11,286 research outputs found

    Consequences of Approximate S3S_3 Symmetry of the Neutrino Mass Matrix

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    Assuming that the neutrino mass matrix is dominated by a term with the permutation symmetry S3S_{\scriptscriptstyle 3} it is possible to explain neutrino data only if the masses are quasi-degenerate. A sub-dominant term with an approximate μ−τ\mu -\tau symmetry leads to an approximate tri-bimaximal form. Experimental consequences are discussed.Comment: 7 pages, 2 figures, 1 table, RevTe

    GROWTH THEORY AND ACCOUNTING FOR GROWTH OF THE TAIWANESE ECONOMY

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    A growth accounting and an econometric exercise are used to provide insights into the evolution of the Taiwanese economy over the period 1966-96. The approach links the GDP function of a multiple sector neoclassical growth model to growth accounting and, subsequently to the estimation of the parameters of this function. The growth accounting results show that the contribution of total factor productivity (TFP) to growth in GDP averaged about 32 percent over the period, and this contribution increased as the economy approached its long-run equilibrium during the decade of the 1980s, with evidence of some departure during 1991-96. Growth in TFP increased output growth in industry and services while growth in skilled labor benefited all sectors. Growth in capital stock increased the growth of the industrial sector the most, followed by services, but the effect on agricultural output growth was negative. Growth in TFP and capital stock appear to have increased the capacity of the industrial and service sectors to pull resources from agriculture.economic growth, productivity, technological change, International Development, Productivity Analysis, O3, O4, O5,

    Control of tetrahedral coordination and superconductivity in FeSe0.5Te0.5 thin films

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    We demonstrate a close relationship between superconductivity and the dimensions of the Fe-Se(Te) tetrahedron in FeSe0.5Te0.5. This is done by exploiting thin film epitaxy, which provides controlled biaxial stress, both compressive and tensile, to distort the tetrahedron. The Se/Te height within the tetrahedron is found to be of crucial importance to superconductivity, in agreement with the theoretical proposal that (pi,pi) spin fluctuations promote superconductivity in Fe superconductors

    Electro-optic resonant phase modulator

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    An electro-optic resonant cavity is used to achieve phase modulation with lower driving voltages. Laser damage thresholds are inherently higher than with previously used integrated optics due to the utilization of bulk optics. Phase modulation is achieved at higher speeds with lower driving voltages than previously obtained with non-resonant electro-optic phase modulators. The instant scheme uses a data locking dither approach as opposed to the conventional sinusoidal locking schemes. In accordance with a disclosed embodiment, a resonant cavity modulator has been designed to operate at a data rate in excess of 100 megabits per sec. By carefully choosing the cavity finesse and its dimension, it is possible to control the pulse switching time to within 4 nano-sec. and to limit the required switching voltage to within 10 V. This cavity locking scheme can be applied by using only the random data sequence, and without the need of dithering of the cavity. Compared to waveguide modulators, the resonant cavity has a comparable modulating voltage requirement. Because of its bulk geometry, the resonant cavity modulator has the potential of accommodating higher throughput power. Mode matching into the bulk device is easier and typically can be achieved with higher efficiency. An additional control loop is incorporated into the modulator to maintain the cavity on resonance

    Optical Coherence Tomography Angiography Features of Iris Racemose Hemangioma in 4 Cases.

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    Importance: Optical coherence tomography angiography (OCTA) allows visualization of iris racemose hemangioma course and its relation to the normal iris microvasculature. Objective: To describe OCTA features of iris racemose hemangioma. Design, Setting, and Participants: Descriptive, noncomparative case series at a tertiary referral center (Ocular Oncology Service of Wills Eye Hospital). Patients diagnosed with unilateral iris racemose hemangioma were included in the study. Main Outcomes and Measures: Features of iris racemose hemangioma on OCTA. Results: Four eyes of 4 patients with unilateral iris racemose hemangioma were included in the study. Mean patient age was 50 years, all patients were white, and Snellen visual acuity was 20/20 in each case. All eyes had sectoral iris racemose hemangioma without associated iris or ciliary body solid tumor on clinical examination and ultrasound biomicroscopy. By anterior segment OCT, the racemose hemangioma was partially visualized in all cases. By OCTA, the hemangioma was clearly visualized as a uniform large-caliber vascular tortuous loop with intense flow characteristics superimposed over small-caliber radial iris vessels against a background of low-signal iris stroma. The vascular course on OCTA resembled a light bulb filament (filament sign), arising from the peripheral iris (base of light bulb) and forming a tortuous loop on reaching its peak (midfilament) near the pupil (n = 3) or midzonal iris (n = 1), before returning to the peripheral iris (base of light bulb). Intravenous fluorescein angiography performed in 1 eye depicted the iris hemangioma; however, small-caliber radial iris vessels were more distinct on OCTA than intravenous fluorescein angiography. Conclusions and Relevance: Optical coherence tomography angiography is a noninvasive vascular imaging modality that clearly depicts the looping course of iris racemose hemangioma. Optical coherence tomography angiography depicted fine details of radial iris vessels, not distinct on intravenous fluorescein angiography

    Manual for extending the laser specklegram technique to strain analysis of rotating components

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    The theory, techniques, and equipment necessary for extending laser speckle techniques to analyze stresses in rotating blades are described. Details for setting up the equipment, for timing the events, for data recording, and for data analysis are discussed. Finite element techniques are investigated for analysis of speckle data. Advantages and limitations of the finite element analysis for the speckle data are discussed. The finite element program is listed
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