• Title/Summary/Keyword: Low response

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Analysis of the Effect of Objective Functions on Hydrologic Model Calibration and Simulation (목적함수에 따른 매개변수 추정 및 수문모형 정확도 비교·분석)

  • Lee, Gi Ha;Yeon, Min Ho;Kim, Young Hun;Jung, Sung Ho
    • Journal of Korean Society of Disaster and Security
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    • v.15 no.1
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    • pp.1-12
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    • 2022
  • An automatic optimization technique is used to estimate the optimal parameters of the hydrologic model, and different hydrologic response results can be provided depending on objective functions. In this study, the parameters of the event-based rainfall-runoff model were estimated using various objective functions, the reproducibility of the hydrograph according to the objective functions was evaluated, and appropriate objective functions were proposed. As the rainfall-runoff model, the storage function model(SFM), which is a lumped hydrologic model used for runoff simulation in the current Korean flood forecasting system, was selected. In order to evaluate the reproducibility of the hydrograph for each objective function, 9 rainfall events were selected for the Cheoncheon basin, which is the upstream basin of Yongdam Dam, and widely-used 7 objective functions were selected for parameter estimation of the SFM for each rainfall event. Then, the reproducibility of the simulated hydrograph using the optimal parameter sets based on the different objective functions was analyzed. As a result, RMSE, NSE, and RSR, which include the error square term in the objective function, showed the highest accuracy for all rainfall events except for Event 7. In addition, in the case of PBIAS and VE, which include an error term compared to the observed flow, it also showed relatively stable reproducibility of the hydrograph. However, in the case of MIA, which adjusts parameters sensitive to high flow and low flow simultaneously, the hydrograph reproducibility performance was found to be very low.

Development of Contents for the Activities of Daily Living Training for Life Care - Korean Version (라이프케어를 위한 한국형 일상생활활동훈련치료 콘텐츠 개발)

  • Lee, Chun-Yeop;Park, Young-Ju
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.7
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    • pp.529-538
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    • 2020
  • This study aims to develop of contents for the activities of daily living training - Korean version that reflexes the domestic situation and can be applied to clinical practice. For contents development, a Delphi survey was conducted with 13 experts. In the first Delphi survey, 133 items of activities of daily living training are derived based on previous studies, and then the extracted items are asked to group of experts, and the derived items are answered for actual domestic clinical application. In the second survey, 118 items were added by excluding items with a low content validity ratio (CVR) including the results of the first survey, and adding items that can be derived from other opinions. In the 3rd survey, while presenting the 2nd Delphi survey items as they are, it provides an opportunity to change their opinions by presenting their 2nd response and the 2nd average score of other expert panels, and adding appropriateness and importance together. The data were analyzed to obtain the mean, standard deviation, interquartile range, CVR, convergence, and consensus. Finally, a total of 69 items were selected and 49 items were excluded so that 105 items for CVR 0.54 or higher, 111 items for convergence degree 0.50 or lower, and 70 items for continuity degree 0.75 or higher. Sexual activity, care of others, care of pets, and child rearing are difficult to apply socially and culturally, driving and community mobility cannot be performed within the clinical room, and home establishment and management may have different roles depending on gender, and religious spiritual activities and expression are so personal. For these reasons, these items were found to have low importance or suitability. This study can be usefully used as an indicator on the activities of daily living training - Korean version in clinic or community setting.

Early Growth Characteristics of Quercus rubra Associated with Soil Physicochemical Properties and Meteorological Factors in Six Regions of South Korea (토양 물리·화학적 성질 및 기상인자에 따른 국내 6개 지역의 루브라참나무 초기 생장 특성)

