Island Of Japan Research Articles

Language standardization and railway-walking distance. Levenshtein distance and distribution in GAJ

Abstract In this paper, new quantitative methods were applied to elucidate the geographical distribution of Japanese dialects. (1) Regional differences (individual differences) of usage rate of standard language at each locality in GAJ (Grammar Atlas of Japanese Dialects) were dealt with. (2) In addition to the railway distance from Tokyo to each locality, the walking distance from the railway stations to the survey localities was measured and used as the “railway-walking distance”. (3) Using a scatter-plot in what is called a “limestone cave model”, the values on the axis of standard language usage were reversed, and the Japan Islands were divided into east and west according to their direction from Tokyo. It showed that the standard language usage rate and distance show a proportional relationship even at each locality (individual informant) value. (4) Focusing on the prefectures near Tokyo, the distance from Tokyo regulates the usage rate. From this, the rapid spread of standard language from modern Tokyo and influence of railway can be ascertained. It was found that the phenomena pointed out by the average values by prefectures of vocabulary items in LAJ are valid to the data for each locality (individual) of GAJ.

Population genetic differentiation and structure of rare plant Anemone shikokiana based on genotyping-by-sequencing (GBS)

BackgroundAnemone shikokiana (Makino) Makino is a perennial herb of the genus Anemone in the family Ranunculaceae. Endemic to the Shandong Peninsula in China and Shikoku Island in Japan, it is a rare and endangered plant with a narrow, disjunct distribution. It is threatened with extinction and is in urgent need of conservation. Evaluating the genetic diversity of species, revealing the population genetic structure and gene flow, and inferring the population history are of great importance for species conservation, especially for rare and endangered plants.ResultsIn our study, 73 samples from eight wild populations in China were sequenced by Super-GBS, yielding a total of 40.59 G clean reads and 52,231 SNPs. Based on the obtained SNP data set, we evaluated the population genetic diversity, genetic structure, and gene flow of A. shikokiana. A low level of genetic diversity was found (He = 0.1925, Ho = 0.1422). The neighbor-joining (NJ) tree, principal component analysis and ADMIXTURE analysis suggested that these 73 A. shikokiana could be considered as two groups. Pairwise genetic differentiation coefficients (Fst) indicated that genetic differentiation was lower between adjacent populations and higher between geographically separated populations. The gene flow between Kunyu Mountain and Lao Mountain was very low. However, neither of the two regions showed evidence of Isolation by Distance.ConclusionsHere, we revealed the population genetic structure and gene flow of A. shikokiana from the Shandong Peninsula, China. This research provides valuable genetic resources for A. shikokiana and contributes to the scientific and effective conservation of the species.

Description of Ixodeslanigeri sp. nov., a new hard tick species (Acari, Ixodidae) collected from mouse-eared bats (Vespertilionidae, Myotis) in Vietnam.

Historically, for more than one and a half centuries, only one so-called "long-legged bat tick" species, i.e., Ixodesvespertilionis Koch was known to science. However, during the past decade, it was recognized on a molecular basis that long-legged ixodid ticks associated with bats may represent at least six species. Of these, until recently, five have been morphologically described. In this study, Ixodes ticks were collected from two Myotis species in southeastern Asia, Vietnam. Based on the morphological and molecular characteristics of the female, nymph and larva, Ixodeslanigeri Hornok, sp. nov. is described here. The male is unknown. Like other members of the Ixodesariadnae complex, I.lanigeri Hornok apparently shows a preference for vesper bats as its typical hosts. In this context, host-association and geographical separation may explain the evolutionary divergence of I.lanigeri Hornok from its closest relative occurring on Murinahilgendorfi Peters in East Asia, Japan, because no Myotis or Murina spp. have overlapping distribution between Vietnam and the main islands of Japan. On the other hand, supposing that (similarly to I.ariadnae) I.lanigeri Hornok probably occurs on other myotine bats and knowing that several Myotis species indigenous in Vietnam have a broad geographical range in southern and southeastern Asia, the new tick species most likely has a widespread distribution in this area.

1118. Dendrocacalia crepidifolia (Nakai) Nakai: Compositae

SummaryThe monotypic genus Dendrocacalia (Nakai) Nakai, with the species Dendrocacalia crepidifolia (Nakai) Nakai, a large shrub or small tree from the Bonin Islands or Ogasawara of Japan, is described and illustrated. Its ecology, pollination, dioecy and conservation are discussed; a detailed description is given. The species is now apparently restricted to the Haha‐jima island group, where the largest number of populations exist on Haji‐jima itself. Threats to its conservation are from two invasive trees, Ficus microcarpa and Psidium littorale.

