3,996 research outputs found
Experimental X-ray Stress Analysis Procedures for Ultra High Strength Materials
X-ray stress analysis procedures for accurate measurement of elastic strain in high strength steel
Environmental monitoring of Mycobacterium bovis in badger feces and badger sett soil by real-time PCR, as confirmed by immunofluorescence, immunocapture, and cultivation
Real-time PCR was used to detect and quantify Mycobacterium bovis cells in
naturally infected soil and badger faeces. Immunomagnetic capture,
immunofluorescence and selective culture confirmed species identification and cell
viability. These techniques will prove useful for monitoring M. bovis in the
environment and for elucidating transmission routes between wildlife and cattle
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
Properties of extragalactic dust inferred from linear polarimetry of Type Ia Supernovae
Aims: The aim of this paper is twofold: 1) to investigate the properties of
extragalactic dust and compare them to what is seen in the Galaxy; 2) to
address in an independent way the problem of the anomalous extinction curves
reported for reddened Type Ia Supernovae (SN) in connection to the environments
in which they explode. Methods: The properties of the dust are derived from the
wavelength dependence of the continuum polarization observed in four reddened
Type Ia SN: 1986G, 2006X, 2008fp, and 2014J. [...] Results: All four objects
are characterized by exceptionally low total-to-selective absorption ratios
(R_V) and display an anomalous interstellar polarization law, characterized by
very blue polarization peaks. In all cases the polarization position angle is
well aligned with the local spiral structure. While SN~1986G is compatible with
the most extreme cases of interstellar polarization known in the Galaxy,
SN2006X, 2008fp, and 2014J show unprecedented behaviours. The observed
deviations do not appear to be connected to selection effects related to the
relatively large amounts of reddening characterizing the objects in the sample.
Conclusions: The dust responsible for the polarization of these four SN is most
likely of interstellar nature. The polarization properties can be interpreted
in terms of a significantly enhanced abundance of small grains. The anomalous
behaviour is apparently associated with the properties of the galactic
environment in which the SN explode, rather than with the progenitor system
from which they originate. For the extreme case of SN2014J, we cannot exclude
the contribution of light scattered by local material; however, the observed
polarization properties require an ad hoc geometrical dust distribution.Comment: 10 pages, 6 figures, accepted for publication in Astronomy and
Astrophysic
Performance of an environmental test to detect Mycobacterium bovis infection in badger social groups
A study by Courtenay and others (2006) demonstrated that
the probability of detecting Mycobacterium bovis by PCR in
soil samples from the spoil heaps of main badger setts correlated
with the prevalence of excretion (infectiousness) of
captured badgers belonging to the social group. It has been
proposed that such a test could be used to target badger culling
to setts containing infectious animals (Anon 2007). This
short communication discusses the issues surrounding this
concept, with the intention of dispelling any misconceptions
among relevant stakeholders (farmers, policy makers and
conservationists)
Continuum Foreground Polarization and Na i Absorption in Type Ia SNe
We present a study of the continuum polarization over the 400-600 nm range of 19 SNe Ia obtained with FORS at the VLT. We separate them into those that show Na i D lines at the velocity of their hosts and those that do not. Continuum polarization of the sodium sample near maximum light displays a broad range of values, from extremely polarized cases like SN 2006X to almost unpolarized ones like SN 2011ae. The non-sodium sample shows, typically, smaller polarization values. The continuum polarization of the sodium sample in the 400-600 nm range is linear with wavelength and can be characterized by the mean polarization (Pmean). Its values span a wide range and show a linear correlation with color, color excess, and extinction in the visual band. Larger dispersion correlations were found with the equivalent width of the Na i D and Ca ii H and K lines, and also a noisy relation between Pmean and RV, the ratio of total to selective extinction. Redder SNe show stronger continuum polarization, with larger color excesses and extinctions. We also confirm that high continuum polarization is associated with small values of RV. The correlation between extinction and polarization - and polarization angles - suggest that the dominant fraction of dust polarization is imprinted in interstellar regions of the host galaxies. We show that Na i D lines from foreground matter in the SN host are usually associated with non-galactic ISM, challenging the typical assumptions in foreground interstellar polarization models
Intraoperative manufacturing of patient specific instrumentation for shoulder arthroplasty: a novel mechatronic approach
Optimal orthopaedic implant placement is a major contributing factor to the long term success of all common joint arthroplasty procedures. Devices such as three-dimensional (3D) printed, bespoke guides and orthopaedic robots are extensively described in the literature and have been shown to enhance prosthesis placement accuracy. These technologies, however, have significant drawbacks, such as logistical and temporal inefficiency, high cost, cumbersome nature and difficult theatre integration. A new technology for the rapid intraoperative production of patient specific instrumentation, which overcomes many of the disadvantages of existing technologies, is presented here. The technology comprises a reusable table side machine, bespoke software and a disposable element comprising a region of standard geometry and a body of mouldable material. Anatomical data from Computed Tomography (CT) scans of 10 human scapulae was collected and, in each case, the optimal glenoid guidewire position was digitally planned and recorded. The achieved accuracy compared to the preoperative bespoke plan was measured in all glenoids, from both a conventional group and a guided group. The technology was successfully able to intraoperatively produce sterile, patient specific guides according to a pre-operative plan in 5 minutes, with no additional manufacturing required prior to surgery. Additionally, the average guide wire placement accuracy was 1.58 mm and 6.82â—¦ degrees in the manual group, and 0.55 mm and 1.76â—¦ degrees in the guided group, also demonstrating a statistically significant improvement
Extreme sensitivity of the spin-splitting and 0.7 anomaly to confining potential in one-dimensional nanoelectronic devices
Quantum point contacts (QPCs) have shown promise as nanoscale spin-selective
components for spintronic applications and are of fundamental interest in the
study of electron many-body effects such as the 0.7 x 2e^2/h anomaly. We report
on the dependence of the 1D Lande g-factor g* and 0.7 anomaly on electron
density and confinement in QPCs with two different top-gate architectures. We
obtain g* values up to 2.8 for the lowest 1D subband, significantly exceeding
previous in-plane g-factor values in AlGaAs/GaAs QPCs, and approaching that in
InGaAs/InP QPCs. We show that g* is highly sensitive to confinement potential,
particularly for the lowest 1D subband. This suggests careful management of the
QPC's confinement potential may enable the high g* desirable for spintronic
applications without resorting to narrow-gap materials such as InAs or InSb.
The 0.7 anomaly and zero-bias peak are also highly sensitive to confining
potential, explaining the conflicting density dependencies of the 0.7 anomaly
in the literature.Comment: 23 pages, 7 figure
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