  • Hwang, Hwan Su;Kim, Tae Lim;Oh, Changyoung;Lim, Hyemin;Lee, Il Hwan
    • Journal of Korean Society of Forest Science
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    • v.111 no.3
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    • pp.357-364
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    • 2022
  • We investigated the early growth characteristics of Quercus rubra planted in six regions (Hwaseong, Yangpyeong, Pyeongchang, Samcheok, Chungju, and Gimje) in South Korea in relation to soil physicochemical properties and meteorological factors. Q. rubra (1-0) were planted at a density of 3,000 trees ha-1. The average height, root collar diameter (RCD), and volume of 8-year-old Q. rubra planted in 2014 were 3.52 m, 3.84 cm, and 0.0023 m3, respectively. The growth parameters of Q. rubra were the highest and lowest in Hwaseong and Pyeongchang, respectively. Correlation analysis among the soil physicochemical properties, meteorological factors, and plantation growth characteristics found that pH was the only soil factor negatively correlated with RCD, and the other soil factors were not significantly correlated with the growth characteristics. However, growth characteristics were positively correlated to average temperature from March to October and daily maximum temperature; and they were negatively correlated to altitude, topology, and the number of rainy days from March to October. In particular, the trees planted in Hwaseong area showed the best early growth characteristics because this area had the highest daily maximum temperature, the x average temperature from March to October, the low altitude, and it is located close to the foot of a mountain. In Pyeongchang, the early growth characteristics were negatively affected by winter cold damage because of the high altitude, low daily minimum temperature, and damage by wild animals. In Hwaseong, meteorological factors such as temperature and altitude were more highly correlated to growth characteristics of Q. rubra than the physicochemical soil properties. These results will provide useful information for determining suitable sites for Q. rubra plantations and for predicting early growth characteristics in response to environmental factors.

Changes in Abscisic Acid and Gibberellin Levels during Stratification in Panax ginseng Roots (인삼근의 휴면타파과정에 있어서 Abscisic acid 함량 및 Gibberellin 활성의 변화)

  • Choi, Sun-Young;Lee, Kang-Soo;Ryu, Jeom-Ho
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.34 no.1
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    • pp.7-13
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    • 1989
  • The present study was carried out to get the basic information for clarifying physiological mechanism of breaking dormancy and sprouting in Panax ginseng roots. Changes in Abscisic acid (ABA) content and Gibberellin (GA) activity were investigated in one-year-old root during stratification at 4$^{\circ}C$. 15$^{\circ}C$. and 15$^{\circ}C$ after 60day-treatment at 4$^{\circ}C$. Sprouting rate at 15$^{\circ}C$ was 35% in 30days storage at 4$^{\circ}C$ and 100% in longer than 60days, but there was no sprout in both the constant treatment at 4$^{\circ}C$ or 15$^{\circ}C$ regardless of the treatment period. The longer the period of low temperature treatment. number of days to the first and 50% sprouting was shortened, and number of days to 50% from first sprouting was also shortened. ABA content in the upper part of root(contained bud) was gradually increased at both 4$^{\circ}C$ and 15$^{\circ}C$ as the treatment period was extended. and the degree of increase was higher at 15$^{\circ}C$. In the lower part. it showed a slight increase at 15$^{\circ}C$. while showed little change at 4$^{\circ}C$ throughout the treatment period. In the 15$^{\circ}C$ treatment after 60days at 4$^{\circ}C$, it was greatly increased in the upper part. while rather slightly decreased in the lower part of root. GA activity in the upper part was gradually decreased at both 4$^{\circ}C$ and 15$^{\circ}C$, and the degree of decrease was higher at 15$^{\circ}C$. In the lower part. it was similar tendency to those in the upper part. In the 15$^{\circ}C$ treatment after 60days at 4$^{\circ}C$. it was remarkably increased in both the upper and lower part. The increase was great in the low Rf region, while the decrease appeared relatively in the high Rf region compared to those of 60day-treatment at 4$^{\circ}C$. The above results indicated that the breaking dormancy and sprouting of bud were closely associated with the degree of GA activities in response to temperature condition .during stratification rather than the direct effect associated with the changes in ABA content.

