Results of expert judgments on the faults and risks with Autosub3 and an analysis of its campaign to Pine Island Bay, Antarctica, 2009

Probabilistic risk assessment is a methodology that can be systematically applied to estimate the risk associated with the design and operation of complex systems. The National Oceanography Centre, Southampton, UK has developed a risk management process tailored to the operation of autonomous underwater vehicles. Central to the application of the risk management process is a probabilistic risk assessment. The risk management process was applied to estimate the risk associated with an Autosub3 science campaign in the Pine Island Glacier, Antarctica, and to support decision making. The campaign was successful. In this paper we present the Autosub3 risk model and we show how this model was used to assess the campaign risk

A disintegrating cosmic string

We present a simple sandwich gravitational wave of the Robinson-Trautman family. This is interpreted as representing a shock wave with a spherical wavefront which propagates into a Minkowski background minus a wedge. (i.e. the background contains a cosmic string.) The deficit angle (the tension) of the string decreases through the gravitational wave, which then ceases. This leaves an expanding spherical region of Minkowski space behind it. The decay of the cosmic string over a finite interval of retarded time may be considered to generate the gravitational wave.Comment: 3 pages, 1 figure, to appear in Class. Quantum Gra

Consistent Quantum Counterfactuals

An analysis using classical stochastic processes is used to construct a consistent system of quantum counterfactual reasoning. When applied to a counterfactual version of Hardy's paradox, it shows that the probabilistic character of quantum reasoning together with the ``one framework'' rule prevents a logical contradiction, and there is no evidence for any mysterious nonlocal influences. Counterfactual reasoning can support a realistic interpretation of standard quantum theory (measurements reveal what is actually there) under appropriate circumstances.Comment: Minor modifications to make it agree with published version. Latex 8 pages, 2 figure

From adolescent to adult gambling: an analysis of longitudinal gambling patterns in South Australia [forthcoming]

Although there are many cross-sectional studies of adolescent gambling, very few longitudinal investigations have been undertaken. As a result, little is known about the individual stability of gambling behaviour and the extent to which behaviour measured during adolescence is related to adult behaviour. In this paper, we report the results of a 4-wave longitudinal investigation of gambling behaviour in a probability sample of 256 young people (50% male, 50% female) who were interviewed in 2005 at the age of 16-18 years and then followed through to the age of 20-21 years. The results indicated that young people showed little stability in their gambling. Relatively few reported gambling on the same individual activities consistently over time. Gambling participation rates increased rapidly as young people made the transition from adolescence to adulthood and then were generally more stable. Gambling at 15-16 years was generally not associated with gambling at age 20-21 years. These results highlight the importance of individual-level analyses when examining gambling patterns over time

Cyberstalking: a new challenge for criminal law

Cyberstalking has recently emerged as a new and growing problem and is an area that will probably receive a higher profile within criminal law as more cases reach court (see Griffiths, 1999; Griffiths, Rogers and Sparrow, 1998; Bojic and McFarlane, 2002a; 2002b). For the purposes of this article we define cyberstalking as the use of information and communications technology (in particular the Internet) in order to harass individuals. Such harassment may include actions such as the transmission of offensive e-mail messages, identity theft and damage to data or equipment. Whilst a more comprehensive definition has been presented elsewhere (Bocij and McFarlane, 2002), it is hoped that the definition here is sufficient for those unfamiliar with this field. The stereotypical stalker conjures up images of someone harassing a victim who is the object of their affection. However, not all stalking incidents are motivated by unrequited love. Stalking can also be motivated by hate, a need for revenge, a need for power and/or racism. Similarly, cyberstalking can involve acts that begin with the issuing of threats and end in physical assault. We also make distinctions between conventional stalking and cyberstalking. Whilst some may view cyberstalking as an extension of conventional stalking, we believe cyberstalking should be regarded as an entirely new form of deviant behaviour

Prevalence of pathological Internet use among university students and correlations with self-esteem, the general health questionnaire (GHQ), and disinhibition

