2006 Fragmentation of Comet 73P/Schwassmann-Wachmann 3B Observed with Subaru/Suprime-Cam

We analyzed the Subaru/Suprime-Cam images of 73P/Schwassmann-Wachmann 3B and detected no fewer than 154 mini-comets. We applied synchrone-syndyne analysis, modified for rocket effect analysis, to the mini-fragment spatial distribution. We found that most of these mini-comets were ejected from fragment B by an outburst occurring around 1 April 2006. The ratio of the rocket force to solar gravity was 7 to 23 times larger than that exerted on fragment B. No significant color variation was found. We examined the surface brightness profiles of all detected fragments and estimated the sizes of 154 fragments. We found that the radius of these mini-fragments was in the 5- to 108-m range (equivalent size of Tunguska impactor). The power-law index of the differential size distribution was q = -3.34 +/- 0.05. Based on this size distribution, we found that about 1-10% of the mass of fragment B was lost in the April 2006 outbursts. Modeling the cometary fragment dynamics revealed that it is likely that mini-fragments smaller than ~10-20 m could be depleted in water ice and become inactive, implying that decameter-sized comet fragments could survive against melting and remain as near-Earth objects. We attempted to detect the dust trail, which was clearly found in infrared wavelengths by Spitzer. No brightness enhancement brighter than 30.0 mag arcsec^-2 (3sigma) was detected in the orbit of fragment B.Comment: Total pages: 46 Figures: 12 Tables: 1 To appear ICARU

Detection of an H-alpha Emission Line on a Quasar, RX J1759.4+6638, at z=4.3 with AKARI

We report the detection of an H-alpha emission line in the low resolution spectrum of a quasar, RX J1759.4+6638, at a redshift of 4.3 with the InfraRed Camera (IRC) onboard the AKARI. This is the first spectroscopic detection of an H-alpha emission line in a quasar beyond z=4. The overall spectral energy distribution (SED) of RX J1759.4+6638 in the near- and mid-infrared wavelengths agrees with a median SED of the nearby quasars and the flux ratio of F(Ly-alpha)/F(H-alpha) is consistent with those of previous reports for lower-redshift quasars.Comment: 9pages, 3 figures, Publications of the Astronomical Society of Japan, in pres

Fermi level tuning of Ag-doped Bi2Se3 topological insulator

The temperature dependence of the resistivity (rho) of Ag-doped Bi2Se3 (AgxBi2-xSe3) shows insulating behavior above 35 K, but below 35 K, rho suddenly decreases with decreasing temperature, in contrast to the metallic behavior for non-doped Bi2Se3 at 1.5-300 K. This significant change in transport properties from metallic behavior clearly shows that the Ag doping of Bi2Se3 can effectively tune the Fermi level downward. The Hall effect measurement shows that carrier is still electron in AgxBi2-xSe3 and the electron density changes with temperature to reasonably explain the transport properties. Furthermore, the positive gating of AgxBi2-xSe3 provides metallic behavior that is similar to that of non-doped Bi2Se3, indicating a successful upward tuning of the Fermi level

AKARI infrared imaging of reflection nebulae IC4954 and IC4955

We present the observations of the reflection nebulae IC4954 and IC4955 region with the Infrared Camera (IRC) and the Far-Infrared Surveyor (FIS) on board the infrared astronomical satellite AKARI during its performance verification phase. We obtained 7 band images from 7 to 160um with higher spatial resolution and higher sensitivities than previous observations. The mid-infrared color of the S9W (9um) and L18W (18um) bands shows a systematic variation around the exciting sources. The spatial variation in the mid-infrared color suggests that the star-formation in IC4954/4955 is progressing from south-west to north-east. The FIS data also clearly resolve two nebulae for the first time in the far-infrared. The FIS 4-band data from 65um to 160um allow us to correctly estimate the total infrared luminosity from the region, which is about one sixth of the energy emitted from the existing stellar sources. Five candidates for young stellar objects have been detected as point sources for the first time in the 11um image. They are located in the red S9W to L18W color regions, suggesting that current star-formation has been triggered by previous star-formation activities. A wide area map of the size of about 1 x 1 (deg^2) around the IC4954/4955 region was created from the AKARI mid-infrared all-sky survey data. Together with the HI 21cm data, it suggests a large hollow structure of a degree scale, on whose edge the IC4954/4955 region has been created, indicating star formation over three generations in largely different spatial scales.Comment: 23 pages, 7 figures, accepted for publication in PASJ AKARI special issu

Nature of Infrared Sources in 11 micron Selected Sample from Early Data of the AKARI North Ecliptic Pole Deep Survey

