• Journal of Korean Society of Forest Science
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• v.101 no.1
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• pp.62-68
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• 2012

We have investigated needle life span, photosynthetic pigment and nitrogen allocation pattern in the needle of Picea jezoensis in the three populations (Gyebangsan, Deogyusan and Jirisan) to find out growth environmental condition which needs the strategy development of conservation and restoration against population decline. Needle survival rate was the highest in Gyebangsan (87.0%) and the lowest in Jirisan (71.6%), and it decreased with the increase of needle age. Needle chlorophyll a and b in Deogyusan and Jirisan showed higher content in older needle, but chlorophyll content in Gyebangsan was the highest in 2-year-old needle. Carotenoid content was the highest in the needle in Gyebangsan, and it increased along with needle age. Chlorophyll a/b ratio showed the highest value in Jirisan and the lowest value in Gyebangsan. Chlorophyll/carotenoid ratio decreased with needle age, Needle nitrogen content was the highest in Deogyusan (1.51%) and the lowest in Gyebangsan (1.40%), and the older needle had the lower content. In contrast, the highest chlorophyll/nitrogen ratio represented the oldest needle.

• Journal of the Korean earth science society
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• v.42 no.1
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• pp.11-38
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• 2021

Detrital zircon U-Pb dating of samples from the Baekseoktan (Iljik Formation), Mananjaam (Jeomgok Formation), and Sinseongri (Sagok Formation) geosites in the Cheongsong Global Geopark were carried out to estimate the depositional age and provenance of the Hayang Group in the Gyeongsang Basin. In the Iljik Formation, Jurassic and Triassic zircons are dominant with minor Precambrian zircons, with no Cretaceous zircon. In contrast, the Jeomgok and Sagok formations show very similar age distributions, which have major age populations of Cretaceous, Jurassic, and Paleoproterozoic ages. The weighted mean ages of the youngest zircon age groups of the Jeomgok and Sagok formations are 103.2±0.3 and 104.2±0.5 Ma, respectively. Results suggest that the depositional ages of the Jeomgok and Sagok Formations are Albian. The detrital zircon age spectra indicate a significant change in provenance between the Iljik and Jeomgok formations. The sediments of the Iljik Formation are thought to have been supplied from nearby plutonic rocks. However, the Jeomgok and Sagok sediments are interpreted to have been derived from relatively young deposits of the Jurassic accretionary complex located in southwest Japan.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.3
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• pp.215-233
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• 2022

The zircon U-Pb and trace element analyses were performed for banded gneiss in the Euiam gneiss complex, central Gyeonggi Massif. An age of detrital zircon shows predominant age peaks at ca. 2500-2480 Ma with numerous ages ranging from Siderian to Rhyacian period. The youngest age peak of detrital zircon constrains the maximum deposition age of protolith of banded gneiss at ca. 2070 Ma. Meanwhile, the zircon rim yielded metamorphic age of ca. 1966 ± 39 Ma ~ 1918 ± 13 Ma. Based on the error range, degree of discordancy, and value of mean squared weighted deviation, we considered that the age of 1918 ± 13 Ma is the most reasonable age indicating the timing of metamorphism for banded gneiss. The zircon rims yield Ti-in-zircon crystallization temperature of 690-740℃. Therefore, we suggested that there was a high-grade metamorphic event in the Gyeonggi Massif at ca. 1918 Ma which is older than the metamorphic event that occurred in the Gyeonggi Massif during ca. 1880-1860 Ma.

• Korean journal of applied entomology
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• v.61 no.4
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• pp.549-554
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• 2022

Life table-related studies in insect ecology have been an interesting topic for insect researchers. Two calculation methods are commonly applied to estimate the intrinsic rate of natural increase (r_m) in the life table statistics. The first method is to estimate an approximate r_m by dividing the natural logarithm of the net reproductive rate (R₀) by mean generation time (T) (namely mean generation time-based method). Another approach is to apply the Lotka-Euler equation derived from the population growth equation of Lotka-Volterra to estimate accurate r_m using the maximum likelihood method (Lotka-Euler equation-based method). In the latter case, there is a difference in the estimated r_m value when the initial age class of the target cohort was set to "0" or "1", which confused the application. In this short review, a brief history of the calculation process of the life table was reviewed. It was again confirmed in the Lotka-Euler equation-based method that the form of $\sum\limits_{x=1}^{w}e^{-rx}l_xm_x=1$ should be applied to estimate r_m when the first age class was set to zero, while the form of $\sum\limits_{x=0}^{w}e^{-r(x+1)}l_xm_x=1$ when set to one.

