42,566 research outputs found

    What kinds of coordinate can keep the Hawking temperature invariant for the static spherically symmetric black hole?

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    By studying the Hawking radiation of the most general static spherically symmetric black hole arising from scalar and Dirac particles tunnelling, we find the Hawking temperature is invariant in the general coordinate representation (\ref{arbitrary1}), which satisfies two conditions: a) its radial coordinate transformation is regular at the event horizon; and b) there is a time-like Killing vector.Comment: 10 page

    Pharmacokinetics of recombinant human erythropoietin applied subcutaneously to children with chronic renal failure

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    The single-dose pharmacokinetics of recombinant human erythropoietin (rHuEPO) given SC was investigated in 20 patients aged 7-20 years at different stages of chronic renal failure. In a pilot study we confirmed the lower bioavailability of the drug in 2 children when given SC compared with the IV route (24% and 43%, respectively). Following administration of 4,000 units/m2, rHuEPO SC effective serum erythropoietin concentrations increased from a mean baseline level (+/- SD) of 23 +/- 13 units/l to a mean peak concentration of 265 +/- 123 units/l, which was reached after 14.3 +/- 9.4 h, followed by a slow decline until baseline values were attained at 72 h. Mean residence time was 30 +/- 9 h and mean elimination half-time 14.3 +/- 7 h. The single-dose kinetics of SC rHuEPO in children with different degrees of renal failure are comparable to those in adult patients. Possibly, the higher efficacy of SC rHuEPO in patients with renal anaemia compared with IV rHuEPO is related to its prolonged action

    Quantum Criticality and Inhomogeneous Magnetic Order in Fe-doped alpha-YbAlB4

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    The intermediate-valent polymorphs α\alpha- and β\beta-YbAlB4_4 exhibit quantum criticality and other novel properties not usually associated with intermediate valence. Iron doping induces quantum criticality in α\alpha-YbAlB4_4 and magnetic order in both compounds. We report results of muon spin relaxation (μ\muSR) experiments in the intermediate-valent alloys α\alpha-YbAl1x_{1-x}Fex_xB4_4, x=0.014x = 0.014 and 0.25. For x=0.014x = 0.014 we find no evidence for magnetic order down to 25 mK\@. The dynamic muon spin relaxation rate λd\lambda_d exhibits a power-law temperature dependence λdTa\lambda_d \propto T^{-a}, a=0.40(4)a = 0.40(4), in the temperature range 100 mK--2 K, in disagreement with predictions by theories of antiferromagnetic (AFM) or valence quantum critical behavior. For x=0.25x = 0.25, where AFM order develops in the temperature range 7.5--10 K, where we find coexistence of meso- or macroscopically segregated paramagnetic and AFM phases, with considerable disorder in the latter down to 2 K.Comment: 9 pages, 10 figures, to be published in Phys. Rev.

    Predicting and understanding spatio-temporal dynamics of species recovery : implications for Asian crested ibis Nipponia nippon conservation in China

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    Acknowledgements This work was supported by the National Natural Science Foundation of China (No. 31372218) and cofunded by the China Scholarship Council (CSC) and the ITC Research Fund, Enschede, the Netherlands. We thank Shaanxi Hanzhong Crested Ibis National Nature Reserve for sharing the data of nest site locations. We are grateful to Brendan Wintle, Justin Travis and two anonymous reviewers for helpful comments on a previous version of the manuscript.Peer reviewedPublisher PD

    Superconducting gap symmetry of Ba0.6K0.4Fe2As2 studied by angle-resolved photoemission spectroscopy

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    We have performed high-resolution angle-resolved photoemission spectroscopy on the optimally-doped Ba0.6_{0.6}K0.4_{0.4}Fe2_2As2_2 compound and determined the accurate momentum dependence of the superconducting (SC) gap in four Fermi-surface sheets including a newly discovered outer electron pocket at the M point. The SC gap on this pocket is nearly isotropic and its magnitude is comparable (Δ\Delta \sim 11 meV) to that of the inner electron and hole pockets (\sim12 meV), although it is substantially larger than that of the outer hole pocket (\sim6 meV). The Fermi-surface dependence of the SC gap value is basically consistent with Δ\Delta(kk) = Δ\Delta0_0coskxk_xcoskyk_y formula expected for the extended s-wave symmetry. The observed finite deviation from the simple formula suggests the importance of multi-orbital effects.Comment: 4 pages, 3 figures, 1 tabl

    Magnetoresistance in the s-d Model with Arbitrary Impurity Spin

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    The magnetoresistance, the number of the localized electrons, and the s-wave scattering phase shift at the Fermi level for the s-d model with arbitrary impurity spin are obtained in the ground state. To obtain above results some known exact results of the Bethe ansatz method are used. As the impurity spin S = 1/2, our results coincide with those obtained by Ishii \textit{et al%}. The compairsion between the theoretical and experimental magneticresistence for impurity S = 1/2 is re-examined.Comment: 6 pages, 2 figure

    Spectroscopy of 87Sr^{87}\text{Sr} triplet Rydberg states

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    A combined experimental and theoretical spectroscopic study of high-nn, 30n100{30 \lesssim n \lesssim 100}, triplet S\text{S} and D\text{D} Rydberg states in 87Sr^{87}\text{Sr} is presented. 87Sr^{87}\text{Sr} has a large nuclear spin, I=9/2{I=9/2}, and at high-nn the hyperfine interaction becomes comparable to, or even larger than, the fine structure and singlet-triplet splittings which poses a considerable challenge both for precision spectroscopy and for theory. For high-nn S\text{S} states, the hyperfine shifts are evaluated non-perturbatively taking advantage of earlier spectroscopic data for the I=0{I=0} isotope 88Sr^{88}\text{Sr}, which results in good agreement with the present measurements. For the D\text{D} states, this procedure is reversed by first extracting from the present 87Sr^{87}\text{Sr} measurements the energies of the 3D1,2,3^{3}\text{D}_{1,2,3} states to be expected for isotopes without hyperfine structure (88Sr^{88}\text{Sr}) which allows the determination of corrected quantum defects in the high-nn limit.Comment: 13 pages, 8 figure

    Nonlinear phenomena of the buck-boost converter analyzed by storage energy

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    Author name used in this publication: K. W. E. ChengAuthor name used in this publication: Z. H. ShiAuthor name used in this publication: K. DingVersion of RecordPublishe
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