Oshima Island Research Articles

1P2-L06 スカイラインマッチングによる方位角推定を用いた惑星探査ローバの自己位置補正(宇宙ロボット)

This paper presents that the method of position error correction for planetary rovers by using skyline matching azimuth estimation. Skyline matching is the method that estimating position and attitude by comparing two skylines. One skyline is simulated one from a digital elevation model (DEM). The other one is gotten from camera images taking around view. We focus on using azimuth attitude estimated by skyline matching to correct accumulation error of IMU. We modeled IMU angular velocity bias increases linearity. We conducted field experiments in Oshima Island and Chiba. As a result, estimated relative azimuth errors are lower than 1 degree. IMU azimuth errors decreased by 67% (6.25 deg to 2.15 deg ) and IMU position errors decreased by 70% (3.33m to 1.04m).

Inundated area and the time of the debris flows triggered by large-scale shallow landslides in Izu Oshima Island on 16 October, 2013

Inundated area and the time of the debris flows triggered by large-scale shallow landslides in Izu Oshima Island on 16 October, 2013

２. 平成25年台風第26号による伊豆大島の災害の 空中写真撮影と判読－国土地理院の対応

２. 平成25年台風第26号による伊豆大島の災害の 空中写真撮影と判読－国土地理院の対応

Relationship between activity of daily living and asteatosis in the lower legs among elderly residents in long‐term care institutions: a cross‐sectional study

This cross-sectional observational study investigated the relationship between the level of activities of daily living (ADL) and asteatosis in the lower legs among elderly residents. We enrolled 173 residents from a long-term care health facility and two special nursing homes for elderly persons in the Tokyo metropolitan area and Oshima Island, Japan. The level of ADL was measured by the Barthel Index. The relationship between the Barthel Index total score and the presence of asteatosis in the lower legs diagnosed by a dermatologist was analysed by multivariate logistic regression analysis. Among the residents, 79·2% had asteatosis in their lower legs. An increase of 1 point in the Barthel Index total score was significantly associated with a decreased probability of lower leg asteatosis after adjusting for age, sex and the type of institution (adjusted odds ratio = 0·982; 95% confidence interval: 0·966-0·998). A higher level of ADL is associated with a lower probability of having asteatosis in the lower legs among residents in long-term care institutions. Nurses should pay specific attention to residents with limited ADL for initiating preventive care for asteatosis.

Inheritance Activities of the Local Community Arts: Initiative of Schools, in Amami Oshima Island

Inheritance Activities of the Local Community Arts: Initiative of Schools, in Amami Oshima Island

1047 SALT INTAKE IN THE RESIDENTS OF JAPANESE RURAL ISLAND

Objective: To investigate salt intake and blood pressure (BP) control status in the residents of Japanese rural island. Design and Method: Subjects were 242 habitants of Oshima Island (95 men and 147 women, mean age of 70.4 years, mean BP of 144/78 mmHg, and mean body weight (BW) of 56.5 kg). They were asked to collect their first morning urine to measure salt excretion, urinary albumin, and an oxidative stress marker 8-hydroxydeoxyguanosine (8-OHDG). We also investigated their dietary habit by brief-type self-administered diet history questionnaire (BDHQ). Clinic BP was also determined Results: Among all subjects, 192 were hypertensive. Among them, 148 (77.1%) were taking antihypertensive drugs (1.9 drugs in average), and only 28.5% of them achieved the BP goal advocated by hypertension guidelines. Urinary salt excretion was 9.3 ± 2.1 g/day, while crude and energy-adjusted salt intakes evaluated by BDHQ were 10.5 ± 4.0 g/day, and 12.8 ± 3.7 g/day, respectively. Only 5.4% achieved the goal of salt restriction (< 6 g/day). Though no significant correlation was found between BP and urinary salt excretion, a significant positive correlation was found between energy-adjusted salt intake and diastolic BP (r = 0.18, p < 0.01). Urinary albumin was 29.1 ± 113.4 mg/g·Cr, urinary 8-OHDG was 11.9 ± 4.0 ng/mg·Cr. Urinary 8-OHDG was higher in females and showed positive correlation with age (r = 0.34, p < 0.01) and urinary salt excretion (r = 0.21, p < 0.01). Conclusions: Salt intake in the residents of Japanese rural island was high, which was associated with poor BP control. Salt restriction and reinforcement of hypertensive treatment is needed.

