6,275 research outputs found

    Electron spin-orbit splitting in InGaAs/InP quantum well studied by means of the weak antilocalization and spin-zero effects in tilted magnetic fields

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    The coupling between Zeeman spin splitting and Rashba spin-orbit terms has been studied experimentally in a gated InGaAs/InP quantum well structure by means of simultaneous measurements of the weak antilocalization (WAL) effect and beating in the SdH oscillations. The strength of the Zeeman splitting was regulated by tilting the magnetic field with the spin-zeros in the SdH oscillations, which are not always present, being enhanced by the tilt. In tilted fields the spin-orbit and Zeeman splittings are not additive, and a simple expression is given for the energy levels. The Rashba parameter and the electron g-factor were extracted from the position of the spin zeros in tilted fields. A good agreement is obtained for the spin-orbit coupling strength from the spin-zeros and weak antilocalization measurements.Comment: Accepted for publication in Semiconductors Science and Technolog

    Ascending aortic remodelling in Fabry disease after long-term enzyme replacement therapy.

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    Previous cross-sectional studies reported a high prevalence of ascending aorta dilations/aneurysms in male adults with Fabry disease, independently of cardiovascular risk factors. To characterise the remodelling of the ascending aorta in classic Fabry disease under long-term enzyme replacement therapy. Diameter of the ascending aorta was measured with magnetic resonance imaging at the sino-tubular junction (STJ), and proximal (pAsAo), and distal ascending aorta (dAsAo) at baseline, and after 5 and 10 years of enzyme replacement therapy in 15 adult Fabry patients (10 males; 5 females). Over a mean follow-up of 9.5 years, the annual expansion rates measured in 10 males with Fabry disease were 0.41 ± 0.16, 0.36 ± 0.25 and 0.41 ± 0.26 mm/y at the STJ, pAsAo and dAsAo, respectively. Expansion rate at the pAsAo level in male patients was significantly higher than the expected expansion projected from theoretical normal values: 0.36 ± 0.25 vs 0.13 ± 0.05, p = 0.017. In 5 females, the annual expansion rates at the STJ, pAsAo and dAsAo were 0.14 ± 0.11, 0.21 ± 0.18 and 0.26 ± 0.24 mm/y, respectively. There was no significant difference from the projected normal expansion rate at the level of the pAsAo: 0.21 ± 0.18 vs 0.13 ± 0.04, p = 0.39. Our data suggest that the remodelling of the ascending aorta is more pronounced in male patients with Fabry disease under long-term enzyme replacement therapy compared with the progression observed in a large population study

    Fitting Blazhko light curves

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    The correct amplitude and phase modulation formalism of the Blazhko modulation is given. The harmonic order dependent amplitude and phase modulation form is equivalent with the Fourier decomposition of multiplets. The amplitude and phase modulation formalism used in electronic transmission technique as introduced by Benk\H{o}, Szab\'o and Papar\'o (2011, MNRAS 417, 974) for Blazhko stars oversimplifies the amplitude and phase modulation functions thus it does not describe the light variation in full detail. The results of the different formalisms are compared and documented by fitting the light curve of a real Blazhko star, CM UMa.Comment: 8 pages, 5 figures. Accepted for publication in MNRA

    An extensive photometric study of the Blazhko RR Lyrae star RZ Lyr

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    The analysis of recent, extended multicolour CCD and archive photoelectric, photographic and visual observations has revealed several important properties of RZ Lyr, an RRab-type variable exhibiting large-amplitude Blazhko modulation. On the time-base of \sim110 yr, a strict anticorrelation between the pulsation and modulation period changes is established. The light curve of RZ Lyr shows a remarkable bump on the descending branch in the small-amplitude phase of the modulation, similarly to the light curves of bump Cepheids. We speculate that the stellar structure temporally suits a 4:1 resonance between the periods of the fundamental and one of the higher-order radial modes in this modulation phase. The light-curve variation of RZ Lyr can be correctly fitted with a two-modulation-component solution; the 121 d period of the main modulation is nearly but not exactly four times longer than the period of the secondary modulation component. Using the inverse photometric method, the variations in the pulsation-averaged values of the physical parameters in different phases of both modulation components are determined.Comment: 15 pages, 14 figures, 8 tables. Published in MNRAS, 2012. [v3]: Only change: title correcte
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