• Title/Summary/Keyword: critical period hypothesis

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COVID-19, Remittance Inflows, and the Stock Market: Empirical Evidence from Bangladesh

  • QAMRUZZAMAN, Md.;KARIM, Salma;JAHAN, Ishrat
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.5
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    • pp.265-275
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    • 2021
  • This study's motivation is to investigate the association between the stock market, remittance, and the pandemic of COVID-19 for the period from March 3, 2020, to December 14, 2020. For evaluating the impact of COVID-19 and remittances on stock market behaviour during the pandemic, the study applies Autoregressive Distributed lagged (ARDL) for magnitudes estimation and directional association through the Toda-Yamamoto causality test. Study findings from ARDL estimation revealed that COVID-19 measured by detecting new cases negatively influences the stock market both in the long-term and short-term. Remittance positively influences the stock market behaviour, particularly in the long-term. Furthermore, the directional causality test disclosed unidirectional causal effects between COVID-19 and the stock market behaviour, which establishes all proxy measures for the equation's stock market. The hypothesis results explain the causal relationship between remittance inflows and the stock market in Bangladesh. The study's application will help policymakers rethink the policies for channelizing remittances for productive investment areas. Furthermore, the study's findings will reinstate the widely perceived notions, which is the critical role of remittance in the economy even though the economy passes through a great pandemic.

Earnings Management, Uncertainty and the Role of Conservative Financial Reporting: Empirical Evidence from Pakistan

  • FATIMA, Huma;HAQUE, Abdul;QAMMAR, Muhammad Ali Jibran
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.4
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    • pp.39-52
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    • 2022
  • This study examines whether accounting conservatism can support real earnings management by reducing accrual earnings management techniques. The net impact of conservative reporting on earnings management is also analyzed. It is assumed that moderating the role of conservative financial reporting during uncertainty can mitigate earnings management practices. For our analysis, 5354 firm-year observations for the period 2007-2020 of nonfinancial companies listed on the Pakistan Stock Exchange are applied. To measure conservatism in the non-financial sector of Pakistan, Khan and Watts' (2009) model is used to provide evidence that conservatism is a way to restrict earnings management during uncertainty. "Prospector" and "Defender" Business strategy is applied for measuring firm-level uncertainty. To measure accrual earnings management Modified Jones (1995) model and Dechow and Dichev (2002) approach and Kasznik (1999) model are applied, and for real earnings management Roychowdhury model is applied which follows three approaches to measure real earnings management i.e. cash flow manipulation, Overproduction, and discretionary expenses. The estimations support our hypothesis by providing statistically significant proof that conservative financial reporting in a developing economy like Pakistan may be used to overcome the net impact of earnings management during uncertainty. Our results provide critical and practical implications for investors, researchers, and standard setters.

Spatial Data Analysis for the U.S. Regional Income Convergence,1969-1999: A Critical Appraisal of $\beta$-convergence (미국 소득분포의 지역적 수렴에 대한 공간자료 분석(1969∼1999년) - 베타-수렴에 대한 비판적 검토 -)

  • Sang-Il Lee
    • Journal of the Korean Geographical Society
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    • v.39 no.2
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    • pp.212-228
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    • 2004
  • This paper is concerned with an important aspect of regional income convergence, ${\beta}$-convergence, which refers to the negative relationship between initial income levels and income growth rates of regions over a period of time. The common research framework on ${\beta}$-convergence which is based on OLS regression models has two drawbacks. First, it ignores spatially autocorrelated residuals. Second, it does not provide any way of exploring spatial heterogeneity across regions in terms of ${\beta}$-convergence. Given that empirical studies on ${\beta}$-convergence need to be edified by spatial data analysis, this paper aims to: (1) provide a critical review of empirical studies on ${\beta}$-convergence from a spatial perspective; (2) investigate spatio-temporal income dynamics across the U.S. labor market areas for the last 30 years (1969-1999) by fitting spatial regression models and applying bivariate ESDA techniques. The major findings are as follows. First, the hypothesis of ${\beta}$-convergence was only partially evidenced, and the trend substantively varied across sub-periods. Second, a SAR model indicated that ${\beta}$-coefficient for the entire period was not significant at the 99% confidence level, which may lead to a conclusion that there is no statistical evidence of regional income convergence in the US over the last three decades. Third, the results from bivariate ESDA techniques and a GWR model report that there was a substantive level of spatial heterogeneity in the catch-up process, and suggested possible spatial regimes. It was also observed that the sub-periods showed a substantial level of spatio-temporal heterogeneity in ${\beta}$-convergence: the catch-up scenario in a spatial sense was least pronounced during the 1980s.

