INTRODUCTION The aim of this study was to compare centering ability and dentin removal of three rotary systems in curved root canals of extracted teeth. MATERIALS AND METHODS Sixty root canals of mandibular first molars with curvatures ranging between 25-35(o) were divided into three groups of 20 teeth each. Based on pre-instrumentation radiographs that assessed the angle and the radius of ca...

A formal proof is pnnided that Anderson's {1990) rational model of categorization generalizes the Medin and Schaffer {1978) context model. According to the context model, people represent categ<>ries by storing individual exemplars in memoiy. According to the rational mode!, people represent categories in terms of midtiple exemplarclusters or prototypes. In both models, a multiplicative rule is...

ION PROCESSES DURING CONCEPT LEARNING: A STRUCTURAL VIEW Janice Skorstad Dedre Gentner Doug Medin Computer Science Department Psychology Department Psychology Department University of Illinois University of Illinois University of Illinois

Does the similarity between two items change over time? Previous studies (Goldstone & Medin, 1994; Gentner & Brem, 1999) have found suggestive results but have relied on interpreting complex interaction effects from “deadline” decision tasks in which the decision making process is not well understood (Luce, 1986). Using a self-paced simple decision task in which the similarity between two items...

If people are required to respond very quickly in a samedifferent task, their judgments of sameness are heavily reliant on attribute matches, despite the fact that when given ample time, the judgments seem to rely chiefly on relational matches (Goldstone & Medin, 1994). One interpretation of this temporal pattern is that attribute matches enter into the comparison process before relational matc...

Aortic medial amyloid is the most prevalent amyloid found to date, but remarkably little is known about it. It is characterised by aberrant deposition of a 5.4 kDa protein called medin within the medial layer of large arteries. Here we employ a combined approach of ab initio protein modelling and 13C-direct detection NMR to generate a model for soluble monomeric medin comprising a stable core o...

In the present study, GECLE (Matsuka, 2003) was used as a general modeling framework to systematically compare the plausibility of two prominent assumptions about internal representations of neural network (NN) models of human category learning. In particular, exemplar-model friendly Medin and Schaffer’s 5/4 stimulus set (1978) was used for comparing prototypeand exemplar-based NN models. The r...

Much research (e.g., Keil, 1989; Murphy & Medin, 1985; Rips, 1989) has emphasized the critical role that domain knowledge plays in categorization judgments. Recent instantiations of this view (e.g., Ahn, et al., 2000; Rehder & Hastie, 2001) have focused on characterizing how causal knowledge supports categorization decisions. We suggest that a more satisfactory account of categorization can be ...