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Clay minerals have great potentials in pinpointing sediment provenance for large depositional systems. However, source identification using clay minerals for small floodplain lakes is not well known. Situated in the North China Plain, the Dongping Lake receives sediments from both the Yellow River and the Dawen River, thereby representing an ideal site for testing the utility of this method. Here we use clay minerals in conjunction with the Bayesian end-member modeling analysis (BEMMA) to quantify the riverine contribution to modern sediments in the Dongping Lake. Results showed that modern sediments of the Dongping Lake are characterized by four primary clay minerals: illite, smectite, kaolinite, and chlorite, with average contents of 60.53%, 11.37%, 12.70%, and 15.40%, respectively. Clay minerals in modern sediments of the Dongping Lake are mainly delivered by the Yellow River, accounting for approximately 58.99–72.33%; whereas those originating from the Dawen River only account for 27.67–41.01%. It is also found that clay mineral from these rivers have a marked spatial variability. For example, source materials from the Yellow River are widely distributed across the lake, while those from the Dawen River only occur at the estuary of the river and slightly spread out in all directions under the action of water flow. [ABSTRACT FROM AUTHOR]

Background: Nonalcoholic fatty liver disease (NAFLD) is a common component of chronic liver disease. Total bile acid (TBA) may influence the NAFLD progression through its signaling pathways. We attempted to find out if there is a correlation between TBA and NAFLD. Methods: 427,507 subjects were enrolled in health examinations conducted by The First Affiliated Hospital of Wenzhou Medical University. Among them, only 67616 met the inclusion criteria. Demographic, clinical, and laboratory data were gathered from all subjects. We used multivariate logistic regression model to find the correlation between serum TBA and NAFLD after adjusting for acknowledged risk factors for NAFLD. Results: A negative correlation was found between the TBA and NAFLD after adjusting for confounders in the multivariate logistic regression model (OR: 0.80; 95% CI: 0.72, 0.88, P < 0.001). After subgroup analysis, we found the interaction between NAFLD and diabetes was significant (P = 0.043). In patients with NAFLD without diabetes, TBA showed a protective effect in NAFLD (OR: 0.75; 95% CI: 0.67, 0.85). Conclusion: TBA is protective for NAFLD, but not in patients with NAFLD and diabetes. Further studies are urgently required to completely explore the underlying mechanisms of TBA in the pathogenesis of NAFLD. [ABSTRACT FROM AUTHOR]

Soil moisture is an essential climate variable (ECV) concerned widely. Due to its high spatial variability, it is costly to measure soil moisture at tens of kilometers scale. In this study, a ten-year (2002–2011) daily soil moisture dataset at 0.25° spatial resolution for Mainland China was produced through assimilating the Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) brightness temperature (TB) data into a land surface model (LSM). The obtained soil moisture data was evaluated against soil moisture-measuring networks deployed in two wet areas and one dry area of the Tibetan Plateau. The results show that for the wet areas the accuracy of the soil moisture product obtained from the assimilation is considerably higher than that of both AMSR-E official soil moisture products and land surface simulation results, and for the dry area their accuracy is comparable to each other. The spatial pattern of the soil moisture from the new product is consistent with that of soil porosity from an independent survey-based dataset, further confirming the credibility of the new product. According to this product, the transition regions in China show stronger seasonal variation of soil moisture than dry and wet regions, and drier regions have stronger inter-annual variability of soil moisture than wetter regions, particularly during transitional seasons (spring and autumn). The soil moisture product is accessible at the National Tibetan Plateau Data Center. [ABSTRACT FROM AUTHOR]