The Impact of Disclosure Quality on Crash Risk: Focusing on Unfaithful Disclosure Firms (공시품질이 주가급락에 미치는 영향: 불성실공시 지정기업을 대상으로)

  • RYU, Hae-Young
    • The Journal of Industrial Distribution & Business
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    • v.10 no.6
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    • pp.51-58
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    • 2019
  • Purpose - Prior studies reported that the opacity of information caused stock price crash. If managers fail to disclose unfavorable information about the firm over a long period of time, the stock price is overvalued compared to its original value. If the accumulated information reaches a critical point and spreads quickly to the market, the stock price plunges. Information management by management's disclosure policy can cause information uncertainty, which will lead to a plunge in stock prices in the future. Thus, this study aims at examining the impact of disclosure quality on crash risk by focusing on the unfaithful disclosure firms. Research design, data, and methodology - This study covers firms listed on KOSPI and KOSDAQ from 2004 to 2013. Firms excluded from the sample are non-December firms, capital-eroding firms, and financial firms. The financial data used in the research was extracted from the KIS-Value and TS2000 database. Unfaithful disclosure firm designation data was collected from the Korea Exchange's electronic disclosure system (kind.krx.co.kr). Stock crash is measured as a dummy variable that equals one if a firm experiences at least one crash week over the fiscal year, and zero otherwise. Results - Empirical results as to the relation between unfaithful disclosure corporation designation and stock price crashes are as follows: There was a significant positive association between unfaithful disclosure corporation designation and stock price crash. This result supports the hypothesis that firms that have previously exhibited unfaithful disclosure behavior are more likely to suffer stock price plunges due to information asymmetry. Second, stock price crashes due to unfaithful disclosures are more likely to occur in Chaebol firms. Conclusions - While previous studies used estimates as a proxy for information opacity, this study used an objective measure such as unfaithful disclosure corporation designation. The designation by Korea Exchange is an objective evidence that the firm attempted to conceal and distort information in the previous year. The results of this study suggest that capital market investors need to investigate firms' disclosure behaviors.

Oxyradical Formation during the Hepatocarcinogenesis in Rat (흰쥐 간발암화 과정에서의 산소유리기의 동태)

  • Kim, Hyoung-Chun;Chun, Wan-Jhoo;Lee, Hyun-Woo;Kwon, Myung-Sang;Song, Kye-Yong;Jhoo, Wang-Kee
    • YAKHAK HOEJI
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    • v.36 no.2
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    • pp.180-187
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    • 1992
  • This study investigated the hypothesis that carcinogen-induced elevation of oxyradical during the hepatocarcinogenesis in rat. The hepatic preneoplastic lesions in the Spraque-Dawley rats were induced by the carcinogen treatment such as diethylnitrosamine(DEN) and acetylaminofluorene(AAF) in combination with partial hepatectomy(PH). The liver sample was taken at 2, 6, 10 and 16 months after carcinogen treatments followed by PH. Carcinogen treatments initially increased the indices of oxidative damage(activities of xanthine oxidase and production rates of superoxide anion, microsomal hydrogen peroxide, hydroxyl radical) in the liver compared to PH groups. However, cytosolic hydrogen peroxide did not change significantly throughout the full time period. Of hydrogen peroxide scavenger, the catalase was remained lower than PH groups, whereas the peroxidase was increased after carcinogen treatments. Morphologically, the immunohistochemical analysis with glutathione-S-transferase of a placenta form(GSTP) antibody was used to detect the induction of preneoplastic nodules. During the hepatocarcinogenesis, both production rate of hydroxyl radical and activity of glutathione-S-transferase(GST) markedly increased with the appearance of the preneoplastic nodule. These results indicated that the hydroxyl radical of reactive oxygen species seemed to have a major influence on the hepatocarcinogenesis and the effect of time after removal of the carcinogen also appeared to be highly critical in the hepatocarcinogenesis.

