bluuebunny/crossref_metadata_2025 huggingface dataset:
iTRAQ analysis of colorectal cancer cell lines suggests Drebrin (DBN1) is overexpressed during liver metastasis
Authors: Lin Qifeng , Tan Hwee Tong , Lim Teck Kwang , Khoo Avery , Lim Kiat Hon , Chung Maxey C. M.
Published: March 2014

Colorectal cancer is currently the third in cancer incidence worldwide and the fourth most common cause of cancer deaths. Mortality in colorectal cancer is often ascribed to liver metastasis. In an effort to elucidate the proteins involved in colorectal cancer liver metastasis, we compared the proteome profiles of the human colon adenocarcinoma cell line HCT‐116 with its metastatic derivative E1, using the iTRAQ labelling technology, coupled to 2D‐LC and MALDI‐TOF/TOF MS. A total of 547 proteins were identified, of which 31 of them were differentially expressed in the E1 cell line. Among these proteins, the differential expressions of translationally controlled tumour protein 1, A‐kinase anchor protein 12 and Drebrin (DBN1) were validated using Western blot. In particular, DBN1, a protein not previously known to be involved in colorectal cancer metastasis, was found to be overexpressed in E1 as compared to HCT‐116 cells. The overexpression of DBN1 was further validated using immunohistochemistry on colorectal cancer tissue sections with matched lymph node and liver metastasis tissues. DBN1 is currently believed to be involved in actin cytoskeleton reorganisation and suppresses actin filament cross‐linking and bundling. Since actin reorganisation is an important process for tumour cell migration and invasion, DBN1 may have an important role during colorectal cancer metastasis.
Improvement of light extraction efficiency of 350‐nm emission UV light‐emitting diodes
Authors: Nakashima Tsubasa , Takeda Kenichiro , Iwaya Motoaki , Takeuchi Tetsuya , Kamiyama Satoshi , Akasaki Isamu , Amano Hiroshi
Published: March 2014

In this study, we have aimed to improve the light extraction efficiency by using p‐ and n‐ high‐reflectivity indium tin oxide (ITO)/Al electrodes with a reflectivity of ∼77% at 350 nm, laser lift‐off (LLO) method, and silicone sealing. By a combination of these three methods, the light output power and operating voltage of UV LEDs were improved to 23.8 mW and 6.6 V at 100 mA. Furthermore, the external quantum efficiency and light extraction efficiency were improved to 6.6 and 25.3% at 100 mA. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Progressing management of non‐obstructive azoospermia in the era of microdissection testicular sperm extraction
Authors: Kanto Satoru , Yamasaki Kazumitsu , Iwamoto Teruaki
Published: March 2014

Previously, it was absolutely impossible for azoospermic men to reproduce except in some obstructive azoospermic cases for whom reconstruction of the seminal pathway was successful. However, nowadays, intracytoplasmic sperm injection and microdissection testicular sperm extraction have brought about chances of biological paternity in some non‐obstructive azoospermic men. It is almost 15 years since the first trials of testicular sperm retrieval using surgical microscopy for non‐obstructive azoospermia were reported. In this manuscript, the progress and outcomes of these novel techniques since then are reviewed, the controversial points are discussed and the latest research to achieve pregnancies in tough non‐obstructive azoospermic couples are introduced. Not only the bright side of the renovations, but the underlying concerns are also discussed.
Thomas Jefferson Versus the Historians: Christianity, Atheistic Morality, and the Afterlife
Authors: Scherr Arthur
Published: March 2014

For many years, the Religious Right has argued that Thomas Jefferson's “wall of separation” metaphor, expounded in his address to the Danbury Baptist Association in 1802, did not reflect his true views on cooperation between Church and State; and that he was actually a devout Christian who embraced a symbiotic relationship between them. Recent scholarship, concurring with these views, contends that Jefferson's thoughts and actions, both in political office and as a private individual, reflected his desire for government participation in religious ceremonies and his sincere dedication to the Christian faith. This article refutes such arguments. It compares Jefferson's ideas with John Adams's more orthodox opinions, particularly in their attitudes toward the connection between atheism and personal morality. The article notes that Jefferson, while endorsing Jesus' ethical teachings, also embraced philosophical materialism. He probably did not believe in an afterlife. Jefferson's most thoroughgoing rejection of organized Christianity occurred in old age, when his fading hopes for religious reform latched onto Unitarianism.
Self-assembly of octachloroperylene diimide into 1D rods and 2D plates by manipulating the growth kinetics for waveguide applications
Authors: Liu Huiying , Cao Xinqiang , Wu Yishi , Liao Qing , Jiménez Ángel J. , Würthner Frank , Fu Hongbing
Published: March 2014

This communication describes the facile synthesis of Cl8-PTCDI 1D rods and 2D plates by controlling the growth kinetics, as well as their shape dependent optical waveguides.
On the origin of the very strong two-photon activity of squaraine dyes – a standard/damped response theory study
Authors: Alam Md. Mehboob , Chattopadhyaya Mausumi , Chakrabarti Swapan , Rizzo Antonio
Published: March 2014

In the present work, we report the mechanism of a very large increase in the two-photon (TP) activity of squaraine based molecules upon changing the substituents.
Fluid inclusion measurements by laser ablation sector-field ICP-MS
Authors: Wälle M. , Heinrich C. A.
Published: March 2014

The performance of a sector field ICP-MS in comparison with a quadrupole ICP-MS for fluid inclusion analysis has been evaluated.
Prediction of the efficiency of diastereoisomer separation on the basis of the behaviour of enantiomeric mixtures
Authors: Pálovics Emese , Szeleczky Zsolt , Fődi Balázs , Faigl Ferenc , Fogassy Elemér
Published: March 2014

