Low-temperature specific heat for ferromagnetic and antiferromagnetic orders in CaRu1-xMnxO3

Low-temperature specific heat of CaRu1-xMnxO3 was measured to clarify the role of d electrons in ferromagnetic and antiferromagnetic orders observed above x=0.2. Specific heat divided by temperature C_p/T is found to roughly follow a T^2 function, and relatively large magnitudes of electronic specific heat coefficient gamma were obtained in wide x range. In particular, gamma is unchanged from the value at x=0 (84 mJ/K^2 mol) in the paramagnetic state for x<=0.1, but linearly reduced with increasing x above x= 0.2. These features of gamma strongly suggest that itinerant d electrons are tightly coupled with the evolution of magnetic orders in small and intermediate Mn concentrations.Comment: 4 pages, 2 figures, to be published in J. Phys.: Conf. Ser. (SCES 2011, Cambridge, UK

Gain in a quantum wire laser of high uniformity

A multi-quantum wire laser operating in the 1-D ground state has been achieved in a very high uniformity structure that shows free exciton emission with unprecedented narrow width and low lasing threshold. Under optical pumping the spontaneous emission evolves from a sharp free exciton peak to a red-shifted broad band. The lasing photon energy occurs about 5 meV below the free exciton. The observed shift excludes free excitons in lasing and our results show that Coulomb interactions in the 1-D electron-hole system shift the spontaneous emission and play significant roles in laser gain.Comment: 4 pages, 4 figures, prepared by RevTe

Mother-to-embryo vitellogenin transport in a viviparous teleost Xenotoca eiseni

魚類がお腹の子供に与える栄養素を解明 --哺乳類が失った遺伝子を利用して胎生機構を獲得--. 京都大学プレスリリース. 2019-10-09.Vitellogenin (Vtg), a yolk nutrient protein that is synthesized in the livers of female animals, and subsequently carried into the ovary, contributes to vitellogenesis in oviparous animals. Thus, Vtg levels are elevated during oogenesis. In contrast, Vtg proteins have been genetically lost in viviparous mammals, thus the yolk protein is not involved in their oogenesis and embryonic development. In this study, we identified Vtg protein in the livers of females during the gestation of the viviparous teleost, Xenotoca eiseni. Although vitellogenesis is arrested during gestation, biochemical assays revealed that Vtg protein was present in ovarian tissues and lumen fluid. The Vtg protein was also detected in the trophotaeniae of the intraovarian embryo. Immunoelectron microscopy revealed that Vtg protein is absorbed into intracellular vesicles in the epithelial cells of the trophotaeniae. Furthermore, extraneous Vtg protein injected into the abdominal cavity of a pregnant female was subsequently detected in the trophotaeniae of the intraovarian embryo. Our data suggest that the yolk protein is one of the matrotrophic factors supplied from the mother to the intraovarian embryo during gestation in X. eiseni

Suzaku X-Ray Imaging and Spectroscopy of Cassiopeia A

Suzaku X-ray observations of a young supernova remnant, Cassiopeia A, were carried out. K-shell transition lines from highly ionized ions of various elements were detected, including Chromium (Cr-Kalpha at 5.61 keV). The X-ray continuum spectra were modeled in the 3.4--40 keV band, summed over the entire remnant, and were fitted with a simplest combination of the thermal bremsstrahlung and the non-thermal cut-off power-law models. The spectral fits with this assumption indicate that the continuum emission is likely to be dominated by the non-thermal emission with a cut-off energy at > 1 keV. The thermal-to-nonthermal fraction of the continuum flux in the 4-10 keV band is best estimated as ~0.1. Non-thermal-dominated continuum images in the 4--14 keV band were made. The peak of the non-thermal X-rays appears at the western part. The peak position of the TeV gamma-rays measured with HEGRA and MAGIC is also shifted at the western part with the 1-sigma confidence. Since the location of the X-ray continuum emission was known to be presumably identified with the reverse shock region, the possible keV-TeV correlations give a hint that the accelerated multi-TeV hadrons in Cassiopeia A are dominated by heavy elements in the reverse shock region.Comment: Publ. Astron. Soc. Japan 61, pp.1217-1228 (2009

Power exhaust concepts and divertor designs for Japanese and European DEMO fusion reactors

