• School Mathematics
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• v.15 no.1
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• pp.101-120
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• 2013

International comparative studies of students' performance in mathematics have shown that Korean students possess very negative attitudes toward mathematics, while they are ranked as one of the highest in the cognitive achievement of mathematics. This has prompted mathematics educators to seek for a way to improve the quality of mathematics education. In this context, this research has been conducted to investigate the learning style of Korean middle school students under the assumption that it is of essence to understand the characteristics of our students as mathematics learners. For the purpose, in-depth interview had been conducted and sixteen middle students participated in the interview. The students were chosen to represent the average group of their age-cohorts based on their performance in mathematics and their SES. The interview was designed as a semi-structured clinical interview. In the interview, the students were given mathematical tasks dealing with central themes in the domain of function. Each student was given about 30 to 50 minutes to solve the tasks. After an interviewee finished the tasks, s/he was asked to explained how s/he solved the tasks. The researchers asked additional questions to clarify the students' understanding of the mathematical themes in the tasks and to identify their strategies for learning mathematics. The analysis of the in-depth interview has primarily identified the characteristics of the students' understanding of the main themes in function and then has been extended to investigate their characteristic styles for learning mathematics. The analysis of the interview identified the learning styles of the students as 'inductive learning based on prototypical cases', 'repeated practice of exemplar mathematics problems', 'disengaged learning', and 'double standards in learning mathematics'. Based on the results of the analysis, this research presents the implications for the improvement of mathematics education.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.11
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• pp.1641-1648
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• 2015

This study was conducted to evaluate the effects of various protein sources (soybean meal, SBM; cottonseed protein, CSP; double-zero rapeseed meal, DRM) on the internal quality of refrigerated eggs. A total of 360 laying hens (32 wk of age) were randomly allotted to six treatment groups (five replicates per treatment) and fed diets containing SBM, CSP, or DRM individually or in combination with equal crude protein content (SBM-CSP, SBM-DRM, and CSP-DRM) as the protein ingredient(s). A $6{\times}3$ factorial arrangement was employed with dietary types and storage time (0 d, 2 wk, and 4 wk) as the main effects. After 12 wk of diet feeding, a total of 270 eggs were collected for egg quality determination. The egg Haugh unit (HU) in the CSP, SBM-DRM, and DRM groups were significantly lower than those in the SBM and SBM-CSP groups. The hardness and springiness of the cooked yolk in the CSP group were significantly higher than those in the other treatment groups. A lower HU, lower yolk index and higher albumen pH were observed in the DRM group compared to the SBM and SBM-CSP groups when the eggs were stored to 4 wk, and the HU was improved in the CSP-DRM group compared to the DRM group (p<0.05). Higher yolk hardness was observed in the CSP group compared to the other groups during storage (p<0.05), but the hardness of the cooked yolk in the SBM-CSP and CSP-DRM groups showed no difference in comparison to the SBM group. In conclusion, CSP may ameliorate the negative effects of DRM on the HU of refrigerated eggs, and SBM or DRM may alleviate the adverse effects of CSP on yolk hardness.

• Environmental and Resource Economics Review
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• v.20 no.3
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• pp.595-628
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• 2011

This study investigates the issues and suggests reform measures in applying CV methods to the Korea Development Institute's (KDI's) Preliminary Feasibility Test (PFT) of public projects. Most public projects on culture, science and environment evaluated under the PFT system belong to the category of "nonstandard" projects whose outputs are non-marketed, and CV is currently the main tool used for their benefit estimation. A careful discussion and investigation is recommended for the selection of target population, payment vehicle, and number of payment times. Operating expert reviews, focus group interviews, and pre-tests is highly recommended to reduce the potential bias involved in the CV studies. A single or double bounded dichotomous choice format is the most popular design of questionnaire, but we identify several undissolved issues in designing and implementing the format. Some other forms of inducing WTPs may still deserve our consideration. Various specifications of the WTP function need to be tried and tested based on their stability, in particular. Employing a nonparametric approach is also recommended. Treatments of 0 or negative WTPs and protest bids are shown to be the most serious issues that affect the estimation results significantly. We review diverse measures of handling those issues and summarize their advantages and shortcomings.

