Using negative to low-correlated assets to manage short-term portfolio risk is not uncommon among investors,although the long-term benefits of this strategy remain unclear.This study examines the long-term benefits of...Using negative to low-correlated assets to manage short-term portfolio risk is not uncommon among investors,although the long-term benefits of this strategy remain unclear.This study examines the long-term benefits of the correlation strategy for portfolios based on the stock market in Asia,Central and Eastern Europe,the Middle East and North Africa,and Latin America from 2000 to 2016.Our strategy is as follows.We develop five portfolios based on the average unconditional correlation between domestic and foreign assets from 2000 to 2016.This yields five regional portfolios based on low to high correlations.In the presence of selected economic and financial conditions,long-term diversification gains for each regional portfolio are evaluated using a panel cointegration-based testing method.Consistent across all portfolios and regions,our key cointegration results suggest that selecting a low-correlated portfolio to maximize diversification gains does not necessarily result in long-term diversification gains.Our empirical method,which also permits the estimation of cointegrating regressions,provides the opportunity to evaluate the impact of oil prices,U.S.stock market fluctuations,and investor sentiments on regional portfolios,as well as to hedge against these fluctuations.Finally,we extend our data to cover the years 2017–2022 and find that our main findings are robust.展开更多
A universal method of molecular dating that can be applied to all families and genera regardless of their fossil records, or lack thereof, is highly desirable. A possible method for eudicots is to use a large phylogen...A universal method of molecular dating that can be applied to all families and genera regardless of their fossil records, or lack thereof, is highly desirable. A possible method for eudicots is to use a large phylogeny calibrated using deep fossils including tricolpate pollen as a fixed （124 mya） calibration point. This method was used to calculate node ages within three species-poor disjunct basal eudicot genera, Caulophyllum, Podophyllum and Pachysandra, and sensitivity of these ages to effects such as taxon sampling were then quantified. By deleting from one to three accessions related to each genus in 112 different combinations, a confidence range describing variation due only to taxon sampling was generated. Ranges for Caulophyllum, Podophyllum and Pachysandra were 8.4-10.6, 7.6-20.0, and 17.6-25.0 mya, respectively. However, the confidence ranges calculated using bootstrapping were much wider, at 3-19, 0-32 and 11-32 mya, respectively. Furthermore, deleting 10 adjacent taxa had a large effect in Pachysandra only, indicating that undersampling effects are significant among Buxales. Changes to sampling density in neighboring clades, or to the position of the fixed fossil calibration point had small to negligible effects. Non-parametric rate smoothing was more sensitive to taxon sampling effects than was penalized likelihood. The wide range for Podophyllum, compared to the other two genera, was probably due to a high degree of rate heterogeneity within this genus. Confidence ranges calculated by this method could be narrowed by sampling more individuals within the genus of interest, and by sequencing multiple DNA regions from all species in the phylogeny.展开更多
Although American libraries had begun collecting Chinese language materials in the 19th century, notably the United States Library of Congress in 1869, Yale in 1878, Harvard in 1879, and Berkeley in 1896, East Asian s...Although American libraries had begun collecting Chinese language materials in the 19th century, notably the United States Library of Congress in 1869, Yale in 1878, Harvard in 1879, and Berkeley in 1896, East Asian studies librarianship in North America, including China studies librarianship, was not fully developed until the 1960s. There was no formal organization that represented the interest of Chinese studies librarians because there were few of them and most of them were China scholars rather than trained librarians. More than 100 years later, the number of Chinese studies librarians in North America has increased considerably, primarily in response to the demand in the field of China studies and more recently to the needs of immigrant population and the general public who has an interest in China. This paper traces the history and growth of Chinese studies librarianship in North America, documents the development of the professional organization that represents Chinese studies librarians, and examines the training programs that prepare them for their jobs. It also attempts to propose an international exchange forum aiming to bring together Chinese studies librarians in North America and librarians in China in sharing their experience and expertise to achieve the ultimate goal of serving the users.展开更多
基金supported by the National Natural Science Foundation of China(No.72104075,71850012,72274056)the National Office for Philosophy and Social Sciences Fund of China(No.19AZD014),Natural Science Foundation Project of Hunan Province(No.2022JJ40106)the Hunan University Youth Talent Program.
