• Journal of Astronomy and Space Sciences
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• v.30 no.4
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• pp.241-246
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• 2013

We have investigated drought periodicities occurred in Seoul to find out any indication of relationship between drought in Korea and solar activities. It is motivated, in view of solar-terrestrial connection, to search for an example of extreme weather condition controlled by solar activity. The periodicity of drought in Seoul has been re-examined using the wavelet transform technique as the consensus is not achieved yet. The reason we have chosen Seoul is because daily precipitation was recorded for longer than 200 years, which meets our requirement that analyses of drought frequency demand long-term historical data to ensure reliable estimates. We have examined three types of time series of the Effective Drought Index (EDI). We have directly analyzed EDI time series in the first place. And we have constructed and analyzed time series of histogram in which the number of days whose EDI is less than -1.5 for a given month of the year is given as a function of time, and one in which the number of occasions where EDI values of three consecutive days are all less than -1.5 is given as a function of time. All the time series data sets we analyzed are periodic. Apart from the annual cycle due to seasonal variations, periodicities shorter than the 11 year sunspot cycle, ~ 3, ~ 4, ~ 6 years, have been confirmed. Periodicities to which theses short periodicities (shorter than Hale period) may be corresponding are not yet known. Longer periodicities possibly related to Gleissberg cycles, ~ 55, ~ 120 years, can be also seen. However, periodicity comparable to the 11 year solar cycle seems absent in both EDI and the constructed data sets.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.203-203
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• 2016

The linkage between climate change and water security, i.e., the response of water resource to the future climate change, have been of great concern to both scientific community and policy makers. In this study, the impact of future climate on water resources in Yellow River Basin in North of China has been investigated using the Coupled Land surface and Hydrology Model System (CLHMS) and IPCC AR5 projected future climate change in the basin. Firstly, the performances of 14 IPCC AR5 models in reproducing the observed precipitation and temperature in China, especially in North of China, have been evaluated, and it's suggested most climate models do show systematic bias compared with the observation, however, CNRM-CM5、HadCM5 and IPSL-CM5 model are generally the best models among those 14 models. Taking the daily projection results from the CNRM-CM5, along with the bias-correction technique, the response of water resources in Yellow river basin to the future climate change in different emission scenarios have been investigated. All the simulation results indicate a reduction in water resources. The current situation of water shortage since 1980s will keep continue, the water resources reduction varies between 28 and 23% for RCP 2.6 and 4.5 scenarios. RCP 8.5 scenario simulation shows a decrease of water resources in the early and mid 21th century, but after 2080, with the increase of rainfall, the extreme flood events tends to increase.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.53.1-53.15
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• 2023

Background: Plastics are high-molecular-weight materials composed of long carbon chains. They are prevalent in daily life, present in various items such as food containers and microwavable packaging. Phthalates, an additive used to enhance their flexibility, are endocrine-disrupting chemicals. We utilized the data from the Korean National Environmental Health Survey (KoNEHS) cycle 3, representing the general South Korean population, to investigate the relationship between the use of plastics in refrigerator food storage and phthalate exposure. Methods: We assessed 3,333 adult participants (aged ≥ 19 years) including 1,526 men and 1,807 women, using data from KoNEHS cycle 3. Using the 75th percentile concentration, urine phthalate metabolites were categorized into high and low-concentration groups. χ² test was conducted to analyze variations in the distribution of each variable, considering sociodemographic factors, health-related factors, food intake, the use of plastics, and the concentration of urine phthalate metabolites as the variables. To calculate odds ratios (ORs) for the high-concentration group of urine phthalate metabolites based on the use of plastics in refrigerator food storage, logistic regression analysis was conducted. Results: In men, the use of plastics in refrigerator food storage had significantly higher adjusted ORs compared to those using the others. The adjusted ORs were calculated as follows: mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) had an OR of 1.35 (95% confidence interval [CI]: 1.05-1.72), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) had an OR of 1.48 (95% CI: 1.16-1.88), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP) had an OR of 1.32 (95% CI: 1.04-1.66), ∑di(2-ethylhexyl) phthalate (∑DEHP) had an OR of 1.37 (95% CI: 1.08-1.74) and mono-n-butyl phthalate (MnBP) had an OR of 1.44 (95% CI: 1.13-1.84). Conclusion: The concentrations of urine phthalate metabolites (MEHHP, MEOHP, MECPP, ∑DEHP, and MnBP) were significantly higher in men who used plastics in refrigerator food storage compared to those using the others.

