• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.363-370
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• 2018

The succulent plants of Echeveria genus are in increasing demand worldwide, but it is difficult to supply good quality young plants throughout the year because propagation efficiencies are depend on cultivar and environmental factors. This study was carried out to investigate the propagation efficiencies of leaf cutting in Echeveria cultivars at different LED light qualities in a closed-type plant factory system. Leaf cuttings cut from stock plants of six difficult-to-propagated cultivars 'Afterglow (AG)', 'Berkeley Light (BL)', 'Mason (MS)', 'Subsessilis Light (SL)', 'Cream Tea (CT)', and 'Ben Badis (BB)' were put into cutting media in the plant factory system maintained at a temperature of $24{\pm}2^{\circ}C$ and relative humidity of $60{\pm}10%$, and watered with over-head irrigation twice a week. Cuttings were irradiated with sole or mixed red (R, 660 nm), blue (B, 450 nm), green (G, 530 nm), and far-red (FR, 730 nm) LEDs as follows: R10, R8+B2, R5+B5, R7+B2+FR1, and R7+B2+G1. PPFD just above the cuttings was $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and photoperiod was 16/8 (light/dark) hours. As a result, propagation efficiencies were dependent on cultivar. Rooting and shooting were relatively easy in 'SL' but shoot formation in 'AG' was very difficult. Light qualities from LEDs also affected plant regeneration. Light conditions with a higher ratio of B, R5+B5, R7+B2+FR1, and R7+B2+G1, promoted shoot formation and growth but inhibited rooting and root growth. R10 and R8+B2 with a higher ratio of R promoted rooting and root growth and inhibited shoot formation and growth of cuttings. In addition, the treatment with FR increased leaf size and biomass of the all plants. Therefore, further studies are needed to investigate the optimum compositions of LED light quality for the improvement of leaf cutting efficiency in difficultto-propagated Echeveria cultivars.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.431-438
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• 2012

The developmental time of the nymphs of Myzus persicae was studied in the laboratory (six constant temperatures from 15 to $30^{\circ}C$ with 50~60% RH, and a photoperiod of 14L:10D) and in a green-pepper plastic house. Mortality of M. persicae in laboratory was high in the first(6.7~13.3%) and second instar nymphs(6.7%) at low temperatures and high in the third (17.8%) and fourth instar nymphs(17.8%) at high temperatures. Mortality was 66.7% at $33^{\circ}C$ in laboratory and $26.7^{\circ}C$ in plastic house. The total developmental time was the longest at $14.6^{\circ}C$ (14.4 days) and shortest at $26.7^{\circ}C$ (6.0 days) in plastic house. The lower threshold temperature of the total nymphal stage was $3.0^{\circ}C$ in laboratory. The thermal constant required for nymphal stage was 111.1DD. The relationship between developmental rate and temperature was fitted nonlinear model by Logan-6 which has the lowest value on Akaike information criterion (AIC) and Bayesian information criterion (BIC). The distribution of completion of each developmental stage was well described by the 3-parameter Weibull function ($r^2=0.95{\sim}0.97$). This model accurately described the predicted and observed occurrences. Thus the model is considered to be good for use in predicting the optimal spray time for Myzus persicae.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.421-429
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• 2012

The developmental time period of Aphis gossypii was studied in laboratory (six constant temperatures from 15 to $30^{\circ}C$ with 50~60% RH, and a photoperiod of 14L:10D) and in a cucumber plastic house. The mortality of A. gossypii in the laboratory was high in the 2nd (20.0%) and 3rd stage(13.3%) at low temperature but high in the 3rd (26.7%) and 4th stage (33.3%) at high temperatures. Mortality in the plastic house was high in the 1st and 2nd stage but there was no mortality in the 4th stage at low temperature. The total developmental period was longest at $15^{\circ}C$ (12.2 days) in the laboratory and shortest at $28.5^{\circ}C$ (4.09 days) in the plastic house. The lower threshold temperature at the total nymphal stage was $6.8^{\circ}C$ in laboratory. The thermal constant required to reach the total nymphal stage was 111.1DD. The relationship between the developmental rate and temperature fit the nonlinear model of Logan-6 which has the lowest value for the Akaike information criterion(AIC) and Bayesian information criterion(BIC). The distribution of completion of each development stage was well described by the 3-parameter Weibull function ($r^2=0.89{\sim}0.96$). This model accurately described the predicted and observed outcomes. Thus it is considered that the model can be used for predicting the optimal spray time for Aphis gossypii.

