1,721,000 research outputs found
Quantitative Genetics of Inbreeding in a Synthetic Maize Population
Full text linkThe average effects of inbreeding depression have been measured extensively in maize (Zea mays L.), but the influence of inbreeding on genetic variance has not been well studied. Two hundred random S1, S2, S3, and S4 lines were developed from the BS13(S)C0 population by single-seed descent and a set of 200 related half-sib families were developed from the S1 lines. The lines and half-sib families were evaluated in replicated yield trials for six agronomic characters. Under a purely additive model, the expected variance among inbred individuals is exactly twice the variance of noninbred individuals. The observed variance of inbred individuals in our study was 1.18 times the variance of noninbred individuals or less for five of six traits studied. By contrast, variance of dominance deviations of inbred individuals ranged from 1.6 to 3.3 times the variance of dominance deviations of noninbred individuals for five of six traits studied. A negative covariance between dominance deviations and breeding values in inbred individuals was found for all six traits. An estimator of the degree of dominance for arbitrary allele frequencies was developed. The estimated average degree of dominance in BS13(S)C0 ranged from 1.28 to 2.76, corresponding to overdominance or pseudo-overdominance. Our results suggested that some regions of linked genes have large effects on inbreeding depression in this population.This article is published as Edwards, Jode W., and Kendall R. Lamkey. "Quantitative genetics of inbreeding in a synthetic maize population." Crop science 42, no. 4 (2002): 1094-1104. doi: 10.2135/cropsci2002.1094. Posted with permission.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Observed and predicted phenotypic effects of inbreeding in the BS13(S)C0 maize population
No full textInbreeding occurs at both the individual level and the population level in most plant breeding programs. Modeling systems that include inbreeding requires knowledge of how inbreeding affects genetic variance. The objectives of this work were to model the effects of inbreeding on variances of genetic effects in individuals and repartitioning of genetic variance within and among subpopulations derived from a common metapopulation. Two hundred random inbred lines were developed in the BS13(S)C0 maize population by four generations of self-pollination to study the effects of inbreeding at the individual and population level in BS13(S)C0. The 200 lines along with a set of related half-sib families were evaluated in replicated yield trials. Genetic covariances of inbred relatives were estimated for six agronomic characters. Inbreeding caused a significant change in the mean of all six traits, and an increase in the variance of dominance deviations for five of six traits demonstrating that both the mean and variance of dominance deviations are larger in inbred individuals (F = 1) than in noninbred individuals. Additionally, dominance deviations became negatively correlated with breeding values in inbred individuals. The correlation between dominance deviations and genotypic values in inbred individuals was 0.37 or less for all traits except grain yield, which had a correlation between dominance deviations and genotypic values in inbred individuals of 0.63. The average degree of dominance was found to be greater than 2 (0 is no dominance, 1 is complete dominance) for all traits except grain yield. Based on predicted effects of inbreeding on variance component structure in BS13(S)C0, additive variance for grain yield will change very little at average inbreeding coefficients less than 0.5. Other traits will lose genetic variance roughly in accord with neutral additive expectations based on estimates of additive variance in the base population. Pseudo-overdominance, combined with the high correlation between inbred dominance deviations and genotypic values may explain the lack of response to inbred-progeny recurrent selection for grain yield in the BS13(S) population. Furthermore, our results predict that genetic variance will not be exhausted in this population, a result in accord with the observed long-term maintenance of genetic variance in recurrent selection programs in the Iowa Stiff Stalk Synthetic population.</p
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
