123 research outputs found

    THE CHAPLAIN-GENERAL

    Get PDF
    The adoption of the Union Defence Act No 13 of 1912 led to the creation of the Union Defence Force. In this regard article 28 Sub-article 5 of the Act also made provision for the appointment of military chaplains: 'Citizens may be appointed to commissioned rank as Chaplains .. .'1

    Structural and elastic characterization of Cu-implanted SiO₂ films on Si(100) substrates

    Get PDF
    Cu-implanted SiO₂ films on Si(100) have been studied and compared to unimplanted SiO₂ on Si(100) using x-ray methods, transmission electron microscopy, Rutherford backscattering, and Brillouin spectroscopy. The x-ray results indicate the preferred orientation of Cu {111} planes parallel to the Si substrate surface without any directional orientation for Cu-implanted SiO₂∕Si(100) and for Cu-implanted and annealedSiO₂∕Si(100). In the latter case, transmission electron microscopy reveals the presence of spherical nanocrystallites with an average size of ∌2.5 nm. Rutherford backscattering shows that these crystallites (and the Cu in the as-implanted film) are largely confined to depths of 0.4−1.2 Όm below the film surface. Brillouin spectra contain peaks due to surface, film-guided and bulk acoustic modes. Surface (longitudinal) acoustic wave velocities for the implanted films were ∌7% lower (∌2% higher) than for unimplanted SiO₂∕Si(100). Elastic constants were estimated from the acoustic wave velocities and film densities. C₁₁ (C₄₄) for the implanted films was ∌10% higher (lower) than that for the unimplanted film. The differences in acoustic velocities and elastic moduli are ascribed to implantation-induced compaction and/or the presence of Cu in the SiO₂ film.B.J. and M.C.R. are grateful for financial support from the Australian Synchrotron Research Program, funded by the Commonwealth of Australia. M.C.R. would also like to thank the Australian Research Council for their financial support. The financial support of the Natural Sciences and Engineering Research Council of Canada NSERC is gratefully acknowledged by G.T.A. and J.S

    Rank and the Drazin inverse in Banach algebras

    Full text link

    A histomorphological analysis of human and non-human femora

    Get PDF
    Histology is used to describe post-mortem bone alterations, trauma, pathology, age estimation and to separate human and nonhuman bones. Many scholars are however not familiar with the intricate and variable microstructure of bone and due to the complex nature of some classification systems, bone histomorphology is often incorrectly described or identified. Little information is available on the histomorphology of nonhuman bones found in southern Africa and therefore the aim of this study was to describe the histomorphology of nonhuman species commonly found in southern Africa, namely, impala and monkeys, along with cat, dog, cow, sheep, equid and pig. Human femora were included for comparative purposes. The periosteal surface of femora was described and focused only on the arrangements of vascular canals, primary osteons and secondary osteons. The results compared favourably to other studies and also added a histomorphological description of impala femora which consisted of primary vascular longitudinal bone tissue. A large degree of overlap and combinations of bone tissue types was observed as well as evidence that allow animals from similar taxonomic orders to be grouped together. Primary vascular bone was primarily observed in artiodactyls (cow, pig, sheep and impala), while Haversian bone was recognised in carnivores (cat and dog), perissodactyla (horses and donkeys) and primates. These differences can be used to exclude human from unknown bone fragments and also serve to caution investigators when using animal models to infer human bone tissue responses to thermal damage, ballistic trauma, etc., as bone tissue types different to that of human bone may respond differently.Navkom and National Research Foundation (NRF)http://link.springer.com/journal/414hb201

    Horizon energy and angular momentum from a Hamiltonian perspective

    Full text link
    Classical black holes and event horizons are highly non-local objects, defined in terms of the causal past of future null infinity. Alternative, (quasi)local definitions are often used in mathematical, quantum, and numerical relativity. These include apparent, trapping, isolated, and dynamical horizons, all of which are closely associated to two-surfaces of zero outward null expansion. In this paper we show that three-surfaces which can be foliated with such two-surfaces are suitable boundaries in both a quasilocal action and a phase space formulation of general relativity. The resulting formalism provides expressions for the quasilocal energy and angular momentum associated with the horizon. The values of the energy and angular momentum are in agreement with those derived from the isolated and dynamical horizon frameworks.Comment: 39 pages, 3 figures, Final Version : content essentially unchanged but many small improvements made in response to referees, a few references adde

