• Korean journal of communication and information
• /
• v.36
• /
• pp.254-286
• /
• 2006

The purpose of the present study is to examine how visitors of personal web sites evaluate self presentation styles. We hypothesized that visitors' gender, self construals, and self esteem would influence the evaluation (likeability and perceived competence) of the self presentation styles (bragging or positive presentation). The hypothesized models were tested with structural equation modeling. Gender differences among the constructs were also examined through latent mean analysis. The results revealed that females tended to have higher interdependent self construal than males. And the male and the female students showed higher likeability toward the self presentations of the other gender. Regarding perceived competence, women and men perceived the other gender more competent, and especially, women perceived men's bragging presentation more competent. Self construals and self esteem, however, did not show any significant effects, which were inconsistent with the results of the previous studies conducted with offline self presentation styles. One of the main implications of this study is that visitors' gender, among other things, is the most infueltial factor in perceiving and evaluating others' self presentation through personal web sites.

• Sleep Medicine and Psychophysiology
• /
• v.6 no.2
• /
• pp.116-125
• /
• 1999

Objectives: The purpose of this study is to investigate the effect of exercise load on sleep structure and stress hormone secretion during sleep. Methods: Five male physical education students were included in this study after giving their written, informed consents in the Research Institute for Sports Science at the University of Hanyang. All subjects have performed for at least 3 years in a regular aerobic exercises such as football, basketball, and running. The subjects were divided into three groups ; NOE(non-exercise), MDE(middle duration exercise), LDE(long duration excercise). MDE group maintained a total of 120 min exercise, and LDE group maintained a total of 300 min exercise by football, basketball or badminton. All subjects were acclimatized to the experimental sleep condition by spending one night under expermental conditions, including the placement of an intravenous catheter. During the subsequent night(24:00-08:00), somnopolygraphic sleep recordings were obtained, and blood for measuring growth hormone, cortisol, testosterone, and $\beta$-endorphin was collected every 120 min throughout the night. Blood samples were obtained from prominent forearm veins of subjects. Then, the samples were immediately placed in ice and centrifuged within 10 min at 3000 rpm at $4^{\circ}C$. Statistical analyses were performed using the SPSS/$PC^+$. Data were analyzed by one-way ANOVA with repeated measures. Results: No significant differences among groups were observed in sleep latency, total sleep time, stage 2 sleep, and slow wave sleep. However, daytime exercise produced significant changes in stage 1 sleep, REM sleep, stage 2 sleep latency, REM sleep latency and sleep efficiency. Stage 1 sleep, stage 2 sleep latency, and REM sleep latency significantly increased in LDE compared to those of NOE and MDE groups. But the amount of REM sleep significantly decreased in LDE. Sleep efficiency of MDE was higher than those of NOE and LDE. The blood concentrations of growth hormone, testosterone, and cortisol during night sleep were significantly lower in LDE than in NOE. $\beta$-endorphin concentrations in blood during night sleep were not different among groups. Conclusion: The daytime exercise load was significantly related to sleep structure and stress hormone secretion during night sleep. Long duration exercise showed a harmful effect on sleep structure and hormone secretion. However, middle duration exercise had a beneficial effect on sleep structure and hormone secretion during sleep.

• Korean Journal of Social Welfare
• /
• v.50
• /
• pp.131-155
• /
• 2002

The present study investigated the influence of parental behavior on their children's dating violence and the pathways by which parental behavior affected their children's violent acts in their respective dating relationships. The related variables in parental behavior were marital violence, child abuse, and parental support. This study identified whether parental violence and support behavior effected dating violence, and if that dating violence was in any way mediated by conflict resolution skills, depression, or delinquency. In addition, the study examined any differences between males and females that were affected by parental behavior. Subjects included 760 students from 14 of the universities in and around Seoul. The Structural Equation Model(SEM) was employed to fulfill the study objectives. The SEM results were the following: The experience of child abuse was associated with severe forms of dating violence, and was only mediated by delinquent acts. Such outcomes were consistent across genders. In this data set, in contrast to the previous studies, the observation of parental violence was not related to children's violent behavior. According to the analysis of SEM, parental support rather than parental violence was more likely to influence their children's dating violence. The lower the level of parental support the greater the negative affect on children's conflict resolution skills, depression, and delinquency, which in turn had an influence on their dating violence. More specifically, an attitude of parental neglect adversely affected women's conflict resolution skills, and increased the frequency of male delinquent behavior. In the light of these findings, practical implications for decreasing dating violence were discussed.

