Showing papers by "Korea University published in 1993"

International Comparisons of Educational Attainment

Abstract: Many theories of economic growth stress the role of human capital in the form of education, but empirical studies have been hampered by inadequate data. We describe a data set on educational attainment that we have constructed for 129 countries over five-year periods from 1960-1985. We use census/survey information to fill over 40% of the cells, and we use school enrollment figures in a perpetual-inventory framework to fill the remainder. The data refer to male and female attainment of the adult population at four levels: no-schooling. primary. secondary, and higher. We also provide a rough breakdown into incomplete and complete attainment at the three levels of schooling. We then take account of cross-country variations in the durations of schooling at each level to provide figures on total years of attainment.

Losers and Winners in Economic Growth

Abstract: For 116 countries from 1965 to 1985, the lowest quintile had an average growth rate of real per capita GDP of -1.3%, whereas the highest quintile had an average of 4.8%. We isolate five influences that discriminate reasonably well between the slow and fast-growers: a conditional convergence effect, whereby a country grows faster if it begins with lower real per capita GDP relative to its initial level of human capital in the fOnTIS of educational attainment and health; a positive effect on growth from a high ratio of investment to GDP (although this effect is weaker than that reported in some previous studies); a negative effect from overly large government; a negative effect from government-induced distortions of markets; and a negative effect from political instability. Overall, the fitted growth rates for 85 countries for 1965-85 had a correlation of 0.8 with the actual values. We also find that female educational attainment has a pronounced negative effect on fertility, whereas female and male attainment are each positively related to life expectancy and negatively related to infant mortality. Male attainment plays a positive role in primary-school enrollment ratios, and male and female attainment relate positively to enrollment at the secondary and higher levels.

Radiological findings of human fascioliasis

Abstract: Fasciola hepatica is a trematode of herbivorous mammals. Humans are accidentally infected by the ingestion of water or raw aquatic vegetables contaminated with the metacercaria. Radiological findings of six patients with fascioliasis (five hepatic fascioliasis, one biliary fascioliasis) were analyzed. The diagnosis was based on serologic testing and/or histopathologic findings of eosinophilic abscess in five patients and identification of the adult worm in one patient. The characteristic radiological features of hepatic fascioliasis were (1) cluster of microabscesses arranged in tract-like fashion (burrow tract), (2) subcapsular location of the hepatic lesions, and (3) very slow evolution of the lesion on follow-up examinations. In biliary fascioliasis, there were multiple conglomerated filling defects in the common bile duct. The authors believe that the demonstration of these features, together with peripheral eosinophilia or eosinophilic aspirate from the hepatic lesion, is very helpful in making the correct diagnosis.

Exact quantum theory of a time-dependent bound quadratic Hamiltonian system.

Abstract: Using the path-integral method, the propagator, the wave function, and the expectation values are evaluated explicitly for a time-dependent bound quadratic Hamiltonian system. We also have derived the relation between the wave function and a dynamical invariant which determines whether or not the system is bound. The expectation value of the quantum-mechanical invariant obeys the uncertainty relation with an auxiliary condition as the solution of the classical equation of the system.

Effect of Clonorchis sinensis infection and dimethylnitrosamine administration on the induction of cholangiocarcinoma in Syrian golden hamsters

Abstract: The study was carried out to observe the effects of Clonorchis sinensis infection on induction of cholangiocarcinoma in Syrian golden hamsters to which 15 ppm dimethylnitrosamine (DMN) solution was administered for 8 weeks. The histopathological changes of the bile duct and liver cells were observed at the 11th week. In six of 8 hamsters (75%) which were treated with DMN and then infected with C. sinensis, the livers developed cholangiocarcinoma at 10 weeks after the infestation of C. sinensis. The features of cholangiocarcinoma lesions were adenomatous or papillary hyperplasia of the bile duct epithelia showing distinct anaplastic changes with mucinous cell metaplasia and necrotic area. In the hamsters which received either DMN or C. sinensis alone, the livers showed only hyperplastic changes of the bile duct epithelial cells. It was suggested that C. sinensis infection and DMN administration could be a synergism on the development of cholangiocarcinoma in Syrian golden hamsters.

