Mainland Of Japan Research Articles

Summer collection of multiple southern species of ticks in a remote northern island in Japan and literature review of the distribution and avian hosts of ticks.

Expansion of ticks and tick-borne diseases is of increasing concern worldwide. To decrease the risk of ticks and tick-borne diseases to public health, understanding the mechanisms of their current distribution and future expansion is needed. Although tick distribution has been studied globally on continents and large islands that are inhabited by large mammals, less attention has been paid to remote islands. However, small islands are often important stopover sites for migratory birds that may contribute to long-distance dispersal of ticks. Therefore, islands would be a suitable system to rule out potential effects of mammals and to evaluate the contribution of birds to the expansion of ticks and tick-borne diseases. We collected questing ticks by dragging cloths over vegetation on Tobishima Island, northern Japan, in summer 2021, and conducted a literature search of the distribution and avian hosts of hard tick. We found several southern species of ticks (Haemaphysalis hystricis, H. formosensis, H. cornigera, Amblyomma testudinarium, and Dermacentor bellulus) on the island. These species have rarely or never been reported from the mainland of Japan at similar latitudes or higher, where large mammals are found. They are known vectors of tick-borne diseases, such as severe fever with thrombocytopenia syndrome. The present study suggests that migratory birds may contribute to the expansion of ticks and tick-borne diseases, and a remote island may function as a front line and/or a hub for their expansion. Evaluating tick fauna on remote islands used by migratory birds might be useful to monitor the expansion.

Association Between Nursing Discussions, Resilience, Workplace Social Support and Burnout: A Quantitative Study in Japan.

Although it is known that resilience is negatively associated with burnout, and that certain interventions can effectively increase resilience, little is known about online resilience-enhancing interventions during the COVID-19 crisis. The aim of this study was to identify the association between an online resilience-enhancing intervention and workplace social support, and burnout among nurses working in the mainland and remote islands of Japan during the COVID-19 crisis. Pretest-posttest was conducted between April 2020 and February 2021, and the questionnaire survey included the bidimensional resilience scale, the Japanese version of Pine's Burnout Measure, and the workplace social support scale. Changes in burnout, resilience, and social support and the associations with nursing discussions as intervention were analyzed. Participants were 98 Nurses with 1 to 10 years of experience from Japan's mainland and remote island hospitals of Kagoshima Prefecture participated in a baseline survey in April 2020. Of these, 76 participated in a secondary survey in September 2020, and 69 participated in the intervention program and a third survey in February 2021. The online intervention over Zoom consisted of small-group nursing discussions based on the broaden-and-build theory. Changes in burnout showed a significant negative association with change in workplace social support (Coef. = -0.019, 95% CI -0.035- -0.003), as did the interaction between change in acquired resilience and intervention (Coef. = -0.088, 95% CI -0.164- -0.011). Change in workplace social support was significantly negatively associated with changes in burnout, as was the interaction of intervention and acquired resilience. Promotion of this intervention and making workplace social support more accessible may contribute to reduce burnout in nurses.

Geological record of 18th and 19th century tsunamis along the Japan Sea coast of Tsugaru Peninsula, northwestern Japan

Our stratigraphic and paleontological investigations revealed three sandy event deposits (E1, E2, and E3) within peaty clay at the Sotomeyachi site on the Japan Sea coast of Honshu (mainland of Japan), northwestern Japan. Visual examination and X-ray computed tomographic images of samples of the deposits provided evidence of strong currents characterized by rip-up mud clasts, load casts, and erosional lower stratigraphic contacts. Marine, brackish, and freshwater diatom species in the deposits indicate they were derived from various coastal sources. Radiocarbon dating constrained the ages of event deposit E2 to 1764–1902 CE and E3 to 1558–1845 CE, 1699–1918 CE, and 1704–1781 CE. According to historical records, the E2 deposits likely correspond to the tsunami generated by the 1833 Shonai-oki earthquake, and the E3 deposits correspond to a tsunami associated with either a submarine landslide associated with the 1741 Oshima-Oshima eruption or the 1793 Nishi-Tsugaru earthquake. Because our numerical simulation of the 1741 tsunami showed no significant inundation at the study site, it is more likely that the 1793 earthquake was responsible for tsunami deposit E3. The E1 deposit is discontinuous and showed different characteristics (absence of load structures, rip-up mud clasts and mixed diatom assemblages) to those of events E2 and E3, so it is unlikely to be a tsunami deposit.

