This study was conducted to provide the basic information on environment effects on appearance of ichthyoplankton in the Yeongsan River Estuary in Spring and Summer from 2018 to 2020. Data were obtain from the database of ‘Coastal Ecosystem’ in “National Survey of Marine Ecosystem.” Among the abundance ichthyoplankton species, the Gobiidae spp. dominated, accounting for 85% of the total abundances with the secondary dominant species being the Parablennius yatabei, representing 3% of the abundances. Cluster analysis results revealed a composition differentiated between spring and summer. The Yeongsan River Estuary is known to be significantly influenced by the opening and closing of estuarine gates. In this study, the fluctuation in the number of occurrence groups and abundance among the years and season is attributed to the phenomenon of high water temperature period and the freshwater discharge.

A total of 164 individuals of Hippocampus coronatus were collected from an eelgrass bed in Dongdae Bay, Korea from September 2006 to August 2007. The number of individuals of H. coronatus was higher in September 2006. The size of H. coronatus ranged from 2.4 to 9.3cm in height (Ht), and most of individuals were small size below 5cm (Ht). H. coronatus was a carnivore which consumed mainly gammarid amphipods and copepods. Its diets also included a small amount ofmysids, ostracods, brachiopods, caprellid amphipods, bathynellaceas, isopods, tanaids, and ascothoracids. The diets of H. coronatus underwent size-related changes; smaller individuals consumed copepods, while larger individuals ate gammarid amphipods and mysids. The dietary breadth index of H. coronatus was increased with increasing of their size.

귤녹응애(Aculops pelekassi (Keifer))는 제주감귤의 중요한 해충이다. 본 연구는 귤녹응애의 연간 발생소장을 구명하고자 수행하였으며, 습도와 잎의 연령이 밀도증식에 미치는 영향을 검토하였다. 상대습도는 통계적으로 유의하게 귤녹응애 성충의 수명 및 산란에 영향을 주었다. 상대습도 33, 75, 84%에서 수명은 각각 7.5, 14.5, 14.6일 이었고, 산란수는 5.4, 21.5, 27.1개 이었다. 감귤 잎의 연령에 따라 귤녹응애의 증식정도는 유의하게 차이가 있었다. 연령이 40일된 잎에서는 귤녹응애 밀도증식이 가장 높았으며, 4주 후에는 10일된 잎에서 증식된 것과 비교하여 3배 이상 높았다. 눈 인편 틈에서 월동한 귤녹응애 성충은 4월 하순부터 활동을 시작하여 5월 중순경부터 봄에 발아하여 전개되는 잎(봄 잎)에서 발생하기 시작하였고, 6월 중순에는 과실에서 발생이 시작되었다. 잎에서 발생소장은 6월 하순에서 7월 발생최성기를 보였고, 과실에서는 8월 상순 발생 최성기를 보였다. 본 연구결과는 감귤원에서 귤녹응애 방제에 유용하게 활용될 수 있을 것으로 기대되었다.

I briefly review what has been learned from determinations of mean stellar ages and abundances from integrated light studies of early-type galaxies, and discuss some new questions posed by recent data. A short discussion of spectroscopic ages is presented, but the main focus of this review is on the abundances of Fe, Mg, Ca, N, and C, obtained from comparisons of measurements taken in integrated spectra of galaxies with predictions from stellar population synthesis models.

The high-resolution optical region spectroscopic data of the symbiotic nova AG Peg secured with the Hamilton Echelle Spectrograph at the Lick Observatory, have been analyzed along with the International Ultraviolet Explorer UV archive data. We measure about 700 line intensities in the wavelengths of 3859 to 9230Å and identify about 300 lines. We construct pure photoionization models that represent the observed lines and the physical condition for this symbiotic nova. The spectral energy distribution of the ionizing radiation is adopted from stellar model atmospheres. Based on photoionization models, we derive the elemental abundances; C & N appear to be similar to be smaller than the Galactic planetary nebular value while O is enhanced. Our result is compared with the Contini (1997, 2003) who analyzed the UV region spectral data with the shock + ionization model. The Fe abundance appears to be enhanced than that of normal planetary nebulae, which suggests that AG Peg may have formed in the Galactic disk. The models indicate that the temperature of the central star which excite the shell gas may have fluctuated to an unexpected extent during the years 1998 - 2002.