Studies on the Health of Beech Trees in Surrey, England: Relationship between Winter Canopy Assessment by Roloff's Method and Twig Analysis     

STRIBLEY  G. H. 《Forestry》1993,66(1):1-26

Trees and saplings of all sizes (total 229) were studied atthree amenity sites in Surrey representing mixed woodland, beechhigh forest and open parkland. Roloff's winter assessment ofthe twig pattern of growth demonstrated an underlying differencebetween the sites, which was consistent with an associationbetween greater deterioration and more exposure to climate extremesand pollutants. Trees showed deterioration with age but prematureageing was seen in 35–50-year-old parkland trees. Withinthe woodland the more exposed trees had worse scores. Quantitative twig analysis was carried out on twigs from theupper canopy of 19 trees and saplings. In the most severelysuppressed trees yearly growth declined from the 1976 drought.Subsidiary shoot development was markedly reduced in such treesand there were high numbers of distorted and acute angled shoots.The latter two characteristics increased with age with younghealthy trees having very few of these types of shoots, buttwo 35-year-old trees in open parkland showed premature ageingwith larger numbers of such shoots. Twig analysis defined categories of twig pattern according toage and deterioration levels. There was generally good correlationbetween these categories and the Roloff twig canopy score beforeanalysis or with canopy scores of similar sized neighbours.Objective criteria suggested for future studies were: (1) measurementof annual primary shoot growth; (2) total secondary shoot lengthrelative to a standard primary shoot length; (3) mean numberof subsidiary shoots per year; and (4) proportion of shootsgrowing at 40° or less.  相似文献   

Testing the effectiveness of foot-and-mouth disease vaccines: the relationship between test infection results and corresponding neutralization titers of vaccinated cattle     

H J Bengelsdorff 《Berliner und Münchener tier?rztliche Wochenschrift》1989,102(6):193-198

In the course of vaccine controls, the potency of 25 foot-and-mouth disease (FMD) vaccines was tested quantitatively in parallel in cattle using the intradermal infection and the determination of the SN titres. More than 95% of the vaccinated cattle with SN titres of greater than 1:20 were protected from generalized FMD, regardless of the virus type tested. 61.5% of the vaccinated cattle with SN titres less than or equal to 1:20 were not protected and developed generalized FMD. Comparison of the PD50 values calculated from the results of the intradermal infection and the corresponding SN titres (minimum protection titre greater than 1:20) showed that the results were in complete agreement in 56% of the tested vaccines. In a further 32% of vaccines, the PD50 calculated from the SN titre was slightly below that for the intradermal infection, in the remaining 12% it was somewhat above. The possibility of using the minimum titre determination for testing a vaccine and the significance of this titre as an expression of protection by vaccination are discussed.  相似文献   

Chronic renal failure associated with bilateral nephroliths and ureteroliths in a two-year-old Thoroughbred colt   总被引：1，自引：0，他引：1  

W D Hope  J H Wilson  D A Hager  M R Garry  M B Calderwood-Mays 《Equine veterinary journal》1989,21(3):228-231

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Clinical care of the elderly cat and dog: Proceedings of a symposium on clinical conditions in the older dog and cat     

A. H. Sparkes 《The Journal of small animal practice》1989,30(10):578-578

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Parosteal osteosarcoma of the mandible in a dog     

J D Brogdon  A H Brightman  L C Helper  S A Mclaughlin  A L Johnson 《Journal of the American Veterinary Medical Association》1989,194(8):1079-1081

A mandibular parosteal osteosarcoma was diagnosed in a 7-year-old Collie with prolapse of the third eyelid. Diagnosis was made by histologic evaluation of a mass removed by surgical excision. The dog was euthanatized because of local recurrence of the tumor, with metastasis to the lungs. Parosteal osteosarcomas are rarely reported in dogs and usually involve long bones in human beings.  相似文献   

Detection of mycoplasmas in experimentally-infected bull sperm     

A Richter  H Pfützner 《Archiv fuer experimentelle veterinaermedizin》1989,43(5):721-724

Bull sperm pellets experimentally infected with various concentrations of Mycoplasma (M.) bovis, M. bovigenitalium, and M. californicum were stored several months at -196 degrees C and were subsequently tested for mycoplasmas, using different methods and culturing media. M. bovis was reliably identified by laboratory diagnosis up to a concentration of 10(2) cfu/pellet. M. bovigenitalium and M. californicum were found to make higher demands on the quality of culturing substrates. Recommended are 1-h broth incubation and 5-d broth breeding.  相似文献   

MYSTERIOUS ACOUSTIC PHENOMENA IN YELLOWSTONE NATIONAL PARK     

Smith HM 《Science (New York, N.Y.)》1926,63(1641):586-587

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THE VENOMOUS EFFECTS OF SOME ARIZONA SCORPIONS     

Stahnke HL 《Science (New York, N.Y.)》1938,88(2277):166-167

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TECHNICAL UNIVERSITY DEGREES     

Thurston RH 《Science (New York, N.Y.)》1899,10(257):820

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A THIRD ORDER RAINBOW     

Farwell HW 《Science (New York, N.Y.)》1914,40(1034):595-596

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