Regional expression and chromosomal localization of the delta opiate receptor gene

Abstract: The delta opiate receptor gene has been cloned from the mouse neuroblastoma-rat glioma hybrid cell NG108-15. The clone that we isolated is apparently identical to that reported by Evans et al. [Evans, C. J., Keith, D. E., Jr., Morrison, H., Magendzo, K. & Edwards, R. H. (1992) Science 258, 1952-1955] and essentially identical with that of Kieffer et al. [Kieffer, B. L., Befort, K., Gaveriaux-Ruff, C. & Hirth, C. G. (1992) Proc. Natl. Acad. Sci. USA 89, 12048-12052]. We have found full-length transcripts of the gene in mouse brain but in no other tissues examined. Within the brain the gene is expressed at low levels in many regions but transcripts are found in particularly large amounts in the anterior pituitary and pineal glands. Since these tissues are located outside the blood-brain barrier, opioid peptides easily can reach receptors in these areas from the blood. The gene, which is present as a single copy, has been mapped to the distal region of mouse Chromosome 4.

Enigmatic double-stranded RNA in Japonica rice.

Abstract: We have found a linear, 16 kb, double-stranded RNA (dsRNA) in symptomless Japonica rice (Oryza sativa L.) that is not found in Indica rice (Oryza sativa L.). The dsRNA was detected in every tissue and at every developmental stage, and its copy number was approximately constant (about 20 copies/cell). Double-stranded RNA was also detected in two strains of Oryza rufipogon (an ancestor of O. sativa). Hybridization experiments indicated that the dsRNA of O. rufipogon was homologous but not identical to that of O. sativa. The sequence of about 13.2 kb of the dsRNA was determined and two open reading frames (ORFs) were found. The larger ORF (ORF B) was more than 12 351 nucleotides long and encoded more than 4 117 amino acid residues.

Production of Two Single-Λ Hypernuclei by Ξ- Capture

Abstract: The S= −2 hypernuclear states formed through (K − , K + ) reactions have been studied by using the 1.66 GeV/c K − beam provided by KEK Proton Synchrotron. Investigation has been done on the stars due to the capture of the ξ − hyperons at rest in nuclear emulsion, which hyperons were produced in (K − , K + ) reactions. We observed a clear case of an absorption of ξ − hyperon at rest by a nucleus followed by a back-to-back emission of two single-Λ hypernuclei

Cloning of a cDNA encoding bovine mitochondrial NADP+-specific isocitrate dehydrogenase and structural comparison with its isoenzymes from different species

Abstract: Mitochondrial NADP(+)-specific isocitrate dehydrogenase (IDP) was co-purified with the pyruvate dehydrogenase complex from bovine kidney mitochondria. The determination of its N-terminal 16-amino-acid sequence revealed that it is highly similar to the IDP from yeast. A cDNA clone (1.8 kb long) encoding this protein was isolated from a bovine kidney lambda gt11 cDNA library using a synthetic oligodeoxynucleotide. The deduced protein sequence of this cDNA clone rendered a precursor protein of 452 amino-acid residues (50,830 Da) and a mature protein of 413 amino-acid residues (46,519 Da). It is 100% identical to the internal tryptic peptide sequences of the autologous form from pig heart and 62% similar to that from yeast. However, it shares little similarity with the mitochondrial NAD(+)-specific isoenzyme from yeast. Structural analyses of the deduced proteins of IDP isoenzymes from different species indicated that similarity exists in certain regions, which may represent the common domains for the active sites or coenzyme-binding sites. In Northern-blot analysis, one species of mRNA (about 2.2 kb for both bovine and human) was hybridized with a 32P-labelled cDNA probe. Southern-blot analysis of genomic DNAs verified simple patterns of hybridization with this cDNA. These results strongly indicate that the mitochondrial IDP may be derived from a single gene family which does not appear to be closely related to that of the NAD(+)-specific isoenzyme.