Although prior studies have proposed some smart city index systems, they primarily focus on generic indicators connected to urban development and fail to reflect the properties of intelligence. To fill this gap, we develop a new index system involving three dimensions of digital infrastructure, smart living, and digital economy. Moreover, compared with studies that use subjective weighting methods to rank the smartness of cities, we combine the Shannon entropy weighting method with three multi-criteria decision-making (MCDM) methods to show the objectiveness of the evaluation process. Through analyzing the quantitative data from nine cities in the Pearl River Delta (PRD) region in China, we find that digital infrastructure is the most important first-level indicator, accounting for 46.92%, followed by the digital economy and smart life accounting for 32.48% and 20.60% respectively. More importantly, when the nine cities in the PRD region are ranked by three MCDM methods, the correlation between the results is over 90%, thus proving robustness. We contribute to the current smart city literature by enriching the components of the smart city index system, as well as evaluation methods. Our findings also guide decision-makers in formulating more targeted smart city construction plans. • Develop a new smart city index system involving three dimensions of digital infrastructure, smart living, and digital economy • Use three multi-criteria decision-making (MCDM) methods to rank the smartness of cities • Data were gathered from online platforms in the Pearl River Delta Region, China. • The correlation between the results from different MCDM methods is >90%. • The practical implications are highlighted. [ABSTRACT FROM AUTHOR]

Daytime land surface temperatures in arid and semiarid regions are typically not well simulated in current land surface models (LSMs). This study first evaluates the importance of parameterizing the thermal roughness length ( z0 h) to model the surface temperature ( Tsfc) and turbulent sensible heat flux ( H) in arid regions. Six schemes for z0 h are implemented into the Noah LSM, revealing the high sensitivity of the simulations to its parameterization. Comparisons are then performed between the original Noah LSM and a revised version with a novel z0 h scheme against observations at four arid or semiarid sites, including one in Arizona and three in western China. The land they cover is sparse grass or bare soil. The results indicate that the original Noah LSM significantly underestimates Tsfc and overestimates H in the daytime, whereas the revised model can simulate well both Tsfc and H simultaneously. The improved version benefits from the successful modeling of the diurnal variation of z0 h, which the original model cannot produce. [ABSTRACT FROM AUTHOR]

The definition of property rights, as an interactive process between the parties concerned to establish or change a contract of rights, is without doubt an important social activity in the history of economic life. Ever since the mid 1990s, certain developments from the transformation of township collective enterprises indicate that community collective property rights mainly comprise a property right that is socially contractual instead of market contractual. This kind of social contract is neither some kind of consciously designed system nor a natural expression of social relations. Instead, it is the outcome of relations and specific coordinated actions that represents a harmonious social order. Under an imperfect market contract, it might be possible to handle and solve cooperation issues and property rights conflicts within a community in an informal manner and therefore this could play a role in defining and maintaining the order of community property rights. However when there are drastic changes in the institutional environment, such a role for the social contract is very limited. Today, when institutional transformations still need to be backed by administrative force, severels' harmful consequences for sustainable community development would result if the informal rules of social contract were merely replaced with some institutional design that did not take into consideration the extension or replacement of the social contract. [ABSTRACT FROM AUTHOR]

Introduction: Rhegmatogenous retinal detachment (RRD) is one of the most common fundus diseases. Many rural areas of China have few ophthalmologists, and ophthalmologic ultrasound examination is of great significance for remote diagnosis of RRD. Therefore, this study aimed to develop and evaluate a deep learning (DL) model, to be used for automated RRD diagnosis based on ophthalmologic ultrasound images, in order to support timely diagnosis of RRD in rural and remote areas. Methods: A total of 6,000 ophthalmologic ultrasound images from 1,645 participants were used to train and verify the DL model. A total of 5,000 images were used for training and validating DL models, and an independent testing set of 1,000 images was used to test the performance of eight DL models trained using four different DL model architectures (fully connected neural network, LeNet5, AlexNet, and VGG16) and two preprocessing techniques (original, original image augmented). Receiver operating characteristic (ROC) curves were used to analyze their performance. Heatmaps were generated to visualize the process of the best DL model in the identification of RRD. Finally, five ophthalmologists were invited to diagnose RRD independently on the same test set of 1,000 images for performance comparison with the best DL model. Results: The best DL model for identifying RRD achieved an area under the ROC curve (AUC) of 0.998 with a sensitivity and specificity of 99.2% and 99.8%, respectively. The best preprocessing method in each model architecture was the application of original image augmentation (average AUC = 0.982). The best model architecture in each preprocessing method was VGG16 (average AUC = 0.998). Conclusion: The best DL model determined in this study has higher accuracy, sensitivity, and specificity than the ophthalmologists' diagnosis in identifying RRD based on ophthalmologic ultrasound images. This model may provide support for timely diagnosis in locations without access to ophthalmologic care. [ABSTRACT FROM AUTHOR]

