382 research outputs found
BMP signals: Mediated by stroma or thymocytes?
This is an invited comment on the paper by Hager-Theodorides AL, et al. Cell Cycle 2014; 13:324–33; PMID:24240189; http://dx.doi.org/10.4161/cc.27118 which is published in the same journa
The feasability of inertial measurement units (IMU) in capturing basic upper body motion
INTRODUCTION
Three- Dimensional (3D) motion capture is accepted
to be the gold standard approach to all data collection
for the production of accurate data. Yet concerns over
the ecological validity of 3D systems has come into
question [1]. This has brought about the exploration
of alternate methods such as inertial measurement
units (IMU’s). The depth of research on IMU usage in
wheelchair data collection is limited, particularly in
comparison to an established data collection system,
primarily focused around the use of IMU’s rather than
validation studies aiming to ensure their reliability and
accuracy. This single-subject pilot study aims to
explore the feasibility of using IMU’s for capturing
basic upper body motions during wheelchair
propulsion. Specifically, to assess the potential
limitations of IMUs in accurately measuring elbow
and shoulder flexion.
METHODS
Several IMU (Vicon Blue Trident sensor, Vicon,
Oxford, UK) placements and calibration stances were
investigated for the collection of elbow flexion and
shoulder flexion. The IMUs utilized were Vicon Blue
Trident sensors (Vicon, Oxford, UK). IMUs were
positioned at two locations for elbow flexion: at the
wrist and centrally on the forearm. For shoulder
flexion measurements, the IMU was situated 1 cm
above the elbow joint. During the calibration phase,
the participant assumed a standing anatomical
position with their thumbs forwards, palms outwards,
bent elbow and straight arms outwards at 90 degrees
for elbow flexion and shoulder flexion respectfully.
For both shoulder and elbow flexion, the participant
started at a neutral position and proceeded to move
through to 90 degrees of flexion and returned to
starting position. Quintic biomechanical software
(Quintic Biomechanics v25 Video Analysis Software,
Quintic Consultancy, West Midlands, UK) was
employed as the validated reference system for data
comparison and analysis.
RESULTS & DISCUSSION
The wrist placed IMU determined elbow flexion more
accurately than the forearm placed IMU. Range of
motion for both shoulder and elbow flexion were well
calculated within several degrees when using the
anatomical thumbs forwards calibration pose; with
100.0 and 89.7° respectively compared to 88.5 and
97.3°. However, the degree of elbow flexion in
relation to maximum values was overestimated with a
difference of 27.8°, with the IMU being 91.1 degrees
and quintic being 63.3°. Similar was also seen for the
prediction of elbow flexion during the starting stance
phase with a difference of 26.6 degrees. Shoulder
flexion prediction was better calculated with a smaller
difference of 6,6° between the IMU and Quintic for
the thumbs forward calibration pose and 2.5 degrees
for the palms forward calibration pose. For both
shoulder and elbow flexion, the arms forward
calibration stance resulted in large differences, with
14.6° and 75.1° difference in range of motion seen
respectively.
CONCLUSION
With range of motion accurately calculated in
comparison to quintic, and shoulder flexion maximum
and minimum values also being similar when
segment angle was calculated. Then the differences
are likely due to error in the calculation of joint angle
using a calculation of global coordinate system from
the IMU coordinate system during data processing.
Therefore, future research should target alternate
approaches to data processing in order to reduce the
errors seen. However, the accuracy in range of
motion prediction, presents the scope for further
research into the use of IMU’s in elements such as
bilateral differences in range of motion during
wheelchair activities. This potentially allows for their
use in basic analysis of wheelchair propulsion and
gives scope for investigation into factors such as
ground type on basic upper body motion during
wheelchair propulsion
Probing 3-D matter distribution at z~2 with QSO multiple lines of sight
We investigate the 3-D matter distribution at z~2 with high resolution (R ~
40000) spectra of QSO pairs and groups obtained with the UVES spectrograph at
ESO VLT. Our sample is unique for the number density of objects and the variety
of separations, between 0.5 and 7 proper Mpc. We compute the real space
cross-correlation function of the Lyman-alpha forest transmitted fluxes. There
is a significant clustering signal up to ~2 proper Mpc, which is still present
when absorption lines with high column density (log N > 13.8) are excluded.Comment: Poster paper presented at the IAU Colloquium #199 on "Probing
Galaxies through Quasar Absorption Lines" held in Shanghai, China from March
14th to 18th, 200
Tomography of the intergalactic medium with Ly-alpha forests in close QSO pairs
We study the three-dimensional distribution of non virialised matter at z~2
using high resolution spectra of QSO pairs and simulated spectra drawn from
cosmological hydrodynamical simulations. We have collected the largest sample
of QSO pairs ever observed with UVES at the ESO-VLT, with angular separations
between ~1 and 14 arcmin. The observed correlation functions of the transmitted
flux in the HI Lyman alpha forest along and transverse to the lines of sight
are in good agreement implying that the distortions in redshift space due to
peculiar velocities are small. The clustering signal is significant up to
velocity separations of ~200 km/s, or about 3 h^{-1} comoving Mpc. The regions
at lower overdensity (rho/ < 6.5) are still clustered but on smaller
scales (Delta v < 100 km/s). The observed and simulated correlation functions
are compatible at the 3 sigma level. A better concordance is obtained when only
the low overdensity regions are selected for the analysis or when the effective
optical depth of the simulated spectra is increased artificially, suggesting a
deficiency of strong lines in the simulated spectra. We found that also a lower
value of the power-law index of the temperature-density relation for the Lyman
alpha forest gas improves the agreement between observed and simulated results.
