• Title/Summary/Keyword: Significant factors

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Ecological Risk Assessment of Alachlor using Medaka (Oryzias latipes) and Earthworm (Eisenia fetida) (송사리(Oryzias latipes)와 지렁이(Eisenia fetida)를 이용한 Alachlor의 생태 위해성평가)

  • Lee, Chul-Woo;Kim, Hyun-Mi;Yoon, Jun-Heon;Song, Sang-Hwan;Ryu, Ji-Sung;Kim, Eun-Kyoung;Yang, Chang-Yong;Chung, Young-Hee;Choi, Kyung-Hee;Lee, Moon-Soon
    • Korean Journal of Environmental Biology
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    • v.25 no.1
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    • pp.1-7
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    • 2007
  • Medaka(Oryzias latipes) and earthworm(Eisenia fetida) toxicity tests were carried out and ecological risk assessment in water and soil was performed with national monitoring data. NOEC of alachlor was 100μgL1100μgL1 in the medaka early life-stage test. Embryonic development, hatchability and time to hatching of medaka eggs were affected by this chemical. The LC50 and NOEC of alachlor were 94.1mgkg1and55.0mgkg1, respectively, in the earthworm acute toxicity test. The environmental monitoring has been carrying out by NIER since 1999. Exposure levels of alachlor in water and soil were ND0.54μgL1andND0.9μgkg1, respectively, in national monitoring data which had been performed from 2000 to 2004. The measured water and soil exposure levels were applied to evaluate the environmental risk assessment. The PNEC of alachlor in water and in soil were determined as 1μgL1and55.0μgkg1, respectively using the safety factors which were suggested in EU and OECD. The HQs (PEC/PNEC) were determined to be below 1 for both water and soil when the maximum exposure levels (0.54μgL1 in water and 0.9μgkg1 in soil) were applied. Conclusively, our study indicated that there was not significant ecological risk of alachlor in water and soil of our monitoring sites.

Accurate Quality Control Method of Bone Mineral Density Measurement -Focus on Dual Energy X-ray Absorptiometry- (골밀도 측정의 정확한 정도관리방법 -이중 에너지 방사선 흡수법을 중심으로-)

  • Kim, Ho-Sung;Dong, Kyung-Rae;Ryu, Young-Hwan
    • Journal of radiological science and technology
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    • v.32 no.4
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    • pp.361-370
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    • 2009
  • The image quality management of bone mineral density is the responsibility and duty of radiologists who carry out examinations. However, inaccurate conclusions due to lack of understanding and ignorance regarding the methodology of image quality management can be a fatal error to the patient. Therefore, objective of this paper is to understand proper image quality management and enumerate methods for examiners and patients, thereby ensuring the reliability of bone mineral density exams. The accuracy and precision of bone mineral density measurements must be at the highest level so that actual biological changes can be detected with even slight changes in bone mineral density. Accuracy and precision should be continuously preserved for image quality of machines. Those factors will contribute to ensure the reliability in bone mineral density exams. Proper equipment management or control methods are set with correcting equipment each morning and after image quality management, a phantom, recommended from the manufacturer, is used for ten to twenty-five measurements in search of a mean value with a permissible range of ±1.5 set as standard. There needs to be daily measurement inspections on the phantom or at least inspections three times a week in order to confirm the existence or nonexistence of changes in values in actual bone mineral density. in addition, bone mineral density measurements were evaluated and recorded following the rules of Shewhart control chart. This type of management has to be conducted for the installation and movement of equipment. For the management methods of inspectors, evaluation of the measurement precision was conducted by testing the reproducibility of the exact same figures without any real biological changes occurring during reinspection. Bone mineral density inspection was applied as the measurement method for patients either taking two measurements thirty times or three measurements fifteen times. An important point when taking measurements was after a measurement whether it was the second or third examination, it was required to descend from the table and then reascend. With a 95% confidence level, the precision error produced from the measurement bone mineral figures came to 2.77 times the minimum of the biological bone mineral density change. The value produced can be stated as the least significant change (LSC) and in the case the value is greater, it can be stated as a section of genuine biological change. From the initial inspection to equipment moving and shifter, management must be carried out and continued in order to achieve the effects. The enforcement of proper quality control of radiologists performing bone mineral density inspections which brings about the durability extensions of equipment and accurate results of calculations will help the assurance of reliable inspections.

