Reliability of measures of lower body strength and speed in academy male adolescent soccer players:Test reliability in elite adolescent footballers

The Nordbord and ForceFrame represent a practical and time efficient means of assessing eccentric hamstring and isometric adductor strength in the large number of squads and players associated with youth soccer academies, yet measurement reliability in this population is unexamined. Therefore, over a period of four days, with no less than 24 hours and no more than 48 hours between trials, 37 players (age: 14.7 ± 0.8 years; stature: 168.7 ± 7.8 cm; mass: 57.7 ± 9.1 kg; maturity offset: 0.8 ± 0.9 years) were assessed for eccentric hamstring strength (force, torque), isometric adductor strength (long and short lever positions) and 30-m sprint (5 m, 10 m, and 20 m splits), using the Nordbord, ForceFrame and electronic timing gates, respectively on three separate occasions. Relative reliability (intraclass correlation coefficient, [ICC]) was rated good for all Nordbord (range: 0.86 to 0.89) and ForceFrame (0.78 to 0.85) measures and ranged from moderate (0.53) to excellent (0.93) for the speed measures, improving with increased distance. Absolute reliability (standard error of the measurement [%SEM]) ranged from 7% to 8% (Nordbord), 3% to 11% (ForceFrame), and 1% to 4% (sprints). Our data provide the first Nordbord and ForceFrame reliability estimates in adolescent soccer academy players. To interpret test sensitivity, practitioners are encouraged to interpret our estimates of absolute reliability against meaningful change values derived from personal experience and evidence-based knowledge and not against absolute or standardized thresholds

Linear programming can help identify practical solutions to improve the nutritional quality of food aid.

OBJECTIVES: To assess the nutritional quality of food aid delivered by food banks in France and to identify practical modifications to improve it. DESIGN: National-level data were collected for all food aid distributed by French food banks in 2004, and its nutrient content per 2000 kcal was estimated and compared with French recommendations for adults. Starting with the actual donation and allowing new foods into the food aid donation, linear programming was used to identify the minimum changes required in the actual donation to achieve the French recommendations. RESULTS: French food-bank-delivered food aid does not achieve the French recommendations for dietary fibre, ascorbic acid, vitamin D, folate, magnesium, docosahexaenoic acid, alpha-linolenic acid and the percentage of energy from saturated fatty acids. Linear programming analysis showed that these recommendations are achievable if more fruits, vegetables, legumes and fish were collected and less cheese, refined cereals and foods rich in fat, sugar and/or salt. In addition, new foods not previously collected are needed, particularly nuts, wholemeal bread and rapeseed oil. These changes increased the total edible weight (42%) and economic value (55%) of the food aid donation, with one-third of its edible weight coming from fruits and vegetables, one-third from staples, one-quarter from dairy products and approximately a tenth from meat/fish/eggs. CONCLUSIONS: Important changes in the types and amounts of food collected will improve the nutritional quality of food-bank-delivered food aid in France. Such changes are recommended to improve the diets of deprived French populations

New Constraints on the Lyman Continuum Escape Fraction at z~1.3

We examine deep far-ultraviolet (1600 Angstrom) imaging of the Hubble Deep Field-North (HDFN) and the Hubble Ultra Deep Field (HUDF) to search for leaking Lyman continuum radiation from starburst galaxies at z~1.3. There are 21 (primarily sub-L*) galaxies with spectroscopic redshifts between 1.1<z<1.5 and none are detected in the far-UV. We fit stellar population templates to the galaxies' optical/near-infrared SEDs to determine the starburst age and level of dust attenuation, giving an accurate estimate of the intrinsic Lyman continuum ratio, f_1500/f_700, and allowing a conversion from f_700 limits to relative escape fractions. We show that previous high-redshift studies may have underestimated the amplitude of the Lyman Break, and thus the relative escape fraction, by a factor of ~2. Once the starburst age and intergalactic HI absorption are accounted for, 18 galaxies in our sample have limits to the relative escape fraction, f_esc,rel < 1.0 with some limits as low as f_esc,rel < 0.10 and a stacked limit of f_esc,rel < 0.08. This demonstrates, for the first time, that most sub-L* galaxies at high redshift do not have large escape fractions. When combined with a similar study of more luminous galaxies at the same redshift we show that, if all star-forming galaxies at z~1 have similar relative escape fractions, the value must be less than 0.14 (3 sigma). We also show that less than 20% (3 sigma) of star-forming galaxies at z~1 have relative escape fractions near unity. These limits contrast with the large escape fractions found at z~3 and suggest that the average escape fraction has decreased between z~3 and z~1. (Abridged)Comment: Accepted for publication in ApJ. aastex format. 39 pages, 11 figure

