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Rapid monitoring of large earthquakes, associated tsunamis, volcanic eruptions, and other phenomena is extremely important for understanding the underlying phenomena, as well as for disaster prevention and mitigation. In Japan, the Geospatial Information Authority of Japan (GSI) operates a continuous nationwide GNSS network (GEONET) across Japan. Based on the lessons learned from the 2011 Tohoku-Oki earthquake, the GSI and Graduate School of Science, Tohoku University, have jointly developed a new crustal deformation analysis system using GEONET data for quasi real-time earthquake size estimation, known as the GEONET analysis system for rapid deformation monitoring (REGARD) (Kawamoto et al.2016, 2017). The results of REGARD is used by the JMA as supporting information when issuing tsunami warnings/advisories. The fault models of REGARD were also adopted as sources to estimate tsunami inundation, and resulting damage. The system has been adopted as part of the Disaster Information Systems (DIS) operated by Japan’s Cabinet Office (Musa et al.2018; Ohta et al.2018) and will use the generated information for the initial governmental response after tsunamigenic earthquakes.In the presentation, the roles of real-time GNSS in disaster prevention and mitigation will be discussed, focusing on these developments of REGARD and others., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

While 12 years have already passed since the 2011 Tohoku-oki earthquake (M9.0), postseismic deformation of the earthquake is still ongoing. In order to detect the postseismic deformation of the Tohoku-oki earthquake, we have been performing repeating observations at seafloor sites for the GNSS-Acoustic (GNSS-A) geodetic observation technique since 2012 using both manned research vessels and an unmanned surface vehicle, called Wave Glider (WG), as a sea surface platform. We developed and tested a system to conduct the GNSS-A observations using the WG in 2019 and have continuously operated the system twice a year since 2020, visiting many (around 15) observation sites. Based on the observation data collected using research vessels and the WG, we estimated the displacement time series of the seafloor transponder array of each site. The spatio-temporal variations in seafloor crustal deformation after the 2011 Tohoku-oki earthquake indicate that the viscoelastic relaxation is the primary cause of the westward motion around the main rupture area of the M9 event, while the afterslip on the shallow plate interface played an important role in producing eastward displacements in the region south to the main rupture area. With respect to the region north to the main rupture area, no distinct spatial deformation pattern has been observed. This implies that multiple factors, i.e., viscoelastic relaxation, afterslip, interplate locking, and episodic slow slip events, are responsible for the complicated spatial deformation in this region. We will also report the current conditions of the equipment for GNSS-A observations in the presentation., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

An extensive seismic swarm, as well as transient deformation, have continued since the end of November 2020 in the Noto Peninsula, central Japan, which is a non-volcanic/geothermal area far from the major plate boundaries. We present the transient deformation clarified from a combined analysis of multiple GNSS observation networks, seismicity, and their interpretation. We analyzed data at 30 continuous GNSS stations operated by SoftBank Corp., the Geospatial Information Authority of Japan (GSI), and universities. The total displacement pattern for two years shows horizontal inflation and uplift up to ~70 mm around the source of the earthquake swarm. In the first three months, the opening of the low-angle tensile crack is estimated with a volumetric increase of ~1.4 x 107 m3 at a depth of ~16 km. In the next 15 months, the observed deformation is well reproduced by shear-tensile sources, which suggests an aseismic reverse-type slip and expansion of a southeast-dipping fault zone at a depth of 14-16 km. The estimated shear-tensile sources locate at the downdip of the clusters of the earthquake swarm. We interpreted our deformation model and earthquake sequence as follows. Upwelling fluid sub-horizontally spread in a southeast-dipping fault zone. And they migrated up-dip along the fault zone and caused sub-meter aseismic slip below the seismogenic depth. The aseismic slip further triggered intensive earthquakes above the seismogenic depth.Acknowledgments: We are grateful to SoftBank Corp., ALES Corp., and GSI for providing us with GNSS observation data. This work was supported byJSPS KAKENHI Grant Number JP22K19949., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The future of work has become a prominent topic for research and policy debate. However, the debate has focused entirely on paid work, even though people in industrialized countries on average spend comparable amounts of time on unpaid work. The objectives of this study are therefore (1) to expand the future of work debate to unpaid domestic work and (2) to critique the main methodology used in previous studies. To these ends, we conducted a forecasting exercise in which 65 AI experts from the UK and Japan estimated how automatable are 17 housework and care work tasks. Unlike previous studies, we applied a sociological approach that considers how experts’ diverse backgrounds might shape their estimates. On average our experts predicted that 39 percent of the time spent on a domestic task will be automatable within ten years. Japanese male experts were notably pessimistic about the potentials of domestic automation, a result we interpret through gender disparities in the Japanese household. Our contributions are providing the first quantitative estimates concerning the future of unpaid work and demonstrating how such predictions are socially contingent, with implications to forecasting methodology.

