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Greater Variance (greater + variance)
Selected AbstractsINTERCOLONIAL VARIABILITY IN MACROMOLECULAR COMPOSITION IN P-STARVED AND P-REPLETE SCENEDESMUS POPULATIONS REVEALED BY INFRARED MICROSPECTROSCOPY,JOURNAL OF PHYCOLOGY, Issue 5 2008Philip Heraud Macromolecular variability in microalgal populations subject to different nutrient environments was investigated, using the chlorophyte alga Scenedesmus quadricauda (Turpin) Bréb. as a model organism. The large size of the four-cell coenobia in the strain used in this study (,35 ,m diameter) conveniently allowed high quality spectra to be obtained from individual coenobia using a laboratory-based Fourier transform infrared (FTIR) microscope with a conventional globar source of IR. By drawing sizable subpopulations of coenobia from two Scenedesmus cultures grown under either nutrient-replete or P-starved conditions, the population variability in macromolecular composition, and the effects of nutrient change upon this, could be estimated. On average, P-starved coenobia had higher carbohydrate and lower protein absorbance compared with P-replete coenobia. These parameters varied between coenobia with histograms of the ratio of absorbance of the largest protein and carbohydrate bands being Gaussian distributed. Distributions for the P-replete and P-starved subpopulations were nonoverlapping, with the difference in mean ratios for the two populations being statistically significant. Greater variance was observed in the P-starved subpopulation. In addition, multivariate models were developed using the spectral data, which could accurately predict the nutrient status of an independent individual coenobium, based on its FTIR spectrum. Partial least squares discriminant analysis (PLS-DA) was a better prediction method compared with soft independent modeling by class analogy (SIMCA). [source] Gender ratios for reading difficultiesDYSLEXIA, Issue 3 2009Jesse L. Hawke Abstract The prevalence of reading difficulties is typically higher in males than females in both referred and research-identified samples, and the ratio of males to females is greater in more affected samples. To explore possible gender differences in reading performance, we analysed data from 1133 twin pairs in which at least one member of each pair had a school history of reading problems and from 684 twin pairs from a comparison sample with no reading difficulties. Although the difference between the average scores of males and females in these two samples was very small, the variance of reading performance was significantly greater for males in both groups. We suggest that a greater variance of reading performance measures in males may account at least in part for their higher prevalence of reading difficulties as well as for the higher gender ratios that are observed in more severely impaired samples. Copyright © 2009 John Wiley & Sons, Ltd. [source] The impact of violations on uncertainty and the consequences for attractivenessHUMAN COMMUNICATION RESEARCH, Issue 2 2000WA Afifi This investigation aimed at extending past research on expectation violations by arguing that violations vary both in valance and in their influence on uncertainty and that the combination of valence and uncertainty states conjointly influences judgments of a violator's social attractiveness. In explaining the predicted variance in uncertainty following violations, a distinction is proposed between congruent violations (i.e., behaviors that are more intense instantiations of a previously displayed message) and incongruent violations (i.e., behaviors that are opposite in meaning from previously displayed messages). Five models for explaining violation effects are contrasted. Results (a) confirm that violations differ in their impact on uncertainty, (b) generally support the validity of the proposed distinction between congruent and incongruent violations, and show that the inclusion of uncertainty and valence in models of violation outcomes accounts for greater variance in social attraction than either one separately. [source] Constellations and careers: toward understanding the effects of multiple developmental relationshipsJOURNAL OF ORGANIZATIONAL BEHAVIOR, Issue 3 2001Monica C. Higgins This paper examines the effects of individuals' primary and multiple developmental relationships in a longitudinal study of the careers of lawyers. By juxtaposing the effects of the primary developmental relationship with those of individuals' sets or ,constellations' of developmental relationships, the present study lends insight into if and when these two perspectives on mentoring yield different results regarding the effects of mentoring on protégé career outcomes. The findings from the present study show that while the quality of one's primary developer affects short-term career outcomes such as work satisfaction and intentions to remain with one's firm, it is the composition and quality of an individual's entire constellation of developmental relationships that account for long-run protégé career outcomes such as organizational retention and promotion. Further, results from the present study provide evidence that the constellation perspective explains greater variance with respect to protégé career outcomes than does the primary or more traditional perspective on mentoring. Implications for research on mentoring, developmental relationships, and careers