• Journal of Preventive Medicine and Public Health
• /
• v.29 no.2 s.53
• /
• pp.295-309
• /
• 1996

The purpose of this study is to investigate the effect of job stress and social support on the organizational effectiveness of hospital employees and to examine the role of social support in the experience of job stress among the employees. Previous studies have yielded mixed results regarding the role of social support. Some studies provide supporting evidence for the buffering effect of social support, while others do not. Still others report findings about reverse buffering effects. These inconsistent findings are, in part, accounted for by methodological problems such as poor measurement, small sample size, and the existence of high multicollinearity. To examine more rigorously the role of social support in relation to the negative effects of job stress, this study was carefully designed to overcome methodolgical shortcomings found in the past research. In addition, unlike the previous studies, which were concerned mostly with health-related variables as consequences of job stress, in this study, three work-related variables (job satisfaction, organizational commitment, and intent to stay) which had close relationships with organizational effectiveness were examined as output variables. The sample used in this study consisted of 353 employees from a university hospital in the surburbs of Seoul. Data were collected with self-administered questionnaires and analyzed using canonical analysis and hierarchical regression analysis. The results of this study indicate that; (1) job stress has negative main effects on job satisfaction, organizational commitment, and intent to stay; (2) social support has positive main effects on the same three output variables, (3) social support does not moderate the harmful effects of job stress on the three outcome variables, and (4) the three-way interaction effects of (social support * job stress * gender) and of (social support * job stress * education) are not supported. The implications of these findings for the management of human resources are discussed.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.37 no.4
• /
• pp.320-328
• /
• 1992

The soybean yield forcasting models based on climatic elements in six locations were estimated by the STEPWISE/MAXR, Cp statistics and GLM procedure of SAS. The climatic elements were aerial temperature, sunshine hours and precipitation from May to October in 20 years. The investigated six locations were Chunchon, Suwon, Cheongju, Kwangju, Iri and Jinju. The important climatic elements for main effects in Chunchon model were August sunshine hours-linear term, August precipitation-quadratic. June temperature to August precipitation and May temperature to August precipitation were interaction terms. The quadratic August precipitation was assumed to be related to yield in Chunchon. The main effects of Suwon were linear-June temperature, quadratic June sunshine hours and June precipitation. These terms affected yields negatively. The main effects of Cheongju were linear June temperature and quadratic August precipitation. May temperature to June precipitation, July to August precipitations were interactions. The main effects of Kwangju were linear July precipitation, quadratic June temperature and July precipitation. June to July sunshine hours of interaction terms influenced yield negatively. The main effects of Iri were linear May sunshine hours, quadratic May and July sunshine hours. May temperature to May precipitation and June to July precipitations affected yields negatively. The main effects of Jinju were linear June and August precipitations. August temperature to August sunshine hours, June sunshine hours to July precipitation and June to August precipitation were interactions. In linear terms, June and August precipitations and, in interactions, August to August sunshine hours were negative efficacies respectively. The included year variables in Chunchon, Suwon, Kwangju, and Jinju model building were recognized as a linear trend based on an assumption that the technological factors have improved through times.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.22 no.8
• /
• pp.784-790
• /
• 2012

This paper describes a stability and dynamic characteristics of bearingless helicopter main rotor in hover. Baseline rotor configuration is defined and modal analysis for the configuration is taken to verify the dynamic characteristics. The kinematic pitch-lag couplings through ways of pitch link installation are analyzed to know effects on loads, frequencies and stability. The effects of pitch link attachments in spanwise direction and chordwise direction as well as pitch link inclination on thrust, power, flpa-lag-pitch mode frequencies and inplane damping are examined. Pitch link at trailing edge location in chordwise direction has influence on aeroelastic stability of the rotor. Also, the pitch link with negative inclination angle makes inplane damping increase.

• Tribology and Lubricants
• /
• v.20 no.2
• /
• pp.84-90
• /
• 2004

It is very important to improve the durability and reliability of crankshaft because of conflicting demands for lower fuel consumption and higher power output. In this study, for the crankshaft bearing design, analyses were conducted to determine the lubrication characteristics such as oil flow rate, minimum oil film thickness, friction force and increase of oil temperature at main bearing and connecting rod bearing. Additionally, supplied oil pressure and temperature effects on the bearings were simulated to figure out lubrication characteristics on the bearings. Finally the effects of increasing the bearing width and clearance were introduced on the lubrication characteristics.