• Tuberculosis and Respiratory Diseases
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• v.63 no.2
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• pp.154-164
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• 2007

Background: Irinotecan hydrochloride, a topoisomerase I inhibitor, is effective against small-cell lung cancer. Irinotecan also can act as a potential radiation sensitizer along with cisplatin. To evaluate efficacy and toxicity of irinotecan plus cisplatin (IP) with concurrent thoracic radiotherapy, we conducted a phase II study of IP followed by concurrent IP plus hyperfractionated thoracic radiotherapy in patients with previously untreated limited-stage small-cell lung cancer. Methods: Twenty-four patients with previously untreated small-cell lung cancer were enrolled onto the study since November 2004. Irinotecan $60mg/m^2$ was administered intravenously on days 1 and 8 in combination with cisplatin $60mg/m^2$ on day1 every 21 days. From the first day of third cycle, twice-daily thoracic irradiation (total 45 Gy) was given. Prophylactic cranial irradiation was given to the patients who showed complete remission after concurrent chemoradiotherapy. Restaging was done after second and sixth cycle with chest CT and/or bronchosocpy. Results: Up to November 2004, 19 patients were assessable. The median follow-up time was 12.5 months. A total of 99 cycles (median 5.2 cycles per patient) were administered. The actual dose intensity values were cisplatin $19.6mg/m^2$/week and irinotecan $38.2mg/m^2$/week. Among the 19 patients, the objective response rate was 95% (19 patients), with 9 patients (47%) having a complete response (CR). The major grade 3/4 hematological toxicities were neutropenia (35% of cycles), anemia (7% of cycles), thrombocytopenia (7% of cycles). Febrile neutropenia was 4% of cycles. The predominant grade 3/4 non-hematological toxicities was diarrhea (5% of cycles). Toxicities was not significantly different with concurrent administration of irinotecan and cisplatin with radiotherapy, except grade 3/4 radiation esophagitis (10% of patients). No treatment-related deaths were observed. The 1-year and 2-year survival rate of eligible patients was 89% (16/18) and 47% (9/18), respectively. Conclusion: Three-week schedule of irinotecan plus cisplatin followed by concurrent IP plus hyperfractionated thoracic radiotherapy is an effective treatment for limited disease small-cell lung cancer, with acceptable toxicity.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.6-10
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• 2003

The present study investigated peripheral plasma immunoreactive inhibin (ir-inhibin) concentrations in relation to the stage of oestrous cycle and progesterone concentrations in cycling Sahiwal cattle (Bos indicus) and Murrah buffaloes (Bubalus bubalis). Blood samples were collected once daily for thirty-two consecutive days from cattle and buffaloes (5 each) during winter months of January and February. Mean (${\pm}$S.E.M.) plasma ir-inhibin concentrations ranged from $0.40{\pm}0.01$ to $0.59{\pm}0.03ng/ml$ in cattle and from $0.29{\pm}0.03$ to $0.52{\pm}0.05ng/ml$ in buffaloes. In cattle, ir-inhibin concentrations increased from $0.47{\pm}0.07ng/ml$ on day -4 (day 0=day of oestrus) to reach a maximum value of $0.59{\pm}0.03ng/ml$ on day -2. Thereafter, ir-inhibin concentrations showed a decline to reach a low of $0.40{\pm}0.01ng/ml$ on day 11 of the oestrous cycle. In buffaloes, ir-inhibin concentrations increased from $0.38{\pm}0.04 ng/ml$ on day -4 to reach a maximum concentration of $0.52{\pm}0.05ng/ml$ on day -2. Ir-inhibin concentrations then declined to reach a low of $0.29{\pm}0.03ng/ml on day 9 of the cycle. In both cattle and buffaloes, ir-inhibin concentrations which were lowest ($0.43{\pm}0.02$ and $0.34{\pm}0.02ng/ml$, respectively) during the mid-luteal phase of the oestrous cycle increased (p<0.05) to $0.52{\pm}0.03$ and $0.44{\pm}0.04ng/ml$, respectively, during the late luteal phase, and then further to the highest value of $0.53{\pm}0.02$ and $0.49{\pm}0.04ng/ml$, respectively, during the perioestrus phase, following which these declined to $0.50{\pm}0.02$ and $0.39{\pm}0.03ng/ml$, respectively, during the early luteal phase. The variations in peripheral plasma ir-inhibin profile in both the species appear to be related to the changes in characteristics of follicular populations during the oestrous cycle. Peripheral plasma ir-inhibin concentrations were negatively correlated with progesterone concentrations in cattle (r=-0.51, p<0.01) and buffaloes (r=-0.30, p<0.01) indicating that the corpus luteum is not a source of peripheral ir-inhibin in these species.

