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The occurrence of equine arteritis virus in Australia 总被引:2,自引:0,他引:2
This paper reports the first isolation of equine arteritis virus (EAV) in Australia and serological evidence of exposure to EAV in Australian horses. Twelve Standardbred stallions imported from North America were found to shed EAV in semen. One hundred and seven stallions were tested for serum antibodies to EAV and 73% of Standardbred stallions tested were seropositive as compared to 8% of Thoroughbred stallions. Serum antibody was detected in 71% of Standardbred mares, 6% of Standardbred racehorses and 1% of Thoroughbred mares and racehorses. Examination of stored serums demonstrated that EAV had been present in Australia since at least 1975. 相似文献
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Characteristic site disturbance due to harvesting and extraction machinery traffic on sensitive forest sites with peat soils 总被引:2,自引:0,他引:2
Ciaran Nugent Christopher Kanali Philip M. O. Owende Martin Nieuwenhuis Shane Ward 《Forest Ecology and Management》2003,180(1-3):85-98
The effects of wood harvesting and extraction machinery traffic on sensitive forest sites with peat soils were characterised with the objective of quantifying the threshold levels beyond which significant site impacts (compaction and rutting) would occur. The treatments involved running the machines in selected extraction racks (i.e., 3 m wide machine routes) while conducting normal wood thinning and extraction operations comprising one and two passes by the harvester and the forwarder with full payload, respectively. Soil disturbance thresholds were established by testing the level of significance of the difference in induced soil damage and compaction before and after machine traffic treatments. For volumetric soil water content lying between 10.0 and 14.9%, threshold cone penetration resistance levels for two 600/55–30.5 tyres were found to range from 594 to 640 kPa for deep-raised peat soil with initial strength lying between 524 and 581 kPa. In general, the proportion of the total rut depth data in each rack that exceeded the threshold level of 21.5 cm was about 5%. The threshold value corresponds to sinkage equivalent to 15% of the overall wheel diameter of the harvester, above which machine mobility would be hampered considerably. In addition, after harvester traffic the mean rut depth per unit rack length was 10.2×10−2 cm/m, and it ranged from 0.7 to 24.7×10−2 cm/m. 相似文献
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PM Lundquist R Wortmann C Geletneky RJ Twieg M Jurich VY Lee CR Moylan DM Burland 《Science (New York, N.Y.)》1996,274(5290):1182-1185
The performance of amorphous organic photorefractive (PR) materials in applications such as optical data storage is generally limited by the concentration of active molecules (chromophores) that can be incorporated into the host without forming a crystalline material with poor optical quality. In polymeric PR systems described previously, performance has been limited by the necessity of devoting a large fraction of the material to inert polymer and plasticizing components in order to ensure compositional stability. A new class of organic PR materials composed of multifunctional glass-forming organic chromophores is described that have long-term stability and greatly improved PR properties. 相似文献
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PC Sereno DB Dutheil M Iarochene HCE Larsson GH Lyon PM Magwene CA Sidor DJ Varricchio JA Wilson 《Science (New York, N.Y.)》1996,272(5264):986-991
Late Cretaceous (Cenomanian) fossils discovered in the Kem Kem region of Morocco include large predatory dinosaurs that inhabited Africa as it drifted into geographic isolation. One, represented by a skull approximately 1.6 meters in length, is an advanced allosauroid referable to the African genus Carcharodontosaurus. Another, represented by a partial skeleton with slender proportions, is a new basal coelurosaur closely resembling the Egyptian genus Bahariasaurus. Comparisons with Cretaceous theropods from other continents reveal a previously unrecognized global radiation of carcharodontosaurid predators. Substantial geographic differentiation of dinosaurian faunas in response to continental drift appears to have arisen abruptly at the beginning of the Late Cretaceous. 相似文献
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Barron PJ McDonnell KP Ward SM Owende PM 《Journal of agricultural safety and health》2005,11(3):373-377
Operator field of view is of primary importance for efficient and safe operation of field machines such as tractors, forest harvesting machines, and earthmoving equipment. This research uses a light source with a series of light sensors, and a contour plot of a derived visibility index, to quantify the masking effect of obstructions on the light source and to map the blind areas due to inherent obstructions in the field of view. The described method provides a quantified two-dimensional assessment of the blind areas in the workspace and could be used for rapid assessment of potential limitations in operator visibility for field machines. 相似文献
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Adaptation of thermal threshold analgesiometry for NSAIDs in cats: effects of ketoprofen 总被引:1,自引:0,他引:1
Nonsteroidal anti‐inflammatory drugs (NSAIDs) are widely used to provide analgesia in clinical veterinary medicine, but there are few objective data evaluating this effect under controlled conditions in cats. Analgesia is more difficult to detect with acute analgesiometry after NSAIDs than after opioids. This investigation aimed to adapt the feline thermal analgesiometry method previously employed with opioids ( Dixon et al. 2002 ) for use with NSAIDs. Ketoprofen, a COX1 inhibitor licensed for cats was chosen. Six cats (2 neutered, four entire females, weighing 2.2–5.4 kg) were studied in two blinded randomized crossover trials each at least 2 weeks apart. Thermal thresholds (TT) were measured using the thermal threshold‐testing device previously developed for cats. A heater element and temperature sensor in a small probe were held at constant pressure against the cats' shaved thorax with an elasticized band. Skin temperature was recorded before each test, then the heater activated. When the cat responded by flinching, turning or jumping the heater was turned off and the temperature recorded. In the first study TT were measured following subcutaneous (SC) injection of ketoprofen (2 mg kg?1) or a similar volume of saline. In the second study, prior to TT, and under isoflurane restraint, a mild inflammatory focus was produced at the probe site by five SC injections of 5 mg kaolin in 0.1 mL saline at each corner and in the center of a 1.5‐cm square. Saline or ketoprofen as in the first study were injected at the same time. Three baseline temperatures were recorded before any injections were given. Thermal thresholds were measured at 1 and 2 hours and then two‐hourly for 24 hours. Data were analysed using anova . Baseline skin temperature increased (37.3 ± 0.5–38.1 ± 0.8 °C) 24 hours after saline injection in study 2 (p < 0.05) but did not change after any other treatment. Thermal thresholds decreased (40.0 ± 1.3 to 39.1 ± 0.4 °C) 16 hours after ketoprofen in study 1 (p < 0.05) and increased (41.6 ± 1.5–44.8 ± 6.1 °C) 16–24 hours after ketoprofen in study 2 (p < 0.05), with no significant changes after saline. No obvious increase in sensitivity to thermal stimulation after kaolin injection was detected although obvious inflammation was present for up to 36 hours and the cats responded to digital pressure at the treated site. The method detected some effects of a COX1 selective NSAID and may be suitable for future NSAID studies in cats. However, a pressure stimulus ( Dixon et al. 2000) may prove better than thermal, and it requires investigation. 相似文献