THE INFLUENCE OF PARTICLE CONCENTRATION ON THE FLUID PHASE OF AN AXISYMMETRIC MULTIPHASE IMPINGING JET

Particle image velocimetry (PIV) is used to determine the effect of particle concentration on the fluid phase of a solid-liquid multiphase impinging jet. Two spherical particles were considered, polystyrene of 1050 kg m-3 and glass of 2450 kg m-3, both with a diameter of 225 μm. The fluid axial and radial velocities are measured with particle volume fractions (φ) equal to 0, 1x10-4, 2x10-4 and 4x10-4.For both particle types as the concentration is increased, the level of axial velocity retained immediately prior to impingement (at 6 diameters from the pipe exit) also increases. At low particle concentrations the particles have little effect on the flow turbulence, however, at higher particle concentrations the particle effect becomes more significant, with a near doubling of the peak axial RMS velocity one diameter from the jet outlet in one case. The introduction of polystyrene particles has the effect of dampening radial and axial RMS velocities, except for at the highest concentration immediately after the jet outlet where the axial turbulence is enhanced by the particles

Whither Capitalism? Financial externalities and crisis

As with global warming, so with financial crises – externalities have a lot to answer for. We look at three of them. First the financial accelerator due to ‘fire sales’ of collateral assets -- a form of pecuniary externality that leads to liquidity being undervalued. Second the ‘risk- shifting’ behaviour of highly-levered financial institutions who keep the upside of risky investment while passing the downside to others thanks to limited liability. Finally, the network externality where the structure of the financial industry helps propagate shocks around the system unless this is checked by some form of circuit breaker, or ‘ring-fence’. The contrast between crisis-induced Great Recession and its aftermath of slow growth in the West and the rapid - and (so far) sustained - growth in the East suggests that successful economic progress may depend on how well these externalities are managed

Activation of Ventral Tegmental Area 5-HT2C Receptors Reduces Incentive Motivation

FUNDING AND DISCLOSURE The research was funded by Wellcome Trust (WT098012) to LKH; and National Institute of Health (DK056731) and the Marilyn H. Vincent Foundation to MGM. The University of Michigan Transgenic Core facility is partially supported by the NIH-funded University of Michigan Center for Gastrointestinal Research (DK034933). The remaining authors declare no conflict of interest. ACKNOWLEDGMENTS We thank Dr Celine Cansell, Ms Raffaella Chianese and the staff of the Medical Research Facility for technical assistance. We thank Dr Vladimir Orduña for the scientific advice and technical assistance.Peer reviewedPublisher PD

Takeovers and cooperatives: governance and stability in non-corporate firms

Author's draft dated 11 January 2010. Final version published in Journal of economics available online at http://www.springerlink.com/If consumers wholly or partially control a firm with market power they will charge less than the profit maximizing price. Starting at the usual monopoly price, a small price reduction will have a second order effect on profits but a first order effect on consumer surplus. Despite this desirable static result, it has been argued that cooperatives are vulnerable to take-over by outsiders who will run them as for-profit businesses. This paper studies takeovers of cooperatives. We argue that there will not be excessive takeovers of cooperatives due to the Grossman-Hart problem of free riding during takeovers.Research in part supported by ESRC grant RES-000-22-0650

Evaluation of the impact of a school gardening intervention on children's fruit and vegetable intake: a randomised controlled trial.

Background: Current academic literature suggests that school gardening programmes can provide an interactive environment with the potential to change children’s fruit and vegetable intake. This is the first cluster randomised controlled trial (RCT) designed to evaluate whether a school gardening programme can have an effect on children’s fruit and vegetable intake. Methods: The trial included children from 23 schools; these schools were randomised into two groups, one to receive the Royal Horticultural Society (RHS)-led intervention and the other to receive the less involved Teacher-led intervention. A 24-hour food diary (CADET) was used to collect baseline and follow-up dietary intake 18 months apart. Questionnaires were also administered to evaluate the intervention implementation. Results: A total of 641 children completed the trial with a mean age of 8.1 years (95% CI: 8.0, 8.4). The unadjusted results from multilevel regression analysis revealed that for combined daily fruit and vegetable intake the Teacher-led group had a higher daily mean change of 8 g (95% CI: −19, 36) compared to the RHS-led group -32 g (95% CI: −60, −3). However, after adjusting for possible confounders this difference was not significant (intervention effect: −40 g, 95% CI: −88, 1; p = 0.06). The adjusted analysis of process measures identified that if schools improved their gardening score by 3 levels (a measure of school gardening involvement - the scale has 6 levels from 0 ‘no garden’ to 5 ‘community involvement’), irrespective of group allocation, children had, on average, a daily increase of 81 g of fruit and vegetable intake (95% CI: 0, 163; p = 0.05) compared to schools that had no change in gardening score. Conclusions: This study is the first cluster randomised controlled trial designed to evaluate a school gardening intervention. The results have found very little evidence to support the claims that school gardening alone can improve children’s daily fruit and vegetable intake. However, when a gardening intervention is implemented at a high level within the school it may improve children’s daily fruit and vegetable intake by a portion. Improving children’s fruit and vegetable intake remains a challenging task