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Clinical Significance of Low-colony Count Scotochromogen Nontuberculous Mycobacteria (균집락수가 적은 암색소성 비결핵항산균 배양의 임상적 의미)

  • Lee, Jung Yeon;Kim, Mi-Na;Chung, Hee-Jung;Jun, Kyung Ran;Choi, Hee Jin;Lee, Hyeyoung;Joung, Eun Young;Oh, Yeon-Mok;Lee, Sang Do;Kim, Woo Sung;Kim, Dong Soon;Kim, Won Dong;Shim, Tae Sun
    • Tuberculosis and Respiratory Diseases
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    • v.59 no.1
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    • pp.39-46
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    • 2005
  • Background : Even though it has been suggested that low-colony, scotochromogen nontuberculous mycobacteria (NTM) are usually contaminants and not true pathogens, evidence for this hypothesis has not been provided. This study investigated the colony characteristics, organism identification, and clinical significance of low-colony scotochromogen. Methods : The laboratory cultured 6,898 respiratory clinical specimens for an examination of mycobacteria over a three-month period. A low-colony count was arbitrarily defined as ${\leq}20$ colonies. This study analyzed the recovery rate of the mycobacteria, the number of colonies and their gross characteristics, and their clinical significance. PCR-restriction fragment length polymorphism analysis was carried out to identify the NTM species. NTM pulmonary disease was defined according to the American Thoracic Society. Results : A total of 6,898 respiratory specimens for mycobacterium were cultured. Of these, 263 (3.8%) grew NTM, and 382 (5.5%) grew M. tuberculosis. Of the 263 cultured NTM specimens, 124 (47.1%) were scotochromogens. The smear-positive rate was significantly lower in these scotochromogens (4.8%) than in the non-scotochromogens (23.7%) (p<0.05). The most common isolates were M. gordonae (83/102, 81.4%) in the scotochromogens, and MAC (52/121, 43.0%) in the non-scotochromogens. Even though three out of 113 patients with a low-colony scotochromogen has been diagnosed with NTM pulmonary disease, the isolated scotochromogen was not considered to be the cause of the NTM disease but was just a contaminant. Conclusion : In this study, the most common isolate of a low-colony count scotochromogen was M. gordonae, which appeared to be contaminants and not true pathogens. Greater efforts in the quality control of a mycobacterium laboratory are needed in cases where there is a high recovery rate of low-colony count scotochromogen.

EXPRESSION OF BMP-2, -4 DURING DISTRACTION OSTEOGENESIS IN THE RABBIT MANDIBLE (집토끼 하악골에서 신연 골형성술시 BMP-2,-4의 발현)

  • Kim, Sang-Woo;Jee, Yu-Jin;Song, Hyun-Chul
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.30 no.3
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    • pp.193-202
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    • 2004
  • Distraction osteogenesis(DO) is defined as a gradual mechanical process of mechanical stretching two vascularized bone surface apart with a critical rate and rhythm such that new bone forms within the expanding gap, reliably bridges the gap, and ultimately remodels to normal structure. DO has become a mainstay in bone tissue engineering and has significantly improved our armamentarium for reconstructive craniomaxillofacial procedures. But the molecular and biological mechanisms that regulate the formation of new bone during distraction osteogenesis are not completely understood. BMPs are potent osteoinductive agents. Our hypothesis was that BMPs, especially BMP-2 and BMP-4, might play an importent role in the signaling pathways that link the mechanical forces created by distraction to biological responses and in promting new bone formation. Using a rabbit's mandible, we investigated the expression of BMP-2, -4 at different time points during distraction osteogenesis. The purpose of this study is to research the pattern of expression of BMP-2, -4 in new bone formation during distraction osteogenesis of the rabbit mandible. The experimental group was applied gradual distraction (0.7mm a day by twice a day, 4.9mm in total, for 7 days) and the control group was carried out osteotomy alone. They were examined clinically, histologically, and by RT-PCR analysis. On 3 days after osteotomy, the high level of expression of BMP-2, -4 was detected. But, the expression of BMP-4 was decreased during latency period. As distraction was started, its expression was increased and maintained till postoperative 28days. In control group, the expression of BMP-4was remarkably decreased till postoperative 14 days. On the other hand, the expression of BMP-2 was no difference between experimental group and control group. The expression of BMP-4 was maintanined at high level during the entire experimental period in both group. These findings suggested that excellent bone formation during distraction osteogenesis is associated with enhanced expression of BMP-4 genes by mechanical tension stress.