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Understanding of Phytoplankton Community Dynamics Through Algae Bioassay Experiment During Winter Season of Jinhae bay, Korea (생물검정실험을 통한 동계 진해만 식물플랑크톤의 군집 변동 특성 파악)

  • Hyun, Bong-Gil;Shin, Kyoung-Soon;Kim, Dong-Sun;Kim, Young-Ok;Joo, Hae-Mi;Baek, Seung-Ho
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.16 no.1
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    • pp.27-38
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    • 2011
  • The distributions of phytoplankton assemblages and environmental factors in Jinhae Bay and their relationships were investigated to estimate the potential limiting nutrient for phytoplankton growth and community structure. In situ algal bioassay experiments were also conducted to assess the species-specific characteristics in phytoplankton responses under different nutrient conditions (control, N(+) and P(+) treatment). During the study periods, bacillariophyceae and cryptophyceae occupied more than 90% of total phytoplankton assemblages. Phytoplankton standing crops in the inner part of Masan Bay were higher than that of Jinhae Bay. The DIN:DIP ratio, pH and transparency showed the significant positive correlation with phytoplankton biomass. According to cluster and multidimensiolnal scaling (MDS) analysis based on phytoplankton community data from each station, the bay was divided into three groups. The first group included stations from the south-western part of Jinhae bay where cryptophyta species were dominated. The second group was distinguished from inner stations in Masan Bay. These stations showed low transpancy and high DIN:DIP ratio. The other cluster included the stations from the eastern part and central part of Jinhae Bay, which was characterized by the high DSi:DIP ratio and dominant of diatom species. Phosphorous (P) was limited in Masan Bay due to significantly increases in the phytoplankton abundances. Based on stoichiometric limitation and algal bio-assay in Jinhae Bay, nitrogen (N) was a major limiting factor for phytoplankton production. However, silicate (Si) was not considered as limiting factor, since Si/DIN and Si/P ratio and absolute concentration of nutrient did not create any potential stoichiometric limitation in the bay. This implies that high Si availability in winter season contributes favorably to the maintenances of diatom species.

Relation between Helicobacter pylori Infection and Socioeconomic Status in Korean Adolescents (Helicobacter pylori 감염과 사회경제적 요인에 대한 연구)

  • Jung, Min-Kyong;Kwon, Young-Se;Choe, Hyon;Choe, Yon-Ho;Hong, Yun-Chul
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.3 no.1
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    • pp.17-22
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    • 2000
  • Purpose: This study was conducted to evaluate the association between H. pylori infection and socioeconomic status and to determine the current prevalence of H. pylori infection in Korean adolescents. Methods: A structured questionnaire was sent to the children's parents to obtain demographic information on the parents and environmental information. Of the 532 questionnaires sent out, 375 (70.5%; 170 girls and 205 boys) were returned. Their ages ranged from 10 to 15 years (mean, 12.9 years). After collecting blood samples, we measured serum IgG antibody to H. pylori using ELISA method. The association of risk factors such as age, sex, socioeconomic class, type of house, and crowding index with H. pylori infection were analyzed by multiple regression analysis. Socioeconomic status was estimated from the parents' education and occupation using a modified Hollingshead index. Results: The prevalence rate of H. pylori infection was 16.8% (63/375). It increased with age (10.3% at 10~11 years, 15.9% at 12~13 years, and 20.7% at 14~15 years). The H. pylori infection was inversely related to the socioeconomic class (6.3% for the upper class, 16.0% for the middle class, and 20.0% for the lower calss). Crowding condition and type of house did not affect significantly on seroprevalence of H. pylori infection. After logistic regression, we found that the odds ratio for age was 2.2 (95% confidence interval 0.9~5.4), and for socioeconomic status, 3.6 (95% confidence interval 0.5~28.9). Conclusion: The prevalence of H. pylori infection in Korean adolescents was 16.8%. It related inversely to socioeconomic status but was not statistically significant. Socioeconomic status based on parents' education and occupation seemed to affect more on H. pylori seroprevalence than crowding or type of house did.