Lacustrine sediment played important roles in migration and transformation of its water soluble organic matter (WSOM), and the source and composition of WSOM would affect water trophic status and the fate of pollutants. However, we know little about the pathway of WSOM transformation and its driving bacterial communities in lacustrine sediment. In the present study, we investigated the spatial distribution patterns of sediment WSOM and its fluorescent fractions across Lake Chaohu using fluorescence spectroscopy, and explored WSOM compositional structure through our proposed calculated ratios. In addition, we also analyzed sediment bacterial community using Illumina sequencing technology, and probed the possible pathway of sediment WSOM transformation under the mediate of indigenous bacteria. Our results showed that the inflowing rivers affected the spatial distribution patterns of WSOM and its five fractions (including tyrosine-, tryptophan-, fulvic acid-, humic acid-like substances and soluble microbial productions), and sediment WSOM originated from fresh algae detritus or bacterial sources. In parallel, we also found that Proteobacteria (mainly γ-Proteobacteria and δ-Proteobacteria), Firmicutes (mainly Bacilli), Chloroflexi, Acidobacteria, Planctomycetes and Actinobacteria dominate sediment bacterial community. Furthermore, these dominant bacteria triggered sediment WSOM transformation, specifically, the humic acid-like substances could be converted into fulvic acid-like substances, and further degraded into aromatic protein-like and SMP substances. In addition, our proposed ratios (P-L:H-L, Ar-P:SMP and H-L ratio), as supplementary tool, were effective to reveal WSOM composition structure. These results figured out possible pathway of WSOM transformation, and revealed its microbial mechanism in lacustrine sediment. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The present analysis has revealed that both the altimetry and tide gauge records show a prominent sea level rise from 1993 to 2016 in the coastal seas east of China, including Bohai, Yellow Sea, and East China Sea (BYECS). The regional mean sea level rise rate for the BYECS continental shelf area is ~ 3.2 mm/year, which is close to the global mean (2.9 mm/year). Besides the rising trend, the BYECS sea level anomaly (SLA) also shows obvious interannual and decadal oscillation. It is found that the mid-latitude westerlies, rather than the steric height variability, are responsible for these oscillations. By analyzing the 67-year (1950–2016) hindcast outputs from an eddy-resolving ocean general circulation model, a 14.2 years decadal period is found to dominate the BYECS SLA variability, and the decadal oscillation is positively correlated with the North Pacific Gyre Oscillation (NPGO). The composite analysis and causality analysis demonstrate that during the positive phase of the NPGO, the mid-latitude westerlies decrease and a positive wind stress curl anomaly at the same latitude of the East China Sea's Kuroshio occurs to the south of the westerlies. Consequently, the Kuroshio Current volume transport and sea surface height difference between the two sides of the Kuroshio decrease, that is, the sea level in the BYECS rises. [ABSTRACT FROM AUTHOR]

Background: China has stepped into an era of aging society, where the impending considerable economic burden attributed to high prevalence of dementia in the elderly appears to be one of the most important health and social issues to deal with for the country. However, population-based quantification and projections for the economic burden of dementia in China are lacking for further health action and policy making. Objective: To estimate and predict the costs of managing dementia in the elderly population aged 60 and above from 2010 to 2050 in China. Methods: Data were collected from a six-province study (n = 7072) and other multiple sources for calculation of the economic burden of dementia. With the convincing data from published studies, we quantified and projected the costs attributed to dementia in China from 2010 to 2050. Results: The national cost of dementia in 2010 was estimated to be US$22.8 billion by the opportunity cost method and US$26.4 billion by the proxy method. In 2050, the costs would increase to US$372.3 billion by the opportunity cost method and US$430.6 billion by the proxy method, consuming 0.53% and 0.61% of China's total GDP, respectively. A series of sensitivity analyses showed that the changes in the proportions of informal caregiving led to the most robust changes in the total burden of care for dementia in China. Conclusion: Dementia represents an enormous burden on China's population health and economy. Due to the changes in policies and population structure, policymakers should give priority to dementia care. [ABSTRACT FROM AUTHOR]

