2000-2001年の太平洋西部海域におけるプラスチック微小片の分布

Sampling was conducted at 31 sites in the western Pacific Ocean from 2000 to 2001 with the aim of collecting plastic fragments with a neuston net (mesh size: 1.00 mm × 1.64 mm). Small plastic fragments including microplastics (small fragments in the size range of 1.1–41.8 mm) were collected at multiple survey sites. Waters with high densities of small fragments were observed between 20°N and 30°N to the south of Japan and between 20°S and 30°S to the northeast of New Zealand (maxima of 6.63 × 102 and 2.04 × 102 pieces/ha, respectively). These waters are located to the west of the Ekman convergence zones related to trade winds in the subtropical gyres of the North and South Pacific Oceans. Nearly no small plastics were observed in the tropical circulation of the western Pacific Ocean.2000年から2001年にかけて太平洋西部海域の31地点でニューストンネット（目合1.00mm×1.64mm）によるプラスチック微小片の採集を行った。マイクロプラスチック(5mm以下)を含むプラスチック微小片は，日本の南の北緯20—30度の海域とニュージーランド北東の南緯20—30度の海域で高密度に採集され（各々最高で6.63×102と2.04×102個/ha），これらの海域は北太平洋と南太平洋における亜熱帯循環内の漂流物収束帯の西端に位置する。赤道付近の熱帯循環内の採集点ではほとんど採集されなかった

Twenty barrel in situ pipe gun type solid hydrogen pellet injector for the Large Helical Device

A 20 barrel solid hydrogen pellet injector, which is able to inject 20 cylindrical pellets with a diameter and length of between 3.0 and 3.8 mm at the velocity of 1200 m/s, has been developed for the purpose of direct core fueling in LHD (Large Helical Device). The in situ pipe gun concept with the use of compact cryo-coolers enables stable operation as a fundamental facility in plasma experiments. The combination of the two types of pellet injection timing control modes, i.e., pre-programing mode and real-time control mode, allows the build-up and sustainment of high density plasma around the density limit. The pellet injector has demonstrated stable operation characteristics during the past three years of LHD experiments

Evolution of the primate glutamate taste sensor from a nucleotide sensor

霊長類におけるグルタミン酸の旨味の起源 --体の大きな霊長類は旨味感覚で葉の苦さを克服--. 京都大学プレスリリース. 2021-08-30.Taste perception plays an essential role in food selection. Umami (savory) tastes are sensed by a taste receptor complex, T1R1/T1R3, that detects proteinogenic amino acids. High sensitivity to l-glutamate (l-Glu) is a characteristic of human T1R1/T1R3, but the T1R1/T1R3 of other vertebrates does not consistently show this l-Glu response. Here, we demonstrate that the l-Glu sensitivity of T1R1/T1R3 is a derived state that has evolved repeatedly in large primates that rely on leaves as protein sources, after their divergence from insectivorous ancestors. Receptor expression experiments show that common amino acid substitutions at ligand binding sites that render T1R1/T1R3 sensitive to l-Glu occur independently at least three times in primate evolution. Meanwhile T1R1/T1R3 senses 5′-ribonucleotides as opposed to l-Glu in several mammalian species, including insectivorous primates. Our chemical analysis reveal that l-Glu is one of the major free amino acids in primate diets and that insects, but not leaves, contain large amounts of free 5′-ribonucleotides. Altering the ligand-binding preference of T1R1/T1R3 from 5′-ribonucleotides to l-Glu might promote leaf consumption, overcoming bitter and aversive tastes. Altogether, our results provide insight into the foraging ecology of a diverse mammalian radiation and help reveal how evolution of sensory genes facilitates invasion of new ecological niches

A Comparative Study on Transformer vs RNN in Speech Applications

Sequence-to-sequence models have been widely used in end-to-end speech processing, for example, automatic speech recognition (ASR), speech translation (ST), and text-to-speech (TTS). This paper focuses on an emergent sequence-to-sequence model called Transformer, which achieves state-of-the-art performance in neural machine translation and other natural language processing applications. We undertook intensive studies in which we experimentally compared and analyzed Transformer and conventional recurrent neural networks (RNN) in a total of 15 ASR, one multilingual ASR, one ST, and two TTS benchmarks. Our experiments revealed various training tips and significant performance benefits obtained with Transformer for each task including the surprising superiority of Transformer in 13/15 ASR benchmarks in comparison with RNN. We are preparing to release Kaldi-style reproducible recipes using open source and publicly available datasets for all the ASR, ST, and TTS tasks for the community to succeed our exciting outcomes.Comment: Accepted at ASRU 201

Long-Term Voyages and Bone Mass Among Seamen

東京水産大学海洋生産学専攻東京水産大学練習船海鷹丸東京水産大学練習船神鷹丸東京水産大学練習船海鷹丸東京水産大学練習船海鷹丸東京水産大学練習船神鷹丸東京水産大学練習船神鷹丸東京水産大学練習船海鷹丸東京水産大学練習船神鷹丸東京水産大学海洋生産学科東京水産大学海洋生産学

The Quiescent Intracluster Medium in the Core of the Perseus Cluster

Clusters of galaxies are the most massive gravitationally-bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and a host of astrophysical processes. Knowledge of the dynamics of the pervasive hot gas, which dominates in mass over stars in a cluster, is a crucial missing ingredient. It can enable new insights into mechanical energy injection by the central supermassive black hole and the use of hydrostatic equilibrium for the determination of cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50 million K diffuse hot plasma filling its gravitational potential well. The Active Galactic Nucleus of the central galaxy NGC1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These likely induce motions in the intracluster medium and heat the inner gas preventing runaway radiative cooling; a process known as Active Galactic Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus cluster core, which reveal a remarkably quiescent atmosphere where the gas has a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s is found across the 60 kpc image of the cluster core. Turbulent pressure support in the gas is 4% or less of the thermodynamic pressure, with large scale shear at most doubling that estimate. We infer that total cluster masses determined from hydrostatic equilibrium in the central regions need little correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July