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The groundwater table in the piedmont plain was only about 1–2 m in depth in the 1950s and 1960s, but it lowered dramatically afterwards to about 25–27 m in depth (currently 21–23 m above sea level) due to overpumping of groundwater and drought in the region. This change has adversely affected the sustainable development and food supply of this important agricultural area. The groundwater table at Luancheng Experimental Station of the Chinese Academy of Sciences, located in the piedmont, dropped from 39.36 m in 1975 to 21.47 m above sea level in 1999, at an average rate of 0.72 m/year. Water balance components, such as daily rainfall, pan-evaporation, and evapotranspiration (by lysimeter after 1995) have been recorded since the 1970s, and they were used as variants to simulate monthly water table change based on a physically based statistical model. Groundwater samples were collected during the period 1998–2001, and tritium was measured in the laboratory to trace the groundwater flow from the Taihang Mountains to the piedmont. A reasonable exploitation rate of 150 mm/year was obtained from the model by assuming the annual water table is constant. The recharge and groundwater flow from the Taihang Mountains plays an important role in the water balance of the piedmont area, and it was estimated to be about 112.5 mm/year by using the variation of tritium with the depth, which followed a good exponential function. The simple water balance calculation indicated that the water table could recede at a rate of 0.8 m/year, which is close to the actual situation. [ABSTRACT FROM AUTHOR]

Reports that daily evapotranspiration from a winter wheat field on the North China Plain measured by large-scale weighing lysimeter was linearly related to that measured by the Bowen ratio energy balance (BREB) technique. Average of soil evaporation from the post-winter dormancy revival stage to the grain ripening stage; Amount of the net radiation flux Rn was used to warm soil on clear days during winter dormancy; During the revival stage, conductive heat flux G that also used most of the incoming Rn, but the ratio of latent heat flux uE to Rn that increased; Percentage of uE of Rn during the stem-extension stage; Increase of uE/Rn; Percentage of G;. Percentage of uE during the ripening stage; Evaporative fraction (EF) that can be expressed as a function of plant status and atmospheric boundary layer conditions; Relationship between EF and available energy under moderate air temperature and vapor pressure deficit conditions that was examined for five combinations of aerodynamic and canopy conductance; Theoretical relationship that indicates that EF should be highly correlated to soil water content; Correlation that has been difficult to identify under field conditions; Observation that there exists a threshold value of Rn m G, above which EF is less than 1?0, and that the threshold value is lower under soil-water deficit conditions than under abundant soil-water conditions.

Accurate flood event simulation and prediction, enabled by effective models and reliable data, are critical for mitigating the potential risk of flood disaster. This study aims to investigate the impacts of spatiotemporal resolutions of precipitation on flood event simulation in a large-scale catchment of China. We use high-spatiotemporal-resolution Integrated Multi-satellite Retrievals for Global Precipitation Measurement (IMERG) products and a gauge-based product as precipitation forcing for hydrologic simulation. Three hydrological models (HBV, SWAT and DHSVM) and a data-driven model (long short-term memory (LSTM) network) are utilized for flood event simulation. Two calibration strategies are carried out, one of which targets matching of the flood events, with peak discharge exceeding 8600 m 3 s -1 between January 2015 and December 2017, and the other one is the conventional strategy for matching the entire streamflow time series. The results indicate that the event-based calibration strategy improves the performance of flood event simulation compared with a conventional calibration strategy, except for DHSVM. Both hydrological models and LSTM yield better flood event simulation at a finer temporal resolution, especially in flood peak simulation. Furthermore, SWAT and DHSVM are less sensitive to the spatial resolutions of IMERG, while the performance of LSTM obtains improvement when degrading the spatial resolution of IMERG-L. Generally, LSTM outperforms the hydrological models in most flood events, which implies the usefulness of the deep learning algorithms for flood event simulation. [ABSTRACT FROM AUTHOR]

