2,917 research outputs found

    Are some fund managers better than others? Manager characteristics and fund performance

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    CITATION: Friis, L. B. & Smit, E. v d M. 2004. Are some fund managers better than others? Manager characteristics and fund performance. South African Journal of Business Management, 35(3):a660, doi:10.4102/sajbm.v35i3.660.The original publication is available at https://sajbm.orgThe research objective has been to find out whether fund manager characteristics help explain fund performance and propensity to risk taking. Eight independent variables; manager age, tenure of the manager with the fund, years of education, whether the manager holds a MBA or CA/CFA qualification, management team size, fund age and fund objective are regressed on measures of fund performance and riskiness. The findings of the study are highly significant and show that fund performance and riskiness are impacted upon by managers’ qualifications. One can expect better risk-adjusted performance from a fund manager who holds a CA/CFA qualification. Results show that these managers outperform managers without these qualifications, while taking on less risk than managers with MBA qualifications.https://sajbm.org/index.php/sajbm/article/view/660Publisher's versio

    Screening of the topological charge in a correlated instanton vacuum

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    Screening of the topological charge due to he fermion-induced interactions is an important phenomenon, closely related with the resolution of the strong CP and U(1) problems. We study the mechanism of such screening in a 'correlated instanton vacuum', as opposed to the 'random' one. Both scalar and pseudoscalar gluonic correlators are analyzed by means of an observable that minimizes finite size effects. Screening of the topological charge is established. This allows us to calculate the η\eta' mass without having to invert the Dirac operator. We suggest that this method might be used in lattice QCD calculations as well. Our results for the screening of the topological charge are in agreement with the chiral Ward identities, and the scalar gluonic correlator satisfies a low energy theorem first derived by Novikov et al. \cite{Novikov-etal}. We also propose to evaluate the topological susceptibility in the Witten-Veneziano formula not in an infinite box in an world withoutwithout fermions but in an infinitesimal box in a world withwith fermions.Comment: 22 pages + 5 postscript figures, SUNY-NTG/94-25. Corrected LATEX erro

    Gas exchange during storage and incubation of Avian eggs: Effects on embryogenesis, hatchability, chick quality and post-hatch growth

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    Embryonic development is a dynamic process that requires a fine balance between several factors in order to achieve an optimum hatchability and chick quality. These factors include the background of the embryo, such as genetic line of the breeders, the age of the breeder, egg weight, and factors related to the environment in which the egg is stored and incubated, such as temperature, humidity, gas levels and altitude. Gas exchanges are of fundamental importance for embryonic development during incubation and may affect the livability of the embryo. This paper reviews the roles of the gaseous environment (i.e. O 2 and CO2) around hatching eggs during storage and during incubation and the effect it might have on the survival of the developing embryos and the chicks that hatch. The state of the art on the different attempts to establish the optimum requirements of different gases that promote the optimal developmental trajectories at different periods during incubation is presented. The roles and consequences of different levels of O2 and CO2 during storage and incubation on hatchability, incubation duration, hatching process, embryo growth, embryo mortality, organ development and morphology, metabolism, blood acid-base balance, chick quality and chick post-hatch growth are reviewed. © 2007 World's Poultry Science Association

    Investigation of the Domain Wall Fermion Approach to Chiral Gauge Theories on the Lattice

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    We investigate a recent proposal to construct chiral gauge theories on the lattice using domain wall fermions. We restrict ourselves to the finite volume case, in which two domain walls are present, with modes of opposite chirality on each of them. We couple the chiral fermions on only one of the domain walls to a gauge field. In order to preserve gauge invariance, we have to add a scalar field, which gives rise to additional light mirror fermion and scalar modes. We argue that in an anomaly free model these extra modes would decouple if our model possesses a so-called strong coupling symmetric phase. However, our numerical results indicate that such a phase most probably does not exist. ---- Note: 9 Postscript figures are appended as uuencoded compressed tar file.Comment: 27p. Latex; UCSD/PTH 93-28, Wash. U. HEP/93-6

    Isotopic Production Cross Sections in Proton-Nucleus Collisions at 200 MeV

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    Intermediate mass fragments (IMF) from the interaction of 27^{27}Al, 59^{59}Co and 197^{197}Au with 200 MeV protons were measured in an angular range from 20 degree to 120 degree in the laboratory system. The fragments, ranging from isotopes of helium up to isotopes of carbon, were isotopically resolved. Double differential cross sections, energy differential cross sections and total cross sections were extracted.Comment: accepted by Phys. Rev.

