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Forecasting timber production many years in advance has becomea problem of considerable importance in this country becauseof the need to co-ordinate the rapid increase in productionwith the establishment of new timber-using industries. Thispaper describes a change in emphasis in state forest WorkingPlan Inventory methods employed in the predominantly young,coniferous forests of Great Britain and is a development ofthe methods described in a previous paper (Problems ofYield Control and Inventory in British ForestryD.R. Johnston, 1960, Forestry, 33, 1936). Total enumerationof the growing stock is no longer the main objective of forestinventory and the new approach is directed towards (a) assessmentof the productive potential of each subcompartment and (b) theintensive enumeration of sample or index subcompartmentsinitially and at each re-enumeration as a check on growth predictionsand yield control. 相似文献
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New nuclear magnetic resonance data lead to a completely unambiguous proof that the predominant tautomeric form of 1-methylcytosine is the amino form and that in acid solution the molecule protonates at 3-N. The close similarity of the nuclear magnetic resonance spectra of this compound to the spectra of the cytosine nucleosides indicates that these structures also exist in the nucleosides. These conclusions are reached on the basis of the spectra of analogs labeled with N15 and of the proton spin decoupling measurements made at low temperature. 相似文献
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A light and electron microscope study of epitheliocystis in juvenile steelhead trout, Salmo gairdneri Richardson 总被引:1,自引:0,他引:1
Abstract. Ultrastructural analysis of epitheliocystis organisms from gills of anadromous juvenile steelhead trout, Salmo gairdneri Richardson, revealed the presence of several distinct forms. Two oval infectious organisms resembled previously described agents and had chlamydia-like characteristics. One form had a distinct oval head region from which a tail-like structure projected. These prokaryotic forms have an ultrastructural appearance which has not been described in previous reports of epitheliocystis. Morphological analyses of gill epithelial cells of S. gairdneri suggest that each cyst remains contained within the cytoplasm of a single host cell. 相似文献
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Nasopharyngeal cryptococcosis 总被引:1,自引:0,他引:1
R MALIK P MARTIN DI WIGNEY DB CHURCH W BRADLEY CR BELLENGER WA LAMB VR BARRS S FOSTER S HEMSLEY PJ CANFIELD DN LOVE 《Australian veterinary journal》1997,75(7):483-488
Naturally occurring cryptococcosis in five cats, a dog and a koala is described. Involvement of the nasopharynx was documented in all patients, and nasopharyngeal mass lesions accounted for the major presenting complaints in four. Signs referable to nasopharyngeal disease included snoring, stertor, inspiratory dyspnoea and aerophagia. Diagnoses were made by caudal rhinoscopy using a retroverted flexible endoscope, vigorous orthograde flushing with saline, or at necropsy. Concurrent cryptococcal rhinitis was present in all cases, although involvement appeared limited to the caudal nasal cavity in most cases. Typical signs of nasal cavity disease, such as sneezing and nasal discharge, were often absent. Treatment of nasopharyngeal cryptococcosis should include physical dislodgement or debulking of lesion(s) to provide immediate alleviation of upper airway obstruction, followed by systemic antifungal therapy to eliminate residual infection from the nasal cavity. Infections caused by Cryptococcus neoformans var gattii accounted for a disproportionately large number of these cases. 相似文献
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BRADLEY R. JACKMAN DVM MS GARY M. BAXTER VMD MS DIPIOMATE ACVS RICHARD E. DORAN DVM MS Dipiomate ACVS DOUGLAS ALLEN DVM MS Dipiomate ACVS ANDREW H. PARKS MA VET MB Dipiomate ACVS 《Veterinary surgery : VS》1993,22(4):285-288
The medical records of 57 horses that had palmar digital neurectomy performed between 1984 and 1990 were reviewed. Neurectomies were performed either by transection and elec-trocoagulation (47 horses) or by the guillotine technique (10 horses). Middle-aged geldings, Quarter Horses, and Thoroughbreds were significantly over-represented when compared with the hospital population. Horses used as hunter/jumpers also appeared to be over-represented. Complications occurred in 17 (34%) of the 50 horses for which follow-up information was obtained. Recurrence of heel pain was the most common complication (14 horses). Palpable painful neuromas were detected in three horses. One year after neurectomy, 74% of the horses were sound; this decreased to 63% after 2 years. 相似文献
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Following the Chernobyl accident in April 1986 137 Cs was detected in samples of grass collected at AGRI, North Wyke, Devon, UK. Samples of grass from permanent and reseeded swards under uniform management were taken on three occasions. The 137 Cs content of the samples was assessed as both Bq kg-1 of sample and Bq m-2 , Samples taken from the same site in 1985 were used as a control group; these contained no measurable 137 Cs. The samples taken on 8 May 1986 had a 137 Cs content of approximately 30 Bq kg-1 ; by 31 July 1986 the content had dropped to 1% of this value. The permanent pasture initially showed a higher level of 137 Cs than the reseeded sward. Analysis of soil cores from the sampling area showed a much higher level of 137 Cs than that found in the herbage. This was attributed to the atmospheric testing of nuclear devices in the early 1960s: the short-lived 137 Cs isotope was found in the 1986 herbage samples but not in the soil cores. 相似文献
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C. T. DOUGHERTY N. W. BRADLEY L. M. LAURIAULT J. E. ARIAS P. L. CORNELIUS 《Grass and Forage Science》1992,47(3):211-219
Herbage allowance is one of the important pasture factors in the determination of intake by grazing livestock. Ingestive behaviour of 12 adult Angus cows (Bos taurus) was measured over a range of allowances (0·25 to 0·72 kg dry matter (DM) per 100 kg live weight (LW) for a 1-h period) of vegetative tall fescue (Festuca arundinacea Schreb.). A balanced change-over design was used to estimate direct, residual and permanent effects of herbage allowance on rate of DM intake, rate of biting and herbage DM intake per bite. In Experiment 1, herbage DM intake per meal increased linearly from 0·68 to 1·72 kg (100 kg LW)?1 as DM allowance increased from 0·25 to 0·72 kg (100 kg LW)?1 h?1. Cows grazed at ·30 kg (100 kg LW)?1 h?1 and stopped grazing when the sward was reduced to a height about 10 to 12 cm above the soil surface, approximately defined by the tops of pseudostems. In Experiment 2, herbage DM intake rates of 0·29, 0·47 and 0·42 kg (100 kg LW)?1 h?1 were recorded as cows grazed allowances of 0·43, 0·70 and 0·90 kg (100 kg LW)?1 h?1 for most of the 1-h grazing period. Limiting herbage DM allowances in Experiment 2 were associated with small reductions in rate of biting and herbage DM intake per bite as allowance declined. Sward DM density (>5 cm) was an important variable in the determination of herbage DM intake rates at lower herbage allowances. 相似文献