Block’s lemma states that the numbers m of point-classes and n of block-classes in a tactical decomposition of a 2-(v, k, λ) design with b blocks satisfy m ≤ n ≤ m+ b− v. We present a strengthening of the upper bound for the case of Steiner systems (2-designs with λ = 1), together with results concerning the structure of the block-classes in both extreme cases. Applying the results to the Stein...

Neurogenesis persists in the hippocampal dentate gyrus of mammals, including human and nonhuman primates, throughout life (Altman and Das, 1965; Cameron et al., 1993; Kuhn et al., 1996; Eriksson et al., 1998; Gould et al., 1999; Kornack and Rakic, 2001). Neural stemlike cells reside in the subgranular zone (SGZ) at the border of the hilus and DGC layer (Seri et al., 2001; Filippov et al., 2003)...

Cameron introduced a natural probability measure on the set S of sum-free sets, and asked which sets of sum-free sets have a positive probability of occurring in this probability measure. He showed that the set of subsets of the odd numbers has a positive probability, and that the set of subsets of any sum-free set corresponding to a complete modular sum-free set also has a positive probability...

Generalized t-designs, which form a common generalization of objects such as tdesigns, resolvable designs and orthogonal arrays, were defined by Cameron [P.J. Cameron, A generalisation of t-designs, Discrete Math. 309 (2009), 4835–4842]. In this paper, we define a related class of combinatorial designs which simultaneously generalize packing designs and packing arrays. We describe the sometimes...

Barrett’s esophagus is well recognized as a premalignant condition leading to higher incidence of esophageal adenocarcinoma than the general population (Cameron, 1995; Katz, 1998; Solaymani-Dodaran, 2004). The risk of esophageal adenocarcinoma is approximately 30 times greater in patients with Barrett’s esophagus as compared with the general population (SolaymaniDodaran, 2004). Barrett’s esopha...

This paper describes occurrences of low grade, disseminated gold in sedimentary rocks and alkalic intrusions in the vicinity of the Howell Creek Structure (HCS; Price,1964) of southeastern British Columbia. The study is part of the B.C. Geological Survey’s ongoing Sediment-hosted Gold Project, which is examining occurrences throughout the province which may have similarities to gold deposits in...

PAPILLOEDEMA occurring in association with pulmonary emphysema was first described by Cameron (1933). Simpson (1948) reporting three cases, thought it rare. Westlake and Kaye (1954) reported three cases in twelve emphysematous subjects, ten of whom had raised intracranial pressure. Flint (1954), describing the clinical features of a series of patients with cor pulmonale most of whom had emphyse...

Suppose that T is a map of the Wiener space into itself, of the following type: T = I + u where u takes its values in the Cameron-Martin space H. Assume also that u is a finite sum of H-valued multiple Ito-Wiener integrals. In this work we prove that if T preserves the Wiener measure, then necessarily u is in the first Wiener chaos and the transformation corresponding to it is a rotation in the...

Cameron's proof of this result is based on Sims' Conjecture, which has only been shown to hold using the classification of finite simple groups. In the final section of [1], Cameron indicates how Theorem 1 might be proved in an elementary fashion using Macpherson's classification of infinite distance-transitive graphs of finite valency [4]. Corollary 1 below provides the missing portion of this...

In Britain, peptic ulceration is the commonest cause of upper gastrointestinal haemorrhage. Although carcinoma of the stomach and ruptured oesophageal varices together account for only a small proportion of cases, early differentiation of the causal lesion is important from the point of view of treatment. As the seromucoid fraction of the serum polysaccharides is raised in cancer (Winzler and S...