bluuebunny/crossref_metadata_2025 huggingface dataset:
Hypoxia Preconditioning Increases Survival and Decreases Expression of Toll‐Like Receptor 4 in Pulmonary Artery Endothelial Cells Exposed to Lipopolysaccharide
Authors: Ali Irshad , Nanchal Rahul , Husnain Fouad , Audi Said , Konduri G. Ganesh , Densmore John C. , Medhora Meetha , Jacobs Elizabeth R.
Published: March 2014

Pulmonary or systemic infections and hypoxemic respiratory failure are among the leading causes of admission to intensive care units, and these conditions frequently exist in sequence or in tandem. Inflammatory responses to infections are reproduced by lipopolysaccharide (LPS) engaging Toll‐like receptor 4 (TLR4). Apoptosis is a hallmark of lung injury in sepsis. This study was conducted to determine whether preexposure to LPS or hypoxia modulated the survival of pulmonary artery endothelial cells (PAECs). We also investigated the role TLR4 receptor expression plays in apoptosis due to these conditions. Bovine PAECs were cultured in hypoxic or normoxic environments and treated with LPS. TLR4 antagonist TAK‐242 was used to probe the role played by TLR4 receptors in cell survival. Cell apoptosis and survival were measured by caspase 3 activity and 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) incorporation. TLR4 expression and tumor necrosis factor α (TNF‐α) production were also determined. LPS increased caspase 3 activity in a TAK‐242‐sensitive manner and decreased MTT incorporation. Apoptosis was decreased in PAECs preconditioned with hypoxia prior to LPS exposure. LPS increased TNF‐α production, and hypoxic preconditioning blunted it. Hypoxic preconditioning reduced LPS‐induced TLR4 messenger RNA and TLR4 protein. TAK‐242 decreased to baseline the LPS‐stimulated expression of TLR4 messenger RNA regardless of environmental conditions. In contrast, LPS followed by hypoxia substantially increased apoptosis and cell death. In conclusion, protection from LPS‐stimulated PAEC apoptosis by hypoxic preconditioning is attributable in part to reduction in TLR4 expression. If these signaling pathways apply to septic patients, they may account for differing sensitivities of individuals to acute lung injury depending on oxygen tensions in PAECs in vivo.
Intersectin‐1s: An Important Regulator of Cellular and Molecular Pathways in Lung Injury
Authors: Predescu Dan N. , Bardita Cristina , Tandon Rajive , Predescu Sanda A.
Published: March 2014

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are severe syndromes resulting from the diffuse damage of the pulmonary parenchyma. ALI and ARDS are induced by a plethora of local or systemic insults, leading to the activation of multiple pathways responsible for injury, resolution, and repair or scarring of the lungs. Despite the large efforts aimed at exploring the roles of different pathways in humans and animal models and the great strides made in understanding the pathogenesis of ALI/ARDS, the only viable treatment options are still dependent on ventilator and cardiovascular support. Investigation of the pathophysiological mechanisms responsible for initiation and resolution or advancement toward lung scarring in ALI/ARDS animal models led to a better understanding of the disease's complexity and helped in elucidating the links between ALI and systemic multiorgan failure. Although animal models of ALI/ARDS have pointed out a variety of new ideas for study, there are still limited data regarding the initiating factors, the critical steps in the progression of the disease, and the central mechanisms dictating its resolution or progression to lung scarring. Recent studies link deficiency of intersectin‐1s (ITSN‐1s), a prosurvival protein of lung endothelial cells, to endothelial barrier dysfunction and pulmonary edema as well as to the repair/recovery from ALI. This review discusses the effects of ITSN‐1s deficiency on pulmonary endothelium and its significance in the pathology of ALI/ARDS.
From Short‐Term Benefits to Long‐Term Outcomes: The Evolution of Clinical Trials in Pulmonary Arterial Hypertension
Authors: Chakinala Murali M. , Barst Robyn
Published: March 2014

Over the past 2 decades, major advances in our understanding of pulmonary arterial hypertension (PAH) have led to the development of new targeted therapeutics and management strategies that have provided benefits to patients with this devastating disease. Despite such improvements, no therapies are curative, and PAH remains a progressive disease associated with high morbidity and suboptimal survival in many patients. Clinical research in PAH is currently at a crossroads. To move forward, not only are new therapies needed, but novel approaches to clinical trial design are also required. Trials should be designed to assess the longer‐term benefits of investigational therapies in what has become a chronic disease. Moreover, there is a need to consider moving away from short‐term trials that use markers such as the 6‐minute walk distance as a measure of exercise capacity as primary end points to longer‐term, event‐driven trials with composite end points made up of clinically relevant measures that better reflect the ultimate goals of reducing morbidity and mortality. A shift in trial design may also be useful in overcoming some of the muted results from recent pivotal phase III studies of combination therapy by allowing the potential of these regimens to be more comprehensively assessed.
Updating Clinical Endpoints in Pulmonary Arterial Hypertension: When Challenges are Welcome
Authors: Hassoun Paul M. , Nikkho Sylvia , Oudiz Ronald J.
Published: March 2014

We thank Ms. Deborah McCollister for her feedback on our recent article titled “Updating clinical endpoint definitions.” McCollister judiciously points out some of the challenges raised with the recent trend among investigators and pharmaceutical companies involved in pulmonary arterial hypertension (PAH) clinical trials to move away from the 6‐minute walk distance (6MWD) as a primary outcome in favor of a more composite endpoint, such as time to clinical worsening (TTCW), which includes elements of morbidity (such as hospitalization, clinical worsening, and need for additional therapy) and mortality.
Estimating optimal window size for analysis of low-coverage next-generation sequence data
Authors: Gusnanto Arief , Taylor Charles C. , Nafisah Ibrahim , Wood Henry M. , Rabbitts Pamela , Berri Stefano
Published: March 2014

