Significant Reduction In Speed Research Articles

Abstract P2-11-11: Tissue sound speed: A novel imaging biomarker for measuring tamoxifen response

Abstract PURPOSE. Studies have shown that a decrease in mammographic density (MD) or lowering of background parenchymal enhancement (BPE) on MRI after initiation of tamoxifen therapy predicts a favorable response in the preventive or adjuvant settings. However, performing serial mammograms poses radiation concerns, while serial MRIs carry high cost as well as risk of multiple Gadolinium doses. Previous studies have shown that tissue sound speed, derived from whole breast ultrasound tomography measurements, is a surrogate biomarker of MD. Ultrasound is ideal for performing serial measurements because it is fast and poses almost no risks. The purpose of this study was to evaluate repeated measures of the sound speed biomarker at 3, 6 and 12-months following tamoxifen initiation. METHOD AND MATERIALS. We performed a case-control comparison involving 74 participants referred by a health professional to undergo tamoxifen therapy (cases) and 150 matched participants with no history of breast cancer (controls). The cases were scanned with ultrasound tomography at baseline (i.e. before start of tamoxifen therapy), and then at 3, 6 and 12 months after tamoxifen initiation. Controls were scanned at baseline and 12 months. In the case group, sound speed was measured pre-treatment in the contralateral breast to avoid potential influences of tumor-related changes on density. In the control group, a single randomized breast was scanned. A pairwise t-test was used to assess differences in sound speed over time and between cases and controls. RESULTS. There was a steady decline in sound speed over the 12-month period for women undergoing tamoxifen therapy (mean(SD): -3.0(8.2) m/s; P=0.001). Furthermore, significant sound speed reductions were observed as early as 4-6 months after tamoxifen initiation (mean(SD): -2.1(6.8) m/s; P=0.008). In contrast, the controls demonstrated no significant change in sound speed over a 12-month period, and the difference between case-control groups was statistically significant (P=0.0009). DISCUSSION. Breast sound speed decreases rapidly after tamoxifen initiation while it remains steady for the control group. These results suggest that sound speed may be a biomarker of response to tamoxifen. Further studies are needed to assess whether this observation can predict clinical response. CONCLUSION. Ultrasound tomography may have utility in monitoring breast sound speed change as a potential biomarker of clinical tamoxifen response. Citation Format: Neb Duric, Mark Sak, Mark Sherman, Ruth Pfeiffer, Sharon Fan, Michael Simon, David Gorski, Teri Albrecht, Haythem Ali, Peter Littrup, Rachel Brem, Gretchen Gierach. Tissue sound speed: A novel imaging biomarker for measuring tamoxifen response [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-11-11.

Simultaneous Tracking of Pseudomonas aeruginosa Motility in Liquid and at the Solid-Liquid Interface Reveals Differential Roles for the Flagellar Stators.

Bacteria sense chemicals, surfaces, and other cells and move toward some and away from others. Studying how single bacterial cells in a population move requires sophisticated tracking and imaging techniques. We have established quantitative methodology for label-free imaging and tracking of individual bacterial cells simultaneously within the bulk liquid and at solid-liquid interfaces by utilizing the imaging modes of digital holographic microscopy (DHM) in three dimensions (3D), differential interference contrast (DIC), and total internal reflectance microscopy (TIRM) in two dimensions (2D) combined with analysis protocols employing bespoke software. To exemplify and validate this methodology, we investigated the swimming behavior of a Pseudomonas aeruginosa wild-type strain and isogenic flagellar stator mutants (motAB and motCD) within the bulk liquid and at the surface at the single-cell and population levels. Multiple motile behaviors were observed that could be differentiated by speed and directionality. Both stator mutants swam slower and were unable to adjust to the near-surface environment as effectively as the wild type, highlighting differential roles for the stators in adapting to near-surface environments. A significant reduction in run speed was observed for the P. aeruginosa mot mutants, which decreased further on entering the near-surface environment. These results are consistent with the mot stators playing key roles in responding to the near-surface environment.IMPORTANCE We have established a methodology to enable the movement of individual bacterial cells to be followed within a 3D space without requiring any labeling. Such an approach is important to observe and understand how bacteria interact with surfaces and form biofilm. We investigated the swimming behavior of Pseudomonas aeruginosa, which has two flagellar stators that drive its swimming motion. Mutants that had only either one of the two stators swam slower and were unable to adjust to the near-surface environment as effectively as the wild type. These results are consistent with the mot stators playing key roles in responding to the near-surface environment and could be used by bacteria to sense via their flagella when they are near a surface.

