• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.187-196
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• 2000

This paper describes a simple method that uses differences among Carlson's (1977) trophic state index (TSI) values based on total phosphorus (TP), chlorophyll a (CHL) and Secchi depth (SD) to draw inferences regarding the factors that are limiting to phytoplankton growth and the composition of lake seston. Examples are provided regarding seasonal and spatial patterns in a large subtropical lake (Lake Okeechobee, Florida, USA) and inter- and intra-lake variations from a multilake data set developed from published studies. Once an investigator has collected routine water quality data and established TSI values based on TP, CHL, and SD, a number of inferences can be made. Additional information can be provided where it also is possible to calculate a TSI based on total nitrogen (TN). Where TSI (CHL)<>TSI (SD), light attenuating particles are large (large filaments or colonies of algae), and the phytoplankton may be limited by zooplankton grazing. Other limiting conditions are inferred by different relationships between the TSI values. Results of this study indicate that the analysis is quite robust, and that it generally gives good agreement with conclusions based on more direct methods (e.g., nutrientaddition bioassays, zooplankton size data, zooplankton removal experiments). The TSI approach, when validated periodically with these more costly and time-intensive methods, provides an effective, low cost method for tracking long-term changes in pelagic structure and function with potential value in monitoring lake ecology and responses to management.

• Journal of Korea Water Resources Association
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• v.41 no.2
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• pp.163-172
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• 2008

Hydrologic regimes play a major role in determining the biotic composition, structure, and function of river ecosystem. In this study, hydrologic regimes were analyzed on down stream effects of the Young-Chun dam construction using the Indicators of Hydrologic Alterations(IHA). The analysis results were as follows ; (1) Monthly mean flows were decreased during drought and flood season on the pre and post dam, (2) Magnitude and Duration of Annual Exterm Conditions, annual minima 1-day means was $3.48m^3/sec$, $0.89m^3/sec$ and annual maxima 1-day mean was $833.1m^3/sec$, $672.1m^3/sec$ on the pre and post dam (3) Timing of Annual Exterm conditions, Julian date of the annual minima 1-day means was 180th(June) in the pre dam, 257th(September) in the post dam, Julian date of the annual maxima 1-day means was 209th(July) in the pre dam, 217th(August) in the post dam, (4) Frequency and Duration of High and Low Pulse, Low Puls counts and duration were 3 times and 23 days in the pre dam, High Pulse counts and duration were 4 times and 2 days in the pre dam. (5) Rate and Frequency of Water Condition Changes, rise rates was 39.27 %, 19.36 % and fall rates -15.85 %, -8.16 % in the pre and post dam, respectively (6) Coefficient of Variation, annual exteram water conditions were decreased from 0.9054 to 0.6314 and from 1.0440 to 0.9617, Timing of Annual Exterm conditions were incereased for minima flow from 0.269 to 0.282, for maxima form 0.069 to 0.153.

• Tuberculosis and Respiratory Diseases
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• v.56 no.4
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• pp.393-404
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• 2004

Background : Nucleic acid hybridization has become an essential technique in the development of our understanding of gene structure and function. The quantitative analysis of hybridization has been used in the measurement of genome complexity and gene copy number. The filter hybridization assay is rapid, sensitive and can be used to measure RNAs complementary to any cloned DNA sequence. Methods : The authors assessed the accuracy, linearity, correlation coefficient and specificity of the hybridization depending on the added dose(0, 1, 5, and $10{\mu}g$) of non-specific rat spleen RNA to hybridization of surfactant protein A mRNA. Filter hybridization assays were used to obtain the equation of standard curve and thereby to quantitate the mRNA quantitation. Results : 1. Standard curve equation of filter hybridization assay between counts per minute (X) and spleen RNA input (Y) was Y=0.13X-19.35. Correlation coefficient was 0.98. 2. Standard curve equation of filter hybridization assay between counts per minute (X) and surfactant protein A mRNA transcript input (Y) was Y=0.00066X-0.046. Correlation coefficient was 0.99. 3. Standard curve equation of filter hybridization assay between counts per minute (X) and surfactant protein A mRNA transcript input (Y) after the addition of $1{\mu}g$ spleen RNA was Y=0.00056X-0.051. Correlation coefficient was 0.99. 4. Standard curve equation of filter hybridization assay between counts per minute (X) and surfactant protein A mRNA transcript input (Y) after the addition of $5{\mu}g$ spleen RNA was Y=0.00065X-0.088. Correlation coefficient was 0.99. 5. Standard curve equation of filter hybridization assay between counts per minute (X) and surfactant protein A mRNA transcript input (Y) after the addition of $10{\mu}g$ spleen RNA was Y=0.00051X-0.10. Correlation coefficient was 0.99. Conclusions : Comparison of cpm/filter in a linear range allowed accurate and reproducible estimation of surfactant protein A mRNA copy number irrespective of the addition dosage of non-specific rat spleen RNA over the range $0-10{\mu}g$.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.4
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• pp.359-370
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• 2012

