Changes In Lateral Position Research Articles

Project PRIME: road markings for motorcycle casualty reduction (an overview of findings from 2020 to 2022)

Pioneering road markings for motorcyclists, designed as Perceptual Rider Information for Maximising Expertise and Enjoyment (PRIMEs) were installed on approach to demanding bends at 22 trial sites and two comparison sites across the West Highlands of Scotland. The markings provided a series of ‘gateways’ to encourage safer riding. With 32,213 motorcyclists observed, the following statistically significant results were observed: speed reductions at 10 trial sites; positive changes in lateral position at the final PRIME gateway marking at 15 trial sites and positive changes in lateral position at the apex of the bend at 13 trial sites; reductions in braking at nine trial sites; increases use of PRIME road markings across 18 of the 22 trial sites. No statistically significant effects were observed at the comparison sites. These findings are discussed in relation to the ‘Road Safety Framework to 2030’ and the ‘Safe System’ approach to reducing motorcycle casualties.

Stereo Vision Controlled Variable Rate Sprayer for Specialty Crops: Part II. Sprayer Development and Performance Evaluation

Highlights A real time stereo vision controlled variable rate sprayer for specialty crops was developed. The stereo vision system of the sprayer detected outdoor trees with similar canopy profiles under travel speeds ranging from 3.2 to 8 km h-1. Canopy volume measurements of the sprayer were impacted by lateral distances between the sprayer and the tree center and travel speeds. The sprayer required less than 200 ms from tree canopy detection to spray decisions. The sprayer achieved spray volume reductions from 72.6% to 80.5% compared to constant rate spray application. Abstract. A real time variable rate sprayer controlled by a stereo vision system was developed to increase the accuracy of spray applications and reduce the use of crop protection products. The sprayer was designed to detect tree canopies and calculate its volume using depth images from the stereo vision system, and discharge corresponding spray volumes every 200 ms through the embedded software in the graphical user interface. The sprayer was evaluated in an apple orchard at different travel speeds (3.2 to 8.0 km h-1) for its performance in detecting canopy and measuring its volume. In addition, spray volume, deposition, and coverage of the variable rate application of the sprayer were evaluated against a constant rate application. Test results showed that the sprayer detected visually similar tree canopies during the evaluations, although its canopy volume measurements deviated from manually measured canopy volume from 0.11 to 0.83 m3 due to lateral position changes of the sprayer. The sprayer adjusted duty cycles of pulse width modulated valves to accurately spray the intended volume for detected canopies (0.073 to 0.083 L m-3) and only used spray volumes of 19.5% to 26.7% compared to a constant rate spray application (338 L ha-1). The constant rate spray application generally had more spray deposition and coverage in tree canopies than the variable rate sprayer, as expected since its spray volume was approximately 3.7 times higher. However, the mean spray depositions from the constant rate spray application were significantly varied (p=0.05) by tree sizes, while the variable rate spray application achieved statistically equivalent mean spray depositions regardless of tree sizes. The stereo vision controlled sprayer offers a cost-effective real-time variable rate spray option for growers with the potential to perform other tasks by using image processing algorithms while applying crop protection products. Keywords: Automation, Canopy volume, Crop protection, Depth image, Orchard, Precision agriculture, Real-time application.

Safer road users: Investigating the influence of PRIME road markings on motorcycle rider behaviour

Innovative road markings for motorcyclists, designed as Perceptual Rider Information for Maximising Expertise and Enjoyment (PRIMEs) were installed on the approach to demanding left-hand bends at six trial sites and a comparison site across the West Highlands of Scotland. These road markings were presented as a series of ‘gateways’ to encourage safer riding. Video data were collected to measure motorcycle speed, lateral position, braking and use of the road markings, before and after the PRIMEs were installed. A total of 9,594 motorcyclists were observed. Across the six trial sites, statistically significant reductions in speed were observed (at three sites). Significant changes in lateral position were observed at the final PRIME gateway marking (at one site), and at the apex of the bend (at three sites). Reduced braking was observed at three sites and there was a statistically significant increase in the use of PRIME road markings across four of the sites. No statistically significant effects were observed at the comparison site. These findings are discussed in relation to sustained effects and aspects of the ‘Safe System’ approach that are relevant to reducing motorcycle casualties.

Safeguarding motorcyclists: Trialing new PRIME road markings for casualty reduction

Dedicated road markings for motorcyclists were installed on the approach to demanding bends at 10 sites across the West Highlands of Scotland. These road markings were designed as Perceptual Rider Information for Maximising Expertise and Enjoyment (PRIMEs) which presented a series of ‘gateway’ markings to encourage safer riding. Video data were collected to measure motorcycle speed, position, braking and use of the road markings, before and after the PRIMEs were installed. A total of 12,949 motorcyclists were observed. Speed reductions were observed across four of the 10 sites, changes in lateral position at the final PRIME gateway marking and apex of the bend were observed across all 10 sites and seven sites respectively; reduced braking was observed at two sites and there was an increase in the use of PRIME road markings across eight of the 10 sites. These findings are discussed in relation to the ‘Safe System’ approach to improving motorcycle safety.