Using the density-functional-theory based electronic structure calculations, we study the electronic state of recently discovered mixed-valent manganese oxides $A$Mg$_4$Mn$_6$O$_{15}$ ($A=$ K, Rb, Cs), which are fully spin-polarized ferromagnetic insulators with a cubic crystal structure. We show that the system may be described as a three-dimensional arrangement of the one-dimensional chains of a $2p$ orbital of O and a $3d$ orbital of Mn running along the three axes of the cubic lattice. We thereby argue that in the ground state the chains are fully spin polarized due to the double-exchange mechanism and are distorted by the Peierls mechanism to make the system insulating., Comment: 5 pages, 5 figures

We analyze the measured optical conductivity spectra using the density-functional-theory-based electronic structure calculation and density-matrix renormalization group calculation of an effective model. We show that, in contrast to a conventional description, the Bose-Einstein condensation of preformed excitons occurs in Ta$_2$NiSe$_5$, despite the fact that a noninteracting band structure is a band-overlap semimetal rather than a small band-gap semiconductor. The system above the transition temperature is therefore not a semimetal, but rather a state of preformed excitons with a finite band gap. A novel insulator state caused by the strong electron-hole attraction is thus established in a real material., Comment: 5 pages, 4 figures, Supplemental Material

We discuss herein the emergence of a large entropy change in metallic Li0.33VS2 derived from the orbitally assisted loose �� bond formation. Comprehensive structural studies based on synchrotron x-ray and neutron diffraction analyses clarify the fabrication of ribbon chains at 375 K, consisting of multiple three-centered two-electron �� bonds based on the viewpoint of local chemical bonding. Although the metallic conductivity persists down to the lowest temperature measured, exceptionally large entropy change as a metal, as much as ��S = 6.6 J/mol K, appears at the transition. Emergence of a large entropy change in a metallic state expects us the possible novel functional materials, such as a heat-storage material with rapid thermal response., 6 pages, 4 figures, to be published in Phys. Rev. B: Rapid Communications

The identification of structured state-space model has been intensively studied for a long time but still has not been adequately addressed. The main challenge is that the involved estimation problem is a non-convex (or bilinear) optimization problem. This paper is devoted to developing an identification method which aims to find the global optimal solution under mild computational burden. Key to the developed identification algorithm is to transform a bilinear estimation to a rank constrained optimization problem and further a difference of convex programming (DCP) problem. The initial condition for the DCP problem is obtained by solving its convex part of the optimization problem which happens to be a nuclear norm regularized optimization problem. Since the nuclear norm regularized optimization is the closest convex form of the low-rank constrained estimation problem, the obtained initial condition is always of high quality which provides the DCP problem a good starting point. The DCP problem is then solved by the sequential convex programming method. Finally, numerical examples are included to show the effectiveness of the developed identification algorithm., Accepted to IEEE Conference on Decision and Control (CDC) 2015

The origin of successive phase transitions observed in the layered perovskite $��$-Sr$_2$CrO$_4$ is studied by the density-functional-theory-based electronic structure calculation and mean-field analysis of the proposed low-energy effective model. We find that, despite the fact that the CrO$_6$ octahedron is elongated along the $c$-axis of the crystal structure, the crystal-field level of nondegenerate $3d_{xy}$ orbitals of the Cr ion is lower in energy than that of doubly degenerate $3d_{yz}$ and $3d_{xz}$ orbitals, giving rise to the orbital degrees of freedom in the system with a $3d^2$ electron configuration. We show that the higher (lower) temperature phase transition is caused by the ordering of the orbital (spin) degrees of freedom., 5 pages, 5 figures; J. Phys. Soc. Jpn., in press

OBJECTIVE To evaluate the effect of barnidipine hydrochloride, a long-acting dihydropyridine calcium channel blocker on urinary sodium excretion in patients with essential hypertension. PATIENTS Twelve patients (2 males, 10 females) with mild to moderate essential hypertension. METHODS A single-blinded study. After the control (placebo) period, 10 to 15 mg barnidipine hydrochloride was administered for 7 days, followed by a post-treatment (placebo) period. Daily changes in blood pressure, urinary volume, and urinary electrolyte excretions were evaluated. Plasma levels of atrial natriuretic peptide (ANP) and aldosterone were also determined in each period. Daily sodium intake was kept at 120 mEq. RESULTS Blood pressure decreased from 161 +/- 4/92 +/- 2 mmHg to 146 +/- 4/85 +/- 2 mmHg (p

BACKGROUND There is a general agreement that a preferential accumulation of alloantigens within the liver could induce hyporesponsiveness to the inoculated antigens. Entrapment of antigens in the liver may evoke an unique immune response in the organ and play a key role in determination of the fate of the transplanted grafts. To understand the immune response in the liver after inoculation of allogeneic donor antigens, we examined the immune response to systemically inoculated alloantigen in rats whose sensitized liver was replaced with that of naive rats or in naive rats whose liver was replaced with that of sensitized rats. METHODS Using implantation of syngeneic liver (alloantigen-accumulated/naive) in rats (naive/alloantigen-sensitized), we compared the immune responses to alloantigen between rats with hepatic/extrahepatic alloantigen at 24 hr after alloantigen inoculation. This was called sensitized-liver-grafted (SLG)/sensitized-liver-removed (SLR) treatment. The immune response to donor alloantigen in this model was evaluated by survival of skin or heart grafts, complement-dependent cytotoxicity (CDC) titer and delayed-type hypersensitivity (DTH) response. RESULTS Compared with the mean survival time (MST) in donor spleen cell inoculated (DSI) rats (skin and heart, MST: 8.2+/-1.1 and 10.7+/-2.3 days), SLG rats rejected allografts in an accelerated fashion (skin and heart, MST: 5.5+/-0.5 and 4.2+/-0.8 days), associated with higher CDC titer and DTH response. In contrast, allograft survival was moderately prolonged in SLR (skin and heart, MST: 16.5+/-2.6 and 29.5+/-3.7 days) associated with suppressed CDC titer and DTH response. The survival of third-party allograft after SLG or SLR treatment (skin, MST: 9.3+/-1.5 or 9.7+/-0.6 days) indicated that immunological hyper/hyporesponsiveness was donor-specific. CONCLUSIONS A strong anti-donor immune response was induced by the transfer of donor antigen-baring liver to naive rats 24 hr after alloantigen inoculation, whereas removal of the liver suppressed alloimmune response. Our results indicate that vigorous anti-alloimmune response occurred in the liver after systemic inoculation of donor spleen cells.

