3,279 research outputs found

    Catalog of data summary of airglow observations obtained at Haleakala, Hawaii

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    The airglow studies were initiated in July 1961 in response to the discovery of unusual phenomena in the tropical airglow as observed from Algeria. Hawaii, being the southern-most area in the United States and within the tropics, and possessing high mountains with frequent clear skies well isolated from the contaminating light and dust of civilization, appeared to be an ideal location for establishing a tropical airglow station. The University of Hawaii was already developing the Mees Solar Laboratory on Haleakala on the island of Maui, so that the addition of a night sky observatory was a natural development. The collection of data covers a span of about seven and one-half years, including the minimum of the solar cycle in 1963 and just getting into the next maximum in 1968-69. It was unfortunate that financial limitations did not permit the continuation of the observations through one complete solar cycle

    F-region nightglow emissions of atomic oxygen. II - Analysis of 6300 angstrom and electron density data

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    F-region nightglow emissions of atomic oxygen - analysis of 6300 angstrom and electron density dat

    Quantum-kinetic theory of photocurrent generation via direct and phonon-mediated optical transitions

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    A quantum-kinetic theory of direct and phonon mediated indirect optical transitions is developed within the framework of the non-equilibrium Green's function formalism. After validation against the standard Fermi-Golden-Rule approach in the bulk case, it is used in the simulation of photocurrent generation in ultra-thin crystalline silicon p-i-n-junction devices.Comment: 12 pages, 11 figure

    Atlas of zenith airglow plots obtained at Haleakala, Hawaii. Volume 1: July 1961 to December 1964

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    This Atlas presents zenith airglow intensities as a function of time as observed from Haleakala, Hawaii

    One dimensional chain of quantum molecule motors as a mathematical physics model for muscle fibre

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    A quantum chain model of many molecule motors is proposed as a mathematical physics theory on the microscopic modeling of classical force-velocity relation and tension transients of muscle fibre. We proposed quantum many-particle Hamiltonian to predict the force-velocity relation for the slow release of muscle fibre which has no empirical relation yet, it is much more complicate than hyperbolic relation. Using the same Hamiltonian, we predicted the mathematical force-velocity relation when the muscle is stimulated by alternative electric current. The discrepancy between input electric frequency and the muscle oscillation frequency has a physical understanding by Doppler effect in this quantum chain model. Further more, we apply quantum physics phenomena to explore the tension time course of cardiac muscle and insect flight muscle. Most of the experimental tension transients curves found their correspondence in the theoretical output of quantum two-level and three-level model. Mathematically modeling electric stimulus as photons exciting a quantum three-level particle reproduced most tension transient curves of water bug Lethocerus Maximus.Comment: 16 pages, 12 figures, Arguments are adde

    Characterization of wear debris released from alumina-on-alumina hip prostheses: Analysis of retrieved femoral heads and peri-prosthetic tissues

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    We analyzed by SEM three alumina-on-alumina femoral heads obtained from three patients who underwent revision for an aseptic loosening of the acetabular component. In parallel, the peri-prosthetic tissues were analyzed histologically in search of wear debris coming from the ceramic. Stripe wears, abrasive streaks, craters, and areas with extensive biomaterial removal were evidenced on the three femoral heads by SEM. In the altered area, the structure of the ceramic composed of minute polyhedric grains packed together was evidenced. In the peri-prosthetic tissues, the alumina particles were present in different forms: larges particles appeared transparent and birefringent, small particles engulfed by the macrophages had a light brown tint and were not birefringent. Large particles corresponded to the grains observed by SEM. EDS microanalysis confirmed the presence of aluminum oxide in these particles. Alumina debris are difficult to identify microscopically due to their pleomorphism

    Coronal Emission Measures and Abundances for Moderately Active K Dwarfs Observed by Chandra

