ペロブスカイト型酸化物La0.6Sr0.4Co1-xFexO3-δ (0 ≤ x ≤ 1.0)の熱的性質

要約のみTohoku University川田達也課

Content-Based Unsupervised Fake News Detection on Ukraine-Russia War

The Ukrainian-Russian war has garnered significant attention worldwide, with fake news obstructing the formation of public opinion and disseminating false information. This scholarly paper explores the use of unsupervised learning methods and the Bidirectional Encoder Representations from Transformers (BERT) to detect fake news in news articles from various sources. BERT topic modeling is applied to cluster news articles by their respective topics, followed by summarization to measure the similarity scores. The hypothesis posits that topics with larger variances are more likely to contain fake news. The proposed method was evaluated using a dataset of approximately 1000 labeled news articles related to the Syrian war. The study found that while unsupervised content clustering with topic similarity was insufficient to detect fake news, it demonstrated the prevalence of fake news content and its potential for clustering by topic

Catalogue of herpetological specimens of the Ewha Womans University Natural History Museum (EWNHM), Republic of Korea

The herpetology collection of the Ewha Womans University Natural History Museum (EWNHM) represents one of the oldest and largest institutional collections in the Republic of Korea. The specimens deposited in the EWNHM represent a major historical collection of the native herpetofauna, both in species diversity and time span. However, the full inventory of the herpetology collection has never been conducted and thus the collection has received little attention from researchers. Here, the first full account of the herpetology specimens held at the EWNHM is provided, with voucher information for all documented specimens to make the collection accessible for future studies

Yellow sea mediated segregation between North East AsianDryophytesspecies

While comparatively few amphibian species have been described on the North East Asian mainland in the last decades, several species have been the subject of taxonomical debates in relation to the Yellow sea. Here, we sampledDryophytessp. treefrogs from the Republic of Korea, the Democratic People's Republic of Korea and the People's Republic of China to clarify the status of this clade around the Yellow sea and determine the impact of sea level change on treefrogs' phylogenetic relationships. Based on genetics, call properties, adult morphology, tadpole morphology and niche modelling, we determined the segregated status species ofD.suweonensisandD.immaculatus. We then proceeded to describe a new treefrog species,D.flaviventrissp. nov., from the central lowlands of the Republic of Korea. The new species is geographically segregated fromD.suweonensisby the Chilgap mountain range and known to occur only in the area of Buyeo, Nonsan and Iksan in the Republic of Korea. While the Yellow sea is the principal element to the current isolation of the three clades, the paleorivers of the Yellow sea basin are likely to have been the major factor for the divergences within this clade. We recommend conducting rapid conservation assessments as these species are present on very narrow and declining ranges

Content-Based Unsupervised Fake News Detection on Ukraine-Russia War

The Ukrainian-Russian war has garnered significant attention worldwide, with fake news obstructing the formation of public opinion and disseminating false information. This scholarly paper explores the use of unsupervised learning methods and the Bidirectional Encoder Representations from Transformers (BERT) to detect fake news in news articles from various sources. BERT topic modeling is applied to cluster news articles by their respective topics, followed by summarization to measure the similarity scores. The hypothesis posits that topics with larger variances are more likely to contain fake news. The proposed method was evaluated using a dataset of approximately 1000 labeled news articles related to the Syrian war. The study found that while unsupervised content clustering with topic similarity was insufficient to detect fake news, it demonstrated the prevalence of fake news content and its potential for clustering by topic

Is ultra-violet fluorescence a trait related to breeding in the Mongolian racerunner (Eremias argus; Lacertidae, Reptilia)?

Ornamental traits such as ultraviolet (UV) fluorescence and reflectance can provide honest signals indicating the bearer’s condition as a potential mate. UV fluorescence is widely found in nature and used for multiple functions, such as indicating female maturity in arachnids and acting as a signal enhancer in many insects. Lizards can display a broad range of colours, but the function of some of their ornamental traits remains unclear. Here, we report the presence of UV fluorescence in female Eremias argus specimens, a small lizard ranging across Mongolia, China and the Korean Peninsula. Based on our observation, combined with the literature on the breeding behaviour of the species, we provide two hypotheses, assigning the use of UV fluorescence to: 1) an indicator of females body conditions and 2) signal efficacy backup. To verify our hypotheses, we suggest a protocol with three serial trials under low light and enhanced UV light conditions.

