6,826 research outputs found
Perceived importance of components of asynchronous music in circuit training
This study examined regular exercisers’ perceptions of specific components of music
during circuit training. Twenty-four men (38.8 years, s = 11.8 years) and 31 women
(32.4 years, s = 9.6 years) completed two questionnaires immediately after a circuit
training class. Participants rated the importance of 13 components of music (rhythm,
melody, etc.) in relation to exercise enjoyment, and each completed the Affect Intensity
Measure (Larsen, 1984) to measure emotional reactivity. Independent t tests were used
to evaluate gender differences in perceptions of musical importance. Pearson
correlations were computed to evaluate the relationships between affect intensity, age
and importance of musical components. Consistent with previous research and
theoretical predictions, rhythm response components (rhythm, tempo, beat) were rated
as most important. Women rated the importance of melody significantly higher than did
men, while men gave more importance to music associated with sport. Affect intensity
was found to be positively and significantly related to the perceived importance of
melody, lyrical content, musical style, personal associations and emotional content.
Results suggest that exercise leaders need to be sensitive to personal factors when
choosing music to accompany exercise. Qualitative research that focuses on the
personal meaning of music is encouraged
A comparison of four different imaging modalities - conventional, cross polarized, infra-red and ultra-violet in the assessment of childhood bruising
Background
It is standard practice to image concerning bruises in children. We aim to compare the clarity and measurements of bruises using cross polarized, infra-red (IR) and ultra-violet (UV) images to conventional images.
Methods
Children aged <11 years with incidental bruising were recruited. Demographics, skin and bruise details were recorded. Bruises were imaged by standard protocols in conventional, cross-polarized, IR and UV lights. Bruises were assessed in vivo for contrast, uniformity and diffuseness, and these characteristics were then compared across image modalities. Color images (conventional, cross polarized) were segmented and measured by ImageJ. Bruises of grey scale images (IR, UV) were measured by a ‘plug in’ of ImageJ. The maximum and minimum Feret's diameter, area and aspect ratio, were determined. Comparison of measurements across imaging modalities was conducted using Wilcoxon rank sum tests and modified Bland-Altman graphs. Significance was set at p < 0.05.
Results
Twenty five children had 39 bruises. Bruises that were of low contrast, i.e. difficult to distinguish from surrounding skin, were also more diffuse, and less uniformity in vivo. Low contrast bruises were best seen on conventional and cross-polarized images and less distinctive on IR and UV images. Of the 19 bruises visible in all modalities, the only significant difference was maximum and minimum Feret's diameters and area were smaller on IR compared to conventional images. Aspect ratios were not affected by the modality.
Conclusions
Conventional and cross-polarized imaging provides the most consistent bruise measurement, particularly in bruises that are not easily distinguished from surrounding skin visually
Two Galaxy Clusters: A3565 and A3560
We report 102 new redshifts and magnitudes for a sample of galaxies to RF ~
15.5 mag in a 2.17 deg x 2.17 deg region centered on the galaxy IC 4296, the
most luminous member of the A3565 cluster. Up to the limiting magnitude we find
29 cluster members, and measure a velocity dispersion of 228 km/s. The
estimated total mass for this system is ~ 3.0 x h**-1 10**13 Msun (where h =
H0/100 km/s/Mpc), and its dynamical properties are quite typical of poor
clusters presenting X-ray emission. We also find that galaxies with absorption
lines are more concentrated towards the center of the cluster, while systems
with emission lines are mainly located in the outer parts. The small velocity
dispersion of the cluster, coupled to the known presence of an interacting pair
of galaxies, and the large extent of the brightest cluster galaxy, could
indicate that galaxy formation through mergers may still be underway in this
system. The surveyed region also contains galaxies belonging to the Shapley
Concentration cluster A3560. Within 30 arc min of the cluster center, we detect
32 galaxies, for which we measure a velocity dispersion of 588 km/s and a mass
of ~2 x h**-1 10**14 Msun. However, because our sample is restricted to
galaxies brighter than M*, these values should be considered only as rough
estimates.Comment: 33 pages, including 6 tables and 9 postscript figures. Uses AAS Latex
macros. Postscript file and ASCII versions of Tables 4 and 6 are available at
http://www.dan.on.br/other_surveys/a3565.html. Scheduled for September 1999
issue of The Astronomical Journa
Fast-ignition design transport studies: realistic electron source, integrated PIC-hydrodynamics, imposed magnetic fields
Transport modeling of idealized, cone-guided fast ignition targets indicates
the severe challenge posed by fast-electron source divergence. The hybrid
particle-in-cell [PIC] code Zuma is run in tandem with the
radiation-hydrodynamics code Hydra to model fast-electron propagation, fuel
heating, and thermonuclear burn. The fast electron source is based on a 3D
explicit-PIC laser-plasma simulation with the PSC code. This shows a quasi
two-temperature energy spectrum, and a divergent angle spectrum (average
velocity-space polar angle of 52 degrees). Transport simulations with the
PIC-based divergence do not ignite for > 1 MJ of fast-electron energy, for a
modest 70 micron standoff distance from fast-electron injection to the dense
fuel. However, artificially collimating the source gives an ignition energy of
132 kJ. To mitigate the divergence, we consider imposed axial magnetic fields.
