Edmonds and Giles introduced the class of box totally dual integral polyhedra as a generalization of submodular flow polyhedra. In this paper a geometric characterization of these polyhedra is given. This geometric result is used to show that each TDI defining system for a box TDI polyhedron is in fact a box TDI system, that the class of box TDI polyhedra is in co-NP and is closed under taking ...

Calcium dichloride tetra urea was prepared by the reaction of calcium chloride with urea in aqueous solution. The crystals are monoclinic, a= 7.633, b= 12.45 1, c= 8.118 ?,? = 113.17, Z = 4, space group P 2,/a. The crystal structure was determined by single crystal X-ray methods and refined to R= 0.041. The calcium atoms are coordinated to four oxygen atoms of urea and to two chloride ions....

Environ. Entomol. 23(2): 211-219 ABSTRACT The first field study of a genetically altered virus in the United States was performed with an isolate of the Autographa californica nuclear polyhedrosis virus (AcMNPV), which lacks a polyhedrin gene. In the first year of the study, three applications of 7.4 x 1011 AcMNPV polyhedra containing 48% genetically altered and 52% wild-type virus particles (c...