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This paper extends endogenous economic growth models to incorporate knowledge externality. We explore whether spatial knowledge spillovers among regions exist, whether spatial knowledge spillovers promote regional innovative activities, and whether external knowledge spillovers affect the evolution of regional innovations in the long run. We empirically verify the theoretical results through applying spatial statistics and econometric models in the analysis of panel data of 31 regions in China. An accurate estimate of the range of knowledge spillovers is achieved and the convergence of regional knowledge growth rate is found, with clear evidences that developing regions benefit more from external knowledge spillovers than developed regions. [ABSTRACT FROM AUTHOR]

This paper analysed the evolution of landslide research and research foci in different countries. The data comprise 3105 landslide SCI articles published between January 1977 and June 2015 from the Web of Science. The data are extracted under interaction constraints of the journal title, category, and keywords. The complex network method is used for the analysis. First, from the perspective of topics and methods, the evolution is systematically assessed by generating a co-citation network of the articles and a semantic cluster analysis. Second, from the perspective of topics and landslide-related disasters, the focus in different countries is discussed by generating co-occurrence networks. These networks are the co-occurrence of the countries and keywords, and the co-occurrence of countries and landslide-related disaster phrases. The main conclusions are as follows: (1) landslide susceptibility analysis and methods of machine learning are popular research topics and methods, respectively. The topics change through time, and the article output is influenced by increasing landslide-related disasters, increasing economic losses and casualties, a desire for a more complete and accurate landslide inventory, and the use of effective methods, such as geographical information Science (GIS) and machine learning. (2) The research focus in each country is related with the country-specific disasters or economic costs caused by landslides to some degree. In addition to Italy and the USA, China is the country most commonly affected by landslides, and it should develop its own landslide database and complete in-depth studies of disaster mitigation. [ABSTRACT FROM AUTHOR]

This paper addresses the Phanerozoic tectonic evolution of the western Tarim Basin based on an integrated stratigraphic, structural and tectonic analysis. P-wave velocity data show that the basin has a stable and rigid basement. The western Tarim Basin experienced a complex tectonic evolutionary history, and this evolution can be divided into six stages: Neoproterozoic to Early Ordovician, Middle Ordovician to Middle Devonian, Late Devonian to Permian, Triassic, Jurassic to Cretaceous and Paleogene to Quaternary. The western Tarim Basin was a rift basin in the Neoproterozoic to Early Ordovician. From the Middle Ordovician to Middle Devonian, the basin consisted of a flexural depression in the south and a depression that changed from a rift depression to a flexural depression in the north during each period, i.e., the Middle–Late Ordovician and the Silurian to Middle Devonian. During the Late Devonian to Permian, the basin was a depression basin early and then changed into a flexural basin late in each period, i.e., the Late Devonian to Carboniferous and the Permian. In the Triassic, the basin was a foreland basin, and from the Jurassic to Cretaceous, it was a downwarped basin. After the Paleogene, the basin became a rejuvenated foreland basin. Based on two cross sections, we conclude that the extension and shortening in the profile reflect the tectonic evolution of the Tarim Basin. The Tarim Basin has become a composite and superimposed sedimentary basin because of its long-term and complicated tectonic evolutionary history, highly rigid and stable basement and large size. [ABSTRACT FROM AUTHOR]

Plagiognathops microlepis is an economic freshwater fish in the subfamily Xenocyprinae of Cyprinidae. It is widely distributed in the freshwater ecosystem of China, with moderate economic value and broad development prospects. However, the lack of genomic resources has limited our understanding on the genetic basis, phylogenetic status and adaptive evolution strategies of this fish. Here, we assembled a chromosome-level reference genome of P. microlepis by integrating Pacbio HiFi long-reads, Illumina short-reads and Hi-C sequencing data. The size of this genome is 1004.34 Mb with a contig N50 of 38.80 Mb. Using Hi-C sequencing data, 99.59% of the assembled sequences were further anchored to 24 chromosomes. A total of 578.91 Mb repeat sequences and 28,337 protein-coding genes were predicted in the current genome, of which, 26,929 genes were functionally annotated. This genome provides valuable information for investigating the phylogeny and evolutionary history of cyprinid fishes, as well as the genetic basis of adaptive strategies and special traits in P. microlepis. [ABSTRACT FROM AUTHOR]