    #FeesMustFall2016: Perceived and measured effect on clinical medical students

    Get PDF
    Background. Medical students are under immense academic stress. Campus unrest can contribute to stress and influence academic performance, social behaviour, emotional stability and financial expenses.Objectives. To investigate the effects of #FeesMustFall2016 (#FMF2016) on the 2016 3rd-year (semester 6) clinical medical students at the University of the Free State (UFS), Bloemfontein, South Africa.Methods. In phase 1 of the project, anonymous questionnaires were completed by the clinical students who experienced physical test disruption during #FMF2016. Opinions regarding academic performance, financial expenses, behaviour changes and stress levels were gathered. The students also completed a formal post-traumatic stress screening assessment. In phase 2 of the project, the academic performance of these students was compared with that of students not affected by #FMF2016.Results. Of the target population of 138 students, 87.0% completed the questionnaires. Three-quarters of the respondents reported a negative effect on academic performance, and most did not believe that the delivering of lectures on Blackboard was a good way of training. Alcohol consumption increased in 31.9% of the students. Criteria for post-traumatic stress disorder (PTSD) were met in 12.7% of students. Compared with previous and later cohorts of students there were no clear differences regarding marks, but there was a tendency towards poorer performance and more failures the next year.Conclusions. Semester 6 medical students at UFS reported that the #FMF2016 protests had a negative effect on academic, social, financial and stress aspects. PTSD was present in 12.7% of students compared with 7.8% in similar populations.

    Nonperturbative renormalization group approach to frustrated magnets

    Full text link
    This article is devoted to the study of the critical properties of classical XY and Heisenberg frustrated magnets in three dimensions. We first analyze the experimental and numerical situations. We show that the unusual behaviors encountered in these systems, typically nonuniversal scaling, are hardly compatible with the hypothesis of a second order phase transition. We then review the various perturbative and early nonperturbative approaches used to investigate these systems. We argue that none of them provides a completely satisfactory description of the three-dimensional critical behavior. We then recall the principles of the nonperturbative approach - the effective average action method - that we have used to investigate the physics of frustrated magnets. First, we recall the treatment of the unfrustrated - O(N) - case with this method. This allows to introduce its technical aspects. Then, we show how this method unables to clarify most of the problems encountered in the previous theoretical descriptions of frustrated magnets. Firstly, we get an explanation of the long-standing mismatch between different perturbative approaches which consists in a nonperturbative mechanism of annihilation of fixed points between two and three dimensions. Secondly, we get a coherent picture of the physics of frustrated magnets in qualitative and (semi-) quantitative agreement with the numerical and experimental results. The central feature that emerges from our approach is the existence of scaling behaviors without fixed or pseudo-fixed point and that relies on a slowing-down of the renormalization group flow in a whole region in the coupling constants space. This phenomenon allows to explain the occurence of generic weak first order behaviors and to understand the absence of universality in the critical behavior of frustrated magnets.Comment: 58 pages, 15 PS figure

    The Chiral MagnetoHydroDynamics of QCD fluid at RHIC and LHC

    Full text link
    The experimental results on heavy ion collisions at RHIC and LHC indicate that QCD plasma behaves as a nearly perfect fluid described by relativistic hydrodynamics. Hydrodynamics is an effective low-energy Theory Of Everything stating that the response of a system to external perturbations is dictated by conservation laws that are a consequence of the symmetries of the underlying theory. In the case of QCD fluid produced in heavy ion collisions, this theory possesses anomalies, so some of the apparent classical symmetries are broken by quantum effects. Even though the anomalies appear as a result of UV regularization and so look like a short distance phenomenon, it has been realized recently that they also affect the large distance, macroscopic behavior in hydrodynamics. One of the manifestations of anomalies in relativistic hydrodynamics is the Chiral Magnetic Effect (CME). At this conference, a number of evidences for CME have been presented, including i) the disappearance of charge asymmetry fluctuations in the low-energy RHIC data where the energy density is thought to be below the critical one for deconfinement; ii) the observation of charge asymmetry fluctuations in Pb-Pb collisions at the LHC. Here I give a three-page summary of some of the recent theoretical and experimental developments and of the future tests that may allow to establish (or to refute) the CME as the origin of the observed charge asymmetry fluctuations.Comment: 4 pages, talk at Quark Matter 2011 Conference, Annecy, France, 23-28 May 201

    Holographic Gravitational Anomaly and Chiral Vortical Effect

    Full text link
    We analyze a holographic model with a pure gauge and a mixed gauge-gravitational Chern-Simons term in the action. These are the holographic implementations of the usual chiral and the mixed gauge-gravitational anomalies in four dimensional field theories with chiral fermions. We discuss the holographic renormalization and show that the gauge-gravitational Chern-Simons term does not induce new divergences. In order to cancel contributions from the extrinsic curvature at a boundary at finite distance a new type of counterterm has to be added however. This counterterm can also serve to make the Dirichlet problem well defined in case the gauge field strength vanishes on the boundary. A charged asymptotically AdS black hole is a solution to the theory and as an application we compute the chiral magnetic and chiral vortical conductivities via Kubo formulas. We find that the characteristic term proportional to T^2 is present also at strong coupling and that its numerical value is not renormalized compared to the weak coupling result.Comment: 27 pages, no figure
    • 

    corecore