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Clinical Features of Cricopharyngeal Incoordination in Newborns and Infants (신생아 및 영아기 윤상인두 협조불능의 임상적 고찰)

  • Han, Young-Mi;Park, Jae-Hong
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.11 no.2
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    • pp.116-121
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    • 2008
  • Purpose: Cricopharyngeal incoordination is a rare cause of swallowing difficulties in newborns and infants; it is characterized by delayed pharyngeal contractions related to cricopharyngeal relaxation. Dysphagia and repeated aspiration are common findings despite normal sucking. We conducted this study to assess the clinical features of cricopharyngeal incoordination in newborns and infants. Methods: An analysis of the clinical data from 17 patients with cricopharyngeal incoordination who were admitted to the Department of Pediatrics, Pusan National University Hospital, between 2000 and 2006 was conducted retrospectively. The diagnosis of cricopharyngeal incoordination was established by the clinical characteristics and the videofluoroscopic swallowing studies. Results: The male to female ratio was 1:1.1 (males 8, females 9) the age range 1 to 60 days. The body weight of 11 patients (64.7%) was less than the 10th percentile at diagnosis. Six patients (35.3%) were born prematurely. The associated anomalies or diseases were chromosomal anomaly (2 cases), congenital heart disease (3 cases), and laryngomalacia, hypoxic brain damage or neonatal seizures (1 case each). The chief complaints of patients were recurrent aspiration pneumonia (10 cases), feeding difficulty (9 cases), dyspnea (4 cases), and chocking (4 cases). The severity of aspiration on the videoesophagogram or esophagogram was mild in 12 cases. The correlation between the severity of aspiration and the duration of tube feeding after the diagnosis was significant (p<0.05). Conclusion: Cricopharyngeal incoordination should be considered in the differential diagnosis of newborns and infants, without known risk factors associated with swallowing dysfunction, when they present with unexplained respiratory problems. Although the prognosis of cricopharyngeal incoordination is good, early diagnosis and tube feeding are recommended to prevent the complications associated with this disorder.

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Early and Late Bowel Complication Following Irradiation of Cancer of the Uterine Cervix (자궁경부암의 고선량 치료후의 장관 합병증)

  • Kim Myung Se;Kim Kyung Ae;Kim Sung Kyu;Shin Sei One;Lee Sung Ho;Chang Jae Chun
    • Radiation Oncology Journal
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    • v.7 no.1
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    • pp.59-70
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    • 1989
  • Cervix cancer is the most common female cancer in Korea. In spite of their relatively local invasive tendency, still 44% of patient will develop recurrent cancer. This result suggests that more aggressive local treatment may increase the cure rate but increased complication risk also cannot be avoidable. Various institutions proposed different treatment regimen, but recommended dose were about 4500 cGy for whole pelvis and 8000 cGy at point A, even though they agreed that those doses may not be satisfactory for control of bulky disease. 96 cases of invasive cervical cancer, treated with postoperative or primary radiation therapy were analyzed to determine the complication rate and prognostic factor in our treatment regimen Which is 5500\~1000CGy higher than Other institution. Mean follow up duration was 21 months. Symptomatic patients including mild but persistent abdominal discomfort was 46%, but only 1 patient (1%) had operative treatment because of incomplete obstruction of small bowel. Most symptoms appeared within 12 months and most common complaints were frequent bowel movement. Barium enema and sigmoidoscopy were performed for persistent symptomatic patients. Only one patient had abnormal finding in barium enema which showed inefficiency of this method for detecting bowel complication. Patient's age, total tumor dose, total TDF, rectal dose were not significant risk factors for complication, but boost dose, previous history of operation had some relationship with complication risk. Even though dose of point A and rectum is 500\~1,000cGy higher than other institution, such a low rate of severe complications may suggest that fear of complications should not be overestimated than cure rate and the possibility of more aggressive treatment for better local control should not be underestimated.

