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Biomedical subjects

W B Thompson

Publications and source records attributed to W B Thompson.

14 recordsLinked to original sources
PubMed1998

Metamemory accuracy: effects of feedback and the stability of individual differences.

This study addressed two questions about metamemory accuracy: how feedback about recall performance affects confidence-recall accuracy and whether individual differences in confidence-recall accuracy are stable across different sets of test items. College students answered general knowledge questions and made confidence ratings about the correctness of the answers. Half the students were told whether their answers were correct. All students answered half the questions a second time. The results show that feedback did not produce a general improvement in metamemory accuracy; the improvement was specific to the questions for which feedback was provided. Also, individual students' metamemory accuracy showed moderate alternate-forms stability when each test was made up of 250 items. Therefore, researchers studying individual differences in metamemory accuracy on recall tasks should use tests that yield several hundred responses.

Adult↗
PubMed1996

Instability of individual differences in the association between confidence judgments and memory performance.

There are large individual differences in the degree of association between the accuracy of memories and subjective confidence in those memories. Are these differences stable within the same test, and between alternate forms of a test? In Experiment 1, college students were tested on 3 recognition memory tasks, then retested 2 weeks later on alternate forms of the same tasks. The relationship between confidence judgments and recognition performance displayed low split-half stability and low alternate-forms stability. A second experiment with elderly adults replicated these findings. In a third experiment, college students recalled answers to general knowledge questions and rated confidence in the correctness of each answer. Individual differences in the association between confidence and recall performance were not stable across the odd- and even-numbered items on the test. These data indicate the need for the development of procedures that will produce stable estimates of individuals' metacognitive accuracy.

Adult↗
PubMed1995

Design and synthesis of piperidine-3-carboxamides as human platelet aggregation inhibitors.

A detailed structure-activity analysis was carried out using eight 1-alkyl(aralkyl)nipecotamides (type 5), 33 bis-nipecotamidoalkanes and aralkanes (type 6), and 7 N,N'-bis(nipecotoyl)-piperazines (type 7) as inhibitors of human platelet aggregation. Steric factors played an important role in determining the activity of type 5 compounds possessing an an appropriate degree of hydrophobic character. Types 6 and 7 compounds were more potent than the corresponding type 5 molecules. Hydrophobic character appeared to influence the activity of type 6 compounds. A 3-substituent on the piperidine ring was necessary for antiplatelet activity; the substituent should be preferably an amide with its C attached directly to the ring. 3,5-Disubstitution and 2-substitution led to a decline in activity. Optimal activity was attained when the two nipecotoyl ring N atoms were connected by an aralkyl group, and separated by approximately 7 A. It is suggested that van der Waals forces and pi interactions may govern the inhibitor-platelet interaction. The most potent type 6 inhibitor was alpha,alpha'-bis[3-(N-ethyl-N-butylcarbamoyl)piperidino]-p-xylene (6i). The most potent type 5 compound was 1-decyl-3-(N,N-diethylcarbamoyl)piperidine (5a). Any substitution on the piperazine ring of type 7 compounds led to a decline in activity, the most active analog being N,N'-bis(1-decylnipecotoyl)piperazine (7a). It is suggested that nipecotamides interact with anionic platelet sites located 7 A from each other and connected by a hydrophobic well.

Adult↗
PubMed1989

Structure-from-motion by tracking occlusion boundaries.

Active visual tracking of points on occlusion boundaries can simplify certain computations involved in determining scene structure and dynamics based on visual motion. Tracking is particularly effective at surface boundaries where large, discontinuous changes in depth are occurring. Two such techniques are described here. The first provides a measure of ordinal depth by distinguishing between occluding and occluded surfaces at a surface boundary. The second can be used to determine the direction of observer motion through a scene.

Algorithms↗
PubMed1987

Postoperative radiation of open head and neck wounds.

Complication rates are lower using postoperative radiation therapy and cure rates at least compatible to preoperative radiation therapy. However, one of the concerns with postoperative radiation treatment is the possibility of delay in beginning the treatment because of an unhealed surgical wound. A delay of more than 6 weeks is detrimental. In order to study the effect of radiation therapy on incompletely healed wounds, a retrospective chart review of such cases during the period 1977 to 1984 was undertaken. One hundred and eighty-five patients had planned postoperative radiation therapy, and 13 of these began radiation therapy with an unhealed wound or fistula. Six of 10 wounds closed spontaneously, 4 required surgical closure, and 3 failed to heal. Seven patients in this study died with cancer, 2 died of other causes, 3 are alive without disease, and 1 patient remains alive with disease. We conclude that giving radiation therapy to an open wound with appropriate precaution can be done without serious complications.

Adult↗
PubMed1984

Face memory and hemispheric preference: emotionality and extraversion.

Subjects made arousing or nonarousing judgments about photographs of strangers, then had an unannounced recognition test over the photographs. Emotional orienting tasks led to better retention than nonemotional tasks. Assuming emotionality is predominantly a right-hemisphere activity, then this result is consistent with other research showing a right-hemisphere advantage in processing faces. This difference was most clear for subjects with a right-hemisphere cognitive style. Extraversion had no effect on face recognition, nor did a subject's cognitive style seem to be associated with extraversion or neuroticism scores.

Adult↗
PubMed1982

Distribution of histidine-rich basic protein, a possible keratin matrix protein, in rat oral epithelium.

The indirect fluorescent-antibody technique was used to locate histidine-rich basic protein, filaggrin. In the newborn, immunofluorescence was seen in the cornified layers and in keratohyalin granules throughout the mouth using antibody specific for epidermal filaggrin, a distribution similar to that in epidermis where it is thought that filaggrin functions as the keratin matrix protein. In the adult immunofluorescence was in keratohyalin granules of palate, buccal and tongue epithelium but in the stratum corneum was limited to the soft palate with weak, patchy areas in the densely keratinized epithelium of the hard palate and tongue. Immunofluorescence was delineated at the boundary between the soft and hard palates. A protein apparently identical to epidermal filaggrin was identified in extracts of newborn palate by its mobility on sodium dodecyl sulphate-polyacrylamide gels and subsequent reaction with the antibody used for immunofluorescent studies. This protein was not detected in extracts of adult oral epithelia. Both newborn and adult tissues contained high mol. wt cross-reactive protein, suggestive of the filaggrin-precursor protein extractable from keratohyalin granules. The distribution of filaggrin was consistent with its function as a keratin matrix protein in the newborn oral epithelium and some less densely keratinized regions of the adult. However, in the adult mouth, filaggrin is not detectable in the stratum corneum of the most densely keratinized regions. Thus, the protein must be lost or its antigenic sites altered with maturation of the animal, depending on the type and extent of keratinization.

Aging↗
PubMedDate not supplied

Automated computer screening of chest radiographs for pneumoconiosis.

The results of two complementary approaches for performing diagnostic screening for the presence of coal workers' pneumoconiosis (CWP) from the routine posterior-anterior chest radiograph are presented. The first is a digital approach utilizing the measurement of image texture, while the second uses hybrid optical-digital methods involving the optical Fourier transform. Both approaches yield classification results comparable to experienced radiologists.

Coal Mining↗