Temporal variations in space-time and progenitors of gamma ray burst and millisecond pulsars

A time varying space-time metric is shown to be a source of electromagnetic radiation. The post-Newtonian approximation is used as a realistic model of the connection between the space-time metric and a time varying gravitational potential. Large temporal variations in the metric from the coalescence of colliding black holes and neutron stars are shown to be possible progenitors of gamma ray burst and millisecond pulsars.Comment: Accept by International Journal of Modern Physics

A Simple Model of Rail Infrastructure Capacity and Costs.

The recent White Paper on "New Opportunities for the Railways" (Cm 2012, 1992) proposes that British Rail's responsibilities for operation and infrastructure will be separated. A new track authority, Railtrack, will be established and will operate without subsidy, except for capital grants in cases where a satisfactory cost-benefit return is achieved. It is acknowledged that these new arrangements will lead to some difficulties in allocating and charging for infrastructure, especially where rail infrastructure is congested, and consultants have been hired by Government to examine this issue. The principles that Government has specified should underly the access and charging regime are that it should: (a)Promote efficient operation (b)Promote competition and innovation (c)Encourage efficient use of infrastructure and other resources (d)Not discriminate unfairly between competing operators and services (e)Provide the means for financing Railtrack's infrastructure. The relevant theory is embodied in the literature concerning peak load pricing and optimal investment for public enterprises as expounded in standard text books (Turvey, 1971, Rees, 1984, Brown and Sibley, 1986.) and put into practice in most areas of the transport sector (eg Hansson and Nilsson, 1989, for rail, Small and Winston, 1988, for road, Bishop and Thompson, 1992, for air). The aim of this paper is not to make a contribution to this theory but to use it in conjunction with simple models of rail's infrastructure requirements and costs to highlight the key problems in infrastructure allocation and charging. The structure of this paper is as follows. In section two we consider a hypothetical rail line and the likely costs of different service levels. In section three, we relax the assumption that all trains are operated at the same speed and re-examine the likely costs of different service levels. In section 4, we go on to examine the pricing implications of our findings. In a final section, the implications of this analysis for policy are assessed

Management & sustainability of stockless organic arable and horticultural systems

The essential difference between stockless and stocked systems is that the fertility building clover ley and other “forage crops” are not processed through an animal but instead are grown as green manures which are returned directly to the soil by mulching, incorporation or occasionally through composting of the green manure. Stockless systems provide no opportunity for the creation of straw and animal manure based farm yard manure or compost. While there is no research evidence that the lack of animals or manure based compost affects overall soil fertility and crop yield, there is some research evidence that animal manure enhances soil mychorrizae populations and soil organic matter accumulation. This effect might also be seen from the use of plant based compost, sometimes sourced off-farm as “green waste” in stockless systems, but there is no comparative work available. While the use of manures has the advantage of allowing movement of fertility around the farm within a rotation, grazing animals have the drawback of uneven dispersal of manure and urine and manure storage is liable to poor management and loss of nutrients. Green manures are fundamental to stockless systems, both as one or two year crops which are either mulched or incorporated or grown as short term catch crops or undersown crops. With appropriate selection and management of green manures there is potential for enhanced fertility building over that which is possible with grazed leys. The practical commercial experience of farmers using stockless rotations is stronger than the research would suggest in terms of supporting its technical success and viability. Weed control remains a serious problem for arable farms which requires very high standards of management. The demand for organic livestock products is increasing and the area of organic land producing feed grains is insufficient to support the required expansion. World demand for organic grains is increasing. The introduction of livestock on to specialist conventional cereal producing farms in many instances requires prohibitively expensive infrastructure costs. Stockless rotations utilising green manures to fix nitrogen as part of the rotation provide a technically feasible and profitable alternative. Stockless horticultural systems operated with or without the use of imported manure or compost offer potential for technically and financially viable systems provided that there is an appropriate balance of fertility building green manures and cash crops

Inequality and income gaps

This paper discusses inequality orderings based explicitly on closing up of income gaps, demonstrating the links between these and other orderings, the classes of functions preserving the orderings and applications showing their usefulness in comparison of economic policies

The physiological aspects of traumatic shock

Thesis (M.A.)--Boston UniversityThe condition known as shock has been recognized and described by the medical profession for a great many years. Cannon (1923) proposed the descriptive term "exemia," originally applied to a similar condition by Hippocrates. The word shock probably was first used by Latta (1795). Since then there have been many attempts to supply an adequate definition and an explanation for the fatal tendencies ot the condition. In a final explanation of shock there probably will be incorporated much of the knowledge now known. This cause of shock may not be one definite factor but may consist of several factors. Much of the present knowledge has been found to be grossly inadequate in the explanation of other shock-like conditions