• Asian-Australasian Journal of Animal Sciences
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• v.25 no.6
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• pp.772-784
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• 2012

Marker-assisted gene pyramiding aims to produce individuals with superior economic traits according to the optimal breeding scheme which involves selecting a series of favorite target alleles after cross of base populations and pyramiding them into a single genotype. Inspired by the science of evolutionary computation, we used the metaphor of hill-climbing to model the dynamic behavior of gene pyramiding. In consideration of the traditional cross program of animals along with the features of animal segregating populations, four types of cross programs and two types of selection strategies for gene pyramiding are performed from a practical perspective. Two population cross for pyramiding two genes (denoted II), three population cascading cross for pyramiding three genes(denoted III), four population symmetry (denoted IIII-S) and cascading cross for pyramiding four genes (denoted IIII-C), and various schemes (denoted cross program-A-E) are designed for each cross program given different levels of initial favorite allele frequencies, base population sizes and trait heritabilities. The process of gene pyramiding breeding for various schemes are simulated and compared based on the population hamming distance, average superior genotype frequencies and average phenotypic values. By simulation, the results show that the larger base population size and the higher the initial favorite allele frequency the higher the efficiency of gene pyramiding. Parents cross order is shown to be the most important factor in a cascading cross, but has no significant influence on the symmetric cross. The results also show that genotypic selection strategy is superior to phenotypic selection in accelerating gene pyramiding. Moreover, the method and corresponding software was used to compare different cross schemes and selection strategies.

• Korean journal of applied entomology
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• v.28 no.3
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• pp.146-153
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• 1989

These studies were conducted to investigate development of chemical resistance in two-spotted spider mite (Tetranychus urticae Koch) trough single selection for a given period of time with five acaricides including carbophenothion and ethion of organo-phosphate compound, dicofol of organo-chlorine compound, cyhexatin of organo-tin compound, biphenthrin of synthetic pyrethroid compound; and to examine cross-resistance among the acaricides to the selected populations. The development of chemical resistance of two-spotted spider mite was greatly varied under single selection of the each five acaricides. The carbophenothion- and the ethion-populations at the 22nd and the 24th selected generations showed 156- and 64.1-fold resistant levels, respectively, as compared with the susceptible population. However, the dicofol population at the 28th selected generation exhibited 39.7-fold resistant level, and the biphenthrin population at the 24th selected generation revealed 25.2-fold resistant level, while the cyhexatin population at the 20th selected generation showed 13-fold resistant level. The carbophenothion-selected population showed high cross-resistance to ethion, and low cross-resistance to dicofol and biphenthrin. The ethion-selected population revealed also high cross-resistance to carbophenothion. The dicofol-or the biphenthrin-selected populations, however, exhibited moderate cross-resistance to carbophenothion and ethion. Meantime, the cyhexatin-selected population showed high cross-resistance to ethion and carbophenothion.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.243-249
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• 2008

In the previous study, 141 $BC_3F_2$ lines from a cross between the Oryza sativa cv. Milyang 23 and O. glaberrima were used to identify favorable wild QTL alleles for yield component traits. In this study, we carried out QTL analysis of four grain morphology as well as four yield component traits using 141 $BC_3F_5$ lines from the same cross and compared QTLs detected in two different generations. The mean number of O. glaberrima segments in the 141 $BC_3F_5$ lines ranged from 1 to 13 with 2.69 and 5.71 of the average means of homozygous and heterozygous segments, respectively. There was a three-fold difference in the number of QTLs detected for four traits commonly evaluated in two generations (seven QTLs in the $BC_3F_5$ vs 21 in the $BC_3F_2$ population). The percentages of the phenotypic variance explained by QTLs in the BC3F5 population were similar to or less than those in the $BC_3F_2$ population. This is probably due to the difference in the genetic composition of two populations and the environmental effects. The locations of the QTLs commonly detected in both generations were in good agreement except for one QTL for spikelets per panicle. The yield QTL, yd3 was colocalized with the spikelets per panicle, spp3. Yield increase at this locus is due to the increase in spikelets per panicle, because both traits were associated with increase in spikelets per panicle and yield due to the presence of an O. glaberrima allele. Clusters of QTLs for grain morphology traits were observed in two chromosome regions. One cluster harboring five QTLs near SSR markers RM106 and RM263 was detected on chromosome 2. This population would serve as a foundation for development of the introgression line population from a cross between Milyang 23 and O. glaberrima.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.2
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• pp.176-183
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• 2016

