134 research outputs found
A New Test for the Absorption Mechanism of GPS Radio Sources Using Polarization Properties
We consider the use of polarization properties as a means to discriminate
between Synchrotron Self-Absorption (SSA) and Free--Free Absorption (FFA) in
GHz-Peaked Spectrum (GPS) sources. The polarization position angle (PA) of
synchrotron radiation at high frequencies for the optically thin regime is
perpendicular to the magnetic field, whereas it is parallel to the magnetic
field at low frequencies for the optically thick regime. Therefore, SSA
produces a change in PA of across the spectral peak, while FFA
does not result in such a change. We analyzed polarization data from VLA
observations for six GPS sources to see if such a change in PA was present. Our
results indicate that there is no significant evidence for change
in PA across the spectral peak, suggesting that FFA is more likely than SSA for
low-frequency cutoffs in these sources
The Autonomous System Architecture of the Small SAR Satellite Operation System and On-Orbit Autonomous Operation Experiences
We are developing a small SAR (Synthetic Aperture Radar) satellite for our commercial solution business. Our goal is to deploy at least 30 small SAR satellites in orbit and enable frequent and persistent observations until the Mid 2020s. We launched the satellite on 15th December 2020 by Rocket Lab\u27s Electron. We waited for a month until we took the first image to confirm the complete evacuation of the residual air and contaminations to prevent any hazardous electrical discharge. We took the first image on 8th February. The satellite is now operating in a fine state and acquiring images requested by the customers. We will make six satellite constellation until 2023. We also describe our system architecture including our solution business and the satellite development. Our business development team and the satellite development team are communicating with each other for adequate system architecture and agile satellite development. Our business development team acquires many novel needs from our customers. One of our goals is an agile reflection of the user\u27s needs for the satellite development. We are now establishing a process and an organization to extract those business needs, analyze them and identify the key requirements for the satellite performances and functions. We believe that one important challenge is to achieve application layer integration from a customer business system to a satellite on-board software through solution platform, data platform, satellite control ground system, and the satellite itself. We try to harmonize the software and information processes of the application layer, although the platform where the application is located, the organization where staffs belong, and their culture are different. We wish our activities contribute to our small satellite community or ecosystem and a system architecture including component suppliers, communication service providers, and data processing service providers
A Helical Magnetic Field in the Jet of 3C 273
Both in the Faraday Rotation Measure and the intrinsic polarization angle,
new features are revealed to indicate a helical magnetic field operating along
the jet of the bright active galactic nuclei 3C 273. The helical field has been
suggested to be related to the formation and collimation of jets by
magnetohydrodynamic models. The distribution of the RM shows a systematic
gradient with respect to the jet axis, which is expected by a helical magnetic
field. In addition, the helical field can consistently explain two types in the
direction of the projected magnetic field: parallel and perpendicular to the
jet axis. Further, if the helical magnetic field is generated by winding up of
an initial field by rotation of the accretion disk, we can uniquely determine
the direction of the disk rotation, since the jet is approaching us.Comment: 7 pages, 5 figures, PASJ Letters in pres
Distribution of Faraday Rotation Measure in Jets from Active Galactic Nuclei II. Prediction from our Sweeping Magnetic Twist Model for the Wiggled Parts of AGN Jets and Tails
Distributions of Faraday rotation measure (FRM) and the projected magnetic
field derived by a 3-dimensional simulation of MHD jets are investigated based
on our "sweeping magnetic twist model". FRM and Stokes parameters were
calculated to be compared with radio observations of large scale wiggled AGN
jets on kpc scales. We propose that the FRM distribution can be used to discuss
the 3-dimensional structure of magnetic field around jets and the validity of
existing theoretical models, together with the projected magnetic field derived
from Stokes parameters. In the previous paper, we investigated the basic
straight part of AGN jets by using the result of a 2-dimensional axisymmetric
simulation. The derived FRM distribution has a general tendency to have a
gradient across the jet axis, which is due to the toroidal component of the
magnetic field generated by the rotation of the accretion disk. In this paper,
we consider the wiggled structure of the AGN jets by using the result of a
3-dimensional simulation. Our numerical results show that the distributions of
FRM and the projected magnetic field have a clear correlation with the large
scale structure of the jet itself, namely, 3-dimensional helix. Distributions,
seeing the jet from a certain direction, show a good matching with those in a
part of 3C449 jet. This suggests that the jet has a helical structure and that
the magnetic field (especially the toroidal component) plays an important role
in the dynamics of the wiggle formation because it is due to a current-driven
helical kink instability in our model.Comment: Accepted for publication in Ap
Recombinant human FGF-2 for the treatment of early-stage osteonecrosis of the femoral head: TRION, a single-arm, multicenter, Phase II trial
Aim: This study aimed to evaluate the 2-year outcomes from a clinical trial of recombinant human FGF-2 (rhFGF-2) for osteonecrosis of the femoral head (ONFH). Patients & methods: Sixty-four patients with nontraumatic, precollapse and large ONFHs were percutaneously administered with 800 μg rhFGF-2 contained in gelatin hydrogel. Setting the end point of radiological collapse, we analyzed the joint preservation period of the historical control. Changes in two validated clinical scores, bone regeneration and safety were evaluated. Results: Radiological joint preservation time was significantly higher in the rhFGF-2 group than in the control group. The ONFHs tended to improve to smaller ONFHs. The postoperative clinical scores significantly improved. Thirteen serious adverse events showed recovery. Conclusion: rhFGF-2 treatment increases joint preservation time with clinical efficacy, radiological bone regeneration and safety
Age-specific serum anti-Müllerian hormone concentration in Japanese women and its usefulness as a predictor of the ovarian response
Purpose: To compare the ovarian response predictive ability of anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH), and estradiol (E2) and to determine the age-specific distribution of serum AMH concentrations of Japanese women.
Methods: This was a multicenter (four-site), observational, analytic, cross-sectional Japanese study consisting of two parts: Study 1 (the prediction of the ovarian response of 236 participants who were undergoing controlled ovarian stimulation [COS]) and Study 2 (the distribution of the AMH concentration with an assay of 417 healthy women who were aged 20-49 years and who had normal menstrual cycles).
Results: The AMH had a significantly higher predictive value for the normal and high responders than FSH and E2 as a stronger correlation between the ovarian response and AMH was observed than for FSH and E2. The serum AMH concentration decreased proportionally with age.
Conclusion: The AMH concentration correlated well with the oocyte count in the patients who were undergoing COS for in vitro fertilization and was shown to predict the risk of ovarian hyperstimulation syndrome among these patients
Distribution of Faraday Rotation Measure in Jets from Active Galactic Nuclei I. Prediction from our Sweeping Magnetic Twist Model
Using the numerical data of MHD simulation for AGN jets based on our
``sweeping magnetic twist model'', we calculated the Faraday rotation measure
(FRM) and the Stokes parameters to compare with observations. We propose that
the FRM distribution can be used to discuss the 3-dimensional structure of
magnetic field around jets, together with the projected magnetic field derived
from the Stokes parameters. In the present paper, we supposed the basic
straight part of AGN jet, and used the data of axisymmetric simulation. The FRM
distribution we derived has a general tendency to have gradient across the jet
axis, which is due to the toroidal component of the helical magnetic field
generated by the rotation of the accretion disk. This kind of gradient in the
FRM distribution is actually observed in some AGN jets (e.g. Asada et al.
2002), which suggests helical magnetic field around the jets and thus supports
our MHD model. Following this success, we are now extending our numerical
observation to the wiggled part of the jets using the data of 3-dimensional
simulation based on our model in the following paper.Comment: Accepted for publication in Ap
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