Distribution of microplastics on sandy beaches in western and southern Japan and their fate in the oceans

The Japanese archipelago is surrounded by the Sea of Japan, the Sea of Okhotsk, the Pacific Ocean, and the East China Sea. The oceans are known to be contaminated by waste artifacts (marine litter). To investigate how these artifacts contaminate sandy beaches in Japan and their fate in the oceans, we sampled sand from 19 sandy beaches ranging from the western area of the main island of Japan (Honshu), which faces the Sea of Japan, to the westernmost island in the Japanese archipelago (Yonaguni Island), which faces the East China Sea. Almost all beaches were contaminated by marine litter. The maximum density by number of pieces was 604,600 per m3 in a 2-cm depth of sand on Yonaguni Island. Polystyrene foam was the most common artifact, and plastic fragments were second. The densities of artifacts by number and weight, and the type of artifacts, varied by location. A statistically significant positive relationship between the weights of artifacts and natural objects was observed, suggesting that they experience similar fates in the oceans. The major axis of the polystyrene foam in the Yonaguni area differed significantly from those in the Shimane, Tsushima, and Okinawa areas. The major axis in the Tsushima area significantly differed from those in all other studied areas. This study found the geological difference in the distribution and the major axis of polystyrene foams. These differences may be relevant to environmental physical factors (wind, rain, and waves), chemical alterations by ultraviolet rays, exposed time, the gyre, and local currents.

Using virtual fieldwork to support interprofessional and community-based learning: students from four faculties investigate life on a remote island in Japan

IntroductionThe Mishima Islands in Kagoshima Prefecture, Japan, are remote islands designated as medically underserved. Supporting the people living in such remote islands requires a multifaceted examination of the livelihoods of the residents, including their health, work, and living environment.MethodsStudents from the faculties of nursing, veterinary science, agriculture, and engineering participated in a 3-day virtual fieldwork session held synchronously from the campus of Kagoshima University and on a remote island in the Mishima Mura island group in Kagoshima Prefecture, Japan. Coursework and post-course surveys were analyzed to determine student engagement and learning. In particular, the analysis considered learning in relation to interprofessional learning and community-based learning.Results and discussionStudents expressed being able to conduct fieldwork online, collaborate with students from multiple faculties and graduate schools, and apply their expertise. These outcomes were reflected in the five-point Likert scale evaluation responses, highlighting a sense of accomplishment and satisfaction. Virtual fieldwork can contribute to student learning by introducing new concepts and allowing them to consider development issues in remote areas from multiple perspectives.

Hidden gems: Scattered knowledge hampered freshwater jellyfish research over the past one-and-a-half centuries.

Freshwater jellyfish (= limnic medusa-budding hydrozoans, FWJ) are a small group of cnidarians found on all continents except Antarctica in temperate to tropical latitudes. Members of this group belong primarily to three genera: Astrohydra, Craspedacusta, and Limnocnida. While Astrohydra and Limnocnida are typically restricted to the islands of Japan, Africa, and the Indian subcontinent, one species or potential species complex, Craspedacusta sowerbii, became globally invasive. Despite research going back about one-and-a-half centuries, little is known about their phylogeny and ecology compared to marine jellyfish. Recent species distribution modelling, however, showed that by 2050, C. sowerbii will potentially extend their distribution ranges due to global warming to high-latitude ecosystems and be present (medusa stage) for an extended time in the seasonal limnic production cycle. An increase in their relative ecological importance with temporal and spatial spreading is hypothesised. Only recently, it has been shown that the trophic roles of polyps and medusae and their prey overlap with other ecosystem members. In addition, medusa behaviour may cause trophic cascades and alter vertical nutrient distributions. However, polyps and other benthic life cycle stages are understudied. In globally, changing freshwater ecosystems that may become more accommodating for FWJ, an improved understanding of their population biology and ecosystem ecology is urgently needed. In this integrative review, we, therefore, explore reasons for the hampered historical research progress, contrast developments with those of marine cnidarians, compile and publish alongside an extensive and unprecedented literature database, and formulate avenues for future directions in FWJ research.

