Northern Japan Research Articles

IRSL and post-IR IRSL dating of multi-grains, single grains, and cobble surfaces to constrain fluvial responses to climate changes during the last glacial period in the Tokachi Plain, northern Japan

Accurate chronologies of fluvial terraces are necessary to understand fluvial responses to climate and sea-level changes and uplift. Although feldspar post-infrared infrared stimulated luminescence (post-IR IRSL, or pIRIR) dating has been used to establish chronologies for Pleistocene fluvial terraces, the signals can be partially bleached in short, high-gradient river systems typical of Japanese rivers, resulting in overestimated ages. This study investigated aggradational fluvial terraces formed on the Tokachi Plain, northern Japan, during the last glacial period, and true depositional ages of the deposits were estimated by comparing multi-grain IRSL50/150, pIRIR50/150, and pIRIR50/225 ages, with single-grain pIRIR50/225 ages. IRSL50/225 and pIRIR50/225 ages of granite cobbles were also obtained and compared with the ages of multi-grains to evaluate the reliability of cobble ages. Fading-corrected IRSL 50/150 ages of multi-grains were consistent with pIRIR50/150 ages, indicating that the fading correction of IRSL50/150 signal was successful. Although equivalent dose distributions of single grains suggest that the pIRIR50/225 signal was completely bleached at deposition, pIRIR50/225 ages were slightly older than fading-corrected IRSL 50/150 and pIRIR50/150 ages possibly because of small residual doses. Fading-corrected IRSL50/225 and fading-corrected pIRIR50/225 ages of granite cobbles were consistent with the fading-corrected IRSL50/150 and pIRIR50/150 ages of multi-grains. However, comparison of cobble ages with climate records seems difficult due to their large errors. The fading-corrected IRSL50/150 and pIRIR50/150 ages of multi-grains indicate that fluvial aggradation occurred at 70–60 ka, followed by incision. Changes in the strength of East Asian summer monsoon precipitation are sufficient to explain fluvial evolution in the Tokachi Plain. Although some previous studies have argued that the ages of fluvial terraces might not be simply correlated to climate changes because of complex fluvial responses, significant changes in precipitation in the study area might have dominated the evolution of the entire fluvial system. Comparison with other fluvial systems in Japan suggests that slight differences in the responses of different fluvial systems to climate changes might be due to the spatial variability of those changes.

Epidemiology of fragility fracture of the pelvic ring: a regional population-based study in Northern Japan.

Fragility fracture of the pelvic ring (FFP) is common among older patients; however, little information is available on the epidemiology of FFP worldwide. We aimed to identify the epidemiological characteristics of patients with FFP using a regional population-based dataset in Japan. This descriptive epidemiologic study analyzed data obtained from clinical information of patients diagnosed with FFP from January 1, 2011 through December 31, 2020 at a regional dominant hospital in Japan. We calculated the crude and age-adjusted annual incidences and the age-specific incidence and described epidemiological date, injury characteristics, walking ability before and after FFP, and mortality. Additionally, we investigated factors associated with walking ability. We identified 66 FFP patients, of whom 55 (83.3%) were female, with a mean age of 82.2 years. The crude annual incidence of FFP ranged from 35.5-121.2 per 100,000 population/year during the study period. The age-specific incidence of FFP increased after 75 and 80 years in females and males, respectively. In total, 44.4% of patients had declines in walking ability 1 year after their FFP injuries. Patients with declining walking ability were significantly older (p < 0.01), and age ≥ 80 years was significantly associated with the decline in walking ability (p < 0.01). The 1- and 5-year mortality rates were 15.4% and 39.9%, respectively. The incidence rate of FFP was 35.5-121.2 per 100,000 population/year. Age-specific incidence of FFP increased after 75 years. Our results indicate that FFP is associated with worse prognosis of walking function and life expectancy.

