Tentative Detection of the Rotation of Eris

We report a multi-week sequence of B-band photometric measurements of the dwarf planet Eris using the {\it Swift} satellite. The use of an observatory in low-Earth orbit provides better temporal sampling than is available with a ground-based telescope. We find no compelling evidence for an unusually slow rotation period of multiple days, as has been suggested previously. A $\sim$1.08 day rotation period is marginally detected at a modest level of statistical confidence ($\sim$97%). Analysis of the combination of the $Swift$ data with the ground-based B-band measurements of \citet{2007AJ....133...26R} returns the same period ($\sim$1.08 day) at a slightly higher statistical confidence ($\sim$99%).Comment: Accepted to Icarus 2008-Aug-19. 19 pages total, including 4 figures and 1 tabl

Tunneling and Non-Universality in Continuum Percolation Systems

The values obtained experimentally for the conductivity critical exponent in numerous percolation systems, in which the interparticle conduction is by tunnelling, were found to be in the range of $t_0$ and about $t_0+10$, where $t_0$ is the universal conductivity exponent. These latter values are however considerably smaller than those predicted by the available ``one dimensional"-like theory of tunneling-percolation. In this letter we show that this long-standing discrepancy can be resolved by considering the more realistic "three dimensional" model and the limited proximity to the percolation threshold in all the many available experimental studiesComment: 4 pages, 2 figure

Intellectual Capital Disclosure in Knowledge Rich Firms: The Impact of Market and Corporate Governance Factors

YesIntellectual capital disclosure (ICD) in corporate annual reports has received growing European attention. To date, few studies have undertaken systematic analysis of the factors influencing the decision to disclose Intellectual Capital (IC) related information in annual reports. The purpose of this paper is to examine whether the level of hidden value (market-to-book ratio), share price volatility, listing age, board composition, ownership structure, audit committee size and directors’ shareholding, in addition to other firm specific factors influence ICD in 100 UK listed knowledge-rich firms. The dependent variable is measured by a 183 item index score, supported by word count and percentage of IC word count metrics to assess the extent, volume and focus of ICD respectively. Results of the analysis based on the three measures indicate significant association with hidden value, using market-to-book ratio as a proxy, and listing age. We further find firm size, share price volatility, director shareholding, audit committee size, and ownership concentration to be associated with ICD in a manner consistent with theoretical expectations. The implications of these findings, hitherto largely untested, are explored from a number of theoretical perspectives

Intellectual Capital Disclosures in Corporate Annual Reports: A European Comparison

YesThe extent of intellectual capital (IC) disclosures in corporate annual reports has received increasing attention in recent years. This paper is an exploratory study that considers the efficacy of various IC disclosure measures. It draws on annual reports of leading firms within the financial services sector in nine Western European countries. Content analysis was employed to produce measures based on disclosure indexes and word count to assess the variety, volume and focus of IC in annual reports. Disclosure scores were computed using three forms of presentation - any form, numerical form (reflecting more ‘objective’ disclosure), and all forms. Generally, we found that the form of disclosure index did not significantly affect IC sample rankings and were broadly in line with the IC word count rankings. However, very different rankings emerged when using the focus measure (IC word count as a percentage of total word count in Annual Report). We argue that this measure of relative importance is an important measure, particularly because firm size is typically positively associated with disclosure. Variation in the form of IC (human, structural, relational) is also explored. The paper then reports the findings of a time series analysis of the IC disclosure practices within a UK bank over a 10-year period. Significant variation in IC disclosure was found, with a strong movement in IC content from human capital to relational capital. These findings are discussed

Further studies of space-time clustering of Burkitt's lymphoma in Uganda.

All hospital-treated cases of Burkitt's lymphoma (BL), with onset of symptoms in the period 1963-68 and resident in the Lango and Acholi districts of Uganda, were identified. The average annual incidence of BL in the 6-year period was 1-87 X 10(-5), similar to that in the adjacent West Nile district. Contrary to findings in other areas of Uganda, there was no evidence of seasonal variation in the onset of cases, nor of space-time clustering, nor of a decline in the incidence of BL in the study period. An inverse relationship was noted between the median age at onset of BL and the incidence of the disease in different areas of Uganda, a finding consistent with intense malarial infection being a precipitating factor for BL. The variable observations with respect to space-time clustering of BL and seasonal variation in incidence in different areas remains unexplained, but it is suggested that a closer study of the patterns of malarial infection in these areas may help to account for the findings

Proceedings of the Spacecraft Charging Technology Conference: Executive Summary

Aerospace environments are reviewed in reference to spacecraft charging. Modelling, a theoretical scheme which can be used to describe the structure of the sheath around the spacecraft and to calculate the charging currents within, is discussed. Materials characterization is considered for experimental determination of the behavior of typical spacecraft materials when exposed to simulated geomagnetic substorm conditions. Materials development is also examined for controlling and minimizing spacecraft charging or at least for distributing the charge in an equipotential manner, using electrical conductive surfaces for materials exposed to space environment

Percolation Threshold, Fisher Exponent, and Shortest Path Exponent for 4 and 5 Dimensions

We develop a method of constructing percolation clusters that allows us to build very large clusters using very little computer memory by limiting the maximum number of sites for which we maintain state information to a number of the order of the number of sites in the largest chemical shell of the cluster being created. The memory required to grow a cluster of mass s is of the order of $s^\theta$ bytes where $\theta$ ranges from 0.4 for 2-dimensional lattices to 0.5 for 6- (or higher)-dimensional lattices. We use this method to estimate $d_{\scriptsize min}$, the exponent relating the minimum path $\ell$ to the Euclidean distance r, for 4D and 5D hypercubic lattices. Analyzing both site and bond percolation, we find $d_{\scriptsize min}=1.607\pm 0.005$ (4D) and $d_{\scriptsize min}=1.812\pm 0.006$ (5D). In order to determine $d_{\scriptsize min}$ to high precision, and without bias, it was necessary to first find precise values for the percolation threshold, $p_c$: $p_c=0.196889\pm 0.000003$ (4D) and $p_c=0.14081\pm 0.00001$ (5D) for site and $p_c=0.160130\pm 0.000003$ (4D) and $p_c=0.118174\pm 0.000004$ (5D) for bond percolation. We also calculate the Fisher exponent, $\tau$, determined in the course of calculating the values of $p_c$: $\tau=2.313\pm 0.003$ (4D) and $\tau=2.412\pm 0.004$ (5D)