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Biomedical subjects

C K Allen

Publications and source records attributed to C K Allen.

12 recordsLinked to original sources
PubMed2002

Beam-halo measurements in high-current proton beams.

We present results from an experimental study of the beam halo in a high-current 6.7-MeV proton beam propagating through a 52-quadrupole periodic-focusing channel. The gradients of the first four quadrupoles were independently adjusted to match or mismatch the injected beam. Emittances and beamwidths were obtained from measured profiles for comparisons with maximum emittance-growth predictions of a free-energy model and maximum halo-amplitude predictions of a particle-core model. The experimental results support both models and the present theoretical picture of halo formation.

Journal Article↗
PubMed1995

Short-term memory for color names using Stroop material.

A modified Stroop arrangement consisting of color names printed in ink of a different color was used in a release from the proactive inhibition (PI) paradigm. In Exp. 1, half of the subjects were informed prior to a trial whether they were to recall the colors or the color names while the remaining half were not informed in advance. After three trials, half of the subjects were shifted to recalling the other material while control subjects continued with the same recall material. Analysis indicated that (1) when subjects were informed in advance, PI release was found in a color name to color shift, but no PI release was found with a shift from color to color name, and (2) when subjects were not informed in advance, no PI release was observed in either shift condition. Exp. 2 replicated the not-informed condition and introduced a longer stimulus-exposure duration for 160 undergraduates. Except for higher recall scores, the same results were obtained. The results were interpreted in terms of differences in the kinds of encoding operations performed on colors and color names.

Adult↗
PubMed1990

Encoding of colors in short-term memory.

A theory is proposed to explain results from prior experiments on release from proactive inhibition and the recall of colors or color names in short-term memory. It is assumed that colors are encoded in two ways, verbally and perceptually, while color names are encoded only verbally. Assuming that the release occurs when a new and different encoding is performed on changed material, it follows that release from proactive inhibition should occur with shifts from color names to colors but not with shifts in the opposite direction. These results were obtained in prior experiments. In the present experiment ambiguous colors were used to minimize the verbal encoding. As predicted, release from proactive inhibition was found with shifts from ambiguous colors to names as well as with shifts from names to the ambiguous colors.

Adult↗
PubMed1987

Activity: occupational therapy's treatment method. 1987 Eleanor Clarke Slagle lecture.

A philosophical framework to explain the value of using activity as a treatment method is the challenge pursued for this lectureship. Primary resources came from Soviet psychology, the only social science discipline using the concept of activity as a focus of study. The focus of study selected for occupational therapy is disability, which is explained within the context of doing an activity. The patient's purpose for doing an activity is described by the degree of sensorimotor thought processed during a functional state. A hierarchy of activity analysis is used to begin the development of typologies for feasible operations, satisfactory results, and desirable activities. The philosophical framework is applied to three types of patient populations that pose problems in stating treatment objectives, patients that have (a) a good prognosis but one that is associated with alternative explanations for change, (b) a poor prognosis associated with a lifelong disability, and (c) a grave prognosis associated with a progressive loss of functional abilities. A refined treatment hypothesis is suggested: Therapeutic activity compensates for disability by using remaining capabilities to accomplish desirable activities with satisfactory results.

Accident Prevention↗
PubMed1987

Cognitive disabilities: measuring the social consequences of mental disorders.

The disabilities associated with psychiatric illnesses can be separated into six cognitive levels that can be identified by functions the patient is able to perform, by the types of assistance required to compensate for dysfunctions, and by the social dysfunction observed in home and work environments. These cognitive levels can be used to measure the severity of mental disorders; changes in these levels reflect temporal changes in severity that are consequent to treatment and/or natural history of the condition. These cognitive levels can also be used to assess need for hospitalization and/or community placement, readiness for discharge from hospital, and effectiveness of treatment. A collaborative relationship between occupational therapists and psychiatrists is needed for the most effective use of these reliable and objective assessments of cognitive function levels in patients with psychiatric illness.

Activities of Daily Living↗
PubMed1984

Short-term memory for colors and color names in the absence of vocalization.

In a previous experiment, Allen found no release from proactive inhibition using the Brown-Peterson procedure in a group who were shifted from recalling colors to recalling the names of colors. The lack of release suggests that colors and color names are encoded in similar ways. It was argued that the similarity of encoding might have been caused by the procedure of requiring the subjects to say out loud the names of the colors at the time of stimulus presentation and recall. In the present experiment, a procedure was devised that eliminated the need for verbalization of the colors. The same pattern of results was obtained, namely, release from proactive inhibition in the group shifted from recalling color names to colors but not in the group shifted in the opposite direction. It was concluded that if subjects encode colors as a verbal label, then this encoding strategy is not caused by the procedure of requiring the subjects to verbalize the colors.

Color Perception↗