著者
Kiwamu NISHIDA
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.93, no.7, pp.423-448, 2017-08-02 (Released:2017-08-02)
参考文献数
183
被引用文献数
60

The ambient seismic wave field, also known as ambient noise, is excited by oceanic gravity waves primarily. This can be categorized as seismic hum (1–20 mHz), primary microseisms (0.02–0.1 Hz), and secondary microseisms (0.1–1 Hz). Below 20 mHz, pressure fluctuations of ocean infragravity waves reach the abyssal floor. Topographic coupling between seismic waves and ocean infragravity waves at the abyssal floor can explain the observed shear traction sources. Below 5 mHz, atmospheric disturbances may also contribute to this excitation. Excitation of primary microseisms can be attributed to topographic coupling between ocean swell and seismic waves on subtle undulation of continental shelves. Excitation of secondary microseisms can be attributed to non-linear forcing by standing ocean swell at the sea surface in both pelagic and coastal regions. Recent developments in source location based on body-wave microseisms enable us to estimate forcing quantitatively. For a comprehensive understanding, we must consider the solid Earth, the ocean, and the atmosphere as a coupled system.
著者
Masaharu TSUBOKURA Yuko NABESHIMA Michio MURAKAMI Tsuyoshi NEMOTO Toshiyuki KAMBE Saori NONAKA Yuki SHIMADA Yurie KOBASHI Akihiko OZAKI Tomoyoshi OIKAWA
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.96, no.2, pp.70-78, 2020-02-10 (Released:2020-02-10)
参考文献数
31
被引用文献数
12

Responding to the radiation-related concerns of parents/guardians with infants/small children is an important public health issue for regional recovery after radioactive contamination. This study summarizes the results of a systematic internal contamination screening of infants/small children, aged 0–6 years, using BABYSCAN and individual counselling sessions with physicians about radiation concerns from 2014 to 2018 in Minamisoma City. Of 3,114 participants, no one was found to have internal contamination with radioactive caesium with a detection limit of 50 Bq/body. The questionnaire survey showed a decreasing trend of concerns about food contamination and playing outside as possible causes of internal contamination over time. Because people’s concerns were diverse in counselling sessions, individual responses are required. This study showed that examinations using BABYSCAN provide an opportunity for direct dialogue between the parents/guardians of infants/small children and experts. This can be considered a model case for risk communication conducted by the local government after a radioactive contamination incident.
著者
Kazuhiro SUZUKI Akiko IKEDA Kaori ADACHI Daniel DUNKLEY Etsuko NIU Takenori KATO Shinobu MORI Noriyuki FUJII
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.78, no.5, pp.111-116, 2002 (Released:2006-10-17)
参考文献数
15
被引用文献数
1

The Kamimura River, an upper tributary of the Yahagi River, flows through steep valleys in the mountainous Kamiyahagi area of Gifu Prefecture. The Tokai Gou flood of September 11-12, 2000 destroyed embankments along the river, and exposed sedimentary layers at Umi that are typical of a lacustrine depositional setting. This confirms the existence of a paleo-lake from which the name Umi originated. The lake was formed as the result of a huge landslide that dammed up the Kamimura River. To determine when the landslide occurred, radiocarbon (14C) ages of trees buried in lacustrine sediments were determined using accelerator mass spectrometry (AMS). The 14C ages are 300±25, 340±25, 345±25 and 380±25 BP for the outermost rings of tree trunks, which include bark, and a single age of 620±25 BP. Calibrated ages of (1637), (1520, 1590, 1624), (1517, 1597, 1619) and (1482) cal AD within a range of 1455-1643 cal AD are consistent with a landslide triggered by the Tensho Earthquake of January 18, 1586, which had an estimated magnitude of 8.2-8.3 and an epicenter in Ise Bay.
著者
Koji OKABAYASHI Makoto ASASHIMA
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.82, no.7, pp.197-207, 2006 (Released:2006-11-18)
参考文献数
78
被引用文献数
1 1