Interagency discrepancies in tropical cyclone intensity estimates over the western North Pacific in recent years

AbstractThis study investigates interagency discrepancies among best‐track estimates of tropical cyclone (TC) intensity in the western North Pacific, provided by the Joint Typhoon Warning Center (JTWC), the China Meteorological Administration (CMA), and the Regional Specialized Meteorological Center (RSMC) Tokyo during 2013 to 2019. The results reveal evident differences in maximum wind speed (MSW) estimates, where linear systematic differences are significant. However, the Dvorak parameter (CI) numbers derived from the MSWs reported by the three agencies are internally consistent. Further analysis suggests that the remained CI discrepancies are related to differences in the estimation of intensity trends, initial intensities, and TC positions among these datasets. In addition, the CI estimates provided by the JTWC for TCs over the open ocean are generally higher than those reported by the CMA and RSMC. However, the estimates from CMA and RSMC tend to give higher TC intensities for the TCs in the mainland and coastal areas of China and Japan, respectively, than those over the open ocean with the same intensity in JTWC dataset. This pattern potentially reflects the extensive use of surface observations by these two agencies for landfalling and offshore TCs. These results may help the research community to get more accurate details about the TCs in WNP from the best track datasets of different agencies.

Cascading effects of the Changbai Mountains on an extreme weather disaster in northern Japan in January 2021

A sequence of a snowstorm, a quasi-stationary convergence zone (Japan Sea polar airmass convergence zone, JPCZ) and a mesoscale coastal front (MCF) caused an extreme weather disaster along the Sea of Japan (SOJ) coast in northern Japan from January 7 to 11, 2021. To examine how the presence of the Changbai Mountains (CMs) affects these multi-scale successive phenomena, we conducted numerical simulations with and without modified topography of the CMs and their surrounding regions using a regional atmospheric model with a horizontal resolution of 4 km. Backward-trajectory analyses and an additional experiment that removed the sublimation process of snow were also performed to clarify the formation and maintenance processes of the MCF. The CMs lead to the structural change of the snowstorm developing over the SOJ, enhancement of the JPCZ, and formation of the MCF, affecting heavy snowfall in the SOJ coastal areas. The MCF, which is a mesoscale phenomenon smaller than the JPCZ, is formed and maintained by the monsoonal flows that detour from the north and south of the CMs. Several of the parcels that detour from north of the CMs intrude into the MCF through the boundary layer, which is thermodynamically modified by the heat and moisture supply from the sea, whereas the inland flows that penetrate the MCF from its south are composed of two major routes: one is the flow detouring from south of the CMs that crosses the high mountains on the mainland of Japan, and the other is the parcels detouring from north of the CMs that penetrate from the inland after they land on the northern coast. The difference in equivalent potential temperature between the inland flows and the monsoonal flow from the sea is responsible for the MCF formation. A cold pool near the surface also contributes to the prolonged MCF. Understanding of the CMs’ cascading effects on multi-scale phenomena from synoptic scale to mesoscale is necessary for the prediction of extreme weather disasters over Japan in winter.

Multiple introductions of SARS-CoV-2 B.1.1.214 lineages from mainland Japan preceded the third wave of the COVID-19 epidemic in Hokkaido

BackgroundThe third wave of the COVID-19 epidemic in the island of Hokkaido, the second largest island in Japan, began abruptly in October 2020. MethodsWe conducted a phylodynamic analysis of the SARS-CoV-2 genome sequences obtained from tertiary medical centers in the Greater Tokyo Area and Sapporo, the largest city in the island of Hokkaido, and genome sequences published by GISAID, an international SARS-CoV-2 genome database. We also analyzed the statistics on the person-nights of travelers in the island of Hokkaido from the Greater Tokyo Area in 2019 versus 2020. ResultsAt least eight sub-lineages belonging to the B.1.1.214 lineage were introduced to the island of Hokkaido from the island of Honshu, the mainland of Japan from late July to November 2020, during the governmental travel promotion program. Five of the eight sub-lineages originated from the Greater Tokyo Area. Comparison of the monthly ratios of the person-nights of travelers in the island of Hokkaido from the Greater Tokyo Area in 2019 and 2020 revealed that the highest value occurred in October 2020. ConclusionWe contend that the Japanese governmental travel promotion program contributed to the introduction of the B.1.1.214 sub-lineages from the main island of Honshu to the island of Hokkaido, and drove the third wave in Hokkaido, even if we are unable to establish the causality.

