Dilaton Stabilization in Brane Gas Cosmology

Brane Gas Cosmology is an M-theory motivated attempt to reconcile aspects of the standard cosmology based on Einstein's theory of general relativity. Dilaton gravity, when incorporating winding p-brane states, has verified the Brandenberger--Vafa mechanism --a string-motivated conjecture which explains why only three of the nine spatial dimensions predicted by string theory grow large. Further investigation of this mechanism has argued for a hierarchy of subspaces, and has shown the internal directions to be stable to initial perturbations. These results, however, are dependent on a rolling dilaton, or varying strength of Newton's gravitational constant. In these proceedings we show that it is not possible to stabilize the dilaton and maintain the stability of the internal directions within the standard Brane Gas Cosmology setup.Comment: 6 pages, no figures. To appear in the Proceedings of MRST 2004, held at Concordia University, Montreal, QC, 12-14 May 200

Leeds Met Library Facebook application

At the Leeds Met staff development festival in 2008 a library graduate trainee, Anna Hepworth, took part in a ‘Dragons’ Den’ event which saw staff propose new, innovative ideas to a panel of senior managers. Anna’s suggestion was to develop a Facebook application (or ‘app’) for the library and it was one of the competition winners. Anna’s initial proposal was to create a Leeds Met library catalogue application, but after discussions with members of the library’s ‘technologies for learning’ team it was decided to take the application a stage further, creating a mash-up using data from the library management system (Sirsi-Dynix Symphony). The Facebook application would send a library catalogue search box to a Facebook profile, but would also add value by delivering customised user data, including library record details such as number of issues, reservations and overdues. There would also be links to the library website and online self-service functions from the application

A detective story: emphatics in Mehri

Until 1970, Ethio-Semitic was believed to be the only Semitic language sub-family in which the main correlate of “emphasis” is glottalization, a feature said at the time to be due to Cushitic influence. Since the work of T.M. Johnstone, however, it has been argued that glottalization is a South Semitic feature, attested not only in Ethio-Semitic, but also in the Modern South Arabian languages. Two statements in the literature on Modern South Arabian, however, suggested to us that the original evidence needed to be re-investigated: first, some of the “ejectives” are described as at least partially voiced, not a phonetic impossibility, but so far unheard of in the phonological system of any language; and secondly, the degree of glottalization is frequently described as dependent on the phonological environment, although details of the environment in which emphatics are always realized as ejectives are not given. In this paper, we consider acoustic data from Mahriyōt (a Mehri dialect spoken in the easternmost province of Yemen), we examine descriptions of emphatics in other dialects of Mehri and other Modern South Arabian languages, we look at phonological environments in which emphatics are realized as ejectives and those in which they are not, and we conclude that the file on emphasis in these languages needs to be re-opened to fresh judgement

Nutrient budgets on organic farms: a review of published

This report was presented at the UK Organic Research 2002 Conference. On organic farms it is important that a balance between inputs and outputs of nutrients is achieved. This paper collates nutrient budgets collated at the farm scale for 88 farms in 9 temperate countries. The majority of budgets were compiled for dairy farms (56). All the nitrogen budgets showed an N surplus (average 83 kg N ha-1 year-1). The phosphorus (P) and potassium (K) budgets showed both surpluses and deficits (average 3.4 kg P ha-1 year-1; 13.7 kg K ha-1 year-1). For all nutrients as nutrient inputs increased the surplus increased more significantly than the nutrient outputs. Overall, the data illustrate the diversity of management systems in place on organic farms, which consequently lead to significant variability in nutrient use efficiency and potential nutrient sustainability between farms. There are opportunities for almost all organic farmers to improve the efficiency of nutrient cycling on the farm and increase short-term productivity and long-term sustainability

Multidimensional Epistasis and the Advantage of Sex

Kondrashov and Kondrashov (2001) suggest that there is usually a disadvantage for sex in systems with multidimensional epistasis. They define systems of 'unidimensional epistasis' to be those where the fitness of a genotype is a function of the number of mutations it carries, and in contrast describe a system where the fitness of a genotype is a function of the numbers of mutations in two (or more) disjoint subsets of loci creating 'multidimensional epistasis'. In an example landscape an asexual population evolves fit genotypes about twice as fast as a sexual one. Here we examine other landscapes with multidimensional epistasis and find cases where an asexual population evolves fit genotypes 20 and 180 times slower than a sexual population