• Title/Summary/Keyword: Longitudinal study

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Ecological Health Assessments and Water Quality Patterns in Youdeung Stream (유등천에서의 생태학적 건강도 평가 및 수질양상)

  • Lee, Jae-Yon;Jang, Ha-Na;An, Kwang-Guk
    • Korean Journal of Ecology and Environment
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    • v.38 no.3 s.113
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    • pp.341-351
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    • 2005
  • Ecological stream health, based on the index of biological integrity (IBI) , was evaluated at five sampling locations of Youdeung Stream during August-October 2004. For the study, we also analyzed spatial and temporal patterns of conventional water quality over tine period of 1995 ${\sim}$ 2004, using the water chemistry dataset, obtained from the Ministry of Environment, Korea. The water quality parameters used here were conductivity, total suspended solids (TSS), biochemical oxygen demand $(BOD_5)$, chemical oxygen demand $(COD_{mn})$, total nitrogen (TN), and total phosphorus (TP). The multi-metric model values averaged 27.8 in the stream and ranged 24 ${\sim}$ 32. The health condition was judged as 'Fair' to 'Poor' conditions, according to the stream health criteria of US EPA (1993). Longitudinal variation occurred from the upstream to downstream reach; largest differences in all water quality variables occurred between Site 5 and the other sites. This was mainly attributed to the impacts of wastewater treatment plants near the locations. Also, relative proportions of tolerance and omnivore species increased in downstream reaches. The model values, however, did not match the values, based on water quality parameters. We assume that this may be associated with primarily reduced water volumn during dry season in the stream along with modified physical habitat conditions.

A Diagnosis of Ecological Health Using a Physical Habitat Assessment and Multimetric Fish Model in Daejeon Stream (물리적 서식지평가기법 및 어류 다변수 평가모델에 의거한 대전천의 생태학적 건강도 진단)

  • Kim, Ja-Hyun;An, Kwang-Guk
    • Korean Journal of Ecology and Environment
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    • v.38 no.3 s.113
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    • pp.361-371
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    • 2005
  • The objective of study was to diagnose integrative ecological health of Daejeon Stream, one of the tributaries of Guem River, during May 2004 ${\sim}$ April 2005. The research approach was primarily based on a Qualitative Habitat Evaluation Index (QHEI) and the Index of Biological Integrity (IBI) using fish assemblage. These outcomes were compared with conventional chemical dataset. For the experiment, four sampling sites were chosen from Daejeon Stream and long-term water quality data during 1995 ${\sim}$ 2004 (obtained from the Ministry of Environment) were analyzed in the spatial and temporal aspects. For the biological health assessment, we developed a stream health assessment model (SHA model) far regional applications. We found that current water quality conditions, based on the COD, BOD, TN and TP, were enhanced by 1.6 ${\sim}$ 5.3 fold over the period of 1995 ${\sim}$ 2004 and that the parameters showed a typical longitudinal decline from the upstream to downstream reach. The differences of water quality between the two reaches were more than 4.4 times, indicating a large spatial variations within the stream. The health conditions, based on the SHA model, averaged 23 and varied from 20 to 26 depending on the sampling stations. Values of the QHEI varied from 39 (Poor condition) to 124 (Cood condition)and values of QHEI in the reach of S2 ${\sim}$ S4 had significantly lower than in the headwater site (S1). Also, biological stream health, based on the criteria of US EPA (1993), was judged as 'Poor condition', in the S4 where TN, TP, BOD and COD were highest. In the meantime, maximum value of SHA (26) was found in the upstream reach (S1) where the water quality and QHEI were best. We also found that compositions of sensitive species showed a linear function with water quality conditions and this pattern was evident in the tolerant species. Thus, the biological stream health, based on the SHA model, matched well water chemistry. Overall outcomes suggest that the biological health impact was a function of chemical degradation and physical habitat quality in the stream.

