Distribution of genetic diversity in wild European populations of prickly lettuce (Lactuca serriola): implications for plant genetic resources management

Genetic variation in Lactuca serriola, the closest wild relative of cultivated lettuce, was studied across Europe from the Czech Republic to the United Kingdom, using three molecular marker systems, simple sequence repeat (SSR, microsatellites), AFLP and nucleotide-binding site (NBS) profiling. The ‘functional’ marker system NBS profiling, targeting disease resistance genes of the NBS/LRR family, did not show marked differences in genetic diversity parameters to the other systems. The autogamy of the species resulted in low observed heterozygosity and high population differentiation. Intra-population variation ranged from complete homogeneity to nearly complete heterogeneity. The highest genetic diversity was found in central Europe. The SSR results were compared to SSR variation screened earlier in the lettuce collection of the Centre for Genetic Resources, the Netherlands (CGN). In the UK, practically only a single SSR genotype was found. This genotype together with a few other common SSR genotypes comprised a large part of the plants sampled on the continent. Among the ten most frequent SSR genotypes observed, eight were already present in the CGN collection. Overall, the CGN collection appears to already have a fair representation of genetic variation from NW Europe. The results are discussed in relation to sampling strategies for improving genebank collections of crop wild relatives

ECONOMICS OF ALTERNATIVE STOCKING DENSITIES FOR DIRECT-SEEDED CENTRAL MICHIGAN ALFALFA PASTURES

A framework which permits estimation of economically optimal stocking rates for alternative economic parameters and alfalfa forage availability was developed and applied to a controlled grazing experiment conducted with Holstein steers (243 kg) placed on direct seeded alfalfa pastures in Central Michigan. Responses of ADG to alternative levels of forage availability per standard livestock unit (FA) were summarized by a quadratic function and the associated gains/ha were calculated. The ADG decreased as standard stocking rate (SSR; SLU/ha) increased except for the combination of the lowest observed SSR and highest FA, where ADG was curvilinear as SSR increased. The trend for gain/ha was curvilinear for all FA. The SSR which maximized gain/ha increased with FA and was greater than that which maximized ADG. Net returns to fixed resources(NRFR)/ha ($/ha)were calculated for alternative SSR and the economically optimal SSR were identified under various levels of herbage mass (kg/d). The SSR's which maximized NRFR were between the SSR's which maximized ADG and gain/ha. The magnitude of the sale price discount for heavier weight calves (slide) influenced the economically optimal SSR and the sensitivity of net return to SSR. The economically optimal SSR increased as slide increased because animals stocked under higher SSR weighed less off pasture and therefore received less price discount.Crop Production/Industries,

SSR and post-conflict Reconstruction: armed wing of state-building?\ud

This paper directly challenges some of the popular Security Sector Reform (SSR) mythology that has grown around the UK’s involvement in Sierra Leone and the subsequent policy developments associated with SSR. It raises questions about the underlying political assumptions of the SSR process and contemporary SSR material, much of which lacks analysis of underlying theories of SSR relating to broader state-building and construction of a liberal peace. \ud \ud Using a case taken from the reconstruction of Sierra Leone, this paper outlines some of the key issues emerging after ten years of reconstruction efforts. Sierra Leone is usually over-cited, but given its importance to any orthodoxy that may be said to exist, it is relevant here. Fundamentally, Sierra Leone remains a relatively small state in West Africa and the fact a viable state remains elusive, challenges assumptions about time taken in reconstructing socio-political norms and structures, and also questions state-building as a post-conflict approach. \ud \ud This paper will argue that SSR in Sierra Leone was never a developed strategy but came to represent a series of policies that evolved on the ground largely as the result of the interaction of individuals and groups engaged in those early decisions, sometimes against the wishes of Whitehall, but always sharing a “direction of travel.” This is an important point in terms of how SSR policy was actually developed and also how approaches come to be seen as being far smoother and well planned with hindsight, but also in terms of how policy-makers and academics can learn about social, governance and security processes. \u

Understanding scaling through history-dependent processes with collapsing sample space

History-dependent processes are ubiquitous in natural and social systems. Many such stochastic processes, especially those that are associated with complex systems, become more constrained as they unfold, meaning that their sample-space, or their set of possible outcomes, reduces as they age. We demonstrate that these sample-space reducing (SSR) processes necessarily lead to Zipf's law in the rank distributions of their outcomes. We show that by adding noise to SSR processes the corresponding rank distributions remain exact power-laws, $p(x)\sim x^{-\lambda}$, where the exponent directly corresponds to the mixing ratio of the SSR process and noise. This allows us to give a precise meaning to the scaling exponent in terms of the degree to how much a given process reduces its sample-space as it unfolds. Noisy SSR processes further allow us to explain a wide range of scaling exponents in frequency distributions ranging from $\alpha = 2$ to $\infty$. We discuss several applications showing how SSR processes can be used to understand Zipf's law in word frequencies, and how they are related to diffusion processes in directed networks, or ageing processes such as in fragmentation processes. SSR processes provide a new alternative to understand the origin of scaling in complex systems without the recourse to multiplicative, preferential, or self-organised critical processes.Comment: 7 pages, 5 figures in Proceedings of the National Academy of Sciences USA (published ahead of print April 13, 2015

The Pawns of War: A Personal Account of the Attack on Verrères Ridge by The South Saskatchewan Regiment, 20 July 1944

A number of current books deal with Operations Goodwood and Atlantic, but scant attention has been paid to the 6th Canadian Infantry Brigade and its three regiments, the Queen’s Own Cameron Highlanders of Canada (CAM), the Fusiliers Mont-Royal (FMR) and the South Saskatchewan Regiment (SSR), and to the Essex Scottish Regiment which was attached to 6th Brigade during this operation. When our role has been discussed at all, historians have inferred that the SSR fled or withdrew in panic in this action. My role was as Commander “B” Company of the SSR, and later as Acting Commanding Officer (A/CO) of the SSR during this operation. I wish to record my memories of the battle supplemented by historical documentation which I hope will cause historians to review the 6th Brigade action of 20 July 1944