Learning to Produce Speech with an Altered Vocal Tract: The Role of Auditory Feedback

Modifying the vocal tract alters a speaker’s previously learned acoustic–articulatory relationship. This study investigated the contribution of auditory feedback to the process of adapting to vocal-tract modifications. Subjects said the word /tɑs/ while wearing a dental prosthesis that extended the length of their maxillary incisor teeth. The prosthesis affected /s/ productions and the subjects were asked to learn to produce ‘‘normal’’ /s/’s. They alternately received normal auditory feedback and noise that masked their natural feedback during productions. Acoustic analysis of the speakers’ /s/ productions showed that the distribution of energy across the spectra moved toward that of normal, unperturbed production with increased experience with the prosthesis. However, the acoustic analysis did not show any significant differences in learning dependent on auditory feedback. By contrast, when naive listeners were asked to rate the quality of the speakers’ utterances, productions made when auditory feedback was available were evaluated to be closer to the subjects’ normal productions than when feedback was masked. The perceptual analysis showed that speakers were able to use auditory information to partially compensate for the vocal-tract modification. Furthermore, utterances produced during the masked conditions also improved over a session, demonstrating that the compensatory articulations were learned and available after auditory feedback was removed

Microgrids & District Energy: Pathways To Sustainable Urban Development

A microgrid is an energy system specifically designed to meet some of the energy needs of a group of buildings, a campus, or an entire community. It can include local facilities that generate electricity, heating, and/or cooling; store energy; distribute the energy generated; and manage energy consumption intelligently and in real time. Microgrids enable economies of scale that facilitate local production of energy in ways that can advance cost reduction, sustainability, economic development, and resilience goals. As they often involve multiple stakeholders, and may encompass numerous distinct property boundaries, municipal involvement is often a key factor for successful implementation. This report provides an introduction to microgrid concepts, identifies the benefits and most common road blocks to implementation, and discusses proactive steps municipalities can take to advance economically viable and environmentally superior microgrids. It also offers advocacy suggestions for municipal leaders and officials to pursue at the state and regional level. The contents are targeted to municipal government staff but anyone looking for introductory material on microgrids should find it useful

Otolith function in human subjects: Perception of motion, reflex eye movements and vision during linear interaural acceleration

The thesis investigates how the otolith organs of the vestibular system, specifically the utricles, assist motion perception and aid visual stabilization, during translational lateral whole-body acceleration. It was found that high gradients of acceleration facilitate the detection of motion and that, for low acceleration gradients, motion perception in normal subjects relies on a 'velocity' threshold detection process. Experiments in patients without vestibular function indicated that, for the stimuli employed, the somatosensory system could be as sensitive to linear motion as the vestibular system. The interaction between the horizontal linear vestibulo-ocular reflex (LVOR) and visual context was characterized in the following experiments. Subjects were accelerated transiently in darkness, or while viewing earth-fixed or head-fixed targets. From onset, the eye velocity response to head translation was enhanced with acceleration level and target proximity, but was only slightly reduced by fixation of head-fixed targets. This suggested that the gain of the LVOR pathway was adjusted before or immediately after motion onset by a parameter depending mainly on viewing distance and less on the knowledge of probable relative target motion. For high relative target velocities, LVORs improved ocular fixation over what would be attained by pursuit alone, although fully compensatory eye movements were not always produced. The LVORs of patients who underwent unilateral vestibular deafferentation suggested that the utricular area generating transaural LVORs is the macular region lateral to the striola. Psychophysical experiments based on a reading task established the functional role of the LVOR for stabilising vision during high-frequency sinusoidal whole-body acceleration. Unlike normal subjects, visual acuity in patients without vestibular function was not better during self-motion than during display oscillation. Finally, the LVOR interaction with canal-ocular reflexes was studied using isolated and combined translational/rotational stimuli. The results showed that, shortly after motion onset, canal stimulation enhances the LVOR evoked by head translation

Energy, carbon dioxide and consumer choice

Analysis of need:If the threat of climate change because of anthropogenic greenhouse gas emission is accepted, then important economic, technological and social adaptations will be needed to avert the threat. Numerous studies have looked at the technological and economic strategies for the control of one of the principal greenhouse gases, carbon dioxide: few look at how control might be achieved through social adaptation in terms of changes in behaviour or lifestyle. This study is an attempt to look at the potential reduction in energy use and carbon emission due to relatively minor changes in lifestyle.The global carbon problem:The scientific consensus is that to limit the rate and final increase in global temperature, annual carbon dioxide emission will have to be reduced by 60% to 80% as compared to 1990 by around the end of the next century. During this time, the world population may more than double. If it is assumed that equity in terms of per capita carbon emissions will eventually be achieved, then the per capita carbon emissions of most rich countries have to fall by over 90% from current levels. The limits of technical measures:Conservation, energy efficiency and renewable energy sources are vital elements in strategies which aim to reduce carbon dioxide emissions. However, these technical measures run into increasing marginal economic and environmental cost with increasing levels of implementation. In practical terms, this makes it difficult to reach reductions of over 90% with these means, at least with known technologies. It is therefore necessary to appraise how changes in people's behaviour and lifestyle might contribute to carbon emission control.Lifestyle change:Certain aspects of lifestyle are predicated on the consumption of goods and services, the provision of which has a physical impact on the environment. The enjoyment of warm buildings and private transport are examples of such. An analysis of the UK shows that minor lifestyle changes including wearing better clothes and buying smaller slower cars could reduce carbon emission by around 25% quite rapidly. A proportional reduction of this order may be made even if quite high levels of energy conservation are assumed. When such lifestyle changes are applied to other rich countries, similar emission reductions may be made, and lifestyle takes on global significance in terms of an element in carbon emission control strategies. A separate study is needed to detail how people's lifestyle and general patterns of consumption might be influenced. This study does however identify some of the approaches which might be taken