BACKGROUND Rejection of pancreatic islet grafts is still a serious problem. We evaluated the effect of mitomycin C (MMC) on the survival of crude islets grafts after xenogeneic islet transplantation. METHODS WS (RT1k) rat islets pretreated with various concentrations of MMC (0, 1, 3.2, 10, 32, 50, 100, 320, and 1,000 microg/ml) were transplanted into C57BL/6 mice with streptozotocin-induced diabetes. In vivo graft function was assessed by a daily measurement of nonfasting blood glucose concentration in each animal. We also examined the separate effect of MMC on purified islets and contaminants present in the crude islet preparation. RESULTS MMC at doses of 10, 32, 50, and 100 microg/ml resulted in a significant prolongation of the mean graft survival time from a control of 12.4+/-2.5 days to 23+/-7.4, 17.5+/-5.4, 25.5+/-14.7, and 26.7+/-8.9 days, respectively. Deterioration of glucose metabolism was noted when the dose exceeded 32 microg/ml, whereas at 320 microg/ ml, MMC failed to restore normoglycemia. Prolongation of survival time of crude islets was the result of its effect on islets and contaminant components of the crude islet preparation. In vitro study showed that MMC treatment at a higher concentration than 10 microg/ml reduces the stimulatory as well as proliferative capacity of lymph node cells. CONCLUSIONS Pretreatment of pancreatic islets with MMC at 10 microg/ml prolongs xenograft survival without deterioration of in vivo graft function. This novel treatment modality represents a new strategy for the modulation of immunity of islets and contaminants in crude islet preparations.

Cellular interactions that lead to graft rejection were examined in a rat-to-mouse xenogeneic combination using species-specific monoclonal antibodies (mAbs) against donor and recipient intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) molecules, respectively. Although both mAbs displayed moderate blocking activity in an in vitro mixed lymphocyte response assay, strong suppression was observed when anti-donor (rat) ICAM-1 mAb was combined with anti-recipient (mouse) LFA-1 mAb. Likewise, significant prolongation of islet xenograft survival was observed with these mAbs. Thus, 0.05 mg of anti-mouse LFA-1 mAb and anti-rat ICAM-1 mAb given on days 0 and 1 produced significant prolongation of graft survival over the control (51+/-20 days vs. 10+/-3 days, P

Summary Fas ligand (FasL) is highly expressed in testicular tissues and thought to be responsible for protection from allograft rejection by inducing apoptosis of anti-graft activated T cells. FasL-expressing islets have been shown to induce a granulocyte-mediated inflammatory reaction. We investigated whether a graft can be protected from alloimmune responses by manipulating the Fas/FasL-system. We transplanted allogeneic islets under the kidney capsule of streptozotocin-induced diabetic mice together with testicular tissue. Significant prolongation of survival of C3H islet allograft was observed in C57BL/6 (B6) recipients transplanted with C3H testicular tissue, but not in those transplanted with C3H-gld testicular tissue expressing non-functional FasL. No significant prolongation was observed in B6-lpr recipients expressing non-functional Fas. Immunohistochemical staining of C3H testicular tissue in the composite graft showed a high expression of FasL, but not that of the C3H-gld testicular tissue. In situ terminal deoxynucleotidyl transferase-mediated dUDP-biotin catalysed DNA nick-end labelling (TUNEL) staining of a composite graft of C3H islet and testicular tissue in B6 recipients demonstrated extensive apoptosis of infiltrating mononuclear cells around the graft. The protective effect of C3H testicular tissue was abrogated when anti-FasL monoclonal antibody was administered i. p. postoperatively. Our results suggest that FasL-positive testicular allografts protect composite islet allografts and indicate that manipulation of Fas/ FasL mediated apoptosis is a suitable strategy for controlling rejection of islet allografts. [Diabetologia (1998) 41: 315‐321]

Background. Antiadhesion therapy using monoclonal antibodies (mAbs) to adhesion molecules in vivo has been shown to produce significant prolongation of graft survival in various transplantation models. However, it remains unclear whether antiadhesion therapy operates by merely blocking adhesion between antigen-presenting cells and T cells physically and/or by blocking costimulatory signals while preserving signals mediated through T-cell receptors in vivo. We examined antigen-specific T-cell responses during and after antiadhesion therapy. Methods. BALB/c islets were transplanted into the renal subcapsular space of streptozotocin-induced diabetic C57BL/6 mice given anti-lymphocyte function-associated antigen (LFA)-1 and/or anti-intercellular adhesion molecule-1 mAb treatment. The animals bearing surviving islet allografts were challenged with BALB/c or third-party islets on day 7 or more than 100 days after transplantation. Results. Islet allografts were acutely rejected in untreated animals, with a mean survival time (MST) of 19+8 days. Administration of anti-LFA-1 mAb induced significant prolongation of graft survival with a mean survival time of 72+33 days, and half of the allografts showed indefinite survival. The animals given anti-LFA-1 mAb alone 7 days before transplantation showed acute rejection of BALB/c islets, whereas a significant number of animals given anti-LFA-1 mAb and the BALB/c islet allograft simultaneously accepted secondary BALB/c islets, but rejected third-party islets. Likewise, most of the animals bearing long-term functioning BALB/c allografts for more than 100 days accepted secondary BALB/c islets, but rejected C3H islets acutely. Interestingly, the spleen cells from these animals transferred unresponsiveness to BALB/c islets into the 2.5-Gy x-irradiated recipients, whereas those from naive animals induced acute rejection. Conclusions. These results indicate that anti-LFA-1 mAb treatment prevents T-cell activation leading to rejection, but results in a T-cell receptor engagement leading to antigen-specific unresponsiveness maintained by transferrable suppressor cells.