Magnetic properties of Pd/Co multilayer films studied by Hall effect

Abstract: The magnetic properties and Hall effects of Pd/Co multilayer films fabricated by thermal evaporation have been studied using the Hall hysteresis loop measurement. The polarity of the Hall hysteresis loops of Pd/Co multilayer changed between 4 and 5 monolayers (ML) of Pd. It was speculated that the reason for this phenomena is the change of the position of Fermi level of 3d band in Pd/1Co multilayer from lower half of the band to upper half of the band depending on the Pd thickness. The Hall resistivities as a function of Pd thickness were found to oscillate and the period of oscillation was about 5 ML of Pd. The change of saturation magnetization as a function of Pd thickness reflected the oscillatory behavior up to 7 ML of Pd and the enhanced Co moments were observed in the film with 4 or thicker ML of Pd.

Modeling of supercritical-fluid phase-equilibria using a new nonrandom lattice-fluid theory

Abstract: Experimental data for equilibrium solubility of biochemical substances such as stearic acid, oleic acid, triolein, and tristearin in supercritical carbon dioxide are measured. The experimental data and others in the literature are modeled by a newly formulated nonrandom lattice-fluid theory equation-of-state. The model is rigorously tested for its applicability to model supercritical-fluid phase-equilibria using a single binary interaction parameter for systems containing molecules of arbitrary size and shape of SCF-liquid equilibria for 27 binary systems, SCF-solid equilibria for 16 binary systems, SCF-polymer equilibria for 4 systems, and of 6 ternary mixtures for a wide range of temperature and pressure.

Cancer of the stomach: A review of two hospitals in Korea and Japan

Abstract: The records of 525 patients with primary adenocarcinoma of the stomach treated at Korea University Hospital (K.U.H.), Seoul, Korea, and 1,932 patients treated at National Cancer Center Hospital (N.C.C.), Tokyo, Japan, over a 7-year period were reviewed to study biologic characteristics and treatment results in the two hospitals. More than 70% of the patients were 41 to 70 years old in both hospitals, though K.U.H. had more younger patients and N.C.C. had more older patients. Comparison in regard to clinicopathologic features showed significant differences in type of cancer, tumor size, depth of invasion, lymph node metastasis, stage, and histologic type. Such a difference mostly was due to a greater frequency of early gastric cancer in N.C.C. patients (51.2%) than in K.U.H. patients (19.0%). Patients of K.U.H. were more likely to have advanced cancer, large invasive tumors, a higher percentage of lymph node metastasis, a higher stage, and more undifferentiated tumors. The 5-year survival rate of all resected cases was 69.5% in N.C.C. and 54.2% in K.U.H. (p>0.05). Those factors which showed a significant difference in clinicopathologic features did not affect the survival difference between the two hospitals except in stage IIIb and signet-ring-cell cancer. The 5-year survival rate for stage IIIb was 18.0% in K.U.H. and 36.8% in N.C.C. It would seem that survival difference in stage IIIb related to extensive lymph node dissection in N.C.C. Survival difference in signetring-cell gastric cancer (31.2% in K.U.H. and 91.0% in N.C.C.) was related to the fact that 79.1% of signet-ring-cell gastric cancer patients in N.C.C. had early gastric cancer. This present study once again demonstrates the importance of early detection in the treatment of gastric cancer and suggests that gastric cancer of two countries is not different.

An outbreak of Heinz body positive hemolytic anemia in chronic hemodialysis patients.

Abstract: During the four month period, from December 1988 to March 1989, there was an outbreak of Heinz body positive hemolytic anemia in 34 patients undergoing hemodialysis in a 500-bed hospital, Seoul, Korea. The episodes of hemolysis were not reduced by changing the charcoal column and reverse osmosis system, or by adding ascorbic acid to the dialysate. The concentrations of nitrate, copper, aluminum and zinc in the treated water were all within the standards for hemodialysis. The chloramine concentration of the treated water was over 0.6 mg/L, markedly exceeding the allowable level of 0.1 mg/L. This high level of chloramine was proved to be due to the contamination of the water source by raw sewage. After we changed the source of water supply to another, no more episodes of hemolytic anemia occurred. It is concluded that chloramine is one of the major contaminants causing dialysis-induced hemolytic anemia and regular determinations are necessary, especially during winter and dry seasons.

