Cultural Values in Intergroup and Single-Group Social Dilemmas.

Do cultural values influence the manner in which people cooperate with one another? This study assessed cultural characteristics of individuals and then related these characteristics to cooperative behavior in social dilemmas. Participants were assessed for their degree of vertical and horizontal individualism and collectivism, cultural values identified by Triandis (1995). They made choices in either a single-group or an intergroup social dilemma.

Electrophysiological evidence for direction-specific rotary evoked potentials in human subjects--a topographical study.

The spatio-temporal characteristics of rotary evoked potentials are unknown up to now. Transient motions with sinusoidal velocity profile (60 degrees , 47.12 degrees /s, 74.

Perception of direction of visual motion. II. Influence of linear body acceleration.

We investigated whether linear whole-body acceleration along the interaural y-axis influenced the concurrent perception of visual motion direction as has been shown for angular accelerations. A sled running on air bearings along a 7.5-m track was used to accelerate 18 subjects at two different linear accelerations.

Perception of direction of visual motion. I. Influence of angular body acceleration and tilt.

We investigated, psychophysically, the influence of body rotation on visual motion direction thresholds for both upright sitting and tilted observers. Four angular accelerations (0, 20, 40 and 60 degrees/s2) were combined with 3 concurrent backward-tilt positions (0, 45 and 90 degrees). This led to combined stimulation of the semicircular canals and otoliths.

Position and velocity responses from the otoliths and the canals: results from ESA's parabolic flights.

Background: Transient (i.e., phasic) bell-shaped vestibularly evoked potentials (VESTEP's) were recorded from the human scalp during whole body rotation about the vertical z-axis using a multi-axis rotary chair (yaw-motion).

Studies on the long-term stabilities of the background of radionuclides in inductively coupled plasma mass spectrometry (ICP-MS)A review of radionuclide determination by ICP-M.

The long-term stabilities of the ICP-MS background of nine radionuclides are studied, of which the signals are partially superimposed by polyatomic interferences or affected from carry-over and memory effects. The background generated by the ICP flame, by two pure waters, and by nitric acid (2% v/v) was investigated in detail. A minimum of 50 measurement points was used for each long-term investigation.

Uptake and distribution of the boron-containing ether lipid B-Et-11-OMe in tumor-bearing mice.

Ether lipids in general are accumulated in tumor tissue with a favorable tumor/healthy tissue ratio. The uptake of the boron-containing analog rac-1-(9-o-carboranyl)nonyl-2-methyl-glycero-3-phosphocholine (B-Et-11-OMe) was studied in C3H mice bearing the murine mammary carcinoma AT17 and in BALB/c mice bearing an osteosarcoma. Boron concentrations of tumor, blood, liver and kidney were followed up to 48 h by inductively coupled plasma emission spectrometry and inductively coupled plasma mass spectrometry.

Processing of visual motion direction in the fronto-parallel plane in the stationary or moving observer.

To examine the effect of concurrent self-motion on the perception of the direction of object-motion, random-dot kinematograms were employed in which the strength of the directional signal was manipulated by varying the percentage of coherently moving pixels. The subject's task was to indicate the motion direction of briefly presented displays while undergoing whole body rotations with angular accelerations of 0, 5, 15, or 45 degrees/s2. The perception of the direction of visual motion in the horizontal plane was impaired only when visual and vestibular motion directions were incongruous.

Vestibularly evoked potentials (VESTEPs) of the horizontal semicircular canals under different body positions in space.

We recorded vestibularly evoked potentials (VESTEPs) using natural vestibular stimuli simulating the form of a normal head movement ("raised cosine"). Its smooth course was designed to minimize all possible sources of artifacts of mechanical, electrical, and physiological origin. This motion profile was applied to subjects (Ss) sitting upright, thus stimulating the horizontal semicircular canals alone, as well as when they were tilted in different positions in steps of 30 degrees about the interaural y-axis, which had the effect of modulating the otolithic contribution to the horizontal VESTEP.

MARDER--multi-axes rotation device for experimental research. A new concept for investigations of the vestibular, oculomotor, and visual systems of humans in three-dimensional space.

