Limits to improvements?
Article Abstract:
Physicists had wanted to improve atomic clocks by using an arrangement called an atomic fountain where atoms cooled to microkelvin temperatures. Unfortunately, the frequency standard could be affected by the collision of chilled atoms. This possibility was proven by an experiment conducted by K. Gibble and S. Chu. Details of the experiment are presented. Gibble and Chu demonstrate that the frequency standard can shift by -4.8 megahertz for a density of 10(super 9) cm(super -3). This indicates that ultracold collisions have to be considered when using atomic fountains for frequency standards.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1993
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Fishing by numbers reveals its limits
Article Abstract:
The most significant issue in global fisheries nowadays is overfishing which includes catching fish before they could breed and lay eggs. The Common Fisheries Policy has tried to regulate fishing in European Union waters by designating quotas for each member state, however, fishermen often disobeyed the rule. An attempt to impose restrictions in fishing to certain areas has failed because fishermen could not understand the regulations which were too complicated.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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