To build the Guangdong-Hong Kong-Macao Greater Bay Area has already become the state development strategy, indicating a new stage of the cooperation among the three places-Guangdong, Hong Kong and Marco. At the same time, the Greater Bay Area has raised the increasing interests of researchers in the fields of all kinds. The existing studies on the Guangdong-Hong Kong-Macao Greater Bay Area have been done qualitatively, mainly focusing on the functions, regional relationship and development strategies, while there lacks the research on the regional economy and its spatiotemporal evolutionary structure. In this paper, some quantitative methods have been applied to study the spatiotemporal evolutionary characteristics of the economic development in the Guangdong-Hong Kong-Macao Greater Bay Area. First, a comprehensive economic indicator system was established based on the relevant data of the Guangdong-Hong Kong-Macao Greater Bay Area from 1995 to 2015. By means of the Entropy Evaluation Method, the entropy of each indicator was determined. With the comprehensive assessment model of economic development, the level of economy in the Guangdong-Hong Kong-Macao Greater Bay Area was calculated. Secondly, the paper used relative development rate (Nich), standard deviation, variable coefficient as well as Exploratory Spatial Data Analysis to analyze the spatiotemporal evolutionary characteristics of the economy in the Guangdong-Hong Kong-Macao Greater Bay Area since 1995. Finally, the paper explored the possible influencing factors on the economic development in the Guangdong-Hong Kong-Macao Greater Bay Area. The results show that: 1) the economy developed rapidly with some fluctuations as a whole which can be divided into four stages according to its growth rate. Besides, the gross economy has increased and it developed an exported-oriented economy. However, the adjustment of industrial structure was slow. During the study period, Hong Kong and Macao experienced the highest growth rate followed by Guangzhou and Shenzhen, who have already ranked at the first level in the Bay Area; 2) the absolute disparity increased, in the contrary, the relative disparity decreased. Besides, the polarization of economy first experienced a downward trend but then it was strengthened; 3) the spatial characteristic of economy changed from polar central structure composed of Hong Kong and Macao to multi-central structure with Guangzhou and Shenzhen standing out besides Hong Kong and Macao, a reversed “U” type can be seen in the trend analysis; 4) external environment, location and regional policies turned out to be the main influencing factors on the spatiotemporal characteristics of regional economy. After 21 years’ development, the Guangdong-Hong Kong-Macao Greater Bay Area has changed its economic structure from a core-periphery to a network, which indicated the increase of the connection among the cities. In order to improve the international competition of the Guangdong-Hong Kong-Macao Greater Bay Area, this paper gave suggestions from the perspectives of industrial transformation, ecological protection, regional cooperation, cultural innovation and so forth.

To build the Guangdong-Hong Kong-Macao Greater Bay Area has already become the state development strategy, indicating a new stage of the cooperation among the three places-Guangdong, Hong Kong and Marco. At the same time, the Greater Bay Area has raised the increasing interests of researchers in the fields of all kinds. The existing studies on the Guangdong-Hong Kong-Macao Greater Bay Area have been done qualitatively, mainly focusing on the functions, regional relationship and development strategies, while there lacks the research on the regional economy and its spatiotemporal evolutionary structure. In this paper, some quantitative methods have been applied to study the spatiotemporal evolutionary characteristics of the economic development in the Guangdong-Hong Kong-Macao Greater Bay Area. First, a comprehensive economic indicator system was established based on the relevant data of the Guangdong-Hong Kong-Macao Greater Bay Area from 1995 to 2015. By means of the Entropy Evaluation Method, the entropy of each indicator was determined. With the comprehensive assessment model of economic development, the level of economy in the Guangdong-Hong Kong-Macao Greater Bay Area was calculated. Secondly, the paper used relative development rate (Nich), standard deviation, variable coefficient as well as Exploratory Spatial Data Analysis to analyze the spatiotemporal evolutionary characteristics of the economy in the Guangdong-Hong Kong-Macao Greater Bay Area since 1995. Finally, the paper explored the possible influencing factors on the economic development in the Guangdong-Hong Kong-Macao Greater Bay Area. The results show that: 1) the economy developed rapidly with some fluctuations as a whole which can be divided into four stages according to its growth rate. Besides, the gross economy has increased and it developed an exported-oriented economy. However, the adjustment of industrial structure was slow. During the study period, Hong Kong and Macao experienced the highest growth rate followed by Guangzhou and Shenzhen, who have already ranked at the first level in the Bay Area; 2) the absolute disparity increased, in the contrary, the relative disparity decreased. Besides, the polarization of economy first experienced a downward trend but then it was strengthened; 3) the spatial characteristic of economy changed from polar central structure composed of Hong Kong and Macao to multi-central structure with Guangzhou and Shenzhen standing out besides Hong Kong and Macao, a reversed “U” type can be seen in the trend analysis; 4) external environment, location and regional policies turned out to be the main influencing factors on the spatiotemporal characteristics of regional economy. After 21 years’ development, the Guangdong-Hong Kong-Macao Greater Bay Area has changed its economic structure from a core-periphery to a network, which indicated the increase of the connection among the cities. In order to improve the international competition of the Guangdong-Hong Kong-Macao Greater Bay Area, this paper gave suggestions from the perspectives of industrial transformation, ecological protection, regional cooperation, cultural innovation and so forth.

