• Structural Engineering and Mechanics
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• 제72권6호
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• pp.737-746
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• 2019

Concrete mechanical properties change constantly with age, temperature, humidity and the other environmental factors. This research studies the effects of temperature and age on the development of concrete elastic modulus by a series of prism specimens. Elastic modulus test was conducted at various temperatures and ages in the laboratory to examine the effects of temperature and age on it. The experimental results reveal that the concrete elastic modulus decreases with the rise of temperature but increases with age. Then, a temperature coefficient K is proposed to describe the effects of temperature and validated by existing studies. Finally, on the basis of K, analytical models are proposed to determine the elastic modulus of concrete at a given temperature and age. The proposed models can offer designers an approach to obtain more accurate properties of concrete structures through the elastic modulus modification based on actual age and temperature, rather than using a value merely based on laboratory testing.

• 사회복지연구
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• 제49권2호
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• pp.65-92
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• 2018

노년기 건강과 우울의 긴밀한 관계는 잘 알려져 있다. 본 연구는 열악한 건강상태가 고령층의 우울위험을 높이는 것을 완화하고 예방하기 위한 목적하에, 고령친화적인 공적서비스 자원의 수준과 고령층의 연령에 따라 주관적 건강상태가 우울에 미치는 영향에 어떠한 차이가 나타나는지를 검토하였다. 이를 위해, 전국적으로 조사된 "2017연령통합설문조사"에 참여한 전국 55세 이상 성인 492명의 응답을 활용하여 조절효과분석을 수행하였다. 주요 결과는 다음과 같다. 우선, 주관적 건강상태가 열악할수록 우울이 증가하였는데, 이 같은 경향은 고령친화적인 공적서비스 자원의 수준이 더 양호한 지역에 거주하는 고령층의 경우 완화되었다. 반면, 주관적 건강상태와 우울의 관계에서 연령의 조절효과는 통계적으로 유의미하지 않았다. 구체적으로 어떠한 조건에서 상호작용효과가 나타나는지를 살펴본 결과, 고령친화적인 공적서비스 자원의 수준이 낮을 때 주관적 건강상태가 열악할수록 우울이 증가하는 경향이 고령층의 모든 연령집단에서 공통적으로 드러났다. 또한, 고령층의 연령이 평균(66.6세) 및 그 이상인 경우 고령친화적인 공적서비스 자원 수준이 개선됨에 따라 취약한 주관적 건강상태의 부정적인 영향이 감소하는 완충효과가 확인되었다. 이상의 연구결과를 바탕으로, 본 연구는 지역사회 환경의 개선을 통해 고령층의 건강증진과 우울예방에 기여할 몇 가지 제언을 논의하였다.

• 음성과학
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• 제11권4호
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• pp.163-171
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• 2004

The primary goal of the present study was to explore more detailed evidence for the influence of aging and gender effects on the capability of Korean healthy, ears to generate DPOAEs. DPOAEs were examined in series of human subjects, with clinically nonnal hearing, ranging in age from 10 to 65 years. All 60 Koreans were divided into 6 age groups. Each age group included 10 participants, 5 females and 5 males. The gender effects on the difference between the absolute amplitude and noise floor value in DPOAEs did not exist. The difference increased as the frequency increased. The aging effects on the difference between the absolute amplitude and noise floor value in DPOAEs did exist. The difference increased as the frequency increased but orderly age effects could not be found. The principle finding was that, when compared between emissions in young and old ears, DPOAEs accurately tracked the systematic deterioration of high-frequency hearing in aging individuals. Such results support the need to reestablish the criterion for interpretation of DPOAEs in the elderly.

• Asian-Australasian Journal of Animal Sciences
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• 제22권7호
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• pp.931-936
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• 2009

Body weights of 862 Angora goats between birth and 36 months of age, recorded on a semiyearly basis from 1988 to 2000, were used to estimate genetic, permanent environmental and phenotypic covariance functions. These functions were estimated by fitting a random regression model with 6th order polynomial for direct additive genetic and animal permanent environmental effects and 4th and 5th order polynomial for maternal genetic and permanent environmental effects, respectively. A phenotypic covariance function was estimated by modelling overall animal and maternal effects. The results showed that the most variable coefficient was the intercept for both direct and maternal additive genetic effects. The direct additive genetic (co)variances increased with age and reached a maximum at about 30 months, whereas the maternal additive genetic (co)variances increased rapidly from birth and reached a maximum at weaning, and then decreased with age. Animal permanent environmental (co)variances increased with age from birth to 30 months with lower rate before 12 months and higher rate between 12 and 30 months. Maternal permanent environmental (co)variances changed little before 6 months but then increased slowly and reached a maximum at about 30 months. These results suggested that the contribution of maternal additive genetic and permanent environmental effects to growth variation differed from those of direct additive genetic and animal permanent environmental effects not only in expression time, but also in action magnitude. The phenotypic (co)variance estimates increased with age from birth to 36 months of age.

• 산경연구논집
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• 제12권8호
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• pp.33-39
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• 2021

Purpose: The influence of age on time preference is not identified in the usual cross-sectional analysis. This study aims to test whether age affects time preference after controlling for the effects of individual heterogeneity including cohort effects. Research design, data and methodology: Drawing on a nationally representative panel dataset of Indonesians, we estimate the effects of age on time preference after controlling for unobserved individual heterogeneity as well as potential cohort effects. We measure time preference exploiting information on two sets of multiple price lists: one for a one-year delay, and the other for a five-year delay. Results: When we controlled for time-invariant individual characteristics, including birth cohort effects in a fixed effects model, the older men and women were more patient in a linear fashion, particularly when the delay was longer. To highlight the importance of controlling for individual fixed effects, we repeated the specification without controlling for individual fixed effects in OLS or censored maximum likelihood regression; we found no relation between age and impatience in men or women and for a one or five-year delay. Conclusions: The older men and women are more patient, and time preferences are correlated with unobserved individual heterogeneity.

