• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.587-597
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• 2023

We evaluated the eutrophication of Saemangeum Lake, which causes abnormal growth of algae, using the Carlson index. Eutrophication characteristics of Saemangeum Lake were analyzed. For the study, water quality surveys were conducted at 7 stations in Saemangeum Lake every month in 2021. The concentration of Chl.a was slightly higher in the Mankyeong water system in winter, and slightly higher in the Dongjin water system in spring and summer, but overall, except for some periods, the concentration was similar to or lower than the lake water quality environmental standard of class 3. COD showed water quality similar to or above the lake quality environmental standard of grade 4 in both the Mankyeong and Dongjin water systems in the summer and Autumn. TOC concentrations were within lake water quality standard 3 at all sites. Total phosphorus concentrations exceeded the lake water quality standard of Class 4 and were higher in January and August after rainfall. In the correlation analysis between water quality factors, the correlation of organic matter, total phosphorus, and total nitrogen to salinity was relatively high. This reflected the water quality characteristics of freshwater, brackish water, and seawater areas due to seawater inflow through the drainage gate and freshwater inflow through upstream rivers. According to the characteristics of eutrophication fluctuations in Saemangeum Lake by trophic state index, the indices of Chl.a, SD, and TN showed water quality in the early stage of eutrophication, while the TP index showed a severe eutrophication state. The magnitude of the eutrophication index among water quality components was TSI(TP) > TSI(TN) > TSI(SD) > TSI(CHL) in all water systems. Quadrant analysis of the deviation of TSI(CHL) from TSI(TP) and TSI(SD) on a two-dimensional plane showed that there was no limiting effect of total phosphorus on algal growth in all water systems. In addition, the factors af ecting light attenuation appeared to be dominated by small particulate matter from outside sources.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.85-97
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• 1974

In order to clarify the inducing conditions and cause of sterility in rice plants, 4 varieties were cooled at 3 different levels of temperature combined with 3 different levels of treatment period. And 19 varieties were tested to examine the varietal difference of cold resistance. The results obtained were summarized as follows; 1. There were significant varietal differences in the effect of cooling treatment at meiotic stage. Suwon 213-1 was induced heavy sterility by 3 day cooling treatment at 17.5$^{\circ}C$ whereas Hayayuki, Nongpaik and Jinheung were induced a little sterility by 3 day cooling treatment at 15$^{\circ}C$ and 5 day treatment at 17.5$^{\circ}C$. The per cent of grain fertility was correlated significantly with the delayed days to heading, the degree of panicle extraction (Suwon 213-1, Nongpaik, Jinheung), culm length (Nongpaik, Suwon 213-1), and Auricle distance (Suwon 213-1). The degree of sterility was able to be estimated from the linear regression equation between the degree of panicle extraction (distance from panicle neck to flag leaf) and fertility percentage. In the case of heavy cold damage by the treatment of low temperature at meiotic stage, the rice plant had somewhat lower pollen density per anther, small and ununiform anther and pollen in size, and more sterile pollen grains. Suwon 213-1 showed anthesis in almost all spikelets, while Nongpaik, Jinheung and Hayayuki indicated considerable number of indehisced anther at 5 days after heading. 2. The fertility were not generally higher in cooling treatment at heading stage than at meiotic stage treatment. And significant correlation was found between the percentage of grain fertility treated at above two stages. Nongpaik and Jinheung were not affected in percentage of fertility by 5 day treatment at 15$^{\circ}C$ when these were treated at heading stage. Indehisced anthers were not found in Suwon 213-1 and Hayayuki, but Nongpaik and Jinheung showed more anthers which did not show anthesis 3. There was different varietal response to low temperature which was indicated by the decrease of grain fertility resulted from cooling treatment at meiotic stage. Jaekeun and Jinheung did not show low fertility but Milseong, Suwon 210, Satominoli and Suwon 213-1 showed outstanding decrease in fertility percentage by the cooling treatment at meiotic stage. The varieties which had low fertility were likely to have low pollen density per anther, abnormal anthers, small size po]]en grains and many sterile pollens. 4. Remarkable varietal difference of cold resistance was found in heading stage cooling treatment. Nongpaik, Jinheung, Jaekeun, Paltal, Akibare, Milseung and Palkeong were not affected in grain fertility by cooling treatments but Nonglimna No. 1, Suseong, Hayayuki, Suwon 213-1 and Suwon 210 showed significantly high sterility as treated by cool temperature. Most of the varieties showed higher fertility by cooling treatment at heading stage than meiotic stage but Hayayuki, Suseong and Nonglimna No.1 showed lower fertility when these were treated at heading stage than meiotic stage. There were two grops of varieties in the response to cooling treatment, one was somewhat non-anthesised and the other showed full anthesis. 5. In cold injury test of young seedlings, the result of observation was not accorded with the degree of growth inhibition. As a general, Palkeum and Suseong were highly torelant to cool temperature but Suwon 213-1, Jaekeun, Paltal, Shirogane, Palkeong, Mankyung were highly susceptible. 6. There is no significant correlation between the degree of young seedling cold damage and or the degree of growth retardation at seedling stage and grain fertility resulted from coding treatment both heading and meiotic stage.

