Suzaku Observation of the RCW86 Northeastern Shell

This paper reports the Suzaku results on the northeast shell of RCW 86. With the spatial and spectral analysis, we separated the X-rays into three distinct components; low (kT_e~0.3keV) and high (kT_e~1.8keV) temperature plasmas and a non-thermal component, and discovered their spatial distributions are different from each other. The low temperature plasma is dominated at the east rim, whereas the non-thermal emission is the brightest at the northeast rim which is spatially connected from the east rim. The high temperature plasma, found to contain the ~6.42keV line (K alpha of low-ionized iron), is enhanced at the inward region with respect to the east rim and has no spatial correlation with the non-thermal X-ray (the northeast). The Fe-Kalpha line, therefore, is not related to the non-thermal emission but originates from Fe-rich ejecta heated to the high temperatures by the reverse shock. Since the metal abundances of the low temperature plasma are sub-solar, the most possible origin of this component is interstellar medium heated by a blast wave. The non-thermal X-ray, which has a power-law index of ~2.8, is likely to be synchrotron emission. A possible scenario to explain these morphologies and spectra is: A fast moving blast wave in a thin cavity of OB association collided with a dense interstellar medium or cloud at the east region very recently. As the result, the reverse shock in this interior decelerated, and arrived at the Fe-rich region of the ejecta and heated it. In the northeast rim, on the other hand, the blast wave is still moving fast, and accelerated high energy electrons to emit synchrotron X-rays.Comment: 13 pages, 5 figures (9 figure files), accepted for publication in PAS

A new heterozygous compound mutation in the CTSA gene in galactosialidosis

Galactosialidosis is an autosomal recessive lysosomal storage disease caused by the combined deficiency of lysosomal β-galactosidase and neuraminidase due to a defect in the protective protein/cathepsin A. Patients present with various clinical manifestations and are classified into three types according to the age of onset: the early infantile type, the late infantile type, and the juvenile/adult type. We report a Japanese female case of juvenile/adult type galactosialidosis. Clinically, she presented with short stature, coarse facies, angiokeratoma, remarkable action myoclonus, and cerebellar ataxia. The patient was diagnosed with galactosialidosis with confirmation of impaired β-galactosidase and neuraminidase function in cultured skin fibroblasts. Sanger sequencing for CTSA identified a compound heterozygous mutation consisting of NM_00308.3(CTSA):c.746 + 3A>G and c.655-1G>A. Additional analysis of her mother’s DNA sequence indicated that the former mutation originated from her mother, and therefore the latter was estimated to be from the father or was a de novo mutation. Both mutations are considered pathogenic owing to possible splicing abnormalities. One of them (c.655-1G>A) is novel because it has never been reported previously

X-ray investigation of the diffuse emission around plausible gamma-ray emitting pulsar wind nebulae in Kookaburra region

We report on the results from {\it Suzaku} X-ray observations of the radio complex region called Kookaburra, which includes two adjacent TeV $\gamma$-ray sources HESS J1418-609 and HESS J1420-607. The {\it Suzaku} observation revealed X-ray diffuse emission around a middle-aged pulsar PSR J1420-6048 and a plausible PWN Rabbit with elongated sizes of $\sigma_{\rm X}=1^{\prime}.66$ and $\sigma_{\rm X}=1^{\prime}.49$, respectively. The peaks of the diffuse X-ray emission are located within the $\gamma$-ray excess maps obtained by H.E.S.S. and the offsets from the $\gamma$-ray peaks are $2^{\prime}.8$ for PSR J1420-6048 and $4^{\prime}.5$ for Rabbit. The X-ray spectra of the two sources were well reproduced by absorbed power-law models with $\Gamma=1.7-2.3$. The spectral shapes tend to become softer according to the distance from the X-ray peaks. Assuming the one zone electron emission model as the first order approximation, the ambient magnetic field strengths of HESS J1420-607 and HESS J1418-609 can be estimated as 3 $\mu$G, and $2.5 \mu$G, respectively. The X-ray spectral and spatial properties strongly support that both TeV sources are pulsar wind nebulae, in which electrons and positrons accelerated at termination shocks of the pulsar winds are losing their energies via the synchrotron radiation and inverse Compton scattering as they are transported outward.Comment: To appear in Ap

