1,042 research outputs found

    Quantum oscillations in topological superconductor candidate Cu0.25_{0.25}Bi2_2Se3_3

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    Quantum oscillations are generally studied to resolve the electronic structure of topological insulators. In Cu0.25_{0.25}Bi2_2Se3_3, the prime candidate of topological superconductors, quantum oscillations are still not observed in magnetotransport measurement. However, using torque magnetometry, quantum oscillations (the de Hass - van Alphen effect) were observed in Cu0.25_{0.25}Bi2_2Se3_3 . The doping of Cu in Bi2_2Se3_3 increases the carrier density and the effective mass without increasing the scattering rate or decreasing the mean free path. In addition, the Fermi velocity remains the same in Cu0.25_{0.25}Bi2_2Se3_3 as that in Bi2_2Se3_3. Our results imply that the insertion of Cu does not change the band structure of Bi2_2Se3_3.Comment: 5 pages, 4 figure

    Requirements for Developing the Model of Spatial Orientation into an Applied Cockpit Warning System

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    Refinements have been made to a model of spatial disorientation (SD) to improve simulation of acceleration stimuli and visual-vestibular interactions. The improved model has been applied to aviation mishaps. The model is considered a technological countermeasure for SD because it is implemented as prototype software to aid the identification of mishap contributors in a way that should benefit didactic training. There is a more direct way this countermeasure can prevent SD, which is by adapting it for use as part of a cockpit warning system. The idea is to expand the model from one which explains mishaps post-hoc into one that warns pilots proactively whenever they are most likely to experience SD. This report introduces the general requirements that must be met to successfully expand the model for use as a proactive cockpit warning system, as well as the key criteria for determining whether it is effective

    Nano- and micro-scale impact testing of zirconia, alumina and zirconia-alumina duplex optical coatings on glass

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    Optimising the mechanical properties of optical coatings to improve their durability will be critical if they are to be used successfully in harsh environments where they may be subject to degradation by mechanical contact. In this study zirconia, zirconia-alumina duplex and alumina experimental coatings were deposited on soda lime and borosilicate glass and their resistance to repetitive impact under different experimental conditions evaluated in nano- and micro-scale impact tests. The influence of changing probe geometry (sharp and blunt contacts) and applied load on the deformation was studied. Spheroconical indenters were found to be more suitable to study the load sensitivity of the impact response than sharp cube corner indenters. Increased resistance to plastic deformation in the coating-substrate system (H3/E2) proved detrimental to the damage tolerance to the repetitive nano- and micro-impact tests. To compare the deformation behaviour in nano-impact and nano-scratch, tests were performed using the same spheroconical probe, revealing cracking and blistering of the glass substrate in both types of test. The change in probe depth after the first impact was found to be a very useful metric to effectively compare the evolution of surface damage on continued impact in nano- and micro-impact tests at different applied load and probe geometr

    Motion sickness diagnostic criteria: Consensus document of the classification committee of the Bárány society

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    We present diagnostic criteria for motion sickness, visually induced motion sickness (VIMS), motion sickness disorder (MSD), and VIMS disorder (VIMSD) to be included in the International Classification of Vestibular Disorders. Motion sickness and VIMS are normal physiological responses that can be elicited in almost all people, but susceptibility and severity can be high enough for the response to be considered a disorder in some cases. This report provides guidelines for evaluating signs and symptoms caused by physical motion or visual motion and for diagnosing an individual as having a response that is severe enough to constitute a disorder. The diagnostic criteria for motion sickness and VIMS include adverse reactions elicited during exposure to physical motion or visual motion leading to observable signs or symptoms of greater than minimal severity in the following domains: nausea and/or gastrointestinal disturbance, thermoregulatory disruption, alterations in arousal, dizziness and/or vertigo, headache and/or ocular strain. These signs/symptoms occur during the motion exposure, build as the exposure is prolonged, and eventually stop after the motion ends. Motion sickness disorder and VIMSD are diagnosed when recurrent episodes of motion sickness or VIMS are reliably triggered by the same or similar stimuli, severity does not significantly decrease after repeated exposure, and signs/symptoms lead to activity modification, avoidance behavior, or aversive emotional responses. Motion sickness/MSD and VIMS/VIMSD can occur separately or together. Severity of symptoms in reaction to physical motion or visual motion stimuli varies widely and can change within an individual due to aging, adaptation, and comorbid disorders. We discuss the main methods for measuring motion sickness symptoms, the situations conducive to motion sickness and VIMS, and the individual traits associated with increased susceptibility. These additional considerations will improve diagnosis by fostering accurate measurement and understanding of the situational and personal factors associated with MSD and VIMSD

    Light painting photography makes particulate matter air pollution visible

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    The World Health Organization estimates that air pollution causes approximately seven million premature deaths worldwide each year. Solutions to air pollution are well known, yet this rarely equates to easily actionable. Here we demonstrate how art science collaboration can successfully highlight the issue of air pollution and create wider civic discourse around its amelioration. We document a light painting photographic technique that uses data from calibrated low-cost particulate matter sensors to measure and depict air pollution. We also use a postcard technique to grasp individuals’ sentiments regarding air pollution. The photographs from three countries, Ethiopia, India and United Kingdom, visually highlight the importance of location and occupation upon human exposure. The photographs are used as a proxy to communicate and create dialogues, spaces and places about air pollution. The sentiment analysis show how this approach can foster awareness and create agency for stakeholders to take actions to tackle air pollution

    Emergence of a Novel Avian Pox Disease in British Tit Species

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    Avian pox is a viral disease with a wide host range. In Great Britain, avian pox in birds of the Paridae family was first diagnosed in a great tit (Parus major) from south-east England in 2006. An increasing number of avian pox incidents in Paridae have been reported each year since, indicative of an emergent infection. Here, we utilise a database of opportunistic reports of garden bird mortality and morbidity to analyse spatial and temporal patterns of suspected avian pox throughout Great Britain, 2006–2010. Reports of affected Paridae (211 incidents) outnumbered reports in non-Paridae (91 incidents). The majority (90%) of Paridae incidents involved great tits. Paridae pox incidents were more likely to involve multiple individuals (77.3%) than were incidents in non-Paridae hosts (31.9%). Unlike the small wart-like lesions usually seen in non-Paridae with avian pox in Great Britain, lesions in Paridae were frequently large, often with an ulcerated surface and caseous core. Spatial analyses revealed strong clustering of suspected avian pox incidents involving Paridae hosts, but only weak, inconsistent clustering of incidents involving non-Paridae hosts. There was no spatial association between Paridae and non-Paridae incidents. We documented significant spatial spread of Paridae pox from an origin in south-east England; no spatial spread was evident for non-Paridae pox. For both host clades, there was an annual peak of reports in August/September. Sequencing of the avian poxvirus 4b core protein produced an identical viral sequence from each of 20 great tits tested from Great Britain. This sequence was identical to that from great tits from central Europe and Scandinavia. In contrast, sequence variation was evident amongst virus tested from 17 non-Paridae hosts of 5 species. Our findings show Paridae pox to be an emerging infectious disease in wild birds in Great Britain, apparently originating from viral incursion from central Europe or Scandinavia

    Combination antiretroviral therapy and the risk of myocardial infarction

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