• Clinical and Experimental Pediatrics
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• v.50 no.1
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• pp.20-27
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• 2007

Purpose : Child sexual abuse is a significant and serious problem that affects public health and society. Pediatricians are responsible for preventing and detecting sexual abuse of children. The aim of this study was to examine clinical findings of child sexual abuse. Methods : The authors retrospectively studied 292 patients between the ages of 0 and 18 who were referred for evaluation of sexual abuse to the Emergency Department of the National Police Hospital from Oct 1, 2001 to May 5, 2005. Results : Sixty three (21.6 percent) of sexual abuse victims were younger than 6 years of age; 89 (30.5 percent) were 6-12 years of age; and 104 (47.9 percent) were 12-18 years of age. Attack time was the most common between noon and 6 pm. Victims were attacked in their home or nearby (51.4 percent). One hundred fifty six (53.6 percent) offenders were accquaitances, thirty nine (13.4 percent) of whom were family members. The disclosure of attack by parents with abnormal physical symptoms was more common in younger children than in adolescence. Eighty nine (30.5 percent) victims had no specific physical findings, 51 percent had injury to the hymen, 37.3% had injury to external genitalia, and 4 percent had anal injury. One case of gonorrhea and thirteen cases of chlamydia were found. Sperm was found in 19 cases and acid phosphatase was positive in 28 cases. The absence of physical findings and laboratory findings was more common in younger children than in those in adolescence. The time interval from attacks to hospital visits had a significant negative correlation with age. Conclusion : For younger victims, the time interval from attack to hospital visitis was more prolonged. Victims may have no physical evidence of sexual abuse. Therefore, a careful history should be obtained and a through physical examination should be performed. Pediatricians must play a leading role in evaluation and treatment of sexually abused children, considering children,s growth and development. Coordination with other professionals is necessary to provide consultation, medical treatment, and legal assistance for the sexually abused children and families.

• Journal of the Korean Ceramic Society
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• v.39 no.1
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• pp.26-32
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• 2002