• Journal of agricultural medicine and community health
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• v.36 no.2
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• pp.87-100
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• 2011

Objectives: This study aimed to identify factors associated with smoking relapse. Methods: The study sample was recruited among subjects who were enrolled in the smoking cessation clinic of a public health center and had succeeded in quitting smoking for at least six months. A total of 159 male subjects were followed via mail survey one year later. The independent variables in the analyses were socio-demographic characteristics, smoking history and behavior, receipt of smoking cessation aids, health behaviors and components of the health belief model (HBM). The dependent variable was smoking relapse assessed one year after quitting. Ordered logit regressions were used to identify factors associated with smoking relapse. Results: The relapse rate of the ex-smokers in our sample was 25.8%, and the occasional smoking rate was 17.0%. Univariate analyses revealed that only factors related to the HBM, such as perceived susceptibility to diseases (p<0.01), perceived severity of diseases (p<0.01), perceived health benefits of not smoking (p<0.01), perceived barriers to quitting smoking due to increasing stress and difficulty in social life (p<0.01), and self-efficacy (p<0.01) were associated with the likelihood of relapse for ex-smokers. Ordered logit analyses yielded two significant factors affecting the likelihood of relapse, the perceived barriers to quitting smoking and self-efficacy. Conclusions: Our results indicate that higher levels of barriers to quitting smoking and lower levels of self-efficacy were significantly related to risk of smoking relapse. These findings may be useful for identifying those at highest risk for relapse and choosing the optimal strategies for prevention of relapse for ex-smokers.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.4
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• pp.158-166
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• 2008

The pumpkin fruit fly, Bactrocera depressa (Tephritidae: Diptera), is one of the most important pests in Cucurbitaceae plants. This study was conducted to investigate the basic ecology of B. depressa, and to develop a forecasting model for predicting the time of adult emergence in early season. In green pumpkin producing farms, the oviposition punctures caused by the oviposition of B. depressa occurred first between mid- and late July, peaked in late August, and then decreased in mid-September followed by disappearance of the symptoms in late September, during which oviposition activity of B. depressa is considered active. In full-ripened pumpkin producing farms, damaged fruits abruptly increased from early Auguest, because the decay of pumpkins caused by larval development began from that time. B. depressa produced a mean oviposition puncture of 2.2 per fruit and total 28.8-29.8 eggs per fruit. Adult emergence from overwintering pupae, which was monitored using a ground emergence trap, was first observed between mid- and late May, and peaked during late May to early June. The development times from overwintering pupae to adult emergence decreased with increasing temperature: 59.0 days at $15^{\circ}C$, 39.3 days at $20^{\circ}C$, 25.8 days at$25^{\circ}C$ and 21.4 days at $30^{\circ}C$. The pupae did not develop to adult at $35^{\circ}C$. The lower developmental threshold temperature was calculated as $6.8^{\circ}C$ by linear regression. The thermal constant was 482.3 degree-days. The non-linear model of Gaussian equation well explained the relationship between the development rate and temperature. The Weibull function provided a good fit for the distribution of development times of overwintering pupae. The predicted date of 50% adult emergence by a degree-day model showed one day deviation from the observed actual date. Also, the output estimated by rate summation model, which was consisted of the developmental model and the Weibull function, well pursued the actual pattern of cumulative frequency curve of B. depressa adult emergence. Consequently, it is expected that the present results could be used to establish the management strategy of B. depressa.

• Journal of Marine Life Science
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• v.5 no.1
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• pp.9-16
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• 2020

We evaluated the toxic effects of antifouling paint (irgarol and diuron) on the population growth rate (r) of the marine diatom, Skeletonema costatum. The r of S. costatum was determined after 96 hrs of exposure to irgarol (0, 0.31, 0.63, 1.25, 2.5 and 5 ㎍ l^-1) and diuron (0, 7.81, 15.63, 31.25, 62.5 and 125 ㎍ l^-1). It was observed that r in the control (absence of irgarol and diuron) were greater than 0.04, while r in the treatment groups decreased with increasing irgarol and diuron concentrations. Irgarol and diuron reduced r in a dose-dependent manner with significant decreases occurring at concentrations above 0.63 and 15.63 ㎍ l^-1, respectively. The EC₅₀ values of r in irgarol and diuron exposure were 1.09 and 45.45 ㎍ l^-1. No observed effect concentration (NOEC) were 0.31 and 7.81 ㎍ l^-1, the lowest observed effect concentration (LOEC) were 0.63 and 15.63 ㎍ l^-1. This result indicate that a concentration of greater than 0.63 ㎍ l^-1 of irgarol and 15.63 ㎍ l^-1 of diuron in marine ecosystems induced to decreasing r of S. costatum. Also, these toxic values can be useful as a baseline data for the toxic evaluation of irgarol and diuron in marine ecosystems.

• 한국사회정책
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• v.25 no.2
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• pp.125-163
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• 2018

Social and health problems related to drinking are serious. Drinking behavior is affected not only by personal factors but also by environment factors. The purpose of this study is to find out how the alcoholic beverage stores in community influence the drinking behaviors of individuals after adjusting the individual level variables and provide it as basic data for alcohol related regulatory policies. In order to identify the factors affecting drinking behavior, we conducted a multilevel logistic regression analysis with high-risk drinking and current drinking as dependent variables. Individual-level data provided by 2015 community health survey from respondents of urban residents, and regional level data provided by the National Statistical office. The variables such as age, education level, and income level were used as individual level variables and the number of basic living allowances, divorce rate, and the number of pubs were used as community level variables. According to the research results, after controlling all variables, the number of bar, retail per $1km^2$ in residential area effect on current drinking. But, they are not effect on high risk drinking. In the high risk drinking, only the divorce rate effect on drinking behavior. As a result of the stratified analysis, there was no difference in the current drinking. But, it shows that the higher the number of retail stores and the total alcohol availability, the higher risk drinking behavior in the 60s. The results of this study suggest that policies aimed not only on individuals but also on the local environment are necessary.

