We propose a multi-period clearing framework, where the level of systemic risk is mitigated through the provision of liquidity assistance. The interbank liability network evolves stochastically over time, and assets of defaulted banks are sold to qualified banks within the network through a first-price sealed-bid auction. We find that policies targeting systemically important banks are more effective in core-periphery network structures, whereas those maximizing the total liquidity in the system are preferred in random network configurations. We assess sensitivity of systemic risk to variations in interbank liabilities as well as to their correlation structure.
{"title":"Systemic Risk Mitigation in Financial Networks","authors":"A. Capponi, Peng Chen","doi":"10.2139/ssrn.2293426","DOIUrl":"https://doi.org/10.2139/ssrn.2293426","url":null,"abstract":"We propose a multi-period clearing framework, where the level of systemic risk is mitigated through the provision of liquidity assistance. The interbank liability network evolves stochastically over time, and assets of defaulted banks are sold to qualified banks within the network through a first-price sealed-bid auction. We find that policies targeting systemically important banks are more effective in core-periphery network structures, whereas those maximizing the total liquidity in the system are preferred in random network configurations. We assess sensitivity of systemic risk to variations in interbank liabilities as well as to their correlation structure.","PeriodicalId":414741,"journal":{"name":"Econometric Modeling: Financial Markets Regulation eJournal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129197300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Given the structural differences in banking sector and financial regulation at country level in European Economic and Monetary Union (EMU), this paper tries to estimate the banking sector risk behavior at country level. Based on contingent claim literature, it computes “Distance-to-default (DtD)” at bank level and analyzes the aggregate series at country level for a representative set of banks over the period 2004-Q4 to 2013-Q2. The indices provide an intuitive, forward-looking and timely risk measure having strong correlations with national/regional market sentiment indicators. An underlying trend exists, but causality tests suggest no systemic component. Cross-sectional differences in DtD suggests fragility in EMU countries 12–18 months prior to the crisis and better predictive ability than the regulatory index based on large and complex banking institutions at European level. Furthermore, we explore the reasons for this divergence using VAR estimates.
{"title":"Bank Risk Behavior and Connectedness in EMU Countries","authors":"M. Singh, Marta Gómez-Puig, S. Sosvilla‐Rivero","doi":"10.2139/ssrn.2620204","DOIUrl":"https://doi.org/10.2139/ssrn.2620204","url":null,"abstract":"Given the structural differences in banking sector and financial regulation at country level in European Economic and Monetary Union (EMU), this paper tries to estimate the banking sector risk behavior at country level. Based on contingent claim literature, it computes “Distance-to-default (DtD)” at bank level and analyzes the aggregate series at country level for a representative set of banks over the period 2004-Q4 to 2013-Q2. The indices provide an intuitive, forward-looking and timely risk measure having strong correlations with national/regional market sentiment indicators. An underlying trend exists, but causality tests suggest no systemic component. Cross-sectional differences in DtD suggests fragility in EMU countries 12–18 months prior to the crisis and better predictive ability than the regulatory index based on large and complex banking institutions at European level. Furthermore, we explore the reasons for this divergence using VAR estimates.","PeriodicalId":414741,"journal":{"name":"Econometric Modeling: Financial Markets Regulation eJournal","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123995166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper deals with the origin and the evolution of the European system of fiscal rules and discusses the perspectives for future developments. The early debate about the design of establishing a monetary union in a not optimal currency area, with decentralized fiscal policies, is reconsidered. The main developments of the European rulesDbased fiscal governance are discussed, starting with the Maastricht Treaty and going through the institution and the evolution of the Stability and Growth Pact (SGP). After drawing a brief outline of the system of fiscal rules in force at present, the key issue of the estimation of potential output is considered. The shortcomings of the estimation practices are, to a large extent, responsible for the inadequate results produced by the shift from nominal to structural targets, which was the main aim of the SGP reforms. The paper concludes sketching the debate on the reform of the European economic governance.