The effects of $Nd_2O_3$ addition to $Q{\cdot}f_{0}(GHz)$ ceramics with ${\varepsilon}_r$ of 126, $Q{\cdot}f_{0}(GHz)$ of 2240 and of $68\;ppm/^{\circ}C$ on their microwave properties were investigated. For the addition of 5 wt% $Nd_2O_3$, the dielectric constant (${\varepsilon}_r$) showed maximum value of 131, then decreased with the further addition of $Nd_2O_3$. $Q{\cdot}f_{0}(GHz)$ value was still increased to 3533 with 9 wt% $Nd_2O_3$ addition, it is influenced by densification of grain boundary. With more addition of $Nd_2O_3$ up to 18 wt%, the abnormal grain growth have influence on the decreasing of $Q{\cdot}f_{0}(GHz)$ value. But with the further addition of $Nd_2O_3$ over 25 wt%, the $Q{\cdot}f_{0}(GHz)$ value was again increased by the effect of the second phase ($Nd_2Ti_2O_7$) forming. The temperature coefficient of resonant frequency (${\tau}_f$) was decreased from $+\;68\;ppm/^{\circ}C$ with the addition of $Nd_2O_3$, reached $0\;ppm/^{\circ}C$ at 12 wt% addition, and became negative with the further addition of $Nd_2O_3$. The optimum microwave dielectric properties were obtained for $0.3CaTiO_3-0.7(Li_{1/2}Nd_{1/2})TiO_3$ with 9 wt% $Nd_2O_3$ sintered at $1425^{\circ}C$ for 3 hrs. The dielectric constant (${\varepsilon}_r$), the $Q{\cdot}f_{0}(GHz)$ value, and the temperature coefficient of resonant frequency (${\tau}_f$) were 108, 3533, and $+\;6\;ppm/^{\circ}C$, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.389-398
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• 1984

The effect of N forms ($NO_3{^-}-N$, $NH_4{^+}-N$) and concentrations (4, 8, $16meq/{\ell}$) which were changed at head formation stage on the tip-burn incidence of chinese cabbage was studied under the three levels (0, 8, 16 meq/l) of Ca. All of the plants grown on $NH_4{^+}-N$ showed the symptoms of tip-burn and low yields regardless of Ca levels. Roots of plants grown on $NH_4{^+}-N$ were severely damaged. The pH of the leachate from $NH_4{^+}-N$ pot was decreased to below pH 5. Plants which had been grown on $NH_4{^+}-N$ before the head formation stage, but changed to $NO_3{^-}-N$ were recovered from abnormal growth. But, the reverse showed the tip-burn symptoms. $NH_4{^+}-N$ treatments increased the T-N contents, but lowered K and Ca contents of inner leafblades. Icreased applications of Ca did not affect the T-N and K contents of the inner leafblades. $NH_4{^+}-N$ suppressed Ca translocation into the inner leaves from outer leaves after the head formation stage, but $NO_3{^-}-N$ accelarated it. Ca contents were much lower in leaves showing tip-burn symptoms than in healthy leaves. Internal rot which is a tip-burn symptom occuring after head formation were noted in plants applied with high concentration of $NO_3{^-}-N$ both before and after the head formation stage. Ca contents correlated well with the rates of Ca application, but there was no correlation between ca conents and internal rot incidence. Chinese cabbage tip-burn is not caused by Ca deficiency, as is commonly believed, but rather by the water stress (95% water contents in $NO_3{^-}$-fed plants, 91% in $NH_4{^+}$-fed plants) resulting from root damage caused by ammonium toxicity. Internal rot is also caused by excess applications of nitrogen, and is unaffected by calcium levels.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.2
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• pp.108-125
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• 2015