We have previously reported that a physiological range of shear stress induces neutrophil homotypic aggregation mediated by lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-3 (ICAM-3) interactions. To further characterized the homotypic aggregation, actin polymerization was investigated in neutrophils stimulated by shear stress in comparison with formyl-methionyl-leucyl-phenylalanine (fMLP). In fMLP-stimulated neutrophils, actin polymerization was localized in the pseudopods, and this reaction was not mediated by a cytosolic level of Ca2+. In contrast to fMLP stimulation, the actin polymerization induced by shear stress in a cone-plate viscometer was localized in cell-cell contact regions, and this polymerization required the increase of intracellular Ca2+. This shear stress-induced actin polymerization was not observed when neutrophils were pretreated with anti-LFA-1 or anti-ICAM-3 antibody. In conclusion, LFA-1 and ICAM-3 interaction mediated by the increase of [Ca2+]i generated the intercellular signal in order to accumulate F-actin in the cell-cell contact regions.

Recent remapping and new age determinations has shed light on the understanding of Precambrian rocks northwest of Hornsund, southwest Spitsbergen. The Skålfjellet Subgroup has been regarded as the eastern equivalent of the Vimsodden Subgroup, and both of these occur within the Precambrian Eimfjellet Group of southwest Spitsbergen. Although the Eimfjellet Group is considered to be older than the oldest unconformity in the area, the age of the rocks has not been known. The granitic-gabbroic rocks in the Skålfjellet Subgroup have been considered to be the products of granitisation for many years, but recent observations show that they are exotic blocks incorporated into the basic eruptive rocks which are the main constituents of the subgroup. These plutonic rocks have a wide range of compositions, from syenite via granite to gabbroic cumulates, which suggests the existence of a well-differentiated plutonic body at depth. U-Pb zircon and Pb evaporation datings yielded magmatic ages of ca. 1,100 to 1,200 Ma, and a conformable age has been obtained by Rb-Sr whole rock dating. Detrital zircons from the micaceous schists of the Isbjørnhamna Group, which underlies the Skålfjellet Subgroup, show a poorly defined discordia with an upper intercept age of ca. 2,200 Ma and a lower intercept age of ca. 360 Ma. These dating results define the magmatic age of the granitic-gabbroic rocks as late Mesoproterozoic, early Grenvillian. This age is in broad agreement with that of the metavolcanic rock clasts of the Pyttholmen meta-pyroclastic-conglomeratic unit at Vimsodden, which is considered to be the westernmost occurrence of the Skålfjellet Subgroup. A Rb-Sr whole rock age determination of the shaly phyllites from the Deilegga Group was performed in order to place constraints on the age of younger Precambrian event; however, no good isochron was obtained.

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Using the band structure calculation and mean-field analysis of the derived three-chain Hubbard model with phonon degrees of freedom, we discuss the origin of the orthorhombic-to-monoclinic phase transition of the layered chalcogenide Ta$_2$NiSe$_5$. We show that the Bose-Einstein condensation of excitonic electron-hole pairs cooperatively induces the instability of the phonon mode at momentum $q\rightarrow 0$ in the quasi-one-dimensional Ta-NiSe-Ta chain, resulting in the structural phase transition of the system. The calculated single-particle spectra reproduce the deformation of the band structure observed in the angle-resolved photoemission spectroscopy experiment., Comment: 5 pages, 4 figures

We present an exact diagonalization study of the self-energy of the two-dimensional Hubbard model. To increase the range of available cluster sizes we use a corrected t-J model to compute approximate Greens functions for the Hubbard model. This allows to obtain spectra for clusters with 18 and 20 sites. The self-energy has several `bands' of poles with strong dispersion and extended incoherent continua with k-dependent intensity. We fit the self-energy by a minimal model and use this to extrapolate the cluster results to the infinite lattice. The resulting Fermi surface shows a transition from hole pockets in the underdoped regime to a large Fermi surface in the overdoped regime. We demonstrate that hole pockets can be completely consistent with the Luttinger theorem. Introduction of next-nearest neighbor hopping changes the self-energy stronlgy and the spectral function with nonvanishing next-nearest-neighbor hopping in the underdoped region is in good agreement with angle resolved photoelectron spectroscopy., Comment: 17 pages, 18 figures

Synchrotron X-ray diffraction experiment shows that the metal-insulator transition occurring in a ferromagnetic state of a hollandite K$_2$Cr$_8$O$_{16}$ is accompanied by a structural distortion from the tetragonal $I4/m$ to monoclinic $P112_{1}/a$ phase with a $\sqrt{2}\times\sqrt{2}\times 1$ supercell. Detailed electronic structure calculations demonstrate that the metal-insulator transition is caused by a Peierls instability in the quasi-one-dimensional column structure made of four coupled Cr-O chains running in the $c$-direction, leading to the formation of tetramers of Cr ions below the transition temperature. This furnishes a rare example of the Peierls transition of fully spin-polarized electron systems., Comment: Phys. Rev. Lett., in press, 5 pages, 3 figures

