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Biomedical subjects

S C Fischer

Publications and source records attributed to S C Fischer.

9 recordsLinked to original sources
PubMed2000

Robotics and allied technologies in endoscopic surgery.

Endoscopic surgery was developed in the 1970s and 1980s, with initial work conducted by pioneering surgeons. After the development of laparoscopic cholecystectomy, the breakthrough of endoscopic surgery had a great effect on all surgical specialties. Starting with rather simple procedures, such as cholecystectomy, a rapid progression toward more complex procedures, such as reflux or colonic surgery, took place. It was realized at this time that the existing endoscopic instruments allowed only a limited preciseness when performing the procedures, and part of the information from inside the abdominal cavity was not available to the surgeon. This prompted a discussion with engineers concerning the development of more advanced technologies to give those performing endoscopic surgery the same quality of information and manipulation that surgeons have when performing open surgery. These qualities include (1) instruments and manipulators that allow surgical action under endoscopic control with all degrees of freedom; (2) devices that provide surgeons with tactile feedback; and (3) vision systems that provide surgeons with the same quality of visual information as with open surgery, namely, high resolution, excellent color quality, precise spatial information, and a constant clear view for optimal surgical action. At the end of 1999, some of the aforementioned quality concepts found their way into the surgical routine, but most of the concepts are still being developed. Another decade will pass before endoscopic surgery procedures will be closer to the technological goals.

Endoscopy↗
PubMed1993

Perceptual and cognitive factors governing performance in comparative arrival-time judgments.

Four experiments were conducted to investigate factors affecting relative arrival-time judgments in the transverse plane. Across experiments, results indicated an overreliance on relative distance information. The levels of relative velocity and distance used in the arrival-time task were proved discriminable, and performance in both relative velocity and distance judgments predicted performance in the relative arrival-time task. Despite the distance bias, an attempt to integrate relative velocity and distance information was also evidenced. The distance bias appears to have resulted from resource limitations on the concurrent processing of relative velocity and distance information, causing relative velocity information to become resource limited. The final experiment assessed the stability of performance in each of the tasks over time and provided evidence of individual differences in the ability to coordinate information from multiple sources.

Adolescent↗
PubMed1992

Changes in DSM-III-R axis II diagnoses following treatment of obsessive-compulsive disorder.

Seventeen patients with obsessive-compulsive disorder and concomitant personality disorders were treated with pharmacologic and/or behavioral therapy and reassessed after 4 months. Nine of the 10 patients who responded to treatment for obsessive-compulsive disorder no longer met criteria for a personality disorder. Of the seven nonresponders, five continued to meet criteria for a personality disorder.

Adult↗
PubMed1991

Stimulus complexity effects in visual comparisons: the effects of practice and learning context.

This study examined visual comparison performance for 6-24-point random polygon stimuli (Cooper & Podgorny, 1976). Stimulus complexity effects decreased with practice, consistent with Bethell-Fox and Shepard (1988). A difficult discrimination context produced greater complexity effects than an easy discrimination context, consistent with Folk and Luce (1987). The difficult discrimination context also led to more stimulus-specific learning and diminished stimulus complexity effects. Increased stimulus learning resulted in continued skill acquisition, better transfer, and less performance disruption when the task context was equated for all Ss. It is argued that improvements in performance in a perceptual comparison task are not solely a function of the amount of practice provided in responding to particular stimuli. The context in which responses are elicited is equally important and must be accommodated in theories of skill acquisition.

Adolescent↗
PubMed1988

Hemisphere differences for components of mental rotation.

The hemispheric functional lateralization of components of mental rotation performance was investigated. Twenty right-handed males were presented with rotated alphanumerics and unfamiliar characters in the left or right visual field. Subjects decided if the laterally presented stimulus was identical to or a mirror image of a center standard stimulus. Reaction time and errors were measured. Previous mental rotation findings were replicated and the visual field variable produced significant effects for both dependent measures. An overall right visual field advantage was observed in the latency data, suggesting a left hemisphere superiority for at least one component process of the task. A significant interaction in the error data showed that alphanumerics produced less errors in the right visual field than in the left visual field, consistent with a left hemisphere superiority for processing verbal symbolic material. No such hemispheric difference in accuracy was found for unfamiliar characters.

Adult↗
PubMed1977

MSH/ACTH4-10 influences on the CAR in human subjects: a negative finding.

Twenty normal, male, paid volunteers were randomly assigned to MSH/ACTH4-10 or diluent control groups. Following a subcutaneous injection of either 30 mg MSH/ACTH4-10 or diluent, all subjects were placed in an active conditioned avoidance response situation where they learned to avoid a painful electric shock by pressing a key during a safe interval between a warning signal (light) and shock onset. MSH/ACTH4-10 did not influence any parameter of the acquisition or extinction process. The between subjects' variability of autonomic variables was significantly less for the MSH/ACTH4-10 group. Results indicate that inhibition of extinction of conditioned avoidance responding does not generalize across species from rat to man.

Adrenocorticotropic Hormone↗
PubMed1976

Alternative behavioral approaches to the treatment of homosexuality.

Radical changes in attitudes toward homosexuality in American society are integrated into a new perspective for the therapist confronted by a client who engages in homosexual behavior. The traditional mandatory attempt to eradicate homosexual behavior has been expanded into three options, any one of which may be pursued by the therapist at the client's request: (1) modification of homosexual in favor of heterosexual behavior, (2) enhancement of homosexual behavior, and (3) ignoring of homosexual behavior if it is functionally unrelated to the presenting symptoms. Therapists' negative attitudes toward clients who engage in homosexual behavior are such as to abrogate expanded options and may results in therapeutic efforts at modification of homosexual behavior in defiance of the client's expressed wishes. Contrary to current professional belief, careful analysis and the use of appropriate techniques such as systematic desensitization, orgasmic reconditioning, and training in heterosocial skills generally obviate the necessity for aversive procedures in those instances where homosexual behavior is to be modified in favor of heterosexual behavior. Three case histories are presented illustrating the use of each of the expanded options described above.

Attitude↗