Feasibility studies for light scattering experiments to determine the velocity relaxation of small particles in a fluid

An approach for measuring the non-Markoffian component in the relaxation mechanism of a Brownian particle is proposed which combines desirable features of both the shock wave experiment and conventional light scattering experiments. It is suggested that the radiation pressure generated by a C.W. laser be used to guide an individual spherical particle to terminal velocity. At an appropriate time, the beam intensity is suddenly lowered to a value at which the radiation pressure is negligible, and the ensuing velocity relaxation is measured directly

Water formation at low temperatures by surface O2 hydrogenation II: the reaction network

Water is abundantly present in the Universe. It is the main component of interstellar ice mantles and a key ingredient for life. Water in space is mainly formed through surface reactions. Three formation routes have been proposed in the past: hydrogenation of surface O, O2, and O3. In a previous paper [Ioppolo et al., Astrophys. J., 2008, 686, 1474] we discussed an unexpected non-standard zeroth-order H2O2 production behaviour in O2 hydrogenation experiments, which suggests that the proposed reaction network is not complete, and that the reaction channels are probably more interconnected than previously thought. In this paper we aim to derive the full reaction scheme for O2 surface hydrogenation and to constrain the rates of the individual reactions. This is achieved through simultaneous H-atom and O2 deposition under ultra-high vacuum conditions for astronomically relevant temperatures. Different H/O2 ratios are used to trace different stages in the hydrogenation network. The chemical changes in the forming ice are followed by means of reflection absorption infrared spectroscopy (RAIRS). New reaction paths are revealed as compared to previous experiments. Several reaction steps prove to be much more efficient (H + O2) or less efficient (H + OH and H2 + OH) than originally thought. These are the main conclusions of this work and the extended network concluded here will have profound implications for models that describe the formation of water in space.Comment: 1 page, 1 figur

Tresillo: A rhythmic framework connecting differing rhythmic styles

This paper examines the origins of the rhythm known as tresillo. Through transcriptions and analysis an examination will be made noting the systematic use of this rhythm in musical structures from Africa, Brazil and Cuba. This paper also explores the roots of tresillo as stemming from the African 3:2 cross-rhythm and the evolution of clave from the 12-bell pattern. Finally the challenging aspects of "swing" in non-Western, Afro-centric music are discussed. A variety of sources were used to gain the necessary information about tresillo and the music presented: books, dissertations and journals written by ethnomusicologists, interviews and lessons with master teachers and information found on the world wide web. Through this paper, I hope to provide insight into more accurate performance practice of the rhythms presented, and the evolution of tresillo and clave, which is relevant in a musical world that is being ever increasingly blended with different influences from around the globe

THE INFRARED SPECTRA OF MATRIX ISOLATED ALKALI METAL HYDROXIDES

Author Institution: National Bureau of Standards, Washington, D.C.The infrared spectra of matrix isolated RbOH, RbOD, NaOH, and NaOD have been observed. Both the alkali metal oxygen stretch, $\nu_{1}$, and the bending mode, $\nu_{2}$, have been assigned for each species. Combination of the results of this study with the microwave measurements for RbOH and RbOD indicates an essentially linear structure for these species. The isotope shift observed for NaOH coupled with reasonable bond lengths indicates an equilibrium configuration of NaOH which probably does not deviate significantly from linearity. These results are consistent with our previously reported results for CsOH

Biometrics Takes Off—Fight Between Privacy and Aviation Security Wages On

In the last two decades, the Department of Homeland Security (DHS) has implemented a variety of new screening and identity verification methods in U.S. airports through its various agencies such as the Transportation Security Administration (TSA) and Customs and Border Protection (CBP). In particular, biometric technology has become a focal point of aviation security advances. TSA, CBP, and even private companies have started using fingerprint, iris, and facial scans to verify travelers’ identities, not only to enhance security but also to improve the travel experience. This Comment examines how DHS, its agencies, and private companies are using biometric technology for aviation security. It then considers the most common privacy concerns raised by the expanded use of biometric technology: data breaches, function creep, and data sharing. As biometric technology is new and continually developing, the scope and extent of privacy threats cannot be completely quantified. However, a combination of new legislation, technological solutions, and independent oversight may be an effective way to protect both biometric data and traveler privacy while maintaining the benefits of enhanced security

THE REACTION OF LITHIUM WITH CICN: THE INFRARED SPECTRUM OF MATRIX ISOLATED LiCN.

Author Institution: National Bureau of Standards, Washington D.C.The infrared spectra of species obtained from the reactions of lithium atoms with ClCN have been observed in a low temperature argon matrix. With the help of isotopic substitution the spectral features can be interpreted to yield vibrational frequencies of LiCN and LiNC