Okayama Prefecture Research Articles

Effects of a Forest Walk on Urinary Dityrosine and Hexanoyl-Lysine in Young People: A Pilot Study.

A few studies indicate exposure to forests may alleviate oxidative stress in the body. However, more evidence is needed to support this potentiality. The purpose of the current study aimed at examining whether there is any difference in urinary levels of oxidatively modified proteins or lipids—dityrosine (DT) and hexanoyl-lysine (HEL), respectively, after a forest or urban walk. The study was performed on 29 university students who took part in forest walks (Shinjo Village) in Okayama Prefecture of Japan and on 42 university students who took part in urban walks in the downtown area of Okayama City. Urine samples before and after the walks were analyzed for DT and HEL excretion. Air phytoncides during the walks were also measured. We found a decreased tendency in urinary DT and HEL (p < 0.05) in most participants after the forest walks, but not after the urban walks. We further found the total levels of air phytoncides in the forest field were 1.50 times higher compared with those in the urban field. This study suggests the possibility that regular immersion in a forest environment might contribute toward weakening of the oxidative modifications of proteins or lipids in the body.

Geochemical and isotopic imprints of groundwater evolution in mountainous areas of Maniwa City, Okayama Prefecture, Japan

Groundwaters mainly along the Asahi River in Maniwa City, a mountainous area in Okayama Prefecture, have been supplied as tap water to the residence. To examine the source and water quality of the groundwaters, chemical and isotopic (δD and δ18O) analyses were conducted on 58 shallow groundwater and 30 river water samples collected from 51 water intake facilities twice during winter (February–April) and summer (August–September) in 2017. Three hot springs were also sampled. The water temperatures of the groundwater in the northern area was almost constant throughout the year, whereas seasonal temperature variation was observed in the other area. Groundwater samples were plotted along a line with slope 3 in a δD vs. δ18O diagram. Both δD and δ18O of the groundwater showed tendencies to be low in the north and high in the south due to altitude effect. The groundwater sampled here had low electric conductivity and samples in the north and south were rich in SiO2 and Ca2+–HCO3−, respectively. This strongly reflects the influence of regional geology, containing diatomite in the north and limestone in the south. These results indicate that the groundwater in Maniwa City flows near the surface and that their residence times are several months except for groundwater in the northern mountains. From the major and trace components, the groundwater in Maniwa City are judged to be safe as drinking and agricultural water.

Application of GETFLOWS Coupled with Chemical Reactions to Arsenic Removal through Ferrihydrite Coprecipitation in an Artificial Wetland of a Japanese Closed Mine

Passive systems that utilize a natural power such as a pond, plant, or microorganisms, is expected to be a cost-effective method for acid mine drainage (AMD) treatment. The Ningyo-toge mine, a non-operational uranium mine located in Okayama Prefecture, Japan, generates AMD containing arsenic and iron. To quantitatively study arsenic and iron ion removal in an artificial wetland and pond, chemical reactions were modeled and incorporated into the GETFLOWS (general-purpose terrestrial fluid-flow simulator) software. The chemical reaction models consisted of arsenite and ferrous oxidation equations and arsenic adsorption on ferrihydrite. The X-ray diffraction analysis of sediment samples showed ferrihydrite patterns. These results were consistent with the model for arsenite/ferrous oxidation and arsenic adsorption on ferrihydrite. Geofluid simulation was conducted to simulate mass transfer with the utilized topographic model, inlet flow rate, precipitation, and evaporation. The measured arsenic and iron ions concentrations in solution samples from the wetland and pond, fitted well with the model. This indicated that the main removal mechanism was the oxidation of arsenite/ferrous ions and that arsenic was removed by adsorption rather than dilution.