Compared with large enterprises, the development scale and organizational structure of small and medium-sized enterprises are insufficient, which brings certain limitations to the development of small and medium-sized enterprises in China. In order to promote the long-term development of small and medium-sized enterprises in the new era, it is necessary to require enterprise leaders to innovate marketing plans, strengthen risk management of enterprises, and enhance their strength in market competition. The market risk evaluation of small and medium sized enterprises (SMSEs) in the new era is a multiple-attribute decision-making (MADM). The IVIFSs are employed as the tool for portraying uncertain information during the market risk evaluation of SMSEs in the new era. In this paper, the interval-valued intuitionistic fuzzy (IVIF) Hamacher interactive power geometric (IVIFHIPG) technique is addressed based on IVIF Hamacher interactive weighted geometric (IVIFHIWG) technique and power geometric (PG) technique. Some properties of IVIFHIPG technique were addressed. Then, the IVIFHIPG technique is employed to manage MADM under IVIFSs. Finally, an example for market risk evaluation of SMSEs in the new era is employed to verify the IVIFHIPG technique. Thus, the main contributions of this paper are addressed: (1) the IVIFHIPG technique is addressed based on IVIFHIWG technique and PG technique; (2) the IVIFHIPG technique is came up with to manage the MADM under IVIFSs; (3) a numerical example for market risk evaluation of SMSEs in the new era has been came up with to show the IVIFHIPG technique; and (4) some comparative analysis is addressed to verify the I IVIFHIPG technique. [ABSTRACT FROM AUTHOR]

The measurement of groundwater exchange between neighboring regions is a critical topic in water resource management and can usually be achieved through a combination of field investigations and the use of groundwater flow models. In this study, we employed the water balance and Darcy's law methods, utilizing downscaled Gravity Recovery and Climate Experiment (GRACE) and GRACE-Follow On (GRACE-FO) data to assess groundwater exchange patterns in the Beijing-Tianjin-Hebei (BTH) region of China. Additionally, we determined the contributions of human activities and climate factors to the observed variations via residual analysis. The results revealed a consistent decrease in groundwater storage in the study area since 2008, especially in the spring and summer months. The groundwater exchange rates calculated by 1° and 0.05° groundwater storage anomalies (GWSAs) were basically consistent, and the downscaled GWSAs could better reflect the small-scale groundwater exchange characteristics. The groundwater exchange rate showed a decreasing trend from the Piedmont plain to the coastal areas. A notable trend of declining groundwater exchange between the Taihang Mountains and Piedmont plains was observed, and the downward trend gradually intensified from north to south between 2003 and 2007. After 2008, there was an increasing trend, and coastal areas exhibited the smallest amount of groundwater exchange. Human activities emerged as the predominant factor accounting for more than 90.9% of the overall reduction in groundwater storage, while climate change imposed a minimal influence on groundwater storage variations. The insights obtained in this study hold significant implications for groundwater resource planning and management in the region. [ABSTRACT FROM AUTHOR]

The groundwater environment in low-lying coastal regions is significantly impacted by global sea-level fluctuation. In Laizhou Bay, three large-scale transgressions have occurred since the late Pleistocene, resulting in the transformation of ancient seawater into brine. This brine has become a major contributor to groundwater salinity in the area. This study establishes a correlation between groundwater occurrence and paleoclimate changes in Laizhou Bay using borehole sediment data. The source and mechanism of groundwater salinity are analyzed based on sediment pore water characteristics and hydrogen and oxygen isotopes. The study reveals that the stratigraphic structures in the area consist of four layers: a Holocene transgressive layer, a continental confining bed from the late Pleistocene, a Cangzhou transgressive layer from the late Pleistocene, and a fluvial aquifer from the middle Pleistocene. All aquifers in the study area have been infiltrated by modern seawater, with the uppermost Holocene aquifer influenced by evaporation and leaching processes, the central late Pleistocene aquifer remaining relatively stable, and the lower middle Pleistocene aquifer affected by subsurface low salinity runoff and exhibiting an increasing trend with depth. Given the presence of numerous hydrogeological environments globally that are similar to the study area, the obtained mechanisms of groundwater salinization in this study will provide theoretical support for groundwater management in similar regions worldwide. [ABSTRACT FROM AUTHOR]

