• 제목/요약/키워드: Fixed-Effects Model

검색결과 630건 처리시간 0.043초

Estimation of the genetic milk yield parameters of Holstein cattle under heat stress in South Korea

  • Lee, SeokHyun;Do, ChangHee;Choy, YunHo;Dang, ChangGwon;Mahboob, Alam;Cho, Kwanghyun
    • Asian-Australasian Journal of Animal Sciences
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    • 제32권3호
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    • pp.334-340
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    • 2019
  • Objective: The objective of this study was to investigate the genetic components of daily milk yield and to re-rank bulls in South Korea by estimated breeding value (EBV) under heat stress using the temperature-humidity index (THI). Methods: This study was conducted using 125,312 monthly test-day records, collected from January 2000 to February 2017 for 19,889 Holstein cows from 647 farms in South Korea. Milk production data were collected from two agencies, the Dairy Cattle Genetic Improvement Center and the Korea Animal Improvement Association, and meteorological data were obtained from 41 regional weather stations using the Automated Surface Observing System (ASOS) installed throughout South Korea. A random regression model using the THI was applied to estimate genetic parameters of heat tolerance based on the test-day records. The model included herd-year-season, calving age, and days-in-milk as fixed effects, as well as heat tolerance as an additive genetic effect, permanent environmental effect, and direct additive and permanent environmental effect. Results: Below the THI threshold (${\leq}72$; no heat stress), the variance in heat tolerance was zero. However, the heat tolerance variance began to increase as THI exceeded the threshold. The covariance between the genetic additive effect and the heat tolerance effect was -0.33. Heritability estimates of milk yield ranged from 0.111 to 0.176 (average: 0.128). Heritability decreased slightly as THI increased, and began to increase at a THI of 79. The predicted bull EBV ranking varied with THI. Conclusion: We conclude that genetic evaluation using the THI function could be useful for selecting bulls for heat tolerance in South Korea.

재임기간에 따른 사외이사 비율과 기업가치 (The Ratio of Outside Directors according to their Tenure and Firm Value)

  • 임새훈;박영석
    • 아태비즈니스연구
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    • 제11권4호
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    • pp.225-241
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    • 2020
  • Purpose - The purpose of this study was to examine the effect of the ratio of outside directors, especially the ratio of outside directors according to their tenure, on firm value. Design/methodology/approach - This study collected total 3,861 firm-year data about companies listed KRX KOSPI market in Korea. The Pooled Ordinary Least Square Model and Panel Fixed Effects Model were hired in order to analyze the data. Findings - First, it was found that the ratio of outside directors for total sample had no significant effect on firm value, and the estimation coefficient of dummy variable for the average tenure less than 3 years had a significant positive(+) effect on firm value. Second, the ratio of outside directors corresponding to the tenure of less than 3 years had a significant positive(+) effect on the firm value. On the contrary, the ratio of outside directors corresponding to the tenure of 3 years or more had a significant negative(-) effect on firm value. Third, the ratio of outside directors corresponding to the tenure for more than 6 years did not show any significant influence on firm value. Research implications or Originality - First, if other matters are not additionally considered, keeping the tenure of outside directors shortly on average could help to increase firm value. Second, in the case of firms facing the decision to reappoint outside directors for the first time, it is highly likely that the firm value would decrease on average, so careful decisionmaking considering various aspects is required. However, this study does not take into account the legal standards for the appointment of outside directors, diversity of outside directors, and the actual independence of outside directors according to other criteria in the analysis. Therefore, if these factors are considered, there is a possibility that the empirical analysis results of this study may show different patterns.

