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Effect of Different PE Mulching Duration on the Competition Ability of Sesame Growing in Association with Various Weed Communities (비닐피복기간(被覆期間)이 잡초군락형성(雜草群落形成)에 참깨의 경합력(競合力)에 미치는 영향(影響))

  • Lee, J.I.;Kang, C.W.;Kwon, Y.W.
    • Korean Journal of Weed Science
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    • v.6 no.1
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    • pp.33-41
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    • 1986
  • This experiment was conducted to determine the influence of weed competition in sesame and the periods for weed control. Competition periods (days), for which sesame was seeded under transparent polyethylene film at May 15, were 10, 15, 30, 45, 60, 75, 90, and full growth season of sesame. Weed control periods (days), for which sesame was seeded under black polyethylene film at June 15, were 10, 15, 30, 45, 60, and full growth season of sesame. Dominant weeds were Ponulaca oleracea, Digitaria sanguinalis, Acalypha australis, L. Cyperus arnuricus, Arenaria aesrphllifolia, Cardamine flexucosa, Mollugo Stricta and Digitaria eschaemum. The number of weeds was maximum at the 30 days after planting. Broad leaf weeds were dominant than grass weeds, and then decreased the total number of weeds by the reason of major decrease of broad leaf weeds. However, the weight of weeds increased continuously. No weeds appeared until the 15 days after planting and the weight of broad leaf weeds was heavier than that of grass weeds until 45 days after planting. However, grass weeds were heavier than broad leaf weeds after 60 days after planting. The hazards of weeds on the growth and development appeared seriously from the 60 to 75 days after planting, but main yield reduction appeared from 30 days after planting. Therefore once more hand weeding should be practiced within 30 days after planting to minimize yield decrease. Serious hazards by weed growing appeared by removing black PE film after 15 to 30 days after planting in growth characteristics and 30 days later in grain yield. Leaf growth showed maximum from 45 to 60 days after planting and then decreased as compared with the continuous increase of stem and root in optimum planting, transparent PE film mulch and hand weeding. Leaf growth didn't show reducing in PE film mulch and weedy check but total weight of weeds increased and growth of sesame decreased as compared to PE film mulch and hand weeding. Leaf, stem and root growth of sesame, and weed weight under black PE film mulch showed same tendancy and lower growth of sesame as compared with optimum planting, transparent PE film mulch. Correlation between sesame yield and weeds weight were r =$ -0.874^{**}$ in the optimum planting and r = $-0.712^{**}$ in the late planting, so that the more weeds increase, the lesser sesame yield.

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A Study on Transition of Rice Culture Practices During Chosun Dynasty Through Old References IX. Intergrated Discussion on Rice (주요(主要) 고농서(古農書)를 통(通)한 조선시대(朝鮮時代)의 도작기술(稻作技術) 전개(展開) 과정(過程) 연구(硏究) - IX. 도작기술(稻作技術)에 대(對)한 종합고찰(綜合考察))

  • Guh, J.O.;Lee, S.K.;Lee, E.W.;Lee, H.S.
    • Korean Journal of Weed Science
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    • v.12 no.1
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    • pp.70-79
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    • 1992
  • From the beginning of the chosun dynasty, an agriculture-first policy was imposed by being written farming books, for instance, Nongsajiksul, matched with real conditions of local agriculture, which provided the grounds of new, intensive farming technologies. This farming book was the collection of good fanning technologies that were experienced in rural farm areas at that time. According to Nongsajiksul, rice culture systems were divided into "Musarmi"(Water-Seeded rice), /"Kunsarmi"(dry-seeded rice), /transplanted rice and mountainous rice (upland rice) culture. The characteristics of these rice cultures with high technologies were based of scientific weeding methods, improved fertilization, and cultivation works using cattle power and manpower tools systematically. Reclamation of coastal swampy and barren land was possible in virtue of fire cultivation farming(火耕) and a weeding tool called "Yoonmok"(輪木). Also, there was an improved hoe to do weeding works as well as thinning and heaping-up of soil at seeding stages of rice. Direct-seeded rice culture in flat paddy fields were expanded by constructing the irrigation reservoirs and ponds, and the valley paddy fields was reclaimed by constructing "Boh(洑)". These were possible due to weed control by irrigation waters, keeping soil fertility by inorganic fertilization during irrigation, and increased productivity of rice fields by supplying good physiological conditions for rice. Also, labor-saving culture of rice was feasible by transplanting but in national-wide, rice should not basically be transplanted because of the restriction of water use. Thus, direct-seeded rice in dry soils was established, in which rice was direct-seeded and grown in dry soils by seedling stages and was grown in flooded fields when rained, as in the book "Nongsajiksul". During the middle of the dynasty(AD 1495-1725), the excellent labor-saving farmings include check-rowing transplanting because of weeding efficiency and availability in rice("Hanjongrok"), and, nurserybed techniques (early transplanting of rice) were emphasized on the basis of rice transplanting ["Nongajibsung"]. The techniques for deep plowing with cattle powers and for putting more fertilizers were to improve the productivity of labor and land, The matters advanced in "Sanlimkyungje" more than in "Nongajibsung" were, development of "drybed of rice nursery stock", like "upland rice nursery" today, transplanting, establishment of "winter barly on drained paddy field, and improvement of labor and land-productivity in rice". This resulted in the community of large-scale farming by changing the pattern of small-farming into the production system of rice management. Woo-hayoung(1741-1812) in his book "Chonilrok" tried to reform from large-scale farmings into intensive farmings, of which as eminent view was to divide the land use into transplanting (paddy) and groove-seeding methods(dry field). Especially as insisted by Seo-yugo ("Sanlimkyungjeji"), the advantages of transplanting were curtailment of weeding labors, good growth of rice because of soil fertility of both nurserybed and paddy field, and newly active growth because rice plants were pulled out and replanted. Of course, there were reestimation of transplanting, limitation of two croppings a year, restriction of "paddy-upland alternation", and a ban for large-scale farming. At that period, Lee-jiyum had written on rice farming technologies in dry upland with consider of the land, water physiology of rice, and convenience for weeding, and it was a creative cropping system to secure the farm income most safely. As a integrated considerations, the followings must be introduced to practice the improved farming methods ; namely, improvement of farming tools, putting more fertilizers, introduction of cultural technologies more rational and efficient, management of labor power, improvement of cropping system to enhance use of irrigation water and land, introduction of new crops and new varieties.