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Review on the impact of Arctic Amplification on winter cold surges over east Asia (북극 온난화 증폭이 겨울철 동아시아 한파 발생에 미치는 영향 고찰)

  • Seong-Joong Kim;Jeong-Hun Kim;Sang-Yoon Jun;Maeng-Ki Kim;Solji Lee
    • The Korean Journal of Quaternary Research
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    • v.33 no.1_2
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    • pp.1-23
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    • 2021
  • In response to the increase in atmospheric carbon dioxide and greenhouse gases, the global mean temperature is rising rapidly. In particular, the warming of the Arctic is two to three times faster than the rest. Associated with the rapid Arctic warming, the sea ice shows decreasing trends in all seasons. The faster Arctic warming is due to ice-albedo feedback by the presence of snow and ice in polar regions, which have higher reflectivity than the ocean, the bare land, or vegetation, higher long-wave heat loss to space than lower latitudes by lower surface temperature in the Arctic than lower latitudes, different stability of atmosphere between the Arctic and lower latitudes, where low stability leads to larger heat losses to atmosphere from surface by larger latent heat fluxes than the Arctic, where high stability, especially in winter, prohibits losing heat to atmosphere, increase in clouds and water vapor in the Arctic atmosphere that subsequently act as green house gases, and finally due to the increase in sensible heat fluxes from low latitudes to the Arctic via lower troposphere. In contrast to the rapid Arctic warming, in midlatitudes, especially in eastern Asia and eastern North America, cold air outbreaks occur more frequently and last longer in recent decades. Two pathways have been suggested to link the Arctic warming to cold air outbreaks over midlatitudes. The first is through troposphere in synoptic-scales by enhancing the Siberian high via a development of Rossby wave trains initiated from the Arctic, especially the Barents-Kara Seas. The second is via stratosphere by activating planetary waves to stratosphere and beyond, that leads to warming in the Arctic stratosphere and increase in geopotential height that subsequently weakens the polar vortex and results in cold air outbreaks in midlatitudes for several months. There exists lags between the Arctic warming and cold events in midlatitudes. Thus, understanding chain reactions from the Arctic warming to midlatitude cooling could help improve a predictability of seasonal winter weather in midlatitudes. This study reviews the results on the Arctic warming and its connection to midlatitudes and examines the trends in surface temperature and the Arctic sea ice.

Perceptions of Married Women on Childbirth and Sex Preference and Related Factors in Gyeongju, Korea (도농복합지역 기혼여성들의 출산과 성 선호에 대한 인식 및 관련요인)

  • Youm, Seog-Heon;Kang, Pock-Soo;Kim, Chang-Yoon;Lee, Kyeong-Soo;Hwang, Tae-Yoon;Hwang, In-Sob
    • Journal of agricultural medicine and community health
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    • v.35 no.3
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    • pp.260-273
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    • 2010
  • Objectives: The purpose of this study was to investigate the perceptions of married Korean women regarding marriage and childbirth, and their awareness of childbirth-related issues such as low birth rates, sex preferences and sex imbalances in Korea. Methods: A total of 453 married women aged 20 or older were randomly selected from four urban districts and five rural districts out of 25 districts in Gyeongju, a consolidated city located in Gyeongsangbuk-do Province, South Korea. The survey was conducted from December 2005 to February 2006. A total of 392 out of 453 questionnaires(86.5% response rate) were collected, and 44 incomplete questionnaires were excluded, leaving 348 completed questionnaires to be used for data analysis. Age was divided into three groups as below 49, 50-69, 70 or older. Results: Women's perceptions of marriage were associated with age(p<0.01). Perceptions about childbirth were also significantly related to age(p<0.01), type of residential area (p<0.01) and education level(p<0.05). Sex preferences were significantly related to age(p<0.05) and occupation(p<0.01). Of the respondents aged 49 or younger, 34.8% indicated that the ideal number of children is two, while 25.5% of respondents aged 50 to 69 and 15.3% of respondents aged 70 and 33.7% of respondents aged 70 or older considered four children to be the ideal number. Perceptions of sex imbalance were significantly related to socioeconomic status(p<0.01) and occupation(p<0.01). The largest number of respondents cited "economic burden" as the main reason for low birth rates. Multiple logistic regressions were performed for all three age groups using male sex preference as the dependent variable under the assumption that respondents can have only a single child. Socioeconomic status (p<0.01) and residential area (p<0.05) were significant variables for those aged 49 or below. Education level(p<0.05) and residential area (p<0.01) were statistically significant variables on preferring son in case of having only one child for respondents aged 50 to 69. We did not detect any significant independent variables in respondents who were 70 or older. Conclusions: Our results highlight the necessity of developing policies and public education programs to explain the consequences of low birth rates and sex imbalances in Korea. As increasing numbers of women work outside the home, it is important for the government and employers to provide social and working environments where women do not consider marriage and childbirth to be obstacles to social and business activities.

