3,179 research outputs found
The effect of military load carriage on ground reaction forces
Load carriage is an inevitable part of military life both during training and operations. Loads carried are frequently as high as 60% bodyweight, and this increases injury risk. In the military, load is carried in a backpack (also referred to as a Bergen) and webbing, these combined form a load carriage system (LCS). A substantial body of literature exists recording the physiological effects of load carriage; less is available regarding the biomechanics. Previous biomechanical studies have generally been restricted to loads of 20% and 40% of bodyweight, usually carried in the backpack alone. The effect of rifle carriage on gait has also received little or no attention in the published literature. This is despite military personnel almost always carrying a rifle during load carriage. In this study, 15 male participants completed 8 conditions: military boot, rifle, webbing 8 and 16 kg, backpack 16 kg and LCS 24, 32 and 40 kg. Results showed that load added in 8 kg increments elicited a proportional increase in vertical and anteroposterior ground reaction force (GRF) parameters. Rifle carriage significantly increased the impact peak and mediolateral impulse compared to the boot condition. These effects may be the result of changes to the vertical and horizontal position of the body's centre of mass, caused by the restriction of natural arm swing patterns. Increased GRFs, particularly in the vertical axis, have been positively linked to overuse injuries. Therefore, the biomechanical analysis of load carriage is important in aiding our understanding of injuries associated with military load carriage
Microwave ISM Emission in the Green Bank Galactic Plane Survey: Evidence for Spinning Dust
We observe significant dust-correlated emission outside of H II regions in
the Green Bank Galactic Plane Survey (-4 < b < 4 degrees) at 8.35 and 14.35
GHz. The rising spectral slope rules out synchrotron and free-free emission as
majority constituents at 14 GHz, and the amplitude is at least 500 times higher
than expected thermal dust emission. When combined with the Rhodes (2.326 GHz),
and WMAP (23-94 GHz) data it is possible to fit dust-correlated emission at
2.3-94 GHz with only soft synchrotron, free-free, thermal dust, and an
additional dust-correlated component similar to Draine & Lazarian spinning
dust. The rising component generally dominates free-free and synchrotron for
\nu >~ 14 GHz and is overwhelmed by thermal dust at \nu > 60 GHz. The current
data fulfill most of the criteria laid out by Finkbeiner et al. (2002) for
detection of spinning dust.Comment: ApJ in press. 26 pages, 11 figures, figures jpeg compressed to save
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Do we want a fighter? The influence of group status and the stability of intergroup relations on leader prototypicality and endorsement
Based on the idea that leadership is a group process, we propose that followers' endorsement of a leader depends on particular leadership strategies being perceived to be best suited for maintaining or advancing group identity in the context of prevailing intergroup relations. Three experimental studies with different samples aimed to examine how socio-structural variables that define intergroup relations impact on leaderâfollower relations and on the support that followers give to leaders who adopt different approaches to manage intergroup relations. We demonstrate that after manipulating the status and the stability of intergroup relations followers endorse leaders who strategically engage in group-oriented behaviour that maps onto optimal identity-management strategies. These patterns mirrored differences across contexts in the perceived prototypicality. We conclude that intergroup relations influence leaders' strategic behaviour and followers' reaction to them. Findings highlight the importance of understanding leadership as both a within- and between-group process
Audit committees, non-audit services, and auditor reporting decisions prior to failure
This study investigates the associations between audit committee characteristics and the likelihood of auditors' going-concern decisions among UK failed firms. Specifically, we examine whether the threat posed by auditor-provided non-audit services (NAS) to auditors' reporting decisions is mediated by audit committee characteristics. We find that failed firms with higher proportions of independent non-executive directors (NEDs) and financial experts on the audit committee are more likely to receive auditor going-concern modifications prior to failure, but that there is no significant relationship between NAS fees and the likelihood of receiving a going-concern modification. The evidence further suggests that the association between NAS and auditors' reporting decisions is subject to audit committee characteristics. Where the audit committee is more independent and includes a greater proportion of financial experts, auditors providing the client with NAS are less likely to issue a standard unmodified going-concern report prior to failure. Overall, the findings provide support for corporate governance regulators' concerns about the monitoring benefits of audit committee independence and the presence of financial expertise on the audit committee for auditors' reporting decisions
A physical property model of the Chalk of Southern England
This report describes the rationale and procedure for the construction of a new high-resolution
stratigraphical and physical property model of the Chalk Group of southern England. The model
integrates bedrock mapping data for the Chalk, with structural data and interpretations of
formational and sub-formational (marker-bed) stratigraphy in boreholes (predominantly from
geophysical logs and cored boreholes) and outcrops. A range of simple facies data (e.g. hard