Estimation of water origins within an explosive cyclone over the Sea of Japan using an isotopic regional spectral model

AbstractMoisture sources and their corresponding temperature and humidity are important for explosive extratropical cyclones’ development regarding latent heating. To clarify the water origins and moisture-transport processes within an explosive cyclone, we simulated an explosive cyclone migrating poleward across the Sea of Japan on November 30, 2014, by using an isotopic regional spectral model. In the cyclone’s center area, a replacement of water origins occurred during the cyclone’s development. During the early stage, the warm conveyor belt (WCB) transported large amounts of moisture from the East China Sea and Kuroshio into the cyclone’s inner region. While in the deepening stage, the cold conveyor belt (CCB) and dry intrusion (DI) conveyed more moisture from the Northwest Pacific Ocean and the Sea of Japan, respectively. Compared with the contribution of local moisture, that of remote moisture was dominant in the cyclone’s center area. Regarding the water origins of condensation within the frontal system in the deepening stage, the Northwest Pacific Ocean vapors, principally transported by the CCB, contributed 35.5% of the condensation in the western warm front. The East China Sea and Kuroshio moisture, conveyed by the WCB, accounted for 32.4% of the condensation in the cold and eastern warm fronts. In addition, condensation from the Sea of Japan, which was mainly triggered by the DI and induced by the topography, occurred on the west coast of the mainland of Japan and near the cyclone center. The spatial distribution of the isotopic composition in condensation and water vapor also supports the water-origin results.

Genetic characteristics of the amphidromous fish Ayu Plecoglossus altivelis altivelis (Osmeriformes: Plecoglossidae) on Yaku-shima Island in Japan, the southernmost population of the subspecies.

The Ayu (Plecoglossus altivelis altivelis) population on Yaku-shima Island, Kagoshima Prefecture, Japan represents the southernmost population of the subspecies and is considered to be facing extinction. We investigated the genetic characteristics of Ayu in the Miyanoura River (MYU) in the northeast of the island and the Kurio River (KRO) in the southwest of the island, using partial sequences of mitochondrial (mt) control region and polymorphic microsatellite (simple sequence repeat: SSR) loci. The mtDNA analysis revealed that the Yaku-shima Island population was significantly differentiated from other Ayu populations; additionally, the MYU and KRO populations were significantly different from each other in terms of mtDNA (pairwise ΦST = 0.5826, P < 0.01) and SSR (pairwise ΦST = 0.1598, P < 0.01) analyses, indicating very little or no gene flow between them. The mtDNA haplotype diversity values were minimal for KRO and somewhat lower for MYU (h = 0.8176) than for each population from the mainland of Japan (Honshu-Kyushu) and the Korean Peninsula (h = 0.9905-1.0000). The mean values of expected heterozygosity (He) of SSRs were also lower in KRO (mean He = 0.555) than in MYU (mean He = 0.649). A considerably small effective population size (Ne = 100.1 for MYU, 151.2 for KRO) and a bottleneck effect for Yaku-shima Island population were suggested by SSR analysis. These findings underscore the importance of monitoring the genetic diversity of Ayu on Yaku-shima Island and the necessity of designing conservation policies for each river's population.

