Korea Development Institute

We provide a systematic review of epidemiological surveys of autistic disorder and pervasive developmental disorders (PDDs) worldwide. A secondary aim was to consider the possible impact of geographic, cultural/ethnic, and socioeconomic factors on prevalence estimates and on clinical presentation of PDD. Based on the evidence reviewed, the median of prevalence estimates of autism spectrum disorders was 62/10 000. While existing estimates are variable, the evidence reviewed does not support differences in PDD prevalence by geographic region nor of a strong impact of ethnic/cultural or socioeconomic factors. However, power to detect such effects is seriously limited in existing data sets, particularly in low-income countries. While it is clear that prevalence estimates have increased over time and these vary in different neighboring and distant regions, these findings most likely represent broadening of the diagnostic concets, diagnostic switching from other developmental disabilities to PDD, service availability, and awareness of autistic spectrum disorders in both the lay and professional public. The lack of evidence from the majority of the world's population suggests a critical need for further research and capacity building in low- and middle-income countries.

Methylation of histone H3 at lysine 9 (H3-K9) mediates heterochromatin formation by forming a binding site for HP1 and also participates in silencing gene expression at euchromatic sites. ESET, G9a, SUV39-h1, SUV39-h2, and Eu-HMTase are histone methyltransferases that catalyze H3-K9 methylation in mammalian cells. Previous studies demonstrate that the SUV39-h proteins are preferentially targeted to the pericentric heterochromatin, and mice lacking both Suv39-h genes show cytogenetic abnormalities and an increased incidence of lymphoma. G9a methylates H3-K9 in euchromatin, and G9a null embryos die at 8.5 days postcoitum (dpc). G9a null embryo stem (ES) cells show altered DNA methylation in the Prader-Willi imprinted region and ectopic expression of the Mage genes. So far, an Eu-HMTase mouse knockout has not been reported. ESET catalyzes methylation of H3-K9 and localizes mainly in euchromatin. To investigate the in vivo function of Eset, we have generated an allele that lacks the entire pre- and post-SET domains and that expresses lacZ under the endogenous regulation of the Eset gene. We found that zygotic Eset expression begins at the blastocyst stage and is ubiquitous during postimplantation mouse development, while the maternal Eset transcripts are present in oocytes and persist throughout preimplantation development. The homozygous mutations of Eset resulted in peri-implantation lethality between 3.5 and 5.5 dpc. Blastocysts null for Eset were recovered but in less than Mendelian ratios. Upon culturing, 18 of 24 Eset(-/-) blastocysts showed defective growth of the inner cell mass and, in contrast to the approximately 65% recovery of wild-type and Eset(+/-) ES cells, no Eset(-/-) ES cell lines were obtained. Global H3-K9 trimethylation and DNA methylation at IAP repeats in Eset(-/-) blastocyst outgrowths were not dramatically altered. Together, these results suggest that Eset is required for peri-implantation development and the survival of ES cells.

CONTEXT: The causal relation between school bullying and psychopathologic behavior has been the focus of substantial debate. Previous studies have failed to garner causal evidence in either direction, largely because of methodologic constraints such as cross-sectional study designs, shared method variance, and analytic shortfalls. OBJECTIVE: To determine the direction of the causal relation between psychopathologic behavior and school bullying. DESIGN: Prospective cohort study. SETTING: Two Korean middle schools. PARTICIPANTS: A total of 1655 seventh- and eighth-grade students were studied between 2000 and 2001. MAIN OUTCOME MEASURES: School bullying was assessed by peer nomination, and 7 subscales of the Korean Youth Self Report were used to identify symptoms of psychopathologic behaviors. School bullying was categorized into 4 groups: victims, perpetrators, victim-perpetrators, and neither. A T-score on the Korean Youth Self Report greater than 65 was regarded as a clinically significant indicator. RESULTS: Social problems increased the risk of becoming a victim or a victim-perpetrator (odds ratio [OR], 2.3 and 2.7, respectively), and these associations disappeared when baseline bullying status was adjusted. Ten months later, individuals who were victims at baseline showed increased risk of social problems (OR, 3.9), those who were perpetrators had increased aggression (OR, 1.8), and victim-perpetrators had increased aggression and externalizing problems (OR, 4.9 and 4.6, respectively). Analyses that examined exposure history provided additional evidence for the causal effect of bullying experience on the later development of psychopathologic behaviors because most forms of psychopathologic behavior that led to new-onset bullying at follow-up were also present at follow-up, making it impossible to distinguish the temporal sequence of these variables and their causal relationship. However, most forms of new-onset psychopathologic behaviors at follow-up were associated with antecedent bullying experience. CONCLUSIONS: Our study results support the conclusion that psychopathologic behavior, including social problems, aggression, and externalizing behavioral problems, is a consequence rather than a cause of bullying experiences. This causal relation is supported by the strength and specificity of the association and the temporal antecedence of bullying. Because school bullying is a known correlate of youth violence, such a finding adds greater urgency to the search for programs to prevent or diminish bullying among schoolchildren.

