In order to prevent upper extremity musculoskeletal disorders, effective keyboard selection is an important consideration. The aim of this study was to compare upper extremity muscle activity according to transverse plane angle changes during vertical keyboard typing. Sixteen healthy men were recruited. All subjects had a similar typing ability (rate of more than 300 keystrokes per minute) and biacromion and forearm-fingertip lengths. Four different types of keyboard (vertical keyboard with a transverse plane angle of 60˚, 90˚, or 120˚, and a standard keyboard) were used with a wrist support. The test order was selected randomly for each subject. Surface electromyography (EMG) was used to measure upper extremity muscle activity during a keyboard typing task. The collected EMG data were normalized using the reference contraction and expressed as a percentage of the reference voluntary contraction (%RVC). In order to analyze the differences in EMG data, a repeated one-way analysis of variance, with a significance level of .05, was used. Bonferroni correction was used for multiple comparisons. There were significant differences in the EMG amplitude of all seven muscles (upper trapezius, middle deltoid, anterior deltoid, extensor carpi radialis, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris) assessed during the keyboard typing task. The mean activity of each muscle had a tendency to increase as the transverse plane angle increased. The mean activity recorded during all vertical keyboard typing was lower than that recorded during standard keyboard typing. There was no significant difference in accuracy and error scores; however, there was a significant difference between transverse plane angles of 60˚ and 120˚ with regard to comfort. In conclusion, a vertical keyboard with a transverse plane angle of 60˚ would be effective in reducing muscle activity compared with vertical keyboards with other transverse plane angles.

인공호수(옥정호)에서 2004년 11월부터 2007년 6월까지 월 1회 간격으로 수층별(표층: 0~5 m, 중층: 4~5 m, 하층: 8~10 m)육수학적 요인과 동물플랑크톤군집 동태 및 식물플랑크톤에 대한 섭식 기여율을 파악하였다. 조사기간 동안 수층별 평균 수온은 각각 상층 15.2±7.8℃, 중층 14.5±7.4℃ 그리고 하층은 13.0±6.2℃

1984년부터 1986년 까지 야회에서 큰검정풍뎅이와 참검정풍뎅이의 토양내 수직분포 계절적 변화를 조사하였다. 두 종 모두 란, 섭식지유충 및 성충은 주로 지표에서 10cm깊이에 위치하였으며 유츙이 월동을 위해 밑으로 이동을 시작하는 시기는 10월 하순-11월 상순으로 5cm깊이의 지온이 내외로 떨어진 때였다. 유충의 월동깊이는 큰검정풍뎅이가 10-40cm, 참검정풍뎅이가 30-80cm였다. 큰검정풍뎅이는 월동장소에서 그대로 부하 및 우화하였으나 참검정풍뎅이는 월동 후 이듬해 4월에 다시 지표 가까이로 올라와 섭식 하다 6월하순경 다시 ？으로 이동을 시작하여 10-40cm, 깊이에서 부하 및 우화하여 월동하였다.

We analyze the observations of temperature and ozone measured by the Microwave Limb Sounder (MLS) during the period of 2005–2016, to investigate the vertical structures of temperature and ozone in the stratosphere and mesosphere during stratospheric sudden warming (SSW). We compute the height profiles of the correlation coefficients between 55 height levels of MLS temperature anomalies and compare them with the results of Whole Atmosphere Community Climate Model simulations for three major SSWs. We also construct the temperature and ozone anomalies for the events to investigate the changes in the temperature and ozone distributions with height. There seems to always be a relatively weak but broad negative correlation between the temperature anomaly at 10 hPa and temperature anomalies over the entire mesosphere during the period before SSW events. However, this pattern gets stronger in the lower mesosphere but becomes a positive correlation in the upper mesosphere and lower thermosphere after the onset of SSW. We also found that the temperatures from the simulations show a similar trend to the observational results but with smaller variations and the transition height from negative to positive correlation in the mesosphere is much lower in the simulation than in the actual observations.