• Journal of Preventive Medicine and Public Health
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• 제53권3호
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• pp.198-204
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• 2020

Objectives: This study aimed to analyze the mortality of heart disease (HD), ischemic heart disease (IHD), and cerebrovascular disease (CeVD) through an age-period-cohort (APC) analysis. Methods: We used data on mortality due to cardiovascular disease from 1995 to 2018 in Japan, as determined by Vital Statistics. Age groups from 0 years to 99 years were defined by 5-year increments, and cohorts were defined for each age group of each year with a 1-year shift. We used Bayesian APC analysis to decompose the changes in the diseases' mortality rates into age, period, and cohort effects. Results: The period effects for all diseases decreased during the analyzed periods for both men and women. The cohort effects for men increased substantially in cohorts born from around 1940 to the 1970s for all types of cardiovascular diseases. The cohort effects of HD decreased in the cohorts born in the 1970s or later for both men and women. Regarding IHD and CeVD, either a non-increase or decrease of cohort effects was confirmed for cohorts born in the 1970s or later for men, but the effects for women showed a continuously increasing trend in the cohorts born in the 1960s or later. Conclusions: The cohort effects for IHD and CeVD showed increasing trends in younger generations of women. This suggests that preventive approaches against cardiovascular diseases are needed, particularly for women.

• Food Science and Biotechnology
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• 제16권3호
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• pp.404-408
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• 2007

In this study, we investigated the effects by age of long-tenn supplementation of Epimedium koreanum Nakai (EKN)-containing water on the in vivo antioxidant capacities of rats. All rats were reared in a conventional system, and none of the rats showed any signs of aversion to the EKN solution. Neither the mean nor maximum life spans of the rats were extended by long-tenn administration of the solution. The EKN extract caused decreases in the levels of serum thiobarbituric acid reactive substances in the rats. The activities of superoxide dismutase, catalase, and glutathione (GSH) peroxidase within the liver cytosol decreased with age in both the control and EKN-supplemented groups. GSH peroxidase activity, however, was higher at old age in the EKN-supplemented group. The activities of GSH reductase and GSH-S-transferase, and the levels of free-sulfhydryl (SH) and total-SH group gradually decreased with age in both groups. However, there was some tendency for higher levels in the EKN supplemented group at a corresponding age. These results indicate that long-tenn supplementation of EKN water extracts alone does not exhibit discernible adverse effects in rats, and has some enhancing effects on the antioxidant capacities of the blood and liver, but it does not have life-prolonging effects.

• 한국식생활문화학회지
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• 제22권3호
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• pp.309-314
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• 2007

The purpose of this study was to measure the effects of attitude toward fish eating, Health involvement and convenience on the relationship between fish consumption and age. A total of 235 questionnaires were completed. Structural equation model was used to measure the causal relationships between constructs. Results of the study demonstrated that the structural equation analysis result for the data also indicated excellent model fit. The effects of age on involvement and convenience were statistically significant. The effects of age on attitude and consumption was not statistically significant. As expected, the involvement had a significant effect on attitude and consumption. The attitude and convenience had a significant effect on consumption. The effect of involvement on convenience was not statistically significant. Moreover, the attitude, involvement and convenience played a mediating role in the relationship between consumption and age. The involvement played a mediating role in the relationship between attitude and age. The involvement played no mediating role in the relationship between convenience and age. The attitude and convenience played no mediating role in the relationship between consumption and involvement.

• Journal of Nutrition and Health
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• 제27권1호
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• pp.46-52
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• 1994

Recently it is reported that RBC membrane fluidity decreases and RBC calcium levels increase with age. The aim of this study was to analyze changes in lipid and calcium metabolism with age, and to seek relationship of diet and metabolism. With clinically normal Korean adults(male 60, female 63), this study was carried out in three phases : 1) to analyze fatty acid percentage of RBC membrane, 2) to analyze calcium levels of RBC with age, and 3) to compare the effects of dietary fatty acid intake on blood fatty acid profiles. The results are as follows : The P/S ratio of RBC membrane fatty acid decreased with age. The RBC calcium content increased according to age, with women having a higher level than men. The higher intake groups of linolenic acid(C18:3) has statistically higher serum linolenic acid levels. But dietary effects of membrane fatty acid were not found. Therefore, the further research to seek the possible relationship of diet and membrane fatty acid should be continued.

• Archives of Pharmacal Research
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• 제19권6호
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• pp.462-468
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• 1996

The present study was undertaken to investigate the effects of age on angiotensin II (AII) response and antagonistic activity of losartan using aortic rings and liver homogenates from rats ranging in age from 0.7 to 20 months. Whether the endothelium was present or not, the maximum contractile response to AII decreased with age. Removal of the endothelium enhanced AII-induced maximum contraction and these endothelial effects seemed to be due to endothelium-derived relaxing factor (EDRF) in all ages. Equilibrium binding studies demonstrated an age-related decrease in maximum binding $(B_{max})$ with little change in binding affinity $(K_d)$. In rat aorta, the extent of losartan-induced parallel shifts $(K_B)$ in AII concentration-response curves was not significantly different between ages. In addition, $IC_{50}$ value of losartan in competition binding was not changed with age in rat liver homogenates. These results suggest that the potency of losartan is not altered with age in rat aorta and liver, although AII-induced contractile response and the maximum AII binding decreased significantly with age.