• Title/Summary/Keyword: life history

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Evolution of Social Life in Wood-Eating Cockroaches (Cryptocercus spp.) : Effects of the Winter Climate on the Evolution of Subsociality

  • Park, Yung-Chul;Choe, Jae-Chun
    • Journal of Ecology and Environment
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    • v.31 no.2
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    • pp.97-105
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    • 2008
  • Subsocial behavior of the genus Cryptocercus cockroaches has been believed as primitive traits of termite eusociality. Thus, it has been believed that understanding Cryptocercus subsociality is a pre-requisite stage to infer evolutionary route of the eusociality in termites. Woodroaches of Cryptocercus are also well known because of its peculiar characteristics including adults living monogamously in pairs, semelparous reproduction, xylophagy, obligatory association between adults and their offspring, slow development, and anal trophallaxis by adults. Based on the previously accumulated data, we try to understand two major components of Cryptocercus life history, development and reproduction. We hypothesize that harsh winter and length of winter might be one of the main causes driving the appearance of the delayed development and semelparous reproduction in Cryptocercus life history.

Biology of Platydema nigroaeneum Motschulsky (Coleoptera: Tenebrionidae) from Korea: Life History and Fungal Hosts

  • Jung, Boo-Hee;Kim, Jin-Ill
    • Journal of Ecology and Environment
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    • v.31 no.3
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    • pp.249-253
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    • 2008
  • We conducted field and laboratory observations of the life histories and fungal hosts of the darkling beetle, Platydema nigroaeneum Motschulsky. P. nigroaeneum, a fungivorous tenebrionid beetle, was a widespread inhabitant of fungi on deciduous trees (Quercus, Salix, Alnus and Carpinus etc.) in Korea. Development from egg to adulthood took $4\sim11$ months in nature and about 66 days in the laboratory at $25.5{\sim}26.1^{\circ}C$ and $63.5\sim64.5%$ relative humidity. Both larvae and adults overwintered in their host fungi or beneath the bark of the host tree near the host fungi. Sporophores of Coriolus $Qu{\acute{e}}let$, Bjerkandera Karst., Daedaleopsis Schroet. and Merulius were common feeding and breeding sites in Korea.

Evolution under unpredictable environmental conditions: quantitative genetics of larval life-history traits in a myobatrachid frog Crinia georgiana

  • Smith, Michael J.;Jang, Yikweon
    • Animal cells and systems
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    • v.16 no.5
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    • pp.425-430
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    • 2012
  • The southwestern Australian frog Crinia georgiana (Anura; Myobatrachidae) inhabits ephemeral pools in which the tadpoles often face desiccation. Under these conditions selection on tadpoles can be severe and can directly affect fitness during the aquatic as well as the terrestrial developmental stages. A quantitative genetic study using a half-sib breeding design was conducted to understand the genetic effects on larval life-history traits. We found no significant additive genetic variance in any of larval traits. Except for hatching period, heritability estimates based on females were high in egg size, larval period, snout-vent length, and weight at metamorphosis, suggesting non-additive genetic effects. These results indicate that any response to selection during hatching and larval periods should be predominately governed by non-additive genetic effects in C. georgiana.

Analysis of a Dynamic Rig Test Model for Truck Chassis Systems (트럭 샤시 시스템의 동적 리그시험모텔 해석)

  • 임재혁;성현수;임세영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.4
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    • pp.94-100
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    • 2004
  • A dynamic finite element analysis of a rig test model for truck chassis systems is conducted to establish an appropriate model designed to predict the fatigue life. A reference Belgian road input, which has been obtained from a field test, is imposed on the finite element model in the modal finite element analysis, and the resulting strain history is employed for the prediction of the fatigue life. This is compared with the prediction based upon the strain history measured in the field test. The two agree with each other within the limitation of the field data and the input data to the model. The high frequency responses over 50 Hz are confirmed to be negligible as far as their effect on the fatigue life is concerned.

A Study on the Prediction of the Fatigue Life of a Lug through the Finite Element Analysis (FEA를 이용한 Lug의 피로 수명 평가에 관한 연구)

  • 이원석;이현우
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.10
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    • pp.88-95
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    • 1998
  • The purpose of this study is to predict the life of a Lug under the real service load history. The techniques of predicting a fatigue life under load spectrum are discussed and some are developed. The stress is calculated by multiplying the stress under unit force with the Finite Element Analysis. The cycles are counted by the Rainflow counting method and then the mean stress effect is considered by the suggested conversion function. The Manson's Double Linear Damage Rule is used as the cummulative damage method.

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Development of Convenient Software for Online Shelf-life Decisions for Korean Prepared Side Dishes Based on Microbial Spoilage

  • Seo, Il;An, Duck-Soon;Lee, Dong-Sun
    • Food Science and Biotechnology
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    • v.18 no.5
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    • pp.1243-1252
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    • 2009
  • User-friendly software was developed to determine the shelf-life of perishable Korean seasoned side dishes in real time based on growth models of spoilage and pathogenic microorganisms. In the program algorithm, the primary spoilage and fastest-growing pathogenic organisms are selected according to the product characteristics, and their growth is simulated based on the previously monitored or recorded temperature history. To predict the growth of spoilage organisms with confidence limits, kinetic models for aerobic bacteria or molds/yeasts from published works are used. Growth models of pathogenic bacteria were obtained from the literature or derived with regression of their growth rate data estimated from established software packages. These models are also used to check whether the risk of pathogenic bacterial growth exceeds that of food spoilage organisms. Many example simulations showed that the shelf-lives of the examined foods are predominantly limited by the growth of spoilage organism rather than by pathogenic bacterial growth.