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    We have used Chandra to resolve the nearby 70 Oph (K0 V+K5 V) and 36 Oph (K1 V+K1 V) binary systems for the first time in X-rays. The LETG/HRC-S spectra of all four of these stars are presented and compared with an archival LETG spectrum of another moderately active K dwarf, Epsilon Eri. Coronal densities are estimated from O VII line ratios and emission measure distributions are computed for all five of these stars. We see no substantial differences in coronal density or temperature among these stars, which is not surprising considering that they are all early K dwarfs with similar activity levels. However, we do see significant differences in coronal abundance patterns. Coronal abundance anomalies are generally associated with the first ionization potential (FIP) of the elements. On the Sun, low-FIP elements are enhanced in the corona relative to high-FIP elements, the so-called "FIP effect." Different levels of FIP effect are seen for our stellar sample, ranging from 70 Oph A, which shows a prominent solar-like FIP effect, to 70 Oph B, which has no FIP bias at all or possibly even a weak inverse FIP effect. The strong abundance difference exhibited by the two 70 Oph stars is unexpected considering how similar these stars are in all other respects (spectral type, age, rotation period, X-ray flux). It will be difficult for any theoretical explanation for the FIP effect to explain how two stars so similar in all other respects can have coronae with different degrees of FIP bias. Finally, for the stars in our sample exhibiting a FIP effect, a curious difference from the solar version of the phenomenon is that the data seem to be more consistent with the high-FIP elements being depleted in the corona rather than a with a low-FIP enhancementComment: 35 pages, 8 figures, AASTEX v5.0 plus EPSF extensions in mkfig.sty; accepted by Ap

    Clinical and radiological outcomes of a cohort of 9 patients with anatomical fractures of the cuboid treated by locking plate fixation

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    INTRODUCTION: Cuboid fractures are very rare. Hence, their treatment has not been standardized. Advances in imaging techniques, particularly three-dimensional computed tomography (3D CT), and the introduction of cuboid-specific plates has improved the care of these injuries. The aim of this study was to determine the radiological and clinical outcomes of anatomical reconstruction of comminuted cuboid fractures with a locking plate. HYPOTHESIS: Fixation of comminuted cuboid fractures with a cuboid-specific locking plate leads to stable anatomical reduction and good functional outcomes. MATERIAL AND METHODS: This was a retrospective study of 9 consecutive cases of comminuted cuboid fracture treated at a single hospital between January 2009 and December 2015. A 3D CT scan was performed preoperatively with subtraction of the posterior tarsal bone to allow the articular facets to be viewed and analyzed. Fracture fixation was done with a Locking Cuboid Plate (DePuy Synthes™). Associated lesions in the foot were treated during the same procedure. The patients were reviewed by an independent observer who performed a clinical examination, and determined the AOFAS and Maryland Foot Score. The success of the reconstruction was determined by comparing the parameters on weight-bearing X-rays views between the fixed and non-operated cuboid. RESULTS: The mean follow-up was 4.1 years (range 1-6). The Maryland Foot Score was 93.1 [86-100] and the AOFAS was 91.9 [82-100]. The reconstruction was anatomical and long lasting in all 9 cases. There was no foot misalignment in the frontal plane, based on the radiographs (hindfoot axis 5.5° [0-9]). The mean Djian-Annonier angle was 123.9° [108-130]. CONCLUSION: Cuboid fractures can be treated effectively through appropriate imaging and with a cuboid-specific locking plate as evidenced by very good midterm clinical and radiological outcomes in this study. LEVEL OF EVIDENCE: IV Retrospective study

    Characterization of the TruSense S310 Laser Range System for Contact-less Measurement of Liquid Levels in Large-Volume Neutrino Detectors

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    Neutrino experiments often use large volumes of water, organic scintillators or noble liquids as active detection material. Due to the large hydrostatic and buoyancy forces involved, precise knowledge of the liquid levels inside the detector tank are mandatory. Here we present the main characteristics of the TruSense S310 Laser Range System. Level measurements can be performed without direct contact to the liquid and through a gas-proof acrylic window, thus preserving the strict radiopurity and chemical requirements of the target liquid. We report the results of a suit of laboratory experiments for short-term precision tests (±\pm5\,mm) and long-term stability studies. Moreover, we demonstrate that the infrared laser can be used while standard bi-alkali PMTs are operational. We discuss the mechanical layout and integration of the system in the OSIRIS pre-detector that will monitor the radiopurity of the liquid scintillator for the large-volume neutrino experiment JUNO
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