• 한국건축시공학회지
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• 제14권1호
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• pp.110-117
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• 2014

본 연구에서는 양생온도변화에 따른 자기수축의 예측을 위하여 FA 및 SF를 치환한 시멘트모르타르를 대상으로 자기수축변화를 측정하고 이를 등가재령방법으로 해석하고자 하였다. 이를 위해 수화반응의 온도민감도를 고려하는 Ea의 변화에 따라 지수함수모델을 이용하여 자기수축 해석을 실시하였는데, 경화단계의 $E_a$를 이용할 경우 응결단계의 $E_a$를 사용한 경우보다 정확한 해석이 가능한 것으로 나타났는데, 이는 경화의 전단계에 걸친 수화의 온도민감도 영향을 반영한 $E_a$값에 기인된 결과로 사료된다.

• 한국건축시공학회지
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• 제20권5호
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• pp.409-416
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• 2020

본 연구는 W/C 50%의 일반강도 조건에서 OPC, FA 및 BS 시멘트의 종류를 변화시켜 콘크리트의 강도 증진 성상을 한랭기 온도의 4~17℃의 평균 양생온도에서 검토하고, 등가재령에 의한 강도 해석모델을 이용하여 강도 증진 해석을 수행하고, 기온저하에 따른 기온보정강도를 제안하고자 하였다. 본 실험의 결과 등가재령을 이용하여 Plowman 모델식으로 강도증진을 해석하였고, 대체로 양생온도가 낮을수록 강도증진이 지연되는 경향을 나타내었다. 이에 양생온도 저하에 따른 강도보정을 3MPa 단위로 실시하였고, 이를 토대로 배합강도 결정시 결합재 종류 및 관리재령별 기온보정강도(T_n)을 제안하였다.

• 대한간호학회지
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• 제5권2호
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• pp.29-37
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• 1975

The purpose of this study was to measure the extent of stress existing in hospitalized patients which might play an important part in delaying recovery of patients. The study was conducted July l0th through 16th, 1975; a total of 146 patients from 2 general hospitals in Seoul were sampled. Questionnaire, formulated by the researcher, were used to gather necessary information concerning stress in accordance with the physical, psychological, economical and social variables. Data were analysed by mean stress score, and the significances were tested by Critical Ratio. The results were as follows ; 1. No significant difference was revealed in accordance with sex, however, male patients showed higher stress scores on the economic variables. 2. No. significant difference was apparent in accordance with marital status, however, the unmarried showed a tendency of higher stress scores at all variables. 3. Significant difference was revealed between the age group of 35-49 years and that of over 50 years; the age group of 18-34, and 35-49 years showed higher stress scores. 4. No. significant difference was revealed in accordance with previous experience of hospitalization, however, the group with previous experience tends to show higher stress scores in all variables. 5. No significant difference was revealed in accordance with the types of admission, however, group admitted on emergency showed higher stress scores compared to the group admitted plained in advance at social and economic variables. 6. No significant difference was revealed in accordance with the length of hospitalization, however, tendencies were apparent that the longer the length of hospitalization, the lower the mean stress scores.

• 생물정신의학
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• 제21권1호
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• pp.1-13
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• 2014

Normal aging causes changes in the brain volume, connection, function and cognition. The brain changes with increases in age and difference of gender varies at all levels. Studies about normal brain aging using various brain magnetic resonance imaging (MRI) variables such as gray and white matter structural imaging, proton spectroscopy, apparent diffusion coefficient, diffusion tensor imaging and functional MRI are reviewed. Total volume of brain increases after birth but decreases after 9 years old. During adulthood, total volume of brain is relatively stable. After 35 years old, brain shrinks gradually. The changes of gray and white matters by aging show different features. N-acetylaspartate decreases or remains unchanged but choline, creatine and myo-inositol increase with aging. Apparent diffusion coefficient decreases till 20 years old and then becomes stable during adulthood and increase after 60 years old. Diffusion tensor properties in white matter tissue are variable during aging. Resting-state functional connectivity decreases after middle age. Structural and functional brain changes with normal aging are important for studying various psychiatric diseases such as dementia, schizophrenia and bipolar disorder. Our review may be helpful for studying longitudinal changes of these diseases and successful aging.

• Ocean and Polar Research
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• 제24권3호
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• pp.197-205
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• 2002

Total magnetic field and high-resolution bathymetric data were collected over nine seamounts to the northwest of the Marshall Islands in the western Pacific. Magnetic parameters including inclination and declination were calculated from the magnetic anomalies using inversion algorithm of Plouff (1976), and a corresponding paleomagnetic pole was determined with the magnetic parameters. The paleomagnetic poles determined in this study were compared with the previous apparent polar wander path (APWP) of Pacific plate. Most seamounts of the study area have normal polarity. The study reveals that all nine seamounts in the study area formed in the southern hemisphere during the Cretaceous based on their comparison with the APWP of Pacific plate. The ages estimated from paleomagnetic poles can be divided by age into three groups: the oldest (OSM1 and OSM3), middle age (OSM2, OSM4, and 6-2), and the youngest (OSM5-1, 5-2, 5-3, and 6-1). The fermer two groups and the latter seem to be coincident with two distinct pulses of Cretaceous volcanic activity (115-90 Ma and 83-65 Ma). As a whole the seamounts at southwest of the study area are older than at those northeast.

