Experimental demonstration of holographic three-dimensional light shaping using a Gerchberg-Saxton algorithm

We use a three-dimensional Gerchberg–Saxton algorithm (Shabtay (2003) Opt. Commun. 226 33) to calculate the Fourier-space representation of physically realizable light beams with arbitrarily shaped three-dimensional intensity distributions. From this representation we extract a phase-hologram pattern that allows us to create such light beams experimentally. We show several examples of experimentally shaped light beams

Vortex sorter for Bose-Einstein condensates

We have designed interferometers that sort Bose-Einstein condensates into their vortex components. The Bose-Einstein condensates in the two arms of the interferometer are rotated with respect to each other through fixed angles; different vortex components then exit the interferometer in different directions. The method we use to rotate the Bose-Einstein condensates involves asymmetric phase imprinting and is itself new. We have modelled rotation through fixed angles and sorting into vortex components with even and odd values of the topological charge of 2-dimensional Bose-Einstein condensates in a number of states (pure or superposition vortex states for different values of the scattering length). Our scheme may have applications for quantum information processing.Comment: 4 pages, high resolution figures can be obtained from the author

The first experimental flight package of an advanced telemetry system with adaptive capability Technical summary report, 1 Jul. 1963 - 15 Feb. 1965

Mechanical design, and environmental and functional testing of advanced telemetry system flight package with adaptive capabilit

The validity of capillary blood sampling in the determination of human growth hormone concentration during exercise in men

This is an open access article - Copyright © 2004 BMJ Publishing Group LtdBACKGROUND: Studies measuring human growth hormone (hGH) in blood during exercise have mainly used venous sampling. The invasive nature of this procedure makes evaluation of hGH impossible in various exercise environments. OBJECTIVE: To determine whether capillary sampling could offer an alternative sampling method. METHODS: Capillary and venous blood samples were collected for determination of hGH at the end of each exercise stage during an incremental exercise test in 16 male club level competitive cyclists (mean (SD) age 30.8 (8.0) years, body mass 72.2 (7.1) kg, body fat 12.9 (3.5)%, peak oxygen consumption 4.18 (0.46) l⋅min−1). Linear regression, from a plot of venous v capillary blood hGH concentration, showed a correlation coefficient of r = 0.986 (p<0.001). When geometric means and log transformations were used, a coefficient of variation of 14.2% was demonstrated between venous and capillary flow for hGH concentration. The mean ratio limits of agreement were 0.62 (1.72)—that is, 95% of the ratios were contained between 0.36 and 1.07, with a mean of 0.62. CONCLUSIONS: Capillary blood sampling is an acceptable alternative to venous sampling for determining hGH concentration during rest and exercise. Sample sites should not be used interchangeably: one site should be chosen and its use standardised

The Impact of Inhaled Salbutamol on Repeated Sprint Ability in Pre- Fatigued Soccer Players

Objectives: Investigate the ergogenic effect of inhaling up to 1600 μg of salbutamol on intermittent running performance in pre-fatigued soccer players. Methods: In a single blind randomised repeated measures design seven male and six female soccer players volunteered to participant. All participants were regularly playing competitive soccer and had no history of asthma. Following familiarisation sessions participants visited the exercise physiology laboratory on three occasions to complete an intermittent running protocol followed by twelve 17.5 m sprints. Prior to each trial participants inhaled either: placebo, 800 μg inhaled salbutamol (SAL800) or 1600 μg inhaled salbutamol (SAL1600). Following completion of the sprints a sample from the first urine passed was analysed for salbutamol concentration. A repeated measures ANOVA was used to compare the mean sprint time, maximal sprint power, peak blood lactate post sprints and post sprint salbutamol urine concentration between conditions. Results: Mean sprint time, maximum power, maximum velocity, peak HR and peak blood lactate during the 17.5 m sprints were not significantly different between treatments in soccer players. There was no significant difference between male and female players in urine drug concentration following SAL800 (mean + SD; 201.47 + 294.47 ng.ml-1 vs. 180.2 + 102.15 ng.ml-1) or SAL1600 (739.24 + 549.21 ng.ml-1 vs. 879.58 + 633.14 ng.ml-1). Three players urine drug concentrations were above the WADA decision limit set at 1200 ng.ml-1. Conclusions: Inhaling up to 1600 μg inhaled salbutamol did not significantly improve repeated sprint performance. However, inhalation of 1600 μg may result in a urine concentration above the current WADA upper limit and decision limit leading to a positive test. Athletes should ensure they use inhaled salbutamol at therapeutic doses to avoid the risk of breaching the WADA decision limit