Elevated and increasing NO3− ${{\text{NO}}_{3}}^{-}$ concentration in groundwater affect groundwater supplies in China and elsewhere. However, how groundwater flow affects NO3− ${{\text{NO}}_{3}}^{-}$ concentration in groundwater has yet to be fully understood. Herein, multi‐isotopes (15N, 11B, 18O, and 2H) and local indicators of spatial association (LISA) were used to elucidate the spatiotemporal variation, sources, and patterns of NO3− ${{\text{NO}}_{3}}^{-}$ and its response to groundwater flow in Poyang Lake Basin where agriculture, industry and urban coexist. The location of NO3− ${{\text{NO}}_{3}}^{-}$ hotspots identified by LISA tended to move from the middle to lower reaches of Ganfu Plain with groundwater flow, and hotspots area expanded in the upper reaches of Xin River Basin and northwest of the study area during the transition from dry season to wet season. Our results revealed that variations of regional NO3− ${{\text{NO}}_{3}}^{-}$ concentration were controlled by groundwater recharge or flow mode (vertical or lateral), biogeochemical processes and sources (sewage and manure). In some areas with the single stratigraphic structure (unconfined aquifer), spatiotemporal variation of NO3− ${{\text{NO}}_{3}}^{-}$ concentration was influenced by local pollution sources and vertical recharge of current precipitation (vertical flow). In some areas with binary structures (confined aquifer), groundwater was mainly recharged by lateral flow and NO3− ${{\text{NO}}_{3}}^{-}$ concentration was mainly affected by mixing effect of upstream groundwater, reflecting human activities in the upper reaches rather than local human activities. In lakeside floodplain, groundwater NO3− ${{\text{NO}}_{3}}^{-}$ was attenuated by the dissimilatory NO3− ${{\text{NO}}_{3}}^{-}$ reduction to NH4+ ${{\text{NH}}_{4}}^{+}$. This study provides a novel insight into groundwater flow controlling on spatiotemporal distribution of NO3− ${{\text{NO}}_{3}}^{-}$ concentration in the regional scale. Key Points: Regional‐seasonal changes of hotspots and cool spots of nitrate concentration were identified by local indicators of spatial associationNitrate hotspots showed a seasonal shift along flow or expansion dominated by groundwater recharge mode linked with aquifer heterogeneityWe developed a conceptual model of spatiotemporal variation in regional nitrate content that describes the crucial role of groundwater flow [ABSTRACT FROM AUTHOR]

Glacial and snow meltwater from high mountains plays a critical role in the regulation of river discharge and impacts the irrigation of croplands in arid regions. In this study, the variable infiltration capacity (VIC)-glacier hydrological model combined with a crop yield model (CROPR model) was used to investigate the significance of meltwater to irrigation and cotton yield in the Yarkant River basin of arid Northwest China. The results indicated that the annual meltwater followed an increasing trend at a rate of 0.5 mm/10 a during 1960–2017. The warm–dry to warm–wet climate during recent decades has been driving the increasing annual total discharge and meltwater and the decreasing total irrigation, irrigation from meltwater and contribution of meltwater to cotton yield. The effect of precipitation on irrigation from meltwater and the contribution of meltwater to cotton production were greater than those of temperature. Increasing precipitation decreased the impact of meltwater on irrigation and cotton production. This study is helpful for the scientific management of cryospheric water resources and addressing the risk of water shortages in the arid region of Northwest China. [ABSTRACT FROM AUTHOR]