The composition of a crystalline diastereoisomer (eeDIA) is determined either by the eutectic composition of the racemic compound (eeEuRac) or that of resolving agent (eeEuRes) and the higher ee value has the more dominant effect.
Highly conductive and uniform graphene oxide modified PEDOT:PSS electrodes for ITO-Free organic light emitting diodes
Authors: Wu Xinkai , Liu Jun , Wu Dongqing , Zhao Yanru , Shi Xindong , Wang Jing , Huang Saijun , He Gufeng
Published: March 2014

We have successfully obtained a highly transparent and conductive film by doping poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) with graphene oxide (GO) and sodium dodecyl benzene sulfonate (SDBS).
Superior magnetic, dielectric, and magnetodielectric effects in graphene/ZnCo2O4 nanocomposites
Authors: Baskey Moni , Maiti Ramaprasad , Kumar Saha Shyamal , Chakravorty Dipankar
Published: March 2014

Although intensive research on spinel nanostructures has already been carried out, ZnCo2O4 is comparatively a less studied material because of its poor magnetic and dielectric properties. To focus ZnCo2O4 as a promising material with superior magnetic and dielectric properties in the present work, 2-dimentional nanosheets of ZnCo2O4 were synthesized using the large graphene surface as a template. Strong ferromagnetic behavior with asymmetries in coercivities is observed at room temperature. This was ascribed to the presence of Co2+ and Co3+ ions in ZnCo2O4 which gave rise to uncompensated spins due to a superexchange interaction. The nanocomposites containing large interfaces between graphene and ZnCo2O4 nanosheets exhibited unusual dielectric response due to trap states and superior magnetodielectric effect with an 18% change in dielectric permittivity for an applied magnetic field of 2.0 T as a result of combined effect between the Maxwell-Wagner polarization at the interface and a negative magnetoresistance of the ZnCo2O4 phase.
Magnetic energy harvesting properties of piezofiber bimorph/NdFeB composites
Authors: Han Jinchi , Hu Jun , Wang Shan X. , He Jinliang
Published: March 2014

The magnetic energy harvesting properties of piezoelectric bimorph/magnet composite are studied in this Letter. The devices are fabricated with NdFeB magnets and piezofiber (d33 mode), whose magnetoelectric (ME) coefficient reaches 526 V/cm·Oe (RMS) at the resonant frequency (27.3 Hz), and the maximum power density of which is 38.8 mW/cm3 at 9.78 Oe. Factors influencing the magnetoelectric property of the piezoelectric/magnet composite are discussed, which might guide further enhancement of its energy harvesting ability. This particular ME composite possesses far better energy harvesting abilities than magnetostrictive/piezoelectric composites, able to scavenge energy from power-frequency magnetic fields to support wireless sensor network.
A field experiment on grass fire effects on wooden constructions and peat layer ignition
Authors: Grishin A. M. , Filkov A. I. , Loboda E. L. , Reyno V. V. , Kozlov A. V. , Kuznetsov V. T. , Kasymov D. P. , Andreyuk S. M. , Ivanov A. I. , Stolyarchuk N. D.
Published: March 2014

This paper investigates the cause of ignition of wooden shields during surface fire fronts. For this purpose an experiment was conducted in which a zone 50m in length and 10m in width was chosen as the experimental site. Wooden shields (made of spruce boards) and samples of high-moor and valley peat were placed in this zone. In the experiment it was ascertained that to ensure safety during the surface fire in absence of firebrands and embers it was necessary to clear a perimeter around the zone not less than 5m in width, and remove cleared fuels. To reduce the risk of fence ignition, it was necessary to make the fences permeable. It was found that grass fires turn into peat fires if there is a conductor of combustion above the layer of peat.
Mapping the daily progression of large wildland fires using MODIS active fire data
Authors: Veraverbeke Sander , Sedano Fernando , Hook Simon J. , Randerson James T. , Jin Yufang , Rogers Brendan M.
Published: March 2014

High temporal resolution information on burnt area is needed to improve fire behaviour and emissions models. We used the Moderate Resolution Imaging Spectroradiometer (MODIS) thermal anomaly and active fire product (MO(Y)D14) as input to a kriging interpolation to derive continuous maps of the timing of burnt area for 16 large wildland fires. For each fire, parameters for the kriging model were defined using variogram analysis. The optimal number of observations used to estimate a pixel’s time of burning varied between four and six among the fires studied. The median standard error from kriging ranged between 0.80 and 3.56 days and the median standard error from geolocation uncertainty was between 0.34 and 2.72 days. For nine fires in the south-western US, the accuracy of the kriging model was assessed using high spatial resolution daily fire perimeter data available from the US Forest Service. For these nine fires, we also assessed the temporal reporting accuracy of the MODIS burnt area products (MCD45A1 and MCD64A1). Averaged over the nine fires, the kriging method correctly mapped 73% of the pixels within the accuracy of a single day, compared with 33% for MCD45A1 and 53% for MCD64A1. Systematic application of this algorithm to wildland fires in the future may lead to new information about vegetation, climate and topographic controls on fire behaviour.
Pericardial Effusion in Pulmonary Arterial Hypertension
Authors: Sahay Sandeep , Tonelli Adriano R.
Published: March 2014

