Mating activity of a wild Mueller’s gibbon group was observed in the Danum Valley Conservation Area, Sabah, Malaysia. The purpose of this study was to investigate the function of copulation calls in gibbons. The female emitted copulation calls at the time of intromission and pelvic thrusting. Copulation calls were composed of two notes and one of them was sung only while mating. Approximately half of copulation calls were sung near the range boundary. Mating with copulation calls sometimes occurred while singing. (...) According to the model that female copulation calls have evolved under the selective pressures of risk of infanticide and sperm competition, copulation calls should be rare in species with little female promiscuity. As gibbons usually live in pair-living social organization and have a monogamous mating system, no vocal signals by female gibbons are considered to be needed. However, clear copulation calls were emitted by the female. It suggests that the relationship between paired gibbons is unstable. Copulation calls by the female Mueller’s gibbon may function to increase mate guarding and strengthen the pair bond. (shrink)

Songbirds possess mirror neurons (MNs) activating during the perception and execution of specific features of songs. These neurons are located in high vocal center (HVC), a premotor nucleus implicated in song perception, production and learning, making worth to inquire their properties and functions in vocal recognition and imitative learning. By integrating a body of brain and behavioral data, we discuss neurophysiology, anatomical, computational properties and possible functions of songbird MNs. -/- We state that the neurophysiological properties of songbird MNs depends (...) on sensorimotor regions that are outside the auditory neural system. Interestingly, songbirds MNs can be the result of the specific type of song representation possessed by some songbird species. At the functional level, we discuss whether songbird MNs are involved in others' song recognition, by dissecting the function of recognition in various different but possible overlapping processes: action-oriented perception, discriminative-oriented perception and identification of the signaler. We conclude that songbird MNs may be involved in recognizing other singer's vocalizations, while their role in imitative learning still require to solve how auditory feedback are used to correct own vocal performance to match the tutor song. Finally, we compare songbird and human mirror responses, hypothesizing a case of convergent evolution, and proposing new experimental directions. (shrink)

Male white-rumped munias sing syntactically simpler songs than their domestic counterparts, Bengalese finches. The differences in song structure may reflect differences in natural selection pressures between wild and domestic environments. Deacon (2010) proposed song simplicity of the wild strain could be subject to natural selection. We hypothesized the selection pressure may be species identification. Thus, we compared song variations in relation to ecological factors and dispersal history of white-rumped munias to understand song evolutionary processes. We found geographic variations of song (...) syntactical complexity. The difference of song syntactical complexity did not corresponded to genetic distance, but did to that of the proportion of mixed flocks with sympatric related species. Birds that inhabited the areas with more mixed flocks sang simpler songs. The song complexity might be constrained to intensify distinct conspecific signals from related species. Our field work provided empirical evidence supporting a proposal made by Deacon (2010). Keywords: birdsong; evolution; masking hypothesis; Bengalese finches; song geographic variation; genetic variation. (shrink)

Male white-rumped munias sing syntactically simpler songs than their domestic counterparts, Bengalese finches. The differences in song structure may reflect differences in natural selection pressures between wild and domestic environments. Deacon proposed song simplicity of the wild strain could be subject to natural selection. We hypothesized the selection pressure may be species identification. Thus, we compared song variations in relation to ecological factors and dispersal history of white-rumped munias to understand song evolutionary processes. We found geographic variations of song syntactical (...) complexity. The difference of song syntactical complexity did not corresponded to genetic distance, but did to that of the proportion of mixed flocks with sympatric related species. Birds that inhabited the areas with more mixed flocks sang simpler songs. The song complexity might be constrained to intensify distinct conspecific signals from related species. Our field work provided empirical evidence supporting a proposal made by Deacon. Keywords: birdsong; evolution; masking hypothesis; Bengalese finches; song geographic variation; genetic variation. (shrink)

Understanding whether the long and elaborate songs of male gibbons have syntax and hierarchical structures is an interesting question in the evolution of language, because gibbons are near humans in the phylogenetic tree and a hierarchically organized syntax is considered to be a basic component of human language. We conducted field research at Danum Valley Conservation Area in northern Borneo to test the hypothesis that gibbon songs have syntax and chunks. We followed one Mueller’s gibbon group for 1 week in (...) the dry and rainy seasons every year from 2001 to 2009, collecting vocal and behavioral data. Results show that songs emitted by the studied male gibbon were governed by combinatory rules. Some context-dependent songs had different combinatory rules, although they overlapped with the songs whose contexts were uncertain. The male Mueller’s songs had characteristics that suggest existence of chunk structure. These results provided an important perspective in the study of language origin. (shrink)

