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Parameterization of the Temperature-Dependent Development of Panonychus citri (McGregor) (Acari: Tetranychidae) and a Matrix Model for Population Projection (귤응애 온도발육 매개변수 추정 및 개체군 추정 행렬모형)

  • Yang, Jin-Young;Choi, Kyung-San;Kim, Dong-Soon
    • Korean journal of applied entomology
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    • v.50 no.3
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    • pp.235-245
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    • 2011
  • Temperature-related parameters of Panonychus citri (McGregor) (Acarina: Tetranychidae) development were estimated and a stage-structured matrix model was developed. The lower threshold temperatures were estimated as $8.4^{\circ}C$ for eggs, $9.9^{\circ}C$ for larvae, $9.2^{\circ}C$ for protonymphs, and $10.9^{\circ}C$ for deutonymphs. Thermal constants were 113.6, 29.1, 29.8, and 33.4 degree days for eggs, larvae, protonymphs, and deutonymphs, respectively. Non-linear development models were established for each stage of P. citri. In addition, temperature-dependent total fecundity, age-specific oviposition rate, and age-specific survival rate models were developed for the construction of an oviposition model. P. citri age was categorized into five stages to construct a matrix model: eggs, larvae, protonymphs, deutonymphs and adults. For the elements in the projection matrix, transition probabilities from an age class to the next age class or the probabilities of remaining in an age class were obtained from development rate function of each stage (age classes). Also, the fecundity coefficients of adult population were expressed as the products of adult longevity completion rate (1/longevity) by temperature-dependent total fecundity. To evaluate the predictability of the matrix model, model outputs were compared with actual field data in a cool early season and hot mid to late season in 2004. The model outputs closely matched the actual field patterns within 30 d after the model was run in both the early and mid to late seasons. Therefore, the developed matrix model can be used to estimate the population density of P. citri for a period of 30 d in citrus orchards.

Association between Satisfaction with Assistive Technology Devices and Psychosocial Impact among Some Mentally or Physically Disabled Children (뇌병변 및 지체 장애아의 보조공학기기 사용 만족도와 심리사회적 영향의 관련성)

  • Jang, Kyoung-Lae;Ryu, So Yeon;Park, Jong;Han, Mi Ah
    • Journal of agricultural medicine and community health
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    • v.42 no.3
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    • pp.132-144
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    • 2017
  • Objectives: The purpose of this study was to identify the association between satisfaction with assistive technology devices and psychosocial impact among some mentally or physically disabled children. Methods: The study subjects were 120 disabled children and their primary caregivers who were using rental assistive technology devices in Gwangju and Jeollanam-Do. Data were collected by structured questionnaire composed of general characteristics of subjects, characteristics related with using assistive devices. Quebec User Evaluation of Satisfaction with assistive Technology 2.0 (QUEST 2.0) and Psychosocial Impact of Assistive Device Scale (PIADS). The statistical analysis were performed by descriptive statistics, t-test, ANOVA and Pearson's correlational analysis. Results: The total mean score for QUEST 2.0 was $4.08{\pm}0.66$ (satisfaction with devices, $4.01{\pm}0.70$; satisfaction with the assistive devices service, $4.14{\pm}0.90$) and the mean of PIADS was $1.00{\pm}0.75$ (ability, $0.99{\pm}0.78$; adaptability, $1.04{\pm}0.86$; self-respect, $0.99{\pm}0.74$). The scores of PIADS was statistically significant difference according to usage time of assistive devices. The PIADS was significantly positive correlated with QUEST 2.0 Conclusions: The mentally or physically disabled children reported that the higher level of satisfaction and the more positive impact of psychosocial aspect with assistive technology devices. It would be necessary to perform further studies for addressing the effects of assistive technology devices.

The Relationship between the Nurse's Reward Fit and Job Involvement${\cdot}$Organizational Commitment (간호사의 보상적합도와 직무몰입 ${\cdot}$ 조직몰입정도간의 관계 연구)