{"title":"The Crisis of Economic Governance in the European Union","authors":"Ernesto Longobardi","doi":"10.2139/ssrn.2670556","DOIUrl":"https://doi.org/10.2139/ssrn.2670556","url":null,"abstract":"This paper deals with the origin and the evolution of the European system of fiscal rules and discusses the perspectives for future developments. The early debate about the design of establishing a monetary union in a not optimal currency area, with decentralized fiscal policies, is reconsidered. The main developments of the European rulesDbased fiscal governance are discussed, starting with the Maastricht Treaty and going through the institution and the evolution of the Stability and Growth Pact (SGP). After drawing a brief outline of the system of fiscal rules in force at present, the key issue of the estimation of potential output is considered. The shortcomings of the estimation practices are, to a large extent, responsible for the inadequate results produced by the shift from nominal to structural targets, which was the main aim of the SGP reforms. The paper concludes sketching the debate on the reform of the European economic governance.","PeriodicalId":414741,"journal":{"name":"Econometric Modeling: Financial Markets Regulation eJournal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129540670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In 2007-08, the world experienced the greatest financial crisis since 1929, which turned – in the following years – in one of the deepest and most prolonged periods of economic stagnation of modern history. While there were multiple conditions that originated the so-called Great Financial Crisis, a general consensus emerged that financial derivatives played an important role in the outbreak of the crisis and in posing a credible threat that the entire global financial system could melt down. As a reaction, several countries in the world and international organizations agreed on a policy response to reformulate the global architecture for the regulation of the financial system, including the financial derivatives industry. Yet, the fundamental question of whether the contemporary system of derivatives regulation can effectively shield the financial system from sources of systemic risk is still undecided, for reasons that especially relate to the complexity of the networked structure of the financial derivatives industry. As a way to contribute to tackle this issue, this work aims to investigate whether an important component part of the present system of financial derivatives regulation – namely, Central Counterparts (CCPs) Clearing Houses – provide a more resilient financial system. The research question is addressed through a simulation approach based on an agent-based modeling of the financial derivatives industry. The results of the simulation show that the introduction of a CCP improves the resilience of the simulated financial derivatives industry, although it does not completely shield the financial system from disruptions that may especially depend from the degree of interconnectedness of financial operators and the magnitude of defaults. In sum, this work offers some methodological guidance for enriching the repertoire of tools at disposal of financial regulatory authorities in anticipating the consequences of interventions in the financial industry.
{"title":"The Regulation of Financial Derivatives: An Agent-Based Model Approach.","authors":"Inna Krachkovskaya","doi":"10.2139/SSRN.2610681","DOIUrl":"https://doi.org/10.2139/SSRN.2610681","url":null,"abstract":"In 2007-08, the world experienced the greatest financial crisis since 1929, which turned \u0000– in the following years – in one of the deepest and most prolonged periods of economic \u0000stagnation of modern history. While there were multiple conditions that originated the \u0000so-called Great Financial Crisis, a general consensus emerged that financial derivatives \u0000played an important role in the outbreak of the crisis and in posing a credible threat that \u0000the entire global financial system could melt down. As a reaction, several countries in \u0000the world and international organizations agreed on a policy response to reformulate the \u0000global architecture for the regulation of the financial system, including the financial \u0000derivatives industry. Yet, the fundamental question of whether the contemporary system \u0000of derivatives regulation can effectively shield the financial system from sources of \u0000systemic risk is still undecided, for reasons that especially relate to the complexity of \u0000the networked structure of the financial derivatives industry. As a way to contribute to \u0000tackle this issue, this