• Title/Summary/Keyword: Critical period

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Examining the Moderating Effect of Involvement in the Internet Purchase Decision Process (인터넷 구매결정과정에서의 관여도의 조절효과에 관한 연구)

  • Kwahk, Kee-Young;Ji, So-Young
    • Asia pacific journal of information systems
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    • v.18 no.2
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    • pp.15-40
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    • 2008
  • With the explosive growth of the Internet, Internet shopping malls have become recognized as one of the major purchasing channels for consumers, as well as one of the competitive distribution channels for companies that allow them to contact with customers without intermediaries. It has motivated information systems(IS) researchers to examine the factors influencing consumer behavior and the purchase decision process in the context of Internet shopping malls. Despite the extensive research that has been conducted on the purchase decision process of consumers in online shopping malls, the results have demonstrated a need for further understanding of consumer behavior due to the unique features of virtual space and the characteristics of online consumers. Previous studies from marketing and consumer behavior domains have suggested that the concept of involvement plays an important role in explaining consumers' purchase behavior. Despite the critical role of involvement and the explosive growth of e-commerce, little research has examined the role of involvement in the Internet shopping mall context. With this motivation, this study has two research objectives. First, it introduces and tests an theoretical model capable of better explaining consumers' intention to purchase in the Internet shopping mall context. The proposed model extends and integrates existing models on purchase intention by incorporating purchase experience, innovativeness, and perceived self-control as the consumer factors, along with perceived risk, information provision, and perceived price as the Internet shopping mall factors. Second, this study examines how involvement differences may affect consumers' intention to purchase. For this purpose, two factors from involvement theory, involvement type and involvement level, are introduced into the research model as moderating variables. In order to test the proposed model, the overall approach employed was a field study using the structural equation model. We developed our data collection instrument by adopting existing validated questions wherever possible. All question items were measured with a seven-point, Likert-type scale, with anchors ranging from 'strongly disagree' to 'strongly agree.' Two IS researchers reviewed the instrument and checked its face validity. We collected empirical data for this study over a period of two weeks from subjects who had purchase experiences through Internet shopping malls. A total of 473 complete and valid responses were obtained. We carried out data analysis using a two-step methodology with AMOS 4.0. The first step in the data analysis was to establish the convergent and discriminant validity of the constructs. In the second step, we examined the structural model based on the cleansed measurement model. The empirical results partly support the proposed model and identify the moderating effect of involvement differences. Theoretical and practical implications of the study are discussed, along with its limitations.

Numerical Simulations of Nonlinear Behaviors of Pulsating Instabilities in Counterflow Diffusion Flames (대향류 확산화염에서 맥동 불안정성의 비선형 거동에 대한 수치해석)

  • Lee, Su-Ryong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.9
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    • pp.859-866
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    • 2010
  • Nonlinear dynamics of pulsating instability-diffusional-thermal instability with Lewis numbers sufficiently higher than unity-in counterflow diffusion flames, is numerically investigated by imposing a Damkohler number perturbation. The flame evolution exhibits three types of nonlinear behaviors, namely, decaying pulsating behavior, diverging behavior (which leads to extinction), and stable limit-cycle behavior. The stable limit-cycle behavior is observed in counterflow diffusion flames, but not in diffusion flames with a stagnant mixing layer. The critical value of the perturbed Damkohler number, which indicates the region where the three different flame behaviors can be observed, is obtained. A stable simple limit cycle, in which two supercritical Hopf bifurcations exist, is found in a narrow range of Damkohler numbers. As the flame temperature is increased, the stable simple limit cycle disappears and an unstable limit cycle corresponding to subcritical Hopf bifurcation appears. The period-doubling bifurcation is found to occur in a certain range of Damkohler numbers and temperatures, which leads to extend the lower boundary of supercritical Hopf bifurcation.