A hydraulically driven, digitally servo-controlled multi-axes rotary chair is described. This device generates motion profiles with the subjects head in the center of rotation mainly in order to adequately stimulate the semicircular canals which are sensitive sensors for angular accelerations. This newly developed apparatus allows for motion stimuli which are below the vestibular threshold up to accelerations of 12 rad/s2 (688 degrees/s2) and is thus suitable for a variety of experiments in the field of vestibular, oculomotor, and intersensory research in 3-dimensional space.

Identification of the visual motion area (area V5) in the human brain by dipole source analysis.

The retinal periphery of nine healthy subjects was stimulated with computer-generated random-dot kinematograms. These stimuli provided almost isolated visual motion information and minimal position cues. Pattern-reversal stimuli at the same location in the visual field were used for control.

Impairment of auditory processing by simultaneous vestibular stimulation: psychophysical and electrophysiological data.

The aim of the experiments reported here was to demonstrate auditory-vestibular interaction both on a psychophysical and on an electrophysiological basis in humans. These results correspond to those recently obtained during simultaneous visual and vestibular stimulation and illustrate experimentally the importance of auditory information processing in spatial orientation. Time to detect the motion of a sound source is significantly increased when simultaneous vestibular stimulation is induced by passive sinusoidal head oscillations.

Electrophysiological evidence for visual-vestibular interaction in man.

The aim of the experiments reported here was to confirm electrophysiologically the results of psychophysical experiments, which demonstrated that thresholds for object-motion detection are significantly raised during both concurrent active or passive sinusoidal head oscillations and during visually induced self-motion perception (circularvection, CV). This intersensory inhibition could now be demonstrated electrophysiologically by recording visual motion evoked potentials both during concurrent sinusoidal head oscillations and during visually induced apparent self-motion of the objectively stationary subject. Recordings of visual contrast reversal evoked potentials failed to reveal such an interaction.

Active immunization against gonadotropin-releasing hormone combined with androgen supplementation is a promising antifertility vaccine for males.

Male rats and rabbits were immunized against gonadotropin-releasing hormone (GnRH) conjugated to tetanus toxoid (GnRH10-TT) using only materials approved for humans. Testosterone (T)-releasing implants or the long-lasting T ester testosterone-17-trans-4-n-butyl-cyclohexane carboxylate (TE) was used as supplemental androgen for maintaining libido. Immunization against GnRH10-TT effectively suppressed fertility (spermatogenesis) in rats and rabbits.

Influence of head or trunk oscillations on visually induced self-motion perception in humans.

The influence of concurrent head or trunk movements on optokinetically induced self-motion perception has been investigated by measuring circularvection (CV) latencies. Active head as well as passive trunk oscillation cause an increase in circularvection latency of about 50% as compared to latencies with the head and trunk stationary during full field optokinetic stimulation. The results point towards an intersensory inhibition of self-motion perception.

Object-motion detection affected by concurrent self-motion perception: applied aspects for vehicle guidance.

Thresholds and response times for object-motion detection are significantly raised during concurrent real or visually induced self-motion perception. This was demonstrated by standardized laboratory experiments in which subjects had to react to a suprathreshold visual stimulus (1 degree-light spot moving with 5 degrees/s speed) under different stimulus conditions of simultaneously perceived self-motion. Elevated response times (mean elevation factor: 3.

Importance of the visual cortex for postural stabilization: inferences from pigeon and frog data.

Optokinetically induced self-motion with its consequences for postural balance is based upon visual-vestibular convergence. It is a matter for speculation which visual pathways--subcortical accessory optic tract and/or cortical striate projection--convey optokinetic information to the central vestibular system. The functional significance of the visual cortex was tested by a behavioral approach in two animals, selected for their different evolutionary stage: frog (midbrain visual center); pigeon (primitive neocortical center).

Object-motion detection affected by concurrent self-motion perception: psychophysics of a new phenomenon.

