Tatsuo Izawa

Okinawa University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Liam O’Shaughnessy

Vrije Universiteit Amsterdam

Joshua W. Shaevitz

Princeton University

Greg J. Stephens

Vrije Universiteit Amsterdam

Ichiro Masai

Okinawa Institute of Science and Technology Graduate University

Tetsuya Theodore. Fujita

University of Toyama

Kazuo Watanabe

The University of Texas at Austin

Lourdes Peña‐Castillo

Memorial University of Newfoundland

Hiromi Ohta

Kindai University

Greg Stephens

Pranjal Patra

Memorial University of Newfoundland

Cooperative Institutions

Okinawa Institute of Science and Technology Graduate University

Vrije Universiteit Amsterdam

Institute for Atomic and Molecular Physics

Wageningen University & Research

Princeton University

Osaka University

Kyoto University

Memorial University of Newfoundland

Okinawa University

Los Alamos National Laboratory

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

"Relationship between Observed Winds and Cloud Velocities Determined from Pictures Obtained by ESSA III, ESSA V, and ATS I satellites," by Izawa, T. and Fujita, T. in Cospar Space Research IX, North-Holland Publishing Co., Amsterdam, p. 571-579, 1969.

Tetsuya Theodore. Fujita Tatsuo Izawa

Fujita scale

Source

Cite

Citations (0)

Dynamics of dominance: maneuvers, contests, and assessment in the posture-scale movements of interacting zebrafish

bioRxiv (Cold Spring Harbor Laboratory) (2023)

Liam O’Shaughnessy Tatsuo Izawa Ichiro Masai Joshua W. Shaevitz Greg J. Stephens

While two-body fighting behavior occurs throughout the animal kingdom to settle dominance disputes, important questions such as how the dynamics ultimately lead to a winner and loser are unresolved. Here we examine fighting behavior at high-resolution in male zebrafish. We combine multiple cameras, a large volume containing a transparent interior cage to avoid reflection artifacts, with computer vision to track multiple body points across multiple organisms while maintaining individual identity in 3D. In the body point trajectories we find a spectrum of timescales which we use to build informative joint coordinates consisting of relative orientation and distance. We use the distribution of these coordinates to automatically identify fight epochs, and we demonstrate the post-fight emergence of an abrupt asymmetry in relative orientations-a clear and quantitative signal of hierarchy formation. We identify short-time, multi-animal behaviors as clustered transitions between joint configurations, and show that fight epochs are spanned by a subset of these clusters, which we denote as maneuvers. The resulting space of maneuvers is rich but interpretable, including motifs such as “attacks” and “circling”. In the longer-time dynamics of maneuver frequencies we find differential and changing strategies, including that the eventual loser attacks more often towards the end of the contest. Our results suggest a reevaluation of relevant assessment models in zebrafish, while our approach is generally applicable to other animal systems.

CONTEST

Dominance (genetics)

10.1101/2023.11.21.567896

Cite

Citations (4)

Cool storage of the Japanese eel (Anguilla japonica) spermatozoa

Hiromi Ohta Tatsuo Izawa

Japanese eel

Source

Cite

Citations (3)

Some Considerations on the Continuous Space-time Spectral Analysis of Atmospheric Disturbances

Papers in Meteorology and Geophysics (1972)

Tatsuo Izawa

熱帯太平洋のような地球上の限られた領域からサンプルされた空-時系列の西進波と東進波の成分をもつ連続空-時スペクトルを空-時共分散のフーリエ変換として推定する問題について述べる。従来空-時スペクトルの研究は主として緯度圏に沿って全地球的にサンプルされた空-時系列の時間的には連続ではあるが空間的には不連続な場合についてのみ行あれてきたので,本論文の始めでは従来の研究との関係を明らかにするためいくつかの型の空-時スペクトルについても議論される。第1章では先づ西進波と東進波の成分をもつ空間的にも時間的にも不連続な空-時スペクトルが空-時平均により定義された共分散のフーリエ変換として与えられる。次にこのような空-時スペクトルの1つの極限として空間的には不連続であるが時間的には連続な空-時スペクトルが導かれ,更にその極限として空間的にも時間的にも連続な空-時スペクトルが導かれる。不連続スペクトルと連続スペクトルの関係も議論される。空-時系列の統計的研究では空-時スペクトルは母集合平均により定義された空-時共分散のフーリエ変換として与えられる。第2章ではこのように定義された一般化された空-時スペクトルには9つの異った空-時スペクトルの和として表わされることが示される。空-時スペクトルが空間的にも時間的にも絶対連続の場合には空-時スペクトル密度が存在する。統計的に云うと,第1章で述べた連続空-時スペクトルは連続な空間および時間に対して存在すると仮定される連続係数空-時系列の標本空-時スペクトルを意味する。然し多くの場合,連続係数空-時系列は空間的にも暗間的にも等間隔な不連続係数空-時系列としてサンプルされるので,この場合生じる偽波数-周波数の問題についても簡単に述べる。次にこのようにサンプルされた空-時スペクトルは或る確率法則で母空-時スペクトル密度に収束することが要求される。ここでは標本空-時スペクトルが母空-時スペクトル密度の一致推定量になるために標本空-時スペクトルを平滑する2つの空-時スペクトル窓関数について述べる。次にこのようにして平滑された空-時スペクトルの大標本的性質が調べられ,x2-分布に基く標本分布の近似が導かれる。連続係数空-時系列を不連続空-時系列としてサンプルしたときに起る重要な問題の1つは低波数-周波数の波が他の波より大きな値を示すことである-第3章では低波数一周波数の波を消し,綜観規模の波だけを残す2つの型の高波数-周波数通過フィルター-が提案される。或る場合には超高波数-周波数の波は信号としてでなく雑音として現われることがある。このため超低波数-周波数と同様に超高波数-周波数の波を消し,綜観規模波動のみを残す中間波数-周波数通過フィルタ-についても述べる。フィルターされた空-時スペクトルとフィルターされない空-時スペクトルの関係も簡単に議論される。