The agro-climatic index is one of the ways to assess the climate resources of particular agricultural areas on the prospect of agricultural production; it can be a key indicator of agricultural productivity by providing the basic information required for the implementation of different and various farming techniques and practicalities to estimate the growth and yield of crops from the climate resources such as air temperature, solar radiation, and precipitation. However, the agro-climate index can always be changed since the index is not the absolute. Recently, many studies which consider uncertainty of future climate change have been actively conducted using multi-model ensemble (MME) approach by developing and improving dynamic and statistical downscaling of Global Climate Model (GCM) output. In this study, the agro-climatic index of Korean Peninsula, such as growing degree day based on $5^{\circ}C$, plant period based on $5^{\circ}C$, crop period based on $10^{\circ}C$, and frost free day were calculated for assessment of the spatio-temporal variations and uncertainties of the indices according to climate change; the downscaled historical (1976-2005) and near future (2011-2040) RCP climate sceneries of AR5 were applied to the calculation of the index. The result showed four agro-climatic indices calculated by nine individual GCMs as well as MME agreed with agro-climatic indices which were calculated by the observed data. It was confirmed that MME, as well as each individual GCM emulated well on past climate in the four major Rivers of South Korea (Han, Nakdong, Geum, and Seumjin and Yeoungsan). However, spatial downscaling still needs further improvement since the agro-climatic indices of some individual GCMs showed different variations with the observed indices at the change of spatial distribution of the four Rivers. The four agro-climatic indices of the Korean Peninsula were expected to increase in nine individual GCMs and MME in future climate scenarios. The differences and uncertainties of the agro-climatic indices have not been reduced on the unlimited coupling of multi-model ensembles. Further research is still required although the differences started to improve when combining of three or four individual GCMs in the study. The agro-climatic indices which were derived and evaluated in the study will be the baseline for the assessment of agro-climatic abnormal indices and agro-productivity indices of the next research work.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.305-312
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• 1997

Juveniles of black seabream, Acanthopagrus schlegeli were fed with the diets containing 0, 10, 20, 50 and 100 ppm of 3,5,3'-triiodo-1-thyronine $(T_3)$ respectively to assess the effect of this hormone on skeletal development and the change of physiological conditions for 50 days. $(T_3)$ treatment lasted for initial 40 days. Fish were fed the prescribed diet by hand to satiation in $2\~4$ times per day. After an initial 40 days period, skeletal development and abnormality were examined, and after a 50 days period, food intake, hepatosomatic index (HSI), thyroid cell height (TCH) and body proximate composition were also examined. Although toed intake was not different among 0, 10 and 20 ppm, the food intake of black seabream fed with the diets containing 50 and 100 ppm of $T_3$was significantly lower than those of 10 ppm. After the initial 40 days of $T_3$ administration, $T_3$ increased the relative growth of operculum, head, caudal fin and pectoral fin to body length, resulting in severe morphological abnormalities at the highest dose. Black seabream treated with 50 and 100 ppm of $T_3$ had abnormal shapes such as lordosis and opercular curl. The HSI parameters were reversely correlation with the dietary concentration of $T_3$. After the initial 40 days of this experiment, atrophy of thyroid gland was observed in fish administered with 50 and 100 ppm of $T_3$. On the 50th day of this experiment, atrophy of thyroid gland was observed only in the group administered with 100 ppm of $T_3$, and no difference was observed on TCH among the rest fours of experimental groups. At the end of the experiment the whore body proximate analyses indicated that there were significant effects of $T_3$ level on moisture, protein, lipid and ash contents.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.750-756
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• 2008

Supernumerary teeth are frequently found in the anterior portion of the maxilla and develop as a result of abnormal proliferation of the dental lamina during tooth germ formation, caused by genetic or environmental factors. They may result in various complications, such as eruption interference, displacement, rotation of adjacent teeth, diastema, eruption into the nasal cavity, and development of dentigerous cyst. The optimal time for surgical extraction of supernumerary teeth has been a controversial issue. Someone prefer early surgical extraction because supernumerary teeth can cause eruption interference and displacement of adjacent teeth, eventually altering occlusion. Others prefer to delay surgical extraction until $8{\sim}10$ years of age in consideration of root maturation of the adjacent teeth and also patient's behavior. When surgical extraction of supernumerary teeth is postponed, there is possibility that impacted supernumerary teeth in the inverted or horizontal position move toward the nasal cavity, hard palate, or premolar area. When such intraosseous tooth migration is combined with the vertical growth of the maxilla, surgical approach becomes even harder. Therefore, possibility of intraosseous tooth migration should be considered as an important factor when deciding appropriate time for surgical extraction. We are presenting cases of mesiodens which showed intraosseous migration during $6{\sim}7$ years of follow-up period since the first diagnosis had been made at the $2{\sim}3$ years of age.