Integration of new zircon U–Pb ages with biostratigraphy to establish a high-precision age model of the Miocene Nakayama Formation on Sado Island in Central Japan

The most common age constraint for the diatomaceous sediments is biostratigraphy of siliceous microfossils. Although biostratigraphy is a powerful tool to establish stratigraphy and correlate with sedimentary sequences in other sites, biostratigraphy generally includes uncertainties difficult to evaluate. In this study, we measured zircon U–Pb ages of eight tuff beds intercalated with diatomaceous mudstone of the Nakayama Formation on Sado Island in Central Japan and integrated the U–Pb ages with diatom and radiolarian biostratigraphy, whose ages and errors were re-evaluated by this study, to establish an age model precisely representing the sedimentary age. Two tuff beds in the upper and middle part of the formation offered zircon U–Pb ages of 6.7 ± 0.2 Ma and 10.87 ± 0.07 Ma, which are consistent with biostratigraphy, and provided a good example of effective integration of zircon U–Pb ages with the biostratigraphy. On the other hand, zircon U–Pb ages of the other six tuff beds in the lower part are around 12 Ma and not distinguishable from each other. In addition, older zircon grains in the 6 tuff beds are assembled in the interval from 30 to 20 Ma, which is consistent with the age of the volcanic basement rocks forming most part of Sado Island. Similarities in chemical compositions of glass shards and age distributions of zircon grains indicate that the volcaniclastic components in the tuff beds should originate from single or associated magmatic activities.

The diversity of ants in moderately isolated islands of Japan: towards understanding of factors affecting their colonisation success

ABSTRACT How species diversity is determined is an old question in community ecology but is not yet well understood. Island biotas offer opportunities to address this issue. Here, the ant fauna was studied in five moderately isolated islands of Japan and compared with those in reference regions on the nearby main islands to assess whether ants’ ecological characteristics affect their island colonisation success. Species that were more abundant in the reference regions were more frequently found on the islands, suggesting that ant communities on these islands are likely to have a nested subset structure. Species inhabiting both forests and open lands tended to occur more frequently in the study islands at least than those exclusively inhabiting forests, but this difference was not significant. In addition, nest sites and worker body size did not have significant effects on their occurrence in these islands. These results seem to suggest that the study islands as a whole offer various environments that support a variety of ant species with different ecological characteristics. It is suggested in this study that island size affects the species richness, as has often been reported.

CAG Repeat Expansion in THAP11 Is Not Detected in a Cohort with Spinocerebellar Ataxia from Hokkaido, the Northernmost Island of Japan

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Reply to: “CAG Repeat Expansion in THAP11 is Not Detected in a Cohort with Spinocerebellar Ataxia from Hokkaido, the Northernmost Island of Japan”

Reply to: “<scp>CAG</scp> Repeat Expansion in <scp><i>THAP11</i></scp> is Not Detected in a Cohort with Spinocerebellar Ataxia from Hokkaido, the Northernmost Island of Japan”

Oceanitis abyssalis sp. nov., a new deep-sea fungus from sunken wood collected at the depth of 5707 m in the Northwest Pacific Ocean

A new deep-sea fungus, Oceanitis abyssalis sp. nov. was described based on analyses of the LSU rDNA sequences and morphological characteristics. The new species was found on a branch of Prunus sp. collected at 5707 m depth of the abyssal plain in the Northwest Pacific Ocean, east off the Japan Islands. To the best of our knowledge, our discovery is the deepest record of the genus Oceanitis and also for the obligate deep-sea fungi. Morphologically, Oceanitis abyssalis is closely similar to O. scuticella Kohlmeyer and both were collected from deep-sea water. Oceanitis abyssalis can be distinguished from O. scuticella by having unicellular ascospores, smaller deciduous polar appendages and occasionally tree-like appendages, semi-persistent asci, smaller ascomata that are drop-shaped, and cream-colored. We also reviewed the taxonomic status of O. scuticella. The phylogenetic position of the authentic O. scuticella remains unclear due to the lack of genetic information and the inaccessibility of the type specimen. However, our investigation of the molecular and morphological characteristics of specimens previously identified as O. scuticella suggests that they include several cryptic, undescribed species. Notably, the Kuril-Kamchatka Trench material (M0229768), previously identified as O. scuticella, is suggested to be a representative of Oceanitis abyssalis.

