• Journal of Microbiology and Biotechnology
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• v.11 no.5
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• pp.788-797
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• 2001

The usefulness of three PCR methods were evaluated for the epidemiological typing of Staphylococcus aureus: an enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR), repetitive extragenic palindromic element PCR (REP-PCR), and 16S-23S intergenic spacer PCR (ITS-PCR). The analysis was performed using a collection of S. aureus strains comprised of 6 reference and 79 isolates from patients with various diseases. Among the 85 S. aureus strains tested, 6 references and 6 isolates were found to be susceptible to methicillin, whereas the remaining 73 isolates were resistant to it. PCR methods are of special concern, as conventional phenotypic methods are unable to clearly distinguish among methicillin-resistant S. aureus (MRSA) strains. The ability of the techniques to detect different unrelated types was found to be as follows: ERIC-PCR, 19 types; REP-PCR, 36 types; and ITS-PCR, 14 types. On the basis of combining the ERIC, REP, and ITS fingerprints, the 85 S. aureus strains were grouped into 56 genetic types (designated G1 to G56). The diversities for the 85 S. aureus strains, calculated according to Simpson\`s index, were 0.88 for an ERIC-PCR, 0.93 for a REP-PCR, and 0.48 for an ITS-PCR, and the diversity increased up to 0.97 when an ERIC-PCR and REP-PCR were combined. The above discrimination indices imply that the genetic heterogeneity of S. aureus strains is high. Accordingly, this study demonstrates that DNA sequences from highly conserved repeats of a genome, particularly a combination of ERIC sequences and REP elements, are a convenient and accurate tool for the subspecies-specific discrimination and epidemiologic tracking of S. aureus.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.178-186
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• 1991

This study was conducted to evaluate the major weeds occurred in direct seeded rice and their compition with rice, and to establish the effective weed control method. The important weeds occurring in dry direct seeded rice were Echinochloa crusgalli, Cyperus amuricus, Rorippa islandica, etc. Among them, Echinochloa crusgalli was the most dominant weed species. In view of the Simpson's dominance index, the maximum number of the weeds was observed at 30 days after seeding, showing 0.26, but decreased as the time passed. In other hand, Simpson's dominance index of weed dry weight increased from 0.09 at 15DAS(days after seeding) to 0.28 at 60DAS indicating that particular weed such as barnyardgrass was dominating the fields. The plant height and the tiller number of rice in the dry direct seeded rice were not greatly affected by the time and duration of competition with weeds, but rice yield was greatly influenced by them. The yield reduction was observed when compition between rice and weeds were initiated at 20 to 40 DAS till the harvesting time. The highest weed control efficacy was observed at the treatment of systematic herbicide application such as soil applied Butachlor followed by Mefenacet/Bensulfuron-methyl/Dymron at 30 DAS after seeding, and soil applied Dimepiperate/Bensulfuron-methyl mixture as a preemergence type gave also an excellent control.

• Korean Journal of Weed Science
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• v.9 no.1
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• pp.39-45
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• 1989

An experiment was conducted at the Yeongnam Crop Experiment Station for 4 years from 1985 to understand the effect of repeated use of same herbicide on weed growth. For this, the most common 6 herbicides, butachlor, bifenox, butachlor/pyrazolate, piperophos/dimethametryne, bentazon and propanil were used as single treatment or combination treatment. For non chemical plots, weed occurrence was rapidly increased with time in terms of number and weight. However no rice plot recorded the least increasing ratio. Similar trend was obtained at the herbicide plot even though the increasing ratio varied by herbicide properties. The least increasing ratio (1200 was recorded at the plot of butachlor/pyrazolate (5 days after transplanting, 5 DAT) followed by bentazon+propanil(25 DAT) while the greatest ratio (28%) was obtained from the plot of bifenox (5 DAT). In general, Scirpus hotarui, Eleocharis kuroguwai and Cyperus serotinus was gradually inereased with time by herbicide application, particularly at the butachlor/pyrazolate treatment. The community dominance and simpson index increased at the plot of bentazon and propanil due to increased of particular species while other herbicide plots exhibited reverse trend. Grain yield was curvilinearly decreased with weed weight for both times, 40 DAT and heading time eventhough the correlation coefficient of heading time was higher than 40 DAT.