Background: Malnutrition is associated with poor overall survival (OS) in breast cancer patients; however, the most predictive nutritional indicators for the prognosis of patients with breast cancer are not well-established. This study aimed to compare the predictive effects of common nutritional indicators on OS and to refine existing nutritional indicators, thereby identifying a more effective nutritional evaluation indicator for predicting the prognosis in breast cancer patients. Methods: This prospective study analyzed data from 776 breast cancer patients enrolled in the "Investigation on Nutritional Status and its Clinical Outcome of Common Cancers" (INSCOC) project, which was conducted in 40 hospitals in China. We used the time-dependent receiver operating characteristic curve (ROC), Kaplan–Meier survival curve, and Cox regression analysis to evaluate the predictive effects of several nutritional assessments. These assessments included the patient-generated subjective nutrition assessment (PGSGA), the global leadership initiative on malnutrition (GLIM), the controlling nutritional status (CONUT), the nutritional risk index (NRI), and the prognostic nutritional index (PNI). Utilizing machine learning, these nutritional indicators were screened through single-factor analysis, and relatively important variables were selected to modify the PNI. The modified PNI, termed the cholesterol-modified prognostic nutritional index (CPNI), was evaluated for its predictive effect on the prognosis of patients. Results: Among the nutritional assessments (including PGSGA, GLIM, CONUT, NRI, and PNI), PNI showed the highest predictive ability for patient prognosis (time-dependent ROC = 0.58). CPNI, which evolved from PNI, emerged as the superior nutritional index for OS in breast cancer patients, with the time-dependent ROC of 0.65. It also acted as an independent risk factor for mortality (p < 0.05). Moreover, the risk of malnutrition and mortality was observed to increase gradually among both premenopausal and postmenopausal age women, as well as among women categorized as non-overweight, overweight, and obese. Conclusions: The CPNI proves to be an effective nutritional assessment tool for predicting the prognosis of patients with breast cancer. [ABSTRACT FROM AUTHOR]

A thorough understanding of groundwater recharge is critical for sustainable groundwater development in semi-arid areas. To determine the recharge regime in one alluvial-proluvial fan aquifer which usually acts as the main recharge zone of its local groundwater, field surveys and isotopic analyses were conducted in the piedmont region of the South Taihang Mountains of the North China Plain during the rainy (August) and dry (November) seasons. Precipitation could not effectively provide short-term recharge to the alluvial-proluvial fan aquifer due to the deep water table. The fault buried by the mountain front alluvial-proluvial deposits acts as a barrier, inhibiting effective recharge to the overlying Quaternary aquifer. Sulfate concentration and isotopes were more elevated in deep groundwater of the alluvial-proluvial fan area compared to that in the depression region, suggesting that lower deep groundwater potential has resulted in the inter-aquifer flow from the shallow alluvial-proluvial fan aquifer feeding the deep aquifer underneath. Inter-aquifer leakage showed an inverse relationship with the distance from the mountain edge, and its recharge may be influenced by the distribution of the aquitard in the deep aquifer of the proximal fan, leading to a decreased contribution of inter-aquifer leakage. Additionally, the deep groundwater flow in the Sha River alluvial-proluvial fan is disturbed by the hydraulic potential decline in the proximal fan region, as exhibited by a more complex flow pattern and reduced groundwater mixing zone. Our results increase understanding of piedmont hydrology and the management of its related water resources. [ABSTRACT FROM AUTHOR]

Identifying nitrate sources and migratory pathways is crucial for controlling groundwater nitrate pollution in agricultural watersheds. This study collected 35 shallow groundwater samples in the Nansi Lake Basin (NLB) to identify groundwater nitrate sources and potential health risks. Results showed that NO 3 - concentration in 62.9% of groundwater samples exceeded the drinking water standard (50 mg/L). Hierarchical cluster analysis (HCA) was used to classify the sampling points into three groups based on hydrochemical and isotopic data. Groups A and C were situated in the eastern recharge and discharge regions of Nansi Lake, while Group B was located in the Yellow River floodplain west of the lake. Hydrochemical data and nitrate stable isotopes (δ 15 N-NO 3 - and δ 18 O-NO 3 - ) indicated that elevated NO 3 - primarily originated from soil organic nitrogen (SON) in Group A, while manure and sewage (M&S) were the primary sources in Groups B and C samples. Microbial nitrification was identified as the primary nitrogen transformation process across all groups. The source apportionment results indicated that SON contributed approximately 40.1% in Group A, while M&S contributed about 53.9% and 81.2% in Groups B and C, respectively. The Human Health Risk Assessment (HHRA) model indicated significant non-carcinogenic risks for residents east of Nansi Lake, primarily through the oral pathway, with NO 3 - concentration identified as the most influential factor by sensitivity analysis. These findings provide new perspectives on identifying and handling groundwater nitrogen pollution in agriculture-dominated NLB and similar basins that require enhanced nitrogen contamination management., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