Estimation of genetic parameters for pork belly traits

  • Seung-Hoon Lee;Sang-Hoon Lee;Hee-Bok Park;Jun-Mo Kim
    • Animal Bioscience
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    • 제36권8호
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    • pp.1156-1166
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    • 2023
  • Objective: Pork belly is a cut of meat with high worldwide demand. However, although the belly is comprised of multiple muscles and fat, unlike the loin muscle, research on their genetic parameters has yet to focus on a representative cut. To use swine breeding, it is necessary to estimate heritability against pork belly traits. Moreover, estimating genetic correlations is needed to identify genetic relationship among the traditional carcass and meat quality traits. This study sought to estimate the heritability of the carcass, belly, and their component traits, as well as the genetic correlations among them, to confirm whether these traits can be improved. Methods: A total of 543 Yorkshire pigs (406 castrated males and 137 females) from 49 sires and 244 dam were used in this study. To estimate genetic parameters, a total of 12 traits such as lean meat production ability, meat quality and pork belly traits were chosen. The heritabilities were estimated by using genome-wide efficient mixed model association software. The statistical model was selected so that farm, carcass weight, sex, and slaughter season were fixed effects. In addition, its genetic parameters were calculated via MTG2 software. Results: The heritability estimates for the 7th belly slice along the whole plate and its components were low to moderate (0.07±0.07 to 0.33±0.07). Moreover, the genetic correlations among the carcass and belly traits were moderate to high (0.28±0.20 to 0.99±0.31). Particularly, the rectus abdominis muscle exhibited a high absolute genetic correlation with the belly and meat quality (0.73±52 to 0.93±0.43). Conclusion: A moderate to high correlation coefficient was obtained based on the genetic parameters. The belly could be genetically improved to contain a larger proportion of muscle regardless of lean meat production ability.

Effects of dietary flavonoids on performance, blood constituents, carcass composition and small intestinal morphology of broilers: a meta-analysis

  • Prihambodo, Tri Rachmanto;Sholikin, Muhammad Miftakhus;Qomariyah, Novia;Jayanegara, Anuraga;Batubara, Irmanida;Utomo, Desianto Budi;Nahrowi, Nahrowi
    • Animal Bioscience
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    • 제34권3_spc호
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    • pp.434-442
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    • 2021
  • Objective: This study aims to evaluate the influence of dietary flavonoids on the growth performance, blood and intestinal profiles, and carcass characteristics of broilers by employing a meta-analysis method. Methods: A database was built from published studies which have reported on the addition of various levels of flavonoids from herbs into broiler diets and then monitored growth performance, blood constituents, carcass proportion and small intestinal morphology. A total of 42 articles were integrated into the database. Several forms of flavonoids in herbs were applied in the form of unextracted and crude extracts. The database compiled was statistically analyzed using mixed model methodology. Different studies were considered as random effects, and the doses of flavonoids were treated as fixed effects. The model statistics used were the p-values and the Akaike information criterion. The significance of an effect was stated when its p-value was <0.05. Results: Dietary flavonoids increased (quadratic pattern; p<0.05) the average daily gain of broilers in the finisher phase. There was a reduction (p<0.01) in the feed conversion ratio of the broilers both in the starter (linear pattern) and finisher phases (quadratic pattern). The mortality rate tended to decrease linearly (p<0.1) with the addition of flavonoids, while the carcass parameter was generally not influenced. A reduction (p<0.001) in cholesterol and malondialdehyde concentrations (both linearly) was observed, while super oxide dismutase activity increased linearly (p<0.001). Increasing the dose of flavonoids increased (p<0.01) the villus height (VH) and villus height and crypt depth (VH:CD) ratio (p<0.05) in the duodenum. Similarly, the VH:CD ratio was elevated (p<0.001) in the jejunum following flavonoid supplementation. Conclusion: Increasing levels of flavonoids in broilers diet leads to an improvement in growth performance, blood constituents, carcass composition and small intestinal morphology.

