• The Plant Pathology Journal
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• v.15 no.4
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• pp.158-161
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• 1999

We determined threshold environmental factros to initiate infection of pepper plants by Botrytis cinerea, a fungal pathogen of pepper gray mold, in two greenhouse conditions. A new efficient spore-trapping method was developed to estimate population density of airborne conidia in the greenhouses, and spore release was measured using a Kerssies' selective medium. At a given day, spores were released greater during daytime (mostly from 7:30 am to 10:30 am and at 4:30 pm) than nighttime. Diurnal and nocturnal temperatures in the greenhouse-1 were about $25^{\circ}$ and $17^{\circ}$,and relative humidity was 100% for prolonged 24 h due to rain on December 17, 1997. Population density of air-borne conidia was 3.0$\times$103 conidia/ $0.5\textrm{m}^3$ after two days, and the initial infection occurred in ten days. During the same period of time in the greenhouse-2, diurnal temperature was about $25^{\circ}$ and nocturnal temperature was below $15^{\circ}$, and population density of air-borne conidia was 104 conidia/ $0.5\textrm{m}^3$. Under these conditions, the initial infection started in three days. This indicates that the early infection occurs under which diurnal temperature is approximately $25^{\circ}$, nocturnal temperature is maintained below $15^{\circ}$, and population density of air-borne conidia is 104 conidia/ $0.5\textrm{m}^3$ at saturated relative humidity condition.

• Journal of Forest and Environmental Science
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• v.32 no.2
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• pp.129-139
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• 2016

Study was conducted to investigate tree diversity and its population and regeneration status in homegardens of upper Assam, Northeast India through field study by quadrat method. A total of 154 tree species have been recorded from 135 studied homegardens under 109 genera 53 families. Most of these species (79%) are indigenous to our country, while the rest (21%) arealiens (naturalized and cultivated exotics) by origin. Tree species richness per homegarden varies greatly in different homegardens and is ranged from 5 to 52 tree species with a mean of 22 ($SE{\pm}0.58$). A. malaccensis is the most dominant tree species in the studied homegardens contributed 34% of the total tree density of the documented trees. The tree density is much higher with 4,259 individuals $ha^{-1}$ but, basal area ($36.32m^2ha^{-1}$) is very less. Based on the number of individuals present, very rare species is accounted for 10%, rare species 39%, common species 19%, dominants 14% and predominant species 18% in the present study. The population density of 154 tree species is 4,259 (individuals $ha^{-1}$) for adults (>3.18 cm DBH), 5,902 (individuals $ha^{-1}$) for saplings and 38,164 (individuals $ha^{-1}$) for seedlings. The density of seedlings>saplings>adults represents good regeneration status of tree species in studied homegardens. The population structure study showed that about 8% tree species have good regeneration status, 9% have fair regeneration status, 48% have poor regeneration status and 34% tree species have no regeneration. Study suggests that research and development action is needed to stimulate regeneration of those tree species which having high importance value indices but showing poor or no regeneration. Based on present observation, it can be conclude that homegarden can emerge as an effective means for both economic well-being and biodiversity conservation in upper Assam, Northeast India.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.162-172
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• 2011

In this paper, simulation was used to determine accuracies of genomic breeding values for polygenic traits associated with many thousands of markers obtained from high density genome scans. The statistical approach was based upon stochastically simulating a pedigree with a specified base population and a specified set of population parameters including the effective and noneffective marker distances and generation time. For this population, marker and quantitative trait locus (QTL) genotypes were generated using either a single linkage group or multiple linkage group model. Single nucleotide polymorphism (SNP) was simulated for an entire bovine genome (except for the sex chromosome, n = 29) including linkage and recombination. Individuals drawn from the simulated population with specified marker and QTL genotypes were randomly mated to establish appropriate levels of linkage disequilibrium for ten generations. Phenotype and genomic SNP data sets were obtained from individuals starting after two generations. Genetic prediction was accomplished by statistically modeling the genomic relationship matrix and standard BLUP methods. The effect of the number of linkage groups was also investigated to determine its influence on the accuracy of breeding values for genomic selection. When using high density scan data (0.08 cM marker distance), accuracies of breeding values on juveniles were obtained of 0.60 and 0.82, for a low heritable trait (0.10) and high heritable trait (0.50), respectively, in the single linkage group model. Estimates of 0.38 and 0.60 were obtained for the same cases in the multiple linkage group models. Unexpectedly, use of BLUP regression methods across many chromosomes was found to give rise to reduced accuracy in breeding value determination. The reasons for this remain a target for further research, but the role of Mendelian sampling may play a fundamental role in producing this effect.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.33-38
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• 2002

