Linear energy divergences in Coulomb gauge QCD

The structure of linear energy divergences is analysed on the example of one graph to 3-loop order. Such dangerous divergences do cancel when all graphs are added, but next to leading divergences do not cancel out.Comment: 6 pages, 1 figur

Mapping Cluster Mass Distributions via Gravitational Lensing of Background Galaxies

We present a new method for measuring the projected mass distributions of galaxy clusters. The gravitational amplification is measured by comparing the joint distribution in redshift and magnitude of galaxies behind the cluster with that of field galaxies. We show that the total amplification is directly related to the surface mass density in the weak field limit, and so it is possible to map the mass distribution of the cluster. The method is shown to be limited by discreteness noise and galaxy clustering behind the lens. Galaxy clustering sets a lower limit to the error along the redshift direction, but a clustering independent lensing signature may be obtained from the magnitude distribution at fixed redshift. Statistical techniques are developed for estimating the surface mass density of the cluster. We extend these methods to account for any obscuration by cluster halo dust, which may be mapped independently of the dark matter. We apply the method to a series of numerical simulations and show the feasibility of the approach. We consider approximate redshift information, and show how the mass estimates are degraded.Comment: ApJ in press. 23 pages of LaTeX plus figs. Text & figs available by anonymous ftp from resun03.roe.ac.uk in directory /pub/jap/lens (you need btp.tex and apj.sty

Nonlinear Cosmological Power Spectra in Real and Redshift--Space

We present an expression for the nonlinear evolution of the cosmological power spectrum based on following Lagrangian trajectories. This is simplified using the Zel'dovich approximation to trace particle displacements, assuming Gaussian initial conditions. The model is found to exhibit the transfer of power from large to small scales expected in self- gravitating fields. We have extended this analysis into redshift-space and found a solution for the nonlinear, anisotropic redshift-space power spectrum in the limit of plane--parallel redshift distortions. The quadrupole-to- monopole ratio is calculated for the case of power-law initial spectra. We find that the shape of this ratio depends on the shape of the initial spectrum, but when scaled to linear theory depends only weakly on the redshift-space distortion parameter, $\beta$. The point of zero-crossing of the quadrupole, $k_0$, is found to obey a scaling relation. This model is found to be in agreement with $N$-body simulations on scales down to the zero-crossing of the quadrupole, although the wavenumber at zero-crossing is underestimated. These results are applied to the quadrupole--monopole ratio found in the merged QDOT+1.2 Jy IRAS redshift survey. We have estimated that the distortion parameter is constrained to be $\beta>0.5$ at the $95 \%$ level. The local primordial spectral slope is not well constrained, but analysis suggests $n \approx -2$ in the translinear regime. The zero-crossing scale of the quadrupole is $k_0=0.5 \pm 0.1 h/Mpc$ and from this we infer the amplitude of clustering is $\sigma_8=0.7 \pm 0.05$. We suggest that the success of this model is due to nonlinear redshift--space effects arising from infall onto caustics and is not dominated by virialised cluster cores.Comment: 13 pages, uufiles, Latex with 6 postscript figures, submitted to MNRA

The value relevance of disclosures of liabilities of equity-accounted investees: UK evidence

This study examines the value relevance of mandated disclosures by UK firms of the investor-firm share of liabilities of equity-accounted associate and joint venture investees. It does so for the six years following the introduction of FRS 9: Associates and Joint Ventures, which forced a substantial increase in such disclosures by UK firms. Since the increased disclosure requirements were partly motivated by concern that single-line equity accounting concealed the level of group gearing, and in light of previous US results, it is predicted that the mandated investee-liability disclosures have a negative coefficient in a value-relevance regression. The study also examines whether value-relevance regression coefficients on investee-liability disclosures are more negative for joint ventures than for associates and whether they are more negative in the presence of investor-firm guarantees of investee-firm obligations than in the absence of such guarantees. The study reports that the coefficient on all investee-liability disclosures taken together has the predicted negative sign, and is significantly different from zero. It finds little evidence that the negative valuation impact of liability disclosures is stronger for joint venture investees overall than for associate investees overall, or stronger for guarantee cases overall than for non-guarantee cases overall. There is, however, some evidence that the impact for joint venture guarantee cases is stronger than that for joint venture non-guarantee cases and stronger than that for associate guarantee cases