Bird strikes on window observed in Amami Oshima Island, Kagoshima Pref., Japan

Bird strikes on window observed in Amami Oshima Island, Kagoshima Pref., Japan

Tissue culture of two medicinal trees native to Japan

Wadatsuminoki (Nothapodytes amamianus) is an endangered tree species observed in only Amami Oshima Island located in southern part of Japan. According to the Red list published by Ministry of Environment, it is classified as 1A (Critically endangered) and naturally remaining number is only 20. It contains camptotesin which is used for anti-cancer drugs. Kagikazura (Uncaria rhynchophylla) is an medicinal tree species observed widely in Japan and China. It contains alkaloids (rhynchophylline, iso-rhynchophylline, hirstine and so on) which are good for remedy of high blood pressure and dementia. For the purpose of micropropagation and development of basis of useful substance production by cell culture as well as conservation of endangered species, tissue culture procedure was developed for those two species. Excised shoots of 2 years old seedling of Wadatsuminoki rooted in the 1/2DCR medium containing 3 g/l activated charcoal powder. Newly shoots were induced from in vitro root segments subcultured to 1/2MS medium containing 2uM BAP. This cycle can be used for micropropagation of Wadatsuminoki. We have succeeded in micropropagation by tissue culture of Wadatsuminoki (Figure 1). Callus proliferation from stem or root segments was observed on the 1/2LP medium containing 0.5uM BAP and 1 uM 2,4-D, this subculture cell line may be used for the possible production of secondary metabolites in vitro. Shoots were induced from stem spine (thorn) of Kagikazura in the 1/2MS medium containing BAP or Zeatin. Regenerated plants were obtained by rooting of these shoots on 1/2MS medium containing 1 uM IBA. Callus induced around the stem segments were continuously subcultured in the fresh 1/2LP medium containing 0.5 uM BAP and 1 uM 2, 4-D. These cell lines can be used for the possible secondary metabolite production and for breeding by somaclonal variation or genetic engineering.

Microsporidian Infection in Rryukyu Ayu Plecoglossus altivelis ryukyuensis on Amami Oshima Island

Cultured Ryukyu ayu Plecoglossus altivelis ryukyuensis was found to be infected with a microsporidian parasite on Amami Oshima Island in January 2009. The parasite formed numerous cysts on the visceral organs and skin of the diseased fish. High temperature seemed to suppress the development of the parasite; in 2009 and 2010, the disease occurred in the 0-year fish from April to August, and afterwards the prevalence decreased dramatically in September and October. These characteristics well resembled glugeosis in ayu P. altivelis altivelis in other areas of Japan. This parasite seems to be indigenous to Amami Oshima Island, because it was detected in the museum specimens of wild Ryukyu ayu caught in 1991. Average dimensions of spores from Ryukyu ayu were slightly shorter and wider than those of Glugea plecoglossi, but the ranges of the measurements were overlapped. From the above characteristics and molecular analysis of SSU rRNA, it was concluded that the present microsporidian was included genus Glugea, but the specific identity remained to be clarified.

Current status of the distribution of the coral-encrusting cyanobacteriosponge Terpios hoshinota in southern Japan

The cyanobacteriosponge Terpios hoshinota encrusts living coral and other benthos, and occasionally undergoes massive outbreaks, resulting in large amounts of damage to coral reef ecosystems. At the same time, this species is theorized to be expanding its range in the northwestern Pacific. Despite this, the current distribution of this species in Japan is unknown, with no research having been conducted since an initial assessment in 1984-1985. To address this information deficiency, a survey of the Ryukyu Archipelago from Amami Oshima Island south to the Yaeyama Islands was conducted to assess the distribution of T. hoshinota over the period of 2009 to 2011. Field images have been posted as an online image archive for researchers to utilize in future research. Our findings show that the presence of T. hoshinota is not uncommon in this region, with at least 23 of 64 (=36%) sites with this species. This is a considerable increase from levels reported in 1984-1985 (11 of 182 sites, =6%), and suggests this species is now a permanent feature in the coral reef ecosystems of this region. However, large outbreaks were at approximately the same levels as reported in 1984-1985. Most T. hoshinota were found in shallow (<5 m) depths, and abundance does not appear to be greatly influenced by seasons. It may be that general degradation of reefs in these decades has contributed to the spread of this species. Long-term monitoring and additional research are needed to assess the threat T. hoshinota poses to the coral reefs of southern Japan.

