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  • 1
    Electronic Resource
    Electronic Resource
    Genetic architecture of growth curve parameters in chickens (1991)
    Springer
    Theoretical and applied genetics 83 (1991), S. 24-32 
    Details
    ISSN: 1432-2242
    Keywords: Genetics ; Growth curve ; Body weight ; Chickens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Genetic improvement in growth of poultry has traditionally proceeded via selection for body weight at a fixed age. Due to increased maintenance costs and reproductive problems of adult broiler breeders, the potential for genetic manipulation of the growth curve has been receiving increased interest. Research of both male and female progeny of a three-way diallel cross was used to investigate the inheritance of growth curve parameters. The Laird form of the Gompertz equation was used to determine growth curve parameters, and was suited to the juvenile growth data frequently collected from meat-type chickens. Growth rate exhibited significant heterosis due to both autosomes and the sex chromosomes. Age at inflection point also exhibited significant average heterosis, though only among females. Growth rate was also influenced by average line effects, as was age at inflection point. Maternal effects had no influence on growth curve parameters, while additive sex linkage was observed for growth rate. Phenotypic and genetic correlations were calculated among the growth curve parameters and suggest that specific breeding programs could alter the growth trajectory of the contemporary broiler chicken. Moderate heritabilities were observed for the growth curve parameters and support the hypothesis that the growth curve could be altered via genetic manipulation of early postnatal growth, especially during the first 14 days post-hatch.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229222
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Heterosis for concentrations of dopamine, norepinephrine, their metabolites, and epinephrine in the chick hyperstriatum ventrale, hypothalamus, and optic tectum (1992)
    Springer
    Behavior genetics 22 (1992), S. 381-398 
    Details
    ISSN: 1573-3297
    Keywords: Gallus domesticus ; chicks ; diallel ; heterosis ; dominance ; overdominance ; dopamine ; norepinephrine ; epinephrine ; 3,4-dihydroxyphenylacetic acid (DOPAC) ; 3-methoxy-4-hydroxyphenylglycol (MHPG) ; hypothalamus ; hyperstriatum ventrale ; optic tectum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract A complete diallel cross using both sexes was derived from four parental populations of chickens having divergent developmental rates. This paradigm was used to investigate the genetic architecture of the neurochemicals, norepinephrine (NE), epinephrine (EPI), 3,4-dihydroxyphenylacetic acid (DOPAC), dopamine (DA), and 3-methoxy-4-hydroxyphenylglycol (MHPG). No sex differences were found for any genetic parameter investigated. Estimates of average line effects, maternal effects, and additive sex linkage were not significant. Highly significant heterosis, in the form of overdominance, was observed for catecholamine and metabolite concentrations. Hybrids exhibited significant line heterosis in the positive direction for NE, while heterosis for MHPG was observed in the negative direction for all crosses. Heterosis for EPI was both line and brain area specific with the hypothalamus showing greatest heterotic effects. DOPAC showed significant heterosis for all lines only in the optic tectum, and DA showed little heterosis specific to any line, cross, or brain area.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01066669
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  • 3
    Electronic Resource
    Electronic Resource
    Load-cell-design developments by numerical and experimental methods (1981)
    Springer
    Experimental mechanics 21 (1981), S. 341-348 
    Details
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Design data for a family of ring-shaped elastic elements are derived using analytical, numerical and experimental methods. The development of a family of elastic elements for load cells operating at medium to low load level is considered in detail, using several approaches. Snapes analyzed were circular ring with integral bosses and ‘square’ ring. The effects of thickness, boss size and fillet radius (reduced to nondimensional form) on strain/load and defiection/load relationships are evaluated within a given sample space, considering a two-dimensional problem. Thin-ring and curved-beam theory support the analytical approach, with correction terms covering some departures from theoretical shape. Numerical analysis with the finite-element method was mainly used to evaluate the effects of boss size and shape. Accordingly, the required grid patterns were developed using a mesh-generating method capable of covering the range of parameters considered. A set of configurations was selected, enabling single and combined effects to be analyzed with little entanglement between estimates. For the square ring, frame theory and a limit solution for the case of the plate with central hole are resorted to. Photoelastic tests were performed, covering a range of shapes by sequential remachining of the model, and equal contigurations were analyzed with the finite-element method. Strain-gage tests on actual elastic elements were made, considering also the results of a series of tests carried out at the Metrology Institute some time ago. Results obtained yield comprehensive information on the effect of several parameters on the load-output transfer function of ring-shaped elastic elements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02326234
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  • 4
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    Load-cell-design developments by numerical and experimental methods (1981)
    Springer
    Details
    Publication Date: 1981-09-01
    Print ISSN: 0014-4851
    Electronic ISSN: 1741-2765
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Springer
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