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The diagonal squall line that passed through the Korean Peninsula on the 18 May 2020 was examined using wind data retrieved from multiple Doppler radar synthesis focusing on its kinematic and dynamic aspects. The low-level jet, along with warm and moist air in the lower level, served as the primary source of moisture supply during the initiation and formation process. The presence of a cold pool accompanying the squall line played a role in retaining moisture at the surface. As the squall line approached the Korean Peninsula, the convective bands in the northern segment (NS) and southern segment (SS) of the squall line exhibited distinct evolutionary patterns. The vertical wind shear in the NS area was more pronounced compared to that in the SS. The ascending inflow associated with the tilted updraft in the NS reached an altitude of 7 km, whereas it was only up to 4 km in the SS. The difference was caused by the strong descending rear flow, which obstructed the ascending inflow and let to significant updraft in the SS. [ABSTRACT FROM AUTHOR]

We investigated the source, maturity, and biodegradation of organic matter (OM) deposited at two core sites (PSG-02 and PSG-03) of the Pohang Basin by analyzing stable isotopic compositions of bulk organic matter and specific lipid molecules (n-alkanes). In contrast to the lack of substantial variations in bulk carbon isotopic compositions along core depths, a homologous series of saturated alkanes (C16 to C35) showed distinct carbon chain-length distribution between both core sites, having predominance in C20 to C25 for PSG-02 and C29 for PSG-03. Such variation may reflect the different geochemical properties of the deposited OM involved in gas generation. In this regard, various n-alkane indices, for example, carbon preference index (CPI), terrestrial/aquatic ratio (TAR), average chain length (ACL), natural n-alkanes ratio (NAR), percentage of aquatic plants (Pmar-aq), and pristane/phytane (Pr/Ph), were applied to understand the OM origins and depositional environments at both core sites. The contribution of thermally petroleum-derived OM is predominant in PSG-02, as shown by the low values of CPI (< 1) and NAR (< 0.6). Conversely, high values of ACL (> 29), TAR (> 2), low values of Pmar-aq (< 0.4) and Pr/Ph (∼1) may be associated with mixed contributions of marine and terrestrial OM sources in PSG-03. In addition, Pr/Ph ratios suggest that sedimentary diagenesis conditions such as maturity and redox condition should be different between both core sites. Our results highlight useful information regarding the geochemical properties of OM involved in gas generation in the Pohang Basin. This will help us better define accumulated gas systems and reduce the risk associated with future exploration efforts in this area. [ABSTRACT FROM AUTHOR]

This study investigated the nitrate dual isotopic compositions (δ15N NO3 and δ18O NO3) of water samples to trace nitrate sources in Lake Sihwa, which encompasses various land-use types (e.g., urban, industry, wetland, and agriculture). The biogeochemical interactions of anthropogenic nitrogen sources (e.g., soil, road dust, and septic water) were also evaluated through multiple pathways from terrestrial boundaries to the water column. Based on increased concentrations of dissolved total nitrogen (DTN; 3.1 ± 1.6 mg/L) after typhoon, the variation of element stoichiometry (N:P:Si) in this system shifted to the relatively N-rich conditions (DIN/DIP; 14.1 ± 8.1, DIN/DSi; 1.4 ± 1.8), potentially triggering the occurrence of harmful algal blooms. Furthermore, discriminative isotopic compositions (δ15N NO3 ; 4.0 ± 2.1 ‰, δ18O NO3 ; 6.1 ± 4.3 ‰) after the typhoon suggested the increased DTN input of anthropogenic origins within Lake Sihwa would be mainly transported from urban sources (76 ± 9 %). Consequently, the isotopic-based approach may be useful for effective water quality management under increased anthropogenic activities near aquatic systems. [Display omitted] • Nitrate isotopes indicated specific sources derived from multiple land-use groups. • Anthropogenic nutrient input after typhoon events further enriched N and P in lake Sihwa. • Urban-derived nitrate fraction significantly increased through heavy precipitation. [ABSTRACT FROM AUTHOR]

