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1.
Glycogen of enteric bacteria   总被引:7,自引:7,他引:0       下载免费PDF全文
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Because toothpaste and other menthol/surfactant‐containing products have residual effects, researchers should ensure that enough time has elapsed between use of toothpaste and evaluation of food products. In this study, orange juice, coffee, sausage and processed cheese were profiled under controlled conditions and at 4, 12, 30 and 60 min after panelists brushed with a strongly mentholated toothpaste. Residual effects of the toothpaste at 4 min reduced several aromatic attributes, but did not affect most fundamental taste or texture attributes. A mint aromatic was observed in some food products after toothpaste use, even after 12 min. Chemesthetic attributes were diminished when a product was presented within 12 min of brushing. Results suggested that the amount of time needed between brushing and tasting depended on the food product. Orange juice, an acidic beverage, required at least an hour's delay; fatty, solid foods could be tasted almost immediately after toothbrushing if provided a warm‐up sample first.  相似文献   
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The impact of the crayfish Orconectes virilis on aquatic macrophytes   总被引:1,自引:0,他引:1  
SUMMARY. 1. The impact of crayfish on the biomass, density and shoot morphology of four submersed plant species was examined under semi-natural conditions. Male or female crayfish ( Orconectes virilis ) were held for 5 weeks at biomasses of 0, 5, 10 or 18 g m−2 (live weight) in twelve plastic pools (4.67 m2, surface area) containing Potamogeton richardsonii, Myriophyllum exalbescens, Nuphar variegatum and Sparganium eurycarpum .
2. Crayfish significantly affected biomass, density and/or shoot morphology of all four macrophyte species. Differences in the effect of crayfish on macrophyte growth were related to plant species, crayfish sex and activity, and the abundance of alternative foods.
3. The effect of female crayfish on macrophyte growth was generally stimulatory. Myriophyllum and Potamogeton biomass, Potamogeton density and Myriophyllum length increased in the presence of female crayfish, possibly due to the reduction in herbivorous snails as a result of crayfish predation. In contrast, plant growth decreased in the presence of male crayfish: Myriophyllum, Nuphar and Potamogeton biomass, Myriophyllum and Sparganium density, and Sparganium and Poiamogeton length were reduced at male crayfish biomasses between 5 and 18 g m−2.
4. These results indicate that even relatively low densities of crayfish can greatly affect the growth of submersed aquatic plants. Because of their ability to modify aquatic macrophyte, macroinvertebrate and, ultimately, fish communities, the introduction of crayfish into lakes where they do not occur could have a major effect on the structure and composition of the littoral zone.  相似文献   
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The distribution of the New Zealand flatworm (Artioposthia triangulata) in Scotland was surveyed between July 1991 and February 1993. There were 348 records from domestic gardens, 56 from botanic gardens, garden centres and nurseries, with only 13 from farms. Although most of the records came from around the major cities the flatworm was found to have become established throughout the Scottish mainland and some of the Islands, e.g. Bute, Gigha, Orkney and Skye. The impact of the flatworm on earthworm populations in agricultural land in Scotland was, as yet, found to be minimal but the fact that seven adjacent farms near Dunoon were infected suggested it could be spread from farm to farm and that in the West of Scotland it could become widespread in agricultural land.  相似文献   
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