Temporal binding of auditory spatial information across dynamic binaural events

Simultaneity judgments were used to measure temporal binding windows (TBW) for brief binaural events (changes in interaural time and/or level differences [ITD and ILD]) and test the hypothesis that ITD and ILD contribute to perception via separate sensory dimensions subject to binding via slow (100+ ms)—presumably cortical—mechanisms as in multisensory TBW. Stimuli were continuous low-frequency noises that included two brief shifts of either type (ITD or ILD), both of which are heard as lateral position changes. TBW for judgments within a single cue dimension were narrower for ITD (mean = 444 ms) than ILD (807 ms). TBW for judgments across cue dimensions (i.e., one ITD shift and one ILD shift) were similar to within-cue ILD (778 ms). The results contradict the original hypothesis, in that cross-cue comparisons were no slower than within-cue ILD comparisons. Rather, the wide TBW values—consistent with previous estimates of multisensory TBW—suggest slow integrative processing for both types of judgments. Narrower TBW for ITD than ILD judgments suggests important cue-specific differences in the neural mechanisms or the perceptual correlates of integration across binaural-cue dimensions.

Effects of positioning upon the vertical dimension on cone beam computed tomography

Aims: The present study was performed to investigate the effects of different positioning modalities on vertical dimensional measurements of potential implant sites in cone beam computed tomography (CBCT) images. Methods: Twenty-eight implant shaped stainless steel pins were placed in every tooth location in a dry skull and CBCT images of these pins were obtained with the skull in different positions in lateral and forward-backward planes. The following angles were used in both planes: –10°, –5°, 0°, +5° and +10°. The CBCT images were obtained with the Kodak 9000 CBCT imaging system (Carestream Health Inc, Rochester NY, USA). Panoramic slice views were used for measurement allowing all pins to be viewed on the same slice. The measurements of vertical dimensions of the pins were performed twice on the obtained images by the same observer according to tooth regions and the data was statistically analyzed. Results: Statistical analysis revealed that for forward-backward movements measurement differences were statistically significant in maxillary anterior, mandibular anterior and mandibular premolar regions and for lateral position changes statistically significant differences were observed in the maxillary premolar and maxillary molar regions for imaging modalities changing between the angles of –10° and +10°. Conclusion: Changing the skull position reduces the accuracy of vertical dimensions on CBCT scans. The results of the present study showed that skull movements between –10o and +10o effects the anterior regions significantly, but for other regions of the jaws the measurements are within a clinically acceptable range.

Lapses of attention as outcome measure of the on-the-road driving test

Lapses are brief periods of inattention and reduced alertness which may be a risk factor for car crashes. The Dutch on-the-road driving test is applied to examine effects of CNS drugs on driving, using the standard deviation of lateral position (SDLP) as primary outcome measure. This paper examines the utility of an alternative outcome measure, lapses, to determine the degree to which CNS drugs impair driving. Data from two double-blind, placebo-controlled on-the-road driving studies that examined the residual effects of hypnotic drugs were reanalyzed. The treatments were zaleplon and zolpidem tested 4h after middle-of-the-night administration, and ramelteon and zopiclone tested 8.5h after bedtime administration. In addition to SDLP, outcome measures related to lapses (number, total duration, and maximum deviation) were computed. A lapse was defined as a continuous change in lateral position of greater than 100cm, lasting for at least 4s. Both SDLP and lapses were able to detect significant driving impairment after middle-of-the-night administration of zolpidem (10 and 20mg) and bedtime administration of ramelteon (8mg) and zopiclone (7.5mg) relative to placebo. Both measures found no differences from placebo after middle-of-the-night administration of zaleplon (10 and 20mg). The number of lapses was more sensitive in differentiating treatment from placebo than the maximum deviation of a lapse or their duration. After considering different lapse duration criteria, a lapse was redefined as a continuous change in lateral position of greater than 100cm, lasting for at least 8s. This change in definition did not significantly alter the outcome of the statistical analyses. In addition to SDLP, the number of lapses is a useful outcome measure to identify treatments that impair driving. Future research should determine the unique contributions of SDLP and lapses in defining the potential risk of CNS drugs on driving.