Transient grating spectroscopy of thermal diffusivity degradation in deuterium implanted tungsten

Using transient grating spectroscopy, we measure thermal diffusivity and surface acoustic wave speed in tungsten exposed to different fluences of deuterium plasma. Scanning electron microscopy (SEM) shows the formation of surface blisters that have similar morphology for all fluences considered. A significant reduction in thermal diffusivity and surface acoustic wave speed occurs as a result of plasma exposure. A saturation of the thermal diffusivity reduction with fluence is seen. Deuterium ion flux density appears to play a more important role in thermal diffusivity reduction than exposure time. These observations have important implications for plasma facing components in future fusion reactors.

Effectiveness of Seasonal Deer Advisories on Changeable Message Signs as a Deer Crash Mitigation Tool

The Virginia Department of Transportation began posting deer advisory messages on changeable message signs (CMSs) along a 16.7-mi segment of Interstate 64 in October 2015. The posting of these messages during the peak of deer activity, from October to November from 5 p.m. to 9 a.m., was intended to raise driver awareness and reduce the high number of deer–vehicle collisions (DVCs) in the area. The effectiveness of deer advisory messages with regard to DVC reduction is not well known. Effectiveness in this study was determined by evaluating deer carcass removal data from three October and November deer advisory posting periods. Vehicle speed evaluations were also conducted to determine whether drivers reduced speed in response to the advisories. Carcass removals were lower when the deer advisories were posted than when they were not posted, and this difference was statistically significant. During the deer advisory postings, there were statistically significant speed reductions of up to 2.8 mph at four of the five vehicle sensor stations. Speed reductions were greater when deer advisories were posted during periods of lower traffic volumes. Seasonal deer advisory messages on an interstate appear to be an effective form of DVC mitigation. Posting seasonal deer advisories every other day on the five existing CMSs in this study’s project area is expected to save approximately $700,000 to $1.4 million over the service life of the CMSs.

Multiobjective Optimisation of Bevel Gear Pair design using NSGA-II

Abstract Spiral bevel gears mesh with additional overlapping tooth action compared to straight bevels. Because of this, the transmission of motion will be smoother than that by straight bevel gears or zero bevel gears. As a result they have reduced noise and vibration, particularly occuring at high speeds. Weight reduction with simultaneous increase in transmission efficiency, by optimization method, is very much essential for gear applications which transmit very high mechanical power, with a significant reduction in speed. In many instances, in order to satisfy technical, economic and security requirements, it is essential to undertake a long development process. This research paper aims to optimize the design of a pair of spiral bevel gears, using NSGA-II, a non-dominated sorting genetic algorithm for optimization of multiple objective functions.

Effect of cigarette smoking on cognitive performance in young adult smokers

Background: Cigarette smoking represents a considerable public health burden globally. Smoking in older adults is associated with cognitive impairment and more rapid age-associated cognitive decline, but there is a paucity of studies in younger people. Hence, the study was undertaken to know the effect of cigarette smoke on cognitive functions in young healthy adults. Aims and Objectives: The aim of the study was to assess and to compare the cognitive performance in young adult smokers and non-smokers. Materials and Methods: Study was conducted between 30 male smokers (study group) and age, body mass index and education level matched (18–30 years) 30 male non-smokers (control group) based on inclusion and exclusion criteria. Subjects of both groups answered a self-reported questionnaire about smoking and personal history. Cognitive tests were done for both the groups, scores tabulated and analyzed. Results: Study group showed a significant reduction in psychomotor speed (P < 0.001) and sustained attention (P < 0.001) but no significant changes in executive functions as compared to subjects in the control group. Conclusion: Prevention of early cognitive decline in smokers has to be the top priority so as to reduce the public health burden. Awareness has to be created among smokers about the neurotoxic effects of cigarette smoke and increased risk of cognitive impairment.

