• Animal Bioscience
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• 제35권5호
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• pp.648-658
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• 2022

Objective: The identification of nonlinear mixed models that describe the growth trajectory of New Zealand rabbits was performed based on weight records and carcass measures obtained using ultrasonography. Methods: Phenotypic records of body weight (BW) and loin eye area (LEA) were collected from 66 animals raised in a didactic-productive module of cuniculture located in the southern Piaui state, Brazil. The following nonlinear models were tested considering fixed parameters: Brody, Gompertz, Logistic, Richards, Meloun 1, modified Michaelis-Menten, Santana, and von Bertalanffy. The coefficient of determination (R²), mean squared error, percentage of convergence of each model (%C), mean absolute deviation of residuals, Akaike information criterion (AIC), and Bayesian information criterion (BIC) were used to determine the best model. The model that best described the growth trajectory for each trait was also used under the context of mixed models, considering two parameters that admit biological interpretation (A and k) with random effects. Results: The von Bertalanffy model was the best fitting model for BW according to the highest value of R² (0.98) and lowest values of AIC (6,675.30) and BIC (6,691.90). For LEA, the Logistic model was the most appropriate due to the results of R² (0.52), AIC (783.90), and BIC (798.40) obtained using this model. The absolute growth rates estimated using the von Bertalanffy and Logistic models for BW and LEA were 21.51g/d and 3.16 cm², respectively. The relative growth rates at the inflection point were 0.028 for BW (von Bertalanffy) and 0.014 for LEA (Logistic). Conclusion: The von Bertalanffy and Logistic models with random effect at the asymptotic weight are recommended for analysis of ponderal and carcass growth trajectories in New Zealand rabbits. The inclusion of random effects in the asymptotic weight and maturity rate improves the quality of fit in comparison to fixed models.

• 한국식품위생안전성학회지
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• 제38권6호
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• pp.449-456
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• 2023

본 논문은 적은 농도로 존재하는 Vibrio parahaemolyticus를 6시간이내에 10⁶ CFU/mL까지 신속하게 배양가능한 배지인 Rapid Enrichment Broth for V. parahaemolyticus(REB-V)를 개발하여 V. parahaemolyticus를 신속하게 검출할 수 있도록 하였다. Modified Gompertz model과 RSM를 활용하여 V. parahaemolyticus를 신속하게 증균할 수 있도록 첨가 성분을 최적화하였다. 그 결과 2%(w/v) NaCl BPW에 D-(+)-mannose 0.3 g/L, L-valine 0.2 g/L, magnesium sulfate 0.2 g/L를 첨가하였을 때 V. parahaemolyticus의 증균량이 최대였다. REB-V의 배양조건을 pH 7.84와 37℃으로 최적화하였으며, 2%(w/v) NaCl BPW와 비교하여 REB-V의 증균 효율을 확인하기 위해 7시간 증균을 통해 증균량을 평가하였다. 또한 매시간마다 배양액에서 DNA를 추출하였고, 추출한 DNA로 real-time PCR을 수행하여 REB-V의 분자진단법 적용가능성을 확인하였다. 그 결과 7시간 동안 2%(w/v) NaCl BPW에서 V. parahaemolyticus는 5.452±0.151 Log CFU/mL까지 증균되었고, REB-V에서는 7.831±0.323 Log CFU/mL의 V. parahaemolyticus가 증균되었다. 최종적으로 REB-V에서 6시간 이내에 10⁶ CFU/mL 이상으로 증균된 것을 확인하였고, REB-V의 증균속도가 2%(w/v) NaCl BPW보다 빠르고 같은 시간 내의 증균량이 2%(w/v) NaCl BPW보다 많았음을 통해 REB-V의 증균효율이 우수한 것으로 확인되었다.

