• Fisheries and Aquatic Sciences
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• 제19권10호
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• pp.44.1-44.8
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• 2016

Rockfish, Sebastes schlegelii (mean length $14.53{\pm}1.14cm$ and mean weight $38.36{\pm}3.45g$), were exposed for 4 weeks with the different levels of ammonia in the concentrations of 0, 0.1, 0.5, and 1.0 mg/L at 19 and $24^{\circ}C$. The indicators of growth performance such as daily length gain, daily weight gain, condition factor, and hematosomatic index were significantly reduced by the ammonia exposure and high temperature. The ammonia exposure induced a significant decrease in hematological parameters, such as red blood cell (RBC) count, white blood cell (WBC) count, hemoglobin (Hb), and hematocrit (Ht), whose trend was more remarkable at $24^{\circ}C$. Mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were also notably decreased by the ammonia exposure. Blood ammonia concentration was considerably increased by the ammonia concentration exposure. In the serum components, the glucose, glutamic oxalate transaminase (GOT), and glutamic pyruvate transaminase (GPT) were substantially increased by the ammonia exposure, whereas total protein was significantly decreased. But, the calcium and magnesium were not considerably changed.

• Journal of Information Technology Applications and Management
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• 제24권1호
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• pp.25-32
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• 2017

For repairable software systems, the Mean Time Between Failure (MTBF) is used as a measure of software system stability. Therefore, the evaluation of software reliability requirements or reliability characteristics can be applied MTBF. In this paper, we want to compare MTBF in terms of parameter estimation using Makeham life distribution. The parameter estimates used the least square method which is regression analyzer method and the maximum likelihood method. As a result, the MTBF using the least square method shows a non-decreased pattern and case of the maximum likelihood method shows a non-increased form as the failure time increases. In comparison with the observed MTBF, MTBF using the maximum likelihood estimation is smallerd about difference of interval than the least square estimation which is regression analyzer method. Thus, In terms of MTBF, the maximum likelihood estimation has efficient than the regression analyzer method. In terms of coefficient of determination, the mean square error and mean error of prediction, the maximum likelihood method can be judged as an efficient method.

• 한국발생생물학회지:발생과생식
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• 제24권4호
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• pp.307-316
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• 2020

The purpose of this study is to observe the early life history of Korean Lefua costata and use the result as basic taxonomic research data for balitorid fish. The fertilized eggs were light green color with completely circle shape and mean size was 1.21±0.06 mm (n=30). Immediately after hatching, the size of the larvae was 2.81±0.11 mm (n=5) in mean length, with egg yolk. On the 3rd day after hatching, the preflexion larvae had a mean length of 4.64±0.09 mm (n=5), and their mouth was opened to start feeding. On the 8th day after hatching, a mean length of the postflexion larvae was 9.43±0.46 mm (n=5), the distal part of the notochord was bent to 45°, and 16 fin rays were developed on the caudal fin. On the 31st day after hatching, a mean length of juveniles was 22.3±0.85 mm (n=5), and the number of fin rays was the same as that of adult fish with (iv8) dorsal fins and (iii8) anal fins.

• 한국초지조사료학회지
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• 제41권1호
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• pp.56-61
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• 2021

본 연구는 기 개발된 풀사료 수량예측모델의 기후정밀도 향상을 위하여 지점별 일평균온도 추정의 가능성을 기상대 자료(종관기상관측지점 75개 와 방재기상관측지점 278개)의 연평균기온 및 월평균기온을 이용하여 검토하였다. 연평균기온과 월평균기온은 각각 정규성 확인, 위치정보(경도, 위도 및 해발고도)와의 상관관계 및 다중회귀분석을 실시하였다. 해발고도는 연평균기온 및 월평균기온에도 지속적인 영향을 미치는 것으로 나타났으며, 위도는 6월을 제외한 월평균기온에 영향을 미치는 것으로 나타났다. 경도는 6, 7, 8, 9, 10 및 11월의 월평균기온에 영향을 미치는 것으로 나타났다. 이상의 결과로 부터 일평균기온 추정은 경도, 위도 및 해발고도를 이용하여 가능할 것으로 판단하였다. 본 연구에서 전국의 기상자료를 사용하여 일평균기온의 추정은 가능하지만 보다 정확도를 높이기 위해서는 기상자료를 각 시·도로 세분화하여 적용할 필요가 있다.