According to the observation of the data of trade between the Pearl River Delta and Hong Kong and Macao after the establishment of the PRC, we can see that the trade scale and structural changes have promoted the process of the integration of Guangdong-Hong Kong-Macao Bay Area. So, has trade played a role in the integration of Guangdong-Hong Kong-Macao Greater Bay Area? If so, how can trade play a role in promoting the process of integration as an integrated link in the development of the Greater Bay Area between Guangdong and Hong Kong and Macao? On the basis of summarizing the existing trade theory and empirical researches, the article develops a long-term dynamic theory of the trade's role in the integration and explains the process of the integration of Guangdong-Hong Kong-Macao Greater Bay Area. In this article, the process is divided into three phases of natural stage in chronological order since the establishment of the PRC to demonstrate the point above-mentioned. The first stage is the time after the founding of the PRC and before the reform and opening up. In this period, trade of goods dominated by primary commodities was the source of regional cooperation in Guangdong, Hong Kong and Macao. Since the reform and opening up, the Guangdong- Hong Kong- Macao regional cooperation has made great progress. The rise of cross-border production and trade with industrial transfer as the mainstay has greatly broken the bias of development between Hong Kong, Macao and the Pearl River Delta. The frequent exchanges between Guangdong, Hong Kong and Macao have led to the rapid economic growth of the three regions and the emergence of trade in the east and west of the Pearl River Delta. The phenomenon of industrial clusters has promoted the deepening of infrastructure in the three regions. In the third stage, starting from China's accession to the WTO in 2001, China's economy has been further more open to the world. Hong Kong and Macao, which have extensive experience in international standards, have become the vanguard of the country's active integration with globalization. In 2003, the Mainland and Hong Kong and Macao signed CEPA on the basis of improving the liquidity of commodity trade. Besides, a series of supplementary agreements have also promoted the flow of production trade and service trade from Hong Kong and Macao to the Pearl River Delta cities. With the close trade and service trade, the degree of innovation and knowledge spillover has also been enhanced. The conclusion of this paper is that trade has played a catalytic role in the process of the integration of Guangdong-Hong Kong-Macao Greater Bay Area. By changing the target of trade from goods to production and finally to service, the main body of trade, from physical goods to intangible goods, is the major process of promoting the integration of the Greater Bay Area of Guangdong, Hong Kong and Macao, from the primary to the more advanced one. In addition, the process of trade integration has a great spillover effect and it has perfected the regional basic road network. What’s more, the construction of industrial clusters has promoted the emergence of industrial clusters, boosted regional innovation and pushed the integrated area to a new platform for cooperation. The article summarizes the literature on trade and regional integration and would have some theoretical significance. Based on the summary of existing trade theories and empirical studies, the paper develops the conjecture on the dynamic role of trade in regional integration over a long period of time. And through the empirical demonstration of integration of Guangdong, Hong Kong, Macao Bay area, it has laid the foundation for the dynamic role of integration theory in the future study.

