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Pesticide Residues Monitoring of Medicinal Herbs in Seoul (서울지역 유통 한약재 중 잔류농약 실태조사)

  • Choi, Young-Hee;Park, Sung-Kyu;Kim, Ouk-Hee;Seoung, Hyun-Jung;Han, Sung-Hee;Lee, Young-Ju;Jeong, Hee-Jeong;Kim, Yun-Hee;Jo, Han-Bin;Yu, In-Sil;Han, Ki-Young;Chae, Young-Zoo
    • The Korean Journal of Pesticide Science
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    • v.15 no.4
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    • pp.335-349
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    • 2011
  • 100 residual pesticides in 1,565 medicinal herbs being on sale in Seoul was analyzed by a simultaneous multiresidue method. The recovery ratio was 71.0~119.7%. The detection rate of pesticide residues was 5.3% and the rate of excess to Maximum Residue Limits (MRLs) was 0.9% of the total samples. The medicinal herbs which had the high detection rate of residual pesticides were Alismatis Rhizoma, Citri Unshii Pericarpium, Lycii Fructus and Zyzyphi Fructus. The medicinal herbs detected pesticide over Maximum Residue Limits (MRLs) were Alismatis Rhizoma (4), Cnidii Rhizomain (4), Chrysanthemi Zawadski Herba (1), Citri Unshii Pericarpium (1), Lycii Radix Cortex (1), Menthae Herba (1), Schisandrae Fructus (1) and Taraxaci Herba (1). The residual pesticides which had the high detection frequency were cypermethrin, chlorpyrifos, phenthoate, endosulfan, isoprothiolane, chlorothalonil and chlorfenapyr. Estimated Daily Intake (EDI) of detected pesticides was compared to Acceptable Daily Intake (ADI) in order to assess risk. Ethoprophos detected in Cnidii Rhizomain showed the highest %ADI, 26.85. And pyraclofos and endosulfan in Cnidii Rhizomain, endosulfan and isoprothiolane in Alismatis Rhizoma and cyprodinil in Taraxaci Herba showed more than 1 %ADI, but others showed below 1 %ADI.

Performance of Investment Strategy using Investor-specific Transaction Information and Machine Learning (투자자별 거래정보와 머신러닝을 활용한 투자전략의 성과)

  • Kim, Kyung Mock;Kim, Sun Woong;Choi, Heung Sik
    • Journal of Intelligence and Information Systems
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    • v.27 no.1
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    • pp.65-82
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    • 2021
  • Stock market investors are generally split into foreign investors, institutional investors, and individual investors. Compared to individual investor groups, professional investor groups such as foreign investors have an advantage in information and financial power and, as a result, foreign investors are known to show good investment performance among market participants. The purpose of this study is to propose an investment strategy that combines investor-specific transaction information and machine learning, and to analyze the portfolio investment performance of the proposed model using actual stock price and investor-specific transaction data. The Korea Exchange offers daily information on the volume of purchase and sale of each investor to securities firms. We developed a data collection program in C# programming language using an API provided by Daishin Securities Cybosplus, and collected 151 out of 200 KOSPI stocks with daily opening price, closing price and investor-specific net purchase data from January 2, 2007 to July 31, 2017. The self-organizing map model is an artificial neural network that performs clustering by unsupervised learning and has been introduced by Teuvo Kohonen since 1984. We implement competition among intra-surface artificial neurons, and all connections are non-recursive artificial neural networks that go from bottom to top. It can also be expanded to multiple layers, although many fault layers are commonly used. Linear functions are used by active functions of artificial nerve cells, and learning rules use Instar rules as well as general competitive learning. The core of the backpropagation model is the model that performs classification by supervised learning as an artificial neural network. We grouped and transformed investor-specific transaction volume data to learn backpropagation models through the self-organizing map model of artificial neural networks. As a result of the estimation of verification data through training, the portfolios were rebalanced monthly. For performance analysis, a passive portfolio was designated and the KOSPI 200 and KOSPI index returns for proxies on market returns were also obtained. Performance analysis was conducted using the equally-weighted portfolio return, compound interest rate, annual return, Maximum Draw Down, standard deviation, and Sharpe Ratio. Buy and hold returns of the top 10 market capitalization stocks are designated as a benchmark. Buy and hold strategy is the best strategy under the efficient market hypothesis. The prediction rate of learning data using backpropagation model was significantly high at 96.61%, while the prediction rate of verification data was also relatively high in the results of the 57.1% verification data. The performance evaluation of self-organizing map grouping can be determined as a result of a backpropagation model. This is because if the grouping results of the self-organizing map model had been poor, the learning results of the backpropagation model would have been poor. In this way, the performance assessment of machine learning is judged to be better learned than previous studies. Our portfolio doubled the return on the benchmark and performed better than the market returns on the KOSPI and KOSPI 200 indexes. In contrast to the benchmark, the MDD and standard deviation for portfolio risk indicators also showed better results. The Sharpe Ratio performed higher than benchmarks and stock market indexes. Through this, we presented the direction of portfolio composition program using machine learning and investor-specific transaction information and showed that it can be used to develop programs for real stock investment. The return is the result of monthly portfolio composition and asset rebalancing to the same proportion. Better outcomes are predicted when forming a monthly portfolio if the system is enforced by rebalancing the suggested stocks continuously without selling and re-buying it. Therefore, real transactions appear to be relevant.

