Density fluctuations and the structure of a nonuniform hard sphere fluid

We derive an exact equation for density changes induced by a general external field that corrects the hydrostatic approximation where the local value of the field is adsorbed into a modified chemical potential. Using linear response theory to relate density changes self-consistently in different regions of space, we arrive at an integral equation for a hard sphere fluid that is exact in the limit of a slowly varying field or at low density and reduces to the accurate Percus-Yevick equation for a hard core field. This and related equations give accurate results for a wide variety of fields

Improved AURA k-Nearest Neighbour approach

The k-Nearest Neighbour (kNN) approach is a widely-used technique for pattern classification. Ranked distance measurements to a known sample set determine the classification of unknown samples. Though effective, kNN, like most classification methods does not scale well with increased sample size. This is due to their being a relationship between the unknown query and every other sample in the data space. In order to make this operation scalable, we apply AURA to the kNN problem. AURA is a highly-scalable associative-memory based binary neural-network intended for high-speed approximate search and match operations on large unstructured datasets. Previous work has seen AURA methods applied to this problem as a scalable, but approximate kNN classifier. This paper continues this work by using AURA in conjunction with kernel-based input vectors, in order to create a fast scalable kNN classifier, whilst improving recall accuracy to levels similar to standard kNN implementations

Divine competition: Religious organizations and service provision in India

This paper examines religious and non-religious service provision by religious organisations in India. We present a stylized Hotelling-style model in which two religious organisations differentiate hemselves on the strength of religious beliefs in order to compete in attracting adherents. We show in the model two central predictions: first,that the organisations will differentiate themselves on the strength of religious beliefs. Second, that in equilibrium, economic inequality makes the organisations increase their provision of non-religious services. To test this, we present unique primary survey dataon the economics of religion, collected by us between 2006 and 2010 from 568 Hindu, Muslim, Christian, Sikh and Jain religious organisations spread across 7 Indian states. We use these data to demonstrate that the organisations have substantially increasedtheir provision of non-religious services. We also provide quantitative evidence based oneconometric testing to highlight that religious organisations are differenting themselves on the strength of religious beliefs with respect to other organisations, and are also providing higher education and health services as economic inequality increases in India

Satellite-observed vegetation as an indicator of climate variability over southern Africa

The satellite-derived normalised difference vegetation index (NDVI) offers new opportunities to assess the impact of year-to-year climate fluctuations. In this study the NDVI is mapped over southern Africa for the period 1981-1994. Sharp upward and downward trends follow the cycle of summer flood and drought. January to March NDVI values are correlated at +0.82 with harvested maize yield for the North West Province of central South Africa. Departures of late summer NDVI from the historical mean illustrates the distribution and intensity of the influence of the Southern Oscillation, in alternating seasons of vegetative growth and depletion. The first principal component of the NDVI field time series contains a broad signal covering all of Africa south of 15 degrees S, and appears related to the low frequency component of the global El Nino phenomenon

The shape of equality: discourses around the Section 28 repeal in Scotland

This article focuses on conceptualizations of equality in the discourses deployed in the campaign to repeal Section 28 in Scotland. I use the parliamentary debates and two newspapers: the Daily Record, which supported the campaign to Keep the Clause, and The Guardian, which supported repeal, to exemplify the different discursive articulations around equality and citizenship. I suggest that the Scottish example provides further evidence of the ways in which liberalism naturalizes heterosexuality as the standard for citizenship and thus bequeaths a hierarchy of 'equality' and citizenship in the realm of sexuality, wherein lesbian and gay citizenship is either rendered invalid or characterized as 'special rights'. However, within the narrow confines of the parliamentary debates, more expansive and differentiated notions of citizenship and equality are evident. Whilst I conclude that the 'shape' of equality achieved through the repeal has been moulded to support institutionalized heterosexuality - with Section 28 replaced by statutory guidelines on sex education which advocate marriage - I also suggest equality is contested, both through the recognition of transformations in heterosexual family forms and the appeal to non-discrimination as a democratic principle. It is possible, therefore, that current destabilizations of the heterosexual social order simultaneously destabilize the precepts of liberal democracy

Description of the fluctuating colloid-polymer interface

To describe the full spectrum of surface fluctuations of the interface between phase-separated colloid-polymer mixtures from low scattering vector q (classical capillary wave theory) to high q (bulk-like fluctuations), one must take account of the interface's bending rigidity. We find that the bending rigidity is negative and that on approach to the critical point it vanishes proportionally to the interfacial tension. Both features are in agreement with Monte Carlo simulations.Comment: 5 pages, 3 figures, 1 table. Accepted for publication in Phys. Rev. Let

Ringing the eigenmodes from compact manifolds

We present a method for finding the eigenmodes of the Laplace operator acting on any compact manifold. The procedure can be used to simulate cosmic microwave background fluctuations in multi-connected cosmological models. Other applications include studies of chaotic mixing and quantum chaos.Comment: 11 pages, 8 figures, IOP format. To be published in the proceedings of the Cleveland Cosmology and Topology Workshop 17-19 Oct 1997. Submitted to Class. Quant. Gra

Supernovae observations and cosmic topology

Two fundamental questions regarding our description of the Universe concern the geometry and topology of its 3-dimensional space. While geometry is a local characteristic that gives the intrinsic curvature, topology is a global feature that characterizes the shape and size of the 3-space. The geometry constrains, but does not dictate the the spatial topology. We show that, besides determining the spatial geometry, the knowledge of the spatial topology allows to place tight constraints on the density parameters associated with dark matter ($\Omega_m$) and dark energy ($\Omega_{\Lambda}$). By using the Poincar\'e dodecahedral space as the observable spatial topology, we reanalyze the current type Ia supenovae (SNe Ia) constraints on the density parametric space $\Omega_{m} - \Omega_{\Lambda}$. From this SNe Ia plus cosmic topology analysis, we found best fit values for the density parameters, which are in agreement with a number of independent cosmological observations.Comment: 5 pages, 2 figures. Minor changes and a ref. added. To appear in A&A (2006

Culture-independent bacterial community profiling of carbon dioxide treated raw milk

Due to technical simplicity and strong inhibition against the growth of psychrotrophic bacteria in milk, CO treatment has emerged as an attractive processing aid to increase the storage time of raw milk before downstream processing. However, it is yet to be adopted by the industry. In order to further explore the suitability of CO treatment for raw milk processing, the bacterial populations of carbonated raw milk collected locally from five different sources in Australia were analysed with next-generation sequencing. Growth inhibition by CO was confirmed, with spoilage delayed by at least 7\ua0days compared with non-carbonated controls. All non-carbonated controls were spoiled by Gammaproteobacteria, namely Pseudomonas fluorescens group bacteria, Serratia and Erwinia. Two out of the five carbonated samples shared the same spoilage bacteria as their corresponding controls. The rest of the three carbonated samples were spoiled by the lactic acid bacterium (LAB) Leuconostoc. This is consistent with higher tolerance of LAB towards CO and selection of LAB in meat products stored in CO-enriched modified atmosphere packaging. No harmful bacteria were found to be selected by CO. LAB are generally regarded as safe (GRAS), thus the selection for Leuconostoc by CO in some of the samples poses no safety concern. In addition, we have confirmed previous findings that 454 pyrosequencing and Illumina sequencing of 16S rRNA gene amplicons from the same sample yield highly similar results. This supports comparison of results obtained with the two different sequencing platforms, which may be necessary considering the imminent discontinuation of 454 pyrosequencing