We have used vibrational sum-frequency spectroscopy to provide the first measurement of the spectrum and orientation of the polar headgroup of a charged alkyl surfactant at the air/water interface. Sum-frequency spectra of sodium dodecyl sulfate (SDS) are used to arrive at all participating elements of the second-order susceptibility tensor. We use these chi(2) elements, together with calculate...

We demonstrate spectral and polarization modulation of chemically synthesized core-shell CdSe/ZnS quantum dots (QDs) embedded in a one-dimensional photonic cavity formed by a cholesteric liquid crystal (CLC) matrix. A Cano-wedge cell varies the pitch of the CLC leading to the formation of Grandjean steps. This spatially tunes the photonic stop band, changing the resonance condition and continuo...

Representing the H1 and ZEUS collaborations Recent results from the HERA experiments H1 and ZEUS on the exclusive production of heavy vector mesons V in ep collisions, i.e. the reaction ep ! eV p, are reviewed. The new measurements 1 include photoproduction of J== at larger photon-proton centre-of-mass energy W than previously, more precise data on J== electroproduction and (2S) photoproduction...

Purpose The purpose of this article is to evaluate optic nerve head (ONH) characteristics in an ethnically diverse cohort of young U.S. adults. Methods In this study, 409 myopes and 206 nonmyopes (median age 22 years) completed measures including biometry and spectral domain optical coherence tomography from enface (ovality and torsion) and cross-sectional (tilt and crescent width) scans. Ass...

[1] Using line‐of‐sight measurements of horizontal plasma drift from the Super Dual Auroral Radar Network (SuperDARN) located in the Northern and Southern hemispheres over a period extending from 1998 to 2002, statistical models of the high‐latitude convection electric field are derived for various ranges of interplanetary magnetic field (IMF) magnitude and orientation and for several ranges of...

Two preliminary measurements of beauty production in events with two jets at HERA are presented. The first exploits the new ZEUS microvertex detector to measure the b content of a sample of events with two jets and a muon. The second is a measurement by the H1 collaboration based on inclusive lifetime tagging. The results are in agreement with previous measurements and with QCD predictions. ¡ S...

PURPOSE This study assessed the accuracy of linear and angular measurements on panoramic radiographs taken at different positions in vitro. MATERIALS AND METHODS Two acrylic models were fabricated from a cast with normal occlusion. Straight and 75° mesially and lingually angulated pins were placed, and standardized panoramic radiographs were taken at standard position, at an 8° downward tilt ...

Previous research suggests that nonhuman primates have limited flexibility in the frequency content of their vocalizations, particularly when compared to human speech. Consistent with this notion, several nonhuman primate species have demonstrated noise-induced changes in call amplitude and duration, with no evidence of changes to spectral content. This experiment used broad- and narrow-band no...

This study examines the contrast between (alveo-)palatal stop bursts and velar stop bursts (/c/ vs. /k/), with particular focus on how the contrast between the two is enhanced in Word-initial vs. Word-medial position. Data are presented from nine speakers of Pitjantjatjara, a language of Central Australia. Analyses show that although there are formant differences between palatal and velar stop ...

We discuss the spectral energy distribution of three very low mass objects in Chamaeleon I for which ground-based spectroscopy and photometry as well as ISO measurements in the mid-infrared are available (Comerr on et al. 2000; Persi et al. 2000). One of these stars (Cha H1) is a bona-de brown dwarf, with mass 0.04{0.05 M. We show that the observed emission is very well described by models of c...