We propose an adjustment in mean-variance portfolio weights to incorporate uncertainty caused by the fact that, in general, we have to use estimated expected returns.The adjustment amounts to using a higher pseudo risk-aversion rather than the actual risk-aversion.The difference between the actual and the pseudo risk-aversion depends on the sample size, the number of assets in the portfolio, and the curvature of the mean-variance frontier.Applying the adjustment to international portfolios, we show that the adjustments are nontrivial for G5 country portfolios and that they are even more important when emerging markets are included.We also show that, in the case of time-varying expected country returns, our adjustment implies a signifficantly smaller variability in portfolio weights than is commonly believed.
{"title":"Incorporating Estimation Risk in Portfolio Choice","authors":"J. ter Horst, Frans de Roon, B. Werker","doi":"10.2139/ssrn.244695","DOIUrl":"https://doi.org/10.2139/ssrn.244695","url":null,"abstract":"We propose an adjustment in mean-variance portfolio weights to incorporate uncertainty caused by the fact that, in general, we have to use estimated expected returns.The adjustment amounts to using a higher pseudo risk-aversion rather than the actual risk-aversion.The difference between the actual and the pseudo risk-aversion depends on the sample size, the number of assets in the portfolio, and the curvature of the mean-variance frontier.Applying the adjustment to international portfolios, we show that the adjustments are nontrivial for G5 country portfolios and that they are even more important when emerging markets are included.We also show that, in the case of time-varying expected country returns, our adjustment implies a signifficantly smaller variability in portfolio weights than is commonly believed.","PeriodicalId":126917,"journal":{"name":"European Financial Management Association Meetings (EFMA) (Archive)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116776890","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 analyzes qualitatively the impact of changes in the level and variability of the US dollar/EURO exchange rate on the real GDP growth rate and trade balance positions of three MENA countries, namely Egypt, Jordan and Morocco. First, the analytical framework is presented by developing explicit relationships between (1) output growth and the variability of the nominal exchange rate; (2) per capita GDP and the variability and realignment of the real exchange rate; and (3) commodity prices and nominal exchange rate volatility. Then, based on these models, the impacts of (1) an appreciation of the US dollar against the EURO and (2) an increase in the volatility of the US dollar/EURO rate are derived. Our results indicate that an appreciation of the US dollar/EURO rate or an increase in the volatility of this rate leads to a lower real GDP growth rate and worsening of the trade balance positions for Egypt and Jordan, that effectively peg their currencies to the US dollar, and the opposite for Morocco, that effectively pegs its currency to the EURO. In contrast, an appreciation of the EURO against the US dollar encourages imports to and discourages exports from the EMU region to countries that peg their currencies to the US dollar. This appreciation, however, tends to lower inflation in countries with EURO-denominated products, partly because of lower costs for the imported components. In general, a EURO appreciation results in higher economic activity growth of countries that have US dollar-denominated products, and puts competitiveness pressures on countries that have EURO-denominated products.
