Pub Date : 2022-09-01Epub Date: 2022-06-10DOI: 10.1016/j.infoecopol.2022.100983
Alexandre Lauri Henriksen, Ana Carolina Zoghbi, Maria Tannuri-Pianto, Rafael Terra
This study analyzes the effect of local Internet speed infrastructure (backhaul) on educational outcomes. In 2008, the Brazilian government implemented an Internet expansion policy that brought broadband to more than 3000 municipalities. The policy was designed with implementation criteria that make it a natural experiment that can be investigated through a regression discontinuity design (RDD). The results suggest worsening proficiency, higher dropout and retention among students from municipalities served by more powerful backhauls, i.e., capable of supporting higher connection speeds over fiberoptic lines. These results are paralleled in the empirical literature, which predominantly indicates negative or neutral effects of Internet access on education. This study demonstrates the need for a deeper reflection on the domestic use of the Internet and its consequences on educational outcomes of school-age children and adolescents.
{"title":"Education outcomes of broadband expansion in Brazilian municipalities","authors":"Alexandre Lauri Henriksen, Ana Carolina Zoghbi, Maria Tannuri-Pianto, Rafael Terra","doi":"10.1016/j.infoecopol.2022.100983","DOIUrl":"10.1016/j.infoecopol.2022.100983","url":null,"abstract":"<div><p>This study analyzes the effect of local Internet speed infrastructure (backhaul) on educational outcomes. In 2008, the Brazilian government implemented an Internet expansion policy that brought broadband to more than 3000 municipalities. The policy was designed with implementation criteria that make it a natural experiment that can be investigated through a regression discontinuity design (RDD). The results suggest worsening proficiency, higher dropout and retention among students from municipalities served by more powerful backhauls, i.e., capable of supporting higher connection speeds over fiberoptic lines. These results are paralleled in the empirical literature, which predominantly indicates negative or neutral effects of Internet access on education. This study demonstrates the need for a deeper reflection on the domestic use of the Internet and its consequences on educational outcomes of school-age children and adolescents.</p></div>","PeriodicalId":47029,"journal":{"name":"Information Economics and Policy","volume":"60 ","pages":"Article 100983"},"PeriodicalIF":2.8,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49592517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01Epub Date: 2022-07-20DOI: 10.1016/j.infoecopol.2022.100991
Irene Bertschek , Reinhold Kesler
Social media open up new possibilities for firms to exploit information from various external sources. Does this information help firms to become more innovative? Combining firm-level survey data with information from firms’ Facebook pages, we study the role that firms’ and users’ activities on Facebook play in the innovation process. We find that firms’ adoption of a Facebook page as well as feedback from users are positively and significantly related to product innovations. Our results withstand a large set of robustness checks, including estimations that take potential endogeneity of firms’ Facebook use as well as unobserved heterogeneity into account. Analyzing the content of firm posts and user comments reveals that Facebook adoption is only correlated with product innovations if firms and users actively participate in a discussion, especially when engagement is above-average and comes from both sides.
{"title":"Let the user speak: Is feedback on Facebook a source of firms’ innovation?","authors":"Irene Bertschek , Reinhold Kesler","doi":"10.1016/j.infoecopol.2022.100991","DOIUrl":"https://doi.org/10.1016/j.infoecopol.2022.100991","url":null,"abstract":"<div><p>Social media open up new possibilities for firms to exploit information from various external sources. Does this information help firms to become more innovative? Combining firm-level survey data with information from firms’ Facebook pages, we study the role that firms’ and users’ activities on Facebook play in the innovation process. We find that firms’ adoption of a Facebook page as well as feedback from users are positively and significantly related to product innovations. Our results withstand a large set of robustness checks, including estimations that take potential endogeneity of firms’ Facebook use as well as unobserved heterogeneity into account. Analyzing the content of firm posts and user comments reveals that Facebook adoption is only correlated with product innovations if firms and users actively participate in a discussion, especially when engagement is above-average and comes from both sides.</p></div>","PeriodicalId":47029,"journal":{"name":"Information Economics and Policy","volume":"60 ","pages":"Article 100991"},"PeriodicalIF":2.8,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137419572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01Epub Date: 2022-06-14DOI: 10.1016/j.infoecopol.2022.100984
Daniel Garcia
This paper studies third-degree price discrimination in a classical model of price competition with differentiated products. Firms charge different prices to different consumers, based on their estimate of their price sensitivity. If the market is fully covered and information is symmetric, more accurate information has a pure redistributive effect, leading to higher profits but lower consumer welfare. If the market is not covered, information always benefit firms but the welfare effects are ambiguous. If information is asymmetric, firms benefit from more information, but less so than in the symmetric case, and total welfare depends on the extent of this asymmetry. I conclude that firms have strong incentives to share information about consumer tastes.