Uniform fields ~50 MG are sufficient to recover the artificially collimated
ignition energy. Experiments at the Omega laser facility have generated fields
of this magnitude by imploding a capsule in seed fields of 50-100 kG. Such
imploded fields are however more compressed in the transport region than in the
laser absorption region. When fast electrons encounter increasing field
strength, magnetic mirroring can reflect a substantial fraction of them and
reduce coupling to the fuel. A hollow magnetic pipe, which peaks at a finite
radius, is presented as one field configuration which circumvents mirroring.Comment: 16 pages, 17 figures, submitted to Phys. Plasma
High Floral Tannin White Clover Reduces Rumen Ammonia Concentrations in Dairy Cows
White clover produces high quality forage for ruminant production, but it results in high rumen ammonia concentrations, indicating extensive protein degradation. The excess ammonia is absorbed through the rumen and excreted as urea in urine, at a cost to the animal and the environment. Condensed tannins (CT) contained in some forages reduce proteolysis in the rumen, which can lead to increased amino acid absorption and therefore improved animal performance. White clover produces CT in its flower heads, but concentrations are normally too low to benefit animals. This paper reports on comparisons of rumen ammonia concentrations in dairy cows grazing HT (high tannin) white clover (an experimental line of white clover with increased flowering) or Grasslands Huia white clover
Condensed Tannin Concentration and Herbage Accumulation of a White Clover Bred for Increased Floral Condensed Tannin
White clover is a high quality feed for ruminants, however, its high protein content results in excessive urea excretion in urine and can cause bloat, reducing its potential value for animal production. The condensed tannins (CT) in some forages can reduce these problems, but plants may have poor agronomic performance. White clover produces CT in its flower heads, but herbage CT concentrations are normally too low to benefit animals. This paper reports CT concentrations and herbage accumulation over 2 years of an experimental line of white clover (HT) selected for increased flowering and floral CT concentrations
GRB 021004: A Possible Shell Nebula around a Wolf-Rayet Star Gamma-Ray Burst Progenitor
The rapid localization of GRB 021004 by the HETE-2 satellite allowed nearly
continuous monitoring of its early optical afterglow decay, as well as
high-quality optical spectra that determined a redshift of z3=2.328 for its
host galaxy, an active starburst galaxy with strong Lyman-alpha emission and
several absorption lines. Spectral observations show multiple absorbers at
z3A=2.323, z3B= 2.317, and z3C= 2.293 blueshifted by 450, 990, and 3,155 km/s
respectively relative to the host galaxy Lyman-alpha emission. We argue that
these correspond to a fragmented shell nebula that has been radiatively
accelerated by the gamma-ray burst (GRB) afterglow at a distance greater than
0.3 pc from a Wolf-Rayet star progenitor. The chemical abundance ratios
indicate that the nebula is overabundant in carbon and silicon. The high level
of carbon and silicon is consistent with a swept-up shell nebula gradually
enriched by a WCL progenitor wind over the lifetime of the nebula prior to the
GRB onset. The detection of statistically significant fluctuations and color
changes about the jet-like optical decay further supports this interpretation
since fluctuations must be present at some level due to inhomogeneities in a
clumpy stellar wind medium or if the progenitor has undergone massive ejection
prior to the GRB onset. This evidence suggests that the mass-loss process in a
Wolf-Rayet star might lead naturally to an iron-core collapse with sufficient
angular momentum that could serve as a suitable GRB progenitor.Comment: Replaced with version accepted by ApJ; 40 pages, 9 figure
Mating Ewes on Condensed Tannin-Containing Forages Increases Ewe Reproductive Rate and Reduces Lamb Mortality
Action of condensed tannin (CT) reduces forage protein degradation in the rumen and increases the absorption of amino acids from the small intestine (Barry & McNabb 1999). This paper reports the effects of grazing ewes on two CT-containing forages during mating upon ewe reproductive rate and lamb mortality
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