• 천문학회보
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• 제39권2호
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• pp.51.2-51.2
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• 2014

Ultra faint dwarf galaxies (UFDs) are larger but fainter than globular clusters, being the faintest galaxies in the universe. They have been found only in the Local Group. We report the discovery of an UFD in the intracluster field of the Virgo cluster (Virgo UFD1). It is located near the core of Virgo cluster, and far from any massive galaxies. The color magnitude diagram of resolved stars in Virgo UFD1 shows narrow, metal poor red giant branch (RGB), which is very similar to the UFDs in the Local Group. by comparing RGB in this galaxy with 12 Gyr stellar isochrones, we estimate its distance, $d=16.4{\pm}0.4$ Mpc and mean metallicity, $[Fe/H]=-2.4{\pm}0.4$. We derive its integrated photometric properties and structural parameters : V-band absolute magnitude of $MV=-6.3{\pm}0.2$, effective radius of $84{\pm}7pc$, and central surface brightness of ${\mu}V,0=26.49{\pm}0.09$ mag arcsec-2. These properties are similar to these of Local Group UFDs. Virgo UFD1 is the first UFD discovered beyond the Local Group. These results indicate that it may be a fossil remnant of the first galaxies.

• Journal of applied mathematics & informatics
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• 제26권3_4호
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• pp.779-784
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• 2008

We show that $\mathbb{Z}[\sqrt{-p}]$ is not a unique factorization domain (UFD) but a factorization domain (FD) with a condition $1\;+\;a^2p\;=\;qr$, where a and p are positive integers and q and r are positive primes in $\mathbb{Z}$ with q < p. Using this result, we also construct several specific non-unique factorization domains which are factorization domains. Furthermore, we prove that an integral domain $\mathbb{Z}[\sqrt{-p}]$ is not a UFD but a FD for some positive integer p.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
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• pp.110-113
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• 2005

Under the condition of nutritional deprivation, actively growing cells prepare to enter $G_0$-like stationary phase. Protein modification by phosphorylation/dephosphorylation or ubiqutination contributes to transfer cells from active cell cycle to dormant stage. We show here that Psp1/Sds23, which functions in association with the 20S cyclosome/APC (1) and is essential for cell cycle progression in Schizosaccharomyces pombe (2), is phosphorylated by stress-activated MAP kinase Sty1 and protein kinase A, as well as Cdc2/cyclinB, upon entry into stationary phase. Three serines at the positions 18,333 and 391 are phosphorylated and overexpression of Psp1 mutated on these sites causes cell death in stationary phase. These modifications are required for the binding of Spufd2, a S.pombe homolog of multiubiquitin chain assembly factor E4 in ubiquitin fusion degradation pathway. Deletion of Spufd2 gene led to increase cell viability in stationary phase, indicating that S. pombe Ufd2 functions to inhibit cell growth at this stage to maintain cell viability. Moreover, Psp1 enhances the multiubiquitination function of Ufd2, suggesting that Psp1 phosphorylated by sty1 and PKA kinases is associated with the Ufd2-dependent protein degradation pathway, which is linked to stress tolerance, to maintain cell viability in the $G_0$-like stationary phase.

• 생명과학회지
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• 제19권6호
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• pp.720-727
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• 2009

Bacillus polyfermenticus KJS-2 (B. polyfermenticus KJS-2)를 이용하여 발효된 콩(BP2FS)은 8가지의 병원성균에 대해 항균활성을 가졌다. BP2FS는 돌돔의 배양에 있어 사료첨가제로 사용되었다. 돌돔의 배양시 BP2FS를 투여한 군($6{\times}10^{4}$ cfu $g^{-1}$ 사료)과 투여하지 않은 군으로 나누었으며, 투여한 군은 120일 동안 하루에 두 번씩 투여 하였다. 120일 후에 투여한 군의 돌돔의 몸무게는 67.29${\pm}$12.62 g이었으며 그렇지 않은 군의 몸무게는 56.56${\pm}$8.21 g으로 나타났다. 생존율은 투여한 군(80%)과 투여하지 않은 군(40%)이었다. 폐사한 돌돔의 축적된 양은 투여한 군(18.95%)과 투여하지 않은 군(60.98%)이었다. BP2FS를 투여한 군에서 B. polyfermenticus KJS-2를 돌돔의 장내에서 검출한 결과 $1.04{\times}10^{4}$ cfu $g^{-1}$으로 나타났다. BP2FS를 투여 하지 않은 군의 돌돔에서는 iridovirus에 감염되었을 경우 나타나는 전형적인 증상인 비장과 간에서 비대세포가 관찰 되었다. 이 결과들은 BP2FS는 돌돔의 이리도바이러스에 대한 감염 시 예방효과를 가져온다 할 수 있다.

• 대한수학회보
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• 제53권5호
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• pp.1447-1455
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• 2016

In this note, we mainly discuss the Gorenstein $Pr{\ddot{u}}fer$ domains. It is shown that a domain is a Gorenstein $Pr{\ddot{u}}fer$ domain if and only if every finitely generated ideal is Gorenstein projective. It is also shown that a domain is a PID (resp., Dedekind domain, $B{\acute{e}}zout$ domain) if and only if it is a Gorenstein $Pr{\ddot{u}}fer$ UFD (resp., Krull domain, GCD domain).