Measurement of pH at elevated temperatures using the optical indicator acridine

Abstract: A new method of measuring the pH of high-temperature aqueous solutions using optical indicators was developed. The absorbance spectrum of acridine changes as a function of pH, allowing its use as an optical indicator for pH. The pKa of acridine were experimentally determined in KOH-AcOH pH-buffer solutions at temperatures from 5 to 250°C at vaporsaturated pressures: $$pKa = 5.62 + 1158{\text{ }}/{\text{ }}T{\text{ - }}0.7168{\text{ }}lnT$$ where T is in Kelvin. The technique is demonstrated by experimentally determining the pKa of benzoic acid at temperatures up to 250°C where the result was $$pKa{\text{ }}(benzoic{\text{ }}acid) = {\text{ - }}60.67 + 3069{\text{ }}/{\text{ }}T{\text{ }} + {\text{ }}9.5542{\text{ }}lnT$$

Hadronic energy distributions in deep-inelastic electron-proton scattering

Abstract: This paper presents energy distributions of the hadronic system produced in neutral-current electron-proton deep-inelastic scattering at a centre of mass energy of 296 GeV. Comparison of the results with QCD Monte Carlo models shows that QCD radiation has a strong influence on the characteristics of the final state. The data are reasonably reproduced by the Lund model based on a matrix element calculation in first order ofα s , followed by appropriate parton showers, as well as by the colour dipole model. The HERWIG parton shower model also gives a reasonable representation of the data. Neither the first order matrix elements alone nor the Lund parton shower model, without the matrix element calculation, reproduce the data.

Mineralogic, fluid inclusion, and stable isotope evidence for the genesis of carbonate-hosted Pb-Zn(-Ag) orebodies of the Taebaek Deposit, Republic of Korea

Abstract: The Taebaek Pb-Zn(-Ag) deposit of the Yeonhwa I mine, the largest Pb-Zn producer in Korea, occurs as chimney-shaped carbonate-sulfide vein orebodies developed in Cambro-Ordovician limestones and shales. Compared with other deposits (the Bonsan and Dongjeom) of the Yeonhwa I mine, the Taebaek deposit is characteristically skarn free and more rich in lead and silver. These characteristics suggest that the Taebaek deposit formed farther from a deep, hidden, associated igneous body. A K-Ar date of alteration sericite indicates that the mineralization at Taebaek took place during Late Cretaceous times (75 Ma). Four stages of ore deposition have definite sulfide assemblages: stage I, hexagonal pyrrhotite + arsenopyrite + native bismuth; stage II, pyrite + sphalerite + arsenopyrite; stage III, monoclinic pyrrhotite + sphalerite + galena + electrum + Ag minerals; and stage IV, barren calcite. Later stages of mineralization occur at higher (shallower) portions of each orebody, indicating that the locus of mineralization migrated toward higher levels with increasing paragenetic time.Fluid inclusion data indicate that temperatures and salinities of ore fluids progressively decreased with time (380 degrees -250 degrees C and up to 8 wt % NaCl equiv during stage II, and 305 degrees - 180 degrees C and down to 0 wt % NaCl equiv during stage III), mainly due to progressive mixing with cooler and more dilute meteoric waters. Fluid inclusion data and geologic arguments indicate that pressures during the mineralization were in the range of 210 to 420 bars. Thermochemical considerations indicate the activity of H (super +) decreased when fluids became equilibrated with host limestones, which resulted in a pH change (from about 5 to 7) and decreases in f (sub S 2 ) and f (sub O 2 ) . The pH increase, combined with a decrease in temperature, was responsible for the spatial and temporal variations of iron sulfides and ore precipitation.The delta 34 S values of ore sulfides have a narrow range between 1.6 and 5.3 per mil. The calculated delta 34 S (sub Sigma S) values of ore fluids are constant at 3.5 to 4 per mil, indicating a deep-seated igneous source of sulfur. The delta 13 C values of carbonates in ores range between -7.2 and -5.5 per mil and are considerably more negative than those (-1.9 to +0.9ppm) of the host lime-stones. It is likely that carbon in the ore fluids was a mixture of deep-seated magmatic carbon and limestone-derived carbon. Oxygen and hydrogen isotope studies revealed that the delta 18 O and delta D values of waters in ore fluids decreased gradually with time from +9.8 and -68 per mil (stage II) to +1.9 and -95 per mil (stage IV), respectively. This indicates that magmatic water was important during the early zinc mineralization but was progressively replaced by meteoric water during the later lead and silver mineralization.

