Search

The taxonomic status of the now likely extirpated Korean Peninsula wolf has been extensively debated, with some arguing it represents an independent wolf lineage,Canis coreanus. To investigate the Korean wolf genetic affiliations and their taxonomic implications, we sequenced and analysed the genomes of a historical Korean wolf dated to the beginning of the 20th century, and a captive wolf originally located at the Pyongyang Central Zoo. Our results indicated that the Korean wolf bears similar genetic ancestry to other regional East Asian populations, therefore suggesting it is not a distinct taxonomic lineage. We identified regional patterns of wolf population structure and admixture in East Asia with potential conservation consequences in the Korean Peninsula and on a regional scale. We find the Korean wolf has similar diversity and inbreeding to other East Asian wolves. Finally, we show that, in contrast to the historical sample, the captive wolf is more genetically similar to wolves from the Tibetan Plateau, hence, Korean wolf conservation programs might not benefit from the inclusion of this specimen.

With the ongoing COVID-19 pandemic, several previous studies from different countries showed that physical activity (PA) decreased during the COVID-19 outbreak. However, few studies have examined the recent tendency of PA in the adolescent population. Thus, we aimed to investigate the long-term trend of PA in Korean youth and the prevalence changes between before and during the COVID-19 pandemic.Data from Korea Youth Risk Behavior Web-Based Survey (KYRBS) was collected for consecutive years between 2009 and 2021. The period was separated into pre-pandemic (2009-2019), early-pandemic (2020), and mid-pandemic (2021). Self-reported amount of PA was categorized into four groups (insufficient, aerobic, muscle strengthening, and both physical activities) according to World Health Organization PA guidelines.A total of 840,488 adolescents aged 12-18 who fully responded to the survey were selected (response rate: 95.2%). The 13-year trends in the proportion of adolescents who reported aerobic and muscle-strengthening activities met or exceeded 2020 WHO exercise guidelines for adolescents plateaued (11.9% from 2009-2011, 14.2% from 2018-2019, 14.4% from 2020, and 14.0% from 2021); however, the slope decreased during the pandemic (βThrough a nationwide representative study, there was no significant difference with regard to the number of Korean adolescents who achieved the PA guidelines (pre-and-post-pandemic); however, the prevalence of recommended levels of PA needs to increase more based on the trend before the COVID-19 outbreak. The findings of this study suggest reinforcement of the importance of public health policies for Korean youths to be more physically active, especially during and after the pandemic. This article is protected by copyright. All rights reserved.

International audience; Background: Although smoking is classified as a risk factor for severe COVID-19 outcomes, there is a scarcity of studies on prevalence of smoking during the COVID-19 pandemic. Thus, this study aims to analyze the trends of prevalence of smoking in adolescents over the COVID-19 pandemic period. Methods: The present study used data from middle to high school adolescents between 2005 and 2021 who participated in the Korea Youth Risk Behavior Web-based Survey (KYRBS). We evaluated the smoking prevalence (ever or daily) by year groups and estimated the slope in smoking prevalence before and during the pandemic. Results: A total of 1,137,823 adolescents participated in the study [mean age, 15.04 years [95% confidence interval (CI) 15.03–15.06]; and male, 52.4% (95% CI 51.7–53.1)]. The prevalence of ever smokers was 27.7% (95% CI 27.3–28.1) between 2005 and 2008 but decreased to 9.8% (95% CI 9.3–10.3) in 2021. A consistent trend was found in daily smokers, as the estimates decreased from 5.4% (95% CI 5.2–5.6) between 2005 and 2008 to 2.3% (95% CI 2.1–2.5) in 2021. However, the downward slope in the overall prevalence of ever smokers and daily smokers became less pronounced in the COVID-19 pandemic period than in the pre-pandemic period. In the subgroup with substance use, the decreasing slope in daily smokers was significantly more pronounced during the pandemic than during the pre-pandemic period. Conclusions: The proportion of ever smokers and daily smokers showed a less pronounced decreasing trend during the pandemic. The findings of our study provide an overall understanding of the pandemic’s impact on smoking prevalence in adolescents. [MediaObject not available: see fulltext.]

Production of fresh water based on a renewable energy source is one of the most important global challenges for mankind due to ever-accelerating climate changes. Solar thermal evaporation shows promise for overcoming the water scarcity problem by utilizing solar energy, the most abundant and clean energy source. To enhance the performance of solar evaporators, interfacial solar evaporators have been introduced, which harness solar energy onto the water surface. To enable energy conversion and water evaporation at the interfaces of a solar evaporator, multi-scale heat and water transport have been investigated. Furthermore, various light-absorbing materials and system configurations have been studied to achieve the theoretical maximum performance. The fundamental physics of the interfacial solar evaporator, including thermal and water transport, and a broad range of interfacial solar evaporator devices in terms of the fabrication techniques and its structures are reviewed.

