Consumer multi-homing is considered to be critical for competition policy regarding digital platforms. To assess the role of consumer multi-homing in competition policy toward platforms, we develop a new framework that embeds consumer multi-homing in two-sided market into the otherwise standard model of Cournot oligopoly and apply it to free entry and mergers. We find that the equilibrium level of platform entry is insufficient given the presence of consumer multi-homing, and a required level of merger-specific cost reduction is larger if the fraction of multi-homing consumers is larger. These results together provide a caution to the popular belief that multi-homing mitigates the need for a strict implementation of competition policy.
{"title":"Platform Oligopoly with Endogenous Homing: Implications for Free Entry and Mergers","authors":"Takanori Adachi, Susumu Sato, M. Tremblay","doi":"10.2139/ssrn.3937682","DOIUrl":"https://doi.org/10.2139/ssrn.3937682","url":null,"abstract":"Consumer multi-homing is considered to be critical for competition policy regarding digital platforms. To assess the role of consumer multi-homing in competition policy toward platforms, we develop a new framework that embeds consumer multi-homing in two-sided market into the otherwise standard model of Cournot oligopoly and apply it to free entry and mergers. We find that the equilibrium level of platform entry is insufficient given the presence of consumer multi-homing, and a required level of merger-specific cost reduction is larger if the fraction of multi-homing consumers is larger. These results together provide a caution to the popular belief that multi-homing mitigates the need for a strict implementation of competition policy.","PeriodicalId":169574,"journal":{"name":"ERN: Entry & Exit (Topic)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133884591","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}
Biosimilars are close copies of biologic drugs, a group of complex pharmaceutical products that cannot be exactly replicated. The United States Congress passed regulation promoting biosimilar entry in 2010. Since then, the FDA has approved more than 30 biosimilars. We study how the entry of biosimilars has affected price, volume sold, and formulary placement of their corresponding reference biologic drugs. We find that reference biologics react to biosimilar entry much more aggressively than small-molecule brand drugs do to generic entry. We use a simple model to argue that differences in the perceived quality of biosimilar products can explain this discrepancy, and show empirical evidence in support of our theory. The model and empirical results suggest that biosimilars could eventually replace originator biologics, similar to how generic drugs replace brand products, provided that future research confirms the current medical evidence on biosimilars' safety and efficacy.
{"title":"Biosimilar Entry and the Pricing of Biologic Drugs","authors":"Luca Maini, Josh Feng, T. Hwang, Jacob Klimek","doi":"10.2139/ssrn.3760213","DOIUrl":"https://doi.org/10.2139/ssrn.3760213","url":null,"abstract":"Biosimilars are close copies of biologic drugs, a group of complex pharmaceutical products that cannot be exactly replicated. The United States Congress passed regulation promoting biosimilar entry in 2010. Since then, the FDA has approved more than 30 biosimilars. We study how the entry of biosimilars has affected price, volume sold, and formulary placement of their corresponding reference biologic drugs. We find that reference biologics react to biosimilar entry much more aggressively than small-molecule brand drugs do to generic entry. We use a simple model to argue that differences in the perceived quality of biosimilar products can explain this discrepancy, and show empirical evidence in support of our theory. The model and empirical results suggest that biosimilars could eventually replace originator biologics, similar to how generic drugs replace brand products, provided that future research confirms the current medical evidence on biosimilars' safety and efficacy.","PeriodicalId":169574,"journal":{"name":"ERN: Entry & Exit (Topic)","volume":"49 1-2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114118572","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}
Real Justice has nothing in common with redistribution and disgraceful ‘equity’, so we are discussing inequality as a purely economic problem. There are two sources of inequality in focus in this short paper. The first one is rooted in the level of risks accepted by business: if a significant part of entrepreneurs is ‘risk loving’ innovators who could both to lose big or, or to win big it inevitably results in relatively high inequality (as it is observable in the US economy – Acemoglu et al, 2012; Adam Smith). The second source of inequality is high barriers for entering markets protecting crony – capitalists. The latter is quite typical for some autocratic governments as well as for every economy plagued by socialist-like institutions (as a majority of Latin American countries and Israel with 'socially oriented' patron-client pyramids in broad use - De Soto, 2002).