A study was conducted to assess the genetic diversity among Simmental Cross cattle in West Sumatra using microsatellite DNA markers. A total of 176 individual cattle blood samples was used for obtaining DNA samples. Twelve primers of microsatellite loci as recommended by FAO were used to identify the genetic diversity of the Simmental Cross cattle population. Multiplex DNA fragment analysis method was used for allele identification. All the microsatellite loci in this study were highly polymorphic and all of the identified alleles were able to classify the cattle population into several groups based on their genetic distance. The heterozygosity values of microsatellite loci in this study ranged from 0.556 to 0.782. The polymorphism information content (PIC) value of the 12 observed loci is high (PIC>0.5). The highest PIC value in the Simmental cattle population was 0.893 (locus TGLA53), while the lowest value was 0.529 (locus BM1818). Based on the genetic distance value, the subpopulation of the Simmental Cross-Agam and the Simmental Cross-Limapuluh Kota was exceptionally close to the Simmental Purebred thus indicating that a grading-up process has taken place with the Simmental Purebred. In view of the advantages possessed by the Simmental Cross cattle and the evaluation of the genetic diversity results, a number of subpopulations in this study can be considered as the initial (base) population for the Simmental Cross cattle breeding programs in West Sumatra, Indonesia.

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.10-15
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• 1995

Genetic characterization of Sri Lankan silkworm bivoltine population has not been at-tempted so far, since its sporadic introduction of bivoltine strains into the island, starting from the 1950's. Genetic structure of Sri Lankan population of mulberry silkworm Bombyx mori was investigated through estimation of general (GCA) and specific combining ability(SCA) and heritability(${h^2}_B$), on the economic quantitative characters from leading 8 inbreds and their 28 F1's in a half diallel cross, in an attempt to utilize the estimates in determination of future breeding methods and to predict the breeding value over the phenotypic value. It was found that the breeding population of the bivoltine silkworm in Sri Lanka has still maintained considerable amounts of additive gene action as well as nonadditive. For some time in the future, both breeding strategies of "selection without inbreeding" and also "inbreeding followed by crossing" should therefore be effective in genetic improvement of economic characters investigated. In addition, superior combiners in general and in specific F1′s were identified for each of 6 economic characters, to be immediately utilized in selection and also in cross breeding programs in Sri Lanka.

• Journal of Digital Convergence
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• v.6 no.2
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• pp.157-164
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• 2008

The current research utilized as its target population who are current users of web based information system in Korea. The research validated the dimensions by studying he constructs within the context of the web based information system user population. Correlation was found between Flow dimensions retained as components of a ross-Cultural Model. It was determined that these two dimensions-Intrinsic Interest and Control-are significant predictors of user success. The Cross-Cultural Model was validated, and it is therefore suggested as a basis for further study of user success indicators in he cross-cultural enterprise environment.