Timing of Izanagi-Pacific ridge subduction beneath Eurasia: Constraints from metamorphic soles in Hokkaido, Japan

The subduction of the Pacific Plate beneath Eurasia controls not only Cenozoic intraplate volcanism, but also deep-focus earthquakes along the continental margin of eastern Asia. However, the timing of subduction of the Paleo-Pacific (Izanagi)−Pacific ridge and the initial subduction of the Pacific Plate beneath Eurasia remain subjects of debate. Metamorphic soles provide key evidence for ridge subduction, and together with coeval igneous activity, they are widely used to constrain the timing of ridge subduction. Here, we present the results of a study of amphibolites from the Hidaka metamorphic belt, Hokkaido, northern Japan, which are interpreted to be metamorphic soles. Our integrated study involved secondary ion mass spectrometry (SIMS) U-Pb zircon dating, mineral chemistry, whole-rock geochemistry, and Sr-Nd-Pb-Hf isotopic analyses. SIMS U-Pb zircon dating indicates that the amphibolite-facies sole metamorphism occurred in the late Eocene. Phase equilibria modeling suggests that the peak P−T conditions of metamorphism were 8.0−9.5 kbar/700−730 °C. The amphibolites belong to the tholeiitic series, and they are relatively enriched in heavy rare earth elements relative to light rare earth elements, with depletions in Nb, Ta, P, and Ti. They have (87Sr/86Sr)i = 0.704207−0.704998, εNd(t) = +11.65 to +11.96, εHf(t) = +14.28 to +16.32, (206Pb/204Pb)i = 18.240−18.255, and (207Pb/204Pb)i = 15.522−15.525. The geochemistry of these amphibolites reveals that their protoliths had normal mid-oceanic-ridge basalt affinities, and their Pb isotopic signatures indicate Indian-type mantle rather than Pacific-type mantle. Considering the geochemistry of coeval igneous rocks, we conclude that the late Eocene metamorphism in the Hidaka metamorphic belt records the intraoceanic subduction that followed heat transfer from the incipient mantle wedge toward the top of the subducting plate, and it provides a key constraint on the timing of subduction of the Izanagi-Pacific ridge.

Beneficial and biocontrol effects of Trichoderma atroviride, a dominant species in white birch rhizosphere soil.

White birch (Betula platyphylla Suk.) is a typical pioneer tree species that is important in forest restoration in northern China, Japan, and Korea. In the present study, 37 isolates were obtained from B. platyphylla rhizosphere soils in Heilongjiang Province; they were identified as T. pleuroticola (3 isolates), T. virens (2 isolates), T. hamatum (8 isolates), T. atroviride (21 isolates, dominant species) and T. asperelloides (3 isolates). Stress tolerance tests (salt, alkali, and nutritional stress that simulated saline alkali or barren soil) and confrontation assays (with four pathogens) were performed to determine which isolates had good biocontrol ability in barren soil; the results show that T. atroviride was outstanding. Then, in order to determine the effect of T. atroviride on plants and soil, Gynura cusimbua seeds were sown and treated with a T. atroviride spore suspension, as was unsown soil. The seedlings treated using T. atroviride had significantly greater height, stem diameter, soluble protein content, soluble sugar content, and malonaldehyde (MDA) content and their catalase (CAT) activity was also significantly increased. In addition, when the plants were inoculated with Alternaria alternata, the plants treated using T. atroviride had stronger CAT activity, significantly higher soluble protein content and soluble sugar content, and significantly lower MDA content, which indicates stronger resistance and less injury caused by the pathogen. In addition, T. atroviride not only increased the content of available nitrogen and available phosphorus in the soil, but also promoted G. cusimbua seedlings' absorption of available nitrogen and available phosphorus. Thus, the characteristics of T. atroviride may make it the main factor that helps B. platyphylla colonise cut-over lands. T. atroviride, a promising biocontrol candidate, can be used in agriculture and forestry.

Recruitment status and host-fish-limitation threats to endangered freshwater pearl mussel (Margaritifera laevis) in eastern Hokkaido, northern Japan

Recruitment status and host-fish-limitation threats to endangered freshwater pearl mussel (Margaritifera laevis) in eastern Hokkaido, northern Japan

Phoretic behavior of the pseudoscorpion Megachernes ryugadensis on the Japanese wood mouse Apodemus speciosus.