An experimental study on the impact of an agreement on the means to achieve nursing goals in the early postpartum period of primiparous mothers and enhance their self-confidence and satisfaction in maternal role performance (산욕초기 초산모의 간호목표달성방번 합의가 어머니 역할수행에 대한 자신감 및 만족도에 미치는 영향에 관한 실험적 연구)

  • 이영은
    • Journal of Korean Academy of Nursing
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    • v.22 no.1
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    • pp.81-115
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    • 1992
  • The problem addressed by this study was to determine the effect of nurse - patient agreement on the means to achieve nursing goals in the early postpartum period of primiparous mothers. It was hypothesized that the experimental treatment would result in hegher self-confidence and satisfaction in maternal role performance. This purpose was to contribute to the planning of nursing care to enhance self- confidence and satisfaction in maternal role performance and to the development of relevant nursing theory. Especially, the early postpartum period is crucial toward in recovery from childbirth and attainment of the maternal role. Maternal role attaintment is a complex social and cognitive process of stimulus -response accomplished by learning. Most women attain the maternal role sucessfully. But, some primiparous mothers experience difficultites in attainment of the maternal role due to lack of experience and knowledge. Self-confidence and satisfaction in maternal role performance are important factors in attainment and adjustment to the maternal role (Mercer, 1981a, 1981b ; Lederman, Weigarten, and Lederman, 1981 :Bobak and Jensen, 1985). Nursing is defined as behaviors of nurses add patients that attain nursing goals through action, reaction, interaction, and transaction. For attainment of nursing goals, active participating transactions must occur by agreement on the means to achieve those goals through nurse -patient mutual goal setting and establishment of their active relationships(King, 1981, Ha, 1977). Based on King's theory of goal attainment (1981), this stuy was planned as a non-equivalent control group, non -synchronized quasi -experimental design using agreement on the means to achieve nursing goals in early postpartum as the experimental treatment. The data were collected from July 20 to Sep. 1, 1991 by questionnaires with 60 primiparous mothers planing to breast feed after normal deliveries at W hospital in Pusan, Korea. The subjects were divided into a control group(conventional group) -those admitted from July 20 to Aug. 12, and an experimental group(agreement group) - those admitted from Aug. 13 to Sep. 1. The instument for agreement on the means to nursing goals in the early postpartum period included five steps - identification of disturbances of problems through action, reaction, and interaction with primiparous mothers : mutual early postpartal nursing goal setting : exploration of the means to achieve goals ; agreement on the means (self- care, ealry maternal -infant contact, performance of mothering behavior, and communicating about the infant's behavior and health condition) : implementation of the means. This instrument was developed on the basis of King's elements that lead to transactions in nurse-patient interactions. Lederman et al's (1981) scale for Confidence in ability to cope with tasks of motherhood and Lederman et al's(1981) scale for Mother's satisfaction with motherhood and infant care were used to measure self-confidence and satisfaction in maternal role performance ·with the subjects immediately after admission and on the day of discharge. Self-care performance in the experimental group was measured by self -evaluation tool developed by the investigator from the literature concerned. The tools to measure Pelf-confidence and satisfaction in maternal role performance, and the tool to measure self-evaluation of self-care performance were tested for internal reliability. Cronbach's Alphas were 0.94, 0.94, and 0.63. The data were analysed by using in S.P.S.S. computerized program and included percentage, x²-test, t-test, ANOVA, and Pearson Correlation Coefficient. The conclusions obtained from this study are summerized as follows : 1. The degree of self-confidence in maternal role performance of the total subjects group measured before the experimental treatment was above average with a mean score of 2.77(range 2.14-3.64). Out of 14 items, those with relatively high mean scores were ‘I would like to be a better mother than I am’(3.95), and ‘I have my doubts about whether I am a good mother’(2.87). Those with low mean scores were ‘I know that my baby wants most of the