The Seimei telescope project and technical developments

ABSTRACT An overview of the Seimei telescope, a 3.8 m optical infrared telescope located on Mt. Chikurinji in the Okayama prefecture of Japan, is presented. Seimei is a segmented-mirror telescope whose primary mirror consists of 18 petal-shaped segments. The telescope tube supporting the thin segmented mirrors is structurally incorporated within large arc-rails providing the elevation axis. The tube has a light-weight homologous structure designed with a genetic algorithm. The total weight of the telescope tube, including 1.4-ton optics, is only 8 tons. By virtue of its light weight, the telescope is able to point at an object anywhere in the observable sky within one minute. The telescope is operated by Kyoto University in collaboration with the National Astronomical Observatory of Japan (NAOJ). Half of the telescope time is used by Kyoto University. The remaining time is open to the Japanese astronomical community. NAOJ is responsible for the management of the open-use time, including handling of the observation proposals. The telescope is now regularly performing scientific observations on the basis of a variety of proposals.

Inundation Analysis of the Oda River Basin in Japan during the Flood Event of 6–7 July 2018 Utilizing Local and Global Hydrographic Data

During the first week of July 2018, widespread flooding caused extensive damage across several river basins in western Japan. Among the affected basins were the Mabicho district of Kurashiki city in the lower part of the Oda river basin of the Okayama prefecture. An analysis of such a historical flood event can provide useful input for proper water resources management. Therefore, to improve our understanding of the flood inundation profile over the Oda river basin during the period of intense rainfall from 5–8 July 2018, the Rainfall-Runoff-Inundation (RRI) model was used, with radar rainfall data from the Japan Meteorological Agency (JMA) as the input. River geometries—width, depth, and embankments—of the Oda river were generated and applied in the simulation. Our results show that the Mabicho district flooding was due to a backwater effect and bursting embankments along the Oda River. The model setup was then redesigned, taking into account these factors. The simulated maximum flood-affected areas were then compared with data from the Japanese Geospatial Information Authority (GSI), which showed that the maximum flood inundation areas estimated by the RRI model and the GSI flood-affected area matched closely. River geometries were extracted from a high-resolution digital elevation model (DEM), combined with coarser resolution DEM data (global data), and then utilized to perform a hydrological simulation of the Oda river basin under the scenarios of backwater effect and embankment failure. While this approach produced a successful outcome in this study, this is a case study for a single river basin in Japan. However, the fact that these results yielded valid information on the extent of flood inundation over the flood-affected area suggests that such an approach could be applicable to any river basin.

Geophysical surveys over and inside the Tobiotsuka Kofun – Okayama prefecture

Burial mounds are artificially (or partially artificially) erected hills that cover a monumental tomb, usually in the form of a stone chamber. Different types of burial mounds are distributed worldwide and have built in different archaeologically interesting periods. Use of non destructive geophysical surveys for their study offer the opportunity to image their internal structure and evidence peculiar anomalies that can be later investigated with archaeological excavations, limiting invasiveness. The main innovative part of this work lies on the combined use of Ground Penetrating Radar and Electric Resitivity Tomography over and inside an unexplored burial site in Japan, the Tobiotsuka Kofun, a late Kofun period burial mound, dated approximately late 6th-early 7th century CE and located in the Okayama Prefecture. Effectiveness of the geophysical surveys is demonstrated by the correct imaging of known structures and by the combined evidence of the mound organization, which allowed to draw a reliable initial archaeological interpretation with evidence of several interesting excavation spots. The adopted methodological surveying approach was verified as a valuable choice for investigations in similar archaeological settings.

Annual Variation of the Grain Shattering Degree in Main Rice Cultivars in Okayama Prefecture, Japan

Annual Variation of the Grain Shattering Degree in Main Rice Cultivars in Okayama Prefecture, Japan

The Regional Economic and Fiscal Circulation in Forest and Lumber Industry: The Case Study of Nishiawakura Village, Okayama Prefecture

The Regional Economic and Fiscal Circulation in Forest and Lumber Industry: The Case Study of Nishiawakura Village, Okayama Prefecture

Examining the Effects of the Support Mechanism Enabling Female Doctors Raising Children to Resume Full-Time Work: A Case Study of the MUSCAT Project in Okayama Prefecture

Examining the Effects of the Support Mechanism Enabling Female Doctors Raising Children to Resume Full-Time Work: A Case Study of the MUSCAT Project in Okayama Prefecture