• Korean Journal of Veterinary Research
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• v.35 no.4
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• pp.833-841
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• 1995

Ultrasonography was used to measure the corpus luteum area for determining the relationships between corpus luteum size and milk progesterone concentration during the estrous cycle in 16 dairy cows. Cows were classified retrospectively into cows that had corpus luteum with(n=P) and without(n=7) cavity. Ultrasound examination and collection of milk samples for progesterone assay were performed with 2 day intervals from Days 0 to 12, and then daily from Day 14 to the day of the next ovulation. The means for corpus luteum area and for milk progesterone concentration during the estrous cycle were not significantly different between cows that had corpus luteum with and without cavity. The correlation coefficients between corpus luteum area and milk progesterone concentration during luteal development (Days 2 to 8) were 0.71(p<0.0001) and 0.74(p<0.0001) for corpus luteum with and without cavity, respectively, during luteal regression(Days -6 to 0 relative to the next ovulation) 0.73(p<0.0001) and 0.76(p<0.0001), respectively. The correlation coefficients combined fur both stages of estrous cycle and both luteal statuses were 0.70(p<0.0001). These results indicate that corpus luteum area is significantly correlated to milk progesterone concentration, and ultrasonographic assessment of the corpus luteum is a reliable method fur estimating peripheral progesterone concentrations during the estrous cycle in cows.

• Korean Journal of Veterinary Research
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• v.34 no.4
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• pp.881-890
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• 1994

Skim milk progesterone($P_4$) profiles in 74 dairy cows were determind to monitor postpartum ovarian activity by radioimmunoassay. Milk samples were collected from each cow every 5 days from 10 to 90 days postpartum. Signs of estrus were observed twice daily, and status of the ovaries and uterus were examined every 10 days by rectal palpation. Results are summarized as follows: 1. Cows were categorized into five types by the change of skim milk $P_4$ profiles; Type I(normal) : Cyclic changes of skim milk $P_4$ profiles appeared within 20 days postpartum(12 cows, 16.2%), Type II(cycle delayed) : Cyclic changes of skim milk $P_4$ profiles appeared from 21 to 60 days postpartum(39 cows, 52.7%), Type III(cycle ceased with low $P_4$) : Onset of the estrous cycle within 20 days postpartum but ceased later with low levels of $P_4$ (7cows, 9.5%), Type IV(cycle ceased with high $P_4$) : Onset of the estrous cycle within 20 days postpartum but ceased later with high levels(>3.0 ng/ml) of skim milk $P_4$ (4 cows, 5.4%), Type V(acyclicity) : Skim milk $P_4$ concentration remained low(<1.0 ng/ml) until 80 days postpartum(12 cows, 16.2%). 2. Out of the 17 cows classified as the Type III and Type V by skim milk $P_4$ profiles, 13 cows had inactive ovaries and remaining 6 cows had single or multiple follicular cysts in their ovaries by rectal palpation. All 4 cows of Type IV had a persistent corpus luteum in their ovaries. 3. Approximately eighty percent of the cows had begun ovarian activity by 60 days postpartum and 90.6% by 90 days by skim milk $P_4$ profiles, but only 39.2% by 60 days and 71.7% by 90 days had shown visible estrus signs. The mean days from parturition to the first, second and third ovulations determined by skim milk $P_4$ profiles was $28.0{\pm}11.0$, $46.4{\pm}13.3$ and $66.4{\pm}11.5$ days and the visible estrus signs were 9.3%, 38.1%, and 48.6%, respectively. The mean days from parturition to the first visible estrus was $57.2{\pm}15.9$ days. These results indicated that milk $P_4$ profile of each Types by radioimmunoassay can be utilized for monitoring postpartum ovarian and would be useful for the early detection of ovarian dysfunction in dairy cow.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.2
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• pp.188-196
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• 2010