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The Status, Problems and Countermeasure of Direct Rice Seeding in Honam Province - On Weed control - (호남지방(湖南地方) 직파재배(直播栽培)의 현황(現況), 문제점(問題點) 및 대책(對策) - 잡초방제적(雜草防除的) 측면(側面)에서 -)

  • Ryang, Hwan-Seung;Kim, Jong-Seog
    • Korean Journal of Weed Science
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    • v.12 no.3
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    • pp.271-291
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    • 1992
  • This study was conducted to survey the situation of direct rice seeding in Honam province in Korea to investigate problems and seek countermeasure of weed control in direct rice seeding. The total area of direct rice seeding in the south-western part of Korea (Chonbuk, Chonnam, and Chungnam) was 1650.8ha (732.1ha for direct seeding in dry field and 918.7ha for direct seeding in flooding field) in 1992. The followings are summary of the study. 1. In case of direct rice seeding in dry field, butachlor EC and G at 3 to 5 DAS was mostly selected by farmers to control weeds in dry field. Benthiocarb or chlornitrofen was also used in few cases. At 10 to 14 DAS just before rice emergence, tank misture of butachlor EC and paraquat was treated by some farmers. At 35 to 40 days, after flooding mixture of sulfonylurea derivatives was sequentially applied. Surviving weeds including barnyardgrass were finally controlled by mixture of bentazon+quinclorac WP foliage application. 2. In case of direct rice seeding in flooding field, weed control were mostly unsuccessful partially due to wrong selection of herbicide and missing the optimum application time. Three relatively successful weed control in the survey were summarized as follows. 1) Oxadiazon EC, butachlor or benthiocarb were treated just after puddling(5 to 7 days before seeding). then mixture of bentazone+quinclorac WP or sulfonylurea derivatives was sequently applied to control remaining weeds at 20 days after seeding. 2) Mixtures of bensulfuronmethyl+dimepiperate G, pyrazosulfuronethyl+molinate G, or bensulfuronmethyl+mefenacet+dymron G were applied at 11 days after puddling when barnyardgrass were at 2.0 leaf stage. Phytotoxicity was not found in case of mixture of bensulfuronmethyl+dimepiperate G but found in the other two cases but disappeared later. 3) Mixtures of bensulfuronmethyl+quinclorac G., pyrazosulfuronethyl+quinclorac G or betazone and quinclorac G were treated after 18 to 20 days after puddling when barnyardgrass was within 3.0 leaf stage. It showed good weed control in both annuals and perrenials without phytotoxicity. On the contrary, other sulfonylurea derivatives such as middle periodic herbicide showed poor weed control against barnyardgrass, so that sequential treatment of bentazone+quinclorac WP mixture was required. 3. Herbicidal characteristics and optimum application time of 45 rigistered herbicides in Korea were analyzed to discover new substitute for quinclorac mixture, that showed excellent weed control against barnyardgrass at its 3 leaf stage or older. The analysis revealed that 70% of herbicides were for preemergence and the others were post periodic herbicide. Most farmers favor to apply herbicide when rice seedlings completely rooted, at this time barnyardgrass are at 2.5-3.0 leaf stage. Therefore herbicide of which optimum application time had long is required. In this study. 6 middle periodic herbicides among sulfonylurea derivatives and 2 quinclorac mixture were selected and evaluated their weeding spectrums at different leaf stage of barnyardgrass in both soil application in flooding condition and foliage application in dry paddy field. The order of weeding spectrum in magnitude was as follows : bentazone+quinclorac WP> bentazone + quinclorac G>bensulfuronmethyl + quinclorac G>pyrazosulfuronethyl + quinclorac G> pyrazosulfuronethyl + Molinate G>bensulfuronmethyl + mefenacet + dymron G>bensulfuronmethyl + mefenacet G>bensulfuron methyl+benthiocarb G. The above results coincided with that of the survey. In conclusion, there is no proper substitute for quinclorac mixrure, which can control barnyardgrass at 3.0 leaf stage or even older. Therefore quinclorac should be supplied continuously to farmers in order to anchor direct rice seeding in Korea. Author suggested the followings to eastablish direct rice seeding technology effectively and quickly : 1) A tentatively named "The research committee for direct rice seeding" which was composed of farmers. researchers and goberment. should be eastablished to cooperate effectively. 2) Development of a pricise direct rice seeding machine for both dry and flooding paddy field. which is workable regardless of condition and varieties of seeds. 3) Study on protecting rice seed and seedling from sparrows. 4) Systematic studies of weed control techniques in direct rice seeding to standardize herbicide application. 5) Studies on farm-land reformation. techniques of precise land preparation. and direct rice seeding using an airplane.