10.2467/mripapers1950.23.2_33

Cite

Citations (2)

Statistical Aspects of Lower Atmospheric Disturbances Delineated from Conventional and Satellite Data Over the Tropical Pacific

Papers in Meteorology and Geophysics (1972)

Tatsuo Izawa

エッサ気象衛星の気候学的雲写真上に明確な積算雲分布として現われる熱帯太平洋の平均下層大気とその擾乱の特性を統計的に調べた。北半球の夏では太平洋の気候学的雲写真は西から南東に伸びる赤道無雲帯により分離された2つの明察な雲帯を示す。月平均の地上気圧と風速場の解析から北側の雲帯は赤道収束帯(ITCZ)に関連しており,一方南側の雲帯は南太平洋の極トラフに関連していることが分る。これらの雲帯は顕著な低気圧性渦度と収束,風向の低い定常性,気圧および風の東西,南北成分における大きな分散により特徴づけられている。赤道無雲帯は西太平洋の赤道トラフと東太平洋の赤道リッジに関連しており,顕著な負渦度と発散,風向の比較的高い定常性,気圧および風の比較的小さい分散により特徴づけられている。このような平均の気圧場および風速場における局地変動の周波数スペクトル解析によると4-5日週期がITCZの北側と南太平洋の極トラフに卓越していることが分る。西から南東に伸びる赤道無雲帯では西太平洋の4-5日週期,東太平洋の8-10日週期が顕著である。太平洋の緯度圏に沿って取られた空-時系列のスペクトル解析によると,ITCZ内の10°N近くでは波長2,500km週期4-5日をもって西進する偏東風波動がみられるが,この波動は20°Nで最も顕著になる。6日週期で東進する波長5,000kmの波動は30°Nで観測されるが,それは5,000km聞隔で東進する北太平洋亜熱帯高気圧として追跡出来る。一方20°Sでは4-5日週期と10日週期をもって偏東風(基本流)と逆向きに東進する波長5,000kmの波動が観測されるが,これは5,000km間隔で東進する南太平洋亜熱帯高気圧として追跡出来る。10°Sと10°Nの間の赤道地方では6日週期と10日週期をもって西進する波長6,000kmの波動が観測されるが,これらは6,000kmの間隔で西進する赤道高気圧または赤道リッジとして追跡できる。風の東西および南北成分の相関解析によると,擾乱による東風運動量の南内き輸送がITCZの北側で起り,一方北向き輸送がITCZの南側で起っており,擾乱による東風運動量の収束がITCZに沿って起っていることを示唆している。空-時系列のコースペクトル解析によると10°Nで東風運動量の北向き輸送が5.5日週期をもって東進する波長4,000kmの波動により起り,一方南向きの輸送は5.5日週期をもって西進する波長2,500kmの波動により起っている。後者は偏東風波動によるものである。偏東風波動による東風運動量の南向き輸送は20°Nで最も顕著である。

Statistical Analysis

Tropical Eastern Pacific

10.2467/mripapers1950.23.2_73

Cite

Citations (2)

Formation and Structure of Equatorial Anticyclones Caused by Large-Scale Cross-Equatorial Flows Determined by ATS-I Photographs

Journal of applied meteorology (1969)

