Necropsy findings of koalas from the Mount Lofty Ranges population in South Australia          下载免费PDF全文

KN Speight  P Hicks  C Graham  W Boardman  WG Breed  E Manthorpe  O Funnell  L Woolford 《Australian veterinary journal》2018,96(5):188-192

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Surveillance of West Nile virus in horses in Canada: A retrospective study of cases reported to the Canadian Food Inspection Agency from 2003 to 2019     

Antoine Levasseur  Julie Arsenault  Julie Par 《The Canadian veterinary journal. La revue veterinaire canadienne》2021,62(5):469

The objectives of the study were to describe the regional and provincial incidence rates and the weekly distribution of 842 reported West Nile virus (WNV) cases in horses in Canada between 2003 and 2019. This study also investigated characteristics of cases reported to the Canadian Food Inspection Agency (CFIA) between 2015 and 2019. The western region (British Columbia, Alberta, Saskatchewan, and Manitoba) had higher incidence rates than the eastern region (Ontario, Quebec, and Atlantic provinces) and overall, Saskatchewan registered the highest incidence. Over the study period, an earlier weekly preliminary onset of WNV cases was observed in the western region. The vast majority of cases were unvaccinated (96%), most cases were Quarter Horses (68%) and the risk of mortality was 31.9%. The findings of this study may be useful in informing veterinary equine practitioners about measures to prevent WNV disease in horses in Canada.  相似文献   

Differential effect of nematicide treatments on tuber yields in early- and late-maturing potato cultivars     

J. Kimpinski †  W. J. Arsenault  A. V. Sturz 《Plant pathology》2001,50(4):509-514

A 3-year field study examined the effects of 1,3-dichloropropene or oxamyl on tuber yields in four early- and five late-maturing potato cultivars. The nematicide treatments increased total tuber yield by ≈ 12% for early-maturing cultivars, but by less than 2% for the late-maturing cultivars. The treatments reduced the numbers of root lesion nematodes (primarily Pratylenchus penetrans ), which were the dominant plant parasitic nematodes at the site. Covariance analysis indicated that treatment effects on total tuber yield were no longer significant after adjusting for root lesion nematodes in soil at harvest, confirming that these nematodes had a direct effect on the host. As expected, there were significant inverse relationships ( P  = 0·05) between total tuber yields and numbers of root lesion nematodes in soil and in roots. However, the application of nematicides in late-maturing cultivars was found to be of no practical value. Crop production systems designed to reduce or optimize pesticide applications can form one criterion in the development of more environmentally sensitive management strategies. The merit of utilizing chemicals for root lesion nematode control are considered with regard to cultivar maturity.  相似文献   

Angiographic classification of patent ductus arteriosus morphology in the dog   总被引：1，自引：1，他引：1  

Matthew W. Miller DVM  Dipl ACVIM  Sonya G. Gordon DVM  Dipl ACVIM  Ashley B. Saunders DVM  Dipl ACVIM  Wendy G. Arsenault DVM  Dipl ACVIM  Kathryn M. Meurs DVM  Dipl ACVIM  Linda B. Lehmkuhl DVM  Dipl ACVIM  John D. Bonagura DVM  Dipl ACVIM  Philip R. Fox DVM  Dipl ACVIM  Dipl ECVIM 《Journal of Veterinary Cardiology》2006,8(2):109-114

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Bottom-up dependent gating of frontal signals in early visual cortex     

Ekstrom LB  Roelfsema PR  Arsenault JT  Bonmassar G  Vanduffel W 《Science (New York, N.Y.)》2008,321(5887):414-417

The frontal eye field (FEF) is one of several cortical regions thought to modulate sensory inputs. Moreover, several hypotheses suggest that the FEF can only modulate early visual areas in the presence of a visual stimulus. To test for bottom-up gating of frontal signals, we microstimulated subregions in the FEF of two monkeys and measured the effects throughout the brain with functional magnetic resonance imaging. The activity of higher-order visual areas was strongly modulated by FEF stimulation, independent of visual stimulation. In contrast, FEF stimulation induced a topographically specific pattern of enhancement and suppression in early visual areas, but only in the presence of a visual stimulus. Modulation strength depended on stimulus contrast and on the presence of distractors. We conclude that bottom-up activation is needed to enable top-down modulation of early visual cortex and that stimulus saliency determines the strength of this modulation.  相似文献   

