Background: Visual–gait coupling, in which saccadic eye movements regulate the body’s center of mass (CoM), is fundamental for maintaining dynamic stability. However, previous research has primarily focused on optic flow or dual-task paradigms, leaving the specific influence of parameterizing saccadic visual demands during self-paced locomotion insufficiently explored. Objects: This study investigated how saccadic visual stimulation, varying in direction (horizontal vs. vertical [VT]) and frequency (0.5 vs. 1.1 Hz), modulates spatiotemporal gait characteristics and CoM-based dynamic stability during self-paced walking on a curved non-motorized treadmill. Methods: Twenty-five healthy young adults walked for 30 seconds at a comfortable selfselected pace on a curved non-motorized treadmill under four visual conditions: forward gaze, horizontal saccades at 0.5 Hz, VT saccades at 1.1 Hz, and horizontal saccades at 1.1 Hz. Gait parameters were recorded with inertial sensors and synchronized insoles, and CoM parameters were derived from inertial measurement unit-based segment kinematics. Results: Gait speed, cadence, and stride length were greatest during horizontal saccades at 1.1 Hz, whereas stride time was longest under forward gaze (p < 0.05). Mediolateral (ML) and VT CoM displacements, as well as CoM path length, were significantly larger under horizontal 1.1 Hz compared with forward gaze and VT saccades, indicating amplified postural demands (p < 0.05). Stance duration decreased and swing duration increased during horizontal 1.1 Hz saccades (p < 0.05). Conclusion: Saccadic visual stimulation reorganized propulsion–stability balance during selfpaced walking in a direction- and frequency-specific manner, indicating the need to consider both factors when developing visuomotor gait training strategies to enhance ML control without compromising progression.

This study investigated the spatiotemporal variation of fish larvae assemblages and their relationships with environmental factors in the coastal waters of Saryang and Yokji Islands, Korea, from June 2024 to April 2025. During the study period, surface water temperature ranged from 6.1 to 30.3°C and salinity ranged from 28.25 to 33.96 psu, showing clear seasonal variability. A total of 23 fish larvae taxa belonging to 5 orders and 14 families were identified. Dominant taxa included Parablennius yatabei, Engraulis japonicus, Sebastiscus marmoratus, and Hexagrammos agrammus. Larval abundance ranged from 15 to 1,137 ind. 1,000 m-3, with the highest density and species diversity observed in early summer. Cluster analysis revealed three seasonal assemblages: summer-autumn, winter, and winter-spring groups. Redundancy analysis (RDA) indicated that temperature, salinity, and several copepod taxa were associated with fish larvae distribution, while the cumulative variance explained by the first two axes was 23.9%. These results suggest that fish larvae assemblages in the Saryang and Yokji Islands coastal area are partly related to seasonal environmental gradients and zooplankton composition, but are also influenced by multiple factors including hydrodynamic transport and coastal physical structures. This study provides baseline ecological information on seasonal fish larvae assemblages in a multiisland coastal system and highlights the ecological importance of this area as a spawning and nursery ground for coastal fish populations.

This study examined the spatiotemporal distribution and community structure of fish larvae in the coastal waters of Geoje Island, Korea, from June 2024 to April 2025, and assessed the impact of environmental factors on larvae assemblages. The abundance of fish larvae varied significantly, ranging from 63 to 12,330 individuals per 1,000 m3. A total of 20 taxa from 14 families and 6 orders were identified. Dominant taxa included Clupea pallasii, Parablennius yatabei, Hexagrammos agrammus, Engraulis japonicus, Sebastiscus marmoratus, Sebastes schlegelii, Repomucenus valenciennei, and Rudarius ercodes. Cluster and nMDS analyses identified three distinct seasonal assemblages: a summer-autumn assemblage, a transitional assemblage, and a winter-spring assemblage. The summer-autumn assemblage was dominated by coastal and pelagic species, including Engraulis japonicus and Parablennius yatabei, while the winter-spring assemblage was characterized by coldseason spawning species such as Clupea pallasii and Hexagrammos agrammus. Redundancy analysis (RDA) revealed that temperature and salinity were the primary environmental drivers of fish larvae assemblages (p<0.01). Temperature was strongly correlated with Axis-1, which represents the main environmental gradient influencing larvae assemblages. Additionally, the copepod Acartia omorii showed a strong association with Axis-2, indicating that zooplankton community composition played a secondary role in shaping larvae assemblages. Environmental variables accounted for 26.3% of the total variance, suggesting that larvae distributions were affected by environmental conditions, hydrodynamic transport, spawning strategies, and biological interactions. These findings provide essential baseline information for fisheries resource management and coastal ecosystem monitoring.