T-junction priority scheme and road user’s yielding behavior

Four studies investigated yielding behavior in yield-controlled T-junctions that differed for two priority schemes. In one case road users in the intersecting arm had to give way to road users in the straight arm (priority to straight arm). In the other case road users in the straight arm had to give way to road users approaching from the intersecting arm (priority to intersecting arm). In two studies, yielding behavior was assessed with approaching speed and gaze behavior to the critical areas of the intersection. Two additional studies monitored road users’ speed and eye movements approaching the intersection. The results of the two behavioral studies showed a significant speed reduction and an increase of driver’s visual inspection to the intersection area in the priority-to-straight-arm condition in comparison to the priority-to-intersecting-arm condition. The eye movement analysis showed that total fixation time towards the intersection critical area and horizontal eye movements were significantly higher in the priority-to-straight-arm condition. The results emphasize the importance of considering perceptual affordances and expectations for priority in intersection design to increase drivers’ compliance to yielding rules.

Impact of automated photo enforcement of vehicle speed in school zones: interrupted time series analysis

ObjectiveMeasure the impact of automated photo speed enforcement in school zones on motorist speed and speeding violation rates during school travel.MethodsAutomated enforcement cameras, active during school commuting hours, were installed...

Effect of sanguinarine on biomechanics of rat airway smooth muscle cells

This study aimed to evaluate the effect of sanguinarine on biomechanical properties of rat airway smooth muscle cells (rASMCs) including stiffness, traction force and cytoskeletal stress fiber organization. To do so, rASMCs cultured in vitro were treated with sanguinarine solution at different concentrations (0.005~5 μmol/L) for 12 h, 24 h, 36 h, and 48 h, respectively. Subsequently, the cells were tested for their viability, stiffness, traction force, migration and microfilament distribution by using methylthiazolyldiphenyl-tetrazolium bromide assay, optical magnetic twisting cytometry, Fourier transform traction microscopy, scratch wound healing method, and immunofluorescence microscopy, respectively. The results showed that at concentration below 0.5 μmol/L sanguinarine had no effect on cell viability, but caused dose and time dependent effect on cell biomechanics. Specifically, rASMCs treated with sanguinarine at 0.05 μmol/L and 0.5 μmol/L for 12 and 24 h exhibited significant reduction in stiffness, traction force and migration speed, together with disorganization of the cytoskeletal stress fibers. Considering the essential role of airway smooth muscle cells (ASMCs) biomechanics in the airway hyperresponsiveness (AHR) of asthma, these findings suggest that sanguinarine may ameliorate AHR via alteration of ASMCs biomechanical properties, thus providing a novel approach for asthma drug development.

Investigation of the relationship among the microstructure, rheological properties of MR grease and the speed reduction performance of a rotary micro-brake

Abstract A magnetorheological (MR) grease-based micro-brake is proposed for providing a damping torque for a miniature turbine generator when working at high wind speeds. MR greases with a magnetic particle volume fraction from 10% to 90% are prepared for the MR grease-based micro-brake. Flow curves show that the shear thinning behaviour of MR grease is enhanced by the increased volume fraction. The zero magnetic rheological behaviour of MR grease is studied with a Herschel-Bulkley model. Then, the speed reduction effect of the MR grease-based micro-brake is experimentally studied. A rotational speed difference Δn as high as 6750 r/min is achieved by applying a current of 1.01 A to the micro-brake. MR grease with lower volume fraction demonstrates a more significant speed reduction effect under low applied currents, since the chain forming behaviour is enhanced by the decreased volume fraction. Finally, a comprehensive model for the MR grease-based micro-brake is developed to reveal the relationship among the microstructure, rheological properties of the MR grease and the speed reduction performance of the MR grease-based micro-brake.