Phoresy is a passive transportation behavior where one organism (phoront) disperses to a new location by attaching to another organism. Pseudoscorpions are arthropod predators that mainly live in soil, subterranean habitats, and under tree bark. Some species also live in animal nests and engage in phoresy on small mammals, suggesting close associations with these animals. However, the relationship between phoretic pseudoscorpions and hosts as well as the ecological significance of phoresy remain largely unexplored. Here, to understand the function of phoresy of Megachernes ryugadensis, phoretic on small mammals, their phoretic behavior was investigated in a deciduous forest in northern Japan; individual-level dynamics of phoresy were examined by over 3-year mark-recapture surveys that concurrently marked the host and phoront; and host characteristics, such as sex and age class, were analyzed based on a 2-year small mammal trapping survey. The primary host species was the abundant Japanese wood mouse Apodemus speciosus. Out of 132 pseudoscorpions marked, 5 were recaptured approximately 1month later. No pseudoscorpions were recaptured within the same census period (3-4days) when they were marked, indicating that phoresy events last less than one night, and pseudoscorpions are unlikely to engage in phoresy again within a few weeks of their initial engagement. Furthermore, analysis of host characteristics revealed a tendency for female mice and adult individuals to have a higher probability of being hosts compared with males and subadults, respectively. Based on the findings in this and previous studies, the function of phoresy in this species is discussed.

Multivariate statistical analysis on Japanese traditional papers, washi, for evaluation of DNA presence and quality

Traditional papermaking was a significant innovation that intrigued the information-sharing society in a wide range of the globe. The importance of finding the historical background hidden behind the historical traditional paper is critical to understanding societies in history. Advanced molecular biological research is applied to many forensic studies to identify the origin and criminal events. Yet, biological research refrained from the heritage science of traditional papers due to its damage to the samples. The current study explores the Pearson correlation between DNA in traditional paper and non-destructive measurement of characteristics of traditional paper. DNA concentration and purity were found to have a proportional relationship based on the CIEL*a*b* color system. The color of the traditional paper was assessed assessment shows green and yellow rather than red and blue. The DNA concentration demonstrated a positive linear correlation with the peaks of 992 cm−1, 1599 cm−1, and 1628 to 1638 cm−1 region, which were lignin-specific functional groups. The presence of lignin in traditional paper defines the colors green and yellow, which is related to the presence of a cell wall. The quantity of cell walls present is linked to DNA survival during the traditional papermaking process. Furthermore, the partial least square (PLS) regression model is established. The prediction model based on DNA, paper properties, and smoothing + the second derivative preprocessed attenuated total reflection-Fourier-transform infrared (ATR-FTIR) spectral data demonstrated valid purity predictions. The evaluation parameter of the cross-validated prediction model contains a low Root Mean Square Error of Cross-Validation (RMSECV) of 0.091 for DNA purity. The determination coefficient was close to 1. However, the further establishment of a validated DNA extraction methodology is required for the consistency of the prediction model for DNA concentration. The hierarchical clustering analysis demonstrated the agglomerative dendrogram on traditional paper samples. For the dendrogram, the Nasu paper mulberry (originating in northern Japan) was distinguished from another paper mulberry (originating in southwestern Japan) by clustering. By multivariate statistical analysis, the DNA presence and quality were predictable from the Japanese traditional papers. In addition, the clustering analysis provided the possible origin of paper mulberry materials for traditional papers. Based on the preliminary information, the need for DNA analysis on historical traditional paper can be determined.

Morphological and molecular characterization of a new species of the genus Echinorhynchus Zoega in Müller, 1776 (Acanthocephala: Echinorhynchidae) parasitizing the rock greenling Hexagrammos lagocephalus (Pallas) (Scorpaeniformes: Hexagrammidae) from eastern Hokkaido, Japan.

A new species of marine-fish-parasitizing echinorhynchid palaeacanthocephalan, Echinorhynchus sasakiae sp. nov., is described based on material from the intestine of the rock greenling Hexagrammos lagocephalus (Pallas) obtained in two localities (Akkeshi and Nemuro) in Hokkaido, northern Japan. Echinorhynchus sasakiae sp. nov. can be distinguished from other congeners by having an oval-shaped proboscis covered with hooks arranged in 14-15 rows, each consisting of 7-10 hooks that are anteriorly short and curved, but posteriorly long and weakly curved. The phylogenetic position of Echinorhynchus sasakiae sp. nov. is inferred based on three gene markers (cytochrome c oxidase subunit I, 18S rRNA, and 28S rRNA) along with relevant sequences from ten congeners available in public databases. Echinorhynchus sasakiae sp. nov. represents the 54th member of the genus and the ninth marine congener known from Japan.