The Holocene hydrological regime on the Heixiazi Island is critical for understanding the evolution of the East Asian summer monsoon (EASM) for the island's climate-sensitive location on the northern fringe of the EASM domain. In this paper, a marsh depression on the central island was selected to reconstruct the locally hydrological variation and to discuss its indications for the Holocene EASM evolution. This work is based on multi-proxy (magnetic susceptibility, grain size, loss-on-ignition, and carbonate content) analyses of 22 modern sedimentary samples with a water-level gradient of 0–66 cm and 100 cored sedimentary samples covering last ~ 9.0 ka BP. The proxies' hydrological significance was previously interpreted by the 22 modern samples using linear regression equations to construct their relationships to water-level changes. Among these proxies, the magnetic susceptibility, carbonate content, as well as the Md and sand fraction of grain size exhibit high-level relationships against the water-level changes with R2 > 0.6. Thus, these four proxies' linear-regression equations were selected and used on the 100 cored samples, and the Holocene water-level changes in the studied depression were quantitatively reconstructed. It shows that two relatively high water-level stages with strengthened EASM occurred during 8.0–4.5 ka BP and 3.0–1.4 ka BP, which were alternated by three low water-level stages with declined EASM during ~ 9.0–8.0 ka BP, 4.5–3.0 ka BP, and 1.4–0 ka BP, respectively. Among these fluctuations, the highest water-level stage with most strengthened EASM which is defined as the Holocene Monsoon Maximum occurred during 6.4–4.5 ka BP. Such a new evolution pattern of the EASM can be further supported by a large variety of records from monsoon-margin regions. We suggest the Holocene EASM evolution was generally associated with the thermal conditions in both the inner Eurasia landmass and the West Pacific Ocean, with an exception of the weak EASM before 8.0 ka BP due to the enhanced Siberia High with the dominance of the Eurasia ice sheet in the early Holocene. [ABSTRACT FROM AUTHOR]

Intense public interest in scientific claims about COVID-19, concerning its origins, modes of spread, evolution, and preventive and therapeutic strategies, has focused attention on the values to which scientists are assumed to be committed and the relationship between science and other public discourses. A much discussed claim, which has stimulated several inquiries and generated far-reaching political and economic consequences, has been that SARS-CoV-2 was deliberately engineered at the Wuhan Institute of Virology and then, either inadvertently or otherwise, released to the public by a laboratory worker. This has been pursued despite a clear refutation, through comprehensive genomic analysis, of the hypothesis that the virus was deliberately engineered and the failure of detailed investigations to identify any evidence in support of a laboratory leak. At the same time a substantial, established body of knowledge about the many factors underlying the emergence of novel zoonotic diseases has been largely ignored—including climate change and other mechanisms of environmental destruction, tourism, patterns of trade, and cultural influences. The existence and conduct of these debates have raised questions about the vulnerability of science to manipulation for political purposes. Scientific discourses are vulnerable because: (i) claims can be made with no more than probabilistic force; (ii) alleged "facts" are always subject to interpretation, which depends on social, ethical, and epistemological assumptions; and (iii) science and scientists are not inherently committed to any single set of values and historically have served diverse, and sometimes perverse, social and political interests. In the face of this complexity, the COVID-19 experience highlights the need for processes of ethical scrutiny of the scientific enterprise and its strategic deployment. To ensure reliability of truth claims and protection from corrupting influences robust ethical discourses are required that are independent of, and at times even contrary to, those of science itself. [ABSTRACT FROM AUTHOR]

The Ediacaran Period (~635–539 Ma) is marked by the emergence and diversification of complex metazoans linked to ocean redox changes, but the processes and mechanism of the redox evolution in the Ediacaran ocean are intensely debated. Here we use mercury isotope compositions from multiple black shale sections of the Doushantuo Formation in South China to reconstruct Ediacaran oceanic redox conditions. Mercury isotopes show compelling evidence for recurrent and spatially dynamic photic zone euxinia (PZE) on the continental margin of South China during time intervals coincident with previously identified ocean oxygenation events. We suggest that PZE was driven by increased availability of sulfate and nutrients from a transiently oxygenated ocean, but PZE may have also initiated negative feedbacks that inhibited oxygen production by promoting anoxygenic photosynthesis and limiting the habitable space for eukaryotes, hence abating the long-term rise of oxygen and restricting the Ediacaran expansion of macroscopic oxygen-demanding animals. Using Hg isotopes, the authors find that repeated invasion of toxic, H2S-rich water into the marine photic zone of the Ediacaran ocean may have inhibited the rise of oxygen and delayed the expansion of early animals. [ABSTRACT FROM AUTHOR]

