サケ科魚類の寄生虫，マスウキブクロセンチュウSalvelinema salmonicolaの新産地

山形県最上川水系小国川の支流である大横川で採集したヤマメOncorhynchus masou masou (Brevoort, 1856)の鰾と，島根県益田川で採集したヤマメの鰾から，マスウキブクロセンチュウ（鱒鰾線虫）Salvelinema salmonicola (Ishii, 1916)を得た。本線虫は両県から初記録である。Specimens of the cystidicolid nematode Salvelinema salmonicola (Ishii, 1916) were collected from the swim bladder of river-resident masu salmon, Oncorhynchus masou masou (Brevoort, 1856), in Yamagata and Shimane prefectures, Honshu, Japan. This nematode is reported herein for the first time from these two prefectures in Japan

VERA monitoring of the radio jet 3C 84 during 2007--2013: detection of non-linear motion

We present a kinematic study of the subparsec-scale radio jet of the radio galaxy 3C 84/NGC 1275 with the VLBI Exploration of Radio Astrometry (VERA) array at 22 GHz for 80 epochs from 2007 October to 2013 December. The averaged radial velocity of the bright component "C3" with reference to the radio core is found to be $0.27 pm 0.02c$ between 2007 October and 2013 December. This constant velocity of C3 is naturally explained by the advancing motion of the head of the mini-radio lobe. We also find a non-linear component in the motion of C3 with respect to the radio core. We briefly discuss possible origins of this non-linear motion.Comment: 11 pages, 7 figures, 8 tables (table 1 - 5 are supplementaries), accepted for publication on PAS

Large, Negative Magnetoresistance in an Oleic Acid-Coated Fe3O4 Nanocrystal Self-Assembled Film

An oleic acid-coated Fe3O4 nanocrystal self-assembled film was fabricated via drop casting of colloidal particles on a SiO2/Si substrate. The film exhibited bifurcation of the zero-field-cooled and field-cooled magnetizations around 250 K. The nonlinear current-voltage (I–V) characteristics between the source and drain electrodes in both zero and non-zero magnetic fields (H) were observed above and below the bifurcation temperature. A large negative magnetoresistance (MR ≈ −60%) was achieved at 200 K and H = 1 T. Even at 295 K and 0.2 T, the negative MR (≈ −50%) persisted. A Fowler–Nordheim plot and power-law scaling of the I–V characteristics revealed that the current flows through two-dimensional (2D) percolated electron tunneling paths. The enlargement of MR can be attributed to spin-dependent electron tunneling between magnetically coupled Fe3O4 nanocrystals self-assembled in 2D ordered arrays

A Public-key Encryption Scheme Based on Non-linear Indeterminate Equations (Giophantus)

In this paper, we propose a post-quantum public-key encryption scheme whose security depends on a problem arising from a multivariate non-linear indeterminate equation. The security of lattice cryptosystems, which are considered to be the most promising candidate for a post-quantum cryptosystem, is based on the shortest vector problem or the closest vector problem in the discrete linear solution spaces of simultaneous equations. However, several improved attacks for the underlying problems have recently been developed by using approximation methods, which result in requiring longer key sizes. As a scheme to avoid such attacks, we propose a public-key encryption scheme based on the smallest solution problem in the non-linear solution spaces of multivariate indeterminate equations that was developed from the algebraic surface cryptosystem. Since no efficient algorithm to find such a smallest solution is currently known, we introduce a new computational assumption under which proposed scheme is proven to be secure in the sense of IND-CPA. Then, we perform computational experiments based on known attack methods and evaluate that the key size of our scheme under the linear condition. This paper is a revised version of SAC2017

Spatio-temporal distribution of environmental DNA derived from Japanese sea nettle jellyfish Chrysaora pacifica in Omura Bay, Kyushu, Japan

