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

“All May Visit the Big Camp”: Race and the Lessons of the Civil War at the 1913 Gettysburg Reunion

Shaping historical memory means extracting lessons from the past. Those lessons frame the debate about the nature of the present. Just months after the inauguration of Woodrow Wilson, the attention of most of the nation focused on the events scheduled to commemorate the semi-centennial of what was by then increasingly viewed as “the turning point” of the Civil War. The reunion at Gettysburg in 1913 constituted the contemporary public exegesis of the status of American memory of the Civil War. In this respect, the reunion in Gettysburg reflected the erasure of the legacy of emancipation and the unfulfilled promise of equality for African-Americans. Yet, almost all the public discourse at Gettysburg reflected no sense of disappointment; rather, the battle now represented a triumph of the American spirit. The presence of AfricanAmerican veterans would have complicated the message of white reconciliation at the reunion. Reckoning with the honorable service of black troops was not something mainstream American society felt comfortable with in 1913. Whether or not black veterans attended the fiftieth anniversary of Gettysburg is a small detail which illuminates a profoundly broader pair of subjects: the meaning of the Civil War and the nature of American race relations in 1913. In answering this question of black veterans at the Gettysburg reunion, the broader context of the organization and execution of the reunion, the lessons drawn from the ceremonies in Gettysburg, explicit discussions of race at the reunion and contemporary African-American perspectives must all be explored. [excerpt

Variational Theory of Balance Systems

In this work we apply the Poincare-Cartan formalism of the Classical Field Theory to study the systems of balance equations (balance systems). We introduce the partial k-jet bundles of the configurational bundle and study their basic properties: partial Cartan structure, prolongation of vector fields, etc. A constitutive relation C of a balance system is realized as a mapping between a (partial) k-jet bundle and the extended dual bundle similar to the Legendre mapping of the Lagrangian Field Theory. Invariant (variational) form of the balance system corresponding to a constitutive relation C is studied. Special cases of balance systems -Lagrangian systems of order 1 with arbitrary sources and RET (Rational Extended Ther- modynamics) systems are characterized in geometrical terms. Action of auto- morphisms of the configurational bundle on the constitutive mappings C is studied and it is shown that the symmetry group Sym(C) of C acts on the sheaf of solutions Sol(C) of he balance system. Suitable version of Noether Theorem for an action of a symmetry group is presented together with the special forms for semi- Lagrangian and RET balance systems and examples of energy momentum and gauge symmetries balance laws

Being a manager in an English nursery

This article draws on interviews with 29 managers and deputy managers within 15 nurseries in the private sector in England. The author argues that, whilst there is a growing literature on management and professionalism within the Early Years (EY) sector, there is less known about the actual experiences of being a manager in this context. Many of the individuals who are promoted into a management role did not, until recently, have the training to support them. Whilst individuals are being encouraged to participate in the managerial roles now demanded by the professionalisation agenda, it could be argued that the traditional EY workforce are primarily motivated by a strong desire to work with children. Even if their own employer provides in-house management training or the opportunity to participate in national schemes such as EYPS, these young women, like many professionals becoming managers, move away from what they like doing best – working with the client/children. The research outlined in this paper explores these issues by relaying individuals’ stories of what it is like to be a manager in the EY context