This study investigates the chemical characteristics, formation, and sources of inorganic nitrogen (IN) of shallow groundwater across the Sanjiang Plain, aiming to enhance drinking water safety management and pollution control. A total of 167 groundwater and 27 surface water samples were collected for constituents and isotopes (H 2 and O 18 ). The hydrogeochemical characteristics showed that the major type is HCO 3 - Ca·Mg, with low total dissolved solids and a neutral to weak alkaline nature. Rock weathering processes govern the hydrochemical composition of groundwater. Hydrogen and oxygen stable isotopes analyses revealed that precipitation serves as the main water source. In alluvial areas, oxidative conditions lead to the enrichment of NO 3 -N concentrations, with sewage, manure, and fertilizers being the primary IN sources. In lacustrine areas, intensive rice cultivation results in reductive conditions and strong denitrification processes, causing the loss of NO 3 -N and leaving NH 4 -N as the dominant IN form. Organic matter mineralization is likely a more significant contributor to NH 4 -N concentrations than ammonium fertilizers. These findings provide valuable information for further research on natural sources and groundwater pollution in areas with similar hydrogeological conditions. PRACTITIONER POINTS: Rock weathering processes govern the hydrochemical composition of groundwater, and precipitation serves as the main water source. In alluvial areas, oxidative conditions lead to the enrichment of NO 3 -N. In lacustrine areas, intensive rice cultivation results in reductive conditions and strong denitrification processes. Organic matter mineralization is likely a more significant contributor to NH 4 -N concentrations than ammonium fertilizers. These findings provide references for water management and information for further research on natural sources and groundwater pollution in areas with similar hydrogeological conditions., (© 2024 Water Environment Federation.)

The Xiaomojiu landslide is a typical high-elevation, long-runout landslide located in the Jinsha River Corridor. In this study, sequential InSAR time-series estimation was used to calculate the line of sight (LOS) surface displacements with descending and ascending Sentinel-1 images, and it turned out that the cumulative LOS surface displacement of the landslide was up to −78.4 mm during the period from October 2017 to April 2021 with the maximum LOS surface displacement rate of −38.5 mm/year. The landslide body could be divided into five zones (A, B1, B2, B3, and C) according to its topographical characteristics together with the LOS surface displacement time series. Combining engineering geological characteristics, LOS cumulative surface displacements with site investigation suggest that the Xiaomojiu landslide is likely to be a precipitation-triggered ancient traction rock landslide at the accelerated deformation stage. A dynamic simulation of the Xiaomojiu landslide with the PFC3D software shows that it could take approximately 65 s for the Xiaomojiu landslide from start-up to acceleration to deceleration to build-up of a barrier lake, followed by a simulation from the barrier lake to outburst floods with the HEC-RAS software indicating that the maximum depth of the outburst floods could be 13.5 m (15%), 24.6 m (25%), 42.1 m (50%), and 50.3 m (75%) along Qinghai-Tibet Plateau Transportation Corridor (QTPTC). It is believed that the results of this study provide a reference for landslide prevention along the QTPTC and the Jinsha River. [ABSTRACT FROM AUTHOR]

