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 | Acesso ao texto completo restrito à biblioteca da Embrapa Caprinos e Ovinos. Para informações adicionais entre em contato com cnpc.biblioteca@embrapa.br. |
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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
03/04/1996 |
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Data da última atualização: |
29/11/2023 |
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Autoria: |
SWIGER, L. A.; HARVEY, W. R.; EVERSON, D. O.; GREGORY, K. E. |
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Título: |
The variance of intraclass correlation involving crous with one observation. |
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Ano de publicação: |
1964 |
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Fonte/Imprenta: |
Biometrics, v. 20, p. 818-826, 1964. |
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Idioma: |
Inglês |
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Conteúdo: |
Abstract; An approximate formula is derived for the variance of intraclass correlation when unequal numbers of observations per group occur. The effect on the variance of t of adding groups with single observations is examined using the formula and results obtained by empirically generating data on a computer. The empirical results indicate that the approximate formula is satisfactory over the range of numbers used. Adding a group with fewer than the average number of observations per group tends to reduce Vt by increasing the degrees of freedom for groups by one, but tends to increase Vt by decreasing the average precision of estimating group means. The net effect can be either negative or positive, depending on t, s and the ni’s. Robertson [1962] pointed out that, when the ratio of the between group mean square to the within group mean square is small, exclusion of groups below half the average size will reduce the variance of the between group component. He further suggested a method for combining estimates of the between group component when n is highly variable. Results using the formula show that the point where efficiency is lost when a group of size one is added is primarily a function of the number per group, and is affected very little by the number of groups. The value of n where groups of size one should be excluded is shown graphically for varying levels of t. Increases in Vt are demonstrated using the empirical data. The empirical results suggest that the increase in V t may be even larger than the formula indicates, especially for large values of t. Only the addition of groups of size one is studied. Adding small groups larger than one would also tend to increase Vtwhen n and t are small. MenosAbstract; An approximate formula is derived for the variance of intraclass correlation when unequal numbers of observations per group occur. The effect on the variance of t of adding groups with single observations is examined using the formula and results obtained by empirically generating data on a computer. The empirical results indicate that the approximate formula is satisfactory over the range of numbers used. Adding a group with fewer than the average number of observations per group tends to reduce Vt by increasing the degrees of freedom for groups by one, but tends to increase Vt by decreasing the average precision of estimating group means. The net effect can be either negative or positive, depending on t, s and the ni’s. Robertson [1962] pointed out that, when the ratio of the between group mean square to the within group mean square is small, exclusion of groups below half the average size will reduce the variance of the between group component. He further suggested a method for combining estimates of the between group component when n is highly variable. Results using the formula show that the point where efficiency is lost when a group of size one is added is primarily a function of the number per group, and is affected very little by the number of groups. The value of n where groups of size one should be excluded is shown graphically for varying levels of t. Increases in Vt are demonstrated using the empirical data. The empirical results suggest that the incre... Mostrar Tudo |
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Palavras-Chave: |
Herdabilidade; Melhoramento genetico. |
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Thesagro: |
Animal. |
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Thesaurus Nal: |
Genetic correlation; Genetic improvement; Heritability. |
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Categoria do assunto: |
G Melhoramento Genético |
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Marc: |
LEADER 02377naa a2200229 a 4500
001 1519899
005 2023-11-29
008 1964 bl uuuu u00u1 u #d
100 1 $aSWIGER, L. A.