The Yellow River floodplain represents a fertile landmass that contributes significantly to human welfare and thus has been colloquially known as the birthplace of Chinese civilization. The sediment-laden nature of the Yellow River gave rise to a super-elevated channel belt, which is prone to failure particularly in the summer months when excessive precipitation occurs, resulting in cataclysmic floods traditionally regarded as "China's Sorrow." Therefore, a deeper understanding of levee breach frequency in this area is especially important for the assessment of socio-economic risk of levee breaches associated with future climate changes. To better understand the nature, evolution, and driving mechanisms of levee breaches on the lower Yellow River, it is necessary to place the instrumental data within a longer time framework. Here, we retrieve past information about levee breaches on the lower Yellow River since AD 11 from various documentary sources such as official histories of China. We evaluated each line of descriptions and narratives about the location, timing, and nature of each event in these documents, ending up with a detailed timeline of levee breaches on the lower Yellow River during the last 2000 years on an annual time scale. Our results reveal remarkable variations in the frequency of levee breaches superimposed on a long-term increasing trend. In addition to climate changes, the iterative embankment-siltation-breaching process caused a feedback: more breaches result in much more channel siltation, which in turn leads to even more breaches. The enhanced farming in the Loess Plateau played a pivotal role in the formation and operation of this positive feedback. Our findings may not only help improve the assessment of socio-economic risk of levee breaches associated with future climate changes, but also provide consulting information for hydraulic engineering and infrastructural designs in the lower Yellow river area. [ABSTRACT FROM AUTHOR]

The WRKY family of transcription factors plays important roles in plant growth and responses to biotic and abiotic stresses. Ammopiptanthus nanus, the only evergreen broadleaf shrub endemic to the desert and semi-desert regions of northwestern China, is highly tolerant to various stresses. However, a systematic study of WRKY proteins in A. nanus has not been reported. In the present study, we identified 63 WRKY genes in the A. nanus genome. Based on the conserved WRKY domains, zinc finger structures, and phylogenetic relationships in their encoded proteins, we classified these genes into four groups (group I–IV) and several subgroups (subgroup IIa–IIe). Conserved motif analysis showed that all motifs except those within the WRKY domains had a subfamily-specific distribution. Expression analysis revealed that the AnWRKY genes had distinct expression patterns, with some being more responsive to herbivory and drought stresses than others. Based on the results of our current study, we speculate that AnWRKY40 and AnWRKY48 are positive regulators of the plant's response to drought and herbivory stresses, respectively. Our results indicate that AnWRKY genes contribute to the ability of A. nanus plants to withstand harsh, dry conditions. [ABSTRACT FROM AUTHOR]

PM 2.5 and home and community-based services (HCBSs) had been shown to affect cognition, but the evidence on their joint effects was limited. Aimed to study the joint effects of HCBSs and PM 2.5 on cognition, we utilized the follow-up data of participants in the Chinese Longitudinal Health Longevity Survey (CLHLS) who were 65 years of age or older and had normal cognitive function at baseline for the 2008–2018, 2011–2018, and 2014–2018 waves. 16,954, 9,765, and 7192 participants from each of these three waves were initially recruited, respectively. The PM 2.5 concentration data of each province in China from 2008 to 2018 was obtained from the Atmospheric Composition Analysis Group. Participants were asked what kind of HCBSs were available in their community. The cognitive status of the participants was evaluated by the Chinese version of Mini-Mental State Examination (CMMSE). We applied the Cox proportional hazard regression model to investigate the joint effects of HCBSs and PM 2.5 on cognition and further stratified the analysis according to HCBSs. Hazard ratio (HR) and 95% confidence interval (95% CI) were calculated based on Cox models. During a median follow-up period of 5.2 years, 911 (8.8%) participants with normal baseline cognitive function developed cognitive impairment. Compared to participants without HCBSs and exposed to the highest level of PM 2.5 , those with HCBSs and exposed to the lowest level of PM 2.5 had a significantly reduced risk of developing cognitive impairment (HR = 0.428, 95% CI: 0.303–0.605). The results from the stratified analysis revealed that the detrimental effect of PM 2.5 on cognition was more pronounced in participants without HCBSs (HR = 3.44, 95% CI: 2.18–5.41) compared with those with HCBSs (HR = 1.42, 95% CI: 0.77–2.61). HCBSs may attenuate the harmful impact of PM 2.5 on cognitive status in the elderly Chinese and the government should further promote the application of HCBSs. [Display omitted] • PM 2.5 can impair the cognitive function. • Home and community-based services are protective factors for cognition. • Home and community-based services alters the association between PM 2.5 and cognition. [ABSTRACT FROM AUTHOR]

