• Korean journal of applied entomology
• /
• v.60 no.4
• /
• pp.387-401
• /
• 2021

Thrips infesting hot peppers were monitored in greenhouses using yellow sticky traps. In addition, the hot peppers infected with tomato spotted wilt virus (TSWV) were observed during the monitoring period. The flower thrips (Frankliniella intonsa) were initially trapped at a low density just after transplanting seedlings of hot peppers at late March. The western flower thrips (Frankliniella occidentalis) were trapped after mid April. These two thrips represented more than 98% of the total thrips attracted to the traps after May, in which F. intonsa showed higher occurrence frequency than F. occidentalis. The total number of thrips had two peaks at mid May with a small and short-term peak and at June-July with a large and long-term peak. The trapped thrips exhibited inconsistent sex ratios, suggesting a seasonal parthenogenesis. Different geographical populations were varied in cytochrome oxidase I sequences, in which local populations in Andong shared a high sequence similarity. TSWV-infected hot peppers, which might be mediated by these two thrips species, were observed and confirmed by an immunoassay kit and a molecular diagnosis using RT-PCR. In addition, the TSWV was detected in F. occidentalis collected from the infected hot peppers. Three open reading frames (NS_S, N, and NS_M) of the isolated TSWV genomes were sequenced and showed multiple point mutations containing missense mutations among geographical variants. When the isolated TSWV was fed to nonvirulent thrips of F. occidentalis, the virus was detected in both larvae and adults. However, the viral replication occurred in larvae, but not in adults.

• 한국노년학
• /
• v.38 no.3
• /
• pp.551-567
• /
• 2018

Demographic and socio-structural information is useful to identify potential welfare recipients who are in need of disease-prevention and intervention services. Thus, the present study aims to explore the differences in grip strength among middle and old-aged adults by living conditions and by living area. The 5th wave data of Korean Longitudinal Study of Aging was utilized. The dependent variable was grip strength, and the independent variables were living alone (living alone or not) and living area (city or non-city). Covariates were age, education, log-transformed household income, spouse existence, body mass index, self-rated health conditions, depressive symptoms, cognitive function, smoking, regular exercise, frequency of meeting with friends, and the number of social participation. Regression analysis was performed for middle-aged men, middle-aged women, old-aged men, and old-aged women, respectively. ANOVA and Chi-test were additionally used to specifically discuss significant results. Cross-sectional weight was applied to all analyses. According to the results, living alone and living area did not have significant effects on grip strength among middle-aged men, old-aged men, and old-aged women. In middle-aged women, however, living alone and living area were significantly associated with grip strength. To be specific, middle-aged women who lived alone in rural areas had the lowest grip strength compared to other middle-aged women. Additional analysis showed that middle-aged women who lived alone in rural areas had risk factors, such as low education level, low income, or high depressive symptoms. It implies that middle-aged women living alone in rural areas may have physical health risks, so they might be in need of disease prevention. This study is meaningful in that it can provide reliable information on the latent welfare recipients by using representative panel data and applying weight values.

• Journal of the Korean Applied Science and Technology
• /
• v.36 no.2
• /
• pp.394-406
• /
• 2019

The cellular senescence may be due to damage by the reactive oxygen species (ROS). This study has compared the antioxidant activity in the human cell lines of various origins, including 10S and 50S-derived normal skin fibroblasts, and 10S bone marrow, dental tissue and adipose-derived adult stem cells. After being exposed to $H_2O_2$, half inhibitory concentration ($IC_{50}$) values by cytotoxicity assay was significantly (P<0.05) lower in 50S-derived skin fibroblasts, than in 10S-derived skin fibroblasts and various adult stem cell lines. The cell population doubling time (PDT) and the cell frequency with high senescence associated-${\beta}$-galactose activity were remarkably increased in 50S-derived fibroblasts exposed to 50 ppm $H_2O_2$ for 7 days, than those of 10S-derived fibroblasts and various adult stem cell lines. Further, the expression level of antioxidant-related genes, glutathione peroxidase (GPX) and catalase (CAT), was investigated in 10S and 50S-derived skin fibroblasts, and 10S-derived various adult stem cells by reverse transcription polymerase chain reaction (RT-PCR). The expression level of GPX was higher in most of cell lines, compared to CAT, and a significantly (P<0.05) higher expression level of GPX was observed in 10S-derived skin fibroblasts and adult stem cell lines, compared to 50S-derived skin fibroblasts. We concluded that old-aged skin fibroblasts seemed to be less resistant against ROS than young-aged skin fibroblasts and adult stem cells.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.31 no.3
• /
• pp.101-114
• /
• 2019