• 한국축산식품학회지
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• 제34권1호
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• pp.80-87
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• 2014

Ready-to-eat (RTE) Jokbal (Pig's trotter), which consists of pig's feet cooked in soy sauce and various spices, is a very popular and widely sold in Korean retail markets. Commercially, the anaerobically packed Jokbal have also become a popular RTE food in several convenience stores. This study evaluates the effects of storage temperature and packaging methods for the growth of C. perfringens in Jokbal. Growth kinetic parameters of C. perfringens in aerobically and anaerobically packed Jokbals are determined at each temperature by the modified Gompertz equation. The lag time, specific growth rate, and maximum population density of C. perfringens are being analyzed as a function of temperature and packaging method. The minimum growth temperature of C. perfringens in aerobically and anaerobically packed Jokbal is $24^{\circ}C$ and $18^{\circ}C$, respectively. The C. perfringens in Jokbal did not grow under conditions of over $50^{\circ}C$ regardless of the packaging methods, indicating that the holding temperature of Jokbal in markets must be maintained at above $50^{\circ}C$ or below $18^{\circ}C$. Growth of C. perfringens in anaerobically packed Jokbal is faster than in aerobically packed Jokbal when stored under the same conditions. This indicates that there are a higher risks associated with C. perfringens for anaerobically packed meat products.

• Journal of Microbiology and Biotechnology
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• 제26권4호
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• pp.739-747
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• 2016

The rational utilization of crop straw as a raw material for natural gas production is of economic significance. In order to increase the efficiency of biogas production from agricultural straw, seasonal restrictions must be overcome. Therefore, the potential for biogas production via anaerobic straw digestion was assessed by exposing fresh, silage, and dry yellow corn straw to cow dung liquid extract as a nitrogen source. The characteristics of anaerobic corn straw digestion were comprehensively evaluated by measuring the pH, gas production, chemical oxygen demand, methane production, and volatile fatty acid content, as well as applying a modified Gompertz model and high-throughput sequencing technology to the resident microbial community. The efficiency of biogas production from fresh straw (433.8 ml/g) was higher than that of production from straw silage and dry yellow straw (46.55 ml/g and 68.75 ml/g, respectively). The cumulative biogas production from fresh straw, silage straw, and dry yellow straw was 365 l^-1 g^-1 VS, 322 l^-1 g^-1 VS, and 304 l^-1 g^-1 VS, respectively, whereas cumulative methane production was 1,426.33%, 1,351.35%, and 1,286.14%, respectively, and potential biogas production was 470.06 ml^-1 g^-1 VS, 461.73 ml^-1 g^-1 VS, and 451.76 ml^-1 g^-1 VS, respectively. Microbial community analysis showed that the corn straw was mainly metabolized by acetate-utilizing methanogens, with Methanosaeta as the dominant archaeal community. These findings provide important guidance to the biogas industry and farmers with respect to rational and efficient utilization of crop straw resources as material for biogas production.

• 한국어류학회지
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• 제8권1호
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• pp.49-55
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• 1996

무지개송어, Oncorhynchus mykiss 난황자어의 부상기 이전까지의 부화일수에 따른 전장(TL)성장식은 $TLt=2.7e^{-1.24{\cdot}e^{-0.11t}}(r^{2}=0.66)$, 전중(TW)성장식은 $TWt=1.8e^{-2.03{\cdot}e^{-0.11t}}(r^{2}=0.66)$, 체세포중량(SW)성장식은 $SWt=1.8e^{-5.41{\cdot}e^{-0.13t}}(r^{2}=0.83)$로 나타났다. 부화일수 경과에 따른 난황장, 난황고, 난황부피는 감소를 나타내는 직선식이였다. 전중-전장, 체세포중량-전장, 난황장-전장, 난황고-전장, 난황부피-전장, 난황중-전장, 난황중-전중, 난황중-난황고 및 난황중-난황장의 성장형질간의 상대성장식은 부화일 경과에 따라 난황홉수 경향을 반영하였다.