Viral Hepatitis and Liver Cancer in Korea: an Epidemiological Perspective

  • Yeo, Yohwan;Gwack, Jin;Kang, Seokin;Koo, Boyeon;Jung, Sun Jae;Dhamala, Prakash;Ko, Kwang-Pil;Lim, Young-Khi;Yoo, Keun-Young
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.11
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    • pp.6227-6231
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    • 2013
  • In the past, hepatitis B virus (HBV) infection was endemic in the general Korean population. The association of HBV infection with the occurrence of liver cancer has been well demonstrated in several epidemiologic studies. While the mortality rates of liver cancer in Korea have decreased steadily over the last decade, the presence of hepatitis B surface antigen (HBsAg) in mothers remains high at 3-4%, and 25.5% of these HBsAg positive mothers are positive for hepatitis B e antigen (HBeAg). HBV infection caused almost a quarter of hepatocellular carcinoma (HCC) cases and one-third of deaths from HCC. These aspects of HBV infection prompted the Korean government to create a vaccination program against HBV in the early 1980s. In 1995, the Communicable Disease Prevention Act (CDPA) was reformed, and the government increased the number of HBV vaccines in the National Immunization Program (NIP), driving the vaccination rate up to 95%. In 2000, the National Health Insurance Act (NHIA) was enacted, which provided increased resources for the prevention of perinatal HBV infection. Then in 2002, the Korean government, in conjunction with the Korean Medical Association (KMA), launched an HBV perinatal transmission prevention program. The prevalence of HBsAg in children had been high (4-5%) in the early 1980s, but had dropped to below 1% in 1995, and finally reached 0.2% in 2006 after the NIP had been implemented. After the success of the NIP, Korea finally obtained its first certification of achievement from the Western Pacific Regional Office of the World Health Organization (WPRO-WHO) for reaching its goal for HBV control. An age-period-cohort analysis showed a significant reduction in the liver cancer mortality rate in children and adolescents after the NIP had been implemented. In addition to its vaccination efforts, Korea launched the National Cancer Screening Program (NCSP) for 5 leading sites of cancer, including the liver, in 1999. As a consequence of this program, the 5-year liver cancer survival rate increased from 13.2% (1996-2000) to 23.3% (2003-2008). The development of both the primary and secondary prevention for liver cancer including HBV immunization and cancer screening has been of critical importance.

Micelles in Physical Chemistry Laboratory. Surfactant Catalyzed Oxidation of Glycine by Acidic Permanganate

  • Pare, Brijesh;Kaur, Parwinder;Bhagwat, V.W.;Fogliani, Charles
    • Journal of the Korean Chemical Society
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    • v.48 no.2
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    • pp.195-202
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    • 2004
  • Micellar catalysis is an essential part of theoretical and experimental curricular. The sodium dodecylsulfate (SDS) catalyzed reaction between glycine and potassium permanganate in acidic medium is an ideal kinetic experiment for the secondary and undergraduate physical chemistry laboratory, to show the effect of micellar catalysis on rate of the reaction. The reaction is conducted both with and without SDS to observe the rate enhancement in the presence of surfactant. To show surfactant catalysis a plot between k and [SDS] is plotted. As surfactant catalysis is observed even before the critical micelle concentration of SDS, this pre-micellar catalysis can be understood in the light of positive co-operativity. The value of positive cooperative index (n) has been found to be 2.37. Further, dependence of the reaction rate on substrate and oxidant concentrations is also discussed. The reaction follows pseudo-first-order kinetics. The overall reaction is second order, with first-order dependence on both glycine and permanganate concentrations. The theory of surfactant catalysis is also discussed. With the conditions specified in the experiment, total reaction times are in 3~4 hours lab session, thus allowing several data sets to be acquired in a single laboratory period. Preparation of solutions and procedure is also given in detail.

Shipowner's Lost Profit and Its Claim resulted from Delay in Redelivery under Time Charter (정기용선계약에서 반선지연에 의한 선주의 상실수익과 손해배상청구)

  • Han, Nak-Hyun;Jung, Jun-Sik
    • Journal of Korea Port Economic Association
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    • v.23 no.3
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    • pp.29-51
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    • 2007
  • The purpose of this study aims to explore shipowner's lost profit and its claim resulted from delay in redelivery under time charter with the Achilleas case. In this case, the charterers submitted that there was an established prima facie measure of damages in cases of late delivery, namely the difference between the market rate and the charter-party rate for the period from the time when the vessel should have been delivered until the time of her actual redelivery. An award for lost profit in respect of a subsequent charter could only be made under the second limb because the charterers had not been told, at or before the making of the addendum, that the owners were going to enter into a subsequent fixture and that it was critical that redelivery take place on time. However, the owners said their losses that was a not unlikely consequence of the charterers' breach. There was no special rule that the first limb could only lead to damages calculated by taking the difference between the market and the charter-party rate for the overrun. To award damages in the Achilleas case on the basis of the difference between the market and the charter rate for the overrun would compensate the owners for only a fraction of the true loss caused by the breach.