times’(2.28), ‘When the baby cries, I can tell what she /he wants’(2.37), and ‘I have confidence in my ability to care for the baby’(2;50). That is, the self - confidence of Primiparous mothers was considerably high in mothering, but rather low in activities concerning the infant care and understanding of the infant behavior. The degree of satisfaction in maternal role performance of the total subjects group measured before the experimental treatment was high with a mean score of 3.18(range 1.92-3.92). Out of 13 items, those with relatively high mean scores were ‘I am glad 1 had this baby now’(3.75), ‘I play with the baby between feedings when s/he is awake and quiet’(3.67), and ‘I enjoy being a mother’(3.27). Those with low mean scores were ‘I am upset about having too many responsibilities as a mother’(2.78), ‘It bothers me to get up for the baby at night’(2.82), and ‘I get annoyed if the baby frequently interrupts my activities’.(2.82), That is, the satisfaction of primiparous mothers was considerably high in mothering and infant care, but rather low in restraints in time or on the mother's self accomplishment and development. 2. Agreement on the means to achieve nursing goals in the early postpartum period included process of mutual goal setting, exploration of the means to achieve goals, and ahreement in concert means to achieve goals based on the mothers' condition, concerns, self-perception of the nurse - patient interactions. In the process of agreement, there was agreement that the means to achieve goals should be through trust and establishment of active relationships with the nurse through identification of problems according to planned nursing goals and active interaction, such as explanations, teaching, changing of opinions, acceptance or rejection of explanations, and proposing of questions. Therefore agreement on the means to achieve nursing goals in the early postpartum period appears to be an effective nursing intervention for primiparous mothers. 3. The degree of self- confidence in maternal role performance of the exprimental group was higher than that of the control group(t=3.95, p<0.01). Out of 14 items, those with higher score in the experimental group were ‘I would like to be a better mother than I am’(t=1.93, p<0.05), ‘I know that my baby wants most of the times’(t=2.75, p<0.01), ‘When the baby cries, 1 can tell what she/he wants’(t=2.10, p<0.05), ‘I have confidence in my ability to care for the baby’(t=3.72, p<0.01), ‘I trust my own judement in deciding how to care for the baby’(t=1.96, p<0.05), ‘I feel that I know my baby and what to do for him /her’(t=2.44, p<0.01), ‘I am concerned about being able to meet the baby's needs’(t=2.87, p<0.01), ‘I know what my baby likes and dislikes’(t=3.26, p<0.01), ‘I don't know to care for the baby as well as I should’(t=2.07, p<0.05), and ‘I am unsure about whether I give enough attention to the baby’(t=3.04, p<0.01), That is, the degree of self-confidence in mothering, activities concerning infant care, and understanding of infant behavior of the experimental group was higher than that of the control group. Therefore, the first hypothesis, that the degree of self-confidence in maternal role performance of the experimental group would be higher than that of the control group, was supported(t=3.95, p<0.01). 4. The degree of satisfaction in the maternal role performance of the exprimental group was higer than that or the control group(t=2.31, p<0.05). Out of 13 items, those with higher score in the experimental group were ‘I am glad I had this baby now’(t=2.29, p<0.05), ‘I enjoy taking care of the baby’(t=2.4g, p<0.01), ‘It is boring for me to care for the baby and do the same thing over and over’(t=2.87, P<0.01), ‘I am unhappy with the amount of time I have for activities other than childcare’(t=2.51, p<0.01), and ‘When bathing and diapering the baby, I would like to be doing something else’(t=2.43, p<0.01). That is, the degree of satisfaction in mothering, infant care, and restraints in time of on the mother's self accomplishment and development in the experimental group was higher than that of the control group. Therefore, the second hypothesis, that the degree of satisfaction in maternal role performance of the experimental group would be higher than that of the control group, was supported(t=2.31, p<0.05). 5. The third hypothesis, that the higher the degree of satisfaction in materenal role performance, the higher the degree of self-confidence in materenal role performance in the experimental group, was supported (r=0.57, p<0.01)

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The Impact of Collective Guilt on the Preference for Japanese Products (집체범죄감대경향일본산품적영향(集体犯罪感对倾向日本产品的影响))