文摘Using negative to low-correlated assets to manage short-term portfolio risk is not uncommon among investors,although the long-term benefits of this strategy remain unclear.This study examines the long-term benefits of the correlation strategy for portfolios based on the stock market in Asia,Central and Eastern Europe,the Middle East and North Africa,and Latin America from 2000 to 2016.Our strategy is as follows.We develop five portfolios based on the average unconditional correlation between domestic and foreign assets from 2000 to 2016.This yields five regional portfolios based on low to high correlations.In the presence of selected economic and financial conditions,long-term diversification gains for each regional portfolio are evaluated using a panel cointegration-based testing method.Consistent across all portfolios and regions,our key cointegration results suggest that selecting a low-correlated portfolio to maximize diversification gains does not necessarily result in long-term diversification gains.Our empirical method,which also permits the estimation of cointegrating regressions,provides the opportunity to evaluate the impact of oil prices,U.S.stock market fluctuations,and investor sentiments on regional portfolios,as well as to hedge against these fluctuations.Finally,we extend our data to cover the years 2017–2022 and find that our main findings are robust.
基金NERC (fellowship NE/B500658/1) for the financial support that made this work possible
文摘A universal method of molecular dating that can be applied to all families and genera regardless of their fossil records, or lack thereof, is highly desirable. A possible method for eudicots is to use a large phylogeny calibrated using deep fossils including tricolpate pollen as a fixed （124 mya） calibration point. This method was used to calculate node ages within three species-poor disjunct basal eudicot genera, Caulophyllum, Podophyllum and Pachysandra, and sensitivity of these ages to effects such as taxon sampling were then quantified. By deleting from one to three accessions related to each genus in 112 different combinations, a confidence range describing variation due only to taxon sampling was generated. Ranges for Caulophyllum, Podophyllum and Pachysandra were 8.4-10.6, 7.6-20.0, and 17.6-25.0 mya, respectively. However, the confidence ranges calculated using bootstrapping were much wider, at 3-19, 0-32 and 11-32 mya, respectively. Furthermore, deleting 10 adjacent taxa had a large effect in Pachysandra only, indicating that undersampling effects are significant among Buxales. Changes to sampling density in neighboring clades, or to the position of the fixed fossil calibration point had small to negligible effects. Non-parametric rate smoothing was more sensitive to taxon sampling effects than was penalized likelihood. The wide range for Podophyllum, compared to the other two genera, was probably due to a high degree of rate heterogeneity within this genus. Confidence ranges calculated by this method could be narrowed by sampling more individuals within the genus of interest, and by sequencing multiple DNA regions from all species in the phylogeny.
文摘Although American libraries had begun collecting Chinese language materials in the 19th century, notably the United States Library of Congress in 1869, Yale in 1878, Harvard in 1879, and Berkeley in 1896, East Asian studies librarianship in North America, including China studies librarianship, was not fully developed until the 1960s. There was no formal organization that represented the interest of Chinese studies librarians because there were few of them and most of them were China scholars rather than trained librarians. More than 100 years later, the number of Chinese studies librarians in North America has increased considerably, primarily in response to the demand in the field of China studies and more recently to the needs of immigrant population and the general public who has an interest in China. This paper traces the history and growth of Chinese studies librarianship in North America, documents the development of the professional organization that represents Chinese studies librarians, and examines the training programs that prepare them for their jobs. It also attempts to propose an international exchange forum aiming to bring together Chinese studies librarians in North America and librarians in China in sharing their experience and expertise to achieve the ultimate goal of serving the users.