Effects of heatwave events on the seagrass-dwelling crustacean Pandalus latirostris in a subarctic lagoon

Heatwaves often cause mass mortality of organisms in seagrass areas, and they eventually alter some ecological functions of seagrass ecosystems. In subarctic regions, however, the effects of heatwaves on seagrass areas are still unclear. In a subarctic lagoon of northern Japan, we examined the effects of heatwaves on the Hokkai shrimp, Pandalus latirostris, a commercially exploited species distributed in seagrass areas of northern Japan and eastern Russia. A long-term survey of the surface water temperature in the lagoon clarified a gradual increase in the frequency and intensity of heatwave events since 1999. Surveys of the water temperature at a seagrass area in the lagoon during summer have also demonstrated that the maximum water temperature had been exceeding 25 °C, unusually high for this location, regardless of water depth. These results indicate that the effects of heatwaves in seagrass areas in a subarctic region had become as severe as those in tropical and temperate regions. We also experimentally evaluated the effects of this unusually high water temperature (25 °C) on the survival of P. latirostris by changing the length of exposure time. Some individuals suffered damage to their intestinal mucosal structure after exposure for 12 h or longer, and all individuals died after exposure for 120 h. Our results suggest that heatwaves possibly cause mass mortality in P. latirostris in the following sequence: heat stress, damage to the intestinal epithelial mucosal structure, degradation of nutrient absorption and immunological function of the intestine, energy deficiency and disease infection, and finally mortality. This study, conducted in subarctic closed waters, concludes that it is essential to become familiar with not only trends in heatwaves but also the intermittent occurrence of unusually high water temperature in seagrass areas in order to better understand the process of mortality of organisms that inhabit these ecosystems.

Attitudes of different religions towards breast milk bank: Analysis of 17 countries with data mining

Breast milk is considered the best source of nutrition for infants. The establishment of breast milk banks for infants who cannot consume breast milk has always been a subject of debate from the past to the present. Religious orientations and cultures have shaped positive or negative attitudes towards these debates. This study aimed to determine and compare the attitudes towards breast milk banks in different religions. In this cross-sectional study, data were collected from people living in Turkey, Nigeria, Pakistan, India, Nepal, Madagascar, the Turkish Republic of Northern Cyprus, Azerbaijan, Iran, Mexico, Japan, England, Malaysia, Albania, Libya, Bangladesh, and Indonesia between May 2022 and April 2023. The study was conducted with individuals from Islam, Christianity, Hinduism, Buddhism, atheism, and other religions. The sample was determined using snowball sampling and the research was carried out with 2714 individuals from different religions who agreed to participate in the study. Data were collected using an Introductory Information Form and a “Questionnaire for Attitudes Towards Breast Milk Bank”. R programming language 4.1.3 was used for regression analysis with machine learning approach and artificial neural networks, and SPSS-25 was used for other statistical analyses. There was a significant difference between the individuals' mean total score on the Questionnaire for Attitudes towards Breast Milk Bank and their religious beliefs (p < 0.05). According to the results of the regression model, which was established to reveal the effect of religious belief on the attitude towards breast milk banks, statistical estimates of the regression model showed that the model was meaningful and applicable (F(5,2708) = 14.749, p = 0.001). Religious belief explained 2.7 % of the total variance in the level of attitudes towards breast milk banks. According to the results of the t-test regarding the significance of the regression coefficient in the regression model, the mean scores regarding the attitude towards breast milk banks were higher among participants from Hinduism (t = 6.971, p < 0.001), Christianity (t = 4.690, p < 0.001), Buddhism (t = 3.442, p < 0.001), and atheism (t = 4.424, p < 0.001) compared to those from Islam (constant). Individuals' attitudes towards breast milk banks differ according to their religions. The most important model in prediction with data mining was K nearest neighbour regression. It was determined that the attitudes of individuals from Islam were more negative than that of individuals from other religions. It is recommended that longitudinal studies be carried out on attitudes towards breast milk banks.

