• 한국습지학회지
• /
• 제18권4호
• /
• pp.350-356
• /
• 2016

동물의 번식 성공에 가장 큰 요인은 먹이의 선택이고 먹이의 선택은 서식지의 질과 양에 의해 결정되어 지며, 생물량이 높은 습지의 경우 생태계 기능의 지표로서 황조롱이의 사냥 장소의 선택은 서식 장소의 질과 양을 알아보는 중요한 단서가 될 것으로 예상된다. 본 연구는 충남 공주시 유구읍의 황조롱이 사냥장소에 대해 4가지 유형(초지, 논, 밭, 하천변)으로 구분하여, 번식시기인 3월에서 6월까지 3년간 (2014년~2016년) 황조롱이의 행동을 기록하였다. 조사결과, 사냥의 장소는 하천변에서 높은 사냥행동을 보였고, 비행사냥은 5월과 6월에 많이 하는 것으로 조사되었다. 또한 비행사냥의 주요 획득 먹이는 포유류(쥐), 착지행동의 주요 획득 먹이는 곤충류로 조사되었다. 이에 따라, 하천변에서는 주로 비행사냥이 이루어졌으며, 초지나 논과 밭에서는 착지 행동이 비행행동에 비해 높게 조사되었다. 사냥이 이루어지는 지점의 식물이 땅을 덮는 피도는 사냥지역별 차이를 보였으나 식물의 높이는 차이를 보이지 않는 것으로 확인되었고, 사냥 방법에 따른 식물의 높이는 포유류(쥐)를 잡기 위한 비행사냥이 착지사냥보다 낮은 높이를 선호하는 것으로 분석되었다. 이러한 결과들을 바탕으로 황조롱이의 번식기 먹이 선택에서 하천변은 매우 중요한 환경 요소로 판단된다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제28권3호
• /
• pp.303-310
• /
• 2015

The study was conducted to analyze the genetic parameters of somatic cell score (SCS) of Holstein cows, which is an important indicator to udder health. Test-day records of somatic cell counts (SCC) of 305-day lactation design from first to fifth lactations were collected on Holsteins in Korea during 2000 to 2012. Records of animals within 18 to 42 months, 30 to 54 months, 42 to 66 months, 54 to 78 months, and 66 to 90 months of age at the first, second, third, fourth and fifth parities were analyzed, respectively. Somatic cell scores were calculated, and adjusted for lactation production stages by Wilmink's function. Lactation averages of SCS ($LSCS_1$ through $LSCS_5$) were derived by further adjustments of each test-day SCS for five age groups in particular lactations. Two datasets were prepared through restrictions on number of sires/herd and dams/herd, progenies/sire, and number of parities/cow to reduce data size and attain better relationships among animals. All LSCS traits were treated as individual trait and, analyzed through multiple-trait sire models and single trait animal models via VCE 6.0 software package. Herd-year was fitted as a random effect. Age at calving was regressed as a fixed covariate. The mean LSCS of five lactations were between 3.507 and 4.322 that corresponded to a SCC range between 71,000 and 125,000 cells/mL; with coefficient of variation from 28.2% to 29.9%. Heritability estimates from sire models were within the range of 0.10 to 0.16 for all LSCS. Heritability was the highest at lactation 2 from both datasets (0.14/0.16) and lowest at lactation 5 (0.11/0.10) using sire model. Heritabilities from single trait animal model analyses were slightly higher than sire models. Genetic correlations between LSCS traits were strong (0.62 to 0.99). Very strong associations (0.96 to 0.99) were present between successive records of later lactations. Phenotypic correlations were relatively weaker (<0.55). All correlations became weaker at distant lactations. The estimated breeding values (EBVs) of LSCS traits were somewhat similar over the years for a particular lactation, but increased with lactation number increment. The lowest EBV in first lactation indicated that selection for SCS (mastitis resistance) might be better with later lactation records. It is expected that results obtained from these multi-trait lactation model analyses, being the first large scale SCS data analysis in Korea, would create a good starting step for application of advanced statistical tools for future genomic studies focusing on selection for mastitis resistance in Holsteins of Korea.

• Journal of Microbiology and Biotechnology
• /
• 제20권8호
• /
• pp.1219-1225
• /
• 2010

Actinobacillus succinogenes, a representative succinicacid-producing microorganism, is seriously inhibited by ammonium ions, thereby hampering the industrial use of A. succinogenes with ammonium-ion-based materials as the pH controller. Therefore, this study isolated an ammonium-ion-tolerant mutant of A. succinogenes using a continuous-culture technique in which all the environmental factors, besides the stress (ammonium ions), were kept constant. Instead of operating the mutant-generating system as a nutrient-limited chemostat, it was used as a nutrient-unlimited system, allowing the cells to be continuously cultured at the maximum specific growth rate. The mutants were isolated on agar plates containing the acid-base indicator bromothymol blue and a high level of ammonium ions that would normally kill the parent strain by 100%. When cultured in anaerobic bottles with an ammonium ion concentration of 354 mmol/l, the mutant YZ0819 produced 40.21 g/l of succinic acid with a yield of 80.4%, whereas the parent strain NJ113 was unable to grow. When using $NH_4OH$ to buffer the culture pH in a 3.0 l stirredbioreactor, YZ0819 produced 35.15 g/l of succinic acid with a yield of 70.3%, which was 155% higher than that produced by NJ113. In addition, the morphology of YZ0819 changed in the fermentation broth, as the cells were aggregated from the beginning to the end of the fermentation. Therefore, these results indicate that YZ0819 can efficiently produce succinic acid when using $NH_4OH$ as the pH controller, and the formation of aggregates can be useful for transferring the cells from a cultivation medium for various industrial applications.