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A Study on groundwater and pollutant recharge in urban area: use of hydrochemical data

  • Lee, Ju-Hee;Kwon, Jang-Soon;Yun, Seong-Taek;Chae, Gi-Tak;Park, Seong-Sook
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2004.09a
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    • pp.119-120
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    • 2004
  • Urban groundwater has a unique hydrologic system because of the complex surface and subsurface infrastructures such as deep foundation of many high buildings, subway systems, and sewers and public water supply systems. It generally has been considered that increased surface impermeability reduces the amount of groundwater recharge. On the other hand, leaks from sewers and public water supply systems may generate the large amounts of recharges. All of these urban facilities also may change the groundwater quality by the recharge of a myriad of contaminants. This study was performed to determine the factors controlling the recharge of deep groundwater in an urban area, based on the hydrogeochemical characteristics. The term ‘contamination’ in this study means any kind of inflow of shallow groundwater regardless of clean or contaminated. For this study, urban groundwater samples were collected from a total of 310 preexisting wells with the depth over 100 m. Random sampling method was used to select the wells for this study. Major cations together with Si, Al, Fe, Pb, Hg and Mn were analyzed by ICP-AES, and Cl, N O3, N H4, F, Br, S O4and P O4 were analyzed by IC. There are two groups of groundwater, based on hydrochemical characteristics. The first group is distributed broadly from Ca-HC O3 type to Ca-C1+N O3 type; the other group is the Na+K-HC O3 type. The latter group is considered to represent the baseline quality of deep groundwater in the study area. Using the major ions data for the Na+K-HC O3 type water, we evaluated the extent of groundwater contamination, assuming that if subtract the baseline composition from acquired data for a specific water, the remaining concentrations may indicate the degree of contamination. The remainder of each solute for each sample was simply averaged. The results showed that both Ca and HC O3 represent the typical solutes which are quite enriched in urban groundwater. In particular, the PCO2 values calculated using PHREEQC (version 2.8) showed a correlation with the concentrations of maior inorganic components (Na, Mg, Ca, N O3, S O4, etc.). The pCO2 values for the first group waters widely ranged between about 103.0 atm to 101.0 atm and differed from those of the background water samples belonging to the Na+K-HC O3 type (<103.5 atm). Considering that the pCO2 of soil water (near 101.5 atm), this indicates that inflow of shallow water is very significant in deep groundwaters in the study area. Furthermore, the PCO2 values can be used as an effective parameter to estimate the relative recharge of shallow water and thus the contamination susceptibility. The results of our present study suggest that down to considerable depth, urban groundwater in crystalline aquifer may be considerably affected by the recharge of shallow water (and pollutants) from an adjacent area. We also suggest that for such evaluation, careful examination of systematically collected hydrochemical data is requisite as an effective tool, in addition to hydrologic and hydrogeologic interpretation.ion.ion.

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A Study on Knowledge, Attitude and Behavior to Sexuality in Middle School Students (중학생의 성에 대한 지식, 태도, 행위에 관한 조사연구)

