• Journal of Embryo Transfer
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• v.6 no.2
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• pp.1-17
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• 1991

It is widely recognized that the embryonic or fetal loss after breeding is common in the cattle and that it is an important factor affecting reproductive efficiency. The causes of this loss have been subject of extensive researches and the results indicate that the embryonic mortality may he primary factor responsible for low pregnancy rates in non-embryo transfer bovine populations as well as embryo transfer programs. However, it's causes are still not clearly understood. The embryonic mortality or pregnancy rate has been influenced by various embryonic and maternal effects related to genetic and environmental factors. The timing and extent of embryonic mortality vanes greatly according to authors and estimating methods, because it is difficult to make direct measurements. The major important factors that may influence the embryonic losses or pregnancy rates after embryo transfer can be summeirized. 1.When an embryo is transferred to unmated recipients, the contralateral transfer to corpus luteum results in a lower survival rate than ipsilateral deposition. When the embryos are transferred for the production of twin calves, their survivals and twin pregnancies have quite inconsistent according to the transfer methods either to the unmated-synchronized or already mated recipients and more works are needed to accurrately clarify the previous results. 2.Although embryos can be cultured in vitro some hours without the great declines in pregnancy rates, the rates differ markedly among culture times and media but may be improved by co-transfer systems. 3.Embryo developmental stages and quality grades clearly affect the survival rate following freezing and the pregnancy rate after transfer and the selection of embryos without chromosome abnormalities and of high fertile semen may also be considered to increase the pregnancy rates. 4.Many researches have attempted to relate the plasma progesterone levels to pregnancy rates and others have done either direct progesterone supplementation or luteal stimulation by hCG treatment in order to increase the pregnancy rates. However, these effects on pregnancy rates are inconsistent and also contradictory. 5.The asynchrony between donors or embryos and recipients may he a major cause of embryo death and low pregnancy rate and the sensitivity to uterine asynchyony differs in according to the quality and stages of embryos. 6.The extremes of poor or over nutrition during early pregnancy in the recipients are detrimental to the survival of embryos and the good body condition is required to prevent a reduejion of pregnancy rates. The uterine pathogens in embryonic mortality or fertility have been questioned but the infection of C.pyogenes and Campylobacter fetus is still important pathogens. 7.The heat stress during early pregnancy may reduce conceptus weight and possibly increase the embryonic mortality.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.30-37
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• 2017

This study was conducted to determine the effects of various growth substrates on the growth and flowering of hydroponically grown Freesia hybrid 'Gold Rich'. Perlite, peat moss and a perlite: peat moss mixture (1 : 1 ratio, v / v) were used as the growing media. The greatest plant height before flower bud differentiation was attained using mixed medium compared to the others. The type of medium used did not influence leaf number, mineral content or SPAD value in leaves. Flowering began at 137 days after planting in mixed medium, which was 13 days earlier than in perlite medium. The whole plant fresh weight was 21.3 g heavier in mixed medium than in perlite medium (40.9 g). A similar result was obtained for shoot length, with the highest value (96.6 cm) obtained in mixed medium, i.e., 20 cm higher than in perlite medium (76.6 cm). Floret number per plant was also the highest in mixed medium (14.4), i.e., 1.7 - times higher than in perlite medium. Therefore, among the substrates tested in this experiment, we recommend using mixed perlite: peat moss medium (1 : 1 ratio, v / v) for hydroponic culture of freesia, as the use of this medium improved the physical properties of the plants, producing the best results in terms of plant growth and cut-flower quality.

• Journal of Educational Research in Mathematics
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• v.9 no.1
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• pp.351-367
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• 1999

This study aims to study the discourses influencing high school students' concept and attitude toward mathematics, and to examine how gender differences concerning mathematical aptitude are created. This study is based on the results of previous two studies which suggested that mathematical competence differs not only according to gender, region and school year, but also even within the same gender. For this study, 12 students ranking in the top 10% at two co-ed high schools were interviewed to find out 1) what discourses are related to gender and mathematics, 2) in what way these discourses are formulated and gain currency, and 3) how they have affected students in general. Common notions concerning mathematics may be summed up as follows: 1) Most of the students believe that gender difference in mathematical aptitude results because biologically men tend to be strong in mathematics and analytical skills while women tend to have better linguistic ability. This concept can help male students' studying to have a greater learning toward mathematics. 2) A large number of the students believe that male students' studying method is based on comprehension whereas female students' method is based on retention, and hence the former group tends to be better at applying their learning than the latter group. This notion seres to encourage male students and discourage female students from tackling difficult mathematical problems. 3) Many students believe that, although female students may surpass their male counterparts in middle school or the first year of high school, they will eventually fall behind by the 3rd year. Despite research which shows that these common beliefs are not grounded in scientific proof, high-school girls, who may be strong in mathematics, lose self-confidence and feel a sense of crisis. The mechanisms which produce and reinforce such concepts as those mentioned above can be summarized as follows: 1) Regarding the choice of majors and future career paths, parents show different attitudes toward sons and daughters, and this tends to influence high-school girls and hinders them from entering mathematics-related fields. 2) Teachers with value systems based on stereo-typed gender roles affect students a great deal, and give different advice according to gender of their students, for selecting their major fields - for instance, whether to study the natural sciences as opposed to humanities. 3) This study indicates that peer-group behavior, of either support or exclusion, also reinforces the process of internalizing notions of gender difference related to mathematical aptitude. 4) The gender-based notion that men are naturally more inclined to have better mathematical ability has caused male students to choose the natural science subjects and female students to turn to the humanities. The discourses discussed above, propagated in schools and homes, and in the mass media, are continually reinforced along with general gender inequalities in the society at large.