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Ecological Studies on Pal'tang River-Reservoir System in Korea. 4. Dynamics on Inorganic nutrients, POM and Phytoplankton Succession in the Lower Stream Kyungan (팔당호의 생태학적 연구 4. 경안천 하류의 영양염 및 입자태 유기물 거동과 식물플랑크톤의 천이)

  • Hong, Sung-Su;Auh, Yun-Yeol;Han, : Myung-Soo
    • Korean Journal of Ecology and Environment
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    • v.35 no.1 s.97
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    • pp.1-9
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    • 2002
  • In order to understand the relationship between succession of phytoplankton community structure and inorganic nutrients and particulate organic matters, a one station in Kyungan stream in Korea during the dry season was chosen. Water samplings were carried out once a week from 18 August to 13 November 1993. The DIN concentration distributed always abundantly, however, phosphate and silicate gradually reduced during the period. Phytoplankton community had a peak chlorophyll a concentration of $90.6\;{\mu}g/l$ in late summer (21 August 1993) and a second peak of $29.7\;{\mu}g/l$ in autumn (2 October 1993). After then late autumn was characterined by relatively low chlorophyll a concentration of $15{\sim}16\;{\mu}g/l$. Seasonal fluctuation of chlorophyll a concentrations were correlated with measured POC and PON concentrations: phytoplankton blooming may be a major factor controlling POC and PON concentrations in this ecosystem. Phosphate plays an most important role as a limiting factor of phytoplankton growth. However, when Si/P ratio low, silicate may be a more critical limiting factor than phosphate. Shifts of P-limitation to Si- limitation the succession of dominant phytoplankton can in duce: diatom to cyanobacteria such as Anabaena, Microcystis and Oscillatoria.

Effect of Some Variation Factors on Dissipation of Tebuconazole in Grape (포도 중 Tebuconazole의 잔류성에 미치는 몇 가지 변동요인의 영향)

  • Han, Seong-Soo;Lo, Seog-Cho;Ma, Sang-Yong
    • Korean Journal of Environmental Agriculture
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    • v.23 no.3
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    • pp.142-147
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    • 2004
  • Dissipation pattern of tebuconazole was evaluated by establishing application methods of the fungicide, paper-bagging of grape during growth and washing of grape after harvest. Application times increased from three to five resulted in high levels of residues in grape. Tebuconazole in grapes was present in different residual patterns with periods after final treatment ranging from 7 to 25 days. Significant differences in the residual patterns were also found when tebuconazole was treated during three different application periods, possibly due to meteorological condition and/or grape growth during each period. At the range from 2.5 g to 7.5 g of grape granules, residues were higher in small-sized grape than in big-sized grape and were mostly distributed on the peel of the grapes. Paper-bagging was a critical factor for reducing the fungicide residue on the peel. flesh of bagged and no-bagged grape had very low level of residues, 0.01 mg/kg and 0.05 mg/kg, respectively. Residues on grape was effectively eliminated with the washing methods suggested, a consecutive sinking-washing system Using of detergent solution during washing showed maximum residue reduction from grape. The washing methods showed effective action on the removal of lower content providing complete elimination, or almost, of the residues.

Use of a Postoperative Hepatic Arterial Embolization in Patients with Postoperative Bleeding due to Severe Hepatic Injuries (외상성 대량 간 손상 환자에서 수술 후 간 동맥 색전술의 유용성)

  • Cha, Soo Hyun;Jung, Yong Sik;Won, Jae Hwan;Kim, Wook Whan;Wang, Hee Jung;Kim, Myung Wook;Lee, Kug Jong
    • Journal of Trauma and Injury
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    • v.19 no.1
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    • pp.59-66
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    • 2006
  • Purpose: Acute liver failure after massive partial hepatectomy is critical condition with high mortality. To prevent postoperative liver failure from being induced by a massive partial hepatectomy, many doctors do a minimal resection on the single lobe of the liver that might cause postoperative bleeding from the remaining ruptured parenchyma. The objective of this study was to assess clinical experience with postoperative hepatic arterial embolization to control bleeding from the remaining ruptured liver during the postoperative period. Methods: This retrospective 4-year study was conducted from May 2002 to April 2006 and included consecutive patients who had sustained massive hepatic injuries and who had undergone a laparotomy, followed by postoperative hepatic arterial angiographic embolization to control bleeding. Data on the injury characteristics, the operative treatment and embolization, and the amount of transfused packed red cells (PRBC) were gathered and analyzed. In addition, data on the overall complications and survival rate were collected and analyzed. Results: Every case showed severe liver injury, higher liver injury scaling grade IV. Only ten cases involved a ruptured bilateral liver lobe. A lobectomy was done in 6 cases, a left lobectomy was done in 3 cases, and a primary suture closure of the liver was done in 2 cases. Suture closure was also done on the remaining ruptured liver parenchyma in cases of lobectomies. The postoperative hepatic arterial embolizations were done by using the super-selection technique. There were some cases of arterio-venous malformations and anomalous vessel branches. The average amount of transfused PRBC during 24 hours after embolization was $2.36{\pm}1.75$, which statistically significantly lower than that before embolization. Among the 11 cases, 9 patients survived, and 2 died. There was no specific complications induced by the embolization. Conclusion: In cases of postoperative bleeding in severe hepatic injury, if there is still a large amount of bleeding, postoperative hepatic arterial embolization might be a good therapeutic option.