Yearly Fluctuations in Honey Production in Hokkaido, Northern Japan, with Special Reference to Weather Conditions and Masting Behavior

The factors controlling yearly fluctuations in honey production are poorly understood. To evaluate yearly fluctuations in honey production, the coefficient of variation (CV) and the autocorrelation analysis were used to determine the magnitude and periodicity of the fluctuations for seven major nectar-source plants (basswood, black locust, Amur cork tree, white clover, buckwheat, Kamchatka thistle, and horse chestnut) using 15-years of data obtained in Hokkaido, Japan. Regression analysis was conducted to evaluate the relationship between annual honey production and the corresponding weather conditions during the flowering month. The periodic synchronous flowering and fruiting observed in tree species is called masting or masting behavior. A masting model, based on the resource budget, was applied to tree species if periodicity was detected by an autocorrelation analysis. The CV differed markedly among species. Black locust and the Amur cork tree had the smallest and largest CVs, respectively, whereas basswood was periodic. A negative correlation was observed between monthly precipitation and honey production in black locust, white clover, thistle and the Amur cork tree. This result implies that rain inhibits honey bee foraging. Production of buckwheat honey, however, tended to increase with increasing mean temperature. It might be difficult to detect the effect of rain on the honey production using buckwheat presumably because of the long flowering period. Annual honey production in basswood could be described by the resource budget model, but not in horse chestnut. Some horse chestnut trees produce flowers even in non-mast year implying that it was difficult to detect the periodicity in this species. According to beekeepers, honey production in this last decade in Hokkaido has been disrupted by climate change and the transitioning of the industrial structure.

Shrinking pupal cocoons of Rhyacophila lezeyi (Trichoptera, Rhyacophilidae) in a highly acidic stream during the summer season

Shrinking pupal cocoons of Rhyacophila lezeyi were often found during summer in Shibukuro Stream, a highly acidic mountain stream in northern Japan (pH = 2.82 on average). We performed both field surveys and laboratory rearing experiments to clarify the mechanisms of R. lezeyi cocoon shrinkage. The R. lezeyi cocoon shrinkage proportion increased in years with high stream water temperatures and was related to water temperatures before and after pupation at the study site. Approximately 90% of the prepupae and pupae inside the shrinking cocoons died during the rearing experiment, implying that cocoon shrinkage caused by high water temperature strongly influenced R. lezeyi pupal survival. Laboratory experiments showed that R. lezeyi’s pupal cocoon membranes were semi-permeable and that the cocoon fluids were always hyperosmotic, indicating that water molecules can continuously enter the cocoon fluids from the stream water until the turgor of the cocoon wall is reached. However, the shrinking cocoons showed lower fluid volume and higher osmolarity than the normal turgescent cocoons. The reduction of osmotic gradient across the membrane during decreased stream flow due to less precipitation and/or the damage to the cocoon membrane and pupal body from high and fluctuating water temperatures and low pH are possible mechanisms for R. lezeyi pupal cocoon shrinkage.

Attempts to isolate genes that determine the good taste on landrace edamame soybeans

Dadachamame is the common name for edamame soybean [Glycine max L.(Merr.)] cultivars, ‘Shirayama’, ‘Kanro’ and ‘Oura’, which have been established in Tsuruoka city, Yamagata prefecture in northern Japan since the late Edo era. Dadachamame has a good taste and special aroma. Although it is known that the good taste of Dadachamame is caused by the higher levels of sucrose and free amino acids based on the comparative analysis of chemical components in the seeds of Dadachamame and other soybean cultivars, details on the genetic level are unclear. To understand the good taste of Dadachamame on the genetic level, in this study, we developed an F2 population derived from a cross between the Dadachamame cultivar ‘Shirayama’ and the soybean cultivar ‘Enrei’. In the early development stage, Shirayama seeds had about 2-fold higher accumulation levels of sucrose compared with Enrei seeds. Sucrose content and genotype of the F2 population suggested that the quantitative trait locus (QTL) for high sucrose accumulation is located on the long arm of chromosome 12. The genes responsible for determining the sweetness of Shirayama may be present on chromosome 12. Using the lines developed from crosses between Dadachamame and soybean cultivars in future studies, we will attempt to identify the genes responsible for QTL that control for the good taste in specific Dadachamame seeds, and discuss the mechanisms for determining the good taste of Dadachamame to improve the palatability of edamame. Furthermore, we have developed mutant edamame populations that can be used for edamame breeding. Since mutant soybean populations have already been developed, meticulous soybean breeding will be possible in the future for creating the desired characteristics for the final soybean products.

