A survey of Libyostrongylus douglassi on ostrich farms in eastern Victoria     

C. BUTTON  NJ BARTON  PI VEALE  DJ OVEREND 《Australian veterinary journal》1993,70(2):76-76

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Dicoumarol toxicity in cattle associated with ingestion of silage containing sweet vernal grass (Anthoxanthum odoratum)     

DJ RUNCIMAN  AM LEE  KFM REED  JR WALSH 《Australian veterinary journal》2002,80(1):28-32

A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass ( Anthoxanthum odoratum ). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis.  相似文献   

Serological characterisation of Haemophilus parasuis isolates from Australian pigs   总被引：2，自引：0，他引：2  

PJ BLACKALL  VJ RAPP-GABRIELSO†  DJ HAMPSON‡ 《Australian veterinary journal》1996,73(3):93-95

A total of 31 isolates of Haemophilus parasuis obtained from Australian pigs were serotyped by the Kielstein-Rapp-Gabrielson scheme. The isolates were assigned to serovar 1 (1 isolate), serovar 2 (1 isolate), serovar 4 (4 isolates), serovar 5 (7 isolates), serovar 9 (2 isolates), serovar 10/7 (4 isolates), serovar 12 (1 isolate) and serovar 13 (6 isolates). The remaining 5 isolates could not be assigned to a serovar. Two different serovars (5 and 13) were detected in one herd. The only 2 isolates obtained from clinically normal pigs (from the same herd) were serovar 9. The common serovars were isolated from pigs with pneumonia as well as from pigs with conditions of the Glässer's disease type. The serological heterogeneity amongst Australian isolates of H parasuis has important implications for the use of vaccines to control Glässer's disease.  相似文献   

Effects on nutrients and on grain quality in spring wheat crops grown under elevated CO₂ concentrations and stress conditions in the European, multiple-site experiment ‘ESPACE-wheat’     

A. Fangmeier  L. De Temmerman  L. Mortensen  K. Kemp  J. Burke  R. Mitchell  M. van Oijen  H. -J. Weigel 《European Journal of Agronomy》1999,10(3-4):215-229

Nutrient element concentrations and grain quality were assessed in spring wheat grown under elevated CO₂ concentrations and contrasting levels of tropospheric ozone at different nitrogen supply rates at several European sites. Carbon dioxide enrichment proved to affect nutrient concentrations in a complex manner. In green leaves, all elements (with exception of phosphorus and iron) decreased. In contrast, effects on the element composition of grains were restricted to reductions in nitrogen, calcium, sulphur and iron. Ozone exposure resulted in no significant effects on nutrient element concentrations in different tissues in the overall analysis. The nitrogen demand of green tissues was reduced due to CO₂ enrichment as shown by reductions in the critical leaf nitrogen concentration and also enhanced nitrogen use efficiency. Reductions in the content of ribulose-bisphosphate carboxylase/oxygenase and repression of the photorespiratory pathway and reduced nitrogen allocation to enzymes driving the photosynthetic carbon oxidation cycle were chiefly responsible for this effect. Thus, nitrogen acquisition by the crop did not match carbon acquisition under CO₂ enrichment. Since crop nitrogen uptake from the soil was already completed at anthesis, nitrogen allocated to the grain after anthesis originated from vegetative pools—causing grain nitrogen concentrations to decrease under CO₂ enrichment (on average by 15% when CO₂ concentrations increased from 360 to 680 μmol mol⁻¹). Correspondingly, grain quality was reduced by CO₂ enrichment. The Zeleny value, Hagberg value and dry/wet gluten content decreased significantly with increasing [CO₂]. Despite the beneficial impact of CO₂ enrichment on growth and yield of C₃ cereal crops, declines in flour quality due to reduced nitrogen content are likely in a future, [CO₂]-rich world.  相似文献   

Cell-cell signaling and movement by the floral transcription factors LEAFY and APETALA1     

Sessions A  Yanofsky MF  Weigel D 《Science (New York, N.Y.)》2000,289(5480):779-782

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Imaging of intermittency in ripple-wave turbulence     