In this study, we carry out the numerical simulation to trace the yearly shoreline change of Mang-Bang beach, which is suffering from erosion problem. We obtain the basic equation (One Line Model for shoreline) for the numerical simulation by assuming that the amount of shoreline retreat or advance is balanced by the net influx of longshore and cross-shore sediment into the unit discretized shoreline segment. In doing so, the energy flux model for the longshore sediment transport rate is also evoked. For the case of cross sediment transport, the modified Bailard's model (1981) by Cho and Kim (2019) is utilized. At each time step of the numerical simulation, we adjust a closure depth according to pertinent wave conditions based on the Hallermeier's analytical model (1978) having its roots on the Shield's parameter. Numerical results show that from 2017.4.26 to 2017.10.15 during which swells are prevailing, a shoreline advances due to the sustained supply of cross-shore sediment. It is also shown that a shoreline temporarily retreats due to the erosion by the yearly highest waves sequentially occurring from mid-October to the end of October, and is followed by gradual recovery of shoreline as high waves subdue and swells prevail. It is worth mentioning that great yearly circulation of shoreline completes when a shoreline retreats due to the erosion by the higher waves occurring from mid-March to the end of March. The great yearly circulation of shoreline mentioned above can also be found in the measured locations of shoreline on 2017.4.5, 2017.9.7, 2017.11.7, 2018.3.14. However, numerically simulated amount of shoreline retreat or advance is more significant than the physically measured one, and it should be noted that these discrepancies become more substantial for the case of RUN II where a closure depth is sustained to be as in the most morphology models like the Genesis (Hanson and Kraus, 1989).

• Journal of Wetlands Research
• /
• v.20 no.4
• /
• pp.398-409
• /
• 2018

Organic farming practices including loach based ecosystem-farming have been demonstrated to be effective in conjunction with rice farming to increase yield and quality. This new form of farming combines agriculture and fishery and is quickly developing into a new industry. The current study investigated the effect of rice-fish mixed farming system on the vegetation-diversity function. Vegetation within the four study sites was surveyed and analyzed based on plant taxonomy. The vegetation survey demonstrated that 127 taxa of 38 families, 100 genera, 107 species, and 20 varieties occurred within the study sites. A total of 15 plant species taxa occurred in the rice-fish mixed paddy fields with a fish habitat and did not occur in the conventional paddy field lacking fish habitat. This difference is thought to arise from differences in moisture requirements for vegetation. Life form analysis demonstrated differences in hemicryptophytes, therophytes, and hydrophytes according to fish habitat. The naturalized plants identified were also determined to be species widely distributed throughout Korea. Frequency analysis demonstrated that the rice-fish mixed paddy fields with a fish habitat had a high ratio of both obligate and facultative wetland plants relative to the conventional paddy field. Based on the study results, it is likely that vegetation-diversity will increase with environment diversity. However, no statistical significance was observed according to paddy types. Future research should aim to identify additional environmental factors, including the existence of fish habitat, habitat area, depth of fish habitat, hydrological parameters, water quality, and paddy soil environment, to enhance vegetation-diversity and biocultural diversity.

