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The Mekong giant catfish (MGC), Pangasianodon gigas, is one of the world's largest catfish species. Endemic to the Mekong River system, the MGC is critically endangered. Six MGC were transported from Thailand to the Gifu World Freshwater Aquarium (GWFA) in Japan in May 2004. The MGC have not been measured since they were introduced to the GWFA due to the challenges associated with their large size. Traditional methods, such as anesthesia and net-capture, could harm the fish, potentially reducing the population further. However, understanding the ecology of the species is essential to conservation efforts. Seasonal feeding rhythms and long-term fasting were previously observed in captive MGCs. To investigate the effect of long-term fasting on MGC growth, total length measurements are necessary. In this study, we applied a noncontact method to estimate the total length via image analysis. We shot a stereo-video of free-swimming MGC in the aquarium tank using two digital video cameras and analyzed the 3D images using the direct linear transformation method. We successfully estimated the total length of each MGC individual without contacting the fish. This accurate estimation method is versatile, simple, and useful in aquarium breeding and is also recommended from the viewpoint of animal welfare because it is a noninvasive method of measurement.

Adhesion is an interfacial phenomenon that is critical for assembling carbon structural composites for next-generation aircraft and automobiles. However, there is limited understanding of adhesion on the molecular level because of the difficulty in revealing the individual bonding factors. Here, using soft X-ray spectromicroscopy we show the physical and chemical states of an adhesive interface composed of a thermosetting polymer of 4,4’-diaminodiphenylsulfone-cured bisphenol A diglycidyl ether adhered to a thermoplastic polymer of plasma-treated polyetheretherketone. We observe multiscale phenomena in the adhesion mechanisms, including sub-mm complex interface structure, sub-μm distribution of the functional groups, and molecular-level covalent-bond formation. These results provide a benchmark for further research to examine how physical and chemical states correlate with adhesion, and demonstrate that soft X-ray imaging is a promising approach for visualizing the physical and chemical states at adhesive interfaces from the sub-mm level to the molecular level. Understanding adhesion mechanisms for polymer composites is challenging due to the bonded interface being buried. Here, soft X-rays are used to probe the chemical and physical nature of the interface, revealing multiscale factors that influence the adhesion mechanism and bond strength.

Using X-ray absorption spectroscopy (XAS), we investigated local chemical interactions in thermosetting epoxy resins for structural composites: N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane (...

A scanning soft X-ray spectromicroscope was recently developed based mainly on the photon-in/photon-out measurement scheme for the investigation of local electronic structures on the surfaces and interfaces of advanced materials under conditions ranging from low vacuum to helium atmosphere. The apparatus was installed at the soft X-ray beamline (BL17SU) at SPring-8. The characteristic features of the apparatus are described in detail. The feasibility of this spectromicroscope was demonstrated using soft X-ray undulator radiation. Here, based on these results, element-specific two-dimensional mapping and micro-XAFS (X-ray absorption fine structure) measurements are reported, as well as the observation of magnetic domain structures from using a reference sample of permalloy micro-dot patterns fabricated on a silicon substrate, with modest spatial resolution (e.g. ∼500 nm). Then, the X-ray radiation dose for Nafion® near the fluorine K-edge is discussed as a typical example of material that is not radiation hardened against a focused X-ray beam, for near future experiments.

Case Presentation A 78-year-old man with asthma and COPD presented with shortness of breath, cough, and severe malaise for 4 days. Upon arrival, the patient was conscious and body temperature was 37.5°C. Arterial oxygen saturation (Spo2) was 80% on room air. Laboratory data demonstrated a WBC count of 17,400/μL (89.5% neutrophils) and C-reactive protein of 5.00 mg/dL. CT scan of chest revealed scattered ground-glass in the upper right lobe and thickening of the bronchial wall. Based on these findings, acute bronchopneumonia was diagnosed and antibacterial therapy was started. The day after admission, the patient's general condition and shortness of breath had gradually improved. We treated and observed him carefully for 10 days in the hospital on antibacterial therapy because of his underlying comorbidities (asthma and COPD) and his ongoing hypoxemia. Three days after discharge, the patient re-presented with shortness of breath, hypoxemia, and loss of appetite. The patient was hospitalized for a second time.