245 $aThe variance of intraclass correlation involving crous with one observation.$h[electronic resource]
260 $c1964
520 $aAbstract; An approximate formula is derived for the variance of intraclass correlation when unequal numbers of observations per group occur. The effect on the variance of t of adding groups with single observations is examined using the formula and results obtained by empirically generating data on a computer. The empirical results indicate that the approximate formula is satisfactory over the range of numbers used. Adding a group with fewer than the average number of observations per group tends to reduce Vt by increasing the degrees of freedom for groups by one, but tends to increase Vt by decreasing the average precision of estimating group means. The net effect can be either negative or positive, depending on t, s and the ni’s. Robertson [1962] pointed out that, when the ratio of the between group mean square to the within group mean square is small, exclusion of groups below half the average size will reduce the variance of the between group component. He further suggested a method for combining estimates of the between group component when n is highly variable. Results using the formula show that the point where efficiency is lost when a group of size one is added is primarily a function of the number per group, and is affected very little by the number of groups. The value of n where groups of size one should be excluded is shown graphically for varying levels of t. Increases in Vt are demonstrated using the empirical data. The empirical results suggest that the increase in V t may be even larger than the formula indicates, especially for large values of t. Only the addition of groups of size one is studied. Adding small groups larger than one would also tend to increase Vtwhen n and t are small.
650 $aGenetic correlation
650 $aGenetic improvement
650 $aHeritability
650 $aAnimal
653 $aHerdabilidade
653 $aMelhoramento genetico
700 1 $aHARVEY, W. R.
700 1 $aEVERSON, D. O.
700 1 $aGREGORY, K. E.
773 $tBiometrics$gv. 20, p. 818-826, 1964.
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Embrapa Caprinos e Ovinos (CNPC) |
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Biblioteca(s): |
Embrapa Amazônia Oriental. |
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Data corrente: |
30/11/2023 |
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Data da última atualização: |
30/11/2023 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Circulação/Nível: |
A - 1 |
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Autoria: |
CAMARGO JÚNIOR, R. N. C.; ARAÚJO, C. V. de; SILVA, W. C. da; ARAÚJO, S. I. de; LÔBO, R. B.; NAKABASHI, L. R. M.; CASTRO, L. M. de; MENEZES, F. L.; SILVA, A. G. M. e; SILVA, L. K. X.; SILVA, J. A. R. da; BARBOSA, A. V. C.; MARQUES, J. R. F.; LOURENÇO JÚNIOR, J. de. |
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Afiliação: |
RAIMUNDO NONATO COLARES CAMARGO JÚNIOR, UNIVERSIDADE FEDERAL DO PARÁ; CLÁUDIO VIEIRA DE ARAÚJO, UNIVERSIDADE FEDERAL DO MATO GROSSO; WELLIGTON CONCEIÇÃO DA SILVA, UNIVERSIDADE FEDERAL DO PARÁ; SIMONE INOE DE ARAÚJO, UNIVERSIDADE FEDERAL DE MATO GROSSO; RAYSILDO BARBOSA LÔBO, ASSOCIAÇÃO NACIONAL DE CRIADORES E PESQUISADORES; LÍLIAN ROBERTA MATIMOTO NAKABASHI, ASSOCIAÇÃO NACIONAL DE CRIADORES E PESQUISADORES; LETÍCIA MENDES DE CASTRO, ASSOCIAÇÃO NACIONAL DE CRIADORES E PESQUISADORES; FLÁVIO LUIZ MENEZES, UNIVERSIDADE FEDERAL DO MATO GROSSO; ANDRÉ GUIMARÃES MACIEL E SILVA, UNIVERSIDADE FEDERAL DO PARÁ; LÍLIAN KÁTIA XIMENES SILVA, UNIVERSIDADE FEDERAL DO PARÁ; JAMILE ANDRÉA RODRIGUES DA SILVA, UNIVERSIDADE FEDERAL RURAL DA AMAZÔNIA; ANTÔNIO VINICIUS CORREA BARBOSA, UNIVERSIDADE FEDERAL RURAL DA AMAZÔNIA; JOSE RIBAMAR FELIPE MARQUES, CPATU; JOSÉ DE BRITO LOURENÇO JÚNIOR, UNIVERSIDADE FEDERAL DO PARÁ. |
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Título: |
Mixed models in nonlinear regression for description of the growth of Nelore Cattle. |
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Ano de publicação: |