How did Chinese scientific intellectuals react to the dispute over evolutionary mechanisms during the period of the "eclipse of Darwinism"? This is my focal question. To answer it, I survey the attitudes of three groups of people toward the debate in the early decades of the twentieth century: Chinese paleontologists and their general embrace of the anti-Darwinian position, a group of non-specialists (or semi-specialists) and their assertion of a "revival of Lamarckism," and the American-trained Chinese biologists and their typical agnostic stance toward the antagonism between Darwinism and the mutation theory. Different concerns or motivations underlay these three different stances. There were also interesting attempts by biologists like Chen Zhen to exploit some recreational breeding traditions like goldfish breeding peculiar to China to participate in the dispute more directly. [ABSTRACT FROM AUTHOR]

Porcine coronavirus SADS-CoV has been identified from suckling piglets with severe diarrhea in southern China in 2017. The SADS-CoV genome shares ~95% identity to that of bat α-coronavirus HKU2, suggesting that SADS-CoV may have emerged from a natural reservoir in bats. Here we report the cryo-EM structures of HKU2 and SADS-CoV spike (S) glycoprotein trimers at 2.38 Å and 2.83 Å resolution, respectively. We systematically compare the domains of HKU2 spike with those of α-, β-, γ-, and δ-coronavirus spikes, showing that the S1 subunit N- and C-terminal domains of HKU2/SADS-CoV are ancestral domains in the evolution of coronavirus spike proteins. The connecting region after the fusion peptide in the S2 subunit of HKU2/SADS-CoV adopts a unique conformation. These results structurally demonstrate a close evolutionary relationship between HKU2/SADS-CoV and β-coronavirus spikes and provide insights into the evolution and cross-species transmission of coronaviruses. Several coronaviruses infecting humans and animals have emerged in recent years. Here, the authors provide structures of the spike proteins of the porcine coronavirus SADS-CoV and closely related bat coronavirus HKU2, providing insights into evolution of coronavirus spike proteins. [ABSTRACT FROM AUTHOR]

Seasonal cycle of China summer precipitation has significant impacts on its subseasonal predictability; yet current understanding of seasonal evolution of the intraseasonal variability (ISV) remains limited. Here, we show that the ISV of China summer precipitation features a distinct three-stage evolution during early summer, Meiyu season, and late summer. There are two common leading ISV modes: a uniform mode (UM) over southeastern China and a dipole mode (DM) between coastal southeastern China and mid-lower reaches of the Yangtze River Basin, which occur during all three stages with a dominant period of 8–15 days in the early and late summers and 8–25 days during Meiyu season. These two modes show southward propagation in early summer, but they are independent from each other in the other two stages. In early summer, both UM and DM are only related to mid-latitude wave train, and no preceding signal is found in the tropics due to the weak western North Pacific (WNP) monsoon trough. In contrast, during the Meiyu season and late summer, preceding tropical signals are observed when the WNP monsoon trough becomes strong. In the late summer, the effect of mid-latitude wave train is weak as the westerly jet-induced wave guide is far away from southeastern China. An improved subseasonal prediction system is expected to be benefited from consideration of the seasonal evolution of China summer precipitation ISV. [ABSTRACT FROM AUTHOR]

In order to choose the appropriate time for the dynamic reinforcement, the time effect of stress field evolution of the surrounding rock was first analyzed in this study. Then the deep soft rock roadway in Xinhu Coal Mine, China was taken as a typical example with regard to how the rheology-affected stress field of the surrounding rock evolved. The calculation algorithm of stress field evolution was given together with the corresponding program developed. Calculation results showed that the peak point of the surrounding rock in the early phase moved faster, where the turn appeared on the 60th day when the peak point lied 6.96 m away from the center of the roadway. Then the peak point moved at a slower pace, and finally, on the 124.8th day, the stress peak point was basically stabilized 7.21 m away from the center. In this way, the appropriate dynamically-reinforced supporting time of the No. 2 North rail-crosscut in Xinhu Mine was determined as 60 days after the primary support. In addition, a dynamic reinforcement technical plan was developed. The primary supporting system was bolt + W-shaped strip + diamond mesh + shallow hole grouting bolt + cable + shotcrete, and the reinforcement support system was bolt + M4 strip + diamond mesh + grouting cable. In-situ observation showed that both the maximum deformation and its maximum velocity in the roof and both walls of the roadway were small. The results indicated that both the reinforced supporting time and the parameters are appropriate. [ABSTRACT FROM AUTHOR]

