Impact Assessment of Storm Surge and Climate Change-Enhanced Sea Level Rise on Atoll Nations: A Case Study of the Tarawa Atoll, Kiribati

The Pacific region consists of numerous Small Island Developing States (SIDS), one of the most vulnerable to flooding caused by compound effects of sea level rise (SLR) and storms. Nevertheless, individual studies regarding the impact assessment for SIDS, such as the low-lying Kiribati, remain scarce. This study assessed the impact of climate change-induced storm surge and SLR compounding effects on Tarawa, the most populous atoll of Kiribati, the largest coral atoll nation. It projected the impact using a combined dynamic surge and SLR model based on the IPCC AR5 RCP scenarios and 1/100 and 1/50 years return period storm events. This approach allows estimating the inundation scope and the consecutive exposed population by the end of the 21st century. The results of this study show that the pace of SLR is pivotal for Tarawa, as the sea level rise alone can claim more than 50% of the territory and pose a threat to over 60% of the population under the most intense greenhouse gas emissions scenario. Furthermore, most coasts on the lagoon side are particularly vulnerable. In contrast, the contribution of extreme events is generally minimal due to low wind speeds and the absence of tropical cyclones (TC). Despite this, it is clear the compound effects are critical and may inescapably bring drastic changes to the atoll nations by the end of this century. The impact assessment in this study draws attention to the social impact of climate change on SIDS, most notably atoll islands, and evaluates their adaptation potential

Multi-scale Simulation of Subsequent Tsunami Waves in Japan Excited by Air Pressure Waves Due to the 2022 Tonga Volcanic Eruption

The 2022 Hunga Tonga-Hunga Ha’apai eruption generated tsunamis that propagated across the Pacific Ocean. Along the coast of Japan, nearshore amplification led to amplitudes of nearly 1 m at some locations, with varying peak tsunami occurrence times. The leading tsunami wave can generally be reproduced by Lamb waves, which are a type of air-pressure wave generated by an eruption. However, subsequent tsunamis that occurred several hours after the leading wave tended to be larger for unknown reasons. This study performs multi-scale numerical simulations to investigate subsequent tsunami waves in the vicinity of Japan induced by air pressure waves caused by the eruption. The atmospheric pressure field was created using a dispersion relation of atmospheric gravity wave and tuned by physical parameters based on observational records. The tsunami simulations used the adaptive mesh refinement method, incorporating detailed bathymetry and topography to solve the tsunami at various spatial scales. The simulations effectively reproduced the tsunami waveforms observed at numerous coastal locations, and results indicate that the factors contributing to the maximum tsunami amplitude differ by region. In particular, bay resonance plays a major role in determining the maximum amplitude at many sites along the east coast of Japan. However, large tsunami amplification at some west coast locations was not replicated, probably because it was caused by amplification during oceanic wave propagation rather than meteorological factors. These findings enhance our understanding of meteotsunami complexity and help distinguish tsunami amplification factors

Molecular tumorigenesis of the skin

Skin tumors are supposed to develop through accumulations of genetic and/or epigenetic events in normal cells of the skin. Among them, we focus on common skin tumors, including benign, seborrheic keratosis, and malignant, squamous cell carcinoma and melanoma. Many important molecules have been detected on the molecular tumorigenesis of each of them to date, and some drugs targeted for their molecules have been already developed. We review updates on the molecular tumorigenesis of these tumors with our current works

Abrupt decrease of the population of a tiger beetle species, Cylindela elisae (Carabidae, Cicindelinae), in Tottori Sand Dunes, Honshu, Japan in 2017.