The ground-state properties of the three-leg S=3/2 Heisenberg tube are studied using the density-matrix renormalization group method. We find that the spin-excitation gap associated with a spontaneous dimerization opens for the whole coupling regime, as seen in the three-leg S=1/2 Heisenberg tube. However, in contrast to the case of S=1/2 tube, the gap increases very slowly with increasing the rung coupling and its size is only a few % or less of the leg exchange interaction in the weak- and intermediate-coupling regimes. We thus argue that, unless the rung coupling is substantially larger than the leg coupling, the gap may be quite hard to be observed experimentally. We also calcuate the quantized Berry phase to show that there exist three kinds of valence-bond-solid states depending on the ratio of leg and rung couplings., Comment: 4 pages, 5 figures

Mott transition and ferrimagnetism are studied in the Hubbard model on the anisotropic kagom�� lattice using the variational cluster approximation and the phase diagram at zero temperature and half-filling is analyzed. The ferrimagnetic phase rapidly grows as the geometric frustration is relaxed, and the Mott insulator phase disappears in moderately frustrated region, showing that the ferrimagnetic fluctuations stemming from the relaxation of the geometric frustration is enhanced by the electron correlations. In metallic phase, heavy fermion behavior is observed and mass enhancement factor is computed. Enhancement of effective spatial anisotropy by the electron correlations is also confirmed in moderately frustrated region, and its effect on heavy fermion behavior is examined., 5 pages, 6 figures

Based on the first-principles electronic structure calculations, we predict that a chromium oxide K$_2$Cr$_8$O$_{16}$ of hollandite type should be a half-metallic ferromagnet where the Fermi level crosses only the majority-spin band, whereas the minority-spin band has a semiconducting gap. We show that the double-exchange mechanism is responsible for the observed saturated ferromagnetism. We discuss possible scenarios of the metal-insulator transition observed at low temperature and we argue that the formation of the incommensurate, long-wavelength density wave of spinless fermions caused by the Fermi-surface nesting may be the origin of the opening of the charge gap., Comment: 7 pages, 7 figures; minor modifications; Phys. Rev. B, in press

We consider electronic properties of hollandite vanadate K$_2$V$_8$O$_{16}$, a one-dimensional zigzag-chain system of $t_{2g}$ orbitals in a mixed valent state. We first calculate the Madelung energy and obtain the relative stability of several charge-ordering patterns to determine the most stable one that is consistent with the observed superlattice structure. We then develop the strong-coupling perturbation theory to derive the effective spin-orbit Hamiltonian, starting from the triply-degenerate $t_{2g}$ orbitals in the VO$_6$ octahedral structure. We apply an exact-diagonalization technique on small clusters of this Hamiltonian and obtain the orbital-ordering pattern and spin structures in the ground state. We thereby discuss the electronic and magnetic properties of K$_2$V$_8$O$_{16}$ including predictions on the outcome of future experimental studies., Comment: 7 pages, 8 figures

An \textit{ab initio} electronic structure calculation based on the generalized gradient approximation in the density functional theory is carried out to study the basic electronic states of hollandite vanadate K$_2$V$_8$O$_{16}$. We find that the states near the Fermi energy consist predominantly of the three $t_{2g}$-orbital components and the hybridization with oxygen $2p$ orbitals is small. The $d_{yz}$ and $d_{zx}$ orbitals are exactly degenerate and are lifted from the $d_{xy}$ orbital. The calculated band dispersion and Fermi surface indicate that the system is not purely one-dimensional but the coupling between the VO double chains is important. Comparison with available experimental data suggests the importance of electron correlations in this system., Comment: 5 pages, 5 figures

Using the Lanczos exact-diagonalization and density-matrix renormalization group methods, we study the extended Hubbard model at quarter filling defined on the anisotropic triangular lattice. We focus on charge ordering (CO) phenomena induced by onsite and intersite Coulomb interactions. We determine the ground-state phase diagram including three CO phases, i.e., diagonal, vertical, and three-fold CO phases, based on the calculated results of the hole density and double occupancy. We also calculate the dynamical density-density correlation functions and find possible coexistence of the diagonal and three-fold charge fluctuations in a certain parameter region where the onsite and intersite interactions compete. Furthermore, the characteristic features of the optical conductivity for each CO phase are discussed., 9 pages, 7 figures

As a part of the Norwegian Antarctic Research Expedition 1984/85, geological mapping was performed in Gjelsvikfjella and western Mühlig-Hofmannfjella, Dronning Maud Land. The northern part of Gjelsvikfjella is dominated by the Jutulsessen metasupracrustals which have been intruded by a major gabbroic body and several generations of dykes. To the south the metasupracrustals gradually transform into the Risemedet migmatites. In western Mühlig-Hofmannfjella the bedrock is dominated by the large Svarthamaren Charnockite batholith. The batholith is bordered by the Snøtoa metamorphic complex outcropping to the south and west in Mühlig-Hofmannfjella and it is characterized by a high content of partly assimilated country rock inclusions. Mineral paragenesis and geothermometry/geobarometry suggest a two-stage tectonothermal-igneous history with an initial intermediate pressure, upper amphibolite to granulite facies metamorphism followed by high temperature transformations related to the charnockite intrusion. The age of the initial tectonothermal event is probably about 1,100 Ma. Geochronological work in the present study (Rb/Sr whole rock) gave an age of 500 ± 24 Ma for the Svarthamaren Charnockite, interpreted to record the age of crystallization. Late brittle faulting and undeformed dolerite dykes outcropping in Jutulsessen are believed to be related to Mesozoic crustal stretching in the Jutulstraumen-Pencksøkket Rift Zone to the west.