Mesoderm induction as a result of the interaction between endoderm and ectoderm is one of the most crucial events in vertebrate development. We identified activin as a strong mesoderm-inducing factor in an animal cap assay, an in vitro assay system using amphibian pluripotential cell mass. Activin induces mesodermal tisswes including most dorsal mesodermal tissue, notochord (which has important roles in neural induction, somite segmentation, and endodermal organogenesis), and its effects are concentration-dependent. Animal cap cells treated with high concentrations of activin differentiate into anterior endoderm, which can act as an organizer, or center of body patterning. We have established an in vitro induction system for 22 different organs and tissues using animal cap cells, and have isolated many organ-specific genes. With these useful methods, and analysis of newly isolated tissue- and organ-specific genes, the molecular biological “road map” for organogenesis is being established. (Communicated by Masatoshi TAKEICHI, M.J.A.)
著者
Kazushige OBARA
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.96, no.7, pp.297-315, 2020-07-31 (Released:2020-08-12)
参考文献数
98
被引用文献数
14

Slow earthquakes are a recently discovered phenomenon that mainly occur updip and downdip of the seismogenic zones of great earthquakes along the subducting plate interface. The spatiotemporal activity of various slow earthquakes occurring in the Nankai subduction zone is characterized by along-strike heterogeneity and along-dip systematic changes. Various slow earthquakes are horizontally distributed at their own depths and along-strike segments can be observed with respect to this distribution downdip of the locked zone; however, slow and great earthquakes occur in the same depth range near the Nankai Trough and Japan Trench axes. The frequently observed spatiotemporal interactions between different slow earthquakes can be attributed to their sensitivity and the stress transfer of the surrounding areas. This stress transfer is expected to extend to the adjacent sections in the seismogenic zone. Therefore, precise monitoring of slow earthquakes is important for future evaluations of great earthquakes, which requires the long-term maintenance and continuous improvement of the high-quality observation networks.
著者
Masuo SUZUKI
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.95, no.7, pp.419-429, 2019-07-31 (Released:2019-08-09)
参考文献数
16
被引用文献数
1

Reversible dynamics is well-known to obey variational principles based on the action being the time integral of a Lagrangian with time-reversal symmetry. The purpose of the present paper is to find dissipative Lagrangians giving variational principles in dissipative dynamics with broken time-reversal symmetry. Conceptually the present theory insists on new Least Dissipation & Work Principles (LDWP) based on variational integrals weighted in time, in order to unify variational principles of physics including irreversible processes on many-body systems. This is also closely related to the present author’s theory of entropy production in Kubo’s scheme of transport phenomena and all nonlinear responses beyond. Through these investigations, we can understand the meaning (as a variational integral) of the action of reversible dynamics.
著者
Hiromasa FUNATO
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.96, no.1, pp.10-31, 2020-01-10 (Released:2020-01-10)
参考文献数
248
被引用文献数
6

Forward genetics is a powerful approach to understand the molecular basis of animal behaviors. Fruit flies were the first animal to which this genetic approach was applied systematically and have provided major discoveries on behaviors including sexual, learning, circadian, and sleep-like behaviors. The development of different classes of model organism such as nematodes, zebrafish, and mice has enabled genetic research to be conducted using more-suitable organisms. The unprecedented success of forward genetic approaches was the identification of the transcription–translation negative feedback loop composed of clock genes as a fundamental and conserved mechanism of circadian rhythm. This approach has now expanded to sleep/wakefulness in mice. A conventional strategy such as dominant and recessive screenings can be modified with advances in DNA sequencing and genome editing technologies.
著者
Hideo MATSUMOTO
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.85, no.2, pp.69-82, 2009-02-28 (Released:2009-02-12)
参考文献数
34
被引用文献数
6 7

This review addresses the distribution of genetic markers of immunoglobulin G (Gm) among 130 Mongoloid populations in the world. These markers allowed the populations to be clearly divided into 2 groups, the northern and southern groups. The northern group is characterized by high frequencies of 2 marker genes, ag and ab3st, and an extremely low frequency of the marker gene afb1b3; and the southern group, in contrast, is indicated by a remarkably high frequency of afb1b3 and low frequencies of ag and ab3st. Based on the geographical distribution of the markers and gene flow of Gm ag and ab3st (northern Mongoloid marker genes) from northeast Asia to the Japanese archipelago, the Japanese population belongs basically to the northern Mongoloid group and is thus suggested to have originated in northeast Asia, most likely in the Baikal area of Siberia.(Communicated by Osamu HAYAISHI, M.J.A.)
著者
Daniel J. CAPON Naoki KANEKO Takayuki YOSHIMORI Takashi SHIMADA Florian M. WURM Peter K. HWANG Xiaohe TONG Staci A. ADAMS Graham SIMMONS Taka-Aki SATO Koichi TANAKA
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.87, no.9, pp.603-616, 2011-11-11 (Released:2011-11-11)
参考文献数
27
被引用文献数
7 7