Monthly Changes and Yearly Comparisons in the Taste of Pacific Oysters（Crassostrea gigas）Cultured in the Okayama Prefecture

Monthly Changes and Yearly Comparisons in the Taste of Pacific Oysters（<i>Crassostrea gigas</i>）Cultured in the Okayama Prefecture

Fact-finding about early hand prosthesis fitting for finger amputation and partial hand amputation in Okayama Prefecture

Fact-finding about early hand prosthesis fitting for finger amputation and partial hand amputation in Okayama Prefecture

The Characteristics of Perceived Difficulties in Everyday Technology Use among Individuals with Acquired Brain Injury Compared to That among Controls

Objectives: People with acquired brain injury (ABI) have various difficulties when using everyday technology (ET) in their daily life. The aim of this study was to reveal the characteristics of perceived difficulties of people with ABI when using ET through a comparison with the control group. Method: We recruited participants in the Kansai area and Okayama prefecture between 2010 and 2015. A total of 24 participants (18 males and 6 females; aged 20 to 62 years; mean age: 42.6 ± 13.3 years) with ABI and 26 healthy controls were interviewed about their perceived difficulties using ET via the Everyday Technology Use Questionnaire revised Japanese version (ETUQ-Japan). Results: Compared to the controls, the mean number of ETs used by people with ABI was significantly lower. When various difficulties arose, they were unable to independently manage ET, requiring the assistance of caregivers. Conclusion: It is necessary for the medical staff, involved in the home life of patients with ABI to consider the patient’s perceived difficulties when using ET.

Secular changes in total steps and moderate-to-vigorous physical activity among fourth-grade students in Japan in 2003/2004 and 2016/2017

ABSTRACTNo study has investigated secular changes in both total steps and moderate-to-vigorous physical activity (MVPA) among Japanese children. This study examined the secular changes of total steps and MVPA among fourth-grade students in Japan in 2003/2004 and 2016/2017. It was performed at a school in Okayama Prefecture in Japan. A total of 452 participants (226 boys and 226 girls; mean age, 9.6 ± 0.5 years) participated in the study. We measured total steps and MVPA of the participants by using the same methods in 2003/2004 and 2016/2017. An uniaxial accelerometer was used to measure total steps and MVPA. On weekdays and weekends, the total steps and MVPA were lowered by approximately 1,000–3,000 steps/day and 10 min/day, respectively, in boys and by 1,000 steps/day and 5 min/day, respectively, in girls in 2016/2017 in comparison to 2003/2004. In both boys and girls, the percentage of children meeting 60 minutes/day of MVPA decreased in 2016/2017(weekdays: boys 21.8%, girls 6.0%; weekends: boys 3.8%, girls 4.1%) compared with 2003/2004 (weekdays: boys 48.2%, girls 11.6%; weekends: boys 7.8%, girls 7.6%). In conclusion, the results demonstrated that total steps and MVPA of fourth-grade students in Japan were lower in 2016/2017 than in 2003/2004.

岡山県南東部における夜間・休日の耳鼻咽喉科救急診療の実状

To clarify the scenario regarding the emergency medical treatment of patients undergoing otolaryngology in southeastern Okayama Prefecture in Japan, we evaluated the conditions in three hospitals that mainly provide emergency medical treatment to patients undergoing otorhinolaryngology at night or on holidays. The data (age, sex, type of disease, and address) of patients who visited Japanese Red Cross Okayama Hospital, Kawasaki Medical School General Medical Center, and Okayama Medical Center in 2018 were collected and compared. All three hospitals reported many cases of tonsillar abscess and nasal bleeding. In the study population, the number of patients aged ≤10 and 10-20 years were the lowest and highest, respectively. Patients residing in southern Okayama City and Tamano City tended to visit Japanese Red Cross Okayama Hospital or Kawasaki Medical School General Medical Center. Patients residing in northeastern Okayama Prefecture and northern Okayama City tended to visit Okayama Medical Center. A ceiling for the senior physicians’ capacity will be introduced in April 2020, and thus the number of otolaryngology-related treatments performed in Okayama Prefecture is expected to decrease. The otolaryngologyrelated emergency medical treatment in southeastern Okayama Prefecture may collapse. Emergency medical care systems must therefore be considered in the future.

