A tour of computers: ideas and information     

Goodstein DL 《Science (New York, N.Y.)》1989,244(4900):90

  相似文献   

Bomb factories of the 21st century     

Marshall E 《Science (New York, N.Y.)》1989,243(4889):305

  相似文献   

Shuttle faces tough schedule in 1989     

Marshall E 《Science (New York, N.Y.)》1989,243(4893):884

  相似文献   

The archeology of capitalism: the recovery of meaning     

Zubrow E 《Science (New York, N.Y.)》1989,244(4906):861-863

  相似文献   

Authors' reply          下载免费PDF全文

Quine JP  Strunin L 《The Canadian veterinary journal. La revue veterinaire canadienne》1989,30(1):10-11

  相似文献   

Ontario. Iron storage disease (hemochromatosis) in a mynah bird          下载免费PDF全文

Sanford SE 《The Canadian veterinary journal. La revue veterinaire canadienne》1989,30(3):255

  相似文献   

Check-list for scientific names of common parasitic fungi. Series 3b: Fungi on bulbs: Amaryllidaceae and Iridaceae     

G. H. Boerema  Maria E. C. Hamers 《European journal of plant pathology / European Foundation for Plant Pathology》1989,95(Z3):1-29

This list is a continuation of Series 3a (Neth. J. Pl. Path. 94 (1988), Supplement 1), an account of the nomenclature of common parasitic fungi on bulbs as used in official publications of the Netherlands Society of Plant Pathology and the Netherlands Ministry of Agriculture and Fisheries. The selected names include one new species,Curvularia gladioli Boerema & Hamers, one new pathogenic form,Fusarium oxysporum f.sp.croci Boerema & Hamers, and one new combination,Sclerotium narcissi (Sacc.) Boerema & Hamers.A contribution towards the costs of publication provided by the Landbouw Export Bureau Fund, Wageningen, is gratefully acknowledged.  相似文献   

A review of models of landscape change   总被引：23，自引：1，他引：22  

William L. Baker 《Landscape Ecology》1989,2(2):111-133

Models of landscape change may serve a variety of purposes, from exploring the interaction of natural processes to evaluating proposed management treatments. These models can be categorized as either whole landscape models, distributional landscape models, or spatial landscape models, depending on the amount of detail included in the models. Distributional models, while widely used, exclude spatial detail important for most landscape ecological research. Spatial models require substantial data, now more readily available, via remote sensing, and more easily manipulated, in geographical information systems. In spite of these technical advances, spatial modelling is poorly developed, largely because landscape change itself is poorly understood.To facilitate further development of landscape models I suggest (1) empirical multivariate studies of landscape change, (2) modelling of individual landscape processes, (3) explicit study of the effect of model scale on model behavior, and (4) scaling-up results of studies, on smaller land areas, that have landscape relevance.  相似文献   

The detection and measurement of stray electrical leakages on dairy farms: effects on performance     

Dewes HF  Lowe MD  Bydder EL 《New Zealand veterinary journal》1989,37(3):117-121

Sources of stray electrical leakage from Power Supply Authority alternating current (AC), fence energiser pulses and randomly generated pulses and spikes on 55 dairy farms in the Waikato area were identified between December 1986 and March 1988. The electrical measurements were made using a specifically designed voltmeter able to detect voltages between 0.1V and 1500V, from single voltage spikes of two microseconds or greater duration from direct current (DC) as well as 50 Hz AC. Ninety-five sources of stray voltage were identified, and 53 per cent of properties had more than one source of >0.5V. The major source was from electric fence energisers. Rotary platform parlours were among the commonest sources of random or transient voltage spikes. Leakage of AC into one or other of the components of the milk transport system such as vat, plate cooler, milk lift pump and milk line was common. Owners acknowledged the improvements in milk production, reproductive performance and growth rate of calves after reduction of the exposure of dairy cattle to stray electrical leakage. A representative summary of five case records helps define the range of improvements that may possibly be achieved.  相似文献   

A survey of anthelmintic resistance on ten goat farms in the Manawatu region in 1988     

Scherrer AM  Pomroy WE  Charleston WA 《New Zealand veterinary journal》1989,37(4):148-149

A survey of anthelmintic resistance on ten goat farms was carried out. The criterion for resistance was a faecal egg count reduction (FECR) of <90 percent based on arithmetic means of 11 to 19 goats per group. It was found that nine of the ten farms harboured nematodes resistant to oxfendazole when used at 5mg/kg although on two of these, the FECR's were 89.2 percent and 89.8 percent. Post treatment larval cultures indicated Haemonchus, Ostertagia and Trichostrongylus were the resistant genera involved. On none of the ten farms was resistance to oral ivermectin at 0.2mg/kg detected.  相似文献