  • Maher, Amro A.;Singhapakdi, Anusorn;Park, Hyun-Soo;Auh, Sei-Gyoung
    • Journal of Global Scholars of Marketing Science
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    • v.20 no.2
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    • pp.135-148
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    • 2010
  • Arab boycotts of Danish products, Australian boycotts of French products and Chinese consumer aversion toward Japanese products are all examples of how adverse actions at the country level might impact consumers' behavior. The animosity literature has examined how consumers react to the adverse actions of other countries, and how such animosity impacts consumers' attitudes and preferences for products from the transgressing country. For example, Chinese consumers are less likely to buy Japanese products because of Japanese atrocities during World War II and the unjust economic dealings of the Japanese (Klein, Ettenson and Morris 1998). The marketing literature, however, has not examined how consumers react to adverse actions committed by their own country against other countries, and whether such actions affect their attitudes towards purchasing products that originated from the adversely affected country. The social psychology literature argues that consumers will experience a feeling called collective guilt, in response to such adverse actions. Collective guilt stems from the distress experienced by group members when they accept that their group is responsible for actions that have harmed another group (Branscombe, Slugoski, and Kappenn 2004). Examples include Americans feeling guilty about the atrocities committed by the U.S. military at Abu Ghraib prison (Iyer, Schamder and Lickel 2007), and the Dutch about their occupation of Indonesia in the past (Doosje et al. 1998). The primary aim of this study is to examine consumers' perceptions of adverse actions by members of one's own country against another country and whether such perceptions affected their attitudes towards products originating from the country transgressed against. More specifically, one objective of this study is to examine the perceptual antecedents of collective guilt, an emotional reaction to adverse actions performed by members of one's country against another country. Another objective is to examine the impact of collective guilt on consumers' perceptions of, and preference for, products originating from the country transgressed against by the consumers' own country. If collective guilt emerges as a significant predictor, companies originating from countries that have been transgressed against might be able to capitalize on such unfortunate events. This research utilizes the animosity model introduced by Klein, Ettenson and Morris (1998) and later expanded on by Klein (2002). Klein finds that U.S. consumers harbor animosity toward the Japanese. This animosity is experienced in response to events that occurred during World War II (i.e., the bombing of Pearl Harbor) and more recently the perceived economic threat from Japan. Thus this study argues that the events of Word War II (i.e., bombing of Hiroshima and Nagasaki) might lead U.S. consumers to experience collective guilt. A series of three hypotheses were introduced. The first hypothesis deals with the antecedents of collective guilt. Previous research argues that collective guilt is experienced when consumers perceive that the harm following a transgression is illegitimate and that the country from which the transgressors originate should be responsible for the adverse actions. (Wohl, Branscombe, and Klar 2006). Therefore the following hypothesis was offered: H1a. Higher levels of perceived illegitimacy for the harm committed will result in higher levels of collective guilt. H1b. Higher levels of responsibility will be positively associated with higher levels of collective guilt. The second and third hypotheses deal with the impact of collective guilt on the preferences for Japanese products. Klein (2002) found that higher levels of animosity toward Japan resulted in a lower preference for a Japanese product relative to a South Korean product but not a lower preference for a Japanese product relative to a U.S. product. These results therefore indicate that the experience of collective guilt will lead to a higher preference for a Japanese product if consumers are contemplating a choice that inv olves a decision to buy Japanese versus South Korean product but not if the choice involves a decision to buy a Japanese versus a U.S. product. H2. Collective guilt will be positively related to the preference for a Japanese product over a South Korean product, but will not be related to the preference for a Japanese product over a U.S. product. H3. Collective guilt will be positively related to the preference for a Japanese product over a South Korean product, holding constant product judgments and animosity. An experiment was conducted to test the hypotheses. The illegitimacy of the harm and responsibility were manipulated by exposing respondents to a description of adverse events occurring during World War II. Data were collected using an online consumer panel in the United States. Subjects were randomly assigned to either the low levels of responsibility and illegitimacy condition (n=259) or the high levels of responsibility and illigitemacy (n=268) condition. Latent Variable Structural Equation Modeling (LVSEM) was used to test the hypothesized relationships. The first hypothesis is supported as both the illegitimacy of the harm and responsibility assigned to the Americans for the harm committed against the Japanese during WWII have a positive impact on collective guilt. The second hypothesis is also supported as collective guilt is positively related to preference for a Japanese product over a South Korean product but is not related to preference for a Japanese product over a U.S. product. Finally there is support for the third hypothesis, since collective guilt is positively related to the preference for a Japanese product over a South Korean product while controlling for the effect of product judgments about Japanese products and animosity. The results of these studies lead to several conclusions. First, the illegitimacy of harm and responsibility can be manipulated and that they are antecedents of collective guilt. Second, collective guilt has an impact on a consumers' decision when they face a choice set that includes a product from the country that was the target of the adverse action and a product from another foreign country. This impact however disappears from a consumers' decision when they face a choice set that includes a product from the country that was the target of the adverse action and a domestic product. This result suggests that collective guilt might be a viable factor for company originating from the country transgressed against if its competitors are foreign but not if they are local.

