Velocity measurements by laser resonance fluorescence

The photonburst correlation method was used to detect single atoms in a buffer gas. Real time flow velocity measurements with laser induced resonance fluorescence from single or multiple atoms was demonstrated and this method was investigated as a tool for wind tunnel flow measurement. Investigations show that single atoms and their real time diffusional motion on a buffer gas can be measured by resonance fluorescence. By averaging over many atoms, flow velocities up to 88 m/s were measured in a time of 0.5 sec. It is expected that higher flow speeds can be measured and that the measurement time can be reduced by a factor of 10 or more by careful experimental design. The method is clearly not ready for incorporation in high speed wind tunnels because it is not yet known whether the stray light level will be higher or lower, and it is not known what detection efficiency can be obtained in a wind tunnel situation

Measurement of the hyperfine structure of the 4d2D 3/2,5/2 levels and isotope shifts of the 4p2p 3/2 ? 4d2D3/2 and 4p2p 3/2 ? 4d2D5/2 transitions in gallium 69 and 71

The hyperfine structure of the 4d2D3/2,5/2 levels of 69,71Ga is determined. The 4p2P3/2 ? 4d2D3/2 (294.50-nm) and 4p2P3/2 ? 4d2D5/2 (294.45-nm) transitions are studied by laser-induced fluorescence in an atomic Ga beam. The hyperfine A constant measured for the 4d2D5/2 level is 77.3 ± 0.9 MHz for 69Ga and 97.9 ± 0.7 MHz for 71Ga (3s errors). The A constant measured for the 4d2D3/2 level is -36.3 ± 2.2 MHz for 69Ga and -46.2 ± 3.8 MHz for 71Ga. These measurements correct sign errors in the previous determination of these constants. For 69Ga the hyperfine B constants measured for the 4d2D5/2 and the 4d2D 3/2 levels are 5.3 ± 4.1 MHz and 4.6 ± 4.2 MHz, respectively. The isotope shift is determined to be 114 ± 8 MHz for the 4p2P3/2 ? 4d2D3/2 transition and 115 ± 7 MHz for the 4p2P3/2 ± 4d 2D5/2 transition. The lines of 71Ga are shifted to the blue. This is in agreement with previous measurement

A review of RCTs in four medical journals to assess the use of imputation to overcome missing data in quality of life outcomes

Background: Randomised controlled trials (RCTs) are perceived as the gold-standard method for evaluating healthcare interventions, and increasingly include quality of life (QoL) measures. The observed results are susceptible to bias if a substantial proportion of outcome data are missing. The review aimed to determine whether imputation was used to deal with missing QoL outcomes. Methods: A random selection of 285 RCTs published during 2005/6 in the British Medical Journal, Lancet, New England Journal of Medicine and Journal of American Medical Association were identified. Results: QoL outcomes were reported in 61 (21%) trials. Six (10%) reported having no missing data, 20 (33%) reported ≤ 10% missing, eleven (18%) 11%–20% missing, and eleven (18%) reported >20% missing. Missingness was unclear in 13 (21%). Missing data were imputed in 19 (31%) of the 61 trials. Imputation was part of the primary analysis in 13 trials, but a sensitivity analysis in six. Last value carried forward was used in 12 trials and multiple imputation in two. Following imputation, the most common analysis method was analysis of covariance (10 trials). Conclusion: The majority of studies did not impute missing data and carried out a complete-case analysis. For those studies that did impute missing data, researchers tended to prefer simpler methods of imputation, despite more sophisticated methods being available.The Health Services Research Unit is funded by the Chief Scientist Office of the Scottish Government Health Directorate. Shona Fielding is also currently funded by the Chief Scientist Office on a Research Training Fellowship (CZF/1/31)

A review of RCTs in four medical journals to assess the use of imputation to overcome missing data in quality of life outcomes

Peer reviewedPublisher PD

Mobility of thorium ions in liquid xenon

We present a measurement of the $^{226}$Th ion mobility in LXe at 163.0 K and 0.9 bar. The result obtained, 0.240$\pm$0.011 (stat) $\pm$0.011 (syst) cm$^{2}$/(kV-s), is compared with a popular model of ion transport.Comment: 6.5 pages,

Daily functioning and self-management in patients with chronic low back pain after an intensive cognitive behavioral programme for pain management

Chronic low back pain (CLBP) is associated with persistent or recurrent disability which results in high costs for society. Cognitive behavioral treatments produce clinically relevant benefits for patients with CLBP. Nevertheless, no clear evidence for the most appropriate intervention is yet available. The purpose of this study is to evaluate the mid-term effects of treatment in a cohort of patients with CLBP participating in an intensive pain management programme. The programme provided by RealHealth-Netherlands is based on cognitive behavioral principles and executed in collaboration with orthopedic surgeons. Main outcome parameters were daily functioning (Roland and Morris Disability Questionnaire and Oswestry Disability Questionnaire), self-efficacy (Pain Self-Efficacy Questionnaire) and quality of life (Short Form 36 Physical Component Score). All parameters were measured at baseline, last day of residential programme and at 1 and 12 months follow-up. Repeated measures analysis was applied to examine changes over time. Clinical relevance was examined using minimal clinical important differences (MCID) estimates for main outcomes. To compare results with literature effect sizes (Cohen’s d) and Standardized Morbidity Ratios (SMR) were determined. 107 patients with CLBP participated in this programme. Mean scores on outcome measures showed a similar pattern: improvement after residential programme and maintenance of results over time. Effect sizes were 0.9 for functioning, 0.8 for self-efficacy and 1.3 for physical functioning related quality of life. Clinical relevancy: 79% reached MCID on functioning, 53% on self-efficacy and 80% on quality of life. Study results on functioning were found to be 36% better and 2% worse when related to previous research on, respectively, rehabilitation programmes and spinal surgery for similar conditions (SMR 136 and 98%, respectively). The participants of this evidence-based programme learned to manage CLBP, improved in daily functioning and quality of life. The study results are meaningful and comparable with results of spinal surgery and even better than results from less intensive rehabilitation programmes

Measurement of the Spectral Shape of the beta-decay of 137Xe to the Ground State of 137Cs in EXO-200 and Comparison with Theory

We report on a comparison between the theoretically predicted and experimentally measured spectra of the first-forbidden non-unique $\beta$-decay transition ^{137}\textrm{Xe}(7/2^-)\to\,^{137}\textrm{Cs}(7/2^+). The experimental data were acquired by the EXO-200 experiment during a deployment of an AmBe neutron source. The ultra-low background environment of EXO-200, together with dedicated source deployment and analysis procedures, allowed for collection of a pure sample of the decays, with an estimated signal-to-background ratio of more than 99-to-1 in the energy range from 1075 to 4175 keV. In addition to providing a rare and accurate measurement of the first-forbidden non-unique $\beta$-decay shape, this work constitutes a novel test of the calculated electron spectral shapes in the context of the reactor antineutrino anomaly and spectral bump.Comment: Version as accepted by PR

A magnetically-driven piston pump for ultra-clean applications

A magnetically driven piston pump for xenon gas recirculation is presented. The pump is designed to satisfy extreme purity and containment requirements, as is appropriate for the recirculation of isotopically enriched xenon through the purification system and large liquid xenon TPC of EXO-200. The pump, using sprung polymer gaskets, is capable of pumping more than 16 standard liters per minute (SLPM) of xenon gas with 750 torr differential pressure.Comment: 6 pages, 5 figure