According to the observation of the data of trade between the Pearl River Delta and Hong Kong and Macao after the establishment of the PRC, we can see that the trade scale and structural changes have promoted the process of the integration of Guangdong-Hong Kong-Macao Bay Area. So, has trade played a role in the integration of Guangdong-Hong Kong-Macao Greater Bay Area? If so, how can trade play a role in promoting the process of integration as an integrated link in the development of the Greater Bay Area between Guangdong and Hong Kong and Macao? On the basis of summarizing the existing trade theory and empirical researches, the article develops a long-term dynamic theory of the trade's role in the integration and explains the process of the integration of Guangdong-Hong Kong-Macao Greater Bay Area. In this article, the process is divided into three phases of natural stage in chronological order since the establishment of the PRC to demonstrate the point above-mentioned. The first stage is the time after the founding of the PRC and before the reform and opening up. In this period, trade of goods dominated by primary commodities was the source of regional cooperation in Guangdong, Hong Kong and Macao. Since the reform and opening up, the Guangdong- Hong Kong- Macao regional cooperation has made great progress. The rise of cross-border production and trade with industrial transfer as the mainstay has greatly broken the bias of development between Hong Kong, Macao and the Pearl River Delta. The frequent exchanges between Guangdong, Hong Kong and Macao have led to the rapid economic growth of the three regions and the emergence of trade in the east and west of the Pearl River Delta. The phenomenon of industrial clusters has promoted the deepening of infrastructure in the three regions. In the third stage, starting from China's accession to the WTO in 2001, China's economy has been further more open to the world. Hong Kong and Macao, which have extensive experience in international standards, have become the vanguard of the country's active integration with globalization. In 2003, the Mainland and Hong Kong and Macao signed CEPA on the basis of improving the liquidity of commodity trade. Besides, a series of supplementary agreements have also promoted the flow of production trade and service trade from Hong Kong and Macao to the Pearl River Delta cities. With the close trade and service trade, the degree of innovation and knowledge spillover has also been enhanced. The conclusion of this paper is that trade has played a catalytic role in the process of the integration of Guangdong-Hong Kong-Macao Greater Bay Area. By changing the target of trade from goods to production and finally to service, the main body of trade, from physical goods to intangible goods, is the major process of promoting the integration of the Greater Bay Area of Guangdong, Hong Kong and Macao, from the primary to the more advanced one. In addition, the process of trade integration has a great spillover effect and it has perfected the regional basic road network. What’s more, the construction of industrial clusters has promoted the emergence of industrial clusters, boosted regional innovation and pushed the integrated area to a new platform for cooperation. The article summarizes the literature on trade and regional integration and would have some theoretical significance. Based on the summary of existing trade theories and empirical studies, the paper develops the conjecture on the dynamic role of trade in regional integration over a long period of time. And through the empirical demonstration of integration of Guangdong, Hong Kong, Macao Bay area, it has laid the foundation for the dynamic role of integration theory in the future study.

The concept of megalopolis, since its original inception six decades ago, has inspired many new terms that mainly describe large-scale urbanized forms such as megaregions and polycentric urban regions. However, recent studies have increasingly focused on the two key functions that megalopolises act as an incubator of new ideas and trends and as a hub that articulates knowledge exchange at the megalopolitan, national, and global scales. While the recent studies have mainly analyzed the functional aspects of megalopolis based on China's Yangtze River Delta region, this paper investigates the evolving process and mechanisms of knowledge collaboration within and beyond Guangdong-Hong Kong-Macao Greater Bay Area (GBA) - one of the most promising and vibrant megalopolises in China. In addition, the GBA megalopolis is unique because it contains Hong Kong and Macao, which have a different political system from China's mainland. Drawing upon a dataset of publications that were indexed in Web of Science Core Collection during the 1990-2016 period, this paper uses the Gini coefficient to measure the degree of knowledge polycentricity of the GBA megalopolis. Here, knowledge polycentricity is further classified into attribute polycentricity of knowledge production and functional polycentricity of knowledge collaboration within and beyond the GBA megalopolis. Whereas the attribute polycentricity refers to the distribution inequality of the total publications of GBA cities, the functional polycentricity represents the distribution inequality of GBA cities' knowledge collaboration at different geographical scales. Our empirical results show: (1) knowledge production of the GBA megalopolis as a whole has experienced a robust and continuous growth. The degrees of both attribute polycentricity and functional polycentricity have also been on the increase in general, although there are some fluctuations in early years and some deviations in recent years. During the ten years after Hong Kong and Macao returned to China (the 2000-2010 period), the degree of knowledge polycentricity of the GBA megalopolis especially enjoyed the fastest rise; (2) The degree of functional polycentricity decreased with the expansion in the geographical scales at which it is measured, confirming the findings of previous studies that functional polycentricity is scale-dependent. Moreover, we find that the degree of functional polycentricity becomes more fluctuated at the global scale while it tends to increase continuously at the megalopolitan scale; (3) The evolving process of knowledge polycentricity of the GBA megalopolis is influenced by institutional proximity, geographical proximity and status proximity between cities. Specifically, the mobility of researchers, the collaboration of universities and research institutes, and the coordination of local governments are three major forces promoting the evolution of knowledge polycentricity of the GBA megalopolis. Overall, the increasing knowledge polycentricity would be of significance for the GBA megalopolis to form a knowledge-driven region of collective collaboration.