NON‐CONTACT ELECTRIC FIELDS POTENTLY HINDER EGF PROMOTED BREAST CANCER MOTILITY BY DOWNREGULATING EGFR PHOSPHORYLATION

The objective of the proposed study is to assess the therapeutic potential of non‐contact inductive E‐fields (iEFs) in inhibiting breast cancer motility. Normal breast ducts are lined with monolayer of epithelial cells that have asymmetric distribution of ion channels resulting in a charge separation between the luminal and the basal sides giving rise to trans‐epithelial potentials (TEP). These TEPs are responsible for endogenous E‐fields that are directed radially from luminal to basal side. Consequently, the sites of invasion in breast tumors are depolarized, which suggest that that cell migration in late‐stage tumors occurs in absence of endogenous E‐fields. Furthermore, breast cancer cells in‐vitro have been shown to migrate towards the positive electrodes under the influence of externally applied direct current electric fields (1–10 V/cm). Therefore, we hypothesize that E‐fields applied in the direction of migrating breast cancer cells potently inhibit cell motility. To test our hypothesis, we used a panel of three breast cell lines, 1) normal MCF10A, 2) MCF10CA1a(MIV) (a malignant variant of MCF10A cells with H‐Ras mutation), and 3) triple negative breast cancer (TNBC) cells MDA‐MB‐231 in conjunction with a custom Bi‐directional Microtrack Assay (BMA). The BMA consists of an array of parallel‐aligned tracks that measure 700 μm in length and with a cross‐section of 20 μm × 20 μm. These microtracks mimic the topological cues encountered by migrating tumor cells that have detached from the primary tumor site during invasion. Inductive Electric Fields (iEFs ~ 60 μV/cm), which mimic the endogenous E‐fields in the breast duct, were applied using a custom‐designed air‐cored Helmholtz coils. iEFs applied anti‐parallel to the direction of migration and in absence of a pro‐migratory epidermal growth factor (EGF) gradient on cancer cells significantly increased migration speeds (Fig A) but had no effect on the control epithelial cells which maintained their non‐migratory phenotype. In presence of a stable EGF gradient, iEFs applied parallel in the direction of migration significantly reduce migration speeds for both the cancerous cell lines whereas it has no effect on migration speeds of MCF10A cells. Actin aggregation at the leading and/or trailing edges is a characteristic of migratory cells and for cancer cells that showed significant speed reduction the intracellular actin was uniformly distributed (Fig B) rather aggregating on the tips indicating a possible mechanism controlled through the EGFR/EGF pathway. Furthermore, we verified using Western Blotting techniques that iEFs significantly reduced phosphorylation of EGFR in EGF‐treated MDA‐MB‐231 cells (Fig C) whereas they downregulated the expression of EGFR in EGF‐treated MCF10CA1a(MIV) cells. For each case, the protein levels had a one‐to‐one correlation with the migration speeds for each cell line. Moreover, we also found that a combinatorial treatment of MK2206 (Akt inhibitor) with iEFs significantly reduced migration speeds of these breast cancer cells (Fig A) below the level of their respective controls. Thus, iEFs selectively hindered cancer cells with no adverse effects on normal epithelial cells, making them a potential candidate for cancer control and intervention. From a therapeutic standpoint, iEFs may help augment current therapeutic approaches to hinder the metastasis of breast cancer and confer survival benefit, including in TNBC, which currently lack any targeted therapies.Support or Funding InformationFunding for JWS: American Cancer Society and Institute for Materials Research at The Ohio State University. JWS acknowledge support from Pelotonia.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Improving the performance of galloping micro-power generators by passively manipulating the trailing edge

Recent trends in distributed sensing networks have generated significant interest in the design of scalable micro-power generators. One such device exploits the galloping oscillations of a prism to harness energy from a moving fluid. Performance of galloping harvester's depends on the flow patterns around the prism, which, in turn, depend on its geometry and the Reynolds number of the flow. In this letter, we demonstrate that the useful range of the galloping instability can be extended by attaching a rigid splitter plate to the rear face of the prism. The plate provides a secondary flow reattachment point, which serves to improve the oscillation amplitude and power output of the generator. Experimental results demonstrate as much as 67% power enhancement for some prism geometries and a significant reduction in the cut-in wind speed of the generator.

A Comparative Study on Fatigue Damage using a Wave Load Sequence Model

Despite that ships get the approval of classification societies and structural members are designed to survive random environmental conditions for twenty or twenty-five years, fatigue crack damage still occurs. Nowadays, the operation based on weather routing programs has become important, not only to avoid adverse sea conditions that can cause damage, time loss or significant speed reduction but also to improve the crew safety. In this paper, S-N based fatigue assessment of a welded joint in an ocean going is performed. It is assumed that the ship sails following a planned route and a route based on weather conditions. Short sea sequences are generated by a storm model called “4G Storm Model”, proposed by one of the co-authors (De Gracia et al., 2017). Stress histories are generated considering the stochastical nature of the wave direction variation. Cumulative fatigue damage is performed following a classification society rule. Based on these results, the effect of ship routing and headings model on the S-N fatigue assessment is discussed. Keywords: Weather routing, fatigue, cumulative damage, storm model, wave sequence model.

