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71.
Polarized and unpolarized neutron scattering was used to measure the wave vector- and frequency-dependent magnetic fluctuations in the normal state (from the superconducting transition temperature, Tc = 35 kelvin, up to 350 kelvin) of single crystals of La1.86Sr0.14CuO4. The peaks that dominate the fluctuations have amplitudes that decrease as T-2 and widths that increase in proportion to the thermal energy, kBT (where kB is Boltzmann's constant), and energy transfer added in quadrature. The nearly singular fluctuations are consistent with a nearby quantum critical point. 相似文献
72.
A leafy strain of timothy and of perennial ryegrass showed no significant reductions in seed yields following grazing at different dates from October to January, when extra nitrogen was applied.
Spring and winter + spring grazing, together with extra nitrogen, significantly reduced the seed yield of S50 timothy for three successive harvest years.
Perennial ryegrass S101 showed no reduction after spring or winter + spring grazing when defoliation was made not later than mid-April, but when grazing was delayed until May and drought occurred there was a significant reduction in seed yield. 相似文献
Spring and winter + spring grazing, together with extra nitrogen, significantly reduced the seed yield of S50 timothy for three successive harvest years.
Perennial ryegrass S101 showed no reduction after spring or winter + spring grazing when defoliation was made not later than mid-April, but when grazing was delayed until May and drought occurred there was a significant reduction in seed yield. 相似文献
73.
74.
R Jamaludin PJ Blackall MF Hansen S Humphrey M Styles 《New Zealand veterinary journal》2013,61(3):203-207
AIMS: To examine pigs at slaughter in New Zealand for the presence of Pasteurella multocida, and to determine for isolates, their biochemical profiles, somatic and capsular types, and the presence or absence of the HSB and toxA genes, associated with haemorrhagic septicaemia (HS) and progressive atrophic rhinitis (PAR), respectively. METHODS: Swabs from 173 lungs, 158 palatine tonsils and 82 nasal passages of pigs at two abattoirs in New Zealand were cultured for P. multocida using conventional techniques, and isolated colonies were subjected to biochemical tests for identification of biovars. Somatic serotyping was conducted using an agar gel immunodiffusion (AGID) test. Polymerase chain reaction (PCR) assays were used to confirm phenotypic identification of colonies using species-specific primers, capsule type using serogroup-specific primers and multiplex PCR, and to test for the presence of HSB and toxA genes. RESULTS: Pasteurella multocida was isolated from 11/173 (6.4%) lung, 32/158 (20.2%) palatine tonsil and 5/82 (6.1 %) nasal swab samples, a total of 48 isolates from 413 samples (11.6%). Isolation rates per farm ranged from 1–53% of tissue samples collected from pigs 5–6 months of age. On phenotypic characterisation, isolates were allocated to seven main biovars, viz 1, 2, 3, 5, 9, 12, and a dulcitol-negative variant of Biovar 8, the majority (30/48) being Biovar 3. Of the 42 isolates for which somatic serotyping was conducted, 10% were Serovar 1, 79% were Serovar 3, 2% were Serovar 6,1, 2% were Serovar 12, and 7% could not be typed. All 48 isolates were confirned as P. multocida using a species-specific PCR. In the capsular multiplex PCR, 92% of isolates were Capsular (Cap) type A, 2% were Cap D, and 6% could not be typed. None of the samples were positive for the HSB or toxA genes. CONCLUSION: Serovars or capsular types of P. multocida associated with HS or PAR in pigs were not detected. Establishment of species-specific, capsular and toxin PCR assays allowed the rapid screening of isolates of P. multocida, while serotyping provided an additional tool for epidemiological and tracing purposes. 相似文献
75.
SUMMARY Chronic fluoride toxicosis caused lameness, dental lesions and illthrift in an extensive beef cattle herd in northern Australia. Up to 15% of the herd was lame and the disease forced the culling of large numbers of cows. The source of fluoride was fertiliser-grade monoammonium and diammonlum phosphate fed as part of a mineral supplement. Large quantities of mineral supplement were provided to the cattle because lameness was attributed to phosphorus deficiency, which is endemic in the area. Most lameness developed in the late dry season in the post-lactation phase. Severe lameness was caused by fractured pedal bones. 相似文献
76.
Salmonella enteritidis PT4 infection in specific pathogen free hens: influence of infecting dose. 总被引:2,自引:0,他引:2
The period during which specific pathogen free hens, infected by direct introduction into the crop of either 10(3), 10(6) or 10(8) cells of Salmonella enteritidis PT4, excreted the organism in faeces was closely related to the size of the inoculum, with the birds excreting for mean periods of 3.4, 16.4 and 36.8 days, respectively. The production of either IgG or IgM was also dose related with the birds which received 10(3) cells having lower antibody levels than those in the other two groups. In contrast, there was no relationship between the contamination of egg contents and either antibody status, faecal excretion, or the dose administered. 相似文献
77.