{"title":"Assessing the Impact of the Euro on the Economies of Some MENA Countries: An Empirical Investigation Utilizing a Time-Varying Model to Forecast the Level and Volatility of the Us Dollar/Euro Exchange Rate","authors":"A. Abutaleb, Michael G. Papaioannou","doi":"10.2139/ssrn.314824","DOIUrl":"https://doi.org/10.2139/ssrn.314824","url":null,"abstract":"This paper analyzes qualitatively the impact of changes in the level and variability of the US dollar/EURO exchange rate on the real GDP growth rate and trade balance positions of three MENA countries, namely Egypt, Jordan and Morocco. First, the analytical framework is presented by developing explicit relationships between (1) output growth and the variability of the nominal exchange rate; (2) per capita GDP and the variability and realignment of the real exchange rate; and (3) commodity prices and nominal exchange rate volatility. Then, based on these models, the impacts of (1) an appreciation of the US dollar against the EURO and (2) an increase in the volatility of the US dollar/EURO rate are derived. Our results indicate that an appreciation of the US dollar/EURO rate or an increase in the volatility of this rate leads to a lower real GDP growth rate and worsening of the trade balance positions for Egypt and Jordan, that effectively peg their currencies to the US dollar, and the opposite for Morocco, that effectively pegs its currency to the EURO. In contrast, an appreciation of the EURO against the US dollar encourages imports to and discourages exports from the EMU region to countries that peg their currencies to the US dollar. This appreciation, however, tends to lower inflation in countries with EURO-denominated products, partly because of lower costs for the imported components. In general, a EURO appreciation results in higher economic activity growth of countries that have US dollar-denominated products, and puts competitiveness pressures on countries that have EURO-denominated products.","PeriodicalId":126917,"journal":{"name":"European Financial Management Association Meetings (EFMA) (Archive)","volume":"128 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132424892","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 this paper we investigate the performance of European bond funds which, as far as we are aware of, have not yet been studied. Both unconditional and conditional models are used to evaluate fund performance. As conditioning information we use variables that we find to be useful in predicting bond market returns in the European Market. We also test the sensitivity of bond fund performance to single and multiple benchmarks. The results show that, in general, bond funds are not able to outperform passive strategies. The negative performance is more evident for bond funds in Italy, Spain, Portugal and also for UK "Gilt" funds. For most German funds and UK "Corporate" and "Other Bond" funds and also for several French funds we cannot reject the hypothesis of neutral performance. These findings are robust to whatever model (unconditional versus conditional and single versus multi-index) we use. In general, the multi-index model seems to add some explanatory power in relation to the single-index model. Furthermore, when we incorporate the predetermined information variables, we can observe a slight tendency towards better performance, in particular for the multi-index model. This evidence is consistent with previous studies on stock funds and comes in support of the argument that conditional models might allow for a better assessment of performance. However, our results suggest that the impact of additional risk factors seems to be greater than the impact of incorporating predetermined information variables.
{"title":"Conditioning Information and European Bond Fund Performance","authors":"F. Silva, M. C. Cortez","doi":"10.2139/ssrn.300539","DOIUrl":"https://doi.org/10.2139/ssrn.300539","url":null,"abstract":"In this paper we investigate the performance of European bond funds which, as far as we are aware of, have not yet been studied. Both unconditional and conditional models are used to evaluate fund performance. As conditioning information we use variables that we find to be useful in predicting bond market returns in the European Market. We also test the sensitivity of bond fund performance to single and multiple benchmarks. The results show that, in general, bond funds are not able to outperform passive strategies. The negative performance is more evident for bond funds in Italy, Spain, Portugal and also for UK \"Gilt\" funds. For most German funds and UK \"Corporate\" and \"Other Bond\" funds and also for several French funds we cannot reject the hypothesis of neutral performance. These findings are robust to whatever model (unconditional versus conditional and single versus multi-index) we use. In general, the multi-index model seems to add some explanatory power in relation to the single-index model. Furthermore, when we incorporate the predetermined information variables, we can observe a slight tendency towards better performance, in particular for the multi-index model. This evidence is consistent with previous studies on stock funds and comes in support of the argument that conditional models might allow for a better assessment of performance. However, our results suggest that the impact of additional risk factors seems to be greater than the impact of incorporating predetermined information variables.","PeriodicalId":126917,"journal":{"name":"European Financial Management Association Meetings (EFMA) (Archive)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123818312","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}
Building upon the seminal work of Easley, Kiefer, O'Hara and Paperman (1996), we develop a framework to investigate the relationship between the behavior of uninformed investors and the time-varying informed trading activities. We allow the arrival rates for uninformed traders to follow a Markov switching process where the transition probabilities depend on market fundamentals. Informed traders may match the level of the uninformed arrival rate with certain probability so as to make better use of the camouflage provided by the uninformed transactions. Our empirical estimation of NYSE stocks shows that the uninformed transition probabilities are indeed time-varying, so is the probability of information content. The estimated probability of information content predicts the opening, median and closing spreads. There is evidence that uninformed investors exhibit momentum chasing and "noise herding" behavior. There is also a positive "market spillover" effect in the uninformed trading activities. We find that the "clustering" of trading activities by uninformed and informed traders seem to be more likely on low volume days, and the uninformed trading activities are responsible for most of the stock trading volatilities.
