123 research outputs found
THE CHAPLAIN-GENERAL
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 SiOâ films on Si(100) substrates
Cu-implanted SiOâ films on Si(100) have been studied and compared to unimplanted SiOâ 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 SiOââSi(100) and for Cu-implanted and annealedSiOââSi(100). In the latter case, transmission electron microscopy reveals the presence of spherical nanocrystallites with an average size of âŒ2.5ânm. Rutherford backscattering shows that these crystallites (and the Cu in the as-implanted film) are largely confined to depths of 0.4â1.2âÎŒm 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 âŒ7% lower (âŒ2% higher) than for unimplanted SiOââSi(100). Elastic constants were estimated from the acoustic wave velocities and film densities. Cââ (Cââ) for the implanted films was âŒ10% 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 SiOâ 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
A histomorphological analysis of human and non-human femora
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
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
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#FeesMustFall2016: Perceived and measured effect on clinical medical students
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
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
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
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
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