Ecological Traits of a Common Japanese Pit Viper, the Mamushi (Gloydius blomhoffii), in Kyoto, with a Brief Geographic Comparison

Gloydius blomhoffii is a common pitviper distributed throughout Japan except for Okinawa Prefecture. To understand intraspecific geographic variation of this widely distributed snake, I describe several of its basic ecological traits observed during a 31-year-field survey conducted in the forest of Ashiu, northeastern Kyoto, in the western region of the mainland of Japan, and compare these traits with those reported in previous studies conducted in widespread areas of Japan. Body length of G. blomhoffii in Kyoto was smaller than that in the northernmost range and larger than that in the southernmost range. Sexual size dimorphism in snout-vent length, tail length, and body mass showed the same trends as in other areas. The sex ratio of the collected snakes was biased to females, which has not been observed in other studies. Pregnant females showed higher body temperature than males and non-pregnant females at a given air temperature. Parturition period, litter size, and body size of neonates generally overlapped with those reported in previous studies. Stomach contents were found only in 9.1% of snakes and consisted of rodents, frogs, and newts, which are prey items already known in G. blomhoffii. Although the forest in Ashiu has been incurred drastic environmental degradation, no obvious change in body size was detected over the study period. This study adds information on ecological traits of G. blomhoffii based on a population-level study and will facilitate future intensive field research to understand this common, but still poorly investigated, venomous snake endemic to Japan.

Multiple waves of freshwater colonization of the three-spined stickleback in the Japanese Archipelago

BackgroundThe three-spined stickleback (Gasterosteus aculeatus) is a remarkable system to study the genetic mechanisms underlying parallel evolution during the transition from marine to freshwater habitats. Although the majority of previous studies on the parallel evolution of sticklebacks have mainly focused on postglacial freshwater populations in the Pacific Northwest of North America and northern Europe, we recently use Japanese stickleback populations for investigating shared and unique features of adaptation and speciation between geographically distant populations. However, we currently lack a comprehensive phylogeny of the Japanese three-spined sticklebacks, despite the fact that a good phylogeny is essential for any evolutionary and ecological studies. Here, we conducted a phylogenomic analysis of the three-spined stickleback in the Japanese Archipelago.ResultsWe found that freshwater colonization occurred in multiple waves, each of which may reflect different interglacial isolations. Some of the oldest freshwater populations from the central regions of the mainland of Japan (hariyo populations) were estimated to colonize freshwater approximately 170,000 years ago. The next wave of colonization likely occurred approximately 100,000 years ago. The inferred origins of several human-introduced populations showed that introduction occurred mainly from nearby habitats. We also found a new habitat of the three-spined stickleback sympatric with the Japan Sea stickleback (Gasterosteus nipponicus).ConclusionsThese Japanese stickleback systems differ from those in the Pacific Northwest of North America and northern Europe in terms of divergence time and history. Stickleback populations in the Japanese Archipelago offer valuable opportunities to study diverse evolutionary processes in historical and contemporary timescales.

Accumulation of Deleterious Mutations in Landlocked Threespine Stickleback Populations.

Colonization of new habitats often reduces population sizes and may result in the accumulation of deleterious mutations by genetic drift. Compared with the genomic basis for adaptation to new environments, genome-wide analysis of deleterious mutations in isolated populations remains limited. In the present study, we investigated the accumulation of deleterious mutations in five endangered freshwater populations of threespine stickleback (Gasterosteus aculeatus) in the central part of the mainland of Japan. Using whole-genome resequencing data, we first conducted phylogenomic analysis and confirmed at least two independent freshwater colonization events in the central mainland from ancestral marine ecotypes. Next, analyses of single nucleotide polymorphisms showed a substantial reduction of heterozygosity in freshwater populations compared with marine populations. Reduction in heterozygosity was more apparent at the center of each chromosome than the peripheries and on X chromosomes compared with autosomes. Third, bioinformatic analysis of deleterious mutations showed increased accumulation of putatively deleterious mutations in the landlocked freshwater populations compared with marine populations. For the majority of populations examined, the frequencies of putatively deleterious mutations were higher on X chromosomes than on autosomes. The interpopulation comparison indicated that the majority of putatively deleterious mutations may have accumulated independently. Thus, whole-genome resequencing of endangered populations can help to estimate the accumulation of deleterious mutations and inform us of which populations are the most severely endangered. Furthermore, analysis of variation among chromosomes can give insights into whether any particular chromosomes are likely to accumulate deleterious mutations.

