71,645 research outputs found
Open loop digital frequency multiplier
An open loop digital frequency multiplier is described which has a multiplied output synchronized to low frequency clock pulse. The system includes a multistage digital counter which provides a pulse output as a function of an integer divisor. The integer divisor and the timing or counting cycle of the counter are interrelated to the frequency of a clock input. The counting cycle is controlled by a one shot multivibrator which, in turn, is driven by a reference frequency input
A Suggestion for Extension of the NASA RANGER Project in Support of Manned Space Flight
Proposal for utilizing Ranger project in support of Surveyor and Apollo project
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Free healthy breakfasts in primary schools: A cluster randomised controlled trial of a policy intervention in Wales, UK
Objective: The present study evaluated the impact of a national school programme of universal free healthy breakfast provision in Wales, UK.
Design: A cluster randomised controlled trial with repeated cross-sectional design and a 12-month follow-up. Primary outcomes were breakfast skipping, breakfast diet and episodic memory. Secondary outcomes were frequency of eating breakfast at home and at school, breakfast attitudes, rest-of-day diet and class behaviour.
Setting: Primary schools in nine local education authority areas.
Subjects: A total of 4350 students (aged 9–11 years) at baseline and 4472 at follow-up in 111 schools.
Results: Students in intervention schools reported significantly higher numbers of healthy food items consumed at breakfast and more positive attitudes towards breakfast eating at 12 months. Parents in intervention schools reported significantly higher rates of consumption of breakfast at school and correspondingly lower rates of breakfast consumption at home. No other significant differences were found.
Conclusions: The intervention did not reduce breakfast skipping; rather, pupils substituted breakfast at home for breakfast at school. However, there were improvements in children’s nutritional intake at breakfast time, if not the rest of the day, and more positive attitudes to breakfast, which may have implications for life-course dietary behaviours. There was no impact on episodic memory or classroom behaviour, which may require targeting breakfast skippers
Helium Leak Measurements Using CO2 as a Carrier
Detection delay defects are omitted by using helium mass spectrometer leak detector combined with several known procedures. Technique combines carbon dioxide purging, cryogenic separating helium accumulation, and use of carbon dioxide as carrier gas
Structure of the Alkali-metal-atom-Strontium molecular ions: towards photoassociation and formation of cold molecular ions
The potential energy curves, permanent and transition dipole moments, and the
static dipolar polarizability, of molecular ions composed of one alkali-metal
atom and a Strontium ion are determined with a quantum chemistry approach. The
molecular ions are treated as effective two-electron systems and are treated
using effective core potentials including core polarization, large gaussian
basis sets, and full configuration interaction. In the perspective of upcoming
experiments aiming at merging cold atom and cold ion traps, possible paths for
radiative charge exchange, photoassociation of a cold Lithium or Rubidium atom
and a Strontium ion are discussed, as well as the formation of stable molecular
ions
A study of earth radar returns from Alouette satellite
Ground radar reflection coefficient analysis on Alouette sounder ionogram
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