The Arcsine law as the limit of the internal DLA cluster generated by Sinai's walk

We identify the limit of the internal DLA cluster generated by Sinai's walk as the law of a functional of a Brownian motion which turns out to be a new interpretation of the Arcsine law.Comment: 10 pages, 1 figur

The strategies that peanut and nut-allergic consumers employ to remain safe when travelling abroad

Copyright @ 2012 Barnett et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The article has been made available through the Brunel Open Access Publishing Fund.Background: An understanding of the management strategies used by food allergic individuals is needed as a prerequisite to improving avoidance and enhancing quality of life. Travel abroad is a high risk time for severe and fatal food allergic reactions, but there is paucity of research concerning foreign travel. This study is the first to investigate the experiences of, and strategies used by peanut and tree nut allergic individuals when travelling abroad. Methods: Thirty-two adults with a clinical history of reaction to peanuts or tree nuts consistent with IgE-mediated allergy participated in a qualitative interview study. Results: Travel abroad was considered difficult with inherent risks for allergic individuals. Many participants recounted difficulties with airlines or restaurants. Inconsistency in managing allergen avoidance by airlines was a particular risk and a cause of frustration to participants. Individuals used a variety of strategies to remain safe including visiting familiar environments, limiting their activities, carrying allergy information cards in the host language, preparing their own food and staying close to medical facilities. Conclusions: Participants used a variety of allergen avoidance strategies, which were mostly extensions or modifications of the strategies that they use when eating at home or eating-out in the UK. The extended strategies reflected their recognition of enhanced risk during travel abroad. Their risk assessments and actions were generally well informed and appropriate. A need for airline policy regarding allergy to be declared and adhered to is needed, as is more research to quantify the true risks of airborne allergens in the cabin. Recommendations arising from our study are presented.This study is funded by the UK Food Standards Agency under project code T07058

The influence of piezoceramic stack location on nonlinear behavior of langevin transducers

Power ultrasonic applications such as cutting, welding, and sonochemistry often use Langevin transducers to generate power ultrasound. Traditionally, it has been proposed that the piezoceramic stack of a Langevin transducer should be located in the nodal plane of the longitudinal mode of vibration, ensuring that the piezoceramic elements are positioned under a uniform stress during transducer operation, maximizing element efficiency and minimizing piezoceramic aging. However, this general design rule is often partially broken during the design phase if features such as a support flange or multiple piezoceramic stacks are incorporated into the transducer architecture. Meanwhile, it has also been well documented in the literature that power ultrasonic devices driven at high excitation levels exhibit nonlinear behaviors similar to those observed in Duffing-type systems, such as resonant frequency shifts, the jump phenomenon, and hysteretic regions. This study investigates three Langevin transducers with different piezoceramic stack locations by characterizing their linear and nonlinear vibrational responses to understand how the stack location influences nonlinear behavior

Management of Forehead Scars

This article provides an overview of scar management within the forehead region. It addresses the unique challenges specific to the treatment of forehead wounds. A logical, stepwise approach is used. A subsite based treatment algorithm is provided along with a review of current best practices. Pertinent case examples are included for demonstration purposes

High Grading Standards Improve Student Performance

Allgemeinbildende Schule, Schulpolitik, Qualifikation, Vereinigte Staaten, General schooling, School policy, Occupational qualification, United States

High Speed Chaos in Optical Feedback System with Flexible Timescales

We describe a new opto-electronic device with time-delayed feedback that uses a Mach-Zehnder interferometer as passive nonlinearity and a semiconductor laser as a current-to-optical-frequency converter. Bandlimited feedback allows tuning of the characteristic time scales of both the periodic and high dimensional chaotic oscillations that can be generated with the device. Our implementation of the device produces oscillations in the frequency range of tens to hundreds of MHz. We develop a model and use it to explore the experimentally observed Andronov-Hopf bifurcation of the steady state and to estimate the dimension of the chaotic attractor.Comment: 7 pages, 6 figures, to be published in IEEE J. Quantum Electro