Mueller's gibbons ( Hylobates muelleri ) sing both sex-specific and duet songs. These songs are thought to be involved in territory maintenance, as well as the maintenance of pair or family bonds. However, few observational studies have examined how gibbons interact with their neighbors through song in the wild. We have been conducting field observations of wild gibbon groups in northeast Borneo since 2001. In the Borneo Rainforest Lodge (BRL) and Danum Valley Field Center (DVFC) at the Danum Valley Conservation (...) Area (DVCA), we observed seven episodes of alternating songs between males. Here, we describe the process of song exchange between males. During male interactions, song bouts rarely overlapped and were alternately emitted. Several studies have reported antiphonal vocalizations in New World and Old World primate species, but rarely in apes. Our observations of antiphonal songs in gibbons indicate that gibbons not only unilaterally advertise information, but also interactively communicate with neighbors and family members through songs. Since gibbons are phylogenetically similar to humans, and turn-taking has an important role in human conversation, our research on gibbon communication may provide insight into the evolution of human language. (shrink)

Mueller’s gibbons sing both sex-specific and duet songs. These songs are thought to be involved in territory maintenance, as well as the maintenance of pair or family bonds. However, few observational studies have examined how gibbons interact with their neighbors through song in the wild. We have been conducting field observations of wild gibbon groups in northeast Borneo since 2001. In the Borneo Rainforest Lodge and Danum Valley Field Center at the Danum Valley Conservation Area, we observed seven episodes of (...) alternating songs between males. Here, we describe the process of song exchange between males. During male interactions, song bouts rarely overlapped and were alternately emitted. Several studies have reported antiphonal vocalizations in New World and Old World primate species, but rarely in apes. Our observations of antiphonal songs in gibbons indicate that gibbons not only unilaterally advertise information, but also interactively communicate with neighbors and family members through songs. Since gibbons are phylogenetically similar to humans, and turn-taking has an important role in human conversation, our research on gibbon communication may provide insight into the evolution of human language. (shrink)

Male white-rumped munias sing syntactically simpler songs than their domestic counterparts, Bengalese finches. The differences in song structure may reflect differences in natural selection pressures between wild and domestic environments. Deacon proposed song simplicity of the wild strain could be subject to natural selection. We hypothesized the selection pressure may be species identification. Thus, we compared song variations in relation to ecological factors and dispersal history of white-rumped munias to understand song evolutionary processes. We found geographic variations of song syntactical (...) complexity. The difference of song syntactical complexity did not corresponded to genetic distance, but did to that of the proportion of mixed flocks with sympatric related species. Birds that inhabited the areas with more mixed flocks sang simpler songs. The song complexity might be constrained to intensify distinct conspecific signals from related species. Our field work provided empirical evidence supporting a proposal made by Deacon. Keywords: birdsong; evolution; masking hypothesis; Bengalese finches; song geographic variation; genetic variation. (shrink)

京都を知る，アルゴリズムを知る。アルゴリズムとはそもそも，何か物事を行うときの“具体的手順”のことである。私たちは日々，意識するかしないかに関わらず，次々とアルゴリズムの設計をしながら生活をしている。 本書は，岩間一雄教授が京都の町を題材にアルゴリズムの思考を伝える，読み物的手法をとった数学書である。読者はその奥深い世界へと誘われてゆくだろう。 巻末には本書で取り上げた京都関連の名所・行事などの索引があり，逆引きで読んでいくことができる。 【目次】 1．斜め横断 2．アイドルタイム 3．人事部長の悩み 4．チームワーク 5．神様との勝負 6．アルゴリズムからメカニズムへ 7．一番でなくとも 8．千年に1回も起こらない 9．自分のページランクを上げたい 10．対話のアルゴリズム 11．ビットコインの素晴らしさ 12．P対NP問題：ノーベル賞以上？ 13．アルゴリズムから見た進化論.

解きやすい離散最適化問題に対して統一的な枠組を与える「離散凸解析」の全体像を平易に解説.

日本古来の神々の色、陰陽五行説の色、武将たちに愛された色、雅な平安の色、粋な大江戸の色彩から、昭和の流行色まで、ビジュアルで辿る日本の色を探る旅。.

本書は、生活者のハピネス(豊かさや幸せ)の視点から科学技術や社会の変革を考える『因果関係から相関へ、個別技術からシステムへ』と題した『武田シンポジウム2018』の内容をまとめたものです。昨今最も注目を 浴びている科学技術である「AI」、「免疫システム研究」、「民間宇宙ロケット開発」の3つと異なる切り口から、ビッグデータと言われる時代の科学の方法論、個の集積以上の意味をもつシステムとしてのアプローチに ついて立体的に考察します。.