Understanding the distinct hydro-biogeochemical dynamics of lotic and lentic systems is crucial for integrated watershed management, particularly in regions with complex land-use patterns. This study investigated the spatiotemporal water quality variations in Gunsan City, Republic of Korea. Monthly monitoring was conducted at 17 sites (8 rivers and 9 reservoirs) from May 2024 to May 2025 to analyze 11 physicochemical parameters. Multivariate statistical approaches, including Factor Analysis of Mixed Data and K-means clustering, were employed to elucidate the interactions between water body types and seasonal factors. Factor analysis identified two primary gradients explaining 42.7% of the total variance: anthropogenic nutrient loading (Axis 1) and seasonal metabolic-physical drivers (Axis 2). The study revealed distinct spatial heterogeneity; rivers exhibited significantly higher electrical conductivity and nutrient concentrations (e.g., TN, TP) compared to reservoirs, clustering into a high-pollution group driven by point and non-point sources. Seasonally, rivers showed a marked concentration effect during the dry winter season due to reduced base flow, whereas reservoirs maintained relatively stable water quality attributed to the dilution capacity of larger water volumes. Shallow reservoirs like Backseokje exhibited characteristic water quality pattern, such as hypoxia related to organic matter decomposition and high vegetation cover. These findings suggest that a differentiated management approach is essential: mitigating point-source and non-point-source pollution and securing base flow for rivers during dry seasons, while regulating internal biogeochemical processes and inflows for reservoirs.

전라남도 해남군 두륜산도립공원은 난온대림과 온대림의 경계에 있는 추이대로 기후변화에 민감하게 반응하는 지역 이다. 본 연구는 랜드셋(Landsat) 위성영상과 딥러닝(deep learning) 기법을 활용하여 두륜산도립공원의 식생을 분류하 고, 지난 40년간 난온대 상록활엽수림의 공간분포 변화 특성을 분석했다. 분석 결과, 상록활엽수림 면적은 1980년대 중반 143.2ha(4.3%)에서 2020년대 중반 191.0ha(5.8%)로 증가하였다. 특히 이 분포 범위는 특정 지형 조건에 국한되지 않고, 고도·경사·사면향·토양 조건이 서로 다른 다양한 환경으로 확대되는 양상을 보였다. 이러한 결과는 상록활엽수림 이 단순히 면적 증가를 넘어, 기존의 환경적 제약을 점진적으로 극복하며 생태적 지위를 확장해 왔음을 의미한다. 본 연구는 난온대 상록활엽수림의 공간적 확장을 정량적으로 제시함으로써, 기후변화에 대한 식생 반응을 이해하는 데 중요한 기초자료를 제공한다. 두륜산 사례는 난온대림의 장기적인 분포 변화를 예측하고, 도립공원을 포함한 자연공 원의 식생 보전·관리 전략 수립에 중요한 시사점을 제공한다.

Background: In mammals, DRP1 is a key regulator of mitochondrial fission during mitochondrial dynamics, whereas ATF5 promotes the mitochondrial unfolded protein response (UPRmt). Both pathways are essential for maintaining cellular homeostasis and protecting oocytes and embryos from external stressors. However, the relationship between ATF5 expression and DRP1 under heat stress conditions during porcine oocyte maturation remains unclear. Methods: In this study, we investigated the mitochondrial dynamics and ATF5 expression in porcine oocytes exposed to heat stress during in vitro maturation (IVM). Protein and gene expression levels were assessed using immunofluorescence staining, Western blotting, and quantitative PCR. Results: During IVM, both DRP1 and ATF5 expression were increased (p < 0.01) significantly. In contrast, heat stress markedly impaired (p < 0.05) meiotic progression and cumulus cell expansion. Mitochondrial dynamics were disrupted (p < 0.05), as fission and fusion markers displayed reciprocal changes relative to those in controls. Concomitantly, the expression of ATF proteins was significantly reduced (p < 0.01) under heat stress. Heat-stressed oocytes also exhibited decreased (p < 0.05) expression of genes involved in antioxidant defense and NAD metabolism, whereas autophagy- and apoptosis-related transcripts were significantly upregulated (p < 0.05). At the blastocyst stage, embryos derived from heat-stressed oocytes exhibited nuclear localization of the UPR-associated transcription factors ATF4, CHOP, and ATF5. Conclusions: Collectively, our findings suggest that heat stress disrupts mitochondrial dynamics and ATF5 expression during porcine oocyte maturation while the UPRmt pathway remains active during early embryonic development to mitigate heat-induced cellular damage.

The molecular dynamic simulation method is usually used to analyse microscopic fluid fields. To use this method in engineering problems with real scales of molecules needs more time and greater computer power than we have now. To overcome these limitations, the expansion method using dimensionless and similarity of physical quantities of molecules is studied and introduced for the engineering scale fluid dynamics.