{"title":"Harmonic price targeting","authors":"Daniel Garcia","doi":"10.1016/j.infoecopol.2022.100984","DOIUrl":"10.1016/j.infoecopol.2022.100984","url":null,"abstract":"<div><p>This paper studies third-degree price discrimination in a classical model of price competition with differentiated products. Firms charge different prices to different consumers, based on their estimate of their price sensitivity. If the market is fully covered and information is symmetric, more accurate information has a pure redistributive effect, leading to higher profits but lower consumer welfare. If the market is not covered, information always benefit firms but the welfare effects are ambiguous. If information is asymmetric, firms benefit from more information, but less so than in the symmetric case, and total welfare depends on the extent of this asymmetry. I conclude that firms have strong incentives to share information about consumer tastes.</p></div>","PeriodicalId":47029,"journal":{"name":"Information Economics and Policy","volume":"60 ","pages":"Article 100984"},"PeriodicalIF":2.8,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0167624522000233/pdfft?md5=8955d3b3c4aacb7846a5a2e7220c9647&pid=1-s2.0-S0167624522000233-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43703497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01Epub Date: 2022-07-19DOI: 10.1016/j.infoecopol.2022.100990
João Martins , Linda Gonçalves Veiga
Administrative and regulatory burden reduction is critical to improving government efficiency and economic competitiveness. Innovations in government through Information and Communication Technologies are key tools in designing policies to achieve these goals. Using a panel dataset covering 169 countries from 2004 to 2018, we investigate the possible contribution of digital government as a business facilitator. The empirical results suggest that progress in digital government contributes to reducing administrative and regulatory burdens, creating a more business-friendly environment in several areas of business regulations. Governance effectiveness may also play a significant role in facilitating business. The results are robust to a battery of robustness tests and alternative empirical strategies.
{"title":"Digital government as a business facilitator","authors":"João Martins , Linda Gonçalves Veiga","doi":"10.1016/j.infoecopol.2022.100990","DOIUrl":"10.1016/j.infoecopol.2022.100990","url":null,"abstract":"<div><p>Administrative and regulatory burden reduction is critical to improving government efficiency and economic competitiveness. Innovations in government through Information and Communication Technologies are key tools in designing policies to achieve these goals. Using a panel dataset covering 169 countries from 2004 to 2018, we investigate the possible contribution of digital government as a business facilitator. The empirical results suggest that progress in digital government contributes to reducing administrative and regulatory burdens, creating a more business-friendly environment in several areas of business regulations. Governance effectiveness may also play a significant role in facilitating business. The results are robust to a battery of robustness tests and alternative empirical strategies.</p></div>","PeriodicalId":47029,"journal":{"name":"Information Economics and Policy","volume":"60 ","pages":"Article 100990"},"PeriodicalIF":2.8,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0167624522000294/pdfft?md5=71149ee0f13d67abe805226bbcc6fe50&pid=1-s2.0-S0167624522000294-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43002730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01Epub Date: 2022-06-29DOI: 10.1016/j.infoecopol.2022.100988
Laura Abrardi, Carlo Cambini
In this paper, we study the optimal design of incentives to induce a digital platform to limit the extraction of data from users, whose privacy loss is further aggravated by their naive use of the platform. We show that caps on the amount of data collected can induce the optimal data-saving effort by the platform. If the platform’s effort is not observable, a menu of data caps should be provided and it entails a higher (lower) loss of privacy for less (more) naive users, relative to the first best. We also show that compensating users for their data can efficiently incentivize effort, but might increase the privacy loss of more naive users.
