The Athletic Profile of Fast Bowling in Cricket : A Review

Cricket is a global sport played in over 100 countries with elite performers attracting multimillion dollar contracts. Therefore, performers maintaining optimum physical fitness and remaining injury free is important. Fast bowlers have a vital position in a cricket team, and there is an increasing body of scientific literature that has reviewed this role over the past decade. Previous research on fast bowlers has tended to focus on biomechanical analysis and injury prevention in performers. However, this review aims to critically analyze the emerging contribution of physiological-based literature linked to fast bowling in cricket, highlight the current evidence related to simulated and competitive in-match performance, and relate this practically to the conditioning coach. Furthermore, the review considers limitations with past research and possible avenues for future investigation. It is clear with the advent of new applied mobile monitoring technology that there is scope for more ecologically valid and longitudinal exploration capturing in-match data, providing quantification of physiological workloads, and analysis of the physical demands across the differing formats of the game. Currently, strength and conditioning specialists do not have a critical academic resource with which to shape professional practice, and this review aims to provide a starting point for evidence in the specific areaPeer reviewedFinal Accepted Versio

Indications for grain growth and mass decrease in cold dust disks around Classical T Tauri stars in the MBM 12 young association

We report detection of continuum emission at 850 and 450 micron from disks around four Classical T Tauri stars in the MBM 12 (L1457) young association. Using a simple model we infer masses of 0.0014-0.012 M_sun for the disk of LkHa 263 ABC, 0.005-0.021 M_sun for S18 ABab, 0.03-0.18 M_sun for LkHa 264 A, and 0.023-0.23 M_sun for LkHa 262. The disk mass found for LkHa 263 ABC is consistent with the 0.0018 M_sun inferred from the scattered light image of the edge-on disk around component C. Comparison to earlier 13CO line observations indicates CO depletion by up to a factor 300 with respect to dark-cloud values. The spectral energy distributions (SED) suggest grain growth, possibly to sizes of a few hundred micron, but our spatially unresolved data cannot rule out opacity as an explanation for the SED shape. Our observations show that these T Tauri stars are still surrounded by significant reservoirs of cold material at an age of 1-5 Myr. We conclude that the observed differences in disk mass are likely explained by binary separation affecting the initial value. With available accretion rate estimates we find that our data are consistent with theoretical expectations for viscously evolving disks having decreased their masses by ~30%.Comment: 15 pages, 3 figures, uses aastex. ApJ Letters, in pres

Bioharness multivariable monitoring device. Part I: Validity

The BioharnessTM monitoring system may provide physiological information on human performance but there is limited information on its validity. The objective of this study was to assess the validity of all 5 BioharnessTM variables using a laboratory based treadmill protocol. 22 healthy males participated. Heart rate (HR), Breathing Frequency (BF) and Accelerometry (ACC) precision were assessed during a discontinuous incremental (0- 12 km·h-1) treadmill protocol. Infra-red skin temperature (ST) was assessed during a 45 min-1 sub-maximal cycle ergometer test, completed twice, with environmental temperature controlled at 20 ±0.1 °C and 30 ± 0.1 °C. Posture (P) was assessed using a tilt table moved through 160°. Adopted precision of measurement devices were; HR: Polar T31 (Polar Electro), BF: Spirometer (Cortex Metalyser), ACC: Oxygen expenditure (Cortex Metalyser), ST: Skin thermistors (Grant Instruments), P:Goniometer (Leighton Flexometer). Strong relationships (r = .89 to .99, p \u3c 0.01) were reported for HR, BF, ACC and P. Limits of agreement identified differences in HR (-3.05±32.20 b·min-1), BF (-3.46 ± 43.70 br·min-1) and P (0.20 ± 2.62°). ST established a moderate relationships (-0.61 ± 1.98 °C; r = 0.76, p \u3c 0.01). Higher velocities on the treadmill decreased the precision of measurement, especially HR and BF. Global results suggest that the BioharressTM is a valid multivariable monitoring device within the laboratory environment