The purpose of this study is to analysis of disposition distance of city park for the plan of suitable arrangement of city park based on the date examining Daegu Metropolitan City. The results of this study are as follows. 1) The result of analysis of population density as the case of districts, it appeared highly in city center area which Seo-Gu district and Nam-Gu district besides Jung-Gu district. However, it apperared in a low Buk-Gu district, Dong-Gu district and Salseong-Gun. 2) The result of analysis of population density as the case of regions, it appeared very highly Joukjun-Dong of Dalseo-Gu district($31,554per/km^2$), Naedang-Dong of Seo-Gu district($29,922per/km^2$). However it appeared in a low Yeuga-Maen($85per/km^2$) and Gachang-Maen($94per/km^2$) of Dalseong-Gun. The regions where the population density is high have very low green space and live a lot of low income layer. 3) The result of analysis of disposition distance, in the case of children park, it appeared an intensive distribution in Dongcheon-Dong and Guam-Dong of Buk-Gu district, Whanggm-Dong and Dusan-Dong of Suseong-Gu district, Sangin-Dong and Yeongsan-Dong and Walsung-Dong of Dalseo-Gu district. however, it appeared in a low in Jung-Gu district. The case of urban park of the neighboring area, it appeared the most in Dalseo-Gu district except 2 parks in Jung-Gu district, the case of urban park of the walking area, it appeared in equality in city. 4) In conclusion, the area have high population density and lots of low income layer, is in out of disposition distance should be considered in first for city park plan.

• Research in Plant Disease
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• v.6 no.1
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• pp.27-33
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• 2000

Population density of Plasmodiophora brassicae in soil of severely infested fields of Chinese cabbage decreased as soil depth increases. More than 97% of total population was found in surface soil (0-5cm depth), and a few resting spores of the pathogen were also detected in 40 cm-deep soil. the clubroot pathogen was evenly distributed over the surface soil without clustering around a Chinese cabbage plant. Density of P. brassicae in soil at 23 Chinese cabbage fields in Pyongchang, Kangwon province ranged widely from less than 10$^4$resting spores/g soil to above 10$\^$6/ resting spores/g soil. Few or none of P. brassicae was found in virgin soil without any cropping history, intermediate with 0.36-2.75$\times$10$^4$resting spores/g soil in fields of other crops but more than 10 times higher population was found in severely infected Chinese cabbage fields. Density of P. brassicae was highest in the fields of monocropping of crucifers with some exceptions, but was low in rotated fields with corn, rye, medicinal crops or other non-host vegetables. Pathoen density in soil was decreased rapidly when rye or medicinal crops were cultivated after Chinese cabbage, suggesting that survival of clubroot pathogen appears to be influenced greatly by cropping system. The improved method for detecting resting spores of P. brassicae in soil used in this study seemed to be adequate for estimating population density of P. brassicae in soil in aspects of clearer dyeing, increased detecting sensitivity, and simplicity in preparation.

• Korean journal of applied entomology
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• v.42 no.4
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• pp.367-381
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• 2003

Dispersal polymorphism in insects Is a kind of adaptive strategy of the life history together with the diapause, consisting of the “long-winged or alate forms” of migratory phase and the “short-winged or apterous forms” of stationary phase. Dispersal polymorphism is a polymorphism related with the flight capability, and has three categories ; the wing polymorphisms, flight muscle polymorphisms, and flight behavior variations. Phase variation is another type of dispersal polymorphism varying in morphology, physiology and wing forms in response to the density of the population. The dispersal migration is a very adaptive trait that enables a species to keep pace with the changing mosaic of its habitat, but requires some costs. In general, wing reduction has a positive effect on the reproductive potential such as earlier reproduction and larger fecundity The dispersal polymorphism is a kind of optimization in the evolutionary strategies of the life history in insects; a trade-off between the advantages and disadvantages of migration. Wing polymorphism is a phenotypically plastic trait. Wing form changes with the environmental conditions even though the species is the same. Various environmental factors have an effect on the dispersal polymorphisms. Density dependent dispersal polymorphism plays an important role In population dynamics, but it is not a simple function of the density; the individuals of a population may be different in response to the density resulting different outcomes in the population biology, and the detailed information on the genotypic variation of the individuals in the population is the fundamental importance in the prediction of the population performances in a given environment. In conclusion, the studies on the dispersal polymorphisms are a complicated field in relation with both physiology and ecology, and studies on the ecological and quantitative genetics have indeed contributed to understanding of its important nature. But the final factors of evolution; the mechanisms of natural selections, might be revealed through the studies on the population biology.