Background: Obesity affects health-related quality of life (QoL); however, their relationship among elderly Asians is not well known. Aims: Relationship of domain-specific QoL with body mass index (BMI) and waist circumference and the sex differences were investigated using a nationally representative sample of elderly Korean population. Methods: In the Korea National Health and Nutrition Examination Survey phase VII (2016–2018), 3659 adults aged ≥ 65 years (1551 men and 2108 women) participated. BMI and waist circumference were classified according to Asian- and Korean-specific criteria. QoL was evaluated using the European Quality of Life Scale-Five Dimensions (EQ-5D). Multivariable logistic regressions were used to examine the relationship of QoL with BMI and waist circumference. Results: Men with BMI < 18.5 kg/m2 and ≥ 25.0 kg/m2 had a significant association with poor QoL in mobility and self-care, but no relationship was found with the other domains. Women with BMI ≥ 25.0 kg/m2 had poor QoL in mobility and self-care, and those with BMI ≥ 30.0 kg/m2 had poor QoL in usual activities and pain/discomfort. There was no significant association with anxiety/depression. Both elderly men and women with abdominal obesity had a significant association with poor QoL in mobility, self-care, usual activities, and pain/discomfort; however, there was no significant relationship with waist circumference and anxiety/depression. Conclusions: The association between QoL and BMI was different according to sex and the domains of QoL. Domain-specific QoL should be considered in the management of body weight of the elderly. [ABSTRACT FROM AUTHOR]

Understanding the development of early states on the Korean Peninsula is an important topic in Korean archaeology. However, it is not clear how social structure was organized by these early states and what natural resources were utilized from their surrounding environments. To investigate dietary adaptation and social status in ancient Korea, stable isotope ratios and radiocarbon dates were measured from humans and animals from the Imdang cemetery, Gyeongsan city, South Korea. The results indicate that the Imdang diet was mainly based on C3 plants and terrestrial animals. Animal remains in the graves were directly consumed as daily food items as well as for ritual offerings. MixSIAR modeling results revealed that the dietary sources for the humans were: game birds > C3 plants > terrestrial herbivores > marine fish > C4 plants. The finding that the game birds represented the highest contribution to the whole diet, indicates that game birds must have been intensively hunted. Furthermore, elites consumed more game birds than their retainers and they also consumed seafood as a privileged dietary item in the Imdang society. This study demonstrates that the Apdok was a stratified society having high variations in the consumption of food items available to an individual and provides new insights about the subsistence and social status of the early ancient Apdok state on the Korean Peninsula. [ABSTRACT FROM AUTHOR]

This study aimed to examine the association between disability and cardiovascular (CV) disease incidence and mortality in Korea longitudinally, using a national representative sample. We used the National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS) database, which includes information on the disability of the National Screening Program participants such as severity and type of disability, which were obtained from the Korean National Disability Registry. Cox proportional hazard models were used to evaluate the association between disability and CV disease incidence and mortality. We constructed four models with different levels of adjustment, in which Model 3 was a fully adjusted model. This study included 514,679 participants, and 7,317 CV deaths were reported within a mean follow up of 10.8 ± 3.9 years (maximum, 13.9 years). For 5,572,130 person-year (PY) follow-up, the CV mortality rate was 1.313 per 1,000 PY. In Models 1 and 2, CV disease incidence was significantly higher in participants with disability than in those without disability. In Model 3, the incidence was higher only among participants aged 50–64 years and severe disabled participants aged <50 years. CV mortality was significantly higher in participants with disability than in those without disability in all Models, and the mortality increased in both sexes in Models 1 and 2 but only increased in men in Model 3. Similar results were observed in the subgroup analysis of health behavior and chronic diseases. People with disability showed higher CV disease incidence and mortality than those without disability, regardless of the type of disability or risk factors for CV disease. [ABSTRACT FROM AUTHOR]

