We study the cancellation of U (1) anomalies in Type I and Type IIB D = 4, N = 1 string vacua. We first consider the case of compact toroidal Z N Type IIB orientifolds and then proceed to the non-compact case of Type IIB D3 branes at orbifold and orientifold singularities. Unlike the case of the heterotic string we find that for each given vacuum one has generically more than one U (1) with non...

SIR,-Further to the interesting leading article "Nutrition and Sleep" (20 May, p. 418) one may ask whether sleep is not the "natural" state and wakefulness merely a res,pite for the satisfaction of instinctual (and socially inculcated) drives. The hibernating animal is unlikely to chance upon dangerous predators. On this model the satisfqction of drives would lead to sleep and their continued f...

M(atrix) theory on an orbifold and classical two-branes therein are studied with particular emphasis to heterotic M(atrix) theory on S1=Z2 relevant to strongly coupled heterotic and dual Type IA string theories. By analyzing orbifold condition on Chan-Paton factors, we show that three choice of gauge group are possible for heterotic M(atrix) theory: SO(2N), SO(2N + 1) or USp(2N). By examining a...

BROWN, S.S., FORREST, J.A.H. & ROSCOE, P. (1972) A controlled trial of fructose in the treatment of acute alcoholic intoxication. Lancet, ii, 898. KAYE, S. & HAAG, H.B. (1957) Terminal blood alcohol concentrations in ninety-four fatal cases of acute alcoholism. Journal of the American Medical Association, 165, 451. LAURIE, W. (1971) Alcohol as a cause of sudden unexpected death. Medical Journal...

This lecture is about the history of the purinergic signalling concept. It begins with reference to the paper by Paton & Vane published in 1963, which identified non-cholinergic relaxation in response to vagal nerve stimulation in several species, although they suggested that it might be due to sympathetic adrenergic nerves in the vagal nerve trunk. Using the sucrose gap technique for simultane...

Activation of the NMDA subtype of glutamate receptor has been implicated in structural synaptic plasticity in many developing sensory systems. In the frog retinotectal system, chronic exposure of the optic tectum to NMDA, which decreases the effectiveness of NMDA receptors (Debski et al., 1991), results in the pruning of the branches of retinal terminal arbors (Cline and Constantine-Paton, 1990...

disease includes the following observations, but their significance is not yet clear: (1) There is evidence of a connection between abnormal glucose tolerance and post' encephalitic Parkinson's disease (Gillhespy and Paton, i960; Terrana and Adragn^ 1951). McCowan, Harris and Mann (1926) give glucose tolerance curves for a group of patients with post-encephalitic Parkinsonism which are clearly ...

NMDA receptor subunit changes have an important implication in synaptic development, learning, memory, and neuronal disorders. Previous studies have suggested that two membrane-associated guanylate kinase (MAGUK) family scaffolding proteins, SAP102 and PSD-95, are involved in the switch from predominance of NMDA receptors rich in NR2B subunits to that of NMDA receptors rich in NR2A subunits. No...

New string dynamics is formulated on the basis of the extended set of supergauge constraints including not only supergauge Vira-soro conditions but also nilpotent supercurrent constraints. This approach arises from a natural generalization of the classical operator many-string vertices. The formulation of this model leads to three two-dimensional surfaces for description of hadron strings. It g...

The work reported in this extended abstract has evolved from research concerned with the characterisation of domains for the development of knowledge based systems (KBSs) (Paton et al, 1991 and 1993). It has long been recognised that knowledge acquisition is a key stage in the construction of a KBS but also that it presents a major hurdle to a designer. We had sought to approach this problem by...