Using Add Health data, the authors provide evidence that some adolescents gave inaccurate and/or invalid responses on a self-administered questionnaire. Further analyses show that these adolescents were much more likely to report extreme levels on psychosocial and behavioral outcome variables. A distinction was made between inaccurate responders (e.g., inaccurate/false responses due to carelessness or confusion) and jokesters (e.g., intentional false responses). The findings show that the jokesters showed considerably more pronounced distorting effects on some psychosocial and behavioral outcome variables than the inaccurate responders did. The authors suggest that although this jokester effect may not seriously bias the results in studies that focus on large groups, for research focusing on some special subgroups (e.g., adoption groups, immigrant groups, disability groups), this effect could pose a serious challenge for the validity of research findings.

I. Introduction, 323. — II. Direct linkages, 324, — III. Indirect linkages: Y & N and Rasmussen, 325. — IV. The “output inverse” and forward linkages, 327. — V. Average and total linkage, 329. — VI. Trade effects, 329. — VII. The level of aggregation, 331. — VIII. Conclusion, 332. — Appendix: simple numerical example, 333.

The economic crisis associated with the emergence of the novel corona virus is unlike standard recessions. Demand for workers in high contact and inflexible service occupations has declined while parental supply of labor has been reduced by lack of access to reliable child care and in-person schooling options. This has led to a substantial and persistent drop in employment and labor force participation for women, who are typically less affected by recessions than men. We examine real-time data on employment, unemployment, labor force participation and gross job flows to document the impact of the pandemic by occupation, gender and family status. We also discuss the potential long-term implications of this crisis, including the role of automation in depressing the recovery of employment for the worst hit service occupations.

Abstract This paper investigates whether the size and book-to-market factors of Fama and French (1993) proxy for the risks associated with business cycle fluctuations. We find that changes in default spread (Δ def ) and changes in term spread (Δ term ) capture the systematic differences in average returns along the size and book-to-market dimensions in the way that the Fama-French factors do: small stock portfolios have higher loadings on Δ def than large stock portfolios, while high book-to-market portfolios have higher loadings on Δ term than low book-to-market portfolios. Furthermore, in the presence of Δ def and Δ term , the Fama-French factors are superfluous in explaining the size and book-to-market effects. The results suggest that the size and value premiums are compensation for higher exposure to the risks related to changing credit market conditions and interest rates proxied by Δ def and Δ term .

Over the last twenty‐five years, the economy of the Republic of Korea achieved a remarkable growth rate of 7 percent per year in real per capita income, causing it to be labeled, justifiably, as a “miracle economy.” This exceptional economic growth has beenpp accompanied by an even more exceptional fall m labor income inequality. Using a newly‐developed methodology, we use data from Korea's Occupational Wage Surveys to quantify the importance of various factors that have contributed to the fall in labor income inequality in Korea. We find the most important factors explaining the level of income inequality are job tenure, gender, years of education, and occupation, while those that are most important in explaining the change in income inequality are years of education, industry, occupation, and potential experience.

This study examines the independent impact of bullying on suicide risk. Bullying was assessed by peer nomination in a prospective study of 1,655 7th and 8th grade Korean students, and suicide by youth self-report. Odds Ratios (ORs) of bullying for suicidal risks were computed, controlling for other suicide risk factors. Victim-Perpetrators and female Victims at baseline showed increased risk for persistent suicidality (OR: 2.4-9.8). Male Incident Victims exhibited increased risk for suicidal behaviors and ideations (OR = 4.4, 3.6). Female Persistent Perpetrators exhibited increased risks for suicidal behaviors; male Incident Perpetrators had increased risk for suicidal ideations (OR = 2.7, 2.3). Baseline-only male Victim-Perpetrators showed increased risk for suicidal ideations. (OR = 6.4). Bullying independently increased suicide risks.