work aims to investigate whether an important component part of \u0000the present system of financial derivatives regulation – namely, Central Counterparts \u0000(CCPs) Clearing Houses – provide a more resilient financial system. The research \u0000question is addressed through a simulation approach based on an agent-based modeling \u0000of the financial derivatives industry. The results of the simulation show that the \u0000introduction of a CCP improves the resilience of the simulated financial derivatives \u0000industry, although it does not completely shield the financial system from disruptions \u0000that may especially depend from the degree of interconnectedness of financial operators \u0000and the magnitude of defaults. In sum, this work offers some methodological guidance \u0000for enriching the repertoire of tools at disposal of financial regulatory authorities in \u0000anticipating the consequences of interventions in the financial industry.","PeriodicalId":414741,"journal":{"name":"Econometric Modeling: Financial Markets Regulation eJournal","volume":"145 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114762250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Banks around the world suffered huge trading losses in the recent crisis. In response, the Basel Committee on Banking Supervision (2011a) provides a revised framework to determine the minimum capital requirements for their trading portfolios. Moreover, the Dodd-Frank Wall Street Reform and Consumer Protection Act (2010) imposes certain restrictions on the composition of the trading portfolios of U.S. banks through the ‘Volcker Rule.’ Our paper assesses the effectiveness of the Basel framework and the Volcker Rule in preventing banks from taking substantive tail risk in their trading portfolios without capital requirement penalties. We find that the Basel framework is ineffective in preventing banks from doing so, but that the Volcker Rule is beneficial in that it partially mitigates this ineffectiveness. We also suggest two alternatives to the Basel framework and discuss the impact of the Volcker Rule if either one of them is adopted.
{"title":"On Regulatory Responses to the Recent Crisis: An Assessment of the Basel Market Risk Framework and the Volcker Rule","authors":"G. J. Alexander, Alexandre M. Baptista, Shu Yan","doi":"10.1111/fmii.12025","DOIUrl":"https://doi.org/10.1111/fmii.12025","url":null,"abstract":"Banks around the world suffered huge trading losses in the recent crisis. In response, the Basel Committee on Banking Supervision (2011a) provides a revised framework to determine the minimum capital requirements for their trading portfolios. Moreover, the Dodd-Frank Wall Street Reform and Consumer Protection Act (2010) imposes certain restrictions on the composition of the trading portfolios of U.S. banks through the ‘Volcker Rule.’ Our paper assesses the effectiveness of the Basel framework and the Volcker Rule in preventing banks from taking substantive tail risk in their trading portfolios without capital requirement penalties. We find that the Basel framework is ineffective in preventing banks from doing so, but that the Volcker Rule is beneficial in that it partially mitigates this ineffectiveness. We also suggest two alternatives to the Basel framework and discuss the impact of the Volcker Rule if either one of them is adopted.","PeriodicalId":414741,"journal":{"name":"Econometric Modeling: Financial Markets Regulation eJournal","volume":"410 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"119681752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Since the mid-1990s, many OECD countries have experienced a substantial increase in household indebtedness. Sweden, in particular, has seen indebtedness rise from 90% of disposable income in 1995 to 179% in 2015. The Swedish Financial Supervisory Authority (FSA) has identified mortgage amortization requirements as a potential instrument for reducing indebtedness; and has drafted guidelines that will intensify the rate and duration of amortization. In this paper, I characterize Swedish-style mortgage contracts, which differ substantially from U.S.-style contracts. I then evaluate the policy changes in an incomplete markets model with three types of debt and a novel mortgage contract specification that is calibrated to match Swedish micro and macro data. I find that intensifying the rate and duration of amortization is largely ineffective at reducing indebtedness in a realistically-calibrated model. In the absence of tight restrictions on the maximum debt-service-to-income ratio or implausibly large refinancing costs, the policy impact is small in aggregate, over the lifecycle, and across employment statuses.