Distributions of exotic herbaceous species along a roadside on Chichijima, the Ogasawara Islands, and their relationship with human disturbance

AbstractOceanic islands are a major tourist destination, and the invasion of exotic plants on oceanic islands is a serious problem. To discuss how exotic herbaceous plant invasion is driven by human disturbance on an oceanic island, we assessed the distribution patterns of exotic herbaceous species along a metropolitan road, including parking lots, on the island of Chichijima in the Ogasawara Islands of Japan in the North Pacific Ocean. We observed 16 exotic herbaceous species representing seven families, and all the species have also been recorded in surveys 25 years ago. Species richness (number of species per plot) ranged from 0 to 9 with an average of 2.49. Distance from a parking lot was significantly negatively related to the distribution patterns of seven species and positively related to three species, pointing to parking lots being critical nodes along the dispersal pathways of exotic herbaceous species in Chichijima. Although roads are well known to play an important role as corridors for the invasion and seed dispersal of exotic plants, our results suggest that it would also be important to consider the location of parking lots to understand the distribution of exotic herbaceous species in road networks. We suggest that intensive weed management near parking lots and car wash protocols on Chichijima may be effective in halting exotic species spread.

Age-Related Changes in the Body Size and Weight of Sika Deer (Cervus nippon): A Comparison between Northern and Southern Populations of Honshu, The Main Island of Japan

Age-Related Changes in the Body Size and Weight of Sika Deer (Cervus nippon): A Comparison between Northern and Southern Populations of Honshu, The Main Island of Japan

A record of the northernmost location of Otus elegans in the Pacific area

This individual of Otus elgans was rescued on Udo Island located in the east of Jeju Island, the southernmost part of the Korean Peninsula, on January 4, 2007. It was found at 3° 32″ N, 2° 58′ E, which is the northernmost record among the habitats of Otus elegans. After that, we took photographs of its shape, recorded its calls, and analyzed them. While analyzing we confirmed that it is an unrecorded species in Korea. We classified the chick calls based on structural similarity on spectrograms (view range: 0–7.5 kHz; window length: 1 second). We measured it and the results are; weight: 86.7 g, total length: 210 mm, wing length: 170 mm, tail length: 68.0 mm, and Tarsus length: 25.13 mm. In addition, its vocalizations are structurally diverse: duration, ∼10 ms to 1.5 s; peak frequency (adults), <900 to >3000 Hz. Currently, it was found not only on Nansei Shoto, Minami-daito-jima, and Okino Islands in Japan but also on the Batanes Islands in eastern China and the Babuyan Islands. Moreover, assumed that it inhabits Okinoshima, lying beyond the known northern limit of distribution. Therefore, this study record demonstrates the attempt of O. elegans to move north even to Udo Island from the previous habitats.

A New Record of Bufo gargarizans Complex (Bufonidae, Anura) from Truong Son Mounts, Ha Tinh and Ha Giang Provinces, Vietnam Based on Molecular Evidence with a Description of a New Species

Based on a combination of molecular and morphological data, we herein report a new species within the bufonid Bufo gargarizans species complex. This is a widespread species complex with distribution from eastern Russia and the Korean Peninsula to China and the Ryukyu Islands of Japan. Records of this species have been documented in the Guangxi and Yunnan Provinces near the border with Vietnam and, for the first time from Vietnam, in Ha Giang Province. The new record of Bufo cf. gargarizans from Vietnam is from Ha Tinh Province. This species has never been reported from Vietnam so far south, about 550 km south from the previously known locality in Ha Giang Province. The female specimen was found in the Ha Tinh Province, Vu Quang National Park of central Vietnam and two specimens (male and female) were found Ha Giang Province. They are clearly distinguished from B. gargarizans and all the mentioned species by a specific color pattern on the belly and creamy-yellowish throat with large, bright red speckles. Genetic divergences of three Vietnam specimens from Ha Giang and Ha Tinh Provinces in the ND2 gene sequences between the В. sp. nov. and all other congeners ranged from 4.3% (with B. andrewsi) to 7.0% (with B. stejnegeri). We give a description of the morphological characters and coloration of the new record and provide an expanded diagnosis.

Knowledge and practical skills for cancer pain management among nurses on remote islands in Japan and related factors nationwide.