Reducing Vehicle Collisions With the Central American Tapir in Central Belize District, Belize

The Central American tapir Tapirus bairdii is the national animal of Belize. Accidents from vehicle collisions pose a new threat to the species. A total of 14 tapir deaths were recorded from June 2008 through December 2012 in Central Belize District. Two areas were identified as hot spots for tapir-vehicle collisions (TVCs), and spot-speed surveys revealed speeding to be common in that area. More than 47% of the vehicles were traveling above the prescribed speed limit, and another 28% were driving at speeds of 100 kph or faster. In an effort to reduce speed and the risk of TVCs, we deployed two sets of reflective wildlife crossing signs over a 6-km stretch of road. This was followed by an awareness campaign alerting drivers of tapirs’ presence in the area. We saw a significant reduction in speed immediately after the installation of the warning signs, and no TVCs were recorded for the next 10 months. Consequently, camera-trapping and track surveys were undertaken to confirm the species continued presence in the immediate area. Over the next 2 years, only two collisions were recorded along the same stretch of road.

Finite element analysis of high aspect ratio wind tunnel wing model: A parametric study

Procedure for designing the wind tunnel model of a high aspect ratio (HAR) wing containing geometric nonlinearities is described in this paper. The design process begins with identification of basic features of the HAR wing as well as its design constraints. This enables the design space to be narrowed down and consequently, brings ease of convergence towards the design solution. Parametric studies in terms of the spar thickness, the span length and the store diameter are performed using finite element analysis for both undeformed and deformed cases, which respectively demonstrate the linear and nonlinear conditions. Two main criteria are accounted for in the selection of the wing design: the static deflections due to gravitational loading should be within the allowable margin of the size of the wind tunnel test section and the flutter speed of the wing should be much below the maximum speed of the wind tunnel. The findings show that the wing experiences a stiffness hardening effect under the nonlinear static solution and the presence of the store enables significant reduction in linear flutter speed.

Adaptation of a smart walker for stroke individuals: a study on sEMG and accelerometer signals

Abstract Introduction: Stroke is a leading cause of neuromuscular system damages, and researchers have been studying and developing robotic devices to assist affected people. Depending on the damage extension, the gait of these people can be impaired, making devices, such as smart walkers, useful for rehabilitation. The goal of this work is to analyze changes in muscle patterns on the paretic limb during free and walker-assisted gaits in stroke individuals, through accelerometry and surface electromyography (sEMG). Methods The analyzed muscles were vastus medialis, biceps femoris, tibialis anterior and gastrocnemius medialis. The volunteers walked three times on a straight path in free gait and, further, three times again, but now using the smart walker, to help them with the movements. Then, the data from gait pattern and muscle signals collected by sEMG and accelerometers were analyzed and statistical analyses were applied. Results The accelerometry allowed gait phase identification (stance and swing), and sEMG provided information about muscle pattern variations, which were detected in vastus medialis (onset and offset; p = 0.022) and biceps femoris (offset; p = 0.025). Additionally, comparisons between free and walker-assisted gaits showed significant reduction in speed (from 0.45 to 0.30 m/s; p = 0.021) and longer stance phase (from 54.75 to 60.34%; p = 0.008). Conclusions Variations in muscle patterns were detected in vastus medialis and biceps femoris during the experiments, besides user speed reduction and longer stance phase when the walker-assisted gait is compared with the free gait.

Reducing the threat of wildlife-vehicle collisions during peak tourism periods using a Roadside Animal Detection System

Roadside Animal Detection Systems (RADS) aim to reduce the frequency of wildlife-vehicle collisions. Unlike fencing and wildlife passages, RADS do not attempt to keep animals off the road; rather, they attempt to modify driver behavior by detecting animals near the road and warning drivers with flashing signs. A RADS was installed in Big Cypress National Park (Florida, USA) in 2012 in response to an increased number of Florida panther mortalities. To assess driver response, we measured the speed of individual cars on the road when the RADS was active (flashing) and inactive (not flashing) during the tourist season (November–March) and the off-season (April–October), which vary dramatically in traffic volume. We also used track beds and camera traps to assess whether roadside activity of large mammal species varied between seasons. In the tourist season, the activation of the RADS caused a significant reduction in vehicle speed. However, this effect was not observed in the off-season. Track and camera data showed that the tourist season coincided with peak periods of activity for several large mammals of conservation interest. Drivers in the tourist season generally drove faster than those in the off-season, so a reduction in speed in response to the RADS is more beneficial in the tourist season. Because traffic volume and roadside activity of several species of conservation interest both peak during the tourist season, our study indicates that the RADS has the potential to reduce the number of accidents during this period of heightened risk.