  • Cha, Eun-Seok
    • Journal of the Korean Society of School Health
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    • v.12 no.2
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    • pp.357-375
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    • 1999
  • The purpose of this study is to find out methods to control, regulate and prevent sexual violence and provide guidelines for sex education in middle school. This study was conducted to examine factors in relation to sexuality, attitudes toward women, experience of sexual contact, frequencies and kinds of pornography with which they had contact, and sex education. For the data collection, a survey was conducted from September 25 to October 1, 1997 by using prepared questionnaires. Questionnaires were given to 503 students from three different kinds of middle schools in Seoul, Boys, Girls, and Coeducation schools. The data analyses used a PC-SAS. Each item was examined by frequencies and percentage. To compare Boys with Girls, I applied a T-test. In addition, with the kinds of school type, I applied anANOVA, χ2. Moreover, For investigating and analyzing each category, I categorized knowledge and attitude of sexuality, with precautionary measures of sexual violence. After that I applied T-test, ANOVA, and a Pearson's correlation for each category. The instruments of this study consisted of 9 domains. (1) General characteristics of the respondents (2) 9 questions about the interaction between he/she and his/her parent. (3) 12 questions, concerning A Scale for Attitudes of Adolescents Toward women(AWSA). (4) 26 questions related to sexual knowledge. (5) 25 questions about sexual attitude (6) strategies for prevention of sexual violence-33 questions (7) 5 questions related to sexual behavior (8) the experience of contact with pronography. (9) the experience of sex-education. The major results were summarized as follows; 1. Like many researches, This study shows that the girls are more eqalitarian than boys. The girls mean (40.90±3.67) is significantly higher than boys (34.72±3.77). Most Koreans have believed that there are many differences between men's roles and women's ones, because of confucianism which had been implied in most thought and ideas since the Lee dynasty. Therefore, the result is not surprising at all. 2. Most students answered correctly the questions of sexual knowledge. The girl's score was higher (Mean±SD : 48.88±2.39) than the boys' (Mean±SD : 46.95±3.90)(p 0.001). Nevertheless, the hypothesis that sexual knowledge influences sexual attitude and its behavior was rejected. 3. When twenty-five questions were asked about sexual attitude, the girl students investigated were found to have a more propre sexual attitude than that of the boys. A significant difference was found between boys and girls(p=0.001). The result shows that a person who has more experience in viewing pornography and who smokes will have a more distorted view of sexuality. 4. There are many students who have experienced of sexual contact. They need to take a sex education program about contraception and prevention of sexually transmitted diseases. Systematic and concrete sex education is one way to lead them to proper sexual behavior. 5. Most respondents rejected stereotyped attitudes towards women. Boys, however, were more likely to accept stereotypes of Women. The girl's mean(Mean±SD : 40.90±3.67) is higher than the boys(Mean±SD : 34.72±3.77)(p=0.0001). 6. Many boys ignored the rules for prevention of sexual violence. A boy or a girl who has more experience of sexual contact over kiss and sex-typed neglected the rules, too(p=0.001). Today, there is increasing juvenile delinquency related to sexuality. This study provided the basic material for a preventive education system. I believe that a systematic and concrete sex education system can be helpful for adolescents and promote their responsibility as well as cultivate morality about sexuality. As a result, juvenile delinquency can be decreased. This study is basically aimed to provide information for a prevenative education system of sexual violence. Further research is recommended to evaluate programs in schools.

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Middle School Students' Perception of Body Image and Allowance for Plastic Surgery (중학생의 신체상 지각수준과 성형수술 허용도)

  • Bae, Jin-Ju;Park, Young-Soo
    • The Journal of Korean Society for School & Community Health Education
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    • v.5
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    • pp.25-42
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    • 2004
  • This study set out to investigate the relations between middle school students' perception of body image and their allowance for plastic surgery, to understand their perception of body image and desire for plastic surgery, and provide some data needed to warn against reckless plastic surgery and guide the students effectively. For those purposes, an examination was conducted of the relationships between the individual characteristics and perception levels of body image, the individual characteristics and allowance for plastic surgery, and perception levels of body image and allowance for plastic surgery. The subjects were drawn from sour middle schools located in two regions of Gyeonggi Province. Total 922 boys and girls were surveyed on a questionnaire, which was developed based on the pretest of previous literature, reviewed for appropriateness, and tested for reliability and reasonableness. The body image on the five scale was greater as the perception level was higher. The allowance for plastic surgery was also greater as the scores were more. The findings were as follows: First, the relationships between individual characteristics and perception levels of body image were examined. The third graders showed the highest perception level, being followed by the first and second graders. The girls were more perceptive than the boys, and those who were extrovert were more perceptive than those who were introvert. Those students whose parents earned 2 million won or more a month and who adapted themselves to the environmental changes had a higher perception level. In a word, the girls from the middle class that were well adapted, felt happy, and were extrovert had a higher perception level of body image. Second, the connections between individual characteristics and allowance for plastic surgery were investigated. The third graders were the most admissive of plastic surgery, followed by the second and first graders. That is, the upper graders were more admissive of plastic surgery. In addition, the girls were more admissive than the boys, and those who were extrovert were more than those who were introvert. There were no significant differences according to the monthly income of the parents, grades, adaptability to surroundings, and happiness, which results almost resembled the findings of a study conducted on adults. Third, there were negative correlations found between the perception levels of body image and the allowance for plastic surgery. To elaborate, the higher the perception levels were, the lower the allowance was, and vice versa. As for the items, the subjects showed more allowance for plastic surgery when they scored less in the item of caring about appearance, importance of looking pretty to others, and efforts to improve appearance. When they had a low value of body and easily felt tired, they were highly acceptive of plastic surgery. The allowance for plastic surgery was also great when their perception was much of how healthy they felt, how important they felt about their bodies, how they were satisfied with their current appearances, how they evaluated the appearance of others, how much they were satisfied physically, and how much demanding they were for physical changes. Meanwhile, there were no correlations between the allowance and physical attraction, the degree for one's activities to be hindered, and sickness. In short, the demand for plastic surgery was 41% for the girls and 20.2% for the boys. Just as the study on adults reported, those who had a low or negative perception of body image were more acceptive of plastic surgery. The middle school students were generally positive about their bodies with the lowest perception level at 2.91 and the highest at 3.21. Their individual allowance for plastic surgery was related to their individual body images, which were in turn affected by the mass communication, surrounding environments, and social values. Thus it's necessary for the entire society to try to improve or change the overall perception. Helping measures should be taken so that the students can form right sense of values about their bodies, avoid the obsession with appearance and appearance-based evaluation, and exercise righteous criteria against humans beings and things. In conclusions, the following suggestions were made: they need to develop such questionnaires or tools as can measure the body image of teens and fit the reality. Moreover, body image improvement programs should be more diverse and more applicable to teens. Despite the consistent reports that prove the correlations between body image and plastic surgery, there has been little effort to apply such factors as experience of the life of the disabled, volunteer activities for the disabled and at the hospitals, and others that can induce changes to body image to the body image improvement programs. In the future, comparative research should be carried out on body image and plastic surgery.