Motivation: Current high-throughput sequencing has greatly transformed genome sequence analysis. In the context of very low-coverage sequencing (<0.1×), performing ‘binning’ or ‘windowing’ on mapped short sequences (‘reads’) is critical to extract genomic information of interest for further evaluation, such as copy-number alteration analysis. If the window size is too small, many windows will exhibit zero counts and almost no pattern can be observed. In contrast, if the window size is too wide, the patterns or genomic features will be ‘smoothed out’. Our objective is to identify an optimal window size in between the two extremes.

Results: We assume the reads density to be a step function. Given this model, we propose a data-based estimation of optimal window size based on Akaike’s information criterion (AIC) and cross-validation (CV) log-likelihood. By plotting the AIC and CV log-likelihood curve as a function of window size, we are able to estimate the optimal window size that minimizes AIC or maximizes CV log-likelihood. The proposed methods are of general purpose and we illustrate their application using low-coverage next-generation sequence datasets from real tumour samples and simulated datasets.

Availability and implementation: An R package to estimate optimal window size is available at http://www1.maths.leeds.ac.uk/∼arief/R/win/ .

Contact:  a.gusnanto@leeds.ac.uk

Supplementary information:  Supplementary data are available at Bioinformatics online.
The Wavefront Clock Technique Applied to Current VLBI Systems
Authors: Kiuchi Hitoshi , Kondo Tetsuro
Published: March 2014

A prototype wavefront clock system has been developed for application to current VLBI systems. The reference clock for both the front-end and back-end of a VLBI system is controlled at the observing site according to a calculated a priori delay rate. By using this system, fringe stopping is simultaneously performed on all received frequencies and both the upper side band (USB) and the lower side band (LSB) of a frequency-converter signal. Also, it can be used to reduce the large fringe rate (Doppler frequency) inherent in space VLBI, especially when used with an FX-type correlation processor. This wavefront clock method will be beneficial to users of conventional VLBI systems and will not require any modification. The reference point for the Doppler compensation can be taken at an ideal point, like the center of the Earth. Moreover, it is possible to use it as a pseudo-fringe simulator for checking the correlation processor.
Global Structure of Bimodal Accretion Disks around a Black Hole
Authors: Honma Fumio
Published: March 2014

The global structure of accretion disks around a stellar-mass black hole is examined while taking into account the energy transport by means of diffusion, as well as that by means of radial flow. It is shown that the model can have two types of solutions: In one type, the whole disk is cool and is optically thick; in the other, the disk has a hot optically thin inner region. The structure of the hot inner region of the latter is examined and an analytic formula for the location of the interface of the hot and cold region is obtained. The stability of the latter is also discussed briefly. This behavior of the model can be a possible explanation for the bimodal behavior observed in the X-ray spectra of black hole candidates.
Accretion Disks with a Cloudy Sky — Photon Floater
Authors: Fukue Jun
Published: March 2014

Materials rotating above/below an accretion disk around a central object suffer from the influence of the strong radiation fields of the disk as well as the gravity of the central object. We find that there exists a critical floating height where the vertical gravity of the central object is balanced by the radiation force from the disk, and the materials are photon-floating there. The critical floating height is detemined by the disk effective luminosity Γeff, which is denned by Γeff = (σ/σT)(mp/m)(Ld/LE), where σ and m are the material cross-section and mass, respectively, σT and mp the Thomson cross-section and the proton mass, respectively, and Ld and LE the disk luminosity and the Eddington luminosity, respectively. For small Γeff or large r ( » z) the critical floating height ZF is expressed as zF ˜ 3 rinΓeff, where rin is the inner radius of the disk. The astrophysically important point is that this critical floating height is dynamically stable; hence, materials, such as gas clouds or dust or artificials, suffering from the radiation field of the disk drift toward this floating height. Such floating clouds — photon floaters — above/below the disk partially occults the disk. If the disk sky is cloudy, the observed luminosity becomes irregular. Futhermore, if a cloudy sky is present, the emitted spectrum would be remarkably modified due to reprocessing. A cloudy sky would also produce absorption/emission features. In addition, since the radiation from the disk is scattered by floating clouds at a critical floating height, the disk appears as if its thickness had become zF. The weather environment, such as a cloudy or dusty sky, changes the disk appearance significantly.
Discovery of an Abundance Gradient in the Central Region of the Virgo Cluster
Authors: Matsumoto Hironori , Koyama Katsuji , Awaki Hisamitsu , Tomida Hiroshi , Tsuru Takeshi , Mushotzky Richard , Hatsukade Isamu
Published: March 2014

We present the ASCA results of spatially resolved X-ray spectra in the central regions of the Virgo cluster, near to the central elliptical galaxy M87 and 40' northwest of M87 (M87 NW). Since the spectra of the M87 region is complex, an adequate fit requires at least two thin thermal-plasma components. The temperatures of the hot and cool components are approximately 3.0 and 1.3 keV, respectively, and the temperature of these components are both nearly constant over the central 10' radius from the center of M87. The spectrum of M87 NW, on the other hand, can be well fitted by a single thin thermal-plasma model of ∼ 2.7 keV temperature. The abundances of Fe, Si, and S rise towards the center of M87, though the ratios of Si/Fe and S/Si remain constant. We also found, contrary to the Einstein Observatory's results, that the abundance ratio of oxygen to iron (O/Fe) is smaller than the solar value.
ASCA View of Our Galactic Center: Remains of Past Activities in X-Rays?
Authors: Koyama Katsuji , Maeda Yoshitomo , Sonobe Takashi , Takeshima Toshiaki , Tanaka Yasuo , Yamauchi Shigeo
Published: March 2014