The local electronic state of the N,N,N',N'-tetraglycidyl-4,4′-diaminodiphenylmethane epoxy resin cured with 4,4′-diaminodiphenylsulfone (TGDDM-DDS), one of model adhesive materials, was investigated by the O K-edge X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES). The total-electron-yield XAS spectra for TGDDM-DDS as a function of the X-ray dose exhibit the exponential-like decrease in the curing-derived pre-edge intensity due to the radiation damage. The quantitative analysis on the pre-edge intensity with respect to the X-ray dose enables the determination of the critical absorbed dose for the chemical change on TGDDM-DDS as 3.83 ± 0.01 MGy at 300 K. By using resonant XES with the well-focused X-ray beam, we found that (i) the charged-particle equilibrium exists for the soft X-rays in the range of at least 0.001–0.847 mm2 beam spot and that (ii) the half of the critical absorbed dose can be regarded as the limit indicator for the non-destructive chemical-state characterization on resinous adhesive materials and interfaces using soft X-rays.

Ge atoms segregating on zirconium diboride thin films grown on Ge(111) were found to crystallize into a two-dimensional bitriangular structure, which was recently predicted to be a flat band material through an embedded kagome lattice. Angle-resolved photoelectron emission experiments together with theoretical calculations pointed out the existence of a nearly flat band in spite of non-negligible in-plane long-range hopping and interactions with the substrate. This provides an experimental verification for the fact that a flat band can emerge from the electronic coupling between atoms and not from the geometry of the atomic structure.

The Mekong giant catfish

The photoelectron angular distribution of organic thin films is essential in the discussion of the (opto)electronic properties from the viewpoints of the spatial distribution of molecular orbitals and the interaction of molecular electronic states. We discuss the role of the weak intermolecular interaction in highly ordered aromatic molecules on the photoelectron angular distribution obtained by angle-resolved photoemission spectroscopy (ARPES). The experimental and theoretical investigation performed for superstructures of polycyclic aromatic hydrocarbons (PAHs) on Au(111) indicates that at least the intramolecular single-scattering process is necessary to be considered in simulation of the orbital tomography. Furthermore, ARPES spectra for various PAH monolayers reveal that the weak π-band dispersion is dependent on the surface Brillouin zone of the monolayer but not of the substrate. The long-range lateral intermolecular interaction in highly ordered aromatic molecules plays a main role in the π-band d...

The orbital-specific interfacial and intermolecular interactions in crystalline films of iron phthalocyanine (FePc) grown on an Au(111) surface were studied by means of angle-resolved photoemission spectroscopy (ARPES) with synchrotron radiation. The temperature-dependent ARPES measurement on the FePc monolayer reveals the formation of the molecule–metal hybrid state together with the Kondo resonance state below the Fermi level. These interface-specific states are derived from the electronic coupling of the Fe 3d orbital in the molecule with the Au(111) surface electron. For the flat-lying FePc multilayer on Au(111), the photon-energy-dependent ARPES spectra reveal the intermolecular valence-band dispersion for the C 2p-derived state, while the Fe 3d-derived state does not show such dispersion, indicating the localized Fe 3d spin state. These orbital-specific interactions play crucial roles in the unique electronic and magnetic properties of FePc.

The electronic structure of 7,7,8,8-tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-TCNQ (F4TCNQ) monolayers on Au(111) has been investigated by means of angle-resolved photoemission spectroscopy (ARPES) with synchrotron radiation. In contrast to the physisorbed TCNQ/Au(111) interface, the high-resolution core-level photoemission spectra and the low-energy electron diffraction at the F4TCNQ/Au(111) interface show evidence for the strong charge transfer (CT) from Au to F4TCNQ and for the Au atom segregation from the underlying Au(111) surface, suggesting a possible origin of the spontaneous formation of the two-dimensional F4TCNQ-Au network. The ARPES experiment reveals a low hole-injection barrier and large band dispersion in the CT-induced topmost valence level of the F4TCNQ-Au network with 260 meV bandwidth due to the adatom-mediated intermolecular interaction. These results indicate that strong electron acceptor molecules with metal adatoms can form high hole-mobility molecular layers by contro...