As the impacts of climate change become increasingly pronounced, the role of ecosystems as sinks for atmospheric greenhouse gases has become increasingly important. In particular, wetlands have gained attention due to their high carbon storage capacity relative to their area. This study aimed to compare soil carbon storage and soil respiration between riverine wetlands and forest wetlands in Korea, and to identify key environmental factors influencing these processes. Seasonal surveys were conducted on the soil physical and chemical properties, carbon storage, and soil respiration in two riverine wetlands in the Geum River basin and one forest wetland in Goheung, Jeollanam-do. The analysis showed that the forest wetland stored 425.08±167.32 kg m-2 of carbon, approximately 26 times more than the 101.09±103.56 kg m-2 stored in riverine wetland soils. The forest wetland exhibited slow hydrological flow and low bulk density, creating conditions favorable for organic matter accumulation. Soil respiration measurements showed values of 0.31±0.28 gCO2 m-2 hr-1 in the riverine wetlands and 0.83±0.58 gCO2 m-2 hr-1 in the forest wetland, with no statistically significant difference between the two. Correlation analysis revealed a significant positive relationship with soil temperature (p<0.05) in both wetland types, indicating that temperature is an important factor regulating soil respiration. Additionally, total phosphorus was identified as a key factor in riverine wetlands, whereas pH was a major influencing factor in the forest wetland.

This study explored the population dynamics of the endangered perennial plant Pterygopleurum neurophyllum (Maxim.) Kitag through a multi-year winter deadbiomass removal approach. In 2022, a total population census was conducted at Wondong Wetland (Yangsan, Korea), where seven spatially independent patches were identified (P-1 to P-7). From 2023 to 2025, winter dead-biomass removal was implemented in two of these patches (P-1 and P-2), while the remaining patches served as controls. Annual population counts were monitored, and the effects of winter dead-biomass removal over time were analyzed using a generalized linear mixed model (GLMM) with a Poisson distribution. The interaction between management and year was highly significant (Wald χ 2=103.93, p<0.001), indicating differing temporal trajectories between the removal and control populations. No significant management effect was observed in 2023; however, the removal plots demonstrated a dramatic increase in 2024 (EMMs: Control=5.05 vs. Removal=92.77), which continued in 2025 (3.89 vs. 104.99). These findings indicate that winter dead-biomass removal significantly promotes the population expansion of P. neurophyllum, with ecological responses emerging cumulatively rather than immediately. This study provides empirical evidence that repeated winter dead-biomass removal, rather than a single-year disturbance, is crucial for the restoration and conservation of endangered wetland plant species.

자갈해빈의 특징 중의 하나는 자갈 입도의 측방 세립화이다. 이러한 자갈 크기의 점진적인 감소는 다양한 기작 으로 설명되고 있지만 여전히 논쟁 중이다. 남해안의 대표적인 자갈해빈으로 알려진 완도군 정도리 해빈을 대상으로 자 갈의 측방 세립화에 있어 입도와 형태의 조절에 대해 살펴보았다. 이를 위해 100 정점에서 직접측정 방식으로 입도와 형태분석을 하였다. 이러한 입도자료를 바탕으로 자갈의 이동 과정을 파악하기 위해 EMA 분석을 수행하였다. 정도리 자갈해빈은 남쪽으로 개방된 만입형으로서 동-서 방향으로 800m에 걸쳐 다양한 크기와 형태의 자갈로 이루어져 있다. 정도리 해빈은 지형 단차에 따라 현재 파랑의 영향을 받는 하부 자갈해빈과 고도 6-10m에 위치한 안정된 상부 자갈해 빈으로 구분된다. 해빈 지형측량 결과, 고도 4.7, 5.3 m에 각각 힌남노와 볼라벤 태풍범이 발견된다. 자갈 입도분석 결 과, 해빈의 동측에서는 –7 phi 이상의 거력-큰 왕자갈이 우세하고, 서측방향으로 잔자갈이 증가하며, 자갈의 평균입도는 –5.5 phi 이하로 뚜렷한 측방 세립화를 보인다. EMA분석 결과 5개의 EM으로 구분되며, 각각 공간적 분포 차이를 나 타낸다. 동측의 가장 큰 –7.1 phi 최빈값을 갖는 자갈 집단은 폭풍시에만 이동하는 잔류자갈로 해석되며, –5.8- –6.6 phi 범위의 중간 크기 자갈 집단은 해빈의 중앙에서 배경값 자갈과 혼합되다가, 넘어뜀을 동반한 분급과정을 거쳐 서측 에서 하나의 우세한 모드로 나타난다. 자갈 형태는 동측에서 서측 방향으로 뚜렷한 구형 자갈의 증가를 보인다. 연구지 역에서 나타난 자갈 입도의 측방 세립화는 큰 자갈의 잔류, 중간크기 자갈의 넘어뜀 현상에 따른 혼합과 분급으로 설 명할 수 있다. 서측으로 자갈 크기의 감소와 함께 구형 자갈의 우세는 자갈 이동에 있어 형태의 중요성을 알려준다.

