1,575 research outputs found
An Extinction Threshold for Protostellar Cores in Ophiuchus
We have observed continuum emission at lambda = 850 microns over ~4 square
degrees of the Ophiuchus star-forming cloud using SCUBA on the JCMT, producing
a submillimetre continuum map twenty times larger than previous Ophiuchus
surveys. Our sensitivity is 40 mJ/beam, a factor of ~2 less sensitive than
earlier maps. Using an automated identification algorithm, we detect 100
candidate objects. Only two new objects are detected outside the boundary of
previous maps, despite the much wider area surveyed. We compare the
submillimetre continuum map with a map of visual extinction across the
Ophiuchus cloud derived using a combination of 2MASS and R-band data. The total
mass in submillimetre objects is ~ 50 Msun compared with ~ 2000 Msun in
observed cloud mass estimated from the extinction. The submillimetre objects
represent only 2.5% of the cloud mass. A clear association is seen between the
locations of detected submillimetre objects and high visual extinction, with no
objects detected at A_V<7 magnitudes. Using the extinction map, we estimate
pressures within the cloud from P/k ~2x10^5 cm^-3 K in the less-extincted
regions to P/k ~2x10^6 cm^-3 K at the cloud centre. Given our sensitivities,
cold (T_d ~15K) clumps supported by thermal pressure, had they existed, should
have been detected throughout the majority of the map. Such objects may not be
present at low A_V because they may form only where A_V > 15, by some mechanism
(e.g., loss of non-thermal support).Comment: 12 pages, 1 figure. Accepted by Astrophysical Journal Letter
The Measurement of Sporting Performance using Mobile Physiological Monitoring Technology
Coaches are constantly seeking more ecologically valid and reliable data to improve professional sporting performance. Using unobtrusive, valid and reliable mobile physiological monitoring devices may assist in achieving this aim. For example, there is limited information regarding professional fast bowlers in cricket and understanding this role during competitive in-match scenarios rather than in simulated bowling events could enhance coaching and physical conditioning practices. The BioharnessTM is a mobile monitoring device and assesses 5 variables (Heart rate [HR], Breathing frequency [BF], Accelerometry [ACC], Skin temperature [ST] and Posture [P]) simultaneously. Therefore, the aims of this research were to assess the effectiveness of the BioharnessTM mobile monitoring device during professional sporting performance using fast bowlers in cricket and this was to be achieved in five research studies. Study 1 presented the physiological profile of professional cricketers reporting fitness data with other comparable professional athletes, with a specific interest in fast bowlers who were to be the focus of this work. The 2nd and 3rd study assessed the reliability and validity of the BioharnessTM through controlled laboratory based assessment. For validity, strong relationships (r = .89 to .99, P .89, P 79.2 beat.min-1) and BF (> 54.7 br.min-1). ACC presented excellent precision (r = .94, P .97, P 10 km.h-1) variables became more erroneous. HR and ACC were deemed as valid and reliable to be assessed during in-match sporting performance in study 5. This final study sought to utilise and assess the BioharnessTM device within professional cricket, assessing physiological responses of fast-medium bowlers within a competitive sporting environment, collected over three summer seasons. The BioharnessTM presented different physiological profiles for One Day (OD) and Multi Day (MD) cricket with higher mean HR (142 vs 137 beats.min-1, P < .05) and ACC (Peak acceleration (PkA) 227.6 vs 214.9 ct.episode-1, P < .01) values in the shorter match format. Differences in data for the varying match states of bowling (HR, 142 vs 137 beats.min-1, PkA 234.1 vs 226.6 ct.episode-1), between over (HR, 129 vs 120beats.min-1, PkA 136.4 vs 126.5 ct.episode-1) and fielding (115 vs 106 beats.min-1, PkA 1349.9 vs 356.1 ct.episode-1) were reported across OD and MD cricket. Therefore, this information suggests to the coach that the training regimes for fast bowlers should be specific for the different demands specific to the format of the game employed. Relationships between in-match BioharnessTM data and bowling performance were not clearly established due to the complexities of uncontrollable variables within competitive cricket. In conclusion, the BioharnessTM has demonstrated acceptable validity and reliability in the laboratory and the field setting for all variables (Heart rate, Breathing frequency, Accelerometry, Skin temperature and Posture) but with limitations for heart rate and breathing frequency at the more extreme levels of performance. Furthermore, taking these limitations into account it has successfully been utilised to assess performance and provide further insight into the physiological demands in the professional sport setting. Therefore, this work suggests that coaches and exercise scientists working together should seek to utilise new mobile monitoring technology to access unique insights in to sporting performance which may be unobtainable in the laboratory or a simulated field based event
Assessment of shoulder active range of motion in prone versus supine:A reliability and concurrent validity study
Background: As swimming and surfing are prone dominant sports, it would be more sport specific to assess shoulder active range of motion in this position.