Single crystalline bismuth (Bi) is known to have a peculiar electronic structure which is very close to the topological phase transition. The modification of the surface states of Bi depending on the temperature are revealed by angle-resolved photoelectron spectroscopy (ARPES). At low temperature, the upper branch of the surface state merged to the projected bulk conduction bands around the $\bar{M}$ point of the surface Brillouin zone (SBZ). In contrast, the same branch merged to the projected bulk valence bands at high temperature (400 K). Such behavior could be interpreted as a topological phase transition driven by the temperature, which might be applicable for future spin-thermoelectric devices. We discuss the possible mechanisms to cause such transition, such as the thermal lattice distortion and electron-phonon coupling., 15 pages with 6 figures (single column)

In order to discuss the site specificity in the organic/metal interfacial interaction, the electronic structure of the well-ordered interface of cobalt phthalocyanine (CoPc) adsorbed on Au(111) is studied by angle-resolved photoemission spectroscopy (ARPES) with synchrotron radiation. The core-level and valence-band ARPES spectra show an evidence for the strong CoPc/Au(111) chemical interaction localized at the Co site and the resultant formation of the interface states. The CoPc/Au(111) interface states are formed around the highest occupied molecular orbital (HOMO) and just below the Fermi level (EF) with the nondispersive and dispersive characteristics, respectively. The nondispersive interface state around the HOMO is attributed to the intramolecular πPc–dCo mixed orbital induced by the site-specific interfacial interaction. The dispersive interface state below EF originates from the adsorbate-induced modification of the Au(111) Shockley state, which shows difference between CoPc and metal-free Pc (H2...

The Mekong giant catfish Pangasianodon gigas is one of the largest freshwater fish, measuring up to 3 m in total length. This study was designed to determine the feeding habits of P. gigas to better understand how the fish achieve their large body size. We compared the relationship between gut length (GL) and total length (TL) among related species in superfamily Bagroidea, order Siluriformes (Pangasianodon hypophthalmus and Hemibagrus nemurus) in the Kaeng Krachan reservoir, Thailand. The mean relative gut length (RGL = GL / TL) of P. gigas was 3.50, showing that they have relatively long guts, with values more similar to those of omnivorous P. hypophthalmus (RGL = 3.70) than to those of carnivorous H. nemurus (RGL = 0.92). In the allometric relationship (i.e., log10 GL = log10 a + b log10 TL), the slope close to 1 for P. gigas (b = 1.07) has been widely observed in carnivores, while P. gigas has a greater intercept of the linear equation than P. hypophthalmus and H. nemurus, resulting in a similar GL of P. gigas to omnivorous P. hypophthalmus at approximately 35 cm in TL. Moreover, GL of P. gigas at 150 to 250 cm in TL showed great variations (RGL = 1.35-6.32). The variation in RGL for P. gigas seemed to result from a poor nutritional state. In conclusion, P. gigas is suggested to feed on indigestible materials such as plants, algae, and sediments, and potentially experience fasting in a reservoir.

