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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2008.10.012 Byline: Javier delBarco-Trillo, M. Elsbeth McPhee, Robert E. Johnston Abstract: In laboratory studies, hamsters (Mesocricetus spp.) show intense male-male aggression, thus making them an excellent model system for studies of the functional and mechanistic bases of aggression. In a field study of golden hamsters, M. auratus, in the wild, however, the few documented male-male interactions were not highly aggressive. Thus, we tested the hypothesis that familiarity modulates aggression in hamsters. Previous investigations of the effects of familiarity on aggression have mostly involved familiarization of unfamiliar individuals through agonistic interactions. Here we allowed male Turkish hamsters, M. brandti, to become familiar with each other by housing them together but separated by a wire-mesh partition (thus 'nonagonistic' familiarity). We found that although nonagonistic familiarity did not decrease investigation of the familiar male, it did decrease the occurrence of fights, the number of fights and the percentage of time fighting; it also increased the latency to fight. These results are consistent with the 'dear enemy' hypothesis, which proposes that males are less aggressive towards familiar neighbours than they are towards unfamiliar conspecifics because previous interactions provide enough information about the other individual to render severe aggression unnecessary. Most importantly, our results suggest that information gained about other individuals through nonagonistic interactions decreases the frequency and intensity of fights with those individuals. We conclude that results from laboratory studies on aggression that do not consider the kind of social interactions that individuals have in nature should be interpreted with caution. Author Affiliation: Department of Psychology, Cornell UniversityU.S.A. Article History: Received 22 April 2008; Revised 9 August 2008; Accepted 9 October 2008 Article Note: (miscellaneous) MS. number: A08-00256

In humans, individuals recognize other individuals by numerous types of independent information, such as the quality of the voice, appearance of the face, smell, gait, and posture. Humans also have integrated memories of others--that is, in response to a face or a voice the individual is recognized by name and other information about that individual is remembered. In many nonhuman species, individual recognition also occurs. Although observational studies suggest that individuals of some nonhuman species may be able to use several different cues for individual recognition, little experimental proof for this is available. Golden hamsters have at least 5 individually distinctive odors and they develop integrated, multiodor memories (concepts) of familiar individuals, as shown by across-odor habituation experiments. Little is known, however, about the conditions that are necessary to develop such integrated memories. In these experiments we investigated what kinds of experiences were necessary for male hamsters to develop multiodor memories of females. The results show that exposure to all of the odors of another individual was not sufficient to develop such multiodor memories but that physical contact between the subjects and stimulus animals was necessary. Multiodor representations were developed after interactions with anesthetized individuals, confirming the finding that physical contact was important but also showing that interaction with an awake, behaving individual was not necessary to form multiodor representations of other individuals. We are not aware of experimental proof for integrated, multicomponant memories in any other nonhuman species. Keywords: individual recognition, hamster, odors, memory, animal cognition

Severe acute respiratory syndrome's (SARS) causative virus has been isolated, and Yang and colleagues have recently reported the efficacy of a prototype vaccine in a mouse model of infection. Other laboratories are currently testing viral-vector system as a means of delivering selected SARS-CoV genes for vaccination.

The new model does not require pre-specification of cutting patterns and it resolves the non-linearity in the one-dimensional cutting stock problem. It explicitly includes practical constraints such as sequence related constraints, minimum run length constraints and pattern cardinality constraints.