Spatial Distribution and Dynamics of Vegetation on a Gravel Bar: Case Study in the Bangtae Stream (자갈 하중주에서 식생의 공간 분포 및 동태: 방태천의 사례)

  • Pee, Jung-Hun;Kim, Hye-Soo;Kim, Gyung-Soon;Oh, Woo-Seok;Koo, Bon-Yoel;Lee, Chang-Seok
    • Korean Journal of Ecology and Environment
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    • v.46 no.2
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    • pp.215-224
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    • 2013
  • We clarified the background for establishment of vegetation by comparing the spatial distribution maps of vegetation and substrate on a gravel bar in the Bangtae stream located on Inje-gun of Gangwon-do, the central eastern Korea. The total vegetation coverage was higher in the interior and lower in the marginal parts of the gravel bar. Spatial distribution of vegetation on the longitudinal section of the gravel bar tended to be arranged in the order of shrub, subtree, and tree dominated vegetation types from the front (upstream) toward the rear (downstream) parts. Coverage of the herbaceous plants was higher in the central and rear parts and lower in the front and right parts of the gravel bar. Vegetation height was higher in the rear part and became lowered as move toward the front part. Substrate was distributed in the order of boulder, gravel, sand, and boulder from the front toward the rear parts. Ordination of stands based on vegetation data was arranged in the order of annual plant, perennial herb, shrub, and tree dominated vegetation as move from the right to the left parts on the axis I. Species richness was higher in the order of Pinus densiflora community, Phragmites japonica community, Salix gracilistyla community, Fraxinus rhynchophylla community, annual plant dominated vegetation, and Prunus padus for. padus community based on the species rank-abundance curve. The order based on the Shannon's index was some different; diversity of Phragmites japonica community and Salix gracilistyla community, which showed higher dominance degree, were low differently from species richness. In conclusion, it was evaluated that the gravel bar newly established toward the upstream and vegetation dynamics of the gravel bar seemed to follow ecosystem mechanisms of succession. As were shown in the above results, the Bangtae stream corresponded to the upstream and thereby particle size of substrate was big. Therefore, they move by rolling and are accumulated for the upstream. Vegetation types were arranged in the order of woodland, shrub-land and grassland from the rear toward the front parts of the gravel bar and thereby reflected the formation process of the bar. However, the gravel bar is disturbed frequently by not only the running water but also the suspended sand as the dynamic space. Such disturbances cause habitat diversity and consequently led to high biodiversity.

Geochemical Exploration for Tri Le REE Occurrence in Nghe An Province within Northern Vietnam (베트남 북부 네안성 칠레 희토류 산출지의 지구화학탐사)

  • Heo, Chul-Ho;Ho, Tien Chung;Lee, Jae-Ho
    • Economic and Environmental Geology
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    • v.47 no.2
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    • pp.147-168
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    • 2014
  • The soil geochemical exploration was carried out targeting around Tri Le area far from about 30 km with northwestern direction from Que Phong within Nghe An province. The interval of sampling are horizontal 200 m interval with 23 line and longitudinal 300 m with 10 line, resulting in 228 soil samples. Based on the result of the soil geochemical exploration, the detailed pitting survey was carried out targeting the grid point with high TREO content, resulting in 75 soil samples within 7 pits. The geology of survey area are consisted of Ban Chieng biotite granite complex and granitic gneiss intruding Ban Khang formation comprising of quartz schist and marble. Main mineralization in the study area have the characteristics of occurrence with tin, ruby and REE-bearing monazite and xenotime to be thought as occurring at the alteration zone of granite complex. In order to elucidate the source rock of monazite and xenotime confirmed from heavy sand, soil geochemical exploration was carried out. As a analysis result with ICP-MS on the soil samples from the soil geochemical exploration, total REE oxide content of background amount to about 2 times of crustal abundance, enriching the heavy rare earth(about 2 times) and light rare earth(about 1.5 times). As a analysis result with ICP-MS on the soil samples from the soil detailed pit survey, we only identified outcrop considering as economic weathered granite body at the grid point 1-10 pit among 7 pits. As a synthetic consideration on the soil geochemical exploration and detailed pit survey, we tentatively designated Tri Le area as no promising target for REE. In 2014, we have the plan to carry out the soil geochemical exploration targeting the extended economic REE ore body in Quy Chau as project area from 2011 to 2012.