The endodontically treated tooth is generally restored with post and core, owing to the brittle and the loss of large amount of tooth structure. The purpose of this study was to evaluate the clinical status of fixed prostheses to improve the quality of dental care. In order to assess the clinical status of fixed prostheses, a total of 101 individuals (aged 30-89, 66 women and 35 men loaded with 125 fixed prostheses) who treated in the Department of Prosthodontics, Pusan National University Dental Hospital, between January 1990 to December 2005 were examined. The results of this study were as follows: 1. Length of service of fixed prostheses was $9.7{\pm}3.4$ years (mean), 11.1 years (median). 2. Age and sex of patient was found to have no statistically significant influence on longevity of fixed prostheses (P>.05). 3. Location of fixed prostheses was found to have statistically significant influence on longevity of fixed prostheses (P<.05). The longevity of fixed prostheses was low in anterio-posterior combination region (median:9.2 years). 4. Longevity of fixed prostheses made of base metal ceramic(median:12.0 years) and noble metal ceramic (median:11.3 years) is long (P<.05). 5. Number of units in fixed prostheses was found to have no statistically significant influence on longevity of fixed prostheses (P>.05). 6. Condition of opposing dentition was found to have no statistically significant influence on longevity of fixed prostheses (P>.05). 7. Dental caries, periapical disease, tooth fracture were frequent complications. In 51.9% of the cases, abutment state after removing fixed prostheses was needed to be extracted.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.2
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• pp.109-120
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• 2017

A discounted cost model for preventive maintenance of armor units of rubble-mound breakwaters is mathematically derived by combining the deterioration model based on a discrete-time stochastic process of shock occurrence with the cost model of renewal process together. The discounted cost model of condition-based maintenance proposed in this paper can take into account the nonlinearity of cumulative damage process as well as the discounting effect of cost. By comparing the present results with the previous other results, the verification is carried out satisfactorily. In addition, it is known from the sensitivity analysis on variables related to the model that the more often preventive maintenance should be implemented, the more crucial the level of importance of system is. However, the tendency is shown in reverse as the interest rate is increased. Meanwhile, the present model has been applied to the armor units of rubble-mound breakwaters. The parameters of damage intensity function have been estimated through the time-dependent prediction of the expected cumulative damage level obtained from the sample path method. In particular, it is confirmed that the shock occurrences can be considered to be a discrete-time stochastic process by investigating the effects of uncertainty of the shock occurrences on the expected cumulative damage level with homogeneous Poisson process and doubly stochastic Poisson process that are the continuous-time stochastic processes. It can be also seen that the stochastic process of cumulative damage would depend directly on the design conditions, thus the preventive maintenance would be varied due to those. Finally, the optimal periods and scale for the preventive maintenance of armor units of rubble-mound breakwaters can be quantitatively determined with the failure limits, the levels of importance of structure, and the interest rates.

• Korean Journal of Environment and Ecology
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• v.32 no.6
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• pp.603-617
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• 2018