To clarify the knowledge and practical skills needed for cancer pain management among nurses on remote islands in Japan and related factors nationwide. Due to geographical factors, nurses working on remote islands in Japan have few opportunities to attend training programs, which makes it difficult to acquire the knowledge and practical skills needed to provide pain management for patients with cancer. We conducted a self-administered questionnaire survey regarding knowledge and practical skills in pain management for patients with cancer. Cross-sectional study. Nurses working in cancer pain care in medical facilities and home care on remote islands throughout Japan. We analysed 128 responses. Regarding knowledge, the average accuracy level was 49.1%. Items with a low accuracy rate included selecting medicine according to the type of pain and the patient's condition. Regarding practice, the items with low scores included analgesics appropriate for the type of pain and relating physical pain to mental, social and spiritual aspects. The most common significant factor in both knowledge and practice was related to postgraduate training. These findings suggest that to improve the knowledge and practical skills for cancer pain management among nurses on remote islands in Japan, it is necessary to incorporate clinical reasoning into basic education and establish remote education systems and consultation systems with other facilities.

Biopsychosocial Consideration of Ikigai in Older Adults in Japan through a Cross-Sectional Study.

Ikigai-a Japanese concept that includes elements such as life's purpose and meaning-has been reported to be associated with various systemic health conditions, such as the risk of developing physical dysfunction or death in older adults. However, there are no reports that comprehensively examine the psychological and social aspects of Ikigai. We attempted to clarify the characteristics of Ikigai by examining it from a biopsychosocial model using physical, psychological, and social perspectives through a cross-sectional study on sarcopenia, frailty and healthy life expectancy in a hilly and mountainous area of Japan. Koyadaira in Mima City, which is located in a hilly and mountainous region on Shikoku Island in Japan, was targeted. This cross-sectional study included 105 outpatients aged 65 and over, with an average age of 79.02 ± 6.91 years. Ikigai (self-rating score on a scale of 0 (no Ikigai) to 5 (the highest Ikigai)) participants' level of physical activity (the Physical Activity Scale for the Elderly, PASE), degree of depression (the Geriatric Depression-15 Scale, GDS-15), cognitive function (the Mini-Mental State Examination, MMSE) and social isolation (the abbreviated Lubben Social Network Scale, LSNS-6) was assessed. Significant positive correlations were found between PASE and MMSE. The LSNS-6 significantly correlated with the MMSE and GDS-15. In a path model, out of four paths from PASE, GDS-15, MMSE, and LSNS-6 to Ikigai, the path from the GDS-15 alone was significant (correlation coefficient -0.271, p < 0.01). The adaptability of this model was good. This study indicates that depressive status has a large impact on Ikigai, along with physical, cognitive, and social conditions; thus, it is appropriate to consider that an affective psychological status, such as depressive symptoms, is a fundamental condition for having Ikigai.

Far-East Asian Toxoplasma isolates share ancestry with North and South/Central American recombinant lineages.

Toxoplasma gondii is a global protozoan pathogen. Clonal lineages predominate in Europe, North America, Africa, and China, whereas highly recombinant parasites are endemic in South/Central America. Far East Asian T. gondii isolates are not included in current global population genetic structure analyses at WGS resolution. Here we report a genome-wide population study that compared eight Japanese and two Chinese isolates against representative worldwide T. gondii genomes using POPSICLE, a novel population structure analyzing software. Also included were 7 genomes resurrected from non-viable isolates by target enrichment sequencing. Visualization of the genome structure by POPSICLE shows a mixture of Chinese haplogroup (HG) 13 haploblocks introgressed within the genomes of Japanese HG2 and North American HG12. Furthermore, two ancestral lineages were identified in the Japanese strains; one lineage shares a common ancestor with HG11 found in both Japanese strains and North American HG12. The other ancestral lineage, found in T. gondii isolates from a small island in Japan, is admixed with genetically diversified South/Central American strains. Taken together, this study suggests multiple ancestral links between Far East Asian and American T. gondii strains and provides insight into the transmission history of this cosmopolitan organism.

Traditional Meiyu-Baiu has been suspended by global warming.

More than 1000 years, the Meiyu-Baiu have shaped the uniqueness of natural resources, civilization and culture in the Yangtze River Basin of China and the main islands of Japan. In recent decades, frequent rainstorms and droughts have seemingly diminished the misty features of traditional Meiyu-Baiu rainfall. However, there is still no consensus on whether their traditional nature is suspended. In this study, we quantitatively demonstrate that the Meiyu-Baiu almost completely lost their traditional features during 1961-2023, ∼80% of which can be attributed to anthropogenic warming. Furthermore, in a warmer future, the traditional Meiyu-Baiu will be more unlikely to appear. This study underscores the urgency in adapting to climate shift because destructive extremes are measurably taking the place of mild and maternal rains.