Angle-resolved photoemission study of MX-chain compound [Ni(chxn)2_2Br]Br2_2

We report on the results of angle-resolved photoemission experiments on a quasi-one-dimensional $MX$-chain compound [Ni(chxn)$_2$Br]Br$_2$ (chxn = 1$R$,2$R$-cyclohexanediamine), a one-dimensional Heisenberg system with $S=1/2$ and $J \sim 3600$ K, which shows a gigantic non-linear optical effect. A "band" having about 500 meV energy dispersion is found in the first half of the Brillouin zone $(0\le kb/\pi <1/2)$, but disappears at $kb / \pi \sim 1/2$. Two dispersive features, expected from the spin-charge separation, as have been observed in other quasi-one-dimensional systems like Sr$_2$CuO$_3$, are not detected. These characteristic features are well reproduced by the $d$-$p$ chain model calculations with a small charge-transfer energy $\Delta$ compared with that of one-dimensional Cu-O based compounds. We propose that this smaller $\Delta$ is the origin of the absence of clear spin- and charge-separation in the photoemission spectra and strong non-linear optical effect in [Ni(chxn)$_2$Br]Br$_2$.Comment: 4 pages, 3 figure

Fans and polytopes in tilting theory

For a finite dimensional algebra $A$ over a field $k$, the 2-term silting complexes of $A$ gives a simplicial complex $\Delta(A)$ called the $g$-simplicial complex. We give tilting theoretic interpretations of the $h$-vectors and Dehn-Sommerville equations of $\Delta(A)$. Using $g$-vectors of 2-term silting complexes, $\Delta(A)$ gives a nonsingular fan $\Sigma(A)$ in the real Grothendieck group $K_0(\mathrm{proj } A)_\mathbb{R}$ called the $g$-fan. For example, the fan of $g$-vectors of a cluster algebra is given by the $g$-fan of a Jacobian algebra of a non-degenerate quiver with potential. We give several properties of $\Sigma(A)$ including idempotent reductions, sign-coherence, Jasso reductions and a connection with Newton polytopes of $A$-modules. Moreover, $\Sigma(A)$ gives a (possibly infinite and non-convex) polytope $P(A)$ in $K_0(\mathrm{proj } A)_\mathbb{R}$ called the $g$-polytope of $A$. We call $A$ $g$-convex if $P(A)$ is convex. In this case, we show that it is a reflexive polytope, and that the dual polytope is given by the 2-term simple minded collections of $A$. We give an explicit classification of $g$-convex algebras of rank $2$. We classify algebras whose $g$-polytopes are smooth Fano. We classify classical and generalized preprojective algebras which are $g$-convex, and also describe their $g$-polytope as the dual polytopes of short root polytopes of type $A$ and $B$. We also classify Brauer graph algebras which are $g$-convex, and describe their $g$-polytopes as root polytopes of type $A$ and $C$.Comment: 70 page

Fans and polytopes in tilting theory II: gg-fans of rank 2

The $g$-fan of a finite dimensional algebra is a fan in its real Grothendieck group defined by tilting theory. We give a classification of complete $g$-fans of rank 2. More explicitly, our first main result asserts that every complete sign-coherent fan of rank 2 is a $g$-fan of some finite dimensional algebra. Our proof is based on three fundamental results, Gluing Theorem, Rotation Theorem and Subdivision Theorem, which realize basic operations on fans in the level of finite dimensional algebras. For each of 16 convex sign-coherent fans $\Sigma$ of rank 2, our second main result gives a characterization of algebras $A$ of rank 2 satisfying $\Sigma(A)=\Sigma$. As a by-product of our method, we prove that for each positive integer $N$, there exists a finite dimensional algebra $A$ of rank 2 such that the Hasse quiver of the poset of 2-term silting complexes of $A$ has precisely $N$ connected components.Comment: 37 pages, v2: Fixed typos, updated references and added section