• Journal of Life Science
• /
• v.16 no.7 s.80
• /
• pp.1090-1096
• /
• 2006

The purpose of this study was to investigate the effects of p. Linteus and C. militaris supplement on lactate, phosphorous, ammonia, MDA(malondialdehyde), GPX(glutathione peroxidase) and TAS(total antioxidant status) following $VO_{2max}$, and 85% $VO_{2max}$ exercise. The 15 male college students were divided into three groups: 5 P. liteus supplied(PL), 5 C. militaris supplied(CM), and 5 placebos supplied(PB) and compared the differences between supplement before and after. Obtained results were as follows: In the exercise performance time, there were no differences in PL, CM and PB groups. Regular supplement of P. linteus or C. militaris partially reduces fatigue induction factors. Also, P. linteus or C. militaris supplement decreases MDA, increases GPX and TAS. Therefore, it can be concluded that P. linteus or C. militaris supplement not only have a pharmacological effect for clinical treatment, but also have a maintenance effects on the tissue oxidant-antioxidant system after exercise.

• Journal of Life Science
• /
• v.21 no.1
• /
• pp.9-14
• /
• 2011

Perceived exertion involves detection and interpretation of sensations arising from the body during physical exercise. Physiological variables such as heart rate and oxygen consumption positively correlate with ratings of perceived exertion (RPE). It is unknown whether the accuracy of predicting exercise intensity from RPE differs between men and women. Therefore, it was examined whether men or women could predict relative exercise intensity, determined by oxygen consumption, more accurately from RPE. Ten male and ten female young adult subjects aged 25.1${\pm}$3.52 yr volunteered to participate. RPE were determined by the Borg 15-category scale, and a standard Bruce treadmill protocol was used to perform graded exercise testing. There was no significant difference in slope means between males and females (p=0.501). No significant difference was observed when plotting rates of perceived exertion (RPE) vs. percentage of $VO_2$ max. The relative maximal oxygen consumptions ($VO_{2max,\;}_{rel}$) were 52.36${\pm}$7.35 ml/kg/min for males and 41.44${\pm}$6.71 ml/kg/min for females, respectively and there was a significantly high difference between the two groups in the relative $VO_{2max}$, as well as figures of 4.05${\pm}$0.36 l/min for males and 2.53${\pm}$0.39 l/min for females in the absolute $VO_{2max}$ in this study. There were no significant differences in slope, y-intercept, and standard error of estimate (SEE) between males and females. No significant difference with RPE according to exercise intensity was found between males and females. However, RPE was a useful predictor of exercise intensity in independent genders.

• The Korean Journal of Physiology
• /
• v.30 no.1
• /
• pp.43-51
• /
• 1996

This study was aimed to elucidate the changes in heart rate variability during treadmill exercise at various speeds and grades by spectral analysis. Thirty-three untrained male college students aged $20{\sim}26\;yr $were employed to exercise on a treadmill using 4 speeds (4.02, 5.47, 6.76 and 8.05 km/h) and 6 grades (0, 4, 8, 12, 16 and 20%). A fixed speed was selected for each session with the grade increased every 3 min. The electrocardiogram, respiration and the stepping activity were continuously recorded through an A/D converter system on the computer disk. Power spectra of heart rate variability (RRV) were obtained by use of a fast Fourier transform algorithm. The frequency domain was divided into 3 bands: $VLF\;(0{\sim}0.04\;Hz),\;LF\;(0.04 {\sim}0.15\;Hz)\;and\;HF\;(0.15{\sim}1.00\;Hz).$ Heart rate was $74.4{\pm}2.1\;beats/min$ at rest and showed a steady increase during treadmill exercise with increasing speed and grade up to $196.7{\pm}5.0\;beats/min.$ Total power of HRV was $35.0{\pm}6.7\;(beats/min)^{2}$ at rest and progressively decreased during exercise down to $1.9{\pm}0.3\;(beats/min)^{2}.$ The %VLF power of HRV was $34.5{\pm}3.7\; %$ at rest and showed no significant change during exercise except for a decrease observed at the highest intensity of exercise. The %LF power was $44.1{\pm}3.0\;%$ at rest and showed a progressive decrease down to $4.5{\pm}1.0\;%$ during those stages of exercise where heart rate was over 135 beats/min. The %HF power was $21.4{\pm}2.9\;%$ at rest and showed a progressive increase up to $87.1{\pm}6.7\;%$ during higher intensity exercise where heart rate was over 165 beats/min. Peak frequency of HF band was $0.200{\pm}0.018\;Hz$ at rest and was shifted to higher frequencies up to $0.909{\pm}0.048\;Hz$ at heart rates greater than 135 beats/min. Respiratory frequency was $18.0{\pm}1.5$ breaths/min at rest and significantly increased during exercise up to $53.0{\pm}3.7$ breaths/min. Stride frequency during treadmill exercise showed an increasing tendency with increasing speed from $55.6{\pm}0.9$ steps/min at 4.02 km/h to $81.2{\pm}0.6$ at 8.05 km/h. It was concluded that total power of HRV decreased progressively with increasing exercise intensity due to the withdrawal of parasympathetic activity. At higher exercise intensity, % LF power decreased and %HF power increased with its peak frequency shifted to higher values in a progressive mode with increasing speed and grade, reflecting a readjustment in the cardiovascular system and the increased respiration and its rate, respectively.