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21.
Phosphorus losses from arable land in England   总被引:7,自引:0,他引:7  
Abstract. Concentrations and annual loadings of molyhdate reactive P (MRP) and total (including particulate) P (TP) are reported from field drainage, catchment and erosion experiments in England. Annual losses through field drains and in catchment runoff were 0.037-0.74 kg MRP/ha and 0.37-2.64 kg TP/ha, but those in surface runoff from experimental plots measuring erosion were generally much greater (often > 3 kg MRP/ha and up to 32 kg TP/ha in a wet year). Amounts of TP in drainflow and catchment runoff depended upon factors influencing soil dispersibility, such as particle size distribution and calcium carbonate content. The results to date suggest that P losses in surface runoff and erosion from arable fields to water are best limited by: (a) maximizing crop cover, using minimal cultivation practices and where possible planting crop rows across rather than up and down the slope, (b) avoiding cultivation practices that result in dispersion of soil particles, and (c) avoiding application of P fertilizer to wet soils when rainfall is likely soon after application. Consideration should he given to maintaining field drains below peak efficiency to reduce subsurface P losses.  相似文献   
22.
The European badger (Meles meles) has been identified as a reservoir for Mycobacterium bovis and is implicated in the maintenance and transmission of tuberculosis in cattle. There is a need for a sensitive test of M. bovis infection in badgers and the current serodiagnostic test used for this purpose has low sensitivity. As observed for other species, assay of interferon-gamma (IFNgamma) produced in response to M. bovis antigens is a more sensitive test of tuberculosis. With this objective in sight, we report the first step in the development of an ELISA for badger IFNgamma. The badger IFNgamma gene was cloned and sequenced and used to generate a specific polyclonal antibody to the cytokine. The gene sequence demonstrated regions that were conserved within the IFNgamma genes of other mammals. The badger sequence was most similar to the canine, showing similar structural organisation of the gene and 88% amino acid identity. Rabbits were immunised with DNA encoding badger IFNgamma and the resulting polyclonal antiserum demonstrated specificity for canine IFNgamma by immunoblot of a commercial recombinant canine IFNgamma. The antiserum was used to detect intracellular badger IFNgamma by flow cytometry analysis of badger lymphocytes stimulated with mitogen.  相似文献   
23.
A randomised, controlled, double-blind, influenza virus, aerosol challenge of horses was undertaken to determine the efficacy of a cold-adapted, temperature sensitive, modified-live virus, intranasal, equine influenza vaccine. Ninety 11-month-old influenza-na?ve foals were assigned randomly to 3 groups (20 vaccinates and 10 controls per group) and challenged 5 weeks, 6 and 12 months after a single vaccination. Challenges were performed on Day 0 in a plastic-lined chamber. Between Days 1 and 10, animals were examined daily for evidence of clinical signs of influenza. Nasal swabs for virus isolation were obtained on Day 1 and Days 1 to 8 and blood samples for serology were collected on Days 1, 7 and 14. There was no adverse response to vaccination in any animal. Following challenge at 5 weeks and 6 months, vaccinates had significantly lower clinical scores (P = 0.0001 and 0.005, respectively), experienced smaller increases in rectal temperature (P = 0.0008 and 0.0007, respectively) and shed less virus (P<0.0001 and P = 0.03, respectively) over fewer days (P<0.0001 and P = 0.002, respectively) than did the controls. After the 12 month challenge, rectal temperatures (P = 0.006) as well as the duration (P = 0.03) and concentration of virus shed (P = 0.04) were significantly reduced among vaccinated animals. The results of this study showed that 6 months after a single dose of vaccine the duration and severity of clinical signs were markedly reduced amongst vaccinated animals exposed to a severe live-virus challenge. Appropriate use of this vaccine should lead to a marked reduction in the frequency, severity and duration of outbreaks of equine influenza in North America.  相似文献   
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OBJECTIVE: To describe a modified ventral stabilization technique for surgical management of atlantoaxial subluxation in dogs and to evaluate the outcome. STUDY DESIGN: Retrospective clinical study. SAMPLE POPULATION: Nineteen client-owned dogs. METHODS: Medical records of 19 dogs with a radiographic diagnosis of atlantoaxial subluxation surgically managed by a modified ventral fixation technique (cortical screws, Kirschner wires, polymethylmethacrylate) were reviewed. Data on pre- and post-operative neurologic status, surgical technique, and complications were retrieved. Follow-up evaluation was performed at approximately 1 month. Telephone interview of the owner was used for long-term assessment (median follow-up for 17 surviving dogs was 10.5 months). RESULTS: Adequate reduction and stabilization was achieved in all dogs based on radiographic assessment immediately after surgery. Improved neurologic outcome occurred in 16 dogs at 1 month and in 15 dogs at follow-up; 2 dogs died of post-operative complications within 24 hours of surgery. One dog was euthanatized at the owners' request because of recurrent neck pain associated with implant failure after 1 month. Two dogs required surgery to remove broken and migrated implants, but further stabilization was not necessary. CONCLUSIONS: Adequate stabilization and improved neurologic outcome was achieved in most dogs. However, on account of the small size of the study and the variable neurologic signs of the dogs on admission, the surgical technique described could not be compared to those previously reported. CLINICAL RELEVANCE: The surgical technique described is an effective means of surgical treatment for atlantoaxial subluxation.  相似文献   
28.