• Journal of Nutrition and Health
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• v.25 no.6
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• pp.429-449
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• 1992

The consumption of foods rich in TDF should not be associated with impaired mineral absorp-tion and long-term mineral status. In surveys of populations consuming high amounts of TDF e.g Third World populations and vegetarinas gross deficiencies in mineral nutrition have not been noted. If mineral status is low among these groups it is most likely caused by the inadequacy or imbalance of the diet and not by the TDF. The key word is interaction which should be inte-rpreted in dietary imbalances that produce nut-rient deficiencies. There are no strong data to support the concept that TDF inhibits mineral absorption through a binding chelation mechanism. Limited data sug-gest that positively charged groups on polymers such as chitosan and cholestyramine will decrease iron absorption in humans and animals. Because TDF does not contain positively charged groups future research should be directed at the possible role of protein consumed along with TDF and the combination of effects on mineral nutrition Phytic acid is acknowledged as a potent chela-tor of zinc. However its association with zinc and its propensity to lower Zn bioavaiability may enhance the absorption of other elements notably copper and iron. The importance of interactions among nutrients including TDF will gain addi-tional attention in the scientific community. Soluble and insoluble dietary fiber function di-fferently in the intestine. Insoluble fibers accele-rate movement through the intestine. Soluble die-tary fibers appear to regulated blood concentra-tions of glucose and cholesterol albeit by some unknown mechanism. In creased viscosity produ-ced by the SDF in the intestine may provide an explanation of how this class of polymers affects plasma glucose cholesterol and other nutrients. Employing a double-perfusion technique in the rat we demonstrated that viscosity produced by SDF will delay transfer of zinc into the circulatory system. This delayed absorption should not be interpreted as decreased utilization. A great deal of additional research is required to prove the importance of luminaly viscosity produced by SDF on slowing nutrient absorption or regulating bllod nutrient homeostasis. Increased intake of TDF in the total human diet appears desirable. A dietary intake of 35g/day should not be considered to have a negative effect on mineral absorption. It is important to educate people that an intake of more than 35g TDF/day may cause an imbalance in the diet that can adve-rsely affect mineral utilization. Acknowledgments. Appreciation is given to Dr. George V. Vahouny(deceased) who was intense a great competitor in and out of science and who gave the author inspiration Portions of this work were supported by the University of Missouri Ag-ricultural Station and by a grant from the Univer-rch Support Grant RR 07053 from the National Institutes of Health. Contribution of the Missouri Agriculatural Experiments Station Journal Series No. 10747.

• Journal of Yeungnam Medical Science
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• v.3 no.1
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• pp.87-94
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• 1986

Empyema thoracis following pneumonia, intra-abdominal pathology, trauma, and surgical procedure continues to be a source of major morbidity and mortality. Thirty seven adult and eleven pediatric patients with empyema thoracis were treated at the University of Yeungnam Medical Center from May 1983 to November 1986. Age distribution ranged from 6 months to 72 years and showed a double-peaked curve with the highest incidence between 36 and 65 years and below 15 years of age. There were male predominence in patients above 16 years of age. The most common predisposing factors was impaired consciousness due to either alcoholism or head injury. The causes of empyema were as follows: pneumonia 64.6%, lung abscess 6.4%, intraabdominal pathology 6.4%, and surgical procedure 6.4%. The cardinal symptoms were fever, cough, chest pain, dyspnea, sputum, weight loss, anorexia, and night sweat in orders. Culture of empyema fluid were positive in 50% of patients. The isolated organisms were Gram-negative bacilli 33.3%, staphylococcus aureus 25%, and streptococcus 25%. The patients received antibiotics in conjunction with various invasive procedures : chest tube drainage 77.1%, decortication 6.3%, and repeated thoracentesis 10.3%. There were 4 deaths, 1 child and 3 adults, with a overall mortality of 8.3%.

