An application of a Theorem of Ash to finite covers

The technique of covers is now well established in semigroup theory. The idea is, given a semigroup S, to find a semigroup having a better understood structure than that of S, and an onto morphism of a specific kind from to S. With the right conditions on , the behaviour of S is closely linked to that of . If S is finite one aims to choose a finite . The celebrated results for inverse semigroups of McAlister in the 1970s form the flagship of this theory.Weakly left quasi-ample semigroups form a quasivariety (of algebras of type(2, 1)), properly containing the classes of groups, and of inverse, left ample, and weakly left ample semigroups. We show how the existence of finite proper covers for semigroups in this quasivariety is a consequence of Ashs powerful theorem for pointlike sets. Our approach is to obtain a cover of a weakly left quasi-ample semigroup S as a subalgebra of S × G, where G is a group. It follows immediately from the fact that weakly left quasi-ample semigroups form a quasivariety, that is weakly left quasi-ample. We can then specialise our covering results to the quasivarieties of weakly left ample, and left ample semigroups. The latter have natural representations as (2, 1)-subalgebras of partial (one-one) transformations, where the unary operation takes a transformation to the identity map in the domain of . In the final part of this paper we consider representations of weakly left quasi-ample semigroups.This work was supported by the London Mathematical Society, Fundação para a Ciência e a Tecnologia, Centro de Álgebra da Universidade de Lisboa, Centro de Matemática da Universidade do Porto and projects POCTI/32440/MAT/2000 and POCTI/32817/Mat/2000 of FEDER.Special issue of Studia Logica: Algebraic Theory of Quasivarieties Presented by M. E. Adams, K. V. Adaricheva, W. Dziobiak, and A. V. Kravchenko     

Encoding fluency is a cue used for judgments about learning

The authors used paired-associate learning to investigate the hypothesis that the speed of generating an interactive image (encoding fluency) influenced 2 metacognitive judgments: judgments of learning (JOLs) and quality of encoding ratings (QUEs). Results from Experiments 1 and 2 indicated that latency of a keypress indicating successful image formation was negatively related to both JOLs and QUEs even though latency was unrelated to recall. Experiment 3 demonstrated that when concrete and abstract items were mixed in a single list, latency was related to concreteness, judgments, and recall. However, item concreteness and fluency influenced judgments independently of one another. These outcomes suggest an important role of encoding fluency in the formation of metacognitive judgments about learning and future recall.     

Integrating consultation and program evaluation in school psychology

Consultation approaches to providing psychological services are widely used by school psychologists. Recently, the need for school psychologists to be proficient in educational program evaluation has been recognized. The present paper discusses how school psychologists can use their existing consultation skills as an approach to program evaluation. The integration of consultation skills with evaluation results in an approach to program evaluation that is particularly useful where program goals and objectives are broad and nonspecific (as in many educational innovations). Also, the consultation approach to evaluation is easier for school psychologists to blend with their other roles in schools than the assessment-oriented evaluator role of some evaluation models. The consultation approach to evaluation is illustrated using a federally sponsored training program for school teachers and administrators.     

Structure and Individuality in Psychoanalytic Training: The Israeli Controversial Discussions

The American Journal of Psychoanalysis -     

Event-related brain potentials and subjective probability in a learning task

In a paired associate learning task, subjects responded to each presentation of a nonsense syllable by typing both a three-letter associate and a rating of their confidence that this response was correct or incorrect. Average event-related potentials (ERPs) elicited by the subsequent presentation of the actual paired syllable varied with the interaction of confidence and trial outcome. A larger amplitude P300 was elicited by syllables that informed subjects that they were correct when they thought they were incorrect or that they were incorrect when they thought they were correct than by syllables that confirmed subjects expectations. That this average ERP result was indeed an effect on P300 amplitude, and not an artifact of single-trial variability in P30O latency, was confirmed with a trial-by-trial latency adjustment procedure. Consistent with findings from other tasks, P300 amplitude varied inversely with the subj ective probability of the ERP-eliciting events.     

A “hand-shaking” multiplexer for the IBM 1800

An instrument is described which is used to multiplex the “ready” and “external sync” lines of an IBM 1800’s data channel to 15 external devices. Used with the digital output registers of the computer, the device facilitates the interfacing of non-IBM peripheral devices to the 1800. The multiplexer can be used in any application in which a pair of lines needs to be shared among several devices.