The crane's foot: The rise of the pedigree in human genetics

The standard pedigree used by geneticists is intimately connected to the history of genetics. Pedigrees drawn today are based on standards established in the early decades of the twentieth century. Those standards were established by geneticists who pursued an active interest in eugenics. The slightly different standards followed in America vs. England to some extent followed the stronger support of Mendelism by the Americans, as well as the individual preferences of the leading human geneticists in those countries.     

Development of knowledge bases and the reliability of a decision support system for behavioral treatment consultation for persons with mental retardation: The Mental Retardation-Expert

The development of expert and decision support systems requires the collection, organization, codification, and storage of a body of specialized knowledge. The development, using reconstructive methods, of two such knowledge bases, the first containing the current scientific literature and the second containing an expert’s knowledge, is described for an automated decision support system, the Mental Retardation-Expert. This system provides practitioners with assistance in the treatment of aggressive, self-injurious, and destructive behaviors displayed by individuals with mental retardation or developmental disabilities. The average interobserver reliability of the expert knowledge base ranged from 92.5% to 95.0% when calculated across four clinicians’ assessments of 31 abstracted cases.     

An examination of concept lattices,types, and functions inRoget’s International Thesaurus

The notions of objects and attributes are essential to knowledge representation. Rudolf Wille’s concept lattices group objects and attributes into concepts, with concepts organized in a lattice, so that some concepts are subconcepts of others. This paper applies certain aspects of type theory to concept lattices in order better to facilitate the representation of knowledge inRoget’s International Thesaurus. Of particular interest is a formal analysis of functions providing concept lattices with a way of representing procedures and actions that currently are not present in the thesaurus.     

A collection of 4,741 word fragments that have unique completions with respect to 146,205 words

A collection of 4,741 word fragments that have a unique completion is described. All word fragments are specified by two letters (e.g.,__Q__U__can only be completed by the word LIQUEURS). The words completing these fragments range in length from five to nine letters. The fragments are unique with respect to a pool of 146,205 words, which helps rule out the possibility that obscure words could be used as a completion to the fragments. The collection of fragments as well as the words that complete them is available in ASCII format on computer disks or in printed form.     

Psychophysiological and behavioral differences as a function of age and Parkinson’s disease

Differences related to age and to specific neurological (Parkinsonian) damage were studied by contrasting, respectively, old (mean age 64 years) and young (27 years) subjects (N=15), and old-normal (N=15) and old-Parkinsonian (N=15) subjects. Both behavioral as well as psychophysiological dependent variables were employed. The behavioral measure was performance on a discrimination learning task, while the psychophysiological measures were based on habituation to a repeated tone stimulus and on a Pavlovian differential conditioning preparation. The behavioral task showed predominantly age-related differences, with the young learning faster. Another age-related difference was interpreted as showing a more insight-like learning process in the young. Response-bias (beta) values did not differ between groups. Age-related differences also emerged more clearly than specific-neurological-damage differences in the psychophysiological data. The older subjects manifested markedly less autonomic conditioning, which was probably due to a lowering of reactivity, as well as the emergence of habituation to the (loud-noise) unconditional stimulus. A correlational analysis of discrimination conditioning also yielded age-related differences. Most notably, reactivity played a greater role in conditioning in the old than in the young subjects. The results illustrated how psychophysiological measures can provide information that complements those provided by behavioral measures.     

Effects of spatial filtering and lack of effects of visual imagery on pattern-contingent color aftereffects

Checkerboards contain fundamental two-dimensional Fourier components oriented 45° from the edges of individual checks. Previous studies have shown that contingent color aftereffects following adaptation to chromatic checkerboard stimuli were associated with the fundamental components rather than the edges, In the present experiments, we measured contingent color aftereffects, using the method of constant stimuli, after subjects adapted to unfiltered checkerboards and checkerboards with the fundamental Fourier components removed. The adaptation stimuli were magenta (or green) squares and green (or magenta) diamonds; the test stimuli were vertical or oblique sine-wave gratings with different saturations, After adaptation to unfiltered checkerboards, aftereffects contingent on the fundamental components were obtained. In contrast, after adaptation to filtered stimuli, aftereffects of smaller magnitude were found to be aligned with the edges. The data support the previous findings of spatial-frequency-contingent color after-effects with checkerboard adaptation stimuli and indicate that the aftereffects can be associated with edges if the fundamental components of adaptation stimuli are removed by spatial filtering. We reexamined the possibility of color aftereffects induced by imagery of checkerboards. Contrary to the previous reports, no significant aftereffects were obtained.     

Asymmetries in the regulation of visually guided aiming

An experiment was conducted to examine the contribution of sensory information to asymmetries in manual aiming. Movements were performed in four vision conditions. In the full-vision condition (FV), subjects were afforded vision of both the hand and the target throughout the course of the movement. In the ambient-illumination-off condition (AO), the room lights were extinguished at movement initiation, preventing vision of the moving limb. In the target-off (TO) condition, the target was extinguished upon initiation of the movement. In a no-vision (NV) condition, ambient illumination was removed and the target was extinguished upon initiation of the response movement. Results indicated that accuracy was superior in the full-vision and target-off conditions and when movements were made by the right hand. Movements made by the right hand were also of shorter mean duration. The magnitudes of performance asymmetries were uninfluenced by vision condition. Analyses of movement kinematics revealed that movements made in conditions in which there was vision of the limb exhibited a greater number of discrete modifications of the movement trajectory. On an individual-trial basis, no relationship existed between accuracy and the occurrence of discrete modifications. These data suggest that although vision greatly enhances accuracy, discrete modifications subserved by vision reflect the imposition of nonfunctional zero-order control processes upon continuous higher-order control regimes.     

A Computational Model of the Simplest Motor Program

A computational procedure (program) is defined to generate control signals for the motoneuron pools of agonist and antagonist muscles that will move a limb segment from one stationary position to another. The program accounts for the ability to move different distances with different inertial loads and for the influence of instructions concerning movement speed and accuracy. These motor commands allow the program to produce EMG patterns as well as force and kinematic trajectories that are consistent with much of the data found in the literature of these movements. The program is premised on the notion that kinematically defined tasks are accomplished by programming commands to the motoneuron pools, based on only a few cognitively recognized kinematic and dynamic features of the task. Most of the features found in EMG and kinematic patterns can be considered consequences of the program's algorithmic procedures rather than specifically planned features of those movements.