University of the Ryukyus Repository

金城, 忠嗣

Kinjo, Tadatsugu

English

帝王切開既往例の妊娠後期における子宮下節の超音波評価

Chandra, Sumal

チャンドラ, シュマル

電子相関の強い系に対する第一原理運動量依存局所変分埋論 : 鉄の電子状態への応用

Mokodongan, Daniel Frikli

モコドンガン, ダニエル フリックリ

琉球大学学術リポジトリ
インドネシア・スラウェシ島固有のメダカ科魚類（
ダツ目）の系統学的および分類学的研究
言語: Japanese
出版者: 琉球大学
公開日: 2016-10-06
キーワード (Ja): 
キーワード (En): 
作成者: Mokodongan, Daniel Frikli, モコドンガン,
ダニエル フリックリ
メールアドレス: 
所属: 
メタデータ
http://hdl.handle.net/20.500.12000/35389URL
Abstract 
Although the family Adrianichthyidae is broadly distributed throughout East 
and Southeast Asia, 19 endemic species are distributed in Sulawesi, which is an island 
in Wallacea. However, it remains unclear how Adrianichthyidae biodiversity hotspot 
was shaped. Moreover, seven of the 19 endemic species were described within this 
decade, suggesting that we still do not know the full picture of the biodiversity of this 
family in this small island ofthe Indo-Australian Archipelago. 
First, I reconstructed molecular phylogenies for the Sulawesi adrianichthyids 
and estimated the divergence times of major lineages to infer the detailed history of 
their origin and subsequent intra-island diversification. The mitochondrial and nuclear 
phylogenies revealed that Sulawesi adrianichthyids are monophyletic, which indicates 
that they diverged from a single common ancestor. Species in the earliest branching 
lineages are currently distributed in the central and southeastern parts of Sulawesi, 
indicating that the common ancestor colonized Sula Spur, which is a large 
promontory that projects from the Australian continental margin, from Asia by 
tectonic dispersal c.a. 20 Mya. The first diversification event on Sulawesi, the split of 
the genus Adrianichthys, occurred c.a. 16 Mya, and resulted in the nesting of the 
genus Adrianichthys within Oryzias. Strong geographic structure was evident in the 
phylogeny; many species in the lineages branching off early are riverine and widely 
distributed in the southeastern and southwestern arms of Sulawesi, which suggests 
that oversea dispersal between tectonic subdivisions of this island during the late 
Miocene (7-5 Mya) contributed to the distributions and diversification of the early 
branching lineages. In contrast, most species in the lineages branched off later are 
endemic to a single tectonic lake or lake system in the central Sulawesi, suggesting 
that habitat fragmentation due to the Pliocene collisions (c.a. 4 Mya) among the 
tectonic subdivisions was the primary factor for diversification of the late branching, 
lacustrine lineages. Adrianichthys and some Oryzias in a certain late branching 
lineage are sympatric in Lake Poso, which indicates multiple colonizations of these 
distinct lineages into this tectonic lake. Thus, the diversification of Sulawesi 
adrianichthyids largely reflects the complex geological history of this island. 
Second, I examined morphological variation and phylogeny among nine local 
populations of the Oryzias woworae species group, composed of 0. asinua, 0. wolasi, 
and 0. woworae, which have been recently described from the southeastern part of 
Sulawesi, to see if they are really valid species or not. Multivariate analyses using 
morphometric measurements and phylogeny estimated using mitochondrial DNA 
sequences revealed that they cannot be separated both in morphology and phylogeny 
in a manner that is currently classified. Especially, 0. wolasi from the type locality 
and that from the locality of paratypes are morphologically distinguished and 
phylogenetically polyphyletic, suggesting that 0. wolasi is not a valid species in both 
morphological and phylogenetic species concepts. I found that morphometries of the 
nine populations may differ according to their habitat environments, especially to the 
water currents, probably reflecting local adaptation. These facts suggest that the three 
species of the 0. woworae species group may be merely ecotypes. 
Finally, I examined morphology of Oryzias soerotoi, which I have described 
from Lake Tiu, Central Sulawesi, during the course of field collections. Oryzias 
soerotoi is distinguished from all other species in the genus Oryzias in Sulawesi by 
combination of brilliant orange coloration in the dorsal and ventral margins of the 
caudal fins of adult males, 30-32 scales along the lateral midline, 9-10 pectoral-fin 
rays, head lengths of 21.9-24.9% SL, anal-fin base lengths of 23.7-29.7% SL, and 
maximum SL up to 32.1 mm. Aquarium observations revealed that the orange 
margins of the caudal fins of males become more brilliant during courtship. 
The estimated phylogenies revealed that male body colorations differed by clade, and 
that species having maternal care occur in distant clades. These suggest that the 
evolution of body coloration and maternal care may have played an important role in 
the intra-island diversification of Adrianichthyidae, although it remains to be seen 
what has driven the evolution of these clade-specific morphological and reproductive 
traits. Comparisons with other animal taxa may also help us to understand how the 
biodiversity hotspot of this "anomalous" island has been shaped. 