The concept of megalopolis, since its original inception six decades ago, has inspired many new terms that mainly describe large-scale urbanized forms such as megaregions and polycentric urban regions. However, recent studies have increasingly focused on the two key functions that megalopolises act as an incubator of new ideas and trends and as a hub that articulates knowledge exchange at the megalopolitan, national, and global scales. While the recent studies have mainly analyzed the functional aspects of megalopolis based on China's Yangtze River Delta region, this paper investigates the evolving process and mechanisms of knowledge collaboration within and beyond Guangdong-Hong Kong-Macao Greater Bay Area (GBA) - one of the most promising and vibrant megalopolises in China. In addition, the GBA megalopolis is unique because it contains Hong Kong and Macao, which have a different political system from China's mainland. Drawing upon a dataset of publications that were indexed in Web of Science Core Collection during the 1990-2016 period, this paper uses the Gini coefficient to measure the degree of knowledge polycentricity of the GBA megalopolis. Here, knowledge polycentricity is further classified into attribute polycentricity of knowledge production and functional polycentricity of knowledge collaboration within and beyond the GBA megalopolis. Whereas the attribute polycentricity refers to the distribution inequality of the total publications of GBA cities, the functional polycentricity represents the distribution inequality of GBA cities' knowledge collaboration at different geographical scales. Our empirical results show: (1) knowledge production of the GBA megalopolis as a whole has experienced a robust and continuous growth. The degrees of both attribute polycentricity and functional polycentricity have also been on the increase in general, although there are some fluctuations in early years and some deviations in recent years. During the ten years after Hong Kong and Macao returned to China (the 2000-2010 period), the degree of knowledge polycentricity of the GBA megalopolis especially enjoyed the fastest rise; (2) The degree of functional polycentricity decreased with the expansion in the geographical scales at which it is measured, confirming the findings of previous studies that functional polycentricity is scale-dependent. Moreover, we find that the degree of functional polycentricity becomes more fluctuated at the global scale while it tends to increase continuously at the megalopolitan scale; (3) The evolving process of knowledge polycentricity of the GBA megalopolis is influenced by institutional proximity, geographical proximity and status proximity between cities. Specifically, the mobility of researchers, the collaboration of universities and research institutes, and the coordination of local governments are three major forces promoting the evolution of knowledge polycentricity of the GBA megalopolis. Overall, the increasing knowledge polycentricity would be of significance for the GBA megalopolis to form a knowledge-driven region of collective collaboration.

Most recently, China has proposed the Belt and Road initiative in an effort to establish a form of multilateral trade cooperation mechanism. This initiative is meaningful for the construction of a healthy global economic structure and the breaking of US-initiated hegemony global economic structure. The notion of "Guangdong-Hong Kong-Macao Greater Bay Area" is a refresh regional concept developed exactly in such a context. In this sense, this notion is inevitably imbued with the meaning of political geography. This article therefore argues that studies related to the Guangdong-Hong Kong-Macao Greater Bay Area should not be limited to discussions within segregated practical disciplines, but considered on the macro-level, such as with the perspectives of political geography. In so doing, this article puts forward some suggestions from the lens of modern "vertical-horizontal" spatial management system, the integration of geo-cultures, and geo-economy. First, this article insists that the proposal of the concept of bay economy itself is a type of spatial management thoughts that stresses "upscaling." The development of the Guangdong-Hong Kong-Macao Greater Bay Area is under a rather complex and multi-scale space structure that should pay attention to the competitive and cooperative relations among different cities and regions. It is important to adjust the scale, in particular to the national scale to tackle problems faced in the process of integrating the development of the whole area. Second, this article argues that there is a potential for weakening the integration of various geo-cultures in the process of developing the Guangdong-Hong Kong-Macao Greater Bay Area. It is very important to discuss how to deal with the "identity crisis" between Hong Kong and the mainland of China, which, to a significant extent, provides stable social environment for the development of the Guangdong-Hong Kong-Macao Greater Bay Area. Third, this article argues that it is important to put the development of the Guangdong-Hong Kong-Macao Greater Bay Area into the framework of geo-economy, which underlines the importance of the requirement of the state power on economic development as well as the importance of economic development on power exercises. Finally, this article proposes an agenda to generate suggestions on the scientific development of the Guangdong-Hong Kong-Macao Greater Bay Area from multiple perspectives in other disciplines in the future.

