Non-destructive interferometric characterization of an optical dipole trap

A method for non-destructive characterization of a dipole trapped atomic sample is presented. It relies on a measurement of the phase-shift imposed by cold atoms on an optical pulse that propagates through a free space Mach-Zehnder interferometer. Using this technique we are able to determine, with very good accuracy, relevant trap parameters such as the atomic sample temperature, trap oscillation frequencies and loss rates. Another important feature is that our method is faster than conventional absorption or fluorescence techniques, allowing the combination of high-dynamical range measurements and a reduced number of spontaneous emission events per atom.Comment: 9 pages, 6 figures, submitted to PR

Ultrafast Dynamics of Excited Electronic States in Nitrobenzene Measured by Ultrafast Transient Polarization Spectroscopy.

We investigate ultrafast dynamics of the lowest singlet excited electronic state in liquid nitrobenzene using ultrafast transient polarization spectroscopy, extending the well-known technique of optical Kerr effect spectroscopy to excited electronic states. The third-order nonlinear response of the excited molecular ensemble is measured using a pair of femtosecond pulses following a third femtosecond pulse that populates the S1 excited state. By measuring this response, which is highly sensitive to details of the excited state character and structure, as a function of time delays between the three pulses involved, we extract the dephasing time of the wave packet on the excited state. The dephasing time, measured as a function of time delay after pump excitation, shows oscillations indicating oscillatory wave packet dynamics on the excited state. From the experimental measurements and supporting theoretical calculations, we deduce that the wave packet completely leaves the S1 state potential energy surface after three traversals of the intersystem crossing between the singlet S1 and triplet T2 states

Exploring Typology Categorizations of Male Perpetrators: A Methodology Study

Intimate partner violence (IPV) perpetrators were categorized based on whether they were generally violent (GV) or family only violent (FO) using self-report or arrest records. Classification criteria to assess recidivism in perpetrators of IPV were evaluated herein to determine the incremental validity of using a perpetrator’s criminal history in addition to their self-report information for categorization purposes. The concordance rates for categorizing subtypes of male perpetrators were compared for two methods, namely, self-report versus criminal history data. Categorizations were made based on self-reported history of violence and federal criminal records separately. Between measures consistency was defined as whether or not the self-report categorizations matched federal criminal record categorizations. It was hypothesized that self-report would not be sufficient as the sole method of categorizing male perpetrators, and the use of criminal history data would add to the validity of the categorization system. Self-reports of aggression were higher than criminal records of aggression. Using data sources together may yield the best outcomes for offenders and society. Implications are discussed

Strabismus measurements with novel video goggles

PURPOSE: To assess the validity of a novel, simplified, noninvasive test for strabismus using video goggles. DESIGN: Cross-sectional method comparison study in which the new test, the strabismus video goggles, is compared with the existing reference standard, the Hess screen test. PARTICIPANTS: We studied 41 adult and child patients aged ≥6 years with ocular misalignment owing to congenital or acquired paralytic or comitant strabismus and 17 healthy volunteers. METHODS: All participants were tested with binocular infrared video goggles with built-in laser target projection and liquid crystal display shutters for alternate occlusion of the eyes and the conventional Hess screen test. In both tests, ocular deviations were measured on a 9-point target grid located at 0±15° horizontal and vertical eccentricity. MAIN OUTCOME MEASURES: Horizontal and vertical ocular deviations at 9 different gaze positions of each eye were measured by the strabismus video goggles and the Hess screen test. Agreement was quantified as the intraclass correlation coefficient. Secondary outcomes were the utility of the goggles in patients with visual suppression and in children. RESULTS: There was good agreement between the strabismus video goggles and the Hess screen test in the measurements of horizontal and vertical deviation (intraclass correlation coefficient horizontal 0.83, 95% confidence interval [0.77, 0.88], vertical 0.76, 95% confidence interval [0.68, 0.82]). Both methods reproduced the characteristic strabismus patterns in the 9-point grid. In contrast to Hess screen testing, strabismus video goggle measurements were even possible in patients with comitant strabismus and visual suppression. CONCLUSIONS The new device is simple and is fast and accurate in measuring ocular deviations, and the results are closely correlated with those obtained using the conventional Hess screen test. It can even be used in patients with visual suppression who are not suitable for the Hess screen test. The device can be applied in children as young as 6 years of age

Obstetric outcomes after treatment of periodontal disease during pregnancy: systematic review and meta-analysis

Objective To examine whether treatment of periodontal disease with scaling and root planing during pregnancy is associated with a reduction in the preterm birth rate

Fundamental Spin Interactions Underlying the Magnetic Anisotropy in the Kitaev Ferromagnet CrI3_3

We lay the foundation for determining the microscopic spin interactions in the two-dimensional (2D) ferromagnets by combining our angle-dependent ferromagnetic resonance (FMR) experiments on high quality CrI$_3$ single crystals with theoretical modeling based on symmetries. In the 2D limit, ferromagnetism is stabilized by magnetic anisotropy. We find the largest anisotropy arises from Kitaev interactions of strength $K~\sim-5.2$ meV, larger than the Heisenberg exchange $J~\sim-0.2$ meV. We further discover that the symmetric off-diagonal anisotropy $\Gamma\sim-67.5$ $\mu$eV, though small, plays the crucial role of opening a gap in the magnon spectrum and stabilizing ferromagnetism in the 2D limit. The resolution of the FMR data is sufficient to reveal a $\mu$eV-scale quadrupolar contribution in the $S=3/2$ magnet. Our identification of the interactions underlying ferromagnetism and exchange anisotropies opens paths towards 2D ferromagnets with higher T_\rm{C} and magnetically frustrated quantum spin liquids based on Kitaev physics.Comment: 5 pages, 4 figure