Isotopic characteristics of the Garonne River and its tributaries

The Garonne is the largest river in the south-west of France, and its drainage basin stretches between the Pyrenees and the Massif Central mountains. Until now, no water stable isotope study has been performed on the whole Garonne river basin which is composed of different geological substrata, and where the water resources are limited during the dry summer period. This study focuses on the Garonne river and its tributaries from the Pyre´ne´es foothill upstream to its confluence with the Lot River downstream. The aim of the study is to determine the origins of the surface waters using their chemical and stable isotopic compositions (18O, D and 13C), to better understand their circulation within the drainage basin and to assess the anthropogenic influences. The Garonne displays a specific 18O seasonal effect, and keeps its Pyre´nean characteristics until its confluence with the Tarn River. The difference in the dissolved inorganic carbon (DIC) comes mainly from the change in lithology between the Pyre´ne´es and the Massif Central mountains. Agriculture activity is only detected in the small tributaries

A study of the X-rayed outflow of APM 08279+5255 through photoionization codes

We present new results from our study of the X-rayed outflow of the z = 3.91 gravitationally lensed broad absorption line (BAL) quasar APM 08279+5255. These results are based on spectral fits to all the long exposure observations of APM 08279+5255 using a new quasar-outflow model. This model is based on cloudy simulations of a near-relativistic quasar outflow. The main conclusions from our multi-epoch spectral re-analysis of Chandra, XMM-Newton and Suzaku observations of APM 08279+5255 are: 1) In every observation we confirm the presence of two strong features, one at rest-frame energies between 1-4 keV, and the other between 7-18 keV. 2) We confirm that the low-energy absorption (1-4 keV rest-frame) arises from a low-ionization absorber with logNH~23 and the high-energy absorption (7-18 keV rest-frame) arises from highly ionized (3>log xi>4; where xi is the ionization parameter) iron in a near-relativistic outflowing wind. Assuming this interpretation, we find that the velocities on the outflow could get up to ~0.7c. 3) We confirm a correlation between the maximum outflow velocity and the photon index and find possible trends between the maximum outflow velocity and the X-ray luminosity, and between the total column density and the photon index. We performed calculations of the force multipliers of material illuminated by absorbed power laws and a Mathews-Ferland SED. We found that variations of the X-ray and UV parts of the SEDs and the presence of a moderate absorbing shield will produce important changes in the strength of the radiative driving force. These results support the observed trend found between the outflow velocity and X-ray photon index in APM 08279+5255. If this result is confirmed it will imply that radiation pressure is an important mechanism in producing quasar outflows.Comment: Paper accepted in the Astrophysical journa

The WSRT wide-field HI survey: II. Local Group features

We have used the WSRT to carry out an unbiased wide-field survey of HI emission features, achieving an RMS sensitivity of about 18 mJy/Beam at a velocity resolution of 17 km/s over 1800 deg^2. In this paper we present our HI detections at negative velocities which could be distinguished from the Galactic foreground. Fully 29% of the entire survey area has high velocity HI emission with N_HI exceeding our 3 sigma limit of about 1.5x10^17cm^-2 over 30 km/s. A faint population of discrete HVCs is detected in the immediate vicinity of M31 which spans a large fraction of the M31 rotation velocity. This class of features is confined to about 12 deg (160 kpc) projected radius of M31 and appears to be physically associated. We detect a diffuse northern extension of the Magellanic Stream (MS) from at least Dec=+20 to +40 deg., which then loops back toward the south. Recent numerical simulations had predicted just such an MS extension corresponding to the apo-galacticon portion of the LMC/SMC orbit at a distance of 125 kpc. A faint bridge of HI emission appears to join the systemic velocities of M31 with that of M33 and continues beyond M31 to the north-west. This may be the first detection of HI associated with the warm-hot intergalactic medium (WHIM). The distribution of peculiar velocity HI associated with M31 can be described by a projected exponential of 25 kpc scale-length and 5x10^17cm^-2 peak column density. We present the distribution function of N_HI in the extended M31 environment, which agrees well with the low red-shift QSO absorption line data over the range log(N_HI)=17.2 to 21.9. Our data extend this comparison about two orders of magnitude lower than previously possible and provide the first image of the Lyman limit absorption system associated with an L* galaxy. (abridged)Comment: 16 pages, 12 figures, accepted for publication in A&