Tydén, E., Bj?rnstr?m, H., Tjälve, H., Larsson, P. Expression and localization of BCRP, MRP1 and MRP2 in intestines, liver and kidney in horse. J. vet. Pharmacol. Therap. doi: 10.1111/j.1365‐2885.2009.01140.x. The gene and protein expression and the cellular localization of the ABC transport proteins breast cancer resistance protein (BCRP), multidrug resistance‐associated protein 1 (MRP1) and multidrug resistance‐associated protein 2 (MRP2) have been examined in the intestines, liver and kidney in horse. High gene and protein expression of BCRP and MRP2 were found in the small intestines, with cellular localization in the apical membranes of the enterocytes. In the liver, MRP2 was present in the bile canalicular membranes of the hepatocytes, whereas BCRP was localized in the cytoplasm of hepatocytes in the peripheral parts of the liver lobuli. In the kidney both BCRP and MRP2 were predominantly present in the distal tubuli and in the loops of Henle. In most tissues, the gene and protein expression of MRP1 were much lower than for BCRP and MRP2. Immunostaining of MRP1 was detectable only in the intestines and with localization in the cytoplasm of enterocytes in the caecum and colon and in the cells of serous acini of Brunner’s glands in the duodenum and the upper jejunum. The latter cells were also stained for BCRP, but not for MRP2. Many drugs used in horse are substrates for one or more of the ABC transport proteins. These transporters may therefore have important functions for oral bioavailability, distribution and excretion of substrate compounds in horse.  相似文献   
29.
Increases in pinyon and juniper woodland cover associated with land-use history are suggested to provide offsets for carbon emissions in arid regions. However, the largest pools of carbon in arid landscapes are typically found in soils, and aboveground biomass cannot be considered long-term storage in fire-prone ecosystems. Also, the objectives of carbon storage may conflict with management for other ecosystem services and fuels reduction. Before appropriate decisions can be made it is necessary to understand the interactions between woodland expansion, management treatments, and carbon retention. We quantified effects of prescribed fire as a fuels reduction and ecosystem maintenance treatment on fuel loads, ecosystem carbon, and nitrogen in a pinyon–juniper woodland in the central Great Basin. We found that plots containing 30% tree cover averaged nearly 40 000 kg · ha?1 in total aboveground biomass, 80 000 kg · ha?1 in ecosystem carbon (C), and 5 000 kg · ha?1 in ecosystem nitrogen (N). Only 25% of ecosystem C and 5% of ecosystem N resided in aboveground biomass pools. Prescribed burning resulted in a 65% reduction in aboveground biomass, a 68% reduction in aboveground C, and a 78% reduction in aboveground N. No statistically significant change in soil or total ecosystem C or N occurred. Prescribed fire was effective at reducing fuels on the landscape and resulted in losses of C and N from aboveground biomass. However, the immediate and long-term effects of burning on soil and total ecosystem C and N is still unclear.  相似文献   
30.
Epulides were diagnosed and surgically removed in 25 dogs. Histologic examination of the epulides indicated that 40% (10/25) were acanthomatous, 32% (8/25) were ossifying, and 28% (7/25) were fibromatous. Recurrence of the tumor directly resulted in the death of 2 dogs. One of these dogs died of malnutrition 13 months after removal of an ossifying epulis, and regrowth of an acanthomatous epulis that was not resected completely resulted in malnutrition and death in another dog 6 months after surgery. Malignant transformation was observed in a third dog 6 months after removal of an ossifying epulis when an osteosarcoma developed where the epulis had been removed. The range of survival was 6 to 134 months, mean survival time was 43.1 months, median survival time was 49 months, and 1-year survival rate was 92%. Satisfactory long-term tumor control was achieved by aggressive surgical treatment of epulides.  相似文献   
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