Product Community Analysis Using Opinion Mining and Network Analysis: Movie Performance Prediction Case (오피니언 마이닝과 네트워크 분석을 활용한 상품 커뮤니티 분석: 영화 흥행성과 예측 사례)

  • Jin, Yu;Kim, Jungsoo;Kim, Jongwoo
    • Journal of Intelligence and Information Systems
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    • v.20 no.1
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    • pp.49-65
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    • 2014
  • Word of Mouth (WOM) is a behavior used by consumers to transfer or communicate their product or service experience to other consumers. Due to the popularity of social media such as Facebook, Twitter, blogs, and online communities, electronic WOM (e-WOM) has become important to the success of products or services. As a result, most enterprises pay close attention to e-WOM for their products or services. This is especially important for movies, as these are experiential products. This paper aims to identify the network factors of an online movie community that impact box office revenue using social network analysis. In addition to traditional WOM factors (volume and valence of WOM), network centrality measures of the online community are included as influential factors in box office revenue. Based on previous research results, we develop five hypotheses on the relationships between potential influential factors (WOM volume, WOM valence, degree centrality, betweenness centrality, closeness centrality) and box office revenue. The first hypothesis is that the accumulated volume of WOM in online product communities is positively related to the total revenue of movies. The second hypothesis is that the accumulated valence of WOM in online product communities is positively related to the total revenue of movies. The third hypothesis is that the average of degree centralities of reviewers in online product communities is positively related to the total revenue of movies. The fourth hypothesis is that the average of betweenness centralities of reviewers in online product communities is positively related to the total revenue of movies. The fifth hypothesis is that the average of betweenness centralities of reviewers in online product communities is positively related to the total revenue of movies. To verify our research model, we collect movie review data from the Internet Movie Database (IMDb), which is a representative online movie community, and movie revenue data from the Box-Office-Mojo website. The movies in this analysis include weekly top-10 movies from September 1, 2012, to September 1, 2013, with in total. We collect movie metadata such as screening periods and user ratings; and community data in IMDb including reviewer identification, review content, review times, responder identification, reply content, reply times, and reply relationships. For the same period, the revenue data from Box-Office-Mojo is collected on a weekly basis. Movie community networks are constructed based on reply relationships between reviewers. Using a social network analysis tool, NodeXL, we calculate the averages of three centralities including degree, betweenness, and closeness centrality for each movie. Correlation analysis of focal variables and the dependent variable (final revenue) shows that three centrality measures are highly correlated, prompting us to perform multiple regressions separately with each centrality measure. Consistent with previous research results, our regression analysis results show that the volume and valence of WOM are positively related to the final box office revenue of movies. Moreover, the averages of betweenness centralities from initial community networks impact the final movie revenues. However, both of the averages of degree centralities and closeness centralities do not influence final movie performance. Based on the regression results, three hypotheses, 1, 2, and 4, are accepted, and two hypotheses, 3 and 5, are rejected. This study tries to link the network structure of e-WOM on online product communities with the product's performance. Based on the analysis of a real online movie community, the results show that online community network structures can work as a predictor of movie performance. The results show that the betweenness centralities of the reviewer community are critical for the prediction of movie performance. However, degree centralities and closeness centralities do not influence movie performance. As future research topics, similar analyses are required for other product categories such as electronic goods and online content to generalize the study results.