Detailed X-ray images and spectra of the galactic-center region up to 10 keV were obtained with ASCA. Diffuse thermal-emission with distinct Kα lines from highly ionized ions of various elements has confirmed the presence of an extended high-temperature plasma. The fluorescent X-ray emission from cold iron atoms in molecular clouds was also found, possibly due to irradiation by X-rays from the center, which was bright in the past, but is presently dim. The results suggest that the galactic center exhibited intermittent activities with a time-averaged energy generation rate comparable to Seyfert nuclei, a class of active galactic nuclei.
Emission-Line Profiles from Be-Star Envelopes with m = 1 Perturbation Patterns
Authors: Okazaki Atsuo T.
Published: March 2014

We have studied the variations in the Balmer-line profiles from Be-star disks with eccentric (i.e., m = 1) perturbation patterns. In order to examine the effects of oscillations on the line profiles, we assumed that the nonlinear perturbation patterns are similar to the linear m = 1 eigenfunctions. In addition, we assumed that the source function is constant over the entire disk. Based on these assumptions, we computed the optically-thick line profiles for various values of the disk parameters. We found that the line-profile variability due to the m = 1 perturbation patterns agrees well with the observed V/R variability. We also found that the amplitude of the profile shift associated with the V/R variation is sensitive to the density gradient in the radial direction. In particular, disks in which the local density decreases as steeply as r−3 exhibit remarkable variabilities like the observed V/R variations. These variabilities occur for a wide range of disk sizes and line optical depths.
Vertical Structure of Magnetohydrodynamic Turbulence in Accretion Disks
Authors: Nakao Yasushi
Published: March 2014

The vertical structure of magnetohydrodynamic turbulence in accretion disks with density stratification is considered by applying one-point closure modeling of the turbulence. The transport equations of turbulent kinetic energy (K), turbulent magnetic energy (KW ), and density variance (KD) are solved simultaneously under the assumptions of isothermal disks and no global magnetic field. Moreover, the turbulence in the disk is assumed to be homogeneous in the horizontal plane. The imposed boundary conditions are: (i) both the turbulent energy K and the density variance KD do not escape from the disk through the surface; (ii) on the other hand, the escape of turbulent magnetic energy KW is considered phenomenologically. The results show that both K and KW /ρM (magnetic energy per unit mass) increase with height due to turbulent diffusion. It follows that the so-called α-value generally increases from the equator of disks toward the surface, though it decreases, due to the escape of magnetic fields, in a region rather close to the surface. The results further show that the magnetic energy is larger than the turbulent kinetic energy over a wide range of the disk height, implying that the main contributor to angular-momentum transport and viscous heating in the disks is the magnetic fields.
A Seismic Solar Model Deduced from the Sound-Speed Distribution and an Estimate of the Neutrino Fluxes
Authors: Shibahashi Hiromoto , Takata Masao
Published: March 2014

We have deduced the density, pressure, temperature, and hydrogen profiles in the solar interior by solving the basic equations governing the stellar structure with the imposition that the sound-speed profile is that determined by the helioseismic data of Libbrecht et al. (1990; AAA 52.080.103) and Jiménez et al. (1988; AAA 45.080.041). This approach is completely different from that of the standard solar model, and is based on more experimentally well-determined data. We solved the equations by requiring that the mass and mean molecular weight at the surface match the solar mass and a certain fixed value, respectively, as the outer boundary conditions. Together with these conditions and the appropriate inner boundary conditions, these equations were reduced to a boundary-value problem. We examined whether the luminosity at the surface matches the observed value. The error levels were estimated by a Monte-Carlo simulation with Gaussian noise on the sound-speed profile. The thus-constructed seismic model marginally satisfies the luminosity condition, L(R⊙) = L⊙, at the 3σ level. Using this seismic model, we estimated the neutrino fluxes, and found that the 8B neutrino flux is about 60% of that of the standard solar model. This model does not seem to contradict the Kamiokande neutrino detection experiment. The 7Be neutrino flux of the model is about 20% smaller than the standard solar model, and the pp-neutrino flux of the model is almost the same as that of the standard solar model. We estimated the total neutrino capture rate of the chlorine experiment (Homestake) and that of the gallium experiments (GALLEX and SAGE), except for a contribution from the CNO cycle, by scaling the capture rates based on the standard solar model. The thus-estimated capture rates are 5.62 SNU and 117 SNU, respectively, and are higher than those observed at the 3σ error level.
Unresolved X-Ray Emission from the Galactic Ridge with ASCA
Authors: Yamauchi Shigeo , Kaneda Hidehiro , Koyama Katsuji , Makishima Kazuo , Matsuzaki Keiichi , Sonobe Takashi , Tanaka Yasuo , Yamasaki Noriko
Published: March 2014