Shielding for Critical Organs and Radiation Exposure Dose Distribution in Patients with High Energy Radiotherapy (고 에너지 방사선치료에서 환자의 피폭선량 분포와 생식선의 차폐)

  • Chu, Sung-Sil;Suh, Chang-Ok;Kim, Gwi-Eon
    • Journal of Radiation Protection and Research
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    • v.27 no.1
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    • pp.1-10
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    • 2002
  • High energy photon beams from medical linear accelerators produce large scattered radiation by various components of the treatment head, collimator and walls or objects in the treatment room including the patient. These scattered radiation do not provide therapeutic dose and are considered a hazard from the radiation safety perspective. Scattered dose of therapeutic high energy radiation beams are contributed significant unwanted dose to the patient. ICRP take the position that a dose of 500mGy may cause abortion at any stage of pregnancy and that radiation detriment to the fetus includes risk of mental retardation with a possible threshold in the dose response relationship around 100 mGy for the gestational period. The ICRP principle of as low as reasonably achievable (ALARA) was recommended for protection of occupation upon the linear no-threshold dose response hypothesis for cancer induction. We suggest this ALARA principle be applied to the fetus and testicle in therapeutic treatment. Radiation dose outside a photon treatment filed is mostly due to scattered photons. This scattered dose is a function of the distance from the beam edge, treatment geometry, primary photon energy, and depth in the patient. The need for effective shielding of the fetus and testicle is reinforced when young patients ate treated with external beam radiation therapy and then shielding designed to reduce the scattered photon dose to normal organs have to considered. Irradiation was performed in phantom using high energy photon beams produced by a Varian 2100C/D medical linear accelerator (Varian Oncology Systems, Palo Alto, CA) located at the Yonsei Cancer Center. The composite phantom used was comprised of a commercially available anthropomorphic Rando phantom (Phantom Laboratory Inc., Salem, YN) and a rectangular solid polystyrene phantom of dimensions $30cm{\times}30cm{\times}20cm$. the anthropomorphic Rando phantom represents an average man made from tissue equivalent materials that is transected into transverse 36 slices of 2.5cm thickness. Photon dose was measured using a Capintec PR-06C ionization chamber with Capintec 192 electrometer (Capintec Inc., Ramsey, NJ), TLD( VICTOREEN 5000. LiF) and film dosimetry V-Omat, Kodak). In case of fetus, the dosimeter was placed at a depth of loom in this phantom at 100cm source to axis distance and located centrally 15cm from the inferior edge of the $30cm{\times}30cm^2$ x-ray beam irradiating the Rando phantom chest wall. A acryl bridge of size $40cm{\times}40cm^2$ and a clear space of about 20 cm was fabricated and placed on top of the rectangular polystyrene phantom representing the abdomen of the patient. The leaf pot for testicle shielding was made as various shape, sizes, thickness and supporting stand. The scattered photon with and without shielding were measured at the representative position of the fetus and testicle. Measurement of radiation scattered dose outside fields and critical organs, like fetus position and testicle region, from chest or pelvic irradiation by large fie]d of high energy radiation beam was performed using an ionization chamber and film dosimetry. The scattered doses outside field were measured 5 - 10% of maximum doses in fields and exponentially decrease from field margins. The scattered photon dose received the fetus and testicle from thorax field irradiation was measured about 1 mGy/Gy of photon treatment dose. Shielding construction to reduce this scattered dose was investigated using lead sheet and blocks. Lead pot shield for testicle reduced the scatter dose under 10 mGy when photon beam of 60 Gy was irradiated in abdomen region. The scattered photon dose is reduced when the lead shield was used while the no significant reduction of scattered photon dose was observed and 2-3 mm lead sheets refuted the skin dose under 80% and almost electron contamination. The results indicate that it was possible to improve shielding to reduce scattered photon for fetus and testicle when a young patients were treated with a high energy photon beam.