This paper gives elements in the (skew) center of the generalized quantum group corresponding to its irreducible finite dimensional modules. Finally we give a conjecture stating that those must form a basis of the center., Comment: 17 pages

We introduce the definition of the typical irreducible modules of the generalized quantum groups, and prove the Weyl-Kac-type formulas of their characters. As a by-product, we obtain the Weyl-Kac-type character formulas of the typical irreducible modules of the quantum superalgebras associated with the basic classical Lie superalgebras, which is explained in Introduction., Comment: 28 pages

Functionalities of organic semiconductors are governed not only by individual properties of constituent molecules but also by solid-state electronic states near the Fermi level such as frontier molecular orbitals, depending on weak intermolecular interactions in various conformations. The individual molecular property has been widely investigated in detail; on the other hand, the weak intermolecular interaction is difficult to investigate precisely due to the presence of the structural and thermal energy broadenings in organic solids. Here we show quite small but essential intermolecular valence band dispersions and their temperature dependence of sub-0.1-eV scale in crystalline films of metal phthalocyanines (H 2 Pc, ZnPc, CoPc, MnPc, and F 16 ZnPc) by using angle-resolved photoemission spectroscopy (ARPES) with synchrotron radiation. The observed bands show intermolecular and site dependent dispersion widths, phases, and periodicities, for different chemical substitution of terminal groups and central metals in the phthalocyanine molecule. The precise and systematic band-dispersion measurement would be a credible approach toward the comprehensive understanding of intermolecular interactions and resultant charge transport properties as well as their tuning by substituents in organic molecular systems.

We give a new proof of the presentation of the affine Lie superalgebra $${\mathrm {G}}^{(1)}(3)$$ using a Weyl groupoid.

Let U(χ) be a generalized quantum group such that dimU+(χ) = ∞, |R+(χ)| < ∞, and R+(χ) is irreducible, where U+(χ) is the positive part of U(χ), and R+(χ) is the Kharchenko’s positive root system of U+(χ). In this paper, we give a list of finite-dimensional irreducible highest weight U(χ)-modules, relying on a special reduced expression of the longest element of the Weyl groupoid of U(χ).

Edges on the cleaved graphite crystal surface were found to be preferentially oriented perpendicularly to the hexagonal perimeter facet of the graphite single crystal assigned to the zig-zag-type e...

We have developed an acceptance-cone-tunable (ACT) electron spectrometer for the highly efficient constant-energy photoelectron mapping of functional materials. The ACT spectrometer consists of the hemispherical deflection analyzer with the mesh-type electrostatic lens near the sample. The photoelectron trajectory can be converged by applying a negative bias to the sample and grounding the mesh lens and the analyzer entrance. The performance of the present ACT spectrometer with neither rotating nor tilting of the sample is demonstrated by the wide-angle observation of the well-known π-band dispersion of a single crystalline graphite over the Brillouin zone. The acceptance cone of the spectrometer is expanded by a factor of 3.30 when the negative bias voltage is 10 times as high as the kinetic energy of photoelectrons.

We introduce nil-Hecke algebras for Weyl groupoids. We describe a basis and some properties of these algebras which lead to a notion of Bruhat order for Weyl groupoids., Comment: 13 pages

We present the electronic structure of various pentacene thin films grown on Au(1 1 1), Cu(1 1 1), Cu(1 0 0), and Cu(1 1 0) surfaces studied by angle-resolved ultraviolet photoemission spectroscopy using synchrotron radiation. A systematic variation of the metal surface such as the substrate metal and its surface symmetry allows a comprehensive discussion on the correlation between the electronic structure and the interface geometric structure. In the monolayer regime, we observed the evidence of the formation of the organic–metal interface state depending on the metal surface, i.e., the interface geometric structure. This evidence is explained by the different organic–metal and intermolecular interactions, which originate from the hybridization of the molecular orbitals with the metal wavefunction. These interface geometric and electronic phenomena can be a seed for the subsequent film growth and resultant films electronic structure.

