• Title/Summary/Keyword: environmental stress

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An evaluation system for determining the stress redistribution of a steel cable-stayed bridge due to cable stress relaxation at various temperatures

  • Tien-Thang Hong;Duc-Kien Thai;Seung-Eock Kim
    • Steel and Composite Structures
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    • v.46 no.6
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    • pp.805-821
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    • 2023
  • This study developed an evaluation system to explore the effect of the environmental temperature on the stress redistribution produced by cable stress relaxation of structural members in a steel cable-stayed bridge. The generalized Maxwell model is used to estimate stress relaxation at different temperatures. The environmental temperature is represented using the thermal coefficients and temperature loads. The fmincon optimization function is used to determine the set of stress relaxation parameters at different temperatures for all cables. The ABAQUS software is employed to investigate the stress redistribution of the steel cable-stayed bridge caused by the cable stress relaxation and the environmental temperature. All of these steps are set up as an evaluation system to save time and ensure the accuracy of the study results. The developed evaluation system is then employed to investigate the effect of environmental temperature and cable type on stress redistribution. These studies' findings show that as environmental temperatures increased up to 40 ℃, the redistribution rate increased by up to 34.9% in some girders. The results also show that the cable type with low relaxation rates should be used in high environmental temperature areas to minimize the effect of cable stress relaxation.

Development of Stress-tolerant Crop Plants

  • Park, Hyung-In;Kang, Jung-Youn;Sohn, Hee-Kyung;Kim, Soo-Young
    • Journal of Plant Biotechnology
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    • v.4 no.2
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    • pp.53-58
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    • 2002
  • Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, 50-80% of the maximum potential yield is lost by these "environmental or abiotic stresses", which is approximately ten times higher than the loss by biotic stresses. Thus, improving stress-tolerance of crop plants is an important way to improve agricultural productivity, In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.n factors.

Residential Environmental Stress of Multi-Family Housing Dwellers - Focus on the Gwangju City - (아파트 거주자의 주거환경 스트레스 - 광주시를 중심으로 -)

  • Noh, Se-Hee;Kim, Mi-Hee
    • Journal of the Korean housing association
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    • v.19 no.3
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    • pp.1-10
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    • 2008
  • When environmental elements such as heat, light, air, and sound conditions were suited for the human life, it makes for the welfare and comfortableness of dwellers. This study about residential environmental stress based on environmental psychology very importance because dwellers' background characteristics have an impact on their residential environmental stress levels and it was related to dwellers' satisfaction and well-being. Research about stress connected with residential environment is very important. One's residential environment has direct effects not only on the physical environment but also on family values and expectations, actions, attitude etc. The purpose of this paper is to: 1) identify the general trends of residential environmental stress 2) analyze the differences in socio-demographic characteristics and how the physical characteristics of buildings affect stress. The samples in this study consisted of dwellers living in multi-family housing in Gwang-ju, South Korea. The city was divided into 5 districts and used quota sampling. 324 housewives were sampled from the households by self-administered questionnaires. The survey was conducted in December of the year 2006 after the questionnaire was revised based on the results of preliminary survey.

Impact of Environmental Stressors on the Risk for Posttraumatic Stress Disorder and Quality of Life in Intensive Care Unit Survivors (중환자실 환자의 환경적 스트레스 요인이 외상후 스트레스장애 위험도와 삶의 질에 미치는 영향)