• 한국환경농학회지
• /
• 제29권3호
• /
• pp.287-292
• /
• 2010

사과원 토양의 지속적인 생산성을 위해 토양생물의 변화를 파악하는 것이 중요하므로, 피복식물 재배에 따른 미생물 PLFA 및 미소동물의 개체밀도 변화를 조사하였다. 피복식물은 두과식물인 호밀, 귀리, 들묵새와 두과식물인 자운영, 레드클로버, 크림슨클로버, 헤어리배치를 대상으로 하였다. 청경구에 비하여 피복식물을 재배하였을 때 미생물 PLFA 수치 및 미소동물이 증가하였기 때문에 청경구보다는 피복식물로 토양을 관리하는 것이 토양생물을 증가시키는데 유리할 것으로 사료된다. 미생물 PLFA 수치에서는 피복식물간 차이가 적었지만, 화본과식물 중에서는 들묵새와 두과식물 중에서는 자운영이 토양의 미소절족동물의 개체밀도를 증가시키는 효과가 비교적 큰 것으로 나타났다. 본 결과는 적절한 피복식물 선정을 통한 효과적인 유기물분해와 안정적인 양분공급을 위한 기초자료로 활용될 수 있을 것이다.

• 보건행정학회지
• /
• 제17권3호
• /
• pp.87-105
• /
• 2007

The purpose of this study was to analyze whether nonemergency, isolated coronary artery bypass graft (CABG) surgery for high- or low-risk patients biases the assessment of the risk-adjusted mortality rates of hospitals. This study used 2002 National Health Insurance claims data for tertiary hospitals in Korea. The study sample consisted of 1,959 patients from 23 tertiary hospitals. The risk-adjustment model used the patients' biological, admission, and comorbidity data identified in the claims. The subjects were classified into high- and low-risk groups based on predicted surgical risk. The crude mortality rates and risk-adjusted mortality rates for low-risk, high-risk, and all patients in a hospital were compared based on the rank and the four intervals defined by quartile. Also, the crude mortality rates of the three groups were compared with their 95% confidence intervals of predicted mortality rates. The C-statistic (0.83) and Hosmer-Lemeshow test ($X^2$=11.47, p=0.18) indicated that the risk-adjustment model performed well. Presenting crude mortality rates with their 95% confidence intervals of predicted rates showed higher agreements among the three groups than using the rank or intervals of mortality rates defined by quartile in the hospital performance assessment. The crude mortality rates for the low-risk patients in 21 of the 23 hospitals were located on the same side of their 95% confidence intervals compared to that for all patients. High-risk patients and all patients differed at only one hospital. In conclusion, the impact of risk selection by hospital on the assessment results was the smallest when comparing the crude inpatient mortality rates of CABG patients with the 95% confidence intervals of predicted mortality rates. Given the increasing importance of quality improvements in Korean health policy, it will be necessary to use the appropriate method of releasing the hospital performance data to the public to minimize any unwanted impact such as risk-based hospital selection.

• 한국축산식품학회지
• /
• 제34권5호
• /
• pp.614-621
• /
• 2014

This study was conducted to isolate and characterize bacteriocin-producing bacteria against Clostridium perfringens (C. perfringens) from domestic animals to determine their usefulness as probiotics. Bacteriocin-producing bacteria were isolated from pig feces by the spot-on-lawn method. A total of 1,370 bacterial stains were isolated, and six were tentatively selected after identifying the inhibitory activity against the pathogenic indicator C. perfringens KCTC 3269 and KCTC 5100. The selected strains were identified as Enterococcus faecalis (E. faecalis) by 16s rRNA sequencing. Most of the isolated bacterial strains were resistant to 0.5% bile salts for 48 h and remained viable after 2 h at pH 3.0. Some E. faecalis also showed strong inhibitory activity against Listeria monocytogenes KCTC 3569, KCTC 3586 and KCTC 3710. In the present study, we finally selected E. faecalis AP 216 and AP 45 strain based on probiotic selection criteria such as antimicrobial activity against C. perfringens and tolerance to acid and bile salts. The bacteriocins of E. faecalis AP 216 and AP 45 strains were highly thermostable, showing anticlostridial activities even after incubation at $121^{\circ}C$ for 15 min. These bacteriocin-producing bacteria and/or bacteriocins could be used in feed manufacturing as probiotics as an alternative to antibiotics in the livestock industry.