The objective of this study was to characterize the litter sizes in Huanghuai goats with high prolificacy (HP, five or more kids born per litter on at least one occasion), and to compare their peripheral blood concentrations of progesterone and estradiol with those of goats with poor prolificacy (PP, up to three kids born per litter on any occasion). The circulating concentrations of progesterone and estradiol were measured by radioimmunoassay from daily blood samples taken during natural estrus cycles and at 1-5 days after ovariectomy. Estrus was synchronized using two doses of a prostaglandin analog. Litter size for the HP goats increased up to a parity of five and decreased thereafter. The percentage of goats with litter sizes of $\geq$4 from parities 3 to 6 ranged from 44.5% to 58.3%. Although small differences in litter size were obtained for goats of parities three, four and six relative to five, parity five does had the highest mean litter size. Progesterone concentrations began to rise earlier and were higher in the HP than in the PP goats on most days of the luteal phase, but not during the follicular phase of the cycle or after ovariectomy. There was a significant difference between the two groups (p<0.05) in the magnitude of the progesterone plateau. Mean estradiol concentrations in the HP group remained significantly higher than in the PP group (p<0.05) during the estrus cycle. There were two estradiol peaks in the HP goats during the early luteal phase, but only one in the PP group. Measurements of individual corpora lutea (CL) in vitro showed that there was a greater prevalence of small CL (<6 mm in diameter) in the HP group than in the PP group (p<0.05). After ovariectomy, the estradiol level on day 1 was significantly higher than at the nadir during the estrus cycle in both the HP (p<0.01) and PP (p<0.05) goats, while levels decreased by 12.3% and 26.2% respectively compared with the mid-luteal period in HP and PP goats (p<0.05). The overall mean estradiol concentrations in HP goats were lower than in the PP group, but no significant differences were found between groups at 1-5 days after ovariectomy.

• Korean Journal of Ecology and Environment
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• v.37 no.2 s.107
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• pp.205-212
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• 2004

Phosphorus cycle was studied in a deep stratified reservoir in summer monsoon area (Lake Soyang, Korea) by surveying phosphorus input from the watershed and the movement of phosphorus within the reservoir. And the spatial and temporal distribution of phosphorus was modeled with a 2-dimensional water quality model (CE-QUAL-W2), Phosphorus loading was calculated by measuring TP in the main inflowing river (the Soyang River) accounting for 90% of watershed discharge. TP of the Soyang River showed a large daily variation with the flow rate. High phosphorus loading occurred during a few episodic storm runoff laden with suspended sediments and phosphorus. Because storm runoff water on rainy days have lower temperature, it plunges into a depth of same temperature (usually below 20m depth), forming an intermediate turbidity layer with a thickness of 20 ${\sim}$ 30 m. Because of stable thermal stratification in summer the intermediate layer water of high phosphorus content was discharged from the dam through a mid-depth outlet without diffusing into epilimnion. The movement of runoff water within the reservoir, and the subsequent distribution of phosphorus were well simulated by the water quality model showing a good accuracy. The major parameter for the calibration of phosphorus cycle was a settling velocity of detritus, which was calibrated to be 0.75 m ${\cdot}$ $day^{-1}$. It is concluded that the model can be a good simulator of limnological phenomena in reservoirs of summer monsoon area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.977-988
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• 2006

The goal of this study is to develop a realistic methodology for determination of the Life-Cycle Cost (LCC)-effective optimal seismic retrofit and maintenance strategy of deteriorating bridges. The proposed methodology is based on the concept of minimum LCC which is expressed as the sum of present value of seismic retrofit costs, expected maintenance costs, and expected economic losses with the constraints such as design requirements and acceptable risk of death. The proposed methodology is applied to the LCC-effective optimal seismic retrofit and maintenance strategy of a steel bridge considered as a example bridge in the accompanying study, and various conditions such as corrosion environments and Average Daily Traffic Volumes (ADTVs) are considered to investigate the effects on total expected LCC. In addition, to verify the validity of the developed methodology, the results are compared with the existing methodology. From the numerical investigation, it may be positively expected that the proposed methodology can be effectively utilized as a practical tool for the decision-making of LCC-effective optimal seismic retrofit and maintenance strategy of deteriorating bridges.