Hydrogenic retention with high-Z plasma facing surfaces in Alcator C-Mod

The retention of deuterium (D) fuel in the Alcator C-Mod tokamak is studied using a new &#039;static&#039; gas balance method. C-Mod solely employs high-Z molybdenum (Mo) and tungsten (W) for its plasma facing materials, with intermittent application of thin boron (B) films. The primarily Mo surfaces are found to retain large fractions, similar to 20-50%, of the D-2 gas fuelled per quiescent discharge, regardless of whether the Mo surfaces are cleaned of, or partially covered by, B films. Several experiments and calculations show that it is improbable that B retains significant fractions of the fuel. Rather, retention occurs in Mo and W surfaces through ion bombardment, implantation and diffusion to trap sites. Roughly 1% D of the incident ion fluence, Phi(D), to surfaces is retained, and with no indication of the retention rate decreasing after 25 s of integrated plasma exposure. The magnitude of retention is significantly larger than that extrapolated from the results of laboratory studies for either Mo or W. The high levels of D/Mo in the near surface, measured directly post-campaign (similar to 0.01) in tiles and inferred from gas balance, are consistent with trapping sites for fuel retention in the Mo being created, or expanded, by high D atom densities in the near surface which arise as a result of high incident ion fluxes. Differences between C-Mod and laboratory retention results may be due to such factors as the multiply ionized B ions incident on the surface directly creating traps, the condition of Mo (impurities, annealing) and the high-flux densities in the C-Mod divertor which are similar to ITER, but 10-100x those used in laboratory studies. Disruptions produce rapid heating of the surfaces, releasing trapped hydrogenic species into the vessel for recovery. The measurements of the large amount of gas released in disruptions are consistent with the analysis of tiles removed from the vessel post-campaign-the campaign-integrated retention is very low, of order 1000x less than that observed in a single, non-disruptive discharge

Landau levels of cold atoms in non-Abelian gauge fields

The Landau levels of cold atomic gases in non-Abelian gauge fields are analyzed. In particular we identify effects on the energy spectrum and density distribution which are purely due to the non-Abelian character of the fields. We investigate in detail non-Abelian generalizations of both the Landau and the symmetric gauge. Finally, we discuss how these non-Abelian Landau and symmetric gauges may be generated by means of realistically feasible lasers in a tripod scheme.Comment: 13 pages, 9 figure

The Effect of 400 µg Inhaled Salbutamol on 3 km Time Trial Performance in a Low Humidity Environment.

The Objectives of the study were to investigate whether 400 µg inhaled salbutamol influences 3 km running time-trial performance and lung function in eucapnic voluntary hyperpnoea positive (EVH+ve) and negative (EVH-ve) individuals. Fourteen male participants (22.4 ± 1.6yrs; 76.4 ± 8.7kg; 1.80 ± 0.07 m); (7 EVH+ve; 7 EVH-ve) were recruited following written informed consent. All participants undertook an EVH challenge to identify either EVH+ve (↓FEV1>10%) or EVH-ve (↓FEV110% from baseline) in FEV1 following any time-trial. Administration of 400µg inhaled salbutamol does not improve 3 km time-trial performance in either mild EVH+ve or EVH-ve individuals despite significantly increased HR and FEV1

The prevalence and impact of low back pain in pre-professional and professional dancers: a prospective study

Objectives To determine the prevalence of low back pain (LBP) in pre-professional and professional dancers and its impact on dance participation, care-seeking and medication use. Design Prospective cohort study. Setting One pre-professional ballet school, two pre-professional university dance programs, and a professional ballet company. Participants Male and female classical ballet and contemporary dancers. Main outcome measures An initial questionnaire collected demographic and LBP history data. The monthly prevalence of LBP (all episodes, activity limiting episodes and chronic LBP) and impact (activity limitation, care-seeking, and medication use) was collected over a nine-month period. Results 119 dancers participated, which represented 54% of those invited. Activity limiting LBP was reported by 52% of dancers, while chronic LBP was reported by 24%. Seventeen percent of all episodes of LBP resulted in some form of dance activity being completely missed. One-third of the sample reported care-seeking and one-fifth of the sample used medication. A history of LBP was associated with activity limiting LBP (p < 0.01; adjusted odds ratio: 3.98; 95% confidence interval: 1.44, 11.00). Conclusions LBP in dancers was common and had multiple impacts. This study reinforces the need for dancer access to healthcare professionals with expertise in evidence-based LBP prevention and management

The XY Spin-Glass with Slow Dynamic Couplings

We investigate an XY spin-glass model in which both spins and couplings evolve in time: the spins change rapidly according to Glauber-type rules, whereas the couplings evolve slowly with a dynamics involving spin correlations and Gaussian disorder. For large times the model can be solved using replica theory. In contrast to the XY-model with static disordered couplings, solving the present model requires two levels of replicas, one for the spins and one for the couplings. Relevant order parameters are defined and a phase diagram is obtained upon making the replica-symmetric Ansatz. The system exhibits two different spin-glass phases, with distinct de Almeida-Thouless lines, marking continuous replica-symmetry breaking: one describing freezing of the spins only, and one describing freezing of both spins and couplings.Comment: 7 pages, Latex, 3 eps figure