{"title":"Amortization Requirements and Household Indebtedness: An Application to Swedish- Style Mortgages","authors":"Isaiah Hull","doi":"10.2139/ssrn.2635373","DOIUrl":"https://doi.org/10.2139/ssrn.2635373","url":null,"abstract":"Since the mid-1990s, many OECD countries have experienced a substantial increase in household indebtedness. Sweden, in particular, has seen indebtedness rise from 90% of disposable income in 1995 to 179% in 2015. The Swedish Financial Supervisory Authority (FSA) has identified mortgage amortization requirements as a potential instrument for reducing indebtedness; and has drafted guidelines that will intensify the rate and duration of amortization. In this paper, I characterize Swedish-style mortgage contracts, which differ substantially from U.S.-style contracts. I then evaluate the policy changes in an incomplete markets model with three types of debt and a novel mortgage contract specification that is calibrated to match Swedish micro and macro data. I find that intensifying the rate and duration of amortization is largely ineffective at reducing indebtedness in a realistically-calibrated model. In the absence of tight restrictions on the maximum debt-service-to-income ratio or implausibly large refinancing costs, the policy impact is small in aggregate, over the lifecycle, and across employment statuses.","PeriodicalId":414741,"journal":{"name":"Econometric Modeling: Financial Markets Regulation eJournal","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127053453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We provide a welfare comparison of the two types of banking regulation commonly used to address moral hazard problems, deposit rate ceilings and minimum capital requirements. It is well understood that interference with the price mechanism may lead to inefficiencies -- in the case of a deposit rate ceiling, the expected consequence is financial repression and possibly migration of depositors to unregulated financial institutions. As was already pointed out by Besanko and Thakor (1992), minimum capital requirements are, however, likely to have similar effects, since banks will pass the costs of this regulation on to depositors in the form of lower interest rates. Possibly for this reason there seem to be no theoretical studies supporting the reforms in the 80's and 90's, which saw deposit rate ceilings being replaced by minimum capital requirements. Either the two instruments are considered for all practical purposes equivalent or the conclusion is in favor of deposit regulation. In our model, while both types of regulation may depress deposit rates, there is a real trade-off between the two: capital regulation is costly because the opportunity costs of capital is higher than the return from normal banking activities while deposit rate ceilings may result in an inefficiently high number of banks. We show that, depending on the opportunity costs of banking capital and on the severity of the moral hazard problem they seek to address, each of the two regulatory instruments may welfare dominate the other.
{"title":"Bank Regulation When Both Deposit Rate Control and Capital Requirements are Socially Costly","authors":"C. Nielsen, G. Weinrich","doi":"10.2139/ssrn.2685643","DOIUrl":"https://doi.org/10.2139/ssrn.2685643","url":null,"abstract":"We provide a welfare comparison of the two types of banking regulation commonly used to address moral hazard problems, deposit rate ceilings and minimum capital requirements. It is well understood that interference with the price mechanism may lead to inefficiencies -- in the case of a deposit rate ceiling, the expected consequence is financial repression and possibly migration of depositors to unregulated financial institutions. As was already pointed out by Besanko and Thakor (1992), minimum capital requirements are, however, likely to have similar effects, since banks will pass the costs of this regulation on to depositors in the form of lower interest rates. Possibly for this reason there seem to be no theoretical studies supporting the reforms in the 80's and 90's, which saw deposit rate ceilings being replaced by minimum capital requirements. Either the two instruments are considered for all practical purposes equivalent or the conclusion is in favor of deposit regulation. In our model, while both types of regulation may depress deposit rates, there is a real trade-off between the two: capital regulation is costly because the opportunity costs of capital is higher than the return from normal banking activities while deposit rate ceilings may result in an inefficiently high number of banks. We show that, depending on the opportunity costs of banking capital and on the severity of the moral hazard problem they seek to address, each of the two regulatory instruments may welfare dominate the other.","PeriodicalId":414741,"journal":{"name":"Econometric Modeling: Financial Markets Regulation eJournal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125513512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tracing the SEC ban on the short selling of financial stocks in September 2008, this paper investigates whether such selling activity before the 2008 short ban reflected financial companies’ risk exposures in the subprime crisis. The evidence suggests that short sellers sold short stocks that had the greatest asset and insolvency risk exposures, and that the short selling of financial firms’ stocks was not significantly greater than that of non-financial firms. When the short ban was in effect, the market quality of financial stocks without subprime asset exposure had deteriorated to a larger degree than that of financial companies with subprime asset exposure. The findings imply that such a regulation may mute the market disciplining effects of investors and may also serve as a counterweight to any perceived macro or systemic risk reduction benefits resulting from such a ban.