Organic–inorganic hybrid halide perovskite solar cells are promising for next-generation thin-film solar cells, demonstrating power conversion efficiency exceeding 25%. In particular, single-crystal perovskite materials are estimated to possess superior optoelectronic properties that can further enhance the efficiency. However, fabricating thin single-crystal perovskite for a light-absorber layer remains challenging. In this study, a 40-µm-thick single-crystalline MAPbBr3 perovskite is fabricated by inverse temperature crystallization (ITC) with a selective seed-transfer technique. By using a separate seed growth process and a seed-transfer process, a 16.23-mm2-large single domain high-quality single-crystalline MAPbBr3 perovskite can be grown without additional nucleation. The grown single-crystal MAPbBr3 exhibits a low surface roughness of 0.51 nm and low trap density of 7.61 × 108 cm−3. We also fabricate solar cells with single-crystalline MAPbBr3 using a glass substrate coated with SnO2 and indium-tin-oxide thin films. The single-crystal MAPbBr3-based solar cells demonstrate a power conversion efficiency of 4.31%.

A study on the flora of Geomun Oreum, designated as a UNESCO World Natural Heritage Site, was surveyed in 2019. Vascular plants in this area revealed 310 taxa belonging to 90 families, 210 genera, 279 species, one subspecies, 27 varieties, and three formas. The Geomun Oreum showed low mean annual temperature, but it was confirmed that the emergence of warm-temperate plant species and evergreen broad-leaved forests was prominent. These results were interpreted to be due to a great deal of precipitation, many frost-free days, and the difference between the highest and lowest temperatures depending on the geographical characteristics of Geomun Oreum. Geomun Oreum is evaluated as a relatively natural habitat given the limited access of visitors and management, but it was confirmed that Sedum tosaense, a critically endangered species of the rare plants designated by the International Union for Conservation of Nature, requires conservation plans in the area.

In this study, a numerical simulation of edge-defined film-fed growth (EFG) was performed to determine the appropriate capillary conditions for Ga2O3 melt. Meniscus and capillary rise were significantly influenced by the design of the die in the EFG system. The ratio of the seed crystal and die width was >0.73 for a die width of 4.4 mm. Narrower slit width resulted in higher capillary rise with longer process time compared with wider slit width. Under conditions consistent with the simulation results, highly crystalline (100) β-Ga2O3 single crystals were successfully achieved.

Solar cells that are semitransparent and highly efficient can find diverse applications in automobile windows, building walls, and wearable devices. Here, we present a semitransparent perovskite thin-film solar cell with an Ag nanogrid transparent electrode, where electrospun poly(ethylene oxide) (PEO) nanofibers are used as an etching mask. Directional electrospinning has allowed us to obtain a grid-shaped electrode of well-aligned Ag nanogrids. The performance of transparent electrodes can be controlled by the electrospinning conditions and the choice of substrate materials. We theoretically analyze the transmittance and sheet resistance of the electrode. Furthermore, transferable Ag nanogrid transparent electrodes are fabricated on poly(dimethylsiloxane) (PDMS) substrates for application in semitransparent perovskite solar cells. Using an electrode that shows a high transmittance (92.7%) with a low sheet resistance (18.0 Ω·sq-1), a semitransparent perovskite thin-film solar cell demonstrates average visible wavelength transmittance, power conversion efficiency, and light utilization efficiency rates as high as 25.2, 12.7, and 3.21%, respectively.

Two-step growth of κ-Ga2O3 thin films on 4H-SiC substrates was attempted with temperature-varied buffer layers via mist chemical vapor deposition. The first-step Ga2O3 buffer layers affect the phase formation and grain size variation depending on growth temperatures. In the second-step thin-film growth, the κ-Ga2O3 thin film was grown at a fixed temperature of 500 °C regardless of various buffer layers. Three zones, namely, amorphous, κ phase, and mixed phase, were categorized in the κ-Ga2O3 thin films according to the buffer growth temperature. High-quality and smooth κ-Ga2O3 thin films could be achieved through the grain growth competition and slight buffer temperature variation in the two-step growth.

In the past, most of nuclear power plants in the world were constructed with 30 or 40 years of design-life. But some nuclear power plants are still operating beyond their design lives through regulatory permission to extend its operation. To extend designlife of nuclear power plant, it needs additional design and replacement for equipment and piping. It has also to meet the regulatory requirements under the approval of the regulatory body. Therefore, the original design life of 60 years has been applied to safety class 1 equipment and piping of some nuclear power plants. One of the methods to confirm whether safety class 2&3 equipment and piping can also operate up to 60 years is to perform the fatigue evaluation based on ASME B&PV Code. In consideration of the effects of load increase by extending their lifespan from 40 to 60 years, the equipment and piping should be evaluated the structural integrity by performing the heat transfer analysis and structural analysis. In this paper, the fatigue evaluation for the Safety Class 2 FW piping with 40-year design life was performed based on Subsection NB/NC of ASME B&PV Section III and Reg. Guide 1.207 to show that its fatigue integrity can be secured under 60-year operation even in the PWR environmental conditions.