Understanding Public Opinion by Analyzing Twitter Posts Related to Real Estate Policy (부동산 정책 관련 트위터 게시물 분석을 통한 대중 여론 이해)

  • Kim, Kyuli;Oh, Chanhee;Zhu, Yongjun
    • Journal of the Korean Society for Library and Information Science
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    • v.56 no.3
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    • pp.47-72
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    • 2022
  • This study aims to understand the trends of subjects related to real estate policies and public's emotional opinion on the policies. Two keywords related to real estate policies such as "real estate policy" and "real estate measure" were used to collect tweets created from February 25, 2008 to August 31, 2021. A total of 91,740 tweets were collected and we applied sentiment analysis and dynamic topic modeling to the final preprocessed and categorized data of 18,925 tweets. Sentiment analysis and dynamic topic model analysis were conducted for a total of 18,925 posts after preprocessing data and categorizing them into supply, real estate tax, interest rate, and population variance. Keywords of each category are as follows: the supply categories (rental housing, greenbelt, newlyweds, homeless, supply, reconstruction, sale), real estate tax categories (comprehensive real estate tax, acquisition tax, holding tax, multiple homeowners, speculation), interest rate categories (interest rate), and population variance categories (Sejong, new city). The results of the sentiment analysis showed that one person posted on average one or two positive tweets whereas in the case of negative and neutral tweets, one person posted two or three. In addition, we found that part of people have both positive as well as negative and neutral opinions towards real estate policies. As the results of dynamic topic modeling analysis, negative reactions to real estate speculative forces and unearned income were identified as major negative topics and as for positive topics, expectation on increasing supply of housing and benefits for homeless people who purchase houses were identified. Unlike previous studies, which focused on changes and evaluations of specific real estate policies, this study has academic significance in that it collected posts from Twitter, one of the social media platforms, used emotional analysis, dynamic topic modeling analysis, and identified potential topics and trends of real estate policy over time. The results of the study can help create new policies that take public opinion on real estate policies into consideration.

The Transition of Production, Consumption and Price of Non-ferrous Metals (비철금속(非鐵金屬)의 생산(生産), 소비(消費), 시세(時勢)의 추이(推移))