鳥取市鳥取砂丘オアシス周辺に営巣するエリザハンミョウの集団の保全に向けて2015 年から本種の成虫が発生する夏季に標識再捕法により当地での発生個体数を調査している。すでに結果を報告している2016 年までの調査に引き続き2017 年も同様の調査をおこなった。エリザハンミョウの成虫の消長は過去2年よりも早めに進行し，成虫は6月中旬に出現，7月中にはほぼ消失した。この間にマークできた総個体数は112（2015 年は304，2016 年は270）とこの3 年間で最も少なく， Jolly-Seber 法による個体数推定値はもっとも多かった調査日（6 月27 日）でわずか153 であった（2015 年は2,300個体，2016 年は1,460 個体）。この個体数は個体群を健全に維持するために必要とされる最小集団サイズ（MVP）として従来言われてきていた500（個体数変動の大きい動植物では10,000）を大幅に下回っており，危険な状態である。2017 年におけるエリザハンミョウ成虫の早期の出現と消失は2017 年の7 月の高温が，また，個体数の減少にもっとも寄与した要因としては2017 年の4～6 月の少雨が考えられる。 / As a consecutive series of surveys of the population size of a tiger beetle species, Cylindera elisae (Motschulsky 1859) at a site so-called“ Oasis” in the Tottori Sand Dunes, Tottori City, started in 2015 (Tsurusaki et al. 2016, 2017), we estimated population size of the same population of the same species also in 2017 by using a mark-recapture method. A total of 112 adults of C. elisae were individually marked during the summer in 2017 (304 and 270 adults in 2015 and 2016 surveys, respectively). The highest number of adults of C. elisae estimated by the Jolly-Seber method was only 153 recorded on 27 June 2017. This population size is much smaller than 500 which was the number formerly often said as the minimum viable population (MVP), to say nothing of 10,000 as the MVP for univoltine insects whose population size tend to be variable every year. 　It is probable that high air temperature of July in 2017 brought early emergence and disappearance of C. elisae in 2017. It is also likely that drought at “Oasis” area due to extremely low amount of precipitation from April to June in 2017 was the main factor for the marked decrease of population of this species in 2017. Some measure should be taken for the recovery of this population

Efficient energy transport in an organic semiconductor mediated by transient exciton delocalization.

Efficient energy transport is desirable in organic semiconductor (OSC) devices. However, photogenerated excitons in OSC films mostly occupy highly localized states, limiting exciton diffusion coefficients to below ~10-2 cm2/s and diffusion lengths below ~50 nm. We use ultrafast optical microscopy and nonadiabatic molecular dynamics simulations to study well-ordered poly(3-hexylthiophene) nanofiber films prepared using living crystallization-driven self-assembly, and reveal a highly efficient energy transport regime: transient exciton delocalization, where energy exchange with vibrational modes allows excitons to temporarily re-access spatially extended states under equilibrium conditions. We show that this enables exciton diffusion constants up to 1.1 ± 0.1 cm2/s and diffusion lengths of 300 ± 50 nm. Our results reveal the dynamic interplay between localized and delocalized exciton configurations at equilibrium conditions, calling for a re-evaluation of exciton dynamics and suggesting design rules to engineer efficient energy transport in OSC device architectures not based on restrictive bulk heterojunctions

A new concept of transforaminal ventral facetectomy including simultaneous decompression of foraminal and lateral recess stenosis : Technical considerations in a fresh cadaver model and a literature review

Percutaneous endoscopic surgery for the lumbar spine, which was established in the last decade, requires only an 8-mm skin incision and causes minimal damage to the paravertebral muscles ; thus, it is considered to be a minimally invasive technique for spinal surgery. It has been used to perform percutaneous endoscopic discectomy via two main approaches : the TF approach is a posterolateral one through the intervertebral foramen and can be done under local anesthesia ; the IL approach is a more traditional one through the interlaminar space and is difficult to perform under local anesthesia. Recently, these techniques have been applied for lumbar spinal stenosis (LSS), the TF method for foraminal stenosis under local anesthesia, and the IL method for central and lateral recess stenosis under general anesthesia. In this study, using a fresh human cadaver model, we performed simultaneous decompression of the lateral recess and foraminal stenosis at L4-5 using the TF approach. Computed tomography confirmed enlargement of the lateral recess and intervertebral foramen. This technique, which can be performed under local anesthesia, should benefit elderly patients with LSS and poor general condition due to multiple comorbidities. Finally, we introduce the concept of percutaneous transforaminal ventral facetectomy using a spinal percutaneous endoscope