伊豆大島におけるトルコギキョウ株腐病, ブーバルジア苗立枯病 (新称) の発生と薬剤による防除

伊豆大島におけるトルコギキョウ株腐病, ブーバルジア苗立枯病 (新称) の発生と薬剤による防除

Characteristics and Factors of Long-term Return Migration of Old-time Residents of Ashiken Settlement Uken Village, Amami Oshima Island, Kagoshima Prefecture, Japan

Characteristics and Factors of Long-term Return Migration of Old-time Residents of Ashiken Settlement Uken Village, Amami Oshima Island, Kagoshima Prefecture, Japan

“Block-in-matrix” fabrics that lack shearing but possess composite cleavage planes: A sedimentary mélange origin for the Yuwan accretionary complex in the Ryukyu island arc, Japan

While melanges have been taken to be a significant component of accretionary complexes, the use of this term has been mostly descriptive, given the lack of consensus concerning their genesis. However, many workers have interpreted asymmetric shear fabrics in melanges as evidence of a tectonic origin (i.e., giving rise to tectonic melanges), in contrast to olistostromes, which are considered to be purely sedimentary in origin due (at least in part) to the lack of such shear fabrics. It is still uncertain whether accretionary processes include those that involve the intense shearing of lithologies along with, for example, the incorporation and entrapment of exotic blocks by muddy matrices during sediment deposition and deformation in axial deep-sea trench settings. Here, we argue that the so-called fabrics that characterize accretionary complexes are primarily sedimentary in origin and are distinct from shear fabrics represented by tectonic melanges. We also propose that, following their accretion, subsequent recycling of such oceanic materials is a common feature within evolving accretionary prisms. Lastly, we draw attention to the observation that D1 pressure-solution cleavage planes—notably widespread in the lower Cretaceous Yuwan complex, Amami Oshima Island, in the Ryukyu arc, SW Japan—are absent from the minor asymmetric shear structures that often characterize tectonic melanges. In contrast, we suggest that the Yuwan complex represents the effects of broadly symmetric flattening. This scenario is supported by our observation that the number of sedimentary and deformation events differs significantly compared to the single phase of shearing expected in tectonic melanges. D minus 1 (D −1 ) pressure-solution and axial-planar cleavages are only observed in exotic blocks and exhibit older accretionary deformation events within a preexisting accretionary prism. Of the existing structural associations, Sd1 is the oldest, predating the D −1 sedimentary episode, and it represents an sedimentary phase associated with the formation of a distinct type of block-in-matrix fabric produced by the accumulation of debris flows at seamount margins. Sd2 represents a succeeding sedimentary episode characterized by trench-axis debris flow, including inclusions derived from collapsed material from an older accretionary prism. The resulting Sd2 block-in-matrix fabric is one of the main lithologic components of the Amami Oshima Yuwan complex. Here, the Sd2 episode typically includes an igneous fabric, consisting of nonexotic intrusive and extrusive basalts within a terrigenous matrix, suggesting that the Yuwan prism may have also been associated with a trench-trench-ridge triple junction. D1 coaxial deformation is observed to overprint all of the episodes represented, although it has not destroyed or significantly sheared their respective fabrics, especially in regard to the main Sd2 block-in-matrix structures, which are therefore considered to represent original sedimentary structures.

Geographic Variation in Morphological Traits of the Large Japanese Field Mouse,Apodemus speciosus(Rodentia, Muridae), from the Izu Island Group, Japan

We investigated geographic variation in morphological traits of the large Japanese field mouse (Apodemus speciosus) from the Izu Island Group, Japan. There was sexual dimorphism in external characters and cranial measurements; hence, these were considered in subsequent analyses. There was geographic divergence in morphometric characters among populations of the Izu Island Group and Honshu. Mice from the Miyakejima Island and Niijima-Shikinejima Islands differed from those of other populations and from each other; Oshima Island mice also differed, but to a lesser degree. Mice from three populations from Honshu were similar to one another, and mice from Kozushima Island were more similar to those from Honshu populations than those from Izu Island Group populations. These results suggest that A. speciosus populations in the Izu Island Group may have had multiple origins. One possible hypothesis to explain these patterns of variation is that the Miyakejima, Niijima, and Shikinejima populations may share a relatively longer history of overseas dispersal, whereas the Kozushima populations may have experienced a recent invasion from Honshu via human activities.

