2,728 research outputs found
Modelling surface acoustic wave modulation of the carrier concentration in quantum cascade lasers for broadband tuneability
Correlated physical and mental health summary scores for the SF-36 and SF-12 Health Survey, V.1
<p>Abstract</p> <p>Background</p> <p>The SF-36 and SF-12 summary scores were derived using an uncorrelated (orthogonal) factor solution. We estimate SF-36 and SF-12 summary scores using a correlated (oblique) physical and mental health factor model.</p> <p>Methods</p> <p>We administered the SF-36 to 7,093 patients who received medical care from an independent association of 48 physician groups in the western United States. Correlated physical health (PCS<sub>c</sub>) and mental health (MCS<sub>c</sub>) scores were constructed by multiplying each SF-36 scale z-score by its respective scoring coefficient from the obliquely rotated two factor solution. PCS<sub>c</sub>-12 and MCS<sub>c</sub>-12 scores were estimated using an approach similar to the one used to derive the original SF-12 summary scores.</p> <p>Results</p> <p>The estimated correlation between SF-36 PCS<sub>c </sub>and MCS<sub>c </sub>scores was 0.62. There were far fewer negative factor scoring coefficients for the oblique factor solution compared to the factor scoring coefficients produced by the standard orthogonal factor solution. Similar results were found for PCS<sub>c</sub>-12, and MCS<sub>c</sub>-12 summary scores.</p> <p>Conclusion</p> <p>Correlated physical and mental health summary scores for the SF-36 and SF-12 derived from an obliquely rotated factor solution should be used along with the uncorrelated summary scores. The new scoring algorithm can reduce inconsistent results between the SF-36 scale scores and physical and mental health summary scores reported in some prior studies.</p> <p>(Subscripts C = correlated and UC = uncorrelated)</p
Estimation of Spectroscopic Uncertainty and Correlation in Terahertz Time Domain Spectroscopy
We present a method of calculating the measurement variance-covariance matrix of a spectroscopic sample’s complex refractive index from time-domain statistics in order to estimate uncertainty of a measurement. We compare this method to a numerical analysis and previously derived methodology, and show that our time-based estimate is both accurate and adaptable to complex extraction models
Multilayer Extraction of Complex Refractive Index in Broadband Transmission Terahertz Time-Domain Spectroscopy
In terahertz spectroscopy, multi-layered samples often need to be measured, for instance in a liquid flow cell, and this complicates the extraction of material parameters. We present a spectroscopic parameter extraction algorithm for multilayer samples that can also be used to extract the thickness of an unknown sample laye
Probing temperature- and solvent-dependent protein dynamics using terahertz time-domain spectroscopy
The effect of temperature on the terahertz-frequency-range material properties of lyophilized and single-crystal hen egg-white lysozyme has been measured using terahertz time-domain spectroscopy, with the results presented and discussed in the context of protein and solvent dynamical and glass transitions. Lyophilized hen egg-white lysozyme was measured over a temperature range from 4 to 290 K, and a change in the dynamical behaviour of the sample at around 100 K was observed through a change in the terahertz absorption spectrum. Additionally, the effect of cryoprotectants on the temperature-dependent absorption coefficient is studied, and it is demonstrated that terahertz time-domain spectroscopy is capable of resolving the true glass transition temperature of single-crystal hen egg-white lysozyme at 150 K, which is in agreement with literature values measured using differential scanning calorimetry
The perceptions of undertaking a higher degree alongside orthodontic speciality training: a cross-sectional survey of British Orthodontic Society members
Introduction: In the UK, orthodontic speciality training takes place over three years full-time. In addition to the clinical training, there is an expectation that trainees undertake a higher degree. Currently, there is little evidence regarding the impact of undertaking a higher degree on specialist orthodontists.
Aims: Investigate UK orthodontists' perceptions of undertaking a higher degree alongside speciality training.
Materials and methods: A cross-sectional research study involving the distribution of an anonymous, descriptive, online, questionnaire-based survey between May and June 2021 via the British Orthodontic Society. Data were obtained in relation to the impact of undertaking a higher degree on the completion of speciality training, research skills, delivery of patient care and career opportunities.
Results: In total, 166 questionnaires were completed (approximately 13.3% response rate). Most respondents 'agreed' or 'strongly agreed' that undertaking a higher degree had improved their scientific (77.1%) and critical appraisal skills (80.7%), job prospects (60.2%) and career opportunities (63.9%). Most respondents felt the benefits of the higher degree outweighed the associated costs (65.1%) and was a worthwhile component of training (69.3%).
Conclusions: Specialist orthodontists place a high value on undertaking a higher degree. The results of this questionnaire should be of importance to stakeholders involved in the development of the orthodontic curriculum
Accurate Parameter Extraction From Liquids Measured Using On-chip Terahertz Spectroscopy
We introduce a method for estimating the permittivity of liquid samples measured using integrated microfluidic/planar Goubau line terahertz waveguides, in which simulation results are incorporated with measurement data to enable accurate frequency-dependent analysis
Tunable terahertz band-stop filter using strongly coupled split ring resonators integrated with on-chip waveguide
We have used finite-element methods to design and simulate a tunable terahertz frequency range band-stop filter based on coupled split-ring resonators integrated into planar Goubau-line waveguide. Two split-ring resonators with different geometrical lengths and gap widths were designed to resonate at the same frequency. When the two resonators were coupled, resonance splitting was observed in the transmission spectra controlled by the distance between them. The electric field distribution and surface current modes in the coupled resonators were used to identify the origin of the resonance modes. In order to dynamically tune the coupled resonance frequencies, a cantilevered microelectromechanical scheme is proposed, in which the radius of curvature of one split-ring resonator is adjusted with respect to a fixed second split-ring resonator. The coupling strength of the coupled resonators was investigated as a function of the relative separation of the resonators revealing a dispersion relation that shows anti-crossing of the coupled resonances as the cantilever bends
- …