Over the last few years, there has been increased interest in the addictive potential of the Internet. The current study was an attempt to replicate common findings in the literature and provide more evidence for the existence of Internet addiction among students—a population considered to be especially vulnerable. A total of 371 British students responded to the questionnaire, which included the Pathological Internet Use (PIU) scale, the General Health Questionnaire (GHQ-12), a self-esteem scale, and two measures of disinhibition. Results showed that 18.3% of the sample were considered to be pathological Internet users, whose excessive use of the Internet was causing academic, social, and interpersonal problems. Other results showed that pathological Internet users had lower self-esteem and were more socially disinhibited. However, there was no significant difference in GHQ scores. These results are discussed in relation to the methodological shortcomings of research in the area as a whole

The surface-tension-driven evolution of a two-dimensional annular viscous tube

We consider the evolution of an annular two-dimensional region occupied by viscous fluid driven by surface tension and applied pressure at the free surfaces. We assume that the thickness of the domain is small compared with its circumference so that it may be described as a thin viscous sheet whose ends are joined to form a closed loop. Analytical and numerical solutions of the resulting model are obtained and we show that it is well posed whether run forwards or backwards in time. This enables us to determine, in many cases explicitly, which initial shapes will evolve into a desired final shape. We also show how the application of an internal pressure may be used to control the evolution. This work is motivated by the production of non-axisymmetric capillary tubing via the Vello process. Molten glass is fed through a die and drawn off vertically, while the shape of the cross-section evolves under surface tension and any applied pressure as it flows downstream. Here the goal is to determine the die shape required to achieve a given desired final shape, typically square or rectangular. We conclude by discussing the role of our two-dimensional model in describing the three-dimensional tube-drawing process

Mathematical modelling of non-axisymmetric capillary tube drawing

This paper concerns the manufacture of non-axisymmetric capillary tubing via the Velloprocess, in which molten glass is fed through a die and drawn off vertically. The shapeof the cross-section evolves under surface tension as it flows downstream. The aim is to achieve a given desired final shape, typically square or rectangular, and our goal is to determine the required die shape. We use the result that, provided the tube is slowly varying in the axial direction, each cross-section evolves like a two-dimensional Stokes flow when expressed in suitably scaled Lagrangian coordinates. This allows us to use a previously derived model for the surface- tension-driven evolution of a thin two-dimensional viscous tube. We thus obtain, and solve analytically, equations governing the axial velocity, thickness and circumference of the tube, as well as its shape. The model is extended to include non-isothermal effects

Phase diagram for the ν=0\nu=0 quantum Hall state in monolayer graphene

The $\nu=0$ quantum Hall state in a defect-free graphene sample is studied within the framework of quantum Hall ferromagnetism. We perform a systematic analysis of the pseudospin anisotropies, which arise from the valley and sublattice asymmetric short-range electron-electron (e-e) and electron-phonon (e-ph) interactions. The phase diagram, obtained in the presence of generic pseudospin anisotropy and the Zeeman effect, consists of four phases characterized by the following orders: spin-polarized ferromagnetic, canted antiferromagnetic, charge density wave, and Kekul\'{e} distortion. We take into account the Landau level mixing effects and show that they result in the key renormalizations of parameters. First, the absolute values of the anisotropy energies become greatly enhanced and can significantly exceed the Zeeman energy. Second, the signs of the anisotropy energies due to e-e interactions can change upon renormalization. A crucial consequence of the latter is that the short-range e-e interactions alone could favor any state on the phase diagram, depending on the details of interactions at the lattice scale. On the other hand, the leading e-ph interactions always favor the Kekul\'{e} distortion order. The possibility of inducing phase transitions by tilting the magnetic field is discussed.Comment: 25 pages, 19 figs; v2: nearly identical to the published version, some stylistic improvements, Tables I-IV added, anisotropy energies redefined as u -> u/2 for aesthetic reaso