Bacterial Diseases of Cassava     

J. F. Bradbury 《国际虫害防治杂志》2013,59(1)

Abstract

Recent developments on the identities of the causal agents of bacterial diseases of cassava throughout the world are discussed.  相似文献   

Enterovirulence of enterotoxigenic Bacteroides fragilis in gnotobiotic pigs.   总被引：6，自引：0，他引：6  

J R Duimstra  L L Myers  J E Collins  D A Benfield  D S Shoop  W C Bradbury 《Veterinary pathology》1991,28(6):514-518

A porcine isolate of enterotoxigenic Bacteroides fragilis colonized the intestinal tract and caused watery, nonhemorrhagic diarrhea when given orally to 12, 1- to 2-day-old gnotobiotic pigs. Diarrhea occurred 2 to 3 days post-inoculation and continued throughout the 4 to 6 day post-inoculation period. Diarrheic pigs became mildly anorexic and dehydrated. They developed intestinal lesions characterized by swelling, vacuolation, and exfoliation of enterocytes, and crypt hyperplasia throughout the large intestine and, to a lesser extent, in the distal small intestine. Bacterial adherence to, or invasion of, the intestinal mucosa was not detected. A porcine isolate of nonenterotoxigenic B. fragilis was administered orally to six control pigs. The isolate colonized the intestinal tract, but the pigs did not develop clinical disease or intestinal lesions. The pathogenetic mechanism of the disease may involve mediation by a soluble enterotoxin (or toxins) elaborated by B. fragilis.  相似文献   

Unusual osteochondral lesions of the talus in a horse     

CM SIMPSON  JM LUMSDEN 《Australian veterinary journal》2001,79(11):752-755

A 2-year-old Thoroughbred gelding was evaluated for a grade 3 out of 5 unilateral hind limb lameness. Flexion of the right hock and stifle joints (spavin test) exacerbated the lameness. Response to intra-articular and perineural anaesthesia isolated the source of lameness to the tarsocrural area, despite an absence of tarsocrural joint effusion. Routine radiographic examination of the hock did not reveal any significant abnormalities. Skeletal nuclear scintigraphic evaluation revealed a focal region of increased bone activity in the proximal medial trochlear ridge of the talus. Flexed lateromedial radiographic views identified three discrete semicircular lytic lesions at the proximal articular margin of the medial trochlear ridge of the talus. Conservative management of the lesions was associated with a successful return to racing. The location and appearance of the osteochondral lesions of this report have not been previously reported and may be a manifestation of developmental orthopaedic disease and abnormal endochondral ossification. Nuclear scintigraphy and flexed lateromedial radiographic views facilitated identification of the lesions. This radiographic view is recommended when lameness is isolated to the tarsocrural joint and standard radio-graphic projections fail to identify a cause.  相似文献   

Metathesis of Alkanes Catalyzed by Silica-Supported Transition Metal Hydrides     

V Vidal  A Theolier  J Thivolle-Cazat  JM Basset 《Science (New York, N.Y.)》1997,276(5309):99-102

The silica-supported transition metal hydrides (=Si-O-Si=)(=Si-O-)2Ta-H and (=Si-O-)xM-H (M, chromium or tungsten) catalyze the metathesis reaction of linear or branched alkanes into the next higher and lower alkanes at moderate temperature (25degrees to 200degreesC). With (=Si-O-Si=)(=Si-O-)2Ta-H, ethane was transformed at room temperature into an equimolar mixture of propane and methane. Higher and lower homologs were obtained from propane, butane, and pentane as well as from branched alkanes such as isobutane and isopentane. The mechanism of the step leading to carbon-carbon bond cleavage and formation likely involves a four-centered transition state between a tantalum-alkyl intermediate and a carbon-carbon final sigma-bond of a second molecule of alkane.  相似文献   

Spatial Variability of Turbulent Mixing in the Abyssal Ocean   总被引：3，自引：0，他引：3  

KL Polzin  JM Toole  JR Ledwell  RW Schmitt 《Science (New York, N.Y.)》1997,276(5309):93-96

Ocean microstructure data show that turbulent mixing in the deep Brazil Basin of the South Atlantic Ocean is weak at all depths above smooth abyssal plains and the South American Continental Rise. The diapycnal diffusivity there was estimated to be less than or approximately equal to 0.1 x 10(-4) meters squared per second. In contrast, mixing rates are large throughout the water column above the rough Mid-Atlantic Ridge, and the diffusivity deduced for the bottom-most 150 meters exceeds 5 x 10(-4) meters squared per second. Such patterns in vertical mixing imply that abyssal circulations have complex spatial structures that are linked to the underlying bathymetry.  相似文献   

Ecology. Are U.S. coral reefs on the slippery slope to slime?     