Lacustrine rift basins in Eastern China possess large amounts of petroleum, especially the shale gas and tight sand gas in deep formations, where "sweet spots" are closely related to organic-rich shale intervals. However, the OM enrichment of deep formation shale in lacustrine rift basins and the main controlling factors have not been well-researched in previous studies. The organic matter (OM) enrichment is mainly controlled by the OM input, preservation, and/or dilution. The shales deposited in deep formations of Songliao Basin, including the Jurassic Huoshiling (J 3 h), Cretaceous Shahezi (K 1 sh), and Yingcheng (K 1 yc) formations, are evaluated as fair to excellent source rocks. Taking the shales as an example, the characters and impact of input, preservation, and dilution on OM enrichment in shales are discussed by utilizing the parameters of element concentrations and biomarkers. Results show that the OM sources are mixed sources of aquatic microorganisms and higher plant materials, and the higher plant materials are dominant. The bio-productivity were moderate to high. The paleoclimate was mainly the cold and semi-humid to semi-arid. The lake salinity was fresh-to brackish-water. The redox conditions were sub-reducing to sub-oxidizing. The dilution degree in Yingcheng was the strongest, followed by the Shahezi and Huoshiling. Consequently, the OM enrichment in the J 3 h shale was called moderate bio-productivity and preservation model; the OM enrichment in the K 1 sh shale was called high bio-productivity and preservation model; the OM enrichment in the K 1 yc shale was named high dilution model. This study not only improves the model of OM enrichment but also provide some information for the research of "Deep time" in the Cretaceous of Songliao Basin, guiding the prediction of organic-rich shale distribution in lacustrine rift basin. • Fair to excellent hydrocarbon generation potential. • Organic matter origins are mainly a mixture of aquatic microorganisms and terrestrial higher plants. • Arid and cold paleoclimate and fresh- and brackish-water. • Reducing to sub-reducing, sub-reducing to oxidizing, and sub-reducing to sub-oxidizing conditions. • Moderate bio-productivity and preservation model, high bio-productivity and preservation model, high dilution model. [ABSTRACT FROM AUTHOR]

Summary: Alpine meadow soil is an important ecosystem component of the Qinghai-Tibetan Plateau. However, the alpine meadow soil is undergoing serious degradation mainly due to global climate change, overgrazing, human activities and rodents. In this paper, spatial sequencing was chosen over time succession sequencing to study the changes of soil hydraulic properties under different degrees of alpine meadow degradation. Soil saturated hydraulic conductivity (Ks) and Gardner α both at the surface and at 40–50cm depth were investigated in the field using tension infiltrometers. Soil physical and chemical properties, together with the root index at 0–10cm and 40–50cm soil layer depths were also analyzed. Pearson correlations were adopted to study the relationships among the investigated factors and principal component analysis was performed to identify the dominant factor. Results show that with increasing degree of degradation, soil sand content increased while soil Ks and Gardner α as well as soil clay content, soil porosity decreased in the 0–10cm soil layers, and organic matter and root gravimetric density decreased in both the 0–10cm and 40–50cm soil layers. However, soil moisture showed no significant changes with increasing degradation. With decreasing pressure head, soil unsaturated hydraulic conductivity reduced more slowly under degraded conditions than non-degraded conditions. Soil Ks and Gardner α were significantly correlated (P =0.01) with bulk density, soil porosity, soil organic matter and root gravimetric density. Among these, soil porosity is the dominant factor explaining about 90% of the variability in total infiltration flow. Under non-degraded conditions, the infiltration flow principally depended on the presence of macropores. With increasing degree of degradation, soil macropores quickly changed to mesopores or micropores. The proportion of total infiltration flow through macropores and mesopores significantly decreased with the most substantial decrease observed for the macropores in the 0–10cm soil layer. The substantial decrease of macropores caused a cut in soil moisture and hydraulic conductivity. This study improves the understanding and prediction of alpine meadow soil and ecosystem changes and provides guidelines for improving water flow modeling under the background of global climate change over the Qinghai-Tibetan Plateau and similar regions. [Copyright &y& Elsevier]

