Design and laboratory evaluation of a simple fractionating precipitation collector     

Anthony C. Edwards  Malcolm S. Cresser 《Water, air, and soil pollution》1985,26(3):275-280

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Evaluation of alternative land management and cropping practices for soil conservation     

K. Edwards  C.J. Rosewell 《Soil Use and Management》1990,6(3):120-124

Abstract. To allow land planners and managers to assess erosion under alternative management practices a model has been developed. It is based on the universal soil loss equation but uses subfactors for crop cover and management. Readily available agronomic data and field expert opinion were used in formulating the method. Locally-derived data are used to validate the model which is then applied to agricultural systems in New South Wales, ranking the relative erosion hazard associated with crop and land management practices.  相似文献   

Radiographic technique for the pelvis in the standing horse     

S A May  L J Patterson  P J Peacock  G B Edwards 《Equine veterinary journal》1991,23(4):312-314

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Prevalence of equine sarcocystis in British horses and a comparison of two detection methods     

G T Edwards 《The Veterinary record》1984,115(11):265-267

Sarcocystis was detected in oesophageal samples from 245 (62 per cent) of 394 horses and ponies killed at a Cheshire abattoir between February and August 1981. Prevalence of infection was closely related to age, increasing from 28.6 per cent of animals up to two years old to 88.9 per cent of those over eight years old. There were no significant regional differences in prevalence between horses from north west England, Yorkshire or South Wales. Significantly more female horses were infected (69.7 per cent) compared with males (56.2 per cent). Gross examination methods detected fewer than 55 per cent of all infections compared with a tissue digest method. Sarcocysts ranged from 1 to 15 mm in length (mean 5.5 mm) and were up to 0.5 mm wide. Cyst wall morphology and bradyzoite dimensions suggest that the species involved is Sarcocystis bertrami (syn equicanis).  相似文献   

The nephrotoxic potential of neomycin in the horse     

D J Edwards  D N Love  J Raus  J D Baggott 《Equine veterinary journal》1989,21(3):206-210

Neomycin was administered intramuscularly to four normal adult horses at a dose rate of 10 mg/kg bodyweight every 12 h for 10 days (21 doses). The pharmacokinetic behaviour of neomycin with multiple dosing was characterised and a range of blood chemical and urinary parameters examined for evidence of nephrotoxicity. There was evidence of physical renal tubular injury (enzymuria and cylindriuria) within four days of neomycin administration but this subsided following cessation of treatment. No significant functional nephrotoxicity was detected. More severe nephrotoxicity might be expected in ill horses and it is recommended that several clinicopathological results be monitored serially in those horses receiving parenteral neomycin.  相似文献   

Persistence of colonies of Anaplasma marginale in overwintering Dermacentor variabilis     

T M Logan  K M Kocan  W Edwards  J A Hair  P L Claypool  S A Ewing 《American journal of veterinary research》1987,48(4):661-663

Dermacentor variabilis were infected as nymphs with Anaplasma marginale by allowing the ticks to feed on a single infected donor calf. Two weeks after molting to the adult stage, the ticks were allotted into 1 of 3 groups and were allowed to overwinter at room temperature (25 C) in the laboratory (group 1), cold storage (4.5 C) in the laboratory (group 2), or outdoors in leaf litter (group 3). Persistence of A marginale was assessed by determining density of colonies (number of colonies/0.1 mm2 of gut tissue examined) in tick gut specimens at 3, 5, 7, 9, and 12 months after molting to the adult stage. Colonies of A marginale were found in all groups at every density evaluation period. Highest colony densities were observed uniformly in specimens collected at month 7 (May); densities decreased at month 9 and were lowest at month 12. Statistical analysis indicated that ticks subjected to cold storage and to outdoor conditions had similar colony densities of A marginale; the density curve in these 2 groups indicated significant quadratic effects over time, with peak densities in May. Mean colony density in ticks kept at room temperature fit a different quadratic equation. The morphologic data indicated that A marginale overwinters in Dermacentor variabilis, and that increasing numbers of organisms are found from January to May.  相似文献   

Fatal canine neurotoxicosis attributed to blue-green algae (cyanobacteria).     

