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본고(本稿)는 둘 혹은 여러 변수(變數)가 서로 비선형적(非線型的) 인과관계(因果關係)의 특정한 구조를 가질 때 주어진 관측치(觀測値)로부터 인과관계(因果關係)에 관한 올바른 추론(推論)을 유도하기 위한 새로운 이론인 Baek-Brock의 방법(方法)을 소개하고 이것을 통화(通貨), 생산(生産) 및 물가(物價)의 세 변수(變數)에 적용하여 기존의 인과성(因果性) 검정(檢定)과 어떻게 다른 결과를 얻는지 살펴본다. Baek-Brock의 방법(方法)은 일반적으로 두 변수(變數) 사이의 인과관계(因果關係)를 검정(檢定)하는 데 사용될 수 있으나 변수간(變數間)에 내재하는 실제 인과관계(因果關係)가 선형(線型)인 경우 Granger 검정법(檢定法) 등 기존의 방법(方法)이 높은 검정력(檢定力)을 보이므로 여기서는 주로 비선형인과성(非線型因果性) 검정(檢定)에 초점을 맞춘다. 본(本) 검정법(檢定法)은 인과성(因果性) 여부를 조건부확률에 기초하여 정의한 후 개별확률을 상관적분(相關積分) (correlation integral)을 사용하여 추정(推定)토록 하였다. 이 방법(方法)은 변수간(變數間)의 인과관계(因果關係)가 비선형적(非線型的)일 때 유효하다는 장점을 지니나 인과성(因果性)이 없다는 귀무가설하(歸無假說下)에서 표본수에 따른 검정통계량(檢定統計量)의 점근분포(漸近分布), 그릇된 귀무가설(歸無假說)에 대한 최대의 기각력(棄却力)을 창출하는 척도모수(尺度母數)(scale parameter) 등에 관한 이론적 배경이 미흡하다는 단점이 있다. 본고(本稿)에서는 이를 Monte Carlo 시뮬레이션을 실시하여 보완하였다. 통화(通貨), 생산(生産) 및 물가간(物價間)에는 Granger 검정법(檢定法)을 실시했을 경우 통화(通貨)와 생산(生産)만이 서로 인과성(因果性)이 있을 뿐 물가(物價)와 다른 변수간(變數間)의 인과성(因果性) 증거는 희박하였다. 한편 Baek-Brock의 검정법(檢定法)은 이미 벡터자기회귀모형(自己回歸模型)(VAR)을 통해 밝혀진 선형관계(線型關係) 외에 물가(物價)가 생산(生産) 및 통화(通貨)에 미치는 비선형인과성(非線型因果性)에 관한 추가적 정보를 제공해 주고 있으며 구체적으로 그러한 인과관계(因果關係)가 몇 기(期) 후부터 나타나는지 밝혀 준다. 그러나 이를 이용한 구체적인 모형화(模型化)는 추후의 논문을 통해 밝히기로 한다. The purpose of this paper is primarily to introduce a nonparametric statistical tool developed by Baek and Brock to detect a unidirectional causal ordering between two economic variables and apply it to interesting macroeconomic relationships among money, production and prices. It can be applied to any other causal structure, for instance, defense spending and economic performance, stock market index and market interest rates etc. A key building block of the test for nonlinear Granger causality used in this paper is the correlation. The main emphasis is put on nonlinear causal structure rather than a linear one because the conventional F-test provides high power against the linear causal relationship. Based on asymptotic normality of our test statistic, the nonlinear causality test is finally derived. Size of the test is reported for some parameters. When it is applied to a money, production and prices model, some evidences of nonlinear causality are found by the corrected size of the test. For instance, nonlinear causal relationships between production and prices are demonstrated in both directions, however, these results were ignored by the conventional F-test. A similar results between money and prices are obtained at high lag variables.
Kim and Baek (2000) tested the spatial randomness for the earthquake occurrence in the Korean Peninsula by using the nearest-neighbor test statistics and empirical distribution functions. The K-function, however, has obvious advantages over the methods used in Kim and Baek (2000), such as it does not depend on the shape of the study region and is an effective summary of spatial dependence over a wide range of scales. We applied the K-function method for testing the randomness to both of the historical and the instrumental seismicity data. It was found that the earthquake occurrences for historical and instrumental seismicity data are not random and clustered rather than scattered.