We report on the ASCA results of hard X-ray imaging and spectroscopic observations of the galactic ridge (the Scutum arm region). The bulk of X-rays in the field of view could not be explained by an integrated emission of resolved sources, indicating that most of the galactic-ridge X-rays are due to a diffuse thin hot plasma. The X-ray luminosity of discrete sources contributing to the galactic-ridge emission was estimated to be less than ∼2x1033 erg s−1 in the 2–10 keV energy band. Emission lines from helium-like Si, S, and Fe ions were confirmed in the spectra, which means that the galactic ridge X-ray emission can not be explained by a single temperature ionization equilibrium plasma model. We give some constraints on the origin of the galactic-ridge emission.
ASCA Observation of a Possible X-Ray Counterpart of the 1992 May 1 Gamma-Ray Burst
Authors: Murakami Toshio , Shibata Ryo , Ogasaka Yasusi , Yoshida Atsumasa , Hurley Kevin , Li Peng , Kouveliotou Chryssa , Fishman Gerald J.
Published: March 2014

A probable X-ray counterpart of the 1992 May 1 gamma-ray burst was observed with ASCA. This burst was first observed with the 3rd interplanetary network, which consisted of BATSE, Ulysses, and PVO, and was localized to a small error box. Then, 18 days after the burst, ROSAT discovered a weak X-ray source in the error box, and later ROSAT HRI and PSPC observations determined the spectrum and refined the position. ASCA observed this source on 1995 April 10. Its 0.5–10.0 keV spectrum appears to be hard, and is heavily absorbed at low energies. The amount of absorption is consistent with the galactic hydrogen column density in this direction. This suggests that the X-ray source is quite distant, and might not be a field star or a supernova remnant in the galactic disk. Recently, IR observations at KECK found a galaxy in the error box, which seems to be consistent with the ASCA results.
Detection of Hard X-Ray Emission from Mkn 463
Authors: Ueno Shiro , Koyama Katsuji , Awaki Hisamitsu , Hayashi Ichizo , Blanco Philip R.
Published: March 2014

We present the results of ASCA observations of the Seyfert galaxy Mkn 463. We find that the 1–10 keV X-ray spectrum consists of at least two components: soft and hard. We have found no evidence for a strong Fe-K fluorescent line (equivalent width < 670 eV). The soft component dominates below 4 keV and has a steep slope; the 0.2–4 keV flux is consistent with that determined from Einstein observations. It would appear that this soft X-ray emission comes from a distinct thermal component. The hard component, which has been detected for the first time by ASCA, is found only above 4 keV with an apparent flat spectral slope. We argue that most of these hard X-rays are emitted directly from the nucleus of Mkn 463E, suffering a heavy absorption along our line of sight. For an assumed typical photon index of 1.7, the absorption column and intrinsic luminosity are estimated to be (1.8 ± 0.4) × l023 cm−2 and 1 × 1043 erg s−1. This hard X-ray luminosity is much less than that expected on the basis of Mkn 463E's optical and infrared properties.
X-Ray Spectroscopy of Centaurus X-3 with ASCA over an Eclipse
Authors: Ebisawa Ken , Day Charles S. R. , Kallman Timothy R. , Nagase Fumiaki , Kotani Taro , Kawashima Kenji , Kitamoto Shunji , Woo Jonathan W.
Published: March 2014

The X-ray binary pulsar Cen X-3 was observed with the ASCA satellite over an entire binary eclipse. With unprecedented energy resolution at the iron K-energy band (FWHM ∼ 2%), three iron emission lines at 6.4 keV, 6.7 keV, and 6.97 keV were clearly resolved. At lower energies, lines from hydrogenic ions of Ne, Mg, Si, and S were also observed. Spectral variations over the eclipse were studied, in particular variations of the iron emission lines. Although the intensity of the 6.4 keV line, which is due to fluorescence from low ionized iron, decreased about one order of magnitude during the eclipse, the intensity drop of the 6.7 and 6.97 keV lines, which are respectively from Fe XXV and Fe XXVI, was at most a factor of three. This, confirming the conjecture by Nagase et al. (1992, AAA56.117.175), indicates that the 6.4 keV fluorescent line is emitted from the region close to the neutron star while the highly photoionized plasma which emits 6.7 and 6.97 keV lines is more extended than the size of the companion star (∼ 12 R⊙). The 6.4 keV line equivalent-width did not show a large variation over the eclipse, and was 75–145 eV. The dense Alfvén shell or an optically thick accretion disk is a likely candidate for reprocessing the fluorescent iron line. From the intensity ratio of the 6.7 and 6.97 keV lines during the eclipse, the ionization parameter of the photoionized plasma is estimated as ξ ∼ 103.4. The size and the density of the plasma are estimated as ∼ 16 R⊙ and ∼ 1.3 × 1011 cm−3, respectively. It is suggested that a lower ionization state is dominated in the pre-eclipse phase, since the 6.7 and 6.97 keV lines were not clearly seen and other K-lines from lighter elements were strong.
Radiative Disk Winds under Radiation Drag
Authors: Tajima Yukiko , Fukue Jun
Published: March 2014

We consider accretion-disk winds, which are driven by disk radiation fields, while taking into account radiation drag as well as radiation pressure. The winds ejected from the accretion disk are exerted by the influence of the radiation pressure from the central object and the accretion disk, itself. We calculate, under the near-disk approximation, the trajectories of particles for various parameters, such as the initial radii and the luminosities of the central object and the disk. We then obtain the conditions which determine whether particles escape or not. These particles moving in intense radiation fields with a velocity of the order of the light speed are also affected by radiation drag. Due to the radiation-drag effect, dragged particle winds are hard to escape compared with the case of non-dragged winds. When they are captured by the gravitational force of the central object, particles float at some typical height above the accretion disk while being balanced by the vertical gravitational force of the central object and the force of the disk radiation pressure. In such a case, the ejected material becomes coronal gas spreading above/below the disk. When the winds blow, on the other hand, the trajectories of the particles tend to widen in the radial direction, since the winds are dragged by the disk radiation fields and gain angular momentum.
Near-Infrared Surface-Photometry of Edge-on Scd Galaxies, NGC 3556 and NGC 4244
Authors: Kodaira Keiichi , Yamashita Takuya
Published: March 2014