We surveyed the spatial and temporal distribution of Japanese sea nettle jellyfish Chrysaora pacifica in Omura Bay, Japan, using an environmental DNA (eDNA) method. In 2018, the C. pacifica eDNA concentration increased from March?May at all depths. The seasonal pattern of C. pacifica eDNA was consistent with previous reports based on visual observations along the Japanese coast. Thus, the eDNA method might have advantages to follow the seasonal pattern of C. pacifica while being less time-consuming and less laborious compared with traditional methods. The eDNA concentrations tended to reach a maximum near and/or below the pycnocline throughout this study. Therefore, the vertical distribution of C. pacifica medusae may have been restricted by strong pycnocline formation in July and August 2018. However, even with a weak pycnocline, which C. pacifica should be able to swim across, the apparent distribution of C. pacifica eDNA seems to be restricted by the pycnocline. Therefore, the eDNA method cannot, currently, accurately assess the absolute vertical distribution pattern of C. pacifica, especially when a pycnocline is formed

Revealing the Hidden Spin-Polarized Bands in a Superconducting Tl Bilayer Crystal

The interplay of spin-orbit coupling and crystal symmetry can generate spin-polarized bands in materials only a few atomic layers thick, potentially leading to unprecedented physical properties. In the case of bilayer materials with global inversion symmetry, locally broken inversion symmetry can generate degenerate spin-polarized bands, in which the spins in each layer are oppositely polarized. Here, we demonstrate that the hidden spins in a Tl bilayer crystal are revealed by growing it on Ag(111) of sizable lattice mismatch, together with the appearance of a remarkable phenomenon unique to centrosymmetric hidden-spin bilayer crystals: a novel band splitting in both spin and space. The key to success in observing this novel splitting is that the interaction at the interface has just the right strength: it does not destroy the original wave functions of the Tl bilayer but is strong enough to induce an energy separation

Alteration of FHR pattern and cerebral metabolic rate of glucose of the fetus measured by positron emission tomography during progress of acidemia. The significance of overshoot acceleration in FHR

Peer Reviewe

Precessing jet nozzle connecting to a spinning black hole in M87

The nearby radio galaxy M87 offers a unique opportunity to explore the connections between the central supermassive black hole and relativistic jets. Previous studies of the inner region of M87 revealed a wide opening angle for the jet originating near the black hole. The Event Horizon Telescope resolved the central radio source and found an asymmetric ring structure consistent with expectations from General Relativity. With a baseline of 17 years of observations, there was a shift in the jet's transverse position, possibly arising from an eight to ten-year quasi-periodicity. However, the origin of this sideways shift remains unclear. Here we report an analysis of radio observations over 22 years that suggests a period of about 11 years in the position angle variation of the jet. We infer that we are seeing a spinning black hole that induces the Lense-Thirring precession of a misaligned accretion disk. Similar jet precession may commonly occur in other active galactic nuclei but has been challenging to detect owing to the small magnitude and long period of the variation.Comment: 41 pages, 7 figures, 7 table

妊娠中期の妊婦に発症し，体外式腹部超音波検査にて術前診断しえた虫垂憩室炎の一例

虫垂憩室炎は比較的稀な疾患であり，急性虫垂炎と比べ，穿孔率が高いがその術前診断は難しい．体外式腹部超音波検査で術前に診断した虫垂憩室炎の1症例を経験したので，文献的考察を加えて報告する．症例は24歳，妊娠25週５日の女性．腹痛を主訴に近医を受診したところ，急性虫垂炎の疑いで当院へ紹介受診となった．体外式腹部超音波検査で，虫垂憩室炎と診断し，緊急手術となった．切除標本の病理学的検査により，虫垂憩室炎と確定診断された．Preoperative diagnosis of appendiceal diverticulitis is considered difficult. Differentiation between acute appendicitis and appendiceal diverticulitis is clinically important because the latter condition has a higher risk of perforation. We report a case of a 24-year-old pregnant (25 weeks and 5 days of gestation) woman who complained of right lower quadrant pain. After visiting a primary care doctor, she was referred to our hospital with suspected acute appendicitis. Ultrasound showed that the appendix was swollen and there were several low echoic lesions in the vicinity of the point of the appendix. Blood flow was shaped in an arc around the low echoic lesion as shown by Doppler color flow imaging. We observed thickness and hyperechoic change, which was affected by inflammation in the mesoappendix. She underwent appendectomy and a pathological examination of the resected specimen confirmed the diagnosis of appendiceal diverticulitis