A revision of the genus Littorina (Mollusca: Gastropoda) in Korea

Littorina Férussac, 1822 is an abundant genus of small gastropods found in the upper littoral zone of rocky seashores worldwide. Although ecologically important, shell-based species identification in this genus is challenging due to phenotypic variation in shell morphology and lack of diagnostic characters among morphologically similar species. In this study, we revised the taxonomy of Korean Littorina species using morphological characters (shell and radula) and cox1 mitochondrial DNA sequences for three Korean species: L. brevicula, L. sitkana, and L. horikawai. Results suggest that L. sitkana was erroneously reported as L. kasatka in a previous study. A new record for Littorina horikawai (Matsubayashi & Habe in Habe, 1979), previously unknown from Korea, is described, which can be distinguished from L. sitkana by the presence of alternating white and brown spiral ribs on each whorl. Comparison of the mtDNA cox1 gene sequences shows very low intraspecific variation even between geographically distant populations. A phylogenetic tree supports a close relationship between L. horikawai and L. sitkana, consistent with earlier phylogenetic studies

Life-history features and oceanography drive phylogeographic patterns of the chiton Acanthochitona cf. rubrolineata (Lischke, 1873) in the northwestern Pacific

Chitons are a group of marine mollusks (class Polyplacophora) characterized by having eight articulating shell plates on their dorsal body surface. They represent suitable materials for studying the spatiotemporal processes that underlie population differentiation and speciation in ocean environments. Here we performed population genetic analyses on the northwestern Pacific chiton Acanthochitona cf. rubrolineata (Lischke, 1873) using two mitochondrial gene fragments (COI and 16S) from 180 individuals sampled from 11 populations among the coastal waters of Korea, Japan, and China. The phylogenetic network uncovered a reticulated relationship with several sub-haplogroups for all A. cf. rubrolineata haplotypes. SAMOVA analyses suggested the best grouping occurred at three groups (ΦCT = 0.151, P < 0.0001), which geographically corresponds to hydrographic discontinuity among the coastal regions of Korea, Japan, and China. The assumed limited dispersal ability of A. cf. rubrolineata, coupled with northeasterly flowing, trifurcate warm currents, might have contributed to the genetic differentiation among the three groups. Meanwhile, a high level of within-group genetic homogeneity was detected, indicating extensive coastal currents might facilitate gene flow among the populations within each group. Bayesian skyline plots demonstrated significant population expansion after the Last Glacial Period (110-25 thousand years ago) for all studied populations except the Japan group. Together these results suggest that the present-day phylogeographic patterns of A. cf. rubrolineata are strongly affected by the interplay of historical and/or contemporary oceanography and species-specific life-history features

Update on Distribution and Conservation Status of Amphibians in the Democratic People’s Republic of Korea: Conclusions Based on Field Surveys, Environmental Modelling, Molecular Analyses and Call Properties

Determining the range, status, ecology and behaviour of species from areas where surveys and samplings are uncommon or difficult to conduct is a challenge, such as in the Democratic People’s Republic of Korea (DPR Korea). Here, we used genetic samples, field surveys, call recordings, photographic identification and a literature review to estimate the presence, range and status of amphibians in the DPR Korea. From our combined results and based on the IUCN Red List categories and criteria, we were able to estimate the national threat levels for most species. Our results demonstrated the presence of 18 native species and the suspected presence of Karsenia koreana and two Onychodactylus species. We reported the first record for Rana uenoi in the vicinity of Pyongyang using molecular tools and similarly confirmed the presence of Dryophytes japonicus at the same location. Based on distribution and modelling, we can expect the contact zone between species within the Rana and Onychodactylus genera to be located along the Changbai Massif, a mountain range that marks a shift in ecoregions and acts as a barrier to dispersion. The species richness was higher in the lowlands and at lower latitudes, with such areas populated by up to 11 species, while more northern regions were characterised by species richness of about half of that value. The combination of ecological models and known threats resulted in the recommendation of ten species as threatened at the national level following the IUCN Red List categories and criteria. This high number of threatened species was anticipated based on the high threat level to amphibians in bordering nations and globally. While the ecology of species in the DPR Korea is still understudied, we argue that species relying on agricultural wetlands such as rice paddies are not under imminent threat due to the enduring presence of extensive agricultural landscapes with low rates of chemical use and mechanisation. The maintenance of such landscapes is a clear benefit to amphibian species, in contrast to more industrialised agricultural landscapes in neighbouring nations. In comparison, the status of species dependent on forested habitats is unclear and threat levels are likely to be higher because of deforestation, as in neighbouring nations