Low Consultation Rate of General Population with Atrial Fibrillation.

In order to prevent ischemic stroke, it is important to identify and treat patients with atrial fibrillation (AF) who do not consult a doctor in a medical institution. The aim of this study was to determine the consultation rate at medical institutions for patients with AF in group medical examinations conducted in a city in western Japan. Of 6101 examinees of group medical examinations (40 years of age or older) conducted in Ibara City, Okayama Prefecture, Japan, from 2012 to 2014, 4338 participants (71.1%) who were evaluated by electrocardiogram (ECG) gave written informed consent and responded to surveys in the form of questionnaires through a personal interview conducted by nurses were included in the Ibara-AF study. A cumulative total of 82 subjects were diagnosed as having AF by ECG (prevalence of AF = 1.89%), and 51 individuals had AF during the three-year period.15 (29.4%) of the 51 patients with AF did not regularly visit medical institutions. Among them, 46.7% (n = 7) and 53.3% (n = 8) of the patients were symptomatic and asymptomatic, respectively, and 73.3% of the patients had a CHADS2 score of more than one point. There were no significant differences in patients' characteristics between regular and non-regular visit groups. In conclusion, about one-third of the patients with AF did not regularly see a doctor in a medical institution and most of them had a CHADS2 score of more than one point in a Japanese rural area. Educating the public about the risks of AF is required.

Evacuation Behavior of Facilities for the Elderly in the Heavy Rain of July 2018

The heavy rain disaster in July 2018 caused significant damages such as leaks and inundation above floor level at many facilities for the elderly. In the present study, we surveyed facilities for the elderly near Oda River, Okayama Prefecture, and those near Hiji River, Ehime Prefecture, to study the necessity of a facility-specific criterion to start evacuation on the basis of the characteristics of the facilities used by people who need care. The results of the survey indicated that evaluation information released by the local government might not ensure sufficient evacuation time. An example of a criterion to start evacuation based on the water level of a nearby river or the amount of dam discharge was shown as one of the ways that each facility voluntarily makes decisions on fast evacuation.

Mortality by Age Group and Municipality in the July 2018 Torrential Rainfall

The July 2018 torrential rainfall caused tremendous damage to western Japan, claiming the lives of 237 people. This research analyzed the mortality due to the disaster by age group and municipality and compared it with historical records of past wind and flood disasters. The analysis confirmed that the total death toll of 237 including 115 deaths in Hiroshima Prefecture alone was the second highest in 41 years since 1978, following 427 deaths including 294 in Nagasaki Prefecture in the Nagasaki Great Flood in 1982. The analysis also found that the mortality rate in the age group 70 years and more was extremely high in Mabi Town of Kurashiki City, Okayama Prefecture and Saka Town, Hiroshima Prefecture, compared with that recorded in past disasters. Moreover, the paper discusses practical target setting for future mortality reduction by comparing the mortality rates in past disasters.

Distribution and Characteristics of Slope Movements in the Southern Part of Hiroshima Prefecture Caused by the Heavy Rain in Western Japan in July 2018

Record-breaking heavy rainfall in July 2018 caused an extremely large number of slope movements over a broad area of western Japan. We mapped the distribution of slope movements in the southern part of Hiroshima Prefecture through an interpretation of aerial photographs that were acquired after the rainfall by the Geospatial Information Authority of Japan, and counted a total of 8,497 slope-movement starting points. The widespread distribution of slope movements – from Etajima City of Hiroshima Prefecture to Kasaoka City of Okayama Prefecture – suggests that the heavy rain affected a very large area. The starting points of debris flow during this disaster were commonly close to the crest of mountain ranges. We compared the distribution of slope movements to the 24-hr rainfall accumulation during the heaviest rainfall event to clarify the factors that caused regional difference in slope-movement distribution. We found the area of highest density of the slope movements was consistent with the area receiving a cumulative rainfall of &gt;250 mm. This observation indicated that the position of slope-movement starting points was not related to differences in geology.