• Journal of Embryo Transfer
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• v.27 no.4
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• pp.245-252
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• 2012

The purpose of the present study was to investigate the effect of IFN-${\tau}$ on prostaglandin synthesis, cyclooxygenase-2 (COX-2) gene expression in vitro and concentration of progesterone (P4) in endometrial cells. Epithelial and stromal cells cultured in vitro were isolated from bovine endometrium and stimulated with increasing doses of IFN-${\tau}$ (0, 0.02, 0.2 and 2 ug/ml). Human chorionic gonadotropin (hCG, 1.5 IU/ml) was used as a positive control. Prostaglandin $E_2$ and $F_{2{\alpha}}$ levels in the culture media were analyzed by enzyme immunoassays and total RNA was extracted from the cells for RT-PCR. P4 concentrations of blood samples were assayed by chemiluminescent immuno assays system. In epithelial cells, COX-2 gene expression was increased in the presence of IFN-${\tau}$ (p<0.05), but it was not significantly different in all groups of stromal cells except for 2 ug/ml IFN-${\tau}$ group (p<0.05). Although IFN-${\tau}$ did not affect $PGE_2$ and $PGF_{2{\alpha}}$ production in epithelial cells, it decreased $PGE_2$ and $PGF_{2{\alpha}}$ production significantly in stromal cells (p<0.05). In vivo experiment, blood concentration of P4 was significantly increased after addition of IFN-${\tau}$ (1 ug/ml). The results indicate that PG production was mediated by COX-2 expression in stromal cells but it was not affected in epithelial cells and this suggest that treatment of IFN-${\tau}$ could improve the implantation environment of uterine by maintenance of high P4 concentration.

• Journal of Korean Home Economics Education Association
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• v.19 no.3
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• pp.119-131
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• 2007

This study was to investigate the recognition level of food safety from high school students(264 male, 276 female) in Chuncheon area using questionnaires. The results of the survey are summarized as follows : Regarding the general consciousness of the conditions of food safety, the proportion of the students who worry about it is higher, while 40.0% respond they are not concerned with it. The information pertinent to food safety was usually acquired from the mass media. As a fundamental reason responsible for the food safety accidents, they pointed out deficient sense of responsibility of the personnels who produce, distribute, and sell food products. As the most problematic materials threatening food safety, they pointed out heavy metals(24.8%), and subsequent responses were environmental hormones(24.4%), food additives(17.0%). The foods, for which they are most concerned about residual pesticides, were vegetables and fruits. High proportion of the students perceived that agricultural products are not safe from residual pesticides, and most of the students(92.4%) thought that residual pesticides are bad for their health. The examination on the food safety influenced by heavy metals reveals that 87.4% of the students thought the materials do influence food safety. As the food kind that is likely to be most polluted by heavy metals, they pointed out fishery products. The highest concern about processed food stuffs was the food additives. Most of the students thought that the containers of processed foods may be toxical. 25% of the students are more seriously considering food safety when they buy foods. High proportion of the students who responded they confirm safety-related matters at the time of food purchase thought much of food safety, while high proportion of those who didn't confirm those matters lay a great importance on the taste.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.4
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• pp.237-243
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• 2002

Objective : The aim of this study was to evaluate the influence of different media on blastulation, mean cell number, percentage of inner cell mass (ICM) of total cells and ICM : trophectoderm (TE) ratio in mice. Materials and methods: A total 552 two cell embryos were retrieved from ICR female mice (4 weeks old) at 48 hr after hCG injection (mated just after hCG injection) and cultured in MEM (n=276) or TCM (n=276) supplemented with 20% hFF. The grading of blastocysts from zona-intact (ZiB) to -escape (hatching and hatched, ZeB) was performed at 72 hours after culture. Total, TE and ICM cell numbers were analyzed by differential staining of blastocyst. Statistical analysis was performed using t-test with SigmaPlot-2001. P-values < 0.05 were accepted as statistically significant. Results: The blastulation rate in MEM ($64.9{\pm}4.95%$) was significantly higher (p=0.0031) than that in TCM ($57.2{\pm}5.22%$). No differences were found in the number of ZiB and ZeB between MEM ($31.9{\pm}2.62$, $33.0{\pm}4.58%$), and TCM ($27.2{\pm}4.28$, $30.1{\pm}4.58%$). A total 314 blastocysts (MEM=166; TCM=148) were stained differentially. Mean cell number of blastocysts was significantly higher (p=0.0002) in TCM ($73.1{\pm}3.3$) than in MEM ($61.7{\pm}2.5$). Differential staining was successfully performed in 155 blastocysts (MEM=77; TCM=78). The percentage of ICM was significantly higher in MEM than in TCM ($20.9{\pm}1.3$ vs. $17.1{\pm}1.2%$, p=0.0281). The ICM : TE ratio was higher in TCM than in MEM (1 : $4.85{\pm}0.68$ vs. 1 : $3.78{\pm}0.78$, NS). Conclusion: These results show that MEM increase the blastocyst formation and percentage of ICM of total cells comparing with TCM in mice.

