7,693 research outputs found
Relationship between physical capacity and match performance in semiprofessional Australian rules football
This study investigated the relationship between physical performance and match performance in Australian Rules Football (ARF). Thirty-six semiprofessional ARF players participated in this study. Physical capacity was measured using a 3-km time trial. Match performance was measured throughout the 2013 season through 2 methods: direct game involvements (DGIs) per minute and a recording of coaches\u27 vote after the game. The main finding of the study was that 3-km time trial performance was a significant predictor of DGI per minute (p ≤ 0.05). In addition, the number of senior games played was also significant in predicting DGI per minute (p ≤ 0.05). Furthermore, the number of senior games significantly correlated with coaches\u27 votes (p ≤ 0.05). There were no significant relationships between 3-km time trial and coaches\u27 vote. The results highlight the importance of developing physical capacity in the preseason period; the players who were better performers in the 3-km time trial had a greater number of DGIs per minute. This information is important to consider in preseason planning to ensure sufficient time is dedicated to developing physical capacity in the training program, as it is directly associated with performance. In addition, this research also highlights the importance of playing experience in relation to team selection. Playing experience, as measured by the number of senior games played, had a significant relationship with both measures of match performance
Reversible Three-State Switching of Luminescence: A New Twist to Electro- and Photochromic Behavior
Testing a global city hypothesis : an assessment of polarization across US cities
Social polarization is perhaps most evident within the world's large cities where we can easily observe stark contrasts between wealth and poverty. A world city theoretical perspective has emerged that associates large cities importance in a global network of cities to the degree of internal polarization within these cities. The research reported here locates 57 large US cities within this world city hierarchy and then empirically examines the hypothesized positive association between global centrality and social polarization using a multivariate, cross-city analysis. The findings are mixed, with some evidence that global centrality increases income polarization, but only in the context of higher levels of immigration. There is no evidence that a city's centrality affects occupational polarization. We conclude by suggesting implications for the world city literature and future research
Cool White Dwarfs Revisited -- New Spectroscopy and Photometry
In this paper we present new and improved data on 38 cool white dwarfs
identified by Oppenheimer et al. 2001 (OHDHS) as candidate dark halo objects.
Using the high-res spectra obtained with LRIS, we measure radial velocities for
13 WDs that show an H alpha line. We show that the knowledge of RVs decreases
the UV-plane velocities by only 6%. The radial velocity sample has a W-velocity
dispersion of sig_W = 59 km/s--in between the values associated with the thick
disk and the stellar halo. We also see indications for the presence of two
populations by analyzing the velocities in the UV plane. In addition, we
present CCD photometry for half of the sample, and with it recalibrate the
photographic photometry of the remaining WDs. Using the new photometry in
standard bands, and by applying the appropriate color-magnitude relations for H
and He atmospheres, we obtain new distance estimates. New distances of the WDs
that were not originally selected as halo candidates yield 13 new candidates.
On average, new distances produce velocities in the UV plane that are larger by
10%, with already fast objects gaining more. Using the new data, while applying
the same UV-velocity cut (94 km/s) as in OHDHS, we find a density of cool WDs
of 1.7e-4 pc^-3, confirming the value of OHDHS. In addition, we derive the
density as a function of the UV-velocity cutoff. The density (corrected for
losses due to higher UV cuts) starts to flatten out at 150 km/s (0.4e-4 pc^-3),
and is minimized (thus minimizing a possible non-halo contamination) at 190
km/s (0.3e-4 pc^-3). These densities are in a rough agreement with the
estimates for the stellar halo WDs, corresponding to a factor of 1.9 and 1.4
higher values.Comment: Accepted to ApJ. New version contains some additional data. Results
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