A new computer application for teaching sexual history taking to medical students: innovation and evaluation in the UfaceMETM program.

Background: We developed an app (UfaceME) which simultaneously allows patient and clinician to be viewed on a split screen, then replayed and rated on a series of semantic differential scales and the ratings of the clinician of their own response to the interview, and the patient's response, displayed on a graph. Method: We evaluated the app with trials with 14 medical student volunteers who alternated the roles of patient and clinician, using 2 randomly allocated sexual case histories. Semantic differentials for 10 adjectives were examined pre- and post-exercise. There were significant differences in 8 of the 10 adjectives. A focus group with the 14 subjects was also carried out and transcribed. The exercise was repeated with all 175 first-year medical students taking a sexual history. Results: Qualitative data indicated themes of being surprised and educated by non-verbal and verbal responses; seeing how the patient rated their responses; rating and watching discomfort; differences in clinician/patient perceptions and response; and the advantage of feedback. Quantitative data comparing self vs "patient" showed low correlations between perceptions of being "at ease", moderate for appearing "distracted", and high for appearing "engaged". Conclusion: UfaceME was easily understood and used, and the opportunity to replay and rate performance on key semantic scales, and watch and assess verbal and non-verbal performance, including patient rating, provided valuable insight.

Measurement of Lamb wave polarization using a one-dimensional scanning laser vibrometer (L).

A single head scanning laser Doppler vibrometer is used for the estimation of the polarization of the first symmetric (S(0)) and antisymmetric (A(0)) Lamb wave modes. The measurements at two known incidence angles are performed in order to resolve the two components of motion. Filtering in the frequency/wavenumber domain of the response recorded along a scan line separates the contributions from each mode and allows the evaluation of the corresponding elliptical trajectories of particle motion. Comparison between measured and analytically estimated trajectories validates the measurement technique and suggests its application for the development of material characterization and diagnostics tools.

Using cross-correlations of elastic diffuse fields for attenuation tomography of structural damage.

A scanning laser Doppler vibrometer is used to measure, at multiple grid points, the diffuse vibrations (50-150 kHz) propagating over a thin aluminum plate with complex geometry. These diffuse vibrations were generated by a few pulsed laser impacts randomly distributed outside of the measurement grid. The pairwise cross-correlations of the diffuse field recorded at all grid points provided an estimate of the first antisymmetric Lamb mode direct arrival between these grid points. Attenuation tomography imaging of a simulated structural damage is performed based on the relative amplitude variations of these direct arrivals between the damaged and undamaged conditions.

Extracting guided waves from cross-correlations of elastic diffuse fields: applications to remote structural health monitoring.

Due to their apparent complexity, diffuse fields are not commonly used by conventional structural health monitoring methodologies. However, recent theoretical and experimental studies have demonstrated that local Green's functions (GFs) can be estimated from the cross-correlation of elastic diffuse fields (CDFs) recorded between any points of a sensor grid and generated by sources located remotely from the monitoring area. Hence, this CDF technique effectively transforming each measurement point into a virtual elastic source, thus allowing to measure the local structural response (or GF). Theoretical and experimental studies are conducted to assess the broadband performance of the CDF technique for the extraction of low-frequency coherent Lamb waves (4-90 kHz) propagating in a thin aluminum plate of complex geometry using a scanning laser Doppler vibrometer. The coherent signal-to-noise ratio and the accuracy of the phase and group velocity measurements of the coherent A(0) mode obtained from CDF are also measured to quantify the influence of the spatio-temporal characteristics of the recorded diffuse field, the number and spatial configuration of the remote ultrasonic sources, and the influence of incoherent measurement noise (e.g., sensor noise). In addition, a criterion to assess the emergence rate of late coherent coda arrivals from CDF is also formulated.

Off-axis cavity ringdown spectroscopy: application to atmospheric nitrate radical detection.

Atmospheric nitrate radicals (NO3) are detected using off-axis cavity ringdown spectroscopy (CRDS) for the first time to our knowledge with a room-temperature continuous-wave (cw) diode laser operating near 662 nm. A prototype instrument was constructed that achieved a 1sigma absorption sensitivity of 5 x 10(-10) cm(-1) Hz(-1/2), corresponding to a 1.4 part per trillion by volume 2sigma detection limit in 4.6 s at 80 degrees C. This sensitivity is a significant improvement over a recent implementation of off-axis cavity-enhanced absorption spectroscopy and comparable to that of the most advanced cw CRDS and pulsed CRDS applications for atmospheric detection of NO3. A comparison of measurements of ambient air in Fairbanks, Alaska, recorded with the off-axis CRDS instrument and a previously characterized conventional cw CRDS instrument showed good agreement (R2 = 0.97).

Observation and interpretation of a time-delayed mechanism in the hydrogen exchange reaction.

Extensive theoretical and experimental studies have shown the hydrogen exchange reaction H+H2 --> H2+H to occur predominantly through a 'direct recoil' mechanism: the H--H bonds break and form concertedly while the system passes straight over a collinear transition state, with recoil from the collision causing the H2 product molecules to scatter backward. Theoretical predictions agree well with experimental observations of this scattering process. Indirect exchange mechanisms involving H3 intermediates have been suggested to occur as well, but these are difficult to test because bimolecular reactions cannot be studied by the femtosecond spectroscopies used to monitor unimolecular reactions. Moreover, full quantum simulations of the time evolution of bimolecular reactions have not been performed. For the isotopic variant of the hydrogen exchange reaction, H+D2 --> HD+D, forward scattering features observed in the product angular distribution have been attributed to possible scattering resonances associated with a quasibound collision complex. Here we extend these measurements to a wide range of collision energies and interpret the results using a full time-dependent quantum simulation of the reaction, thus showing that two different reaction mechanisms modulate the measured product angular distribution features. One of the mechanisms is direct and leads to backward scattering, the other is indirect and leads to forward scattering after a delay of about 25 femtoseconds.