Radial- and mixed-flow turbines for low head microhydro systems

This paper describes the design of two different specific speed microhydro turbines operating at heads between 6 and 12 m, at small scale and up to heads of 50 m at larger scales. The features are specifically tailored for ease of manufacture and uniquely resistant to debris blockage. Test machines are described and test results given; hydraulic efficiencies of over 70% have been achieved in all test models despite the fact that the turbine blades are made from flat plate, specifically to simplify manufacture. Outline drawings are given with key dimensions for each reference model, along with the equations for scaling to arbitrary sizes. These turbines are the mixed- and radial-flow members of a family of turbines developed to cover the microhydro range from 2 to about 50 m of head, which is below the range where Pelton wheels are applicable.     

Impact of speed change on estimated journey time: Failure of drivers to appreciate relevance of initial speed

Higher speeds are associated with increases in the probability of crashing and the severity of the outcome. Logically drivers speed to save time, and research evidence supports this assertion. It is therefore important to investigate drivers’ understanding of how speed change impacts on journey time. Since it is likely that drivers do not appreciate the reciprocal nature of the function which links these two variables, and its implications, two predictions can be made: the impact of a speed change will be underestimated at low speeds and overestimated at high speeds. This issue was addressed through four questions generated by manipulating Speed Change (increase versus decrease) and Starting Speed (30 mph versus 60 mph) with the participants being asked how they felt these variables would impact on journey time. These were included in a large survey addressing speed-related issues. Participants were a representative quota sample of 1005 UK drivers, interviewed by questionnaire. The findings indicated that three of the four questions produced results consistent with the predictions made. Furthermore, a repeated measures factorial ANOVA indicated that there was no real appreciation of how starting speed impacted on journey time. A disordinal interaction provided evidence that drivers wrongly believed that as starting speed increased the impact of a speed rise also increased; the opposite is true. For speed decreases, drivers appeared to think that starting speed had little impact on the amount of time saved. It is recommended that these findings be integrated into driver training and speed awareness courses.     

Fluoxetine increases norepinephrine release in rat hypothalamus as measured by tissue levels of MHPG-SO4 and microdialysis in conscious rats

The selective serotonin uptake inhibitor fluoxetine (10 mg/kg i.p.) increased tissue levels of the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethylene glycol sulfate (MHPG-SO4) in rat hypothalamus, indicating an increased release of norepinephrine. Microdialysis studies in conscious rats showed that fluoxetine (10 mg/kg i.p.) increased extracellular concentrations of norepinephrine as well as serotonin in the hypothalamus. In contrast, desipramine (10 mg/kg i.p.) increased extracellular concentration of norepinephrine but not serotonin in the hypothalamus. Consistent with its mechanism of being a selective serotonin uptake inhibitor, local perfusion of fluoxetine (10 microM) caused a 7-fold increase in hypothalamic extracellular serotonin and a small non-significant increase in extracellular norepinephrine. The subsequent systemic injection of fluoxetine (10 mg/kg s.c.) after local perfusion caused a 3-fold increase in extracellular norepinephrine, indicating that fluoxetine's action leading to an increase in extracellular norepinephrine was not occurring in the terminal areas of the hypothalamus but elsewhere in the brain, possibly cell bodies in the locus coeruleus.     

Menstrual cycle modulation of tender points

OBJECTIVE: A summary about the final results of the Hungarian double-blind placebo controlled randomised trial of periconceptional folic acid containing multivitamin and trace element supplementation. RESULTS: The major finding is a significant prevention of the first occurrence of neural-tube defect, urinary tract and cardiovascular defects, in addition a decrease in the rate of limb deficiencies and congenital hypertrophic pyloric stenosis. Fertility was slightly improved and the rate of twins increased significantly after periconceptional multivitamin supplementation. The effect of multivitamin supplementation for fetal death is controversial, but in general there is no clinically significant change. Periconceptional multivitamin supplementation can reduce the occurrence of nausea and vomiting. PRACTICAL IMPLEMENTATIONS: Consumption of foods which are rich in folate may not be the best way to prevent neural-tube defects and other congenital abnormalities. Periconceptional multivitamin supplementation is part of the periconceptional care in Hungary and it is an appropriate forum for the practical delivery for this primary prevention action. However, as a large proportion of pregnancies are unplanned, the widespread use of bread fortified with folic acid, vitamin B12 and B6 may decrease a considerable part of neural-tube defects and some other congenital abnormalities, in addition to vascular diseases due to hyperhomocysteinemia.