The ASTRO-H X-ray Observatory

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray

Fully Endoscopic Transcylinder Trans-Magendie Foraminal Approach for Fourth Ventricular Cavernoma: A Technical Case Report

Background: Neuroendoscopy offers wide and close surgical views with fine illumination, even in deep surgical sites. Furthermore, transcylinder surgery has the advantage that a tubular retractor can protect critical neurovascular structures in the surgical corridor. These advantages of neuroendoscopy and transcylinder surgery can contribute to safer and less invasive surgical approaches for deep-seated fourth ventricular lesions, for which various critical neurovascular structures exist along the surgical route. Case Description: A 54-year-old man with a fourth ventricular cavernoma underwent tumor resection via the endoscopic transcylinder trans-Magendie foraminal approach. A 6.8-mm transparent sheath (cylinder) was introduced into the fourth ventricle via the foramen of Magendie without incisions in the inferior medullary velum or the tela choroidea, resulting in the minimal retraction of and trauma to critical neurovascular structures in the surgical corridor. Under the view of a 2.7-mm rigid neuroendoscope, the lesion was completely removed with preservation of a venous anomaly on the ventral side of the aqueduct of Sylvius. Neuroendoscopy could offer a fine surgical view even under continuous irrigation with artificial cerebrospinal fluid; it prevented collapse of the fourth ventricle and facilitated anatomic understanding by the surgeons. The postoperative course was uneventful. Conclusions: Our novel approach can be an effective surgical option for fourth ventricular lesions with minimal cerebellar retraction and injury.ファイル公開：2021-10-01journal articl

A Novel High-Speed Electromagnetic Oscillatory Actuator With a Dual Mover for Optical Scanner Applications

In this paper, we propose a high-speed moving magnet-type oscillatory actuator in which a dual-mover structure is designed to reduce magnetic damping force. Both movers have independent resonant frequency, and the actuator is driven at the larger resonant frequency. The smaller mover serves as the optical scanning element and maintains large oscillation amplitude. The larger mover, with moving magnets, serves as the magnetic driving element and maintains relatively smaller amplitude because of the magnetic damping.ArticleIEEE TRANSACTIONS ON MAGNETICS. 50(11):8203504 (2014)journal articl

Novel multicellular prokaryote discovered next to an underground stream

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The Quiescent Intracluster Medium in the Core of the Perseus Cluster

Clusters of galaxies are the most massive gravitationally-bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and a host of astrophysical processes. Knowledge of the dynamics of the pervasive hot gas, which dominates in mass over stars in a cluster, is a crucial missing ingredient. It can enable new insights into mechanical energy injection by the central supermassive black hole and the use of hydrostatic equilibrium for the determination of cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50 million K diffuse hot plasma filling its gravitational potential well. The Active Galactic Nucleus of the central galaxy NGC1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These likely induce motions in the intracluster medium and heat the inner gas preventing runaway radiative cooling; a process known as Active Galactic Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus cluster core, which reveal a remarkably quiescent atmosphere where the gas has a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s is found across the 60 kpc image of the cluster core. Turbulent pressure support in the gas is 4% or less of the thermodynamic pressure, with large scale shear at most doubling that estimate. We infer that total cluster masses determined from hydrostatic equilibrium in the central regions need little correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July

KOnezumi: a web application for automating gene disruption strategies to generate knockout mice

A Summary: Although gene editing using the CRISPR/Cas9 system enables the rapid generation of knockout mice, constructing an optimal gene disruption strategy is still labourious. Here, we propose KOnezumi, a simple and user-friendly web application, for use in automating the design of knockout strategies for multiple genes. Users only need to input gene symbols, and then KOnezumi returns target exons, gRNA candidates to delete the target exons, genotyping PCR primers, nucleotide sequences of the target exons and coding sequences of expected deletion products. KOnezumi enables users to easily and rapidly apply a rational strategy to accelerate the generation of KO mic