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Since the mid-1980s, the volatility of major macro variables has decreased remarkably, known as the Great Moderation. Even though a great deal of literature addresses the sources of the Great Moderation, its association with potential changes in the dynamics of consumption or output has not been investigated rigorously. This paper reports two empirical findings: i) a faster adjustment of output to changes in its long-run random walk component and ii) a faster adjustment of consumption to changes in permanent income (as approximated by the random walk component of real output) since the mid-1980s. Our interpretation is that a faster diffusion of technology shocks induced by improved information technology may be responsible for the former. In the presence of precautionary savings, a change in the consumer behavior induced by lower uncertainty about future income may be responsible for the latter. The change in output dynamics itself may also be responsible for the change in consumer behavior, as implied by Deaton (1991).

Korean Abstract: 최근 빅데이터 활용을 위한 텍스트 마이닝 기법이 개발됨에 따라 경제분석에서도 비정형 텍스트 데이터 활용이 확대되고 있다. 본 연구에서는 텍스트 데이터의 유용성을 살펴보기 위해 인터넷 검색 정보를 반영하는 구글 트렌드 데이터를 고려하고 정보의 적시성과 예측력을 필요로 하는 금융위기 조기경보모형에서 텍스트 데이터의 유용성을 분석하였다. 실증분석 결과, 구글 트렌드 데이터는 비모수적 모형이나 모수적 모형에서 모두 금융위기를 예측하는데 유용한 것으로 나타났다. 본 연구 결과는 다양한 텍스트 데이터를 개발하고 경제분석에 활용하는 모형들을 더욱 확대시킬 것을 시사하고 있다. English Abstract: As recently the text mining methodology for the usefulness of the big data has been developed, its’ application in the economic analysis has been growing. This study considers the Google Trends Data which reflects the internet search information in order to examine the usefulness of the text data and applies the data to the financial early warning system which needs the timely information and imminent forecasting. The estimation results show that the Google Trends Data appears to be useful for the prediction of the financial crisis both in the parametric and non-parametric approach. This study suggests that we try to develop more text mining methods and expand their applications to various economic analysis.

We validated candidate biomarkers using circulating miRNAs by analyzing serum miRNA concentrations from patients with gastric cancer (GC) to predict lymph node (LN) metastasis. In a pilot study, serum levels of miR-21, miR-27a, miR-106b, miR-146a, miR-148a, miR-223, and miR-433 were compared in 10 healthy donors, 16 LN-positive patients with GC, and 15 LN-negative patients with GC. Then, we compared the level of three miRNAs (miR-21, miR-146a, and miR-148a) with the total of 79 GC patients with or without LN metastasis. In the pilot study, miR-21, miR-27a, miR-106b, miR-146a, miR-148a, and miR-223 concentrations from LN-positive patients with GC were significantly different from those of LN-negative patients with GC (P0.001, P = 0.003, P = 0.033, P0.001, P0.001, and P = 0.017, respectively). In the validation study, levels of miR-21, miR-146a, and miR-148a increased as pN stage increased (P 0.001, P = 0.001, and P0.001, respectively). Levels of the miRNAs were significantly different between pN0 and pN0 in the pT1 group (P = 0.013, P = 0.004, and P = 0.035, respectively) and among clinical stages (P = 0.001, P = 0.002, and P0.001, respectively). No differences in miRNA levels were observed by pT stage, Lauren's classification, sex, or age. Serum concentrations of miR-21, miR-146a, and miR-148a were closely associated with GC pN stage. These serum miRNA levels could be biomarker candidates to predict the presence of LN metastasis.

Background Given the increasing use of endoscopic resection as a therapeutic modality for cases of early gastric cancer (EGC), it is very important to define strict criteria for the use of endoscopic mucosal resection and endoscopic submucosal dissection. To date, the criteria are almost entirely based on Japanese literature evaluating the risk of lymph node (LN) metastasis in patients with EGC. Objective To analyze our own experience with the factors affecting LN metastasis and to reappraise the extended criteria for endoscopic submucosal dissection. Design Retrospective, single-center study. Setting University teaching hospital. Patients This study involved 478 patients who underwent gastrectomy with LN dissection (n = 270, mucosal [m] EGC; n=208, submucosal [sm] EGC). Intervention Gastrectomy with LN dissection. Main Outcome Measurements LN metastasis. Results Overall, 12.6% (60/478) of patients with EGCs presented with LN metastasis (mEGC, 3.0% [8/270], smEGC, 25.0% [52/208]). Increased size, macroscopic type (elevated), depth of invasion, and lymphovascular invasion were associated with LN metastasis. In 270 cases of mEGC, there was no relationship between clinicopathologic features and LN metastasis. In the smEGC group, size, depth of invasion, and lymphovascular emboli were associated with an increased risk of LN metastasis. Significantly, LN metastasis was noted in EGCs falling within established extended endoscopic submucosal dissection criteria, that is, intestinal-type mucosal cancer of any size without ulcer and no lymphovascular emboli (2/146 [1.4%]) or ≤3 cm with no lymphovascular emboli and irrespective of the presence of ulceration (2/126 [1.6%]) or intestinal-type submucosal cancer (sm1, Limitations Retrospective review of a single-center study. Conclusion We recommend that more centers survey their experiences of LN metastasis in cases of EGC to refine the criteria for endoscopic submucosal dissection as a therapeutic modality of intestinal-type EGC.

