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| Melhim, Almuhanad; O'Donoghue, Erik J.; Shumway, C. Richard. |
| Recent consolidation in agriculture has shifted production toward fewer but larger farms, reshaping business relationships between farmers, processors, input suppliers, and local communities. We analyze growth and diversification of U.S. corn, wheat, apple, and beef farms by examining longitudinal changes in 10 size cohorts through three successive censuses. We fail to reject Gibrat’s law in apple and wheat industries and the mean reversion hypothesis in beef and corn industries. Apple and wheat farms diversify over time. The findings suggest that scale economies diminish for large farms across all four industries and scope economies dominate scale economies for large apple and wheat farms. |
| Tipo: Journal Article |
Palavras-chave: Diversification; Firm growth; Gibrat’s law; Longitudinal data; Scale economies; Scope economies; Agribusiness; Farm Management; Production Economics; Q12. |
| Ano: 2009 |
URL: http://purl.umn.edu/48757 |
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| Silva,Fabyano Fonseca e; Zambrano,Maria Fernanda Betancur; Varona,Luis; Glória,Leonardo Siqueira; Lopes,Paulo Sávio; Silva,Marcos Vinícius Gualberto Barbosa; Arbex,Wagner; Lázaro,Sirlene Fernandes; Resende,Marcos Deon Vilela de; Guimarães,Simone Eliza Facioni. |
| ABSTRACT: Genome association analyses have been successful in identifying quantitative trait loci (QTLs) for pig body weights measured at a single age. However, when considering the whole weight trajectories over time in the context of genome association analyses, it is important to look at the markers that affect growth curve parameters. The easiest way to consider them is via the two-step method, in which the growth curve parameters and marker effects are estimated separately, thereby resulting in a reduction of the statistical power and the precision of estimates. One efficient solution is to adopt nonlinear mixed models (NMM), which enables a joint modeling of the individual growth curves and marker effects. Our aim was to propose a genome association... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: SNP markers; Body weight; Longitudinal data. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162017000100001 |
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| Macedo,Osmar Jesus; Barbin,Décio; Mourão,Gerson Barreto. |
| Covariance functions and random regression models have been considered as an alternative for data adjustment, in sequence, stemming from the same animal along time and which presents a structured pattern of covariance. Aiming to evaluate the performance of random regression models based on the Legendre, modified Jacobi and trigonometric functions, data concerning the weights of Nellore breed animals were used from birth to the 800th day of life, in models that assumed direct additive and animal permanent environmental effects coefficients. The Schwarz Bayesian information criterion (BIC) led to the selection of the models Legendre of order six (ML6), Jacobi of order five (MJ5) and trigonometric of order six (MT6), the ML6 model presenting the lowest BIC.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Additive variance; Heritability; Jacobi; Legendre; Longitudinal data. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162009000400014 |
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