Evaluation of detailed training data to identify risk factors for retirement because of tendon injuries in Thoroughbred racehorses     

Lam KK  Parkin TD  Riggs CM  Morgan KL 《American journal of veterinary research》2007,68(11):1188-1197

OBJECTIVE: To identify the risk factors for premature retirement because of tendon injury in a Thoroughbred racehorse population. ANIMALS: 175 Thoroughbred racehorses (cases) at the Hong Kong Jockey Club that were retired from racing because of tendon injury between 1997 and 2004 and for which the last preretirement exercise was at a fast pace were each matched with 3 control horses that were randomly selected from all uninjured horses that had galloped on the same date as that last exercise episode. PROCEDURES: Training data for all horses were examined. Conditional logistic regression analyses were performed to identify risk factors for retirement from racing attributable to tendon injury. Two multivariable conditional logistic regression models were created; each contained 8 explanatory variables. RESULTS: Compared with control horses, case horses were older at the time of import, accumulated more race distance soon after import, were more likely to have had previous official veterinary or ultrasonographic examinations, raced fewer times during their career, and were in training for a longer period and had exercised at a reduced intensity during the 180-day period preceding the last fast-paced work date. CONCLUSIONS AND CLINICAL RELEVANCE: In addition to identification of risk factors for tendon injury among racing Thoroughbreds, results have suggested that resources focused on obtaining accurate training data may be misdirected in the absence of internationally agreed criteria for incident tendon injury among racehorses. Nevertheless, changes in training intensity and findings of previous clinical examinations could be used to identify horses at risk of tendon injury-associated retirement.  相似文献   

Evaluating the utility of Arabidopsis thaliana as a model for understanding heterosis in hybrid crops     

David Stokes  Colin Morgan  Carmel O’Neill  Ian Bancroft 《Euphytica》2007,156(1-2):157-171

Despite the phenomenon of heterosis having been used to improve crop productivity for almost a century, there is little understanding of the molecular mechanisms involved. Heterosis has been described recently in the widely used plant model Arabidopsis thaliana. To assess the opportunity afforded by this system, we have developed, through pollination to a male sterile female parent (Ler ms1), a range of hybrids of A. thaliana accessions. We tested this method of hybrid production in A. thaliana by comparing seed produced by natural pollination and hand pollination of emasculated plants. Our results demonstrate that using male sterile lines, which more closely represent methods used for hybrid crop production, circumvents the problems associated with the analysis of hybrids produced from emasculated plants. We identified hybrid combinations exhibiting mid-parent heterosis for vegetative fresh weight ranging from −9 to 103% and characterised heterosis in the reciprocal hybrids of one strongly heterotic combination. We found no evidence of a relationship between the extent of genetic relatedness of A. thaliana accessions and the strength of heterosis exhibited by their hybrids. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

Designing grasses with a future – combining the attributes of Lolium and Festuca     

H.M. Thomas  W.G. Morgan  M.W. Humphreys 《Euphytica》2003,133(1):19-26

Lolium species (considered the ideal grasses for European agriculture) are not sufficiently robust to meet many of the environmental challenges that face extensive agriculture in less favoured areas. Fortunately, adaptations to abiotic and biotic stresses exist amongst Festuca species related closely to Lolium. The complex of species has an enormous wealth of genetic variability and potentiality for genetic exchange, thus offering unique opportunities for the production of versatile hybrid varieties with new combinations of useful characters suited to modern grassland farming. The attributes of Lolium and Festuca can be combined into a single genotype by amphiploidy or alternatively, a limited number of characters can be selectively introgressed from Festucainto Lolium or vice versa. Androgenesis of the interspecific hybrids can generate genotypes combining characters that may not be recovered by sexual backcrossing. Genomic in situ hybridization(GISH) can differentially ‘paint’ the chromosomes of Lolium and Festuca and identify Lolium-Festuca recombinant chromosomes. GISH is valuable in the analysis of amphiploids, introgressions and androgenic genotypes and can be used to physically map introgressed traits. Introgression mapping is a powerful new approach to the mapping of traits and arises from a fusion of physical and genetic mapping. For example, in a diploidLolium introgression genotype with only one introgressed Festucasegment, the gene(s) for any Festucaderived trait expressed by the plant must be located within the segment. Using GISH and molecular markers, a dense but highly localised map of the Festuca segment is made in isolation of the Loliumgenome – this may simplify QTL analysis. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Plant regeneration from cultured embryos derived from Hordeum vulgare L. Pollinated with H. Bulbosum L.     