• Current Research on Agriculture and Life Sciences
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• v.4
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• pp.22-26
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• 1986

This study was conducted to investigate weed population dynamic in orchard and to establish an appropriate application time for oxyfluorfen. 28 weed species including Persicaria hydropiper was observed to be problem weeds in orchard. P. hydropiper was on single dominant species which increased importance value of 13.7 on May 15 to 60.79 on August 10, followed by Calystegia hederacea, Alopecurus aequalis, Capsella bursa-pastoris, Roripa islandica, Echinochloa crus-galli, Potulaca olearcea, Elusin indica. Simpson's index increase from 0.11 on May 1 to 0.40 of August 10, indicating the dominance of specific weed species. The effective herbicide to control these weeds was oxyfluorfen at 5kg prod./ha applied at pereemergence treatment on March 25, showing more than 90% control for 120 days after application. Preemergence application of oxyfluorfen at 3kg prod./ha on March 25 followed by paraquat 3kg prod./ha applied on June 25 as the foliar application can maintain the clean orchard for a year, showing on of the promising and applicable control system. The most appropriate rate and time for oxyfluorfen seemed to be 5kg prod./ha applied on March 25.

• Journal of Forest and Environmental Science
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• v.37 no.4
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• pp.292-303
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• 2021

Studies that relate the structure of tropical regrowth vegetation to soil properties are generally lacking in the literature. This study proposes three indices for assessing the structural regeneration of secondary forests. They are: (1) the tree diameter class, (2) the plant life form and (3) the woody/herbaceous plants ratio indices. They were applied to assess the regeneration status of forest regrowth vegetation (aged 1-10 years), derived savanna regrowth vegetation in south western Nigeria, and to secondary forests in different stages of succession in Columbia and Venezuela, Bolivia, Mexico in South and Central America and semi-arid savanna in Ethiopia and seasonal deciduous forest successional stages in India. In all the cases, the indices increased with increasing age of regrowth vegetation and hence, with increasing structural complexity of regenerating vegetation. The tree diameter class index increased from 32.1% in a 9-year secondary forest to 69.0% in an 80-year-old secondary forest in Columbia and Venezuela and from 0.4% in a 1-year fallow to 20.9% in 10-year regrowth vegetation in southwestern Nigeria. In semi-arid savanna in northern Ethiopia, the woody/herbaceous plants ratio index increased from 18.1% in a 5-year protected grazing enclosure to 75.1% in 15-year protected enclosure, relative to the status of 20-year enclosure. The indices generally had correlations of 0.6-0.90 with species richness and Simpson's/Margalef's species diversity, implying that they are appropriate measures of ecosystem development over time. The proposed indices also had strong and positive correlations with soil organic carbon and nutrients. They are therefore, significant indicators of fertility status.

• Spatial Information Research
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• v.3 no.1
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• pp.47-53
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• 1995

The weed survey in lowland rice fields through Korea was conducted in 1992 to determine a change of the weed communities based on different regions, soil types, planting methods, and cultural practices. GIS was applied to identify a spatial analysis of predominant weed species in specific region. On behalf of vegetatine analysis such as absolute and relative density, absolute and relative frequency, importance value, and summed dominance ratio(SDR), there was highly dominant with a perennial weed species, Eleocharis kuroguwai Ohwi over whole country. However, in particular it was most predominant at southem area of Gyunggi province in Korea. Thus, rice farmers of this area have to introduce a specific comperhensive control strategy against this predominant weed species.

