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Material for publication as a Communication must be on a n urgent matter and be of obvious scientific importance. Rapidity of publication i s enhanced if diagrams are omitted, but tables and formulae can be included. Communications should not be simple claims for priority: this facility for rapid publication i s intended for brief descriptions of work that has progressed to a stage at which it is likely to be valuable to workers faced with similar problems. A fuller paper may be ojjfered subsequently, if justi,fied by later work.Manuscripts are not subjected to the usual examination by referees and inclusion of a Communication is at the Editor's discretion.

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