We present a field investigation over a melting valley glacier on the Tibetan Plateau. In the ablation zone, aerodynamic roughness lengths ( z) vary on the order of 10-10 m, whose evolution corresponds to three melt phases with distinct surface cover and moisture exchange: snow (sublimation/evaporation), bare ice (deposition/condensation), and ice hummocks (sublimation/evaporation). Bowen-ratio similarity is validated in the stably stratified katabatic winds, which suggests a useful means for data quality check. A roughness sublayer is regarded as irrelevant to the present ablation season, because selected characteristics of scalar turbulence over smooth snow are quite similar to those over hummocky ice. We evaluate three parametrizations of the scalar roughness lengths ( z for temperature and z for humidity), viz. key factors for the accurate estimation of sensible heat and latent heat fluxes using the bulk aerodynamic method. The first approach is based on surface-renewal models and has been widely applied in glaciated areas; the second has never received application over an ice/snow surface, despite its validity in (semi-)arid regions; the third, a derivative of the first, is proposed for use specifically over rough ice defined as z > 10 m or so. This empirical z threshold value is deemed of general relevance to glaciated areas (e.g. ice sheet/cap and valley/outlet glaciers), above which the first approach gives notably underestimated z. The first and the third approaches tend to underestimate and overestimate turbulent heat/moisture exchange, respectively, frequently leading to relative errors higher than 30%. Comparatively, the second approach produces fairly low errors in energy flux estimates both in individual melt phases and over the whole ablation season; it thus emerges as a practically useful choice to parametrize z in glaciated areas. Moreover, we find all three candidate parametrizations unable to predict diurnal variations in the excess resistances to humidity transfer, thus encouraging more efforts for improvement. [ABSTRACT FROM AUTHOR]

Analysis of morphological properties in the San men Gorges region of the Yellow River shows that four river terraces have been developed at the entrance to the gorges. Commonly, thick aeolian loess-paleosol sequence was deposited on the terraces, which makes it easy to date the terraces. The dating of paleomagnetic, loess-paleosol sequence matching and thermoluminescence show that terraces T2, T3 and T4 were formed 0.129 Ma, 0.625 Ma and 0.865 Ma ago, respectively. The formation of these terraces in this region indicates that the Yellow River has experienced four intensive downcutting events during the last 0.9 Ma. The Yellow River cut through the Sanmen Gorges and inpoured into the East China Sea no later than 0.865 Ma. [ABSTRACT FROM AUTHOR]