• Nutrition Research and Practice
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• v.5 no.5
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• pp.435-442
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• 2011

At present, lifestyle-related diseases are one of the most critical health issues worldwide. It has been reported that lipopolysaccharide derived from a Gram-negative bacteria (IP-PA1) symbiotic with wheat exhibited several advantageous biological effects, such as the reduction of plasma glucose levels in NOD mice and low-density lipoprotein (LDL) levels in WHHL rabbits. In this study, the beneficial effects on plasma glucose and lipids of a tea (SI tea) consisting of IP-PA1 and Salacia (which contains an inhibitor of ${\alpha}$-glucosidase) were investigated in the KK-Ay/TaJcl type 2 diabetic model mice and in human subjects with premetabolic syndrome in a double-blind, randomized study. S1 tea significantly decreased plasma glucose levels in KK-Ay/TaJcl mice. A clinical trial of SI tea was performed with 41 subjects between the ages of 40 and 69, who belonged either to a high plasma glucose group (HG: FPG 100-125 mg/dl) or to a hyperlipidemia group (HL: TG ${\geq}$ 150 mg/dl, or LDL ${\geq}$ 120 mg/dl, or HDL <40 mg/dl). These subjects ingested either Salacia without IP-PA1 (the control) or SI tea. Blood samples were collected at 0, 30, and 60 days after initiating SI tea treatment, and were measured for FPG, HbA1c, TG, LDL, and HDL. These results showed that SI tea reduced FPG and HbA1c more rapidly than the control in the HL group, and also significantly improved LDL and HDL levels in the HG group. Thus, SI tea may be helpful in preventing lifestyle-related diseases.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.2707-2712
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• 2015

Background: The human homologue of the mouse double minute 2 (MDM2) gene is a negative regulator of Tp53. MDM2-309T>G a functional promoter polymorphism was found to be associated with overexpression thereby attenuation of Tp53 stress response and increased cancer susceptibility. We have planned to evaluate the possible role of MDM2-309T>G polymorphism with risk and response to chemotherapy in AML. Materials and Methods: A total of 223 de novo AML cases and 304 age and sex matched healthy controls were genotyped for the MDM2-309T>G polymorphism through the tetra-primer amplification refractory mutation system (ARMS)-PCR method. In order to assess the functional relationship of -309T>G SNP with MDM2 expression level, we quantified MDM2 mRNA in 30 primary AML blood samples through quantitative RT-PCR. Both the (-309T>G) genotypes and the MDM2 expression were correlated with disease free survival (DFS) rates among patients who have achieved complete remission (CR) after first induction chemotherapy. Results: MDM2-309T>G polymorphism was significantly associated with AML development (p<0.0001). The presence of either GG genotype or G allele at MDM2-309 confered 1.79 (95% CI: 1.12-2.86; p<0.001) and 1.46 fold (95%CI: 1.14-1.86; p= 0.003) increased AML risk. Survival analysis revealed that CR+ve cases with GG genotype had significantly increased DFS rates (16months, p=0.05) compared to CR+ve TT (11 months) and TG (9 months) genotype groups. Further, MDM2 expression was also found to be significantly elevated in GG genotype patients (p=0.0039) and among CR+ve cases (p=0.0036). Conclusions: The MDM2-309T>G polymorphism might be involved in AML development and also serve as a good prognostic indicator.

• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.237-246
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• 2008

The cross-sections of continuous multi-span beams sometimes suddenly increase, or become stepped, at the interior supports of continuous beams to resist high negative moments. The three-dimensional finite-element program ABAQUS (2006) was used to analytically investigate the inelastic lateral-torsional buckling behavior of stepped beams subjected to pure bending moment and resulted in the development of design equations. The flanges of the smaller cross-section were fixed at 30.48 by 2.54 cm, whereas the width and/or thickness of the flanges of the larger cross-section varied. The web thickness and height of beam was kept at 1.65 cm and 88.9 cm, respectively. The ratios of the flange thickness, flange width, and stepped length of beams are considered analytical parameters. Two groups of 27 cases and 35 cases, respectively, were analyzed for double and single stepped beams. The combined effects of residual stresses and geometrical imperfection on inelastic lateral-torsional buckling of beams are considered. First, the distributions of residual stress of the cross-section is same as shown in Pi, etc (1995), and the initial geometric imperfection of the beam is set by central displacement equal to 0.1% of the unbraced length of beam. The new proposed equations definitely improve current design methods for the inelastic LTB problem and increase efficiency in building and bridge design. The proposed solutions can be easily used to develop new design equation for inelastic LTB resistance of stepped beams subjected to general loading condition such as a concentrated load, a series of concentrated loads or uniformly distributed load.

