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101.
102.
Nicol CJ 《Learning & behavior》2004,32(1):72-81
This review highlights two areas of particular interest in the study of social learning in fowl. First, the role of social
learning in the development of feeding and foraging behavior in young chicks and older birds is described. The role of the
hen as a demonstrator and possible teacher is considered, and the subsequent social influence of brood mates and other companions
on food avoidance and food preference learning is discussed. Second, the way in which work on domestic fowl has contributed
to an understanding of the importance of directed social learning is examined. The well-characterized hierarchical social
organization of small chicken flocks has been used to design studies which demonstrate that the probability of social transmission
is strongly influenced by social relationships between birds. The practical implications of understanding the role of social
learning in the spread of injurious behaviors in this economically important species are briefly considered. 相似文献
103.
In three experiments, rats received pairings of flavor conditioned stimuli with polycose unconditioned stimuli, in either
a simultaneous or a sequential relation. Both temporal relations produced excellent conditioned increases in consumption of
the flavors. Separate presentation of the flavors resulted in extinction in both cases. However, restoring the pairing of
the flavor with polycose resulted in reconditioning only with the sequential, not with the simultaneous, relation. 相似文献
104.
105.
106.
Investigation of the conformational properties of a SAW polymer chain near an impenetrable, non-interacting flat surface showed that the chain at first contracted and orientated itself to slightly parallel when it pulled close to the surface and at last elongated and reoriented itself to slightly perpendicular to the surface at very small distance from the surface. Simulation showed that most of the disappeared configurations were of large size at moderate distance from the surface while they were of small size at very small distance from the surface; and that the mean-square end-to-end distance was much more prone to be influenced by the surface than the mean-square radius of gyration . The orientational correlation between the direction of the longest principal axis of the moment of inertia and end-to-end vector was also discussed. 相似文献
107.
Keith?KoenigEmail author Nan?Davis?Mitchell Thomas?E.?Hannigan J.?Keith?Clutter 《Sports Engineering》2004,7(2):105-117
The speed at which a player can swing a bat is central to the games of baseball and softball, determining, to a large extent,
the hit speed of the ball. Experimental and analytical studies of bat swing speed were conducted with particular emphasis
on the influence of bat moment of inertia on swing speed. Two distinct sets of experiments measured the swing speed of colege
baseball and fast-pitch softball players using weighted rods and modified bats. The swing targets included flexible targets,
balls on a tee and machine pitched balls. Internal mass alterations provided a range of inertial properties. The average measured
speeds, from 22 to 31 m s−1, are consistent with previous studies. Bat speed approximately correlates with the moment of inertia of the bat about a vertical
axis of rotation through the batter's body, the speed generally decreasing as this moment of inertia increases. The analytical
model assumes pure rotation of the batter/bat system about a vertical axis through the batter's body. Aerodynamic drag of
the batter's arms and the bat is included in the model. The independent variable is bat moment of inertia about the rotation
axis. There is reasonable agreement between the model and the measured speeds. Detailed differences between the two suggest
the importance of additional degrees of freedom in determining swing speed. 相似文献
108.
Guido?Candela Paolo?Figini Antonello?E.?ScorcuEmail author 《Journal of Cultural Economics》2004,28(4):285-302
This paper proposes a price index for artists adjusted for the quality of the paintings, based on the ratio between the average market price and the average pre-sale estimate for paintings. We apply this methodology to a group of selected artists and schools presented in auctions worldwide in the period 1990–2001. A comparison with quality unadjusted and hedonic indices is also conducted.JEL Classification: C10, Z11 相似文献
109.
Martin?VeselyEmail author Thomas?Baron Jean-Yves?Le?Meur Tibor?Simko 《Publishing Research Quarterly》2004,20(1):77-83
Conclusion In this paper we briefly described the current status of research in the field of digital libraries interoperability, mainly
with respect to federated data processing such as permitted within the Open Archive Initiative framework. We then presented
the CERN Document Server Software suite that is a free software package main-tained by CERN providing an online digital library
solution for mid- to large-sized document repositories. The set of CDSware modules was described and the differ-ences with
other existing tools briefly mentioned. Finally we have mentioned a typical usage statistics illustrating the scope of grey
literature and networked con-ditions of the CERN Document Server.
We pointed out that the current trend in grey literature management goes toward institutional repositories build upon the
distributed and federated model. Further research is going on within the CDS collaboration in this area, focused particularly
on (i) semantic interoperability using ontologies in distributed and federated data processing and (ii) ranking technologies
when searching grey literature in OAI compliant repositories. 相似文献
110.
Summary What will be the future of ONIX? Some argue that wider industry acceptance will lead to increased efficiencies in the transfer
of book data, which will ultimately benefit book sales. ONIX still has to overcome many challenges: its implementation cost
is high, whole-salers and aggregators are still using different spreadsheets and information sources. Furthermore, MS Excel
as an alternative solution is widely available and accepted by the industry. Small publishers need more education and a straightforward
demonstration of ONIX’s return on investment. An outreaching of the helping hand of professional organizations is strongly
suggested to foster the adoption process among small players. It is the role of the AAP and BISG to get their memberships
to think about what is good for all members as a whole throughout the industry. As an organization BISG can recommend, educate,
and promote the standard. It cannot, however, bring pressure or demand organizations use it. Publishers, retailers, and wholesalers
make those decisions for themselves and quite apparently the majority do not yet see the rewards. Market players need to determine
the cost versus benefit and as long as distributors and retailers agree on receiving other formats, ONIX will never take a
strong hold in the marketplace. After all, publishers should compete against each other with good books and not with multiple
computer codes. 相似文献