American trade policy towards Sub Saharan Africa –- a meta analysis of AGOA

Twelve econometric studies investigating the impact of agoa presented in this paper have reported 174 different estimates. In testing for publication bias and whether there is a genuine empirical impact of agoa we resort to a meta-analysis. The meta-analysis provides us with a formal means of testing for publication bias and an empirical effect. The result shows significant publication bias in the selected studies. However, in a few cases the test for a genuine effect is passed successfully. The results of the meta-analysis indicates that agoa increased the trade of beneficiaries by 13.2%

American trade policy towards Sub Saharan Africa –- a meta analysis of AGOA

Twelve econometric studies investigating the impact of agoa presented in this paper have reported 174 different estimates. In testing for publication bias and whether there is a genuine empirical impact of agoa we resort to a meta-analysis. The meta-analysis provides us with a formal means of testing for publication bias and an empirical effect. The result shows significant publication bias in the selected studies. However, in a few cases the test for a genuine effect is passed successfully. The results of the meta-analysis indicates that agoa increased the trade of beneficiaries by 13.2%.Trade preference regimes; African Growth and Opportunity Act (AGOA); Publication bias; Meta-Regression Analysis; Funnel plot; Study effect

An Elastic Analysis of a Plated Bone to Determine Fracture Gap Motion

An elastic analysis to determine fracture gap motions occurring in the osteotomized and plated canine femur was performed using the finite element program NASTRAN. The femur was idealized as a hollow right cylinder, and transverse anisotropy was assumed for the elastic properties of the bone. A 3-D 360 degree model consisting of 224 isoparametric quadrilateral hexahedral and 11 beam elements was created. A range of plate stiffnesses was tested by varying the modulus of elasticity of the plate from 207 GPa to 1 GPA. Moments were applied in the plane of the plate, about the axis of the plate, and in the plane of the screws. Results showed that, for plates of typical geometry and elastic modulus under 10 GPa, the contribution to fracture gap motion occurring due to deformation in the bone was negligible compared to that contribution from deformation in the plate

Fault tolerant control of a quadrotor using L-1 adaptive control

Purpose – The growing use of small unmanned rotorcraft in civilian applications means that safe operation is increasingly important. The purpose of this paper is to investigate the fault tolerant properties to faults in the actuators of an L1 adaptive controller for a quadrotor vehicle. Design/methodology/approach – L1 adaptive control provides fast adaptation along with decoupling between adaptation and robustness. This makes the approach a suitable candidate for fault tolerant control of quadrotor and other multirotor vehicles. In the paper, the design of an L1 adaptive controller is presented. The controller is compared to a fixed-gain LQR controller. Findings – The L1 adaptive controller is shown to have improved performance when subject to actuator faults, and a higher range of actuator fault tolerance. Research limitations/implications – The control scheme is tested in simulation of a simple model that ignores aerodynamic and gyroscopic effects. Hence for further work, testing with a more complete model is recommended followed by implementation on an actual platform and flight test. The effect of sensor noise should also be considered along with investigation into the influence of wind disturbances and tolerance to sensor failures. Furthermore, quadrotors cannot tolerate total failure of a rotor without loss of control of one of the degrees of freedom, this aspect requires further investigation. Practical implications – Applying the L1 adaptive controller to a hexrotor or octorotor would increase the reliability of such vehicles without recourse to methods that require fault detection schemes and control reallocation as well as providing tolerance to a total loss of a rotor. Social implications – In order for quadrotors and other similar unmanned air vehicles to undertake many proposed roles, a high level of safety is required. Hence the controllers should be fault tolerant. Originality/value – Fault tolerance to partial actuator/effector faults is demonstrated using an L1 adaptive controller

Global trends and challenges to the HR profession.

The outsourcing of HR activities is a management strategy that may be adopted in response to a number of pressures that an organization is faced with. It is one aspect of business process outsourcing that is increasingly deployed by firms in order to enhance their organizational competitiveness. HR outsourcing can be defined as ‘placing responsibility for various elements of the HR function with a third-party provider’ (Turnbull, 2002, p.11). In spite of the perceived benefits of HR outsourcing and its growth predicted by consultancy firms and HR outsourcing market leaders, the growth of outsourcing remains cautious and the benefits of doing so prove limited. This paper provides an overview of reasons why firms outsource their HR activities, its growth trends, organizational change that may be triggered by the outsourcing decision, and the challenges that are presented to the HR function and professionals as a result. The paper argues that a number of conceptual ambiguities and operational pitfalls may dampen the effectiveness of HR outsourcing for user organizations

Spin-one ferromagnets with single-ion anisotropy in a perpendicular external field

In this paper, the conventional Holstein-Primakoff method is generalized with the help of the characteristic angle transformation [Lei Zhou and Ruibao Tao, J. Phys. A {\bf 27} 5599 (1994)] for the spin-one magnetic systems with single-ion anisotropies. We find that the weakness of the conventional method for such systems can be overcome by the new approach. Two models will be discussed to illuminate the main idea, which are the ``easy-plane" and the ``easy-axis" spin-one ferromagnet, respectively. Comparisons show that the current approach can give reasonable ground state properties for the magnetic system with ``easy-plane" anisotropy though the conventional method never can, and can give a better representation than the conventional one for the magnetic system with ``easy-axis" anisotropy though the latter is usually believed to be a good approximation in such case. Study of the easy-plane model shows that there is a phase transition induced by the external field, and the low-temperature specific heat may have a peak as the field reaches the critical value.Comment: Using LaTex. To be published in the September 1 issue of Physical Review B (1996). Email address: [email protected]

Ascospore color mutants and low germination in Neurospora

Ascospore color mutants and low germinatio

Germination of certain genotypes in response to furfural

Germination of certain genotypes in response to furfura

Fungal genetics course based on Coniochaeta.

Fungal genetics course based on Coniochaeta

3D image analysis for pedestrian detection

A method for solving the dense disparity stereo correspondence problem is presented in this paper. This technique is designed specifically for pedestrian detection type applications. A new Ground Control Points (GCPs) scheme is introduced, using groundplane homography information to determine regions in which good GCPs are likely to occur. The method also introduces a dynamic disparity limit constraint to further improve GCP selection and dense disparity generation. The technique is applied to a real world pedestrian detection scenario with a background modeling system based on disparity and edges