A computational study of 13-atom Ne-Ar cluster heat capacities

Heat capacity curves as functions of temperature were calculated using Monte Carlo methods for the series of Ne_(13-n)Ar_n clusters (0 <= n <= 13). The clusters were modeled classically using pairwise additive Lennard-Jones potentials. The J-walking (or jump-walking) method was used to overcome systematic errors due to quasiergodicity. Substantial discrepancies between the J-walking results and those obtained using standard Metropolis methods were found. Results obtained using the atom-exchange method, another Monte Carlo variant for multi-component systems, also did not compare well with the J-walker results. Quench studies were done to investigate the clusters' potential energy surfaces. Only those Ne-Ar clusters consisting predominately of either one or the other component had lowest energy isomers having the icosahedral-like symmetry typical of homogeneous 13-atom rare gas clusters; non-icosahedral structures dominated the lowest-energy isomers for the other clusters. This resulted in heat capacity curves that were very much different than that of their homogeneous counterpart. Evidence for coexistence behavior different than that seen in homogenous clusters is also presented.Comment: 45 pages, 11 Figures, figures in .gif format files. Journal of Chemical Physics, AIP ID number 513730JC

A Computational Study of Thirteen-atom Ar-Kr Cluster Heat Capacities

Heat capacity curves as functions of temperature were calculated using Monte Carlo methods for the series of Ar_{13-n}Kr_n clusters (0 <= n <= 13). The clusters were modeled classically using pairwise additive Lennard-Jones potentials. J-walking (or jump-walking) was used to overcome convergence difficulties due to quasiergodicity present in the solid-liquid transition regions, as well as in the very low temperature regions where heat capacity anomalies arising from permutational isomers were observed. Substantial discrepancies between the J-walking results and the results obtained using standard Metropolis Monte Carlo methods were found. Results obtained using the atom-exchange method, another Monte Carlo variant designed for multi-component systems, were mostly similar to the J-walker results. Quench studies were also done to investigate the clusters' potential energy surfaces; in each case, the lowest energy isomer had an icosahedral-like symmetry typical of homogeneous thirteen-atom rare gas clusters, with an Ar atom being the central atom.Comment: 46 pages, 13 Figures combined in 2 .gif files, Journal of Chemical Physics, AIP ID number 508646JC

Boards Of Advisors In Small Businesses: An Empirical Profile Of Their Composition And Use

This article discusses the literature coverage on Boards of Advisors to date and provides the results of a study designed to determine the formation and composition of Boards of Advisors and the ways in which small businesses use such boards. Our study surveyed the Chief Executive Officers or Presidents of a large sample of small businesses. We found that there is very limited use of Boards of Advisors in small businesses and that many small business managers are not aware of the concept of a Board of Advisors. However, those small business managers (97%) that use a Board of Advisors characterize their interaction with their Boards of Advisors as good or excellent. When selecting board members, the responding executives seek practical experience, good “common sense” and industry experience as the most important types of expertise. Most board members were male (67%), active in business (90%), have managerial/strategy or law (52%) and are not compensated (53%)

Applying Sarbanes-Oxley Principles to Colleges and Universities

In the wake of the financial scandals that have occurred in the corporate sector, the public is demanding more accountability not only from corporations but also from nonprofit organizations such as universities. Institutions can enhance corporate governance by implementing some of the principles and procedures the Sarbanes-Oxley Act of 2002 (SOX) have mandated for public companies. Because public accounting firms audit universities, the firms can provide a valuable service to such clients by recommending ways in which universities can implement SOX practices that are appropriate and applicable. Although SOX does not currently apply to colleges and universities, it has created a climate in which many colleges and universities are considering ways to increase transparency and accountability in their financial operations. The outlook for mandating SOX-like legislation for nonprofits is unclear, both at the federal and state level. There is evidence, however, of some opposition to the implementation of SOX principles at universities

Is systematic downside beta risk really priced? Evidence in emerging market data

Several studies advocating safety first as a major concern to investors propose downside beta risk as an alternative to the traditional systematic risk-beta. Downside measures are concerned with a subset of the data and therefore the results in the studies that consider the downside beta only may be biased. This study addresses this issue by including downside co-skewness risk in addition to the downside beta risk in the pricing model. In a sample of 27 emerging markets two-stage rolling regression analysis fails to support pricing models with downside risk measures. In a cross-sectional analysis inclusion of downside co-skewness improves model fit. When considered together, downside beta is potential and downside co-skewness is a risk to the rational investor. Even though our results are inconclusive the evidence strongly suggests a need for further investigation of co-skewness risk in pricing models that adopt a downside risk framework.Beta, Downside risk, Emerging markets