Near-infrared images in the J and K′ bands of two edge-on late-type galaxies, NGC 3556 and NGC 4244, were obtained with the newly developed common-use instrument for infrared imaging and spectroscopy at the Okayama Astrophysical Observatory (OASIS). These images were analyzed to yield the surface-photometric and model parameters for the global structure of these Scd galaxies. NGC 3556 shows a disk and a bar-like structure, both of which have an approximately exponential surface-brightness distribution. The absorption feature of NGC 3556 is complex, and only the most prominent central dark lane of AJ < 0.5 was taken into the modeling. NGC 4244 comprises a disk and a weak bulge, both having an approximately exponential surface-brightness distribution, suffering under negligible internal absorption by a faint dark lane of AJ < 0.1. Global models of the 3-D emissivity structure and absorption layer have been constructed to reproduce the observed main features. The global models indicate that both galaxies are optically thin in the V band when seen face on (τ0,v < 0.4), with the reservation of a possible presence of locally opaque structures in NGC 3556. Brief discussions are given concerning the insufficiency of simple absorption-layer models and the strong contrast between the two Scd galaxies regarding their interstellar matter and star-forming activities.
Two-Dimensional Decomposition of a Disky Elliptical Galaxy, NGC 4621
Authors: Mizuno Takao , Oikawa Ken-Ichi
Published: March 2014

We decomposed two-dimensionally an elliptical galaxy, NGC 4621, which shows deviations from the brightness distribution of the r1/4-law. We have found that its brightness distribution can be reproduced by three components possessing constant ellipticities with an rms 0.085 Bs (the sky brightness) of the residuals in the circular region of radius r ≤ 200″, except for r < 1″. The component obeying the r1/4 -law has 62% of the total light, and, hence, is the main body of this elliptical galaxy. The component obeying the exponential law is considered to be a disk, because the rotational velocity, 120 km s(−1), is comparable to that of a disk galaxy. The light ratio of the disk component to the main body is 0.25, about half of which is in S0 galaxies. It is justified that NGC 4621 be classified not as a disk galaxy, but as elliptical. The envelope component is circular and has 22% of the total light. This circular component is considered to be spherical three-dimensionally and to be a halo. The inclination angle of the disk component is estimated to be 65° from its ellipticity 0.43. The main body is inferred in terms of the probabilities to be an oblate spheroid from the fact that the position angle of its major axis coincides with that of the disk, and its rotational velocity is comparably as large as that of a disk galaxy. If the main body is an oblate spheroid, the ratio of its intrinsic principal axes is derived to be 0.64 from its apparent axis ratio 0.72 and its inclination angle 65°.
Thermodynamic Enhancement of Nuclear Reactions in Dense Stellar Matter
Authors: Ichimaru Setsuo , Kitamura Hikaru
Published: March 2014

An enhancement in the rates of nuclear reactions in dense matter is approached through calculations of increments between the Coulombic chemical potentials before and after the reactions. The formalism is applied to specific cases of the p-p reactions in the solar interior and of the 12C-12C reactions in a white-dwarf progenitor of a supernova; the dependence of the resultant enhancement factors on the relative abundances of the elements in the outgoing channels is thereby illustrated. The effects of plasma screening in the p-p reactions on the solar 8B neutrinos are examined.
Intergalactic Absorption Due to Extended Gaseous Clouds at High Redshifts
Authors: Denda Kiyomi , Ikeuchi Satoru
Published: March 2014

In order to examine the line-blanketing effect due to gaseous clouds at high redshifts, we have calculated the ionization states of gas clouds of subgalactic mass scale exposed to a UV radiation field that can reproduce the ionization states of the Lyman limit systems (LLSs) along the line of sight to quasar HS 1700 + 6416. We also adopted the integrated UV radiation from the observed quasars modified by the intervening absorption due to the Lyman α forest and LLSs as an ionizing spectrum. Our photoionization models can explain the observed HI column-density distribution, the observed CIV/HI ratio and the observed optical depths of HI and HeII. We conclude that the integrated UV background models can well explain the ionization states of both the IGM and Lyman α clouds at z ∼ 2–3. The gaseous mass of the Lyman α clouds follows a power-law form as dn/dMc ∼ Mc-δ with δ ∼ 2–2.5 in the 108 – 1011M⊙ range. The majority of the dark baryon probably consists of the IGM.
Distance Measurement of Galaxies to a Redshift of ∼ 0.1 Using the CO-Line Tully-Fisher Relation
Authors: Sofue Yoshiaki , Schöniger Franz , Honma Mareki , Tutui Yoshinori , Ichikawa Takashi , Wakamatsu Ken-ichi , Kazes Ilya , Dickey John
Published: March 2014