A bi-directional relationship between obesity and health-related quality of life : evidence from the longitudinal AusDiab study

Objective: To assess the prospective relationship between obesity and health-related quality of life, including a novel assessment of the impact of health-related quality of life on weight gain.Design and setting: Longitudinal, national, population-based Australian Diabetes, Obesity and Lifestyle (AusDiab) study, with surveys conducted in 1999/2000 and 2004/2005.Participants: A total of 5985 men and women aged 25 years at study entry.Main outcome measure(s): At both time points, height, weight and waist circumference were measured and self-report data on health-related quality of life from the SF-36 questionnaire were obtained. Cross-sectional and bi-directional, prospective associations between obesity categories and health-related quality of life were assessed.Results: Higher body mass index (BMI) at baseline was associated with deterioration in health-related quality of life over 5 years for seven of the eight health-related quality of life domains in women (all P0.01, with the exception of mental health, P&gt;0.05), and six out of eight in men (all P&lt;0.05, with the exception of role-emotional, P=0.055, and mental health, P&gt;0.05). Each of the quality-of-life domains related to mental health as well as the mental component summary were inversely associated with BMI change (all P&lt;0.0001 for women and P0.01 for men), with the exception of vitality, which was significant in women only (P=0.008). For the physical domains, change in BMI was inversely associated with baseline general health in women only (P=0.023).Conclusions: Obesity was associated with a deterioration in health-related quality of life (including both physical and mental health domains) in this cohort of Australian adults followed over 5 years. Health-related quality of life was also a predictor of weight gain over 5 years, indicating a bi-directional association between obesity and health-related quality of life. The identification of those with poor health-related quality of life may be important in assessing the risk of future weight gain, and a focus on health-related quality of life may be beneficial in weight management strategies.<br /

Effectiveness of calf muscle stretching for the short-term treatment of plantar heel pain: a randomised trial

BACKGROUND: Plantar heel pain is one of the most common musculoskeletal disorders of the foot and ankle. Treatment of the condition is usually conservative, however the effectiveness of many treatments frequently used in clinical practice, including stretching, has not been established. We performed a participant-blinded randomised trial to assess the effectiveness of calf muscle stretching, a commonly used short-term treatment for plantar heel pain. METHODS: Ninety-two participants with plantar heel pain were recruited from the general public between April and June 2005. Participants were randomly allocated to an intervention group that were prescribed calf muscle stretches and sham ultrasound (n = 46) or a control group who received sham ultrasound alone (n = 46). The intervention period was two weeks. No participants were lost to follow-up. Primary outcome measures were 'first-step' pain (measured on a 100 mm Visual Analogue Scale) and the Foot Health Status Questionnaire domains of foot pain, foot function and general foot health. RESULTS: Both treatment groups improved over the two week period of follow-up but there were no statistically significant differences in improvement between groups for any of the measured outcomes. For example, the mean improvement for 'first-step' pain (0–100 mm) was -19.8 mm in the stretching group and -13.2 mm in the control group (adjusted mean difference between groups -7.9 mm; 95% CI -18.3 to 2.6). For foot function (0–100 scale), the stretching group improved 16.2 points and the control group improved 8.3 points (adjusted mean difference between groups 7.3; 95% CI -0.1 to 14.8). Ten participants in the stretching group experienced an adverse event, however most events were mild to moderate and short-lived. CONCLUSION: When used for the short-term treatment of plantar heel pain, a two-week stretching program provides no statistically significant benefit in 'first-step' pain, foot pain, foot function or general foot health compared to not stretching

Training with anxiety: short- and long-term effects on police officers’ shooting behavior under pressure

We investigated short- and long-term effects of training with anxiety on police officers’ shooting behavior under pressure. Using a pretest, posttest, and retention test design, 27 police officers executed a shooting exercise against an opponent that did (high anxiety) or did not (low anxiety) shoot back using colored soap cartridges. During the training sessions, the experimental group practiced with anxiety and the control group practiced without anxiety. At the pretest, anxiety had a negative effect on shot accuracy for both groups. At the posttest, shot accuracy of the experimental group no longer deteriorated under anxiety, while shot accuracy of the control group was still equally affected. At the retention test, 4 months after training, positive results for the experimental group remained present, indicating that training with anxiety may have positive short- and long-term effects on police officers’ shot accuracy under pressure. Additional analyses showed that these effects are potentially related to changes in visual attention on task-relevant information