Pulmonary arterial hypertension (PAH) is a serious condition that can lead to right heart failure and death. Pericardial effusion in PAH is associated with significant morbidity and mortality, and its pathogenesis is complex and poorly understood. There are few data on the prevalence of pericardial effusion in PAH, and more importantly, the management of pericardial effusion is controversial. Current literature abounds with case reports, case series, and retrospective studies that have limited value for assessing this association. Hence, we summarize the available evidence on this ominous association and identify areas for future research.
Reactive Oxygen Species Scavengers Improve Voltage‐Gated K+ Channel Function in Pulmonary Arteries of Newborn Pigs with Progressive Hypoxia‐Induced Pulmonary Hypertension
Authors: Fike Candice D. , Aschner Judy L. , Kaplowitz Mark R. , Zhang Yongmei , Madden Jane A.
Published: March 2014

Changes in voltage‐gated K+ (Kv) channel function contribute to the pathogenesis of pulmonary hypertension. Yet the mechanisms underlying Kv channel impairments in the pulmonary circulation remain unclear. We tested the hypothesis that reactive oxygen species (ROSs) contribute to the Kv channel dysfunction that develops in resistance‐level pulmonary arteries (PRAs) of piglets exposed to chronic in vivo hypoxia. Piglets were raised in either room air (control) or hypoxia for 3 or 10 days. To evaluate Kv channel function, responses to the Kv channel antagonist 4‐aminopyridine (4‐AP) were measured in cannulated PRAs. To assess the influence of ROSs, PRAs were treated with the ROS‐removing agent M40403 (which dismutates superoxide to hydrogen peroxide), plus polyethylene glycol catalase (which converts hydrogen peroxide to water). Responses to 4‐AP were diminished in PRAs from both groups of hypoxic piglets. ROS‐removing agents had no impact on 4‐AP responses in PRAs from piglets exposed to 3 days of hypoxia but significantly increased the response to 4‐AP in PRAs from piglets exposed to 10 days of hypoxia. Kv channel function is impaired in PRAs of piglets exposed to 3 or 10 days of in vivo hypoxia. ROSs contribute to Kv channel dysfunction in PRAs from piglets exposed to hypoxia for 10 days but are not involved with the Kv channel dysfunction that develops within 3 days of exposure to hypoxia. Therapies to remove ROSs might improve Kv channel function and thereby ameliorate the progression, but not the onset, of pulmonary hypertension in chronically hypoxic newborn piglets.
Statistical Study of Solar X-Ray Jets Observed with the Yohkoh Soft X-Ray Telescope
Authors: Shimojo Masumi , Hashimoto Shizuyo , Shibata Kazunari , Hirayama Tadashi , Hudson Hugh S. , Acton Loren W.
Published: March 2014

We have found 100 X-ray jets in the database of full Sun images taken with the Soft X-ray Telescope (SXT) aboard Yohkoh during the period from 1991 November through 1992 April. A statistical study for these jets results in the following characteristics: 1) Most are associated with small flares (microflaressubflares) at their footpoints. 2) The lengths lie in the range of a few × 104−4 × 105 km. 3) The widths are 5 × 103–105 km. 4) The apparent velocities are 10–1000 km s−1 with an average velocity of about 200 km s−1 . 5) The lifetime of the jet extends to ˜ 10 hours and the distribution of the observed lifetime is a power law with an index of ˜ 1.2. 6) 76% of the jets show constant or converging shapes; the width of the jet is constant or decreases with distance from the foot point. The converging type tends to be generated with an energetic foot point event and the constant type by a wide energy range of the footpoint event. 7) Many jets (˜ 68%) appear in or near to active regions (AR). Among the jets ejected from bright-point like features in ARs, most (˜ 86%) are observed to the west of the active region. 8) 27% of the jets show a gap ( > 104 km) between the exact footpoint of the jet and the brightest part of the associated flare. 9) The X-ray intensity distribution along an X-ray jet often shows an exponential decrease with distance from the footpoint. This exponential intensity distribution holds from the early phase to the decay phase.
Disk Instability-Induced Hard-Soft Transition in Soft X-Ray Transients
Authors: Mineshige Shin
Published: March 2014

Soft X-ray transients that are black-hole candidates (BHCs) exhibit hysteretic spectral transitions during outbursts; hard X-ray peaks generally precede soft X-ray peaks. To account for such behavior we propose a new model, in which the disk behavior is distinct across a critical radius. The outer portions suffer a thermal limit-cycle instability owing to partial ionization of hydrogen and helium, thereby modulating mass flow into the inner portions. In order to produce weak X-rays during the quiescence, however, the instability should be suppressed in the inner portions, probably due to small optical depths. Instead, the inner portions undergo forced bimodal transitions between the optically thick and thin branches in response to variable mass input from the outer portions. The inner part is on the optically thin, advection-dominated branch in the quiescence and rise phases, thus producing hard power-law radiation, while it is on the optically thick branch in the early decay phase, predominantly emitting soft radiation. Our model can basically account for the observations of black-hole transients.
Non-Local Effects of Turbulence on the Excitation of Trapped Oscillations in Dwarf-Nova Accretion Disks
Authors: Yamasaki Tatsuya , Kato Shoji
Published: March 2014

In a previous paper we showed, in order to suggest one possible mechanism of quasi-periodic oscillations (QPOs), that some axially symmetric radial oscillations can be trapped and excited in dwarf-nova accretion disks. This study was done by using a diffusion-type turbulent stress tensor. The adoption of a diffusiontype stress tensor is, however, not suitable, since the relaxation time of turbulence in Keplerian disks is comparable with the timescale of the oscillations, and the delay of the time response of the turbulence to the oscillations has non-negligible effects on the excitation of oscillations. In this paper we reexamine the excitation of trapped oscillations on dwarf-nova disks by taking the effects of the above-mentioned time delay of the stress tensor into account. The results show that although the growth rate of trapped oscillations decreases by a factor of 2-3, the oscillations are still excited, except for cases when the temperature dependence of the opacity is weak and the viscosity is small.
Quasar Lensing Caused by Clusters of Galaxies in Various Cosmological Models
Authors: Tomita Kenji
Published: March 2014

