305 research outputs found
First principles numerical model of avalanche-induced arc discharges in electron-irradiated dielectrics
The model consists of four phases: single electron dynamics, single electron avalanche, negative streamer development, and tree formation. Numerical algorithms and computer code implementations are presented for the first three phases. An approach to developing a code description of fourth phase is discussed. Numerical results are presented for a crude material model of Teflon
Tactile Sensory Supplementation of Gravitational References to Optimize Sensorimotor Recovery
Integration of multi-sensory inputs to detect tilts relative to gravity is critical for sensorimotor control of upright orientation. Displaying body orientation using electrotactile feedback to the tongue has been developed by Bach-y- Rita and colleagues as a sensory aid to maintain upright stance with impaired vestibular feedback. This investigation has explored the effects of Tongue Elecrotactile Feedback (TEF) for control of posture and movement as a sensorimotor countermeasure, specifically addressing the optimal location of movement sensors
Which Way is Up? Lessons Learned from Space Shuttle Sensorimotor Research
The Space Shuttle Program provided the opportunity to examine sensorimotor adaptation to space flight in unprecedented numbers of astronauts, including many over multiple missions. Space motion sickness (SMS) severity was highly variable across crewmembers. SMS generally lasted 2-3 days in-flight with approximately 1/3 of crewmembers experiencing moderate to severe symptoms, and decreased incidence in repeat flyers. While SMS has proven difficult to predict from susceptibility to terrestrial analogs, symptoms were alleviated by medications, restriction of early activities, maintaining familiar orientation with respect to the visual environment and maintaining contact cues. Adaptive changes were also reflected by the oculomotor and perceptual disturbances experienced early inflight and by the perceptual and motor coordination problems experienced during re-entry and landing. According to crew self-reports, systematic head movements performed during reentry, as long as paced within one's threshold for motion tolerance, facilitated the early readaptation process. The Shuttle provided early postflight crew access to document the initial performance decrements and time course of recovery. These early postflight measurements were critical to inform the program of risks associated with extending the duration of Shuttle missions. Neurological postflight deficits were documented using a standardized subjective rating by flight surgeons. Computerized dynamic posturography was also implemented as a quantitative means of assessing sensorimotor function to support crew return-to-duty assessments. Towards the end of the Shuttle Program, more emphasis has been placed on mapping physiological changes to functional performance. Future commercial flights will benefit from pre-mission training including exposures to launch and entry G transitions and sensorimotor adaptability assessments. While SMS medication usage will continue to be refined, non-pharmacological countermeasures (e.g., sensory aids) will have both space and Earth-based applications. Early postflight field tests are recommended to provide the evidence base for best practices for future commercial flight programs. Learning Objective: Overview of the Space Shuttle Program regarding adaptive changes in sensorimotor function, including what was learned from research, what was implemented for medical operations, and what is recommended for commercial flights
Governance, regulation and financial market instability: the implications for policy
Just as the 1929 Stock Market Crash discredited Classical economic theory and policy and opened the way for Keynesianism, a consequence of the collapse of confidence in financial markets and the banking system—and the effect that this has had on the global macro economy—is currently discrediting the ‘conventional wisdom’ of neo-liberalism. This paper argues that at the heart of the crisis is a breakdown in governance that has its roots in the co-evolution of political and economic developments and of economic theory and policy since the 1929 Stock Market Crash and the Great Depression that followed. However, while many are looking back to the Great Depression and to the theories and policies that seemed to contribute to recovery during the first part of the twentieth century, we argue that the current context is different from the earlier one; and there are more recent events that may provide better insight into the causes and contributing factors giving rise to the present crisis and to the implications for theory and policy that follow
Violence today
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45468/1/11089_2005_Article_BF01768523.pd
How the Fed Reanimated Wall Street: The Low and Extended Lending Rates that Revived the Big Banks
Walter Bagehot's putative principles of lending in liquidity crises - to lend freely to solvent banks with good collateral but at penalty rates - have served as a theoretical basis for thinking about the lender of last resort for close to 100 years, while simultaneously providing justification for central bank real-world intervention. If we presume Bagehot's principles to be both sound and adhered to by central bankers, we would expect to find the lending by the Fed during the global financial crisis in line with such policies. Taking Bagehot's principles at face value, this paper aims to examine one of these principles - central bank lending at penalty rates - and to determine whether it did in fact conform to this standard. A comprehensive analysis of these rates has revealed that the Fed did not, in actuality, follow Bagehot's classical doctrine. Consequently, the intervention not only generated moral hazard but also set the stage for another crisis. This working paper is part of the Ford Foundation project A Research and Policy Dialogue Project on Improving Governance of the Government Safety Net in Financial Crisis and continues the investigation of the Fed's bailout of the financial system - the most comprehensive study of the raw data to date
BMQ
BMQ: Boston Medical Quarterly was published from 1950-1966 by the Boston University School of Medicine and the Massachusetts Memorial Hospitals
Functional Task Test: 1. Sensorimotor changes Associated with Postflight Alterations in Astronaut Functional Task Performance
Space flight is known to cause alterations in multiple physiological systems including changes in sensorimotor, cardiovascular, and neuromuscular systems. These changes may affect a crewmember s ability to perform critical mission tasks immediately after landing on a planetary surface. The overall goal of this project is to determine the effects of space flight on functional tests that are representative of high priority exploration mission tasks and to identify the key underlying physiological factors that contribute to decrements in performance. This presentation will focus on the sensorimotor contributions to postflight functional performance
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