{"title":"Which Financial Stocks Did Short Sellers Target in the Subprime Crisis?","authors":"I. Hasan, Nadia Massoud, A. Saunders, Keke Song","doi":"10.2139/ssrn.2570847","DOIUrl":"https://doi.org/10.2139/ssrn.2570847","url":null,"abstract":"Tracing the SEC ban on the short selling of financial stocks in September 2008, this paper investigates whether such selling activity before the 2008 short ban reflected financial companies’ risk exposures in the subprime crisis. The evidence suggests that short sellers sold short stocks that had the greatest asset and insolvency risk exposures, and that the short selling of financial firms’ stocks was not significantly greater than that of non-financial firms. When the short ban was in effect, the market quality of financial stocks without subprime asset exposure had deteriorated to a larger degree than that of financial companies with subprime asset exposure. The findings imply that such a regulation may mute the market disciplining effects of investors and may also serve as a counterweight to any perceived macro or systemic risk reduction benefits resulting from such a ban.","PeriodicalId":414741,"journal":{"name":"Econometric Modeling: Financial Markets Regulation eJournal","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127096828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT: We examine contagion in earnings management using 2,376 restatements announced during the years 1997–2008. Controlling for industry and firm characteristics, firms are more likely to begi...
{"title":"Evidence on Contagion in Earnings Management","authors":"Simi Kedia, Kevin Koh, Shivaram Rajgopal","doi":"10.2139/ssrn.2562751","DOIUrl":"https://doi.org/10.2139/ssrn.2562751","url":null,"abstract":"ABSTRACT: We examine contagion in earnings management using 2,376 restatements announced during the years 1997–2008. Controlling for industry and firm characteristics, firms are more likely to begi...","PeriodicalId":414741,"journal":{"name":"Econometric Modeling: Financial Markets Regulation eJournal","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132301416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper connects variance-covariance estimation methods, Gaussian graph- ical models, and the growing literature on economic and nancial networks. We construct the network using the concept of partial correlations which captures direct linear depen- dence between any two entities, conditional on dependence between all other entities. We relate the centrality measures of this network to shock propagation. The methodology is applied to construct the perceived network of the publicly traded Australian banks and their connections to the domestic nancial sector, real economy, and international mar- kets. We nd strong links between the big four Australian banks, the nancial services sector and the other sectors of the economy and determine which entities play a central role in transmitting and absorbing the shocks.
{"title":"Connecting the Dots: Econometric Methods for Uncovering Networks with an Application to the Australian Financial Institutions","authors":"M. Anufriev, V. Panchenko","doi":"10.2139/ssrn.2560594","DOIUrl":"https://doi.org/10.2139/ssrn.2560594","url":null,"abstract":"This paper connects variance-covariance estimation methods, Gaussian graph- ical models, and the growing literature on economic and nancial networks. We construct the network using the concept of partial correlations which captures direct linear depen- dence between any two entities, conditional on dependence between all other entities. We relate the centrality measures of this network to shock propagation. The methodology is applied to construct the perceived network of the publicly traded Australian banks and their connections to the domestic nancial sector, real economy, and international mar- kets. We nd strong links between the big four Australian banks, the nancial services sector and the other sectors of the economy and determine which entities play a central role in transmitting and absorbing the shocks.","PeriodicalId":414741,"journal":{"name":"Econometric Modeling: Financial Markets Regulation eJournal","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126733033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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