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  • Articles  (9)
  • exponential decay  (3)
  • Bone mineral density  (2)
  • Drosophila melanogaster  (2)
  • Lycopersicon esculentum  (2)
  • Springer  (9)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta applicandae mathematicae 50 (1998), S. 207-224 
    ISSN: 1572-9036
    Keywords: viscoelasticity ; exponential decay ; initial boundary-value problems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We consider the anisotropic and inhomogeneous thermo-viscoelastic equation. We prove that the first and second-order energy decay exponentially as time goes to infinity provided the relaxation function also decays exponentially to zero. While if the relaxation functions decay polynomially to zero, then the energy decays also polynomially. That is, the kernel of the convolution defines the rate of decay of the solution.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 42 (1986), S. 1048-1050 
    ISSN: 1420-9071
    Keywords: Allozyme polymorphism ; linkage disequilibrium ; wine cellar and field populations ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Over three years, theAdh and α-Gpdh loci have been studied in two cellar populations ofDrosophila melanogaster and in two field populations which were each near to one of the cellars. Analyses of gene frequencies indicate that the divergence among subpopulations is greater in theAdh locus than in the α-Gpdh locus. Selection for or againstAdh S allele acting on theIn(2L)t inversion influences of the α-Gpdh alleles. This phenomenon may contribute to explain the maintenance of theAdh and α-Gpdh polymorphism and of theIn(2L)t inversion.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 57 (1995), S. 94-96 
    ISSN: 1432-0827
    Keywords: Androgen insensitivity syndrome ; Hormone replacement therapy ; Bone mineral density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The response of bone mass to long-term treatment with estrogen and progesterone in patients with complete androgen-insensitivity syndrome (AIS) is unknown. We report a 17-year-old female patient (karyotype 46 X, Y) with AIS studied during a 4-year period. Bone mineral density (BMD) measured by dual X-ray absorptiometry in lumbar spine and proximal femur was sharply reduced at the initial visit, and remained unchanged during long-term follow-up on hormone replacement therapy with estrogens and progestin. Bone metabolism markers were all in the normal range. The lack of significant increase in BMD highlights the importance of androgens on bone physiology that cannot be balanced in spite of an appropriate estrogenic milieu.
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  • 4
    ISSN: 1432-0827
    Keywords: Bone mineral density ; Smokers ; Premenopausal women ; Mineral metabolism ; Sex steroids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Smoking is related to decreased bone mass and increased risk of osteoporotic fractures. However, the harmful effects of smoking on bone have not been well characterized. The purpose of this study was to assess the repercussions of smoking on bone mass in premenopausal women, and the relationship between these effects and parameters of mineral metabolism and hormone profile. We measured bone mineral density (BMD) in 101 premenopausal women (47 smokers, 54 nonsmokers) with dualenergy X-ray absorptiometry (DeXA) of the proximal femur and lumbar spine. In a subgroup of the sample (16 smokers, 15 nonsmokers) we measured biochemical indicators of mineral metabolism and hormone profile. BMD in the femoral neck, Ward's triangle, and the intertrochanter region was significantly lower in smoker (P〈0.05) than in nonsmokers. Concentrations of sex hormone-binding globulin were higher, and free testosterone index (FTI) was lower (P〈0.05) in smokers. We found no significant differences between the groups in parameters of mineral metabolism. Concentrations of dehydroepiandrosterone sulfate and free testosterone index were directly correlated with values of BMD in different sites. Our findings show that smoking by premenopausal women is associated with decreased BMD and characteristic changes in the hormone profile.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta applicandae mathematicae 62 (2000), S. 1-21 
    ISSN: 1572-9036
    Keywords: transmission problem ; exponential decay ; partially viscoelastic ; materials with memory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract In this paper we consider the transmission problem of viscoelastic waves. That is, we study the wave propagations over materials consisting of elastic and viscoelastic components. We show that for this types of materials the dissipation produced by the viscoelastic part is strong enough to produce exponential decay of the solution, no matter how small is its size. We also show that the linear model is well posed.