Most recently, China has proposed the Belt and Road initiative in an effort to establish a form of multilateral trade cooperation mechanism. This initiative is meaningful for the construction of a healthy global economic structure and the breaking of US-initiated hegemony global economic structure. The notion of "Guangdong-Hong Kong-Macao Greater Bay Area" is a refresh regional concept developed exactly in such a context. In this sense, this notion is inevitably imbued with the meaning of political geography. This article therefore argues that studies related to the Guangdong-Hong Kong-Macao Greater Bay Area should not be limited to discussions within segregated practical disciplines, but considered on the macro-level, such as with the perspectives of political geography. In so doing, this article puts forward some suggestions from the lens of modern "vertical-horizontal" spatial management system, the integration of geo-cultures, and geo-economy. First, this article insists that the proposal of the concept of bay economy itself is a type of spatial management thoughts that stresses "upscaling." The development of the Guangdong-Hong Kong-Macao Greater Bay Area is under a rather complex and multi-scale space structure that should pay attention to the competitive and cooperative relations among different cities and regions. It is important to adjust the scale, in particular to the national scale to tackle problems faced in the process of integrating the development of the whole area. Second, this article argues that there is a potential for weakening the integration of various geo-cultures in the process of developing the Guangdong-Hong Kong-Macao Greater Bay Area. It is very important to discuss how to deal with the "identity crisis" between Hong Kong and the mainland of China, which, to a significant extent, provides stable social environment for the development of the Guangdong-Hong Kong-Macao Greater Bay Area. Third, this article argues that it is important to put the development of the Guangdong-Hong Kong-Macao Greater Bay Area into the framework of geo-economy, which underlines the importance of the requirement of the state power on economic development as well as the importance of economic development on power exercises. Finally, this article proposes an agenda to generate suggestions on the scientific development of the Guangdong-Hong Kong-Macao Greater Bay Area from multiple perspectives in other disciplines in the future.

Urban region is an important spatial organization form of economic globalization and regional integration trends. Functional polycentricity is the most essential features and the most critical stage of evolution to city region. In the flowing space and urban network theory, functional polycentricity study of urban regions can unfold from intercity functional connection with quantitative measurement and qualitative analysis approaches. In this article, the Zhujiang River Delta urban areas for the study, we carry on the discussion to the functional polycentricity of the Zhujiang River Delta region based on the data of intercity rail traffic flow. Research shows that, intercity rail traffic flow functional relation of the region has a high level of functional polycentricity of the Zhujiang River Delta which include in the middle and upper levels of typical cities or regions in the world. With the measurement and analysis of functional polycentripolycentriccity for the eastern and western wings, it shows that there lacks seffective intercity rail transportation contact between eastern and western wings, which has a serious negative impact on thefunctional polycentricity of the Zhujiang River Delta. The functional polycentricity development of the Zhujiang River Delta has entered the centrifugal stage. Along with the development of the intercity rail transit construction and regional integration, the region of the multifunctional center will tend to be mature.

Urban region is an important spatial organization form of economic globalization and regional integration trends. Functional polycentricity is the most essential features and the most critical stage of evolution to city region. In the flowing space and urban network theory, functional polycentricity study of urban regions can unfold from intercity functional connection with quantitative measurement and qualitative analysis approaches. In this article, the Zhujiang River Delta urban areas for the study, we carry on the discussion to the functional polycentricity of the Zhujiang River Delta region based on the data of intercity rail traffic flow. Research shows that, intercity rail traffic flow functional relation of the region has a high level of functional polycentricity of the Zhujiang River Delta which include in the middle and upper levels of typical cities or regions in the world. With the measurement and analysis of functional polycentripolycentriccity for the eastern and western wings, it shows that there lacks seffective intercity rail transportation contact between eastern and western wings, which has a serious negative impact on thefunctional polycentricity of the Zhujiang River Delta. The functional polycentricity development of the Zhujiang River Delta has entered the centrifugal stage. Along with the development of the intercity rail transit construction and regional integration, the region of the multifunctional center will tend to be mature.

