On the Behaviour and Stability of Superconducting Currents

We present analytic and numerical results for the evolution of currents on superconducting strings in the classical $U(1) \times U(1)$ model. We derive an energy functional for the currents and charges on these strings, establishing rigorously that minima should exist in this model for loops of finite size (vortons) if both charge and current are present on the worldsheet. We then study the stability of the currents on these strings, and we find an analytic criterion for the onset of instability (in the neutral limit). This limit specifies a lower maximal current than previous heuristic estimates. We conclude with a discussion of the evolution of loops towards their final vorton state in the model under consideration.Comment: 18 pages, 6 figures. To be submitted to Nuclear Physics

Drum vortons in high density QCD

Recently it was shown that high density QCD supports of number of topological defects. In particular, there are U(1)_Y strings that arise due to K^0 condensation that occurs when the strange quark mass is relatively large. The unique feature of these strings is that they possess a nonzero K^+ condensate that is trapped on the core. In the following we will show that these strings (with nontrivial core structure) can form closed loops with conserved charge and currents trapped on the string worldsheet. The presence of conserved charges allows these topological defects, called vortons, to carry angular momentum, which makes them classically stable objects. We also give arguments demonstrating that vortons carry angular momentum very efficiently (in terms of energy per unit angular momentum) such that they might be the important degrees of freedom in the cores of neutron stars.Comment: 11 pages, accepted for publication in Physical Review

Interannual population dynamics of the green spruce aphid Elatobium abietinum (Walker) in France

The hypothesis that similar processes govern interannual dynamics of green spruce aphid in the UK and France, is generally supported by the application of a general discrete model. A simple model based on relatively few parameters was able to closely characterise interannual population dynamics from completely independent aerial and arboreal samples of aphids. Long term field population estimates of the green spruce aphid Elatobium abietinum (Walker) in France have provided the opportunity to select and evaluate the generality of a model which was developed in the UK to explain the year‐to‐year variations in peak abundance of the aphid. Aims The objective was to observe the influence of the local climates and disturbing climate factors on the population densities of the insect in two regions of France. Methods The model uses climate variables and aphid population data from regular samples in the two regions that were investigated. A general discrete model was used to predict aphid population densities. Results The model performed well in tracking the interannual patterns of population but was less likely to predict absolute population density. Conclusion To improve predictions, further account would need to be taken of additional site‐specific climate variables and the strength of overcompensating density dependence. Nevertheless it is clear that broadly similar processes are at work in the population dynamics of this insect across its biogeographical range

Lifestyle gambling, indebtedness and anxiety: A deviant leisure perspective

While once subject to wide-ranging state control, gambling has successfully culturally embedded itself within the normalised and legitimised forms of leisure such as the night-time economy, sports fandom and online forums of socialisation. Consequently, this article argues that existing research which conceptualises gambling as separate from everyday life is largely obsolete in the contemporary context. We argue here that gambling has become an integral feature of the wider masculine weekend leisure experience, intimately connected to an infantilised consumer identity that is peculiar to late-capitalism. This article, drawing upon ongoing ethnographic research among what we term ‘lifestyle gamblers’, utilises a deviant leisure perspective to problematise the myriad harms that emerge from this relationship, situated within a broader critique of consumerism and global capitalism. While social gambling is defended fiercely by the industry, this article argues that an identity-based culture of sports-betting that attaches fragile social and cultural capital to the allure of the gambling win encourages the chasing of losses and impulsive betting. Underscored by a culture of readily available and high-interest credit, we explore how gamblers in a technologically accelerated culture develop a pathological relationship to money as it becomes desublimated and loses its symbolic value. Such processes, exacerbated by the promise of consumer culture, have the potential to cast these young adults into a paralysing reality of indebtedness that is fraught with depression, stress, domestic instability and destructive behaviours of consumption

Vegetation cover and long-term conservation of radioactive waste packages : the case study of the CSM waste disposal facility (Manche district, France)

The CSM is the first French waste disposal facility for radioactive waste. Waste material is buried several meters deep and protected by a multi-layer cover, and equipped with a drainage system. On the surface, the plant cover is a grassland vegetation type. A scientific assessment has been carried out by the G,ophen laboratory, University of Caen, in order to better characterize the plant cover (ecological groups and associated soils) and to observe its medium and long term evolution. Field assessments made on 10 plots were complemented by laboratory analyses carried out over a period of 1 year. The results indicate scenarios and alternative solutions which could arise, in order to passively ensure the long-term safety of the waste disposal system. Several proposals for a blanket solution are currently being studied and discussed, under the auspices of international research institutions in order to determine the most appropriate materials for the storage conditions. One proposal is an increased thickness of these materials associated with a geotechnical barrier since it is well adapted to the forest plants which are likely to colonize the site. The current experiments that are carried out will allow to select the best option and could provide feedback for other waste disposal facility sites already being operated in France (CSFMA waste disposal facility, Aube district) or in other countries