This study surveyed the diversity and community characteristics of benthic macroinvertebrates and freshwater fish, which are the main animal classifications in a hydro ecosystem, from May to September 2017 in the western plains of the Demilitarized Zone (DMZ). The results showed a total of 125 species of benthic macroinvertebrates belonging to 66 families, 19 orders, and four phyla in the streams and wetlands. Among benthic macroinvertebrates, Coleoptera (27 spp.: 21.60%) was the largest group in terms of species richness followed by Odonata (26 spp.: 20.80%), non-Insecta (22 spp.: 17.60%), and Hemiptera (11 spp.: 8.80%) occupying in the lentic area. Of the feeding function groups (FFGs), predators (51 spp.: 56.67%) showed a relatively larger presence, indicating the dominance of hygrophilous invertebrates that usually inhabit the freshwater wetlands or ponds. Of the habitat oriented groups (HOGs), climbers (33 spp.: 24.44%) and burrowers (17 spp.: 12.59%) were the dominant groups. This observation is typical in a slow flowing habitat and can lead to the disturbance of the ecosystem due to cannibalism among predators. Cannibalism can be caused by stress induced by various population and environmental factors. For the ecosystem services benchmark (ESB) value, site 13 appeared to be the highest with 82 marks while other sites showed relatively lower rates and indices (III water quality class with ${\alpha}$-mesosaprobic). The analysis result of stability factors showed that almost all sites were evaluated to be the I characteristic group with high resilience and resistance or the III characteristic group that was sensitive to environmental disturbance and formed uneven and unstable communities. Of the freshwater fishes, 46 species (3,405 individuals) belonging to 39 families and 18 orders were identified in all the investigated sites. Among them, Cyprinidae (30 spp.: 65.2%) was the largest group, and Zacco koreanus was identified as the dominant species (728 individuals, 21.4%). The survey of freshwater fish communities found both stable communities (sites 7 and 13) with low dominant index (0.39) and high diversity index (2.29) and unstable communities (sites 2, 3, 8, and 10) in opposite tendency. This survey found five Korean endemic species, 17 species belonging to the export controlled species, two endangered species level II (Lethocerus deyrollei and Cybister chinensis), and rare species (Dytiscus marginalis czerskii) among benthic macroinvertebrates. The survey also found an invasive species, Ampullarius insularus, which was distributed throughout the whole area and thus can continuously disturb the ecosystem in the western plain area in the DMZ. Of freshwater fish, one natural monument (Hemibarbus mylodon) and three endangered species level II (Acheilognathus signifer, Gobiobotia macrocephalus, and G. brevibarba) were observed. The survey also found four introduced species (Pomacea canaliculate, Carassius cuvieri, Lepomis macrochirus, Micropterus salmoides) in the western DMZ area, indicating the need for the protection and conservation measures.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.717-731
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• 2021

We analyzed the characteristics of the habitat environment for the Seonam study area in Ulsan, the southern shore of the East Sea using bathymetry and seafloor environment data. The depth of the study area ranges from about 0 m to 23 m. In the west of the study area, the water depth is shallow with a gentle slope, and the water depth becomes deeper with a steep slope in the east. Due to the right-lateral strike-slip faults located in the continental margin of the East Sea, the fracture surfaces of the seabed rocks are mainly in the N-S direction, which is similar to the direction of the strike faults. Three seafloor types (conglomeratic-grained sandy, coasre-graiend sandy, fine-grained sandy) and rocky bottom area have been classified according to the analyses of the bathymerty, seafloor image, and surface sediment data. The rocky bottom areas are mainly distributed around Seaoam and in the northern and southern coastal area. But the intermediate zone between Seonam and coastal area has no rocky bottom. This intermediate area is expected to have active sedimentation as seawater way. The sandy sediments are widely distributed throughout the study area. Underwater images and UAV images show that Cnidarians, Brachiopods, Mollusks are mostly dominant in the shallow habitat and various Nacellidae, Mytilidae live on the intertidal zone around Seonam. Annelida and Arthropod are dominant in the sandy sediments. The distribution of marine organism in the study area might be greatly influenced by the seafloor type, the composition and particle size distribution of the seafloor sediments. The analysis of habitat environment mapping with bathymetry, seafloor data and underwater images is supposed to contribute to the study of the structure and function of marine ecosystem.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.2
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• pp.111-123
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• 2022