농촌지도(rural extension)는 전 세계의 많은 국가에 존재하는 정부기관이다. 농촌지도는 오랜 역사를 가지고 있고, 많은 원조공여국과 원조수원국에 존재한다. 농촌지도는 국제개발협력에서 중요한 농업기관이다. 한국에는 일제강점기에 도입되었고, 현재에도 농림축산식품부 산하 농촌진흥청의 주요 기능 중 하나로 남아 있다. 이 논문은 대표적인 6개 선진 원조공여국의 농촌지도를 비교·연구하였다. 농촌지도는 거의 4천년 동안 진화되어 왔지만, 현대적 농촌지도는 1874년 아일랜드에서 탄생했다. 지도(extension)이라는 용어도 영국에서 처음 사용되었다. 이렇게 탄생한 농촌지도는 제2차 세계대전, 즉 1950년대 이전에 전 세계로 확산된 농촌개발 모델이다. 제2차 세계대전 전에는 영국, 프랑스 등의 유럽의 각국들이 제국주의 하에서 아프리카, 아시아 및 라틴아메리카의 여러 나라들을 강점하여 농촌지도사업을 실시한 경우이다. 제2차 세계대전 이후에는 UN, 미국 등을 통하여 전 세계로 확산되었다. 따라서 일반적으로 제3세계의 근대적 농촌지도사업의 역사를 논할 때는 제2차 세계대전을 기점으로 삼아 그 이전과 이후로 나누고 있다. 그러나 농촌지도는 농촌개발모델이지 농촌개발 이론은 아니다. 농촌개발 이론은 제2차 세계대전 이후 1950년대부터 등장하기 시작했다. Rural extension has a long history and exists in man donor countries and recipient countries. Rural extension is an important government organization for international development cooperation. This papers is a comparative study of representative 6 donor countries. Modern rural extension was born in Ireland in 1874. Rural extension is rural development model which spread all over the world before World War Ⅱ, or 1950. Before World War Ⅱ, European countries, such as Britain, france, and other countries conducted rural extension in colonies in Africa, Asia and Latin America under imperialism. After World War Ⅱ, rural extension spread all over the world through the United States and United Nations(UN).
Receptor activator of nuclear factor-κB ligand (RANKL) is an osteoblast/stromal cell-derived essential factor for osteoclastogenesis. During endochondral bone formation, hypertrophic chondrocytes calcify cartilage matrix that is subsequently resorbed by osteoclasts in order to be replaced by new bone. Hypoxia-induced upregulation of RANKL expression has been previously demonstrated in an in vitro system using osteoblasts; however, the involved mechanism remains unclear in chondrocytes. In the present study, we investigated whether hypoxia regulates RANKL expression in ATDC5 cells, a murine chondrogenic cell line, and hypoxiainducible factor-1α (HIF-1α) mediates hypoxia-induced RANKL expression by transactivating the RANKL promoter. The expression levels of RANKL mRNA and protein, as well as HIF-1α protein, were significantly increased in ATDC5 cells under hypoxic condition. Constitutively active HIF-1α alone significantly increased the levels of RANKL expression under normoxic conditions, whereas dominant negative HIF-1α reduced hypoxia-induced RANKL expression. HIF-1α increased RANKL promoter reporter activity in a HIF-1α binding element-dependent manner in ATDC5 cells. Hypoxia-induced RANKL levels were much higher in differentiated ATDC5 cells, as compared to proliferating ATDC5 cells. These results suggested that under hypoxic conditions, HIF-1α mediates induction of RANKL expression in chondrocytes; in addition, hypoxia plays a role in osteoclastogenesis during endochondral bone formation, at least in part, through the induction of RANKL expression in hypertrophic chondrocytes.