A Critical Approach on Family Support, Social Security, and its Direction: Focusing on Old Parents and Children from Divorced Families (가족부양 쟁점에 관한 일고찰: 노인과 이혼가족 아동을 중심으로)

  • Song, Da-Young
    • Korean Journal of Social Welfare
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    • v.57 no.2
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    • pp.143-164
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    • 2005
  • The study is to analyze support-related issues, particularly associated with elderly and children care, which have been a fundamental agenda of family welfare policy. We are expected for societal-level controversy on the relationship of family support and social security in the near future because of rapid increase in ageing and divorce rate. Accordingly, we need to establish social consensus on the extent to which both family support system and social support system are responsible for the life maintenance of the elderly and the children from divorced family. We also clarify the various characteristics(including scope, degree, period of time, and need/manageability) of support provided by family members. Considering the changes of family structure and population composition, the policy of supporting the old and children should go for social responsibility. Findings show that civil law and social welfare law have unclear application on the relationship between family support and social security, and contents in family support. In particular, public assistance law strongly emphasizes the principle of family support while social insurance laws provide only limited and insufficient family maintenance. The suggestions of further study on support-related issues are given in the rapidly changing society and the increasing economic instability.

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An Analysis of Primary Causes for Waiting for Inpatient Admission and Length of stay at Emergency Medical Center(EMC) (응급의료 센터의 체류 및 입원대기 시간 지연 요인 - 일개 의료기관을 중심으로 -)

  • Kil Suk-Yong;Kim Ok-Jun;Park Jin-Sun
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.6 no.3
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    • pp.522-531
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    • 1999
  • This research identifies the ingress to egress primary factors that causes a patient to receive delayed emergency medical care. This material was collected between February 1st to 28th, 1998. Research envolved 4,118 people who visited the college emergency medical center in Kyeongido Province, South Korea. Medical records were examined, using the retrospective method. to determine the length of stay and the main cause for waiting. Results are as follows : 1. The age group with the highest admission rate was 10 and under, approximately 1,394 (33.9%). Followed by an even distribution for ages between 11-50 at 10-15% for their respective ranges. The lowest admission rate was 50 years and above. 2. From the 4,118 records examined, 3,489 received outpatient treatment (84.7%); 601 were admitted for inpatient care (14.6%); 25 arrived dead on arrival (0.6%); and 4 people died at the hospital. 3. Between 7PM to 12AM, 42.9% were admitted to the EMC. The hours from 9PM to 11PM recorded the highest admission rate and 5AM to 8AM was the lowest From 8PM to 12AM, the most beds were occupied. 4. For most patients. the average length of stay was approximately 2.2 hours. By medical department, external medicine was the longest for 2.8 hours. Pediatrics was the shortest for 1.6 hours. The average waiting period for inpatient admission was 2.6 hours. Inpatient admission for pediatrics and external medicine was 3.4 hours and 2.2 hours respectively. 5. Theses are primary factors for delay at EMC: 1) pronged medical consultations to decide between inpatient versus outpatient treatment, and delaying to be inpatient, 2) when you call physicians they are delayed to come 3) Understaffing during peak or critical hours, 4) Excessive consulting with different medical departments, 5) some patients require longer monitoring periods, 6) medical records are delayed in transit between departments, 7) repeated laboratory tests make delay the result, 8) overcrowded emergency x-ray place causes delay taking x-ray and portable x-ray, 9) the distance between EMC and registration and cashier offices is too far. 10) hard to control patient's family members. The best way to reduce EMC waiting and staying time is by cooperation between departments, both medical and administrative. Each department must work beyond their job description or duty and help each other to provide the best medical service and satisfy the patient needs. The most important answer to shortened the EMC point from ingress to egress is to see things from a patient point of view and begin from there to find the solution.

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