• 한국도로학회논문집
• /
• 제17권4호
• /
• pp.127-133
• /
• 2015

PURPOSES: The purpose of this study is to develop a methodology to prioritize sidewalk construction on rural national highways. METHODS : In order to determine an appropriate prioritization for sidewalk construction, we developed a specific methodology. The proposed methodology includes three main steps: 1) Analytic Hierarchy Process (AHP) methods, 2) Subjective evaluation of relevant road agencies for the candidate sidewalks along rural national highways, and 3) Field study conduction. Each step has four phases. The primary feature of this methodology is the addition of expert consultation and survey data, as well as a field study. In addition, the method could guarantee flexibility in selection for evaluation criteria. As a result, the proposed methodology could be used as a general procedure for application to other roadway classifications when considering sidewalk construction. RESULTS: In order to demonstrate the reasonableness of the proposed methodology, a case study was performed for exactly 100 candidate sites for sidewalk construction on rural national highways. All required evaluation scores were properly produced for each candidate site. By doing so, decision-makers can determine the priority for sidewalk construction at these sites by reviewing quantitatively and qualitatively considered data. CONCLUSIONS: The results of the case study can be applied to a long-term fundamental plan for sidewalk construction on rural national highways. Furthermore, this methodology could be employed to prioritize a small-scale SOC project(e. g. bicycle or pedestrian roads).

• Journal of the Korean Statistical Society
• /
• 제32권2호
• /
• pp.121-150
• /
• 2003

The National Health Interview Survey (NHIS) is one of the surveys used to assess the health status of the US population. One indicator of the nation's health is the total number of doctor visits made by the household members in the past year, There is a substantial nonresponse among the sampled households, and the main issue we address here is that the nonrespones mechanism should not be ignored because respondents and nonrespondents differ. It is standard practice to summarize the number of doctor visits by the binary variable of no doctor visit versus at least one doctor visit by a household for each of the fifty states and the District of Columbia. We consider a nonignorable nonresponse model that expresses uncertainty about ignorability through the ratio of odds of a household doctor visit among respondents to the odds of doctor visit among all households. This is a hierarchical model in which a nonignorable nonresponse model is centered on an ignorable nonresponse model. Another feature of this model is that it permits us to "borrow strength" across states as in small area estimation; this helps because some of the parameters are weakly identified. However, for simplicity we assume that the hyperparameters are fixed but unknown, and these hyperparameters are estimated by the EM algorithm; thereby making our method Bayes empirical Bayes. Our main result is that for some of the states the nonresponse mechanism can be considered non-ignorable, and that 95% credible intervals of the probability of a household doctor visit and the probability that a household responds shed important light on the NHIS.

• Journal of the Korean Wood Science and Technology
• /
• 제48권6호
• /
• pp.869-877
• /
• 2020

The power consumption in the low consistency (LC) refining is an important indicator for the optimal control of the process and it is composed of the net power and the no-load power. The refining efficiency and process characterization of LC refining are directly affected by power consumption. In this paper, the effect of pulp consistency and average fiber length on the power consumption and refining efficiency were studied through the LC refining trials conducted by an experimental disc refiner. It is found that the curve of power-gap clearance can be divided into constant power section, power reduction section, and power increase section. And the no-load power and the adjustable domain of loading applied by the refining plates will increase as the increase of pulp consistency, while the increase of net power is larger than that of no-load power which makes the increasing of refining efficiency. Meanwhile, the adjustable domain of loading applied by the refining plates can be slightly improved by increasing the average fiber length, but its effect on the no-load power in the LC refining process can be neglected. The study of power consumption in LC refining is of positive significance for the proper selection of pulp properties in LC refining, in-depth exploration of refining mechanism, and energy consumption reduction in refining.

• 에너지공학
• /
• 제22권2호
• /
• pp.156-168
• /
• 2013

이 연구에서는 2007년, 2010년에 수행한 울릉분지 1, 2차 시추 지역의 시추공(UBGH1-1, UBGH1-4, UBGH1-9, UBGH1-10, UBGH1-14, UBGH2-2-1, UBGH2-2-2, UBGH2-6, UBGH2-9, UBGH2-10, UBGH2-11)에서 취득한 물리검층 및 코어분석 자료로 추정한 가스하이드레이트 함유층 주요 물성 자료를 활용하여 불균질성을 반영할 격자 수준의 3차원 공간 분포 모델링을 수행하였다. 가스하이드레이트 함유층 내 퇴적상의 공간 분포 추정을 위하여 퇴적상 추정 자료를 각 시추공별로 3차원 격자셀에 입력하고 순차지표시뮬레이션으로 3차원 분포를 모델링하였다. 가스하이드레이트 함유층의 공극률과 가스하이드레이트포화율은 퇴적상 분포 모델을 기반으로 순차가우스시뮬레이션을 통해 3차원 공간 물성 분포를 추정하였다.