{"title":"The Behavior of Uninformed Investors and Time-Varying Informed Trading Activities","authors":"Qin Lei, Guojun Wu","doi":"10.2139/ssrn.289690","DOIUrl":"https://doi.org/10.2139/ssrn.289690","url":null,"abstract":"Building upon the seminal work of Easley, Kiefer, O'Hara and Paperman (1996), we develop a framework to investigate the relationship between the behavior of uninformed investors and the time-varying informed trading activities. We allow the arrival rates for uninformed traders to follow a Markov switching process where the transition probabilities depend on market fundamentals. Informed traders may match the level of the uninformed arrival rate with certain probability so as to make better use of the camouflage provided by the uninformed transactions. Our empirical estimation of NYSE stocks shows that the uninformed transition probabilities are indeed time-varying, so is the probability of information content. The estimated probability of information content predicts the opening, median and closing spreads. There is evidence that uninformed investors exhibit momentum chasing and \"noise herding\" behavior. There is also a positive \"market spillover\" effect in the uninformed trading activities. We find that the \"clustering\" of trading activities by uninformed and informed traders seem to be more likely on low volume days, and the uninformed trading activities are responsible for most of the stock trading volatilities.","PeriodicalId":126917,"journal":{"name":"European Financial Management Association Meetings (EFMA) (Archive)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123433852","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 of the interesting findings among the seasonalities in stock markets is that the return, volume and volatility of the stock prices and bid-ask spreads all broadly follow a U-shaped pattern over the trading day. This study examines the intra-daily seasonalities of the stock returns in the emerging Turkish Stock Market which is an order-driven continuous auction market using electronic trading without market makers in the period from January 1, 1996 through January 15, 1999 by using 15-minute (and also 5 minute and 1 minute) interval data. Results show that stock returns follow a U-shaped or more precisely a W-shaped pattern over the trading day at the Istanbul Stock Exchange (ISE) since there are two trading sessions in a day. This result is consistent with the previous findings in the literature. Opening (Overnight) and closing returns are significantly large and positive. In addition, volatility is higher at the openings and follows an L-shape pattern during the both sessions. Interestingly, the daily average close-to-close returns are generated only during the opening and closing intervals and the average intra-day return is negative when the returns at the opening and/or closing intervals (even the first and the last minutes of the day) are excluded from the analyses. Thus, the rest of the trading day provides no gains (losses) to close-to-close overall returns. Findings suggest that relatively higher closing prices are not corrected by the market at the opening of the next trading day. Relatively higher mean return and standard deviation at the openings of the trading sessions seem to be significantly generated by the accumulated overnight information and the closed-market effect (halt of trade). Mondays have the highest opening mean return and volatility among the days of the week supports this explanation. On the other hand, large day-end returns are strongly affected by the activities of fund managers and speculators who, at the end of the day, boost their portfolios' asset value by bidding higher and accepting ask prices that result to higher closing prices with the contribution of relatively higher minimum tick sizes determined by the Stock Exchange. Intra-day seasonalities that also exist significantly in the Turkish Stock Market, are consistent with those of the international stock markets. This conclusion implies that large profits can be realized by using a simple trading rule, based on the strong intra-day seasonalities in stock returns at the ISE, such as buying and selling stocks at a particular time of the day.