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  • 6
    ISSN: 1573-6857
    Keywords: Drosophila melanogaster ; isofemale lines ; isogroups ; natural populations ; pigmentation ; body size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Studies of short or medium range geographic variations play an increasing role in ecological genetics, and sensitive techniques are required to detect them. In this respect, two sampling techniques were compared inD. melanogaster. The biological data were provided by the analysis of four natural populations from the same geographic area, Spain (one) and Southern France (three), for four morphometrical traits: abdomen and thoracic pigmentation, and wing and thorax lengths. Traits were measured on wild living females and on their progeny reared in the laboratory at 25°C. For progeny analyses, two techniques were compared: the usual isofemale line technique, sib families issued from a single female, and a new isogroup technique, the progeny produced by a group of 20 wild-collected parents. Large phenotypic variations were observed in wild living flies, corresponding to the unstability of natural environmental conditions during their development. Among laboratory grown flies, variations were much smaller. Between isogroups, differences were small, due to sampling error and some common environment effects. Variations between lines were much greater, thus demonstrating a strong genetic component. When different populations have to be compared, the isogroup technique should be preferred since, for the same amount of work, the lesser variability between groups provides a more precise characterization of the population means.
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  • 7
    ISSN: 1573-5060
    Keywords: interplot interference ; Lycopersicon esculentum ; Lycopersicon pennellii ; Lycopersicon pimpinellifolium ; spider mites ; Tetranychus urticae ; tomato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We have previously found an accession of Lycopersicon pimpinellifolium (Jusl.) Mill. (`TO-937') that appeared to resist attack by the two-spotted spider mite (Tetranychus urticae Koch). L. pimpinellifolium is a very close relative of the cultivated tomato (Lycopersicon esculentum Mill.) and thereby a potential source of desirable traits that could be introgressed to the crop species. The objective of this study was to investigate the genetics of the resistance present in `TO-937'. Resistance to infestation by the spider mite was quantified in 24-plant plots of L. pimpinellifolium accessions `TO-937' and `PE-10', L. pennellii accession `PE-45', L. esculentum cultivars `Moneymaker', `Roma' and `Kalohi' (reported to be partially resistant: Stoner & Stringfellow, 1967), and the interspecific F1 cross, L. esculentum `Moneymaker' × L. pimpinellifolium `TO-937'. Only `TO-937', the F1, and`PE-45' were found to be resistant. Resistance of `TO-937' was complete when evaluated in two small greenhouses completely planted with `TO-937' so as to simulate the genotypic homogeneity usual in commercial crops. Generations (P1, P2, F1, F2, BC1P1, and BC1P2) of a P1 (susceptible) × P2 (resistant) cross (`Moneymaker' × `TO-937') were studied for resistance in a single-plant per plot design. Resistance of `TO-937' was inherited with complete dominance and appeared to be controlled by either two or four genes according to whether segregation in the F2 or the BC1P1, respectively, were considered. However, calculation of the number of genes involved in the resistance was complicated by negative interplot interference due to the high frequency of resistant genotypes within most of the generations.
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  • 8
    ISSN: 1573-5060
    Keywords: pollen grain viability ; low temperature ; cold tolerance inheritance ; generation means analysis ; tomato ; Lycopersicon esculentum ; Lycopersicon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The different viabilities of pollen produced at low temperatures in intra- and inter-specific crosses of tomato were studied. Cultivars Red Top, Moneymaker, and Marroqui were crossed with cultivar E-15 and these four cultivars were hybridized with lines of the wild speciesL. pimpinellifolium PE-13,L. parviflorum PE-52,L. pennellii PE-47, andL. hirsutum PE-37 and PE-41. A six-generation family of the Moneymaker x PE-47 cross was obtained to carry out a more detailed genetical study of pollen grain viability at low temperatures. Pollen grain viability was evaluated during the winter via acetocarmine staining. When the parents were compared with their F1, the intra-specific tomato crosses showed dominance to better-quality pollen, theL. esculentum x L. pimpinellifolium inter-specific crosses showed positive heterosis, while the crosses ofL. esculentum with the tolerant speciesL. pennellii andL. hirsutum showed intermediate inheritance. However, in theL. esculentum x L. pennellii family, the dominance and the non-allelic interactions (homozygosis x homozygosis) were the most important factors, so that dominance to better viability at low temperatures appeared to be the general mode of inheritance. Genetical control of pollen grain viability at low temperatures seemed to be polygenetic.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of elasticity 44 (1996), S. 61-87 
    ISSN: 1573-2681
    Keywords: 35B40 ; 35L05 ; 35L70 ; viscoelasticity ; exponential decay ; initial boundary value problems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We consider the viscoelastic plate equation and we prove that the first and second order energies associated with its solution decay exponentially provided the kernel of the convolution also decays exponentially. When the kernel decays polynomially then the energy also decays polynomially. More precisely if the kernel g satisfies g(t) ⩽ -c0g(t)1+1/p and g,g1+1/p ∈ L1(ℝ) with p 〉 2, then the energy decays as 1/(1+t)p.
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