Accurate simulation and prediction of intense precipitation events require better understanding of their physical mechanisms. This study uses Yaan—a place with regional maximum rainfall in central China—to investigate the cause and process of intense precipitation. Hourly rain gauge records and the new ERA5 reanalysis are used to characterize the evolution process of warm season intense regional rainfall events (RREs) in Yaan and its associated three-dimensional circulation. Results show that before the start of the Yaan intense RREs, moderate rainfall amount (frequency) appears northeast of the key region. The rainfall then moves southward in the following several hours along the eastern periphery of the Tibetan Plateau where it reaches peak. It then moves to and end up in the south and southeast Sichuan Basin. The progression of the RREs is found to be associated with a counter-clockwise rotation of anomalous surface winds associated with a developing mesoscale surface low-pressure center, which is further associated with the southeastward progression of a large-scale synoptic scale wave. The easterly phase of the winds in the counter-clockwise rotation causes upslope motion perpendicularly toward the terrain that leads to maximum rainfall. The findings illustrate how large-scale circulations, mesoscale systems, and specific topographic features interact to create the RREs evolution in Yaan. [ABSTRACT FROM AUTHOR]

Eco-efficiency plays a significant role in expressing how efficient the economic activity consumes nature's goods and services. To accurately measure eco-efficiency, the method slack-based measure modified three-stage data envelopment analysis (DEA) is adopted to evaluate environmental conditions in China's 30 provinces from year 2004 to 2016. This study treats carbon emissions and three industrials wastes as undesirable outputs and excludes the influences from external environment and random errors when make adjustments. Based on the results, this study makes the following conclusions: Firstly, industrial structure, trade openness, and population have negative effects on eco-efficiency while technology investment, urbanization process, foreign direct investment, and fiscal decentralization have positive effects on eco-efficiency. Secondly, the eco-efficiency for most provinces after adjusted is lower than the pre-adjusted, which indicates the overestimation in eco-efficiency when using traditional approaches. Thirdly, the eco-efficiency in China showed a clear geographical step distribution, with the highest eco-efficiency in the east area, followed by the central, northwest, and southwest regions. [ABSTRACT FROM AUTHOR]

Surrounding rock control is problematic at irregular fully-mechanized working faces of inclined seams. This study investigated the evolution of mining-induced stress at a variable-length working face under different coal seam inclination angles by using FLAC3D software to establish an experimental model based on the occurrence conditions of the inclined seam and the layout of fully-mechanized working face in the western district of Pan'er mine in China. Analysis of the simulation data was used to determine the stress evolution of working face in the strike and dip directions under different dip angle conditions and reveal the relationship between mining stress evolution and coal seam inclination. Comparative analysis of the formation and evolution of mining-induced stress before and after the roadway connection was used to determine the mechanisms behind mining-induced stress evolution in the short face to long face connection process and to reveal asymmetrical differences in the mining-induced stress evolution of the upper, middle and lower parts of the coal seam along the dip direction. Based on the relationship between supports and surrounding rock, the structure of hydraulic powered supports, the entry arrangement and supporting characteristics, control methods to ensure the stability of surrounding rock are proposed such as a metal mesh above hydraulic powered supports and reinforcement at the junction. These measures are effective for preventing partial roof fall and rib spalling, loss of support stability and stress concentration at connecting entry and for achieving safe and efficient mining of irregular working faces in thick inclined seams. [ABSTRACT FROM AUTHOR]

