The Impact of BSE in Cattle on High-Nature Value Conservation Sites in England

The BSE (mad-cow disease) crisis has had severe impacts on the beef sector in English agriculture, evident primarily through the low prices since experienced by farm businesses for beef cattle at market and the European Union (EU) ban on British beef exports. However, the extent to which resultant changes in beef cattle enterprises have affected conservation sites of high-nature value is less well-known. This paper reports on empirical research conducted into beef grazing on 50 Sites of Special Scientific Interest (SSSIs), England's best protected conservation areas. The crisis is found to have caused localized problems with overgrazing of Sites due to restrictions in stock movements after the crisis, undergrazing as farmers rationalize their beef enterprises and more subtle ecological changes associated with grazing habitats of different species and breeds of livestock. Direct impacts are not always clear, but BSE is undoubtedly making the delivery of nature conservation objectives more difficult in England

Light-Front Bethe-Salpeter Equation

A three-dimensional reduction of the two-particle Bethe-Salpeter equation is proposed. The proposed reduction is in the framework of light-front dynamics. It yields auxiliary quantities for the transition matrix and the bound state. The arising effective interaction can be perturbatively expanded according to the number of particles exchanged at a given light-front time. An example suggests that the convergence of the expansion is rapid. This result is particular for light-front dynamics. The covariant results of the Bethe-Salpeter equation can be recovered from the corresponding auxiliary three-dimensional ones. The technical procedure is developed for a two-boson case; the idea for an extension to fermions is given. The technical procedure appears quite practicable, possibly allowing one to go beyond the ladder approximation for the solution of the Bethe-Salpeter equation. The relation between the three-dimensional light-front reduction of the field-theoretic Bethe-Salpeter equation and a corresponding quantum-mechanical description is discussed.Comment: 42 pages, 5 figure

A minimal model for excitons within time-dependent density-functional theory

The accurate description of the optical spectra of insulators and semiconductors remains an important challenge for time-dependent density-functional theory (TDDFT). Evidence has been given in the literature that TDDFT can produce bound as well as continuum excitons for specific systems, but there are still many unresolved basic questions concerning the role of dynamical exchange and correlation (xc). In particular, the role of the long spatial range and the frequency dependence of the xc kernel $f_{\rm xc}$ for excitonic binding are still not very well explored. We present a minimal model for excitons in TDDFT, consisting of two bands from a one-dimensional Kronig-Penney model and simple approximate xc kernels, which allows us to address these questions in a transparent manner. Depending on the system, it is found that adiabatic xc kernels can produce a single bound exciton, and sometimes two bound excitons, where the long spatial range of $f_{\rm xc}$ is not a necessary condition. It is shown how the Wannier model, featuring an effective electron-hole interaction, emerges from TDDFT. The collective, many-body nature of excitons is explicitly demonstrated.Comment: 12 pages, 11 figure

Antecedents of Voluntary Corporate Governance Disclosure: A Post-2007/08 Financial Crisis Evidence from the Influential UK Combined Code

Purpose: This study investigates the level of compliance with, and disclosure of, good corporate governance (CG) practices among UK publicly listed firms, and consequently ascertains whether board characteristics and ownership structure variables can explain observable differences in the extent of voluntary CG compliance and disclosure practices. Design/Methodology/Approach: The study uses one of the largest datasets to-date on compliance and disclosure of CG practices from 2008 to 2013 containing 120 CG provisions drawn from the 2010 UK Combined Code relating to 100 UK listed firms to conduct multiple regression analyses of the determinants of voluntary CG disclosures. A number of additional estimations, including two stage least squares, fixed-effects and lagged structures, are conducted in order to test the robustness of the findings. Findings: The results suggest that there is a substantial variation in the levels of compliance with, and disclosure of, good CG practices among the sampled UK firms. We also find that firms with larger board size, more independent outside directors and greater director diversity tend to disclose more CG information voluntarily, whereas the level of voluntary CG compliance and disclosure is insignificantly related to the existence of a separate CG committee and institutional ownership. Additionally, the results indicate that block ownership and managerial ownership impact negatively on voluntary CG compliance and disclosure practices. The findings are fairly robust across a number of econometric models that sufficiently address various endogeneity problems and alternative CG indices. Overall, the findings are generally consistent with the predictions of neo-institutional theory. Originality/Value: This paper extends, as well as contributes to the extant CG literature by offering new evidence on compliance with, and disclosure of, good CG recommendations contained in the 2010 UK Combined Code following the 2007/08 global financial crisis. This paper also advances the existing literature by offering new insights from a neo-institutional theoretical perspective of the impact of board and ownership mechanisms on voluntary CG compliance and disclosure practices. Keywords: Corporate governance; Board and ownership mechanisms; Comply or explain; Neo-institutional theory; UK Combined Cod