• Animal cells and systems
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• 제4권4호
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• pp.329-336
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• 2000

Life table experiments were performed in order to examine the effects of food quality on Moina macrocopa fed with four kinds of algal foods, Botryococcus sp., Scenedesmus subspicatus, Selenastrum capricornutum, and Chlorella sp., at $20^{\circ}C$ . The temperature effects on M. macrocopa were also assessed, feeding Chlorella at $17^{\circ}C$,$20^{\circ}C$,$25^{\circ}C$, and a combination of $28^{\circ}C$ (light) and $25^{\circ}C$ (dark). The cartilaginous Botryococcs cells were Inappropriate food for Moina. Among the foods tested, Chlorella was the food of the best quality in all accounts of life history traits. Moina grown on Chlorella showed higher net reproductive rate ($R_0$), longer mean and maximum longevities, earlier mean age at maturity, longer mean carapace length at maturity, larger mean clutch size, and shorter mean time interval between clutch productions than those grown on Selenastrum and Scenedesmus. An optimal temperature for Moina was $20^{\circ}C$ . When Moina were grown on Chlorella at $20^{\circ}C$, they showed the highest r, the highest $R_0$, the shortest T, the longest mean longevity, the earliest mean age at maturity, the longest mean carapace length at maturity, and the largest mean clutch size. The results of life table experiments showed that the individual and population growth patterns were much more affected by low temperature $17^{\circ}C$, than by high temperature ($\geq 20^{\circ}C$). In the optimal condition, the r value was very high, 5.1 in $d^{-1}$. In conclusion, the food quality and the temperature are the most important factors to govern the size and continuity of Moina population, by which the individual growth rates and reproductivity of members in the population can be controlled to survive in their environment such as small and temporary water bodies in nature.

• 보건교육건강증진학회지
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• 제15권2호
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• pp.105-117
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• 1998

This study was conducted in order to identify quality of life(QL) and it's related factors in college students in Korea. The data were collected at september, 1996, using the instrument of QL. It was measured by a 5-point scale, composed of 20 questions, 4 regions; “the region of task”, “the region of life style”, “the region of mentalㆍemotional health” and “the region of physical health”. The subjects of this study were 413 college students. Data were analyzed with t-test, ANOVA -test using SPSS program. The results were as follows. 1. The lowest mean of QL score was 2.685 in the region of task. And the mean of QL score in the region of life style was 2.772, in the region of mentalㆍemotional health 3.114, in the region of physical health 3.323. 2. There were significant relation between “sex” and “QL” in the regions of task(p〈 .05), mentalㆍemotional health(p〈.01), and physical health(p〈.01), between “resident patterns” and “QL” in the regions of task(p〈.05), life style(p〈.01), and mentalㆍemotional health (p〈.01), between “meal provider” and “QL” in the regions of mentalㆍemotional health(p〈.05), between “monthly pocket money” and “QL” in the regions of mentalㆍemotional health(p〈.05). Mean score of QL on the subjects who exercised regularly was statistically significant higher than others' in the regions of task(p〈 .05) and physical health(p〈 .05). And QL score of working students for money was statistically significant higher than others' in the regions of physical health(p〈.05).