제어형 재배 시스템에서는 일반적으로 일정한 광이 주어지는 반면, 자연 환경에서 식물은 변동하는 광을 경험한다. 이러한 동적 광환경에 적응하기 위해서는 과잉 에너지를 소산하고 광저해를 줄이기 위한 광보호 기작, 특히 비광화학적 소광(non-photochemical quenching, NPQ)의 유연한 조절이 필요하다. 본 연구에서는 상추 (Lactuca sativa L. cv. Top Green)을 대상으로, 고광 노출의 빈도와 점진적 변화 정도가 다른 네 가지의 10시간 광 시나리오(광/암 반복 처리, 암기 회복을 동반한 장시간의 고광 처리, 단계적 증가–감소 처리, 그리고 단계적 처리의 세분화된 변형)를 이용하여 연속적으로 형광 반응을 측정하였으며, Y(II), Y(NPQ), Y(NO), NPQ, 전자전달률, 그 리고 실제와 이론적 Fo′값을 비교하여 광저해 정도를 평가하는 지표인 qPd등을 생육 시기별로 분석하였다. 광/암 반복처리는 PSII 효율의 점진적 감소를 초래하였고, 장시간 고광 처리에서는 광저해가 유발되어 암기 동안 부분적 으로 회복되었다. 단계적 광도 변화는 전자 전달을 촉진하고 광합성 효율을 높게 유지하였으며, 세분화된 단계적 별화는 광저해를 완화시켰으나 총 광량이 낮아 효율이 제한적이었다. 반응은 식물체 연령에 따라 달라, 어린 잎일수 록 NPQ 유도가 크고 광 조사 동안 더 높은 qPd를 유지했지만, Y(II)는 낮고 처리 후 Fv/Fm의 감소는 더 크게 나타났 다. 특히 qPd와 Fv/Fm은 항상 일치하지는 않았는데, 이는 두 지표가 각가 실시간 광보호와 누적된 광저해를 보완적 으로 반영함을 보여준다. 본 연구 결과는 광보호와 광저해 간의 균형이 광 시나리오와 식물체 연령 모두에 의해 강 하게 영향을 받음을 보여주며, 이러한 요인을 고려한 동적 광 제어 전략이 수직농장에서 에너지 효율성과 지속가능 성을 향상시킬 수 있음을 시사한다.

이 연구는 유튜브의 사용과 사용시간에 따라 정치참여 동학이 어떻게 나타나는지를 증명하고자 한다. 연구는 유튜브의 정치 참여적인 특성에 관한 선행 연구를 비판적으로 검토하여 변인과 연구가설을 설정하였다. 연구는 설문조사를 활용한 계량적인 연구방법론을 적용했다. 분석을 과 학적으로 시행하기 위해 연구에서는 유튜브 비사용자 집단, 라이트유저 집단, 헤비유저 집단 등으로 구분했다. 분석 결과, 첫째, 유튜브 사용에 따른 온라인과 오프라인 참여의 차이는 나타났다. 둘째, 유튜브 사용유형 에 따른 정치참여 유형별 차이 분석 결과는 온라인 관찰적 참여, 온라인 상호작용적 참여, 오프라인 비관습적 참여는 헤비유저 집단 > 라이트유 저 집단 > 비사용자 집단 순으로 참여 지향성이 강한 것으로 나타났다. 셋째, 시민 정치참여 유형별 회귀분석 결과는 오프라인 관습적 참여를 제외하고 유튜브 사용시간 변인이 중요한 변인임을 확인했다. 요컨대, 유 튜브 사용은 정치참여에 정(+)의 인과성이 있으며, 사용자 집단 중에서도 사용시간이 길수록 더욱 강한 정(+)의 인과관계가 있는 것으로 확인되었 다.

To reduce the transient pressure oscillations (hunting) in pilot valves used in control systems of nuclear power plants, this study investigates the effect of orifice angle design using computational fluid dynamics (CFD). A conical orifice geometry with a base radius of 1.25 mm and a length of 1 mm was modeled with varying angles (10°, 20°, and 30°). The models were analyzed using transient flow simulation in ANSYS CFX, applying a k-ω turbulence model to accurately capture near-wall flow characteristics. The results showed that larger orifice angles led to reduced pressure hunting, improving system stability. Additionally, velocity and pressure distributions demonstrated smoother flow and smaller fluctuations at higher orifice angles. The findings indicate that optimizing orifice angle is an effective strategy to suppress pressure hunting in pilot valve systems.