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This paper explores the way in which some lesbians rely on culturally circulated narratives about identity to assess safer sex and their potential risk of sexually transmitted infection (STI) and HIV. A well-established narrative within the literature about lesbian safer sex is that STI risk is non-existent. The implications of this are important because they demonstrate the perception of lesbian identity and notions of safety. This study focuses on how gender and sexuality contextualise an assessment of risk and safety for lesbians. This is vital to understand because there is still a lack of language about lesbian safer sex practices and techniques. Lesbians narrate their assessments of STI and HIV risk through the lenses of gender and sexuality – locating 'risk' in gay men and bisexual women. Using narrative analysis, I find that lesbians assess their risk by constructing characters from culturally circulated narratives steeped in homophobia and biphobia of the sensible lesbian, the risky gay man and the uncertain bisexual. [ABSTRACT FROM AUTHOR]

Ten outstanding and 10 average teachers of the gifted were interviewed. Outstanding teachers, identified by a panel of experts, differed from average teachers on several critical competencies, including: enthusiasm, self-confidence, being a facilitator, being able to apply knowledge, having a strong achievement orientation, building program support for gifted education, etc. (Author/JDD)

Research has been conducted on adaptive evolution.The authors have investigated different types of Drosophila melanogaster lines varying in their level of genetic recombination, and the results demonstrate that recombination has not accelerated adaptation during fluctuating or directional selection for geotaxis.

Stress is generally thought to increase the strength of selection, although empirical results are mixed and general conclusions are difficult because data are limited. Here we compare the fitness effects of nine independent recessive mutations in Drosophila melanogaster in a high- and low-dietary-stress environment, estimating the strength of selection on these mutations arising from both a competitive measure of male reproductive success and productivity (female fecundity and the subsequent survival to adulthood of her offspring). The effect of stress on male reproductive success has not been addressed previously for individual loci and is of particular interest with respect to the alignment of natural and sexual selection. Our results do not support the hypothesis that stress increases the efficacy of selection arising from either fitness component. Results concerning the alignment of natural and sexual selection were mixed, although data are limited. In the low-stress environment, selection on mating success and productivity were concordant for five of nine mutations (four out of four when restricted to those with significant or near-significant productivity effects), whereas in the high-stress environment, selection aligned for seven of nine mutations (two out of two when restricted to those having significant productivity effects). General conclusions as to the effects of stress on the strength of selection and the alignment of natural and sexual selection await data from additional mutations, fitness components and stressors. [ABSTRACT FROM AUTHOR]

Electrical power usage contributes significantly to the operational costs of large computer systems. At the Hypersonic Missile Technology Research and Operations Center (HMT-ROC) our system usage patterns provide a significant opportunity to reduce operating costs since there are a small number of dedicated users. The relatively predictable nature of our usage patterns allows for the scheduling of computational resource availability. We take advantage of this predictability to shut down systems during periods of low usage to reduce power consumption. With interconnected computer cluster systems, reducing the number of online nodes is more than a simple matter of throwing the power switch on a portion of the cluster. The paper discusses these issues and an approach for power reduction strategies for a computational system with a heterogeneous system mix that includes a large (1560-node) Apple Xserve PowerPC supercluster. In practice, the average load on computer systems may be much less than the peak load although the infrastructure supporting the operation of large computer systems in a computer or data center must still be designed with the peak loads in mind. Given that a significant portion of the time, systems loads can be less than full peak, an opportunity exists for cost savings if idle systems can be dynamically throttled back, slept, or shut off entirely. The paper describes two separate strategies that meet the requirements for both power conservation and system availability at HMT-ROC. The first approach, for legacy systems, is not much more than a brute force approach to power management which we call Time-Driven System Management (TDSM). The second approach, which we call Dynamic-Loading System Management (DLSM), is applicable to more current systems with ‘Wake-on-LAN’ capability and takes a more granular approach to the management of system resources. The paper details the rule sets that we have developed and implemented in the two approaches to system power management and discusses some results with these approaches. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Accumulation of deleterious mutations has important consequences for the evolution of mating systems and the persistence of small populations. It is well established that consanguineous mating can purge a part of the mutation load and that lethal mutations can also be purged in small populations. However, the efficiency of purging in natural populations, due to either consanguineous mating or to reduced population size, has been questioned. Consequences of consanguineous mating systems and small population size are often equated under "inbreeding" because both increase homozygosity, and selection is though to be more efficient against homozygous deleterious alleles. I show that two processes of purging that I call "purging by drift" and "purging by nonrandom mating" have to be distinguished. Conditions under which the two ways of purging are effective are derived. Nonrandom mating can purge deleterious mutations regardless of their dominance level, whereas only highly recessive mutations can be purged by drift. Both types of purging are limited by population size, and sharp thresholds separate domains where purging is either effective or not. The limitations derived here on the efficiency of purging are compatible with some experimental studies. Implications of these results for conservation and evolution of mating systems are discussed. [ABSTRACT FROM AUTHOR]

Theory predicts a significant relationship between the size of a population and the magnitude and composition of its genetic load, but few natural populations have been investigated. We examined the magnitude of genetic load due to recessive deleterious alleles (GL) both segregating and fixed within Gentianella germanica populations of varying size by selfing and reciprocally crossing plants within and between natural populations according to a partial diallel design and by comparing the performance of the experimental progeny in a common-garden experiment. The results show that GL for total fitness in small populations (fewer than 200 plants) was mainly due to fixed recessive deleterious alleles, whereas GL for total fitness in larger populations (more than 200 plants) appeared to be mainly due to segregating deleterious recessive alleles. The total fitness of selfed plants increased with decreasing population size, indicating some purging of deleterious alleles associated with declining population sizes. The magnitudes of GL due to fixed deleterious alleles in small populations and segregating deleterious alleles in large populations, however, were overall similar, suggesting that purging selection was an insignificant force when compared to genetic drift in determining the magnitude of GL in small natural populations in this species. The results of this study highlight the importance of population size in determining the dynamics of genetic loads of natural populations and are overall in line with a large body of theoretical work indicating that small populations may face higher extinction risks due to the fixation and accumulation of deleterious alleles of small effect. [ABSTRACT FROM AUTHOR]

Presents a study which examined the effects of metapopulation processes on several different aspects of population genetics. Methods; Results and discussion; Implications for empirical studies.

Presents information on a study which considered the forces that may play a role in the adaptive evolution of premating isolation, direct selection on preferences and indirect selection against postmating, prezygotic incompatibilities. Mechanisms that may cause direct selection on preferences during speciation; Mechanisms that cause premating isolation evolution above and beyond traditional reinforcement.

Describes the stochastic hybrid accumulation of Dobzhansky-Muller incompatibilities as a function of time. Cases of compatibility speciation; Effects of genomic compartmentalization; Evolution of postzygotic isolation.

Discusses a study which contrasted two ways of representing the data in a phylogenetic tree. Comparison of the Poisson process approach and the survival analysis approach; Birth-death process models; Factors that affect apparent trends in diversification.