• Journal of Marine Life Science
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• v.2 no.1
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• pp.20-26
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• 2017

In this study, we evaluated the toxic effects of heavy metals (As, Cr and Pb) on the population growth rate (r) of the marine diatom, Skeletonema costatum. The r of the species was determined after 96 h (4 days) exposure to As (0, 0.31, 0.63, 1.25, 2.50 and 5.00 mg L^-1), Cr (0, 0.16, 0.31, 0.63, 1.25 and 2.50 mg L^-1) and Pb (0, 1.25, 2.50, 5.00, 10.00 and 20.00 mg L^-1). It was observed that r in the control (absence of As, Cr and Pb) were greater than 0.04, however suddenly decreased with increased heavy metal concentrations. As, Cr and Pb reduced r in a dose-dependent manner and a significant reduction were occurred at concentration of greater than 0.31, 0.31 and 5.00 mg L^-1, respectively. Based on the toxicity, the heavy metal were ranked as Cr>As>Pb, with EC₅₀ (50% effective concentration) values of 0.80, 2.57 and 13.88 mg L^-1, respectively. The lowest-observed-effective-concentration (LOEC) of r in exposed to As, Cr and Pb were 0.63, 0.63 and 10.00 mg L^-1, respectively. Precisely, a concentration of greater than 0.63 mg L^-1 of As, 0.63 mg L^-1 of Cr and 10.00 mg L^-1 of Pb in marine ecosystems induced toxic effect on the r of S. costatum. Based on our results, we suggested that the r of S. costatum might be a useful bio-indicator for the toxicity assessment of heavy metals on the producer in marine ecosystems.

• Korean Journal of Plant Resources
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• v.37 no.2
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• pp.149-160
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• 2024

In Korea, potatoes have served as a side dish, but their role as snacks, such as chips or French fries, has recently gained traction. While there is a high demand for processing potatoes, there remains a dearth of research on the impact of double cropping, particularly during autumn, on processing quality. Therefore, this study was conducted to determine the effects of different spring potato cultivation periods on growth, yield, and processing quality during autumn cultivation. Following spring planting, harvest was carried out four times: 70 days, 80 days, 90 days, and 100 days. Subsequently, autumn cultivation was carried out in Gangneung and Seocheon regions using these seed potatoes. Results showed an increase in above-ground emergence rate with shorter spring growing period. When seed potatoes with a spring cultivation period of 80 and 90 days were grown in the autumn in the Gangneung region, the stem length was 47.2 to 48.9, which was greater than that of other treatments. However, stem number and leaf color (SPAD) showed no significant differences across cultivation periods. The number of tubers, tuber weight, yield, and marketable yield did not vary significantly with cultivation periods but described clear cultivar dependent differences. The tuber weight of the Saebong cultivar in Gangneung and the Eunseon cultivar in Seocheon was superior. The starch content peaked at 7.9% when seed potatoes grown for 80 days in the spring were harvested after autumn cultivation in the Gangneung region, but there was no significant differences in the Seocheon region. Glucose content showed a clear difference depending on the cultivation period, increasing with longer spring cultivation period during autumn cultivation. In conclusion, as a result of the effect of the spring potato cultivation period on the growth, yield, and processing quality of tubers when cultivating potatoes in double-cropping, the differences depending on the cultivation period were insignificant, while cultivar-based disparities were pronounced. The Eunseon cultivar exhibited robust above-ground growth and yield, while the Saebong cultivar demonstrated excellent processing quality.

• Food Science and Preservation
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• v.30 no.6
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• pp.1095-1106
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• 2023

This study investigated the anti-oxidative and anti-inflammatory effects of Aster glehni (AG) extract in RAW 264.7 cells and Caenorhabditis elegans. The total polyphenol and flavonoid contents were higher in the ethanol extracts than in the hot water extracts. As a result of measuring the moisture contents (%) and extraction yields (%) of AG and drying A. glehni for processing (DAG), 70% ethanol, which has the highest percentage of extraction yield, was selected as the final solvent. DPPH radical scavenging activity showed higher antioxidant activity of ethanol extracts of DAG than AG. The cytotoxicity assay of the AG or DAG ethanol extracts was treated at different concentrations (25, 50, and 100 ㎍/mL), and cell viability rates were higher than 80% at all concentrations. The LPS-stimulated nitric oxide (NO) production in RAW 264.7 was significantly reduced at all concentrations of AG and DAG groups. As a result of measuring the gene expression of iNOS, which induces NO production, the AG or DAG group decreased by 33% and 32%, compared with the phosphate buffer saline (PBS) group. Under inflammatory stress conditions, the survival rate of C. elegans treated with AG or DAG ethanol extract with LPS showed concentration-dependent improvement in survival rate compared with the PBS group. Considering these results, AG could potentially be developed as an antioxidant and anti-inflammatory functional food material.