G J Gunn  A G Rafferty  G C Rafferty  N Cockburn  C Edwards  K A Beattie  G A Codd 《The Veterinary record》1992,130(14):301-302

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A comparison of three rapid diagnostic methods for the detection of rotavirus infection in calves   总被引：1，自引：0，他引：1  

S Edwards  D Chasey  P Napthine  J Banks  C Hewitt-Taylor  M P Cranage 《Veterinary microbiology》1987,13(1):19-25

Three techniques for the detection of rotavirus in faecal samples from calves with neonatal gastroenteritis were compared. A preliminary study indicated that reverse passive haemagglutination (RPHA) was at least as sensitive as the enzyme-linked immunosorbent assay (ELISA). These two immunoassays were compared with the detection of viral RNA by polyacrylamide gel electrophoresis (PAGE) on 209 field samples. Of the 77 samples in which at least one test gave a positive result, 69 were positive by both RPHA and PAGE, but only 49 were also positive by ELISA, indicating a lower sensitivity for the latter test. The overall agreement between RPHA and PAGE was 96%. The reasons for the discrepancies between the tests are discussed.  相似文献   

The effect of freeze/thaw on gaseous nitrogen loss from upland soils     

A.C. Edwards  K. Killham 《Soil Use and Management》1986,2(3):86-91

Abstract. The effect of a short-term freeze/thaw cycle (15°C to -8°C to 15°C) on gaseous N-loss (denitrification and NH₃-volatilization) from intact blocks of an upland soil is described. Rates of both denitrification and NH₃-volatilization were increased by the freeze/thaw cycle, particularly when the blocks had previously been fertilized with urea. Increased gaseous N-loss due to freeze/thaw is reported for soils under heather and under improved grass pasture.  相似文献   

Quantifying habitat specificity to assess the contribution of a patch to species richness at a landscape scale     

Wagner  Helene H.  Edwards  Peter J. 《Landscape Ecology》2001,16(2):121-131

Assessing and predicting the species richness of a complex landscape remains a problem because there is no simple scaling function of species richness in a heterogeneous environment. Furthermore, the potential value of an area for biodiversity conservation may depend on which, rather than how many, species the area contains. This paper shows how we can objectively evaluate the contribution of an area, e.g., a habitat patch, to larger-scale plant species richness, e.g., a landscape composed of patches of several habitat types, and how we can test hypotheses that attempt to explain this contribution. We quantified the concept of habitat specificity to assess the proportion of each observed plant population that is concentrated within a given spatial element. A case study of a biodiversity-monitoring program in the Swiss Canton of Aargau showed that the relative contribution of the three main types of land use to the overall species richness differed strongly between higher taxa (vascular plants and molluscs). However, the type of data, i.e., presence-absence or abundance, was not important. Resampling of the plant data suggested that stratification provided an unbiased estimate of relative specificity, whereas unstratified sampling caused bias even for large samples. In a second case study of vascular plants in an agricultural landscape in central Switzerland, we tested whether the type, size or shape of a landscape element can predict its contribution to the species richness of the landscape. Habitat types that were less frequently disturbed contributed more per m² to landscape species richness than more frequently disturbed ones. Contrary to expectation, patch size was negatively correlated to specificity per m² for arable fields, whereas patch shape appeared to be unrelated to the specificity per m² both for arable fields and for meadows. The specificity approach provides a solution to the problem of scaling species richness and is ideally suited for testing hypotheses on the effect of landscape structure on landscape species richness. Specificity scores can easily be combined with measures of other aspects of rarity to assess the contribution of a spatial element to conservation goals formulated at regional, national or global level.  相似文献