Control volume analysis related to putt-putt boat     

Jaywant?H.?ArakeriEmail author 《Resonance》2004,9(6):92-95

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Schüleraktivitäten beim selbstorganisierten Lernen und deren Auswirkungen auf den Lernerfolg     

Jürgen?SeifriedEmail author 《Zeitschrift für Erziehungswissenschaft》2004,7(4):569-584

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Wiltrud Gieseke (Hrsg.): Handbuch der Frauenbildung     

Barbara?DrinckEmail author 《Zeitschrift für Erziehungswissenschaft》2004,7(3):454-456

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Development,direction, and damage limitation: Social learning in domestic fowl     

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   

Extinction and retraining of simultaneous and successive flavor conditioning     

Higgins T  Rescorla RA 《Learning & behavior》2004,32(2):213-219

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   

Susanne von Below: Bildungssysteme und soziale Ungleichheit. Das Beispiel der neuen Bundesländer     

Nicolle?PfaffEmail author 《Zeitschrift für Erziehungswissenschaft》2004,7(4):588-590

Ohne Zusammenfassung  相似文献   

The Nature and Development of Scientific Reasoning: A Synthetic View     

Antone?E.?LawsonEmail author 《International Journal of Science and Mathematics Education》2004,2(3):307-338

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Dynamic Monte Carlo simulation of linear SAW polymer chain near a flat surface     

黄建花  韩世钧 《浙江大学学报(A卷英文版)》2004,5(6):699-704

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   

The influence of moment of inertia on baseball/softball bat swing speed   总被引：1，自引：1，他引：0  

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   

Price Indices for Artists – A Proposal     

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