General properties of cosmological models with an Isotropic Singularity

Much of the published work regarding the Isotropic Singularity is performed under the assumption that the matter source for the cosmological model is a barotropic perfect fluid, or even a perfect fluid with a $\gamma$-law equation of state. There are, however, some general properties of cosmological models which admit an Isotropic Singularity, irrespective of the matter source. In particular, we show that the Isotropic Singularity is a point-like singularity and that vacuum space-times cannot admit an Isotropic Singularity. The relationships between the Isotropic Singularity, and the energy conditions, and the Hubble parameter is explored. A review of work by the authors, regarding the Isotropic Singularity, is presented.Comment: 18 pages, 1 figur

Natural scene statistics and the structure of orientation maps in the visual cortex

Visual activity after eye-opening influences feature map structure in primary visual cortex (V1). For instance, rearing cats in an environment of stripes of one orientation yields an over-representation of that orientation in V1. However, whether such changes also affect the higher-order statistics of orientation maps is unknown. A statistical bias of orientation maps in normally raised animals is that the probability of the angular difference in orientation preference between each pair of points in the cortex depends on the angle of the line joining those points relative to a fixed but arbitrary set of axes. Natural images show an analogous statistical bias; however, whether this drives the development of comparable structure in V1 is unknown. We examined these statistics for normal, stripe-reared and dark-reared cats, and found that the biases present were not consistently related to those present in the input, or to genetic relationships. We compared these results with two computational models of orientation map development, an analytical model and a Hebbian model. The analytical model failed to reproduce the experimentally observed statistics. In the Hebbian model, while orientation difference statistics could be strongly driven by the input, statistics similar to those seen in experimental maps arose only when symmetry breaking was allowed to occur spontaneously. These results suggest that these statistical biases of orientation maps arise primarily spontaneously, rather than being governed by either input statistics or genetic mechanisms

A Gendered Imperative: Does Sexual Violence Attract UN Attention in Civil Wars?

There is increasing awareness that sexual violence is distinct from other aspects of civilian victimization in civil wars. Few studies have examined the independent impact of such violence on responses to civil wars as compared to “traditional” forms of violence. This paper explores whether reports of high levels of rape and sexual violence increase the probability of UN attention to conflicts and calls to action. In so doing, we combine original data on UN Security Council resolutions with data on sexual violence in armed conflict and estimate the impact of sexual violence on UN attention to all civil wars from 1990-2009. We show that the effects of sexual violence on the number and level of UNSC resolutions are shown to be significant even when controlling for other important determinants of UN action. These findings have important implications for understanding how the UN has expanded its view on protecting civilians

Visual Representation of the TOGAF Requirements Management Process

International audienc

A virtual environment to re-create the auditory and visual hallucinations of psychosis

Psychosis is a mental disorder which affects 1-2% of the population at some point in their lives. This project aims to develop a virtual environment to simulate the experience of psychosis, focusing on re-creating the auditory and visual hallucinations. A virtual psychiatric ward environment has been constructed and the psychosis simulation software has been written to implement the hallucinations of two patients. A patient who viewed her re-created psychotic experiences was very impressed, and commented that the simulation re-created the same emotions that she had experienced on a day-to-day basis during her psychotic episodes. This is essential if the software is to be used as an educational tool about psychosis