Timing of C-Arm Drape Contamination

Surgical site infection remains a concern in orthopedic surgery, and contamination of C-arm covers is a potentially modifiable risk factor. A single-cohort study was conducted using 30 consecutive patients undergoing operative fracture fixation. Cultures were obtained from the C-arm cover after initial draping and every 20 min thereafter. The total number of persons in the operating room (person-hours/h of study time) and the number of door openings were recorded. The C-arm position changes and the time to contamination were monitored. The median time from the start of the operation to contamination was 20 min. There was a 17% contamination rate on initial draping, 50% at 20 min, 57% at 40 min, and 80% by 80 min. The C-arms in five cases were not contaminated during the surgery. Time to contamination correlated significantly with lateral position changes (correlation [r]=0.64; p=0.003) but was not related to C-arm position changes (r=0.22; p=0.34), number of door openings (r=0.20; p=0.39), or person-hours/h (r=0.04; p=0.85). Contamination of the C-arm drape occurs often and early during surgery for orthopedic fractures. We recommend minimal contact with the C-arm to avoid contamination of the surgical field.

Implementation of two tests for measuring sensitivity to temporal fine structure

Objective: To implement two methods for measuring sensitivity to temporal fine structure (TFS) for use in assessing effects of hearing loss and age that may not be apparent from the audiogram. Design: The TFS1 test was described by Moore and Sek (2009). The task is to discriminate a harmonic complex tone from a tone in which all frequency components are shifted upwards by the same amount in Hz. The TFSLF test was described by Hopkins and Moore (2010a). The task is to detect changes in lateral position of a binaurally presented tone based on interaural phase difference (IPD). Both tests have been implemented in software that can be run on a PC with a good-quality sound card. The software includes a routine for measuring the absolute threshold at the test frequency. Results: For each test, an experimental run at a single frequency takes about three minutes. Practice tasks (frequency discrimination of pure tones for TFS1 and discrimination of changes in lateral position based on interaural level difference for TFSLF) are also implemented that are similar to the main task, but easier. Conclusions: The software implementation allows sensitivity to TFS to be measured quickly without a requirement for specialized equipment.

Sound localization by interaural time differences at high frequencies

It is possible for human listeners to lateralize high-frequency noise on the basis of interaural time differences in the fine structure of the envelope. However, the ability to do so makes great demands on the interaural coherence of the noise. This paper explores listeners’ ability to lateralize a broadband, high-passed, coherent-noise signal in the presence of a broadband incoherent masker. Results showed that as the high-pass cutoff frequency increased through the critical region from 1 to 4 kHz, the required interaural coherence increased rapidly, especially for the smaller changes in lateral position. The observed functional behavior can be successfully predicted by a neural model of lateralization based on the centroids of bandwise cross-correlation functions of model peripheral inputs that have been rectified and low-pass filtered [e.g., Bernstein and Trahiotis, J. Acoust. Soc. Am. 100, 1754–1763 (1996)]. The results have implications for the localization of broadband sounds in rooms, where the interaural coherence tends to increase with increasing frequency, but often not rapidly enough to allow the envelope timing information to contribute usefully. [Work supported by NIDCD.]

Extents of laterality and binaural interference effects

Extents of laterality produced by ongoing interaural time delays (ITDs) within high-frequency sinusoidally amplitude-modulated (SAM) target tones were measured in the presence or absence of a second, spectrally remote, diotic, SAM tone. The spectrally remote SAM tones had recently been shown to reduce sensitivity to ITDs conveyed by a 4-kHz SAM tone in a previous experiment employing the same listeners [L. M. Heller and C. Trahiotis, J. Acoust. Soc. Am. 97, 1808-1816 (1995)]. All SAM tones were 100% modulated at 250 Hz and were presented at 77 dB SPL for a duration of 250 ms. The SAM target tone was centered at 4 kHz and the lower-frequency SAM tones were centered at either 500 Hz, 1 kHz, or 2 kHz. The data indicate that spectrally remote, diotic, SAM tones "pull" the lateral position of a 4-kHz SAM tone toward the midline, even when the 4-kHz SAM tone contains an ITD of up to 400 or 600 microseconds. This means that effects of spectrally remote information are not confined to tasks which require that listeners detect, or discriminate between, threshold amounts of ITD. Analyses revealed that changes in lateral position, as measured by an acoustic pointing task, cannot in and of themselves account for the interference effects found in discrimination tasks with similar stimuli. It was found, however, that Buell and Hafter's [J. Acoust. Soc. Am. 90, 1894-1990 (1991)] weighted-combination model, when augmented to include measures of laterality as well as measures of discriminability, could provide reasonably accurate predictions of the amounts of interference obtained in the discrimination task.