Bioharness multivariable monitoring device. Part II: Reliability

The BioharnessTM monitoring system may provide physiological information on human performance but the reliability of this data is fundamental for confidence in the equipment being used. The objective of this study was to assess the reliability of each of the 5 BioharnessTM variables using a treadmill based protocol. 10 healthy males participated. A between and within subject design to assess the reliability of Heart rate (HR), Breathing Frequency (BF), Accelerometry (ACC) and Infra-red skin temperature (ST) was completed via a repeated, discontinuous, incremental treadmill protocol. Posture (P) was assessed by a tilt table, moved through 160o. Between subject data reported low Coefficient of Variation (CV) and strong correlations(r) for ACC and P (CV\u3c 7.6; r = 0.99, p \u3c 0.01). In contrast, HR and BF (CV~19.4; r~0.70, p \u3c 0.01) and ST (CV 3.7; r = 0.61, p \u3c 0.01), present more variable data. Intra and inter device data presented strong relationships (r \u3e 0.89, p \u3c 0.01) and low CV

Protoplanetary Disk Masses in the Young NGC 2024 Cluster

We present the results from a Submillimeter Array survey of the 887 micron continuum emission from the protoplanetary disks around 95 young stars in the young cluster NGC 2024. Emission was detected from 22 infrared sources, with flux densities from ~5 to 330 mJy; upper limits (at 3sigma) for the other 73 sources range from 3 to 24 mJy. For standard assumptions, the corresponding disk masses range from ~0.003 to 0.2Msolar, with upper limits at 0.002--0.01Msolar. The NGC 2024 sample has a slightly more populated tail at the high end of its disk mass distribution compared to other clusters, but without more information on the nature of the sample hosts it remains unclear if this difference is statistically significant or a superficial selection effect. Unlike in the Orion Trapezium, there is no evidence for a disk mass dependence on the (projected) separation from the massive star IRS2b in the NGC 2024 cluster. We suggest that this is due to either the cluster youth or a comparatively weaker photoionizing radiation field.Comment: ApJ, in pres

ALMA Observations of the Orion Proplyds

We present ALMA observations of protoplanetary disks ("proplyds") in the Orion Nebula Cluster. We imaged 5 individual fields at 856um containing 22 HST-identified proplyds and detected 21 of them. Eight of those disks were detected for the first time at submillimeter wavelengths, including the most prominent, well-known proplyd in the entire Orion Nebula, 114-426. Thermal dust emission in excess of any free-free component was measured in all but one of the detected disks, and ranged between 1-163 mJy, with resulting disk masses of 0.3-79 Mjup. An additional 26 stars with no prior evidence of associated disks in HST observations were also imaged within the 5 fields, but only 2 were detected. The disk mass upper limits for the undetected targets, which include OB stars, theta1Ori C and theta1Ori F, range from 0.1-0.6 Mjup. Combining these ALMA data with previous SMA observations, we find a lack of massive (>3 Mjup) disks in the extreme-UV dominated region of Orion, within 0.03 pc of O-star theta1Ori C. At larger separations from theta1Ori C, in the far-UV dominated region, there is a wide range of disk masses, similar to what is found in low-mass star forming regions. Taken together, these results suggest that a rapid dissipation of disk masses likely inhibits potential planet formation in the extreme-UV dominated regions of OB associations, but leaves disks in the far-UV dominated regions relatively unaffected.Comment: ApJ, in pres

ALMA Observations of Asymmetric Molecular Gas Emission from a Protoplanetary Disk in the Orion Nebula

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of molecular line emission from d216-0939, one of the largest and most massive protoplanetary disks in the Orion Nebula Cluster (ONC). We model the spectrally resolved HCO$^+$ (4--3), CO (3--2), and HCN (4--3) lines observed at 0\farcs5 resolution to fit the temperature and density structure of the disk. We also weakly detect and spectrally resolve the CS (7--6) line but do not model it. The abundances we derive for CO and HCO$^+$ are generally consistent with expected values from chemical modeling of protoplanetary disks, while the HCN abundance is higher than expected. We dynamically measure the mass of the central star to be $2.17\pm0.07\,M_\odot$ which is inconsistent with the previously determined spectral type of K5. We also report the detection of a spatially unresolved high-velocity blue-shifted excess emission feature with a measurable positional offset from the central star, consistent with a Keplerian orbit at $60\pm20\,\mathrm{au}$. Using the integrated flux of the feature in HCO$^+$ (4--3), we estimate the total H$_2$ gas mass of this feature to be at least $1.8-8\,M_\mathrm{Jupiter}$, depending on the assumed temperature. The feature is due to a local temperature and/or density enhancement consistent with either a hydrodynamic vortex or the expected signature of the envelope of a forming protoplanet within the disk.Comment: 19 pages, 12 figures, accepted for publication in A