Origins of the Ainu Religious Conversion at Hokkaido in Japan

The Ainus in Japan were the indigenous people who lived in Northern Japan and Russia. Before the Russian and Japanese arrived in Japan, the Ainu people had their own culture, rituals and values. In their culture, natural spirits exist everywhere. This view is often referred to as Kamui. However, recent studies have shown that the majority of the Ainu community nowadays do not believe in their native religion. Instead, they are mostly believers of Shintoism and Buddhism. This paper traces the origin of the Ainu religion and how the primary religion of the Ainu community has changed to todays situation. The study relies mainly on existing literature. By analyzing interviews, journal articles, and books, the paper seeks to provide a new perspective in understanding the Ainu religion and the influence of religion among indigenous people.

Four-year field survey on francisellosis in Yesso scallops Mizuhopecten yessoensis cultured in southern Hokkaido, Japan

Lethal impact of the bacterium Francisella halioticida on Yesso scallops Mizuhopecten yessoensis has been experimentally demonstrated, but epidemiological information for this bacterium infection in scallop farms has been limited. Thus, the present study conducted a monthly epidemiological survey for 4 years on adult scallops ear-hung from 2017 to 2020 on a scallop farm in northern Japan. As a result, the prevalence of F. halioticida in low temperature period increased for all year groups, but any association with scallop mortality was recognized. On the other hand, in the 2017–2019 year groups, increase of the prevalence and rapid declines of scallop survival were recognized in high-temperature periods. Additionally, overall survival in these year groups were apparently lower than the 2020 year group without increase of the prevalence in high-temperature period, suggesting that infection of F. halioticida in high-temperature periods may be associated with mortality of scallops. Abscess lesions in the adductor muscle were found to be associated with F. halioticida infection, but not always formed in infected scallops. Thus, presence of abscess lesions may serve as an indicator for francisellosis, but not necessarily a definitive symptom for this disease.

Thermosteric and dynamic sea level under solar geoengineering

The IPCC sixth assessment report forecasts sea level rise (SLR) of up to 2 m along coasts by 2100 relative to 1995–2014 following business as usual (SSP585) scenarios. Geoengineering may reduce this threat. We use five Earth System Models simulations of two different solar geoengineering methods (solar dimming and stratospheric sulfate aerosol injection), that offset radiative forcing differences between SSP585 “no-mitigation” and the modest mitigation SSP245 greenhouse gas scenarios, to analyze the impact on global mean thermosteric and dynamic regional sea levels. By 2080–2099, both forms of geoengineering reduce global mean thermosteric sea level by 36–41% (11.2–12.6 cm) relative to SSP585, bringing the global mean SLR under SSP585 in line with that under SSP245, but do not perfectly restore regional SLR patterns. Some of the largest reductions (∼18 cm) are on densely populated coasts of eastern Northern America and Japan and along vulnerable Arctic coastal permafrost.

Dietary Habits of Japanese Badgers (Meles anakuma) in Northern Japan: Relationship with Food Availability

Dietary Habits of Japanese Badgers (Meles anakuma) in Northern Japan: Relationship with Food Availability

Automated estimation of stomatal number and aperture in haskap (Lonicera caerulea L.).

