5,599 research outputs found

    Best constants in inequalities related to Opial's inequality

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    Spectra of convolution operators

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    The spectrum of the CesĂĄro operator

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    Presbyterian Imitation Practices in Zachary Boyd’s Nebuchadnezzars Fierie Furnace

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    The university administrator, preacher and poet Zachary Boyd (1585–1653) relied heavily on epithets and similes borrowed from Josuah Sylvester's poetry when composing his scriptural versifications Zion's Flowers(c. 1640?). The composition of Boyd's adaptation of Daniel 3, Nebuchadnezzars Fierie Furnace, provides an unusually lucid example of the reading and imitation practices of a mid-seventeenth-century Scottish Presbyterian in the years preceding civil war. This article begins by re-considering a manuscript transcription of Fierie Furnace held at the British Library previously described as an anonymous playtext from the early 1610s, then establishes the nature of Boyd's reliance on Sylvester by analyzing holograph manuscripts held at Glasgow University Library, a sermon Boyd wrote on the same theme, and the copy of Sylvester's Devine Weekes, and Workes that Boyd probably used.Arts and Humanities Research Counci

    Slow light with integrated gain and large pulse delay

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    We demonstrate slow and stored light in Rb vapor with a combination of desirable features: minimal loss and distortion of the pulse shape, and large fractional delay (> 10). This behavior is enabled by: (i) a group index that can be controllably varied during light pulse propagation; and (ii) controllable gain integrated into the medium to compensate for pulse loss. Any medium with the above two characteristics should be able to realize similarly high-performance slow light.Comment: 5 pages, 4 figures; abstract is shortened, some typo correcte

    Quantum channels in nonlinear optical processes

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    Quantum electrodynamics furnishes a new type of representation for the characterisation of nonlinear optical processes. The treatment elicits the detailed role and interplay of specific quantum channels, information that is not afforded by other methods. Following an illustrative application to the case of Rayleigh scattering, the method is applied to second and third harmonic generation. Derivations are given of parameters that quantify the various quantum channels and their interferences; the results are illustrated graphically. With given examples, it is shown in some systems that optical nonlinearity owes its origin to an isolated channel, or a small group of channels. © 2009 World Scientific Publishing Company

    Monotone Subsequences in the Sequence of Fractional Parts of Multiples of an Irrational

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    Hammersley [7] showed that if X1, X2, . . . is a sequence of independent identically distributed random variables whose common distribution is continuous, and if ln+(ln-) denotes the length of the longest increasing (decreasing) subsequence of X1, X2, . . ., Xn, then there is a constant c such that ln-⁄nœ→ c and ln+⁄nœ→ c in probability, as n → ∞. Kesten [8] showed that in fact there is almost sure convergence. Logan and Shepp [11] proved that c ≧ 2, and recently Versik and Kerov [13] have announced that c = 2

    State of Harmonization of 24 Serum Albumin Measurement Procedures and Implications for Medical Decisions

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    BACKGROUND: Measurements of serum and plasma albumin are widely used in medicine, including as indicators of quality of patient care in renal dialysis centers. METHODS: Pools were prepared from residual patient serum (n = 50) and heparin plasma (n = 48) from patients without renal disease, and serum from patients with kidney failure before hemodialysis (n = 53). Albumin was measured in all samples and in ERM-DA470k/IFCC reference material (RM) by 3 immunochemical, 9 bromcresol green (BCG), and 12 bromcresol purple (BCP) methods. RESULTS: Two of 3 immunochemical procedures, 5 of 9 BCG, and 10 of 12 BCP methods recovered the RM value within its uncertainty. One immunochemical and 3 BCG methods were biased vs the RM value. Random error components were small for all measurement procedures. The Tina-quant immunochemical method was chosen as the reference measurement procedure based on recovery and results of error analyses. Mean biases for BCG vs Tina-quant were 1.5% to 13.9% and were larger at lower albumin concentrations. BCP methods\u27 mean biases were -5.4% to 1.2% irrespective of albumin concentration. Biases for plasma samples were generally higher than for serum samples for all method types. For most measurement procedures, biases were lower for serum from patients on hemodialysis vs patients without kidney disease. CONCLUSIONS: Significant differences among immunochemical, BCG, and BCP methods compromise interpretation of serum. albumin results. Guidelines and calculations for clinical management of kidney and other diseases must consider the method used for albumin measurement until harmonization can be achieved
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