About 33% of the observed lensed quasars have separation angles larger than 3″. To theoretically reproduce this observational fact, we investigate the statistics of quasar lensing due to clusters of galaxies, in various cosmological models including a super-horizon-scale inhomogeneous model. By calculating the expected number of lensed quasars and comparing it with the observed number in the Hubble Space Telescope snapshot survey, it is found that a reasonable number of lensed quasars with such large separation angles can be obtained in the cosmological-constant-dominant low-density models and the super-horizonscale inhomogeneous models with a low-density inner region. From the standpoint of lens statistics due to clusters of galaxies, it is concluded that these cosmological models are better, in contrast to the previous results in the galactic lens models.
Evolution of the Intergalactic Medium and UV Background Radiation
Authors: Okoshi Katsuya , Ikeuchi Satoru
Published: March 2014

The absence of an HI Gunn-Peterson trough extending to the blue side of the Lyman α emission in the spectra of high-redshift quasars has placed a severe limit on the density of neutral hydrogen in the intergalactic medium. In addition, a probable detection of a HeII Gunn-Peterson trough has been reported, though it is controversial. On the other hand, numerous and narrow absorption lines in quasar spectra have been interpreted as the so-called Lyman α forest. They would play an important role in relation to the evolution of the UV background radiation at high redshifts. We calculate the evolution of the UV background radiation, and explore the ionization states of intergalactic gas and clouds while trying to solve any mutual relations among them consistently. We examine two such models for the Lyman α clouds as pressure-confined and for the clouds confined by cold dark matter, the minihalos. For the former, the evolution is not consistent with other observational constraints, because these clouds with low HI column densities evolve too rapidly to be missed in detection at low redshifts, z ≲ 2, contrary to the HST observations that more numerous Lyman α absorption lines exist than predicted by extrapolation from high redshift. Otherwise, the minihalos cannot reproduce the evolution of the Lyα forest at high redshifts if assumed that the evolution of the UV background is proportional to the number of QSOs. Consequently, we propose a two-component model: pressure-confined clouds at high redshifts and minihalos at low redshifts, while satisfying all of the observational constraints marginally within resonable parameters.
Evidence for a Pulsar Jet Producing a Hot Nebula in the Supernova Remnant MSH 15—52
Authors: Tamura Keisuke , Kawai Nobuyuki , Yoshida Atsumasa , Brinkmann Wolfgang
Published: March 2014

We have discovered direct evidence for a pulsar jet from the young X-ray and radio pulsar PSR 1509–58 in the supernova remnant MSH 15–52 with the X-ray astronomy satellite ASCA. With its high-energy resolution combined with its imaging capability over a wide energy band, ASCA has studied the two morphologically and spectroscopically different components in this supernova remnant: a non-thermal nebula powered by the pulsar with a jet-like structure, and a hot thermal plasma cloud located at the end of the “jet”. We propose that the jet is a stream of relativistic electrons generated by the pulsar, and that the thermal nebula is created by the collision of the jet with interstellar matter. This scenario can explain the peculiar X-ray morphology and the energy budget of MSH 15–52 consistently.
Coma Cluster: Hot and Cool Mixture
Authors: Ishizaka Chiharu , Mineshige Shin
Published: March 2014

ASCA has revealed a rather complex temperature structure in the intracluster medium (ICM) around the Coma cluster. Significantly, hot parts (with kT ≥ 10 keV) are located far (∼ 1 Mpc) distant from both the center of the Coma cluster and the galaxy group NGC 4839. There also exist relatively cool regions (with kT ≲ 5 keV). Using N-body + Hydrodynamic simulations, we have demonstrated that such an observed temperature distribution is naturally accounted for if the subgroup NGC 4839 passed through the center of the Coma cluster about 1 Gyr ago, which was first proposed by Burns et al. When the subcluster passed through the Coma cluster, the ICM in the subcluster was compressed due to the ram pressure by the ICM in the Coma, and there formed a bow shock with an arc shape just between the two centers. The ICM has thus been heated there, emitting hard radiation. A part of the ICM is reflected by the shock front, and flows backward (with respect to the direction of the subcluster motion) around the Coma cluster center, being cooled due to an adiabatic expansion. After detouring the center, cooled gas collides with each other at the opposite side of the Coma cluster (to the place of the subcluster), producing another hot region. These simulated features are in good agreement with what ASCA found. Further, we present rather unique features in the temperature profiles that can be caused by a merger (or an encounter) with a subgroup of galaxies.
Evolution of the UV Background: The Effect of Radiative Cooling Photons from Collapsing Objects
Authors: Inagaki Yuichiro , Sasaki Shin
Published: March 2014

We discuss the evolutions of the intensity and spectrum of the UV background radiation (UVB) in flat and open cold dark-matter universes. We consider two kinds of UV sources: one is QSOs, the other is collapsing objects, which liberate their binding energy radiatively. In the latter sources, we include the line emission corresponding to collisional excitation cooling of He II as well as free-free emission. We find that UV photons emitted from collapsing objects contribute to UVB as much as those from QSOs, and that the UVB spectrum becomes softer than that in the case in which only QSOs are taken into account. We also calculate the Gunn-Peterson optical depths assuming the ionization equilibrium, and compare them with observations.
Structure of an X-Ray Cluster of Galaxies with a Central Giant Elliptical Galaxy and Gravitational Lensing
Authors: Makino Nobuyoshi
Published: March 2014

