Acetylcholinesterase (AChE, EC 3.1.1.7) plays a vital role in neurotransmission in both vertebrates and invertebrates. AChE is a key enzyme in the insect nervous system, in which the cholinergic system is essential. In addition to its classical synaptic functions, AChE is recently known to play other non-neuronal roles. In vertebrates, only one AChE has been shown to be involved in both neuronal and non-neuronal functions, whereas two different AChEs have been identified from various insect species, and seem to play respective neuronal and non-neuronal functions. In honey bee, for instance, membrane-anchored AChE2 is reported to be responsible for classical synaptic functions, while soluble AChE1 plays non-neuronal functions. In contrast to most insect species expressing two AChEs, Cyclorrhaphan flies are known to possess only a single ace locus. In Cyclorrhapha possessing only one AChE, multiple forms (molecular variation) of Drosophila melanogaster AChE (DmAChE) were recently suggested to be generated via alternative splicing. Among various molecular forms, membrane-anchored dimer has high enzyme activity, whereas soluble monomer is abundantly expressed without catalytic activity. Interestingly, expression of the soluble DmAChE was induced by chemical stress. Based on the results, it can be hypothesized that the generation of multiple isoforms of AChE2, particularly the soluble forms, may have provided alternative protein copies for AChE1, replaced the functions of AChE1 and eventually allowed the loss of AChE1 in Cyclorrhaphan flies.

The Henyey-Greenstein (H-G) phase function, which is characterized by a single parameter, has been generally used to approximate the realistic dust-scattering phase function in investigating scattering properties of the interstellar dust. Draine (2003) proposed a new analytic phase function with two parameters and showed that the realistic phase function is better represented by his phase function. If the H-G and Draine's phase functions are significantly different, using the H-G phase function in radiative transfer models may lead to wrong conclusions about the dust-scattering properties. Here, we investigate whether the H-G and Draine's phase functions would indeed produce significant differences in radiative transfer calculations for two simple configurations. For the uniformly distributed dust with an illuminating star at the center, no significant difference is found. However, up to ~ 20% of difference is found when the central star is surrounded by a spherical-shell dust medium and the radiation of λ < 2000 Å is considered. It would mean that the investigation of dust-scattering properties using the H-G phase function may produce errors of up to ~ 20% depending on the geometry of dust medium and the radiation wavelength. This amount of uncertainty would be, however, unavoidable since the configurations of dust density and radiation sources are only approximately available.

본 연구에서는 복수의 충격응답함수를 유도하고 이를 이용하여 유역의 강우-유출 특성을 분석하였다. 복수의 충격응답함수를 유도하기 위해 경쟁적 충격응답함수라는 개념을 이용하였다. 이 개념에 따르면 각 충격응답함수는 관측된 유출의 모의에 선택되기 위해 서로 경쟁을 하게 된다. 이와 같은 경쟁적 충격응답의 개념은 정선, 영월, 영춘 및 충주댐 등 4개의 유역에 적용하였다. 각각의 유역에 대해 하나에서 세 개까지의 충격응답을 유도하고 아울러 유역의 특성을 고려하