목적 : 청각자극(Auditory stimulus)이 동반된 상태에서 근시안과 근시성 난시안의 굴절교정이 가독성과 암기력에 영향을 미치는지에 대해 확인해보고자 하였다. 방법 : 대상자는 건강한 성인 중 구면굴절력이 -1.00 D 이상의 근시안 31명(평균 연령: 22.16±1.32세)과 원 주굴절력이 -1.00 D 이상의 근시성 난시안 29명(평균 연령: 23.04±1.40세), 총 60명으로 평균 등가구면굴절력은 -4.56±2.49 D이었다. 굴절상태는 시험안경테(TLS-AF, Topcon, Japan)로 완전 교정한 상태, 차폐한 상태 및 구면굴절력과 원주굴절력을 각각 -1.00 D 만큼 저교정한 상태로 조정하고, 이 상태에서 각각 4.5 m의 거리에 규칙성이 없는 일련의 단음절 시표를 보여주면서 시표의 글자와 동일하게 녹음된 음성을 일정한 속도로 들려준 상 태에서 피검사자가 암기한 음절의 개수를 암기력으로 측정하였다. 결과 : 근시안을 대상으로 완전교정, 구면굴절력 -1.00 D 저교정 및 양안 차폐 상태에서 암기력은 각각 15음절 중 6.03±1.87개, 3.30±1.42개, 3.70±1.79개, 난시안을 대상으로 완전교정, 구면굴절력 -1.00 D 저교정 및 양안 차폐상태에서 암기력은 6.11±1.76개, 3.81±1.21개, 4.48±2.05개로 근시안과 근시성 난시안에서 모두 저교정 상태에서의 암기력은 완전교정상태보다 저하되었고 차폐상태와 유사하였다. 암기력은 근시도 및 난시도에 따라 차이가 없었다. 또한 근시성 난시안에서 구면굴절력과 원주굴절력을 각각 저교정 상태에서의 암기력은 차이가 없었다. 결론 : 근시안 및 근시성 난시안의 굴절이상이 저교정된 경우 암기력이 유의하게 저하되었다. 따라서 암기력을 필요로 하는 작업을 효율적으로 수행하기 위해서는 정확한 시력교정이 필요하다고 생각한다.

An attempt has been made to analyze time series of Hα, Hβ, and Hɤ line profiles taken from a 3B/X6.1 flare which occurred on Oct. 27, 1991 in an active region, NOAA 6891. A total of 22 sets of Hα, Hβ, and Hɤ taken with a low and non-uniform time resolution of 10-40 seconds were scanned by PDS with absolute intensity calibration to derive the physical characteristics of the material in the flare chromosphere. Our . results are as follows: (1) The lower Balmer lines observed during the flare activity are broadened by Stark effect. (2) At the peak of the flare activity, the electron temperature of the Balmer line emitting region reaches up to 35000K and its geometrical thickness increases to a scale of ~104km, suggesting that high energy particles penetrate deep into the photospheric level.

In this study, we investigated the characteristics of CCK-producing cells and mucus-secreting goblet cells with respect to stomach fish and stomachless fish of the Gobiidae in order to provide a basis for understanding the digestive physiology. Hairychin goby (Sagamia geneionema), which is stomachless fish, the numbers of mucus-secreting goblet cells is highest in the posterior intestine portion (P<0.05), while CCK-producing cells are scattered throughout the intestine. Gluttonous goby (Chasmichthys gulosus), which is stomach fish, mucus-secreting goblet cells are most abundant in the mid intestine portion (P<0.05), whereas CCK-producing cells are observed only in the anterior and mid intestine portion. Trident goby (Tridentiger obscurus) which is stomach fish, mucus-secreting goblet cells were most abundant in the mid intestine portion (P<0.05). CCK-producing cells are found in the anterior and mid intestine portion. Giurine goby, Rhinogobius giurinus which is also stomach fish, the largest number of mucus-secreting goblet cells showed in anterior intestine portion except for esophagus (P<0.05). CCK-producing cells are present only in the anterior and mid intestine portion. In S. geneionema, digestive action occurs in the posterior intestine portion to protect and functions to activate digestion. In contrast, in C. gulosus, T. obscurus and R. giurinus, their digestive action occurs in the anterior and mid intestine portion to protect and functions to activate digestion. Further studies of the modes of food ingestion by these fish, the contents of their digestive tracts, and the staining characteristics of the goblet cells need to be carried out.

