Moored acoustic travel time (ATT) current meters : evolution, performance, and future designs

New laboratory measurements and numeric model studies show the present folded-path ATT current meters are stable and sensitive, but are not well suited for mean flow observations in surface gravity waves. Alternate designs which reduce unwanted wake effects are proposed. ATT flowmeter history, principles of acoustic flow sensors, mean flow near cylinders, and the need for linear flow sensors are reviewed.Prepared for the Office of Naval Research under Contract Number N00014-76-C-0197; NR083-400 to the Woods Hole Oceanographic Institution

Efficacy of Reusing NanoDot OSL Dosimeters Using Optical Bleaching

Use of optically stimulated luminescence detectors (OSLDs) is rapidly increasing in the area of in vivo dosimetry. OSLDs are relatively new to the market compared to their main competitor, thermoluminescent detectors (TLDs). Currently, not all characteristics of OSLDs have been fully investigated. Landauer’s nanoDot OSLDs were used in conjunction with their MicroStar reader to ascertain a nanoDot's ability to be reused. Annealing an OSLD signal with heat has been documented to work well. Due to the plastic casing on nanoDots, the high heat needed for annealing would destroy the OSLD. For this reason, nanoDots need to be bleached with light if they are to be reused. The strength of the light used was investigated by comparing the effects of bleaching with 15 W and 25 W lights. OSLDs use light to read out the signal, so each reading depletes some fraction of the signal. The rate of depletion per reading was looked at and compared to other data (Jursinic 2007). Most importantly, the effects of accumulated dose on the sensitivity of OSLDs were explored. This was done at different accumulated dose rates. Differences between the two wattages of light were found to play a minimal role on the total time needed for ample bleaching. The loss of signal per reading of the nanoDot was determined to be 0.04% per readout, which closely agrees with the Jursinic paper (2007). The sensitivity of the chip was shown to be stable up to 1080 cGy of accumulated dose. After this threshold point, the sensitivity of the OSLD decreases at a rate of 0.00456 cGy lost per cGy accumulated above 1080. This can be used to make a correction that can be added to the dose read out in nanoDots with accumulated doses above 1080 cGy. The use of the correction relies on the assumption that different OSLDs behave similarly under different accumulated dose rates and that differences in manufacturing between nanoDots are small enough to be negligible

Trait Sensitivity, Anxiety and Personality are predictive of Central Sensitisation Symptoms in Patients with Chronic Low Back Pain.

BACKGROUND:Sensitivity-related trait characteristics involving physical and emotional sensitivities and high trait anxiety personality types have been observed in individuals with non-specific chronic low back pain (NSCLBP). High trait sensitivity to sensory stimulation combined with interpretation biases based on personality type may contribute to the development of central sensitisation (CS) symptoms. To date there is limited research that has considered both sensitivity levels and personality type in NSCLBP with CS. The purpose of this study was to investigate 1) relationships between trait sensory profiles, trait anxiety and CS symptoms, and 2) the predictive capacity of sensory profiles, trait anxiety and personality types on CS symptoms, in people with NSCLBP. METHODS:This was a cross-sectional observational study using four self-report measures on adults (N = 165, mean age = 45 +-12 SD) from physiotherapy clinics in England, Ireland and New Zealand. Inclusion: NSCLBP > 6 months, aged 18-64, predominant CS pain presentation, no other pathology. Parametric and non-parametric correlation statistics and regression analyses were used. RESULTS:Positive correlations were found between central sensitisation inventory (CSI) scores and sensory hyper-sensitivity profiles and trait anxiety. CSI score increases could be predicted by: Sensory Sensitive, Low Registration profiles, trait anxiety scores and extreme defensive high anxious personality type. CONCLUSIONS:Trait sensory hyper- and/or hypo-sensitivity and high trait-anxiety related personality type characteristics predicts the extent of CS symptoms in people with NSCLBP. Further investigation is required to establish causality between these characteristics and CS symptoms. This article is protected by copyright. All rights reserved

Rim walkers and watchdogs : the metaphysical dialectics of John Gardner's fiction

John Gardner writes a fiction of ideas. The expression of metaphysical problems and the exploration of possible solutions dominate the thoughts of the characters and influence their decisions about action. Philosophical questions form the structure of the fiction since Gardner organizes his novels around a dialectical opposition of ontological, epistemological, and ethical stances. The characters tend to experience reality either as ordinary or as extraordinary; they know what is real either by categorization or by immediate intuition; and they act according to either an ethic which is based on the established cultural cannon of values or an ethic which is based on the immediate perception of a particular situation. Rim walkers and watchdogs represent these opposing philosophical stances. The rim walker of the fictions sees himself trapped in a universe beyond understanding, filled with mystery, in which "there are no stable principles." He advocates absolute freedom and action according to the intuitive grasp of what the universe demands at any moment. Watchdogs believe there is a stable system by which reality operates. They uphold the old value structures against time's constant decay and the anarchical, mysterious forces of existence. Since metaphysics takes cognizance of what might be called the deep structure of reality, fiction which presents characters emotionally as well as intellectually grappling with their experiences in terms of their perception of reality demands that the author go beyond an ordinary rendering of experience. Gardner draws on the tradition of the romance and on a special system of imagery to lift his fiction to the level of the extraordinary in order to suggest truths ordinarily out of reach.English, Department o

Basisonderzoek Aardgasverbruik Kleinverbruikers 1997

Dit artikel presenteert de cijfers van het 19e Basisonderzoek Aardgas Kleinverbruikers (BAK).