특정 종돈집단의 임신기간, 이유후초종부일, 총산자수 및 사산에 대한 유전모수 추정 (Estimation of Genetic Parameters for Gestation Length, Wean to First Service, Litter Size and Stillborn Piglets in a Closed Nucleus Swine Breeding Herd)

  • 이득환;손지현
    • Journal of Animal Science and Technology
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    • 제55권5호
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    • pp.389-398
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    • 2013
  • 본 연구는 폐쇄종돈군을 유지하면서 장기간 선발육종을 실시한 Landrace 및 Yorkshire 모계 종돈집단에서 임신기간, 총산자수, 이유후초종부일 및 사산두수에 대한 유전적 변이성을 제시함으로써 이들 형질들에 대한 선발지표에 참고자료를 제시하고자 실시하였다. 분석에 이용된 자료는 상기의 형질들에 대하여 사전 이상치를 제외한 후, Landrace 품종에서 1,910두의 모돈으로부터 수집된 7,616복의 기록 및 Yorkshire 품종 2283두의 모돈으로부터 수집된 총 10,454복의 기록을 이용하였다. 분석형질들에 대한 유전변이를 추정하기 위하여 상기의 4개 형질을 동시에 고려한 혼합모형을 설정하였으며, 특히 사산두수에 대하여는 정규성에 크게 위배되기 때문에 범주형 자료로 가정하여 다형질 선형-임계형 반복동물개체모형을 설정하여 분석하였다. 분석방법으로서는 Bayesian 추론의 일종인 Gibbs Sampling (GS) 방법에 의하여 모수의 사후분포 함수로부터 모수에 대한 GS을 50,000회 실시하고 burn-in을 제외한 후 모수의 사후분포에 대한 통계량을 제시하였다. 유전변이를 추정한 결과, 임신기간에 대한 유전력은 0.21~0.35로 추정되었고, 이유후초종부일에서는 0.16~0.23, 총산자수는 0.14~0.16 및 사산두수에 있어서는 0.09~0.10으로 추정되었다. 임신기간에 대한 유전상관 추정치는 총산자수 및 사산두수에서 부의 상관을 갖는 것으로 추정되었고 총산자수와 사산두수와는 정의 상관을 갖는 것으로 추정되었다. 총산자수와 이유후초발정일 간의 유전상관은 낮은 부의 상관을 갖는 것으로 추정되었으며 임신기간과 이유후 초종부일 간에는 유전적 상관관계가 매우 미약한 것으로 분석되었다. 따라서 총산자수를 개량하고자 할 때, 사산두수를 고려하여 선발지표를 설정함이 타당할 것으로 판단되었다.

Estimation of Weaning Age Effects on Growth Performance in Berkshire Pigs

  • Do, C.H.
    • Asian-Australasian Journal of Animal Sciences
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    • 제25권2호
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    • pp.151-162
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    • 2012
  • Analysis for back fat thickness (BFAT) and daily body weight gains from birth to the end of a performance test were conducted to find an optimal method for estimation of weaning age effects and to ascertain impacts of weaning age on the growth performance of purebred Berkshire pigs from a closed population in Korea. Individual body weights were measured at birth (B), at weaning (W: mean, 22.9 d), at the beginning of the performance test (P: mean, 72.7 d), and at the end of the performance test (T: mean, 152.4 d). Further, the average daily gains in body weight (ADG) of 3,713 pigs were analyzed for the following periods: B to W (DGBW), W to P (DGWP), P to T (DGPT), B to P (DGBP), B to T (DGBT), and W to T (DGWT). Weaning ages ranged from 17 to 34 d, and were treated as fixed (WF), random with (WC) and random without (WU) consideration of an empirical relationship between weaning ages in the models. WF and WC produced the lowest AIC (Akaike Information Criterion) and least fractions of error variance components in multi-traits analysis, respectively. The fractions of variances due to diverse weaning age and the weaning age correlations among ADGs of different stages (when no overlapping allowed) by WC ranged from 0.09 to 0.35 and from -0.03 to 0.44, respectively. The maximum weaning age effects and optimal back fat thicknesses were attained at weaning ages of 27 to 32 d. With the exception of DGBW, the effects of weaning age on the ADGs increased (ranging from 1.50 g/d to 7.14 g/d) with increased weaning age. In addition, BFAT was reduced by 0.106 mm per increased day in weaning age. In conclusion, WC produced reasonable weaning age correlations, and improved the fitness of the model. Weaning age was one of crucial factors (comparable with heritability) influencing growth performance in Berkshire pigs. Further, these studies suggest that increasing weaning age up to 32 d can be an effective management strategy to improve growth performance. However, additional investigations of the costs and losses related to extension of the suckling period and on the extended range of weaning age are necessary to determine the productivity and safety of this practice in a commercial herd and production system.