• 한국축산식품학회지
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• 제30권5호
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• pp.730-738
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• 2010

We developed predictive growth models for Staphylococcus aureus and Bacillus cereus on various food matrices consisting primarily of ready-to-eat (RTE) foods. A cocktail of three S. aureus strains, producing enterotoxins A, C, and D, or a B. cereus strain, were inoculated on sliced bread, cooked rice, boiled Chinese noodles, boiled bean sprouts, tofu, baked fish, smoked chicken, and baked hamburger patties at an initial concentration of 3 log CFU/g and stored at 8, 10, 13, 17, 24, and $30^{\circ}C$. Growth kinetic parameters were determined by the Gompertz equation. The square-root and Davey models were used to determine specific growth rate and lag time values, respectively, as a function of temperature. Model performance was evaluated based on bias and accuracy factors. S. aureus and B. cereus growth were most delayed on sliced bread. Overall, S. aureus growth was significantly (p<0.05) more rapid on animal protein foods than carbohydrate-based foods and vegetable protein foods. The fastest growth of S. aureus was observed on smoked chicken. B. cereus growth was not observed at 8 and $10^{\circ}C$. B. cereus growth was significantly (p<0.05) more rapid on vegetable protein foods than on carbohydrate-based foods. The secondary models developed in this study showed suitable performance for predicting the growth of S. aureus and B. cereus on various food matrices consisting of RTE foods.

• Journal of Preventive Medicine and Public Health
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• 제53권2호
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• pp.117-125
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• 2020

Objectives: This study investigated the role of information and communication technology and women's empowerment in contraceptive discontinuation in Indonesia. Methods: The study used data from the 2017 Indonesia Demographic and Health Survey and monthly contraceptive calendar data. A Gompertz proportional hazards model was used for analysis. Results: The 12-month contraceptive discontinuation rate was higher among women who had used the Internet in the past year, women who were mobile phone owners, and women who reported having fully participated in household decision-making than among their counterparts. These factors significantly impacted the risk of contraceptive discontinuation in Indonesia, even after controlling for contraceptive method, age, parity, contraceptive intent, education, work status, place of residence, and wealth status. Conclusions: After adjustment for the control variables, a higher risk of contraceptive discontinuation was associated with having used the Internet in the past year, owning a mobile phone, and not participating in household decision-making. Higher contraceptive discontinuation risk was also associated with using contraceptive pills, older age, lower parity, intent of spacing births, more education, current unemployment, and rural residence, and the risk was also significantly higher for those in the lowest household wealth quintile than for those in the fourth household wealth quintile. The association of contraceptive discontinuation with the use of modern information and communication technology and relatively disempowerment in household decision-making may imply that information regarding family planning and contraception should be conveyed via social media as part of setting up an eHealth system. This must include a strong communication strategy to empower and educate women in contraceptive decision-making.

• 한국인구학
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• 제20권2호
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• pp.5-42
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• 1997

이 논문은 출산을 전후한 시기에 있는 여성의 노동시장 전출입(labor market transitions)에 관한 필자의 일련의 연구들 중 일부이다. 여성 노동시장에 관한 기존의 이론들을 통합하여 하나의 모델을 제시하고, 노동시장 이탈과 진입의 문제를 다루는 데 적합한 통계적 기법을 소개하였다. 상당수의 여성이 일생을 통하여 적어도 한번씩은 생산노동에 참여하는 현실 속에서 이제 중요한 문제는 노동의 지속과 단절의 문제이다. 이 문제는 여성의 노동시장행위에 대한 동태적인 분석을 요구한다. 본 연구는 응답자의 취업사(work history)와 가족형성사를 장기적으로 관찰한 자료를 이용하고 시간 또는 기간이라는 측면을 분석의 틀에 포함시킨 연구방법을 사용하여 노동의 지속과 단절을 좀더 원래의 개념에 충실하게 포착하였다. 탐색적 분석방법으로 출산을 전후한 시기 여성의 고용단절과 재취업의 행위가 각각 임신, 출산으로부터의 기간에 따라 어떤 패턴으로 나타나는지 살펴보았다. 이 시기 여성의 노동시장 이탈과 진입의 행위는 시간에 따라 일정하게 증가하거나 감소하는 추세를 띠고 있지 않으므로 '사건사분석'(event history analysis)에서 '기간의존성'(duration dependence)을 가정할 때 특별한 주의가 필요하기 때문이다. 탐색적 분석에서 드러난 노동시장행위의 패턴이 어떤 요인에 의해 영향을 받는지를 알아보기 위하여 가설을 세우고 이를 검증하였다. 가족의 수입과 자신의 임금에 대한 경제적 고려 외에 교육을 통해 얻게 되는 경제적 독립과 평등한 성역할에 대한 의지, 그리고 거시적인 경제 여건과 직업의 특성에 의해 조건지워지는 구조적 요인 등을 살펴봄으로써 '인적자본론'의 한계를 짚어 보았다.

