Genomic organization of the mouse T-cell receptor β-chain gene family

We have combined three different methods, deletion mapping of T-cell lines, field-inversion gel electrophoresis, and the restriction mapping of a cosmid clone, to construct a physical map of the murine T-cell receptor β-chain gene family. We have mapped 19 variable (Vβ) gene segments and the two clusters of diversity (Dβ) and joining (Jβ) gene segments and constant (Cβ) genes. These members of the β-chain gene family span ~450 kilobases of DNA, excluding one potential gap in the DNA fragment alignments

Generating Generalized Distributions from Dynamical Simulation

We present a general molecular-dynamics simulation scheme, based on the Nose' thermostat, for sampling according to arbitrary phase space distributions. We formulate numerical methods based on both Nose'-Hoover and Nose'-Poincare' thermostats for two specific classes of distributions; namely, those that are functions of the system Hamiltonian and those for which position and momentum are statistically independent. As an example, we propose a generalized variable temperature distribution that designed to accelerate sampling in molecular systems.Comment: 10 pages, 3 figure

Influence of Viewing Dramatic Television and Perceived Risk of Victimization on Crime-Specific Fear

The purpose of this study is to examine the predictability of the fear of property and personal crime in relation to viewing dramatic or violent television. The study was carried out using the viewpoint that the viewing of violence, which is symbolically communicated through the medium of television, does affect the fear of crime. A questionnaire was administered in the spring of 1998 to students of a mid-South regional university. The sample consisted of 619 undergraduate students. Descriptive statistics, bivariate correlations, and multiple regression were used to analyze the data. The results of this study suggest that watching violent television content influences the fear of personal crime. However, viewing this type of television seems to have a smaller impact on the fear of property crime

Generating generalized distributions from dynamical simulation

This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/118/13/10.1063/1.1557413.We present a general molecular-dynamics simulation scheme, based on the Nosé thermostat, for sampling from arbitrary phase space distributions. We formulate numerical methods based on both Nosé–Hoover and Nosé–Poincaré thermostats for two specific classes of distributions; namely, those that are functions of the system Hamiltonian and those for which position and momentum are statistically independent. As an example, we propose a generalized variable temperature distribution that is designed to accelerate sampling in molecular systems

Clock shift in a strongly interacting two-dimensional Fermi gas

We derive universal relations for the radio-frequency (rf) spectroscopy of a two-dimensional Fermi gas consisting of two spin states with a resonant S-wave interaction. The rf transition rate has a high-frequency tail that is proportional to the contact and displays logarithmic scaling violations, decreasing asymptotically like $1/(\omega^2 \ln^2 \omega)$. Its coefficient is proportional to $\ln^2(a_{2D}'/a_{2D})$, where $a_{2D}$ and $a_{2D}'$ are the 2-dimensional scattering lengths associated with initial-state and final-state interactions. The clock shift is proportional to the contact and to $\ln(a_{2D}'/a_{2D})$. If $|\ln(a_{2D}'/a_{2D})| \gg 1$, the clock shift arises as a cancellation between much larger contributions proportional to $\ln^2(a_{2D}'/a_{2D})$ from bound-bound and bound-free rf transitions.Comment: 4 pages, 1 figur

Spectropolarimetry and Modeling of the Eclipsing T Tauri Star KH 15D

KH 15D is a strongly variable T Tauri star in the young star cluster NGC 2264 that shows a decrease in flux of 3.5 magnitudes lasting for 18 days and repeating every 48 days. The eclipsing material is likely due to orbiting dust or rocky bodies in a partial ring or warped disk that periodically occults the star. We measured the polarized spectrum in and out of eclipse at the Keck and Palomar observatories. Outside of the eclipse, the star exhibited low polarization consistent with zero. During eclipse, the polarization increased dramatically to ~2% across the optical spectrum, while the spectrum had the same continuum shape as outside of eclipse and exhibited emission lines of much larger equivalent width, as previously seen. From the data, we conclude that (a) the scattering region is uneclipsed; (b) the scattering is nearly achromatic; (c) the star is likely completely eclipsed so that the flux during eclipse is entirely due to scattered light, a conclusion also argued for by the shape of the ingress and egress. We argue that the scattering is not due to electrons, but may be due to large dust grains of size ~10 micron, similar to the interplanetary grains which scatter the zodiacal light. We construct a warped-disk model with an extended dusty atmosphere which reproduces the main features of the lightcurve, namely (a) a gradual decrease before ingress due to extinction in the atmosphere (similar for egress); (b) a sharper decrease within ingress due to the optically-thick base of the atmosphere; (c) a polarized flux during eclipse which is 0.1% of the total flux outside of eclipse, which requires no fine-tuning of the model. (abridged)Comment: 9 pages, 7 figures, accepted for publication in ApJ, MPEG simulation available at http://www.astro.washington.edu/agol/scatter2.mp

Integrated TiO2 resonators for visible photonics

We demonstrate waveguide-coupled titanium dioxide (TiO2) racetrack resonators with loaded quality factors of 2x10^4 for the visible wavelengths. The structures were fabricated in sputtered TiO2 thin films on oxidized silicon substrates using standard top-down nanofabrication techniques, and passively probed in transmission measurements using a tunable red laser. Devices based on this material could serve as integrated optical elements as well as passive platforms for coupling to visible quantum emitters.Comment: 4 pages, 3 figure