213 research outputs found
A Micro Molecular Bipolar Outflow From HL Tau
We present detailed geometry and kinematics of the inner outflow toward HL
Tau observed using Near Infrared Integral Field Spectograph (NIFS) at the
Gemini-North 8-m Observatory. We analyzed H2 2.122 um emission and [Fe II]
1.644 um line emission as well as the adjacent continuum observed at a <0".2
resolution. The H2 emission shows (1) a bubble-like geometry to the northeast
of the star, as briefly reported in the previous paper, and (2) faint emission
in the southwest counterflow, which has been revealed through careful analysis.
The emission on both sides of the star show an arc 1".0 away from the star,
exhibiting a bipolar symmetry. Different brightness and morphologies in the
northeast and southwest flows are attributed to absorption and obscuration of
the latter by a flattened envelope and a circumstellar disk. The H2 emission
shows a remarkably different morphology from the collimated jet seen in [Fe II]
emission. The positions of some features coincide with scattering continuum,
indicating that these are associated with cavities in the dusty envelope. Such
properties are similar to millimeter CO outflows, although the spatial scale of
the H2 outflow in our image (~150 AU) is strikingly smaller than the mm
outflows, which often extend over 1000-10000 AU scales. The position-velocity
diagram of the H2 and [Fe II] emission do not show any evidence for kinematic
interaction between these flows. All results described above support the
scenario that the jet is surrounded by an unseen wide-angled wind, which
interacts with the ambient gas and produce the bipolar cavity and shocked H2
emission.Comment: 13 pages, 4 figures, accepted for publication in ApJ
An Artificial Intelligence Technique to Characterizae Surface-Breaking Cracks
A neural network with an analog output is presented to determine the angle of inclination of a surface-breaking crack from ultrasonic backscattering data. A neural network which was trained by the use of synthetic data set to estimate the depth of a crack, assuming that the inclined crack angle is known, was presented earlier[1,2]. In this study, a neural network estimates the angle of inclination of the surface-breaking crack, assuming that the depth of the crack is 2.0mm, by utilizing the waveforms of backscattered signals from the crack. The plate with a surface-breaking crack is immersed in water and the crack is insonified from the opposite side of the plate. The angle of incidence with the normal to the insonified face of the plate is taken to be 18.9°. The neural network is a feed-forward three layered network. The training algorithm is an error back-propagation algorithm which has been discussed in Refs. [3,4]. The theoretical data obtained by the boundary element method are used for the training. The performance of the trained network is tested by synthetic and experimental data
Phenomenological interaction between current quarks
We construct a phenomenological model which describes the dynamical chiral
symmetry breaking (DCSB) of QCD vacuum and reproduces meson spectra. Quark
condensates, the pion decay constant, and meson spectra are well reproduced by
phenomenological interaction which consists of a linear confining potential, a
Coulombic potential, and the 't Hooft determinant interaction. In this model,
the 't Hooft determinant interaction plays a important role not to only
\eta,\eta' mass difference, but other meson masses through DCSB.Comment: 18 pages, LaTe
Neurologic Abnormalities in Workers of a 1-Bromopropane Factory
We reported recently that 1-bromopropane (1-BP; n-propylbromide, CAS Registry no. 106-94-5), an alternative to ozone-depleting solvents, is neurotoxic and exhibits reproductive toxicity in rats. The four most recent case reports suggested possible neurotoxicity of 1-BP in workers. The aim of the present study was to establish the neurologic effects of 1-BP in workers and examine the relationship with exposure levels. We surveyed 27 female workers in a 1-BP production factory and compared 23 of them with 23 age-matched workers in a beer factory as controls. The workers were interviewed and examined by neurologic, electrophysiologic, hematologic, biochemical, neurobehavioral, and postural sway tests. 1-BP exposure levels were estimated with passive samplers. Tests with a tuning fork showed diminished vibration sensation of the foot in 15 workers exposed to 1-BP but in none of the controls. 1-BP factory workers showed significantly longer distal latency in the tibial nerve than did the controls but no significant changes in motor nerve conduction velocity. Workers also displayed lower values in sensory nerve conduction velocity in the sural nerve, backward recalled digits, Benton visual memory test scores, pursuit aiming test scores, and five items of the Profile of Mood States (POMS) test (tension, depression, anxiety, fatigue, and confusion) compared with controls matched for age and education. Workers hired after May 1999, who were exposed to 1-BP only (workers hired before 1999 could have also been exposed to 2-BP), showed similar changes in vibration sense, distal latency, Benton test scores, and depression and fatigue in the POMS test. Time-weighted average exposure levels in the workers were 0.34â49.19 ppm. Exposure to 1-BP could adversely affect peripheral nerves or/and the central nervous system