Objectives: To determine the reliability of the inclinometer and HALO© for assessing shoulder active range of motion in supine and prone and the concurrent validity of the HALO©. Concurrent validity is based on the comparison of the HALO© and inclinometer. To determine if active range of motion (AROM) differences exists between prone and supine when assessing shoulder internal (IR) and external rotation (ER).
Design: The design included clinical measurement, reliability and validity. Methods: Thirty shoulders (mean age = 26.8 years) without pathology were evaluated. Measurements were taken in supine and prone with both an inclinometer and HALO© device.
Results: Active ER ROM in prone was significantly higher than in supine when using both devices. Intra-rater reliability (within and between session) intraclass correlation coefficient (ICC) values ranged between 0.82–0.99 for both devices in supine and prone. An ICC test revealed a significant (p \u3c 0.01) correlation for both devices in IR and ER movements (ICC3,1 = 0.87 and ICC3,1 = 0.72), respectively.
Conclusion: This study has shown prone assessment of active ER and IR ROM to be a reliable and appropriate method for prone dominant athletes (swimmers and surfers). In this study greater ER ROM was achieved in prone compared to supine. This finding highlights the importance of standardizing the test position for initial and follow up assessments. Furthermore the HALO© and inclinometer have been shown to be reliable tools that show good concurrent validity
Accelerator performance analysis of the Fermilab Muon Campus
Fermilab is dedicated to hosting world-class experiments in search of new
physics that will operate in the coming years. The Muon g-2 Experiment is one
such experiment that will determine with unprecedented precision the muon
anomalous magnetic moment, which offers an important test of the Standard
Model. We describe in this study the accelerator facility that will deliver a
muon beam to this experiment. We first present the lattice design that allows
for efficient capture, transport, and delivery of polarized muon beams. We then
numerically examine its performance by simulating pion production in the
target, muon collection by the downstream beam line optics, as well as
transport of muon polarization. We finally establish the conditions required
for the safe removal of unwanted secondary particles that minimizes
contamination of the final beam.Comment: 10 p
THE EFFECT OF UPPER LIMB POST-ACTIVATION POTENTIATION ON INCREASES IN VERTICAL JUMP HEIGHT DUE TO AN ARM SWING
Post-activation potentiation (PAP) refers to the phenomenon where muscular performance is improved as a result of contractile history. The aim of this study was to investigate the effects of upper limb PAP on vertical jumping. Firstly, countermovement jumps were performed with (CMJAS) and without an arm swing (CMJ). Participants then carried out 10 dumbbell swings with a weight of 15% of the participant’s body weight and performed further countermovement jumps with an arm swing at 3 (PAP3mins), 6 (PAP6mins) and 9 (PAP9mins) minute rest periods. There was a significant difference (p \u3c 0.05) in jump height, peak vertical GRF and peak concentric power when comparing CMJ to CMJAS. No significant difference was found when comparing a CMJAS to any of the conditions with induced PAP on the upper limbs. This indicates that inducing PAP on the upper limbs does not have a significant effect on jump height
Correlating Infall with Deuterium Fractionation in Dense Cores
We present a survey of HCO+ (3-2) observations pointed towards dense cores
with previous measurements of N(N2D+)/N(N2H+). Of the 26 cores in this survey,
five show the spectroscopic signature of outward motion, nine exhibit neither
inward nor outward motion, eleven appear to be infalling, and one is not
detected. We compare the degree of deuterium fractionation with infall
velocities calculated from the HCO+ spectra and find that those cores with
[D]/[H] > 0.1 are more likely to have the signature of inward motions than
cores with smaller [D]/[H] ratios. Infall motions are also much more common in
cores with masses exceeding their thermal Jeans masses. The fastest infall
velocity measured belongs to one of the two protostellar cores in our survey,
L1521F, and the observed motions are typically on the order of the sound speed.Comment: Accepted to Ap
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