Benjamin Ferschli, Miriam Rehm, M. Schnetzer, S. Zilian
Abstract This paper investigates the links of digitalization and industry concentration with labor productivity at the sectoral level in Germany. Combining data for digitalization and labor productivity from the EU KLEMS database with firm-level data from the CompNet and Orbis Bureau Van Dijk databases to construct industry concentration measures between 2000 and 2015, we show that (1) the German economy appears to have digitized since 2000, and (2) there is no clear-cut relationship between digitalization and market concentration at the industry level. Using a time and sector fixed effects model and controlling for capital intensity, however, we find evidence for (3) a positive effect of both lagged industry concentration and lagged digitalization on productivity at the sectoral level in Germany. This finding is robust to alternative measures of digitalization and industry concentration as well as to their interaction but sensitive to the sector sample and to scale effects from the capital intensity. We, therefore, cautiously conclude that recent technological change appears to have been labor-saving and that productivity-enhancing aspect of a partial “superstar firm” effect may be identified in the German economy, in particular in its manufacturing sector.
摘要本文从部门层面研究了数字化、产业集中度与德国劳动生产率的关系。结合欧盟KLEMS数据库的数字化和劳动生产率数据，以及CompNet和Orbis Bureau Van Dijk数据库的企业层面数据，构建2000年至2015年的行业集中度测度，我们发现:(1)德国经济自2000年以来似乎已经实现了数字化，(2)在行业层面上，数字化与市场集中度之间没有明确的关系。然而，使用时间和部门固定效应模型并控制资本强度，我们发现(3)在德国，落后的产业集中度和落后的数字化对部门层面的生产率都有积极影响。这一发现对数字化和行业集中度的替代指标以及它们之间的相互作用是稳健的，但对行业样本和资本密集度的规模效应敏感。因此，我们谨慎地得出结论，最近的技术变革似乎已经节省了劳动力，并且在德国经济中，特别是在其制造业中，可以确定部分“超级明星公司”效应的提高生产率方面。
{"title":"Digitalization, Industry Concentration, and Productivity in Germany","authors":"Benjamin Ferschli, Miriam Rehm, M. Schnetzer, S. Zilian","doi":"10.1515/jbnst-2020-0058","DOIUrl":"https://doi.org/10.1515/jbnst-2020-0058","url":null,"abstract":"Abstract This paper investigates the links of digitalization and industry concentration with labor productivity at the sectoral level in Germany. Combining data for digitalization and labor productivity from the EU KLEMS database with firm-level data from the CompNet and Orbis Bureau Van Dijk databases to construct industry concentration measures between 2000 and 2015, we show that (1) the German economy appears to have digitized since 2000, and (2) there is no clear-cut relationship between digitalization and market concentration at the industry level. Using a time and sector fixed effects model and controlling for capital intensity, however, we find evidence for (3) a positive effect of both lagged industry concentration and lagged digitalization on productivity at the sectoral level in Germany. This finding is robust to alternative measures of digitalization and industry concentration as well as to their interaction but sensitive to the sector sample and to scale effects from the capital intensity. We, therefore, cautiously conclude that recent technological change appears to have been labor-saving and that productivity-enhancing aspect of a partial “superstar firm” effect may be identified in the German economy, in particular in its manufacturing sector.","PeriodicalId":45967,"journal":{"name":"Jahrbucher Fur Nationalokonomie Und Statistik","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66923934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Vector autoregressions (VARs) are richly parameterized time series models that can capture complex dynamic interrelationships among macroeconomic variables. However, in small samples the rich parametrization of VAR models may come at the cost of overfitting the data, possibly leading to imprecise inference for key quantities of interest such as impulse response functions (IRFs). Bayesian VARs (BVARs) can use prior information to shrink the model parameters, potentially avoiding such overfitting. We provide a simulation study to compare, in terms of the frequentist properties of the estimates of the IRFs, useful strategies to select the informativeness of the prior. The study reveals that prior information may help to obtain more precise estimates of impulse response functions than classical OLS-estimated VARs and more accurate coverage rates of error bands in small samples. Strategies based on selecting the prior hyperparameters of the BVAR building on empirical or hierarchical modeling perform particularly well.