We consider a mass distribution in the cluster A2218 which is consistent with the observed giant arcs and the X-ray surface brightness. It is confirmed that the central giant elliptical galaxy plays an important role in the gravitational lens effect and the X-ray emitting gas distribution, and that the giant galaxy mainly contributes to the mass within the core radius of the cluster, but the cluster component outside of the core radius dominates in the total mass. For the X-ray surface brightness, it is shown that the observed data can be reproduced theoretically in a model having a gas distribution such that its temperature increases toward the center.
Collapse and Fragmentation of Cylindrical Magnetized Clouds: Simulation with Nested Grid Scheme
Authors: Tomisaka Kohji
Published: March 2014

The fragmentation process in a cylindrical magnetized cloud has been studied using the nested grid method. The nested grid scheme uses 15 levels of grids with increasing spatial resolution, which enabled us to trace the evolution from molecular cloud densities ∼ 100 cm−3 to that of protostellar disks, ∼ 1010 cm−3 or higher. Fluctuations with small amplitude grow due to a gravitational instability. A disk is formed whose symmetric plane is perpendicular to magnetic field lines which run in the direction parallel to the major axis of the cloud. Matter accretes onto the disk, mainly flowing along the magnetic fields. This increases the column density. The radial inflow velocity is slower than the flow perpendicular to the disk, which is driven by an increase of the gravity. The contraction continues indefinitely for an isothermal equation of state and while the magnetic fields are perfectly coupled to matter. Both conditions are realized in the density range of ρ ≲ 1010 cm−3. The structure of the contracting disk reaches that of a singular solution as the density and column density obey ρ(r) ∝ r−2 and σ(r) ∝ r−1, respectively. The magnetic field strength in the mid-plane is proportional to ρ(r)1/2 and the field at the center (Bc) evolves proportionally to the square root of the gas density (∝ ρc1/2). It is shown that isothermal clouds experience a “run-away„ collapse. The evolution, including a hardening of the equation of state due to radiation trapping, is also discussed.
Non-LTE Abundance Analyses of Nitrogen and Sulfur in Chemically Peculiar Stars of the Upper Main Sequence
Authors: Takada-Hidai Masahide , Takeda Yoichi
Published: March 2014

The LTE and non-LTE abundances of nitrogen (N) and sulfur (S) in chemically peculiar stars of the upper main sequence were derived from the NI and SI lines observed in a near-infrared spectral region. The sample consisted of 11 stars: three HgMn stars, two Am stars, three magnetic Ap (SrCrEu) stars, two weak-lined stars, and one normal star. The following results were obtained: (1) the LTE abundances of N suffer a large non-LTE effect with correction factors of up to −0.6 dex, while those of S suffer a minor non-LTE effect with correction factors of up to −0.2 dex; (2) the non-LTE abundances of N are systematically below solar value among the sample stars. Although the deficiencies of N are mild in the normal and weak-lined stars, they are enhanced by a factor of up to 2 dex in HgMn stars. A star-to-star variation with a range of 1 dex or more in the N deficiency is shown in Am and SrCrEu stars; (3) the non-LTE abundances of S are solar or slightly overabundant among the sample stars, except for SrCrEu stars. S is systematically deficient relative to the Sun by a factor of ≳ 0.7 dex in SrCrEu stars.
Mid-Infrared Spectral Observations of Point Sources by IRTS
Authors: Yamamura Issei , Onaka Takashi , Tanabé Toshihiko , Roellig Thomas L. , Yuen Lunming
Published: March 2014

The mid-infrared spectrometer on board Infrared Telescope in Space has detected thousands of point-like sources in the spectral range of 4.5–11.7 μm. Extraction of point sources from the survey data has been carried out for the observing period after the spin-flip, where accurate pointing information is presently available, and 129 point sources have been extracted with signal-to-noise ratios greater than 3 throughout the MIRS spectral range. A two-color diagram of these objects, derived from bands of 5 μm, 8 μm, and 10 μm of the sources, is presented. The sources can be classified into five groups on the diagram: visible late-type stars, stars with dust envelopes, stars with silicate emission, objects with the unidentified infrared (UIR) emission bands, and very peculiar red objects. With the help of the 5 μm and 8 μm colors, objects with the UIR bands can clearly be distinguished from objects without those features. The characteristics of the sources in each group are discussed based on the spectra.
X-Ray/Soft Gamma-Ray Observation of Centaurus A and Its Implication on the Emission Mechanism
Authors: Miyazaki Satoshi , Takahashi Tadayuki , Gunji Shuichi , Hirayama Masaharu , Kamae Tuneyoshi , Sekimoto Yutaro , Tamura Tadahisa , Tanaka Mitsuaki , Yamasaki Noriko Y. , Inoue Hajime , Kano Takako , Yamagami Takamasa , Nomachi Masaharu , Murakami Hiroyuki , Braga John , Neri J. Angelo
Published: March 2014

We have studied Cen A (NGC 5128) in the X-ray band (3–20 keV) and soft γ-ray band (40–600 keV) with the Large Area Counter (LAC) of the Ginga satellite (1989 March and 1990 February) and with a balloon-borne low background detector (Welcome-1, 1991 November), respectively. The observed continuous spectra show a power-law shape (Γ∼ 1.8) with relatively heavy absorption (NH ∼ 1.5 × 1023 H cm−2) at the low-energy end and a possible break at ∼ 180 keV. We analyzed the total spectra as the sum of the direct power-law flux from the central engine, the Compton-scattered flux from a cold cloud near to the engine, and the iron fluorescence-line flux. By assuming that the geometry around the central engine remained unchanged during the two-year period, we studied two possible cold cloud geometries by comparing Monte-Carlo simulations with our observations: the first is the Compton-reflection model in which the cloud forms a slab covering 2π sr behind the central engine, the second is a case where the central source is totally surrounded by a cold cloud. We found that the latter geometry reproduces our data well; the observed power-law spectrum is then identified as direct flux from the central engine which undergoes a break at ∼ 180 keV.
Discovery of a New SU UMa Star, CI Ursae Majoris
Authors: Nogami Daisaku , Kato Taichi
Published: March 2014