  • Moon, W.J.
    • Economic and Environmental Geology
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    • v.2 no.3
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    • pp.1-25
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    • 1969
  • In considering the mining industry, it is necessary to study the production, consumption and price of ore and metals in every country of the world in order to determine the trend of the industry in the present and for the future. This study is necessary especially for exporting domestically produced are which is in excess of domestic consumption and for importing are, or metal where local production does not meet domestic demand. It will be treated of Au, Ag, Cu, Pb, Zn, W, Mo, which are the most important non-ferrous metals, and which greatly affect the mining industry of Korea. The presentation will concern itself only with the free world. About 1, 200 ton of gold are produced annually with little fluctiation in recent years. Most of the gold produced is consumed by advanced countries for industrial uses as well as for producing precious objects. The U.S.A. expends yearly about four times its domestic production and Japan about three times its domestic production for industry and arts. Because of the instability of the currency of the U.S.A., England and France, recently, the price of gold has been $ 41-42 per ounce, whereas the official price is $35.00 per ounce. It will be expected that the official price will be raised in the near future. As for silver, about 6,500 tons are produced annually with no special fluctuation change in recent years. However, the annual consumption is about 14,000 ton, so the supply and demand is extremely unbalanced. The shortage is made up by the sale of the U.S. treasury's reserve stock and the reclaiminig of silver from coins and other scrap. As the Treasury'S reserves will be exhausted in a year or two, the price of silver which is $1. 64 per ounce, will go up drastically in about a year. As for copper, 5,257,000 ton's were mined in 1966. It's production is being increased about 5% annually. However, consumption exceeds production by about 100,000 ton a year. The recent Foreign refinery copper price in the U.S.A is $ 60 per pound. The supply of copper being insufficient to meet international demands, the price will go up and with no prospect of being lowered in the near future even with the slight annual increase in production. About 2,100,000 to 2,200,000 tons of lead are produced annually. Consumption exceeds production by about 50,000-60,000 tons annually. The current price of lead in New York is $ 155 per pound. As the supply of lead is internationally stable, It will be believed that there will be no significant change in its price in the near future. In 1967, 3,926,000 tons of Zinc were produced. There is annual increase of 4-7% in production. The annual consumption exceeds production by 100,000 to 200,000 tons. The current zinc price in the St. Louis market inthe U.S.A. is $ 145 per pound. Even though its supply is stable and sufficient world wide, the consumption rate will increase at a faster pace than before; hence, the price will slowly go up. Tungsten mines yield about 11,000 tons a year. Its production has been relatively constant in the past few years. The amount of its consumption increases slowly world wide, but in the free world· there has been a slight annual decrease. However, since Red China has not been exporting their tungsten to other countries for several months, the price on the London market of S.T.U. of $Wo_3$ has increased to $ 44~46. Should Red China begin to export actively again the price will drop to $ 40~42. In 1967, 56,000 tons of Molybdenum were produced. Production exceeds consumption by 200,000 -30,000 tons annually. The current price in the U.S.A. is $ 1.72 per Mo pound. Since the rate of production in the U.S.A. is on the increase with large amounts of ore reserve, the price of molubdenum should not go up.

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Growth and Morphological Charactersistics of Soybean Sprouts Treated with Leaf Extracts of Thea sinensis L. and Eucommia ulmoides Oliver (녹차와 두충 잎 추출물 처리에 따른 콩나물의 생장 및 형태적 특징)

  • Kang, Jin-Ho;Park, Cheol-Jong;Yoon, Soo-Young;Jeon, Seung-Ho;Her, Chang-Young
    • Korean Journal of Medicinal Crop Science
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    • v.13 no.1
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    • pp.11-16
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    • 2005
  • Soybean sprouts presoaked to leaf extracts were on sale as taking a growing concern about wellbeing foods. The study was carried out to compare the effects of culture period after presoaking tea (Thea sinensis L.) and hard rubber tree (Eucommia ulmoides Oliver) leaf extracts on lateral root formation, growth and morphological characters of the sprouts. Seeds of three cultivars, Pungsannamulkong, Sowonkong and Junjery, were imbibed for 5 hours into 10% solutions immediately before 5, 6 and 7 day cultures. The cultured sprouts were classified into 4 categories to calculate their composition rates on the base of hypocotyllengths; >7 cm (A),4 to 7 cm (B),< 4 cm (C) and not germinated (D), and their morphological characters, fresh and dry weights were measured. Rate of A was the lowest in Junjery of the three cultivars, while that of C showed reverse result compared to A. Similar results to that of A were observed between the three cultivars in sprout length including hypocotyl and root, diameters in middle and hook parts of hypocotyl, total fresh and dry weights. Regardless of tea and hard rubber tree leaf extract treatments, longer culture periods increased rate of A due to decrements of B, C and D, and also did the growth and the morphological characters mentioned above. Although longer culture periods reduced the increment of lateral roots, the latter treatment was more delayed in their formation and less in the roots per sprout than the former one. The growth and the morphological characters above were less in the latter treatment than in the former one in general, meaning that hard rubber tree leaf extract could more repress growth of soybean sprouts than tea leaf extract.

Economic Analysis on a PV System in an Apartment Complex (공동주택 태양광발전 시스템의 경제성 평가)

