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Using a comprehensive data set on (surviving and non-surviving) UK mutual funds (April 1975 – December 2002), we use a bootstrap methodology to distinguish between 'skill' and 'luck' for individual funds. This methodology allows for non-normality in the idiosyncratic risks of the funds – a major issue when considering those funds which appear to be either(More)
Free Ca2+ in the cytosol ([Ca2+]i) of individual rat ventricle cells injected with aequorin was measured under anoxia. In glucose-free medium myocytes spontaneously shortened after about 60 min, although [Ca2+]i was still at or near resting levels. However, within minutes a net inward movement of Ca2+ across the sarcolemma developed and [Ca2+]i began to(More)
This paper presents mathematical models for the hepatocyte calcium oscillator which follow the concepts in a class of informal models developed to account for the striking dependence on the receptor type of several features of the calcium oscillations, in particular the shape and duration of the free calcium transients. The essence of these models is that(More)
In the stressed animal, the vasoactive hormones vasopressin and angiotensin-II and the neurotransmitter noradrenaline induce liver cells to release glucose from glycogen. The intracellular signal that links the cell-surface receptors for noradrenaline (alpha 1) and vasoactive peptides to activation of glycogenolysis is known to be a rise in the cytoplasmic(More)
The parthenogenetic activation of mouse oocytes by several agents is accompanied by a large rise in the intracellular calcium concentration ( [Ca2+]i). The tumour-promoting phorbol ester 12-O-tetradecanoyl phorbol acetate (TPA) activates some cellular processes which are also activated by raised [Ca2+] (ref. 2). We therefore tested TPA on mouse oocytes and(More)
As new techniques are developed to measure intracellular messengers it becomes increasingly apparent that there is a remarkable spatial and temporal organization of cell signalling. Cells possess a small discrete hormone-sensitive pool of inositol lipid. In some cells such as Xenopus oocytes and Limulus photoreceptors this phosphoinositide signalling system(More)
Calcium has an important role in the events of egg activation and early preimplantation development. We investigated changes in intracellular calcium concentration in human oocytes at fertilization using the calcium-sensitive photoprotein aequorin. Oocytes were donated for research by patients undergoing in-vitro fertilization treatment in the Department of(More)