If confirmed, this would be consistent with other observations favouring a late
HeII reionization epoch (at z~3). We remark the detection of a significant
clustering signal in the cross correlation coefficient at a transverse velocity
separation Delta v_{\perp} ~500 km/s whose origin needs further investigation.Comment: Accepted for publication in MNRAS, revised version matching the
accepted on
Recommendations from recent graduates in medicine, nursing and pharmacy on improving interprofessional education in university programs: A qualitative study
Background: Interprofessional education (IPE) has been recognized as an innovative approach for the development of a collaborative, practice-ready health workforce, but is not used consistently in undergraduate health professional programs. We sought to explore the reflections of graduates on the IPE experiences they had during their undergraduate education and training. It was anticipated that having completed their pre-vocational education and spent up to two years working in a clinical environment, recent graduates would be well-placed to provide insights into the value of the IPE opportunities they had, and to suggest approaches for improving these opportunities in undergraduate programs. Methods. This study was part of a larger research project (Interprofessional Education for the Quality use of Medicines; IPE for QuM) which used focus groups as part of an interpretive research design to inform other aspects of the research. Here, we report on focus groups with recent graduates recruited from area health services across Australia. Results: Sixty-eight recent graduates working in New South Wales, Western Australia, and Tasmania participated in 12 focus group sessions. In this paper, we report on new graduates' reflections on their experiences of IPE as part of their university degree, as well as their recommendations to improve interprofessional education before graduation. The new graduates were unanimous in valuing IPE from their current perspective of being in the health workforce. Most IPE experiences recalled were regarded as positive, but those valued most highly were experiences that involved genuine engagement and opportunities to interact with students in other professions working on a relevant problem. Clinical placement was a missed opportunity with few structured meaningful interprofessional learning experiences. Surprisingly there was little social contact between professions in universities even when programs were co-located, thus reinforcing professional silos. Conclusions: The graduates provided many insightful reflections about the value of university-based IPE and their preparedness for clinical practice. Although universally acclaimed as a good idea there is much room for improvement. We put forward a set of suggestions to improve IPE and guide the design of future IPE efforts. © 2014 Gilligan et al.; licensee BioMed Central Ltd
Clustering in the 2dF QSO Redshift Survey
We present clustering results from the 2dF QSO Redshift Survey (2QZ) which
currently contains over 20,000 QSOs at z<3. The two-point correlation function
of QSOs averaged over the entire survey (~1.5) is found to be similar to
that of local galaxies. When sub-dividing the sample as a function of redshift,
we find that for an Einstein-de Sitter universe QSO clustering is constant (in
comoving coordinates) over the entire redshift range probed by the 2QZ, while
in a universe with Omega_0=0.3 and Lambda_0=0.7 there is a marginal increase in
clustering with redshift. Sub-dividing the 2QZ on the basis of apparent
magnitude we find only a slight difference between the clustering of QSOs of
different apparent brightness, with the brightest QSOs having marginally
stronger clustering. We have made a first measurement of the redshift space
distortion of QSO clustering, with the goal of determining the value of
cosmological parameters (in partcular Lambda_0) from geometric distortions. The
current data do not allow us to discriminate between models, however, in
combination with constraints from the evolution of mass clustering we find
Omega_0=1-Lambda_0=0.23 +0.44-0.13 and beta(z~1.4)=0.39 +0.18-0.17. The full
2QZ data set will provide further cosmological constraints.Comment: 5 pages, 7 figures. Contributed to the 'Where's the Matter'
conference in Marseille 25-29 June 200
First Results from the 2dF QSO redshift survey
We present some initial results from the 2dF QSO redshift survey. The aim of
the survey is to produce an optically-selected catalogue of 25000 QSOs over the
redshift range 0<z<3 using the 2-degree field at the Anglo-Australian
Telescope.Comment: 7 pages, 6 figures, submitted to proceedings of ESO Deep Fields
conferenc
The 2dF QSO Redshift Survey - 10K@2K!
With ~10000 QSO redshifts, the 2dF QSO Redshift Survey (2QZ) is already the
biggest individual QSO survey. The aim for the survey is to have ~25000 QSO
redshifts, providing an order of magnitude increase in QSO clustering
statistics. We first describe the observational parameters of the 2dF QSO
survey. We then describe several highlights of the survey so far; we present
new estimates of the QSO luminosity function and the QSO correlation function.
We also present the first estimate of the QSO power spectrum from the 2QZ
catalogue, probing the form of the fluctuation power-spectrum out to the
\~1000h-1Mpc scales only previously probed by COBE. We find a power spectrum
which is steeper than the prediction of standard CDM and more consistent with
the prediction of Lambda-CDM. The best-fit value for the power spectrum shape
parameter for a range of cosmologies is Gamma=0.1+-0.1. Finally, we discuss how
the complete QSO survey will be able to constrain the value of Omega_Lambda by
combining results from the evolution of QSO clustering and from a geometric
test of clustering isotropy.Comment: 11 pages, 6 figures, latex, eso and springer sty files included. To
appear in the proceedings of the MPA/ESO/MPA conference "Mining the Sky",
Garching, July 31 - August 4 2000, eds. A.J. Banday et a
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