真正的正义与再分配和不体面的“公平”没有任何共同之处，所以我们把不平等作为一个纯粹的经济问题来讨论。在这篇短文中，有两个不平等的来源。第一个是植根于企业所接受的风险水平:如果很大一部分企业家是“热爱风险”的创新者，他们既可能损失惨重，也可能赢得惨重，那么不可避免地会导致相对较高的不平等(正如在美国经济中可以观察到的那样)——Acemoglu等人，2012;亚当•斯密(Adam Smith))。造成不平等的第二个原因是进入市场的高门槛保护了裙带资本家。后者对于一些专制政府以及每一个被类似社会主义制度困扰的经济体(如大多数拉丁美洲国家和以色列广泛使用“面向社会”的赞助人-客户金字塔- De Soto, 2002)来说是非常典型的。
{"title":"Few Notes on Inequality in Israel: The Causes Behind Inequality","authors":"K. Yanovskiy","doi":"10.2139/ssrn.3746659","DOIUrl":"https://doi.org/10.2139/ssrn.3746659","url":null,"abstract":"Real Justice has nothing in common with redistribution and disgraceful ‘equity’, so we are discussing inequality as a purely economic problem. There are two sources of inequality in focus in this short paper. The first one is rooted in the level of risks accepted by business: if a significant part of entrepreneurs is ‘risk loving’ innovators who could both to lose big or, or to win big it inevitably results in relatively high inequality (as it is observable in the US economy – Acemoglu et al, 2012; Adam Smith). The second source of inequality is high barriers for entering markets protecting crony – capitalists. The latter is quite typical for some autocratic governments as well as for every economy plagued by socialist-like institutions (as a majority of Latin American countries and Israel with 'socially oriented' patron-client pyramids in broad use - De Soto, 2002).","PeriodicalId":169574,"journal":{"name":"ERN: Entry & Exit (Topic)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121429298","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}
The competitive strategies of 'gatekeeper' platforms are subject to enhanced scrutiny. For instance, Apple and Google are being accused of charging excessive access fees to app providers and privileging their own apps. Some have argued that such allegations make no economic sense when the platform's business model is to sell devices. In this paper, we build a model in which a gatekeeper device-seller facing potentially saturated demand for its device has the incentive and the ability to exclude from the market third-party suppliers of a service that consumers buy via its devices. Foreclosure is more likely if demand growth for the platform's devices is slow or negative, and can harm consumers if the device-seller's services are inferior to those offered by the third parties.
{"title":"Self-Preferencing in Markets with Vertically-Integrated Gatekeeper Platforms","authors":"Jorge Padilla, J. Perkins, S. Piccolo","doi":"10.2139/ssrn.3701250","DOIUrl":"https://doi.org/10.2139/ssrn.3701250","url":null,"abstract":"The competitive strategies of 'gatekeeper' platforms are subject to enhanced scrutiny. For instance, Apple and Google are being accused of charging excessive access fees to app providers and privileging their own apps. Some have argued that such allegations make no economic sense when the platform's business model is to sell devices. In this paper, we build a model in which a gatekeeper device-seller facing potentially saturated demand for its device has the incentive and the ability to exclude from the market third-party suppliers of a service that consumers buy via its devices. Foreclosure is more likely if demand growth for the platform's devices is slow or negative, and can harm consumers if the device-seller's services are inferior to those offered by the third parties.","PeriodicalId":169574,"journal":{"name":"ERN: Entry & Exit (Topic)","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124511445","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 study the implications of different contractual forms in a market with an incumbent upstream monopolist and free downstream entry. We show that traditional conclusions regarding the desirability of linear contracts radically change when entry in the downstream market is endogenous rather than exogenous. By triggering more entry than two-part tariffs, wholesale price contracts can generate higher aggregate output, consumer surplus, and welfare. In light of this, the upstream monopolist may prefer to trade with wholesale price contracts as well as to give up part of its bargaining power when it is high.