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Ecological Studies on the Transition of Sheath Blight of Rice in Korea (한국(韓國)에서의 벼 잎집무늬마름병 발생변동(發生變動)에 관(關)한 생태학적(生態學的) 연구(硏究))

  • Yu, Seung-hun
    • Korean Journal of Agricultural Science
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    • v.4 no.2
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    • pp.283-316
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    • 1977
  • In an attempt to obtain a basic information to develop an effective integrated system of controlling sheath blight of rice in Korea, the transition of this disease, the variation of cultural characters and pathogenicity of the pathogen, environmental conditions affecting the disease outbreak and varietal resistance have been investigated. 1. Rice sheath blight which has been minor disease in the past was widely spread, especially since 1971. This disease has promptly spread all over the country and infected 65.2% of total rice growing area in 1976. Various factors are considered to be related to such transition of this disease. Above all, increace of application of nitrogenous fertilizer, early season and earlier cultivation of rice, introduction of more susceptible "Tongil" varieties etc. must be important factors influencing the outbreak of this disease. 2. Great variations in cultural characteristics-such as mycelial growth rate, color of the medium, amount of the aerial mycelium, shape and color of the sclerotia- and in the pathogenicity of isolates of the pathogen, Thanatephorus cucumeris Dank were observed. The optimum temperature for mycelial growth also varied with isolates, from $25^{\circ}C$ to $30^{\circ}C$. There were not necessarily any correlation between curtural characteristics and pathogenicity of isolates of Thanatephorus cucumens. 3. Mycelial grow th of isolates of Thanatephorus cucumens on the PDA medium were correlated with the air temperatures of the region where the isolates were collected. The isolates from the regions with high temperature grew well on PDA medium at $35^{\circ}C$ than those from the region with low temperature, on the other hand, the isolates from the regions with the low temperature grew well on the same medium at $12^{\circ}C$ than those from the regions with high temperature. 4. Pectin polygalacturonase (PG) and cellulase (Cx) were most active on the 3rd day after inoculation on the leaves of rice plant with Thanatephorus cucumeris, whereas pectin methylestrase (PE) was most active on the 4th day after inoculation. Relationship between the activities of PE of isolates and the strength of pathogenicity of isolates was obtained, but PG and cellulase activities were not correlated with pathogenicity of isolates. 5. The tolerence of sclerotia from in-vitro culture to low temperature varied with their water content, the dried cultural sclerotia were more tolerent than wet ones, Dried cultural sclerotia maintained almost 100% germinability for 45 days at $-20^{\circ}C$, whereas wet sclerotia lost viability at $-5^{\circ}C$. The germination ratio of the sclerotia after overwintering changed from 18% to 70% according to the water content of the test paddy fields and the ratio was low in wet paddy condition. 6. To investigate the host range of this fungi in and near paddy field, 17 weeds were inoculated with fungi. The lesions of sheath blight disease was obserbed on Sagittaria trifolia L., Echinochloa crusgalli P. Beauv., Monochoria vaginal is Presl, Polygonum Hydropiper L., Eclipta prostrata L., Digitaria sanguinalis Scapoli. 7. When the level of nitrogen applied was doubled over standard level, total nitrogen content in rice sheath increased, ami when silicate was applied, starch content in rice sheath decreased, inducing the rice plants more susceptible to sheath blight disease. Increased dressing of potash ferilizer reduced the incidence of sheat blight disease. 8. The percentage of infected stems in the early period increased more in the narrow hill plot than in the wide hill plot, but in the late period this tendency was inversed; the percentage of infected stems as well as severity in the wide hill plot increased more compared to the narrow hill plot, and the disease severity in the one plant per hill plot was also low. The number of stems in the wide hill plot was more than the number of stems in the narrow hill plot. This indicates that the microclimate, such as the relative humidity, in the narrow hill plot was more favorable for the development of this disease. 9. There was a high negative correlation between the disease severity of varieties to the sheath blight and the maturity of the varieties, that is, the early varieties were more susceptible than the late ones, and much-tillering varieties usually showed more infection than less tillering varieties. 10. No relationship was obtained between the percentage of infected stems in the early period and the severity after heading, whereas a distinct relationship was obtained between former and latter after Aug. 10.

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A Study on the Job Performance of Dental Coordinators and Their Perception (치과코디네이터의 업무수행 및 인식도에 관한 조사연구)