2023 |
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Fonte/Imprenta: |
Animals, v. 13, n. 1, Article 101, 2023. |
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DOI: |
https://doi.org/10.3390/ani13010101 |
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Idioma: |
Inglês |
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Conteúdo: |
Body weight records were used to characterize the growth curve of Nelore cattle. Body weight was regressed as a function of age, for both sexes, by using nonlinear models through the functions of Brody, Gompertz, Logistic, Richards, Meloun 1, Von Bertalanffy, and Von Bertalanffy. The quality of the model arrangements was evaluated by employing Akaike and Bayesian Schwarz information criteria. The Brody function provided the best adaptations by the evaluators and, considering the asymptotic weight and the maturation rate as random, a reduction in residual variance of 79% for males and 83% for females was obtained in relation to the models under fixed contexts. In males, the absolute and relative growth rates ranged from 0.921 to 0.261 kg/day and 2.39 to 0.08%, respectively. For the same rates, under another approach, females ranged from 0.922 to 0.198 kg/day and 2.55 to 0.06%, respectively. Males showed greater growth acceleration at the beginning of the growth trajectory, being equal to females at 397 days of age and from that age onward they presented lower estimates. The nonlinear regression model approach under the mixed-models context allows reduction of residual variance, increasing model accuracy. |
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Palavras-Chave: |
Regressão não-linear. |
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Thesagro: |
Crescimento; Gado; Gado Nelore. |
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Categoria do assunto: |
L Ciência Animal e Produtos de Origem Animal |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/doc/1158952/1/Mixed-Models.pdf
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Marc: |
LEADER 02217naa a2200337 a 4500
001 2158952
005 2023-11-30
008 2023 bl uuuu u00u1 u #d
024 7 $ahttps://doi.org/10.3390/ani13010101$2DOI
100 1 $aCAMARGO JÚNIOR, R. N. C.
245 $aMixed models in nonlinear regression for description of the growth of Nelore Cattle.$h[electronic resource]
260 $c2023
520 $aBody weight records were used to characterize the growth curve of Nelore cattle. Body weight was regressed as a function of age, for both sexes, by using nonlinear models through the functions of Brody, Gompertz, Logistic, Richards, Meloun 1, Von Bertalanffy, and Von Bertalanffy. The quality of the model arrangements was evaluated by employing Akaike and Bayesian Schwarz information criteria. The Brody function provided the best adaptations by the evaluators and, considering the asymptotic weight and the maturation rate as random, a reduction in residual variance of 79% for males and 83% for females was obtained in relation to the models under fixed contexts. In males, the absolute and relative growth rates ranged from 0.921 to 0.261 kg/day and 2.39 to 0.08%, respectively. For the same rates, under another approach, females ranged from 0.922 to 0.198 kg/day and 2.55 to 0.06%, respectively. Males showed greater growth acceleration at the beginning of the growth trajectory, being equal to females at 397 days of age and from that age onward they presented lower estimates. The nonlinear regression model approach under the mixed-models context allows reduction of residual variance, increasing model accuracy.
650 $aCrescimento
650 $aGado
650 $aGado Nelore
653 $aRegressão não-linear
700 1 $aARAÚJO, C. V. de
700 1 $aSILVA, W. C. da
700 1 $aARAÚJO, S. I. de
700 1 $aLÔBO, R. B.
700 1 $aNAKABASHI, L. R. M.
700 1 $aCASTRO, L. M. de
700 1 $aMENEZES, F. L.
700 1 $aSILVA, A. G. M. e
700 1 $aSILVA, L. K. X.
700 1 $aSILVA, J. A. R. da
700 1 $aBARBOSA, A. V. C.
700 1 $aMARQUES, J. R. F.
700 1 $aLOURENÇO JÚNIOR, J. de
773 $tAnimals$gv. 13, n. 1, Article 101, 2023.
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