The long-lived fusogenic state induced in erythrocyte ghosts by electric pulses is not laterally mobile

The long-lived fusogenic state induced in spherical-shaped erythrocyte ghosts by electric field pulses (Sowers, A.E. 1984. J. Cell Biol. 99:1989-1996; Sowers, A.E. 1986. J. Cell Biol. 102:1358-1362) was studied in terms of how the fusion yield depended on both (a) the location where membrane-membrane contact took place with respect to the orientation of the electric pulse and (b) the time interval between the pulse treatment and membrane-membrane contact. Fusion yields were greater for membrane-membrane contact locations closer to where the pulse-induced transmembrane voltage was expected to be greatest and showed a time interval-dependent accelerating decay. The portion of the membrane that became fusogenic included the area up to a latitude of approximately 38 degrees of arc towards the equators of the membranes. A time interval-dependent increase or decrease in rate of decay in the fusion yield for membrane-membrane contacts induced closer to the equator of the membranes did not occur showing that the pulse-induced fusogenic state is immobile in the early 5-45-s interval after induction and has a rate of decay, which does not permit long time interval changes in lateral position to be measured.

Lateral-position-based models of interaural discrimination.

This letter investigates the hypothesis that lateral position is the only cue available for interaural discrimination experiments using 500-Hz stimuli. The discussion of this hypothesis is in the context of comparisons of the experimental data to predictions of the "position-variable" model of binaural interaction. The model predicts the mean and variance of the subjective lateral position of stimuli used in the discrimination experiments, assuming that discrimination performance is based on optimal processing of this subjective position. To the extent that the laterality predictions of the model are accurate, data that are inconsistent with its predictions would also be problematical for any model based on the subjective laterality of a single binaural image. The predictions (at least qualitatively) describe much of the observed experimental data, including a number of results that have not been addressed by any previous theory. Nevertheless, the observed performance is significantly better than the corresponding predictions for three types of experiments in which the utility of the position cue has been eliminated by experimental design. We believe that our results indicate that changes in lateral position are the primary cue in most interaural discrimination experiments, but that secondary attributes of the perceptual images can be useful when performance based on position alone would be poor.

Visual control during straight road driving

In a laboratory experiment, visual thresholds were determined for change in heading angle and change in lateral position during simulated straight road driving. These thresholds differ for different delineations, forward speeds and exposure durations. The thresholds as found are low enough to be compatible with the precision with which a driver actually keeps course on a straight road. Therefore, they are likely candidates as visual cues for course control by a driver. Some implications for future research are discussed.

A new mechanical method to influence pulmonary perfusion in critically ill patients.

A new device, the Roto-Rest bed, has been used in critically ill patients to effect lateral to lateral position changes and continuous rotation to influence distribution of pulmonary blood flow. Selection of extreme lateral position can be made particularly in cases of respiratory failure with primarily unilateral involvement. Dependent positioning of the uninvolved lung to match ventilation and perfusion can be accomplished simply. Rapid resolution of a large pulmonary contusion serves to illustrate the clinical use of the apparatus.

Comparison among four psychophysical procedures used in lateralization

Psychometrie functions were obtained from two listeners in four psychophysical tasks. The tasks were lateralization procedures in which Os were asked to make discriminations of interaural temporal differences of a 250-Hz tone. The four tasks were: a single-interval yes-no task, a single-interval left-right task, a two-alternative forced-choice task, and a two-interval same-different task. The theory of signal detection provides predictions relating the performances obtained in these four procedures. These predictions could not be verified in this experiment when it was assumed that the Os were listening to changes in lateral position produced by the interaural temporal difference. The data were, however, consistent with the assumption that Os use lateral motion as a cue for detection in two-interval tasks and lateral position as a cue in single-interval tasks.

Gaze-Contingent Adaptation to Prismatic Spectacles

Ivo Kohler reported remarkable after-effects resulting from the prolonged wearing of prismatic spectacles; when the spectacles were removed the apparent size and shape of objects varied with direction of view.' How does a constant retinal image come to evoke different impressions of size and shape? The result obviously is connected with the distortion produced by prisms. A prism displaces light as a function of the angle of incidence and the thickness of glass traversed. Thus, a person wearing wedge-prisms mounted in spectacle-frames (with bases oriented in the same direction) notes a variety of deformations, both when the head is moved while fixating a target, and when the eyes are moved with the head stationary. In general, the after-effects reported by Kohler are the same distortions as those produced by prisms, but in the opposite direction. Kohler's observations of these gaze-contingent after-effects were based upon two Ss, himself and Dr. T. Erisman. Pilot studies by the present authors indicate that Ss exposed to prismatic distortion for as short as 20 days experience such after-effects but that their measurement is difficult. The purpose of the present study was to develop appropriate techniques for verifying the existence of no after-effects and for quantifying them.2 Problem. The present report focuses on the measurement of adaptation to two deformations produced by prisms. The first distortion is contingent upon change in vertical position of the eyes in the head. Specifically, horizontal lines above and below eye-level appear to converge towards the apex of the prism. This distortion is alternatively manifest in the apparent 'shearing' or tilting of a fixated horizontal target as the head is nodded up and down. The second distortion is contingent upon change in lateral position of eyes in the head. Specifically, identical targets viewed through the base and apex of the prism have different apparent widths (the base-