{"title":"Vertical Contracts and Entry","authors":"Chrysovalantou Milliou, E. Petrakis","doi":"10.2139/ssrn.3685117","DOIUrl":"https://doi.org/10.2139/ssrn.3685117","url":null,"abstract":"We study the implications of different contractual forms in a market with an incumbent upstream monopolist and free downstream entry. We show that traditional conclusions regarding the desirability of linear contracts radically change when entry in the downstream market is endogenous rather than exogenous. By triggering more entry than two-part tariffs, wholesale price contracts can generate higher aggregate output, consumer surplus, and welfare. In light of this, the upstream monopolist may prefer to trade with wholesale price contracts as well as to give up part of its bargaining power when it is high.","PeriodicalId":169574,"journal":{"name":"ERN: Entry & Exit (Topic)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132615764","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 present a theory of monopoly protection by means of entry in adjacent markets that have a common customer base (i.e., envelopment). A firm dominant in its market enters a data rich secondary market and engages in predatory pricing and privacy-policy tying. We define the latter as conditioning service provision to the subscription of a privacy-policy that allows bundling of user data across all sources. Acquiring data from the secondary market confers an advantage in the primary market that shields the dominant firm from entry, thus harming consumers. We discuss potential remedies, including data unbundling, sharing and portability.
{"title":"Data-Driven Envelopment with Privacy-Policy Tying","authors":"D. Condorelli, Jorge Padilla","doi":"10.2139/ssrn.3600725","DOIUrl":"https://doi.org/10.2139/ssrn.3600725","url":null,"abstract":"We present a theory of monopoly protection by means of entry in adjacent markets that \u0000have a common customer base (i.e., envelopment). A firm dominant in its market enters a data rich \u0000secondary market and engages in predatory pricing and privacy-policy tying. We define \u0000the latter as conditioning service provision to the subscription of a privacy-policy that allows \u0000bundling of user data across all sources. Acquiring data from the secondary market confers \u0000an advantage in the primary market that shields the dominant firm from entry, thus harming \u0000consumers. We discuss potential remedies, including data unbundling, sharing and portability.","PeriodicalId":169574,"journal":{"name":"ERN: Entry & Exit (Topic)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129637963","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}
Xiaohong Chen, Matthew Gentry, Tong Li, Jingfeng Lu
We study identification and inference in first-price auctions with risk averse bidders and selective entry, building on a flexible entry and bidding framework we call the Affiliated Signal with Risk Aversion (AS-RA) model. Assuming that the econometrician observes either exogenous variation in the number of potential bidders (N) or a continuous instrument (z) shifting opportunity costs of entry, we provide a sharp characterization of the nonparametric restrictions implied by equilibrium bidding. Given variation in either competition or costs, this characterization implies that risk neutrality is nonparametrically testable in the sense that if bidders are strictly risk averse, then no risk neutral model can rationalize the data. In addition, if both instruments (discrete N and continuous z) are available, then the model primitives are nonparametrically point identified. We then explore inference based on these identification results, focusing on set inference and testing when primitives are set identified.