are discussed. Copyright © 2001 John Wiley & Sons, Ltd. [source] ASSESSING THE INCREMENTAL VALIDITY OF TEAM CONSENSUS RATINGS OVER AGGREGATION OF INDIVIDUAL-LEVEL DATA IN PREDICTING TEAM EFFECTIVENESSPERSONNEL PSYCHOLOGY, Issue 3 2001BRADLEY L. KIRKMAN Using data collected from 98 work teams, empowerment levels were assessed based on the aggregation of individual team member ratings as well as on a team consensus approach utilized after aggregation. These 2 methods of measuring team empowerment were then compared on their ability to predict manager ratings of team effectiveness on 4 dimensions. Findings demonstrated that the consensus method of measuring team empowerment explained significantly greater variance in team effectiveness than did the aggregation method alone. We discuss implications for team research and practice based on these findings and include a discussion on when using consensus after aggregation may be most appropriate. [source] Estimating the Lagging Error in Real Estate Price IndicesREAL ESTATE ECONOMICS, Issue 1 2003Yuming Fu Real estate indices based on appraisals or sale prices of properties are known for their slow response to market news. These indices can therefore be represented (in logarithm) as the sum of a latent "true" price index and a lagging error. We show that the latent appreciation return and the lagging error can be jointly estimated in a state,space model, which has two key features. First, it employs exogenous variables known to predict asset returns to predict the latent appreciation return. Second, it incorporates known sources of the lagging error, such as the partial adjustment in observed index to the latent appreciation return and the seasonality in reappraisal quality. We find that, after the estimated lagging errors are removed, the appraisal,based National Council of Real Estate Investment Fiduciaries returns become more informative and hence exhibit (i) greater variance, (ii) weaker auto correlation, (iii) higher correlation with the returns of the securitized real estate and (iv) more timely response to market news. [source] Hatching asynchrony and growth trade-offs within domesticated and wild zebra finch, Taeniopygia guttata, broodsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2010MARK C. MAINWARING The Australian zebra finch, Taeniopygia guttata, is a widely used model organism, yet few studies have compared domesticated and wild birds with the aim of examining its relevance as an evolutionary model species. Domestic and wild broods hatch over approximately 4 and 2 days, respectively, which is important given that nestlings can fledge after as little as 12 days, although 16,18 days is common. We aimed to evaluate the extent to which the greater hatching asynchrony in domestic stock may effect reproductive success through greater variance in size hierarchies, variance in within-brood growth rates, and partial brood mortality. Therefore, by simultaneously controlling brood sizes and experimentally manipulating hatching intervals in both domesticated and wild birds, we investigated the consequences of hatching intervals for fledging success and nestling growth patterns, as well as trade-offs. Fledging success was similarly high in domestic and wild broods of either hatching pattern. Nonetheless, between-brood analyses revealed that domestic nestlings had significantly higher masses, larger skeletal characters, and longer wings than their wild counterparts, although wild nestlings had comparable wing lengths at the pre-fledging stage. Moreover, within-brood analyses revealed only negligible differences between domestic and wild nestlings, and larger effects of hatching order and hatching pattern. Therefore, despite significant differences in the hatching intervals, and the ultimate size achieved by nestlings, the domestication process does not appear to have significantly altered nestling growth trade-offs. The present study provides reassuring evidence that studies involving domesticated zebra finches, or other domesticated model organisms, may provide reasonable adaptive explanations in behavioural and evolutionary ecology. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 763,773. [source] A REAPPRAISAL OF BATEMAN'S CLASSIC STUDY OF INTRASEXUAL SELECTIONEVOLUTION, Issue 11 2007Brian F. Snyder Bateman's (1948) study showing greater variances in number of mates and reproductive success in male than female Drosophila melanogaster is a foundational paper in sexual selection. Here we show for the first time that his methods had flaws, including the elimination of genetic variance, sampling biases, miscalculations of fitness variances, statistical pseudo-replication, and selective presentation of data. We conclude that Bateman's results are unreliable, his conclusions are questionable, and his observed variances are similar to those expected under random mating. Despite our analysis, we do not intend this article as a criticism of Bateman; he accomplished his work without modern computational tools, and his approach was groundbreaking emphasizing the significance of fitness variance for sexual selection. However, this reanalysis has implications for what counts as evidence for sexual selection and we believe that our concerns should be of interest to contemporary students of sexual selection. We call for repetitions of Bateman's study using modern statistical and molecular methods. [source] | ||||||||||||||||