KINETICS OF DICHLOBENIL DEGRADATION IN SOIL 总被引:2,自引:0,他引:2
Summary. The rates of degradation of dichlobenil (2,6-dichlorobenzonitrile) in soil were determined at 67 and 267°C. The degradation followed first-order kinetics but at 67°C this occurred after an initial lag period of 10 weeks. The half-lives were 28 weeks (+ 10 weeks lag) at 6.7°C and 19 weeks at 26.7°C. The activation energy for the decomposition was the relatively low value of 3.57 kcal/mole, indicating that the degradation of dichlobenil is not as markedly affected by temperature as that of many other herbicides. The only detectable metabolite was 2,6-dichlorobenzamide, a compound that should have a substantially lower vapour pressure and a higher affinity for surfaces than the parent compound. Cinétique de la dégradation du dichlobénil dans le sol Résumé. Les taux de dégradation du dichlobénil (2,6-dichlorobenzonitrile) dans le sol ont été détermines à 6,7 et 26,7°C. La déSgradation suivit une loi cinétique du premier ordre, mais à 6,7°C ceci se produisit aprés une période initiate de latence de 10 semaines. Les demi-vies furent de 28 semaines (plus 10 semaines de latence) a 6,7°C et 19 semaines à. 26,7°C. L'énergie d'activation pour la décomposition s'établit à la valeur relativement faible de 3,57 kcal/mole; ceci indique que la dégradation du dichlobénil n'est pas aussi profondément affcctée par la température quc celle de beaucoup d'autres herbicides. Le seul métabolite detectable fut le 2,6-dichlorobenzamide, composé qui devrait avoir une pression de vapeur notablement plus faible et une affinité plus grande pour les surfaces que le composé apparenté. Kinetik des Dichlohenil-Abbaus im Boden Zusammenfassung. Es wurde die Abbaugeschwindigkeit von Dichlobenil (2,6-Dichlorbenzonitril) im Boden bei 6,7°C und 26,7°C bestinimt. Der Abbau entsprach einer Reaktion erster Ordnung. Bei 6,7°G setzte der Abbau nach einer lag-Phase von 10 Wochen ein. Die Halbwertzeiten betrugen 28 Wochen (+10 Wochen lag-Phase) bei 6,7°C und 19 Wochen bei 26,7°C. Die Aktivierungsenergie war verhältnisniässig niedrig und betrug 3,57 Kcal/Mol und zeigt, dass der Abbau von Dichlobenil durch Temperatur nicht so stark beeinflusst wird wie bei vielen anderen Herbiziden. Der einzige nachweisbare Metabolit war 2,6-Dichlorbenzamid, der einen wcsentlich nieddgeren Dampfdruck und eine grössere Affinität gegenüber Oberfiächen haben dürfte als die ursprüngliche Verbindung. 相似文献
78.
The present study was carried out to examine whether pentoxifylline administration to horses premedicated with frusemide would attenuate the exercise-induced pulmonary arterial, capillary and venous hypertension to a greater extent than frusemide alone, thereby affecting the occurrence of exercise-induced pulmonary haemorrhage (EIPH). Using established techniques, we determined right heart and pulmonary vascular pressures in 6 healthy, sound Thoroughbred horses at rest and during exercise performed at maximal heart rate at a workload of 14 m/s on 3.5% uphill grade in the control (no medications), frusemide (250 mg i.v., 4 h pre-exercise)-control, and the frusemide (250 mg i.v., 4 h pre-exercise) + pentoxifylline (8.5 mg/kg bwt i.v., 15 min preexercise) treatments. Sequence of the 3 treatments was randomised for every horse and 7 days were allowed between them. In the control study, galloping at 14 m/s on 3.5% uphill grade elicited significant right atrial as well as pulmonary arterial, capillary and venous hypertension and all horses experienced EIPH as detected by the presence of fresh blood in the trachea on endoscopic examination. Frusemide administration was not attended by changes in heart rate at rest or during exercise. Although in the frusemide-control experiments, a significant reduction in mean pulmonary arterial, capillary and wedge pressures was observed both at rest and during galloping at 14 m/s on 3.5% uphill grade, all horses still experienced EIPH. Pentoxifylline administration to standing horses premedicated with frusemide caused nervousness, muscular fasciculations, sweating and tachycardia. Although these symptoms had largely abated within 15 min, there were no significant changes in the right atrial or pulmonary vascular pressures. Exercise in the frusemide + pentoxifylline experiments also caused significant right atrial as well as pulmonary arterial, capillary and venous hypertension, but these data were not found to be significantly different from the frusemide-control experiments. All horses in the frusemide + pentoxifylline experiments also experienced EIPH. In conclusion, our data indicate that pentoxifylline (8.5 mg/kg bwt i.v., 15 min pre-exercise) is ineffective in modifying the pulmonary haemodynamic effects of frusemide in exercising horses. It should be noted, however, that we did not examine whether erythrocyte plasticity was altered by the administration of pentoxifylline. Since the intravascular force exerted onto the blood-gas barrier of exercising horses premedicated with frusemide remained unaffected by pentoxifylline administration, it is concluded that concomitant pentoxifylline administration is unlikely to offer additional benefit to horses experiencing EIPH. 相似文献
79.
80.