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Experimental Contexts (experimental + context)
Selected AbstractsREVIEW: Optimality models in the age of experimental evolution and genomicsJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 9 2010J. J. BULL Abstract Optimality models have been used to predict evolution of many properties of organisms. They typically neglect genetic details, whether by necessity or design. This omission is a common source of criticism, and although this limitation of optimality is widely acknowledged, it has mostly been defended rather than evaluated for its impact. Experimental adaptation of model organisms provides a new arena for testing optimality models and for simultaneously integrating genetics. First, an experimental context with a well-researched organism allows dissection of the evolutionary process to identify causes of model failure , whether the model is wrong about genetics or selection. Second, optimality models provide a meaningful context for the process and mechanics of evolution, and thus may be used to elicit realistic genetic bases of adaptation , an especially useful augmentation to well-researched genetic systems. A few studies of microbes have begun to pioneer this new direction. Incompatibility between the assumed and actual genetics has been demonstrated to be the cause of model failure in some cases. More interestingly, evolution at the phenotypic level has sometimes matched prediction even though the adaptive mutations defy mechanisms established by decades of classic genetic studies. Integration of experimental evolutionary tests with genetics heralds a new wave for optimality models and their extensions that does not merely emphasize the forces driving evolution. [source] Using historical data for Bayesian sample size determinationJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 1 2007Fulvio De Santis Summary., We consider the sample size determination (SSD) problem, which is a basic yet extremely important aspect of experimental design. Specifically, we deal with the Bayesian approach to SSD, which gives researchers the possibility of taking into account pre-experimental information and uncertainty on unknown parameters. At the design stage, this fact offers the advantage of removing or mitigating typical drawbacks of classical methods, which might lead to serious miscalculation of the sample size. In this context, the leading idea is to choose the minimal sample size that guarantees a probabilistic control on the performance of quantities that are derived from the posterior distribution and used for inference on parameters of interest. We are concerned with the use of historical data,i.e. observations from previous similar studies,for SSD. We illustrate how the class of power priors can be fruitfully employed to deal with lack of homogeneity between historical data and observations of the upcoming experiment. This problem, in fact, determines the necessity of discounting prior information and of evaluating the effect of heterogeneity on the optimal sample size. Some of the most popular Bayesian SSD methods are reviewed and their use, in concert with power priors, is illustrated in several medical experimental contexts. [source] Context-specific mate choice criteria: Women's trade-offs in the contexts of long-term and extra-pair mateshipsPERSONAL RELATIONSHIPS, Issue 4 2001JOANNA E. SCHEIB Women's mate choice criteria were examined experimentally in the contexts of long-term and extra-pair mateship scenarios. In long-term mateships, women may benefit by pairing with males who provide material resources and assistance in child rearing. In contrast, in extra-pair mateships, women may benefit in other ways, with such benefits outweighing the potential costs imposed by a primary mate who discovers the relationship. One benefit, or evolutionary function, of extra-pair mateships may be to replace a primary mate, in which case mate preferences should look similar across long-term and extra-pair contexts. However, another function of extra-pair mateships may be to obtain high quality gametes (Le., "good genes"), in which case women should be differentially attracted to cues of heritable phenotypic quality, such as physical attractiveness. By using detailed verbal and pictorial descriptions of men and requiring participants to trade off physical attractiveness for good character (i.e., being a good cooperator and parent), it was possible to determine whether women's criteria for partners varied across experimental contexts. Findings suggest that extra-pair mateships may have served the evolutionary function of obtaining "good genes," because attractiveness was more important in extra-pair mateships to the detriment of good character. This effect was maintained even when characteristics of the female participants (age, parity, marital experience) were covaried. In addition, the preference for physical attractiveness was specific to the sexual context; it did not generalize, in a second experiment, to choices among short-term male coworkers. [source] Copula duration and sperm storage in Mediterranean fruit flies from a wild populationPHYSIOLOGICAL ENTOMOLOGY, Issue 1 2000P.H.illip W. Taylor Summary In the Mediterranean fruit fly (Ceratitis capitata Weidemann, ,medfly'), a lekking tephritid, evidence from laboratory studies of flies from laboratory strains suggests that copulation is shorter, and sperm storage more abundant, if males are large or protein-fed, and that copulation is longer when females are large. In addition, sperm tend to be stored asymmetrically between the female's two spermathecae and this asymmetry declines with abundance of stored sperm. The primary objective of this study was to investigate whether these trends persist in other experimental contexts that bear closer resemblance to nature. Accordingly, we carried out experiments in a field-cage using males derived as adults from a wild population and virgin females reared from naturally infested fruit. The results of this study were consistent with laboratory studies in that copula duration increased with female size, that sperm were stored asymmetrically between the females' spermathecae, and that this asymmetry declined with number of sperm stored. However, we also found some previously unreported effects of female size; large females stored more sperm and stored sperm more asymmetrically between their two spermathecae than did small females. Unlike the laboratory studies, copula duration and sperm storage patterns were unaffected by male size and diet. This may be due to overwhelming variation from other sources in the wild-collected males used, as well as environmental variability in the semi-natural setting. [source] Gesturing Saves Cognitive Resources When Talking About Nonpresent ObjectsCOGNITIVE SCIENCE - A MULTIDISCIPLINARY JOURNAL, Issue 4 2010Raedy Ping Abstract In numerous experimental contexts, gesturing has been shown to lighten a speaker's cognitive load. However, in all of these experimental paradigms, the gestures have been directed to items in the "here-and-now." This study attempts to generalize gesture's ability to lighten cognitive load. We demonstrate here that gesturing continues to confer cognitive benefits when speakers talk about objects that are not present, and therefore cannot be directly indexed by gesture. These findings suggest that gesturing confers its benefits by more than simply tying abstract speech to the objects directly visible in the environment. Moreover, we show that the cognitive benefit conferred by gesturing is greater when novice learners produce gestures that add to the information expressed in speech than when they produce gestures that convey the same information as speech, suggesting that it is gesture's meaningfulness that gives it the ability to affect working memory load. [source] | |||||||||||||