6,678 research outputs found

    Maximum Normalized Rate as a Flying Qualities Parameter

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    Discrete attitude commands have become a standard task for flying qualities evaluation and control system testing. Much pilot opinion data is now available for ground-based and in-flight simulations, but adequate performance measures and prediction methods have not been established. The Step Target Tracking Prediction method, introduced in 1978, correlated time-on-target and rms tracking data with NT-33 in-flight longitudinal simulations, but did not employ parameters easily measured in manned flight and simulation. Recent application of the Step Target Tracking Prediction method to lateral flying qualities analysis has led to a new measure of performance. This quantity, called Maximum Normalized Rate (MNR), reflects the greatest attitude rate a pilot can employ during a discrete maneuver without excessive overshoot and oscillation. MNR correlates NT-33 lateral pilot opinion ratings well, and is easily measured during flight test or simulation. Futhermore, the Step Target MNR method can be used to analyze large amplitude problems concerning rate limiting and nonlinear aerodynamics

    Gender, Part-time Employment and Employee Participation in the Workplace: Comparing Australia and the European Union

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    The international trend in the growth and incidence of 'no n-standard employment', and its highly gendered nature, is well documented. For ease of definition, and because of the nature of the available data, we focus upon part-time employment in this paper. Employee participation may be defined as any workplace process which 'allows employees to exert some influence over their work and the conditions under which they work' (Strauss 1998). It may be divided into two main approaches, direct participation and indirect or representative participation. Direct participation involves the employee in job or task-oriented decision-making in the production process at the shop or office floor level. Indirect or representative forms of participation include joint consultative committees, works councils, and employee members of boards of directors or management. In the EU context statutory works councils are the most common expression of representative participation, but in Australia, consultative committees resulting from union/employer agreement or unilateral management initiative are the more common form. All of these forms of employee participation raise important issues concerning part time employees. Effective participation has two further major requirements which also may disadvantage part timers. First, there is a ge neral consensus in the participation literature that training is required for effective direct or representative participation. Secondly, effective communication between management and employees is required for participation, preferably involving a two-way information flow. The issue is of further significance since it has decided gender implications. This paper seeks to redress this relative insularity in the literature by examining some broad trends in this area in Australia and the EU. It analyses survey data at a national level in Australia and compares with some survey data generated in the EU by the EPOC project and analysed by Juliet Webster along the lines which we suggest here. It tests the hypothesis that the growth of one non-standard form of employment, part-time employment, diminishes the access to participation in the workplace enjoyed by female workers in comparison with their male colleagues, and finds that the hypothesis is strongly confirmed. This has major implications for workplace equity, and for organisational efficiency.gender, part-time employment, employee participation, Australia, European Union

    Association of Superoxide Dismutase 2 (SOD2) Genotype with Gray Matter Volume Shrinkage in Chronic Alcohol Users: Replication and Further Evaluation of an Addiction Gene Panel.

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    BackgroundReduction in brain volume, especially gray matter volume, has been shown to be one of the many deleterious effects of prolonged alcohol consumption. High variance in the degree of gray matter tissue shrinkage among alcohol-dependent individuals and a previous neuroimaging genetics report suggest the involvement of environmental and/or genetic factors, such as superoxide dismutase 2 (SOD2). Identification of such underlying factors will help in the clinical management of alcohol dependence.MethodsWe analyzed quantitative magnetic resonance imaging and genotype data from 103 alcohol users, including both light drinkers and treatment-seeking alcohol-dependent individuals. Genotyping was performed using a custom gene array that included genes selected from 8 pathways relevant to chronic alcohol-related brain volume loss.ResultsWe replicated a significant association of a functional SOD2 single nucleotide polymorphism with normalized gray matter volume, which had been reported previously in an independent smaller sample of alcohol-dependent individuals. The SOD2-related genetic protection was observed only at the cohort's lower drinking range. Additional associations between normalized gray matter volume and other candidate genes such as alcohol dehydrogenase gene cluster (ADH), GCLC, NOS3, and SYT1 were observed across the entire sample but did not survive corrections for multiple comparisons.ConclusionConverging independent evidence for a SOD2 gene association with gray matter volume shrinkage in chronic alcohol users suggests that SOD2 genetic variants predict differential brain volume loss mediated by free radicals. This study also provides the first catalog of genetic variations relevant to gray matter loss in chronic alcohol users. The identified gene-brain structure relationships are functionally pertinent and merit replication

    Mortality Model for a Perennial Grass in Australian Semi-Arid Wooded Grasslands Grazed by Sheep

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    Grazing of sheep in marginal semi-arid environments is risky because grazing appears to predispose grass plants, especially palatable species, to sudden death (Hodgkinson, 1994; 1995). These early observations were based on a preliminary analysis of perennial grass survival in a single drought and supported the concept of tactical grazing proposed by Westoby et al. (1989) as a preferred management. Later this idea was developed by suggesting the existence of critical thresholds for perennial grass survival, which when crossed, collapses grass populations (Hodgkinson, 1994). Here we examine the relationship between mortality of a palatable perennial grass, Thyridolepis mitchelliana, and a number of variables measured during a 10-year period

    An optical fiber hydrogen sensor using a palladium-coated ball lens

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    A self-referenced optical fiber refractometer using a ball lens as a sensor head has been developed and characterized. A 350-μm ball lens created at the tip of a single mode fiber has been coated with a 40-nm optically thin layer of palladium that reacts with hydrogen to form a hydride, which has a lower reflectivity than pure palladium. Optical reflectance measurements from the tip of the ball lens were performed to determine the hydrogen response. The change in reflectivity is proportional to the hydrogen concentration in the range 0% to 1% hydrogen in air with a detection limit down to 10 ppm (1σ) in air. This technique offers a simple sensor head arrangement, with a larger sampling area (~40 times) than a typical single-mode fiber core. A statistical image analysis of a palladium film, with cracks created by accelerated failure, confirms that the anticipated sensor area for a ball lens sensor head has a more predictable reflectivity than that of a bare fiber core

    Exploring Methods in Managerial and Organizational Cognition:Advances, Controversies, and Contributions

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    This book comprises the second volume in the recently launched New Horizons in Managerial and Organizational Cognition book series. Volume 1 (Sund, Galavan, & Huff, 2016), addressed the topic of strategic uncertainty. This second volume comprises a collection of contributions that variously report new methodological developments in managerial and organizational cognition, reflect critically on those developments, and consider the challenges that have yet to be confronted in order to further advance this exciting and dynamic interdisciplinary field. Contextualizing within an overarching framework the various contributions selected for inclusion in the present volume, in this opening chapter we reflect more broadly on what we consider the most significant developments that have occurred over recent years and the most significant challenges that lie ahead
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