WB Wright  R Budakian  DJ Pine  SJ Putterman 《Science (New York, N.Y.)》1997,278(5343):1609-1612

The dynamics of a fluid surface filled with high-amplitude ripples were studied with a technique (diffusing light photography) that resolves the height at all locations instantaneously. Even when nonlinearities are strong enough to generate a (Kolmogorov) cascade from long wavelength (where energy is input) to shorter wavelength, the resulting turbulent state contains large coherent spatial structures. The appearance of these structures in a thermal equilibrium state (with the same average energy) would be highly improbable.  相似文献   

Two gap genes mediate maternal terminal pattern information in Drosophila   总被引：8，自引：0，他引：8  

D Weigel  G Jürgens  M Klingler  H J?ckle 《Science (New York, N.Y.)》1990,248(4954):495-498

In Drosophila three maternal pattern organizing activities, the anterior, the posterior, and the terminal, establish the anterior-posterior body pattern of the embryo by initiating the spatially restricted activities of the gap class of zygotic segmentation genes. The activities of tailless (tll) and the newly identified gap gene huckebein (hkb) are specifically involved in mediating the maternal terminal information at the posterior end of the blastoderm embryo.  相似文献   

Predatory Dinosaurs from the Sahara and Late Cretaceous Faunal Differentiation     

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   

Growth responses and foliar sensitivities of native herbaceous species to ozone exposures     

E. Bergmann  J. Bender  H. J. Weigel 《Water, air, and soil pollution》1995,85(3):1437-1442

This paper reports on open-top chamber studies investigating the effects of different O₃ exposures on native herbaceous plant species. Plants were grown up from seeds, potted into natural soils and exposed to near-ambient O₃ levels during one growing season. A wide range of visible symptoms was apparent during the exposures. Species such as Rumex obtusifolius, Senecio vulgaris or Sonchus asper showed leaf colorations (e.g. reddish pigmentation) that probably indicate a non-specific stress response. In other species especially of the genera Malva and Cirsium the symptoms produced by O₃ appeared to be similar to those characteristic for O₃-specific foliar injury (stippling, flecking). In almost all species tested, O₃ caused premature leaf senescence, which was sometimes associated with premature leaf abscission. However, earlier senescence did not necessarily result in changes in plant growth. Of all species tested, Malva sylvestris was found to be the most sensitive in terms of growth reduction and lower seed production.  相似文献   

Prevalence of pseudorabies virus infection and associated infections in six large swine herds in Illinois.     

W F Hall  R M Weigel  A M Siegel  J F Wiemers  J R Lehman  A C Taft  J F Annelli 《Journal of the American Veterinary Medical Association》1991,198(11):1927-1931

Sera were collected from 6 large farrow-to-finish swine herds infected with pseudorabies virus (PRV) in Illinois. All herds were participating in the Large Herd Cleanup Study, a USDA-initiated project to evaluate the feasibility of eradicating pseudorabies from large farms (greater than 400 sows) by use of a combination of vaccination and management changes. Herd size ranged between 425 and 1,500 breeding females. Between April and July 1990, sera for measurement of PRV antibodies were obtained from 113 to 156 sows and 112 to 162 finishing pigs (body weight greater than 70 kg)/herd. Duplicate sera from 30 sows and 30 market-weight pigs/herd were obtained for measurement of serum antibodies to the following associated organisms: swine influenza virus, transmissible gastroenteritis virus, encephalomyocarditis virus, Actinobacillus pleuropneumoniae, Eperythrozoon suis, and 6 serovars of Leptospira interrogans. Prevalence of PRV antibodies attributable to field virus infection ranged between 53.8 and 100% for sows and between 0.7 and 97.3% for finishing pigs, as determined by the appropriate differential test for the vaccine being used on each farm. In only 1 herd, PRV seroprevalence was increased with higher sow parity. For associated infections, the risk of seropositivity attributable to PRV was not significant (for most infections) on all farms and varied among farms. Thus, pseudorabies did not appear, in general, to increase susceptibility to infection with other disease agents.  相似文献