Carbonate green rust (CGR) and sulfate green rust (SGR) commonly occur in nature. In this study, CGR and SGR were synthesized through co-precipitation, and their formation mechanisms and physicochemical properties were investigated. X-ray diffraction (XRD) and Rietveld refinement showed both CGR and SGR with layered double hydroxide structure were successfully synthesized without any secondary phases under each synthetic condition. Refined structural parameters (unit cell) for two green rusts were a (=b) = 3.17 Å and c = 22.52 Å for CGR and a (=b) = 5.50 Å and c = 10.97 Å for SGR with the crystallite size 57.8 nm in diameter from (003) reflection and 40.1 nm from (001) reflections, respectively. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) results showed that both CGR and SGR had typical hexagonal plate-like crystal morphologies but their chemical composition is different in the content of C and S. In addition, Fourier transform infrared (FT-IR) spectroscopy analysis revealed that carbonate (CO₃^2-) and sulfate (SO₄^2-) molecules were occupied as interlayer anions of CGR and SGR, respectively. These SEM/EDS and FT-IR results were in good agreement with XRD results. Changes in the solution chemistry (i.e., pH, Eh and residual iron concentrations (Fe(II):Fe(III)) of the mixed solution) were observed as a function of the injection time of hydroxyl ion (OH^-) into the iron solution. Three different stages were observed in the formation of both CGR and SGR; precursor, intermediator, and green rust in the formation of both CGR and SGR. This study provides co-precipitation methods for CGR and SGR in a way of the stable synthesis. In addition, our findings for the formation mechanisms of the two green rusts and their physicochemical properties will provide crucial information with researches and industrials in utilizing green rust.

• Journal of The Korean Association For Science Education
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• v.43 no.1
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• pp.49-57
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• 2023

The purpose of this study is to analyze the school biology curriculum of the Royal Society of Biology (RSB) for school biology education in the United Kingdom (UK), and to examine the implications for Korean school biology education. The RSB school biology curriculum consists of three dimensions (the practices of biology, the concepts of biology, and the application of biology) and seven big questions. The contents of RSB school biology curriculum are structured according to age, 5-11, 11-16, and 16-19. The practices of biology of the UK RSB school biology curriculum emphasize biology activities should be linked to other communities and communicated and shared through evidence-based discussions. The concepts of biology dimension of the UK RSB school biology curriculum systematized the contents to be detailed considering school-level and ages with 5-7, 7-11, 11-14, 14-16, and 16-19 years old. The UK RSB biology curriculum is composed of human health, biological structure and function, biological growth and reproduction, and biological coexistence, showing a significant difference from Korean national curriculum when comparing the content elements with the core concepts of biology. In terms of the application of biology of the RSB school biology curriculum, three themes were commonly applied to all students, regardless of school level or age, such as development of application methods to promote health and environmental welfare, evaluation of the impact and application of biology knowledge. However, the content elements of the three themes were systematized according to the ages of 5-11, 11-16, and 16-19 years old. It is necessary to reorganize the contents of biology curriculum in Korea by referring to the content system of the UK RSB biology curriculum and to research ways to strengthen connectivity according to age or school level as well as dimensions and big questions.

• The Journal of the Convergence on Culture Technology
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• v.10 no.5
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• pp.367-372
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• 2024

It was intended to explore the relationship between motivation for participation in hair education, program satisfaction, and lifelong learning happiness index for adult learners at the Lifelong Education Center, and to provide basic data for revitalizing lifelong education programs. Today, universities have conditions as a comprehensive educational institution with practicality that can meet various and high-quality lifelong educational needs. The university-affiliated Lifelong Education Center plays a role in ensuring the right to learn for all citizens as well as fulfilling the social service function and greatly expanding educational opportunities, which is one of the essential functions of universities, by making good use of the excellent transfer material resources of universities. Adults should now seek professional self-identity through retraining, and respond flexibly to various social situations such as increasing roles, expanding responsibility, and uncertainty in the job and employment structure toward professional socialization in the professional world The subject of the study was to collect data by distributing 90 questionnaires to adult learner hair education subjects in G area, and 85 copies were finally used for SPSS 26.0 for Windows analysis, excluding questionnaires with insufficient responses. The survey period was from November 1 to December 27, 2023. First, it was found that adult learners' motivation to participate in hair education has an effect on the lifelong learning happiness index. Second, it was found that adult learners' satisfaction with the program of hair care workers has an effect on the lifelong learning happiness index. Through this study, it is judged that it is necessary to understand what can maximize the high lifelong learning happiness index, and to meet the learning needs of modern people living in the age of 100, increase their potential, help them design a second life, contribute to self-realization and society, and help them have steady, self-directed lifelong learning opportunities.