  • Kwon, Soon-Bok;Kim, Young-Nam;Moon, Hee-Jung;Shin, Myung-Suk;Han, Gyeong-Soon;Han, Su-Jin
    • Journal of dental hygiene science
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    • v.5 no.4
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    • pp.211-220
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    • 2005
  • The purpose of this study was to examine the job performance of dental coordinators and their perception of their job to lay the groundwork for utilizing dental personnels more efficiently. The subjects in this study were dental coordinators who worked at selected dental hospitals and clinics in Seoul, Gyeonggi province and Incheon. A survey was conducted to gather data from May 1 to August 8, 2005 and answer sheets from 108 respondents were analyzed. The findings of the study were as follows: 1. As for the length of service, 43.5 percent of the dental coordinators investigated had worked at dental institutes for five years or more, which was followed by less than two years(19.5%) and three years to less than five years(19.4%). Concerning the length of service as dental coordinators, 39.8 percent had served for less than two years, and 19.4 percent had worked for two years to less than three years and for five years or more respectively. Regarding the name of position, 38 percent were called team leaders, and 30.6 percent were called coordinators. As to duties, the largest group of them that stood at 30.6 percent were in charge of receiving, and in regard to department, the largest group, 57.4 percent, belonged to the treatment backup department. 2. Concerning education, the greatest number of them, 45.4 percent, had received education at private institutes, and 73.1 percent found it necessary for dental coordinators to take an authorized qualification test. 43.5 percent, the largest group, looked upon the central government as the best organization to authorize their qualifications and 70.8 percent believed that what they learned enabled them to perform their job successfully. As to the necessity of follow-up education as a means to improve job performance, 96.3 percent consented to it. As for the reason, 63.9 percent considered that necessary to enhance their own ability and 22.2 percent were in want of systematic education. Regarding educational expenses, 29.6 percent were subsidized by the dental institutes where they had worked and 25.9 percent had totally been responsible for that. Regarding a required course, medical service and marketing was most widely pointed out(66.7%), followed by theory and practice(65.7%) and introduction to dentistry(57.4%). As to what sort of education they wanted to receive more, dental service and marketing was selected the most, followed by practical health insurance(35.2%). 3. In regard to what type of job they performed as dental coordinators, 88.9 percent were in charge of appointment in the field of customer service, and 87.9 percent paid attention to having good manners as service providers in the area of self-management. In the field of hospital affairs, 81.3 percent were in charge of receiving. 4. As to their awareness of dental coordinator job, the largest group took pride in the job they performed ($3.99{\pm}0.76$), and the second largest group believed that dental coordinators made a great contribution to hospital management ($3.92{\pm}0.70$). The third largest group gave a great weight to their own job ($3.91{\pm}0.84$) in light of overall dental duties and the fourth largest group found themselves to get along with other employees regardless of position ($3.86{\pm}0.74$). The fifth largest group believed their job was of great use for promoting the oral health of patients ($3.76{\pm}0.75$), and the sixth largest group thought the future of dental coordinators was promising($3.74{\pm}0.86$). 5. In regard to their perception by age group, those who were older had a better opinion on every item of their job in general. Their age made a statistically significant difference to their view of the weight of dental coordinator job(P < 0.001) in light of overall dental duties, of being approved and trusted by managers(P < 0.01), of social awareness of dental coordinator, and of being understood and approved by other employees and dentists. Their pride in current job and their satisfaction with the name of their position were statistically significantly different according to their age as well. Besides, their age made a statistically significant difference to their opinion about whether or not there was an age limit to their occupation and about their contribution to hospital management (P < 0.05). 6. As for their perception by type of job, the dental hygienists were generally most satisfied with their job, followed by nursing aids and others. There was a statistically significant gap among their opinions about whether to make a job-related decision on their own(P < 0.001). the weight of their job in terms of overall dental duties, whether their job improved their ability, whether their job made a great contribution to enhancing the oral health of patients, whether their job was understood and approved by other employees(P < 0.01), social awareness of their job, whether they conflicted with other employees during job performance, and whether dental hospitals or clinics offered a self-development opportunity for them to take their ability to another level(P < 0.05). And their satisfaction with current pay was statistically significantly different as well.

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Studies on the Propagation of the Freshwater Prawn, Macrobrachium nipponense (De Haan) Reared in the Laboratory 2. Life History and Seedling Production (담수산 새우, Macrobrachium nipponense (De Haan)의 증${\cdot}$양식에 관한 생물학적 기초연구 2. 생활사 및 종묘생산에 관한 연구)

  • KWON Chin-Soo;LEE Bok-Kyu
    • Journal of Aquaculture
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    • v.5 no.1
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    • pp.29-67
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    • 1992
  • Life cycle and seed production of the freshwater prawn, Macrobrachium nipponense, were studied and the results are as follows : 1. Larval development : Embryos hatched out as zoea larvae of 2.06 mm in mean body length. The larvae passed through 9 zoea stages in $15{\~}20$ days and then metamorphosed into postlarvae measuring 5.68 mm in mean body length. Each zoea stage can be identified based on the shapes of the first and second antennae, exo- and endopodites of the first and second pereiopods, telson and maxillae. 2. Environmental requirements of zoea larvae : Zoea larvae grew healthy when fed with Artemia nauplii. Metamorphosing rate was $65{\~}72{\%}$ at $26{\~}28\%$ and $7.85{\~}8.28\%_{\circ}Cl.$. The relationship between the zoeal period (Y in days) and water temperature (X in $^{\circ}C$) is expressed as Y=46.0900-0.9673X. Zoeas showed best survival in a water temperature range of $26{\~}32^{\circ}C$ (optimum temperature $28^{\circ}C$), at which the metamorphosing rate into postlarvae was $54{\~}72\%$ The zoeas survived more successfully in chlorinity range of $4.12{\~}14.08{\%_{\circ}}Cl.$, (optimum chlorinity $7.6{\~}11.6\;{\%_{\circ}}Cl.$.), at which the metamorphosing rate was $42{\~}76{\%}$. The whole zoeal stages tended to be longer in proportion as the chlorinity deviated from the optimum range and particularly toward high chlorinity. Zoeas at all stages could not tolerate in the freshwater. 3. Environmental requirements of postlarvae and juveniles : Postlarvae showed normal growth at water temperatures between $24{\~}32^{\circ}C$ (optimun temperature $26{\~}28^{\circ}$. The survival rate up to the juvenile stage was $41{\~}63{\%}$. Water temperatures below $24^{\circ}C$ and above $32^{\circ}$ resulted in lower growth, and postlarvae scarcely grew at below $17^{\circ}C$. Cannibalism tended to occur more frequently under optimum range of temperatures. The range of chlorinity for normal growth of postlarvae and juveniles was from 0.00 (freshwater) to $11.24{\%_{\circ}}Cl.$, at which the survival rate was $32{\~}35\%$. The postlarvae grew more successfully in low chlorinities, and the best growth was found at $0.00\~2.21{\%_{\circ}}Cl.$. The postlarvae and juveniles showed better growth in freshwater but did not survive in normal sea water. 4. Feeding effect of diet on zoea Ilarvae : Zoea larvae were successfully survived and metamorposed into postlarvae when fed commercial artificial plankton, rotifers, and Artemia nauplii in the aquaria. However, the zoea larvae that were fed Artemia nauplii and reared in Chlorella mixed green water showed better results. The rate of metamorphosis was $68\~{\%}75$. The larvae fed cow live powder, egg powder, and Chlorella alone did not survive. 5. Diets of postlarvae, juveniles and adults : Artemia nauplii and/or copepods were good food for postlarvae. Juveniles and adults were successfully fed fish or shellfish flesh, annelids, corn grain, pelleted feed along with viscera of domestic animals or fruits. 6. Growth of postlarvae, juveniles and adults : Under favorable conditions, postlarvae molted every five or six days and attained to the juvenile stage within two months and they reached 1.78 cm in body length and 0.17 g in body weight. The juveniles grew to 3.52 cm in body length and 1.07 g in body weight in about four months. Their sexes became determinable based on the appearance of male's rudimental processes (a secondary sex character) on the endopodites of second pereiopods of males. The males commonly reached sexual maturity in seven months after attaining the postlarvae stage and they grew to 5.65 cm in body length and 3.41 g in body weight. Whereas the females attained sexual maturity within six to seven months, when they measured 4.93 cm in body length and 2.43 g in body weight. Nine or ten months after hatching, the males grew $6.62{\~}7.14$ cm in body length and $6.68{\~}8.36$ g in body weight, while females became $5.58{\~}6.08$ cm and $4.04{\~}5.54$ g. 7. Stocking density : The maximum stocking density in aquaria for successful survival and growth was $60{\~}100$ individuals/$\ell$ for zoeas in 30-days rearing (survival rate to postlarvae, $73{\~}80{\%}$) ; $100{\~}300$ individuals/$m^2$ for postlarvae of 0.57 cm in body length (survival rate for 120 days, $78{\~}85{\%}$) ; $40{\~}60$ individuals/$m^2$ for juveniles of 2.72 cm in body length (survival rate for 120 days, $63{\~}90{\%}$) : $20{\~}40$ individuals/$m^2$ for young prawns of 5.2 cm in body length (survival rate for 120 days, $62\~90{\%}$) ; and $10\~30$ individuals/$m^2$ for adults of 6.1 cm in body length (survival rate for 60 days, $73\~100{\%}$). The stocking density of juveniles, youngs and adults could be increased up to twice by providing shelters.

