• Journal of the Korean Mathematical Society
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• v.58 no.1
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• pp.123-132
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• 2021

Let K be a number field and L a finite abelian extension of K. Let E be an elliptic curve defined over K. The restriction of scalars ResKLE decomposes (up to isogeny) into abelian varieties over K $$Res^L_KE{\sim}{\bigoplus_{F{\in}S}}A_F,$$ where S is the set of cyclic extensions of K in L. It is known that if L is a quadratic extension, then AL is the quadratic twist of E. In this paper, we consider the case that K is a number field containing a primitive third root of unity, $L=K({\sqrt[3]{D}})$ is the cyclic cubic extension of K for some D ∈ K×/(K×)3, E = Ea : y2 = x3 + a is an elliptic curve with j-invariant 0 defined over K, and EaD : y2 = x3 + aD2 is the cubic twist of Ea. In this case, we prove AL is isogenous over K to $E_a^D{\times}E_a^{D^2}$ and a property of the Selmer rank of AL, which is a cubic analogue of a theorem of Mazur and Rubin on quadratic twists.

• Korean Journal of Medicinal Crop Science
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• v.9 no.1
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• pp.76-82
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• 2001

This study was conducted to find out the optimum ranges of soil physical properties for wasabi growth by the relationship of soil physical properties and plant growth. Soil bulk density and hardness were higher in decomposition of granite and river sand than hydroball. This root distribution of surface layer was higher in decomposition of granite and river sand than hydroball. Growth characteristics and yield were higher in hydroball than decomposition of granite and river sand. In inlet site, the marketable rhizome weight in decompasition of granite, river sand, hydroball were 298kg/10a, 401kg/10a, 766kg/10a, respectively. But outlet, the weight in three soils were 251kg/10a, 256kg/10a, 633kg/10a, respectively.

• Research in Plant Disease
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• v.23 no.1
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• pp.65-68
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• 2017

Barley yellow mosaic virus (BaYMV), which is transmitted by the root-inhabiting protist Polymyxa graminis, causes a soil-borne disease. In this study, we detected BaYMV from soil using two-step nested polymerase chain reaction (PCR). Specific primers based on a coat protein region of BaYMV segment RNA1 were used in the first round of amplification. Based on the sequenced amplicon, an inner primer was designed for the second round of amplification. A PCR product of 372 bp exhibited 98%-100% nucleotide sequence identity with the coat protein region of BaYMV segment RNA1. In this study, we propose an easy method for the detection of BaYMV from soil, may considerably assist in accurate fungus-transmitted virus diagnosis and subsequent disease forecasting. This is the first report on the detection of BaYMV from soil.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.48-48
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• 2020

Fire blight, caused by Erwinia amylovora(Burrill), is a destructive disease of apple that damages blossoms, shoots, and woody plant organs. The fire blight disease is a worldwide problem for pome fruit growers because all popular apple cultivars are susceptible to the disease. Recently, fire blight of apple rootstocks has become a serious economic problem in high-density orchard systems in korea. The most commonly used dwarfing root stocks, M.9 and M.26, are highly susceptible to E. amylovora. The objective of the apple rootstock-breeding program has been to develop pomologically excellent rootstocks with resistance to abiotic and biotic stresses, including fire blight. Budagovsky 9 (B.9) apple rootstock is reported to be highly susceptible when inoculated with E. amylovora, although results from multiple trials showed that B.9 is resistant to rootstock blight infection in field plantings. So we tried to collect the apple rootstocks traits of fire blight resistance. The apple genotype Malus Robusta 5 (MR5) represents an ideal donor for fire blight resistance because it was described as resistant to all currently known European strains of the pathogen. The PCR for detecting the MR5 gene using the primers Md_MR5_FL_F/Md_MR5_FL_R. The results of these experiments confirmed some apple rootstocks traits of fire blight resistance showed the MR5. Furthermore, this gene is confirmed to be the resistance determinant of Mr5 as the transformed lines undergo the same gene-for-gene interaction in the host-pathogen relationship MR5-E. amylovora.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.19-19
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• 2020

The Cassava(Manihot esculenta Crantz) is a tropical root crop, originally from Amazonia, that provides the staple food of an estimated 800 million people worldwide. It belongs to the family Euphorbiaceae which also includes rubber (Hevea brasiliensis) and castor bean (Ricinus communis). Among tropical crops, rice, sugarcane, maize and cassava are the most important sources of calories for human consumption. Problems in the propagation of cassava are virus diseases and low rates of seed germination. So we tried to optimize protocols for mass production of somatic embryo amenable to large-scale vegetative propagation of Cassava. After in vitro eight-week culture of leaves of Cassava, the medium which contained the 2,4-D, BAP and IBA showed the highest callus induction rate, embryogenesis callus formation rate and somatic embryo formation in Cassava culture. In the medium with GA₃ and myo-inositol, shoots were most vigorously regenerated from somatic embryos of Cassava. Our experiments confirmed that in vitro growth and multiplication of plantlets could depend on its reaction to the different medium composition, and this micropropagation techniques could be a useful system for healthy and vigorous plant production.