Gravitational fermion creation during an anisotropic phase of cosmological expansion

The free Dirac equation is solved in a Bianchi Type I space-time, which represents a homogeneous but anisotropic universe, to show the creation of fermionic particles. It is found that unlike in the isotropic case, massless fermion production is possible. An estimate of the energy density of massless particles created during an early anisotropic phase of cosmological expansion is shown to cause substantial back-reaction on the gravitational field. The potential relevance to dark matter particle production, primordial magnetogenesis, and early universe cosmology is discussed briefly.Comment: Accepted for publication in Physical Review

A Suzaku Observation of the Low-Ionization Fe-Line Emission from RCW 86

The newly operational X-ray satellite Suzaku observed the southwestern quadrant of the supernova remnant (SNR) RCW 86 in February 2006 to study the nature of the 6.4 keV emission line first detected with the Advanced Satellite for Cosmology and Astronomy (ASCA). The new data confirm the existence of the line, localizing it for the first time; most of the line emission is adjacent and interior to the forward shock and not at the locus of the continuum hard emission. We also report the first detection of a 7.1 keV line that we interpret as the K-beta emission from low-ionization iron. The Fe-K line features are consistent with a non-equilibrium plasma of Fe-rich ejecta with n_{e}t <~ 10^9 cm^-3 s and kT_{e} ~ 5 keV. This combination of low n_{e}t and high kT_{e} suggests collisionless electron heating in an SNR shock. The Fe K-alpha line shows evidence for intrinsic broadening, with a width of 47 (34--59) eV (99% error region). The difference of the spatial distributions of the hard continuum above 3 keV and the Fe-K line emission support a synchrotron origin for the hard continuum.Comment: 6 pages with 6 figures. Accepted for PASJ Suzaku Special Issue (vo. 58, sp.1

Reducing variability among treatment machines using knowledge‐based planning for head and neck, pancreatic, and rectal cancer

PURPOSE: This study aimed to assess dosimetric indices of RapidPlan model-based plans for different energies (6, 8, 10, and 15 MV; 6- and 10-MV flattening filter-free), multileaf collimator (MLC) types (Millennium 120, High Definition 120, dual-layer MLC), and disease sites (head and neck, pancreatic, and rectal cancer) and compare these parameters with those of clinical plans. METHODS: RapidPlan models in the Eclipse version 15.6 were used with the data of 28, 42, and 20 patients with head and neck, pancreatic, and rectal cancer, respectively. RapidPlan models of head and neck, pancreatic, and rectal cancer were created for TrueBeam STx (High Definition 120) with 6 MV, TrueBeam STx with 10-MV flattening filter-free, and Clinac iX (Millennium 120) with 15 MV, respectively. The models were used to create volumetric-modulated arc therapy plans for a 10-patient test dataset using all energy and MLC types at all disease sites. The Holm test was used to compare multiple dosimetric indices in different treatment machines and energy types. RESULTS: The dosimetric indices for planning target volume and organs at risk in RapidPlan model-based plans were comparable to those in the clinical plan. Furthermore, no dose difference was observed among the RapidPlan models. The variability among RapidPlan models was consistent regardless of the treatment machines, MLC types, and energy. CONCLUSIONS: Dosimetric indices of RapidPlan model-based plans appear to be comparable to the ones based on clinical plans regardless of energies, MLC types, and disease sites. The results suggest that the RapidPlan model can generate treatment plans independent of the type of treatment machine