  • Kim, Jung-A
    • Journal of Korean Academy of Nursing Administration
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    • v.3 no.2
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    • pp.41-59
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    • 1997
  • This study surveyed nurses' value of reward and recognition level of organizational reward, and measured the fit of both. It also looked into the relationship between the reward fit and attitude of nurses toward their job and organization (job involvement${\cdot}$organizational commitment). It was planned to suggest the alternative of a future reward system. The sample consisted of 625 nurses of 8 private University Hospitals. Data for this study was collected from Mar. 25 to Apr. 17 by structured questionnaire. This study examined the differences of nurses' value of reward by their demographic characteristics, and looked into the relationship between the reward fit and job involvement${\cdot}$organizational commitment. Four instruments and a demographic questionnair were used to collect the data. Developed for myself and repaired by panel of judges, the value of reward scale and organizational reward scale consisted of 34 items on five points Likert-type scale. Developed by Kanungo and repaired by panel of judges, the job involvement scale measured overall job involvement on 7 items. The organizational commitment scale was developed by Mowday et al and repaired by panel of judges on 10 items. The data was analyzed by frequency, percentage, ranking, one-way ANOVA, Pearson's correlation coefficient, Chronbach alpha coefficient, t-test, SNK test, factor analysis with SPSS/PC+ progra,.Major findings are as follows 1. The mean of nurses' value of reward is 4.2435 and job content rewards are seen as the most important(M=4.5532). The following orders are seen as follows; financial rewards(M=4.4181), human realtion rewards(M=4.4130), establishment ${\cdot}$ facilities rewards(M=4.1632), professional rewards(M=4.1117), social status or prestige rewards(M=3.9228), career rewards(M=3.8816). Of 34 indivisual reward factors, the retainment allowance is seen to be thought of as the most important thing. 2. The mean of nurses' actual reward is 2.6035. The actual reward responded to the most extremely offered is job content rewards. The following orders are seen as follows ; human relation rewards(M=2.9420), financial rewards(M=2.7682), professional rewards(M=2.4601), social status or prestige rewards(M=2.3696), career rewards(M=2.3466), establishment ${\cdot}$ facilities rewards(M=1.9364). Of 34 indivisual reward factors, medical insurance benefits are felt to be most extremely offered. 3. The mean of fit of reward is -1.6874 and that means actual reward doesn't egual the value of the reward. What is offered mostly to nurses' value of reward is human relation rewards. The following orders are seen as follows; job content rewards(M=-1.5938), career rewards(M=-1.6381), social status of prestige rewards(M=-1.6382), financial rewards(M=-1.6836), professional rewards(M=-1.6854), establishment${\cdot}$facilities rewards(M=-2.3130). Of 34 indivisual factors, the item of fered most closely to nurses' value of reward is seen as the participation in educational programs at the nursing department of the hospital. 4. The mean of nurses' job involvement is 3.1987 and SD is 0.5667. 5. The mean of murses' organizational commitment is 2.9348 and SD is 0.6124, that is seen as a little lower than job involvement. 6. Significant value of reward differences were found among nurses by their demographic characteristics such as married status, tenure, academic career. 7. The fit of reward was significant related to job involvement and organizational commitment. When generalizing the result of this study, the value of reward, which nurses consider important and appropriate offers a reward that corresponds to the nurses' value of reward. This increases nurses' job and organization devotion further, as well as hospital effectiveness. It appears that nurses have recognized that the present reward offered in hospitals doesn't come up to their expectations so I think it is urgent to plan and perform the new reward system which is in accord with the nurses' reward fit.

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Search for the Meaning of Social Support in Korean Society (Social Support의 한국적 의미)