{"title":"Carpe Data: Protecting online privacy with naive users","authors":"Laura Abrardi, Carlo Cambini","doi":"10.1016/j.infoecopol.2022.100988","DOIUrl":"10.1016/j.infoecopol.2022.100988","url":null,"abstract":"<div><p>In this paper, we study the optimal design of incentives to induce a digital platform to limit the extraction of data from users, whose privacy loss is further aggravated by their naive use of the platform. We show that caps on the amount of data collected can induce the optimal data-saving effort by the platform. If the platform’s effort is not observable, a menu of data caps should be provided and it entails a higher (lower) loss of privacy for less (more) naive users, relative to the first best. We also show that compensating users for their data can efficiently incentivize effort, but might increase the privacy loss of more naive users.</p></div>","PeriodicalId":47029,"journal":{"name":"Information Economics and Policy","volume":"60 ","pages":"Article 100988"},"PeriodicalIF":2.8,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43801499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01Epub Date: 2022-07-22DOI: 10.1016/j.infoecopol.2022.100989
Alexander Cuntz , Kyle Bergquist
Platforms often compete over non-price strategies such as the exclusive distribution of products. But these strategies are not always welfare-enhancing. Using rich data on audiovisuals distributed on platforms in Brazil, we find that non-exclusive distribution and availability of titles across platforms is more effective in deterring online piracy than in the single-homing case. Moreover, for the subset of domestic movies, it induces higher average investment in the quality of new titles upstream. We discuss options of copyright and competition policies in the light of these findings.
{"title":"Exclusive content and platform competition in Latin America","authors":"Alexander Cuntz , Kyle Bergquist","doi":"10.1016/j.infoecopol.2022.100989","DOIUrl":"10.1016/j.infoecopol.2022.100989","url":null,"abstract":"<div><p>Platforms often compete over non-price strategies such as the exclusive distribution of products. But these strategies are not always welfare-enhancing. Using rich data on audiovisuals distributed on platforms in Brazil, we find that non-exclusive distribution and availability of titles across platforms is more effective in deterring online piracy than in the single-homing case. Moreover, for the subset of domestic movies, it induces higher average investment in the quality of new titles upstream. We discuss options of copyright and competition policies in the light of these findings.</p></div>","PeriodicalId":47029,"journal":{"name":"Information Economics and Policy","volume":"60 ","pages":"Article 100989"},"PeriodicalIF":2.8,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45815665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01Epub Date: 2022-08-08DOI: 10.1016/j.infoecopol.2022.100994
Elmar G. Wolfstetter
Millions of citizens and firms lack access to high speed internet, even though governments pledged to spend huge sums of money to subsidize internet networks. In this paper we review some systematic flaws of present policies and outline a promising alternative. We propose that governments should treat the broadband infrastructure as a public responsibility and set up public-private partnerships that deploy, fund, and temporarily operate the broadband in exchange for collecting service fees and, if necessary, subsidies. Least-present-value-of-revenue auctions can be used to award all concessions, not only those that are expected to require subsidies, and concessions should revert to public ownership and be re-auctioned if the promised present value of revenue has been reached through collection of service fees. This procurement method is easy to implement, efficient, and immune to strategic manipulations and renegotiations.