• 한국초등과학교육학회지:초등과학교육
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• 제21권1호
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• pp.135-142
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• 2002

This paper aims to compare the effects of two teaching methods, the discovery-observational(DO) and the expository-observational(EO) instructions, on students learning interest in the life cycle of fruit fly. The subjects, 463 third-graders from two elementary schools in Changwon City, were divided into two groups, the DO group and the EO group. After the instruction on the life of the flies in two different teaching ways, a questionnaire with 13 items was devised regarding the students' interest, and the subjects were asked to respond to it. The results reveal that the general mean score of the DO group is higher than that of the EO group. Also, the DO group obtains the higher mean score in each item, except two items about knowledge learning. The differences of the mean scores of the two types, general as well as item-individual, between the two groups are statistically significant. This suggests that the class about the life cycle of living creatures easily getatable and observable, such as fruit flies, should be student-centered investigatory one, where students themselves collect them and observe the process of their growth and whole cycle.

• 대한기계학회논문집A
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• 제27권1호
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• pp.175-182
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• 2003

The fatigue life of welded joints is sensitive to welding residual stress and complexity of their geometric shapes. To predict the fatigue life more reasonably. the effects of welding residual stress and its relaxation on their fatigue strengths should be considered quantitatively, which are often regarded to be equivalent to the effects of mean stresses by external loads. The hot-spot stress concept should be also adopted which can reduce the dependence of fatigue strengths for various welding details. Considering the factors mentioned above, a fatigue life prediction model using the modified Goodman's diagram was proposed. In this model, an equivalent stress was introduced which is composed of the mean stress based on the hot-spot stress concept and the relaxed welding residual stress. From the verification of the proposed model to real welding details, it is proved that this model can be applied to predict reasonably their fatigue lives.

• 여성건강간호학회지
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• 제17권2호
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• pp.118-125
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• 2011

Purpose: This study was done to identify effects of fatigue and postpartum depression on quality of life in early postpartum mothers. Methods: The data were collected from 130 mothers at four general hospitals in J and M metropolitan cities. Instruments used to collect the data for the study were the Fatigue Scale developed by Pugh (1993); Postpartum Depression Scale developed by Cox, Holden & Sagovsky (1987), and the Quality of Life Scale developed by Hill, Aldag, Hekel, Riner, G., & Bloomfield (2006). Results: Results showed that the mean for fatigue was 56.74, the mean for postpartum depression was $8.00{\pm}4.37$ and mean for quality of life was 19.78. The quality of life variable showed statistically significant differences for the variable: age (F=3.20, p=.026). The relationship between fatigue and quality of life showed a significant negative correlation (r=-.44, p<.001). The relationship between postpartum depression and quality of life also showed a negative correlation (r=-.42, p<.001). The relationship between postpartum depression and fatigue showed a positive correlation (r=.59, p<.001). These factors explained 23% of the variance in quality of life. Conclusion: The results indicate that it is necessary to develop nursing intervention programs to improve quality of life in for early postpartum mothers.

• 한국학교보건학회지
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• 제29권1호
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• pp.1-10
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• 2016

Purpose: The purpose of this study was to identify the mediating effect of stress coping type and self-esteem between life stress and suicidal ideation in nursing college students. The research design was descriptive study. Methods: A set of self-reported questionnaires was completed by 197 nursing college students, including demographic characteristics, life stress, stress coping type, self-esteem, and suicidal ideation. Data was analyzed using t-test, ANOVA, $Scheff{\acute{e}}^{\prime}s$ test, correlation analysis, and regression analysis for mediating effect by SPSS ver. 22. Results: The mean age was 20.9 years. The mean scores were 2.4, 3.6, and 1.7 out of 5 Likert scales for items of life stress, self-esteem, and suicidal ideation, respectively. The mean score for stress coping type was 2.36 out of 4 Likert scales. There was a positive correlation between suicidal ideation and life stress related to tasks, life stress related to interpersonal relationship, and emotion-focused coping of stress coping type (r=.537, p<.01); while a negative correlation between self-esteem and suicidal ideation. emotional-focused coping of stress coping type had a partial mediating effect between life stress related to tasks and suicidal ideation. Also, self-esteem had a partial mediating effect between life stress related to tasks and suicidal ideation as well as between life stress related to interpersonal relationship and suicidal ideation. Conclusion: Based on the finding of this study, it is necessary to apply various program to stress coping skill and self-esteem in order to reduce suicidal ideation in nursing college students.