  • 오가실;서미혜;이선옥;김정아;오경옥;정추자;김희순
    • Journal of Korean Academy of Nursing
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    • v.24 no.2
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    • pp.264-277
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    • 1994
  • In Korea the concept of social support was first used as a research concept in nursing and has not had much application in the clinical field. Another problem is that research on social support has used a direct translation of the words “social support” into Korean as “sawhejuk jiji”. Three questions were posed to direct the re-search. 1) Is there a concept of social support in Korean society? 2) if so, what words or expressions are used to de-scribe it? 3) further, if so, how is social support structured and how does it function? In order to answer the research questions a three-step research methodology was used : The first step consisted of a literature review on re-search related to social support and on information on the background of, and the way of thinking re-lated to interpersonal relations among Korean people. The second step, which was done to identify whether there is a concept of social support in korean society, involved interviewing a sample of the population. The third step involved a panel discussion that included the members of the research team and three consultants, a sociologist, a philosopher and a scholor in korean literature. A review of the literature on interpersonal relationships in traditional korean society identified a four cirole structure that explains interpersonal relationships. The first circle with “me” at the center is the family but here “me” disappears into the “we” that is essential for a cooperative agricultural society. In the second circle are those close to “me” but outside the family. The third circle includes those with whom “I ” have infrequent but regular contact and with whom correct conduct is important. The last circle is all the people with whom “I” have nothing in common. They are excluded in interpersonal relationships. The literature on interpersonal relationships showed that within the traditional Korean society people lived in villages where most people were very familiar with each other. “Yun”, the social network established the connection and “Jung”, the feeling of affection increased with time as the connection was strengthened. In the traditional village psychological support was provided through “Mallaniki”, “Pumashi” and “Kae” with the latter two also providing material support. In modern Korea there are more informal and formal social networks, like social services and community activities on the formal level and cultural and leisure groups along with “kae’s on the informal level. But even with this modern variety of groups, most social support comes from informal networks that resemble the traditiorlal “Pumashi”, “Kai” md “Mallaniki”. The six member research team interviewed 65 people in order to identify whether there is a concept of social support and then analysed their responses. There were 20 different words describing the reception of the social support and these could be grouped into seven major categories : virtuous, fortunate, helped, supported, blessed, attached(receiving affection) and receiving (grace) benevolence. there were 27 words describing the act of social support which could be categorized into seven major categories : love, looking after, affection(attachment), kindness(goodness), faith, psychological help and material help. for the meaning of social support translated as “sawhe juk jiji” there were a total of 14 different answers which could be categorized into 3 major categories : help, agreement, and faith. In third step, the results of the literature review and the answers to the questions were discussed in a pannel. The results of the discussion led to the following definition of social support in Korea which is shaped like a the four sided pyramid on a base. Social support is the apex of the pyramid and four sides are made up of : “do-oom” (both emotional and material help), “jung” (connectedness, or relationship bound by affection, regard or shared common experience ), “midum” (faith or belief in), “eunhae” (kindness or benevolence). The research team identified “Yun”( the basic network of relationships) as the base of the pyramid and as such the foundation for the components of social support in Korean culture. On “Yun” rest the other four components of social support : “Jung”, “Midum”, “Do-oom”, and “Eunhae”, For social support to take place there must be “Yun”. This is an important factor in social support. In private social network “Jung” is an essential factor in social support. But not in the public social network. “Yun” is a condition for “Jung” and “Jung” is the manifestation of support.

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A Study on Factors Influencing The State of Adaptation of The Hemiplegic Patients (편마비 환자의 퇴원후 적응상태와 관련요인에 대한 분석적 연구)

  • 서문자
    • Journal of Korean Academy of Nursing
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    • v.20 no.1
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    • pp.88-117
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    • 1990
  • The purposes of this study are to delineate a profile of the state of a stroke patient's adaptation at 3 months after hospitalization and to explore the relationship between the level of adaptation and the variables which influence the adaptation of hemiplegic patients. To these ends, theoretical framework was derived basically from the stress adaptation model. The basic assumption underlying the level of adaptation is influenced by the presenting focal, contextual and residual stimuli. This group of stimuli is further operationalized and represented by a perception of stress. which is the perceived effect of the disability and by the mediating variables such as sociodemographic factors as an external conditioning variables and perceived social support and hardiness personality characteristics as an internal intervening variables. The dependent varibales in this study is the level of physical, psychological and social adaptation and is hypothesized to be a function of the interaction between 3 sets of variables namely, the perceived disability effect, external conditioning variables and internal intevening varibles. A total of fourty three subjects from 3 general hospitals in Seoul were observed and interviewed with the aid of 7 structured instruments. The data were collected twice on each subject : first at the pre-discharge period arid at 3 months post-discharge from hospital for the second time. The study was carried out for the period from February to August, 1988. The instruments used for the study include 4 existing scales and 3 scales developed by the researcher for this study. They are : 1) The ADL dependency scale and the scale of the clinical physical functions for the assessment of physical adaptation. 2) the SDS(self report of depression) to measure the level of psychological adaptation. 3) The scale for the amount of social activities for the measurement of the level of social adaptation. 4) The scale for the perceived effect of disability for the measurement of the focal stimuli. 5) The health related hardiness scale and the perceived interpersonal support self evaluation list(ISEL) for the measurement of the hardiness personality character and the perceived social support. The data obtained were analyzed using percentage, oneway ANOVA, Pearson coefficients correlation and stepwise multiple regression. The findings provide valuable information about the present level of physical adaptation at 3 months after discharge. The patient revealed a decreased ADL dependency and lowered limitation of physical function as compared with pre - discharge state. Psycholcgically, the average degree of depression at follow up was within normal range of depression. Socially, the amount of social activities was very low. The one way ANOVA and the correlational analysis revealed the relationship between the 3 sets of variables and the adaptation level as follows : 1) The perceived disability effect was related to the degree of the depression and the amount of social activities but was not related to the physical adaptation. 2) Among the sociodemographic variables, sex and education were related to the difference of ADL dependency and the change of physical function. These factors indicate that women more than men and educated more than the less educated were found more independent. The education was also related to the degree of depression suggesting that the higher the educational level, the more well adapted the patients were both physically and psychologically. Age, marital status and job state were not found to be related to the patient's adaptation level. 3) Among the internal intervening variables, the health related hardiness characteristic was related to the differences of ADL dependency, physical functions and the social activities, indicating that the higher the hardiness character the higher the level of physical and social adaptation. 4) The perceived social support, another internal intervening variable, was related to the degree of depression and the social activities. This data suggest that the higher the perception of social support, the better adapted the patients were psychogically and socially. In summarizing the results of the correlational analysis, the level of physical adaptation was influenced by sex, the years of education and the hardiness character. The level of psychological adaptation was influenced by the years of education, the perceived disability effect and the perceived social support. And the level of social adaptation was influenced by the perceived disability effect, the hardiness character and the perceived social support. The stepwise multiple regression analysis shows findings as follows : 1) The most important factor to explain the difference of ADL dependency was sex, indicating females were more independent than males. 2) The most important factor to explain the difference of physical function and the degree of depression was the patient's education level. 3) The strongest explaining factor for the amount of social activities was perceived self esteem(one of the subconcepts of perceived social support). Thus the most important factors influencing the level of adaptation were found to be sex, education, the hardiness character and self esteem. From the above findings, the significance of this study can be delineated as follows : 1) Corroboration of the assumed relationship between the various variables and the adaptation level as suggested in the conceptual model. 2) Support for the feasibility of the cognitive approach for nursing intervention such as hardness character training, counselling and teaching for self-care in the chronic patients.