• Korean Journal of Environment and Ecology
• /
• v.33 no.3
• /
• pp.266-279
• /
• 2019

We investigated the characteristics of fish communities and habitat status of endangered species Rhodeus pseudosericeus in Heuk Stream, a tributary of the Han River, from April to October 2018. During this period, we collected 47 species of 14 families from 10 survey stations using kick nets, cast nets, and long bag set nets. The dominant and subdominant species were Zacco platypus (37.6%) and Z. koreanus (13.8%), respectively. The next most abundant species were Squalidus gracilis majimae (11.1%), Pungtungia herzi (7.7%), Rhodeus pseudosericeus (5.0%), Microphysogobio yaluensis (4.3%), and Hemibarbus longirostris (3.0%). Among the fish collected, 19 species (40.4%) were Korean endemic species. Endangered species were R. pseudosericeus and Acheilognathus signifer while exotic species were Micropterus salmoides and Oncorhynchus mykiss, and land-locked species were Plecoglossus altivelis and Rhinogobius brunneus. The community analysis showed that the dominance and evenness indexes were mostly low and that the diversity and richness indexes were high. Moreover, the river health (index of biological integrity) was mostly excllent (1 site is good, 9 sites are very good). R. pseudosericeus inhabited widely from St. 3 to St. 9 in Heuk Stream, and its population size was large. Age groups for R. pseudosericeus estimated by the frequency distribution of total length in spawning season (April) indicated the 32~45 mm group as 1-year old, the 46~59 mm group as 2-years old, 60~69 mm group as 3-years old, and the 70~89 mm group as 4-years or older. Total length range of male and female was similar, and the sex ratio of female (426) to male (394) was 1 : 0.95. A. signifer, which had been released in Heuk Stream, inhabited from St. 4 to St. 5, but its population size was small. Lastly, this paper discusses a conservation plan for fish in Heuk Stream.

• Journal of Nutrition and Health
• /
• v.52 no.5
• /
• pp.449-464
• /
• 2019

Purpose: North Koreans could be at higher risk for their bone health because of previous periods of severe famine and the continuing low availability of food. This study determined the bone mineral density (BMD) status and its relationship with dietary behaviors and nutrient intake of North Korean refugees (NKR) in South Korea (SK). Methods: This cross-sectional study analyzed 110 female NKR from a NORNS cohort of a non-probability sample of adult NKR in Seoul. BMD examined by DEXA was used to divide participants into the normal group (NG) and the non-normal group (NNG) according to the WHO guideline. A self-administered questionnaire included questions on age, the socioeconomic situation in North Korea (NK) and SK, the food security in NK and SK, and the health behaviors, dietary behaviors, and food frequency questionnaire administered in SK. A one-day 24-hr recall was conducted and the results were analyzed by using CanPro. SPSS was used to analyze whether BMD and related dietary behaviors and nutrient intakes differed according to the groups. Results: NG (62.7%) was significantly younger and had a lower abdominal obesity score than NNG (p < 0.001). While 14.5% of NG reported experiencing menopause, all of NNG reported experiencing menopause. The NG more frequently consumed the dairy group of foods (9.6 times a week) than did the NNG (4.8 times a week) after the statistics were adjusted for age (p < 0.007). The NG consumed significantly more animal protein and animal calcium than did the NNG (p = 0.01, p = 0.009, respectively). Calcium intake was low with 49.3% of NG, and 78.0% of the NNG reported consuming calcium lower than the estimated average requirement. Only calcium showed an index of nutrient quality lower than one in both groups. Conclusion: These results showed that NKR women and possibly all North Korean women are at high risk for bone health and they consumed low levels of bone-related nutrients, and this should be considered for the nutrition policy for NKR and North Korea.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.21 no.1
• /
• pp.55-64
• /
• 2019

The flowering seasons can be advanced due to climate change that would cause an abnormally warm winter. Such warm winter would increase the frequency of crop damages resulted from sudden occurrences of low temperature before and after the vegetative growth stages, e.g., the period from germination to flowering. The degree and pattern of freezing damage would differ by the development stage of each individual fruit tree even in an orchard. A critical temperature, e.g., killing temperature, has been used to predict freeze damage by low-temperature conditions under the assumption that such damage would be associated with the development stage of a fruit flower bud. However, it would be challenging to apply the critical temperature to a region where spatial variation in temperature would be considerably high. In the present study, a phenological model was used to estimate major bud development stages, which would be useful for prediction of regional risks for the freeze damages. We also derived a linear function to calculate a probabilistic freeze risk in spring, which can quantitatively evaluate the risk level based solely on forecasted weather data. We calculated the dates of freeze damage occurrences and spatial risk distribution according to main production areas by applying the spring freeze risk function to apple, peach, and pear crops in 2018. It was predicted that the most extensive low-temperature associated freeze damage could have occurred on April 8. It was also found that the risk function was useful to identify the main production areas where the greatest damage to a given crop could occur. These results suggest that the freezing damage associated with the occurrence of low-temperature events could decrease providing early warning for growers to respond abnormal weather conditions for their farm.

