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101.
102.
为了解决传统基于经验和类比的设计方法不能设计出截面形状优化的装载机铲斗,不能定量分析铲斗形状变化对装载质量和掘起力的影响问题,提出了一种基于灵敏度分析的铲斗设计方法.通过灵敏度分析建立铲斗回转半径与铲斗斗容、装载机掘起力之间变化曲线,根据灵敏度曲线定量分析铲斗回转半径对铲斗斗容和装载机掘起力的影响程度.提出在满足铲斗斗容设计允许误差的前提下选取装载机掘起力最大的点来确定对应的铲斗截面几何形状参数,并以某型号装载机铲斗设计为例进行了验证.该方法能定量分析铲斗截面几何形状参数对铲斗装载性能的影响,可以支持铲斗快速变型设计. 相似文献
103.
不同氮营养水平对福鼎大白茶产量及品质的影响 总被引:3,自引:0,他引:3
通过田间试验,研究6种氮营养水平对福鼎大白茶茶产量和品质的影响.结果表明:不同氮营养水平能有效提高茶叶产量和品质,其中茶叶产量增产幅度为5% ~18.81%,年施纯氮肥225 kg/hm2处理下茶鲜叶产量最高,发芽密度及百芽重较对照有明显提高;氨基酸增幅为4.40%~6.33%;茶多酚含量降低,平均降幅为1.60%;随着施氮量的增加,茶新梢酚氨比呈现下降趋势,其中年施纯氮肥225 kg/hm2处理下酚氨比值最低,仅为8.81. 相似文献
104.
以湖北省农业科学院与湖北神丹健康食品有限公司联合选育的蛋用鹌鹑H、H2系为父系,L、L2为母系进行配合力测定,选择4个两系配套组合和4个三系配套组合共8个组合:H×L、H×L2、H2×L、H2×L2、H×H2×L、H×H2×L2、H×L×L2、H2×L×L2.结果表明,入舍鹌鹑产蛋总数H×H2×L组最好,达到165枚,平均产蛋率为81.7%,产蛋总重达到1.71kg/只,其次是H×L组,且两组间差异不显著(P>0.05);在实际生产过程中,三系配套生产比两系配套的生产周期长,不易操作,因此建议选择两系配套组合H×L应用于进一步生产实践. 相似文献
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106.
Larruskain A Minguijón E Arostegui I Moreno B Juste RA Jugo BM 《Veterinary immunology and immunopathology》2012,145(1-2):438-446
Maedi-Visna (MV) and ovine pulmonary adenocarcinoma (OPA) are two retroviral diseases occurring worldwide that affect adult sheep. Differences in incidence, which may be related to sheep-rearing and housing choices, as well as to genetics, and disease progression have been reported for both diseases. In this work four microsatellites located in immune-relevant regions, the major histocompatibility complex (MHC) region, interferon-γ and interleukin-12p35, were genotyped to determine their association with disease progression. The analysed sample included Latxa sheep with and without OPA and MV-characteristic lesions in their lungs. The microsatellites in the MHC were the most diverse, while the ones located in the cytokines were the less polymorphic. In the case of IFN-γ the results suggested the presence of null alleles. Significant results were detected for several microsatellite alleles in the association analysis carried out by logistic regression. All statistical analyses included a flock effect adjustment to avoid false positives due to genetic structuration. MHC Class I microsatellite alleles OMHC1*205 and OMHC1*193 were associated with disease progression for Maedi and OPA, respectively. Moreover, MHC Class II microsatellite allele DRB2*275 was associated with presence of lesions in Maedi. Furthermore, the MHC microsatellites were combined for a bioinformatic haplotype inference with the PHASE software. In total, 73 haplotypes were detected, 18 of them in more than 6 animals. After standard and weighted logistic regression analysis, two of them were significantly associated with susceptibility: OMHC1*205-DRB2*271 for Maedi and OMHC1*193-DRB2*271 for OPA, both with the Class I microsatellite alleles associated in the marker by marker study. Although more extensive analyses are needed to disentangle the relationship between host genetics and disease, as far as we know this is the first study demonstrating a significant association between sheep MHC Class I microsatellite alleles and susceptibility to Maedi-Visna and OPA viral diseases. 相似文献
107.