From the spatial scale of prefecture-level city and county area, this article establishes an evaluation index system of the urban comprehensive power of Zhujiang River Delta (ZJRD) urban agglomeration to analyze the urban comprehensive power in 1990, 1994, 2000, 2005 and 2009, respectively. Moreover, the spatial interaction level among the ZJRD cities and the potential value of each city are calculated using the improved gravity model and potential model. By these results, some GIS spatial analysis methods such as space thematic map expression method and space interpolation method, etc. are used to analyze the spatio-temporal evolution of the urban space interaction of ZJRD urban agglomeration in recent 20 years. The basic conclusions are obtained as follows: 1) The spatial contact among the ZJRD prefecture-level cities has been gradually strengthened as a whole, and the centrality of Guangzhou in the region is reflected. 2) At county-level scale, the linkage between urban area and counties under the same prefecture-level city, the linkage among urban districts of prefecture-level cities and counties in the Guangzhou-Foshan metropolitan region are strong, while the spatial linkage among other counties and cities is weak. The spatial linkage among most counties at the core region of ZJRD has been gradually strengthened as a whole, however, the spatial linkage among counties out the core region and the spatial linkage between the counties at the inner core region of ZJRD urban agglomeration and counties out the core region go up and down frequently all the way and have no discernible regularity. 3) The city potential values of Guangzhou-Foshan metropolitan region and Shenzhen-Dongguan-Huizhou metropolitan region are all strong and fluctuate pronouncedly. And the diffusivity of these two regions is also stronger than the other. The potential values of other cities are relatively lower and show no obvious fluctuation. 4) There is significant imbalance of the city potential between districts. The features and evolution laws of spatial differentiation and spatial diffusivity of the city potential in ZJRD urban agglomeration are obvious and unrest under stability.

From the spatial scale of prefecture-level city and county area, this article establishes an evaluation index system of the urban comprehensive power of Zhujiang River Delta (ZJRD) urban agglomeration to analyze the urban comprehensive power in 1990, 1994, 2000, 2005 and 2009, respectively. Moreover, the spatial interaction level among the ZJRD cities and the potential value of each city are calculated using the improved gravity model and potential model. By these results, some GIS spatial analysis methods such as space thematic map expression method and space interpolation method, etc. are used to analyze the spatio-temporal evolution of the urban space interaction of ZJRD urban agglomeration in recent 20 years. The basic conclusions are obtained as follows: 1) The spatial contact among the ZJRD prefecture-level cities has been gradually strengthened as a whole, and the centrality of Guangzhou in the region is reflected. 2) At county-level scale, the linkage between urban area and counties under the same prefecture-level city, the linkage among urban districts of prefecture-level cities and counties in the Guangzhou-Foshan metropolitan region are strong, while the spatial linkage among other counties and cities is weak. The spatial linkage among most counties at the core region of ZJRD has been gradually strengthened as a whole, however, the spatial linkage among counties out the core region and the spatial linkage between the counties at the inner core region of ZJRD urban agglomeration and counties out the core region go up and down frequently all the way and have no discernible regularity. 3) The city potential values of Guangzhou-Foshan metropolitan region and Shenzhen-Dongguan-Huizhou metropolitan region are all strong and fluctuate pronouncedly. And the diffusivity of these two regions is also stronger than the other. The potential values of other cities are relatively lower and show no obvious fluctuation. 4) There is significant imbalance of the city potential between districts. The features and evolution laws of spatial differentiation and spatial diffusivity of the city potential in ZJRD urban agglomeration are obvious and unrest under stability.

High-throughput neurotransmission at ribbon synapses of cochlear inner hair cells (IHCs) requires tight coupling of neurotransmitter release and balanced recycling of synaptic vesicles (SVs) as well as rapid restoration of release sites. Here, we examined the role of the adaptor protein AP180 for IHC synaptic transmission in AP180-KO mice using high-pressure freezing and electron tomography, confocal microscopy, patch-clamp membrane-capacitance measurements and systems physiology. AP180 was found predominantly at the synaptic pole of IHCs. AP180-deficient IHCs had severely reduced SV numbers, slowed endocytic membrane retrieval, and accumulated endocytic intermediates near ribbon synapses, indicating that AP180 is required for clathrin-dependent endocytosis and SV reformation in IHCs. Moreover, AP180 deletion led to a high prevalence of SVs in a multi-tethered or docked state after stimulation, a reduced rate of SV replenishment, and a hearing impairment. We conclude that, in addition to its role in clathrin recruitment, AP180 contributes to release site clearance in IHCs.

High-throughput neurotransmission at ribbon synapses of cochlear inner hair cells (IHCs) requires tight coupling of neurotransmitter release and balanced recycling of synaptic vesicles (SVs) as well as rapid restoration of release sites. Here, we examined the role of the adaptor protein AP180 for IHC synaptic transmission in AP180-KO mice using high-pressure freezing and electron tomography, confocal microscopy, patch-clamp membrane-capacitance measurements and systems physiology. AP180 was found predominantly at the synaptic pole of IHCs. AP180-deficient IHCs had severely reduced SV numbers, slowed endocytic membrane retrieval, and accumulated endocytic intermediates near ribbon synapses, indicating that AP180 is required for clathrin-dependent endocytosis and SV reformation in IHCs. Moreover, AP180 deletion led to a high prevalence of SVs in a multi-tethered or docked state after stimulation, a reduced rate of SV replenishment, and a hearing impairment. We conclude that, in addition to its role in clathrin recruitment, AP180 contributes to release site clearance in IHCs.

