7,453 research outputs found

    Some Intensity Measurements in the Vacuum Ultraviolet

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    Intensity measurements in vacuum ultraviolet - photoelectric yields of untreated metals and semiconductors measured by calibrated thermocoupl

    Magnetization process in a chiral p-wave superconductor with multi-domains

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    A simulation study for the magnetization process is performed for the multi-domain state in a chiral p-wave superconductor, using the time-dependent Ginzburg-Landau theory. The external field penetrates inside as core-less vortices through the domain wall, forming the vortex sheet structure. We find that, with increasing magnetic fields, the domain walls move so that the unstable domains shrink to vanish. Therefore, the single domain structure is realized at higher fields

    Flux flow and pinning of the vortex sheet structure in a two-component superconductor

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    A simulation study using the time-dependent Ginzburg-Landau theory is performed for the vortex state in two-component superconductors, such as PrOs_4_Sb_12_. We investigate the flux flow and the pinning of the vortex sheet structure. We find domain wall that traps half flux-quantum vortices and moves with the flux flow. In the pinning case, we observe an emitting process of a conventional vortex from the vortex sheet by combining a pair of half flux-quantum vortices.Comment: 4 pages, 4 figures, to appear in Phys. Rev.

    Photoionization yield and absorption coeffi- cient of xenon in the region 860-1022 deg angstrom

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    Photoionization yield and absorption coefficient of xenon gas measured by photoelectric method

    On the distance of the Magellanic Clouds using Cepheid NIR and optical-NIR Period Wesenheit Relations

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    We present the largest near-infrared (NIR) data sets, JHKsJHKs, ever collected for classical Cepheids in the Magellanic Clouds (MCs). We selected fundamental (FU) and first overtone (FO) pulsators, and found 4150 (2571 FU, 1579 FO) Cepheids for Small Magellanic Cloud (SMC) and 3042 (1840 FU, 1202 FO) for Large Magellanic Cloud (LMC). Current sample is 2--3 times larger than any sample used in previous investigations with NIR photometry. We also discuss optical VIVI photometry from OGLE-III. NIR and optical--NIR Period-Wesenheit (PW) relations are linear over the entire period range (0.0<logPFU1.650.0<\log P_{\rm FU} \le1.65 ) and their slopes are, within the intrinsic dispersions, common between the MCs. These are consistent with recent results from pulsation models and observations suggesting that the PW relations are minimally affected by the metal content. The new FU and FO PW relations were calibrated using a sample of Galactic Cepheids with distances based on trigonometric parallaxes and Cepheid pulsation models. By using FU Cepheids we found a true distance moduli of 18.45±0.02(random)±0.10(systematic)18.45\pm0.02{\rm(random)}\pm0.10{\rm(systematic)} mag (LMC) and 18.93±0.02(random)±0.10(systematic)18.93\pm0.02{\rm(random)}\pm0.10{\rm(systematic)} mag (SMC). These estimates are the weighted mean over ten PW relations and the systematic errors account for uncertainties in the zero-point and in the reddening law. We found similar distances using FO Cepheids (18.60±0.03(random)±0.10(systematic)18.60\pm0.03{\rm(random)}\pm0.10{\rm(systematic)} mag [LMC] and 19.12±0.03(random)±0.10(systematic)19.12\pm0.03{\rm(random)}\pm0.10{\rm(systematic)} mag [SMC]). These new MC distances lead to the relative distance, Δμ=0.48±0.03\Delta\mu=0.48\pm0.03 mag (FU, logP=1\log P=1) and Δμ=0.52±0.03\Delta\mu=0.52\pm0.03 mag (FO, logP=0.5\log P=0.5),which agrees quite well with previous estimates based on robust distance indicators.Comment: 17 pages, 7 figure

    Classical Cepheids, what else?