Phylogenetic analyses reveal that simian foamy virus isolated from Japanese Yakushima macaques (Macaca fuscata yakui) is distinct from most of Japanese Hondo macaques (Macaca fuscata fuscata)

Japanese macaque (Macaca fuscata) is an indigenous Old World monkey (OWM) species that inhabits the Japanese archipelago. There are two subspecies of Japanese macaque: Yakushima macaque (M. f. yakui) which inhabits Yakushima Island exclusively, and Hondo macaque (M. f. fuscata) which inhabits the mainland of Japan. Yakushima macaque is considered to be branched off from a certain parental macaque group that had inhabited the mainland of Japan. However, the process of sub-speciation of the Yakushima macaque is still unclear at present. In this study, to gain new insight into the process of sub-speciation of Japanese macaque, we utilized the simian foamy virus (SFV) as a marker. SFVs are found in virtually all primates except humans and undergo species-specific cospeciation with the hosts. The phylogenetic analysis of conserved regions of the env gene in SFVs remarkably resembled that of the OWMs with high statistical confidence. The phylogenetic analyses also indicated that there are four (1–4) genotypes among Asian OWMs investigated. SFVs derived from Asian OWMs except Yakushima macaque were classified as genotypes 1–3, whereas SFVs isolated from all Yakushima macaques and one Hondo macaque were classified as genotype 4. Interestingly, genotype 4 was firstly branched off from the rest of the genotypes, which might indicate that the macaques infected with genotype 4 SFV were derived from the “older” population of Japanese macaques. The high prevalence of genotype 4 SFVs among Yakushima macaque might reflect the possibility that they are a descendant of the population settled earlier, which has been geographically isolated in Yakushima Island.

Real-time quantification of the total HO2 reactivity of ambient air and HO2 uptake kinetics onto ambient aerosols in Kyoto (Japan)

HO2 radicals play important roles in tropospheric chemistry. The large discrepancies among field measurements and sophisticated model predictions for the overall HO2 concentrations can be attributed to the HO2 uptake coefficients onto ambient aerosols (γ) have not yet been properly quantified. This study presents the first online measurement of the total HO2 reactivity caused by the ambient gas phase (kg') and aerosol phase (ka') in the summer of 2018 in Kyoto, Japan, using a combined laser-flash photolysis and laser-induced fluorescence (LFP–LIF) technique coupled with a versatile aerosol concentration enrichment system (VACES) that enriches ambient aerosols. The results denote that kg' ranged from 0.1 s−1 (25th percentile) to 0.32 s−1 (75th percentile) with an average value of 0.22 ± 0.16 s−1 (1σ), which can be primarily explained by the reaction of HO2 with NO2. With the application of VACES and the auto-switching aerosol filter, ka' ranged from 0.004 s−1 (25th percentile) to 0.028 s−1 (75th percentile) with an average value of 0.017 ± 0.015 s−1. When converted ka' to ambient conditions (by dividing with the enrichment factor), this result was ~10 times higher than the HO2 reactivity caused by its self-reaction under ambient concentration levels (~5 ppt) at 298 K. The related γ ranged from 0.08 (25th percentile) to 0.36 (75th percentile), with an average value of 0.24, which is comparable with the values used in previous modeling studies (~0.2); however, it presents a large variation of ±0.20 (1σ) within the measurement time. This indicates that a large bias may exist with respect to the estimation of HO2 concentrations when using a constant γ value. Further, we suggest that different γ values should be applied in modeling studies depending on the environment conditions; the γ value obtained here can be used as an upper limit value for urban areas in the summer due to possible aerosol phase changes. The analysis of ambient air backward trajectories indicates that the predominant NO2 emission sources originated from the mainland of Japan. However, no significant differences regarding HO2 uptake coefficients were observed when air masses came through the mainland or from the coastal direction. This study provides considerably reliable γ, which could increase the modeling accuracy of heterogeneous processes in tropospheric chemistry. However, combining online and offline methods appears to be more suitable for addressing the variation in γ and model discrepancies in further studies.

A review of the stink bug genus Plautia Stål from Japan (Hemiptera, Heteroptera, Pentatomidae).