Optimal Spin Basis in Polarized Photon Linear Colliders
We analyze the spin correlations of the top quark pairs produced at Photon
Linear Colliders. We employ the circular polarized photon beams and general
spin basis for the top quark pair. We consider general spin bases to find a
strong spin correlation between produced top quark and anti-top quark. We show
the cross-section in these bases and discuss the characteristics of results.Comment: RevTeX, 16 pages, 6 figures, psfig.sty and here.sty are require
Differential roles of orexin receptor-1 and -2 in the regulation of Non-REM and REM sleep
éæȹ性ćŠć»èŹäżć„ç 究ćć»ćŠçł»Orexin-A and orexin-B are hypothalamic neuropeptides that play critical roles in the maintenance of wakefulness. Intracerebroventricular (ICV) administration of orexin-A has been shown to promote wakefulness and suppress both rapid eye movement (REM) sleep and non-REM (NREM) sleep through the orexin receptor-1 (OX1R) and orexin receptor-2 (OX2R). Here, we elucidated the differential roles of orexin receptors in the regulation of sleep and wakefulness by comparing the effects of ICV orexin-A administration in wild-type, OX1R, and OX2R mice. The effects of orexin-A on wakefulness and NREM sleep were significantly attenuated in both knock-out mice as compared with wild-type mice, with substantially larger attenuation in OX2R mice than in OX1R mice. These results suggest that although the OX2R-mediated pathway has a pivotal role in the promotion of wakefulness, OX1R also plays additional roles in promoting arousal. In contrast, suppression of REM sleep by orexin-A administration was slightly and similarly attenuated in both OX1R and OX2R mice, suggesting a comparable contribution of the two receptors to REM sleep suppression. Histological studies demonstrated differential distributions of each receptor subtype in distinct neuronal populations with specific neurotransmitter identities in brainstem cholinergic/monoaminergic neurons. In the laterodorsal tegmental and pedunculopontine tegmental nuclei especially, cholinergic neurons exclusively expressed OX1R mRNA, but OX2R mRNA was expressed mainly in GABAergic putative interneurons. Thus, each orexin receptor subtype plays differential roles in gating NREM and REM sleep through distinct neuronal pathways. © 2011 by the authors
Nuclear Photoabsorption at Photon Energies between 300 and 850 Mev
We construct the formula for the photonuclear total absorption cross section
using the projection method and the unitarity relation. Our treatment is very
effective when interference effects in the absorption processes on a nucleon
are strong. The disappearance of the peak around the position of the
resonance in the nuclear photoabsorption can be explained with the cooperative
effect of the interference in two-pion production processes,the Fermi motion,
the collision broadenings of and , and the pion distortion in the
nuclear medium. The change of the interference effect by the medium plays an
important role.Comment: 22pages,7figures,revtex
Polarimetric Imaging of Large Cavity Structures in the Pre-transitional Protoplanetary Disk around PDS 70: Observations of the disk
We present high resolution H-band polarized intensity (PI; FWHM = 0."1: 14
AU) and L'-band imaging data (FWHM = 0."11: 15 AU) of the circumstellar disk
around the weak-lined T Tauri star PDS 70 in Centaurus at a radial distance of
28 AU (0."2) up to 210 AU (1."5). In both images, a giant inner gap is clearly
resolved for the first time, and the radius of the gap is ~70 AU. Our data show
that the geometric center of the disk shifts by ~6 AU toward the minor axis. We
confirm that the brown dwarf companion candidate to the north of PDS 70 is a
background star based on its proper motion. As a result of SED fitting by Monte
Carlo radiative transfer modeling, we infer the existence of an optically thick
inner disk at a few AU. Combining our observations and modeling, we classify
the disk of PDS 70 as a pre-transitional disk. Furthermore, based on the
analysis of L'-band imaging data, we put an upper limit mass of companions at
~30 to ~50MJ within the gap. Taking account of the presence of the large and
sharp gap, we suggest that the gap could be formed by dynamical interactions of
sub-stellar companions or multiple unseen giant planets in the gap.Comment: accepted by APJ
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