We detected superhumps with a period of 0.0625 (±0.0007) d in CI UMa during a bright outburst in 1995 January. From this, CI UMa was first proven to be a SU UMa-type dwarf nova. We found the interval of the superoutburst to be about 140 d from historical records of the outburst. If this represents the cycle length of the superoutburst (supercycle), CI UMa has the third-shortest supercycle among usual SU UMa stars, except for ER UMa stars. We regard CI UMa as being an intermediate object between ER UMa stars and the usual SU UMa stars based on the short orbital period estimated from the superhump period and the short supercycle. It may be crucial to clarify whether the supercycle has changed by closely monitoring CI UMa in order to solve any problem concerning the evolutionary path of ER UMa stars.
Fluorescent Lines from the Nucleus of Centaurus A
Authors: Sugizaki Mutsumi , Inoue Hajime , Sonobe Takashi , Takahashi Tadayuki , Yamamoto Yasushi
Published: March 2014

The results of a Centaurus A (NGC 5128) observation with the X-ray satellite ASCA on 1993 August 14 are reported. We have resolved the X-ray emission of this source into those from the nucleus and extended components. The spectrum of the nucleus in the 0.5–10 keV energy range was analyzed. In the energy range above 3 keV, the spectrum of the nucleus can be represented by a heavily absorbed power-law with NH ≃ 1023) cm−2 and a Fe Kα line. The flux of the Fe line implies that it originates from reprocession in the dense matter (NH ≃ 1023) cm−2) which completely surrounds the central X-ray source. In the energy range below 3 keV, the spectrum shows an excess over the power-law spectrum extrapolated from the higher energy range above 3 keV. In the soft excess component, three emission lines have been identified. The center energies of these lines correspond to those of the Kα lines of neutral Mg, Si, and S. The equivalent widths of these lines and the soft excess can be explained by fluorescence and scattering in relatively cold and thin (NH ≃ 1023) cm−2) matter illuminated by the central X-ray source. The complex configuration of the matter surrounding the central X-ray source is required to explain the flux of the Fe line and the soft excess component at the same time.
Disk Instability Model for the AM Canum Venaticorum Stars
Authors: Tsugawa Motohiko , Osaki Yoji
Published: March 2014

We examine AM CVn stars, ultra-short-period variables thought to have helium disks, from the stand-point of the disk instability model. By calculating the vertical structure of the helium accretion disks, we have confirmed that the helium accretion disks are thermally unstable, since their thermal-equilibrium curves exhibit the characteristic S-shaped form. We apply these results to AM CVn stars. We have found that the observed large-amplitude photometric variations in AM CVn stars can be explained by the thermal-tidal instability model of helium accretion disks.
VRI Light Curves of SS 433: Photometry and Model
Authors: Fukue Jun , Nakashima Rika , Arimoto Jun'ichi , Awano Yumi , Honda Satoshi , Ishikawa Kaoru , Kato Taichi , Kawai Nobuyuki , Matsumoto Katsura , Okugami Masamitsu , Sakaguchi Toshiki , Tajima Yukiko , Tanabe Kazuhito , Tsuda Kazumi , Watanabe Yoichi , Yamada Yasushi , Yokoo Takeo
Published: March 2014

We present the results of VRI CCD photometric observations of SS 433 and VRI light-curve modelings for SS 433. Observations were carried out in the fall of 1995 using the 51-cm relfector at Osaka Kyoiku University. Three cycles of the binary phase were covered. The mean magnitudes and colors during the observational periods were V = 14.0, R = 11.1, I = 10.5; V – R = 2.88, V – I = 3.50, R – I = 0.62. On October 17 and 18 a strong flare was observed. Theoretical light curves were also calculated using a model in which SS 433 consists of a geometrically thick torus around a compact star and a companion star filling the Roche lobe. In the torus picture VRI light curves were first calculated; for appropriate parameters VRI model light curves well reproduce the observational profiles. In addition, the extinction was first derived from the magnitude difference between the obervation and the model; AV ∼ 6–7, AR ∼ 3–4, and AI ∼ 3. These values are in good agreement with those of a previous observation.
Discovery of a Possible Impact Spot on Jupiter Recorded in 1690
Authors: Tabe Isshi , Watanabe Jun-ichi , Jimbo Michiwo
Published: March 2014

Upon surveying old drawings stored in libraries we discovered a dark spot drawn by G. Cassini in 1690 December. The size and visibility of this spot were similar to those produced by the impacts of Comet D/Shoemaker-Levy 9 in 1994. During the 18 d observational period, this spot was stretched mainly in the east–west direction by a zonal wind. Considering this circumstantial evidence together with a result of simple simulation of the time variation, we conclude that this spot was possibly produced by the impact of a single astronomical object around 1690 December 5.
Search for an X-Ray Counterpart to a Gamma-Ray Burst GRB 940217 with ASCA
Authors: Tokanai Fuyuki , Yoshida Atsumasa , Otani Chiko , Kawai Nobuyuki , Shibata Ryo , Murakami Toshio , Ueda Yoshihiro , Hurley Kevin
Published: March 2014