Concepts of the power exhaust and divertor design have been developed, with a high priority in the pre-conceptual design phase of the Japan-Europe broader approach DEMO design activity (BA DDA). Common critical issues are the large power exhaust and its fraction in the main plasma and divertor by the radiative cooling (P radtot/P heat 0.8). Different exhaust concepts in the main plasma and divertor have been developed for Japanese (JA) and European (EU) DEMOs. JA proposed a conventional closed divertor geometry to challenge large P sep/R p handling of 30-35 MW m-1 in order to maintain the radiation fraction in the main plasma at the ITER-level (f radmain = P radmain/P heat ∼ 0.4) and higher plasma performance. EU challenged both increasing f radmain to ∼0.65 and handling the ITER-level P sep/R p in the open divertor geometry. Power exhaust simulations have been performed by SONIC (JA) and SOLPS5.1 (EU) with corresponding P sep = 250-300 MW and 150-200 MW, respectively. Both results showed that large divertor radiation fraction (P raddiv/P sep 0.8) was required to reduce both peak q target (10 MW m-2) and T e,idiv. In addition, the JA divertor performance with EU-reference P sep of 150 MW showed benefit of the closed geometry to reduce the peak q target and T e,idiv near the separatrix, and to produce the partial detachment. Integrated designs of the water cooled divertor target, cassette and coolant pipe routing have been developed in both EU and JA, based on the tungsten (W) monoblock concept with Cu-alloy pipe. For year-long operation, DEMO-specific risks such as radiation embrittlement of Cu-interlayers and Cu-alloy cooling pipe were recognized, and both foresee higher water temperature (130 °C-200 °C) compared to that for ITER. At the same time, several improved technologies of high heat flux components have been developed in EU, and different heat sink design, i.e. Cu-alloy cooling pipes for targets and RAFM steel ones for the baffle, dome and cassette, was proposed in JA. The two approaches provide important case-studies of the DEMO divertor, and will significantly contribute to both DEMO designs

RAPID-CYCLING POWER SUPPLIES FOR THE J-PARC RCS SEXTUPOLE MAGNETS

Abstract In the J-PARC 3-GeV synchrotron, the sextupole magnets were excited with DC-biased 25Hz sinusoidal waveform. Direct excitation for the rapid-cycling magnets causes large reactive power and voltage fluctuation in DC-link. This paper proposes design of the smoothing circuit for direct excitation of the rapid-cycling magnets. Especially, theoretical power-flow analysis shows a relationship between required DC-capacitance and voltage fluctuation in DC-link. Experimental results obtained from practical power-supply agree with analytical results

Effect of modulation-doping on luminescence properties of plasma assisted MBE-grown GaN/AIGaN quantum well

In order to improve the crystal quality of GaN-based light emitting devices, photoluminescence (PL) characterization of below-gap states in plasma assisted MBE-grown GaN/AlGaN quantum well (QW) structures has been done by utilizing a below-gap excitation (BGE) light in addition to an above-gap excitation light. The decrease of the band-edge PL intensity due to the addition of the BGE of 1.17 eV indicates the presence of an energy-matched below-gap state in the two-wavelength excited PL. In continuation to our previous efficiency improvement by applying modulation-doping to GaAs/AlGaAs QW's. we focused on several undopcd and Si-doped GaN/AlGaN QW's. Experimental results showed that Si modulation-doping reduces the density of below-gap states in the QW region, hence it is promising for increasing internal quantum efficiency of GaN-based QW's

Basic Taste Stimuli Elicit Unique Responses in Facial Skin Blood Flow

Facial expression changes characteristically with the emotions induced by basic tastes in humans. We tested the hypothesis that the five basic tastes also elicit unique responses in facial skin blood flow. Facial skin blood flow was measured using laser speckle flowgraphy in 16 healthy subjects before and during the application of basic taste stimuli in the oral cavity for 20 s. The skin blood flow in the eyelid increased in response to sweet and umami taste stimuli, while that in the nose decreased in response to a bitter stimulus. There was a significant correlation between the subjective hedonic scores accompanying these taste stimuli and the above changes in skin blood flow. These results demonstrate that sweet, umami, and bitter tastes induce unique changes in facial skin blood flow that reflect subjective hedonic scores

GWAS of bipolar disorder

Genome-wide association studies (GWASs) have identified several susceptibility loci for bipolar disorder (BD) and shown that the genetic architecture of BD can be explained by polygenicity, with numerous variants contributing to BD. In the present GWAS (Phase I/II), which included 2964 BD and 61 887 control subjects from the Japanese population, we detected a novel susceptibility locus at 11q12.2 (rs28456, P=6.4 × 10−9), a region known to contain regulatory genes for plasma lipid levels (FADS1/2/3). A subsequent meta-analysis of Phase I/II and the Psychiatric GWAS Consortium for BD (PGC-BD) identified another novel BD gene, NFIX (P best=5.8 × 10−10), and supported three regions previously implicated in BD susceptibility: MAD1L1 (P best=1.9 × 10−9), TRANK1 (P best=2.1 × 10−9) and ODZ4 (P best=3.3 × 10−9). Polygenicity of BD within Japanese and trans-European-Japanese populations was assessed with risk profile score analysis. We detected higher scores in BD cases both within (Phase I/II) and across populations (Phase I/II and PGC-BD). These were defined by (1) Phase II as discovery and Phase I as target, or vice versa (for ‘within Japanese comparisons’, Pbest~10−29, R2~2%), and (2) European PGC-BD as discovery and Japanese BD (Phase I/II) as target (for ‘trans-European-Japanese comparison,’ Pbest~10−13, R2~0.27%). This ‘trans population’ effect was supported by estimation of the genetic correlation using the effect size based on each population (liability estimates~0.7). These results indicate that (1) two novel and three previously implicated loci are significantly associated with BD and that (2) BD ‘risk’ effect are shared between Japanese and European populations