Some hypersonic intake studies

A 'two dimensional' air intake comprisipg a wedge followed by an isentropic compression has been tested in the Cranfield Gun Tunnel at Mach 8,2. These tests were performed to investigate qualitatively the intake flow starting process. The effects of cowl position, Reynolds number, boundary-layer trip and introduction of a small restriction in the intake duct were investigated. Schlieren pictures of the flow on the compression surface and around the intake entrance were taken. Results showed that the intake would operate over the Reynolds number range tested. Tests with a laminar boundary layer demonstrated the principal influence of the Reynolds number on the boundary-layer growth and consequently on the flow structure in the intake entrance. In contrast boundary layer tripping produced little variation in flow pattern over the Reynolds number range tested. The cowl lip position appeared to have a strong effect on the intake performance. The only parameter which prevented the intake from starting was the introduction of a restriction in the intake duct. The experimental data obtained were in good qualitative agreement with the CFD predictions. Finally, these experimental results indicated a good intake flow starting process over multiple changes of parameters

Monopsony Processing in an Open-Access Fishery

In a recent paper, Clark and Munro (1980) showed that monopsony processing more than offsets the effects of open-access in the harvesting sector of a commercial fishery, and leads to overconservation of the resource. We show here that this conclusion depends critically on the cost of capacity and consequent ease of entry and exit from the harvesting sector. In particular, for low entry and exit speeds the monopsonist has a high degree of monopoly power and by depressing the price overconserves the natural resource relative to the social optimum, while as the adjustment speed approaches infinity a monopsonist employing a discount rate equal to the social rate of discount will be induced to behave optimally from the viewpoint of society. By means of a simulation employing parameters from the Pacific halibut fishery, we also show that a monopsonist subject to relatively sluggish entry or exit may reap profits considerably less than the resource rents accruing if the resource were optimally managed.Environmental Economics and Policy, Production Economics, Resource /Energy Economics and Policy,

Regulation of Stochastic Fisheries: A Comparison of Alternative Methods in the Pacific Halibut Fishery

This article considers the relative merits of ad valorem taxation, season controls, and entry limitation as methods the government may use to deal with the externality problem in the Pacific halibut fishery. This is accomplished by simulating a stochastic dynamic program that uses parameters obtained from empirical analysis of this fishery. Although we find taxation to be the preferred regulatory instrument, the efficiency gains from regulation are minor when compared with the losses associated with the demand, output, and stock uncertainty in the fishery.Environmental Economics and Policy, Resource /Energy Economics and Policy, Risk and Uncertainty,

Job satisfaction in young professional athletic trainers

Job satisfaction levels in young professional athletic trainers in multiple settings were examined quantitatively using the Job Satisfaction Survey (Spector, 1997) and qualitatively using an open-ended survey question. Job satisfaction levels were calculated to find that young professional athletic trainers are satisfied with their jobs according to the normative mean data for the scale. Post hoc analysis of the comparison of satisfaction levels by setting suggests that college/university athletic trainers have significantly lower job satisfaction levels than secondary school and clinic/outreach athletic trainers. Qualitative data suggests a high negative response rate revealing pay and operating procedures as two of the most important facets of job satisfaction. These findings suggest that a qualitative assessment of job satisfaction will provide better data for analysis regarding the job satisfaction of young professional athletic trainers

A Stochastic Dynamic Programming Model of Bycatch Control in Fisheries

This paper builds a model of fishery regulation with incidental catch or bycatch and simulates it with parameters from the Nova Scotia cod and haddock fisheries. When comparing optimal coordinated taxation with the independent taxation of each fishery separately, we find that independent taxation requires significantly higher tax rates to control the stock externality associated with competitive behaviour. Quotas are found to be suboptimal relative to any form of taxation, because of their inflexibility in the presence of uncertainty, and because they can control bycatch only indirectly.Production Economics,

Plume effects on the flow around a blunted cone at hypersonic speeds

Tests at M = 8.2 show that a simulated rocket plume at the base of a blunted cone can cause large areas of separated flow, with dramatic effects on the heat transfer rate distribution. The plume was simulated by solid discs of varying sizes or by an annular jet of gas. Flow over the cone without a plume is fully laminar and attached. Using a large disc, the boundary layer is laminar at separation at the test Reynolds number. Transition occurs along the separated shear layer and the boundary layer quickly becomes turbulent. The reduction in heat transfer associated with a laminar separated region is followed by rising values as transition occurs and the heat transfer rates towards the rear of the cone substantially exceed the values obtained without a plume. With the annular jet or a small disc, separation occurs much further aft, so that heat transfer rates at the front of the cone are comparable with those found without a plume. Downstream of separation the shear layer now remains laminar and the heat transfer rates to the surface are significantly lower than the attached flow values