Japanese

インドネシア・スラウェシ島固有のメダカ科魚類（ダツ目）の系統学的および分類学的研究

Tran, Hai Minh

チャン, ハイ ミン

音響OFDMを用いた水中通信の高性能化に関する研究

早乙女, 理恵

Saotome, Rie

A Study of Marine and Underwater Radio Communication for Search of Marine Resources

Koku Hannadige, Rohitha Pradeep Kumara

コク ハンナディゲ, ロヒィタ プラディップ クマラ

食材性シロアリNasutitermes takasagoensisにおける組織複合域の生理学的機能に関するトランスクリプトーム解析

砂川, 智子

Sunagawa, Satoko

オセルタミビル予防投与によるインフルエンザ院内感染防止 : 観察研究と文献学的考察

Duangkaew, Sutpratana

ドゥアンケーオ, スットプラータナー

タイ・チェンマイにおける日本人長期滞在者のライフスタイル型の移動とそのインパクト

東新川, 実和

Higashiarakawa, Miwa

糞線虫感染時にみられる正常血清免疫グロプリンE値と末梢血好酸球数に関する研究

照屋, 淳志

Teruya, Atushi

琉球大学学術リポジトリ
コバルト化合物の相関電子状態
言語: English
出版者: 琉球大学
公開日: 2016-04-11
キーワード (Ja): 
キーワード (En): 
作成者: 照屋, 淳志, Teruya, Atushi
メールアドレス: 
所属: 
メタデータ
http://hdl.handle.net/20.500.12000/33505URL
~~JtMI'I 
rcorrelated electronic states in Co-based intermetallic compounds (::u{;v 1-{l::.g.liWJO);j:§~ill: 
-Ti7\!1~)J 
In the present study, we mainly grew high-quality single crystals of Co-based transition metal 
compounds and clarified the Fermi surface and magnetic properties by measuring the electrical 
resistivity, specific heat, magnetic susceptibility, magnetization, and de Haas~van Alphen 
(dHvA) effect, together with the help of energy band calculations done by Prof. Hisatomo 
Harima, Kobe University. Co-3d electrons are studied from a viewpoint of correlations, which 
induce magnetic moments and itinerant conduction electrons with the relatively large masses. 
First, we studied Fermi surface properties based on the dimensionality of electronic states for 
single crystals of V,Gas, CoGa,, TiGa,, and ZrGa, (ZrAI,) with different tetragonal structures. 
For example, a nearly one-dimensional plate-like Fermi surface is obtained in the band 
calculations for V2Ga5 with a flat tetragonal structure. The corresponding single crystal is of 
needle shape along the tetragonal [001) direction. Among these compounds mentioned above, the 
electronic specific heat coefficient yin V2Ga5 is determined as y ~ 16.7 mJ/(K
2·mol), which is 
compared with the theoretical one Yb ~ I 0.4 I mJ/(K2·mol). On the other hand, those of the other 
compounds are y/yb ~ 1.01-1.08. The present relatively large ratio y/yb ~ 1.60 in V2Ga5 is due to 
correlations of V~3d conduction electrons. Next, we studied a superconductor Zr2Co with a 
slightly larger effect of correlations, namely y/yb ~ 1.90 (y ~ 22.5 mJ/(K2 ·mol)). y in the 
superconducting state is found to increase not linearly but as a function of H 112 up to magnetic 
fields close to the upper critical field H,2, suggesting that Zr2Co is the BCS superconductor with 
an anisotropic gap, for example. We grew high-quality single crystals of SrCo2P2 which is 
known to be a nearly ferromagnetic compound, very close to a well-known compound YCo2 • 
Thus, y and the cyclotron effective masses m,' are large: y ~ 40 mJ/(K2 ·mol), 0.87~m/~7.2m0 
(m0 : rest mass of an electron). The dHvA experiments are well explained by the results of the 
energy band calculations. We also grew single crystals of a ferromagnet LaCozP2 and an 
antiferromagnet CaCo2P2 with an ordered moment of 0.4 and 0.3 fls/Co, respectively. For 
LaCo,P,, we also carried out the dHvA experiments. m,' of main dHvA branches are (2-3)m0 
which are compared with much larger cyclotron masses of (3-7)m0 in a nearly ferromagnet 
SrCo,P,. Note y ~ 19 mJ/(K2·mol) in LaCo2P2, which is half of that in SrCo2P2• 
From these experimental and theoretical results, Co-3d electrons in these compounds are 
itinerant and become main conduction electrons. Namely, the Fermi surfaces are mainly 
composed from Co~3d electrons. Correlations between these conduction electrons are reflected in 
the electronic specific heat, or the cyclotron mass. The. effect of correlations is largest in the 
nearly ferromagnet SrCo2P2 and becomes weak when the electronic states deviate from this 
ferromagnetic instability, revealing a Pauli paramagnetic state in CoGa3 and the 
ferromagnetically ordered state in LaCo2P2 


コバルト化合物の相関電子状態

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