There are still difficulties in determining the risk of recurrence to decide whether to perform selective adjuvant treatment for stage I non-small cell lung cancer. This study reviewed 122 stage I patients who underwent curative surgery to assess the usefulness of an angiogenesis-associated factor as a predictor of recurrence. By immunohistochemical examination, we collected information about tumor-induced vascular endothelial growth factor (VEGF)-A and -C expression at the primary site. During the median follow-up period of 120 months, the overall 10-year survival rate was 53.5%. The 10-year survival rates according to VEGF-A/C expression were as follows: VEGF-A high/VEGF-C high group, 26.0%; VEGF-A high/VEGF-C low group, 42.7%; VEGF-A low/VEGF-C high group, 73.1%; VEGF-A low/VEGF-C low group, 65.1%. The VEGF-A high/VEGF-C high group showed the worst outcome. The diagnostic values of the marker combination for predicting recurrence were as follows: sensitivity, 71.4%; specificity, 63.8%; and accuracy, 65.6%. When stratified by T factor, preferable high values for both negative predictive value and specificity were obtained in patients with stage IA disease. In order to select the patients eligible for selective adjuvant therapy at early stages, especially in stage IA disease, simultaneous assessment of tumor-induced VEGF-A/C warrants further study.

Quantum Monte Carlo (QMC) and density-matrix renormalization group (DMRG) methods are used to study the coupled spin-pseudospin Hamiltonian in one-dimension (1D) that models the charge-ordering instability of the anisotropic Hubbard ladder at quarter filling. We calculate the temperature dependence of the uniform spin susceptibility and specific heat as well as the spin and charge excitation spectra of the system. We show that there is a parameter and temperature region where the spin degrees of freedom are separated from the charge degrees of freedom and behave like a 1D antiferromagnetic Heisenberg model, and that, outside this parameter region and above a crossover temperature, the spin excitations are largely affected by the charge fluctuation. We argue that observed anomalous spin dynamics in the disorder phase of a typical charge-ordered material $\alpha'$-NaV$_2$O$_5$ may possibly be a consequence of this type of spin-charge coupling., Comment: 7 pages, 8 eps figures

We apply the algebraic-geometric techniques developed for the study of mappings which have the singularity confinement property to mappings which are integrable through linearisation. The main difference with respect to the previous studies is that the linearisable mappings have generically unconfined singularities. Despite this fact we are able to provide a complete description of the dynamics of these mappings and derive rigorously their growth properties., Comment: 20 pages, 8 figures

Unlike all other vertebrates examined to date, there is only one detectable class I locus in the Xenopus MHC. On the bases of a nearly ubiquitous and high tissue expression, extensive polymorphism, and MHC linkage, this gene is of the classical or class Ia type. Sequencing analysis of class Ia cDNAs encoded by eight defined MHC haplotypes reveals two very old allelic lineages that perhaps emerged when humans and mice diverged from a common ancestor up to 100 million years ago. The unprecedented age of these lineages suggests that different class Ia genes from ancestors of the laboratory model Xenopus laevis are now expressed as alleles in this species. The lineages are best defined by their cytoplasmic and alpha2 peptide-binding domains, and there are highly diverse alleles (defined by the alpha1 peptide-binding domain) in each lineage. Surprisingly, the alpha3 domains are homogenized in both lineages, suggesting that interallelic gene conversion/recombination maintains the high sequence similarity.

We examine the validity of the results obtained with the singularity confinement integrability criterion in the case of discrete Painlev�� equations. The method used is based on the requirement of non-exponential growth of the homogeneous degree of the iterate of the mapping. We show that when we start from an integrable autonomous mapping and deautonomise it using singularity confinement the degrees of growth of the nonautonomous mapping and of the autonomous one are identical. Thus this low-growth based approach is compatible with the integrability of the results obtained through singularity confinement. The origin of the singularity confinement property and its necessary character for integrability are also analysed., PlainTeX

We present an exact diagonalization study of the single particle spectral function in the 1D and 2D t-J model. By studying the scaling properties with J and t we find a simple building pattern in 1D and show that every spectral feature can be uniquely assigned by a spinon and holon momentum. We find two types of low energy excitations: a band with energy scale J and high spectral weight disperses upwards in the interior part of the Brillouin zone and reaches E_F at k_F, and a band with energy scale t and low spectral weight disperses downwards in the outer part of the zone, touching E_F at 3k_F. An analogous analysis of the 2D case at half filling shows that the t-band exists also in this case, but is diffuse and never reaches the Fermi energy. For the doped case in 2D the picture is more reminiscent of 1D, in particular the `main-band' with a dispersion proportional J and the `shadow band' with energy scale t can be identified also in this case. This leads us to propose that the shadow bands discovered by Aebi et al. in Bi2212 are the 2D analogue of the 3k_F singularity in 1D systems and unrelated to antiferromagnetic spin fluctuations., Comment: 9 pages, Revtex, with 10 eps figures. Hardcopies of figures (or the entire manuscript) can be obtained by e-mail request to eder@vsf1.phys.rug.nl