• Journal of Korean Society of Forest Science
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• v.63 no.1
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• pp.35-41
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• 1984

The attempts in this study were made to evaluate the variations in some needle characteristics of Pinus thunbergii between individual trees within population, between populations and between the hypothesized climatic districts. This species occurs naturally along the southern seacoast of Korea penninsula having a relatively mild maritime climate. The followings are the summarized results. The coefficients of variation of the needle volume and needle serration density were generally higher than those of any other traits studied. The significant differences of variations of needle cross section form factor between individual trees within population at 1% level, except only the Young gwang population, were affirmed. In the case of the eastern seacoast district, where the three study populations are included, significances of variation differences were calculated, 5% level at needle serration density and cross section area and 1% Level at needle volume. The very high significant difference of the variations of needle cross section form factor and needle longitudinal form factor were shown between population of the western seacoast district and 5% Level significance at needle volume in the southern seacoast district. The high significant differences between districts in respect to needle cross section form factor and cross section area were calculated. The Duncan's multiple range test showed the dissimilarity of the said characteristics between the hypothesized climatic districts. Summing up the results obtained so far, individual tree and population variations were markedly noted statistically and these may be extended to the silvicultural technology.

• The Plant Pathology Journal
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• v.19 no.1
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• pp.46-50
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• 2003

To evaluate the sensitivity of Monilinia fructicola to dicarboximides used in controlling brown rot of peach, the fungus was isolated from commercial peach orchards in Chochiwon (CH), Chongdo (CD), Gyeongsan (GY), and Youngduk (YO) in Korea. The population shift of dicarboximide-resistant isolates of M. fructicola was investigated for 3 years starting 1998. The frequency of procymidone-resistant isolates (PRI) was higher in CD and GY than in CH and YO. The frequency of PRI was higher in the mid season (July-August) than in the rest of the year. Cross-resistance rate of PRI to iprodione was over 87.8% during the investigation, and double-resistance to both procymidone and carbendazim was less than 10%. However, the rate of cross-resistant isolates to vinclozolin was low. In the orchards in GY and CH without any fungicide spray, the PRI population was persistent and did not vary for 3 years. The results suggest that dicarboximide resistance of M. fructicola could be a problem in controlling brown rot and blossom blight on peach trees because it may take a long time to recover the population with sensitive isolates even in the absence of these fungicides.

• Asia-Pacific Journal of Business
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• v.10 no.1
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• pp.13-23
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• 2019

Asian food and the Asian restaurant market have grown rapidly in the international market. It has become one of the major trends in the restaurant industry in the world. However, there has been little attempt to develop a scale for measuring customer's motivation to experience Asian restaurants, and cross-cultural approaches are very rare. From this point of view, this study examined an instrument to measure motivation to visit Asian restaurants developed by Jang and Kim (2015), which was originally developed based on UK customers, by applying the population from another cultural background, Thailand. A total of 308 valid responses were obtained in Thailand. CFA was performed with a Thai sample to test internal and external consistency of the scale with another population, and a comparison was made between UK and Thai customers.

• Journal of Preventive Medicine and Public Health
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• v.56 no.5
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• pp.397-406
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• 2023

Objectives: The purpose of this study was to determine factors associated with non-vaccination against coronavirus disease 2019 (COVID-19) among the Venezuelan immigrant population residing in Peru. Methods: A cross-sectional study was conducted using data obtained from the Second Survey of the Venezuelan Population Residing in Peru in 2022. The dependent variable was vaccination status against COVID-19. The independent variables included socio-demographic, economic, and migratory characteristics of the included population. Crude and adjusted generalized linear Poisson-family models were used to calculate prevalence ratios with 95% confidence intervals (CIs). Results: A total of 7739 Venezuelan migrants aged 18 years or older were included. The proportion of non-vaccination against COVID-19 was 5.7%. Regarding associated factors, unemployment (adjusted prevalence ratio [aPR], 1.31; 95% CI, 1.04 to 1.65) was linked to an increased likelihood of not being vaccinated against COVID-19. In contrast, women (aPR, 0.76; 95% CI, 0.61 to 0.95), possessing a migration permit (aPR, 0.41; 95% CI, 0.31 to 0.54), and having health insurance (aPR, 0.47; 95% CI, 0.27 to 0.81) were associated with a decreased likelihood of being unvaccinated. Conclusions: The primary governmental and non-governmental institutions responsible for supporting and protecting the Venezuelan migrant and refugee population should improve vaccination access by issuing migration permits and providing health insurance.