Systematic measurements of water temperature are lacking but useful in understanding the relationship between water temperature and earthquakes. Based on the water temperature data, geological structure, borehole structure, and temperature gradient in the Jinjia well, Southwest China, we systematically analysed the water temperature changes related to earthquakes. The water temperature of the Jinjia well recorded the coseismic changes caused by the Wenchuan M7.9 and Panzhihua M6.1 earthquakes in 2008. We also found abnormal changes in the water temperature, after which moderate to strong earthquakes occurred in the surrounding region. The preseismic abnormal changes of the Jinjia well were rising-recovery (rising to a high value and continuing for a period of time before decreasing or quickly recovering), with the range of 0.007–0.07 °C. The maximum change (0.07 °C) occurred before the M7.9 Wenchuan earthquake in 2008. According to the Molchan error diagram, the most likely time for an earthquake to occur is within approximately 4 months after the water temperature exceeds the threshold temperature. In the Jinjia well, the installation depth of the temperature sensor affected the correlation between the temperature changes and earthquakes with a seismic energy density above 10−3 J·m−3. The shorter the distance between the sensor and the fault, the higher the probability of water temperature changes related to earthquakes. [ABSTRACT FROM AUTHOR]

High-quality, freely accessible, long-term precipitation estimates with fine spatiotemporal resolution play essential roles in hydrologic, climatic, and numerical modeling applications. However, the existing daily gridded precipitation datasets over China are either constructed with insufficient gauge observations or neglect topographic effects and boundary effects on interpolation. Using daily observations from 2839 gauges located across China and nearby regions from 1961 to the present, this study compared eight different interpolation schemes that adjusted the climatology based on a monthly precipitation constraint and topographic characteristic correction, using an algorithm that combined the daily climatology field with a precipitation ratio field. Results from these eight interpolation schemes were validated using 45 992 high-density daily gauge observations from 2015 to 2019 across China. Of these eight schemes, the one with the best performance merges the Parameter-elevation Regression on Independent Slopes Model (PRISM) in the daily climatology field and interpolates station observations into the ratio field using an inverse-distance weighting method. This scheme had median values of 0.78 for the correlation coefficient, 8.8 mm d -1 for the root-mean-square deviation, and 0.69 for the Kling–Gupta efficiency for comparisons between the 45 992 high-density gauge observations and the best interpolation scheme for the 0.1 ∘ latitude × longitude grid cells from 2015 to 2019. This scheme had the best overall performance, as it fully considers topographic effects in the daily climatology field and it balances local data fidelity and global fitting smoothness in the interpolation of the precipitation ratio field. Therefore, this scheme was used to construct a new long-term, gauge-based gridded precipitation dataset for the Chinese mainland (called CHM_PRE, as a member of the China Hydro-Meteorology dataset) with spatial resolutions of 0.5, 0.25, and 0.1 ∘ from 1961 to the present. This precipitation dataset is expected to facilitate the advancement of drought monitoring, flood forecasting, and hydrological modeling. Free access to the dataset can be found at 10.6084/m9.figshare.21432123.v4 (Han and Miao, 2022). [ABSTRACT FROM AUTHOR]

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Land subsidence (LS) is becoming one of the major problems in coastal and delta cities worldwide. Understanding the current LS situation and the research trends is of paramount importance for further studies and addressing future international research networks. We analyzed the LS-related literature available from the Scopus database. The use of a single database avoided the redundancy of articles, while excluding some subject areas was useful to obtain only studies related to LS. By using VOSviewer and CiteSpace tools, we conducted a bibliometric analysis by considering title, keywords, and abstract to identify the temporal development, the geographical origin, and the area of study of the research. The results revealed a considerable heterogeneity of approaches, thematics, study areas, and research output trends. China, the US, and Italy are the major contributors to the scientific production, but the higher number of articles is not always related to the extension of the LS phenomenon in these countries. The monitoring approach differs worldwide, and univocal modeling is still lacking; from the analysis of the keywords, it is clear that the focus of most studies is on the relationship with the hydrological/hydrogeological aspects. Since the 2000s, however, the development of SAR technologies has boosted the study of the phenomenon from a different point of view. [ABSTRACT FROM AUTHOR]