In this review, we revise the pentatomine stink bug genus Plautia Stål from Japan. Five species are recognized and diagnosed, including three new species: P. sakishimensis sp. nov., P. himechabane sp. nov., and P. ishigaki sp. nov. One of these, P. himechabane sp. nov., was previously regarded as P. splendens Distant for the populations of the mainland of Japan, the Ryukyu Islands, and China. The species Plautia cyanoviridis Ruckes is proposed as a junior synonym of P. splendens, which is endemic to the Ogasawara Islands. A key is provided to facilitate the identification of the five species known in Japan.

Redescription and new records of a poorly known leucosiid crab,Pseudophilyra punctulata Chen Ng, 2003, and description of a new species of Pseudophilyra from Japan (Crustacea: Decapoda: Brachyura).

A poorly known leucosiid crab, Pseudophilyra punctulata Chen Ng, 2003, originally described on the basis of an immature male holotype and an immature female paratype from Singapore, is rediscovered and rediagnosed on the basis of material from Thailand, the Philippines and the Ryukyu Islands (Japan). In addition, a new species closely related to P. punctulata, P. parilis, is described and illustrated on the basis of material from Mie Prefecture, Honshu mainland of Japan. The new species is distinguished from P. punctulata by the coarser granules bordering the lateral carapace margins and the different shape of the gonopods. Pseudophilyra tridentata Miers, 1879, is also compared with P. punctulata and P. parilis n. sp. because of the close similarities in the overall morphology of the carapace and appendages, but can easily be differentiated by the smoother carapace and thoracic sternum surface, different shape of the carapace and the stouter cheliped palm. It is possible that previous records of P. tridentata outside Japan might contain more than one species.

Human T-cell leukemia virus type I Tax genotype analysis in Okinawa, the southernmost and remotest islands of Japan: Different distributions compared with mainland Japan and the potential value for the prognosis of aggressive adult T-cell leukemia/lymphoma

Okinawa, comprising remote islands off the mainland of Japan, is an endemic area of human T-cell leukemia virus type I (HTLV-1), the causative virus of adult T-cell leukemia-lymphoma (ATL) and HTLV-1-associated myelopathy (HAM). We investigated the tax genotype of HTLV-1 among 29 HTLV-1 carriers, 74 ATL patients, and 33 HAM patients in Okinawa. The genotype distribution—60 (44%) taxA cases and 76 (56%) taxB cases—differed from that of a previous report from Kagoshima Prefecture in mainland Japan (taxA, 10%; taxB, 90%). A comparison of the clinical outcomes of 45 patients (taxA, 14; taxB, 31) with aggressive ATL revealed that the overall response and 1-year overall survival rates for taxA (50% and 35%, respectively) were lower than those for taxB (71% and 49%, respectively). In a multivariate analysis of two prognostic indices for aggressive ATL, Japan Clinical Oncology Group-Prognostic Index and Prognostic Index for acute and lymphoma ATL, with respect to age, performance status, corrected calcium, soluble interleukin-2 receptor, and tax genotype, the estimated hazard ratio of taxA compared with taxB was 2.68 (95% confidence interval, 0.87–8.25; P=0.086). Our results suggest that the tax genotype has clinical value as a prognostic factor for aggressive ATL.

Real Interest Rate Parity in the Northeast Asian Countries: Evidence from the Quantile Unit Root Test

The main purpose of examining real interest rate parity (RIRP), focus on explore more evidence from the quantile unit root test. This study applies the Quantile unit root test to assess the validity of the RIRP for Northeast Asian countries (including Russia, Mongolia, Mainland of China, South Korea and Japan) relative to the USA. In this paper, I examine the validity of RIRP from the nonlinear point of view and evidence obviously indicates that RIRP holds true for two countries. It implies that the operations and effectiveness of the monetary policies in these countries will be highly influenced by the exterior factors originating from the USA. At the same time, my results point out their real interest rate convergence relative to the USA is mean reversion towards RIRP equilibrium values in a nonlinear way.The time series of all the countries from ADF and PP tests are non-stationary. By contrast, the KPSS tests with constant reject the stationary for all countries. According to QKS, RIRP of Japan and Russia are affected by USA. Meanwhile, China, South Korea and Mongolia do not support RIRP. Furthermore, central bank of China, South Korea and Mongolia could be pursue their independent monetary policies means that central bank does not follow market mechanism.In this paper focus on those countries that uses the macroeconomic variables includes consumer price index (CPI), inflation rate (INF), nominal interest rate (NIR), real interest rate (RIR) and real interest rate parity (RIRP). The data are collected at monthly started period for these countries are different cause the data availability, and the end of the sample is 2015M12 for all countries.

