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1.
J K Skeeles M Slavik J N Beasley A H Brown C F Meinecke S Maruca S Welch 《American journal of veterinary research》1980,41(9):1458-1461
Specific-pathogen-free White Leghorn chickens were inoculated with a field strain of infectious bursal disease virus. One group (A) was inoculated at 17 days after the chicks were hatched, and the other groups (C and E) were inoculated at posthatch day 42. Blood samples were obtained for determination of clotting times (whole blood recalcification, prothrombin, and activated partial thromboplastin times), virus-neutralizing antibody, and total hemolytic complement. There were significant increases in clotting times for groups C and E at 3 and 5 days after they were inoculated. There were no significant increases in clotting times at 3 days after inoculation in the group A chickens (inoculated at 17 days after hatching). There were no significant decreases in total complement activity in any of these chickens (groups A, C, and E). This study indicates that the mortality and clinical symptoms observed in chickens experimentally infected with infectious bursal disease virus may be associated with a clotting abnormality because it was noted only in chickens that developed severe clinical disease (inoculated at 42 days after hatching) and was not noted in chickens that remained clinically normal (inoculated at 17 days). 相似文献
2.
Maurice Keith R. Welch Joan M. Brown Christopher P. Latham Roger Earl 《Landscape Ecology》2004,19(6):603-620
The Pocono mesic till barrens (PMTB) are a unique assemblage of fire-maintained shrub communities that support numerous rare species. Historically these barrens covered a large area in the vicinity of Long Pond, Pennsylvania, USA. However, due largely to regional fire suppression instituted in the early 1960s, over 70% of the area covered by barrens succeeded to fire-intolerant forest that does not support the rare species. We investigated the influence of forest proximity on barrens succession across three geomorphic types during periods of high fire frequency and fire suppression, testing the hypothesis that forest processes such as seed rain, shading, and detrital enrichment of soils enhances barrens succession through a contagion effect. Evidence of a forest contagion effect should be shown by increased rates of barrens succession with increasing proximity to the nearest forest edge. In order to detect a forest contagion effect, barrens persistence and barrens succession were modeled in proximity zones of 0-50 m, 50-100 m, 100-200 m, and greater than 200 m from the nearest forest edge. We used existing GIS data layers for fire, geomorphology, and vegetation distribution in 1938, 1963, and 1992. The layers were modified and overlain using ArcView software to determine persistence and succession rates for each unique combination of layers in each proximity zone from 1938 to 1963 (pre-fire suppression) and 1963 to 1992 (post-fire suppression). ANCOVA results indicate that proximity to the nearest forest edge significantly affected barrens persistence rates in both time periods, but succession rates were significantly affected in 1938 to 1963 only. Twenty-eight percent of the 1938 barrens succeeded to forest by 1963; 56% of the 1963 barrens became forest by 1992. Results support previous findings that barrens persistence is enhanced by increased fire frequency, and that barrens persist longer where they overlie flat glacial till than on other geomorphology types. 相似文献
3.
The evidence at present available, although incomplete, gives rise to fears for the future of the edible snail Helix pomatia L. The scale of exploitation is increasing, particularly in Eastern Europe, to meet growing demand, mainly from the West. The growth of legislation to control collecting supports the evidence of declining numbers, but the legislation does not appear to be backed by sufficiently detailed population ecology studies. The need for co-ordinated international action on farming, legislation and ecological study is urged. 相似文献
4.
In laboratory incubations, the times to 50% loss (DT50) of a first application of napropamide were approximately 25, 45 and 75 days in soil incubated at 25, 15 and 5°C respectively. When treated for a second time, the DT50 values were 4, 7 and 15 days at the same temperatures, irrespective of the temperature of the first incubation. This indicates that enhanced degradation of napropamide in soil can be both induced and expressed at low temperature. A mixed microbial culture able to degrade the herbicide to a single degradation product, identified by HPLC retention time as naphthoxypropionic acid, was obtained from a soil capable of rapid degradation. Addition of a sub-sample of this mixed culture to a previously untreated soil introduced rapid degrading ability. When small amounts of soil capable of rapid degradation were added to previously untreated soil, in both the laboratory and the field, the degradation rate of napropamide increased compared with that in unamended soils. 相似文献
5.
Exogenous eFSH, follicle coasting, and hCG as a novel superovulation regimen in mares 总被引:3,自引:0,他引:3
S.A. Welch MS D.J. Denniston PhD J.J. Hudson DVM MS J.E. Bruemmer PhD P.M. McCue DVM PhD E.L. Squires PhD 《Journal of Equine Veterinary Science》2006,26(6):262-270
The objective of this study was to evaluate various equine follicle-stimulating hormone (eFSH) treatment protocols and the effect of “follicle coasting” on ovulation and embryo recovery rates in mares. Cycling mares (n = 40) were randomly assigned to one of four groups 7 days after ovulation: (1) 12.5 mg eFSH twice daily until follicles were 35 mm or larger; (2) 12.5 mg eFSH twice daily until follicles were 32 mm or larger; (3) 12.5 mg eFSH twice daily for 3.5 days followed by 12.5 mg eFSH enriched with luteinizing hormone (LH) twice daily until follicles were 35 mm or larger; and (4) 25 mg eFSH once daily until follicles were 32 mm or larger. Mares in groups 1 and 3 were injected with human chorionic gonadotropin (hCG) (2500 IU intravenously) at the end of eFSH treatment, whereas mares in groups 2 and 4 were given hCG approximately 42 and 54 hours, respectively, after the last eFSH treatment (“follicle coasting”). Nonsurgical embryo collection was performed 6.5 to 7.5 days after ovulation. Each mare experienced a nontreated estrous cycle before being reassigned to a second treatment. Ovulation rates for mares in treatment groups 1 to 4 were 3.3 ± 0.4, 4.1 ± 0.4, 3.5 ± 0.4, and 2.8 ± 0.4 (mean ± SEM; P < .05), respectively. One or more embryos were recovered from more than 80% of mares in each treatment group, and embryo recovery rate per flush was similar among treatment groups (1.9 ± 0.3, 2.6 ± 0.3, 1.9 ± 0.3 and 1.9 ± 0.3, respectively; P > .05). The overall embryo recovery rate was 2.1 ± 1.5 embryos per flush. In summary, ovulation rate was higher for mares treated with eFSH (3.4 ± 0.4) compared with non-treated controls (1.1 ± 0.2). Ovulation rate in mares in which hCG was delayed (follicle coasting) was higher (P < .05) when treatments were given twice per day versus once per day. Administration of equine luteinizing hormone (eLH) in conjunction with eFSH did not have an advantage over mares treated only with eFSH. 相似文献
6.