We study the momentum distribution function n(k) in the 2D t-J model on small clusters by exact diagonalization. We show that n(k) can be decomposed systematically into two components with Bosonic and Fermionic doping dependence. The Bosonic component originates from the incoherent motion of holes and has no significance for the low energy physics. For the Fermionic component we exlicitely perform the one-to-one Landau mapping between the low lying eigenstates of the t-J model clusters and those of an equivalent system of spin-1/2 quasiparticles. This mapping allows to extract the quasiparticle dispersion, statistics, and Landau parameters. The results show conclusively that the 2D t-J model for small doping is a Fermi liquid with a `small' Fermi surface and a moderately strong attractive interaction between the quasiparticles., Comment: Revtex file, 5 pages with 5 embedded eps-files, hardcopies of figures (or the entire manuscript) can be obtained by e-mail request to: eder@vsf1.phys.rug.nl

Smooth pursuit eye movements have strong modulating effects on perceived motion both temporally and spatially. Abrupt changes in the direction of a target cause non-veridical perceived velocity and trajectory pattern when a visual cues appear with the moving target. In addition, this condition of non-veridical velocity and trajectory perception increases no visual cues are presented. Non-veridical perception was also connected with target velocity: the more difficult the eye pursuit, the more frequent was the non-veridical perception.

We present the bilinear forms of the (continuous) Painlev�� equations obtained from the continuous limit of the analogous expresssions for the discrete ones. The advantage of this method is that it leads to very symmetrical results. A new and interesting result is the bilinearization of the P$_{\rm VI}$ equation, something that was missing till now., 9 pages, plainTeX

Three dimensional topological field theories associated with the three dimensional version of Abelian and non-Abelian Seiberg-Witten monopoles are presented. These three dimensional monopole equations are obtained by a dimensional reduction of the four dimensional ones. The starting actions to be considered are Gaussian types with random auxiliary fields. As the local gauge symmetries with topological shifts are found to be first stage reducible, Batalin-Vilkovisky algorithm is suitable for quantization. Then BRST transformation rules are automatically obtained. Non-trivial observables associated with Chern classes are obtained from geometric sector and are found to correspond to those of the topological field theory of Bogomol'nyi monopoles., new revised version, off-shell action is modified

Starting from integrable cellular automata we present a novel form of Painlev�� equations. These equations are discrete in both the independent variable and the dependent one. We show that they capture the essence of the behavior of the Painlev�� equations organizing themselves into a coalescence cascade and possessing special solutions. A necessary condition for the integrability of cellular automata is also presented., 8 pages, plainTeX, 2 figures

We show that there is a series of topological string theories whose integrable structure is described by the Toda lattice hierarchy. The monodromy group of the Frobenius manifold for the matter sector is an extension of the affine Weyl group $\widetilde W (A_N^{(1)})$ introduced by Dubrovin. These models are generalizations of the topological $CP^1$ string theory with scaling violation. The logarithmic Hamiltonians generate flows for the puncture operator and its descendants. We derive the string equation from the constraints on the Lax and the Orlov operators. The constraints are of different type from those for the $c=1$ string theory. Higher genus expansion is obtained by considering the Lax operator in matrix form., 27 pages, latex, no figures

Bilinear structure for the discrete Painlev�� I equation is investigated. The solution on semi-infinite lattice is given in terms of the Casorati determinant of discrete Airy function. Based on this fact, the discrete Painlev�� I equation is naturally extended to a discrete coupled system. Corresponding matrix model is also mentioned., 6 pages in LaTeX, to appear in Proceedings of the Workshop on Symmetries and Integrability of Difference Equations, CRM Proceedings and Lecture Notes Series, AMS, 1994

We present an exact diagonalization study of the dynamical spin and density correlation functions in small clusters of 2D t-J model for intermediate and low electron densities, rho, RevTex-file (4.5 PRB-pages) + 9 figures attached as compressed postscript files

A detailed exact-diagonalization study is made for the doping dependence of the single-particle spectral function $A({\bf k},\omega)$ and momentum distribution function $n({\bf k})$ of the two-dimensional $t$$-$$J$ model as a representative model for doped Mott insulators. The results for $A({\bf k},\omega)$ show unambiguously that the rigid-band behavior is realized in the small-cluster $t$$-$$J$ model: upon doping, the uppermost states of the quasiparticle band observed at half filling simply cross the Fermi level and reappear as the lowermost states of the inverse photoemission spectrum, while the photoemission side of the band remains essentially unaffected. We discuss problems in directly determining the Fermi surface from $n({\bf k})$ and make a situation where they are largely avoided; we then find clear signatures of a Fermi surface which takes the form of small hole pockets. The identical scaling with $t/J$ of the quasiparticle weight $Z_h$ and difference in $n({\bf k})$ between neighboring ${\bf k}$-points suggests the existence of such a Fermi surface in the physical regime of parameters. We construct spin-bag operators which describe the holes dressed by the antiferromagnetic spin fluctuations and find that elementary electronic excitations of the system can be described well in terms of weakly-interacting spin-1/2 Fermionic quasiparticles corresponding to the doped holes. We make a comparison with other numerical calculations and recent angle-resolved photoemission experiment and argue that, adopting this rather conventional Fermi-liquid scenario with non-Luttinger Fermi surface, one would explain many quasiparticle-relating properties of doped cuprates in a very simple and natural way. We also show that the dynamical spin and charge excitations deviate from the particle-hole excitations of this Fermi liquid: e.g., the dominant low-energy spin excitation at momentum transfer $(\pi,\pi)$ reflects excitations of the incoherent spin background and is identified as a collective mode comparable to spin waves in the Heisenberg antiferromagnet., Comment: 12 pages, PlainTex, hard copy with figures available upon request

