Mineral testing--the approach depends on what you want to find out     

Clark RG  Ellison RS 《New Zealand veterinary journal》1993,41(2):98-100

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Nonveterinarians providing "professional" services?          下载免费PDF全文

Graham G 《The Canadian veterinary journal. La revue veterinaire canadienne》1993,34(11):645

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Malignant catarrhal fever in a swamp buffalo (Bubalus bubalis) calf in New Zealand     

Hill FI  Arthur DG  Thompson J 《New Zealand veterinary journal》1993,41(1):35-38

Malignant catarrhal fever was diagnosed in a newly imported swamp buffalo calf. This disease is prevalent in deer and cattle in New Zealand and causes sporadic losses in these species. The disease is recognised as a problem in buffaloes overseas and this paper records the first case in a swamp buffalo in New Zealand.  相似文献   

The role of autotoxins from root residues of the previous crop in the replant disease of asparagus     

W. J. Blok  G. J. Bollen 《European journal of plant pathology / European Foundation for Plant Pathology》1993,99(3):29-40

Replant disease is a common phenomenon in asparagus growing in the Netherlands. It is distinct from the decline phenomenon reported from many other asparagus producing area’s. The involvement of autotoxins from root residues of former asparagus crops was evaluated. Residues of aspar agus roots decompose extremely slowly. At two locations, each with fields where asparagus production was terminated 1 and 10 years before, biomass of root residues was 4180 and 11060 kg dw ha^?1 after 1 year and 420 and 1140 kg dw ha^?1 after 10 years.Although 10-year-old residues were for the greater part decomposed, crude aqueous extracts inhibited root growth of asparagus seedlings significantly and even more of garden cress. In root observation boxes with field soil mixed with non-sterilized or sterilized asparagus root fragments, growth of secondary roots was inhibited. Non-sterilized strawberry roots did not inhibit root growth, suggesting that effects of organic matter were not involved. In a pot experiment, sterilized asparagus root fragments inhibited root growth when added at a rate of 20 g1^?1, but not a 2 g1^?1 Addition of non-sterilized root fragments strongly inhibited root growth at both levels. This was probably due to simultaneous infection byFusarium oxysporum present in these residues. When an asparagus field is replanted, the amount of root residues left behind in soil after termination of the crop in the previous season is about 2 g dw 1^?1, that corresponds to approx. 11000 kg dw ha^?1. This level is too low for considering direct growth inhibition by autotoxins as a major factor. Their possible indirect effects are briefly discussed.  相似文献   

The energy density of water and ice nucleation     

Wilen L 《Science (New York, N.Y.)》1993,259(5100):1469

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A 2000-year tree ring record of annual temperatures in the sierra nevada mountains     

Scuderi LA 《Science (New York, N.Y.)》1993,259(5100):1433-1436

Tree ring data have been used to reconstruct the mean late-season (June through January) temperature at a timberline site in the Sierra Nevada, California, for each of the past 2000 years. Long-term trends in the temperature reconstruction are indicative of a 125-year periodicity that may be linked to solar activity as reflected in radiocarbon and auroral records. The results indicate that both the warm intervals during the Medieval Warm Epoch ( approximately A.D. 800 to 1200) and the cold intervals during the Little Ice Age ( approximately A.D. 1200 to 1900) are closely associated with the 125-year period. Significant changes in the phase of the 125-year temperature variation occur at the onset and termination of the most recent radiocarbon triplet and may indicate chaotic solar behavior.  相似文献   

Mesostructure silicate names     

Stucky G 《Science (New York, N.Y.)》1993,262(5134):640

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Converting weapons to fuel     

Prussin SG  Glassey CR  Melese G 《Science (New York, N.Y.)》1993,260(5108):607

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The biological history of a seaway     

Vermeij GJ 《Science (New York, N.Y.)》1993,260(5114):1603-1604

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E-mail withdrawal prompts spasm     

Taubes G 《Science (New York, N.Y.)》1993,262(5131):173-174

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