• Journal of the korean society of oceanography
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• v.37 no.1
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• pp.10-19
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• 2002

The detailed structure of a tidal front and its ebb-to flood variation in the main tidal channel of the Kyunggi Bay in the mid-west coast of Korea were investigated by analyzing CTD data and drifter trajectories collected in late July 1999. A typical tidal front was formed in water about 60 m deep at the mouth of the channel. Isotherms and isohalines in the upper layer above the seasonal pycnocline in the offshore stratified zone inclined upward to the sea surface to form a surface front, while those in the lower layer declined to the bottom front. The location of the front is consistent with $100 S^3/cm^2$ of the mixing index H/U defined by Simpson and Hunter (1974), where H is the water depth and U is the amplitude of tidal current. The potential energy anomaly in the frontal zone varied at an ebb-to flood tidal cycle, showing a minimum at slack water after ebb but a maximum at slack water after flood. This ebb-to flood variation in potential energy anomaly is not accounted for by the mixing index. We conclude that on- and offshore displacement of the water column by tidal advection is responsible for the ebb-to-flood variation in the frontal zone.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.8
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• pp.1285-1290
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• 2018

Objective: This study shows the effects of dietary fiber levels on cecal microbiota composition in geese at day 70 according to pyrosequencing of the 16S ribosomal RNA gene. Methods: A total of 468 1-day-old healthy male Yangzhou goslings with similar body weight were randomly divided into 3 groups with 6 replicates per group and 26 geese per replicate. Geese were fed diets with fiber levels of 2.5% (low fiber level diet, Group I) and 6.1% (Group III) during days 1-70, respectively, or 4.3% for days 1-28 and 6.1% for days 29-70 (Group II). Results: Low fiber level diet decreased body weight, average daily gain during, increased lower feed conversation rate of geese during day 1 to 70 (p<0.05). Low fiber level diet decreased the total operational taxonomic units, Chao1 index and Shannon index, whereas increased the Simpson index of cecal microbiota in geese at day 70. Low fiber level diet decreased the relative abundance of Bacteroidetes, Firmicutes, Bacteroides, and Paraprevotella in cecum of geese at day 70. The similarity of cecal microbiota between low fiber level diet group and other groups was smaller. Conclusion: This study indicates that the low fiber level diet decreased diversity of microbiota, and relative abundance of some beneficial microbiota in cecum of geese at day 70, implying that the low fiber level diet has negative influence on performance by altering the diversity and population of cecal microbiota in geese.

• Korean Journal of Weed Science
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• v.18 no.1
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• pp.63-68
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• 1998

This experiment was carried out to select some herbicides for edible wild greens, Album monanthum, Petasites japonicus, and Aster scaber. The herbicides tested were napropamide 21.8% EC, nitralin 50% WP, and pendimethalin 31.7% EC. Dorminant weeds in the field were Echinochloa crus-galli, Digitaria sanguinalis, Persicaria hydropiper, Chenopodium album, and Siegesbeckia pubescens. Simpson's index was calculated to 0.26~0.30, which showed that weed occurrence in the field was quite various. Control efficacy in the field treated with napropamide EC 872g(ai/ha)., nitralin WP 1,000g(ai/ha), and pendimethalin EC 634g(ai/ha) were 81.4%~85.6%, 79.4%~82.8%, and 86.8%~92.2%, respectively. The typical phytotoxic symptoms to herbicides were germination inhibition, growth retardation, and malformation.

• Journal of Forest and Environmental Science
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• v.30 no.3
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• pp.253-258
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• 2014

The study attempts to assess the status, distribution, conservation and use value of Medicinal and Aromatic Plant (MAPs) in the Sagarmatha National Park. Altogether 62 species of MAPs belonging to 47 genera and 33 families have been recorded in the study area. 10 species, belonging to 9 families are categorized as the potential species. Out of the these species, most potential in local but threatened species are Allium hypsistum Stearn, Cordyceps sinensis Sacc, Dactylorhiza hatagirea Soo, Nardostachys grandiflora DC, Aconitum orochryseum, Ephedra gerardiana Wall. Ex. Stapf, Swertia multicaulis D. Don, Picrorhiza scrophulariflora Penne, Rheum australe. D. Don, Malva verticillataL and Swertia pedicallata Benerji. By analysis of data using Simpson's diversity index (SI) and Shannon weaver function (H'), there was high diversity (more heterogeneous) MAPs species composition in the Manjo Gate to Large Dobhan. (0.98349). Less diversity (less heterogeneous) MAPs species composition was in Tyanboche to Pangoche (0.90419). Similarly, the Shannon weaver function shows that in plots laying out in Mongla to Phorche are evenly distributed than others However, higher MAPs species (i.e., 31) was found in the way of Manjo Gate to Larja Dobhan than others.