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801.
Rats treated acutely with i.p. fenfluramine showed a profound inhibition of emptying of a chow meal from the stomach. This inhibition was attenuated by previous chronic treatment with fenfluramine. Tolerance to the gastric slowing occured with as few as 2–4 prior injections, a time course which closely matches tolerance to the anorectic effects of the drug. Cerebroventricular injections of fenfluramine and norfenfluramine in anorectic doses also inhibited gastric emptying. 相似文献
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Dzieweczynski Teresa L.; Earley Ryan L.; Green Tracie M.; Rowland William J. 《Behavioral ecology》2005,16(6):1025-1030
Investigations of communication networks in animals have focusedprimarily on determining whether animals extract informationfrom peripheral contests (eavesdropping) or respond to the presenceof bystanders (audience effect). The possibility that an animal'sresponse to being watched might be context dependent, however,has been explored in far less detail. This study investigatedthe influence of two contexts, exposure to audiences of differentsexes and presence or absence of a nest, on the aggressive behaviorof interacting male Siamese fighting fish, Betta splendens.Males interacted in the presence (male, female) or absence ofan audience in three different nest conditions (0, 1, or 2 nests).Audience sex and territorial status influenced aggressive behaviorin the interacting males, but a strong audience x nest interactionalso was uncovered. Males were more aggressive when neithermale had a nest and a male audience was present than when afemale or no audience was present. Males also were more aggressivewhen only one male had a nest and a male audience was presentthan when a female or no audience was present. When both maleshad nests and a male audience was present, however, males wereless aggressive than when only one male or neither male hada nest. In sum, aggressive behavior was influenced by the interactionbetween audience and nest; neither nest nor audience alone wassufficient to explain the results. Male Siamese fighting fishalter their behavior based on both external cues, the sex ofthe audience, and internal cues, reproductive state and resourcepossession. Our results emphasize the importance of consideringaspects of an animal's environment when examining audience effectsand communication networks in general. 相似文献
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Heterogeneity in the number of potentially infectious contacts and connectivity correlations (“like attaches to like” i.e.,
assortatively mixed or “opposites attract” i.e., disassortatively mixed) have important implications for the value of the
basic reproduction ratio R
0 and final epidemic size. In this paper, we present a contact-network-based derivation of a simple differential equation model
that accounts for preferential mixing based on the number of contacts. We show that results based on this model are in good
qualitative agreement with results obtained from preferential mixing models used in the context of sexually transmitted diseases
(STDs). This simple model can accommodate any mixing pattern ranging from completely disassortative to completely assortative
and allows the derivation of a series of analytical results. 相似文献
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