Two case studies were conducted in the Shennan mining area of Shaanxi Province, China to evaluate the surrounding rock deformation and stress evolution in pre-driven longwall recovery rooms. These studies mainly monitored the surrounding rock deformation and coal pillar stress in the recovery rooms of the N1206 panel of 2−2 coal seam at Ningtiaota Coal Mine and the 15205 panel of 5−2 coal seam at Hongliulin Coal Mine. The monitoring results showed that the surrounding rock deformation of the main recovery room and the coal pillar stress in the N1206 and 15205 panels began to increase significantly when the face was 36 m and 42 m away from the terminal line, respectively. After the face entered the main recovery room, the maximum roof-to-floor convergence in the N1206 and 15205 panels was 348.03 mm and 771.24 mm, respectively, and the coal pillar stresses increased more than 5 MPa and 7 MPa, respectively. In addition, analysis of the periodic weighting data showed that the main roof break position of the N1206 and 15205 panels after the longwall face entered the main recovery room was − 3.8 m and − 8.2 m, respectively. This research shows that when the main roof breaks above the coal pillar, the surrounding rock deformation of the main recovery room and the coal pillar stress increase sharply. The last weighting is the key factor affecting the stability of the main recovery room and the coal pillar; main roof breaks at disadvantageous positions are the main cause of the support crushing accidents. [ABSTRACT FROM AUTHOR]

Fossil cyprinids from the upper part of the upper Eocene Youganwo Formation of Maoming, Guangdong, China were first studied in 1957 by Liu, who referred the only specimen to the genus Cyprinus as a new species, C. maomingensis. And this was suggested as one of the earliest records for fossil cyprinids. Unfortunately, this specimen is poorly preserved and reveals no more morphological information than its serrated last unbranched dorsal and anal fin rays. Recently, some new specimens were unearthed from the same locality, where C. maomingensis was discovered. In addition to the serrated dorsal and anal fin rays, these new materials also show that the pattern and shape of their pharyngeal teeth obviously differ from that of Cyprinus but resemble that of Procypris. However, its number of the branched dorsal fin rays and number of vertebrae are much less than that in Procypris. Morphologically, these specimens are closer to Procypris than to Cyprinus. This is the first report of fossil Procypris-like fish, and it implies that Procypris-like fish is an early member of the Tribe Cyprinini sensu stricto ( sensu Yang et al., 2010) and the origin of this group can be traced back at least to the late Eocene. [ABSTRACT FROM AUTHOR]

The North China Plain (NCP) is one of the global hotspots of groundwater depletion, groundwater is almost the only source of water for agricultural, industrial and drinking water in this region. After long-term's over-exploitation of deep groundwater, there appeared several deep groundwater depression cones, such as Cangzhou cone, Dezhou cone, Hengshui cone, Tianjin cone, etc., in which the Cangzhou cone is one of the typical cones for its special geography and hydrogeology conditions. In this study, the authors intended to analyze the evolution characteristics and influence factors of deep groundwater depression cone in Cangzhou region, especially the No. III aquifer depression cone, which is the main exploitation zone in this region. Analysis of the evolution of the groundwater depression cone of the No. III aquifer group in Cangzhou region showed that this process can be divided into four stages, namely, development, stable development, rapid expansion, and gradual recovery. The shape and evolution characteristics of the depression cone at different stages are described by analyzing the evolution of the −30, −40, and −50 contours of the groundwater table, for example the closed area of water table contour of −50 m has been enlarged from 95 km in 1985 to 6 528.5 km in 2005. The dominant factors that affect the evolution characteristics at different stages are proposed. The results showed that relatively long dry periods with less precipitation, special geological and hydrogeological conditions, and sharply increased water consumption for industrial and agricultural development are the main factors that cause the formation of deep groundwater depression cones. Meanwhile, an environmental response against groundwater exploitation is presented, and rational solutions are suggested to avert water crisis. [ABSTRACT FROM AUTHOR]

Rubella remains a significant burden in mainland China. In this report, 667 viruses collected in 24 of 31 provinces of mainland China during 2010-2012 were sequenced and analyzed, significantly extending previous reports on limited numbers of viruses collected before 2010. Only viruses of genotypes 1E and 2B were found. Genotype 1E viruses were found in all 24 provinces. Genotype 1E viruses were likely introduced into mainland China around 1997 and endemic transmission of primarily one lineage became established. Viruses reported here from 2010-2012 are largely in a single cluster within this lineage. Genotype 2B viruses were rarely detected in China prior to 2010. This report documents a previously undetected 2B lineage, which likely became endemic in eastern provinces of China between 2010 and 2012. Bayesian analyses were performed to estimate the evolutionary rates and dates of appearance of the genotype 1E and 2B viral linages in China. A skyline plot of viral population diversity did not provide evidence of reduction of diversity as a result of vaccination, but should be useful as a baseline for such reductions as vaccination programs for rubella become widespread in mainland China. [ABSTRACT FROM AUTHOR]