• We estimated the time to the most recent common ancestor (TMRCA) and evolutionary rate of SARS-CoV-2 to be 12 November 2019 (95% BCI: 11 October 2019 and 09 December 2019) and 9.90 × 10-4 substitutions per site per year (95% BCI: 6.29 × 10-4–1.35 × 10-3), respectively. • Our results emphasize the importance of using phylogenetic and phylodynamic analyses to provide insights into the roles of various interventions to limit the spread of SARS-CoV-2 in China and beyond. • Understanding epidemic dynamics of SARS-CoV-2 in real time is increasingly important for guiding prevention efforts. To investigate the evolutionary and epidemiological dynamics of the current COVID-19 outbreak, a total of 112 genomes of SARS-CoV-2 strains sampled from China and 12 other countries with sampling dates between 24 December 2019 and 9 February 2020 were analyzed. We performed phylogenetic, split network, likelihood-mapping, model comparison, and phylodynamic analyses of the genomes. Based on Bayesian time-scaled phylogenetic analysis with the best-fitting combination models, we estimated the time to the most recent common ancestor (TMRCA) and evolutionary rate of SARS-CoV-2 to be 12 November 2019 (95 % BCI: 11 October 2019 and 09 December 2019) and 9.90 × 10−4 substitutions per site per year (95 % BCI: 6.29 × 10−4–1.35 × 10−3), respectively. Notably, the very low R e estimates of SARS-CoV-2 during the recent sampling period may be the result of the successful control of the pandemic in China due to extreme societal lockdown efforts. Our results emphasize the importance of using phylodynamic analyses to provide insights into the roles of various interventions to limit the spread of SARS-CoV-2 in China and beyond. [ABSTRACT FROM AUTHOR]

The Songliao Basin is the most productive petroliferous lacustrine basin in NE China, and numerous large gas fields with large proven reserves occur in its deep formations. However, considerable challenges remain: (1) the origins and genetic types of the natural gases are controversial; (2) the gas-source correlations are poorly studied; and (3) the migration distance is vague. In this study, these problems are addressed by the study of the gas compositions, light hydrocarbons, and stable hydrogen and carbon isotopes. The gases are predominantly of organic and thermogenic origins. The Huoshiling (J3h) and Shahezi (K1sh) gases are mainly mixtures of coal-derived and oil-associated gases and the mixed-sources of primary kerogen degradation and secondary oil cracking, while the Yingcheng (K1yc) gases are mainly coal-derived gases and predominantly derived from primary kerogen degradation. The gases in different sags are derived from the source rocks developed in the same sags where the gases accumulated, characterized by the proximal-source accumulation. Vertically, the gases in the J3h and K1sh are predominantly sourced by the proximal J3h and K1sh mudstones, while the gases in the K1yc are mainly derived from either the J3h or the K1sh source rocks, suggesting the gas migration with short distances. [ABSTRACT FROM AUTHOR]

The superimposed foreland basins mainly develop in central-western China, namely the Himalayan foreland basins superimposed on the Indo-China foreland basins. Previous research on hydrocarbon migration predominantly focused on the typical foreland basins and the fore-deep depression of superimposed foreland basins. As a result of multi-superimposition, large hydrocarbon potentials in the slope zones are evaluated, and the hydrocarbon migration shows significant differences with those in the typical foreland basins. Moreover, the hydrocarbon migration models in the slope zone of superimposed foreland basins are poor analyzed. The Chepaizi High in the South Junggar Basin, a typical slope of superimposed foreland basin, has been taken into consideration. Several points have been ascertained. 1) Multistage charging and readjustment events should be the predominant characters. 2) The combination of multi-type sand-bodies, multistage faults and unconformities have formed step- or "Z"-shaped migration pathways spatially. 3) Hydrocarbons migrated from the areas of high oil potential in the fore-deep depression to those of low oil potential in the slope. 4) The migration models of the J 1 b, K 1 q, N 1 s 1 , and N 1 s 2 have been established. Hydrocarbon reservoirs in the slope zones show the shallow accumulation from deep/distal sources with multiple reservoirs vertically and multi-charging and -readjustments chronologically. 5) The areas of (Wells SM3, C53-C90, and CF2), (Wells SM5, C80, and CF13), and (Wells K8, HG4, SM4, and CF2) can be the favorable targets for the J 1 b, K 1 q, and N 1 s, respectively. • Z-shaped and step-shaped composite hydrocarbon migration pathways. • High oil potential located in the fore-deep depression. • Hydrocarbons migrated from the fore-deep depression to the slope. • Multistage migration histories and multistage readjustments in the slope. • Hydrocarbon charged from deep sources and over long distances. [ABSTRACT FROM AUTHOR]