Sleep apnea is often caused by obstruction of the pharyngeal airway. The goal of this study was to use ultrafast MR imaging to examine the pharyngeal airway in patients with sleep apnea and to evaluate the usefulness of this technique for localizing the site of obstruction.Fifteen patients with sleep apnea and five healthy volunteers underwent ultrafast MR imaging while awake and during sleep induced with hydroxyzine hydrochloride. Sequential midline sagittal images of the pharynx were obtained and displayed in the cine mode.Patients with sleep apnea were found to have sites of pharyngeal abnormality that were not present in healthy volunteers. Nine sites of narrowing in seven patients (47%) were detected with the patient awake; 21 sites of obstruction in 13 patients (87%) were diagnosed with the patient asleep. Six patients showed only one obstruction, and seven had several obstructions: five had obstructions at the velum palatinum and at the oropharynx; one had obstructions at the velum palatinum, oropharynx, and hypopharynx; one had obstructions at the velum palatinum and the hypopharynx. The sites of narrowing during wakefulness and the sites of obstruction during sleep were the same in only four (31%) of the patients with pharyngeal airway obstruction.Ultrafast MR imaging is useful for localizing the sites of pharyngeal airway obstruction in patients with sleep apnea.

The microvascular architecture of filiform papillae was investigated under a scanning electron microscope in man, Japanese monkeys, common squirrel monkeys, common marmosets, common tree shrews, large Japanese moles and dwarf shrews utilizing microvascular corrosion casts. Filiform papillae were circularly arranged in primates, and each of them was supplied by a hairpin capillary loop. These papillae sometimes were aggregated. The filiform papillae of Japanese monkeys exhibited markedly locational differences on the lingual dorsum and were supplied by circularly arranged capillary loops or by an intrapapillary capillary network. Small filiform papillae were located on an epithelial eminence in the lingual radix, each of them supplied by a low and simple hairpin capillary loop. The aggregated filiform papillae of common squirrel monkeys were less frequent without any locational differences. Low filiform papillae of common marmosets and tree shrews were simpler in form, being arranged in a circle and supplied by a simple hairpin capillary loop. The filiform papillae of insectivores were not arranged in a circle. The filiform papillae of dwarf shrews were supplied by an incomplete capillary ring without a loop. With respect to species differences, the circularly arranged capillary loops in man were most complicated and highly developed. Microvascular architecture of the filiform papillae of insectivores was much simpler, different from those observed in primates.

Two populations of hematopoietic stem cells (HSC) in mouse bone marrow (BM) are defined on the basis of the presence or absence of interleukin- 3 (IL-3) receptor-associated antigen (IL-3RAA). HSC were purified by depletion of mature lymphoid-lineage cells followed by collection of the low-density fraction and sorting of wheat germ agglutinin-binding (WGA+) cells using a fluorescein-activated cell sorter. WGA+ cells were further separated into two populations (IL-3RAA+/WGA+ and IL-3RAA- /WGA+) by a monoclonal antibody (MoAb) against IL-3RAA. IL-3RAA+/WGA+ cells formed CFU-S on day 8; this population consisted mainly of cells in the cycling phase. IL-3RAA-/WGA+ cells form CFU-S on day 12; this population consisted mainly of dormant cells (cells in the G0 phase). When two populations obtained from C3H/HeN mice were injected into lethally irradiated (C57BL/6 x C3H/HeN)F1 mice, donor-derived cells in the peripheral blood (PB) appeared significantly earlier in mice injected with IL-3RAA+/WGA+ cells than in those injected with IL-3RAA- /WGA+ cells, whereas the reconstruction efficiency of IL-3RAA-/WGA+ cells had overtaken that of IL-3RAA+/WGA+ cells 6 weeks after injection. Long-term observation showed no significant difference between these two populations, however. The radioprotective ability (RPA) (30-day survival) of these two populations was therefore compared. The RPA of IL-3RAA-/WGA+ cells was significantly higher than that of IL-3RAA+/WGA+ cells. These findings therefore suggest that the former population is more primitive.

The present paper deals with the microvascular architecture of the palatine mucosa in primates, camivorae, and rodentia utilizing microvascular corrosion castings and epithelium-separated specimens. The submucous vascular network is under-developed since the bard palatine mucosa was designated the mucoperiosteum, except some areas. The palatine venous plexus appears to show regional differences with animal species differences. The well-developed plexus is observed to be two-layered and may contribute to the process of regurgitation of rough food and assist in mastication with the palatine plicae. Formation and patterns of the arterial network in the lamina propria are in a close relation with connective tissue elements. The subepithelial capillary network constitutes an advanced base for the ascending crus of the capillary loop and its pattern is affected by the properties of the connective tissue papillae and the diverging fashion of the capillary loops. Capillary loops of the transverse palatine plica are arranged parallel to the sagittal axis and at right angles to the top line of each plica. Features of the capillary loops are characteristics in the top, the anterior and posterior slopes of the plica, respectively. High connective tissue papillae in both the anterior slope and plical top may be of a resistant form for mollifying exhaustion, affected by the periodicity and mastication function. Although it is difficult to elucidate the lamination of the palatine mucosa in histological slides, it was resolved by examination on its vascular architectures.