There is a significant need for antibodies that can bind targets with greater affinity. Here we describe a novel strategy employing chemical semisynthesis to produce symmetroadhesins: antibody-like molecules having nonprotein hinge regions that are more flexible and extendible and are capable of two-handed binding. Native chemical ligation was carried out under mild, non-denaturing conditions to join a ligand binding domain (Aβ peptide) to an IgG1 Fc dimer via discrete oxyethylene oligomers of various lengths. Two-handed Aβ–Fc fusion proteins were obtained in quantitative yield and shown by surface plasmon resonance to bind an anti-Aβ antibody with a KD at least two orders of magnitude greater than the cognate Aβ peptide. MALDI-TOF MS analysis confirmed the protein/nonprotein/protein structure of the two-handed molecules, demonstrating its power to characterize complex protein-nonprotein hybrids by virtue of desorption/ionization mediated by peptide sequences contained therein. We anticipate many applications for symmetroadhesins that combine the target specificity of antibodies with the novel physical, chemical and biological properties of nonprotein hinges.(Contributed by Koichi TANAKA, M.J.A.)
著者
Satoshi IDE
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.90, no.8, pp.259-277, 2014-10-10 (Released:2014-10-11)
参考文献数
122
被引用文献数
18 25

Earthquake sources represent dynamic rupture within rocky materials at depth and often can be modeled as propagating shear slip controlled by friction laws. These laws provide boundary conditions on fault planes embedded in elastic media. Recent developments in observation networks, laboratory experiments, and methods of data analysis have expanded our knowledge of the physics of earthquakes. Newly discovered slow earthquakes are qualitatively different phenomena from ordinary fast earthquakes and provide independent information on slow deformation at depth. Many numerical simulations have been carried out to model both fast and slow earthquakes, but problems remain, especially with scaling laws. Some mechanisms are required to explain the power-law nature of earthquake rupture and the lack of characteristic length. Conceptual models that include a hierarchical structure over a wide range of scales would be helpful for characterizing diverse behavior in different seismic regions and for improving probabilistic forecasts of earthquakes.
著者
Kumi YOSHIDA Naoko MIKI Kazumi MOMONOI Miki KAWACHI Kiyoshi KATOU Yoshiji OKAZAKI Nobuyuki UOZUMI Masayoshi MAESHIMA Tadao KONDO
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.85, no.6, pp.187-197, 2009 (Released:2009-06-12)
参考文献数
42
被引用文献数
27 42

Petal color change in morning glory Ipomoea tricolor cv. Heavenly Blue, from red to blue, during the flower-opening period is due to an unusual increase in vacuolar pH (pHv) from 6.6 to 7.7 in colored epidermal cells. We clarified that this pHv increase is involved in tonoplast-localized Na+/H+ exchanger (NHX). However, the mechanism of pHv increase and the physiological role of NHX1 in petal cells have remained obscure. In this study, synchrony of petal-color change from red to blue, pHv increase, K+ accumulation, and cell expansion growth during flower-opening period were examined with special reference to ItNHX1. We concluded that ItNHX1 exchanges K+, but not Na+, with H+ to accumulate an ionic osmoticum in the vacuole, which is then followed by cell expansion growth. This function may lead to full opening of petals with a characteristic blue color.(Communicated by Ryoji NOYORI, M.J.A.)
著者
Kanetada NAGAMINE Hiroyuki K. M. TANAKA Satoshi N. NAKAMURA Katsuhiko ISHIDA Misao HASHIMOTO Akihiko SHINOTAKE Masaaki NAITO Asao HATANAKA
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.81, no.7, pp.257-260, 2005 (Released:2005-11-07)
参考文献数
4
被引用文献数
15 30