Formation of Chiral Interdigitated Multilayers at the Air-Liquid Interface Through Acid-Base Interactions     

I Kuzmenko  R Buller  WG Bouwman  K Kjaer  J Als-Nielsen  M Lahav  L Leiserowitz 《Science (New York, N.Y.)》1996,274(5295):2046-2049

Thin interdigitated films composed of a long-chain, water-insoluble chiral acid (p-pentadecylmandelic acid of absolute configuration R) and a water-soluble chiral base (phenylethylamine, R') were constructed at the air-solution interface. The (R, R') structure was characterized to near-atomic resolution by grazing-incidence x-ray diffraction (GIXD). The two diastereomeric systems, (R, R') and (R, S'), demonstrate similar surface pressure-molecular area isotherms, but their structures are completely different on the molecular level, as monitored by GIXD. Complementary data on these two architectures were provided by atomic force microscopy.  相似文献   

Pharmacokinetics of carvedilol after intravenous and oral administration in conscious healthy dogs     

Arsenault WG  Boothe DM  Gordon SG  Miller MW  Chalkley JR  Petrikovics I 《American journal of veterinary research》2005,66(12):2172-2176

OBJECTIVE: To determine the pharmacokinetics of carvedilol administered IV and orally and determine the dose of carvedilol required to maintain plasma concentrations associated with anticipated therapeutic efficacy when administered orally to dogs. ANIMALS: 8 healthy dogs. PROCEDURES: Blood samples were collected for 24 hours after single doses of carvedilol were administered IV (175 microg/kg) or PO (1.5 mg/kg) by use of a crossover nonrandomized design. Carvedilol concentrations were detected in plasma by use of high-performance liquid chromatography. Plasma drug concentration versus time curves were subjected to noncompartmental pharmacokinetic analysis. RESULTS: The median peak concentration (extrapolated) of carvedilol after IV administration was 476 ng/mL (range, 203 to 1,920 ng/mL), elimination half-life (t(1/2)) was 282 minutes (range, 19 to 1,021 minutes), and mean residence time (MRT) was 360 minutes (range, 19 to 819 minutes). Volume of distribution at steady state was 2.0 L/kg (range, 0.7 to 4.3 L/kg). After oral administration of carvedilol, the median peak concentration was 24 microg/mL (range, 9 to 173 microg/mL), time to maximum concentration was 90 minutes (range, 60 to 180 minutes), t(1/2) was 82 minutes (range, 64 to 138 minutes), and MRT was 182 minutes (range, 112 to 254 minutes). Median bioavailability after oral administration of carvedilol was 2.1% (range, 0.4% to 54%). CONCLUSIONS AND CLINICAL RELEVANCE: Although results suggested a 3-hour dosing interval on the basis of MRT, pharmacodynamic studies investigating the duration of beta-adrenoreceptor blockade provide a more accurate basis for determining the dosing interval of carvedilol.  相似文献   

Endophytic bacterial communities in the periderm of potato tubers and their potential to improve resistance to soil-borne plant pathogens   总被引：17，自引：0，他引：17  

Sturz  Christie  Matheson  Arsenault  & Buchanan 《Plant pathology》1999,48(3):360-369

To evaluate whether the location of bacterial endophyte communities contributes to disease resistance in potato tubers ( Solanum tuberosum ), the population density, biodiversity and antibiotic activity of endophytic bacteria was examined from the tuber peel (periderm plus top 3 mm of tissue) of four cultivars (Russet Burbank, Kennebec, Butte and Shepody). There were no significant differences for population density of bacteria among the layers of peel examined and no cultivar × peel layer interaction. Endophytic bacteria from several layers of peel were challenged in in vitro bioassays to the soil-borne plant pathogens Fusarium sambucinum , Fusarium avenaceum , Fusarium oxysporum and Phytophthora infestans (mating types A1 and A2). In general, antibiosis of bacterial endophytes against these pathogens was significantly higher ( P  = 0.01) in isolates recovered from the outermost layer of tuber peel and decreased progressively toward the centre of the tuber. Antibiosis against P. infestans was variable, with a progressive decrease in antibiotic activity from outer to inner layers of peel occurring in cvs Russet Burbank and Kennebec only. For antibiosis there were significant cultivar × peel, and cultivar × pathogen interactions ( P  = 0.01). In all cases the inhibitory activity of endophytic bacteria was significantly greater ( P  = 0.01) against the A1 than the A2 mating type of P. infestans . In four of seven cases, where the same species of bacteria were recovered from all three peel layers, antibiosis to pathogens decreased significantly ( P  = 0.01) with depth of recovery (from the periderm to inside the tuber), indicating that in certain communities of endophytic bacteria, defence against pathogens may be related to bacterial adaptation to location within a host and may be tissue-type and tissue-site specific.  相似文献   