Macro-environmental Drivers and Technological Evolution of Complex Product System: Evidence from Nuclear Power Plant (거시환경요인과 복합제품시스템의 기술진화: 원자력 발전 플랜트의 사례를 중심으로)

  • Kwak, Kiho;Kim, Wonjoon;Kim, Minki;Cho, Chang Yeon
    • Journal of Technology Innovation
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    • v.25 no.2
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    • pp.89-125
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    • 2017
  • Complex product systems (CoPs) is a engineering-intensive products with high-ended design technology, which are closely linked with national economic growth and development of social infrastructures. Accordingly, in order to understand the technological evolution of CoPs, it is necessary to identify the macro-environmental drivers surrounding the CoPs and their impact on the technological evolution of the CoPS. Therefore, we investigate the effect of policy, economic and social drivers on the technological evolution of CoPS by implementing the longitudinal case study on nuclear power plant during the periods between 1950 and 2010s. Based on the analysis of various sources of secondary data and primary data through interviews, we found that the technological evolution of nuclear power plant is progressed as "Phase 1: Application research for peaceful utilization of nuclear energy" between 1950s and 1960s, "Phase 2: The first renaissance of nuclear energy" during 1970s, "Phase 3: Enhancement of safety and the catch-up of latecomers in nuclear energy" between 1990s and 2000s, and "Phase 4: Top prioritization of safety and the development of next generation reactors for the second renaissance of nuclear energy" since 2010s. We also found that various kinds of policy, economic and social drivers, such as energy policy, investment in technology development, economic growth and energy demand, social acceptability and environmental concern, have affected the technology evolution of nuclear power plant at each phase. We emphasize the role of macroenvironmental drivers in the technological evolution of CoPS. We also suggest that countries that endeavor to develop CoPs need to utilize those drivers for enhancing competitiveness and sustaining leadership.

SEMI-LONGITUDINAL STUDY ON GROWTH AND DEVELOPMENT OF CHILDREN AGED 6 TO 17 -Part III : GROWTH CHANGE OF CRANIOFACIAL HARD TISSUE (한국인 6-17세 아동의 성장과 발육에 관한 준종단적 연구 -제 3 세부 과제 : 두개 및 안면 경조직의 성장변화)

  • Hwang, Chung-Ju;Kil, Jea-Kyoung;Lim, Seon-A
    • The korean journal of orthodontics
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    • v.26 no.5 s.58
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    • pp.469-485
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    • 1996
  • Orthodontic patients are individuals that grow and develop ; therefore selection of the proper time for orthodontic treatment is considered to be one of most difficult and yet difficult factor. Since the development of cephalometric X-ray, amount and Pattern of craniofacial growth change with aging could be predicted and be came useful in the process of orthodontic treatment. The relationship between the mean values of cephalometric measurements and body height and weight was studied among the groups(boys and girls) of Korean children from the ages 6-years to 17-years. 409 boys and 437 girls with no abnormality in growth and development and no history of orthodontic treatment from the ages of 6 years to 17 years were chosen as subjects Cephaloment X-ray were taken for 3 years and hard tissue analysis based on Burstone's COGS, which was devided into measurements of 6 parts(Cranial base, Maxillar and Mandible, Dental measurements). The relationship between craniofacial growth and height & weight was studied. The following conclusions were obtained : 1. The maximum growth in the measurements of cranial base, N-Ar(FH), N-Ba(FH) corresponded with the age with the maximum increase in body height & weight in both boys and girls. 2. Genial angle gradually decreased with aging in both boys and girls. 3. N-ANS(L) showed greater amount of growth than ANS-Ne(L), and this had greater influence on facial profile. 4. N-A-$Pog^{\circ}$ decreased with aging, and mandibular growth exceeded maxillary growth in amount and rate. 5. Length of Y-axis Increased, but Y-axis to FH plane remained constant. This show that mandible grows at a constant angulation to cranial base. 6. As permanent teeth erupt, interincisal angle deceased.