Geo-relationships, as an important field of research in geography, have attracted much attention from scholars. Quantitative research on geo-relationships based on big data is an important supplement to traditional geo-relationships study. This paper uses GDELT mass media data to express the geo-relationships between China and its neighboring countries as a global relationship of cooperation and conflict, and identifies the stage division of these relationships using ordered cluster analysis. Social network analysis is conducted for each stage of the cooperation and conflict relationship, and community detection is used to further analyze and interpret the networks of cooperation and conflict. Finally, we highlight bilateral relations in various stages and conduct a China-centered equilibrium analysis. Three main results are presented. First, from 1979 to 2017, the cooperation and conflict relationship between China and its neighboring countries demonstrated an obvious three-stage temporal division. China has gradually become the center of the network, and a broad cooperation pattern centered on China and supported by Russia, Japan, and South Korea has formed. Second, the highlighted bilateral relations in each stage, such as China-Vietnam, China-Japan, China-Russia, and DPRK-ROK, show varied development trends and driving factors. Third, with the process of China's peaceful rise, cooperation between the country and its neighbors is becoming more and more balanced, and conflict between them is expanding.

Geo-relationships, as an important field of research in geography, have attracted much attention from scholars. Quantitative research on geo-relationships based on big data is an important supplement to traditional geo-relationships study. This paper uses GDELT mass media data to express the geo-relationships between China and its neighboring countries as a global relationship of cooperation and conflict, and identifies the stage division of these relationships using ordered cluster analysis. Social network analysis is conducted for each stage of the cooperation and conflict relationship, and community detection is used to further analyze and interpret the networks of cooperation and conflict. Finally, we highlight bilateral relations in various stages and conduct a China-centered equilibrium analysis. Three main results are presented. First, from 1979 to 2017, the cooperation and conflict relationship between China and its neighboring countries demonstrated an obvious three-stage temporal division. China has gradually become the center of the network, and a broad cooperation pattern centered on China and supported by Russia, Japan, and South Korea has formed. Second, the highlighted bilateral relations in each stage, such as China-Vietnam, China-Japan, China-Russia, and DPRK-ROK, show varied development trends and driving factors. Third, with the process of China's peaceful rise, cooperation between the country and its neighbors is becoming more and more balanced, and conflict between them is expanding.

The Belt and Road initiative has become China's basic international policy. Keeping abreast of the social development trend of countries along the Belt and Road is crucial to ensuring the steady progress and successful implementation of the initiative. To this end, this study used the Global Data on Events, Location and Tone (GDELT) as a data source to obtain the full-text English news data in 25 countries along the Belt and Road in the past five years, and analyzed the social development trends of various countries by introducing topic models and combining an unsupervised method—the latent Dirichlet allocation (LDA) and a supervised method—labeled latent Dirichlet allocation (Labeled LDA) to mine the topics contained in the news data, and construct a social stability model. The study found that: 1) The social development trend of the countries along the Belt and Road is uneven, and the countries can be divided into four categories: Stable, such as Oman, Vietnam; Relatively stable, such as Uzbekistan, Iran; Moderate risk, such as Kuwait, Jordan, Pakistan, Myanmar; High risk, such as Syria, Afghanistan. 2) Through the spatiotemporal mining of news topics, hot spots can be effectively identified. For example, this study found that Andijon has an important influence on the social development and stability of Central Asia. 3) The supervised topic model could reveal Uzbekistan's economic and industrial structure, identify major social events, and discover its social security risks and trend. This method can effectively explore the spatiotemporal changes of news events, discover potential risks of countries, support real-time dynamic monitoring of the social development trends of countries along the Belt and Road, and provide auxiliary decision support for the implementation of the Belt and Road initiative, and thus has important application value.