Effects of nitrogen fertilization and in-row seedpiece spacing on yield of three potato cultivars in Prince Edward Island     

W. J. Arsenault  A. Malone 《American Journal of Potato Research》1999,76(4):227-229

AC Novachip and NorWis were recently introduced as new potato (Solanum tuberosum L.) chip cultivars on Prince Edward Island (P.E.I.), Canada. Variability of nitrogen application and in-row seedpiece spacing, required for maximum yield, exist among cultivars presently grown in P.E.I. This study was conducted to determine the N rate and in-row seedpiece spacing required for optimum production of AC Novachip and NorWis compared to the standard cultivar Norchip, and also, to determine the effects of treatments and harvest dates on AC Novachip. Treatments included N applied at 90, 134, and 179 kg/ha with in-row seedpiece spacings at 20.3, 25.4 and 30.5 cm. In addition to the 120 day harvest for all three cultivars, treatments for AC Novachip were also harvested at 80 and 100 days after planting. For the 120 day harvest, yield of Canada No. 1 size tubers was higher for NorWis compared to Norchip while yields for AC Novachip and Norchip were similar. Nitrogen application had no effect on yields of AC Novachip. Similar to Norchip, increasing the rate of applied N more than 134 kg/ha resulted in little or no increase in yields of NorWis. Yields of Canada No. 1 size tubers decreased as in-row spacing increased for AC Novachip and were greater at 25.4 compared to 30.5 cm spacing for Norchip. In-row seed-piece spacing had no affect on Canada No. 1 size tuber yields of NorWis. Increasing the days to harvest increased the yields of AC Novachip. Nitrogen rate or in-row spacing had no effect on Canada No. 1 yields of AC Novachip at the 80 and 100 day harvests. The results of this study suggest that little gain in yield of Canada No. 1 size tubers for NorWis, similar to the standard cultivar Norchip, can be obtained with N application more than 134 kg/ha or for AC Novachip by increasing the rate of N from 90 to 179 kg/ha. Unlike NorWis yields of AC Novachip and NorWis are reduced when in-row seedpiece spacing is increased from 25.4 to 30.5 cm.  相似文献   

The need to implement the landscape of fear within rodent pest management strategies          下载免费PDF全文

Inge M Krijger  Steven R Belmain  Grant R Singleton  Peter WG Groot Koerkamp  Bastiaan G Meerburg 《Pest management science》2017,73(12):2397-2402

Current reactive pest management methods have serious drawbacks such as the heavy reliance on chemicals, emerging genetic rodenticide resistance and high secondary exposure risks. Rodent control needs to be based on pest species ecology and ethology to facilitate the development of ecologically based rodent management (EBRM). An important aspect of EBRM is a strong understanding of rodent pest species ecology, behaviour and spatiotemporal factors. Gaining insight into the behaviour of pest species is a key aspect of EBRM. The landscape of fear (LOF) is a mapping of the spatial variation in the foraging cost arising from the risk of predation, and reflects the levels of fear a prey species perceives at different locations within its home range. In practice, the LOF maps habitat use as a result of perceived fear, which shows where bait or traps are most likely to be encountered and used by rodents. Several studies have linked perceived predation risk of foraging animals with quitting‐harvest rates or giving‐up densities (GUDs). GUDs have been used to reflect foraging behaviour strategies of predator avoidance, but to our knowledge very few papers have directly used GUDs in relation to pest management strategies. An opportunity for rodent control strategies lies in the integration of the LOF of rodents in EBRM methodologies. Rodent management could be more efficient and effective by concentrating on those areas where rodents perceive the least levels of predation risk. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献