Osteocytes may function as mechanotransducers by regulating local osteoclastogenesis. Reduced availability of oxygen, i.e. hypoxia, could occur during disuse, bone development, and fracture. Receptor activator of nuclear factor-κB ligand (RANKL) is an osteoblast/stromal cell derived essential factor for osteoclastogenesis. The hypoxia induced osteoclastogenesis via increased RANKL expression in osteoblasts was demonstrated. Hypoxic regulation of gene expression generally involves activation of the hypoxia-inducible factor (HIF) transcription pathway. In the present study, we investigated whether hypoxia regulates RANKL expression in murine osteocytes and HIF-1α mediates hypoxia-induced RANKL expression by transactivating RANKL promoter, to elucidate the role of osteocyte in osteoclastogenesis in the context of hypoxic condition. The expression levels of RANKL mRNA and protein, as well as hypoxia inducible factor-1α (HIF-1α) protein, were significantly increased in hypoxic condition in MLO-Y4s. Constitutively active HIF-1α alone significantly increased the levels of RANKL expression in MLO-Y4s under normoxic conditions, whereas dominant negative HIF-1α blocked hypoxia-induced RANKL expression. To further explore to find if HIF-1α directly regulates RANKL transcription, a luciferase reporter assay was conducted. Hypoxia significantly increased RANKL promoter activity, whereas mutations of putative HIF-1α binding elements in RANKL promoter prevented this hypoxia-induced RANKL promoter activity in MLO-Y4s. These results suggest that HIF-1α mediates hypoxia-induced up-regulation of RANKL expression, and that in osteocytes of mechanically unloaded bone, hypoxia enhances osteoclastogenesis, at least in part, via an increased RANKL expression in osteocytes.
This study was conducted to isolate a salt tolerant gene and to develop salt tolerant rice for reclaimed-saline areas through genetic transformation. A rice c/DRE binding factor 4(OsCBF4) cDNA was isolated from rice using RT-PCR. The full-length cDNA of the CBF4 gene consists of 1,429 nucleotides and 274 amino acid residues. In order to develop salt tolerant rice, transgenic rice plants containing the OsCBF4 gene were obtained via Agrobacterium-mediated transformation. The stable incorporation of the OsCBF4 gene into rice genome was confirmed by PCR and Southern analysis. The stable expression of introduced gene was also validated by RT-PCR analysis in T2 plants. Biological assay of T3 progeny of the transgenic plants in Yoshida solution containing 120mM Nacl for 2weeks, confirmed that the OsCBF4 confers salt tolerance to transgenic rice plants. OsCBF4 transgene in the transgenic line CBF4-10 was markedly expressed up to over three-fold in the leaf by 120 mM NaCl treatment. Real-time PCR analysis revealed that the levels of the transgene expression were markedly increased under salt treatment. The transgenic line CBF4-10 which showed highest ability to recover from the saline stress could be used as a potential source for salt tolerance in rice breeding programs
To study fauna of Silla University located in Mt. Baek-yang, we conducted six surveys from 29 May 2011 to 28 April 2012. We found five phyla 41 orders 197 species of animals inhabiting in this area: four phyla 27 orders 163 species of invertebrates and in vertebrates one order six species of fishes, three orders nine species of amphibians and reptiles, six orders 14 species of aves, and four orders five species of mammals. Of these species, some Korean endemic species were included: a fish of Rhodeus uyekii in a pond near main gate of this university, a frog of Rana coreana in a creek near a dormitory, and a rabbit of Lepus coreanus and a water deer of Hydropotes inermis in a grass region near a main stadium. A kind of hawk, Falco tinnunculus as a natural monument (animal) of no. 323-8, was observed on a building of medical and life science. A blue frog of Hyla japonica as a variation was found near a spring resort. Therefore, this area is considered an ecologically important area having a high animal diversity.
Antioxidants either scavenge superoxide and free radicals or stimulate the detoxification mechanisms within cells, resulting in increased detoxification of free radicals formation. Hyperin, isolated from the stem of Uncaria rhynchophylla, prevented oxygen radical formation and inhibited lipid oxidation. The effective concentrations were 31.3μM for a radical scavenging assay and 2.2μM for a microsome assay, cDNA microarray analysis to determine which genes were modulated by hyperin found that 50 genes were upregulated and 37 genes were downregulated in SNU-668 human gastric cancer cells. Among these genes, thirteen genes that were significantly affected by hyperin were verified by RT-PCR for their effect of genetic reprogramming.