The influence of preconceptions on perceived sound reduction by environmental noise barriers

The paper presents research that answers three main questions: (1) Do preconceptions held about the constituent materials of an environmental noise barrier affect how people perceive the barrier will perform at attenuating noise? (2) Does aesthetic preference influence the perception of how a barrier will perform? (3) Are barriers, which are deemed more aesthetically pleasing, more likely to be perceived as better noise attenuators? In a virtual reality setting with film to improve the contextual realism of the intersensory interaction test, participants were required to compare the perceived effectiveness of five standard 'in-situ' noise barriers, including concrete, timber, metal, transparent acrylic and a vegetative screen. The audio stimulus was held at a constant sound pressure level (SPL), whilst the visual stimulus changed, as the influential factor. As the noise levels projected during the study were held constant, it was possible to attribute the participants' perception of noise attenuation by the barriers, to preconceptions of how the varying barrier material would attenuate noise. There was also an inverse correlation between aesthetics and perception of how a noise barrier would perform. The transparent and deciduous vegetation barriers, judged most aesthetically pleasing, were judged as the least effective at attenuating noise. (c) 2010 Elsevier B.V. All rights reserved

Combined acoustical and visual performance of noise barriers in mitigating the environmental impact of motorways.

This study investigated the overall performance of noise barriers in mitigating environmental impact of motorways, taking into consideration their effects on reducing noise and visual intrusions of moving traffic, but also potentially inducing visual impact themselves. A laboratory experiment was carried out, using computer-visualised video scenes and motorway traffic noise recordings to present experimental scenarios covering two traffic levels, two distances of receiver to road, two types of background landscape, and five barrier conditions including motorway only, motorway with tree belt, motorways with 3 m timber barrier, 5 m timber barrier, and 5 m transparent barrier. Responses from 30 participants of university students were gathered and perceived barrier performance analysed. The results show that noise barriers were always beneficial in mitigating environmental impact of motorways, or made no significant changes in environmental quality when the impact of motorways was low. Overall, barriers only offered similar mitigation effect as compared to tree belt, but showed some potential to be more advantageous when traffic level went high. 5 m timber barrier tended to perform better than the 3 m one at the distance of 300 m but not at 100 m possibly due to its negative visual effect when getting closer. The transparent barrier did not perform much differently from the timber barriers but tended to be the least effective in most scenarios. Some low positive correlations were found between aesthetic preference for barriers and environmental impact reduction by the barriers

Effects of B cells as antigen presenting cells on T cell memory development [abstract]

Abstract only availableThe function of memory T cells is the primary factor in vaccine efficacy. In order to create or improve existing vaccines, an emphasis has been placed on how a T cell decides to become a memory cell. Previous discoveries in our lab suggest that the number of divisions during the initial exposure to the antigen play an important role in the decision. To further our understanding of the T cells decision, we formulated a hypothesis suggesting that the specific type of antigen presenting cell (APC) involved in the initial encounter with the antigen plays an important role in the generation of the CD4 T cell memory pool. To test this, we developed an adoptive T cell transfer model that allows us to study the different potentials of certain APCs for inducing memory. Ovalbumin (OVA) specific T cell receptor transgenic CD4+ T cells are labeled with CFSE, allowing us to visualize cell division. These are then stimulated in vitro with antigen and APCs. Afterwards, cells showing a specific division pattern are transferred into knockout mice that are lacking the ability to stimulate CD4+ T cells. The cells are left in the mice for four months. The host mice are given MHC competent APCs, immunized and memory response determined. Herein, we show the potential for B cell induced T cell memory