The impact of cycle proficiency training on cycle-related behaviours and accidents in adolescence: findings from ALSPAC, a UK longitudinal cohort

ABSTRACT ObjectivesIn the UK, some children undertake National Cycle Proficiency Scheme [NCPS]/Bikeability training in primary school. It aims to promote cycling and safe cycling behaviours but there has been little scientific evaluation of its effectiveness. We aimed to examine the impact of cycle training on cycle-related behaviours and accidents in adolescence using self-report and hospital episode statistics (HES) data. ApproachThe sample (n=5415) were participants in the Avon Longitudinal Study of Parents and Children who reported whether or not they had received NCPS training. Self-reported outcomes at 14 and 16 years included: cycling to school, ownership of cycle helmet, use of cycle helmet and high-visibility clothing on last cycle, and involvement in a cycle accident. Hospital admittance due to a cycle accident from 11-16 years was also included for a subsample (n=2222) who have been linked to HES. The association between cycle training and each of the outcomes was analysed using multilevel logistic regression (individual level 1, school level 2 [pseudo-ID of school attended obtained from linkage to National Pupil Database]), adjusted for a range of potential confounders. ResultsApproximately 40% had received NCPS training. At 14 and 16 years, trained children were more likely to cycle to school (at 16 years: adjusted OR 1.56, 95% CI 1.20-2.02) and to own a helmet (16 years: 2.03, 1.72-2.41) than those who had not attended a course. They were also more likely to have worn a helmet on their last cycle at age 14 (1.26, 1.07-1.49), and to have worn high-visibility clothing at age 16 (1.70, 1.22-2.39). Training was not associated with self-reported involvement in a cycle accident, and only six participants with HES data had been admitted to hospital due to a cycle accident. Irrespective of training, results indicate very low use of high-visibility clothing (5%), very few girls cycling to school (<2%), and less than half of helmet owners wearing one on their last cycle. Ownership and use of helmets was particularly low in children from lower socio-economic position families. ConclusionCycle training for children can have benefits that persist into adolescence. However, the low use of cycle helmets and high-visibility clothing indicate the further potential for interventions to encourage safe cycling behaviours in young people. Our hospital admissions outcome only captures individuals who sustained serious injuries; more minor cycle injuries would have been treated in A&E but a lack of detail in admission codes precludes analysis of such data.

Analysis on Characteristics of Minor Cycle Errors in Process of Grinding Involute Gears on Worm Wheel Gear Grinding Machine

Usually, there are serious tooth-period errors in the process of grinding Involute gears on a worm wheel gear grinding machine. Being based on the process characteristics of grinding involute gears using a worm grinding wheel, radial errors and tangential errors of worm wheel gear grinding machine are analyzed. And conclusions for profile errors to be effected are given.

Design and Analysis on the Function of Huge Underground Space in Modern City

Since the begin of the 21st century, with the city construction scale expanding constantly, huge underground space has been an important trend of urban development, and will become one of the building types with modern cities symbol. On the other hand, the planning and designing of urban underground space function rationally are important ways to promote the urban functions. Combined with the project of Zhujiang Newtown CBD Underground Space in Guangzhou, the functional factors of huge underground space in modern city, and the design concept for modern urban huge underground space are discussed in this paper. At last, the function designs of Zhujiang Newtown CBD Underground Space are analyzed such as the innovation concept of underground traffic "minor cycle",the separation of pedestrians and vehicles, the sharing of space resource.

Stability of circadian and minor cycles of exocrine pancreatic secretion in atropine- and MK-329-infused rats

We previously demonstrated the existence of a circadian rhythm of pancreatic secretion of fluid and digestive enzymes, which was superimposed on by a regular 1.84-h minor cycle of exocrine pancreatic secretion of fluid and total protein, amylase, and chymotrypsinogen (25). Direct control of these daily and hourly rhythms of pancreatic secretory function has not been addressed. Cholinergic and cholecystokinin (CCK)-associated influences on these two rhythms of exocrine pancreatic secretion were investigated in rats provided with pancreatic, biliary, duodenal, and jugular vein cannulas, allowing separate drainage of bile and pure pancreatic juice, as well as intravenous infusions of atropine sulfate and/or MK-329. Rats were kept in restraint cages under controlled temperature and humidity, with a regular 12-h light cycle, and divided into five groups. The first group of fed rats was constantly infused with 200 micrograms.kg-1.h-1 atropine, the second with 0.5 mg.kg-1.h-1 MK-329, and the third with both. In the group where both drugs were simultaneously infused, 500 micrograms.kg-1.h-1 atropine was intraperitoneally administered, whereas MK-329 was infused by intravenous cannula. Two groups consisted of fasted rats, of which one was also given atropine (100 micrograms.kg-1.h-1). Three-day experiments were performed separately with fed rats, and 2-day experiments were performed with fasted rats; atropine and/or MK-329 infusion, starting on day 2, was constant over 48 h in both fed and fasted rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian rhythm of exocrine pancreatic secretion in rats: major and minor cycles

The circadian variations of exocrine pancreatic secretion were studied in conscious rats provided with pancreatic, biliary, duodenal, and peritoneal cannulas and kept in restraint cages under controlled conditions, with a regular 12-h light cycle. Rats were divided into fed and fasted groups, and experiments were performed separately. During a 4-day post-surgical recovery period, rats were fed ad libitum. During the experiment, fed rats had free access to food and water. Food, but not water, was denied fasted rats 10 h before the experiment and for its 48-h duration. During the experiment, pancreatic juice was continuously collected for 4 and 2 days from fed and fasted rats, respectively. Every 30 min, a 20-microliters aliquot of sampled pancreatic juice was removed for total protein, amylase, and chymotrypsinogen assays. The remainder was mixed with bile collected simultaneously, and the mixture was recirculated into the duodenum. Over the 4- and 2-day periods there was a clear circadian rhythm of 24-h duration; for all measured parameters, secretory rates increased in the dark period and decreased during the light period. This major circadian rhythm was unexpectedly found to be superimposed on by a remarkably constant neurosecretory-like minor cycle of 2-h duration present in both fed and fasted states. The amplitude of the minor cycle was diminished by fasting. The outputs of fluid, total protein, and amylase were found to be only modestly correlated with each other, whereas chymotrypsinogen output was virtually completely independent of the others. The results suggest that the spontaneous major increase of exocrine pancreatic secretion in the dark was at least partially independent of food intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Tentative world-wide correlation of Early Cretaceous strata by limestone-marl cyclicities in pelagic deposits

Bed-scale pelagic marl-limestone alternations at a number of localities in the Tethyan realm are cyclic and display common characters related to duration, composition, mineralogical and microfaunal content. Parameters used to characterize the cycles show parallel evolutions in time over large areas and thus allow accurate correlation. Cycle thickness variations, figured by "cyclograms", makes it possible to correlate sequences from southeastem France to the northeastem Gulf of Mexico and also to apply the biozonation of Angles' parastratotype, located in the Vocontian Trough, to the oceanic Valanginian sections. Variation curves of minor cycle frequency also expresse the accumulation rate which is mainly influenced by the production of planktonic carbonate. They allow North Atlantic and worldwide correlations, particularly for Hauterivian and Albian sections. Whatever the global cause was controlling the variation of planktonic productivity (either very long-term climatic fluctuations or eustatic changes), the curves, which reflect these variations, present an efficient stratigraphic tool for transoceanic correlations especially when biostratigraphic methods are ineffective. Furthermore, they reflect some major Lower Cretaceous boun­daries of the western Tethys.