Earticle

The skew-normal distribution has gained widespread application across various domains due to its flexibility in modeling asymmetric data. However, accurately estimating its parameters-particularly the shape parameter-as well as those of its extended families such as the truncated or multivariate skew-normal distributions, remains a significant challenge. This paper presents a brief theoretical review of two primary parameter estimation methods: Maximum Likelihood Estimation (MLE) and Weighted Moment Estimation (WMM). For the MLE approach, we further investigate the effectiveness of reparameterization techniques in enhancing numerical stability. The advantages, limitations, and computational behavior of both methods are thoroughly examined. Results indicate that reparameterization substantially improves the stability of MLE, while WMM demonstrates superior performance in scenarios involving small sample sizes or high skewness. In contrast, MLE may underperform in complex or extreme data settings. These findings provide valuable guidance for researchers in selecting appropriate estimation strategies and lay the groundwork for the development of more robust estimation methods in future studies.

To elucidate the relative importance of ruderal (R), competitive (C), and stress-tolerant (S) plant strategies within an ecocultural context, Grime’s CSR model (1974) was applied to twenty plant species found in the coastal disturbed landscapes of Muan-gun, South Korea. These strategies not only reflect biological adaptation but also mirror long-standing human influences on the landscape, such as land use, traditional farming, and settlement patterns. Based on their dominant adaptive strategies, species were classified into three groups such as R, R/CR, and CR. Canonical Correspondence Analysis (CCA) showed that these species were closely associated with canopy height (CH), leaf dry matter content (LDMC), specific leaf area (SLA), and leaf dry weight (LDW), clustering primarily near the center of the primary axis. The dominance of ruderal and ruderal/competitive strategists reflects adaptation to frequent anthropogenic and environmental disturbances. Cerastium holosteoides var. hallasanense and Portulaca oleracea exhibited pure R strategies, while fifteen species, including Bidens frondosa and Erigeron annuus , followed R/CR strategies. Three species—Cirsium japonicum , Rubus idaeus var. microphyllus , and Rumex crispus — were categorized as CR strategists. These results highlight how ruderal plant presence serves as an ecocultural indicator of human-modified environments and niche differentiation under disturbance. The findings underscore the importance of integrating traditional ecological knowledge and cultural landscape perspectives into vegetation management and restoration strategies. Enhanced national support for localized ecological monitoring is essential for strengthening regional resilience and advancing ecoculturally informed land-use planning.

The effect of surfactant type on the physicochemical properties of skin lotion formulations was investigated by varying the ethanol and tea tree oil contents as well as the type and amount of surfactant. Dispersed droplet size, surface charge, surface tension, and viscosity were measured. Among the three surfactants tested, HCO 60 produced the smallest droplets. Increasing ethanol content resulted in opacity and larger droplet sizes. Increasing oil content converted transparent formulations with nanometer-sized droplets into opaque ones and reduced surface tension. Viscosity increased in the order OD 16 < TW 80 < HCO 60.

This study investigated sugar addiction behaviors of female college students, quantified them using a sugar addiction index, and compared their sugar intake and sugar reduction perception according to the degree of sugar addiction. The degree of sugar addiction was classified into four groups by indexing the number of ‘yes’ answers to the sugar addiction behavior questionnaire. General information on the degree of sugar addiction showed differences among the four groups only in body mass index, and sugar consumption habits showed higher scores from A to D, indicating higher consumption of sugary foods. Among sugary foods, the food with the highest frequency of consumption was carbonated beverages, and the foods with a significantly higher frequency of consumption as D progressed were beverages and snacks. Perception of the government's sugar reduction policy and experience with education and campaigns were highest in A and decreased as they went to D. The need for education on reducing sugar intake and the future consumption of reduced-sugar foods were both highly recognized. In conclusion, the sugar intake habits of the female students in this study were higher than the suspicion of sugar addiction, and the sugar intake was higher as the underweight rate increased, and the interest in or experience with reducing sugar intake was low, indicating that the degree of sugar addiction was severe. It is believed that sugar reduction education will continuously require practical programs that can be applied directly to diet while taking into account differences in the degree of sugar addiction.