  • Kim, Jin-Hyung
    • Journal of Climate Change Research
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    • v.1 no.2
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    • pp.163-177
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    • 2010
  • This study analyzes the economies of photovoltaic systems in an apartment complex of 1,185 households, in cases of feed-in tariff and subsidy for solar home program of the government. When including the revenue only from electricity sales, NPVs of subsidy and that of feed-in tariff are -560 million KRW and -87 million KRW respectively. With the avoided social cost included without the revenues from CERs, NPVs of subsidy and feed-in tariff are -556 million KRW and -84 million KRW respectively. With the revenues from CERs, NPV of subsidy is -526 million KRW and NPV of feed-in tariff is -54 million KRW. As results of sensitivity analysis based on the changes in capital costs and discount rates, while all scenarios with subsidy including the revenues from CERs are not commercially viable, all scenarios with feed-in tariff exclusive of the revenues from CERs are commercially viable when discount rate is less than 7.2% or capital cost is less than 6,840 thousand KRW/kW. In the cases that include the avoided social cost, while all scenarios with subsidy including the avoided social cost as well as the revenues from CERs are not commercially viable, all scenarios with feed-in tariff are commercially viable without the revenues from CERs when discount rate is less than 7.2% or capital cost is less than 6,856 thousand KRW/KW. The results indicate that the changes in discount rates do not influence the revenues from CERs, but the revenues from electricity sale. Considering that the number of apartment complex and the positive environmental and social benefits from PV system, government needs to promote its diffusion.

A Study on the Buyer's Decision Making Models for Introducing Intelligent Online Handmade Services (지능형 온라인 핸드메이드 서비스 도입을 위한 구매자 의사결정모형에 관한 연구)

  • Park, Jong-Won;Yang, Sung-Byung
    • Journal of Intelligence and Information Systems
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    • v.22 no.1
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    • pp.119-138
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    • 2016
  • Since the Industrial Revolution, which made the mass production and mass distribution of standardized goods possible, machine-made (manufactured) products have accounted for the majority of the market. However, in recent years, the phenomenon of purchasing even more expensive handmade products has become a noticeable trend as consumers have started to acknowledge the value of handmade products, such as the craftsman's commitment, belief in their quality and scarcity, and the sense of self-esteem from having them,. Consumer interest in these handmade products has shown explosive growth and has been coupled with the recent development of three-dimensional (3D) printing technologies. Etsy.com is the world's largest online handmade platform. It is no different from any other online platform; it provides an online market where buyers and sellers virtually meet to share information and transact business. However, Etsy.com is different in that shops within this platform only deal with handmade products in a variety of categories, ranging from jewelry to toys. Since its establishment in 2005, despite being limited to handmade products, Etsy.com has enjoyed rapid growth in membership, transaction volume, and revenue. Most recently in April 2015, it raised funds through an initial public offering (IPO) of more than 1.8 billion USD, which demonstrates the huge potential of online handmade platforms. After the success of Etsy.com, various types of online handmade platforms such as Handmade at Amazon, ArtFire, DaWanda, and Craft is ART have emerged and are now competing with each other, at the same time, which has increased the size of the market. According to Deloitte's 2015 holiday survey on which types of gifts the respondents plan to buy during the holiday season, about 16% of U.S. consumers chose "homemade or craft items (e.g., Etsy purchase)," which was the same rate as those for the computer game and shoes categories. This indicates that consumer interests in online handmade platforms will continue to rise in the future. However, this high interest in the market for handmade products and their platforms has not yet led to academic research. Most extant studies have only focused on machine-made products and intelligent services for them. This indicates a lack of studies on handmade products and their intelligent services on virtual platforms. Therefore, this study used signaling theory and prior research on the effects of sellers' characteristics on their performance (e.g., total sales and price premiums) in the buyer-seller relationship to identify the key influencing e-Image factors (e.g., reputation, size, information sharing, and length of relationship). Then, their impacts on the performance of shops within the online handmade platform were empirically examined; the dataset was collected from Etsy.com through the application of web harvesting technology. The results from the structural equation modeling revealed that the reputation, size, and information sharing have significant effects on the total sales, while the reputation and length of relationship influence price premiums. This study extended the online platform research into online handmade platform research by identifying key influencing e-Image factors on within-platform shop's total sales and price premiums based on signaling theory and then performed a statistical investigation. These findings are expected to be a stepping stone for future studies on intelligent online handmade services as well as handmade products themselves. Furthermore, the findings of the study provide online handmade platform operators with practical guidelines on how to implement intelligent online handmade services. They should also help shop managers build their marketing strategies in a more specific and effective manner by suggesting key influencing e-Image factors. The results of this study should contribute to the vitalization of intelligent online handmade services by providing clues on how to maximize within-platform shops' total sales and price premiums.