Pandolfi JM  Jackson JB  Baron N  Bradbury RH  Guzman HM  Hughes TP  Kappel CV  Micheli F  Ogden JC  Possingham HP  Sala E 《Science (New York, N.Y.)》2005,307(5716):1725-1726

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Coral reefs under rapid climate change and ocean acidification   总被引：13，自引：0，他引：13  

Hoegh-Guldberg O  Mumby PJ  Hooten AJ  Steneck RS  Greenfield P  Gomez E  Harvell CD  Sale PF  Edwards AJ  Caldeira K  Knowlton N  Eakin CM  Iglesias-Prieto R  Muthiga N  Bradbury RH  Dubi A  Hatziolos ME 《Science (New York, N.Y.)》2007,318(5857):1737-1742

Atmospheric carbon dioxide concentration is expected to exceed 500 parts per million and global temperatures to rise by at least 2 degrees C by 2050 to 2100, values that significantly exceed those of at least the past 420,000 years during which most extant marine organisms evolved. Under conditions expected in the 21st century, global warming and ocean acidification will compromise carbonate accretion, with corals becoming increasingly rare on reef systems. The result will be less diverse reef communities and carbonate reef structures that fail to be maintained. Climate change also exacerbates local stresses from declining water quality and overexploitation of key species, driving reefs increasingly toward the tipping point for functional collapse. This review presents future scenarios for coral reefs that predict increasingly serious consequences for reef-associated fisheries, tourism, coastal protection, and people. As the International Year of the Reef 2008 begins, scaled-up management intervention and decisive action on global emissions are required if the loss of coral-dominated ecosystems is to be avoided.  相似文献   

Survey of field outbreaks of avian infectious laryngotracheitis in England and Wales.     

C S Hughes  R M Gaskell  J M Bradbury  F T Jordan  R C Jones 《The Veterinary record》1991,129(12):258-260

Field outbreaks of infectious laryngotracheitis in commercial chicken flocks in England and Wales between 1985 and 1988 were investigated. Material from 49 outbreaks was submitted to Liverpool University, and virus was isolated from 17 of them. The results of a questionnaire on each outbreak are described. Generally, the disease was of moderate severity, and mainly affected laying flocks; it occurred in birds of a wide age range but most of the outbreaks were in birds between 10 and 20 weeks of age. The disease was not seen more frequently at any particular time of the year, and there was no evidence of a common source of infection. Three of the affected flocks had recently been moved and were beginning to lay; these stresses may have caused the re-excretion of latent virus.  相似文献   

Cost-benefit analysis and investment appraisal in relation to pest control measures     

Frank R. Bradbury  Brian J. Loasby 《Pest management science》1977,8(4):366-376

A distinction is drawn between cost-benefit analysis and investment appraisal. Both are methods for evaluating projects, with cost-benefit analysis looking at proposals from the angle of the larger community in contrast to investment appraisal which looks at them from the individual, or firm, point of view. The time value of money is examined and also the treatment by cost-benefit analysis of social values and other elements outside the purview of investment appraisal, the so-called externalities or spillovers. Cost-benefit analysis of pest control measures is shown to depend heavily on analysis of the complexities and interactions of the biological/biochemical systems involved. This leads to the conclusion that the main thrust of cost-benefit studies in the pesticide field is to improve our understanding of pest problems and thereby to improve the efficiency of pest control measures, to the benefit of both the industry and the public.  相似文献   

Diagnostic methods used to monitor an outbreak of babesiosis (Babesia bovis) in a herd of feral cattle in New Caledonia     

T Hüe  M Graille  A Mortelecque  D Desoutter  JM Delathière  C Marchal  M Teurlai  N Barré 《Australian veterinary journal》2013,91(6):254-258

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