BACKGROUND All-terrain vehicles (ATVs) are unstable on steep and rough terrain, and thus, rollover is the most common accident which can result in a high rate of fatal outcomes, with higher rates for young and male drivers. OBJECTIVE This paper investigates the ability of rural Pennsylvania ATV drivers to correctly evaluate slopes, and the mean slope angle at which the most and least conserva...

Observers used a cursor to mark the location and polarity of all the bar and edge features seen in compound (f + 3f) gratings of moderate frequency and contrast. They almost always reported six bars and six edges per cycle of the fundamental frequency (f = 0.4 c/deg, contrast 32%), for all phases of the third harmonic (3f = 1.2 c/deg, contrast 10.7%). This general pattern of features was predic...

To assess energetic costs during rest and locomotion in a small insect, we measured metabolic rate in freely moving ants Camponotus sp. (average body mass 11.9 mg). The animals ran in a straight respirometric chamber in which locomotor speed and CO2 release were monitored simultaneously using flow-through respirometry and conventional video analysis. In resting intact ants, standard metabolic r...

Fifty-two of 95 smokers with a forced expiratory volume in one second (FEV1) above 70% predicted and with chronic bronchitis were found to have increased bronchial responsiveness, expressed as PC20FEV1, upon challenge with inhaled histamine. The degree of responsiveness was significantly below that found in matched asthmatics, but substantially higher than that reported in normals. The degree o...

Localization within the space in front of an observer can be specified along two orthogonal physical dimensions: elevation ('up', 'down') and horizontal ('left','right'). For the erect observer, these correspond to egocentric dimensions along the long and short axes of the body, respectively. However, when subjects are rolled-to-horizontal (lying on their sides), the correspondence between the ...

A graph is outer 1-planar if it admits a drawing where each vertex is on the outer face and each edge is crossed by at most another edge. Outer 1-planar graphs are a superclass of the outerplanar graphs and a subclass of the planar partial 3-trees. We show that an outer 1-planar graph G of bounded degree ∆ admits an outer 1-planar straight-line drawing that uses O(∆) different slopes, which gen...

We analyzed footprints on the surface of a sand dune to estimate maximal running speeds and the incidence of bipedality in nature, as well as to investigate the effects of incline on the escape locomotion of the lizard Callisaurus draconoides. Previous laboratory tests predicted that inclines would negatively affect sprinting performance in C. draconoides. Although physiologists commonly assume...

The purpose of this study was to determine the effect of cross-slope on gait dynamics. Ten young adult males walked barefoot along an inclinable walkway. Ground reaction forces (GRFs), lower-limb joint kinematics, global pelvis orientation, functional leg-length, and joint reaction moments (JRMs) were measured. Statistical analyses revealed differences across limbs (up-slope [US] and down-slope...

Although previous laboratory studies have commonly determined sprinting speeds of lizards on horizontal surfaces, the speeds and slopes used during the escapes of lizards in natural habitats with variable inclines are virtually unstudied. To quantify performance and the use of inclined surfaces during escape, we took advantage of the footprints left in soft substrate and the simple surface topo...

The authors examined the effects of locomotor experience on infants' perceptual judgments in a potentially risky situation--descending steep and shallow slopes--while manipulating social incentives to determine where perceptual judgments are most malleable. Twelve-month-old experienced crawlers and novice walkers were tested on an adjustable sloping walkway as their mothers encouraged and disco...