Identification of the Mitochondrial DNA Haplotype of an Invasive Linepithema humile (Mayr, 1868) (Hymenoptera: Formicidae) Population of a New Location in Japan for Its Effective Eradication

Linepithema humile is one of the most damaging invasive species worldwide. Although chemical control strategies have proven effective for L. humile, the susceptibility of these invasive ants to the insecticide fipronil differs markedly among genetically different supercolonies. In Japan, five mitochondrial L. humile haplotypes were identified from eleven prefectural regions and cities as of 2010. In 2012, a new population was found in Okayama Prefecture. Here, we analyzed mitochondrial DNA from L. humile workers from the Okayama population to better understand the genetic structure of ants in Japan and develop effective control strategies. According to COI-COII and cytochrome b gene sequences, the L. humile Okayama population haplotype was consistent with the ‘Japanese main’ supercolony—the most invasive supercolony worldwide. Hence, we believe that the Okayama population (Japanese main supercolony) can be easily eradicated because of its early invasion stage, relatively limited distribution range and high sensitivity to fipronil.

Sustainability of Upland Agriculture in Okayama Prefecture: A Case Study on a Farmers' Market in Kawakami Area, Maniwa City

In Japan, farmers' markets are important to small-scale farmers from a variety of perspectives; for example, farmers' markets guarantee a route to market and offer a sense of purpose to aging farmers. Farmers' markets are also important for farmers delivering their goods to market. The environment surrounding farmers using the markets is also important. For example, it is thought that getting advice from a certain farmer or seeing how goods are delivered can determine the means of delivery of other farmers. Moreover, the relationships between farmers and farming cooperatives do not only focus on what goods they bring to market, but also on other considerations including the diffusion of new crops among farmers and guidance on cultivation. The survival strategies of small-scale farmers in the Hiruzen region of Okayama Prefecture are examined, focusing on the management styles of farmers who deliver their produce to farmers' markets and the roles played by farming cooperatives and related organizations concerning the markets. The Hiruzen region examined is a upland rural area located in the north of Okayama Prefecture. The principal industries are agriculture and tourism. In terms of agriculture, the Hiruzen region is the largest producer of highland vegetables, such as daikon and cabbage. The daikon produced in the region is popularly known as Hiruzen Daikon, and is primarily delivered to markets in the Kansai area. As in other regions, agriculture in the Hiruzen region is facing a drop in the number of farmers because of aging, as well as competition with other regions, and is generally divided between large-scale farmers and small-scale farmers. Meanwhile, in terms of tourism, the Hiruzen region has been famous since the era of rapid growth for having the largest highland resort in Western Japan. However, group travel to the region has been declining since the 1990s with the end of an asset inflation-led economic boom. In 1992, a semi-public organization, made up at the time of Kawakami Village, farming cooperatives, and dairy farming cooperatives, set up a farmers' market as a tourism initiative designed to vitalize agriculture. The survey method consisted of oral interviews with farmers delivering their goods to the farmers' market. Specifically, they were asked how they managed their farms, the farm produce they delivered to market, opportunities to introduce farm produce, and their relationships with other farmers. Moreover, oral interviews were also conducted with managers of the farmers' market and members of farming cooperatives about their relationships with various farmers. The results reveal how links with neighboring farmers play an important role when farmers introduce farm produce. This is in contrast to previous studies that suggest farmers' markets are not places for exchanges among farmers. Furthermore, close links among farmers raise the issue of concentration on deliverables. However, this issue is being resolved through the establishment of mechanisms to distribute farm produce across large areas. Moreover, agricultural cooperatives focus on giving guidance and diffusing new crops among small-scale farmers, having become the principal reason why small-scale farmers continue to operate. Current operations of agricultural cooperatives suggest that agriculture in the Hiruzen region is being preserved.