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Late spoilage of cheese is due to gas formation during lactic acid fermentation by spore-forming, gram-positive, anaerobic clostridia of the species Ciostridium tyrobutyricum, Clostridium butyricum and Clostridium sporogenes. Since small numbers of such clostridial spores readily cause considerable losses in cheese production, spore numbers of fewer than 100 spores/liter must be determined reliably. Until recently, the only reliable method available was the time-consuming (7 days) and cumbersome Most Probable Number Method (MPN). The objective of this study was to examine the feasibility of using impedance technology as an alternative method for the enumeration of clostridial spores. Three to fifteen replicates of 7.5–12.0 mL samples were tested using an impedimetric method with and without the addition of Oxyrase to generate anaerobic conditions within the impedance measurement cells. Results were obtained in less than 48 h. Data derived from the rapid impedance method were statistically comparable to those obtained using the reference method (MPN).  相似文献   
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Abstract: Mammalian females change their behavior during the last stages of pregnancy and during the weaning as a response to new energetic requirements and antipredator behavior. From March 2001 to December 2004, we studied the effects of parturition and weaning on home-range sizes and habitat selection in 28 female Alpine ibex (Capra ibex) in a 1,700-ha free area in the Gran Paradiso National Park (Western Italian Alps). We calculated Kernel home range enclosing 95% of each female's locations according to seasonal and bimonthly timescales. Pregnancy did not seem to modify spatial behavior. Lactating females showed smaller home ranges than nonlactating ones after the birth period in June-July. Hot summers slowed kids' growth and prolonged maternal care, modifying mothers' behavior. In summer 2003, which was hotter and drier than usual, weaning females showed even smaller home ranges. Because of their use of antipredator tactics during the weaning season, lactating females showed a higher use of safer habitats, such as rocky slopes. Our results are consistent with the findings of previous cervid and bovid studies, and they suggest that ungulate mothers may move to suboptimal, but safer, habitats during weaning to reduce the predation risk for their offspring.  相似文献   
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A membranous, cap-like structure was discovered in the bryozoan genus Hallopora from upper Ordovician siltstones from Sardinia. The structure is interpreted to be analogous to the perimetrical attachment organ and to the part of the membranous sac sustaining the sphincter muscle in Recent cyclostomes. The progressive mineralization of the cap-like apparatus occurred in later ontogenetic stages of the colony in order to have the function of a terminal diaphragm. This diaphragm is related to a particular degeneration—regeneration cycle very similar to the cyclic growth patterns (intracolony overgrowths) of some post-Palaeozoic cyclostomes. After this phase the colony seems to end its life cycle.  相似文献   
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