A COMPARISON OF HAND FORCE AND STARTING BLOCK-BASED RESPONSE TIMES IN THE SPRINT START

This study provided a method comparison of sprint start response times (RTs) obtained using a custom designed hand force plate with block response-times (RT) from anInternational Association of Athletic Federation (IAAF) approved automatic start control system (IAAF RT). Twenty national and international sprinters completed sprint trials under simulated race conditions. The athletes’ hand forces were obtained using the hand force plate, which was electronically synchronised with the IAAF approved system. The results showed that in all trials, the hand plate RT occurred significantly before the IAAF RT with an average difference of 64 ms. The consistent differences in RT’s suggested that the two systems measured separate events. A re-evaluation of false start detection technology based on measuring hand RT is recommended

A METHOD COMPARISON STUDY OF ACCELEROMETER BASED BLOCK RESPONSE TIMES IN SPRINTING

This study aimed to provide a method comparison of a rail mounted accelerometer for detection of block response-times (RT) with an International Association of Athletic Federation (IAAF) approved automatic start control system (IAAF RT). Twenty national and international sprinters completed sprint trials under simulated race conditions. An accelerometer was placed on the block rail of blocks and RT was determined using visual inspection of the accelerometer signal and using a 3SD threshold method. On average, the visual method detected the RT event 7 ms before, and the 3SD method detected RT 1 ms after the IAAF RT. The results indicated close agreement between the 3SD threshold method and the IAAF RT, however, this highlights the need for further re-examination of threshold-based detection algorithms which may delay the detection of the RT event

Canalization and Symmetry in Boolean Models for Genetic Regulatory Networks

Canalization of genetic regulatory networks has been argued to be favored by evolutionary processes due to the stability that it can confer to phenotype expression. We explore whether a significant amount of canalization and partial canalization can arise in purely random networks in the absence of evolutionary pressures. We use a mapping of the Boolean functions in the Kauffman N-K model for genetic regulatory networks onto a k-dimensional Ising hypercube to show that the functions can be divided into different classes strictly due to geometrical constraints. The classes can be counted and their properties determined using results from group theory and isomer chemistry. We demonstrate that partially canalized functions completely dominate all possible Boolean functions, particularly for higher k. This indicates that partial canalization is extremely common, even in randomly chosen networks, and has implications for how much information can be obtained in experiments on native state genetic regulatory networks.Comment: 14 pages, 4 figures; version to appear in J. Phys.

FUNCTIONAL DATA ANALYSIS OF THE KINEMATICS OF GAIT IN SUBJECTS WITH A HISTORY OF ACHILLES TENDON INJURY

Clinical biomechanics research aims to understand the mechanisms of injury to improve prediction, prevention and rehabilitation. Dynamical systems theory suggests that coordination and variability may be key issues in the development of injuries. Traditional analysis has relied on a multivariate approach using discrete measures during stance. This essentially discards kinematic data obtained throughout the entire stance phase. Functional data analysis is an established statistical technique that is now emerging in biomechanics. It views the data as a function, thus using the entire time series data and determines which factors contribute to the variation. The purpose of this study was to examine the predictions of dynamical systems theory on angular kinematic data in subjects with Achilles tendon injury using a functional data analysis approach

Visual Advantage of Enhanced Flight Vision System During NextGen Flight Test Evaluation

Synthetic Vision Systems and Enhanced Flight Vision System (SVS/EFVS) technologies have the potential to provide additional margins of safety for aircrew performance and enable operational improvements for low visibility operations in the terminal area environment. Simulation and flight tests were jointly sponsored by NASA's Aviation Safety Program, Vehicle Systems Safety Technology project and the Federal Aviation Administration (FAA) to evaluate potential safety and operational benefits of SVS/EFVS technologies in low visibility Next Generation Air Transportation System (NextGen) operations. The flight tests were conducted by a team of Honeywell, Gulfstream Aerospace Corporation and NASA personnel with the goal of obtaining pilot-in-the-loop test data for flight validation, verification, and demonstration of selected SVS/EFVS operational and system-level performance capabilities. Nine test flights were flown in Gulfstream's G450 flight test aircraft outfitted with the SVS/EFVS technologies under low visibility instrument meteorological conditions. Evaluation pilots flew 108 approaches in low visibility weather conditions (600 feet to 3600 feet reported visibility) under different obscurants (mist, fog, drizzle fog, frozen fog) and sky cover (broken, overcast). Flight test videos were evaluated at three different altitudes (decision altitude, 100 feet radar altitude, and touchdown) to determine the visual advantage afforded to the pilot using the EFVS/Forward-Looking InfraRed (FLIR) imagery compared to natural vision. Results indicate the EFVS provided a visual advantage of two to three times over that of the out-the-window (OTW) view. The EFVS allowed pilots to view the runway environment, specifically runway lights, before they would be able to OTW with natural vision

The Swift/BAT AGN Spectroscopic Survey (BASS) -- VI. The Gamma_X - L/L_Edd relation