We report on the first results of a long-term project to derive the distances of galaxies at cosmological distances by applying the CO-line width–luminosity relation. We have obtained deep CO-line observations of galaxies at redshifts of up to cz ∼ 29000 km s-1 using the Nobeyama 45-m mm-wave telescope; also, some supplementary data were obtained using the IRAM 30-m telescope. We have detected CO-line emission from several galaxies, and used their CO-line widths to estimate the absolute luminosities based on the line-width–luminosity relation. In order to obtain photometric data and an inclination correction, we also performed optical imaging observations of the CO-detected galaxies using the CFHT 3.6-m telescope at high resolution. The radio and optical data have been combined to derive the distance moduli and distances of the galaxies; also, the Hubble ratios were estimated for these galaxies. We propose that the CO-line width–luminosity relation can be a powerful method to derive the distances of galaxies to redfhifts of z ∼ 0.1, and to derive the Hubble ratio within a significant volume of the universe.
Uniformity in the Temperature and Metallicity of the X-Ray Emitting Gas in the Abell 1060 Cluster of Galaxies
Authors: Tamura Takayuki , Day Charles S. , Fukazawa Yasushi , Hatsukade Isamu , Ikebe Yasushi , Makishima Kazuo , Mushotzky Richard F. , Ohashi Takaya , Takenaka Kazuhiro , Yamashita Koujun
Published: March 2014

The results from ASCA observations of the Abell 1060 cluster of galaxies are presented. Spatially sorted X-ray spectra were used to derive the distributions of the temperature and metallicity in the X-ray emitting gas of the cluster. Within ∼ 20′ (or 400 kpc assuming H0 = 50 km s−1 Mpc−1) of the cluster center, the gas temperature has been found to be radially constant at 3.1+0.3−0.5 keV (or 3.1 ± 0.2 keV within ∼ 10′), and the 2–10 keV luminosity was estimated to be 2 × 1043 erg s−1. An upper limit on the cool emission component at the cluster center was derived to be 6 × 1041 erg s−1 in 0.5–3 keV, assuming that it has a temperature of 1 keV. Although the metallicity is consistent with being radially constant at 0.3 relative to solar value, the present observations do not constrain the abundance well beyond 10′, allowing values in the range from 0.2 to 0.4 solar value. There is some indication that O, Ne, and Si are more abundant than Fe and Ni, when compared to the solar-abundance ratios. These results suggest the importance of galactic winds driven by type-II supernovae during the early phase of galaxy formation. In comparison with the Centaurus and Virgo clusters, discussions are made concerning the possible role of the cD galaxy in generating a metal concentration and a cool X-ray component at the cluster center.
Fokker-Planck Models of Star Clusters with Anisotropic Velocity Distributions II. Post-Collapse Evolution
Authors: Takahashi Koji
Published: March 2014

The evolution of spherical single-mass star clusters driven by two-body relaxation was followed beyond core collapse by numerically solving the orbit-averaged Fokker-Planck equation in energy–angular momentum space. The heating effect by three-body binaries was incorporated in the Fokker-Planck models. The development of velocity anisotropy after the core collapse is discussed in detail. The anisotropy in the outer regions continues to increase slowly after the collapse. In clusters comprising a relatively small number of stars (N ≲ 10000), the post-collapse expansion is nearly self-similar and the anisotropy at each of inner Lagrangian radii is nearly constant. In clusters comprising a larger number of stars (N ≳ 10000), gravothermal oscillations occur and the anisotropy at each of the inner radii oscillates with the core oscillations. There is no qualitative difference in the nature of the gravothermal oscillations between the isotropic and anisotropic Fokker-Planck models.
Broad-Band X-Ray Observations of the Orion Region with ASCA
Authors: Yamauchi Shigeo , Koyama Katsuji , Sakano Masaaki , Okada Kyoko
Published: March 2014

Broad-band X-ray images and spectra of the Orion Nebula region were obtained with the X-ray satellite ASCA. Fifty two point-like sources were resolved, including the Orion Trapezium. A large fraction of the optical counterparts of the ASCA sources were classified as G–M type stars. Spectral model fits and count ratios (flux ratio between soft and broad bands) revealed that most of the point sources exhibit a high-temperature plasma of ∼2–5 keV. Model fits of the X-ray spectra from extended regions around the Orion Nebula (M42), the reflection nebula NGC 1977, and the sky between these nebulae required at least two-temperature components of typically 0.7–1 keV and 3–5 keV. From selected high-flux sources, we also found that the model of a 2-temperature thin thermal plasma is more likely than that of a single-temperature. X-ray light curves from these sources were time variable, but showed no large flares. We thus suggest that the hard X-rays are generated even in relatively quiescent states.
Deneb's Light-Element Abundances Revisited
Authors: Takeda Yoichi , Takada-Hidai Masahide , Kotake Junko
Published: March 2014

A revised non-LTE analysis of Deneb (A2 Ia supergiant), based on our new observational data, was performed in order to reinvestigate its photospheric abundances of He, C, N, O, Na, and S by using the model atmosphere (Teff = 9000 K, log g = 1.5), which satisfies the ionization equilibria of C/S and has a Teff lower by 1000 K than that adopted in the previous work of Takeda (1994; AAA 61.114.112). Owing to this model change, the abundance of He has turned out to be nearly normal on the average, in contrast to the conclusion in that old study, which suggested a considerable deficiency. However, the abundances from individual HeI lines show a rather large diversity with an apparent wavelength-dependence, which remains to be explained. Regarding the abundances of C, N, O, Na, and S relative to the Sun, C is conspicuously underabundant by ∼ 0.8 dex, N, Na, and S show a moderate excess of 0.3–0.4 dex, and O seems to be mildly deficient by ∼ 0.3 dex; this abundance pattern appears to conform to the common tendency seen with other supergiants in this temperature range.
Global Structures of Advection-Dominated Two-Temperature Accretion Disks
Authors: Nakamura Kenji E. , Matsumoto Ryoji , Kusunose Masaaki , Kato Shoji
Published: March 2014

