Price Cycles and Price Leadership in Gasoline Markets: New Evidence from Canada

This paper studies the determinants of Edgeworth Cycles, price leadership and coordination in retail gasoline markets using daily station-level price data for 110 markets in Ontario, Canada for 2007-2008. We find an “inverse-U” relationship between markets’ propensity to exhibit price cycles and their size. More concentrated markets are less likely to exhibits cycles and we highlight regional clustering among cycling and non-cycling markets. Within cycling markets, we find brands’ stations (Esso, Shell,Petro-Canada, Sunoco) lead price jumps and coordinate market prices, while independents (Ultramar, Pioneer, Olco, MacEwen) aggressively undercut prices over the cycle.Retail gasoline prices; Edgeworth Cycles; Price leadership; Coordination

Subsonic Aerodynamic Characteristics of a Circular Body Earth-to-Orbit Vehicle

A test of a generic reusable earth-to-orbit transport was conducted in the 7- by 10-Foot high-speed tunnel at the Langley Research Center at Mach number 0.3. The model had a body with a circular cross section and a thick clipped delta wing as the major lifting surface. For directional control, three different vertical fin arrangements were investigated: a conventional aft-mounted center vertical fin, wingtip fins, and a nose-mounted vertical fin. The configuration was longitudinally stable about the estimated center-of-gravity position of 0.72 body length and had sufficient pitch-control authority for stable trim over a wide range of angle of attack, regardless of fin arrangement. The maximum trimmed lift/drag ratio for the aft center-fin configuration was less than 5, whereas the other configurations had values of above 6. The aft center-fin configuration was directionally stable for all angles of attack tested. The wingtip and nose fins were not intended to produce directional stability but to be active controllers for artificial stabilization. Small rolling-moment values resulted from yaw control of the nose fin. Large adverse rolling-moment increments resulted from tip-fin controller deflection above 13 deg angle of attack. Flow visualization indicated that the adverse rolling-moment increments were probably caused by the influence of the deflected tip-fin controller on wing flow separation

Exploring Differences in Pain Beliefs Within and Between a Large Nonclinical (Workplace) Population and a Clinical (Chronic Low Back Pain) Population Using the Pain Beliefs Questionnaire

BACKGROUND: Beliefs, cognitions, and behaviors relating to pain can be associated with a range of negative outcomes. In patients, certain beliefs are associated with increased levels of pain and related disability. There are few data, however, showing the extent to which beliefs of patients differ from those of the general population. OBJECTIVE: This study explored pain beliefs in a large nonclinical population and a chronic low back pain (CLBP) sample using the Pain Beliefs Questionnaire (PBQ) to identify differences in scores and factor structures between and within the samples. DESIGN: This was a cross-sectional study. METHODS: The samples comprised patients attending a rehabilitation program and respondents to a workplace survey. Pain beliefs were assessed using the PBQ, which incorporates 2 scales: organic and psychological. Exploratory factor analysis was used to explore variations in factor structure within and between samples. The relationship between the 2 scales also was examined. RESULTS: Patients reported higher organic scores and lower psychological scores than the nonclinical sample. Within the nonclinical sample, those who reported frequent pain scored higher on the organic scale than those who did not. Factor analysis showed variations in relation to the presence of pain. The relationship between scales was stronger in those not reporting frequent pain. LIMITATIONS: This was a cross-sectional study; therefore, no causal inferences can be made. CONCLUSIONS: Patients experiencing CLBP adopt a more biomedical perspective on pain than nonpatients. The presence of pain is also associated with increased biomedical thinking in a nonclinical sample. However, the impact is not only on the strength of beliefs, but also on the relationship between elements of belief and the underlying belief structur

Multi-centre parallel arm randomised controlled trial to assess the effectiveness and cost-effectiveness of a group-based cognitive behavioural approach to managing fatigue in people with multiple sclerosis

Abstract (provisional) Background Fatigue is one of the most commonly reported and debilitating symptoms of multiple sclerosis (MS); approximately two-thirds of people with MS consider it to be one of their three most troubling symptoms. It may limit or prevent participation in everyday activities, work, leisure, and social pursuits, reduce psychological well-being and is one of the key precipitants of early retirement. Energy effectiveness approaches have been shown to be effective in reducing MS-fatigue, increasing self-efficacy and improving quality of life. Cognitive behavioural approaches have been found to be effective for managing fatigue in other conditions, such as chronic fatigue syndrome, and more recently, in MS. The aim of this pragmatic trial is to evaluate the clinical and cost-effectiveness of a recently developed group-based fatigue management intervention (that blends cognitive behavioural and energy effectiveness approaches) compared with current local practice. Methods This is a multi-centre parallel arm block-randomised controlled trial (RCT) of a six session group-based fatigue management intervention, delivered by health professionals, compared with current local practice. 180 consenting adults with a confirmed diagnosis of MS and significant fatigue levels, recruited via secondary/primary care or newsletters/websites, will be randomised to receive the fatigue management intervention or current local practice. An economic evaluation will be undertaken alongside the trial. Primary outcomes are fatigue severity, self-efficacy and disease-specific quality of life. Secondary outcomes include fatigue impact, general quality of life, mood, activity patterns, and cost-effectiveness. Outcomes in those receiving the fatigue management intervention will be measured 1 week prior to, and 1, 4, and 12 months after the intervention (and at equivalent times in those receiving current local practice). A qualitative component will examine what aspects of the fatigue management intervention participants found helpful/unhelpful and barriers to change. Discussion This trial is the fourth stage of a research programme that has followed the Medical Research Council guidance for developing and evaluating complex interventions. What makes the intervention unique is that it blends cognitive behavioural and energy effectiveness approaches. A potential strength of the intervention is that it could be integrated into existing service delivery models as it has been designed to be delivered by staff already working with people with MS. Service users will be involved throughout this research. Trial registration: Current Controlled Trials ISRCTN7651747

Living In Cold Homes After Heating Improvements: Evidence From Warm Front, England's Home Energy Efficiency Scheme.

Objective: To investigate explanatory factors for persistent cold temperatures in homes which have received heating improvements. Design: Analysis of data from a national survey of dwellings and households (in England occupied by low-income residents) that had received heating improvements or repairs under the Warm Front Scheme. Methods: Over the winters of 2001–02 and 2002–03, householders recorded living room and main bedroom temperatures in a diary. Entries were examined for 888 households, which had received high level heating interventions. Two hundred and twenty-two households were identified as occupying cold homes, with mean bedroom temperature below 16 °C or mean living room temperatures below 18 °C. Binary logistic regression was used to model dwelling and household features and then occupants’ behaviour and attitudes in the ‘cold homes’ sub-set compared with the remainder of the high intervention group. Seventy-nine supplementary, structured telephone interviews explored reasons given for lower temperatures. Using graphical and tabular methods, householders preferring cooler homes were distinguished from those who felt constrained in some way. Results: Cold homes predominate in pre-1930 properties where the householder remains dissatisfied with the heating system despite major improvements funded by Warm Front. Residents of cold homes are less likely to have long-standing illness or disability, but more likely to experience anxiety or depression. A small sample of telephone interviews reveals those preferring lower temperatures for health or other reasons, report less anxiety and depression than those with limited control over their home environment. Their ‘thermal resistance’ to higher temperatures challenges orthodox definitions of comfort and fuel poverty