• Kyungpook Mathematical Journal
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• v.54 no.4
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• pp.587-593
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• 2014

Let D be an integral domain with quotient field K, $\bar{D}$ denote the integral closure of D in K and * be a star-operation on D. In this paper, we study the *-Nagata ring of AP*MDs. More precisely, we show that D is an AP*MD and $D[X]{\subseteq}\bar{D}[X]$ is a root extension if and only if the *-Nagata ring $D[X]_{N_*}$ is an AB-domain, if and only if $D[X]_{N_*}$ is an AP-domain. We also prove that D is a P*MD if and only if D is an integrally closed AP*MD, if and only if D is a root closed AP*MD.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.3
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• pp.3-8
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• 2010

There are some efficient brute force algorithm for factorization. Fermat's factorization is one of the way of brute force attack. Fermat's method works best when there is factor near the square-root. This paper shows that why Fermat's method is effective and verify that there are only one answer. Because there are only one answer, we can start Fermat's factorization anywhere. Also, we convert from factorization to finding square number.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.5
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• pp.71-79
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• 2016

The effects of spot heating for growing the strawberry cultivated in a plastic greenhouse during the winter that were estimated in Nonsan strawberry experiment station located in Chungnam. The temperature of water for heating was controlled by a electric hot water boiler and kept at the range of $22{\sim}24^{\circ}C$. Heating pipes were set up in root zone for root zone heating and very close to crown for crown heating. Spot heating effects were estimated by applying spot heating system in three test factors of heating root zone, crown only and crown plus root zone. The material for crown heating pipe was white low density polyethylene and the nominal diameter of that pipe was 16 mm. The material for root zone heating pipe was flexible stainless steel and the nominal diameter of that pipe was 15A. The flow rate of heating water circulation was 480 L/h and water circulation lasted for all day long. Temperatures, harvest yield by test beds were surveyed from Nov. 10, 2013 to Apr. 29, 2014. The temperature of crown spot for crown heating bed was at the range of $13.0{\sim}17.0^{\circ}C$ during the night and that of crown spot in control bed was at the range of $8.0{\sim}14.0^{\circ}C$. Also, the temperature of root zone for root zone heating bed was at the range of $18{\sim}21.0^{\circ}C$ and that of root zone in control bed was at the range of $13.0{\sim}15.0^{\circ}C$. The cumulative yield growth rate in earlier harvest period (from Dec. 20 to Mar. 15) of crown heating bed was 43% compared with that of control bed and the cumulative yield of crown plus root zone heating bed was 39 % and that of root zone heating bed was 39 %.

• Journal of Microbiology and Biotechnology
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• v.22 no.1
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• pp.114-117
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• 2012

The biological control efficacy of a greenhouse soil bacterial mixture of Lactobacillus farraginis, Bacillus cereus, and Bacillus thuringiensis strains with antinematode activity was evaluated against the root-knot nematode Meloidogyne incognita. Two control groups planted in soil drenched with sterile distilled water or treated with the broad-spectrum carbamate pesticide carbofuran were used for comparison. The results suggest that the bacterial mixture is effective as a biocontrol agent against the root-knot nematode.

• Plant Resources
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• v.7 no.1
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• pp.29-35
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• 2004

Root chicory (Cichorium intybus L. var. sativus) is potential alternative medicinal and sugar crop which accumulates a high amount of linear polyfructan, inulin in its roots. A problem in root production is that over-wintered stock plants often flower. Once the plant becomes reproductive, stem elongation and root growth slows and floral buds arise from every node, rendering the plants useless for propagation. The objectives of this research was to examine the effectiveness of manipulating environmental factors containing photoperiod, temperature and number of leaf states. The experiment was performed in growth chamber to create two photoperiods (8 h, and 16 h) with three temperature regimes (5$^{\circ}C$/3$^{\circ}C$, 1$0^{\circ}C$/8$^{\circ}C$ and 15$^{\circ}C$/13$^{\circ}C$ day/night temperature) for a total of six treatments on three type of true-leaf stage of plant. Data of bolting rate, shoot and root length, shoot and fresh weight was invetigated in each treatments. This is the first report on changes in bolting rate and shoots and roots production during a whole growing season and differences in the effect of cold and photoperiod treatment depending on the true-leaf stage of plant.