Submarine groundwater discharge (SGD) is a global phenomenon that carries large volumes of groundwater and dissolved chemical species such as nutrient, metals, and organic compounds to coastal zones. We report the influence of SGD on the coastal waters of Jeju Island, Korea, using high-resolution aerial thermal infrared (TIR) mapping techniques and field investigations. An aircraft-based system was implemented using a cost-effective TIR camera for aerial TIR mapping. Ground-based calibrations and system integration with GPS/IMU (global positioning system/inertial measurement unit) were performed for the aerial systems. The aerial surveys showed distinct low-temperature signatures of SGD along the coasts of Jeju Island, revealing large groundwater inputs from the coastal aquifers to the ocean. Multiple aerial surveys over a range of seasons and tidal stages revealed that SGD rates dynamically affect the sea surface temperature (SST) of the coastal zone. The in-situ measurements supported that SGD has a substantial influence on the coastal water chemistry as well as SST. Our observations highlight the extent to which aerial-based TIR mapping can serve as a powerful tool for studying SGD and other coastal processes. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We investigated the composition, source, and reactivity of sedimentary organic matter (OM) present in aquaculture systems along the Korean coast. A multi-isotopic approach was applied to 216 surface sediments from five sections: western (W)-1, W-2, southern (S)-1, S-2, and eastern (E)-1 sections. The 15N-enriched total nitrogen signatures in the surface sediments of the W-1 section may indicate that a substantial fraction of sedimentary OM has anthropogenic origins exported through the Han River. Simultaneously, the deposition of allochthonous OM is predominant in the S sections (Jinhae and Masan Bays). The 34S-depleted patterns at the S-2 section may indicate that sulfate reduction occurring at the sedimentary boundary contributes to active OM decomposition, depending on the increased sedimentation of the aquaculture-derived OM. Our results highlight that isotopic-based source tracking near aquaculture systems provide important information for identifying anthropogenic contamination in coastal marine sediments and for improving environmental management. • Composition, source, and reactivity of sedimentary organic matter in aquaculture • The multi-isotopic approach was used to analyze surface sediments. • Isotopes tracks give insights into coastal sediment anthropogenic contamination. [ABSTRACT FROM AUTHOR]

Abstract: Leukaraiosis and a higher level of pulse pressure are well-recognized as associated with cardiovascular disease, vascular angiopathy, and geriatric syndrome. A cross-sectional study was conducted to examine the relation between pulse pressure and leukoaraiosis based on brain magnetic resonance imaging (MRI) scans in the apparently healthy elderly (147 men aged 60–84 years and 89 women aged 60–82 years). The odds ratios (OR) and 95% confidence interval (CI) for leukoaraiosis were calculated using multivariate logistic regression analyses according to each quartile of pulse pressure. The percentage of leukoaraiosis gradually increased in accordance with pulse pressure quartiles: 5.1%, 8.6%, 16.1%, and 26.2% for men, and 4.5%, 8.7%, 13.0%, and 23.8% for women. In comparison with subjects in the lowest quartile, the OR (95%CI) for leukoaraiosis in the highest quartile was 6.80 (1.20–38.45) in men after adjusting for age, body mass index, fasting plasma glucose, HDL-cholesterol, triglyceride (TG), smoking status, and current drinking. However, the relationship was not evident in women after adjusting for the same co-variables. In conclusion, pulse pressure was found to be independently associated with leukoaraiosis regardless of classical cardiovascular risk factors in elderly men. [Copyright &y& Elsevier]

