1,456 research outputs found
Human trafficking and the exploitation of women and children in a Southern and South African context
Human trafficking in South Africa is a serious problem which needs intervention on all fronts. This article seeks to extend the understanding of the different forms of exploitation which women and children are exposed to in the trafficking chain. The results of the research clearly indicate that South Africa is a source, transit and destination country for trafficked women and children. The study identified a number of trafficking flows in the intercontinental trafficking of women and children to and from South Africa from the rest of the Continent of Africa, as well as domestic trafficking. Trafficking of South Africans out of South Africa was found to be less problematic and only a few cases were reported. The research confirmed that, as it occurs in most countries, women are mainly the victims of human trafficking in South Africa, with the main purpose of sexual exploitation. Young girls are also trafficked for sexual exploitation. Women and children are trafficked into domestic servitude, forced labour or debt bondage. These women are also used in criminal activities like drug smuggling, begging, trafficking for the removal of body parts (or muti) and for sacrifice in rituals
Patch behaviour and predictability properties of modelled finite-amplitude sand ridges on the inner shelf
The long-term evolution of shoreface-connected sand ridges is investigated with a nonlinear spectral model which governs the dynamics of waves, currents, sediment transport and the bed level on the inner shelf. Wave variables are calculated with a shoaling-refraction model instead of using a parameterisation. The spectral model describes the time evolution of amplitudes of known eigenmodes of the linearised system. Bottom pattern formation occurs if the transverse bottom slope of the inner shelf, β, exceeds a critical value &beta;<sub>c</sub>. For fixed model parameters the sensitivity of the properties of modelled sand ridges to changes in the number (<i>N</i>&minus;1) of resolved subharmonics (of the initially fastest growing mode) is investigated. For any <i>N</i> the model shows the growth and subsequent saturation of the height of the sand ridges. The saturation time scale is several thousands of years, which suggests that observed sand ridges have not reached their saturated stage yet. The migration speed of the ridges and the average longshore spacing between successive crests in the saturated state differ from those in the initial state. Analysis of the potential energy balance of the ridges reveals that bed slope-induced sediment transport is crucial for the saturation process. In the transient stage the shoreface-connected ridges occur in patches. The overall characteristics of the bedforms (saturation time, final maximum height, average longshore spacing, migration speed) hardly vary with <i>N</i>. However, individual time series of modal amplitudes and bottom patterns strongly depend on <i>N</i>, thereby implying that the detailed evolution of sand ridges can only be predicted over a limited time interval. Additional experiments show that the critical bed slope &beta;<sub>c</sub> increases with larger offshore angles of wave incidence, larger offshore wave heights and longer wave periods, and that the corresponding maximum height of the ridges decreases whilst the saturation time increases
Robust zero-energy modes in an electronic higher-order topological insulator: the dimerized Kagome lattice
Quantum simulators are an essential tool for understanding complex quantum
materials. Platforms based on ultracold atoms in optical lattices and photonic
devices led the field so far, but electronic quantum simulators are proving to
be equally relevant. Simulating topological states of matter is one of the holy
grails in the field. Here, we experimentally realize a higher-order electronic
topological insulator (HOTI). Specifically, we create a dimerized Kagome
lattice by manipulating carbon-monoxide (CO) molecules on a Cu(111) surface
using a scanning tunneling microscope (STM). We engineer alternating weak and
strong bonds to show that a topological state emerges at the corner of the
non-trivial configuration, while it is absent in the trivial one. Contrarily to
conventional topological insulators (TIs), the topological state has two
dimensions less than the bulk, denoting a HOTI. The corner mode is protected by
a generalized chiral symmetry, which leads to a particular robustness against
perturbations. Our versatile approach to quantum simulation with artificial
lattices holds promises of revealing unexpected quantum phases of matter
Evidence use as sociomaterial practice? A qualitative study of decision-making on introducing service innovations in health care
A policy aspiration is that evidence should inform decision-making on introducing health service innovations. Internationally, innovation adoption has historically been slow and patchy. Three innovations in the English and Scottish National Health Service were analysed qualitatively: stroke service reconfiguration; revised national guidance on cancer referral; and ‘virtual’ glaucoma outpatient clinics. The authors identify three sociomaterial mechanisms through which evidence and context shape each other in decision-making: connecting, ordering, resisting. Shared preferences for research evidence enabled the medical profession to exert influence on decision-making, while other professions used alternative evidence. Implications for promoting inclusive public management around service innovations are discussed
