Analysis of repeated high-intensity running performance in professional soccer

The aims of this study conducted in a professional soccer team were two-fold: to characterise repeated high-intensity movement activity profiles in official match-play; b) to inform and verify the construct validity of tests commonly used to determine repeated-sprint ability in soccer by investigating the relationship between the results from a test of repeated-sprint ability and repeated high-intensity performance in competition. High-intensity running performance (movement at velocities >19.8 km/h for a minimum of 1-s duration) in 20 players was measured using computerised time motion analysis. Performance in 80 French League 1 matches was analysed. In addition, 12 out of the 20 players performed a repeated-sprint test on a non-motorized treadmill consisting of 6 consecutive 6s sprints separated by 20s passive recovery intervals. In all players, the majority of consecutive high-intensity actions in competition were performed after recovery durations ≥61s, recovery activity separating these efforts was generally active in nature with the major part of this spent walking, and players performed 1.1±1.1 repeated high-intensity bouts (a minimum of 3 consecutive high-intensity with a mean recovery time ≤20s separating efforts) per game. Players reporting lowest performance decrements in the repeated-sprint ability test performed more high-intensity actions interspersed by short recovery times (≤20s, p<0.01 and ≤30s, p<0.05) compared to those with higher decrements. Across positional roles, central-midfielders performed a greater number of high-intensity actions separated by short recovery times (≤20s) and spent a larger proportion of time running at higher intensities during recovery periods while fullbacks performed the most repeated high-intensity bouts (statistical differences across positional roles from p<0.05 to p<0.001). These findings have implications for repeated high-intensity testing and physical conditioning regimens

Experimental study of the turbulent boundary layer in acceleration-skewed oscillatory flow

Peer reviewedPublisher PD

Experimental study of bore-driven swash hydrodynamics on impermeable rough slopes

Copyright 2012 Elsevier B.V., All rights reserved.Peer reviewedPublisher PD

GeneRepair - A Repair Operator for Genetic Algorithms

In this paper we present the outcome of two recent sets of experiments to evaluate the effectiveness of a new adjunct genetic operator GeneRepair. This operator was developed to correct invlaid tours which may be generated following crossover or mutation of our particular implementation of the genetic algorithm. Following implementation and testing of our genetic algotihm with GeneRepair we found a significant positive side in our results. Using GeneRepair along side traditional corsover and mutation operators we have been able to travers the search space of a problem and generate very good results in an extremely efficent manner, in both time and number of evaluations required

Infections by Kudoa ciliatae (Myxozoa: Myxosporea) in Indo-Pacific whiting Sillago spp.

Infections by Kudoa ciliatae Lom, Rohde & Dykova, 1992 were detected in 141 (32%) of 444 Indo-Pacific whiting Sillago spp, caught in Moreton Bay, Australia. The parasite was detected in the type host, S. ciliata (in 14% of 73 fish), and from 2 new hosts, S, maculata (46% of 264) and S. analis (9% of 107). Prevalence of infection in S. maculata was greatest in autumn (100%) and lowest in spring (10%), the seasonal differences being positively correlated to host size (more prevalent in larger fish caught in autumn). Intensity of infection ranged from 1 to 45 cysts per fish (mean 7.6) and the cysts measured up to 2.5 mm in length. Most cysts were located on the serosal surface of the intestinal tract extending into the circular smooth muscle layer. The majority were found in the distal third of the intestine, often in groups of 2 to 5 cysts. Parasites were also found for the first time in the pyloric caeca, intestinal mesentery and liver. Calcified cysts were occasionally detected in S, ciliata and S, analis

The unusual pulsation spectrum of the cool ZZ Ceti star HS 0507+0434B

We present the analysis of one week of single-site high-speed CCD photometric observations of the cool ZZ Ceti star HS 0507+0434B. Ten independent frequencies are detected in the star's light variations: one singlet and three nearly-equally spaced triplets. We argue that these triplets are due to rotationally split modes of spherical degree l=1. This is the first detection of consistent multiplet structure in the amplitude spectrum of a cool ZZ Ceti star and it allows us to determine the star's rotation period: 1.70 +/- 0.11 d. We report exactly equal frequency, not period, spacings between the detected mode groups. In addition, certain pairs of modes from the four principal groups have frequency ratios which are very close to 3:4 or 4:5; while these ratios are nearly exact (within one part in 10^4), they still lie outside the computed error bars. We speculate that these relationships between different frequencies could be caused by resonances. One of the three triplets may not be constant in amplitude and/or frequency. We compare our frequency solution for the combination frequencies (of which we detected 38) to Wu's (1998, 2001) model thereof. We obtain consistent results when trying to infer the star's convective thermal time and the inclination angle of its rotational axis. Theoretical combination-frequency amplitude spectra also resemble those of the observations well, and direct theoretical predictions of the observed second-order light-curve distortions were also reasonably successful assuming the three triplets are due to l=1 modes. Attempts to reproduce the observed combination frequencies adopting all possible l=2 identifications for the triplets did not provide similarly consistent results, supporting their identification with l=1.Comment: Accepted for publication in MNRAS; 12 pages, 8 figure

An expanded phylogeny of the Entodiniomorphida (Ciliophora : Litostomatea)

The Entodiniomorphida are a diverse and morphologically complex group of ciliates which are symbiotic within the digestive tracts of herbivorous mammals. Previous phylogenies of the group have exclusively considered members of one family, the Ophryoscolecidae, which are symbiotic within ruminants. We sought to improve understanding of evolution within the entodiniomorphs by expanding the range of ciliates examined to include the Cycloposthiidae and Macropodimidae (symbionts of equids and macropodids respectively). The entire SSU-rRNA gene was sequenced for 3 species, Cycloposthium edentatum, Macropodinium ennuensis and M. yalanbense, and aligned against 14 litostome species and 2 postciliodesmatophoran outgroup species. Cycloposthium was consistently grouped as the sister-taxon to the Ophryoscolecidae although support for this relationship was low. This suggests that there is more evolutionary distance between the Cycloposthiidae and Ophryoscolecidae than previously inferred from studies of gross morphology, cell ontogeny or ultrastructure. In contrast, Macropodinium did not group with any of the entodiniomorphs, instead forming the sister group to the entire Trichostomatia (Entodiniomorphida + Vestibuliferida). This early diverging position for the macropodiniids is concordant with their morphology and ontogeny which failed to group the family with any of the entodiniomorph suborders. The currently accepted classification of the Trichostomatia is thus deficient and in need of review