중국 품목별 수출입이 세계 경제에 미치는 영향 실증분석 (The Impacts of Chinese Seaborne Trade Volume on The World Economy)

  • 안영균;이민규
    • 무역학회지
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    • 제42권6호
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    • pp.111-129
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    • 2017
  • 세계은행 통계에 따르면 2013~2016년 기간 중 세계 경제 성장에 대한 중국의 기여도는 31.6%인 것으로 나타났다. 이는 미국, EU 및 일본의 기여도를 합한 29.0%에 비해 높은 수치로서 중국 경제가 세계 경제에 미치는 영향력이 상당히 크다고 볼 수 있다. 본 연구는 중국의 주요 품목별(화학제품, 곡물, 철재, 원유, 컨테이너) 연도별 수출입 해상물동량이 세계 경제성장에 미치는 영향을 시계열 데이터 분석 모형을 적용하여 분석하였다. 총 분석기간은 1999~2016년이며, 제1기(1999~2007년)와 제2기(2008~2016년)의 시기별 분석을 수행함으로써 중국 무역이 세계 경제에 미치는 영향력 측면에서 시기별로 어떠한 구조적 변화가 발생했는지 조명하였다. 특히 대다수 선행연구들이 세계 무역이 세계 경제에 미치는 영향력을 분석하였다면, 본 연구는 중국 무역의 영향력을 분석하여 세계 무역 대국으로 부상하고 있는 중국을 집중적으로 분석하였다는 데 의의가 있다.

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노인장기요양보험제도가 대상노인 및 부양가족의 삶의 질과 가족관계 만족도에 미치는 영향 - 성향점수매칭(PSM)과 이중차이(DD) 결합모형을 이용한 분석 - (The Effects of Long-term Care Insurance on the Life Satisfaction and Satisfaction in Family Relationships - The DD Method Combined with Propensity Score Matching -)

  • 권현정;조용운;고지영
    • 한국사회복지학
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    • 제63권4호
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    • pp.301-326
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    • 2011
  • 이 연구는 우리나라 노인장기요양보험의 제도성과를 평가하는데 그 목적이 있다. 정확한 제도성과를 추정하기 위하여 준실험적 방법인 성향점수매칭과 이중차이 결합모형을 이용해 타당성을 저해할 수 있는 요인들을 제거하였다. 노인장기요양보험제도가 사회적 성과변수인 대상노인과 부양가족의 삶의 질과 가족관계 만족도에 미치는 영향을 분석하기 위해 한국복지패널 3-4차 조사자료를 이용하여 성향점수추정을 통해 실험집단과 비교집단을 매칭한 후, 정책시행 이전과 이후 실험집단과 비교집단 간의 성과의 차이를 추정하기 위해 패널고정효과모형을 이용한 이중차이분석을 실시하였다. 그 결과, 노인장기요양보험제도의 대상노인과 부양가족의 삶의 질은 통계적으로 유의미하지 않았고, 가족관계 만족도는 제도시행 이전에 비해 제도시행 이후 향상된 것을 확인할 수 있었다. 이러한 결과는 노인장기요양보험이 실시되고 제도가 충분히 성숙된 시점에 이루어진 평가가 아니라는 한계점을 가지지만, 노인장기요양보험제도의 최종 목표인 대상노인과 부양가족의 삶의 질 향상이라는 정책의 목표실현과 향후 제도개선에 있어서 중요한 함의를 가진다.