Thresholds for object-motion detection are significantly raised when concurrent self-motion perception is induced by either vestibular, or visual, or cervico-somatosensory stimulation. Active sinusoidal horizontal head oscillations with compensatory vestibulo-ocular reflex (VOR) and foveal or eccentrical target presentation; 'passive' head movements with fixation suppression of the VOR; pure body oscillations with the head fixed in space (cervical stimulation); optokinetically induced apparent self-motion (circularvection). This new visual phenomenon of a physiological 'inhibitory interaction' between object- and self-motion perception seems to have a somatosensory motor analogue.

European vestibular experiments on the Spacelab-1 mission: 5. Contribution of the otoliths to the vertical vestibulo-ocular reflex.

The gain of the vestibulo-ocular reflex in the sagittal plane may be due to a cooperation between otoliths and the vertical semi-circular canals. The present space experiment was aimed at studying the influence of the absence of gravity stimulation on the otoliths, by comparing VOR gain and phase in space and on ground. Measurements were taken the 5th and the 7th day of flight, the subject being asked to perform, eyes closed, active head oscillations in pitch while fixating an imaginary target in front of him.

European vestibular experiments on the Spacelab-1 mission: 2. Experimental equipment and methods.

A series of vestibular experiments were performed in conjunction with the first Spacelab mission, consisting of sets of pre-, in- and postflight tests. A multipurpose experimental apparatus used for the diverse flight and ground tests is presented. Additional apparatus together with the multi-purpose package were used in the baseline data collection facility at the landing site at NASA Dryden Flight Research Facility for the ground tests.

Differential effects of ambivalent visual-vestibular-somatosensory stimulation on the perception of self-motion.

The direction of perceived self-motion was determined as a function of combined visual-vestibular and vestibulo-somatosensory stimulations about the earth's vertical z-axis by means of a rotary chair and drum system. The predominant influence of concurrent antagonistic vestibular stimulation on circular vection (CV) even at small accelerations has been demonstrated by several studies in the past. The results of the present paper do not confirm the generally assumed influence of the vestibular system on exocentric motion perception, but instead produce evidence of the dominance of the visual channel even at high acceleration levels.

Interaction between perceived self-motion and object-motion impairs vehicle guidance.

When one is riding in a vehicle, perceptual thresholds for motion of objects are significantly elevated above those determined under corresponding but simulated conditions in the laboratory without concurrent self-motion perception. Authorities on road traffic accidents should thus consider an additional perceptual time of at least 300 milliseconds for detecting critical changes in headway beyond the usual reaction time. Detection times thus corrected consequently lead to an alteration of our conception of safe intervehicle distances in a convoy.

Effects of rectilinear acceleration and optokinetic and caloric stimulations in space.

During the flight of Spacelab 1 the crew performed a number of experiments to explore changes in vestibular function and visual-vestibular interactions on exposure to microgravity. Measurements were made on the threshold for detection of linear oscillation, vestibulo-ocular reflexes elicited by angular and linear movements, oculomotor and posture responses to optokinetic stimulations, and responses to caloric stimulation. Tests were also conducted on the ground, during the 4 months before and on days 1 to 6 after flight.

The European vestibular experiments in Spacelab-1.

A series of experiments were performed in the Spacelab-1 mission on November/December, 1983, pre-, in-, and postflight. These experiments covered various aspects of the functions of the vestibular system, the inflight tests comprising threshold measurements for linear movements in three orthogonal axes, optokinetic stimulation, vestibulo-ocular reflexes under linear and angular accelerations, caloric stimulation with and without linear accelerations; pre- and postflight tests repeated the inflight protocol with the addition of subjective vertical and eye counter-rotation measurements using a tilt table. One of the most surprising and significant results was the caloric test: strong caloric nystagmus on the two subjects tested was recorded inflight; this was contrary to what was expected from Barany's convection hypothesis for caloric nystagmus.

[Visual prevention from motion sickness in cars].

The differential effects of vision on motion sickness in cars were tested under real road conditions using linear accelerations, in order to confirm earlier laboratory results on visual modulation of vestibular nausea induced by angular accelerations of the body. The 18 voluntary subjects were exposed to repetitive braking maneuvers (linear accelerations: 0.1-1.