Least Generalizations and Greatest Specializations of Sets of Clauses

The main operations in Inductive Logic Programming (ILP) are generalization and specialization, which only make sense in a generality order. In ILP, the three most important generality orders are subsumption, implication and implication relative to background knowledge. The two languages used most often are languages of clauses and languages of only Horn clauses. This gives a total of six different ordered languages. In this paper, we give a systematic treatment of the existence or non-existence of least generalizations and greatest specializations of finite sets of clauses in each of these six ordered sets. We survey results already obtained by others and also contribute some answers of our own. Our main new results are, firstly, the existence of a computable least generalization under implication of every finite set of clauses containing at least one non-tautologous function-free clause (among other, not necessarily function-free clauses). Secondly, we show that such a least generalization need not exist under relative implication, not even if both the set that is to be generalized and the background knowledge are function-free. Thirdly, we give a complete discussion of existence and non-existence of greatest specializations in each of the six ordered languages.Comment: See http://www.jair.org/ for any accompanying file

Geophysical Research

Contains reports on two research projects.National Aeronautics and Space Administration (Grant NGR-22-009-131)National Aeronautics and Space Administration (Grant NGR-22-009-114)National Aeronautics and Space Administration (Contract NAS 12-436

Linkages Among Preschoolers\u27 Playground Behavior, Outcome Expectations, and Parental Disciplinary Strategies

To explore relationships among parent\u27s self-reported disciplinary strategies, preschoolers\u27 outcome expectations, and playground behavior, 136 mothers of preschool-age children (age range = 39-71 months) participated in home disciplinary style interviews. Measures of preschoolers\u27 outcome expectations and observations of childrens\u27 prosocial, antisocial/disruptive, and nonsocial/with-drawn playground behavior in preschool settings were also obtained. Results indicated that power-assertive mothers had preschoolers who engaged in more antisocial/disruptive behavior and who expected successful instrumental outcomes for hostile methods of resolving peer conflict. Preschoolers with such outcome expectations also participated in more antisocial playground behavior. Older preschoolers of inductive mothers engaged in more prosocial behavior and expected prosocial behavior to lead to both instrumental gains and enhanced relations with peers. Preschoolers who were more prosocial envisioned friendly-assertive strategies as leading to instrumental gains and, in the case of less nonsocial behavior, to enhanced relations with peers. Children\u27s outcome expectations were also found to be different for older versus younger preschoolers. Evidence was also obtained suggesting that maternal discipline and outcome expectations make separate and independent contributions to children\u27s social and aggressive play behavior. © 1992, Taylor & Francis Group, LLC. All rights reserved

Development of Locomotor-Related Movements in Early Infancy

This mini-review focuses on the emergence of locomotor-related movements in early infancy. In particular, we consider multiples precursor behaviors of locomotion as a manifestation of the development of the neuronal networks and their link in the establishment of precocious locomotor skills. Despite the large variability of motor behavior observed in human babies, as in animals, afferent information is already processed to shape the behavior to specific situations and environments. Specifically, we argue that the closed-loop interaction between the neural output and the physical dynamics of the mechanical system should be considered to explore the complexity and flexibility of pattern generation in human and animal neonates

Differential activation of lumbar and sacral motor pools during walking at different speeds and slopes

Organization of spinal motor output has become of interest for investigating differential activation of lumbar and sacral motor pools during locomotor tasks. Motor pools are associated with functional grouping of motoneurons of the lower limb muscles. Here we examined how the spatiotemporal organization of lumbar and sacral motor pool activity during walking is orchestrated with slope of terrain and speed of progression. Ten subjects walked on an instrumented treadmill at different slopes and imposed speeds. Kinetics, kinematics, and electromyography of 16 lower limb muscles were recorded. The spinal locomotor output was assessed by decomposing the coordinated muscle activation profiles into a small set of common factors and by mapping them onto the rostrocaudal location of the motoneuron pools. Our results show that lumbar and sacral motor pool activity depend on slope and speed. Compared with level walking, sacral motor pools decrease their activity at negative slopes and increase at positive slopes, whereas lumbar motor pools increase their engagement when both positive and negative slope increase. These findings are consistent with a differential involvement of the lumbar and the sacral motor pools in relation to changes in positive and negative center of body mass mechanical power production due to slope and speed.NEW & NOTEWORTHY In this study, the spatiotemporal maps of motoneuron activity in the spinal cord were assessed during walking at different slopes and speeds. We found differential involvement of lumbar and sacral motor pools in relation to changes in positive and negative center of body mass power production due to slope and speed. The results are consistent with recent findings about the specialization of neuronal networks located at different segments of the spinal cord for performing specific locomotor tasks

Developmental appropriateness of kindergarten programs and academic outcomes in first grade

This study explored the relationship between the developmental appropriateness of kindergarten classroom instruction and first-grade report card grade overall averages and averages in reading, language, spelling, math, science, and social studies. The interactive roles that gender, SES, and kindergarten classroom type play in children’s later achievement were also examined. The sample consisted of166first-grade children who hadattended kindergarten classrooms with teaching practices identified as predominately developmentally appropriate or developmentally inappropriate. Findings indicated that firstgraders from more appropriate kindergarten classrooms had higher reading averages than children from less appropriate kindergarten classrooms. Females had higher overall and subject area averages than males. Significant interaction effects indicated that high SES children from less appropriate kindergarten classrooms hadhigheroverall averages and higher averages in all subjects except reading, when compared with low SES children from less appropriate classrooms. Low SES children from more appropriate kindergarten classrooms had higher overall averages and higher averages in all subjects except reading when comparedwith low SES children from less appropriate kindergarten classrooms. No significant differences were found between high and low SES children from more appropriate kindergarten classrooms. © 1993 Taylor & Francis Group, LLC

Universal behavior of multiplicity differences in quark-hadron phase transition

The scaling behavior of factorial moments of the differences in multiplicities between well separated bins in heavy-ion collisions is proposed as a probe of quark-hadron phase transition. The method takes into account some of the physical features of nuclear collisions that cause some difficulty in the application of the usual method. It is shown in the Ginzburg-Landau theory that a numerical value $\gamma$ of the scaling exponent can be determined independent of the parameters in the problem. The universality of $\gamma$ characterizes quark-hadron phase transition, and can be tested directly by appropriately analyzed data.Comment: 15 pages, including 4 figures (in epsf file), Latex, submitted to Phys. Rev.

Congenital tumors and nonimmune hydrops fetalis

Peer Reviewe