Artifice and the science of sweet

Thesis (S.M. in Science Writing)--Massachusetts Institute of Technology, Dept. of Humanities, Graduate Program in Science Writing, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 37-40).Aspartame has become an extremely popular artificial sweetener since its entry into the American market in 1981. Humans have an evolutionary preference for sweet tastes, and artificial sweeteners became a mainstream alternative to cane sugar in the 2 0 th century for people looking to cut calories. Saccharin and cyclamates, both discovered accidentally in early chemistry labs, set the scientific precedent for low-calorie sweeteners and also built the consumer base that would lead to aspartame's rise after its own accidental discovery in 1965. This thesis takes a journalistic look at how artifice came to satisfy the human sweet tooth. Drawing on expert interviews, scientific papers, historical accounts and congressional records, it also examines some of the health complaints like headaches and seizures that have been attributed to aspartame's breakdown products, such as phenylalanine. Even after extensive FDA testing has found little scientific proof for many of these claims, controversy and uncertainty about aspartame persist. There are also new challenges: researchers are now investigating the idea that consuming diet drinks may actually contribute to weight gain. At the same time, as obesity rates climb and schools and cities look to ban calorie-dense sodas, many public health experts welcome aspartame because it poses a less clear-cut risk than sugar.by Allison MacLachlan.S.M.in Science Writin

Alternative empires : Soviet montage cinema, the British documentary movement & colonialism

This is a study of Soviet montage cinema and the British documentary movement of the 1930s which brings together two usually divergent methodologies: postcolonial theory and "new" film history. The first chapter develops new insights into Eisenstein's October and Vertov's The Man With the Movie Camera, The second analyses two less well-known Vertov films, One Sixth of the Earth and Three Songs of Lenin, from the perspective of postcolonial theory, The third considers Pudovkin's Storm Over Asia and traces its reception in both the Soviet Union and England. The fourth and fifth chapters expand general issues and themes raised by the first two, and pursue specific questions raised by the third. These final chapters resituate the work of the British documentary movement in relation to the culture of British imperialism. This shift of focus entails the analysis of the production and contemporary critical reception of a number of films which have been marginalised in most retrospective historical accounts of the movement. By recontextualising these two groups of films, this study attempts to demonstrate how their various representations of the non-Western world are intertwined with and necessarily involve considering other issues, such as: periodisation within film history; the "influence" of Soviet montage on the British documentary movement; the construction of authorship; the division between "high" and "low" culture; the relationship between politics and film aesthetics; the postcolonial challenge to Marxism; cinematic internationalism. The first two chapters also integrate an ongoing critique of certain trends within post-1968 film theory and criticism, which developed in close association with a retrieval and revaluation of Soviet montage cinema and Soviet avant-garde culture of the 1920s, One of the aims of this thesis is to question some of the assumptions of this work, whilst at the same time demonstrating that historical research, even as it attempts to reconstruct former contexts, need not consign its objects of study to the past, but can be used instead to raise questions relevant to the present. In this respect, the thesis tries to remain closer to the spirit of post-1968 than does much of the more recent, "new" historical research into Soviet cinema and the British documentary movement, to which it is nevertheless greatly indebted

Using Active Shape Modeling Based on MRI to Study Morphologic and Pitch-Related Functional Changes Affecting Vocal Structures and the Airway

Copyright © 2013 The Voice Foundation. Published by Mosby, Inc. All rights reserved.Peer reviewedPostprin

Glucose improves object-location binding in visual-spatial working memory

RATIONALE: There is evidence that glucose temporarily enhances cognition and that processes dependent on the hippocampus may be particularly sensitive. As the hippocampus plays a key role in binding processes, we examined the influence of glucose on memory for object-location bindings. OBJECTIVE: This study aims to study how glucose modifies performance on an object-location memory task, a task that draws heavily on hippocampal function. METHODS: Thirty-one participants received 30 g glucose or placebo in a single 1-h session. After seeing between 3 and 10 objects (words or shapes) at different locations in a 9 × 9 matrix, participants attempted to immediately reproduce the display on a blank 9 × 9 matrix. Blood glucose was measured before drink ingestion, mid-way through the session, and at the end of the session. RESULTS: Glucose significantly improves object-location binding (d = 1.08) and location memory (d = 0.83), but not object memory (d = 0.51). Increasing working memory load impairs object memory and object-location binding, and word-location binding is more successful than shape-location binding, but the glucose improvement is robust across all difficulty manipulations. Within the glucose group, higher levels of circulating glucose are correlated with better binding memory and remembering the locations of successfully recalled objects. CONCLUSIONS: The glucose improvements identified are consistent with a facilitative impact on hippocampal function. The findings are discussed in the context of the relationship between cognitive processes, hippocampal function, and the implications for glucose’s mode of action