16,283 research outputs found
Demographic and psychological variables affecting test subject evaluations of ride quality
Ride-quality experiments similar in objectives, design, and procedure were conducted, one using the U.S. Air Force Total In-Flight Simulator and the other using the Langley Passenger Ride Quality Apparatus to provide the motion environments. Large samples (80 or more per experiment) of test subjects were recruited from the Tidewater Virginia area and asked to rate the comfort (on a 7-point scale) of random aircraft motion typical of that encountered during STOL flights. Test subject characteristics of age, sex, and previous flying history (number of previous airplane flights) were studied in a two by three by three factorial design. Correlations were computed between one dependent measure, the subject's mean comfort rating, and various demographic characteristics, attitudinal variables, and the scores on Spielberger's State-Trait Anxiety Inventory. An effect of sex was found in one of the studies. Males made higher (more uncomfortable) ratings of the ride than females. Age and number of previous flights were not significantly related to comfort ratings. No significant interactions between the variables of age, sex, or previous number of flights were observed
Umbral Moonshine and the Niemeier Lattices
In this paper we relate umbral moonshine to the Niemeier lattices: the 23
even unimodular positive-definite lattices of rank 24 with non-trivial root
systems. To each Niemeier lattice we attach a finite group by considering a
naturally defined quotient of the lattice automorphism group, and for each
conjugacy class of each of these groups we identify a vector-valued mock
modular form whose components coincide with mock theta functions of Ramanujan
in many cases. This leads to the umbral moonshine conjecture, stating that an
infinite-dimensional module is assigned to each of the Niemeier lattices in
such a way that the associated graded trace functions are mock modular forms of
a distinguished nature. These constructions and conjectures extend those of our
earlier paper, and in particular include the Mathieu moonshine observed by
Eguchi-Ooguri-Tachikawa as a special case. Our analysis also highlights a
correspondence between genus zero groups and Niemeier lattices. As a part of
this relation we recognise the Coxeter numbers of Niemeier root systems with a
type A component as exactly those levels for which the corresponding classical
modular curve has genus zero.Comment: 181 pages including 95 pages of Appendices; journal version, minor
typos corrected, Research in the Mathematical Sciences, 2014, vol.
Consistency of pacing and metabolic responses during 2000-m rowing ergometry
PURPOSE: This study investigated the pacing strategy adopted and the consistency of performance and related physiological parameters across three 2000-m rowing-ergometer tests.
METHODS: Fourteen male well-trained rowers took part in the study. Each participant performed three 2000-m rowing-ergometer tests interspersed by 3-7 d. Throughout the trials, respiratory exchange and heart rate were recorded and power output and stroke rate were analyzed over each 500 m of the test. At the completion of the trial, assessments of blood lactate and rating of perceived exertion were measured.
RESULTS: Ergometer performance was unchanged across the 3 trials; however, pacing strategy changed from trial 1, which featured a higher starting power output and more progressive decrease in power, to trials 2 and 3, which were characterized by a more conservative start and an end spurt with increased power output during the final 500 m. Mean typical error (TE; %) across the three 2000-m trials was 2.4%, and variability was low to moderate for all assessed physiological variables (TE range = 1.4-5.1%) with the exception of peak lactate (TE = 11.5%).
CONCLUSIONS: Performance and physiological responses during 2000-m rowing ergometry were found to be consistent over 3 trials. The variations observed in pacing strategy between trial 1 and trials 2 and 3 suggest that a habituation trial is required before an intervention study and that participants move from a positive to a reverse-J-shaped strategy, which may partly explain conflicting reports in the pacing strategy exhibited during 2000-m rowing-ergometer trials
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