Board Characteristics, Ownership Structure and Agency Costs: UK Evidence

The term “Corporate Governance” always proliferates after large accounting scandals and crises; practitioners claim that governance mechanisms are the cause of these failures, and worldwide reforms take place after each failure; however, these reforms did not succeed in preventing the subsequent falls down. Although corporate governance mechanisms are introduced to monitor and control the managerial opportunistic behaviour in order to reduce the agency costs; most of the prior studies were directed towards investigating the role of governance mechanisms in enhancing firm performance as an indirect proxy of lower agency conflicts, and hence, lower agency costs. This study adds to the debate around the usefulness and the effectiveness of the corporate governance mechanisms in controlling the managerial opportunistic behaviour and reducing agency costs. This study contributes to the governance literature by investigating and comparing the impact of a comprehensive set of governance mechanisms reflecting a wide spectrum of board characteristics and ownership structure on agency costs over the period 2005-2011; in addition to providing a comparison of before and after the financial crisis periods using a large sample of firms listed in FTSE All-Share index. In doing so, two different agency costs proxies are utilised; asset utilisation which reflects the managerial efficiency; and the interaction of free cash flow with growth opportunities which reflects investment decisions agency costs. This comparative analysis extends the governance literature that investigated the pre and during the crisis periods by adding the pre and post the 2008 financial crisis comparison. Lastly, this study considers more than one theoretical paradigm; the empirical evidence lends the support to the agency and resource dependence perspectives and provides partial support to the stewardship view. The results clearly show that not all governance mechanisms lead to lower agency costs; thus, one prescribed structure does not fit all. Moreover, the efficiency of the governance mechanisms is directly affected by surrounding economic conditions (e.g., steady and abnormal conditions); in other words, governance mechanisms which help in reducing agency costs during the normal economic condition could turn out to be useless, inefficient and in some cases detrimental to the managerial effectiveness after the financial crisis. Moreover, the reported results support the claim that interrelation between the different governance mechanisms should be considered in future governance studies

MAXIMUM POWER TRACKING OF A GRID-CONNECTED WIND-DRIVEN BRUSHLESS DOUBLY-FED RELUCTANCE GENERATOR USING SCALAR CONTROL

This paper presents a scalar volt per hertz (v/f) control technique for maximum power tracking of a grid-connected wind-driven Brushless Doubly-Fed Reluctance Generator (BDFRG). The proposed generator has two stator windings namely; power winding, directly connected to the grid, and control winding, connected to the grid through a bi-directional converter. The presented control technique is based on the abc-axis and dq-axis dynamic model of BDFRG. A detailed abc-axis and dq-axis dynamic model, by which the dynamic behaviour of the BDFRG can be successfully predicted under different operating conditions, is presented. In addition, a soft starting method is suggested to avoid the over-current of the bi-directional converter. The presented simulation results ensure the effectiveness of the proposed control strategy for maximum wind-power extraction under wind-speed variations

A stochastic Model for Predicting Irrigation Water Requirements (IWR)

The main objective of this paper is to develop a stochastic time series model with trend, periodic and irregular components using a ten years IWR decade data for three different types of cotton crops cultivated in Gezira Scheme, SUDAN. The model was applied to cotton Brackat and then used to Shmbat & Akala cotton. In the analysis of IWR time series the correlogram technique was used to detect the periodicity which then smoothed by Fourier series method. The series is then tested for stationary and the dependent part of irregular component is found to be well expressed by the first order autoregressive model for all the crops. The developed model superimposes a periodic-deterministic process and an irregular componen

VisIVOWeb: A WWW Environment for Large-Scale Astrophysical Visualization

This article presents a newly developed Web portal called VisIVOWeb that aims to provide the astrophysical community with powerful visualization tools for large-scale data sets in the context of Web 2.0. VisIVOWeb can effectively handle modern numerical simulations and real-world observations. Our open-source software is based on established visualization toolkits offering high-quality rendering algorithms. The underlying data management is discussed with the supported visualization interfaces and movie-making functionality. We introduce VisIVOWeb Network, a robust network of customized Web portals for visual discovery, and VisIVOWeb Connect, a lightweight and efficient solution for seamlessly connecting to existing astrophysical archives. A significant effort has been devoted for ensuring interoperability with existing tools by adhering to IVOA standards. We conclude with a summary of our work and a discussion on future developments