• Journal of the Korean Geographical Society
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• v.47 no.5
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• pp.755-774
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• 2012

The main objective of the study is to propose GIS-based methods to assess the population distribution criteria for undesirable facilities such as nuclear power plants. First of all, a review of the relevant criteria was conducted for the official documents compiled by such institutions as IAEA (International Atomic Energy Agency), U.S. NRC (Nuclear Regulatory Commission), and some national institutes including the Korea Institute of Nuclear Safety. It is informed from the review that the fundamental principle underlying the various criteria is to maximize the distance between a plant and the nearest population center. It is realized that two interrelated GIS-based techniques need to be devised to put the principle into practice; sophisticated ways of representing population distribution and identifying population centers. A dasymetric areal interpolation is proposed for the former and cell-based and area-based critical density methods are introduced. Grid-based population distributions at various spatial resolutions are created by means of the dasymetric areal interpolation. By applying the critical density methods to the gridded population distribution, some population centers satisfying the population size and density criteria can be identified. These methods were applied to the case of the Gori-1 nuclear power plant and their strengths and limitations were discussed. It was revealed that the assessment results could vary depending upon which method was employed and what values were chosen for various parameters. This study is expected to contribute to foster the applications of methods and techniques developed in geospatial analysis and modeling to the site selection and evaluation.

• Genomics & Informatics
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• v.7 no.3
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• pp.152-158
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• 2009

Although the genetic basis for bone mineral density (BMD) has been studied by many groups so far, genes responsible for this complex trait has not been completely revealed. In order to localize quantitative trait loci (QTLs) for BMD variation in Asian population, the study was designed using a group of Mongolian population, a genetically closed population with a homogeneous lifestyle. BMD was measured at the left and right wrists and ankles using DEXA in 1,082 participants from 142 families. Genotyping of 13 polymorphic microsatellite markers on chromosome 13 (average spacing 8-9 cM) and two-point and multipoint linkage analysis were performed. In two-point linkage analysis, we identified two markers, D13S175 (6.03 cM) and D13S265 (68.73 cM) that had LOD scores greater than 1 for left ankle (LOD=2.09, LOD=1.49, respectively). We also found a marker D13S175 (6.03 cM) with a high LOD for left wrist (LOD=1.49) and the markers D13S265 (68.73 cM) and D13S217 (17.21 cM) for the right wrist (LOD= 1.82, LOD= 1.62, respectively). Among these significant marker regions, only two regions at 17 cM (13p11) and 65 cM (13q21) for the right wrist overlapped with major QTLs reported in following multipoint linkage analysis (LOD= 1.7549, LOD=1.4462, respectively). This study provides the possible evidence of the presence of QTLs affecting right wrist BMD in Mongolian populations on 13p11 and 13q21. Modest evidence was also found for genes affecting left ankle and left wrist BMD on 13p13.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.146-152
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• 1982

Survey on potato parasitic nematodes has been undertaken in order to find distribution of the nemic fauna. 41 soil samples were taken from potato fields in Gyeongbug, Gyeongnam and Gangweon provinces. Twenty four species belonging to 16 different genera were identified. Potato cyst nematode, Globodera rostochiensis was not found in the areas. Potato-rot nematode, Ditylenchus destructor and stem nematode, Ditylenchus dipsaci were found from several potato fields and population density high and showed damage to the crops. Root-lesion nematode, Pratylenchus minyus, Pratylenchus penetrans, Pratytenchus thornei and Pratylenchus vulnus were found and their population of these four species were high depending on the fields. Root-knot nematode, Meloidogyne hapla and Meloidogyne incognita were found. M. hapla was found only in Gangweon province and the population density was high. M. incognita was found at Milyang in Gyeongnam province. Spiral nematode, Heticotylenchus digonichus, Helicotylenchus dihystera, Helicotylenchus pseudorobustus, Rotylenchus orientalis and Rotylenchus pini were found. Aphelenchoides saprophilus, Criconemoides informis, Ditylenchus destructor, D. dipsaci, Helicotylenchus digonichus, H. dihystera, Hemicriconemoides intermedius, Meloidogyne hapla, Psilenchus hilarulus, Pratylenchus minyus, and Xiphinema americanum were first found from potato fields in Korea.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.5-8
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• 2000

The population density of excited species in dc, rf and laser ablation plume plasmas has been measured using laser absorption spectroscopy. It was shown that, when the plasma was modulated by on and off with, the sensitivity and signal to noise (S/N) ratio became high. For example, the atomic O(3$^{5}$ S$^{o}$ $_2$) Population density, No* in $O_2$/He mixtures was obtained by the highest S/N ratio at a frequency of 2.7kHz. In a 20Torr room air, the lowest No* level to be detectable was shown to be an order of 10$^{7}$ cm$^{-3}$ . The population densities of resonance Ar(1S$_2$) and Xe(1S$_4$) levels were also measured in barrier discharges and laser ablation plasmas.