R. A. Pickering  P. W. Morgan 《Euphytica》1983,32(2):585-591

  相似文献   

Spatial variations of rainwash and runoff within apparently homogeneous areas     

Shiu-hung Luk  C. Morgan 《CATENA》1981,8(3-4)

The magnitude and causes of rainwash and runoff variability within small and supposedly “homogeneous” areas were investigated. Artificial rainfall (at 50 mm hr⁻¹ for 30 minutes) was applied to twenty identical 0.0929 m² (1 ft²) mini-plots arranged within a wetted annular 16.5 m² in area. Despite the uniformity of techniques used for data collection, there was considerable variability in the rainwash and runoff data (coefficient of variation= 21 to 35% and 20 to 75% respectively) at the three locations in southern Ontario. In comparison with laboratory data, field rainwash variability was similar but field runoff variability was substantially higher. Soil strength parameters, surface roughness and microtopography, as well as aggregation indices, are considered to be the potential causes of the observed variabilities. Operator variance was found to be extremely significant in our study. It is suggested, therefore, that comparison of erosion data collected by different researchers must be conducted with great caution.  相似文献   

Sexual dimorphism,survival and dispersal in red deer     

E.?A.?CatchpoleEmail author  Y.?Fan  B.?J.?T.?Morgan  T.?H.?Clutton-Brock  T.?Coulson 《Journal of Agricultural, Biological & Environmental Statistics》2004,9(1):1-26

A detailed and extensive mark-recapture-recovery study of red deer on the island of Rum forms the basis of the modeling of this article. We analyze male and female deer separately, and report results for both in this article, but use the female data to demonstrate our modeling approach. We provide a model-selection procedure that allows us to describe the survival by a combination of age-classes, with common survival within each class, and senility, which is modeled continuously as a parametric function of age. Dispersal out of the study area is modeled separately. Survival and dispersal probabilities are examined for the possible influence of both environmental and individual covariates, including a range of alternative measures of population density. The resulting model is succinct and biologically realistic. We compare and contrast survival rates of male and female deer of different ages and compare the factors that affect their survival. We demonstrate large differences in the rate of senescence between males and females even though their senescence begins at the same age. The differences between the sexes suggest that, in population modeling of sexually size-dimorphic species, it is important to identify sex-specific survival functions.  相似文献   

Enzyme-linked immunosorbent assay of ochratoxin A in barley   总被引：3，自引：0，他引：3  

M R Morgan  R McNerney  H W Chan 《Journal of the Association of Official Analytical Chemists》1983,66(6):1481-1484

A noncompetitive, double antibody enzyme-linked immunosorbent assay for ochratoxin A using microtitration plates has been developed and applied to samples of barley. The anti-ochratoxin A antiserum, which is used at high dilution, does not cross-react significantly with ochratoxin B or ochratoxin a. Assay sensitivity for determination of the toxin in barley samples is 60 ng/kg. Minimal sample preparation is required before assay.  相似文献   

A promoter that drives transgene expression in cerebellar Purkinje and retinal bipolar neurons   总被引：13，自引：0，他引：13  

J Oberdick  R J Smeyne  J R Mann  S Zackson  J I Morgan 《Science (New York, N.Y.)》1990,248(4952):223-226

A genomic clone encoding the Purkinje cell-specific L7 protein has been isolated and utilized to drive the expression of beta-galactosidase in mice. Three independent transgenic lines, germ line transformed with an L7-beta-galactosidase fusion gene, exhibit beta-galactosidase expression in both cerebellar Purkinje cells and retinal bipolar neurons. This distribution is the same as that previously determined for the L7 protein by immunohistochemistry. The transgenic murine lines can be used to obtain populations of marked Purkinje and bipolar neurons. Similar L7 promoter constructs can be used to express other foreign genes specifically in these two classes of neurons.  相似文献   

Glazed lunar rocks: origin by impact     

Morgan JW  Laul JC  Ganapathy R  Anders E 《Science (New York, N.Y.)》1971,172(3983):556-558

The glassy coating of lunar rock 12017 is enriched in 15 trace elements relative to the crystalline interior. It apparently consists chiefly of shock-melted rock, somewhat richer in rare earth elements and alkali metals than rock 12017 itself. The glass has been contaminated by about 0.5 percent carbonaceous-chondrite-like material or, alternatively, by a mixture of 0.06 to 0.3 percent fractionated meteoritic material and approximately 10 to 15 percent local soil. The glazing seems to represent molten material splashed from a nearby meteorite impact and not in situ melting by a sudden increase in solar luminosity.  相似文献   

THE RISE OF GENETICS     

Morgan TH 《Science (New York, N.Y.)》1932,76(1969):261-267

  相似文献