The impact of reducing the frequency of animals genotyped at higher density on imputation and prediction accuracies using ssGBLUP1.

The largest gains in accuracy in a genomic selection program come from genotyping young selection candidates who have not yet produced progeny and who might, or might not, have a phenotypic record recorded. To reduce genotyping costs and to allow for an increased amount of genomic data to be available in a population, young selection candidates may be genotyped with low-density (LD) panels and imputed to a higher density. However, to ensure that a reasonable imputation accuracy persists overtime, some parent animals originally genotyped at LD must be re-genotyped at a higher density. This study investigated the long-term impact of selectively re-genotyping parents with a medium-density (MD) SNP panel on the accuracy of imputation and on the genetic predictions using ssGBLUP in a simulated beef cattle population. Assuming a moderately heritable trait (0.25) and a population undergoing selection, the simulation generated sequence data for a founder population (100 male and 500 female individuals) and 9,000 neutral markers, considered as the MD panel. All selection candidates from generation 8 to 15 were genotyped with LD panels corresponding to a density of 0.5% (LD_0.5), 2% (LD_2), and 5% (LD_5) of the MD. Re-genotyping scenarios chose parents at random or based on EBV and ranged from 10% of male parents to re-genotyping all male and female parents with MD. Ranges in average imputation accuracy at generation 15 were 0.567 to 0.936, 0.795 to 0.985, and 0.931 to 0.995 for the LD_0.5, LD_2, and LD_5, respectively, and the average EBV accuracies ranged from 0.453 to 0.735, 0.631 to 0.784, and 0.748 to 0.807 for LD_0.5, LD_2, and LD_5, respectively. Re-genotyping parents based on their EBV resulted in higher imputation and EBV accuracies compared to selecting parents at random and these values increased with the size of LD panels. Differences between re-genotyping scenarios decreased when the density of the LD panel increased, suggesting fewer animals needed to be re-genotyped to achieve higher accuracies. In general, imputation and EBV accuracies were greater when more parents were re-genotyped, independent of the proportion of males and females. In practice, the relationship between the density of the LD panel used and the target panel must be considered to determine the number (proportion) of animals that would need to be re-genotyped to enable sufficient imputation accuracy.

Granulometria das partículas e da adição de cal nas propriedades de compósitos madeira-cimento produzidos pelo método de adensamento por vibro compactação / Particle size and lime addiction on properties of wood-cement composites produced by the method of densification by vibro compaction

This paper aimed to evaluate the effects of particle size and the use of lime as a pretreatment of Pinus spp wood particles on the production of wood-cement composites by vibro-compaction densification. Specimens for internal bond and static bending were produced with two different particle sizes: G1, particles that pass through a 4mm screen and were retained at 2mm screen, and G2, particles that pass through a 2mm screen and were retained at 0.84mm screen. The use of lime was also tested in two different methods as pretreatment of wood particles: carbonatation of wood particles before being used in the composite mixture; and addition of hydrated lime directly to the composite mixture. Use of larger particles (G1) presented higher values of internal bond and MOR than composites produced with smaller particles (G2). About the pretreatments, the use of hydrated lime resulted in composites with higher density and better internal bond.(AU)

O presente trabalho visou avaliar o efeito da granulometria e do pré-tratamento com cal das partículas de madeira de Pinus spp na confecção de compósitos madeira-cimento moldados pelo método de adensamento por vibro compactação. Foram produzidos corpos-de-prova para teste de ligação interna e flexão estática com duas diferentes granulometrias de partículas: G1, partículas passantes em uma peneira de 4mm e retidas em uma de 2mm, e G2, partículas passantes em peneira de 2mm e retidas em 0,84mm. Também foram testados o uso da cal por dois diferentes métodos como pré tratamento das partículas de madeira: a carbonatação prévia das partículas antes da confecção dos compósitos e o uso da solução de cal hidratada durante o processo de mistura dos ingredientes. O uso de partículas maiores (G1) apresentou maiores valores de ligação interna e modulo de ruptura quando comparados com compósitos produzidos com partículas menores (G2). Quanto ao pré-tratamento, o uso da cal hidratada resultou em compósitos mais densos e com melhores resultados de ligação interna em relação aos demais tratamentos.(AU)