• Journal of Information Processing Systems
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• 제17권3호
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• pp.645-657
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• 2021

Along with the rapid development of the economy, the urban scale has extended rapidly, leading to the formation of different types of urban function districts (UFDs), such as central business, residential and industrial districts. Recognizing the spatial distributions of these districts is of great significance to manage the evolving role of urban planning and further help in developing reliable urban planning programs. In this paper, we propose an automatic UFD division method based on big data analysis of point of interest (POI) data. Considering that the distribution of POI data is unbalanced in a geographic space, a dichotomy-based data retrieval method was used to improve the efficiency of the data crawling process. Further, a POI spatial feature analysis method based on the mean shift algorithm is proposed, where data points with similar attributive characteristics are clustered to form the function districts. The proposed method was thoroughly tested in an actual urban case scenario and the results show its superior performance. Further, the suitability of fit to practical situations reaches 88.4%, demonstrating a reasonable UFD division result.

• 대한수학회보
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• 제52권4호
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• pp.1253-1268
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• 2015

It is well known that an integral domain D is a UFD if and only if every nonzero prime ideal of D contains a nonzero principal prime. This is the so-called Kaplansky's theorem. In this paper, we give this type of characterizations of a graded PvMD (resp., G-GCD domain, GCD domain, $B{\acute{e}}zout$ domain, valuation domain, Krull domain, ${\pi}$-domain).

• 대한수학회보
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• 제57권5호
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• pp.1215-1229
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• 2020

Let D be an integral domain and S a multiplicative subset of D. An ascending chain (I_k)_k∈ℕ of ideals of D is said to be S-stationary if there exist a positive integer n and an s ∈ S such that for each k ≥ n, sI_k ⊆ I_n. As a generalization of domains satisfying ACCP (resp., ACC on ∗-ideals) we define D to satisfy S-ACCP (resp., S-ACC on ∗-ideals) if every ascending chain of principal ideals (resp., ∗-ideals) of D is S-stationary. One of main results of this paper is the Hilbert basis theorem for an integral domain satisfying S-ACCP. Also we investigate the class of such domains D and we generalize some known related results in the literature. Finally some illustrative examples regarding the introduced concepts are given.

• 대한수학회지
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• 제54권6호
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• pp.1733-1757
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• 2017

Let $R={\oplus}_{{\alpha}{\in}{\Gamma}}R_{\alpha}$ be an integral domain graded by an arbitrary torsionless grading monoid ${\Gamma}$, ${\bar{R}}$ be the integral closure of R, H be the set of nonzero homogeneous elements of R, C(f) be the fractional ideal of R generated by the homogeneous components of $f{\in}R_H$, and $N(H)=\{f{\in}R{\mid}C(f)_v=R\}$. Let $R_H$ be a UFD. We say that a nonzero prime ideal Q of R is an upper to zero in R if $Q=fR_H{\cap}R$ for some $f{\in}R$ and that R is a graded UMT-domain if each upper to zero in R is a maximal t-ideal. In this paper, we study several ring-theoretic properties of graded UMT-domains. Among other things, we prove that if R has a unit of nonzero degree, then R is a graded UMT-domain if and only if every prime ideal of $R_{N(H)}$ is extended from a homogeneous ideal of R, if and only if ${\bar{R}}_{H{\backslash}Q}$ is a graded-$Pr{\ddot{u}}fer$ domain for all homogeneous maximal t-ideals Q of R, if and only if ${\bar{R}}_{N(H)}$ is a $Pr{\ddot{u}}fer$ domain, if and only if R is a UMT-domain.

• 한국식품저장유통학회지
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• 제24권1호
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• pp.134-144
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• 2017

본 연구는 여주 분말 첨가 된장의 발효 중 이화학적 특성, phytochemical 화합물(isoflavones과 phenolic acids) 및 생리활성 활성 변화를 측정하였다. 된장 발효 중 pH는 6.41-5.83에서 5.81-5.24로 감소하였고, 반면에 산도는 0.42-0.65%에서 1.28-1.48%로 증가하였다. 고초균과 효모 생균수, 염도 및 총 아미노산 함량은 발효 종기(60 일)에 증가하였다. 특히, 발효 후 10% 여주 분말 첨가 된장은 가바(GABA, 129.87 mg/100 g) 함량이 다른 된장 시료들과 비교하여 가장 함량이 높았다. 발효 후 된장은 발효 전 된장 시료보다 생리활성이 높았다. 발효 후 phytochemicals 화합물 중 isoflavone-aglycones과 phenolic acids는 증가하였고, 반면에 isoflavone-glycosides는 감소하였다. 게다가, 발효 후에 총 phenolics, isoflavone-aglycones과 phenolic acids 함량은 급격히 증가하였고, 이에 따라 항산화 활성과 ${\alpha}$-glucosidase 저해활성이 증가하였다. 이들 결과로부터 여주 분말 첨가로 항산화와 항당뇨 활성이 개선된 새로운 타입의 된장 제조가 가능할 것으로 판단되었다.