A computable general equilibrium (CGE) model is used to estimate the macroeconomic and distributional effects of the privatization and regulation of utilities in Argentina, begun in 1989. Based on data available after the privatization that indicate different kinds of efficiency gains in electricity, gas, water, and telecommunications, both the privatization and effective regulation are estimated to yield significant macroeconomic benefits. Gains from the privatization accrue mainly to high-income classes, while gains from the effective regulation of newly privatized utilities accrue mainly to low-income classes. CGE estimates of overall employment effects suggest that privatization was not a major contributor to the dramatic rise in unemployment in Argentina between 1993 and 1995. This rise was more likely due to the “Tequila Effect” of an interest rate shock.

In an oligopolistic product market, shareholders strategically use information on rival firms'performances when designing management-incentive contracts. When shareholders use industry performance information through relative performances evaluation (RPE), they evaluate their manager's effort more easily, but hinder collusive behavior in the product market. However, when compensation is positively linked to the industry performance through strategic group performance evaluation (SGPE), the credibility of a manager's commitment to product market collusion increases, and the sustainability of a collusive outcome increases. I test how industry performance affects management-incentive compensation using the data from 796 Japanese firms during the period 1968 to 1992. The results show that management compensation is positively linked to industry profit, suggesting the use of SGPE in management-incentive compensation. Cross-sectional analysis shows that the positive effect of industry profit on management compensation is higher in competitive industries than in concentrated industries. The positive effect is greater in slow-growing industries than in fast-growing industries. Empirical tests incorporating the risk component method show the same results. These results are consistent with the argument that, in a growing market or in a concentrated market, the value of SGPE diminishes as the value of commitment to collusion diminishes.

The microstructures and mechanical properties of cobalt-chromium (Co-Cr) alloys produced by three CAD/CAM-based processing techniques were investigated in comparison with those produced by the traditional casting technique. Four groups of disc- (microstructures) or dumbbell- (mechanical properties) specimens made of Co-Cr alloys were prepared using casting (CS), milling (ML), selective laser melting (SLM), and milling/post-sintering (ML/PS). For each technique, the corresponding commercial alloy material was used. The microstructures of the specimens were evaluated via X-ray diffractometry, optical and scanning electron microscopy with energy-dispersive X-ray spectroscopy, and electron backscattered diffraction pattern analysis. The mechanical properties were evaluated using a tensile test according to ISO 22674 (n = 6). The microstructure of the alloys was strongly influenced by the manufacturing processes. Overall, the SLM group showed superior mechanical properties, the ML/PS group being nearly comparable. The mechanical properties of the ML group were inferior to those of the CS group. The microstructures and mechanical properties of Co-Cr alloys were greatly dependent on the manufacturing technique as well as the chemical composition. The SLM and ML/PS techniques may be considered promising alternatives to the Co-Cr alloy casting process.

The Ge/sub 2/Sb/sub 2/Te/sub 5/ (GST) thin film is well known to play a critical role in PRAM (Phase Change Random Access Memory). Through device simulation, we found that high-resistive GST is indispensable to minimize the writing current of PRAM. For the first time, we tried to increase the GST resistivity by doping nitrogen. Doping nitrogen to GST successfully reduced writing current. Also, the cell endurance has been enhanced with grain growth suppression effect of dopant nitrogen.

This DPR Debate is based on the contribution by Justin Lin, Chief Economist at the World Bank, and his colleague Célestin Monga, on ‘Growth Identification and Facilitation: The Role of the State in the Dynamics of Structural Change’. The article under consideration is important and timely as it articulates a number of new policy implications from Justin Lin's earlier work on New Structural Economics, which was discussed in a previous DPR debate (Lin and Chang, 2009). This symposium contains the article and comments on it from five distinguished specialists, and closes with a rejoinder by Lin and Monga. This introduction discusses the article, the comments and the rejoinder. The historical record indicates that, in all successful economies, the state has always played an important role in facilitating structural change and helping the private sector sustain it across time. This article puts forward a new approach to help policy‐makers in developing countries identify those industries that may hold latent comparative advantage, and recommends ways of removing binding constraints to facilitate private firms' entry into those industries. Two types of government interventions are distinguished: first, policies that facilitate structural change by overcoming information, co‐ordination and externality issues, which are intrinsic to industrial upgrading and diversification; and second, policies aimed at protecting certain selected firms and industries that defy the comparative advantage determined by the existing endowment structure.

In 1994, Bangladesh introduced the Female Secondary School Stipend Program that made secondary education free for rural girls. This paper examines the long-term effects of the stipend program on education, marriage, fertility, and labor market outcomes of women. We find that the stipend increased years of education for eligible girls by 14%–25%. These girls were more likely to get married later and have fewer children. They also had more autonomy in making decisions about household purchases, health care, and visiting relatives. They were more likely to work in the formal sector than the agricultural or informal sector. Eligible women were likely to marry more educated husbands who had better occupations and were closer in age to their own. Their children’s health outcomes also improved. These results imply that school-based stipend programs can increase female empowerment through positive effects on schooling and marriage market outcomes over the long term.