• Advances in pediatric surgery
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• v.1 no.1
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• pp.18-26
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• 1995

For the prevention of later contralateral hernia as well as unnecessary contralateral exploration in pediatric patients with unilateral inguinal hernias, a reasonable indication of contralateral exploration is required. To examine the contralateral positivity, a prospective selective contralateral exploration has been performed by the author from Sept. 1985 to Dec. 1993, at Pediatric Surgical Section of the Department of Surgery, Kangnam St. Mary's Hospital, Catholic University Medical College. Among the total 1200 cases of pediatric inguinal hernias, 580 cases of contralateral side were explored at hernia operations, by the indications as; male with infant onset, 2)female of all age, 3)prematurity, 4)profuse ascites due to cirrhosis, nephrotic syndrome, and ventriculoperitoneal shunt, and 5)remarkable silk sign. Overall positive rate was 71.4%, and positive rates of each indication were 80.7%, 70.4%, 73.1%, 66.7%, and 72.0%, respectively. Right side hernia showed 67.0%, left s ide 75.7%, and positive familial history 71.8% of contralateral positivities. In male, getting older revealed lower positive rates and the rate suddenly dropped after 12 years of age. Birth order, mother's age at delivery, postmaturity did not show any significant differences between the rates. Recurrence was seen in 3(0.5%) ipsilateral and 2(0.3%) contralateral, both of which were negative esplorations on previons operations. Overall complication rate was 3.8%, including 1 infection, 14 fluid or blood accumulation, 5 edemas, 3 temporary testicular edemas, 2 persisting fevers, 2 enures is and one delayed recovery from anesthesia. Among 38 cases with contralateral hernias developed after unilateral surgery by authors(6 cases) or surgeons in other institutions, 14 were males with infant onset, 4 were prematurities and 9 were females. Therefore, 27(71.7%) cases were originally under the contralateral exploration indications. The primary site of the hermia was right in 25 and left in 13. With above results, the following indications for contralateral exploration could be suggested ; 1)under one year of age, both sex, 2)prematurity, 3) remarkable silk sign, 4)in the double checked suspicions among males with infant onset, all age females, ascites, left hernia and familial history. After 12 years of age, exploration is not required. Considering complications, contralateral explorations could be considered only in the following situations; 1)expert, experienced pediatric surgeon, 2)experienced pediatric anesthesiologist, 3)operations could be done smoothly in an hour, 4)good general condition of the patient.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.3
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• pp.173-183
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• 2000

This study measured the zeta potential of both latex colloidal particles with carboxylate surface groups and glass beads (collectors) with silanol surface group employing various solution with different chemical characteristics. The results have been compared with the surface chemistry theory. The zeta potential of the particle and collector increased with increasing pH up to 5.0 regardless of the solution chemistry. For a monovalent electrolyte solution(sodium chloride solution) the zeta potential steadily increased until the pH reached 9.5. In contrast, little change in zeta potential was made between 5.0 and 9.5 for a divalent electrolyte solution (sodium chloride solution) the zeta potential steadily increased until the pH reached 9.5. In contrast, little change in zeta potential was made between 5.0 and 9.5 for a divalent electrolyte solution (calcium chloride solution). In other words, the more the pH decreases, the larger the effect of neutral salts, such as NaCl and CaCl$_2$, have on the ζ-potential values. In this study, the PZPC(point of zero proton condition) of the particle and collector occurred below a pH of 3.1, H(sup)+ and OH(sup)- acted as a PDI (potential determining ion), and Na(sup)+ acted as an IDI(indifferent ion). The magnitude of the negative ζ-potential values of the particle and collector monotonically increased as the concentrations of Na(sup)+ or Ca(sup)2+([Na(sup)+] or [Ca(sup)2+]) decreased (the values of pNa or pCa increased). In the case of latex particles, the ζ-potential should aproach zero (isoelectric point; IEP) asymptotically as the pNa approaches zero, while in the case of calcium chloride electrolyte, ζ-potential reversal may be expected to occur around 3.16$\times$10(sup)-2MCaCl$_2$(pCa=1.5). pH, valance and ionic strength can be used in various ways to improve the water treatment efficiency by modifying the charge characteristics of the particle and collector. Predictive capability is far less certain when EDL(electrical double layer) repulsive forces exist between the particle and collector.