Light characteristics are very specific in the aquatic environment. Fish vision and different light spectra perception are related to each species’ natural habit. Light is one of the main environmental conditions and can be easily manipulated in artificial rearing settings. Mucus-secreting goblet cells are the main regulators of digestion. In this study, we established whether the light spectrum (natural condition, full spectrum: green, 520 nm; red, 590 nm, and blue, 480 nm) influences growth performance and digestive activity related to mucus-secreting goblet cell activity in order to develop a good management protocol and optimal rearing system for nursery stage of Epinephelus akaara. For each light spectrum, fish (11.5 ± 0.2 g in mean initial body weight, 9.0 ± 0.1 cm mean initial total length) were reared 16 weeks under a flow-through system and fed commercial pellet diets twice daily. At the end of the experiment, the final body weights differed among the fish reared under different light spectra. The highest growth performance value and feed efficiency were observed in fish reared under the green light condition. Mucus-secreting goblet cell activity was significantly higher in the fish under green light condition than in the fish under the natural, red, and blue light conditions. Rearing of E. akaara under the green light condition had positive effects on fish growth performance and digestion. We recommend that the appropriate light spectrum for nursery stage of E. akaara is the green light condition from the perspective of growth performance and the synergistic effects of mucus-secreting goblet cells. However, longer light treatment periods are needed in future investigations to clarify the effects of light spectrum on each growing stage of E. akaara.

As a preliminary investigation into the effect of environmental factors control for gonadal development, we examined the involvement of photoperiod and water temperature in ovarian development of Epinephelus. akaara. For the induction of sexual maturation, E. akaara reared in recirculating aquaculture system (RAS). During November 2013, the photoperiod and water temperature was adjusted to 12L:12D and 18℃, respectively. In the photo-thermal treatment group, every 3 weeks daylight was increased as follows a 13L:11D and 14L:10D, and control group was maintained under natural condition. After 9 weeks, water temperature was increased 23℃ in photo-thermal treatment group. The sampled fish every 3 weeks revealed increase in gonadosomatic index (GSI; 5.18±1.38), oocyte diameter and vitellogenic oocytes (423.9±36.1 ㎛) were observed in gonads 12 weeks under photo-thermal treatment group. However, ovarian development was maintained immature stage in control group. In this environmental factors manipulation trial, seventy one of the 95 females (578.4 ± 25.4 g in mean body weight, 31.0 ± 0.5 cm mean total length) treated with HCG injection (doses 500 IU/kg BW) were induced ovulation by artificial stripping. The total volume of ovulated eggs were 3,470 ml and the total volume of fertilized eggs was 3,295 ml. The fertilization rate and hatching rate were 95% and 98%, respectively. These results suggest that the photoperiod as well as water temperature are major environmental factors in triggering the gonadal development of E. akaara.

Light characteristics are very specific in the aquatic environment. Fish vision and different light spectra perception are related to each species’ natural habit. Light is one of the main environmental conditions and can be easily manipulated in artificial rearing settings. Cholecystokinin (CCK) and mucus-secreting goblet cells are the main regulators of digestion. In this study, we established whether the light spectrum (natural condition, full spectrum: green, 520 nm; red, 590 nm, and blue, 480 nm) influences growth performance and digestive activity related to CCK mRNA expression and mucus-secreting goblet cell activity in order to develop a good management protocol and optimal rearing system for the longtooth grouper. For each light spectrum, fish were reared 12 weeks under a flow-through system and fed commercial pellet diets once daily. At the end of the experiment, the final body weights differed among the fish reared under different light spectra. The highest growth performance value was observed in fish reared under the green light condition. On the other hand, the growth performances of fish in the natural and blue light conditions were drastically decreased in last 3 weeks of the experiment. CCK mRNA expression and mucus-secreting goblet cell activity were significantly higher in the fish under green light condition than in the fish under the natural, red, and blue light conditions. Rearing of the longtooth grouper under the green light condition had positive effects on fish growth performance and digestion. We recommend that the appropriate light spectrum for the artificial culture of the longtooth grouper is the green light condition from the perspective of growth performance and the synergistic effects of CCK and mucus-secreting goblet cells. However, longer light treatment periods are needed in future investigations to clarify the effects of light spectrum on the longtooth grouper. Together with the findings of the present study, such studies would result in better understanding of the digestive physiology and contribute to the development of optimal rearing management for commercial production of the longtooth grouper.