By using the detection system of the near-horizontal cosmic-ray radiography originally developed for probing inner structure of volcanic mountains, a measurement was conducted to probe the inner structure and its time-dependent change of the blast furnace for iron-making. Precise determination (±5 cm) of the thickness of brick used for both base-plate and side-wall was made in 45 days; a crucial information to predict a life-time of the furnace. Also, the local density of iron-rich part was determined in ±0.2 g/cm2 in 45 days; static structure as well as time-dependent behavior can be monitored for the iron-rich part of the furnace during operation. (Communicated by Kazuhiko NISHIJIMA, M.J.A.)
著者
Naohiko OHKOUCHI
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.99, no.5, pp.131-154, 2023-05-11 (Released:2023-05-11)
参考文献数
168
被引用文献数
5

Food web research is rapidly expanding through study of natural fractional abundance of 15N in individual amino acids. This paper overviews the principles of this isotope approach, and from my perspective, reanalyzes applications, and further extends the discussion. It applies kinetic isotope effects that enriches 15N in certain amino acids associated with the metabolic processes, which was clearly demonstrated by observations of both natural ecosystem and laboratory experiments. In trophic processes ‘trophic amino acids’ such as glutamic acid that significantly enrich 15N, whereas ‘source amino acids’ such as phenylalanine and methionine show little 15N enrichment. Through various applications conducted over the years, the principles of the method have shown to operate well and disentangle complex food webs and relevant problems. Applications include food chain length estimate, nitrogen resource assessment, tracking fish migration, and reconstruction of paleodiet. With this approach, considerations of a wide range of classical issues have been reinvigorated, while in the same time, new challenging frontiers are emerging.
著者
Masato ISHIGURO Kurazo CHIBA Seiichi SAKAMOTO
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.98, no.8, pp.439-469, 2022-10-11 (Released:2022-10-11)
参考文献数
100

The establishment of the Nobeyama Radio Observatory (NRO) in 1982 was an important event that greatly influenced the subsequent development of Japanese astronomy. The 45 m radio telescope and the Nobeyama Millimeter Array (NMA) pushed Japanese radio astronomy to the forefront of the world. As a plan beyond the Nobeyama telescopes, the Japanese radio astronomy community considered a large array to achieve unprecedented resolution at millimeter and submillimeter wavelengths under the project name of the Large Millimeter and Submillimeter Array (LMSA). After long and patient discussions and negotiations with the United States and Europe, the LMSA plan eventually led to the ALMA (Atacama Large Millimeter/submillimeter Array) as an international joint project, and the ALMA was inaugurated in 2013. This paper reviews the process from the establishment of the NRO to the realization of the ALMA, including planning of the LMSA, international negotiations, site survey, instrumental developments, and initial science results.
著者
Minoru TAKEO Yosuke AOKI Takao KOYAMA
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.98, no.8, pp.416-438, 2022-10-11 (Released:2022-10-11)
参考文献数
61
被引用文献数
1

Modern observation systems composed of seismic, geodetic, other geophysical, and geochemical networks developed in and around volcanic areas provide a mass of knowledge about volcanic activities. This paper summarizes the magma pathway and recent volcanic activity of the Asama volcano. The seismic velocity structure beneath the Asama volcano was investigated via seismic ambient noise tomography and active source seismic tomography. The magma pathway in the upper crust beneath the Asama volcano was synthesized by combining the velocity structure with a hypocenter distribution of volcanic earthquakes and ground deformations before and after eruptions. Temporal evolutions of multidiscipline data regarding the volcanic activity from October 2003 to January 2018 revealed that the supplied amount of magma from the magma chamber and the internal condition in the shallow regions of the conduit controlled the recent eruptions.
著者
Paul K. B. ALANIS Yusuke YAMAYA Akihiro TAKEUCHI Yoichi SASAI Yoshihiro OKADA Toshiyasu NAGAO
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.89, no.8, pp.383-389, 2013-10-11 (Released:2013-10-11)
参考文献数
20
被引用文献数
8 15