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The Changes of Types of Nutritional Risk and Nutritional Intake according to Depression and Self-esteem among the Elderly in Chunnam Province (전남지역 노인에서 우울 및 자아존중감의 인식정도에 따른 영양위험도 및 영양소 섭취량의 변화 양상)

  • Kim, Bok-Hee;Jung, Eun
    • Journal of the Korean Home Economics Association
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    • v.46 no.8
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    • pp.97-107
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    • 2008
  • This study was conducted in order to identify the relationship between psychological factors, such as depression and self-esteem, and nutritional status, such as nutritional risk index and nutrient intake, among the elderly in Chunnam Province. The participants were 119 elderly individuals over the age of 65 years who visited the Senior Welfare Center in Chunnam province between January 29 and February 2, 2007. This study was conducted using a structured questionnaire that included, the Center for Epidemiologic Studies Depression Scale (CES-D), General Self Efficacy Scale (GSES), Nutritional Screening Initiative Checklist (NSI checklist), questions pertaining to the general characteristics of the participants and an estimation of nutrient intake using the 24-hour recall method. Data were analyzed by the SPSS program. Analysis of the participant's CES-D scores revealed that 43.7% of the subjects were normal and 56.3% had more than mild depression. The mean GSES score was 45.9 for the entire group of subjects (51.9 for men, 43.6 for women). The mean nutritional risk index value was 4.30 (5.03 for men, 4.01 for women). Analysis of the participant's scores on the NSI checklist revealed that 69.7% of the subjects were normal and 30.3% exhibited a moderate nutritional risk. The CES-D was positively correlated with the NSI checklist (p < 0.05) but negatively correlated with nutrient intake. However, the GSES was negatively correlated with the NSI checklist (p < 0.05), but positively correlated with nutrient intake (P < 0.01 for protein, calcium, phosphorus, zinc etc.). The results of this study indicate that it is necessary to manage psychological factors, including depression and self-esteem, in the elderly in order to decrease their nutritional risk and increase their nutrient intake.

