Flash O2 yield experiments are described in spinach chloroplasts and Chlorella after addition of NH4Cl. (1) The damping of the sequence is increased by NH4Cl. (2) The turnover times are accelerated but the reaction during which O2 is released (S3bv leads to S4 leads to S0) is slowed. (3) We ...

The EKG was recorded while Ss differentially responded to auditory or visual stimuli in a reaction time task. The EKG record was analyzed by dividing each R-R interval encompassing a stimulus presentation into 9 equal phases. Reaction times were determined as a function of the phase encompassing stimulus onset while ...

Additional evidence for two separable responses to auxin is presented. The average of 24 control experiments indicated lag times of 12.4 and 35.4 min, and maximum rates of 0.57 and 0.54 mm hr(-1), for the first and second response, respectively. The auxin analog 4-azido-2-chlorophenoxyacetic acid increased the lag time of ...

It has been shown that when man estimates the duration of separate brief time intervals(300-1,000ms), elements of a certain array of time intervals within the same range, the estimation is not affected by changes in the other elements of the array. The complex light and dark intervals are considerably underestimated. ...

A theory is presented of how a driver might visually control his braking. A mathematical analysis of the changing optic array at the driver's eye indicates that the simplest type of visual information, which would be sufficient for controlling braking and would also be likely to be easily picked up ...

The light intensity vs. time curve of the light flash of the living firefly has been measured. Unlike the purified firefly enzyme system in aqueous solution, the living system does not show light decay conforming to a double exponential time curve, to simple first or second order decay, or to ...

Thirteen airline pilots were studied to determine the effect of preceding rotary accelerations on the choice reaction time to the horizontal acceleration of a vertical line on a cathode-ray tube. On each trial, one of three levels of ratary and visual acceleration was presented with the ratary stimulus preceding the ...

Signal summation and minimally adapting tactile stimulation techniques permit the resolution of a critical time domain of the somatosensory evoked response, recorded from human scalp, which is sensitive to the stimulus variables represented by the sensations of tapping and pinprick respectively. The variation of this time-domain suggests the influence of ...

A theoretical proposition that changes in the organization and structure of auditory information result in changes in temporal experience was tested in this study. Changes were measured in the judgment of duration of a 40-second interval that occurred in three different patterns of auditory information among individuals confined to bed. ...

Three human subjects detected unpredictable signals by pressing either of two telegraph keys. The relative frequencies with which detections occurred for the two alternatives were varied. The procedure included a changeover delay and response cost for letting go of a key. All subjects matched the relative time spent holding each ...

The present research joins previous efforts to define more clearly the phenomenon of perceived time as an important social-psychological dimension. In this study, time was considered a socially existential variable that can most meaningfully be measured by comparing two or more subjectively experienced durations, each with the other(s). Combining this ...

The performance of short drop-time a.c. polarography has been examined in detail, and found to be better than that for natural drop-times in almost every respect. Uncompensated resistance terms are smaller and potentiostat stability is improved. In addition, faster potential scanrates and more rapid data acquisition are possible. A variation ...

An achromatic Schmidt design is proposed for use in twin instruments at Kitt Peak and Cerro Tololo (Chile). The use of an achromatic plate, rather than the conventional Schmidt plate, allows extended spectral coverage by virtue of improved aberration correction. The improvement in geometrical blur diameter appears to be on ...

Control of avoidance response patterning by time-correlated stimuli was studied in rhesus monkeys. At several shock-shock = response-shock intervals, the intervals were divided into 8, 4, or 2 time segments by correlating, respectively, 1, 2, or 4 discrete lights of an eight-light display with each successive segment. A further condition ...

Two monkeys (Macaca mulatta) were trained to press a key after onset of a tone and to release it after a 1-sec fixed foreperiod terminated by a light. The effects of imposing temporal contingencies on key release reaction times were determined by reinforcing only those releases whose latencies from the ...