Feasibility of a Powered Knee Joint in Providing Stance and Swing Phase Knee Flexion when Using a Knee-Ankle-Foot Orthosis

ABSTRACT Background The aim of this study was to develop a new stance control knee-ankle-foot orthosis (SCKAFO) and determine its efficacy on specific spatiotemporal and kinematic parameters. Method Seven healthy volunteer subjects participated in this study. After orthotic gait training, subjects participated in a four-part data collection session that consisted of gait evaluation with normal walking, SCKAFO with locked knee joint, SCKAFO without initial flexion (IF) mode, and SCKAFO with IF mode. Results Walking with any of the control knee-ankle-foot orthoses (KAFOs) produced a significant reduction in walking speed compared with normal walking. There was no significant difference in walking speed between the SCKAFO with and without IF. There was significantly higher knee flexion in stance phase when walking with the SCKAFO with IF compared with the other types of KAFO, but there was no significant difference between normal walking and SCKAFO with IF. In wearing SCKAFO with IF, the mean of the hip flexion was not significantly altered compared with normal walking. Hip abduction was also significantly reduced during walking with stance control (SC) mode compared to KAFO with locked knee joint. Conclusion Knee-ankle-foot orthosis with new powered knee joint has benefits over existing assistive KAFOs with locked and SC knee joints.

Multimodal communication in courting fiddler crabs reveals male performance capacities.

Courting males often perform different behavioural displays that demonstrate aspects of their quality. Male fiddler crabs, Uca sp., are well known for their repetitive claw-waving display during courtship. However, in some species, males produce an additional signal by rapidly stridulating their claw, creating a ‘drumming’ vibrational signal through the substrate as a female approaches, and even continue to drum once inside their burrow. Here, we show that the switch from waving to drumming might provide additional information to the female about the quality of a male, and the properties of his burrow (multiple message hypothesis). Across males there was, however, a strong positive relationship between aspects of their waving and drumming displays, suggesting that drumming adheres to some predictions of the redundant signal hypothesis for multimodal signalling. In field experiments, we show that recent courtship is associated with a significant reduction in male sprint speed, which is commensurate with an oxygen debt. Even so, males that wave and drum more vigorously than their counterparts have a higher sprint speed. Drumming appears to be an energetically costly multimodal display of quality that females should attend to when making their mate choice decisions.

Pacing Strategy During 24-Hour Ultramarathon-Distance Running.

To describe pacing strategy in a 24-h running race and its interaction with sex, age group, athletes' performance group, and race edition. Data from 398 male and 103 female participants of 5 editions were obtained based on a minimum 19.2-h effective-running cutoff. Mean running speed from each hour was normalized to the 24-h mean speed for analyses. Mean overall performance was 135.6 ± 33.0 km with a mean effective-running time of 22.4 ± 1.3 h. Overall data showed a reverse J-shaped pacing strategy, with a significant reduction in speed from the second-to-last to the last hour. Two-way mixed ANOVAs showed significant interactions between racing time and both athlete performance group (F = 7.01, P < .001, ηp2 = .04) and race edition (F = 3.01, P < .001, ηp2 = .02) but not between racing time and either sex (F = 1.57, P = .058, ηp 2 < .01) or age group (F = 1.25, P = .053, ηp2 = .01). Pearson product-moment correlations showed an inverse moderate association between performance and normalized mean running speed in the first 2 h (r = -.58, P < .001) but not in the last 2 h (r = .03, P = .480). While the general behavior represents a rough reverse J-shaped pattern, the fastest runners start at lower relative intensities and display a more even pacing strategy than slower runners. The "herd behavior" seems to interfere with pacing strategy across editions, but not sex or age group of runners.