Eigenvalue distributions for some correlated complex sample covariance matrices

The distributions of the smallest and largest eigenvalues for the matrix product $Z^\dagger Z$, where $Z$ is an $n \times m$ complex Gaussian matrix with correlations both along rows and down columns, are expressed as $m \times m$ determinants. In the case of correlation along rows, these expressions are computationally more efficient than those involving sums over partitions and Schur polynomials reported recently for the same distributions.Comment: 11 page

Field based reliability and validity of the Bioharness multivariable monitoring device

The BioharnessTM device is designed for monitoring physiological variables in free-living situations but has only been proven to be reliable and valid in a laboratory environment. Therefore, this study aimed to determine the reliability and validity of the BioharnessTM using a field based protocol. Twenty healthy males participated. Heart rate (HR), breathing frequency (BF) and accelerometry (ACC) were assessed by simultaneous measurement of two BioharnessTM devices and a test-retest of a discontinuous incremental walk-jog-run protocol (4 – 11 km·h-1) completed in a sports hall. Adopted precision of measurement devices were; HR: Polar T31 (Polar Electro), BF: Spirometer (Cortex Metalyser), ACC: Oxygen expenditure (Cortex Metalyser). For all data, precision of measurement reported good relationships (r = 0.61 to 0.67, p \u3c 0.01) and large Limits of Agreement for HR (\u3e79.2 b·min-1) and BF (\u3e54.7 br·min-1). ACC presented excellent precision (r = 0.94, p \u3c 0.01). Results for HR (r= ~0.91, p \u3c 0.01: CV \u3c7.6) and ACC (r \u3e 0.97, p \u3c 0.01; CV \u3c14.7) suggested these variables are reliable. BF presented more variable data (r = 0.46-0.61, p \u3c 0.01; CV \u3c 23.7). As velocity of movement increased (\u3e8 km·h-1) data became more erroneous. A data cleaning protocol removed gross errors in the data analysis and subsequent reliability and validity statistics improved across all variables. In conclusion, the BioharnessTM HR and ACC variables have demonstrated reliability and validity in a field setting, though data collected at higher velocities should be treated with caution. Measuring human physiological responses in a field based environment allows for more ecologically valid data to be collected and devices such as the BioharnessTM could be used by exercise professionals to begin to further investigate this area

Field based reliability and validity of the Bioharness multivariable monitoring device

The Bioharness™ device is designed for monitoring physiological variables in free-living situations but has only been proven to be reliable and valid in a laboratory environment. Therefore, this study aimed to determine the reliability and validity of the Bioharness™ using a field based protocol. Twenty healthy males participated. Heart rate (HR), breathing frequency (BF) and accelerometry (ACC) were assessed by simultaneous measurement of two Bioharness™ devices and a test-retest of a discontinuous incremental walk-jog-run protocol (4 - 11 km·h-1) completed in a sports hall. Adopted precision of measurement devices were; HR: Polar T31 (Polar Electro), BF: Spirometer (Cortex Metalyser), ACC: Oxygen expenditure (Cortex Metalyser). For all data, precision of measurement reported good relationships (r = 0.61 to 0.67, p 79.2 b·min-1) and BF (>54.7 br·min-1). ACC presented excellent precision (r = 0.94, p 0.97, p 8 km·h-1) data became more erroneous. A data cleaning protocol removed gross errors in the data analysis and subsequent reliability and validity statistics improved across all variables. In conclusion, the Bioharness™ HR and ACC variables have demonstrated reliability and validity in a field setting, though data collected at higher velocities should be treated with caution. Measuring human physiological responses in a field based environment allows for more ecologically valid data to be collected and devices such as the Bioharness™ could be used by exercise professionals to begin to further investigate this area