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A Study of the Attitude of/and Problems Encountered by Senjor Home Economist Toward the Integration of Family Planning Education in the Korean Formal School System (가정학교육 영역에서의 인구교육문제에 관한 조사연구 -선임가정학자들을 대상으로-)

  • 김지화
    • Journal of the Korean Home Economics Association
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    • v.19 no.3
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    • pp.83-101
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    • 1981
  • Under the full consideration of the growing need and importance of population education in the field of home economics in Korea, the study was carried out to verify and assess the following facts on the current issues of population education of home economists who are presently engaging in teaching professions as the teachers of middle and high school and professors of college and universities by setting its primary objectives of the study as followings; 1) to assess the degree of general knowledge and attitudes of home economists toward population education in the field of home economics, 2) to verify the problems encountered in implementing population education by home economists in its field, 3) to find an existing status of previous trainings received and other activities of population education of home economists aimed at utilizing these findings as a part of reference materials when the population education is conducted in the field of home economics. In order to attain these objectives described above, the questionnaire was carefully designed to house a total of 40 questions with good combination of multiple-choice and the simple answer questions. The mail questionnaire survey was conducted by establishing teachers of home economics at middle/high schools and college/universities as Senior Home Economists(SHE) who are from public, private liberal arts and vocational schools. The rate of response observed during the survey was 45.6 percent and the findings of the survey research are as follows: 1) Examining the status of the respondents by residence and religion, it was found that 45 percent of middle & high school teachers ar.d 59. 1 percent of college professors are residing in Seoul city area and that the largest percent of them are christian in their religion. Analyzing respondents by their ages, 56 percent of middle/high school teachers are in their 30s, 45 percent of college professors are in their 40s, and 37 percent of college teachers are in their 30s. In addition, 13 percent of the total respondents are found to be unmarried. The study also revealed that 71 percent of the college professors finished Master Degree course and 82 percent of middle/high school teachers are graduated from college level lasting 4 years. Looking over the status cf major fields of respondents, 68.4 percent of middle/high school teachers are specialized in home economic education and the college professors, on the other hand, show relatively even prortion by specializing in the order of food & nutrition science, clothes & textile science and home managerial science. As far as the length of teaching experience is concerned, a relatively longer period of teaching experience is observed in the college professors in comparison with that of middle/high school teachers. In other words, 33.3 percent of middle/high school teachers are experienced in teaching from 6 to 10 years on average while 43.9 percent of college professors show more than 16 years of experience. 2) Examining the status of existing number of children cf the respondents, one boy and one daughter pattern is predominant, showing 28.5 percent in middle/high school teachers and 21.1 percent in college professors. As for the desired number of children of unmarried respondents, it is observed that 43.8 percent of middle/high school teachers desire to have one boy and one girl, and 31.3 percent of college professors want to have one child regardless of the sex. By assessing the degree of awareness of the population education through their students, it is observed that 53 percent of middle/high school teachers and 50 percent of college professors are aware of population education in some extent and that a majority of respondents took the positive attitudes toward an inclusion of family planning components into the formal school education. Another noteworthy to observe is that a total of 84.8 percent out of middle/high school teachers pointed that the population education currently conducted at schools as a part of home economics are less sufficient than it should be. 3) Analyzing the tendency as to whether the respondents were experienced in receiving population education during the time when they were students, 75 percent of college professors and 59 percent of middle/high school teachers responded negative answers in the survey. In the mean time, a total of 50 percent of the respondents replied that they began to acknowledge the importance of population education mainly through the participation of some sort of population-education orientend seminars, experienced by 40 percent of college professors and 80 percent of middle/high school teachers. 4) What it calls attention in this study was to find that 96.5 percent of middle/high school teachers and 72 percent of college professors conduct population education to some extent during their lecture hours and that more than 80 percent of them are never experienced in teaching population and family planning contents in their regular classes. It is, on the other hand, found that no more than once was the response of those who believe themselves that they are experienced in teaching these relevant components to their students. Analyzing the contents of the subjects being taught in the class, a large percent of them are found to be consisted of population and family planning contents. According to this study, the current population education through the formal school is quite inactive. Analyzing the facts, 44.9 percent of the college professors responded that the population and family planning components are quite apart from their specialization which eventually generates lack of interest in the field. 5) It is also noticed through the study that the degree of frequency of commenting on population and family planning contents during the classes was depending significantly on their specializations which means that the degree of frequency varies from a major to another. Those who majored in home managerial science was the first one, as compared to others who majored in different specializations. Glancing over the status of correlations between ages of the respondents and numbers of seminar paticipation, it is quite clear that the aged group participated more than the younger group did, and that the most highest number of participations made by college professors were those who are in 50s. In addition, it is also found that those who are aged 20s and 60s of the respondents were the group who comments least on the contents of population and family planning at their classes. The suggestions and recommendation made through this survey research are as follows. 1) No one denies that the rapid increase of population, as compared to the limited size of land and resources, will certainly affect adversly to an enhancement of individual life quality which will, eventually, bring forth the poverty of the nation. This is the reasson why we are insisting that the world population be controlled up to an optimum level with a matter of global concerns. It is our understading that the primary aim for reducing number of population is believed to be attained only by conducting the systematic and comprehensive population education through the formal schools. Therefore, the role of home economists in the field of population/family planning education is considered very importment due to the fact that an ultimate goal of population education is placed in elevating the quality of family life by having optimum number of children through family planning program. 2) It is quite clear that home economists as teachers of formal school in all level are invited to pay their attention on redefining the ultimate goal of education and that of population education. We also understant that the primary objective of population education is to change the norm and value of the clients by replenishing the students with pertinent knowledge and attitudes on population and its related problems through a sort of education in order to attain the ultimate goal for enhancing the quality of life. There is no exception in the theory of home economics. An altimate goal of home economics is to elevate the general quality of life through an establishment of value existed in daily life. Considering the relations between population education and home economics, it is quite indespensable to bandle population components as an integral part in the field of home economics. We believe, therefore, that the senior home economists positive participation in the effort population control is more needed than it has been. 3) It is also strongly urged that population education should be a part of instructor training course for home economics. In other words, the teacher of home economics should be well aware of population and its problems by teaching interrelationship between population education and home economics, needs, contents and methods of population education during the instructor training courese for home economics. In addition, the senior home economists should be encouraged through positive participation on the short term training by types of domestic and international seminar, workshop, etc. 4) We certainly believe that the population education can not sustain itself without any backing-up of information and findings' of various and comprehensive researches of natural and social sciences. Accordingly, every senior home economist is invited to exert their maximum effort to conduct systematic study with an aim to utilize these findings and information at best in population education in the field of home economics. Therefore, we consider that the development of training material is imminent in order to provide effective and efficient population education through the for training of home economies. It should be noted that these training materials must be carefully designed, tailored and developed to meet the different classes of trainees under the considerations as to whether it is easily adaptable and infusable into the curricula of every field of home economics, and it is acceptable in the degree of difficulty and quality in its contents. 5) It is true that there are many domestic and international research rapers, reports and findings in the field of population education and family planning. However, there is a tendency that the most of research papers are heavily relying on the authors intension and preferences in its expression and publication. Under these circumstances, it is urged that the home economists should aware of the growing need of the technical training in order to keep these available information and research findings reprocessed and redesigned to insure the practical application into the population education in the field of home economics in Korea.