• Clinical and Experimental Reproductive Medicine
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• v.23 no.3
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• pp.333-339
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• 1996

Cumulus cells have possibly influence on fertilization of mouse oocytes and their subsequent development in vitro, because they readily produce lactate and pyruvate and can modify the concentration of substrates in the medium. In vitro fertilization of mouse oocytes with cumulus mass and their developments in five media which were differently composed in concentrations of glucose, lactate and pyruvate were observed. In the absence of glucose (CZ2 medium) decreased (p<0.01) the percentage of fertilization and embryos reaching the blastocyst stage. But, in the same concentration of glucose, lactate and pyruvate as mouse oviductal fluid with (MT1 medium) and without (MT2 medium) cumulus mass and modified CZB medium containing glucose (CZ1 medium) had no effects (p>0.05). These studies indicate that the adjustments of energy substrates concentration to the physiological level did not improve the fertilization of mouse oocytes with cumulus mass and their development in vitro, and the deletion of glucose showed adverse effects.

• Journal of Digital Contents Society
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• v.17 no.1
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• pp.1-10
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• 2016

< My Little Television > with the new format which extends one person media broadcasting to terrestrial broadcasting is creating a huge Topic Index. It started the first broadcast on April 2015 and has continued the number one in viewer rating in the same time. While viewers directly participate in the program through the Daum TV Pod and a host communicates with viewers in a real time, various opinions are being reflected on the program. While a lot of information about the program has spread through SNS, it has led to raising the viewer rating of program. Recently, the Topic Index on the program has been published through the big data analysis rather than the program evaluation only by the viewer rating. The research on the correlation between the program viewer rating and amount of buzz has increased. In this study, it has analyzed how the Topic Index which is an extended concept of the amount of buzz affects the viewer rating. Study results show that the Topic Index is analyzed to positively influence the viewer rating. It will give a lot of help in studying big data of SNS on the program.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.1-8
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• 2015

To identify the satisfaction level towards Gwangju regional TV broadcasting company's program, "I Like the Market" and the effect of market vitalization on the market merchants' public relationships, this study carried out survey targeting 256 merchants who are residing at the region. The research results demonstrated that the satisfaction level towards the program and market vitalization via the program exert significant effect on the public relationships. Specifically, satisfaction level towards the program for the vitalization of regional broadcast exert effect in the following order; devotion, relationship and reliability. Meanwhile, market vitalization exert positive effect on the relationship, reliability and devotion, in the order mentioned. This implies that the development of quality program for the regional residents plays an important role in the convergence of regional broadcast and in increasing broadcasting company's brand image. Accordingly, positive interaction via regional vitalization when it comes to the formation of regional broadcast program going forth may be needed for regional broadcast policies.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.2
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• pp.119-124
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• 2009

The aim of this study was to investigate the influence of ionic strength and iron impregnation on the attachment of Enterococcus faecalis to granular activated carbon (GAC). Column experiments were performed to examine bacterial adhesion to coconutbased GAC (c-GAC), iron-impregnated c-GAC (fc-GAC), acid-washed c-GAC (a-GAC) and iron-impregnated a-GAC (fa-GAC) under two different solution (NaCl 1, 10 mM) conditions. Results showed that bacterial mass recovery in c-GAC decreased from 77.3 to 61.6% while in a-GAC it decreased from 71.6 to 32.3% with increasing ionic strength from 1 to 10 mM. This indicates that bacterial attachment to GAC can be enhanced with increasing ionic strength. Results also showed that the mass recoveries in fc-GAC were 62.6% (1 mM) and 53.3% (10 mM) while they were 50.8% (1 mM) and 16.9%(10 mM) in fa-GAC, which were lower than those in c-GAC and a-GAC. This demonstrates that bacterial adhesion to GAC can be enhanced through iron impregnation. This study provides information regarding the effects of ionic strength and iron impregnation on bacterial attachment to GAC. Furthermore, this study will advance our knowledge of bacterial removal in surface-modified granular media.