검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 32

        1.
        2016.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We estimate the fractal dimension of the ρ Ophiuchus Molecular Cloud Complex, associated with star forming regions. We selected a cube (v, l, b) database, obtained with J = 1−0 transition lines of 12CO and 13CO at a resolution of 22′′ using a multibeam receiver system on the 14-m telescope of the Five College Radio Astronomy Observatory. Using a code developed within IRAF, we identified slice-clouds with two threshold temperatures to estimate the fractal dimension. With threshold temperatures of 2.25 K (3σ) and 3.75 K (5σ), the fractal dimension of the target cloud is estimated to be D = 1.52–1.54, where P / AD/2 , which is larger than previous results. We suggest that the sampling rate (spatial resolution) of observed data must be an important parameter when estimating the fractal dimension, and that narrower or wider dispersion around an arbitrary fit line and the intercepts at NP = 100 should be checked whether they relate to rms noise level or characteristic structure of the target cloud. This issue could be investigated by analysing several high resolution databases with different quality (low or moderate sensitivity).
        4,000원
        2.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present a multi-dimensional reduction method of the surveyed cube database obtained using a single- dish radio telescope in Taeduk Radio Astronomy Observatory (TRAO). The multibeam receiver system installed at the 14 m telescope in TRAO was not optimized at the initial stage, though it became more stabilized in the following season. We conducted a Galactic Plane survey using the multibeam receiver system. We show that the noise level of the first part of the survey was higher than expected, and a special reduction process seemed to be definitely required. Along with a brief review of classical methods, a multi-dimensional method of reduction is introduced; It is found that the ‘background’ task within IRAF (Image Reduction and Analysis Facility) can be applied to all three directions of the cube database. Various statistics of reduction results is tested using several IRAF tasks. The rms value of raw survey data is 0.241 K, and after primitive baseline subtraction and elimination of bad channel sections, the rms value turned out to be 0.210 K. After the one-dimensional reduction using ‘background’ task, the rms value is estimated to be 0.176 K. The average rms of the final reduced image is 0.137 K. Thus, the image quality is found to be improved about 43% using the new reduction method.
        4,000원
        6.
        2005.12 구독 인증기관 무료, 개인회원 유료
        This study was carried out to evaluate the effects of washing medium, breed and washing temperature of fresh and frozen-thawed boar sperm on mitochondrial activity and membrane integrity by flow cytometry. More than 80% of fresh sperm washed with mTLP-PVA medium at 20℃ exhibited an intact membrane and a functional mitochondrion. With frozen-thawed samples, a large number of sperm showed both damaged membrane (36.4~46.9%) and nonfunctional mitochondrion (55.1~71.1%) in the mTLP-PVA and BTS washing media at 20℃. There were no breed effects of fresh and frozen-thawed sperm on mitochondrial activity and membrane integrity. The percentages of damaged membrane of fresh and frozen sperm, respectively, were higher at 4℃ washing temperature than at 20℃ washing temperature in the mTLP-PVA medium. We found that washing medium and washing temperature of fresh and frozen-thawed boar sperm were important for the analyses of mitochondrial activity and membrane integrity by flow cytometry.
        4,000원
        12.
        2005.03 구독 인증기관 무료, 개인회원 유료
        본 연구는 종모돈의 정액성상 동결-융해 후 정자의 생존성 그리고 혈청 중 FSH, LH, estradiol-17β 및 testosterone 농도에 미치는 품종과 계절의 영향을 조사하여 우수한 종모돈의 선발을 위한 기초자료를 얻고자 실시하였다. 요크셔종이 듀록종보다 봄, 여름, 가을, 겨울에서 정액량이 많았으며, 정액농도에서는 차이가 없었다. 계절별 정액량은 듀록 및 요크셔종에서 봄철이 여름, 가을 및 겨울철에 비하여 많았고, 정자농도는 차이가 없었다. 듀록종과 요크셔종에서 각각 봄철에 생산한 정자가 여름, 가을 및 겨울철에 생산한 정자보다 동결-융해 후 정자운동성 및 정상첨체 비율이 높았다. 한편 듀록종과 요크셔종에서 동결-융해 후 정자운동성은 모든 계절에서 요크셔종이 높게 나타났으나, 정상첨체에서는 차이가 없었다. 혈청 중 FSH의 농도를 비교한 결과 요크셔종이 듀록종보다 모든 계절에서 낮은 농도를 나타내었다. 그러나 두 품종 모두에서 각각 계절 간에 차이가 없었다. 혈청 중 LH와 estradiol-17β의 농도를 비교한 결과 요크셔종과 듀록종 간에 차이가 없었다. 또한 두 품종 모두에서 계절 간에 차이가 없었다. 종모돈의 품종별, 계절별 혈청 중 testosterone의 농도를 비교한 결과 요크셔종이 듀록종보다 모든 계절에서 높게 나타났다. 또한 두품종 모두에서 각각 봄철이 여름, 가을 및 겨울철에 비하여 혈청 중 testosterone의 농도가 높은 것으로 나타났다. 이상의 결과를 종합하여 보면, FSH의 농도가 낮을수록 정액생산량이 높은 것으로 나타났으며, 혈청 중 testosterone의 농도가 높을수록 동결-융해 정자의 운동성 및 정상첨체의 비율이 높은 것으로 나타났다.
        4,000원
        13.
        2004.10 구독 인증기관 무료, 개인회원 유료
        This work was undertaken in order to study the developmental competence of nuclear transfer cat embryo with fetal fibroblast and adult skin fibroblast as donor nuclei. Oocytes wererecovered by mincing the ovaries in Hepes-buffered TCM199 and selected the cumulus oocyte complexes (COCs) with compact cumulus cell mass and dark. Homogenous ooplasm were cultured for maturation in TCM199 + 10% fetal bovine serum (FBS) for 12 hours and used as a source of recipient cytoplast for exogenous somatic nuclei. In Experiment 1, we evaluated the effect donor cell types on the reconstruction and development of cloned embryos. Fusion, first cleavage and blastocyst developmental rate was not different between fetal fibroblast and adult skin cell (71.2 vs. 66.8; 71.0 vs. 57.6; 4.0 vs. 6.1 %, P<0.05). In Experiment 2, cloned embryos were surgically transferred into the oviducts of recipient queens. One of seven recipient queens was delivered naturally 2healthy cloned cats and 1 stillborn from fetal fibroblast cell of male origin after 65 days embryo transfer. One of three recipient queens was delivered naturally 1 healthy cloned cat from adult skin cell of female after 65 days embryo transfer. The cloned cats showed genotypes identical to the donor cell lines, indicating that adult somatic cells can be used for feline cloning.
        4,000원
        15.
        2003.12 구독 인증기관 무료, 개인회원 유료
        This study was carried out to find out the changes on serum concentrations of estradiol-17β, progesterone in primiparous Duroc, Landrace and Yorkshire sows weaned at 7 or 21 days. Also, we compared the litter size at birth and weaning among the breeds weaned after lactation for 7 or 21 days. The estradiol-17β concentrations among the breeds were 6.9∼8.8 pg/ml and 6.4∼8.8 pg/ml after lactation for 7 or 21 days, respectively. The progesterone concentrations ranged from 0.3 ng/ml to 1.6 ng/ml. Duroc sow showed higher progesterone concentration compared with Landrace and Yorkshire sows weaned after lactation for 7 or 21 days. Also, we found out that litter size at birth and weaning, respectively, did not show any differences between day 7 and day 21 of lactation. From the facts mentioned above, it was suggested that very early weaning systems could work with no apparent adverse effect on prolificacy.
        4,000원
        1 2