{"title":"A Comparison of Approaches to Select the Informativeness of Priors in BVARs","authors":"Jan Prüser, C. Hanck","doi":"10.1515/jbnst-2020-0050","DOIUrl":"https://doi.org/10.1515/jbnst-2020-0050","url":null,"abstract":"Abstract Vector autoregressions (VARs) are richly parameterized time series models that can capture complex dynamic interrelationships among macroeconomic variables. However, in small samples the rich parametrization of VAR models may come at the cost of overfitting the data, possibly leading to imprecise inference for key quantities of interest such as impulse response functions (IRFs). Bayesian VARs (BVARs) can use prior information to shrink the model parameters, potentially avoiding such overfitting. We provide a simulation study to compare, in terms of the frequentist properties of the estimates of the IRFs, useful strategies to select the informativeness of the prior. The study reveals that prior information may help to obtain more precise estimates of impulse response functions than classical OLS-estimated VARs and more accurate coverage rates of error bands in small samples. Strategies based on selecting the prior hyperparameters of the BVAR building on empirical or hierarchical modeling perform particularly well.","PeriodicalId":45967,"journal":{"name":"Jahrbucher Fur Nationalokonomie Und Statistik","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66923872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper gives a comprehensive introduction to the IOER Monitor – an open research data infrastructure (RDI) in Germany providing domain-specific multi-temporal geospatial datasets, services and visualizations for land use and land cover (LULC)-related development of settlements and open space and closely related topics. Its easy-to-use information system provides multi-scale data offers to form a discussion platform that supports spatial development assessment and evidence-based decision making. It contributes to public land-use change discourses by enhancing information offers that can be adopted by other multi-disciplinary data users - even from non-spatial domains. All data and services are freely available. IOER Monitor is committed to offering continuous services implementing FAIR principles (findable, accessible, interoperable and re-usable) and policy-relevant inputs for transformative spatial development.
{"title":"IOER Monitor: A Spatio-Temporal Research Data Infrastructure on Settlement and Open Space Development in Germany","authors":"G. Meinel, S. K. Sikder, T. Krueger","doi":"10.1515/jbnst-2021-0009","DOIUrl":"https://doi.org/10.1515/jbnst-2021-0009","url":null,"abstract":"Abstract This paper gives a comprehensive introduction to the IOER Monitor – an open research data infrastructure (RDI) in Germany providing domain-specific multi-temporal geospatial datasets, services and visualizations for land use and land cover (LULC)-related development of settlements and open space and closely related topics. Its easy-to-use information system provides multi-scale data offers to form a discussion platform that supports spatial development assessment and evidence-based decision making. It contributes to public land-use change discourses by enhancing information offers that can be adopted by other multi-disciplinary data users - even from non-spatial domains. All data and services are freely available. IOER Monitor is committed to offering continuous services implementing FAIR principles (findable, accessible, interoperable and re-usable) and policy-relevant inputs for transformative spatial development.","PeriodicalId":45967,"journal":{"name":"Jahrbucher Fur Nationalokonomie Und Statistik","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/jbnst-2021-0009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66924471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper presents an analysis of the recent developments of average market power in Europe by using a broad firm-level database for EU member states. To indicate competitive pressure at the firm-level, markups are estimated following De Loecker, J. (2011). Recovering markups from production data. Int. J. Ind. Organ. 29: 350–355, and De Loecker, J. and Warzynski, F. (2012). Markups and firm-level export status. Am. Econ. Rev. 102: 2437–2471. The analysis reveals a sharp drop in markups during the crisis, followed by a post-crisis increase. The European average has not yet reached its pre-crisis level, which is in contrast to results for the US, where average markups have climbed to pre-crisis levels already in 2011. There is significant heterogeneity among European economies and the pre-crisis levels do have been exceeded in some countries.
{"title":"The Fall and Rise of Market Power in Europe","authors":"John P. Weche, A. Wambach","doi":"10.2139/ssrn.3109442","DOIUrl":"https://doi.org/10.2139/ssrn.3109442","url":null,"abstract":"Abstract This paper presents an analysis of the recent developments of average market power in Europe by using a broad firm-level database for EU member states. To indicate competitive pressure at the firm-level, markups are estimated following De Loecker, J. (2011). Recovering markups from production data. Int. J. Ind. Organ. 29: 350–355, and De Loecker, J. and Warzynski, F. (2012). Markups and firm-level export status. Am. Econ. Rev. 102: 2437–2471. The analysis reveals a sharp drop in markups during the crisis, followed by a post-crisis increase. The European average has not yet reached its pre-crisis level, which is in contrast to results for the US, where average markups have climbed to pre-crisis levels already in 2011. There is significant heterogeneity among European economies and the pre-crisis levels do have been exceeded in some countries.","PeriodicalId":45967,"journal":{"name":"Jahrbucher Fur Nationalokonomie Und Statistik","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68562473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This work presents novel results obtained by the application of global optimization techniques to the design of finite, normal form games with mixed strategies. To that end, the Fuzzy ASA global optimization method is applied to several design examples of strategic games, demonstrating its effectiveness in obtaining payoff functions whose corresponding games present a previously established Nash equilibrium. In other words, the game designer becomes able to choose a convenient Nash equilibrium for a generic finite state strategic game and the proposed method computes payoff functions that will realize the desired equilibrium, making it possible for the players to reach the favorable conditions represented by the chosen equilibrium. Considering that game theory is a very useful approach for modeling interactions between competing agents and Nash equilibrium represents a powerful solution concept, it is natural to infer that the proposed method may be very useful for strategists in general. In summary, it is a genuine instance of artificial inference of payoff functions after a process of global machine learning, applied to their numerical components.