We present the properties of 11 $\mu$m selected sources detected in the early data of the North Ecliptic Pole Deep (NEP-Deep) Survey of AKARI. The data set covers 6 wavelength bands from 2.5 to 11 $\mu$m, with the exposure time of 10 ~ 20 minutes. This field lies within the CFHT survey with four filter bands ($g', r', i',z'), enabling us to establish nearly continuous spectral energy distributions (SEDs) for wavelengths ranging from 0.4 to 11$\mu$m. The main sample studied here consists of 71 sources whose 11$\mu$m AB magnitudes are equal to or brighter than 18.5 (251$\mu$Jy), which is complete to more than 90$\mu$m band has an advantage of sampling star forming galaxies with low to medium redshifts since the prominent PAH feature shifts into this band. As expected, we find that the majority (~68$\mu$m bright sources are star forming galaxies at 0.2 < z < 0.7 with$L_{IR} ~ 10^{10}$--$10^{12} L_{\odot}$ based on the detailed modelling of SEDs. We also find four AGNs lying at various redshifts in the main sample. In addition, we discuss a few sources which have non-typical SEDs of the main sample, including a brown dwarf candidate, a steep power-law source, flat spectrum object, and an early-type galaxy at moderate redshift.Comment: 22 pages, 10 figure

B cell-derived GABA elicits IL-10⁺ macrophages to limit anti-tumour immunity

GABAを標的とする抗腫瘍免疫機構 --代謝産物を介した免疫細胞間制御の一端を解明--. 京都大学プレスリリース. 2021-11-10.Small, soluble metabolites not only are essential intermediates in intracellular biochemical processes, but can also influence neighbouring cells when released into the extracellular milieu1-3. Here we identify the metabolite and neurotransmitter GABA as a candidate signalling molecule synthesized and secreted by activated B cells and plasma cells. We show that B cell-derived GABA promotes monocyte differentiation into anti-inflammatory macrophages that secrete interleukin-10 and inhibit CD8⁺ T cell killer function. In mice, B cell deficiency or B cell-specific inactivation of the GABA-generating enzyme GAD67 enhances anti-tumour responses. Our study reveals that, in addition to cytokines and membrane proteins, small metabolites derived from B-lineage cells have immunoregulatory functions, which may be pharmaceutical targets allowing fine-tuning of immune responses

シンセツ カンゴ ガクブ ニ オケル カンゴ ジッセン ノウリョク イクセイ ノ タメ ノ カンゴ ギジュツ コウモク ノ ケントウ

背景 高齢化社会や医療の高度化の到来から, 看護学生の看護実践能力の強化の必要性が重要課題となっている. 目的 新設看護学部において看護実践能力が高い学生を育成するために必要と考えられる看護技術項目を明らかにすることを目的とした. 方法 各看護学領域代表者で技術項目検討委員会をもち, 本学部の教育理念に従って, 既存文献を参考にしながら, 項目を追加修正し, 各看護学領域が講義・演習・実習のどこで学習するかを確認した. 結果 学生の看護実践能力を育成する為の看護技術項目は19項目の大項目, 131の中項目, 160の小項目と整理し, 看護技術項目のシートを作成した. 結論 作成したシートは, 各看護学領域で学習する内容を講義の教材として活用し, 学生・教員・実習の指導者の3者間で, 個々の学生の看護技術の習得に有効であると考える. またそれは, 学生の看護実践能力の強化へと期待できる.Background With the aging of society and the advances in medical care technologies, it is increasingly important and necessary for nursing students to be able to use their nursing knowledge and skills in a practical setting. Educational institutions are therefore urged to provide the students with such training.Purpose The purpose of this paper is to clarify what skills are actually necessary and useful for students to become effective in their practice as nurses, and what training should be given at the new nursing department in order to enhance the practical nursing skills of students.Methods First, scholars and representatives of nursing-related fields formed a committee where skills required for achieving the purpose stated above were redefined in accordance with the university\u27s educational objectives. In revising the existing skills items, published information was also used as a reference. How each of the skills is learned, either in lectures, classroom training, or practical training, was confirmed by the committee.Results The nursing skills identified by the committee were classified into 19 skills of major importance, 131 skills of medium importance and 160 skills of less importance. The committee summarized them as a list of nursing skills.Conclusion The list can be used as teaching materials in the class, and can be used not only by teachers and advisors in the training but also by students. Students would refer to the list when learning nursing skills. Such use of the list may reinforce students\u27 ability to apply the obtained skills in their nursing performance