1,279 research outputs found
Value and small firm premiums in the South African market
Numerous studies have identified both value and size effects existing in international markets. Fewer studies have been conducted that document the same effects in the South African market. In this study, portfolios were constructed based on four valuation multiples, as well as market capitalisation from 1999 2012. In this 14-year period it was found that value stocks predominantly outperformed growth stocks when defined by P/E or P/CF. Growth stocks outperformed value stocks when the portfolios were based on P/B and DY. Also, significant evidence of a small firm premium was identified on the JSE, regardless of the valuation multiple. Furthermore, small-cap value stocks generated the highest mean returns over the period. The study identifies the prevalence of these premiums on the JSE, but the comprehensive explanations for these anomalies remain inconclusive
Political and Media Discourses about Integrating Refugees in the UK
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.This article addresses political and media discourses about integrating refugees in the UK in the context of the “refugee crisis”. A discursive psychological approach is presented as the best way to understand what talk about the concept is used to accomplish in these debates. A large corpus of political discussions (13 hours of debate featuring 146 politicians) and 960 newspaper articles from the UK were discourse analysed. The analysis identified five dilemmas about integration: Integration is positive and necessary, but challenging; Host communities are presented as welcoming, but there are limits to their capacity; Refugees are responsible for integration, but host communities need to provide support; Good refugees integrate, bad ones don't; Refugees are vulnerable and are skilled. All are used to warrant the inclusion or exclusion of refugees. The responsibility of western nations to support refugees is therefore contingent on the refugees behaving in specific ways
Diffuse transport and spin accumulation in a Rashba two-dimensional electron gas
The Rashba Hamiltonian describes the splitting of the conduction band as a
result of spin-orbit coupling in the presence of an asymmetric confinement
potential and is commonly used to model the electronic structure of confined
narrow-gap semiconductors. Due to the mixing of spin states some care has to be
exercised in the calculation of transport properties. We derive the diffusive
conductance tensor for a disordered two-dimensional electron gas with
spin-orbit interaction and show that the applied bias induces a spin
accumulation, but that the electric current is not spin-polarized.Comment: REVTeX4 format, 5 page
Value and small firm premiums in the South African market
Numerous studies have identified both value and size effects existing in international markets. Fewer studies have been conducted that document the same effects in the South African market. In this study, portfolios were constructed based on four valuation multiples, as well as market capitalisation from 1999 2012. In this 14-year period it was found that value stocks predominantly outperformed growth stocks when defined by P/E or P/CF. Growth stocks outperformed value stocks when the portfolios were based on P/B and DY. Also, significant evidence of a small firm premium was identified on the JSE, regardless of the valuation multiple. Furthermore, small-cap value stocks generated the highest mean returns over the period. The study identifies the prevalence of these premiums on the JSE, but the comprehensive explanations for these anomalies remain inconclusive
Revisiting the Problem of Searching on a Line
We revisit the problem of searching for a target at an unknown location on a
line when given upper and lower bounds on the distance D that separates the
initial position of the searcher from the target. Prior to this work, only
asymptotic bounds were known for the optimal competitive ratio achievable by
any search strategy in the worst case. We present the first tight bounds on the
exact optimal competitive ratio achievable, parameterized in terms of the given
bounds on D, along with an optimal search strategy that achieves this
competitive ratio. We prove that this optimal strategy is unique. We
characterize the conditions under which an optimal strategy can be computed
exactly and, when it cannot, we explain how numerical methods can be used
efficiently. In addition, we answer several related open questions, including
the maximal reach problem, and we discuss how to generalize these results to m
rays, for any m >= 2
Ballistic spin-polarized transport and Rashba spin precession in semiconductor nanowires
We present numerical calculations of the ballistic spin-transport properties
of quasi-one-dimensional wires in the presence of the spin-orbit (Rashba)
interaction. A tight-binding analog of the Rashba Hamiltonian which models the
Rashba effect is used. By varying the robustness of the Rashba coupling and the
width of the wire, weak and strong coupling regimes are identified. Perfect
electron spin-modulation is found for the former regime, regardless of the
incident Fermi energy and mode number. In the latter however, the
spin-conductance has a strong energy dependence due to a nontrivial subband
intermixing induced by the strong Rashba coupling. This would imply a strong
suppression of the spin-modulation at higher temperatures and source-drain
voltages. The results may be of relevance for the implementation of
quasi-one-dimensional spin transistor devices.Comment: 19 pages (incl. 9 figures). To be published in PR
Spin-polarized transport in inhomogeneous magnetic semiconductors: theory of magnetic/nonmagnetic p-n junctions
A theory of spin-polarized transport in inhomogeneous magnetic semiconductors
is developed and applied to magnetic/nonmagnetic p-n junctions. Several
phenomena with possible spintronic applications are predicted, including
spinvoltaic effect, spin valve effect, and giant magnetoresistance. It is
demonstrated that only nonequilibrium spin can be injected across the
space-charge region of a p-n junction, so that there is no spin injection (or
extraction) at low bias.Comment: Minor Revisions. To appear in Phys. Rev. Let
RPA(D) and HRPA(D): <sup>13</sup>C-<sup>13</sup>C Spin-Spin Coupling Constants for Saturated Cycloalkanes
Spin gap in the Quasi-One-Dimensional S=1/2 Antiferromagnet: Cu2(1,4-diazacycloheptane)2Cl4
Cu_{2}(1,4-diazacycloheptane)_{2}Cl_{4} contains double chains of spin 1/2
Cu^{2+} ions. We report ac susceptibility, specific heat, and inelastic neutron
scattering measurements on this material. The magnetic susceptibility,
, shows a rounded maximum at T = 8 K indicative of a low dimensional
antiferromagnet with no zero field magnetic phase transition. We compare the
data to exact diagonalization results for various one dimensional
spin Hamiltonians and find excellent agreement for a spin ladder with
intra-rung coupling meV and two mutually frustrating
inter-rung interactions: meV and meV. The
specific heat in zero field is exponentially activated with an activation
energy meV. A spin gap is also found through inelastic
neutron scattering on powder samples which identify a band of magnetic
excitations for meV. Using sum-rules we derive an
expression for the dynamic spin correlation function associated with
non-interacting propagating triplets in a spin ladder. The van-Hove
singularities of such a model are not observed in our scattering data
indicating that magnetic excitations in Cu_{2}(1,4-diazacycloheptane)_{2}Cl_{4}
are more complicated. For magnetic fields above T specific
heat data versus temperature show anomalies indicating a phase transition to an
ordered state below T = 1 K.Comment: 9 pages, 8 postscript figures, LaTeX, Submitted to PRB 8/4/97, e-mail
Comments to [email protected]
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