The Alternative Chinatown: Lewchew (Ryukyu) Kume Village and “36 Min Families” (另類唐人街 -「閩人三十六姓」與琉球久米村)

Kumemura Village, or Kuninda, has been known as the community of Chinese immigrants with a more than five-hundred year background of scholar-bureaucrat aristocracy in Lewchew, or Ryukyu. They supposedly originated from a group of 36 families from the Southern Chinese Min (閩) ethnic group since 1392. Although much research has been conducted on the subject matter throughout the years, there is almost no scholar who would tackle it on the concept of a “Chinatown.” There are basically two reasons to account for such tendency in academics. Firstly, unlike most Chinese immigrant groups in other parts of the world, the 36 Min Families who had moved to Lewchew did not leave the country of their own accord, for neither private nor economic reasons, but in fact, were ordered by Emperor Hongwu to emigrate for political reasons. Furthermore, Kuninda-chu, the descendants of 36 Min Families, have almost, in the same way as other Okinawa people regard them over the years, never seen themselves as “overseas Chinese.”However, this paper argues that there are still plenty of similarities between Kuninda-chu and other overseas Chinese in the world. The two main points for this paper are: firstly, Kuninda-chu relied excessively on the Chinese World Order and tributary system for its maintenance, so its survival rested primarily on the existence of this political structure, and was eventually disintegrated upon the collapse of the system. Secondly, Chinese culture was largely brought by Kuninda-chu to Ryukyu during the Ming and Qing Dynasties, but it is still kept alive and observed in Okinawa society to this day and in stark contrast with the Yamaonchu, the Japanese in the mainland of Japan, it directly helped shaping and forming the Okinawa people’s self-identity as Uchinan-chu.Truly, Kuninda no longer exists in the Okinawa society today, but Kuninda-chu’s descendants have been upholding their unique ethic image through various traditional activities organized by different groups, Kume-Sosekai notwithstanding. Moreover, Kuninda-chu is also one of the earliest overseas Chinese groups who had assimilated successfully into the local Okinawa community. It is clear that Kuninda is one of the most paramount alternative cases for the studies of overseas Chinese.過去有關琉球「久米村」的歷史研究，鮮有學者以「唐人街」的概念來探討它的歷史與社會形態。其原因係「久米村人」或稱「閩人三十六姓」擁有有別於一般認知的華僑特徵。其一、儘管「久米村人」來自於中國著名僑鄉福建，然而這些移民最初並非個人的意志，亦非家庭因素而來到琉球，因爲他們是「官派」移民。其二、早期第一代閩僑「出外」的目的，乃以經濟為主要誘因，然「閩人三十六姓」則是受明太祖洪武帝派遣，前來琉球以輔助王國之營運及維繫與中國的關係，其政治目的十分清晰。其三、「閩人三十六姓」的子孫之間幾乎不存在「華僑」意識，更多的視自己為琉球人的一部分，而其他琉球人亦如此視之。然而本文認爲「久米村人」與一般認知上的華僑、華人還是有許多共通之處。本文聚焦兩個主要面向，來探討「久米村」及「久米村人」在僑居地琉球的變遷與影響。兩大論點包括一、儘管「久米村」對琉球王國的發展功不可沒，然而過於仰賴「中華世界體系」的存在，故因該體制的興起而生，亦因該體制的衰亡而瓦解；二、「久米村人」是將中國文化大量帶進琉球的重要推手，中國文化至今仍在沖繩社會傳承，並在沖繩人形塑自我認同上發揮不可或缺的重要影響。儘管「久米村」已不復存在，然而擁有500年歷史的「久米村」留下了龐大有跡可尋的歷史紀錄，而「久米村人」的後裔至今仍透過許多聯誼組織，低調地繼續維繫著在琉球社會中獨特族群的形象，而「久米村人」也是歷史上華僑最早「落地生根」的族群之一，提供了華僑、華人研究不可多得的重要個案。 (This article is in Chinese.)