    Phase Coexistence of a Stockmayer Fluid in an Applied Field

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    We examine two aspects of Stockmayer fluids which consists of point dipoles that additionally interact via an attractive Lennard-Jones potential. We perform Monte Carlo simulations to examine the effect of an applied field on the liquid-gas phase coexistence and show that a magnetic fluid phase does exist in the absence of an applied field. As part of the search for the magnetic fluid phase, we perform Gibbs ensemble simulations to determine phase coexistence curves at large dipole moments, μ\mu. The critical temperature is found to depend linearly on μ2\mu^2 for intermediate values of μ\mu beyond the initial nonlinear behavior near μ=0\mu=0 and less than the μ\mu where no liquid-gas phase coexistence has been found. For phase coexistence in an applied field, the critical temperatures as a function of the applied field for two different μ\mu are mapped onto a single curve. The critical densities hardly change as a function of applied field. We also verify that in an applied field the liquid droplets within the two phase coexistence region become elongated in the direction of the field.Comment: 23 pages, ReVTeX, 7 figure

    An empirical framework of control methods of victims of human trafficking for sexual exploitation

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    Although human trafficking for sexual exploitation is a frequently discussed area in current research, especially on the way that human traffickers control their victims, a recurrent problem is the lack of empirical basis. The present study examines control methods (or conditions) used against 137 victims of human trafficking for sexual exploitation. A multidimensional scaling analysis (smallest space analysis (SSA-I)) of 23 control methods (and conditions) derived from a content analysis of police files from the Netherlands revealed three distinct forms of control. These could be interpreted in terms of Canter’s Victim Role model that has been the basis for differentiating offending styles in other violent interpersonal offences. Further analysis showed a relationship between these control styles and different types of prostitution. The three Victim as Object, Victim as Vehicle and Victim as Person modes are consistent with different control methods identified in previous research

    Spontaneous symmetry breaking in strong-coupling lattice QCD at high density

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    We determine the patterns of spontaneous symmetry breaking in strong-coupling lattice QCD in a fixed background baryon density. We employ a next-nearest-neighbor fermion formulation that possesses the SU(N_f)xSU(N_f) chiral symmetry of the continuum theory. We find that the global symmetry of the ground state varies with N_f and with the background baryon density. In all cases the condensate breaks the discrete rotational symmetry of the lattice as well as part of the chiral symmetry group.Comment: 10 pages, RevTeX 4; added discussion of accidental degeneracy of vacuum after Eq. (35

    Studies of the Giant Dipole Resonance in 27^{27}Al, 40^{40}Ca, 56^{56}Fe, 58^{58}Ni and 208^{208}Pb with high energy-resolution inelastic proton scattering under 0^\circ

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    A survey of the fine structure of the Isovector Giant Dipole Resonance (IVGDR) was performed, using the recently commissioned zero-degree facility of the K600 magnetic spectrometer at iThemba LABS. Inelastic proton scattering at an incident energy of 200 MeV was measured on 27^{27}Al, 40^{40}Ca, 56^{56}Fe, 58^{58}Ni and 208^{208}Pb. A high energy resolution (ΔE\rm{\Delta}\it{E} \simeq 40 keV FWHM) could be achieved after utilising faint-beam and dispersion-matching techniques. Considerable fine structure is observed in the energy region of the IVGDR and characteristic energy scales are extracted from the experimental data by means of a wavelet analysis. The comparison with Quasiparticle-Phonon Model (QPM) calculations provides insight into the relevance of different giant resonance decay mechanisms. Photoabsorption cross sections derived from the data assuming dominance of relativistic Coulomb excitation are in fair agreement with previous work using real photons.Comment: 15 pages, 15 figure

    Magnetization of densely packed interacting magnetic nanoparticles with cubic and uniaxial anisotropies: A Monte Carlo study

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    International audienceThe magnetization curves of densely packed single domain magnetic nanoparticles (MNP) are investigated by Monte Carlo simulations in the framework of an effective one spin model. The particles whose size polydispersity is taken into account are arranged in spherical clusters and both dipole dipole interactions (DDI) and magnetic anisotropy energy (MAE) are included in the total energy. Having in mind the special case of spinel ferrites of intrinsic cubic symmetry, combined cubic and uniaxial magnetocrystalline anisotropies are considered with different configurations for the orientations of the cubic and uniaxial axes. It is found that the DDI, together with a marked reduction of the linear susceptibility are responsible for a damping of the peculiarities due to the MAE cubic component on the magnetization. As an application, we show that the simulated magnetization curves compare well to experimental results for γ\gamma--Fe2_2O3_3 MNP for small to moderate values of the field
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