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Development of Two-dimensional Prompt-gamma Measurement System for Verification of Proton Dose Distribution (이차원 양성자 선량 분포 확인을 위한 즉발감마선 이차원분포 측정 장치 개발)

  • Park, Jong Hoon;Lee, Han Rim;Kim, Chan Hyeong;Kim, Sung Hun;Kim, Seonghoon;Lee, Se Byeong
    • Progress in Medical Physics
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    • v.26 no.1
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    • pp.42-51
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    • 2015
  • In proton therapy, verification of proton dose distribution is important to treat cancer precisely and to enhance patients' safety. To verify proton dose distribution, in a previous study, our team incorporated a vertically-aligned one-dimensional array detection system. We measured 2D prompt-gamma distribution moving the developed detection system in the longitudinal direction and verified similarity between 2D prompt-gamma distribution and 2D proton dose distribution. In the present, we have developed two-dimension prompt-gamma measurement system consisted of a 2D parallel-hole collimator, 2D array-type NaI(Tl) scintillators, and multi-anode PMT (MA-PMT) to measure 2D prompt-gamma distribution in real time. The developed measurement system was tested with $^{22}Na$ (0.511 and 1.275 MeV) and $^{137}Cs$ (0.662 MeV) gamma sources, and the energy resolutions of 0.511, 0.662 and 1.275 MeV were $10.9%{\pm}0.23p%$, $9.8%{\pm}0.18p%$ and $6.4%{\pm}0.24p%$, respectively. Further, the energy resolution of the high gamma energy (3.416 MeV) of double escape peak from Am-Be source was $11.4%{\pm}3.6p%$. To estimate the performance of the developed measurement system, we measured 2D prompt-gamma distribution generated by PMMA phantom irradiated with 45 MeV proton beam of 0.5 nA. As a result of comparing a EBT film result, 2D prompt-gamma distribution measured for $9{\times}10^9$ protons is similar to 2D proton dose distribution. In addition, the 45 MeV estimated beam range by profile distribution of 2D prompt gamma distribution was $17.0{\pm}0.4mm$ and was intimately related with the proton beam range of 17.4 mm.

Superior Labral Dimension of the Glenohumeral Joint on Direct MR Arthrography (MRA): Relationship with Presence of SLAP (Superior Labrum Anterior to Posterior) Lesion (직접 자기공명 견관절 조영술 상에서 상부 관절순의 크기: 상부 관절순 전후방 파열과의 관계)

  • Im, Tae Seong;Choi, Jung-Ah;Oh, Joo Han
    • Investigative Magnetic Resonance Imaging
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    • v.18 no.3
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    • pp.193-199
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    • 2014
  • Purpose : To evaluate the relationship between superior labral dimension of the glenohumeral joint on direct MRA and presence of SLAP lesion. Materials and Methods: IRB approval was obtained and informed consent was waived for this retrospective study. Direct MRA studies of the shoulder in 296 patients (300 shoulders) with arthroscopic surgery were analyzed by two radiologists blinded to the arthroscopic results, which were used as gold standard. One of the radiologists reviewed the images twice (session 1 and 2) for the evaluation of intra-observer variability. Transverse and longitudinal dimensions of superior labrum on coronal T1-weighted images were measured as base and height of the inverted triangular-shaped superior labrum and compared between patients with SLAP lesions vs. non-SLAP patients. Presence of meniscoid labrum was noted. Statistical analysis was done using unpaired t-test. Results: Among 279 patients (283 shoulders), 122 patients (43.1%) had SLAP lesions. The mean base/height of superior labrum in SLAP and non-SLAP patients measured on T1-weighted MR image were 8.8 mm / 5.2 mm, 8.5 mm / 4.9 mm for reader 1; 8.2 mm / 4.9 mm, 8.1 mm / 4.5 mm for session 1 of reader 2; 8.0 mm / 4.8 mm, 7.6 mm / 4.3 mm for session 2 of reader 2. In SLAP group, the mean labral height was larger than non-SLAP group with statistically significant difference (p<0.05). Fifteen patients (5.3%) had meniscoid labrum according to operation records. Conclusion: In patients with SLAP lesion, the height of the superior glenoid labrum on oblique coronal image of MRA was slightly larger than non-SLAP patients. A larger height of superior glenoid labrum may be associated with SLAP lesions.