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    We present new and independent estimates of the distances to the Magellanic Clouds (MCs) using near-infrared (NIR) and optical--NIR period--Wesenheit (PW) relations. The slopes of the PW relations are, within the dispersion, linear over the entire period range and independent of metal content. The absolute zero points were fixed using Galactic Cepheids with distances based on the infrared surface-brightness method. The true distance modulus we found for the Large Magellanic Cloud---(mM)0=18.48±0.01±0.10(m-M)_0 = 18.48 \pm 0.01 \pm 0.10 mag---and the Small Magellanic Cloud---(mM)0=18.94±0.01±0.10(m-M)_0 = 18.94 \pm 0.01 \pm 0.10 mag---agree quite well with similar distance determinations based on robust distance indicators. We also briefly discuss the evolutionary and pulsation properties of MC Cepheids

    Variable stars in Terzan 5: additional evidence of multi-age and multi-iron stellar populations

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    Terzan 5 is a complex stellar system in the Galactic bulge, harboring stellar populations with very different iron content ({\Delta}[Fe/H] ~1 dex) and with ages differing by several Gyrs. Here we present an investigation of its variable stars. We report on the discovery and characterization of three RR Lyrae stars. For these newly discovered RR Lyrae and for six Miras of known periods we provide radial velocity and chemical abundances from spectra acquired with X-SHOOTER at the VLT. We find that the three RR Lyrae and the three short period Miras (P<300 d) have radial velocity consistent with being Terzan 5 members. They have sub-solar iron abundances and enhanced [{\alpha}/Fe], well matching the age and abundance patterns of the 12 Gyr metal-poor stellar populations of Terzan 5. Only one, out of the three long period (P>300 d) Miras analyzed in this study, has a radial velocity consistent with being Terzan 5 member. Its super-solar iron abundance and solar-scaled [{\alpha}/Fe] nicely match the chemical properties of the metal rich stellar population of Terzan 5 and its derived mass nicely agrees with being several Gyrs younger than the short period Miras. This young variable is an additional proof of the surprising young sub-population discovered in Terzan 5.Comment: 20 pages, 4 figures, in press on the Ap

    Serum vitamin D in patients with mild cognitive impairment and Alzheimer's disease

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    Objectives: To determine the relevance of Mini-Mental State Examination (MMSE), serum 25-hydroxyvitamin D (25(OH)D3), and 1,25(OH)2D3 concentrations to mild cognitive impairment (MCI) and various stages of Alzheimer's disease (AD). Materials and Methods: The study included 230 participants (>74 years) allocated to three main groups: 1-healthy subjects (HS, n = 61), 2-patients with MCI (n = 61), and 3- patients with Alzheimer's disease (AD) subdivided into three stages: mild (n = 41), moderate (n = 35), and severe AD (n = 32). The cognitive status was evaluated using MMSE. Serum 25 (OH)D3 (ng/ml) and 1,25(OH)2D3 concentrations (pg/ml) were determined by competitive radioimmunoassay. Results: MMSE scores and 25(OH)D3 were decreased in MCI and all stages of the AD in both genders. MMSE variability was due to gender in HS (11%) and to 25(OH)D3 in MCI (15%) and AD (26%). ROC analysis revealed an outstanding property of MMSE in diagnosis of MCI (AUC, 0.906; CI 95%, 0.847–0.965; sensitivity 82%; specificity, 98%) and AD (AUC, 0.997; CI 95%, 0.992–1; sensitivity, 100%; specificity, 98%). 25(OH)D3 exhibited good property in MCI (AUC, 0.765; CI 95%, 0.681–0.849; sensitivity, 90%; specificity, 54%) and an excellent property in diagnosis of AD (AUC, 0.843; CI 95%, 0.782–0.904; sensitivity, 97%; specificity, 79%). Logistic analyses revealed that, in MCI, MMSE could predict (or classify correctly) with 97.6% accuracy (Wald, 15.22, β, −0.162; SE, 0.554; OR = 0.115:0.039–0.341; p =.0001), whereas 25(OH)D3 with 80% accuracy (Wald, 41,013; β, −0.213; SE, 0.033; OR = 0.808: 0.757–863; p =.0001). 25(OH)D3 was the only significant predictor for the severe AD and contributed to MMSE variability. Age and gender were significant predictors only in the moderate AD. In patients with MCI, 25(OH)D3 and 1,25(OH)2D3 were correlated men, but in case of the AD, they were correlated in women. Conclusions: MMSE and serum 25(OH)D3 concentrations could be useful biomarkers for prediction and diagnosis of MCI and various stages of the AD. The results support the utility of vitamin D supplementation in AD therapy regimen. © 2018 The Authors. Brain and Behavior published by Wiley Periodicals, Inc
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