Next-to-Leading Order QCD Analysis of Polarized Deep Inelastic Scattering Data

We present a Next-to-Leading order perturbative QCD analysis of world data on the spin dependent structure functions $g_1^p, g_1^n$, and $g_1^d$, including the new experimental information on the $Q^2$ dependence of $g_1^n$. Careful attention is paid to the experimental and theoretical uncertainties. The data constrain the first moments of the polarized valence quark distributions, but only qualitatively constrain the polarized sea quark and gluon distributions. The NLO results are used to determine the $Q^2$ dependence of the ratio $g_1/F_1$ and evolve the experimental data to a constant $Q^2 = 5 GeV^2$. We determine the first moments of the polarized structure functions of the proton and neutron and find agreement with the Bjorken sum rule.Comment: 21 pages, 4 figures; final version to be published in Phys. Lett. B. References updated. Uses elsart.cls version 1996/04/22, 2e-1.4

Age-and tactic-related paternity success in male African elephants

Information on age-and tactic-related paternity success is essential for understanding the lifetime reproductive strategy of males and constitutes an important component of the fitness trade-offs that shape the life-history traits of a species. The degree of reproductive skew impacts the genetic structure of a population and should be considered when developing conservation strategies for threatened species. The behavior and genetic structure of species with large reproductive skew may be disproportionately impacted by anthropogenic actions affecting reproductively dominant individuals. Our results on age- and tactic-specific paternity success in male African elephants are the first from a free-ranging population and demonstrate that paternity success increases dramatically with age, with the small number of older bulls in the competitive state of musth being the most successful sires. However, nonmusth males sired 20% of genotyped calves, and 60% of mature bulls (> 20 years old) were estimated to have sired offspring during the 5-year study period. The 3 most successful males sired less than 20% of the genotyped offspring. Hence, contrary to prediction from behavior and life-history traits, reproduction was not heavily skewed compared with may other mammalian systems with a similar breeding system. Nevertheless, these results indicate that trophy hunting and ivory poaching, both of which target older bulls, may have substantial behavioral and genetic effects on elephant populations. In addition, these results are critical to the current debate on methods for managing and controlling increasing populations of this species

Performance differentiation: cutting losses and maximizing profits of private equity and venture capital investments

Recent research has pointed out the need to differentiate between good versus poor performance of venture capital and private equity investments and to analyze the factors that determine the ‘winners’ and ‘losers’ of a fund. This study examines the different contractual and behavioral characteristics and their influence on the positive and negative performances of private equity investments. Specifically, we analyze how fund managers apply tools and investment behavior to mitigate risks and maximize returns. The empirical investigation of these questions is based on a merged dataset, which combines the Venture Economics and CEPRES databases. It includes a total of 1,011 investments made by 137 different funds that belong to 54 private equity and venture capital firms worldwide over the period from 1979 to 2003. Our results confirm that the reduction of losses and the maximization of investment profits have different antecedents. Although losses are minimized by the use of convertibles and by increasing the venture capital firms’ accumulated experience, profits are increased by the potential of the fund’s management to allocate resources to portfolio companies. Our findings contribute to the understanding of the determinants of venture capital and private equity returns by differentiating between the mitigation of risks and the maximization of profits. Copyright Swiss Society for Financial Market Research 2007Private equity, Venture capital, Staging, Risk, Return, Performance, Profit, Losses, G24, E51,