{"title":"Designing Strategic Games with Preestablished Nash Equilibrium through Artificial Inference and Global Learning","authors":"Hime A. e Oliveira Jr.","doi":"10.1515/jbnst-2020-0040","DOIUrl":"https://doi.org/10.1515/jbnst-2020-0040","url":null,"abstract":"Abstract This work presents novel results obtained by the application of global optimization techniques to the design of finite, normal form games with mixed strategies. To that end, the Fuzzy ASA global optimization method is applied to several design examples of strategic games, demonstrating its effectiveness in obtaining payoff functions whose corresponding games present a previously established Nash equilibrium. In other words, the game designer becomes able to choose a convenient Nash equilibrium for a generic finite state strategic game and the proposed method computes payoff functions that will realize the desired equilibrium, making it possible for the players to reach the favorable conditions represented by the chosen equilibrium. Considering that game theory is a very useful approach for modeling interactions between competing agents and Nash equilibrium represents a powerful solution concept, it is natural to infer that the proposed method may be very useful for strategists in general. In summary, it is a genuine instance of artificial inference of payoff functions after a process of global machine learning, applied to their numerical components.","PeriodicalId":45967,"journal":{"name":"Jahrbucher Fur Nationalokonomie Und Statistik","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/jbnst-2020-0040","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47808241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In order to fight the economic consequences of the COVID-19 pandemic, monetary and fiscal policymakers announced a large variety of support packages which are often unprecedented in size. In this paper, we provide an empirical analysis of the responses of European financial markets to these policy announcements in the spring of 2020. We assemble a granular set of more than 400 policy announcements, both at the national and the European level. We also differentiate between the first announcement in a series of policies and the subsequent announcements because the initial steps were often seen as bad news about the state of the economy. In a panel model, we find that monetary policy, in particular, through asset purchases, is effective in easing the pressure on governmental finances. Stock prices are particularly sensitive to the suspension of the Stability and Growth Pact. Fiscal policy becomes more effective when monetary announcements fall on the same day. We also find sizable cross-border effects of policy announcements.
为了应对COVID-19大流行的经济后果，货币和财政政策制定者宣布了各种各样的支持方案，其规模往往是前所未有的。在本文中，我们对欧洲金融市场对2020年春季这些政策公告的反应进行了实证分析。我们收集了400多项国家和欧洲层面的政策公告。我们还区分了一系列政策中的第一个声明和随后的声明，因为最初的步骤通常被视为有关经济状况的坏消息。在面板模型中，我们发现货币政策，特别是通过资产购买，在缓解政府财政压力方面是有效的。股价对《稳定与增长公约》(Stability and Growth Pact)的中止尤为敏感。当货币政策在同一天宣布时，财政政策会变得更加有效。我们还发现政策公告具有相当大的跨境效应。
{"title":"COVID-19 and Financial Markets: A Panel Analysis for European Countries","authors":"Jens Klose, Peter Tillmann","doi":"10.1515/jbnst-2020-0063","DOIUrl":"https://doi.org/10.1515/jbnst-2020-0063","url":null,"abstract":"Abstract In order to fight the economic consequences of the COVID-19 pandemic, monetary and fiscal policymakers announced a large variety of support packages which are often unprecedented in size. In this paper, we provide an empirical analysis of the responses of European financial markets to these policy announcements in the spring of 2020. We assemble a granular set of more than 400 policy announcements, both at the national and the European level. We also differentiate between the first announcement in a series of policies and the subsequent announcements because the initial steps were often seen as bad news about the state of the economy. In a panel model, we find that monetary policy, in particular, through asset purchases, is effective in easing the pressure on governmental finances. Stock prices are particularly sensitive to the suspension of the Stability and Growth Pact. Fiscal policy becomes more effective when monetary announcements fall on the same day. We also find sizable cross-border effects of policy announcements.","PeriodicalId":45967,"journal":{"name":"Jahrbucher Fur Nationalokonomie Und Statistik","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/jbnst-2020-0063","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66924684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jannes Jacobsen, Magdalena Krieger, Felicitas Schikora, J. Schupp
Abstract This article highlights the potentials for migration research using the German Socio-Economic Panel Study (SOEP), a longitudinal panel dataset of private households in Germany running since 1984. We provide a concise overview of its basic features, describe the survey contents and research potentials, and demonstrate opportunities to link external data sources to the SOEP thereby presenting its diverse and impactful applications in migration research.