Taal Volcano is one of the most active volcanoes in the Philippines. The magnetotelluric 3D forward analyses indicate the existence of a large high resistivity anomaly (∼100 Ω·m) with a volume of at least 3 km × 3 km × 3 km, which is capped by a conductive layer (∼10 Ω·m), beneath the Main Crater. This high resistivity anomaly is hypothesized to be a large hydrothermal reservoir, consisting of the aggregate of interconnected cracks in rigid and dense host rocks, which are filled with hydrothermal fluids coming from a magma batch below the reservoir. The hydrothermal fluids are considered partly in gas phase and liquid phase. The presence of such a large hydrothermal reservoir and the stagnant magma below may have influences on the volcano’s activity. Two possibilities are presented. First, the 30 January 1911 explosion event was a magmatic hydrothermal eruption rather than a base-surge associated with a phreato-magmatic eruption. Second, the earlier proposed four eruption series may be better interpreted by two cycles, each consisting of series of summit and flank eruptions.(Communicated by Seiya Uyeda, M.J.A.)
著者
Tamao ENDO
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.95, no.1, pp.39-51, 2019-01-11 (Released:2019-01-11)
参考文献数
61
被引用文献数
38

Glycosylation is an important posttranslational modification in mammals. The glycans of glycoproteins are classified into two groups, namely, N-glycans and O-glycans, according to their glycan-peptide linkage regions. Recently, O-mannosyl glycan, an O-glycan, has been shown to be important in muscle and brain development. A clear relationship between O-mannosyl glycans and the pathomechanisms of some congenital muscular dystrophies has been established in humans. Ribitol-5-phosphate is a newly identified glycan component in mammals, and its biosynthetic pathway has been elucidated. The discovery of new glycan structures and the identification of highly regulated mechanisms of glycan processing will help researchers to understand glycan functions and develop therapeutic strategies.
著者
Yoshikatsu MATSUBAYASHI
出版者
The Japan Academy
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.94, no.2, pp.59-74, 2018-02-09 (Released:2018-02-09)
参考文献数
74
被引用文献数
24

The identification of hormones and their receptors in multicellular organisms is one of the most exciting research areas and has lead to breakthroughs in understanding how their growth and development are regulated. In particular, peptide hormones offer advantages as cell-to-cell signals in that they can be synthesized rapidly and have the greatest diversity in their structure and function. Peptides often undergo post-translational modifications and proteolytic processing to generate small oligopeptide hormones. In plants, such small post-translationally modified peptides constitute the largest group of peptide hormones. We initially explored this type of peptide hormone using bioassay-guided fractionation and later by in silico gene screening coupled with biochemical peptide detection, which led to the identification of four types of novel peptide hormones in plants. We also identified specific receptors for these peptides and transferases required for their post-translational modification. This review summarizes how we discovered these peptide hormone–receptor pairs and post-translational modification enzymes, and how these molecules function in plant growth, development and environmental adaptation.
著者
Toshiharu ICHINOSE Hiromu TANIMOTO
出版者
日本学士院
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.92, no.8, pp.346-357, 2016-10-11 (Released:2016-10-11)
参考文献数
50
被引用文献数
10

Memory retrieval requires both accuracy and speed. Olfactory learning of the fruit fly Drosophila melanogaster serves as a powerful model system to identify molecular and neuronal substrates of memory and memory-guided behavior. The behavioral expression of olfactory memory has traditionally been tested as a conditioned odor response in a simple T-maze, which measures the result, but not the speed, of odor choice. Here, we developed multiplexed T-mazes that allow video recording of the choice behavior. Automatic fly counting in each arm of the maze visualizes choice dynamics. Using this setup, we show that the transient blockade of serotonergic neurons slows down the choice, while leaving the eventual choice intact. In contrast, activation of the same neurons impairs the eventual performance leaving the choice speed unchanged. Our new apparatus contributes to elucidating how the speed and the accuracy of memory retrieval are implemented in the fly brain.
著者
Tsuguo SUNAMURA
出版者
日本学士院
雑誌
Proceedings of the Japan Academy, Series B (ISSN:03862208)
巻号頁・発行日
vol.91, no.9, pp.481-500, 2015-11-11 (Released:2015-11-11)
参考文献数
143
被引用文献数
2 62

Substantial progress in research on the recession of coastal cliffs composed of soft materials has been made in recent years and data with higher accuracy have been accumulated. This paper provides the state of the art review in the recession studies and highlights two new findings obtained from the reanalysis of existing data. The review topics are: episodic and localized nature of cliff recession; the development of cliffline; the relationship between cliff height and recession rate; mechanisms of cliff toe erosion by waves; a fundamental equation for wave-induced toe erosion; factors controlling toe erosion; and slope instabilities and mass movements. The findings are presented on (1) the temporal change in cliffline recession mode and (2) the effect of beach sediment at the cliff base on the cliff erosion.