The major problem of measuring candlepower always has been associated with the use of properly corrected phototransducers. Many manufacturers of photodetectors claim to have cells corrected to the equivalent spectral response of the human eye; however, investigations of all these so-called corrected cells revealed that their correction to the ICI ...

The disruptive behavior of a 9-yr-old boy was eliminated by the illumination of a light on the subject's desk, which represented the loss of free time later in the day. Instructions alone failed to reduce the frequency of disruptive behavior. When the light was removed and disruptive behavior no longer ...

Speeds as high as 44 centimeters per second were observed 200 meters above the ocean bottom under the Gulf Stream at 70 degrees W longitude and were associated with time-dependent motion that had a speed range of 40 centimeters per second and a time scale of about 30 days. These ...

Motor-driven, cam-controlled cameras are particularly suitable for simple time-lapse photography. External intervalometers can be arranged to control the duration of each exposure to compensate automatically for widely varying light intensities.

An instrumental technique is described for measuring the variations of transit time of signals through a photodetector as a function of the position of the light beam on the photosurface. Precision of 3 psec may be obtained with simple, commercial components; a coherent light source is not required. Data are ...

1. Post-tetanic potentiation (PTP) was studied at the neuromuscular junction of the frog. The magnitude and time course of PTP was dependent on the number of stimuli in the tetanus, rather than on the frequency or duration of the tetanus. At low temperature the maximum amplitude of PTP was unchanged, ...

1. Experiments were done on Mg-blocked neuromuscular junctions of the frog to study in detail the magnitude and time course of facilitation of the end-plate potential (e.p.p.).2. When two shocks were applied to the motor nerve with an interval of 5 msec or less between them, the amplitude of the ...

Relative sea levels for early post-Pleistocene time are best known from radiocarbon dates of sediments on the continental shelves off Texas and off northeastern United States. Differences in indicated rates of the rise of relative sea level and in depths of the shelf-breaks reveal differential vertical movement of the two ...

In conventional real-time electrooptical signal processors, the variation of the output intensity with time is directly detected with a photodetector. As a result of this, any information carried in the phase of the light is lost. However, if the light is detected coherently, i.e., it is heterodyned with another coherent ...

Reaction times to a dim photopic stimulus were measured on a circle about the fovea, 15 degrees from the line of direct vision. Large variations in reaction time were found on various half meridians and were interpreted as reflecting the distribution of retinal receptors.

In each of two experiments human subjects were intermittently reinforced with money on a fixed-ratio schedule for emitting correct matching responses. A pre-time-out stimulus which signaled removal of positive reinforcement was periodically superimposed. In the first experiment the superimposed pre-time-out stimulus was paired with a 1-min or 4-min response-independent time ...

Because the response and time scales used in plotting cumulative response curves are often poorly selected, ineffective displays often result. The visual cue of a response rate change is the difference, [Formula: see text] between the angles, theta(1) and theta(2), representing the two rates, R(1) and R(2). These variables are ...

Simple reaction times to auditory stimuli varied with the phase of the cardiac cycle in which the stimuli were presented, tending to be fastest to stimuli presented during the P-phase of the electrocardiogram. One hundred reaction times obtained from each of 56 men and women between the ages of 20 ...

1. The reaction time of the direct growth response of the sporangiophore of Phycomyces to light consists of a series of at least three major identifiable components: (a) an exposure period during which photochemical change occurs; (b) a latent period involving products directly consequent upon the photochemical action; and (c) ...

Part I.-An attempt to interpret the available historical and statistical evidence of the distribution, incidence and character of malaria, from the seventeenth century onwards, and to ascertain to what degree the belief is justified that the disease was formerly prevalent and severe, but that within the last fifty years its ...

1. Visual purple solutions are prepared under such conditions that the bleaching reaction is irreversible. 2. A method is described for the colorimetric estimation of very small quantities of visual purple. By this means the kinetics of the bleaching reaction are investigated. 3. The results show that the course of ...