{"title":"Intra-Day Seasonalities on Stock Returns: Evidence from the Turkish Stock Market","authors":"Recep Bildik","doi":"10.2139/ssrn.251503","DOIUrl":"https://doi.org/10.2139/ssrn.251503","url":null,"abstract":"One of the interesting findings among the seasonalities in stock markets is that the return, volume and volatility of the stock prices and bid-ask spreads all broadly follow a U-shaped pattern over the trading day. This study examines the intra-daily seasonalities of the stock returns in the emerging Turkish Stock Market which is an order-driven continuous auction market using electronic trading without market makers in the period from January 1, 1996 through January 15, 1999 by using 15-minute (and also 5 minute and 1 minute) interval data. Results show that stock returns follow a U-shaped or more precisely a W-shaped pattern over the trading day at the Istanbul Stock Exchange (ISE) since there are two trading sessions in a day. This result is consistent with the previous findings in the literature. Opening (Overnight) and closing returns are significantly large and positive. In addition, volatility is higher at the openings and follows an L-shape pattern during the both sessions. Interestingly, the daily average close-to-close returns are generated only during the opening and closing intervals and the average intra-day return is negative when the returns at the opening and/or closing intervals (even the first and the last minutes of the day) are excluded from the analyses. Thus, the rest of the trading day provides no gains (losses) to close-to-close overall returns. Findings suggest that relatively higher closing prices are not corrected by the market at the opening of the next trading day. Relatively higher mean return and standard deviation at the openings of the trading sessions seem to be significantly generated by the accumulated overnight information and the closed-market effect (halt of trade). Mondays have the highest opening mean return and volatility among the days of the week supports this explanation. On the other hand, large day-end returns are strongly affected by the activities of fund managers and speculators who, at the end of the day, boost their portfolios' asset value by bidding higher and accepting ask prices that result to higher closing prices with the contribution of relatively higher minimum tick sizes determined by the Stock Exchange. Intra-day seasonalities that also exist significantly in the Turkish Stock Market, are consistent with those of the international stock markets. This conclusion implies that large profits can be realized by using a simple trading rule, based on the strong intra-day seasonalities in stock returns at the ISE, such as buying and selling stocks at a particular time of the day.","PeriodicalId":126917,"journal":{"name":"European Financial Management Association Meetings (EFMA) (Archive)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130874011","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 explores whether speculative activity can,in practice,generate the ARCH- type behavior found in .nancial time series.Specifically,G7 equity marke indices are examined for evidence of a dynamic whereby speculative interest is self-sustaining, that is,markets can become 'hot'. A straightforward model,taken from Faruqee and Redding [9 ],generates some testable implications of the idea.Tests of the model on the data show that not only does he model offer an explanation for volatility clustering,but also can be considered a statistical improvement on standard GARCH representations.
{"title":"Arch in the G7 Equity Markets: A Speculative Explanation","authors":"Lee Redding","doi":"10.2139/ssrn.314864","DOIUrl":"https://doi.org/10.2139/ssrn.314864","url":null,"abstract":"This paper explores whether speculative activity can,in practice,generate the ARCH- type behavior found in .nancial time series.Specifically,G7 equity marke indices are examined for evidence of a dynamic whereby speculative interest is self-sustaining, that is,markets can become 'hot'. A straightforward model,taken from Faruqee and Redding [9 ],generates some testable implications of the idea.Tests of the model on the data show that not only does he model offer an explanation for volatility clustering,but also can be considered a statistical improvement on standard GARCH representations.","PeriodicalId":126917,"journal":{"name":"European Financial Management Association Meetings (EFMA) (Archive)","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123588322","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}
Pub Date : 2001-11-01DOI: 10.1016/B978-075065332-9.50011-2
A. Tsekrekos
{"title":"The Effect of First-Mover's Advantages on the Strategic Exercise of Real Options","authors":"A. Tsekrekos","doi":"10.1016/B978-075065332-9.50011-2","DOIUrl":"https://doi.org/10.1016/B978-075065332-9.50011-2","url":null,"abstract":"","PeriodicalId":126917,"journal":{"name":"European Financial Management Association Meetings (EFMA) (Archive)","volume":"143 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133639383","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 analyzes the ex-dividend day stock price behavior in the Athens Stock Exchange (ASE) over the period 1994-1999. This market is chosen because neither dividends nor capital gains are taxed and the ASE is not associated with the microstructure effects analyzed in prior studies. Our findings show that on the ex-dividend day, stock prices fall by less than the dividend paid. These findings cannot be attributed to tax effects. Although our evidence might be attributed to microstructure effects, we argue that the particular microstructure effects identified by prior studies may not be the determinant factors.