Fabiana Miraglia Zenaide M. de Morais Odir A. Dellagostin Fabiana K. Seixas Julio C. Freitas Francielle G. S. Zacarias Ádina C. Delbem Thaís S. P. Ferreira Gisele O. Souza Rudy A. Hartskeerl Silvio A. Vasconcellos Andrea M. Moreno 《Tropical animal health and production》2012,45(1):117-121
The identification of Leptospira clinical isolates through genotyping and serotyping, besides the recognition of its reservoirs, are important tools for understanding the epidemiology of leptospirosis, and they are also keys for identifying new species and serovars. Fourteen clinical isolates from animals were characterized by means of single enzyme amplified length polymorphism, variable number of tandem repeat analysis, pulsed field gel electrophoresis, and serotyping. All isolates were identified as Leptospira interrogans, serovar Canicola. Infections by this serovar occur in urban regions, where dogs represent the main maintenance hosts, whereas bovine and swine may act as reservoirs of serovar Canicola in rural areas. Both urban and rural aspects of leptospirosis, and the role of domestic animals as maintenance hosts, cannot be neglected in developing and developed countries. 相似文献
108.
Moreno A Chiapponi C Boniotti MB Sozzi E Foni E Barbieri I Zanoni MG Faccini S Lelli D Cordioli P 《Veterinary microbiology》2012,156(3-4):265-276
Three subtypes (H1N1, H1N2, and H3N2) are currently diffused worldwide in pigs. The H1N2 subtype was detected for the first time in Italian pigs in 1998. To investigate the genetic characteristics and the molecular evolution of this subtype in Italy, we conducted a phylogenetic analysis of whole genome sequences of 26 strains isolated from 1998 to 2010. Phylogenetic analysis of HA and NA genes showed differences between the older (1998-2003) and the more recent strains (2003-2010). The older isolates were closely related to the established European H1N2 lineage, whereas the more recent isolates possessed a different NA deriving from recent human H3N2 viruses. Two other reassortant H1N2 strains have been detected: A/sw/It/22530/02 has the HA gene that is closely related to H1N1 viruses; A/sw/It/58769/10 is an uncommon strain with an HA that is closely related to H1N1 and an NA similar to H3N2 SIVs. Amino acid analysis revealed interesting features: a deletion of two amino acids (146-147) in the HA gene of the recent isolates and two strains isolated in 1998; the presence of the uncommon aa change (N66S), in the PB1-F2 protein in strains isolated from 2009 to 2010, which is said to have contributed to the increased virulence. These results demonstrate the importance of pigs as mixing vessels for animal and human influenza and show the presence and establishment of reassortant strains involving human viruses in pigs in Italy. These findings also highlighted different genomic characteristics of the NA gene the recent Italian strains compared to circulating European viruses. 相似文献
109.
110.
Barrère V Alvarez L Suarez G Ceballos L Moreno L Lanusse C Prichard RK 《Veterinary parasitology》2012,186(3-4):344-349
Resistance to benzimidazole anthelmintics in the nematode Haemonchus contortus has been correlated with single nucleotide polymorphisms (SNPs) on the β-tubulin isotype 1 gene. Three mutations can be used as markers for the detection of resistance, namely SNPs at position 200 and 167 (both TTC to TAC) or at position 198 (GAA to GCA). Harbouring a resistance genotype at any one of these codons can lead to a resistant phenotype. Our objective in this study was to analyse the frequencies of the three mutations when the albendazole dose rate and selection pressure were increased. We used adult H. contortus (males and females) collected directly from the abomasum of untreated lambs, or lambs treated with the manufacturer's recommended dose rate (5mg/kg), three times the recommended dose rate (15 mg/kg), or nine times the recommended dose rate (45 mg/kg). Anthelmintic efficacy was determined by worm and egg count reductions. For the surviving worms of the four treatment groups, the frequencies of each resistance SNP at codons 167, 200 and 198 were measured using pyrosequencing. Our results showed a strong relationship between an increasing dose rate and an increase in the frequency of the (TAC)(200) SNP and a decrease in the (TAC)(167) SNP. All worms genotyped were GAA at codon 198. 相似文献