{"title":"Growing Potentials for Migration Research using the German Socio-Economic Panel Study","authors":"Jannes Jacobsen, Magdalena Krieger, Felicitas Schikora, J. Schupp","doi":"10.1515/jbnst-2021-0001","DOIUrl":"https://doi.org/10.1515/jbnst-2021-0001","url":null,"abstract":"Abstract This article highlights the potentials for migration research using the German Socio-Economic Panel Study (SOEP), a longitudinal panel dataset of private households in Germany running since 1984. We provide a concise overview of its basic features, describe the survey contents and research potentials, and demonstrate opportunities to link external data sources to the SOEP thereby presenting its diverse and impactful applications in migration research.","PeriodicalId":45967,"journal":{"name":"Jahrbucher Fur Nationalokonomie Und Statistik","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/jbnst-2021-0001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66924416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Aufderheide, Detlef und Martin Dabrowski: Digitalisierung und Künstliche Intelligenz. Wirtschaftsethische und moralökonomische Perspektiven","authors":"Friedhelm Pfeiffer","doi":"10.1515/jbnst-2020-0067","DOIUrl":"https://doi.org/10.1515/jbnst-2020-0067","url":null,"abstract":"","PeriodicalId":45967,"journal":{"name":"Jahrbucher Fur Nationalokonomie Und Statistik","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/jbnst-2020-0067","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66924331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Evaluating environmental questions is a crucial issue in today’s economic research and policy making. The Green-SÖP offers a comprehensive data base to enrich an empirically led scientific discourse as a survey data set on environmental and energy-related topics in Germany. The data set on more than 6000 households was collected by RWI – Leibniz Institute for Economic Research and partners between 2012 and 2016. The questions are very diverse and range from personal attitudes to environmental policy issues with a special focus on the consequences of climate change and individual behaviors as well as opinions on ecologically related matters.
{"title":"Green-SÖP: The Socio-ecological Panel Survey: 2012–2016","authors":"Larissa Klick, G. Kussel, Stephan Sommer","doi":"10.1515/JBNST-2020-0065","DOIUrl":"https://doi.org/10.1515/JBNST-2020-0065","url":null,"abstract":"Abstract Evaluating environmental questions is a crucial issue in today’s economic research and policy making. The Green-SÖP offers a comprehensive data base to enrich an empirically led scientific discourse as a survey data set on environmental and energy-related topics in Germany. The data set on more than 6000 households was collected by RWI – Leibniz Institute for Economic Research and partners between 2012 and 2016. The questions are very diverse and range from personal attitudes to environmental policy issues with a special focus on the consequences of climate change and individual behaviors as well as opinions on ecologically related matters.","PeriodicalId":45967,"journal":{"name":"Jahrbucher Fur Nationalokonomie Und Statistik","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/JBNST-2020-0065","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66924741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This study has two main objectives: first, it assesses the effect of outbreak pandemic diseases on the French firms’ stock returns by considering the sector of activity as the main center of analysis. Second, it investigates the role of the crisis management system, firm debt strategy, and monetary policy in dealing with the adverse shocks of the major outbreak of the COVID-19. The study results can be summarized as follows: (1) the daily growth in COVID-19 cases and deaths are associated with lower stock returns of the listed firms, especially for the firms operating in the energy, industrial and health care sectors. In contrast, telecommunication and consumer sectors are not significantly affected. (2) The pandemic’s adverse effect is much more tolerant with the French firms with an efficient crisis management system and low long-term debt commitments than the firms that do not have such a system and engaged with long term debts. (3) Euribor rates and monetary policy are still playing an essential role during the pandemic period.
{"title":"French Firms and COVID-19: Do the Debt Status, Crisis Management System, and Monetary Policy Play a Role?","authors":"Mina Sami","doi":"10.2139/ssrn.3776603","DOIUrl":"https://doi.org/10.2139/ssrn.3776603","url":null,"abstract":"Abstract This study has two main objectives: first, it assesses the effect of outbreak pandemic diseases on the French firms’ stock returns by considering the sector of activity as the main center of analysis. Second, it investigates the role of the crisis management system, firm debt strategy, and monetary policy in dealing with the adverse shocks of the major outbreak of the COVID-19. The study results can be summarized as follows: (1) the daily growth in COVID-19 cases and deaths are associated with lower stock returns of the listed firms, especially for the firms operating in the energy, industrial and health care sectors. In contrast, telecommunication and consumer sectors are not significantly affected. (2) The pandemic’s adverse effect is much more tolerant with the French firms with an efficient crisis management system and low long-term debt commitments than the firms that do not have such a system and engaged with long term debts. (3) Euribor rates and monetary policy are still playing an essential role during the pandemic period.","PeriodicalId":45967,"journal":{"name":"Jahrbucher Fur Nationalokonomie Und Statistik","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47895542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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