Korean Abstract: 본 연구는 일국의 금융시장 충격이 타국의 금융시장에 어떻게 영향을 끼치는 지를 분석하기위하여 先行연구들이 취했던 자산가격의 국내전이효과, 또는 주식시장간 전이효과 등과 같은 개별 금융변수들이 국내금융시장에 미치는 효과만을 평가하는 방법에서 벗어나 일국 금융시장의 전반적인 여건의 변화가 타국의 금융시장에 미치는 파급효과를 살펴보는데 초점을 맞춘다. 이를 위해 금융시장의 전반적인 여건변화를 반영하는 금융여건지수(FCI)를 이용하여 미국의 금융시장 여건의 변화가 한국 금융시장의 환율, 채권, 주식에 미치는 영향을 세 금융변수의 수익률과 수익률의 변동성 관점에서 살펴보았다. 월별자료를 이용하여 3-변량 GARCH모형을 추정한 결과, 미국금융여건의 변화는 환율 및 주식의 수익률에는 상당한 부(‑)의 영향을 끼치나 채권의 수익률에는 영향을 미치지 못하고 환율, 주식, 채권 수익률의 변동성에는 거의 영향을 주지 못하는 것으로 나타났다. 단일 금융시장 변수를 이용하여 한국금융시장에 미치는 영향을 분석할 경우 FCI를 이용할 경우보다 과소평가의 가능성이 관찰되었다. 또한 강건성 분석(Robust Analysis)을 시도한 결과, FCI의 산출방법이 다르더라도 실증분석 결과는 질적인 차이가 거의 없는 것으로 나타났다. 본 연구는 거시건전성을 통해 금융시장의 안정을 추구하려는 중앙은행은 미국 금융시장의 여건변화가 한국 개별 금융시장에 미치는 영향이 상이함을 고려하여 정책을 펼 칠 필요가 있음을 시사한다. English Abstract: Existing literature has taken an approach in which the effect of the shock to only individual foreign financial market on domestic financial markets is considered―the contagion effect of asset prices or the transmission effect between international stock markets―in order to examine how the shock to one country financial market affects other country financial markets. This study takes new approach in which the effect of the change in overall financial conditions on other country financial markets is focused on. For this end, we employ the financial condition index (FCI) which reflects overall financial conditions and analyze how the change in US FCI affects Korea foreign exchange, bond and stock markets in terms of the return and its' volatility of exchange rate, bond price, and stock price. We use monthly data and estimate 3-variables GARCH model. The empirical results show that the change in USA financial conditions has an negative impact on the returns of foreign exchange and stock while it does not affect bond's return. The volatility of the return of all three financial variables appears not to be affected by the US FCI. If the change in US stock price was only considered in order to examine the effect of US financial market on Korea financial markets, it was observed that the effect has been underestimated. In addition, as the result of robust analysis, the fundamental results have not been changed when different FCI was used. The result of this study suggests that the Bank of Korea needs to conducts macro-prudential policy in order to stabilize Korea financial market with bearing in mind that the effect of the change in US financial conditions has different impact on Korea individual financial market.

In a simple model of job search with belated information, we show that an increase in search costs decreases the expected probability of a quit, if the wage offer distribution possesses a monotonically increasing hazard rate property. The model is then applied to a marital search.

This paper revisits the yield spread's usefulness for predicting future real GDP growth. We show that the contribution of the spread can be decomposed into the effect of expected future changes in short rates and the effect of the term premium. We find that both factors are relevant for predicting real GDP growth but the respective contributions differ. We investigate whether the cyclical behavior of interest rate volatility could account for either or both effects. We find that while volatility displays important correlations with both the term structure of interest rates and GDP, it does not appear to account for the yield spread's usefulness for predicting GDP growth.