7.
8.
OBJECTIVE: To determine the effect of a porcine-derived small intestinal submucosa product (PSIS) on healing time, epithelialization, angiogenesis, contraction, and inflammation of wounds with exposed bone on the distal aspect of the limbs of dogs. STUDY DESIGN: Prospective, controlled, experimental study. ANIMAL POPULATION: 10 young adult, purpose-bred, male Beagles. METHODS: Small wounds with exposed bone were created on the lateral aspect of metatarsal V and the medial aspect of metatarsal II on both hindlimbs. Three sheets of PSIS were sutured into the wounds of the treated limb, and the other limb served as a control. On day 10, punch biopsies of the medial metatarsal wounds were collected and were evaluated microscopically after routine hematoxylin and eosin and phosphotungstic acid hematoxylin (PTAH) staining. The lateral metatarsal wounds were evaluated by planimetry and laser Doppler perfusion imaging on days 7, 14, and 21. Time until complete wound healing was also recorded. The level of significance was set at P < or =.05 for all statistical analyses. RESULTS: Laser Doppler perfusion measurements were significantly higher in control wounds on day 7, but no differences were noted on days 14 and 21. No significant differences in planimetric values, histopathologic appearance, or time until complete wound healing were noted among treated and control groups. CONCLUSIONS: No objective differences in healing were noted between control wounds and wounds treated with PSIS. CLINICAL RELEVANCE: There appears to be no contraindication to the use of PSIS on clean wounds with exposed bone on the distal limbs of dogs. However, our objective data provides no evidence that this product affects epithelialization, contraction, or time to complete healing in wounds with exposed bone. 相似文献
9.
BACKGROUND: In 2001 the UK Department of Health funded pilot community-based interventions to improve fruit and vegetable intakes in five economically deprived areas of England. The effectiveness of the programme and the use of a brief tool for evaluating community interventions are reported here. METHODS: Data on intakes of and beliefs about fruit and vegetables were collected by a short postal questionnaire (FACET--Five-a-day Community Evaluation Tool) simultaneously from 810 individuals living in the pilot communities and 270 individuals who were participating in an unrelated observational study (controls). Data were collected before and after a 12-month intervention period. Quantitative dietary data derived from 7-day food diaries available for control subjects were used to assess the ability of the FACET questionnaire to estimate fruit and vegetable intakes. RESULTS: Compared with controls, the intervention group significantly increased their knowledge of the 5-a-day optimum (P<0.01) and reported increased access to fruits and vegetables (P<0.001). Overall, the intervention had no demonstrable effect on total fruit and vegetable intakes as measured by FACET. However, smoking habit strongly predicted change in fruit and vegetable intakes (P<0.01) in the intervention group. Opposite trends were observed in the two groups, with 'smokers' and 'non-smokers' in the intervention and control groups respectively reducing their fruit and vegetable intakes. The FACET questionnaire agreed with food diary estimates of fruit and vegetable intakes in 56% of cases. CONCLUSIONS: Community-based interventions can produce important changes in knowledge of and access to fruit and vegetables. However, in this study change in fruit and vegetable intakes was strongly influenced by smoking habit. This bias needs to be considered in planning future intervention and evaluation programmes. The FACET questionnaire provides acceptable estimates of fruit and vegetable intakes which may be used for grading intake in large community-based projects. 相似文献
10.
Quantitative trait loci for phytate in rice grain and their relationship with grain micronutrient content 总被引:6,自引:0,他引:6
James C. R. Stangoulis Bao-Lam Huynh Ross M. Welch Eun-Young Choi Robin D. Graham 《Euphytica》2007,154(3):289-294
Phytate (inositol-hexa-phosphate) has an important role in plants but it also may have anti-nutritional properties in animals
and humans. While there is debate within the plant breeding and nutrition communities regarding an optimum level in grain,
there appears to be little information at the molecular level for the genetics of this trait, and its association with important
trace elements, in particular, Fe and Zn. In this preliminary study, quantitative trait loci (QTL) for grain phytates, Zn
and Fe in glasshouse-grown rice lines from an IR64 × Azucena doubled haploid population were identified. Correlations between
phytate and essential nutrients were also studied. Transgressive segregation was found for most traits. Phytate and total
P concentrations had one QTL in common located on chromosome five with the (high concentration) allele contributed from Azucena.
There were significant positive correlations between phytate and inorganic phosphorus (P), total P, Fe, Zn, Cu and Mn concentrations
for both grain concentration and content. However, the QTLs of phytate were not located on the same chromosomal regions as
those found for Fe, Zn and Mn, suggesting that they were genetically different and thus using molecular markers in breeding
and selection would modify the phytate level without affecting grain micronutrient density. 相似文献