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Variation of Genus Ilex in Korea and their Ornamental Values (Ilex속(屬) 수목(樹木)의 유전변이(遺傳變異)의 분석(分析)과 조경학적(造景學的) 이용가치(利用價値)의 조사(調査) 연구(硏究))

  • Yim, Kyong Bin
    • Journal of Korean Society of Forest Science
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    • v.42 no.1
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    • pp.1-38
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    • 1979
  • The woody species of Genus Ilex which are endemic to Korea are distributed on limited area due to solely temperature factor. There is some differences according to species, however in general, the evergreen Ilex are found along southern coastal area of Korean Peninsula and near islands where the cold index does not exceed $-5^{\circ}C$. But Ilex macropoda and the variety, only deciduous ones, are grown in temperate zone of the peninsula and some islands. The list of Ilex species of Korea are as follows. Ilex cornuta Lindley et Pax., I. crenata Thunb. var. microphylla Max., I. crenata Thunb., I. rotunda Thunb., I. macropoda Miq., I. macropoda Miq. var. pseudo-macropoda Loensner, I. integra Thunb. The author surveyed the populations of Ilex species as many as possible and data of some characters such as leaf shape, spine, fruit shape, stomata density, sex ratio in natural communities, etc. are collected. Almost all the Ilex species in Korea show sporadic distribution. This means quite small sized populations isolate distantly each other eliminating the change of gene exchange in between. Particularly Ilex conuta and I. crenata show the morphological differentiation among populations as well as significant individual variation within a population. These were true with such characteristics, leaf shape, leaf dimension, leaf margin, fruit shape, spine, and stomata density. The founded are that the fruit length and the stomata density counted on the beneath surface of leaves of Ilex cornuta increased with the decrease of latitude. These are naturally closely related with the cold index values. The table shown below indicates the correlation between mean stomata density per $0.3642mm^2$ and cold index values. These relation however were not observed on Ilex crenata. The most dominated natured in relation to individual variation were outline of leaf, the number of marginal spine, the shape of leaf cross section and the degree of luster of the upper leaf surface. As shown in photos 5~7, these variations are agreed at a glance. There are reports that the development of marginal spines in some Ilex species is associated with the juvenility and topophysis. In present study, these two factors were neglected because of the intended sampling procedure. Of Ilex rotunda, population difference with the characteristics of leaf length is recognized but not for leaf width, petiole length, and fruit size. However, individual variations within a population were significantly large. In case of Ilex integra, only individual differences within population were calculated statistically for such characteristics as leaf length, leaf width, and petiole length. As to natural population, the sex ratio was 1:2 (female to male) for Ilex cornuta, and 1:1 for Ilex crenata. The tendency of more male than female in I. cornuta was agreed to other observations. Preparing the tip cutting of length 10cm, and treating with IBA, then attaching earth ball to the cut end, very successful rooting percentages were obtained. Asexual propagation has the advantages of maintaining the heterozygosity of existing varieties and overcoming the difficulties of delayed seed germination frequently encountered with Ilex species. Considering a great deal of variation in morphological traits, a good possibility of selection breeding for decorative and ornamental purposes exists. At present, these evergreen Ilex are ignored by local people as nuisance weedy shrubs. So the proper protection measures should promptly be taken.