Although many mechanisms of earthquake-induced hydrological response have been proposed in recent decades, the origins of these responses remain enigmatic, and a quantitative understanding of them is lacking. In this study, we quantitatively analyze the mechanism of coseismic response in water level and flow rate from an artesian well in southwestern China before and after multiple earthquakes and reveal the origin of the earthquake-induced hydrological response based on the monitoring data of water temperature. Water level and temperature always show coseismic step-like increases following earthquakes, which are independent of the earthquakes' epicentral distances and magnitudes. Tidal analysis finds changes in aquifer and acquitard permeability following these earthquakes, which corresponds to the post-seismic total discharge of 85–273 m 3 in 20 d after earthquakes. Furthermore, we couple the flow rate and temperature data to model the mixing processes that occurred following each earthquake. The results indicate that coseismic temperature changes are the result of the mixing of different volumes of water from shallow and deep aquifers, with the mixing ratio varying according to each earthquake. [ABSTRACT FROM AUTHOR]

As one of the vital shrubs growing in crusted areas in China, Artemisia ordosica (belonging to the Asteraceae family) is abundant in essential oil, and its aerial part's essential oil has been reported to have some biological activities during the flowering and fruit set stage, and has been used in folk medicine. However, little is known about the biological activities of its aerial part's essential oil during the vegetative period. Thus, the purpose of this work was to determine the chemical composition and evaluate the antioxidant and antibacterial potencies of the essential oil extracted from A. ordosica aerial parts during the vegetative stage. Gas chromatography coupled with mass spectrometry (GC-MS) revealed that spathulenol (9.93%) and α-curcumene (9.24%), both sesquiterpenes, were the most abundant of the 74 chemical constituents detected in the essential oil of A. ordosica. The antioxidant activity of the essential oil was found to be relatively moderate against 2,2-diphenylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and hydroxyl radical (OH●) radicals. The essential oil exhibited strong antibacterial activity against Staphylococcus aureus, Salmonella abony and Escherichia coli, with minimum inhibitory concentrations (MICs) of 2.5, 5, and 10 μL/mL, respectively. The results indicate that the essential oil of A. ordosica possesses notable antibacterial properties as well as antioxidant capability and can thus be employed as a natural ingredient which can be used as a substitute for antibiotics in the animal feed industry. However, in vivo toxicological studies are still required to determine the safety level and beneficial outcomes of the A. ordosica essential oil for future utilization. [ABSTRACT FROM AUTHOR]

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Investigating the spatial and temporal changes in snow cover over mountain areas is significant for understanding the impact of regional climate variability. In this study, using cloud‐removed snow cover data, which are generated based on Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow cover products, the spatiotemporal changes of snow cover fraction (SCF) and its relationship with temperature and precipitation changes from 2002 to 2020 were examined over Altai Mountains, China. The results demonstrate that the distribution and changes of SCF are highly spatiotemporally heterogeneous. Within a year, the maximum SCF occurs in January at 98.6%, and the minimum appears in July at 8.7%. The annual‐mean SCF shows an increasing trend at 0.09%·annum−1, owing to the significantly increasing SCF in the snow accumulation period at 0.5%·annum−1 and the decreasing SCF in the snow melting period at −0.2%·annum−1. The SCF distribution, as well as its interannual change, is greatly influenced by elevation. During the snow cover period, a positive linear correlation between SCF and elevation is found at 0.02%·m−1 (p <.01). The annual‐mean SCF decreases in the area below 1,200 m, whereas it increases in the area above 1,200 m. Accordingly, the elevation‐dependent SCF results in various SCF distributions on different slopes and watersheds. The SCF shows an apparent pattern in different aspects, with similar SCFs between the north and east aspects and between the west and south aspects but a difference between the northeast aspects and the westsouth aspects. The SCF is negatively correlated with air temperature (r = −0.74, p < 0.01) and positively correlated with precipitation (r = 0.74, p < 0.01). In addition, temperature shows a significant and larger correlation with SCF in both the snow accumulation and melting periods, indicating the major factor of temperature for the changes in SCF. [ABSTRACT FROM AUTHOR]