{"title":"Identification and Inference in First-Price Auctions with Risk Averse Bidders and Selective Entry","authors":"Xiaohong Chen, Matthew Gentry, Tong Li, Jingfeng Lu","doi":"10.2139/ssrn.3681530","DOIUrl":"https://doi.org/10.2139/ssrn.3681530","url":null,"abstract":"We study identification and inference in first-price auctions with risk averse bidders and selective entry, building on a flexible entry and bidding framework we call the Affiliated Signal with Risk Aversion (AS-RA) model. Assuming that the econometrician observes either exogenous variation in the number of potential bidders (N) or a continuous instrument (z) shifting opportunity costs of entry, we provide a sharp characterization of the nonparametric restrictions implied by equilibrium bidding. Given variation in either competition or costs, this characterization implies that risk neutrality is nonparametrically testable in the sense that if bidders are strictly risk averse, then no risk neutral model can rationalize the data. In addition, if both instruments (discrete N and continuous z) are available, then the model primitives are nonparametrically point identified. We then explore inference based on these identification results, focusing on set inference and testing when primitives are set identified.","PeriodicalId":169574,"journal":{"name":"ERN: Entry & Exit (Topic)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126915280","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}
One important decision faced by the owners of online marketplaces is whether they should enter the market and sell products directly to customers. In this study, we provide data-driven insights to managers by empirically investigating the impact of a platform owner’s entry on the demand of third-party stores and their potential reactions using transaction level data from a large e-commerce platform. Contrary to previous studies in mobile app platforms, our study shows that the demand of competing third-party stores decreases with the entry of the platform, especially for large third-party stores. We further show that the demand reduction is significant only in the offline channel and the reduction results from third-party stores’ defensive strategy to divert their offline customers away from the platform (i.e., disintermediation). Our findings indicate that platforms should carefully evaluate the nature of their markets before entering the market to compete with complementors, because they may lead third-party sellers to disintermediate from the platform. On the other hand, from the perspective of third-party sellers, disintermediation might be an overreaction to the entry of the platform, because their online demand is not significantly affected by platform entry based on our analyses.
{"title":"Impact of Platform Owner’s Entry on Third-Party Stores","authors":"Shu He, Jing Peng, Jianbin Li, Liping Xu","doi":"10.1287/isre.2020.0957","DOIUrl":"https://doi.org/10.1287/isre.2020.0957","url":null,"abstract":"One important decision faced by the owners of online marketplaces is whether they should enter the market and sell products directly to customers. In this study, we provide data-driven insights to managers by empirically investigating the impact of a platform owner’s entry on the demand of third-party stores and their potential reactions using transaction level data from a large e-commerce platform. Contrary to previous studies in mobile app platforms, our study shows that the demand of competing third-party stores decreases with the entry of the platform, especially for large third-party stores. We further show that the demand reduction is significant only in the offline channel and the reduction results from third-party stores’ defensive strategy to divert their offline customers away from the platform (i.e., disintermediation). Our findings indicate that platforms should carefully evaluate the nature of their markets before entering the market to compete with complementors, because they may lead third-party sellers to disintermediate from the platform. On the other hand, from the perspective of third-party sellers, disintermediation might be an overreaction to the entry of the platform, because their online demand is not significantly affected by platform entry based on our analyses.","PeriodicalId":169574,"journal":{"name":"ERN: Entry & Exit (Topic)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130950297","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}
Using firm level micro-data, I find evidence that firms with lower growth prospects are more sensitive to aggregate shocks. I interpret these findings using a model of demand accumulation and endogenous entry and exit decisions, which I then estimate on French data. The resulting cyclical dynamics of firms provide an explanation for the observed counter-cyclical dispersion in firms' growth rates. They suggest that cyclical dispersion is the result of a pre-existing and persistent characteristic of the firm and caution against its use as a proxy for time-varying uncertainty. The estimated negative correlation between a firm's sensitivity to aggregate shocks and its expected future growth rate is shown to have important consequences for the cyclical characteristics of entering and exiting firms. The quantitative model suggests that this compositional effect is sizeable and equivalent to around 10.5% of the drop in aggregate employment between 2008 and 2009.