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The Clinical Characteristics of Lung Cancer in Patients with Idiopathic Pulmonary Fibrosis (특발성 폐섬유화증에 동반된 폐암 환자의 임상적 특정)

  • Park, Joo-Hun;Lee, Jin-Seong;Song, Koun-Sik;Shim, Tae-Sun;Lim, Chae-Man;Koh, Youn-Suck;Lee, Sang-Do;Kim, Woo-Sung;Kim, Won-Dong;Kim, Dong-Soon
    • Tuberculosis and Respiratory Diseases
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    • v.46 no.5
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    • pp.674-684
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    • 1999
  • Background : It has been generally known that the incidence of lung cancer is higher in the patients with idopathic pumonary fibrosis (IPF) than those in general population. The reported incidence was variable from 4.8 to 43.2%. There were controversies on the most frequent cell type (squamous cell carcinoma vs. adenocarcinoma) and no study was done about the real concordance of cancer and the fibrotic lesion. And the pulmonary fibrosis may influence not only the development of cancer but also the treatment and prognosis of the cancer, but there was no report on that point. Method : Total 63 patients ($66.8{\pm}7.8$ year, M : F=61 : 2) were diagnosed as IPF combined with lung cancer (IFF-CA) at Asan Medical Center. A retrospective analysis was done about the risk factors of the lung cancer, pulmonary function test, the site of cancer(especially the relationship of the cancer with the fibrotic lesion), the histologic types, and the stage of cancer. The histologic types were compared with those of 2,660 patients with lung cancer who were diagnosed at the same institute for the same period. The effect of IPF on the treatment of the cancer was evaluated with the survival time after the detection of lung cancer. Results : The lung cancer was found in 63(22.9%) out of 281 patients with IPF. But in most of them(45 patients), lung cancer was detected at the same time with IPF and only in 18 patients, the cancer was diagnosed during the follow-up($25.2{\pm}17.7$ months) of IPF. So in our study, 6.7% of patients with IPF developed lung cancer during the course of the disease. The age ($66.8{\pm}7.84$ vs. $63.4{\pm}11.1$ years), percentage of smoker (88.9 vs. 67.2%), and the male gender (96.8 vs. 67.6%) were significantly higher in IPF-CA compared with lone IPF (p<0.05). The odds ratio of smoking was 4.7 compared with non smoking IPF controls. The lung cancer was located more frequently in the upper lobe and 55.5% was in the periphery of lung. The cancer was developed in the fibrotic lesion in 23 patients (35.9%), and in the majority of the patients, the cancer was separated from the fibrosis. The cell type of the lung cancer in IPF-CA was squamous cell carcinoma 34.9%, adenocarcinoma 30.2%, small cell carcinoma 19.0%, large cell undifferenciated carcinoma 6.3%, and others 9.5%. No significant difference in the distribution of histologic type of the lung cancer was found between IPF-CA and lone lung cancer. There was no significant difference in demographic features, cell types, location and the stage of the cancer between the group with concurrent IPF-CA and the group with cancer diagnosed during the follow up of IPF. There was a tendency (but statistically not significant : p=0.081) of higher incidence of adenocarcinoma among the cancers developed in the fibrotic area(43.5%) (F-CA) than in the cancers in non-fibrotic area (22.5%) (NF-CA). The prognosis of the patients with F-CA was poor (median survival : 4 months) compared with the patients with NF-CA (7 months, p=0.013), partly because the prevalence of severe IPF (the extent of fibrosis in HRCT 50%) was higher in F-CA group. Conclusion : These data suggest that the lung cancer in the patients with IPF has similar features to the ordinary lung cancer.

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The Impacts of Social Support and Psychological Factors on Guild Members' Flow and Loyalty in MMORPG (MMORPG에서 길드 구성원들의 사회적 지지와 심리적 요인들이 플로우 및 충성도에 미치는 영향)