SU(3) Decomposition of Two-Body B Decay Amplitudes
We present the complete flavor SU(3) decomposition of decay amplitudes for
decays of the triplet (B^+_u, B^0_d, B^0_s) of B mesons nonleptonically into
two pseudoscalar mesons. This analysis holds for arbitrarily broken SU(3) and
can be used to generate amplitude relations when physical arguments permit one
to neglect or relate any of the reduced amplitudes.Comment: 31 pages, revtex, no figure
Chiral effective theory predictions for deuteron form factor ratios at low Q^2
We use chiral effective theory to predict the deuteron form factor ratio
G_C/G_Q as well as ratios of deuteron to nucleon form factors. These ratios are
calculated to next-to-next-to-leading order. At this order the chiral expansion
for the NN isoscalar charge operator (including consistently calculated 1/M
corrections) is a parameter-free prediction of the effective theory. Use of
this operator in conjunction with NLO and NNLO chiral effective theory wave
functions produces results that are consistent with extant experimental data
for Q^2 < 0.35 GeV^2. These wave functions predict a deuteron quadrupole moment
G_Q(Q^2=0)=0.278-0.282 fm^2-with the variation arising from short-distance
contributions to this quantity. The variation is of the same size as the
discrepancy between the theoretical result and the experimental value. This
motivates the renormalization of G_Q via a two-nucleon operator that couples to
quadrupole photons. After that renormalization we obtain a robust prediction
for the shape of G_C/G_Q at Q^2 < 0.3 GeV^2. This allows us to make precise,
model-independent predictions for the values of this ratio that will be
measured at the lower end of the kinematic range explored at BLAST. We also
present results for the ratio G_C/G_M.Comment: 31 pages, 7 figure
Dynamic polarization effects on the angular distributions of protons channeled through carbon nanotubes in dielectric media
The best level of ordering and straightening of carbon nanotube arrays is
often achieved when they are grown in a dielectric matrix, so such structures
present the most suitable candidates for future channeling experiments with
carbon nanotubes. Consequently, we investigate here how the dynamic
polarization of carbon valence electrons in the presence of various surrounding
dielectric media affects the angular distributions of protons channeled through
(11,~9) single-wall carbon nanotubes. Proton speeds between 3 and 10 a.u.,
corresponding to energies of 0.223 and 2.49 MeV, are chosen with the nanotube's
length varied between 0.1 and 1 m. We describe the repulsive interaction
between a proton and the nanotube's atoms in a continuum-potential
approximation based on the Doyle-Turner potential, whereas the attractive image
force on a proton is calculated using a two-dimensional hydrodynamic model for
the dynamic response of the nanotube valence electrons, while assigning to the
surrounding medium an appropriate (frequency dependent) dielectric function.
The angular distributions of channeled protons are generated using a computer
simulation method which solves the proton equations of motion in the transverse
plane numerically. Our analysis shows that the presence of a dielectric medium
can strongly affect both the appearance and positions of maxima in the angular
distributions of channeled protons.Comment: 14 pages, 11 figures, Accepted for publication in Phys. Rev.
Evaluating Local Community Methods in Networks
We present a new benchmarking procedure that is unambiguous and specific to
local community-finding methods, allowing one to compare the accuracy of
various methods. We apply this to new and existing algorithms. A simple class
of synthetic benchmark networks is also developed, capable of testing
properties specific to these local methods.Comment: 8 pages, 9 figures, code included with sourc
Bounds on the Complexity of Halfspace Intersections when the Bounded Faces have Small Dimension
We study the combinatorial complexity of D-dimensional polyhedra defined as
the intersection of n halfspaces, with the property that the highest dimension
of any bounded face is much smaller than D. We show that, if d is the maximum
dimension of a bounded face, then the number of vertices of the polyhedron is
O(n^d) and the total number of bounded faces of the polyhedron is O(n^d^2). For
inputs in general position the number of bounded faces is O(n^d). For any fixed
d, we show how to compute the set of all vertices, how to determine the maximum
dimension of a bounded face of the polyhedron, and how to compute the set of
bounded faces in polynomial time, by solving a polynomial number of linear
programs
The Lambda-Lambda Interaction and ^{6}_{Lambda Lambda}He
An OBE potential model for the ^{1}S_0 S = -2 interaction is analyzed with
emphasis on the role of coupling between the Lambda Lambda, N Xi, and Sigma
Sigma channels. Singlet scalar exchange, an approximation to two-pion exchange,
is significant in all channels; surprisingly, the one-pion exchange component
is almost negligible. The size of the channel coupling as a function of the
overall strength of the OBE model potential is examined. Implications of the
analysis for the binding energy of ^{6}_{Lambda Lambda}He are considered; the
new experimental datum may suggest a consistency between the extracted Lambda
Lambda matrix element and the relation implied by SU(3) among OBE baryon-baryon
interactions. \\Comment: 4 pages brief report to Physical Review
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