The death of Colonel Paul Bush, which occurred on the 7th October, at the age of 73, deprived Bristol of a publicspirited citizen, and the medical profession of a popular and distinguished member. Throughout his life he devoted a great deal of time and energy to public services and to the promotion of various organizations apart from his hospital or private practice, and it was characteristic o...

We establish a numerically explicit version of the Pólya–Vinogradov inequality for the sum of values of a Dirichlet character on an interval. While the technique of proof is essentially that of Landau from 1918, the result we obtain has better constants than in other numerically explicit versions that have been found more recently. – Dedicated to Mel Nathanson on his 65th birthday

A finite subset A of an abelian group G is said to be zero-free if the identity element of G cannot be written as a sum of distinct elements from A. In this article we study the structure of zero-free subsets of Z/pZ, the cardinalities of which are close to the largest possible. In particular, we determine the cardinality of the largest zero-free subset of Z/pZ, when p is a sufficiently large p...

in order to evaluate the intercropping of corn (zea mays l.) and bean cultivars (phaseolus spp.) an experiment was carried out in a randomized complete block design with three replicaties at sari agricultural sciences and natural resources university during growing season of 2010. the experimental treatments consisted of sole cropping of corn, white bean, bush bean, red bean, pinto bean and swo...

Global changes, such as increased temperatures and elevated CO2, are driving shifts in plant species distribution and dominance, like woody plant encroachment into grasslands. Local factors within these ecotones can influence the rate of regime shifts. Woody encroachment is occurring worldwide, though there has been limited research within coastal systems, where mangrove (woody shrub/tree) stan...

In many cultural landscapes, the abandonment of traditional grazing leads to encroachment of pastures by woody plants, which reduces habitat heterogeneity and impacts biodiversity typical of semi-open habitats. We developed a framework of mutually interacting spatial models to locate areas where shrub encroachment in Alpine treeline ecosystems deteriorates vulnerable species' habitat, using bla...

Does knowledge matter ? There are actually at least two questions behind this broad one. The first is whether the value of knowledge is independent from other epistemic values, such as the value of truth, or the value of having true beliefs. The second is whether knowledge, as an epistemic value is independent from other values, such as the good or freedom, which are practical or ethical values...

This is Part II of the two-part feature on Paul Erdős following his centennial. Part I had contributions from Krishnaswami Alladi and Steven G. Krantz, Vera T. Sós and László Lovász, Ronald Graham and Joel Spencer, Jean-Pierre Kahane, and Mel Nathanson. Here in Part II we have six articles from contributors Noga Alon, Dan Goldston, András Sárközy, József Szabados, Gérald Tenenbaum, and Stephan ...

We introduce a method for extracting information about human hands present in colour images largely based on work done by Daniel Heckenberg and Brian Lovell. It relies heavily on isolating the hand in the image using a statistical model of skin colour. Following this, it employs solely imagebased techniques to determine the locations of the fingers, and performs a simplistic gesture recognition...