This study developed the reliable Mask R-CNN model to detect stomata in Lonicera caerulea. The obtained data could be utilized for evaluating some characters such as stomatal number and aperture area. The native distribution of haskap (Lonicera caerulea L.), a small-shrub species, extends through Northern Eurasia, Japan, and North America. Stomatal observation is important for plant research to evaluate the physiological status and to investigate the effect of ploidy levels on phenotypes. However, manual annotation of stomata using microscope software or ImageJ is time consuming. Therefore, an efficient method to phenotype stomata is needed. In this study, we used the Mask Regional Convolutional Neural Network (Mask R-CNN), a deep learning model, to analyze the stomata of haskap efficiently and accurately. We analyzed haskap plants (dwarf and giant phenotypes) with the same ploidy but different phenotypes, including leaf area, stomatal aperture area, stomatal density, and total number of stomata. The R-square value of the estimated stomatal aperture area was 0.92 and 0.93 for the dwarf and giant plants, respectively. The R-square value of the estimated stomatal number was 0.99 and 0.98 for the two phenotypes. The results showed that the measurements obtained using the models were as accurate as the manual measurements. Statistical analysis revealed that the stomatal density of the dwarf plants was higher than that of the giant plants, but the maximum stomatal aperture area, average stomatal aperture area, total number of stomata, and average leaf area were lower than those of the giant plants. A high-precision, rapid, and large-scale detection method was developed by training the Mask R-CNN model. This model can help save time and increase the volume of data.

Access to mechanical thrombectomy and ischemic stroke mortality in Japan: a spatial ecological study.

Advances in stroke treatment have greatly improved outcomes; however, disparities in access to treatment might increase. Achieving equitable access to stroke treatment is a health policy challenge, as rapid treatment is essential for positive outcomes. This ecological cross-sectional study aimed to determine the relationship between the disparities in spatial accessibility to mechanical thrombectomy (SAMT) and stroke mortality rates in Japan, hypothesizing that disparities in SAMT may increase the differences in stroke mortality between regions. We used the average number of ischemic stroke (IS) deaths between 2020 and 2021 as the response variable; and SAMT, medical resources, and socioeconomic characteristics of each municipality as explanatory variables. A conditional autoregressive model was used to examine the association between the risk of stroke mortality and SAMT. The standardized mortality ratio (SMR) was mapped to understand the nationwide disparities in stroke mortality risk. The median number of IS deaths was 17.5 persons per year in the municipalities (2020 to 2021). The study also found that municipalities with low SAMT were located in the northern part of Japan. The non-spatial regression model results indicated that poor accessibility, a small proportion of bachelor's degrees or higher, and a high proportion of workers in secondary industries were related to high IS mortality. Three models were evaluated using spatial analysis; Model 1 with accessibility indicators alone, Model 2 with medical resources added to Model 1, and Model 3 with socioeconomic characteristics added to Model 2. In Models 1 and 2, the population-weighted spatial accessibility index (PWSAI) showed a significant negative relationship with stroke mortality. However, this was not evident in Model 3. Mapping using Model 3 showed that the high-risk areas were predominantly located in northern Japan, excluding Hokkaido. Access to mechanical thrombectomy was estimated, and regional differences were observed. The relationship between accessibility and IS mortality is unknown; however, regardless of accessibility, municipalities with a high proportion of workers in secondary industries and a small proportion with bachelor's degrees or above are at risk of death from stroke.

Geographical variation in parasitoid communities and the cause of enemy-free space in a range-expanding myrmecophilous lycaenid butterfly

Abstract Range expansions of host species are likely to modify host–parasitoid interactions. Observational studies have indicated that host species in recently colonized areas are less frequently attacked by parasitoids; however, these studies did not determine whether traditional parasitoids can still use host populations in these areas. Thus, it is unclear why the host has escaped from their traditional parasitoids in their recently colonized areas. In this study, we examined the interaction between myrmecophilous lycaenid butterfly, Arhopala japonica, and its larval parasitoids in northern Japan, a recently colonised area. This region corresponds to a distribution of A. japonica, a myrmecophilous lycaenid butterfly. No parasitoids emerged from A. japonica larvae collected in the north, whereas six parasitoid species attacked the host larvae in native areas. Attacks from the braconid wasp Cotesia sp. near inducta were the most common; however, parasitism tests revealed that Cotesia sp. near inducta and other parasitoid species completed their development successfully regardless of origin of their butterfly hosts. Population genetic analyses supported the recent range expansion of both A. japonica and Cotesia sp. near inducta. These results suggest that both hosts and parasitoids have experienced recent population expansion; however, the more rapid range expansion of A. japonica has caused escape from the enemy in newly colonized areas.