Genetic environment of germanium-bearing gold-silver vein ores from the Wolyu mine, Republic of Korea

Abstract: The Wolyu mine is one of the largest vein-type gold-silver-bearing epithermal systems in the Youngdong district and is the first gold-silver deposit in Korea found to contain significant germanium, in the form of argyrodite (Ag8GeS6). Mineralized veins (78.9 ± 1.2 Ma) crosscutting Late Cretaceous hostrock tuff and quartz porphyry (81.5 ± 1.8 Ma) consist of three stages of quartz and carbonates, the first of which contains pyrite, basemetal sulfides and Au-Ag-minerals. Stage I Au-Ag-Ge-mineralized veins show a systematic variation of mineral assemblage with time: (1) quartz + pyrite; (2) quartz + pyrite + sphalerite + electrum + argentite; (3) carbonate + quartz + sphalerite + electrum + argentite; (4) carbonate + native silver + argentite + Ag-sulfosalts + argyrodite + sphalerite. Calculated values of temperature and sulfur activity are: assemblage (1), 360-280°C and 10−7-10−10; (2), 280-210°C and 10−10-10−14; (3), 210-180°C and 10−14-10−16; (4), 180-155°C and 10−17-10−18. These data, the frequent association of gold with sulfides, and the abundance of pyrite in alteration zones indicate that decreasing sulfur activity and cooling were important in triggering gold deposition. Hydrogen and oxygen isotope compositions of ore fluids display a systematic variation with increasing time. Within the main Ag-Au-Ge mineralization, δD and δ 18O values decrease with the transition from quartz to carbonate deposition (from -78 and −2.8% to −90 and −8.7%., respectively), indicating increasing involvement (mixing) of less evolved meteoric water which resulted in progressive cooling and dilution of ore fluids in the shallow (≈ 370–600 m) Wolyu epithermal system.

Mycobacterium fortuitum Peritonitis Associated with Continuous Ambulatory Peritoneal Dialysis

Abstract: Runyon group IV atypical mycobacteria, Mycobacterium fortuitum, is an environmental organism and is capable of producing a variety of clinical infections such as cutaneous infection, abscess and pulmonary and ocular infection. Rarely, it has been a documented cause of peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD). We report a case of M. fortuitum peritonitis in a patient undergoing CAPD and emphasize the importance of mycobacterial cultures in patients with CAPD-associated peritonitis whose routine culturing yields no organisms repeatedly.

A prototype filter design approach to pyramid generation

Abstract: This paper presents a technique for image pyramid generation, in which the reduction (expansion) factor between layers is any rational number M/L. The image pyramid generation is modeled as an interpolation and filtering followed by a decimation. The model enables frequency domain analysis of the image pyramid, as well as convenient design of the generating kernels. L(M) generating kernels are necessary to produce an image pyramid with reduction (expansion) factor M/L(L/M). A polyphase filter network scheme is used where the L(M) generating kernels can be produced by sampling one prototype low-pass filter with cutoff frequency at omega = pi /max(M,L). Using these polyphase filters, the frequency content of pyramid image decompositions can be adjusted with great flexibility. A systematic procedure is presented here for specifying the relative positions of spatial samples in successive pyramid levels-a complication that arises when generalizing from integer reduction factors to rational factors. Two types of low-pass filters are employed in this work for the prototype filter design: a binomial filter and an FIR linear phase filter. Illustrative examples are presented. >