Optimally coherent sets in geophysical flows: A new approach to delimiting the stratospheric polar vortex

The "edge" of the Antarctic polar vortex is known to behave as a barrier to the meridional (poleward) transport of ozone during the austral winter. This chemical isolation of the polar vortex from the middle and low latitudes produces an ozone minimum in the vortex region, intensifying the ozone hole relative to that which would be produced by photochemical processes alone. Observational determination of the vortex edge remains an active field of research. In this letter, we obtain objective estimates of the structure of the polar vortex by introducing a new technique based on transfer operators that aims to find regions with minimal external transport. Applying this new technique to European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-40 three-dimensional velocity data we produce an improved three-dimensional estimate of the vortex location in the upper stratosphere where the vortex is most pronounced. This novel computational approach has wide potential application in detecting and analysing mixing structures in a variety of atmospheric, oceanographic, and general fluid dynamical settings

The weak password problem: chaos, criticality, and encrypted p-CAPTCHAs

Vulnerabilities related to weak passwords are a pressing global economic and security issue. We report a novel, simple, and effective approach to address the weak password problem. Building upon chaotic dynamics, criticality at phase transitions, CAPTCHA recognition, and computational round-off errors we design an algorithm that strengthens security of passwords. The core idea of our method is to split a long and secure password into two components. The first component is memorized by the user. The second component is transformed into a CAPTCHA image and then protected using evolution of a two-dimensional dynamical system close to a phase transition, in such a way that standard brute-force attacks become ineffective. We expect our approach to have wide applications for authentication and encryption technologies.Comment: 5 pages, 6 figer

NPSOFF: An Object Description Language for Supporting Virtual World Construction

Computers & Graphics, Vol. 17, No. 4, pp 457-464, January 25, 1994.Accepted/Published Paper (Refereed

The significance of work allocation in the professional apprenticeship of solicitors

It is a peculiarity of the solicitors’ profession that it has historically relied on methods of pre-qualification ‘training’ by way of apprenticeship and that an entirely respectable non-graduate route into the profession remains. In a political context, however, where the profession is called upon positively to demonstrate its standards of performance, the professional regulator seeks to attach a competence framework to the existing model; shifting the focus from how the trainee learns to what the trainee learns. This paper will explore the period of traineeship from the perspective of the trainees themselves, drawing on two small qualitative studies, focussing on the fundamental context factor of the allocation and structuring of their work. In the first study the context for this evaluation is the set of outcomes being tested by the professional regulator and in the second, the perceptions of qualified individuals looking back at their apprenticeship, The paper concludes that there remains work for the profession to do not only in fostering supportive and expansive apprenticeships, but in attending, however, supportive the surrounding environment, to the work being carried out by trainees and its relationship with the work carried out by newly qualified solicitors

Performativity, fabrication and trust: exploring computer-mediated moderation

Based on research conducted in an English secondary school, this paper explores computer mediated moderation as a performative tool. The Module Assessment Meeting (MAM) was the moderation approach under investigation. I mobilise ethnographic data generated by a key informant, and triangulated with that from other actors in the setting, in order to examine some of the meanings underpinning moderation within a performative environment. Drawing on the work of Ball (2003), Lyotard (1979) and Foucault (1977, 1979), I argue that in this particular case performativity has become entrenched in teachers’ day-to-day practices, and not only affects those practices but also teachers’ sense of self. I suggest that MAM represented performative and fabricated conditions and (re)defined what the key participant experienced as a vital constituent of her educational identities - trust. From examining the case in point, I hope to have illustrated for those interested in teachers’ work some of the implications of the interface between technology and performativity

Comparative Proteomic Analysis of Differentially Expressed Proteins in the Urine of Reservoir Hosts of Leptospirosis

Rattus norvegicus is a natural reservoir host for pathogenic species of Leptospira. Experimentally infected rats remain clinically normal, yet persistently excrete large numbers of leptospires from colonized renal tubules via urine, despite a specific host immune response. Whilst persistent renal colonization and shedding is facilitated in part by differential antigen expression by leptospires to evade host immune responses, there is limited understanding of kidney and urinary proteins expressed by the host that facilitates such biological equilibrium. Urine pellets were collected from experimentally infected rats shedding leptospires and compared to urine from non-infected controls spiked with in vitro cultivated leptospires for analysis by 2-D DIGE. Differentially expressed host proteins include membrane metallo endopeptidase, napsin A aspartic peptidase, vacuolar H+ATPase, kidney aminopeptidase and immunoglobulin G and A. Loa22, a virulence factor of Leptospira, as well as the GroEL, were increased in leptospires excreted in urine compared to in vitro cultivated leptospires. Urinary IgG from infected rats was specific for leptospires. Results confirm differential protein expression by both host and pathogen during chronic disease and include markers of kidney function and immunoglobulin which are potential biomarkers of infection

Mindfulness-based interventions for young offenders: a scoping review

Youth offending is a problem worldwide. Young people in the criminal justice system have frequently experienced adverse childhood circumstances, mental health problems, difficulties regulating emotions and poor quality of life. Mindfulness-based interventions can help people manage problems resulting from these experiences, but their usefulness for youth offending populations is not clear. This review evaluated existing evidence for mindfulness-based interventions among such populations. To be included, each study used an intervention with at least one of the three core components of mindfulness-based stress reduction (breath awareness, body awareness, mindful movement) that was delivered to young people in prison or community rehabilitation programs. No restrictions were placed on methods used. Thirteen studies were included: three randomized controlled trials, one controlled trial, three pre-post study designs, three mixed-methods approaches and three qualitative studies. Pooled numbers (n = 842) comprised 99% males aged between 14 and 23. Interventions varied so it was not possible to identify an optimal approach in terms of content, dose or intensity. Studies found some improvement in various measures of mental health, self-regulation, problematic behaviour, substance use, quality of life and criminal propensity. In those studies measuring mindfulness, changes did not reach statistical significance. Qualitative studies reported participants feeling less stressed, better able to concentrate, manage emotions and behaviour, improved social skills and that the interventions were acceptable. Generally low study quality limits the generalizability of these findings. Greater clarity on intervention components and robust mixed-methods evaluation would improve clarity of reporting and better guide future youth offending prevention programs