We report on the result of a search for an X-ray counterpart to the peculiar gamma-ray burst of 1994 February 17 (GRB 940217) detected with the ASCA satellite. This was one of the strongest bursts detected by BATSE onboard CGRO. Furthermore, it had the longest duration (90 min), and the hardest gamma-ray emission (∼ 18 GeV) of all GRBs observed so far. Three pointed observations with ASCA were performed to cover the error region determined by the EGRET (95% confidence level), COMPTEL (3σ confidence level), and the Interplanetary Network (IPN) localization. We detected one X-ray source (2–10 keV flux: 3.7 × 10−13 erg s−1 cm−2) within the error region. Using the APM system at the Royal Greenwich Observatory, we found two optical sources within 1′ of this source. One of the optical sources has a B — R color consistent with an AGN. The implied optical-to-X ray flux ratio is also reasonable for an AGN. If the X-ray source is an AGN with a luminosity of 1045) erg s−1) (4.7 Gpc; z = 1) and is the source of the burst, a lower limit on the relativistic bulk Lorentz beaming factor, ≿50, can be derived from the energy spectra and fine-time structure observed by COMPTEL.
Two-Arm Spiral Structure of Molecular Gas in the Flocculent Galaxy NGC 5055
Authors: Kuno Nario , Tosaki Tomoka , Nakai Naomasa , Nishiyama Kohta
Published: March 2014

We present the results of CO observations of the flocculent spiral NGC 5055 with the Nobeyama 45-m telescope. A long and symmetric two-arm spiral structure was found in the galaxy. Since the molecular arms are coincident with those of old stars seen in the K′-band, they are caused by a stellar density wave. The molecular spiral arms can be fitted with a logarithmic spiral with a pitch angle of 19°, which is comparable to that measured in M51. The arm-to-interarm ratio is 2–3 (R = 80″–160″) and increases with the galactocentric radius. Since bright HII regions also distribute along the molecular gas, massive star formation occurs in the arms. These results indicate that the flocculent spiral structure of NGC 5055 can not be explained solely by stochastic star formation.
Line Spectrum from Advection-Dominated Accretion Disks
Authors: Fukue Jun , Ohna Etsuko
Published: March 2014

The emission-line profiles from advection-dominated accretion disks were calculated for a wide variety of parameters. As a model of advection-dominated disks, we adopted a self-similar solution by Narayan and Yi (1994, AAA 61.064.083) and a beta disk driven by radiation drag by Fukue and Umemura (1995, AAA 64.064.034). The emissivity assumed was a power of the radius. The parameters are then the size of the emitting regions, the power index of the emissivity, and the inclination angle, except for a few parameters inherent in each model. The line profiles in advection-dominated cases, like those from a Keplerian disk, are generally double peaked, partly due to the rotational motion and partly due to the radial infall motion. In a Keplerian disk and a self-similar disk the separation of peaks depends on the size of the emitting regions, whereas does not depend on the size so much in the beta disk. One of the strategies to distinguish these models is to observe the separation for the different species, which originate in different regions on the disk. In addition, the separation for advection-dominated accretion disks is systematically small, since the rotational velocity is generally smaller than the Keplerian velocity. In profile variations during an eclipse a blue peak disappears at first and a red peak follows in the Keplarian disks, while both peaks change simultaneously in avection-dominated accretion disks. This can be another strategy to discriminate models.
A High-Temperature Component in Coronal Holes as Confirmed by a Partial-Eclipse Observation
Authors: Hara Hirohisa
Published: March 2014

We confirmed X-ray signals in coronal holes based upon a Yohkoh soft X-ray observation of a partial eclipse on 1993 November 13. The observed X-ray signals cannot be explained by those coming from one-million-degree plasmas alone, which were observed with the Skylab UV and EUV instruments. This suggests that higher-temperature plasmas are necessary to explain the present observation.
Self-Similar Viscous Collapse of a Self-Gravitating, Polytropic Gas Disk
Authors: Mineshige Shin , Nakayama Kunji , Umemura Masayuki
Published: March 2014

Self-similar solutions for the time evolution of polytropic, self-gravitating viscous disks is found on the condition that the kinematic viscosity is v ∝ rl and the gas pressure is P ∝ ρΓ, where l and Γ are free parameters, r is radius, and ρ is density. This solution describes a self-similar collapse of a rotating gas disk via self-gravity and viscosity. For Γ < Γc = (3 + 2l)/(3 + l) global accretion solutions exist, provided that 0 < l ≤ 1. Owing to the boundary condition of no radial velocity at the origin, mass is accumulated near to the center, giving rise to a strong central concentration; the surface density varies as Σ ∝ r−1−⅔l. In the outer portions, in contrast, the surface density more slowly decreases outward as Σ ∝ r−Γ/(2-Γ). For Γ > Γc, conversely, no global accretion solution is found.
The Short-Period Cepheid SU Cassiopeiae: Spectroscopic Diagnosis of its Rotation and Atmospheric Turbulence
Authors: Takeda Yoichi , Kawanomoto Satoshi , Ando Hiroyasu
Published: March 2014

A detailed non-LTE profile analysis of OI 7771–5 and KI 7699 based on the classical line-broadening model (i.e., rigid rotation, microturbulence, and radial-tangential macroturbulence) was carried out for the short-period Cepheid SU Cas at the phase of near-maximum radius, in order to establish its rotational velocity by separating the effect of atmospheric turbulence, which was motivated by the suspicion that its appreciably large radius, empirically derived by using the radial-velocity information (e.g., Wesselink method), might be nothing but due to an apparent rotational effect, shifting the position of the line-peak significantly. It turned out, however, that the best-fit was accomplished at vesin i ≃ 0 km s−1 for both cases of the line-profiles. This evidently indicates that the rotation is practically of negligible importance, and can not be the key to the “radius problem” of SU Cas, for which some other different explanation must be invoked.
Spectroscopic Study of C, N, O, and S Abundances in a Field Horizontal-Branch Star HD 161817
Authors: Takeda Yoichi , Sadakane Kozo
Published: March 2014