• 한국축산식품학회지
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• 제28권2호
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• pp.187-195
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• 2008

The purpose of this study was to establish proper shipping weight and backfat thickness by applying the growth model to backfat thickness, measured by means of not only body weight, but also ultrasonography, and predicting the changes by age. Three breeds, i.e. Duroc, Landrace, and Yorkshie, were analyzed, and the Gompertz, logistic, and Von Bertalanffy model were used for inference with the parameter of the growth model being sex. As a result, both body weight and backfat thickness showed different growth curve parameters and characteristics at inflection points depending on model selection and sex. As for backfat thickness, in estimating the inflection point, unlike the case of body weight, the inflection ages of the boars of the Duroc breed was earlier than that of sows, whereas the inflection ages of the sows of the Landrace and Yorkshire breeds was earlier than that of boars. More than anything else, in the analysis of the changes in backfat thickness according to body weight, as the body weight reached 145kg, the backfat thickness showed much variation as great as 1.7-3.2 cm in each breed and sex. In addition, unlike the other breeds, the boars of the Landrace breed showed an exponential type of relationship between body weight and backfat thickness. As they grow to become 100 kg or heavier, abrupt change in back fat thickness was confirmed. If the growth of body weight and backfat thickness is understood and the genetic relationship is taken advantage of like this, it would be possible to set desired body weight and backfat thickness, and thus help effectively set the shipping time. If not only the phenotype, but also genetic parameters about growth characteristics are estimated and analyzed additionally, more effective data can be generated.

• 한국식품위생안전성학회지
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• 제24권3호
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• pp.232-237
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• 2009

본 연구는 오염된 양상치를 알카리전해수로 세척한 처리구와 비처리구에 오염된 E. coli O157 : H7균이 다양한 온도 (4, 10, 15, 20, 25, 30, $35^{\circ}C$)에 저장할 경우 이균의 specific growth rate (SCR) 과 lag time (LT) 생육변수에 미치는 영향을 조사하기 위한 모델을 개발하기 위하여 수행되었다. E. coli O157 : H7의 specific growth rate (SGR) 과 lag time (LT)를 결정하기 위해 생육도를 Gompertz 식을 사용하여 fitting한 결과, $R^2$값이 0.994로 나타났다. 실험값으로부터 얻은 SGR과 LT는 저장온도에 의존하는 것으로 나타났으며 $4^{\circ}C$에서 $35^{\circ}C$까지 온도가 증가할수록 성장 속도가 증가하는 것으로 나타났다. AIEW 처리구 또는 비처리구의 양상치 에서 E. coli O157 : H7의 성장 kinetics에 대한 저장 온도의 효과를 평가하기 위해 SRG에 대한 두개의 모델을 개발하였다. 유도된 2개의 모델 검증은 $R^2$, $R^2_{Adj}$ (adjusted determination coefficient) 및 MSE (mean square error)를 적용하였으며, 그 결과 $R^2$, $R^2_{Adj}$가 1 (>0.93)에 근접하였으며, 알카리 전해수 처리구 및 비처리구 양상치 모델의 MSE는 각각 0.031, 0.025로 나타났다. 따라서, 본연구에서 개발된 모델의 생육변수는 실험 치에서 얻은 E. coli O157 : H7의 생육변수 결과와 매우 유사한 것으로 나타났다.