منابع مشابه
Rooks on Ferrers Boards and Matrix Integrals
Let C(n; N) = R H N tr Z 2n (dZ) denote a matrix integral by a U(N)-invariant gaussian measure on the space H N of hermitian N N matrices. The integral is known to be always a positive integer. We derive a simple combinatorial interpretation of this integral in terms of rook conngurations on Ferrers boards. The formula C(n; N) = (2n ? 1)!! n X k=0 N k + 1 n k 2 k found by J. Harer and D. Zagier...
متن کاملWeed Control in Walnuts
Annual and perennial weed control trials were retreatedin Butte, Solano and Yolo counties. The diversified locations continue to provide a vital basis for applicable information on walnut tree tolerance to herbicides and on weed control efficacy. Herbicidal control of a wide spectrum of annual or perennial grass and broadleaf plants has been evaluated for the winter and summer periods of 1980. ...
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Research into practical control methods for carpenterworm, Prionoxystus robiniae (Peck), a large wood boring larva, was continued. Observations indicate this pest primarily attacks older trees of the Hartley variety that are infected with deep bark canker, a stress-related bacterial disorder. Carpenterworm (CW) also attacks the Franquette variety. Hartley orchards with substantial deep bark can...
متن کاملInvestigating Physical Cognition in Rooks, Corvus frugilegus
Although animals (particularly tool-users) are capable of solving physical tasks in the laboratory , the degree to which they understand them in terms of their underlying physical forces is a matter of contention. Here, using a new paradigm, the two-trap tube task, we report the performance of non-tool-using rooks. In contrast to the low success rates of previous studies using trap-tube problem...
متن کاملWalnuts and endothelial function in hypercholesterolemic subjects.
Hypercholesterolemic Subjects To the Editor: Ros et al1 recently reported that substituting walnuts for monounsaturated fat in a Mediterranean-type diet improves endothelial function in hypercholesterolemic subjects. The investigators explain that nuts contain sizable amounts of antioxidants, as well as L-arginine and -linolenic acid, which might also confer additional antiatherogenic propertie...
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ژورنال
عنوان ژورنال: Nature
سال: 1895
ISSN: 0028-0836,1476-4687
DOI: 10.1038/053032b0