A fast-neutron spectrometer of advanced design

Fast neutron spectrometer combines helium filled proportional counters with solid-state detectors to achieve the properties of high efficiency, good resolution, rapid response, and effective gamma ray rejection

A high resolution investigation of vacuum ultraviolet wavelength standards

Imperial Users onl

Effects of surface crossing in chemical reactions - The H3/plus/ system

Potential energy surfaces for singlet states of H3/plus

Light-cone coordinates based at a geodesic world line

Continuing work initiated in an earlier publication [Phys. Rev. D 69, 084007 (2004)], we construct a system of light-cone coordinates based at a geodesic world line of an arbitrary curved spacetime. The construction involves (i) an advanced-time or a retarded-time coordinate that labels past or future light cones centered on the world line, (ii) a radial coordinate that is an affine parameter on the null generators of these light cones, and (iii) angular coordinates that are constant on each generator. The spacetime metric is calculated in the light-cone coordinates, and it is expressed as an expansion in powers of the radial coordinate in terms of the irreducible components of the Riemann tensor evaluated on the world line. The formalism is illustrated in two simple applications, the first involving a comoving world line of a spatially-flat cosmology, the other featuring an observer placed on the axis of symmetry of Melvin's magnetic universe.Comment: 11 pages, 1 figur

The Venus Balloon Project

On June 11 and 15, 1985, two instrumental balloons were released from the Soviet VEGA 1 and VEGA 2 spacecraft and deployed in the atmosphere of Venus. The VEGA probes flew by the planet on their way to a rendezvous with comet Halley in March 1986. Drifting with the wind at altitudes of 54 km, the balloons traveled one-third of the way around the planet during their 46-hour lifetimes. Sensors on-board the gondolas made periodic measurements of pressure, temperature, vertical wind velocity, cloud particle density, ambient light level, and frequency of lightning. The data were transmitted to Earth and received at the Deep Space Network (DSN) 64-m stations and at several large antennas in the USSR. Approximately 95 percent of the telemetry data were successfully decoded at the DSN complexes and in the Soviet Union, and were provided to the international science team for analysis. Very Long Baseline Interferometry (VLBI) data were acquired by 20 radio observatories around the world for the purpose of monitoring the Venus winds. The DSN 64-m subnet was part of a 15-station VLBI network organized by the Centre National d'Etudes Spatiales (CNES) of France. In addition, five antennas of the Soviet network participated. VLBI data from the CNES network are currently being processed at the Jet Propulsion Laboratory

Searching for low mass objects around nearby dMe radio stars

Nearby M-dwarfs are best suited for searches of low mass companions. VLBI phase-referencing observations with sensitive telescopes are able to detect radio star flux-densities of tenths of mJy as well as to position the star on the sky with submilliarcsecond precision. We have initiated a long-term observational program, using EVN telescopes in combination with NASA DSN dishes, to revisit the kinematics of nearby, single M dwarfs. The precision of the astrometry allows us to search for possible companions with masses down to 1 Jupiter mass. In this contribution we report preliminary results of the first observation epochs, in which we could detect some of the radio stars included in our program.Comment: Proceedings of the 6th European VLBI Network Symposium, Ros E., Porcas R.W., Lobanov A.P., & Zensus J.A. (eds.), MPIfR, Bonn, Germany, p. 255-258 (2002). 4 pages, 3 figures, needs evn2002.cl

Are dietary fish oil supplements appropriate for dyslipidemia management? A review of the evidence

PURPOSE OF REVIEW: The purpose of this review is to assess whether dietary fish oil supplements can be appropriate for patients with elevated triglycerides and cardiovascular risk based on a comprehensive analysis of their composition, and level of regulatory oversight. RECENT FINDINGS: Approximately 19 million people in the United States take fish oil supplements, many for the purpose of treating or preventing heart disease. Unlike prescription products, fish oil supplements are classified as food by the Food and Drug Administration (FDA) and are not required to undergo manufacturing oversight or clinical testing. Analysis of widely used dietary fish oil supplements show that they may have lower amounts of omega-3 than advertised as well as significant levels of saturated fat and oxidized oils which actually may contribute to dyslipidemia. Clinical outcome trials have failed to show a consistent cardiovascular benefit with fish oil supplements and other low-dose mixed omega-3 fatty acids. SUMMARY: In light of limited regulatory oversight and evidence of quality concerns, dietary fish oil supplements are not an appropriate substitute for FDA approved prescription omega-3 fatty acids for their indicated use in treatment of elevated triglycerides or the prevention of cardiovascular events

Theoretical Predictors of Delinquency In and Out of School Among a Sample of Rural Public School Youth

This paper compares predictors of in-school and out-of-school delinquency and is based on data collected from 2,011 subjects at two elementary, one middle, and one high school in a rural school district. Predictors were derived from a variety of theoretical perspectives including social organization and social control; interactionist theory; differential association and social learning; strain, culture conflict, and critical theory. In addition, several demographic variables were included in the analysis. Regression results revealed that negative peer influence, victimization experience, attachment to school, gender, general strain, alienation, and the student’s self-reported response to a weapon at school were significant predictors of delinquency both in and out of school. Moreover, the relative contribution of each predictor in explaining delinquency was similar in the in-school and outside-school models. The paper concludes with a discussion of the policy implications of these findings for the schools studied

Intravitreal Aflibercept Outcomes in Patients with Persistent Macular Exudate Previously Treated with Bevacizumab and/or Ranibizumab for Neovascular Age-Related Macular Degeneration

Purpose. To assess whether intravitreal aflibercept (2.0mg) can effectively reduce persistent macular exudate and enhance visual acuity in ranibizumab (0.5mg) and/or bevacizumab (1.25 mg) treatment resistant patients with neovascular age-related macular degeneration. Methods. This retrospective study included 47 treatment resistant eyes from 47 patients switched to intravitreal aflibercept injections after receiving a minimum of 3 injections with either ranibizumab or bevacizumab. Snellen visual acuity and optical coherence tomography were assessed just prior to the first injection (baseline) and prior to the fourth injection (final). Additionally, anatomical regions of persistent macular exudate were tracked to determine if these areas yielded varying responses to aflibercept. Results. At baseline, patients had received an average of 11.3 injections with any prior anti-VEGF drug (SD 5.96). For whole group analysis, baseline and final central retinal thickness were 370.57 mu m and 295.7 mu m (P \u3c =.001), respectively. Baseline and final retinal fluid volumes were 4.81 mm(3) and 4.37 mm(3) (P \u3c =.001), respectively. Baseline and final logMAR were 0.56 and 0.53 (P = 0.301), respectively. Anatomic location of persistent exudate did not appreciably alter treatment outcome. Conclusion. Central retinal thickness and total retinal fluid volume were reduced in ranibizumab and/or bevacizumab treatment resistant patients following three aflibercept injections. No appreciable change in visual acuity was noted