Investigation of the Correlation between Seoul Neuropsychological Screening Battery Scores and the Gray Matter Volume after Correction of Covariates of the Age, Gender, and Genotypes in Patients with AD and MCI (알츠하이머 치매 및 경도인지기능장애 환자에서 나이, 성별, 유전자형을 고려한 뇌 회백질 부피와 표준신경심리검사와의 상관관계 연구)

  • Lee, Seung-Yeon;Yoon, Soo-Young;Kim, Min-Ji;Rhee, Hak Young;Ryu, Chang-Woo;Jahng, Geon-Ho
    • Investigative Magnetic Resonance Imaging
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    • v.17 no.4
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    • pp.294-307
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    • 2013
  • Purpose : To investigate the correlations between Seoul Neuropsychological Screening Battery (SNSB) scores and the gray matter volumes (GMV) in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI) and cognitively normal (CN) elderly subjects with correcting the genotypes. Materials and Methods: Total 75 subjects were enrolled with 25 subjects for each group. The apolipoprotein E (APOE) epsilon genotypes, SNSB scores, and the 3D T1-weighted images were obtained from all subjects. Correlations between SNSB scores and GMV were investigated with the multiple regression method for each subject group using both voxel-based and region-of-interest-based analyses with covariates of age, gender, and the genotype. Results: In the AD group, Rey Complex Figure Test (RCFT) delayed recall scores were positively correlated with GMV. In the MCI group, Seoul Verbal Learning Test (SVLT) scores were positively correlated with GMV. In the CN group, GMV negatively correlated with Boston Naming Test (K-BNT) scores and Mini-Mental State Examimation (K-MMSE) scores, but positively correlated with RCFT scores. Conclusion: When we used covariates of age, gender, and the genotype, we found statistically significant correlations between some SNSB scores and GMV at some brain regions. It may be necessary to further investigate a longitudinal study to understand the correlation.

A study and the growth and the development of microvascular complications in patients with type 1 diabetes mellitus (1형 당뇨병 환자의 성장과 미세혈관 합병증 발생에 대한 연구)

  • Lee, Young Ah;Yun, Kyong-Ah;Shin, Choong Ho;Yang, Sei Won
    • Clinical and Experimental Pediatrics
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    • v.50 no.2
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    • pp.190-197
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    • 2007
  • Purpose : Reduced growth and microvascular complications have been recognized as consequences of type 1 diabetes mellitus (T1DM). We assessed the effect of T1DM on growth and factors associated with the development of microvascular complications. Methods : We conducted a retrospective longitudinal evaluation of 154 patients above 16 years of age. We analyzed factors which affect final height standard deviation scores (SDS) and development of microvascular complications. Results : Final height SDS was $-0.11{\pm}1.15$ ($-0.26{\pm}1.33$ in females, $0.04{\pm}0.91$ in males). Final height SDS was significantly lower than midparental height SDS and height SDS at diagnosis. There was no difference in final height SDS according to age at onset, existence or nonexistence of complications, or average $HbA_{1C}$. Height SDS at onset of puberty, midparental height SDS and pubertal growth gain affected final height SDS. The number of patients with complications was 37 (24 percent). Microvascular complications developed at a younger age and after longer duration of diabetes in patients with a prepubertal onset of T1DM compared to patients with pubertal onset. Patients with complications had a higher level of average $HbA_{1C}$ than patients without complications. Patients whose microalbuminuria regressed had lower levels of average $HbA_{1C}$, systolic BP, second 24h urine microalbumin than patients with persistant or progressed microalbuminuria. Conclusion : The results suggest that degrees of glycemic control don't affect final height, but various factors associated with T1DM can impair growth potential. Additionally, the degrees of glycemic control and puberty affect the development of microvascular complications.