{"title":"Universal high-speed broadband provision: A simple auction approach","authors":"Elmar G. Wolfstetter","doi":"10.1016/j.infoecopol.2022.100994","DOIUrl":"10.1016/j.infoecopol.2022.100994","url":null,"abstract":"<div><p>Millions of citizens and firms lack access to high speed internet, even though governments pledged to spend huge sums of money to subsidize internet networks. In this paper we review some systematic flaws of present policies and outline a promising alternative. We propose that governments should treat the broadband infrastructure as a public responsibility and set up public-private partnerships that deploy, fund, and temporarily operate the broadband in exchange for collecting service fees and, if necessary, subsidies. Least-present-value-of-revenue auctions can be used to award all concessions, not only those that are expected to require subsidies, and concessions should revert to public ownership and be re-auctioned if the promised present value of revenue has been reached through collection of service fees. This procurement method is easy to implement, efficient, and immune to strategic manipulations and renegotiations.</p></div>","PeriodicalId":47029,"journal":{"name":"Information Economics and Policy","volume":"60 ","pages":"Article 100994"},"PeriodicalIF":2.8,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48970249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We study the competitive effects of a vertical merger in a digital industry where an integrated incumbent (closed ecosystem) competes with an open ecosystem formed by an upstream supplier (ecosystem gatekeeper) and two downstream retailers selling differentiated products. Absent innovation, the incumbent sells a superior product compared to the rivals’ ones. Yet, the gatekeeper of the open ecosystem can fill up this gap by engaging in product innovation. We investigate the impact of vertical integration on the gatekeeper’s incentives to foreclose its non-integrated downstream unit and innovate its ecosystem to compete head-to-head with the incumbent. The vertically integrated gatekeeper raises the costs of the unintegrated competitor to relax intra-ecosystem competition but does not fully foreclose it as that would cause fiercer inter-ecosystem competition. Moreover, vertical integration enhances innovation within the open ecosystem, enabling its participants to catch up with the incumbent. Overall, vertical integration may benefit consumers even when it softens intra-ecosystem competition.
{"title":"Vertical integration, innovation and foreclosure with competing ecosystems","authors":"Michele Bisceglia , Jorge Padilla , Salvatore Piccolo , Shiva Shekhar","doi":"10.1016/j.infoecopol.2022.100981","DOIUrl":"https://doi.org/10.1016/j.infoecopol.2022.100981","url":null,"abstract":"<div><p>We study the competitive effects of a vertical merger in a digital industry where an integrated incumbent (closed ecosystem) competes with an open ecosystem formed by an upstream supplier (ecosystem gatekeeper) and two downstream retailers selling differentiated products. Absent innovation, the incumbent sells a superior product compared to the rivals’ ones. Yet, the gatekeeper of the open ecosystem can fill up this gap by engaging in product innovation. We investigate the impact of vertical integration on the gatekeeper’s incentives to foreclose its non-integrated downstream unit and innovate its ecosystem to compete head-to-head with the incumbent. The vertically integrated gatekeeper raises the costs of the unintegrated competitor to relax intra-ecosystem competition but does not fully foreclose it as that would cause fiercer inter-ecosystem competition. Moreover, vertical integration enhances innovation within the open ecosystem, enabling its participants to catch up with the incumbent. Overall, vertical integration may benefit consumers even when it softens intra-ecosystem competition.</p></div>","PeriodicalId":47029,"journal":{"name":"Information Economics and Policy","volume":"60 ","pages":"Article 100981"},"PeriodicalIF":2.8,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137419574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development of online social media has raised concerns about how individuals are over-exposed to partisan news. However, social media are only a part of the daily media diet of an average consumer (Allcott and Gentzkow, 2017; Allen et al., 2020). The aim of this paper is therefore to examine partisan news exposure with respect to the entire media diet. We develop a partisan selective exposure index that indicates the over-representation of partisan political opinions in individual daily news consumption. Our analysis of data from a survey of 4,000 people in France shows that on average, partisan exposure is low when social media are excluded. Our estimations also indicate that social media consumption increases selective exposure to partisan content. While the youngest and the less educated appear to be less exposed to partisan content in the absence of social media, our results suggest that this is no longer the case when social media are included in the news diet. Finally, we show that the more people declare extreme (right- or left-wing) political views, the more they are over-exposed to like-minded content.