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Dose-dependent effects of a microbial phytase on phosphorus digestibility of common feedstuffs in pigs

  • Almeida, Ferdinando N.;Vazquez-Anon, Mercedes;Escobar, Jeffery
    • Asian-Australasian Journal of Animal Sciences
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    • 제30권7호
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    • pp.985-993
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    • 2017
  • Objective: The objective of this study was to evaluate increasing doses of a novel microbial phytase (Cibenza Phytaverse, Novus International, St. Charles, MO, USA) on standardized total tract digestibility (STTD) of P in canola meal (CM), corn, corn-derived distiller's dried grains with solubles (DDGS), rice bran (RB), sorghum, soybean meal (SBM), sunflower meal (SFM), and wheat. Methods: Two cohorts of 36 pigs each (initial body weight = $78.5{\pm}3.7kg$) were randomly assigned to 2 rooms, each housing 36 pigs, and then allotted to 6 diets with 6 replicates per diet in a randomized complete block design. Test ingredient was the only dietary source of P and diets contained 6 concentrations of phytase (0, 125, 250, 500, 1,000, or 2,000 phytase units [FTU]/kg) with 0.4% of $TiO_2$ as a digestibility marker. Feeding schedule for each ingredient was 5 d acclimation, 5 d fecal collection, and 4 d washout. The STTD of P increased (linear or exponential $p{\leq}0.001$) with the inclusion of phytase for all ingredients. Results: Basal STTD of P was 37.6% for CM, 37.6% for corn, 68.6% for DDGS, 10.3% for RB, 41.2% for sorghum, 36.7% for SBM, 26.2% for SFM, and 55.1% for wheat. The efficiency of this novel phytase to hydrolyze phytate is best described with a broken-line model for corn, an exponential model for CM, RB, SBM, SFM, and wheat, and a linear model for DDGS and sorghum. Based on best-fit model the phytase dose (FTU/kg) needed for highest STTD of P (%), respectively, was 735 for 64.3% in CM, 550 for 69.4% in corn, 160 for 55.5% in SBM, 1,219 for 57.8% in SFM, and 881 for 64.0% in wheat, whereas a maximum response was not obtained for sorghum, DDGS and RB within the evaluated phytase range of 0 to 2,000 FTU/kg. These differences in the phytase concentration needed to maximize the STTD of P clearly indicate that the enzyme does not have the same hydrolysis efficiency among the evaluated ingredients. Conclusion: Variations in enzyme efficacy to release P from phytate in various feedstuffs need to be taken into consideration when determining the matrix value for phytase in a mixed diet, which likely depends on the type and inclusion concentration of ingredients used in mixed diets for pigs. The use of a fixed P matrix value across different diet types for a given phytase concentration is discouraged as it may result in inaccurate diet formulation.

밀도 변화를 포함하는 3차원 연직함수 전개모형 (A Three-Dimensional Galerkin-FEM Model with Density Variation)

  • 이호진;정경태;소재귀;강관수;정종율
    • 한국해안해양공학회지
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    • 제8권2호
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    • pp.123-136
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    • 1996
  • 본 연구에서는 시 공간적으로 변화하는 밀도구조를 고려한 3차원 연직함수 전개모형을 제안한다. 정수압을 가정하며 열보존식과 상태방정식의 도입으로 밀도변화가 고려된다 수평방향으로의 변화는 유한 차분 격자상에서 계산되며 유속 및 수온의 연직구조는 선형보간함수를 사용하여 계산된다. 구성된 행렬방정식은 유사변환 개념을 도입하여 시간적분된다. 개발된 모델의 테스트를 위해 간단한 이상해역과 황해역에서 대기와 해양간의 열교환에 따른 수온구조 변동을 실험하였다. 이류효과는 열수송방정식에서만 고려하였으며 연직 와동점성계수와 와동확산계수는 시 공간적으로 일정한 값을 사용하였다. 이상해역에서의 수치실험결과 모델영역의 수심의 차이에 따른 열저장의 차이로 인해 수온의 수평적 구배가 발생하였다. 결과적으로 전향력을 고려하지 않을 경우에는 상층에서는 수심이 증가하는 방향으로 흐름이 발생하고 하층에는 반대방향의 흐름이 유도된 반면 전향력을 고려할 경우에는 수온차에 의한 압력구배력과 전향력이 균형을 이루면서 지형류가 뚜렷하게 나타났다. 황해역에서는 복잡한 흐름이 나타났지만 전체적으로는 지형류의 특성이 우세하게 나타났다.

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