• Journal of the Korean Home Economics Association
• /
• v.46 no.4
• /
• pp.15-24
• /
• 2008

The main purpose of this study was to examine the main and interaction effects of inhibition, day-care experiences and mothers' controlling child-rearing behavior on young children's social withdrawal in peer situations. A total of 62 young children(34 boys; 28girls) enrolled in day-care center and their mothers participated in this study. Data on child inhibition and parenting were gathered via questionnaires whereas the quality of day-care and social withdrawal were observed in the day-care center. As results, the quality of day-care and mothers' controlling child-rearing behavior were negatively related to social withdrawal. Further, both day-care entry age and the quality of day-care were served as an intervening variables between child inhibition and social withdrawal.

• International Journal of Oral Biology
• /
• v.45 no.2
• /
• pp.33-41
• /
• 2020

Neuroinflammation is known as the main mechanism implicated in the advancement of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. The main feature of neuroinflammation is associated with the activation of microglia. The activated microglia increase proinflammatory cytokine production and induce progressive neuronal cell death. Citrus flavonoids show neuroprotective effects that are associated with the anti-inflammatory action of flavonoids in neurodegenerative diseases. Among these citrus flavonoids, kaempferol, naringin, and nobiletin show inhibitory effects on nuclear factor-κB and mitogen-activated protein kinase signaling pathways that can modulate inflammatory conditions in microglial cells. In the present review, we present the anti-inflammatory activities of citrus flavonoids and therapeutic potential of flavonoids as neuroprotective agents.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.591-596
• /
• 2001

Micron-size mechanical devices are becoming more prevalent, both in commercial applications and in scientific inquiry. Within the last decade, a dramatic increase in research activities has taken place, mostly due to the rapidly expanding growth of applications in areas of MEMS(Micro-Electro-Mechanical Systems), bioengineering, chemical systems, and advanced energy systems. In this study, we have described the effects of vortex viscosity variation on the flowfields in a micro-slot between rotating surfaces of revolution using a micropolar fluid theory. In order to solve this problem, we have used boundary layer equations and applied non-zero values of the microrotation vector on the wall. The results are compared with the corresponding flow problems for Newtonian fluid. Results show that the coefficient $\delta$ controls the main part of velocity ${\upsilon}_x$ and the coefficient M controls the main part of microrotation component ${\Omega}_{\theta}$.

• Archives of Pharmacal Research
• /
• v.27 no.3
• /
• pp.295-299
• /
• 2004

The antifungal activities of the essential oil from Agastache rugosa and its main component, estragole, combined with ketoconazole, one of the azole antibiotics commonly used to treat infections caused by Trichophyton species, were evaluated in this study. The combined effects were measured by the checkerboard microtiter and the disk diffusion tests, against T. erinacei, T. mentagrophytes, T. rubrum, T. schoenleinii and T. soudanense. Susceptibility of the five Trichophyton species to the oil alone, or ketoconazole alone, differed distinctly. The fractional inhibitory concentration indices (FICI) of ketoconazole combined with estragole or A. rugosa essential oil, against the tested Trichophyton species, were between 0.05 and 0.27, indicating synergistic effects. These drug combinations exhibited the most significant synergism against T. mentagrophytes, with FICIs of 0.05 and 0.09 for estragole and the essential oil fraction from A. rugosa, respectively. Isobolograms based on the data from checkerboard titer tests also indicated significant synergism between ketoconazole and the Agastache oil fraction or estragole, against the Trichophyton species evaluated. Trichophyton susceptibility to ketoconazole was significantly improved by combination with the Agastache rugosa oil fraction or its main component, estragole.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.6
• /
• pp.445-452
• /
• 2002

The goal of this paper Is to characterize the vibration damping induced in a main structure by a large number of sub-oscillators. A simple expression is obtained for the substructure impedance when the number of sub-oscillators approaches Infinity. It is found that the induced damping depends on the total mass of the sub-oscillators resonating in a frequency band of interests and nearly independent of their Individual loss factors. A modal overlapping condition. which corresponds to bandwidths that exceed the spacing of those natural frequencies, is required for the sub-oscillators to have such effects. An impulse response of the system is also considered. When the sub-oscillators lack damping and do not satisfy the modal overlapping condition, the vibratory energy is returned from the sub-oscillators to the main structure at later times. The result of this paper is consistent with that found with the fuzzy structure and SEA framework.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.04a
• /
• pp.394-399
• /
• 2012

This paper describes a stability and dynamic characteristics of bearingless helicopter main rotor in hover. Baseline rotor configuration is defined and modal analysis for the configuration is taken to verify the dynamic characteristics. The kinematic pitch-lag couplings through ways of pitch link installation are analyzed to know effects on loads, frequencies and stability. The effects of pitch link attachments in spanwise direction and chordwise direction as well as pitch link inclination on thrust, power, flpa-lag-pitch mode frequencies and inplane damping are examined. Pitch link at trailing edge location in chordwise direction has influence on aeroelastic stability of the rotor. Also, the pitch link with negative inclination angle makes inplane damping increase.