• Journal of radiological science and technology
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• v.37 no.4
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• pp.267-272
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• 2014

It is well known that low body mass index and younger age are associated with high breast density. Mammographic dense breast has been reported both as a cause of false-negative findings on mammography and as an indicator of increased breast cancer risk. The purpose of this study was to evaluate the association between breast density and body mass index. Furthermore, we considered proper screening method of breast cancer in Korean women. The study was performed on 496 women who underwent health checkup in a university hospital. Age and body mass index were negatively associated with breast density respectively. In postmenopausal women, age and body mass index showed statistically significant association with breast density. Therefore, we should consider sensitive additional method for breast cancer screening especially in younger age and underweight women.

• Korean Journal of Childcare and Education
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• v.3 no.1
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• pp.39-56
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• 2007

The purpose of this study was to examine difference of Young Children's Self-Regulation by Mother's Verbal Control. To do so, The subject was composed of 146 3-, 4-, 5-year-old recruited from 5 child care centers in I city area And it utilized questionnaires to ask 146 mothers concerning Mother's Verbal Control and Young Children's Self-Regulation. The findings of this study were : First, the age and the gender of young children didn't affect the mother's verbal control. Second, the age of young children positively affected self decision and total self regulation total that is the subordinate area of self regulation. Third, use degree of mother's order and humanity verbal control divided high and low group up to the standard average value. As a result a low rank distribution of mother's verbal control positively affected. Forth, a result a low rank distribution of mother's verbal control positively affected self decision and behavior restrain and emotion and total self regulation total that is the subordinate area of self regulation.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.233-239
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• 2004

This study investigated the status of soft contact lens wear in college students. The results were as follows: 1. The most prevalent age of initial contact lens wear was 19 years or 20 years, with an age distribution in females from as early as 10 years to 20 years. 2. For almost all subjects, the test clinic for the contact lens wear assessment and purchase of the contact lenses was an optical shop. 3. The main advantage for most male subjects was use for sports, whereas most female subjects used contact lenses for cosmetic reasons. 4. The most common side-effects experienced due to contact lens wear were red eye, foreign body sensation, and eye pain. 5. The most frequently reported eye disease caused by contact lens wear was conjunctivitis, with only few subjects experiencing keratitis. 6. Following treatment for the side effects of contact lens wear, most subjects hoped to re-use the previous contact lenses, some subjects wanted to change to new contact lenses, and others subjects refused further contact lens wear.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.93-96
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• 2007

Research was taken its place in Dong wun elementary school in Gwang ju city. Subject ages were somewhere around 9 to 13. Among total number of 1,196, subjects with emmetropia were 384 people (32.1%), with 22.56% of 9 year old students, 16.01% of 10 year old student, 36.45% of 12 year old student, 39.11% of 13 year old. When age increases, the rate of emmetropia increase as well. Gender dependence of emmetropia rato was 31.07% for boys and 33.33% for girls, which proves girls with higher emmetropia ratio than boys. Among subjects with binocular vision acuity lower than 0.7, those require spectacles, only 37.5% of 9 years old students, 30.3% of 10 year old students, 44.64% of 12 year old students, and 30% of 9 year old students were wearing glasses. It shows that spectacle-wearing ratio is very low in spite of visual acuty lower than 0.7.

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.222-232
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• 2001

Secondary ion mass spectrometry (SIMS) uses focused high-speed primary ions to produce secondary ions from sample surface that are analyzed through a mass filter. SIMS is often called as ion microprobe, since it offers a micrometer-scale spatial resolution. Although the precision and accuracy of SIMS are not as good as many conventional mass spectrometers, it has several advantages such as small sample-size requirement, high spatial resolution and capability of in-situ analysis. In the field of geochemistry/cosmochemistry, SIMS is widely used for (1) stable isotope geochemistry of H, C, O, S, etc., (2) geochronology of U/Th-bearing minerals, (3) lateral distribution of trace elements in a mineral, and (4) discovery of presolar grains and investigation of their isotopic compositions.

• Clinical and Experimental Pediatrics
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• v.48 no.2
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• pp.174-177
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• 2005

Purpose : We evaluated children with Henoch-$Sch{\ddot{o}}nlein$ purpura(HSP) in terms of epidemiology and clinical characteristics. Methods : A total of 424 medical records of children with HSP admitted to The Catholic University of Korea, Daejeon St. Mary's Hospital, from 1987 to 2003 were retrospectively analyzed. Results : The mean annual number of cases was $25.1{\pm}7.9$ and no one year showed an outbreak. There was a steady number of patients throughout the year with a decrease during the summer season. The male-to-female ratio was 1.3 : 1 with the median age of the patients being 6-years-old. The age distribution showed a peak at age 6 in a bell-shaped distribution curve. Purpura was noted in 100 percent of the patients, gastrointestinal involvement in 53.8 percent, joint involvement in 40.8 percent, and renal involvement in 18.9 percent. Nephrotic syndrome occurred in 1 percent of all patients. Conclusion : The epidemiologic and clinical features of HSP were similar to those of other regions in Korea and foreign nations, irrespective of time.