Questions and Answers about the Humidifier Disinfectant Disaster as of February 2017 (가습기살균제 참사의 진행과 교훈(Q&A))

  • Choi, Yeyong
    • Journal of Environmental Health Sciences
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    • v.43 no.1
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    • pp.1-22
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    • 2017
  • 'The worstest environment disaster', 'World's first biocide massacre', 'Home-based Sewol ferry disaster' are all phrases attached to the recent humidifier disinfectant disaster. In the spring of 2011, four of 8 pregnant women including 1 adult man passed away at a university hospital in Seoul due to breathing failure. Epidemiologic investigation conducted by the Korean CDC soon revealed the inhalation of humidifier disinfectant, which had been widely used in Korea during the winter, to be responsible for the disease. As well as lung fibrosis hardening of the lungs, other diseases including asthma, rhinitis, skin disease, liver disease, fetal disease or cancers have been researched for their relation with exposure to the products. By February 9, 2017, 5,342 cases had registered for health problems and 1,131 of them were already dead (20.8% mortality rate). Based on studies by government agencies and a telephone survey of the general population by Seoul National University and civic groups, around 20% of the general public of Korea has used these products. Since the market release of the first product by SK Chemical in 1994, over 7.1 million items from around 20 brands were sold up to 2011. Most of the products were manufactured by well-known large conglomerates such as SK, Lotte, Samsung, Shinsegye, LG, and GS, as well as some European companies including UK-based Reckitt Benckiser and TESCO, the German firm Henkel, the Danish firm KeTox, and an Irish company. Even though this disaster was unveiled in 2011 by the Korean government, the issue of the victims was neglected for over five years. In 2016, an unexpected but intensive investigation by prosecutors found that Reckitt Benckiser manipulated and concealed animal tests for its own brand and brought several university experts and company employees to court. The matter was an intense social issue in Korea from May to June with a surge in media coverage. The prosecutor's investigation and a nationwide boycott campaign organized by victims and environmental groups against Reckitt Benckiser, whose product had been used by more than 70% of victims, led to the producer's official apology and a compensation scheme. A legislative investigation organized after the April 2016 national election revealed the producers' faults and the government's responsibility, but failed to meet expectations. A special law for the victims passed the National Assembly in January 2017 and a punitive system together with a massive environmental epidemiology investigation are expected to be the only solutions for this tragedy. Sciences of medicine, toxicology and environmental health have provided decisive evidence so far, but for the remaining problems the perspectives of social sciences such as sociology and jurisprudence are highly necessary, similar to with the Minamata disease and Wonjin Rayon events. It may not be easy to follow this issue using unfamiliar terminology from medical and chemical science and the long, complicated history of the event. For these reasons the author has attempted to write this article in a question and answer format to render it easier to follow. The 17 questions are: Q1 What is humidifier disinfectant? Q2 What kind of health problems are caused by humidifier disinfectant? Q3 How many victims are there? Q4 What is the analysis of the 1,112 cases of death? Q5 What is the problem with the government's diagnostic criteria and the solution? Q6 Who made what brands? Q7 Has there been a recall? What is still on sale? Q8 Was safety not checked by any producers? Q9 What are the government's responsibilities? Q10 Is it true that these products were sold only in Korea? Q11 Why and how was it unveiled only in 2011 after 17 years of sales? Q12 What delayed the resolution of the victim issue? Q13 What is the background of the prosecutor's investigation in early 2016? Q14 Is it possible to report new victim cases without evidence of product purchase? Q15 What is happening with the victim issue? Q16 How does it compare with the cases of Minamata disease and Wonjin Rayon? Q17 Are there prevention measures and lessons?

Clinical review of Typhoid Fever Patients (장티브스에 관한 임상적 관찰)