Radiogenic power and geoneutrino luminosity of the Earth and other terrestrial bodies through time

We report the Earth's rate of radiogenic heat production and (anti)neutrino luminosity from geologically relevant short-lived radionuclides (SLR) and long-lived radionuclides (LLR) using decay constants from the geological community, updated nuclear physics parameters, and calculations of the $\beta$ spectra. We track the time evolution of the radiogenic power and luminosity of the Earth over the last 4.57 billion years, assuming an absolute abundance for the refractory elements in the silicate Earth and key volatile/refractory element ratios (e.g., Fe/Al, K/U, and Rb/Sr) to set the abundance levels for the moderately volatile elements. The relevant decays for the present-day heat production in the Earth ($19.9\pm3.0$ TW) are from $^{40}$K, $^{87}$Rb, $^{147}$Sm, $^{232}$Th, $^{235}$U, and $^{238}$U. Given element concentrations in kg-element/kg-rock and density $\rho$ in kg/m$^3$, a simplified equation to calculate the present day heat production in a rock is: $$h \, [\mu \text{W m}^{-3}] = \rho \left( 3.387 \times 10^{-3}\,\text{K} + 0.01139 \,\text{Rb} + 0.04595\,\text{Sm} + 26.18\,\text{Th} + 98.29\,\text{U} \right)$$ The radiogenic heating rate of Earth-like material at Solar System formation was some 10$^3$ to 10$^4$ times greater than present-day values, largely due to decay of $^{26}$Al in the silicate fraction, which was the dominant radiogenic heat source for the first $\sim10$ Ma. Assuming instantaneous Earth formation, the upper bound on radiogenic energy supplied by the most powerful short-lived radionuclide $^{26}$Al ($t_{1/2}$ = 0.7 Ma) is 5.5$\;\times\;$10$^{31}$ J, which is comparable (within a factor of a few) to the planet's gravitational binding energy.Comment: 28 pages, 6 figures, 5 table

Myopic investment view of the Indian mutual fund industry

This paper examines the investment behavior of Indian mutual fund industry. Since the majority of investors who invest in mutual funds are salaried individuals or individuals that own SMEs, the Indian Mutual Fund industry should have a long term investment horizon. However, the data from all mutual funds for the periods December 2007 to May 2008 and December 2008 to May 2009 reveals that the mutual fund industry has adjusted its position on a short term basis in tandem with the short term volatility of the market. The findings substantiate the SEBI Chairman’s observation that there is an urgent need to set up investment norms with regard to the holding period for stocks owned by the Indian mutual fund industryMutual Fund, short term volatility, asset under management, investment churn.

A semiparametric Bayesian approach to the analysis of financial time series with applications to value at risk estimation

Financial time series analysis deals with the understanding of data collected on financial markets. Several parametric distribution models have been entertained for describing, estimating and predicting the dynamics of financial time series. Alternatively, this article considers a Bayesian semiparametric approach. In particular, the usual parametric distributional assumptions of the GARCH-type models are relaxed by entertaining the class of location-scale mixtures of Gaussian distributions with a Dirichlet process prior on the mixing distribution, leading to a Dirichlet process mixture model. The proposed specification allows for a greater exibility in capturing both the skewness and kurtosis frequently observed in financial returns. The Bayesian model provides statistical inference with finite sample validity. Furthermore, it is also possible to obtain predictive distributions for the Value at Risk (VaR), which has become the most widely used measure of market risk for practitioners. Through a simulation study, we demonstrate the performance of the proposed semiparametric method and compare results with the ones from a normal distribution assumption. We also demonstrate the superiority of our proposed semiparametric method using real data from the Bombay Stock Exchange Index (BSE-30) and the Hang Seng Index (HSI).Bayesian estimation, Deviance information criterion, Dirichlet process mixture, Financial time series, Location-scale Gaussian mixture, Markov chain Monte Carlo