Although a great deal of research has been conducted on the electrical properties of organic devices, numerous crucial problems still remain. Of these, the study of charge mobility in organic semiconductor systems has been one of the most important subjects that has remained a puzzle for many years. It is essential to quantitatively understand conduction charge-molecular vibration coupling as well as the intermolecular interaction to discuss mobility. This article describes recent successes with direct measurements of valence hole–vibration coupling in ultrathin films of organic semiconductors with ultraviolet photoelectron spectroscopy (UPS), which can be used to experimentally study charge mobility based on energy and momentum conservation rules. The method may thus be categorized as a first-principles study of charge mobility. The detection of hole–vibration coupling of the highest occupied molecular orbital (HOMO) state in a thin film by UPS is essential to comprehending hole-hopping transport and polaron-related transport in organic semiconductors. We also need to experimentally determine energy-band dispersion or energy-level splitting in a molecular multilayer to obtain information on intermolecular interactions. Since the information on these is concealed behind the finite bandwidth of the HOMO in UPS spectra, we need to obtain high-resolution UPS measurements on organic thin films. Only careful measurements can attain the high-resolution spectra and provide these key parameters in hole-transport dynamics. A key method in achieving such high-resolution UPS measurements is also described.

We analyzed the vacuum level shift (Δ) induced by the dipole layer at the interfaces between perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) and noble metals (Au, Ag and Cu). The variation of Δ observed by ultraviolet photoelectron spectroscopy does not show a simple dependence on the metal work function, which contradicts the prediction by the induced density of interface states (IDIS) model proposed by Vazquez et al. [H. Vazquez, F. Flores, R. Oszwaldowski, J. Ortega, R. Perez and A. Kahn, Appl. Surf. Sci 234 (2004) 107]. We found that two factors, (1) the energy separation between the lowest unoccupied molecular orbital (LUMO) of PTCDA and the metal d-band states, which results in the attractive effect due to the orbital hybridization, and (2) the coupling matrix element between the adsorbate states and the metal d-band states, which result in the repulsive effect due to the orbital orthogonalization between the adsorbate states and the metal d-band states, have a clear correlation with the Δ formation. Our results indicate that the interactions between the molecular orbitals of PTCDA and the metal d-band states play an important role in determining the interfacial electronic structure, which has not been taken into account within the framework of the IDIS model.

We report the electronic structure and the charge transport mechanism of highly ordered films of pentacene on Cu(1 10) surface studied by angle-resolved ultraviolet photoemission spectroscopy using synchrotron radiation. For a flat-lying monolayer film, we observed the evidences of (i) formation of the interface states and (ii) two-dimensional intermolecular band dispersion of the resultant interface states, which may originate from the hybridization between the molecular orbitals and the wave function of the substrate. For an upright-standing multilayer film, we observed the two-dimensional intermolecular band dispersion, which originates from the intermolecular π-π interaction. The observed effective masses of the hole for different azimuths demonstrate the presence of the anisotropy of the hole mobility in pentacene crystals also at higher temperatures.

Electronic structures of the ionic liquids formed by 1-buthyl-3-alkylimidazolium ion [Cnmim]+ (n = 4, 8, 10) with fluorine-containing anions (tetrafluoroboronate BF 4 - , hexafluorophosphate PF 6 - ) were studied by ultraviolet photoemission spectroscopy (UPS), inverse photoemission spectroscopy (IPES), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Comparison of the calculated density of states with the observed spectra has revealed that the energies of the molecular orbitals of these ionic liquids are significantly affected by the electrostatic Madelung potential among the ions, by which the top of the occupied states and the bottom of the unoccupied states are both derived from the cation.

地質構造の論理モデルは，地層の分布域を面で表現する数式や地層と面の関係を表す関係表で表現されてきた．本稿では論理モデルをラベルつき2分木で図式表現する方法を提案する．根は考察の対象となる領域を表す．枝点は面によって境された領域を表す．枝点からのびる2つの枝が一つの面による領域の2分割を表す．先端の葉で個々の地層の分布域を表す．全領域を表す根から地層の分布域を表す葉に至る枝につけたラベルで地層と面の関係を表す．2分木で表現可能な論理モデルに関しては，図式表現と関係表は同等であり，一方から他方へ情報の損失なく変換できる．堆積作用と侵食作用によって形成される地質構造の論理モデルについては，その帰納的定義に基づく機械的手続きにより，図式表現を導くことができる．図式表現は，論理モデルで表現された地質構造の性質，あるいは領域内の点に地層を対応づける関数などの3次元地質モデリングにかかわる基礎的概念の理解を助ける小道具として有効である．

