Investigating risk and protective factors to mainstream safety and peace at the University of South Africa

Given the high fatality rates resulting from both unintentional and intentional injuries in South Africa, the identification and prevention of risk factors resulting in injurious incidents as well as the promotion of  protective factors is central to the country’s research agenda. While social science and public health enquiries apply these objectives to various South African contexts, few studies investigate manifest risk and protective factors within South African universities. Accordingly, this study aims to develop the first record of both risk and protective factors at the University of South Africa (Unisa) Muckleneuk Campus as a means to inform future theoretical and practical initiatives in the area. Data was collected with photo-documentaries, unobtrusive field observations, and a peace and safety checklist. The collated data was subjected to a thematic content analysis, allowing for the emergence of four distinct peace and safety promotion themes. These themes include crime, fire injury and electrocution, road and traffic injury, in addition to unintentional injuries. These four themes are discussed, and recommendations are provided, with the intention of informing injury prevention and safety promotion initiatives at the level of both theory and practice in South African tertiary education contexts. This study provides a platform upon which further work in the field can be produced to ensure the safety of students attending tertiary education institutions in South Africa.Keywords: campus safety; crime; traffic; electrocution; injury; South Africa; Unis

Current-voltage characteristics of quasi-one-dimensional superconductors: An S-curve in the constant voltage regime

Applying a constant voltage to superconducting nanowires we find that its IV-characteristic exhibits an unusual S-behavior. This behavior is the direct consequence of the dynamics of the superconducting condensate and of the existence of two different critical currents: j_{c2} at which the pure superconducting state becomes unstable and j_{c1}<j_{c2} at which the phase slip state is realized in the system.Comment: 4 pages, 5 figures, replaced with minor change

Generalizing the DGLAP Evolution of Fragmentation Functions to the Smallest x Values

An approach which unifies the Double Logarithmic Approximation at small x and the leading order DGLAP evolution of fragmentation functions at large x is presented. This approach reproduces exactly the Modified Leading Logarithm Approximation, but is more complete due to the degrees of freedom given to the quark sector and the inclusion of the fixed order terms. We find that data from the largest x values to the peak region can be better fitted than with other approaches.Comment: 10 pages, 3 figure

Information Content in B→VVB \to VV Decays and the Angular Moments Method

The time-dependent angular distributions of decays of neutral $B$ mesons into two vector mesons contain information about the lifetimes, mass differences, strong and weak phases, form factors, and CP violating quantities. A statistical analysis of the information content is performed by giving the ``information'' a quantitative meaning. It is shown that for some parameters of interest, the information content in time and angular measurements combined may be orders of magnitude more than the information from time measurements alone and hence the angular measurements are highly recommended. The method of angular moments is compared with the (maximum) likelihood method to find that it works almost as well in the region of interest for the one-angle distribution. For the complete three-angle distribution, an estimate of possible statistical errors expected on the observables of interest is obtained. It indicates that the three-angle distribution, unraveled by the method of angular moments, would be able to nail down many quantities of interest and will help in pointing unambiguously to new physics.Comment: LaTeX, 34 pages with 9 figure

Photon rockets and gravitational radiation

The absence of gravitational radiation in Kinnersley's ``photon rocket'' solution of Einstein's equations is clarified by studying the mathematically well-defined problem of point-like photon rockets in Minkowski space (i.e. massive particles emitting null fluid anisotro\-pically and accelerating because of the recoil). We explicitly compute the (uniquely defined) {\it linearized} retarded gravitational waves emitted by such objects, which are the coherent superposition of the gravitational waves generated by the motion of the massive point-like rocket and of those generated by the energy-momentum distribution of the photon fluid. In the special case (corresponding to Kinnersley's solution) where the anisotropy of the photon emission is purely dipolar we find that the gravitational wave amplitude generated by the energy-momentum of the photons exactly cancels the usual $1/r$ gravitational wave amplitude generated by the accelerated motion of the rocket. More general photon anisotropies would, however, generate genuine gravitational radiation at infinity. Our explicit calculations show the compatibility between the non-radiative character of Kinnersley's solution and the currently used gravitational wave generation formalisms based on post-Minkowskian perturbation theory.Comment: 21 pages, LATEX, submitted to Class. Quant. Gra

Influence of Vertical Ground Motions on the Seismic Fragility Modeling of a Bridge-Soil-Foundation System

This paper explores the effects of vertical ground motions (VGMs) on the component fragility of a coupled bridged-soil-foundation (CBSF) system with liquefaction potential, and highlights the unique considerations on the demand and capacity model required for fragility analysis under VGMs. Optimal intensity measures (IMs) that account for VGMs are identified. Moreover, fragility curves that consider capacity change with fluctuating axial force are derived. Results show that the presence of VGMs has a minor effect on the failure probabilities of piles and expansion bearings, while it has a great influence on fixed bearings. Whether VGMs have an impact on column fragilities depends on the design axial load ratio. Finally, more accurate fragility surfaces are derived, which are compared with results of conventional fragility curves. This study highlights the important role that VGMs play in the selection of optimal IMs, and the capacity and fragility representation of certain components of CBSF systems

The effect of magnetic field and disorders on the electronic transport in graphene nanoribbons

We developed a unified mesoscopic transport model for graphene nanoribbons, which combines the non-equilibrium Green's function (NEGF) formalism with the real-space {\pi}-orbital model. Based on this model, we probe the spatial distributions of electrons under a magnetic field, in order to obtain insights into the various signature Hall effects in disordered armchair graphene nanoribbons (AGNR). In the presence of a uniform perpendicular magnetic field (B\perp-field), a perfect AGNR shows three distinct spatial current profiles at equilibrium, depending on its width. Under non-equilibrium conditions (i.e. in the presence of an applied bias), the net electron flow is restricted to the edges and occurs in opposite directions depending on whether the Fermi level lies within the valence or conduction band. For electrons at energy level below the conduction window, the B\perp-field gives rise to local electron flux circulation, although the global flux is zero. Our study also reveals the suppression of electron backscattering as a result of the edge transport which is induced by the B\perp-field. This phenomenon can potentially mitigate the undesired effects of disorders, such as the bulk and edge vacancies, on the transport properties of AGNR. Lastly, we show that the effect of B\perp-field on electronic transport is less significant in the multimode compared to the single mode electron transport.Comment: 21 pages, 4 figure

Using participatory and creative methods to facilitate emancipatory research with people facing multiple disadvantage: a role for health and care professionals

Participatory and creative research methods are a powerful tool for enabling active engagement in the research process of marginalised people. It can be particularly hard for people living with multiple disadvantage, such as disabled people from ethnic minority backgrounds, to access research projects that are relevant to their lived experience. This article argues that creative and participatory methods facilitate the co-researchers’ engagement in the research process, which thus becomes more empowering. Exploring the congruence of these methods with their professional ethos, health and care professionals can use their skills to develop them further. Both theory and practice examples are presented

Cherenkov radiation in a gravitational wave background

A covariant criterion for the Cherenkov radiation emission in the field of a non-linear gravitational wave is considered in the framework of exact integrable models of particle dynamics and electromagnetic wave propagation. It is shown that vacuum interacting with curvature can give rise to Cherenkov radiation. The conically shaped spatial distribution of radiation is derived and its basic properties are discussed.Comment: LaTeX file, no figures, 19 page