Solar thermal distillation is a promising way to harvest clean water due to its sustainability. However, the energy density of solar irradiation inevitably demands scalability of the systems. To realize practical applications, it is highly desirable to fabricate meter-scale solar evaporator panels with high capillary performance as well as optical absorptance using scalable and high-throughput fabrication methods. Here, we demonstrate a truly scalable fabrication process for a bi-facial solar evaporator with copper oxide dendrites via the hydrogen bubble templated electrochemical deposition technique. Furthermore, we construct a theoretical model combining capillarity and evaporative mass transfer, which leads to optimal operation conditions and wick characteristics, including superhydrophilicity, extreme capillary performance, and omni-angular high optical absorptance. The fabricated porous surfaces with excellent capillary performance and productivity provide a pathway toward a highly efficient bi-facial solar evaporator panel with meter-level scalability.

The explosive increase in the number of IoT devices requires various types of communication methods. This paper presents secure personal authentication using electrostatic coupling Intra-body communication (IBC) based on frequency shift keying (FSK) and error correction. The proposed architecture uses GPIO for a transmitter and analog-to-digital conversion (ADC) for a receiver. We mplemented FSK modulation, demodulation, data protection, and error correction techniques in the MCU software without applying hardware devices. We used the characteristic that the carrier signal is 50% duty square wave for 1-bit error correction and applied a method of randomly inverting SHA1 hash data to protect user authentication data during transmission. The transmitter modulates binary data using a square wave as a carrier signal and transmits data through the human body. The receiver demodulates the signal using ADC and decrypts the demodulated binary data. To determine the carrier frequency from ADC results, we applied a zero-crossing algorithm which is used to detect edge characteristics in image processing. When calculating the threshold value within the zero-crossing algorithm, we implemented an adaptive threshold setting technique utilizing Otsu&rsquo, s binarization technique. We found that the size of the electrode pad does not affect the signal strength, but the distance between the electrode pad and the skin has a significant effect on the signal strength. Our results show that binary data modulated with a square wave can be successfully transmitted through the human body, and, when 1-bit error correction is applied, the byte error rate on the receiver side is improved around 3.5% compared to not applying it.

The influence of anion composition on the electrical characteristics of amorphous zinc-oxynitride thin-film transitors (TFTs) is investigated and quantitatively modeled, with emphasis on the subgap density of states (DOS). As the ratio of N to (N + O) increases, the density of valence band tail states increases, followed by narrowing of the bandgap and a decrease in the density of conduction band tail states, which in turn is followed by either a higher field-effect mobility or a better subthreshold swing; each of these effects is explained. Furthermore, the anion composition dependence of the transconductance degradation at a high bias is analyzed on the basis of the proposed model. In addition, the effects of the N/(N + O) ratio on carrier density and field-effect mobility are quantitatively explained by the ionized nitrogen vacancy ( ${V}_{\text {N}}^{{1.3}+}$ ) model observed in shallow donor peak in the DOS and by the charge-controlled mobility model, respectively. Finally, the effect of nanocrystalline structure mixed with amorphous on transport properties is discussed.

본 연구는 일반 성인을 대상으로 고통 감내력이 주관적 안녕감에 미치는 영향을 검증하고, 고통감내력과 주관적 안녕감의 관계에서 경험회피의 매개효과를 알아보고자 하였다. 이를 위해 2015년 10월 21일부터 24일까지 전국의 일반 성인 285명을 대상으로 온라인 설문조사를 실시하였다. 고통 감내력 부족 척도, 주관적 안녕감 척도, 수용 행동 질문지로 설문지를 구성하였고, 온라인조사 전문업체에 의뢰하여 설문지를 배포 및 회수하였다. 수집한 자료는 구조방정식 모형을 통하여 분석하였다. 분석결과, 고통 감내력은 주관적 안녕감과 정적 상관을 보였고, 경험회피와는 부적 상관을 보였으며, 주관적 안녕감과 경험회피는 부적 상관을 나타냈다. 또한 고통 감내력과 주관적 안녕감의 관계에서 경험회피의 매개효과를 검증한 결과, 경험회피는 유의한 수준에서 고통감내력과 주관적 안녕감의 관계를 부분 매개하는 것으로 나타났다. 마지막으로 간접효과의 검증을 위하여 편향수정 Bootstrapping을 실시한 결과, 고통 감내력이 경험회피를 거쳐 주관적 안녕감으로 가는 매개효과가 통계적으로 유의한 것으로 나타났다. 즉, 일반인의 고통 감내력이 주관적 안녕감에 직접적인 영향을 미치면서 동시에 경험회피를 통해 간접적으로도 영향을 미치는 것을 알 수 있다. 마지막으로 본 연구의 의의, 제한점 및 추후 연구를 위한 고려사항에 대해 논하였다.

Sialolithiasis, the most common salivary gland pathology, is caused by calculi in the gland itself and its duct. While patients with small sialoliths can undergo conservative treatment, those with standard-size or larger sialoliths require sialolithotomy. In the present case study, we removed two sialoliths located beneath the mucosa in the posterior and anterior regions of Wharton's duct, respectively. For the posterior calculus, we performed sialolithotomy via an intra-oral approach; thereafter, the small anterior calculus near the duct orifice was removed by hydraulic power. This method has not previously been reported. There were no complications either during the operation or postoperatively, and the salivary function of the gland remained normal.