Tetsuya Theodore. Fujita Kazuo Watanabe Tatsuo Izawa

Because of poor coverage by synoptic stations, the tropical circulation over the eastern Pacific has not been known too well. As a result of photographic experiments, using the geosynchronous ATS-I satellite, fields of cloud motion over the eastern equatorial Pacific were mapped in detail on a number of days in September 1967. It was found that a large-scale flow from the Southern Hemisphere recurves after crossing the equator to form an anticyclone centered around 10N. Dynamical characteristics of this type of anticyclone were investigated by estimating the vorticity dissipating force from computed values of divergence and vorticity of low-cloud velocities determined from successive ATS-I pictures. The vorticity dissipating force seems to be related closely to the sea-surface temperature which would reduce the frictional coupling between the low-level atmosphere and the underlying sea surface. It was found that the anticyclone in its development stage results in a discontinuity of the intertropical band of cloudiness, before it travels westward with an active cloud band along its leading edge. Based upon evidence found through case studies, a model of an equatorial anticyclone is proposed in this paper. Numerical computations of cross-equatorial trajectories were performed by using the divergence-vorticity relationships and the vorticity dissipating force, which were obtained through numerical analyses. This paper thus presents an initial step toward the further development of tropical synoptic meteorology, which is expected during the next few years as a result of photographic experiments using the ATS-I and III.

Anticyclone

10.1175/1520-0450(1969)008<0649:fasoea>2.0.co;2

Cite

Citations (39)

REPA: Applying Pathway Analysis to Genome-Wide Transcription Factor Binding Data

IEEE/ACM Transactions on Computational Biology and Bioinformatics (2015)

Pranjal Patra Tatsuo Izawa Lourdes Peña‐Castillo

Pathway analysis has been extensively applied to aid in the interpretation of the results of genome-wide transcription profiling studies, and has been shown to successfully find associations between the biological phenomena under study and biological pathways. There are two widely used approaches of pathway analysis: over-representation analysis, and gene set analysis. Recently genome-wide transcription factor binding data has become widely available allowing for the application of pathway analysis to this type of data. In this work, we developed regulatory enrichment pathway analysis (REPA) to apply gene set analysis to genome-wide transcription factor binding data to infer associations between transcription factors and biological pathways. We used the transcription factor binding data generated by the ENCODE project, and gene sets from the Molecular Signatures and KEGG databases. Our results showed that 54 percent of the predictions examined have literature support and that REPA's recall is roughly 54 percent. This level of precision is promising as several of REPA's predictions are expected to be novel and can be used to guide new research avenues. In addition, the results of our case studies showed that REPA enhances the interpretation of genome-wide transcription profiling studies by suggesting putative regulators behind the observed transcriptional responses.

ENCODE

KEGG

DNA binding site

Transcription

Profiling (computer programming)

10.1109/tcbb.2015.2453948

Cite

Citations (6)

One fish, two fish, win fish, lose fish: Imaging and analyzing the fighting behavior of zebrafish in 3D

Bulletin of the American Physical Society (2020)

Liam O’Shaughnessy Tatsuo Izawa Ichiro Masai Joshua W. Shaevitz Greg Stephens

Source

Cite

Citations (0)

Dynamics of Dominance in Interacting Zebrafish

PRX Life (2024)

Liam O’Shaughnessy Tatsuo Izawa Ichiro Masai Joshua W. Shaevitz Greg J. Stephens

While two-body fighting behavior occurs throughout the animal kingdom to settle dominance disputes, important questions such as how the dynamics ultimately lead to a winner and loser are unresolved. Here we examine fighting behavior at high resolution in male zebrafish. We combine multiple cameras, a large volume containing a transparent interior cage to avoid reflection artifacts, with computer vision to track multiple body points across multiple organisms while maintaining individual identity in three dimensions. In the body point trajectories we find a spectrum of timescales which we use to build informative joint coordinates consisting of relative orientation and distance. We use the distribution of these coordinates to automatically identify fight epochs, and we demonstrate the postfight emergence of an abrupt asymmetry in relative orientations—a clear and quantitative signal of hierarchy formation. We identify short-time, multi-animal behaviors as clustered transitions between joint configurations, and show that fight epochs are spanned by a subset of these clusters, which we denote as maneuvers. The resulting space of maneuvers is rich but interpretable, including motifs such as “attacks” and “circling.” In the longer-time dynamics of maneuver frequencies we find differential and changing strategies, including that the eventual loser attacks more often towards the end of the contest. Our results suggest a reevaluation of relevant assessment models in zebrafish, while our approach is generally applicable to other animal systems. Published by the American Physical Society 2024

Dominance (genetics)

Dynamics

10.1103/prxlife.2.043006

Cite

Citations (1)

Quantifying the pairwise fighting behavior of zebrafish in 3D

Bulletin of the American Physical Society (2021)

Liam O’Shaughnessy Tatsuo Izawa Joshua W. Shaevitz Greg J. Stephens

Source

Cite

Citations (0)