Identification of Bitter Constituents from Angelica keiskei KOIDZUMI

Laserpitin (LAS), isolaserpitin (ILA) and (8S,9R)-8-angeloxy-8,9-dihyrooroselol (DHO) were identified as bitter constituents from Angelica (A.) keiskei KOIDZUMI, which is becoming popular as vegetables and dietary supplements in Japan. A yellow juice from the aerial parts of 140 samples of A. keiskei could be grouped into 4 types (Type A∼D) according to the HPLC profiles with the peaks of bitter constituents. Type A was from the Hachijyo island strain, which detected LAS and ISO, and Type B was from the Oshima island strain, which only detected DHO. The LAS, ILA and DHO contents were 0.066∼0.092%, 0.040∼0.068% and 0.064∼0.279%, respectively.

Prediction of volcanic eruptions by pseudoanalytic functions

The imminent Oshima large volcanic eruption in Oshima Island near metropolitan Tokyo, Japan was successfully predicted by a practical method of modeling and numerical simulation. The event showed the same tendency against earth tides with a possible 2023-June-6-Mid-Europe-Gaigantic earthquake and 2042-August-6-Biscay-Alps-Black-Sea-Trech-Gigantic earthquake. Huge and large earthquakes and volcanic eruptions were triggered by their peculiar effective earth tides. The event scrutinized here fully acted as plate tectonics and a mathematical model, as viscoelastic fluid phenomena. At the first stage of the simulation, an elastic-viscoplastic porous medium replaced the actual geologic structure, and then conventional theories for random signals and noises determined the most possible vent of eruption. At the next stage, the temporal three-dimensional pseudoanalytic function solver gave the dynamical simulation of the event in Oshima Island. An integrated procedure of direct and indirect solvers minimized variety types of inevitable ambiguities in the modeling and numerical simulation. The event was given in minute order and in Japan Standard Time.

B39 伊豆大島の3次元磁気構造と1986年噴火以降の地磁気変化(火山の物理(2),日本火山学会2006年秋季大会)

B39 伊豆大島の3次元磁気構造と1986年噴火以降の地磁気変化(火山の物理(2),日本火山学会2006年秋季大会)

Who expects the municipalities to take the initiative in tourism development? Residents’ attitudes of Amami Oshima Island in Japan

Regional tourism policies in Japan have been undergoing major structural changes. Meanwhile, smaller municipalities in Japan face challenges with respect to their relationships with neighboring municipalities, prefectures and the central government. This study highlights a number of significant features for the roles and relationships of the central government, prefectures and municipalities in tourism policy. It uses the example of investigating the extent to which residents of the Amami Oshima Islands expect their municipality to take the initiative in implementing or financing tourism development policies. A binary choice approach is used to model individual survey responses in terms of respondents’ socio-economic characteristics. Residents who expect the municipality to promote tourism and industrial development have a significantly different socio-economic status. Respondents most likely to expect the municipality to take the lead in policy making include executive officers or employees of private companies, the unemployed, the self-employed, or part-time workers. Government employees are not likely to have this expectation. In terms of the funding authority, the likelihood that a resident expects the municipality to take an industrial development initiative increases as the annual income per resident increases.

Reproduction of Ishikawa's frog on Amami Oshima Island

Reproduction of Ishikawa's frog on Amami Oshima Island

Age and growth of yellowstriped butterfish, Labracoglossa argentiventris, around Izu Oshima Island

Age and growth of the yellowstriped butterfish, Labracoglossa argentiventris, around Izu Oshima Island were studied using a total of 1450 fish. Age was determined by counting the edge of the opaque zones as a ring mark on sectioned sagittal otoliths. Formation of the first ring was observed during spring or summer, corresponding to 1.5 years after hatching. Thereafter, one ring was formed each year in the same season as the previous year. The growth of the butterfish was rapid until 2 years of age. The maximum likelihood method was applied to the age and length data for estimating parameters in von Bertalanffy, Gompertz, and Logistic growth models. The selected model, based on the Akaike Information Criterion, was the von Bertalanffy growth model, which indicated differential asymptotic length and variance by sex.