Disruption of Sphingolipid Metabolism as a Potential Mechanism of Fumonisin Inhibition of Cell Growth in $LLC-PK_1$ Cells

  • Yoo, Hwan-Soo;Yun, Yeo-Pyo
    • Toxicological Research
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    • v.11 no.1
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    • pp.1-8
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    • 1995
  • Fumonisins are a family of mycotoxins produced by the fungus Fusarium moniliforme which is a common contaminant in corn. Fumonisins are potent inhibitors of sphingosine and sphinganine N-acyltransferase (ceramide synthase), key enzymes in sphingolipid metabolism. The purpose of this study was to provide the evidence that the elevated levels of free sphingoid bases (primarily sphinganine) and depletion of complex sphingolipids were closely related to the inhibition of cell growth in LLC-$PK_1$ cells exposed to fumonisin $B_1$$(\leq 35 {\mu}M)$. Concentrations of fumonisin $B_1$ between 10 and $35 {\mu}M$ were known to inhibit cell growth without cytotoxicity in $LLC-PK_1$ cells (Yoo et al. Toxicol. Appl. Pharmacol. 114, 9-15, 1992). Cells exposed to 35$\mu M$ fumonisin B$_1$ for 48 and 72 hr developed a fibroblast-like (elongated and spindle-shaped) appearance and were less confluent than normal cells. At between 24 and 48 hr after exposure to fumonisin $B_1$ cells were beginning to show the inhibition of cell growth and at 72 hr the number of viable cells in fumonisin-treated cultures was about 50% of concurrent control cultures. During the 24 hr lag period preceding inhibition of cell growth, the free sphinganine levels in cells exposed to $35 {\mu}M$ fumonisin $B_1$ were highly elevated (approximately 230 fold higher than normal cells). The elevated levels of free sphinganine were $435\pm14$$pmoles/{10^6}$ cells at 48 hr and approximately TEX>$333\pm11$$pmoles/{10^6}$ cells in cells exposed to $35{\mu}M$ fumonisin$B_1$ at 72 hr, while the levels of free sphinganine in normal cells were less than 2$pmoles/{10^6}$ cells. Under the same condition, depletion of intracellular complex sphingolipids as a consequence of fumonisin inhibition of de novo sphingolipid biosynthesis and turnover pathway was appeared. Content of free sphingold bases in dividing cells was more elevated than in confluent cells at 24-48 hr after cells were exposed to $20{\mu}M$ fumonisin $B_1$. The dividing cells were showing the inhibition of cell growth at 48-72 hr and $20{\mu}M$ fumonisin $B_1$. The results of this study support the hypothesis that the inhibition of cell growth is very well related to the disruption of sphingolipid metabolism in $LLC-PK_1$ cells.

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A Critical Analysis on Social Welfare Researches in Korea (우리나라 사회복지학 연구경향에 관한 연구 - <한국사회복지학>에 실린 경험분석연구를 중심으로 -)

  • Kim, Yoon-Ock
    • Korean Journal of Social Welfare
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    • v.35
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    • pp.85-105
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    • 1998
  • This article examined the trend of 125 empirical researches which were published in Jr. of Korean Social Welfare from the first issue to no. 33. in terms of theoretical and methodological orientations. The content analysis was employed for the purpose of the study. Since 1979, the number of empirical researches was in the trend of increasing. The findings from this research were as follows. 1) Among 166 authors, 96.4% were majored in social welfare. Also 6.0% were practitioners and the rest of them were in the position of professors or researchers. The outcome of lack of interdisciplinary co-work and researcher-practitioner co-work led the article to conclude that the nature of applied social science of social welfare was not so actively pursued in Korea. 2) It was almost impossible to find researches which studied same theme or employed same analytical framework. This meant that the work of re-verifying and proving the contray could not be done although it was essential for theory-building. In other words, the disciplinary of social welfare was far behind in the process of theory-building. 3) The methodology upon which most of researches were relied was quantitative methodology(92.8%). The article concluded 'paradigm shift' was not begun in the disciplinary of social welfare yet. 4) The study concluded that the particularity of empirical researches of social welfare in Korea was descriptive-configurative study. Whereas 65.5% of 125 empirical studies were descriptive-configurative, 25% were hypothesis - model test and only 6% causal analysis. 5) The most applied statistic models through the period from 1979 to 1997 were descriptive statistics such as frequency, chi square test, Pearson's r. More advanced statistics such as logit regression, probit regression, path analysis, covariance structure analysis were shown since 1990.

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