Thermal and Non-thermal X-Rays from the LMC Super Bubble 30 Dor C

We report on the discovery of thermal and non-thermal X-rays from the shells of the super bubble (SB) 30 Dor C in the Large Magellanic Cloud (LMC). The X-ray morphology is a nearly circular shell with a radius of about 40 pc, which is bright on the northern and western sides. The spectra of the shells are different from region to region. The southern shell shows clear emission lines, and is well fitted with a model of a thin-thermal plasma (kT = 0.21keV) in non-equilibrium ionization (NEI) plus a power-law component. This thermal plasma is located inside of the H alpha emission, which is the outer edge of the shell of the SB. The northern and western sides of the SB are dim in H alpha emission, but are bright in non-thermal (power-law) X-rays with a photon index of 2.1-2.9. The non-thermal X-ray shell traces the outer boundary of the radio shell. These features of thin-thermal and non-thermal X-rays are similar to those of SN 1006, a prototype of synchrotron X-ray shell, but the non-thermal component of 30 Dor C is about ten-times brighter than that of SN 1006. 30 Dor C is the first candidate of an extragalactic SB, in which energetic electrons are accelerating in the shell. The age is much older than that of SN 1006, and hence the particle acceleration time in this SB may be longer than those in normal shell-like SNRs. We found point-like sources associated with some of tight star clusters. The X-ray luminosity and spectrum are consistent with those of young clusters of massive stars. Point-like sources with non-thermal spectra are also found in the SB. These may be background objects (AGNs) or stellar remnants (neutron stars or black holes).Comment: 11 pages, 6 figures, Accepted for publication in ApJ, the paper with full resolution images in http://www-cr.scphys.kyoto-u.ac.jp/member/bamba/Paper/30DorC.pd

Advantage of Handwriting Over Typing on Learning Words: Evidence From an N400 Event-Related Potential Index

The growing implementation of digital education comes with an increased need to understand the impact of digital tools on learning. Previous behavioral studies have shown that handwriting on paper is more effective for learning than typing on a keyboard. However, the impact of writing with a digital pen on a tablet remains to be clarified. In the present study, we compared learning by handwriting with an ink pen on paper, handwriting with a digital pen on a tablet, and typing on a keyboard. Behavioral and electroencephalographic indices were measured immediately after learning with each writing tool. The moods of the subjects during the training were also assessed. The participants were divided according to their use of digital pen in their everyday lives, allowing us to take into account the effect of the familiarity with the digital pen on the learning process (familiar group vs. unfamiliar group). We performed an EEG experiment applying a repetition priming paradigm. In each trial, a learned foreign language word (prime word) and a mother tongue word (target word) were consecutively presented. The target word was either semantically identical to the prime word (repetitive condition) or different (non-repetitive condition). We assumed that a larger priming effect on N400 reflects larger learning progress. The familiar group showed a greater N400 priming effect for words learned with the digital or ink pen than those learned with the keyboard. The unfamiliar group showed the greater N400 priming effect for words learned with the ink pen compared with words learned by typing. In addition, positive mood during learning was significantly higher during handwriting than during typing, regardless of the groups. On the other hand, the behavioral indices were not influenced by the writing tool. These results suggest that the movements involved in handwriting allow a greater memorization of new words. The advantage of handwriting over typing might also be caused by a more positive mood during learning. Finally, our results show that handwriting with a digital pen and tablet can increase the ability to learn compared with keyboard typing once the individuals are accustomed to it

X-Ray Spectroscopy of SN 1006 with Suzaku

We report on observations of SN 1006 with the X-ray Imaging Spectrometers (XIS) on board Suzaku. We firmly detected K-shell emission from Fe, for the first time, and find that the Fe ionization state is quite low. The broad band spectrum extracted from the southeast of the remnant is well fitted with a model consisting of three optically thin thermal non-equilibrium ionization plasmas and a power-law component. Two of the thermal models are highly overabundant in heavy elements and, hence, are likely due to ejecta. These components have different ionization parameters: $n_et \sim 1.4\times 10^{10}$ cm$^{-3}$ s and $n_et \sim 7.7\times 10^8$ cm$^{-3}$ s and it is the later one that produces the Fe-K emission. This suggests that Fe has been heated by the reverse shock more recently than the other elements, consistent with a picture where the ejecta are stratified by composition with Fe in the interior. On the other hand, the third thermal component is assumed to be solar abundance, and we associate it with emission from the interstellar medium (ISM). The electron temperature and ionization parameter are $kT_e \sim$0.5 keV and $n_et \sim 5.8\times 10^9$ cm$^{-3}$ s. The electron temperature is lower than that expected from the shock velocity which suggests a lack of collisionless electron heating at the forward shock. The extremely low ionization parameter and extreme non-equilibrium state are due to the low density of the ambient medium.Comment: 12 pages, 9 figures (14 figure files), accepted for publication in PAS