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The dynamic mating systems of conifers 总被引:4,自引:0,他引:4
J. B. Mitton 《New Forests》1992,6(1-4):197-216
Conifer mating systems vary among species and within species; both ecological variables and genetic variation cause mating systems to be dynamic. Within species, estimates of rates of outcrossing vary among populations, among loci, and among individuals within stands. The level of outcrossing varies with stand density, age, and the abundance of local and foreign pollen. Variation in the mating success of both males and females violates the assumption that populations are randomly mating and at equilibrium, and justifies more quantitative analyses of mating systems. Allelic frequencies in the pollen pool and in the pool of receptive female surfaces may vary through a season and among seasons, producing positively assortative mating in time. Seed and seedling viability selects against homozygotes for lethal alleles and favors heterozygous genotypes, biasing estimates of outcrossing. Particularly fruitful topics of research include the genetic consequences of polyembryony, differential male and female mating success, and associations between specific genotypes and floral phenology. 相似文献
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Seven dogs with torn cruciate ligament were used to evaluate the "over-the-top" repair procedure, using instantaneous center of rotation (ICR). Normal and cruciate-torn stifles of dogs were radiographed before surgery, using an image intensifier videotape system. The injured stifle was reradiographed 6 weeks after surgery. Images of the stifles were photographed from video monitor. Photographs were analyzed by a digitizer hooked to a computer to find the ICR at various angles. Data were analyzed, using multivariate analysis of variance. Relative to those of normal stifles, ICR of the damaged stifles were located significantly (P less than 0.05) proximal and caudal. After surgery, the ICR were still proximal and caudal, but not significantly so. We conclude that the cruciate-torn stifle deviates significantly from normal and that such deviation is restored to normal limits by use of the over-the-top procedure. 相似文献
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Horney BS MacKenzie AL Burton SA Olexson DW Mitton KL Coty WA Rinne SG 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1999,28(1):20-28
A homogenous enzyme immunoassay (EIA) for measurement of serum thyroxine (T4) concentration was evaluated for use with canine and feline serum. The EIA method was linear from 0 to 150 nmol T4/L for human serum, 0 to 94 nmol T4/L for feline serum and 10 to 60 nmol T4/L for canine serum. Intra- and interassay precision studies yielded coefficients of variation = 8% using single point measurements. Method comparison studies gave close agreement between radioimmunoassay (RIA) and EIA results. Correlation coefficients (r values) were 0.88 and 0.97 for canine and feline samples respectively, after application of species-specific factors to correct the calibrator values assigned for human serum samples. The EIA showed no interference from hemolysis at hemoglobin concentrations = 20 g/L or from moderate lipemia. Highly lipemic specimens could be tested after centrifugation to clarify the sample. The EIA showed less interference from autoantibodies to T4 than the RIA method. The EIA method allows automation of T4 testing in a veterinary hospital or laboratory, and can be integrated with the routine clinical chemistry panel. 相似文献
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Gonzalez Mariana Mitton Francesca Maria Miglioranza Karina Silvia Beatriz Peña Aránzazu 《Journal of Soils and Sediments》2019,19(4):1745-1755
Journal of Soils and Sediments - Irrigation or flooding events with riverine waters containing compounds such as surfactants, colloids, and dissolved organic carbon and plant growth will modify... 相似文献
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A. J. Gonzales J. W. Bowman G. J. Fici M. Zhang D. W. Mann M. Mitton‐Fry 《Journal of veterinary pharmacology and therapeutics》2014,37(4):317-324
Janus kinase (JAK) enzymes are involved in cell signaling pathways activated by various cytokines dysregulated in allergy. The objective of this study was to determine whether the novel JAK inhibitor oclacitinib could reduce the activity of cytokines implicated in canine allergic skin disease. Using isolated enzyme systems and in vitro human or canine cell models, potency and selectivity of oclacitinib was determined against JAK family members and cytokines that trigger JAK activation in cells. Oclacitinib inhibited JAK family members by 50% at concentrations (IC50's) ranging from 10 to 99 nm and did not inhibit a panel of 38 non‐JAK kinases (IC50's > 1000 nm ). Oclacitinib was most potent at inhibiting JAK1 (IC50 = 10 nm ). Oclacitinib also inhibited the function of JAK1‐dependent cytokines involved in allergy and inflammation (IL‐2, IL‐4, IL‐6, and IL‐13) as well as pruritus (IL‐31) at IC50's ranging from 36 to 249 nm . Oclacitinib had minimal effects on cytokines that did not activate the JAK1 enzyme in cells (erythropoietin, granulocyte/macrophage colony‐stimulating factor, IL‐12, IL‐23; IC50's > 1000 nm ). These results demonstrate that oclacitinib is a targeted therapy that selectively inhibits JAK1‐dependent cytokines involved in allergy, inflammation, and pruritus and suggests these are the mechanisms by which oclacitinib effectively controls clinical signs associated with allergic skin disease in dogs. 相似文献
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John F. Burka Heather A. Briand Lisa M. Purcell Gregory A. Mitton Jeffrey G. Hogan William P. Ireland 《Fish physiology and biochemistry》1993,12(4):347-355
The effects of altered water temperature in vivo on in vitro smooth muscle contractility of rainbow trout intestine were investigated. Temperature has a significant effect on receptor-mediated
intestinal smooth muscle contractility in the rainbow trout. The efficacy of 5-HT, carbachol, and transmural stimulation increased
with temperatures above 10°C, with an optimal increase at 15°C. There was also a modest increase in the potency of 5-HT and
carbachol within 2 days of establishing trout at 20°C. By day 8, most of these changes had either stabilized or were returning
to control values, suggesting that acclimation changes in membranes and enzyme activities were taking effect. However, the
contractile responses to carbachol and transmural stimulation were still increasing at this time. This may imply that the
muscarinic receptors are more resistant to membrane acclimation changes and may take longer to adapt. Because these experiments
were controlled for handling stress and seasonal changes that affect contractility, we have been able to demonstrate some
early changes in smooth muscle contractility that occur during acclimation to altered temperature. 相似文献
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