{"title":"Aggregate Uncertainty and the Micro-Dynamics of Firms","authors":"Nicolò Dalvit","doi":"10.2139/ssrn.3591987","DOIUrl":"https://doi.org/10.2139/ssrn.3591987","url":null,"abstract":"Using firm level micro-data, I find evidence that firms with lower growth prospects are more sensitive to aggregate shocks. I interpret these findings using a model of demand accumulation and endogenous entry and exit decisions, which I then estimate on French data. The resulting cyclical dynamics of firms provide an explanation for the observed counter-cyclical dispersion in firms' growth rates. They suggest that cyclical dispersion is the result of a pre-existing and persistent characteristic of the firm and caution against its use as a proxy for time-varying uncertainty. The estimated negative correlation between a firm's sensitivity to aggregate shocks and its expected future growth rate is shown to have important consequences for the cyclical characteristics of entering and exiting firms. The quantitative model suggests that this compositional effect is sizeable and equivalent to around 10.5% of the drop in aggregate employment between 2008 and 2009.","PeriodicalId":169574,"journal":{"name":"ERN: Entry & Exit (Topic)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130226403","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}
English Abstract: We study aggregate productivity growth of the Korean manufacturing industry for the 2007-2017 period. We find that the nature of such growth was quite different for two measures of productivity. For labor productivity, most of growth comes from productivity changes among surviving firms. On the other hand, for TFP, most of the productivity growth comes from that of new entrants in recent years. Our work illustrates the different nature of two productivity measures in terms of their growth paths. We also show interesting industry dynamics for both productivity measures, as exiting firms contributed positively to aggregate productivity growth with increasing trends, which suggests that the market had gradually eliminated firms of lower productivity. Using the dynamic Olley and Pakes (1996) decomposition, we also find that for both productivity measures, a substantial productivity growth after the 2008 global financial crisis was due to market share reallocations between firms, but this between-firm contribution has somewhat slowed or been decreasing since then. Our industry sector level study also shows that there has been fundamentally different heterogeneous productivity growth patterns and components across manufacturing sectors.
Finally, we find that the wage level also plays a role in moderating or as an accelerating factor for different productivity growth paths among surviving, entering, and exiting firms. We find that higher wage groups had disproportionately higher entry and exit rates, and that the contributions of these industry dynamics to aggregate productivity growth were largest for the highest wage group while the productivity growth from the between firm component was substantially higher for lower wage groups. Therefore, we find that not only a timely change in input and output, but also in the wage, is a necessary ingredient for the pace and magnitude of reallocation to be effective in aggregate productivity growth.
{"title":"Aggregate Productivity Growth and Firm Dynamics in Korean Manufacturing 2007-2017","authors":"Kyoo il Kim, J. Park","doi":"10.2139/ssrn.3578171","DOIUrl":"https://doi.org/10.2139/ssrn.3578171","url":null,"abstract":"<b>English Abstract:</b> We study aggregate productivity growth of the Korean manufacturing industry for the 2007-2017 period. We find that the nature of such growth was quite different for two measures of productivity. For labor productivity, most of growth comes from productivity changes among surviving firms. On the other hand, for TFP, most of the productivity growth comes from that of new entrants in recent years. Our work illustrates the different nature of two productivity measures in terms of their growth paths. We also show interesting industry dynamics for both productivity measures, as exiting firms contributed positively to aggregate productivity growth with increasing trends, which suggests that the market had gradually eliminated firms of lower productivity. Using the dynamic Olley and Pakes (1996) decomposition, we also find that for both productivity measures, a substantial productivity growth after the 2008 global financial crisis was due to market share reallocations between firms, but this between-firm contribution has somewhat slowed or been decreasing since then. Our industry sector level study also shows that there has been fundamentally different heterogeneous productivity growth patterns and components across manufacturing sectors. <br><br>Finally, we find that the wage level also plays a role in moderating or as an accelerating factor for different productivity growth paths among surviving, entering, and exiting firms. We find that higher wage groups had disproportionately higher entry and exit rates, and that the contributions of these industry dynamics to aggregate productivity growth were largest for the highest wage group while the productivity growth from the between firm component was substantially higher for lower wage groups. Therefore, we find that not only a timely change in input and output, but also in the wage, is a necessary ingredient for the pace and magnitude of reallocation to be effective in aggregate productivity growth.","PeriodicalId":169574,"journal":{"name":"ERN: Entry & Exit (Topic)","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127105802","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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