• Journal of Environmental Impact Assessment
• /
• v.30 no.5
• /
• pp.271-296
• /
• 2021

Since the thermal stratification in a reservoir inhibits the vertical mixing of the upper and lower layers and causes the formation of a hypoxia layer and the enhancement of nutrients release from the sediment, changes in the stratification structure of the reservoir according to future climate change are very important in terms of water quality and aquatic ecology management. This study was aimed to develop a data-driven inflow water temperature prediction model for Daecheong Reservoir (DR), and to predict future inflow water temperature and the stratification structure of DR considering future climate scenarios of Representative Concentration Pathways (RCP). The random forest (RF)regression model (NSE 0.97, RMSE 1.86℃, MAPE 9.45%) developed to predict the inflow temperature of DR adequately reproduced the statistics and variability of the observed water temperature. Future meteorological data for each RCP scenario predicted by the regional climate model (HadGEM3-RA) was input into RF model to predict the inflow water temperature, and a three-dimensional hydrodynamic model (AEM3D) was used to predict the change in the future (2018~2037, 2038~2057, 2058~2077, 2078~2097) stratification structure of DR due to climate change. As a result, the rates of increase in air temperature and inflow water temperature was 0.14~0.48℃/10year and 0.21~0.41℃/10year,respectively. As a result of seasonal analysis, in all scenarios except spring and winter in the RCP 2.6, the increase in inflow water temperature was statistically significant, and the increase rate was higher as the carbon reduction effort was weaker. The increase rate of the surface water temperature of the reservoir was in the range of 0.04~0.38℃/10year, and the stratification period was gradually increased in all scenarios. In particular, when the RCP 8.5 scenario is applied, the number of stratification days is expected to increase by about 24 days. These results were consistent with the results of previous studies that climate change strengthens the stratification intensity of lakes and reservoirs and prolonged the stratification period, and suggested that prolonged water temperature stratification could cause changes in the aquatic ecosystem, such as spatial expansion of the low-oxygen layer, an increase in sediment nutrient release, and changed in the dominant species of algae in the water body.

• Journal of Nutrition and Health
• /
• v.53 no.6
• /
• pp.596-612
• /
• 2020

Purpose: This study was conducted to evaluate the dietary behaviors of preschool children using the nutrition quotient for preschoolers (NQ-P) and investigate factors that influence NQ-P in preschool children. Methods: Subjects were 214 parents with children aged 3-5 years residing in Busan and Gyeongnam, Korea. The survey was conducted from March to April, 2019 using a questionnaire that included demographic characteristics, the NQ-P questions, and health consciousness. All data was statistically analyzed by the SPSS program (Ver 25.0) and the statistical differences in variables were evaluated by the chi-square test, Fisher's exact test, t-test, one-way ANOVA, and Tukey's multiple comparison test. Results: The mean score of NQ-P of the total subjects was 58.28, which was within the medium-low grade. The mean score of 'balance' was 60.08, 'moderation' was 47.64, and 'environment' was 67.83. The analysis of related-factors influencing NQ-P scores showed that there was a significant difference according to the frequency of dining out. The scores of the NQ-P (p < 0.05), moderation (p < 0.001), and environment (p < 0.05) were significantly higher in the 1-2 times per week group compare to 3-4 times and 5-6 times per week group. The scores of NQ-P (p < 0.01), environment (p < 0.01) were significantly higher in the high group of parents' health consciousness compared to the those with low health consciousness. Conclusion: According to the results of the evaluation by NQ-P, the dietary behaviors of preschool children residing in Busan and Gyeongnam need to be improved and monitored. For improving their eating behavior and nutritional health status, preschool children and their parents need proper nutrition education programs.