• Asian-Australasian Journal of Animal Sciences
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• 제31권1호
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• pp.91-97
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• 2018

Objective: A 14-d trial was conducted to determine the effects of feeding corn naturally contaminated with aflatoxin $B_1$ ($AFB_1$) on growth performance, apparent ileal digestibility, serum hormones levels and gene expression of $Na^+$, $K^+-ATPase$ in ducklings. Methods: A total of 704 ducklings were blocked on the basis of sex and body weight (BW), and then allocated randomly to one of the following two treatments: i) CON, basal diet and ii) $AFB_1$, diets with 100% of normal corn replaced with $AFB_1$ contaminated corn. There were 22 pens per treatment and 16 birds per pen. The concentration of $AFB_1$ was 195.4 and $124.35{\mu}g/kg$ in the contaminated corn and $AFB_1$ diet, respectively. Results: The $AFB_1$ decreased average daily gain, average daily feed intake, d 7 BW, final BW in the whole trial, and feed conversion ratio (FCR) during d 8 to 14 and d 1 to 14 by 10% to 47% (p<0.05), while FCR during d 1 to 7 was increased (p<0.05). $AFB_1$ did not affect mortality to 7 d of age, and then increased to 5.8% from 8 to 14 d of age (p<0.01). Apparent ileal gross energy digestibility was reduced by $AFB_1$, whereas apparent ileal digestibility of dry matter, nitrogen, and amino acid was improved (p<0.01). Feeding $AFB_1$ diets increased serum concentration of leptin and insulin-like growth factors-1 (IGF-1) (p<0.05), but had no effect on neuropeptide Y, ghrelin, cholecystokinin-8 or insulin (p>0.05). Dietary treatments did not influence relative expression of jejunal $Na^+$, $K^+-ATPase$ gene (p>0.05). Conclusion: Taken together, feeding corn naturally contaminated with $AFB_1$ reduced growth performance, improved apparent ileal digestibility, and affected serum leptin and IGF-1 in ducklings from d 1 to 14.

• Journal of Nutrition and Health
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• 제30권8호
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• pp.911-919
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• 1997

The purpose of this research was to investigate the effect of caffeine levels on calcium utilization in rats of different age and sex. Calcium utilization was compared in rats of different age(4 weeks and 10 months) and sex that were fed various levels of caffeine (0, 3.5, and 7mg/100g body weight) for 3 weeks. There was no significant difference in feed intake, serum calcium level, and ash content in tibia among the groups. Fecal calcium excretion was lower in young rats than in adults, Urinary calcium excretion significantly higher in the caffeine groups than that in the no-caffeine group. Daily retention and apparent absorbability of calcium in young rats were higher than those in adult rats. However, there was no significant difference among groups of different sex and caffeine levels. The results of this study suggest that caffeine consumption promotes urinary calcium excretion.

• 한국식물병리학회지
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• 제10권1호
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• pp.18-24
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• 1994

Multiplications and pathogenic reactions of different pepper and tomato strains of Xanthomonas campestris pv. vesicatoria were evaluated in the most upper leaves of pepper and tomato plants at different growth stages. Hypersensitive reactions were induced in mature pepper plants by inoculation with only the tomato strains but not with the pepper strains, suggesting the expression of age-related resistance in pepper plants. The age-related resistance also seems to be correlated with an apparent inability of the bacteria to multiply as extensively in mature as in young plants. No significant differences among the Korean and U. S. pepper cultivars tested were found in bacterial multiplication, irrespective of bacterial stain or plant growth stage. Korean tomato cultivars tested also were highly susceptible to either tomato or pepper strains during the development of tomato plants.

• Clinical and Experimental Pediatrics
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• 제59권9호
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• pp.347-354
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• 2016

An apparent life-threatening event (ALTE) is defined as the combination of clinical presentations such as apnea, marked change in skin and muscle tone, gagging, or choking. It is a frightening event, and it predominantly occurs during infancy at a mean age of 1-3 months. The causes of ALTE are categorized into problems that are: gastrointestinal (50%), neurological (30%), respiratory (20%), cardiovascular (5%), metabolic and endocrine (2%-5%), or others such as child abuse. Up to 50% of ALTEs are idiopathic, where the cause cannot be diagnosed. Infants with an ALTE are often asymptomatic at hospital and there is no standard workup protocol for ALTE. Therefore, a detailed initial history and physical examination are important to determine the extent of the medical evaluation and treatment. Regardless of the cause of an ALTE, all infants with an ALTE should require hospitalization and continuous cardiorespiratory monitoring and evaluation for at least 24 hours. The natural course of ALTEs has seemed benign, and the outcome is generally associated with the affected infants' underlying disease. In conclusion, systemic diagnostic evaluation and adequate treatment increases the survival and quality of life for most affected infants.

• Communications for Statistical Applications and Methods
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• 제28권2호
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• pp.119-134
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• 2021

Lung cancer is one of the leading causes of cancer deaths in the world. Investigation of mortality rates is pivotal to adequately understand the determinants causing this disease, allocate public health resources, and apply different control measures. Our study aims to analyze and forecast age-specific US lung cancer mortality trends. We report functions of mortality rates for different age groups by incorporating functional principal component analysis to understand the underlying mortality trend with respect to time. The mortality rates of lung cancer have been higher in men than in women. These rates have been decreasing for all age groups since 1990 in men. The same pattern is observed for women since 2000 except for the age group 85 and above. No significant changes in mortality rates in lower age groups have been reported for both gender. Lung cancer mortality rates for males are relatively higher than females. Ten-year predictions of mortality rates depict a continuous decline for both gender with no apparent change for lower age groups (below 40).