• Korean Journal of Ecology and Environment
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• v.36 no.1 s.102
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• pp.83-94
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• 2003

Concentrated releases of zinc into water usually results from discharges associated with industrial purpose. The released zinc into soil is corroded and released into water. In aquatic environment, exess zinc is toxic to the organisms and causes the growth inhibition and malformation of them as a heavy metal. In this study, excess zinc toxicity was tested by FETAX (frog embryo teratogenetic assay with Xenopus)as in vivo system. Xenopus embryos at st.9 were exposed to $100{\sim}900\;{\mu}M$ of zinc for 7 days and 81% of individuals were survived in 100 ${\mu}M$, and 25% were survived in 1000M of zinc solution. In external malformations, swelled belly and intestinal dysplasia were common, and all of tested individuals showed these malformations in 200 ${\mu}M$ or higher concentration of zinc. In 400 ${\mu}M$ or higher concentration, all of tested tadpoles showed faded heart. Also, hypo-pigmentation, lens hernia and loose digestive track were very frequently found in 100 ${\mu}M$ of zinc. The histological study with paraffin section of zinc treated tadpoles showed following abnormalities; regeneration of photoreceptor on retina, reduced vitreous chamber in eye, reduction of red blood cells in heart, abnormal liver, swelling of pronephric cell, muscle dysplasia and palatal papilloma. These abnormalities may be caused by the degeneration of mitochondria, inhibition of cell adhesion, and the formation of leghemoglobin by zinc due to the substitution of $Ca^{2+}$ by $Zn^{2+}$. The body length was reduced due to the excess zinc. From a statistical result, body lengths of 300 ${\mu}M$ or higher concentrative g개ups was significantly reduced comparing that of control group. Recently, many spontaneous malformations and reduction of amphibians are reported, From the results of present study, excess zinc mi호t be a factor of amphibian reduction, and the control of zinc discharges is very important.

• Pediatric Infection and Vaccine
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• v.5 no.2
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• pp.221-229
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• 1998

Purpose : The symptom of urinary tract infection in children is non-specific and systemic compared to that of adults. So the diagnosis of UTI in children can be delayed. If UTI in children is not appropriately managed, it may he resulted in renal failure, hypertension, growth failure in adolescence because there are already documented renal scar or urinary tract abnormality in infection period. Especially upper UTI that involve renal parenchyme may be result in fatal complication. The purpose of this study is analyzing the relationship between acute reactive marker and $^{99m}TC$-DMSA renal scan in upper urinary tract infection. Methods : This study included 56 children admitted at Dankook University Hospital Pediatric Department in Jan. 1995~May. 1998. We analyzed quantatively the results of acute reactive marker(CRP, ESR, WBC), pyuria, fever and compared to those of sonographically find ing and $^{99m}TC$-DMSA renal scan. Comparison between groups were performed by the chi-square (x2) test and a p value of less than 0.05 was considered statistically significant. Results : 1) The number of boys less than 1 year of age was larger than that of girls. But the number of boys more than 1 year of age was reversed. 2) The higher me level of reactive marker (CRP, WBC), the more the probability of upper UTI. 3) The higher fever, the more the probability of upper UTI. 4) The more pyuria, the more probability of upper UTI. 5) The more higher the grade of vesicoureteral reflux, the more probability of upper UTI. 6) $^{99m}TC$-DMSA renal scan is more sensitive and more specific diagnostic tool than renal sonogram. Conclusion : The appearance of an abnormal $^{99m}TC$-DMSA renal scan is correlated with acute reactive marker (CRP, ESR, WBC), fever, pyuria. $^{99m}TC$-DMSA renal scan can be a good valuable predictor tool in upper UTI. So we can start early treatment and decrease the incidence of complication of upper urinary tract by above indicators before knowing the result of urine culture. And we can follow up the patients in more good relationships with their parents by telling them the duration of treatment and follow-up plan.