Growth and Development Response of Bell Pepper (Capsicum annum L.) to $CO_2$ Enrichment under Three Different Temperature Regimes (3온도 수준에서의 $CO_2$ 농도 증가에 따른 피망의 생육 반응)

  • Yoon, Seong-Tak
    • Korean Journal of Organic Agriculture
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    • v.15 no.1
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    • pp.71-84
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    • 2007
  • Predicting plant responses to changing atmospheric $CO_2$ and to the possibility of global warming are important concerns. The $CO_2$ concentration of the global atmosphere has increased during the last decades. This increase is expected to result in changes of global temperatures and this will also affect the growth and development of bell pepper (Capsicum annum L.) and other crops. The objective of this study was to evaluate the effects of atmospheric $CO_2$ enrichment and high temperature on the growth and development of bell pepper under three temperature regimes. There was no statistical difference in the days required from seeding to flowering between $CO_2$ treatments, whereas among three temperature regimes, high temperature plots of $35/25^{\circ}C$ showed the shortest days (52.5 days) required from seeding to flowering. The plant height of bell peppers 15 weeks after emergence showed no statistical significance, while plots of $30/20^{\circ}C$ showed the highest plant height among the three temperature regimes. Time-course response of plant height to $CO_2$, enrichment was restrained in high $CO_2$, concentration (800ppm), at the same time higher temperature promoted plant height. Average leaf area per plant of 400ppm was $6,008.8cm^2$ and it was $5,225.1cm^2$ in the plots of 800ppm, showing 15% more leaf area compared to 400ppm $CO_2$ concentration. Leaf dry weight between $CO_2$ concentration and among temperature regimes showed a statistical significance. The average leaf dry weight in the plot of 800ppm showed the highest (44.1g), which was 18.5% higher compared to that of 400ppm (37.2g) and among temperature regimes, it was the highest (49.8g) in the plot of $35/25^{\circ}C$. Above-ground dry weight showed statistical significance between $CO_2$ concentration and among temperature regimes. The average above-ground dry weight of 800ppm $CO_2$ concentration was 141.4g, 17.9% higher compared to 400ppm $CO_2$ concentration (119.9g). Among three temperature regimes, plots of $30/20^{\circ}C$ showed the highest average above-ground dry weight (168.9g), while plots of $35/25^{\circ}C$ were the lowest (102.3g). In the average bell pepper dry weight, 800ppm of $CO_2$ concentration showed higher bell pepper dry weight (59.5g) than that (44.3g) of 400ppm of $CO_2$ concentration. It was judged that high $CO_2$ concentration was profitable fur bell pepper yield and there was a tendency that when there was high $CO_2$, concentration (800ppm), low temperature ($25/15^{\circ}C$) was profitable for bell pepper dry weight, whereas it was the reverse ($30/20^{\circ}C$), in the case of ambient $CO_2$, concentration (400ppm). In the specific leaf area according to $CO_2$, concentration, 800ppm showed 117.4, which was 35.5% higher compared to that (159.1) of 400ppm, showing that leaf becomes thicker as $CO_2$ concentration increases. Regarding correlation coefficients among crop characteristics, leaf area was negatively correlated with the number of bell peppers per plant and bell pepper dry weight, showing that the higher the leaf area, the lower the bell pepper yield. Bell pepper dry weight per plant showed positively significant correlation with the number of bell peppers per plant and total above dry weight, which showed that the higher the number of bell peppers and the total above dry weight, the higher the bell pepper yield.

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