Differential susceptibility to the tracheal mite Acarapis woodi between Apis cerana and Apis mellifera

In Japanese honey bees Apis cerana japonica, infestations of the tracheal mite Acarapis woodi have spread rapidly over the mainland of Japan, causing damage and the collapse of colonies. Meanwhile, infestations by mites in Apis mellifera have hardly been observed in Japan. In this study, we assessed and compared the susceptibility of the two species, A. cerana and A. mellifera, using an inoculation assay. We found that migrating female mites entered the tracheae of more newly emerged bees in both species but more frequently in A. cerana than in A. mellifera. Hence, the higher susceptibility in A. cerana is proposed as a factor causing the explosive epidemic of tracheal mites in only A. cerana in Japan. Moreover, we compared grooming behaviors between the two bee species using an observation assay as a preliminary experiment, although the bees were not exposed to the presence of tracheal mites. From these observations, the frequency of autogrooming (self-grooming) on the thorax in A. cerana was lower than that in A. mellifera. The difference in susceptibility to the mite between these two species may be due to the difference in grooming behavior frequency.

Abstract 840: The modifying effects of the extract from Okinawan sweet potato leaves in mouse colon carcinogenesis

Abstract A) Introduction Okinawa is the southernmost islands in Japan. The climate is subtropical and largely different from mainland of Japan. There are various kinds of Okinawan specific plants and they have been eaten as food. Okinawa is also known as the region where has large number of centenarians. Okinawan specific plants could be the reason of longevity. Okinawan sweet potato is one of these specific plants. Since old times, Okinawan people have eaten the sweet potato leaves but this custom has not be seen in mainland of Japan. In fact, Okinawan sweet potato contains much higher polyphenols such as caffeoylquinic acid (CQA) derivatives than other vegetables. It is reported that CQA derivatives have anti-oxidative activity and anti-mutagenic activity. We examined the modifying effect of Okinawan sweet potato leave extract in two-step mouse colon carcinogenesis. B) Experimental procedures 71 male ICR mice, 5 week-old, were divided into 5 groups. Mice in groups 1-3 were given azoxymethane (AOM; 10 mg/kg body weight) by intraperitoneal injection once at experimental first week, and one week after AOM injection they were administrated 1.5% dextran sulfate sodium in drinking water for 7 days. Mice in group 1 were fed control diet (CE-2, CLEA Japan, Inc),and mice in groups 2 and 3 were fed diet contained Okinawan sweet potato leaves extract (200 ppm and 1000 ppm respectively). Mice in groups 4 and 5, which were not injected AOM, were fed diet contained Okinawan sweet potato leaves extract (1000 ppm), and control diet respectively. At 12 experimental week, all mice were sacrificed and the colon tissues were removed to count the number of preneoplastic lesion, aberrant crypt foci (ACF), and were histologically analyzed the nodules larger than 3mm on colonic mucosa. C) Results The mean number of ACF was 1.64±0.95 (/colon length cm) in group 1, 1.18±0.79 in group 2, 1.14±0.60 in group 3, respectively. In high dose treated rats (group 3), the appearance of ACF was slightly lower than that in group 1, although not significant (P = 0.09). Histopathologically, the most nodules were lymphoid follicles but some showed neoplastic lesions. The neoplastic lesions were revealed as adenoma or adenocarcinoma. The number of the neoplasm was 9, 8 and 2 in groups 1, 2 and 3, respectively. The tumor incidence in group 3 was inhibited those in groups 1 and 2 (P&amp;lt;0.05 by Fisher exact test). No ACF and neoplastic lesions were observed in groups 4 and 5. D) Conclusion It was shown that Okinawan sweet potato leave extract has a possibility to prevent the development and progression of neoplasms in mouse colon carcinogenesis model. Citation Format: Saori Nakachi, Ai Tokeshi, Reika Takamatsu, Kazunari Arakaki, Masatsugu Uehara, Akira Iguchi, Junsei Taira, Naoki Yoshimi. The modifying effects of the extract from Okinawan sweet potato leaves in mouse colon carcinogenesis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 840.