  • Kang, Ju-Seon;Ko, Yoon-Jung;Ko, Il-Sang
    • Asia pacific journal of information systems
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    • v.19 no.3
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    • pp.69-98
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    • 2009
  • We investigated what factors motivate gamers to participate in a guild and why they continue to be engaged as members of the guild. We find that, based on the result of focus group interviews with MMORPG gamers, social support and self-esteem factors play important roles. Considering both prior research and the focus group interviews we have conducted, we define social support and character control as independent variables. Character identity, guild identity, and self-esteem are proposed as mediating variables while guild flow and game loyalty as dependent variables. Accordingly, we develop the research model and hypotheses, and verify them empirically. Based on our experiences of playing the WoW game, we proposed a research model and conducted focus-group interviews (FGIs). FGIs involve formulating a hypothesis and then collecting some relevant data. FGIs were conducted face-to-face with students of C University in Korea. We formulated structured interview schedules, and the questions were based on our research variables and personal experiences. The questions for the interviews encompassed the following areas: (a) the demographic characteristics of the focus group; (b) the number of years for which respondents had played online games; (c) the motive for starting a game; (d) the number of game-characters assumed by each gamer; (e) the type of game played; and (f) other issues such as the reasons for involvement in the play, the willingness to reuse the game in case new versions were released, etc. On average, it took two hours to interview each of three groups. A primary set of FGIs was conducted with three groups on the premise that there would be some differences caused by character race (Horde vs. Alliance) or by playable server (Normal vs. Combat). With respect to the manner of playing, we found that guild members shared information, felt a sense of belonging, and played computer games for quite a long time through the guild; however, they did not undergo these experiences when playing alone. Gamers who belonged to a specific guild helped other players without expecting compensation for that, freely shared information about the game, gave away items for free, and more generous with other members who made mistakes. The guild members were aware of the existence other members and experienced a sense of belonging through interactions with, and evaluations from, other players. It was clear that social support was shown within the guild and that it played an important role as a major research variable. Based on the results of the first FGIs, a second set of in-depth FGIs was carried out with a focus on the psychology of the individual within the guild and the social community of the guild. The second set of FGIs also focused on the guild's offline meetings. Gamers, over all, recognize the necessity of joining a community, not only off-line but also online world of the guild. They admit that the guild is important for them to easily and conveniently enjoy playing online computer games. The active behavior and positive attitudes of existing guild members can motivate new members of the guild to adapt themselves to the guild environment. They then adopt the same behaviors and attitudes of established guild members. In this manner, the new members of the guild strengthen the bonds with other gamers while feeling a sense of belonging, and developing social identity, thereby. It was discovered that the interaction among guild members and the social support encouraged new gamers to quickly develop a sense of social identity and increase their self-esteem. The guild seemed to play the role of socializing gamers. Sometimes, even in the real world, the guild members helped one another; therefore, the features of the guild also spilled over to the offline environment. We intend to use self-esteem, which was found through the second set of FGIs, as an important research variable. To collect data, an online survey was designed with a questionnaire to be completed by WoW gamers, who belong to a guild. The survey was registered on the best three domestic game-sites: 'WoW playforum,' 'WoW gamemeca,' and 'Wow invent.' The selected items to be measured in the questionnaire were decided based on prior research and data from FGIs. To verify the content of the questionnaire, we carried out a pilot test with the same participants to point out ambiguous questions as a way to ensure maximum accuracy of the survey result. A total of 244 responses were analyzed from the 250 completed questionnaires. The SEM analysis was used to test goodness-of-fit of the model. As a result, we found important results as follows: First, according to the statistics, social support had statistically significant impacts on character control, character identity, guild identity and self-esteem. Second, character control had significant effects on character identity, guild identity and self-esteem. Third, character identity shows its clear impact on self-esteem and game loyalty. Fourth, guild identity affected self-esteem, guild flow and game loyalty. Fifth, self-esteem had a positive influence on the guild flow. These days, the number of virtual community is rising along with its significance largely because of the nature of the online games. Accordingly, this study is designed to clarify the psychological relationship between gamers within the guild that has been generally established by gamers to play online games together. This study focuses on the relationships in which social support influences guild flow or game loyalty through character control, character identity, guild identity, and self-esteem, which are present within a guild in the MMORPG game environment. The study results are as follows. First, the effects of social support on character control, character identity, guild identity and self-esteem are proven to be statistically significant. It was found that character control improves character identity, guild identity and self-esteem. Among the seven variables, social support, which is derived from FGIs, plays an important role in this study. With the active support of other guild members, gamers can improve their ability to develop good characters and to control them. Second, character identity has a positive effect on self-esteem and game loyalty, while guild identity has a significant effect on self-esteem, guild flow and game loyalty. Self-esteem affects guild flow. It was found that the higher the character and guild identities become, the greater the self-esteem is established. Contrary to the findings of prior research, our study results indicate that the relationship between character identity and guild flow is not significant. Rather, it was found that character identity directly affects game players' loyalty. Even though the character identity had no direct effect on increasing guild flow, it has indirectly affected guild flow through self-esteem. The significant relationship between self-esteem and guild flow indicates that gamers achieve flow, i.e., a feeling of pleasure and excitement through social support. Several important implications of this study should be noted. First, both qualitative and quantitative methods were used to conduct this study. Through FGIs, it was observed that both social support and self-esteem are important variables. Second, because guilds had been rarely studied, this research is expected to play an important role in the online community. Third, according to the result, six hypotheses (H1, H5, H6, H7, H8, and H11) setup based on FGIs, were statistically significant; thus, we can suggest the corresponding relationships among the variables as a guideline for follow-up research. Our research is significant as it has following implications: first, the social support of the guild members is important when establishing character control, character identity, guildidentity and self-esteem. It is also a major variable that affects guild flow and game loyalty. Second, character control when improved by social support shows notable influence on the development of character identity, guild identity and self-esteem. Third, character identity and guild identity are major factors to help establish gamers' own self-esteem. Fourth, character identity affects guild flow through self-esteem and game loyalty. The gamers usually express themselves through characters; the higher character identity is, the more loyalty a gamer has. Fifth, guild identity, established within the guild, has clear effects on self-esteem, guild flow and game loyalty. Sixth, qualitative and quantitative methods are employed to conduct this study. Based on the results of focus group interviews and SEM analysis, we find that the social support by guild members and psychological factors are significant in strengthening the flow of guild and loyalty to the game. As such, game developers should provide some extra functions for guild community, through which gamers can play online games in collaboration with one another. Also, we suggest that positive self-esteem which is built up through social support can help gamers achieve higher level of flow and satisfaction, which will consequently contribute to minimizing the possibility for the players to develop negative attitude toward the guild they belong to.