  • 최정신
    • Journal of Korean Academy of Nursing
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    • v.6 no.1
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    • pp.60-71
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    • 1976
  • The author reviewed the medical records of 96 typhoid fever patients who were diagnosed, admitted, and treated at Sea grave Memorial Hospital from January 1 , 1973 through August 31, 1975. Diagnosis was determined by clinical observation, aerology and bacteriology, eighty patients were treated medically, the remaining 16 patients required surgical intervention. The following results were obtained: 1) The age distribution of the patients revealed that 33.3% wert between 10 and 19 years old 21.9% were between 20 and 29, and 19.8% were between 30 and 39. The majority of patients were from these more active age groups. Male to female sex ratio was 1.3 : 1 2) Seasonal distribution was observed. Most illness occurred in the summer and autumn month 5. 3) 84. 3%of the patients came from farm families. 4) Duration between onset and admission averaged 16.0 days. The group without compilations was admitted after an average of 15. 1 days; The group with complications was ad-matted after an average of 19.4 days. 5) Methods of treatment before admission were as follows: 10.4% at medical clinics, 61, 5% at pharmacies (antibiotics 47.9%, other. drugs 13.5%), 7.3% by herb medications, 20.8% had no treatment. 6) Main clinical symptoms were as follows: fever 93.8%, headache 47.9%, abdominal pain 47.9%, chills 38.5%, cough 36.5%, general weakness 26.0%, nausea e vomiting 24.0% and generalized pain 21.9%. 7) Temperature of patients on admission: 22.9% were 39f or more, 67.6% were between 37℃ and 38℃, and 9.4% were 37℃ or less. 8) Occurrence of intensional bleeding after onset of disease averaged 9.3 days; perforation occurred at an average of 19. 1 days. 9) Interval between onset of major complication and surgical intervention averaged 2.8 days. 10) Among the 68 patients who underwent the bacteriological test the positive rate was 44.1% (30). The positive ,ales to, each separate culture method were as follows: 20.4% in the blood culture, 40.4% in the stool culture and 6.7% in the urine culture. Among these bacteriological positive patients 15 patients had a negative results or less than 160 titer of vidal reaction. 11) The initial vidal test of the total group showed a counts of 160 titer or more in 60.4% and less than 160 titer in 39.6%, 12) W. B. C. Counts in the uncomplicated group indicated that 32.5% were 6,000/㎣ or less, 47.5% were between 6,000 and 10,000, arid 20.0% were 10,000/㎣ or more. In the complicated group, 37.6% were 6,000/㎣ or less, 25,0% were 6,000-10,000/㎣ and 37.6% were 10,000/㎣ or more. 13) Duration of hospital stay of the patients averaged 6.4 days in the uncomplicated group and 12.7 days in the complicated group. 14) Subdiaphragmatic free air simple X-ray was found in 91.7% of the perforated cases. 15) Duration of antibiotic therapy until an febrile state was attained averaged 4.8 days in the uncomplicated group and 6.5 days in the complicated group. 16) Operative procedures were as follows: one layer simple closure of their perforation with or without debasement in 56.3%, drainage only in 6.3%, small bowel resection with primary anastomosis in 18.8% , externalization in 6.3%, cholecystectomy in 6.3%, The clinical findings of this study suggest the following recommendations. According to Top's report; 1% of typhoid fever patients treated with chlorarnphenicol and 2% of patients treated with other drugs become chronic carriers. Therefore, importance should be given to the strict control of these carriers. Immunization, improvement of sanitation and living standards are all needed for the prevention and treatment of disease, but a more serious problem is a lack of knowledge on the part of patients and their families. Thus it is most urgent to enlighten the citizens about the transmission and hygiene related to contagious disease. Legal restriction of sale of antibiotics at drug stores without a physician's prescription is an urgent matter for public health administrators. An even more important nursing responsibility is the reemphasis on health education both in the clinical setting and in the home.

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Nitrogen Uptake, Yield and Gross Income of Sweet Corn as Affected by Nitrogen (질소시비량이 단옥수수의 질소흡수, 수량 및 조수입에 미치는 영향)

  • 이석순;최상집
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.35 no.1
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    • pp.83-89
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    • 1990
  • A sweet corn hybrid, Golden Cross Bantam 70, was grown at 0, 5, 10, 15 and 20kg/10a of nitrogen (N) under the transparent P. E. film mulch to find the best yield evaluation method. Culm length, ear height, number of tillers increased and silking date was earlier by 1-2 days with increased N level. Leaf area index of main culm at harvest increased with increased N level. Marketable ears were divided into two classes according to the whole sale market price; the frist grade of which husked ear weight over 150g (unhusked ear weight 230g) and the second grade of which husked ear weight between 100 and 150g (unhusked ear weight between 180 and 230g). Average length, thickness, and weight of both grades of marketable ears were not different among the N levels. The proportion of the first grade increased with increased N level. However, total number and weight of marketable ears and gross income per 10a calculated considering weight and number of ears increased with increased N level. There were highly positive correlations between gross income and ear number or ear weight per l0a. The number and weight of marketable ears were underestimated at high N levels compared with gross income. Dry matter yield of stover ranged 740-963kg/10a and increased with increased N level with 20. 8-24.5% dry matter content. Rice black-streaked dwarf virus infection rate was 11.8-15.0%, but it was not related to N level. N concentration in ear was similar but that in stover increased with increased N level. Total N uptake increased but N recovery decreased with increased N level.

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