  • Cha, Hyo-Jung;Ahn, Sukhee
    • Journal of Korean Critical Care Nursing
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    • v.12 no.1
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    • pp.22-35
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    • 2019
  • Purpose : This study was to determine the levels of environmental stressor, posttraumatic stress disorder, and quality of life in intensive care units (ICU) survivors after intensive care, and to explore the factors affecting posttraumatic stress disorder and quality of life. Methods: With a longitudinal survey design, data were collected from 116 patients who were discharged from the ICU of a university hospital. The environmental stressor, posttraumatic stress disorder, and quality of life were measured immediately following and 1 month after the ICU discharge. Results: Of all the subjects, 16.4% experienced posttraumatic stress disorder after discharge. Multiple regression analysis revealed that ICU environmental stressors, experience of ICU readmission, using psychotropic drugs and narcotic analgesics, and ICU admission after surgery or cardiac intervention accounted for 22.2% of posttraumatic stress disorder. Posttraumatic stress disorder and sedation status when entering ICU accounted for 28.3% of the quality of life 1 month after ICU discharge. Conclusion: Nursing interventions focused on ICU environmental stressors would not only reduce environmental stress but also contribute to the reduction of posttraumatic stress disorder and later improvement of quality of life.

A Mediating Effect of Job Stress Between Physical Environmental Risk and Safety Behavior, and Moderating Effect of Perceived Control (물리적 환경 위험도가 작업자의 안전행동에 미치는 영향, 직무 스트레스의 매개 효과 및 지각된 통제의 조절 효과)

  • Kim, Byung-Jik;Ji, Won-Koo;Jeon, Sang-Gil
    • Journal of the Korean Society of Safety
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    • v.32 no.2
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    • pp.105-111
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    • 2017
  • This research examined if job stress mediates the relationship between physical environmental risk and safety behavior of employees. In addition, we investigated whether perceived control moderates the physical environmental risk-job stress link. In order to test our hypotheses, 1005 employees in various fields of firms were participated. Using structural equation modeling(SEM), we conducted moderated mediation model analysis that elaborately test the hypotheses. The results demonstrated that job stress mediated the physical environmental risk-safety behavior link. Furthermore, the relationship between physical environmental risk and job stress was moderated by perceived control.

Job Stress Levels in Environment Impact Assessment, and Related Factors Including Expert (환경영향평가 전문가의 직무스트레스 수준 및 관련 요인)

  • Ji, Dong-Ha;Jeon, Hye-Ri;Choi, Soo-Hyun;Son, Bu-Soon;Choi, Mi-Suk
    • Journal of Environmental Health Sciences
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    • v.36 no.5
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    • pp.373-382
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    • 2010
  • A number of recent studies have shown that occupational stress is closely associated with increased fatigue and decreased job satisfaction. This study was designed to assess stress in workers in the field of EIA (environment impact assessment) from July 2009 through september 2009, and questionnaires were uesd to analyze the stress scores and identify the primary factors influencing stress in this occupation. The number of respondents was 272 working in the Capital (Seoul and Kyunggido), Chungcheongdo, Jejudo area. A structured questionnaire was used to evaluate the participants' socio-demographics, job-related factors, health-related behaviors, occupational stress, reaction factor (self-perceived fatigue, job satisfaction) and buffer factor (social support). Occupational stress and self-perceived fatigue were assessed using the Korean Occupational Stress Scale-Short Form (KOSS-SF) and the Multidimensional Fatigue Scale (MFS), respectively. The analysis revealed a strong correlation between occupational stress, job satisfaction, and social support, with occupational stress being associated with an increased risk of fatigue and decreased job satisfaction. In the multiple regression analysis(stepwise), the main factors influencing occupational stress were found to be job satisfaction, supervisor, fatigue, working time, no. of personnel, career. The results of this study suggest that occupational stress is a determinant predictor of self perceived fatigue and job satisfaction. Thus, a strong recommendation is made for a stress management program for reduction of occupational stress, and for the development of relevant experts on the health and quality of life of environment impact assessment workers.

Development of Stress-tolerant Crop Plants

  • CHOI Hyung-in;KANG Jung-youn;SOHN Hee-kyung;KIM Soo-Young
    • Proceedings of the Korean Society of Plant Biotechnology Conference
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    • 2002.04a
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    • pp.41-47
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    • 2002
  • Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, $50-80\%$ of the maximum potential yield is lost by these 'environmental or abiotic stresses', which is approximately ten times higher than the loss by biotic stresses. Thus, Improving stress-tolerance of crop plants is an important way to improve agricultural productivity. In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.

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