This paper presents a small-sample study of the threeequation-three variable New-Keynesian macro model. While the point estimates imply that the Fed has been stabilizing inflation fluctuations since 1980, our econometric analysis suggests considerable uncertainty regarding the stance of the Fed against inflation. We show that, if we add first order autocorrelation to the error terms of the New-Keynesian model, this is only marginally rejected.

In order to improve the effectiveness of transit-oriented development (TOD), the integration of public transportation and bikes has been regarded as a good alternative because the catchment area of a station, that is, the spatial extent of TOD, can be increased. This paper suggests the concept of bicycle-based TOD (B-TOD) and estimates the spatial extent, considering the catchment area. For this, a trip survey was conducted among bicycle users who used bicycle and public transportation in Seoul metropolitan and Daejeon metropolitan areas in Korea. Regression and cumulative distribution models were used to estimate the spatial extent of B-TOD. The results show that the estimated access distances were 1.96 km and 2.13 km for origin (home)-to-station and station-to-work trips, respectively, and they can play a yardstick role in the TOD planning practices in Korea. In such cases, the catchment areas of B-TOD cover 73.7% and 93.6% of the whole area of Seoul, whereas conventional walking-only TOD can cover only 29.9% of the same. This implies that B-TOD can help to solve one of the key inherent weaknesses of the conventional TOD. Some limitations and recommendations for future research are also discussed.

Abstract South Korea's official development assistance (ODA) has been increasing rapidly and will continue to do so. Korea is one of the few countries which have successfully transitioned from a recipient to a donor. It became a member of DAC (development assistance committee), OECD in November 2009. Korea's ODA policy, along with its growth in quantity, is at a crossroads for the enhancement of its quality. Discussions and debates are going on regarding the reforms in Korea's ODA activities, and this paper examines key issues raised. It first reviews the past and present of Korea's ODA, and identifies major characteristics including a low ODA/GNI ratio, a high percentage of concessional loans compared to grants, a high portion of tied aid, regional bias and a relatively large number of recipients. The paper argues that those characteristics arise from a lack of consensus on some fundamental issues like the objective of ODA, positioning of Korea's ODA as an emerging donor and the nature of aid to North Korea. We also argue that a shift of ODA policy is required to promote reform, based on a thorough reflection on the role of ODA in the alleviation of poverty and promoting sustainable development in developing countries, rather than serving as an economic tool. Copyright © 2010 John Wiley & Sons, Ltd.

Mongolia's mass privatization program was implanted in a country that lacked the very basic institutions of capitalism. This paper examines the effects of competition and ownership on the efficiency of the newly privatized enterprises, using a representative sample of enterprises and controlling for possible selection biases. Competition has quantitatively large effects; perfectly competitive firms having nearly double the efficiency of monopolies. Enterprises with residual state ownership appear to be more efficient than other enterprises, reflecting an environment where the government was pressured to focus on efficiency and institutions gave little voice to outsider owners.

Tooth morphogenesis is a well-known developmental system related to epithelial-mesenchymal interactions. In mice, the dental epithelium has the potential to induce tooth formation prior to the bud stage, whereas this potential shifts to the dental mesenchyme from the dental epithelium. The reaggregation of mesenchymal tissue leads to previous memories of individual cells being reset, which is useful for studying the predetermination of mesenchyme. Here, the mesenchyme was triturated into single cells after separation of the epithelium and the mesenchyme. These single cells were repelleted and combined with the epithelium. The reaggregated tooth was transplanted into a mice kidney capsule. In order to investigate the essential functions of both the dental epithelium and the dental mesenchyme regarding their mutual interaction, a reaggregation system was introduced using the late bud stage of the mouse first molar. Amelogenin expression was examined to confirm the cytodifferentiation in the reaggregated tooth. The results showed that a new tooth formed after reaggregating the dental mesenchyme. This tooth contained enamel, dentin, dentinal tubules and dental pulp. The inner enamel epithelium of the reaggregated tooth differentiated into ameloblasts. Immunohistochemistry for amelogenin was observed both in the ameloblasts and the enamel. However, the structure of the enamel was different from that of the normal tooth, with the thickness of the predentin becoming wider. These findings suggest that reaggregated dental mesenchyme cells can produce a tooth. The fate of dental epithelium was not affected by reaggregated dental mesenchyme, although the dental mesenchyme appears to lose the information from the dental epithelium.