We study the observed relation between accretion rate (in terms of L/L_Edd) and shape of the hard X-ray spectral energy distribution (namely the photon index Gamma_X) for a large sample of 228 hard X-ray selected, low-redshift active galactic nuclei (AGN), drawn from the Swift/BAT AGN Spectroscopic Survey (BASS). This includes 30 AGN for which black hole mass (and therefore L/L_Edd) is measured directly through masers, spatially resolved gas or stellar dynamics, or reverberation mapping. The high quality and broad energy coverage of the data provided through BASS allow us to examine several alternative determinations of both Gamma_X and L/L_Edd. For the BASS sample as a whole, we find a statistically significant, albeit very weak correlation between Gamma_X and L/L_Edd. The best-fitting relations we find, Gamma_X=0.15 log(L/L_Edd)+const., are considerably shallower than those reported in previous studies. Moreover, we find no corresponding correlations among the subsets of AGN with different M_BH determination methodology. In particular, we find no robust evidence for a correlation when considering only those AGN with direct or single-epoch M_BH estimates. This latter finding is in contrast to several previous studies which focused on z>0.5 broad-line AGN. We discuss this tension and conclude that it can be partially accounted for if one adopts a simplified, power-law X-ray spectral model, combined with L/L_Edd estimates that are based on the continuum emission and on single-epoch broad line spectroscopy in the optical regime. We finally highlight the limitations on using Gamma_X as a probe of supermassive black hole evolution in deep extragalactic X-ray surveys.Comment: Resubmitted to MNRAS after addressing referee's comment

Spatio-temporal expression patterns of Arabidopsis thaliana and Medicago truncatula defensin-like genes

Plant genomes contain several hundred defensin-like (DEFL) genes that encode short cysteine-rich proteins resembling defensins, which are well known antimicrobial polypeptides. Little is known about the expression patterns or functions of many DEFLs because most were discovered recently and hence are not well represented on standard microarrays. We designed a custom Affymetrix chip consisting of probe sets for 317 and 684 DEFLs from Arabidopsis thaliana and Medicago truncatula, respectively for cataloging DEFL expression in a variety of plant organs at different developmental stages and during symbiotic and pathogenic associations. The microarray analysis provided evidence for the transcription of 71% and 90% of the DEFLs identified in Arabidopsis and Medicago, respectively, including many of the recently annotated DEFL genes that previously lacked expression information. Both model plants contain a subset of DEFLs specifically expressed in seeds or fruits. A few DEFLs, including some plant defensins, were significantly up-regulated in Arabidopsis leaves inoculated with Alternaria brassicicola or Pseudomonas syringae pathogens. Among these, some were dependent on jasmonic acid signaling or were associated with specific types of immune responses. There were notable differences in DEFL gene expression patterns between Arabidopsis and Medicago, as the majority of Arabidopsis DEFLs were expressed in inflorescences, while only a few exhibited root-enhanced expression. By contrast, Medicago DEFLs were most prominently expressed in nitrogen-fixing root nodules. Thus, our data document salient differences in DEFL temporal and spatial expression between Arabidopsis and Medicago, suggesting distinct signaling routes and distinct roles for these proteins in the two plant species

Ex-nihilo II: Examination Syllabi and the Sequencing of Cosmology Education

Cosmology education has become an integral part of modern physics courses. Directed by National Curricula, major UK examination boards have developed syllabi that contain explicit statements about the model of the Big Bang and the strong observational evidence that supports it. This work examines the similarities and differences in these specifications, addresses when cosmology could be taught within a physics course, what should be included in this teaching and in what sequence it should be taught at different levels.Comment: 9 pages. Accepted for publication in a special issue of Physics Educatio

Detection of anaplasma bovis in an undecribed tick species collected from the eastern rock sengi Elephantulus myurus

Ticks are important vectors of numerous pathogens causing illness, fatalities, and economic loss worldwide. Infectious disease episodes are increasing, and novel tick-borne pathogens are described frequently. Identification of novel reservoir hosts and vectors of tick-borne pathogens is essential if control measures are to be successful. In South Africa, the eastern rock sengi, Elephantulus myurus, hosts a number of tick species of veterinary importance. Despite this, there remains a paucity of information regarding the tick fauna of this species, the pathogen associations of ticks that it hosts, and its role as a reservoir host of tick-borne pathogens. The current study documents the tick fauna of E. myurus and sympatric small mammal species in Limpopo Province, South Africa. The pathogen associations of ticks hosted by elephant shrews were also investigated by PCR screening of engorged nymphs for a broad range of bacterial and protozoan tick-borne infections, including Borrelia burgdorferi sensu lato and members of Apicomplexa and the order Rickettsiales. There were marked differences in tick species and abundance among host species. Elephantulus myurus was heavily, and predominantly, parasitized by an as-yet undescribed tick species that we identify as Rhipicephalus sp. near warburtoni. PCR and sequence analysis revealed the presence of Anaplasma bovis in this tick species, which may have consequences for livestock production and conservation efforts in the area where this tick species occurs.A British Ecological Society Small Ecological Project Grant (2353/2909) awarded to A. Harrison and a National Research Foundation grant to I. G. Horak.http://asp.unl.edu/index.php?option=com_content&view=article&id=39&Itemid=48ab201