{"title":"The Ex-Dividend Day Stock Price Behavior in the Athens Stock Exchange","authors":"N. Travlos, Nikolaos T. Milonas","doi":"10.2139/ssrn.274080","DOIUrl":"https://doi.org/10.2139/ssrn.274080","url":null,"abstract":"This paper analyzes the ex-dividend day stock price behavior in the Athens Stock Exchange (ASE) over the period 1994-1999. This market is chosen because neither dividends nor capital gains are taxed and the ASE is not associated with the microstructure effects analyzed in prior studies. Our findings show that on the ex-dividend day, stock prices fall by less than the dividend paid. These findings cannot be attributed to tax effects. Although our evidence might be attributed to microstructure effects, we argue that the particular microstructure effects identified by prior studies may not be the determinant factors.","PeriodicalId":126917,"journal":{"name":"European Financial Management Association Meetings (EFMA) (Archive)","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114032534","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}
There is a gap between the theoretical literature which almost unanimously advo-cates privatisation of enterprises, as a part of the solution for the commitment prob-lem in economies in transition, and empirical evidence on how best to design a pri-vatisation programme in order to secure an efficient use of resources. This paper contributes to this debate by focusing on the determinants of financial performance of privatised firms in Poland, Hungary, and the Czech Republic. Our results suggest positive long-term returns for foreign investors in newly privatised companies. The returns are particularly high and statistically significant for investors in Polish com-panies. The long-term performance is influenced by firms? size, retained state own-ership, and the choice of a privatisation method.
{"title":"The Financial Performance of Privatised Firms: Evidence from Three Transition Economies","authors":"R. Jelic, R. Briston, Wolfgang Aussenegg","doi":"10.2139/ssrn.273875","DOIUrl":"https://doi.org/10.2139/ssrn.273875","url":null,"abstract":"There is a gap between the theoretical literature which almost unanimously advo-cates privatisation of enterprises, as a part of the solution for the commitment prob-lem in economies in transition, and empirical evidence on how best to design a pri-vatisation programme in order to secure an efficient use of resources. This paper contributes to this debate by focusing on the determinants of financial performance of privatised firms in Poland, Hungary, and the Czech Republic. Our results suggest positive long-term returns for foreign investors in newly privatised companies. The returns are particularly high and statistically significant for investors in Polish com-panies. The long-term performance is influenced by firms? size, retained state own-ership, and the choice of a privatisation method.","PeriodicalId":126917,"journal":{"name":"European Financial Management Association Meetings (EFMA) (Archive)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116514686","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}
Points out that preference shares are much more heavily used in emerging economies than in advanced ones to finance new investment projects and develops a mathematical model to show the conditions under which companies are willing to issue them at a price which will attract investors. Outlines the tax systems in Taiwan, South Korea and New Zealand and uses the model to explain why companies in the former two countries issue preference share but New Zealand firms to not.
{"title":"Emerging Markets and Financing with Preferred Stocks: The Case of Pacific Rim Countries","authors":"Ali Fatemi, Iraj Fooladi, Nargess Kayhani","doi":"10.2139/ssrn.271071","DOIUrl":"https://doi.org/10.2139/ssrn.271071","url":null,"abstract":"Points out that preference shares are much more heavily used in emerging economies than in advanced ones to finance new investment projects and develops a mathematical model to show the conditions under which companies are willing to issue them at a price which will attract investors. Outlines the tax systems in Taiwan, South Korea and New Zealand and uses the model to explain why companies in the former two countries issue preference share but New Zealand firms to not.","PeriodicalId":126917,"journal":{"name":"European Financial Management Association Meetings (EFMA) (Archive)","volume":"94 21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129070660","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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