Sudden death, during or just after labour, has only too often been attributed to " obstetric shock." Out of this aetiological obscurity, in 1941 and 1942, Steiner and Lushbaugh extracted one recognizable cause of death, the finding in the maternal blood vessels of amniotic material. Recognition of other cases has followed rapidly (see review by Sluder and Lock, 1952), but thus far only three re...

We define and study the symmetric version of differential torsion theories. We prove that the symmetric versions of some of the existing results on derivations on right modules of quotients hold for derivations on symmetric modules of quotients. In particular, we prove that the symmetric Lambek, Goldie and perfect torsion theories are differential. We also study conditions under which a derivat...

A d-dimensional RCA(1) process is a generalization of the d-dimensional AR(1) process, such that the coefficients {Mt; t = 1, 2,. . .} are i.i.d. random matrices. In the case d = 1, under a nondegeneracy condition, Goldie and Maller gave necessary and sufficient conditions for the convergence in distribution of an RCA(1) process, and for the almost sure convergence of a closely related sum of r...

E. Rod Butchers Network Logistics, Air New Zealand Ltd. Private Bag 92007, Auckland, New Zealand Paul R. Day Optimal Decision Technologies Ltd. P.O. Box 128-233, Remuera, Auckland, New Zealand Andrew P. Goldie Optimal Decision Technologies Ltd. Stephen Miller Network Logistics, Air New Zealand Ltd. Jeff A. Meyer Optimal Decision Technologies Ltd. David M. Ryan Department of Engineering Science,...

If R is a commutative ring, then we prove that every finitely generated R-module has a pure-composition series with indecomposable cyclic factors and any two such series are isomorphic if and only if R is a Bézout ring and a CF-ring. When R is a such ring, the length of a pure-composition series of a finitely generated R-module M is compared with its Goldie dimension and we prove that these num...