chalk, hardground, marl, marly chalk) are coded for the boreholes and outcrops using WellCadTM
software, interpreted directly from geophysical logs, core logs, borehole video logs, or outcrop
logs. The results of this work are modelled in SKUA-GOCAD 2013.2 software, using statistical
algorithms to project the likely distribution of physical property data
Joint Bayesian component separation and CMB power spectrum estimation
We describe and implement an exact, flexible, and computationally efficient
algorithm for joint component separation and CMB power spectrum estimation,
building on a Gibbs sampling framework. Two essential new features are 1)
conditional sampling of foreground spectral parameters, and 2) joint sampling
of all amplitude-type degrees of freedom (e.g., CMB, foreground pixel
amplitudes, and global template amplitudes) given spectral parameters. Given a
parametric model of the foreground signals, we estimate efficiently and
accurately the exact joint foreground-CMB posterior distribution, and therefore
all marginal distributions such as the CMB power spectrum or foreground
spectral index posteriors. The main limitation of the current implementation is
the requirement of identical beam responses at all frequencies, which restricts
the analysis to the lowest resolution of a given experiment. We outline a
future generalization to multi-resolution observations. To verify the method,
we analyse simple models and compare the results to analytical predictions. We
then analyze a realistic simulation with properties similar to the 3-yr WMAP
data, downgraded to a common resolution of 3 degree FWHM. The results from the
actual 3-yr WMAP temperature analysis are presented in a companion Letter.Comment: 23 pages, 16 figures; version accepted for publication in ApJ -- only
minor changes, all clarifications. More information about the WMAP3 analysis
available at http://www.astro.uio.no/~hke under the Research ta
A Search for Sub-Millisecond Pulsars
We have conducted a search of 19 southern Galactic globular clusters for
sub-millisecond pulsars at 660 MHz with the Parkes 64-m radio telescope. To
minimize dispersion smearing we used the CPSR baseband recorder, which samples
the 20 MHz observing band at the Nyquist rate. By possessing a complete
description of the signal we could synthesize an optimal filterbank in
software, and in the case of globular clusters of known dispersion measure,
much of the dispersion could be removed using coherent techniques. This allowed
for very high time resolution (25.6 us in most cases), making our searches in
general sensitive to sub-millisecond pulsars with flux densities greater than
about 3 mJy at 50 cm. No new pulsars were discovered, placing important
constraints on the proportion of pulsars with very short spin periods in these
clusters.Comment: 8 pages, 3 figures, to appear in Ap
Effects of Foreground Contamination on the Cosmic Microwave Background Anisotropy Measured by MAP
We study the effects of diffuse Galactic, far-infrared extragalactic source,
and radio point source emission on the cosmic microwave background (CMB)
anisotropy data anticipated from the MAP experiment. We focus on the
correlation function and genus statistics measured from mock MAP
foreground-contaminated CMB anisotropy maps generated in a spatially-flat
cosmological constant dominated cosmological model. Analyses of the simulated
MAP data at 90 GHz (0.3 deg FWHM resolution smoothed) show that foreground
effects on the correlation function are small compared with cosmic variance.
However, the Galactic emission, even just from the region with |b| > 20 deg,
significantly affects the topology of CMB anisotropy, causing a negative genus
shift non-Gaussianity signal. Given the expected level of cosmic variance, this
effect can be effectively reduced by subtracting existing Galactic foreground
emission models from the observed data. IRAS and DIRBE far-infrared
extragalactic sources have little effect on the CMB anisotropy. Radio point
sources raise the amplitude of the correlation function considerably on scales
below 0.5 deg. Removal of bright radio sources above a 5 \sigma detection limit
effectively eliminates this effect. Radio sources also result in a positive
genus curve asymmetry (significant at 2 \sigma) on 0.5 deg scales. Accurate
radio point source data is essential for an unambiguous detection of CMB
anisotropy non-Gaussianity on these scales. Non-Gaussianity of cosmological
origin can be detected from the foreground-subtracted CMB anisotropy map at the
2 \sigma level if the measured genus shift parameter |\Delta\nu| >= 0.02 (0.04)
or if the measured genus asymmetry parameter |\Delta g| >= 0.03 (0.08) on a 0.3
(1.0) deg FWHM scale.Comment: 26 pages, 7 figures, Accepted for Publication in Astrophysical
Journal (Some sentences and figures modified
Galactic microwave emission at degree angular scales
We cross-correlate the Saskatoon Ka and Q-Band Cosmic Microwave Background
(CMB) data with different maps to quantify possible foreground contamination.
We detect a marginal correlation (2 sigma) with the Diffuse Infrared Background
Experiment (DIRBE) 240, 140 and 100 microm maps, but we find no significant
correlation with point sources, with the Haslam 408 MHz map or with the Reich
and Reich 1420 MHz map. The rms amplitude of the component correlated with
DIRBE is about 20% of the CMB signal. Interpreting this component as free-free
emission, this normalization agrees with that of Kogut et al. (1996a; 1996b)
and supports the hypothesis that the spatial correlation between dust and warm
ionized gas observed on large angular scales persists to smaller angular
scales. Subtracting this contribution from the CMB data reduces the
normalization of the Saskatoon power spectrum by only a few percent.Comment: Minor revisions to match published version. 14 pages, with 2 figures
included. Color figure and links at
http://www.sns.ias.edu/~angelica/foreground.htm
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