Molar-Incisor hypomineralization in controls vs CLP with primary or prior to secondary alveolar grafts

poster abstractMolar incisor hypomineralization (MIH) is a congenital defect of unknown etiology that can affect both esthetics and cariogenic susceptibility. The objective of this study was to determine whether MIH is greater in patients with cleft lip and palate (CLP) who underwent primary alveolar grafting (PAG) as compared to CLP prior to secondary alveolar grafting (SAG) and to controls. A retrospective analysis of intraoral photographs of 13 (10M:3F; 8.9 ± 1.2 yrs) CLP patients who underwent a PAG, 27 (18M:9F;10.0 ± 2.1 yrs) CLP prior to SAG, and 60 (30M:30F; 12.4 ± 1.8 yrs) controls without CLP was performed. Mantel-Haenszel chi-square tests were used to compare the three groups for differences in MIH scores and Wilcoxon Rank Sum tests were used to compare the groups for differences in average MIH scores. A 5% significance level was used for all tests. MIH scores were significantly higher for the PAG and SAG groups compared to the control group (p<0.001). The PAG group had significantly higher incisor MIH (p=0.016) than the SAG group. MIH average scores were significantly higher for the two graft groups compared to the controls (p<0.0001). The PAG group had significantly higher average MIH score and average MIH score for incisors than the SAG group (p=0.03). The results suggest that CLP patients, in general, have significantly greater MIH compared with controls and CLP with PAGs have significantly greater MIH in the incisor region than CLP waiting for SAGs. The increased severity of MIH could be related to the grafting during the time of incisor crown formation

A Systematic Search for High Surface Brightness Giant Arcs in a Sloan Digital Sky Survey Cluster Sample

We present the results of a search for gravitationally-lensed giant arcs conducted on a sample of 825 SDSS galaxy clusters. Both a visual inspection of the images and an automated search were performed and no arcs were found. This result is used to set an upper limit on the arc probability per cluster. We present selection functions for our survey, in the form of arc detection efficiency curves plotted as functions of arc parameters, both for the visual inspection and the automated search. The selection function is such that we are sensitive only to long, high surface brightness arcs with g-band surface brightness mu_g 10. Our upper limits on the arc probability are compatible with previous arc searches. Lastly, we report on a serendipitous discovery of a giant arc in the SDSS data, known inside the SDSS Collaboration as Hall's arc.Comment: 34 pages,8 Fig. Accepted ApJ:Jan-200

The Fundamental Surface of Quad Lenses

In a quadruply imaged lens system the angular distribution of images around the lens center is completely described by three relative angles. We show empirically that in the 3D space of these angles, spanning 180 x 180 x 90 degrees, quads from simple two-fold symmetric lenses of arbitrary radial density profile and arbitrary radially dependent ellipticity or external shear define a nearly invariant 2D surface. We give a fitting formula for the surface using SIS+elliptical lensing potential. Various circularly symmetric mass distributions with shear up to 0.4 deviate from it by typically, rms~0.1 deg, while elliptical mass distributions with ellipticity of up 0.4 deviate from it by rms~1.5 deg. The existence of a near invariant surface gives a new insight into the lensing theory and provides a framework for studying quads. It also allows one to gain information about the lens mass distribution from the image positions alone, without any recourse to mass modeling. As an illustration, we show that about 3/4 of observed galaxy-lens quads do not belong to this surface within observational error, and so require additional external shear or substructure to be modeled adequately.Comment: 24 pages, 9 figures, accepted to MNRA

Robust seed selection algorithm for k-means type algorithms

Selection of initial seeds greatly affects the quality of the clusters and in k-means type algorithms. Most of the seed selection methods result different results in different independent runs. We propose a single, optimal, outlier insensitive seed selection algorithm for k-means type algorithms as extension to k-means++. The experimental results on synthetic, real and on microarray data sets demonstrated that effectiveness of the new algorithm in producing the clustering resultsComment: 17 pages, 5 tables, 9figure