was recorded on a repetition task. Participants showed significant gains in speech accuracy and fluency, and reductions in articulatory groping and struggle behaviours following the use of the speech program. These gains were largely maintained once the therapy was withdrawn

Cold Bose gases with large scattering lengths

We calculate the energy and condensate fraction for a dense system of bosons interacting through an attractive short range interaction with positive s-wave scattering length $a$. At high densities, $n>>a^{-3}$, the energy per particle, chemical potential, and square of the sound speed are independent of the scattering length and proportional to $n^{2/3}$, as in Fermi systems.Comment: 4 pages, 3 figure

A multi-centre, parallel group superiority trial of silk therapeutic clothing compared to standard care for the management of eczema in children (CLOTHES Trial): study protocol for a randomised controlled trial

Background - Eczema is a chronic, itchy skin condition that can have a large impact on the quality of life of patients and their families. People with eczema are often keen to try out non-pharmacological therapies like silk therapeutic garments that could reduce itching or the damage caused by scratching. However, the effectiveness and cost-effectiveness of these garments in the management of eczema has yet to be proven. The CLOTHES Trial will test the hypothesis that ‘silk therapeutic garments plus standard eczema care’ is superior to ‘standard care alone’ for children with moderate to severe eczema.Methods/Design - Parallel group, observer-blind, pragmatic, multi-centre randomised controlled trial of 6 months’ duration. Three hundred children aged 1 to 15 years with moderate to severe eczema will be randomised (1:1) to receive silk therapeutic garments plus standard eczema care, or standard eczema care alone. Primary outcome is eczema severity, as assessed by trained and blinded investigators at 2, 4 and 6 months (using the Eczema Area and Severity Index (EASI)). Secondary outcomes include: patient-reported eczema symptoms (collected weekly for 6 months to capture long-term control); global assessment of severity; quality of life of the child, family and main carer; use of standard eczema treatments (emollients, corticosteroids applied topically, calcineurin inhibitors applied topically and wet wraps); frequency of infections; and cost-effectiveness. The acceptability and durability of the clothing will also be assessed, as will adherence to wearing the garments. A nested qualitative study will assess the views of a subset of children wearing the garments and their parents, and those of healthcare providers and commissioners. Randomisation uses a computer-generated sequence of permuted blocks of randomly varying size, stratified by recruiting hospital and child’s age ( 5 years), and concealed using a secure web-based system. The sequence of treatment allocations will remain concealed until randomisation and data collection are complete.Recruitment is taking place from November 2013 to May 2015, and the trial will be completed in 2016. Full details of results will be published in the National Institute for Health Research Journal series.Trial registration - Current Controlled Trials ISRCTN77261365 (registered 11 November 2013)

Two-body correlations in N-body boson systems

We formulate a method to study two-body correlations in a system of N identical bosons interacting via central two-body potentials. We use the adiabatic hyperspherical approach and assume a Faddeev-like decomposition of the wave function. For a fixed hyperradius we derive variationally an optimal integro-differential equation for hyperangular eigenvalue and wave function. This equation reduces substantially by assuming the interaction range much smaller than the size of the N-body system. At most one-dimensional integrals then remain. We view a Bose-Einstein condensate pictorially as a structure in the landscape of the potential given as a function of the one-dimensional hyperradial coordinate. The quantum states of the condensate can be located in one of the two potential minima. We derive and discuss properties of the solutions and illustrate with numerical results. The correlations lower the interaction energy substantially. The new multi-body Efimov states are solutions independent of details of the two-body potential. We compare with mean-field results and available experimental data.Comment: 19 pages (RevTeX4), 13 figures (latex). Journal-link: http://pra.aps.org