Granulometria das partículas e da adição de cal nas propriedades de compósitos madeira-cimento produzidos pelo método de adensamento por vibro compactação / Particle size and lime addiction on properties of wood-cement composites produced by the method of densification by vibro compaction

This paper aimed to evaluate the effects of particle size and the use of lime as a pretreatment of Pinus spp wood particles on the production of wood-cement composites by vibro-compaction densification. Specimens for internal bond and static bending were produced with two different particle sizes: G1, particles that pass through a 4mm screen and were retained at 2mm screen, and G2, particles that pass through a 2mm screen and were retained at 0.84mm screen. The use of lime was also tested in two different methods as pretreatment of wood particles: carbonatation of wood particles before being used in the composite mixture; and addition of hydrated lime directly to the composite mixture. Use of larger particles (G1) presented higher values of internal bond and MOR than composites produced with smaller particles (G2). About the pretreatments, the use of hydrated lime resulted in composites with higher density and better internal bond.

O presente trabalho visou avaliar o efeito da granulometria e do pré-tratamento com cal das partículas de madeira de Pinus spp na confecção de compósitos madeira-cimento moldados pelo método de adensamento por vibro compactação. Foram produzidos corpos-de-prova para teste de ligação interna e flexão estática com duas diferentes granulometrias de partículas: G1, partículas passantes em uma peneira de 4mm e retidas em uma de 2mm, e G2, partículas passantes em peneira de 2mm e retidas em 0,84mm. Também foram testados o uso da cal por dois diferentes métodos como pré tratamento das partículas de madeira: a carbonatação prévia das partículas antes da confecção dos compósitos e o uso da solução de cal hidratada durante o processo de mistura dos ingredientes. O uso de partículas maiores (G1) apresentou maiores valores de ligação interna e modulo de ruptura quando comparados com compósitos produzidos com partículas menores (G2). Quanto ao pré-tratamento, o uso da cal hidratada resultou em compósitos mais densos e com melhores resultados de ligação interna em relação aos demais tratamentos.

Particle size and lime addiction on properties of wood-cement composites produced by the method of densification by vibro compaction / Granulometria das partículas e da adição de cal nas propriedades de compósitos madeira-cimento produzidos pelo método de adensamento por vibro compactação

ABSTRACT: This paper aimed to evaluate the effects of particle size and the use of lime as a pretreatment of Pinus spp wood particles on the production of wood-cement composites by vibro-compaction densification. Specimens for internal bond and static bending were produced with two different particle sizes: G1, particles that pass through a 4mm screen and were retained at 2mm screen, and G2, particles that pass through a 2mm screen and were retained at 0.84mm screen. The use of lime was also tested in two different methods as pretreatment of wood particles: carbonatation of wood particles before being used in the composite mixture; and addition of hydrated lime directly to the composite mixture. Use of larger particles (G1) presented higher values of internal bond and MOR than composites produced with smaller particles (G2). About the pretreatments, the use of hydrated lime resulted in composites with higher density and better internal bond.

RESUMO: O presente trabalho visou avaliar o efeito da granulometria e do pré-tratamento com cal das partículas de madeira de Pinus spp na confecção de compósitos madeira-cimento moldados pelo método de adensamento por vibro compactação. Foram produzidos corpos-de-prova para teste de ligação interna e flexão estática com duas diferentes granulometrias de partículas: G1, partículas passantes em uma peneira de 4mm e retidas em uma de 2mm, e G2, partículas passantes em peneira de 2mm e retidas em 0,84mm. Também foram testados o uso da cal por dois diferentes métodos como pré tratamento das partículas de madeira: a carbonatação prévia das partículas antes da confecção dos compósitos e o uso da solução de cal hidratada durante o processo de mistura dos ingredientes. O uso de partículas maiores (G1) apresentou maiores valores de ligação interna e modulo de ruptura quando comparados com compósitos produzidos com partículas menores (G2). Quanto ao pré-tratamento, o uso da cal hidratada resultou em compósitos mais densos e com melhores resultados de ligação interna em relação aos demais tratamentos.