The electronic structure at the interface formed between an organic film and a metal electrode plays a crucial role in the performance of electronic devices using organic semiconductors such as electroluminescent displays (light-emitting diodes), field-effect transistors, and photovoltaic cells. In particular, the energies of the highest-occupied and lowest-unoccupied molecular orbitals relative to the Fermi level of metals, i.e., the energy level alignment at organic/metal interfaces, are of fundamental importance in discussing the barrier heights for the charge injection and separation at the interface. However, it is generally not easy to discuss the interfacial electronic structure precisely since the interface energetics is usually modified due to various interface-specific phenomena. In this article, we introduce the recent progress in studies of the energy level alignment at organic/metal interfaces: (1) basic understanding, (2) interface dipole layer, and (3) interface states.

The root systems appearing in the theory of Lie superalgebras and Nichols algebras admit a large symmetry extending properly the one coming from the Weyl group. Based on this observation we set up a general framework in which the symmetry object is a groupoid. We prove that in our context the groupoid is generated by simple reflections and Coxeter relations. In a broad sense this answers a question of Serganova. Our weak version of the exchange condition allows us to prove Matsumoto’s theorem. Therefore the word problem is solved for the groupoid.

Angle-resolved photoelectron spectra were measured for a well-ordered monolayer film of titanyl phthalocyanine (OTiPc) prepared on a cleaved graphite surface using synchrotron radiation. The observed photoelectron angular distributions were analyzed by a calculation using the single-scattering approximation combined with molecular orbital calculation. The molecular orientation of the OTiPc monolayer on graphite was estimated quantitatively.

In this paper, we give a classification of the finite dimensional irreducible representations of a nonstandard quantum group U, which may be viewed as a Z/3Z-graded version of a quantum superalgebra.

A 1D metallic surface state was created on an anisotropic InSb(001) surface covered with Bi. Angle-resolved photoelectron spectroscopy (ARPES) showed a 1D Fermi contour with almost no 2D distortion. Close to the Fermi level (E_{F}), the angle-integrated photoelectron spectra showed power-law scaling with the binding energy and temperature. The ARPES plot above E_{F}, obtained thanks to a thermally broadened Fermi edge at room temperature, showed a 1D state with continuous metallic dispersion across E_{F} and power-law intensity suppression around E_{F}. These results strongly suggest a Tomonaga-Luttinger liquid on the Bi/InSb(001) surface.

A superlattice of strained Au-Si atomic wires is successfully fabricated on a Si surface. Au atoms are known to incorporate into the stepped Si(111) surface to form a Au-Si atomic wire array with both one-dimensional (1D) metallic and antiferromagnetic atomic chains. At a reduced density of Au, we find a regular array of Au-Si wires in alternation with pristine Si nanoterraces. Pristine Si nanoterraces impose a strain on the neighboring Au-Si wires, which modifies both the band structure of metallic chains and the magnetic property of spin chains. This is an ultimate 1D version of a strained-layer superlattice of semiconductors, defining a direction toward the fine engineering of self-assembled atomic-scale wires.

The hole-vibration coupling of the highest occupied state in pentacene thin films on graphite was studied by high-resolution ultraviolet photoemission spectroscopy. It was found that vibration satellites in the film are more intense than that in the gas phase and the vibrational energy in the film is slightly lower than that in the gas phase. This demonstrates that the reorganization energy (hole mobility) in the pentacene thin film is slightly larger (smaller) than that expected from the photoemission spectrum of free pentacene molecules.

Angle-resolved photoelectron spectra were measured for a single-domain monolayer film of naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA) prepared on a cleaved GeS(0 0 1) surface using synchrotron radiation. The observed photoelectron angular distributions were analyzed by a calculation using the single-scattering approximation combined with molecular orbital calculation. With the help of the low-energy electron diffraction pattern, the structure of the NTCDA monolayer on GeS(0 0 1) was estimated quantitatively.