Euler: Reflections on his Life, Works, and Thoughts (오일러의 삶, 업적, 그리고 사상)

  • Park, Chang-Kyun
    • Journal for History of Mathematics
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    • v.20 no.2
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    • pp.19-32
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    • 2007
  • This Paper aims to introduce Euler's life, works and thoughts, to show that it is his Christian worldview that enables his achievements. His life teaches us the lesson that examining philosophical base and historical background is crucial to understand mathematics or mathematicians, and that it is necessary to overcome given conditions and environments rather than expect better environments to reach meaningful achievements.

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The Formation of Jang Gyung Ak's Medical Concept - Focusing JunChoongrok - (장경악(張景岳) 의학사상(醫學思想)의 형성(形成) - 전충록(傳忠錄)을 중심(中心)으로 -)

  • Oh, Joong Wan;Kim, Nam il
    • The Journal of Korean Medical History
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    • v.15 no.1
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    • pp.183-198
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    • 2002
  • Jang Gyung Ak thought the Yang Gi was the basis of life. This is why he said doctors should emphasize on preserving Yang Gi. Before his emphasis on Yang Gi he had to study and criticize the medical concept of HaGan, DanGye and DongWon. By criticizing and overcoming their medical concept's fallacy and limitations, he made his own medicine. JangGyungAk found the importance of YangGi in the theory of changes. In the "the Book of Changes" it is said the rising movement of YangGi is expressed by recipricals and propels heaven and earth, yin and yang to change. The phenomenon of life is also a reciprocal and is lead by YangGi, and so medicine should value Yang Gi. Because the phenomenon of life is lead by this Yang Gi, it is right to base changes of diseases and organize pattern identification. The pattern identification JangGyungAk presented as two Gang six Byun sets its base on YangGi.

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A research on elementary school students with atopic dermatitis in Je-Cheon (제천 지역 소재 초등학교 학생들의 아토피 피부염에 대한 설문조사 연구)

  • Son, Son-Jung;Kim, Hee-Taek;Hong, Seung-Ug
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.22 no.2
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    • pp.163-175
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    • 2009
  • Objective : The aim of this study was to take a census of elementary school children who have atopic dermatitis(AD) especially the residents of Je-Cheon. Method : We conducted a questionnaire survey of the elementary school children in Je-Cheon who have atopic dermatitis. 96 patients with AD were involved in the survey. The questionnaire was made up of their family history, past history, weaning food, breast-fed or not, dietary treatment and Children's Dermatology Life Quality Index(CDLQI), etc. The student's T-test was used for statistical analysis. Results : Parents and siblings brothers and sisters past history has an effect on patients with AD. With regard to past history of patients, allergic rhinitis was the most common ailment. Formula feeding was common in the group under 6 months of age and the mean age of the start of weaning was 7.25 months. Fruit juice and weaning food of powder type were the first weaning foods in this study. Many parents introduced a grain diet, live diet, bone - soup, egg, milk, cheese and bean curd to their children under 12 months of age. A restricted diet was the most common dietary treatment method in this study. The highest scoring question for CDLQI was itching; the lowest one was related to bullying. Conclusion : We analyzed the patients' family history, past history, weaning food, dietary treatment and Children's Dermatology Life Quality Index(CDLQI), etc. Through this survey, we better understand the actual conditions of elementary school children who had AD in Je-Cheon.

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Interpretation of Korean Housing in the Period of Opening the Country to the West and its Modernity Focussed on the Civilization Theory (문명화이론을 통해 본 개항기의 주거와 그 근대성의 재조명)

  • 전남일
    • Journal of Families and Better Life
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    • v.21 no.5
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    • pp.25-40
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    • 2003
  • Since Korea open her ports to the West, she had undergone a great change under the alien influences both on the macro-social and micro-social aspects. This study aims to review the korean housing, corresponding with the everyday life, during the period of transition between the 1876 - 1910 and to interpret its process of modernization and the meaning of modernity. With regards to understand the holistic human relationship and place pf living through history, this study takes the Nobert Elias' Civilization Theory as a theoretical basis. References were therefore, made to various records of foreign missionary at the time, with respect not only to macro sociological changes but also to changes of everyday life. It is of course to take physical and structural aspects of housing architecture into consideration. These works, thus, led to presuming the housing culture of said period. In order to investigate modern character of korean housing, distinctively represented by spatial structure, considerations were made to various architectural examples according to the social and residential status both in urban and rural area. As a results, this paper came to the remarks as follows; 1. It is understood, that the process of modernization is a part of the process of civilization as synthetic process. It is integrated with the change of socio-cultural aspects and everyday life. 2. Korean housing in the said period shows various different residential status and grade of civilization according to the social status as well as economical status. Modern housing was not in general yet. 3. Housing for high classes and middle classes in Seoul shows a tendency of assimilation and imitation after western model. But some examples within the housing of high classes represent its own modernity, that is based on the rationalism and equalization 4. In the housing of lower classes, it was very far from the benefits of civilization. It could analogize from the immature control of disgrace, from undevelopment of individual territory and from uncultivation of rationality in the housing space.