Expression of Human Leukocyte Antigen DQB1*0602 in Korean Patients with Narcolepsy (한국인 기면병 환자의 Human Leukocyte Antigen(HLA) DQB1*0602 발현 빈도)

  • Hong, Seung-Chul;Woo, Young-Sub;Park, Soo-A;Jeong, Jong-Hyun;Han, Jin-Hee;Kim, Leen;Lee, Sung-Pil
    • Sleep Medicine and Psychophysiology
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    • v.8 no.2
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    • pp.107-112
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    • 2001
  • Introduction: Narcolepsy, a sleep disorder characterized by excessive daytime sleepiness and cataplexy, is known to be closely associated with the human leukocyte antigen (HLA) DQB1*0602. Several studies have suggested that HLA-DQB1*0602 is strongly linked with narcolepsy-cataplexy. However, no studies have yet been made on whether HLA DQB1*0602 is associated with Korean patients with narcolepsy. This study was designed to investigate the frequency of HLA-DQB1*0602 of Korean patients with narcolepsy. Methods: Twenty patients were selected (mean age: $28.2{\pm}3.0$, 11 men and 9 women). The patients were confirmed to have narcolepsy by the overnight polysomnography and multiple sleep latency test (MSLT) in addition to their clinical history and symptoms at St. Vincent's Hospital and Korea University Hospital Sleep Disorders Clinic. Any subjects co-morbid with other hypersomnic sleep disorders such as sleep apnea or periodic limb movements during sleep were excluded. Clinical data was collected through a semi-structured interview for narcoleptic patients. All patients and 21 control did HLA typing for the presence of DQB1*0602. Results Obtained were as Follows: 1) Mean sleep latency was 2.4 (${\pm}2.0$ minutes) and mean frequency of sleep-onset REM period was 3.0 (${\pm}1.6$) by MSLT. 2) Characteristic symptoms of narcolepsy investigated were as follows: excessive daytime sleepiness (100%), cataplexy (100%), sleep paralysis (60%), hypnagogic hallucination (70%) and disrupted nocturnal sleep (75%). 3) Strong emotional expression such as laughing (80%) and joking (70%) triggered cataplexy which affects the knee and leg region (80%) and jaw region (30%). 4) HLA-DR2 was found in 90% of patients and 35% in controls. The frequency of HLA-DQB1*0602 in patients and controls was 90%, and 24%, respectively. Conclusions: These results, which exhibit high HLA-DQB1*0602 expression in Korean patients with narcolepsy, suggest that HLADQB1*0602 could be a strong genetic marker in narcolepsy.

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Sleep Habits and Sleep Disorders among the Elderly Between 65-84 years Who are Living in a Part of Pusan (부산광역시 일지역 65-84세 노인 인구에서의 수면습관 및 수면장애에 대한 조사)

  • Yang, Chang-Kook;Yoo, Seung-Yoon;Joo, Young-Hee;Hahn, Hong-Moo
    • Sleep Medicine and Psychophysiology
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    • v.4 no.1
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    • pp.66-76
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    • 1997
  • Objectives : The purpose of this study is to analyse sleep habits and sleep disorders in the elderly population ased 65-84 years. Methods : Epidemiological survey was performed at home by means of semi structured interviews in the city of Pusan, Korea. Subjects were randomly selected. The questionnaire consisted of 128 items including demographic findings, sleep habits, sleep disorders, somatic illnesses, and psychological distresses. Results : (1) The mean retiring time was 10.28 h (SD 1.30 h) and the mean wake-up time was 5.24 h (SD 1.33 h). The mean duration of sleep was 5.63 h (SD 1.80 h). The mean sleep onset time was 44.51 min. The mean frequency of daytime napping was 2.49 (SD 3.23). The subjects reported they woke up an average of 2.05 (SD 1.59) times per night. All of the above results were not related to age or gender. However, the mean frequency of difficulty in initiating/maintaining sleep was 2.2 times for men and 3.2 times for women (p<0.05). (2) The prevalence of insomnia was 57.7% and was not related to age or gender. Difficulty in initiating sleep was the most commonly reported insomnia complaint(52.4%). Early morning awakening was reported by 50.0% of patients and difficulty in maintaining sleep was reported by 45.1% of them. Worrying in bed and physical pain were strong contributing factor to insomnia. Conclusions : The results of our study showed several characteristics of sleep habits in the elderly. Sleep disorder in old age is not inevitable or trivial. Since sleep disturbance in older adults is common and distressing, it has implications for general health and well-being. Active concern and therapeutic intervention for the sleep habits and sleep disorders in the elderly are needed.