A detailed non-LTE analysis of neutral C, N, O, and S lines was performed based on a set of CCD spectra in the red and near-IR wavelength regions for a field Pop II horizontal-branch star HD 161817 (along with 20 CVn included for a comparison), in order to establish the photospheric abundances of these elements. It turned out that [O/Fe] and [S/Fe] show a mild excess, amounting to 0.4–0.5 dex, which agrees quantitatively well with that of typical halo dwarfs corresponding to [Fe/H] ∼ –1.5 (the metallicity of HD 161817), suggesting that the original composition is retained unaltered for oxygen and sulfur (α-elements). Meanwhile, the resulting abundances of carbon and nitrogen ([C/Fe] ∼ −0.2 and [N/Fe] ∼ +0.5) indicate a mixing of CN-cycle products, when compared with [C/Fe] =≃ [N/Fe] ≃ 0 (a typical value occasionally quoted for dwarfs in the halo). It was also found that the microturbulent velocity tends to increase with height in the atmosphere of HD 161817, which may be the cause for the discrepancy between the value established from blue metallic lines (2–3 km s−1) and that from OI 7771–5 (4 km s−1).
Gas-to-Dust Ratio of Two Comets: Implication for Inhomogeneity of Cometary Nuclei?
Authors: Kawakita Hideyo , Furusho Reiko , Fujii Mitsugu , Watanabe Jun-Ichi
Published: March 2014

We performed spectroscopic observations of Comet Tabur (C/1996Q1) from 1996 September 14 to October 16, on 9 nights. The gas-to-dust ratio was determined for C/Tabur, and compared with that of Comet Liller (C/1988A1), whose orbital elements are quite similar to those of C/Tabur. The gas-to-dust mass ratio obtained for C/Tabur is one order larger than C/Liller. Because this similarity of the orbits indicates a splitting of these comets in the past, the obtained difference in the gas-to-dust mass ratio should be due to an inhomogeneity of the cometary nucleus.
X-Ray Study of the Distant QSO PKS 0237–233 with ASCA and ROSAT
Authors: Yamasaki Noriko Y. , Miyazaki Hiroyuki , Ohashi Takaya , Wilkes Belinda J.
Published: March 2014

The X-ray spectrum of the distant QSO PKS 0237–233 (z = 2.223) has been studied with ASCA and ROSAT. The spectrum in the energy range 0.1 keV to 8 keV in the observer's frame is well fitted by a power-law model with a photon index of 1.54 ± 0.06 absorbed by the galactic interstellar matter. The lack of excess absorption confirms that such absorption is not a universal property of the high-redshift GHz-peaked spectrum (GPS) sources. From a comparison of the Lyman alpha and the metal absorption lines in the optical and UV bands, small amount of X-ray absorption constrains the ionization state of the metal line system at z = 1.65 as [HI/H] > 2.5 × 10−4 and [CIV/C] > 0.11 if the metal line systems have a metal abundance of 0.1Z⊙.
A Systematic Search for Galaxies behind the Milky Way at Sagittarius
Authors: Roman Adel T. , Nakanishi Kouichiro , Saitō Mamoru
Published: March 2014

This is the second paper concerning our systematic search for galaxies behind the Milky Way at the galactic center region. The searched area was about 260 square degrees between l = ≃ −7° and 16° and b ≃ −19° and −1°, and a total of 7154 galaxies and galaxy candidates with sizes of 0′.1 or greater were identified. Among these detected objects, 52 are given in the ESO galaxy catalog and another 55 are associated with IRAS point sources containing 13 IRAS galaxies with known redshifts. We made a catalog of the detected objects, in which the position in (α, δ) and (l, b), the size, and the features of the image, and the multiplicity are given for each object. The surface number densities of the detected objects mainly depend on the galactic latitude as well as on the distribution of nearby dark clouds. Although the sky distribution and size distribution of the detected objects show the presence of a cluster candidate of galaxies at a distance further than 100 Mpc, there is no evidence of any nearby clusters.
Discovery of a Compact X-Ray Source inside the Cygnus Loop
Authors: Miyata Emi , Tsunemi Hiroshi , Torii Ken’ichi , Hashimotodani Kiyoshi , Tsuru Takeshi , Koyama Katsuji , Ayani Kazuya , Ohta Kouji , Yoshida Michitoshi
Published: March 2014

We detected a compact X-ray source inside the Cygnus Loop during observations of the whole Cygnus Loop with the ASCA GIS. The source intensity is 0.11 c s−1 for GIS and 0.15 c s−1 for SIS, which is the strongest in the ASCA band. The X-ray spectra are well fitted by a power-law spectrum having a photon index of −2.1 ±0.1 with a neutral H column of (3.1±0.6)×1021 cm−2 . Taking into account the interstellar absorption feature, this source is X-ray bright, mainly above 1 keV, suggesting either an AGN or a rotating neutron star. So far, we have not detected any intensity variation or coherent pulsation, mainly due to the limited observation time. There are several bright optical stellar objects within the error region of the X-ray image. We carried out optical spectroscopy for the brightest source (V=+12.6), and found it to be a G star. Follow-up deep observations in both optical and X-ray wavelengths are strongly required.