在线社交媒体的发展引发了人们对个人如何过度接触党派新闻的担忧。然而,社交媒体只是普通消费者日常媒体饮食的一部分(Allcott and Gentzkow, 2017;Allen et al., 2020)。因此,本文的目的是研究党派新闻曝光与整个媒体饮食。我们开发了一个党派选择性曝光指数,表明党派政治观点在个人日常新闻消费中的过度代表。我们对法国4000人的调查数据进行了分析,结果显示,在排除社交媒体的情况下,党派曝光率平均较低。我们的估计还表明,社交媒体消费增加了对党派内容的选择性曝光。虽然在没有社交媒体的情况下,最年轻和受教育程度较低的人似乎较少接触到党派内容,但我们的研究结果表明,当社交媒体被纳入新闻饮食时,情况就不再如此了。最后,我们表明,越多的人表达极端(右翼或左翼)的政治观点,他们就越容易接触到志同道合的内容。
{"title":"Partisan selective exposure in news consumption","authors":"Sylvain Dejean , Marianne Lumeau , Stéphanie Peltier","doi":"10.1016/j.infoecopol.2022.100992","DOIUrl":"10.1016/j.infoecopol.2022.100992","url":null,"abstract":"<div><p>The development of online social media has raised concerns about how individuals are over-exposed to partisan news. However, social media are only a part of the daily media diet of an average consumer (<span>Allcott and Gentzkow, 2017</span>; <span>Allen et al., 2020</span>). The aim of this paper is therefore to examine partisan news exposure with respect to the entire media diet. We develop a partisan selective exposure index that indicates the over-representation of partisan political opinions in individual daily news consumption. Our analysis of data from a survey of 4,000 people in France shows that on average, partisan exposure is low when social media are excluded. Our estimations also indicate that social media consumption increases selective exposure to partisan content. While the youngest and the less educated appear to be less exposed to partisan content in the absence of social media, our results suggest that this is no longer the case when social media are included in the news diet. Finally, we show that the more people declare extreme (right- or left-wing) political views, the more they are over-exposed to like-minded content.</p></div>","PeriodicalId":47029,"journal":{"name":"Information Economics and Policy","volume":"60 ","pages":"Article 100992"},"PeriodicalIF":2.8,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48185812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01Epub Date: 2022-06-23DOI: 10.1016/j.infoecopol.2022.100982
Guilherme Amorim , Rafael Costa Lima , Breno Sampaio
This paper investigates the influence of broadband internet availability in the occurrence of events of civil unrest. Using collected data on 2011’s Occupy Movement in the U.S., we find that each new Internet Service Provider (which is associated to an increase in broadband penetration) accounts for an increase between 1 and 3 p.p. in the probability of observing protests in a given location. Results are consistent when analyzing county-level data for the contiguous U.S., for each different U.S. region separately (Northeast, Midwest, South and West), and when analyzing city-level data for California.
{"title":"Broadband internet and protests: Evidence from the Occupy movement","authors":"Guilherme Amorim , Rafael Costa Lima , Breno Sampaio","doi":"10.1016/j.infoecopol.2022.100982","DOIUrl":"https://doi.org/10.1016/j.infoecopol.2022.100982","url":null,"abstract":"<div><p>This paper investigates the influence of broadband internet availability in the occurrence of events of civil unrest. Using collected data on 2011’s Occupy Movement in the U.S., we find that each new Internet Service Provider (which is associated to an increase in broadband penetration) accounts for an increase between 1 and 3 p.p. in the probability of observing protests in a given location. Results are consistent when analyzing county-level data for the contiguous U.S., for each different U.S. region separately (Northeast, Midwest, South and West), and when analyzing city-level data for California.</p></div>","PeriodicalId":47029,"journal":{"name":"Information Economics and Policy","volume":"60 ","pages":"Article 100982"},"PeriodicalIF":2.8,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137419573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}