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Effect of Major Depressive Disorder and Insomnia on Somatization (주요 우울증과 불면증이 신체화 증상에 미치는 영향)

  • Jun, Jin Yong;Kim, Seog Ju;Lee, Yu-Jin;Cho, Seong-Jin
    • Sleep Medicine and Psychophysiology
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    • v.19 no.2
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    • pp.84-88
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    • 2012
  • Introduction: The objective of the present study was to investigate the independent effects of major depressive disorder (MDD) and insomnia on somatization, respectively. Methods: A total of 181 participants (73 males and 108 females ; mean age $41.59{\pm}8.92$) without serious medical problem were recruited from a community and a psychiatric clinic in Republic of Korea. Subjects were divided into 4 groups based on the Structured Clinical Interview for DSM-IV axis I disorder (SCID-IV) and sleep questionnaire : 1) normal controls (n=127), 2) primary insomnia (n=11), 3) MDD without insomnia (n=14), and 4) MDD with insomnia (n=29). All participants were requested to complete the somatization subscores of the Symptom Checklist-90-Revised (SCL-90-R). Results: There were significant between-group differences in somatization score (F=25.30, p<0.001). Subjects with both MDD and insomnia showed higher somatization score compared to normal control (p<0.001), subjects with primary insomnia (p=0.01), or MDD subjects without insomnia (p<0.001). Subjects with primary insomnia had higher somatization score than normal controls (p<0.01), while there was no significant difference between MDD subjects without insomnia and normal controls. In multiple regression, presence of insomnia predicted higher somatization score (beta=0.44, p<0.001), while there was only non-significant association between MDD and somatization (beta=0.14, p=0.08). Conclusion: In the current study, insomnia was associated with somatization independently from major depression. Subjects with primary insomnia showed higher somatization. Within MDD patients, presence of insomnia was related to higher somatization. Our finding suggests that insomnia may partly mediate the relationship between depression and somatization.

Market Structure Analysis of Automobile Market in U.S.A (미국자동차시장의 구조분석)

  • Choi, In-Hye;Lee, Seo-Goo;Yi, Seong-Keun
    • Journal of Global Scholars of Marketing Science
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    • v.18 no.1
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    • pp.141-156
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    • 2008
  • Market structure analysis is a very useful tool to analyze the competition boundary of the brand or the company. But most of the studies in market structure analysis, the concern lies in nondurable goods such as candies, soft drink and etc. because of the their availability of the data. In the field of durable goods, the limitation of the data availability and the repurchase time period constrain the study. In the analysis of the automobile market, those of views might be more persuasive. The purpose of this study is to analyze the structure of automobile market based on some idea suggested by prior studies. Usually the buyers of the automobile tend to buy upper tier when they buy in the next time. That kind of behavior make it impossible to analyze the structure of automobile market under the level of automobile model. For that reason I tried to analyze the market structure in the brand or company level. In this study, consideration data was used for market structure analysis. The reasons why we used the consideration data are summarized as following. Firstly, as the repurchase time cycle is too long, brand switching data which is used for the market analysis of nondurable good is not avaliable. Secondly, as we mentioned, the buyers of the automobile tend to buy upper tier when they buy in the next time. We used survey data collected in the U.S.A. market in the year of 2005 through questionaire. The sample size was 8,291. The number of brand analyzed in this study was 9 among 37 which was being sold in U.S.A. market. Their market share was around 50%. The brands considered were BMW, Chevrolet, Chrysler, Dodge, Ford, Honda, Mercedes, and Toyota. �� ratio was derived from frequency of the consideration set. Actually the frequency is different from the brand switch concept. In this study to compute the �� ratio, the frequency of the consideration set was used like a frequency of brand switch for convenience. The study can be divided into 2 steps. The first step is to build hypothetical market structures. The second step is to choose the best structure based on the hypothetical market structures, Usually logit analysis is used for the choice best structure. In this study we built 3 hypothetical market structure. They are type-cost, cost-type, and unstructured. We classified the automobile into 5 types, sedan, SUV(Sport Utility Vehicle), Pickup, Mini Van, and Full-size Van. As for purchasing cost, we classified it 2 groups based on the median value. The median value was $28,800. To decide best structure among them, maximum likelihood test was used. Resulting from market structure analysis, we find that the automobile market of USA is hierarchically structured in the form of 'automobile type - purchasing cost'. That is, result showed that automobile buyers considered function or usage first and purchasing cost next. This study has some limitations in the analysis level and variable selection. First, in this study only type of the automobile and purchasing cost were as attributes considered for purchase. Considering other attributes is very needful. Because of the attributes considered, only 3 hypothetical structure could be analyzed. Second, due to the data, brand level analysis was tried. But model level analysis would be better because automobile buyers consider model not brand. To conduct model level study more cases should be obtained. That is for acquiring the better practical meaning, brand level analysis should be conducted when we consider the actual competition which occurred in the real market. Third, the variable selection for building nested logit model was very limited to some avaliable data. In spite of those limitations, the importance of this study lies in the trial of market structure analysis of durable good.

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