Models of steady transonic global flows of optically thin, advection-dominated, two-temperature accretion onto black holes have been constructed. The physical quantities integrated over the vertical direction are treated with the Shakura-Sunyaev type α-viscosity. Bremsstrahlung and Compton cooling are considered, but synchrotron-Compton cooling is not taken into account. It has been found that the electron temperature in the inner part of the disk is fairly high in our model, because the surface density is low and the cooling there is rather inefficient. We have obtained Ṁcrit above which no steady solution is allowed, and have found that it is necessary to consider the relativistic cooling effect in the state that the electron temperature is higher.
Far-Infrared [CII] Line Observation of the Galactic Plane by IRTS
Authors: Makiuti Sin'itirou , Shibai Hiroshi , Okuda Haruyuki , Nakagawa Takao , Matsuhara Hideo , Hiromoto Norihisa , Okumura Ken'ichi
Published: March 2014

A detailed map of the distribution of the [CII] 158 μm line intensity from the galactic plane around l = 50° was obtained by the Far-Infrared Line Mapper (FILM) on board the Infrared Telescope in Space (IRTS). The distribution of the [CII] emission is similar to that of the far-infrared continuum emission. There are a number of discrete sources, most of which correspond to known objects, such as compact HII regions and molecular clouds, near to the galactic plane. Moreover, an extended component concentrated in the galactic plane was found, and its distribution does not clearly depend on the galactic longitude in the observed area. This extended component decreases rapidly as the galactic latitude increases. The FWHM of this component is about 2.°6 in the galactic latitude. This is larger than that of the CO (J = 1 → 0) intensity, but is much smaller than that of the HI 21 cm intensity.
DI Ursae Majoris: Discovery of an Extreme ER UMa-Type Dwarf Nova with the Shortest Orbital Period
Authors: Kato Taichi , Nogami Daisaku , Baba Hajime
Published: March 2014

The long-term, time-resolved CCD photometry of a dwarf nova, DI UMa, has revealed this object to be a peculiar SU UMa-type dwarf nova having both the shortest ever observed superhump period (0.0555 d) and a very short (25 d) supercycle length. These features make DI UMa the fourth established member of a recently discovered small group of dwarf novae, called ER UMa stars or RZ LMi stars, which are now believed to be SU UMa-type dwarf novae with exceptionally high mass-transfer rates. DI UMa in all respects resembles a peculiar dwarf nova RZ LMi, but is more extreme in its short superhump period. The high-incident discovery of objects with such an extreme combination of parameters, which can not be expected from the standard evolution of cataclysmic variables (CVs), should provide a unique tool in probing the long-debated problem concerning the origin of mass-transfer in CVs and a secular alteration between CV subclasses.
BVRI Photometric Light Curves of the Galactic Supersoft X-Ray Source RX J0019.8+2156
Authors: Matsumoto Katsura
Published: March 2014

Photometric observations of the galactic supersoft X-ray source RXJ0019.8+2156 in the B, V, R, and I bands were carried out between July and December of 1995. The observed light curves show periodic variations (Period = 15.85hr) with an amplitude of around 0.5mag in all four bands, while color curves (B – V, V – R, and V – I) show virtually no variation throughout the cycle. We find a secondary minimum which is highly variable in its shape from one cycle to another. The hump before the secondary minimum (phase ∼ 0.3–0.4) is brighter by about 0.1mag compared to that seen after the secondary minimum (phase ∼ 0.6–0.7). The primary minimum appears to be stable in depth on a timescale of several months. Furthermore, changes in brightness of about 0.15mag are observed from one cycle to another without detectable variation in the colors. The time scale of these irregular fluctuations is about one week or shorter.
Accretion-Disk Corona Advected by External Radiation Drag I.
Authors: Watanabe Yoichi , Fukue Jun
Published: March 2014

We examined an accretion-disk corona (β-corona) which is dynamically driven via the radiation drag exerted by a central luminous source and the accretion disk, itself. We adopted the standard α-disk as the disk model. We considered a geometrically thin and optically thin corona and ignored any motion such as wind. When the central source is sufficiently luminous, the specific angular momentum of the corona gas is lost by the radiation drag of the radiation field produced by the central source. As a result, the rotation velocity of the corona gas becomes smaller than a Keplerian one, and the corona gas is advected inward on a dynamical timescale. This new picture concerning the accretion-disk corona — a dynamical disk corona — is a rather universal one. When the accretion disk is luminous, on the other hand, the corona gas tends to corotate with the underlying disk by radiation drag of the radiation field produced by the α -disk. As a result, the advection of the corona gas is suppressed (this is the case of the traditional picture of a stationary disk corona). In addition, the emission-line profiles expected from these advected disk corona can be calculated for a wide variety of parameters. The line profiles are generally double peaked. The separation of two peaks depends on the brightness of the central source as well as the size of the emitting regions. When the central source is brighter, the separation of two peaks becomes smaller.
The Solar Flare of 1992 August 17 23:58 UT
Authors: Takahashi Masaaki , Watanabe Tetsuya , Sakai Jun-ichi , Sakao Taro , Kosugi Takeo , Sakurai Takashi , Enome Shinzo , Hudson Hugh S. , Hashimoto Shizuyo , Nitta Nariaki
Published: March 2014