The Belt and Road initiative has become China's basic international policy. Keeping abreast of the social development trend of countries along the Belt and Road is crucial to ensuring the steady progress and successful implementation of the initiative. To this end, this study used the Global Data on Events, Location and Tone (GDELT) as a data source to obtain the full-text English news data in 25 countries along the Belt and Road in the past five years, and analyzed the social development trends of various countries by introducing topic models and combining an unsupervised method—the latent Dirichlet allocation (LDA) and a supervised method—labeled latent Dirichlet allocation (Labeled LDA) to mine the topics contained in the news data, and construct a social stability model. The study found that: 1) The social development trend of the countries along the Belt and Road is uneven, and the countries can be divided into four categories: Stable, such as Oman, Vietnam; Relatively stable, such as Uzbekistan, Iran; Moderate risk, such as Kuwait, Jordan, Pakistan, Myanmar; High risk, such as Syria, Afghanistan. 2) Through the spatiotemporal mining of news topics, hot spots can be effectively identified. For example, this study found that Andijon has an important influence on the social development and stability of Central Asia. 3) The supervised topic model could reveal Uzbekistan's economic and industrial structure, identify major social events, and discover its social security risks and trend. This method can effectively explore the spatiotemporal changes of news events, discover potential risks of countries, support real-time dynamic monitoring of the social development trends of countries along the Belt and Road, and provide auxiliary decision support for the implementation of the Belt and Road initiative, and thus has important application value.

In 2001, Friedman et al. conjectured the existence of a "firewall effect" in which individuals who are infected with HIV, but remain in a state of low infectiousness, serve to prevent the virus from spreading. To evaluate this historical conjecture, we develop a new graph-theoretic measure that quantifies the extent to which Friedman's firewall hypothesis(FH)holds in a risk network. We compute this new measure across simulated trajectories of a stochastic discrete dynamical system that models a social network of 25,000 individuals engaging in risk acts over a period of 15 years. The model's parameters are based on analyses of data collected in prior studies of the real-world risk networks of people who inject drugs (PWID) in New York City. Analysis of system trajectories reveals the structural mechanisms by which individuals with mature HIV infections tend to partition the network into homogeneous clusters (with respect to infection status) and how uninfected clusters remain relatively stable (with respect to infection status) over long stretches of time. We confirm the spontaneous emergence of network firewalls in the system and reveal their structural role in the nonspreading of HIV.

Given the modern background of economic globalization, regional economic integration, new global economic development trends caused by modern technological reforms, the Belt and Road initiative, and the Guangdong-Hong Kong-Macao Greater Bay Area development strategy, there is a growing sense of urgency, necessity, and practical significance in achieving the joint development of the Guangdong-Hong Kong-Macao region. This requires an in-depth understanding and accurate grasp of the key scientific issues and important topics related to this task. This article argues that research related to the joint development of the Guangdong-Hong Kong-Macau region must be based on a regionally unified theoretical framework, "global-local" scale theory, and regional spatial interaction theory as its theoretical basis. In this regard, key scientific issues include the study of the theory of regional linkages of scale in Guangdong, Hong Kong, and Macau under the "One Country, Two Systems" framework, and the exploration of mechanisms, factors, models, and pathways governing linkages in the Guangdong-Hong Kong-Macau region. In so doing, this article proposes four important topics that can be considered with regard to the joint development of the Guangdong-Hong Kong-Macau region: (1) Research and exploration of unification/coordination theory in the Guangdong-Hong Kong-Macau region under the "One Country, Two Systems" framework; (2) Research related to the location and role of the Guangdong-Hong Kong-Macau region; (3) Research related to the multi-scale and multi-agent impact mechanisms and models for the linkages between Guangdong, Hong Kong, and Macau; (4) Research related to implementation pathways for the unified development of Guangdong, Hong Kong, and Macau.

Given the modern background of economic globalization, regional economic integration, new global economic development trends caused by modern technological reforms, the Belt and Road initiative, and the Guangdong-Hong Kong-Macao Greater Bay Area development strategy, there is a growing sense of urgency, necessity, and practical significance in achieving the joint development of the Guangdong-Hong Kong-Macao region. This requires an in-depth understanding and accurate grasp of the key scientific issues and important topics related to this task. This article argues that research related to the joint development of the Guangdong-Hong Kong-Macau region must be based on a regionally unified theoretical framework, "global-local" scale theory, and regional spatial interaction theory as its theoretical basis. In this regard, key scientific issues include the study of the theory of regional linkages of scale in Guangdong, Hong Kong, and Macau under the "One Country, Two Systems" framework, and the exploration of mechanisms, factors, models, and pathways governing linkages in the Guangdong-Hong Kong-Macau region. In so doing, this article proposes four important topics that can be considered with regard to the joint development of the Guangdong-Hong Kong-Macau region: (1) Research and exploration of unification/coordination theory in the Guangdong-Hong Kong-Macau region under the "One Country, Two Systems" framework; (2) Research related to the location and role of the Guangdong-Hong Kong-Macau region; (3) Research related to the multi-scale and multi-agent impact mechanisms and models for the linkages between Guangdong, Hong Kong, and Macau; (4) Research related to implementation pathways for the unified development of Guangdong, Hong Kong, and Macau.