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Physical Properties and Apparent Thermal Diffusivity of the Soils where Soil Temperature is Measured Regularly (기상청(氣象廳) 지온(地溫) 측정(測定) 토양(土壤)의 물리적(物理的) 성질(性質)과 겉보기 열확산(熱擴散) 계수(係數) 산정(算定))

  • Song, Kwan-Cheol;Jung, Yeong-Sang;Kim, Byung-Chan;Ahn, Yoon-Soo;Um, Ki-Tae
    • Korean Journal of Soil Science and Fertilizer
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    • v.25 no.3
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    • pp.220-230
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    • 1992
  • Soil temperature is one of the important environmental factors which control all the physical, chemical and biological processes in soil including germination and root growth of plants and other organisms living in the soil ecosystem. Soil water and nutrient availability and mobility are temperature dependent. Soil temperature change is depended primarily upon energy exchange in soil surface, meteorological variance and physical properties of the soils which are closely related to heat transfer mechanism. In this study physical properties including bulk density, soil texture and organic matter content were measured and thermal diffusivity on the soils was calculated. Soil samples from the 66 meteorological stations under the Korea Meteorology were collected and the physical parameters were measured. To obtain relationship between thermal diffusivity and soil water content a heat probe thermal diffusivity measurement apparatus was designed and used in this experiment. According to the survey on soil physicsal properties on the 66 meteorological stations, the 52% of the surface soil texture were sandy loam and laomy sand or sand, 38% were loam and silty loam, and 10% were clay loam and silty clay loam. The bulk density which was closely related with thermal properties showed average of 1.41g/cm3 for sandy soils, 1.33g/cm3 for loam and silty loam soils, and 1.21g/cm3 for clay loam and silty clay loam soils. The apparent thermal diffusivity of the upper layer from 0 to 30cm ranged from 1.16 to 8.40×103cm3/sec with average of 3.53×103cm3/sec. The apparent thermal diffusivities of the Jeju soils of which organic matter contents were high and the bulk densities were low were near 2×103cm3/sec. The thermal diffusivity of snow measured in Chuncheon ranged from 0.822 to 2.237×103cm3/sec. The damping depth calculated from the thermal diffusivity ranged from 5.92 to 13.65cm for daily basis and 124 to 342cm for yearly basis. The significant regression equation to estimate thermal diffusivity with bulk density and soil water content was obtained by the heat probe in laboratory.

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