A small flare (C4.3 in the GOES X-ray class) was well observed by all of the instruments on board Yohkoh. The X-ray light curves have double peaks which are about 5 min apart. Until the first peak from flare onset, four compact areas brighten up in the soft X-ray region, which are aligned almost on one straight line. We regard them as being footpoints of two sets of loops, which are identifiable in soft X-ray images, since their locations match those of hard X-ray sources. Indeed, after the second peak, the temporal behavior of the temperature and emission measure at each point is consistent with the existence of two such loops. Comparing our results with recent MHD simulations, we propose a possible scenario for this flare that is based on the coalescence of two loops.
Mass of the Galaxy Inferred from Outer Rotation Curve
Authors: Honma Mareki , Sofue Yoshiaki
Published: March 2014

Using an outer rotation curve of the Galaxy, we explore the galactic constants Θ0 and R0 and the mass of the Galaxy. We show that Θ0 of 200 km s−1 is more favorable than the IAU standard value of 220 km s−1 , and also show that if Θ0 is smaller than 207 km s−1 the rotation curve beyond 2R0 is declining in Keplerian fashion. In the case of Θ0 = 200 km s−1 and R0 = 7.6 kpc, the total mass and the extent of the Galaxy inferred from the rotation curve are 2.0 ± 0.3 × 1011M⊙ and 15 kpc, respectively. These results may significantly change the previous view of the Galaxy, that its outer region is dominated by a massive dark halo extending out to several tens of kpc.
Re-examination of the Hubble Constant from the Sunyaev-Zel'dovich Effect: Implication for Cosmological Parameters
Authors: Kobayashi Shiho , Sasaki Shin , Suto Yasushi
Published: March 2014

We performed a systematic and comprehensive estimate of the Hubble constant H0 via the Sunyaev-Zel'dovich temperature decrement and X-ray measurements for clusters up to redshift z of 0.541, paying particular attention to its dependence on the density parameter Ω0 , and the cosmological constant λ0 . The resulting values of H0 are largely consistent with that derived from the Cepheid distance for nearby galaxies. We discuss how the angular diameter distance dA vs. z diagram from accurate SZ measurements of high-z clusters is dependent on the values of Ω0 and λ0 .
No Eclipses in A1742-289 Archival Data
Authors: Kennea J. A. , Skinner G. K.
Published: March 2014

It has been suggested that a recently detected galactic center binary X-ray source represents the quiescent state of A1742–289, a transient source which appeared in 1975. We find no evidence for eclipses in the Ariel V RMC data for the transient, suggesting that the binary source is a previously undetected distinct system.
155 Micron Continuum Emission from the Galactic Plane near l = 50 Degrees Observed by IRTS
Authors: Okumura Ken'ichi , Hiromoto Norihisa , Okuda Haruyuki , Shibai Hiroshi , Nakagawa Takao , Makiuti Sin'itirou , Matsuhara Hideo
Published: March 2014

The 155 μ m continuum emission from the galactic plane around l = 50° was observed with an 8′ × 13′ beam by the Far-Infrared Line Mapper (FILM) aboard the Infrared Telescope in Space (IRTS). The observed map noticeably resembles the IRAS 100 μm map. The dust temperature calculated from their flux ratio is almost constant (16–18 K) throughout the observed area, except for the HII regions. The dust temperatures in the HII regions are significantly higher than in the surrounding region; there is a clear boundary between the cold and hot regions. The observed uniformity of the dust temperature, except for in the HII regions, implies that the strength of the average interstellar radiation field (ISRF) along each line of sight is almost constant (i.e., varies by less than a factor of 2) in the observed region of the galactic plane.
Expanding Atmosphere of the M-Type Supergiant in VV Cephei
Authors: Kawabata Shusaku , Saitō Mamoru
Published: March 2014

A search and radial-velocity measurements of forbidden lines were performed on spectrograms of VV Cep at 0.35–0.45 μm taken between 1976 and 1984, which was about half the orbital period around the last eclipse. We identified 13 [FeII] lines, 3 [NiII] lines, and one [CuII] line including at least six new lines on the spectra of VV Cep. The radial velocities of these forbidden lines were independent of the eclipse phase, and differed with respect to the transition probability and excitation potential. The forbidden-line features indicate the presence of gaseous motions expanding from the M-type supergiant with velocities of ∼ 20 km s−1. The mass-loss rate is estimated to be on the order of 10−6M⊙ yr−1.
Electron Temperature of Solar Flares Derived from Helium-Like Sulphur Lines Sulphur Lines
Authors: Yuda Sayuri , Hiei Eijiro , Takahashi Masaaki , Watanabe Tetsuya
Published: March 2014

The maximum temperatures and emission measures reached in solar flares were obtained from helium-like sulphur lines, which were observed by the Bragg Crystal Spectrometer on board Yohkoh. A very weak dependence of the maximum temperature against the soft X-ray intensity was found. Similar multi-thermal characteristics prevailed in flares irrespective of the flare intensity, suggesting that the solar flare is a homogeneous phenomenon in the solar atmospheres.
An Imaging Algorithm Using the Bispectrum in Radio Interferometry
Authors: Katagiri Seiji , Morita Koh-Ichiro , Kawaguchi Noriyuki , Hayakawa Masashi
Published: March 2014

We present a maximum-entropy imaging algorithm using the bispectrum observed with radio interferometers. It is iterative and based on the steepest-ascent method. Imaging simulation tests show that this algorithm can reconstruct more reliable images of weak, extended sources than can the conventional self-calibration method. An example application of this algorithm to data of the Nobeyama Millimeter Array is given.