• River systems have diverse POC sources along various land-use types. • An integrated framework is needed to figure out the quantitative contribution of POC sources. • Specific lipid biomarkers are useful to determine POC origins between natural and anthropogenic sources. • Hydrological models are effective in estimating variations in POC loads for water discharges. • The integrated approach allows to calculate the exact quantitative contribution of POC loads. Despite receiving a considerable amount of attention in the past, quantitative and systematic estimation of the source contributions for different organic carbons (OCs) in complex river systems is still challenging. In this study, we tested an integrated framework using field data of bulk elements and lipid biomarkers and hydrological modeling (hydrological simulation program FORTRAN, HSPF) for the quantitative estimation of OC loads along different land-use types of a watershed (Geumho River watershed in South Korea). Based on the specific source assignments identified from the lipid biomarker patterns in particulate organic carbon (POC) such as short/long chains of alkanes, fatty acids and alcohols, and coprostanol/cholesterol, spatial variations of the diagnostic lipids could be used as an indicator to discriminate between the contributions of natural (algae, bacteria, and terrestrial plants) and anthropogenic sources (fecal). Based on the integration of HSPF modeling, it was also found that various POC loads might be partially controlled by different water discharges within watersheds. With the increase in POC fluxes, the increase in fecal loads was also noticed, as reflected by the predominant lipid (especially coprostanol normalized by water discharges). As a straightforward approach, we developed a set of indices including fecal index-1, ratios of coprostanol, fatty acids, and alkanes, which strengthened the sensitivity for fecal contamination. Compared with the conventional HSPF results, the variations of these proposed indices were more influenced by the broadened watershed extents with increasing downstream distance, which provided a more accurate estimation of the quantitative contributions of POC loadings in the complex river system. [Display omitted] [ABSTRACT FROM AUTHOR]

The increasing global consumption of seafood has led to increased trade among nations, accompanied by mislabeling and fraudulent practices that have rendered authentication crucial. The multi-isotope ratio analysis is considered as applicable tool for evaluating geographical authentications but requires information and experience to select target elements such as isotopes, through a distinction method based on differences in habitat and physiology due to origin. The present study examined recombination conditions of multi-elements that facilitated geographically distinct classifications of the clams to sort out appropriate elements. Briefly, linear discriminant analysis (LDA) analysis was performed according to several combinations of five stable isotopes (carbon (δ13C), nitrogen (δ15N), oxygen (δ18O), hydrogen (δD), and sulfur (δ34S)) and two radiogenic elements (strontium (87Sr/86Sr) and neodymium (143Nd/144Nd)), and the geographical classification results of the Manila clam Ruditapes philippinarum from Democratic People's Republic of Korea (DPR Korea), Korea and China were compared. In conclusion, linear discriminant analysis (LDA) with at least four elements (C, N, O, and S) including S revealed a remarkable cluster distribution of the clams. These findings expanded the application of systematic multi-elements analyses, including stable and radiogenic isotopes, to trace the origins of R. philippinarum collected from the Korea, China, and DPR Korea. [ABSTRACT FROM AUTHOR]

• Source to estuary surveys revealed specific pollution and dam effects on river GHGs. • Pollution effects on riverine CO 2 , CH 4 , and N 2 O vary with source size and location. • Cascade weirs boost CH 4 production, offsetting CO 2 sinks in eutrophic river-estuary. • δ13C indicates wastewater-derived GHGs and temperature-enhanced CH 4 oxidation. • Basin-specific perturbations warn generalizing eutrophic river-estuary as C sinks. Large uncertainties exist regarding the combined effects of pollution and impoundment on riverine greenhouse gas (GHG) emissions. It has also been debated whether river eutrophication can transform downstream estuaries into carbon sinks. To assess human impacts on the riverine and estuarine distributions of CO 2 , CH 4 , and N 2 O, two source-to-estuary surveys along three impounded rivers in Korea were combined with multiple samplings at five or six estuarine sites. The basin-wide surveys revealed predominant pollution effects generating localized hotspots of riverine GHGs along metropolitan areas. The localized pollution effect was pronounced in the lower Han River and estuary adjacent to Seoul, while the highest GHG levels in the upper Yeongsan traversing Gwangju were not carried over into the faraway estuary. CH 4 levels were elevated across the eutrophic middle Nakdong reaches regulated by eight cascade weirs in contrast to undersaturated CO 2 indicating enhanced phytoplankton production. The levels of all three GHGs tended to be higher in the Han estuary across seasons. Higher summer-time δ13C-CH 4 values at some Nakdong and Yeongsan estuarine sites implied that temperature-enhanced CH 4 production may have been dampened by increased CH 4 oxidation. Our results suggest that the location and magnitude of pollution sources and impoundments control basin-specific longitudinal GHG distributions and estuarine carryover effects, warning against simple generalizations of eutrophic rivers and estuaries as carbon sinks. [Display omitted] [ABSTRACT FROM AUTHOR]