Vertical gaze angle: absolute height-in-scene information for the programming of prehension.

One possible source of information regarding the distance of a fixated target is provided by the height of the object within the visual scene. It is accepted that this cue can provide ordinal information, but generally it has been assumed that the nervous system cannot extract "absolute" information from height-in-scene. In order to use height-in-scene, the nervous system would need to be sensitive to ocular position with respect to the head and to head orientation with respect to the shoulders (i.e. vertical gaze angle or VGA). We used a perturbation technique to establish whether the nervous system uses vertical gaze angle as a distance cue. Vertical gaze angle was perturbed using ophthalmic prisms with the base oriented either up or down. In experiment 1, participants were required to carry out an open-loop pointing task whilst wearing: (1) no prisms; (2) a base-up prism; or (3) a base-down prism. In experiment 2, the participants reached to grasp an object under closed-loop viewing conditions whilst wearing: (1) no prisms; (2) a base-up prism; or (3) a base-down prism. Experiment 1 and 2 provided clear evidence that the human nervous system uses vertical gaze angle as a distance cue. It was found that the weighting attached to VGA decreased with increasing target distance. The weighting attached to VGA was also affected by the discrepancy between the height of the target, as specified by all other distance cues, and the height indicated by the initial estimate of the position of the supporting surface. We conclude by considering the use of height-in-scene information in the perception of surface slant and highlight some of the complexities that must be involved in the computation of environmental layout.

Locus of control of smokers, nonsmokers, and nonpracticing smokers.

In this survey, score analyses of 123 male and female respondents, ages 21 to 33 years, yielded no significant differences between either sex and smokers versus nonsmokers on Rotter's locus of control scale. Of particular interest was that nonpracticing smokers (quitters) scored more internal than either smokers or nonsmokers.

Effects of the angiotensin II receptor antagonist losartan on herpes simplex virus-type 2 infection of cultured vero and cardiac neonatal myocytes.

Previous studies indicate that captopril, an angiotensin II converting enzyme inhibitor, attenuates cardiomyopathy in a murine viral myocarditis model. Accordingly, we investigated the ability of captopril as well as angiotensin II (AII) and losartan, a nonpeptide AII receptor antagonist, to alter infection or replication of herpes simplex virus- type 2 (HSV-2) in cultured cardiac and vero cells. Neither captopril nor AII influenced the ability of HSV-2 to replicate in either cell type. Losartan, however, caused a dose dependent decrease in pfu ability on vero cells with an ED50 of 1.35 mM. In cultured myocytes, losartan (400 microM) reduced significantly %LDH released (54.9 +/- 7.5 vs 29.1 +/- 4.2 in infected controls) and % pfu released (40.9 +/- 8.4 vs 14.8 +/- 3.8 in infected controls) into the media. These results suggest that losartan attenuates deleterious effects of the virus by preventing release of the virus by the cells.

Locus of control and law knowledge: a comparison of normal, retarded and learning disabled adolescents.

Individualization of instruction of mentally handicapped adolescents may be facilitated by understanding of relevant variables associated with the learning skills required for coping with community life. This study explores the relationship between knowledge of such skills and locus of control (belief concerning the relative contribution of chance or others to outcomes and events which follow one's behavior). Comparisons of scores of 94 high school students on the Bialer-Cromwell Locus of Control Scale and a test of knowledge of law about such matters as credit, theft, and marriage, indicated that: (1) High school students in standard and college preparatory programs were more likely to see outcomes as determined by their own behaviors than were retarded and learning disabled students; (2) High school students in standard and college preparatory programs were better informed about legal matters crucial to community life than were mentally retarded and learning disabled students; (3) Mentally retarded and learning disabled students did not differ in law knowledge or on locus of control; (4) Locus of control was not directly related to IQ within the retarded-learning disabled group; (5) A moderate positive correlation was found between locus of control and law knowledge for the total group. Findings support Rotter's social learning theory. These findings also suggest that educators may need to provide more direct and specific training in critical aspects of layman's law for most retarded and learning disabled adolescents, as well as for average students who manifest external locus of control beliefs.