نتایج جستجو برای: estimated variance

تعداد نتایج: 364794  

Journal: :Journal of dairy science 2000
C P Van Tassell I Misztal L Varona

Fractions of variance accounted for by additive genetic, dominance genetic, and permanent environmental effects for milk, fat, and protein yields; somatic cell score; and productive life were estimated from Holstein data used for national genetic evaluations. Contemporary group assignments were determined using the national procedure. Data included 1,973,317 milk and fat records for 812,659 cow...

Journal: :پژوهش در نشخوارکنندگان 0
خبات خیرآبادی دانشجوی ارشد صادق علیجانی هیات علمی دانشگاه تبرزی سید عباس رأفت عضو هیات علمی دانشگاه تبریز غلامعلی مقدم عضو هیات علمی دانشگاه تبریز

abstract             (co) variance components of milk, fat and protein yield of 11368 first lactation iranian holstein dairy cow were estimated by single trait random regression test-day models and restricted maximum likelihood (reml) method. in this study the homogeneous residual variance was assumed throughout lactation. estimated heritability for 305-day production traits ranged from 0.25 to...

Journal: :Genetics 1991
A Ruiz M Santos A Barbadilla J E Quezada-Díaz E Hasson A Fontdevila

Previous work has shown thorax length to be under directional selection in the Drosophila buzzatii population of Carboneras. In order to predict the genetic consequences of natural selection, genetic variation for this trait was investigated in two ways. First, narrow sense heritability was estimated in the laboratory F2 generation of a sample of wild flies by means of the offspring-parent regr...

Journal: :علوم دامی 0
علی اکبر قره داغی استادیار ، موسسه تحقیقات علوم دامی کشور شعله قربانی مربی، موسسه تحقیقات علوم دامی کشور محمدعلی کمالی استادیار ، سازمان تحقیقات، آموزش و ترویج کشاورزی مختارعلی عباسی دانشیار، موسسه تحقیقات علوم دامی کشور

the data of this study were collected by indigenous chicken breeding centers in the west azerbaijan for 11 generations. the (co) variance components, heritability's, correlations between traits and breeding values were estimated by multi-trait animal model using wombat software. the genetic trends of traits over 11 generations of selection, using average function of breeding values per gen...

2015
Youngdoe Kim Young Lee Sungyoung Lee Nam Hee Kim Jeongmin Lim Young Jin Kim Ji Hee Oh Haesook Min Meehee Lee Hyeon-Jeong Seo So-Hyun Lee Joohon Sung Nam H. Cho Bong-Jo Kim Bok-Ghee Han Robert C. Elston Sungho Won Juyoung Lee

For a family-based sample, the phenotypic variance-covariance matrix can be parameterized to include the variance of a polygenic effect that has then been estimated using a variance component analysis. However, with the advent of large-scale genomic data, the genetic relationship matrix (GRM) can be estimated and can be utilized to parameterize the variance of a polygenic effect for population-...

2004
Ye Tong Robert L. Brennan

The estimation of standard errors of estimated variance components has long been a challenging task in generalizability theory. For two decades researchers have speculated about the potential applicability of the bootstrap for obtaining such estimates, but the same researchers have identified problems in using the bootstrap. Some of these problems are associated with the fact that bootstrap pro...

Journal: :Vital and health statistics. Series 2, Data evaluation and methods research 1967
C L Chiang

Journal: :Magnetic resonance in medicine 2007
Lin-Ching Chang Cheng Guan Koay Carlo Pierpaoli Peter J Basser

In typical applications of diffusion tensor imaging (DTI), DT-derived quantities are used to make a diagnostic, therapeutic, or scientific determination. In such cases it is essential to characterize the variability of these tensor-derived quantities. Parametric and empirical methods have been proposed to estimate the variance of the estimated DT, and quantities derived from it. However, the fo...

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