Alzheimer's disease is the most common neurodegenerative disease. Prior to 2017, National Medical Products Administration approved only four drugs to treat Alzheimer's disease, including three cholinesterase inhibitors and one N-methyl-D-aspartate receptor antagonist. We queried ClinicalTrials.gov to better understand Alzheimer's drug development over the past 5 years and found 16 promising candidates that have entered late-stage trials and analyzed their impact on clinical treatment of Alzheimer's disease in China. The 16 compounds selected include disease-modifying therapies and symptomatic therapies. The research and development pipeline now focuses on disease-modifying therapies such as gantenerumab, aducanumab, ALZ-801, ALZT-OP1, donanemab, lecanemab, simufilam, NE3107, semaglutide, and GV-971, which could put an end to the situation where Alzheimer's patients in China have no effective treatment alternatives. The reuse of drugs or combinations currently under investigation for the psychiatric treatment of Alzheimer's disease, including AXS-05, AVP-786, nabilone, brexpiprazole, methylphenidate, and pimavanserin, could provide physicians with additional treatment options. Although most of these drugs have not been explored in China yet, due to the current development trend in this field in China, it is expected that China will be involved in research on these drugs in the future. [ABSTRACT FROM AUTHOR]

Osteoporosis is a metabolic skeletal disorder characterized by increased fragility and fracture risk as s result of reduced bone mineral density and microstructural destruction and caused a heavy burden on families and society. Current medicines, on the other hand, have some limitations, with side effects and doubts regarding long-term efficacy being highlighted. Studies seeking for natural constituents as potential treatment options therefore come into focus. Icariin is a phytochemical derived from a traditional Chinese medicine, Herba epimedium, that has been used to treat orthopedic disorders in ancient China for thousands of years, including osteoporosis, osteoarthritis, and fracture. Icariin belongs to a category of prenylated flavonoids and has been shown to help reduce osteoporosis bone loss while having relatively low side effects. Icariin's anti-osteoporosis properties manifest in a variety of ways, like promoting osteogenesis, suppressing osteoclastogenesis and bone resorption, regulating migration, proliferation, and differentiation of mesenchymal stem cells, enhancing angiogenesis, anti-inflammation, and antioxidation. These procedures entail a slew of critical signaling pathways, such as PPARγ, ERα/AKT/β-catenin, and MAPK. Therefore, icariin can be an applicable alternative to improve osteoporosis although the underlying mechanisms have yet to be fully understood. In this study, we searched using the terms "icariin" and "osteoporosis," and included 64 articles meeting the inclusion criteria and reviewed the research of icariin in anti-osteoporosis over the last 10 years, and discussed new prospects for future study. Therefore, this review may provide some references for further studies. [ABSTRACT FROM AUTHOR]

Background: China's terrestrial ecosystems play a pronounced role in the global carbon cycle. Here we combine spatially-explicit information on vegetation, soil, topography, climate and land use change with a process-based biogeochemistry model to quantify the responses of terrestrial carbon cycle in China during the 20th century. Results: At a century scale, China's terrestrial ecosystems have acted as a carbon sink averaging at 96 Tg C yr− 1, with large inter-annual and decadal variabilities. The regional sink has been enhanced due to the rising temperature and CO2 concentration, with a slight increase trend in carbon sink strength along with the enhanced net primary production in the century. The areas characterized by C source are simulated to extend in the west and north of the Hu Huanyong line, while the eastern and southern regions increase their area and intensity of C sink, particularly in the late 20th century. Forest ecosystems dominate the C sink in China and are responsible for about 64% of the total sink. On the century scale, the increase in carbon sinks in China's terrestrial ecosystems is mainly contributed by rising CO2. Afforestation and reforestation promote an increase in terrestrial carbon uptake in China from 1950s. Although climate change has generally contributed to the increase of carbon sinks in terrestrial ecosystems in China, the positive effect of climate change has been diminishing in the last decades of the 20th century. Conclusion: This study focuses on the impacts of climate, CO2 and land use change on the carbon cycle, and presents the potential trends of terrestrial ecosystem carbon balance in China at a century scale. While a slight increase in carbon sink strength benefits from the enhanced vegetation carbon uptake in China's terrestrial ecosystems during the 20th century, the increase trend may diminish or even change to a decrease trend under future climate change. [ABSTRACT FROM AUTHOR]

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Aim: To evaluate the health status of nurses in China and explore the impact of work‐related stress, work environment and lifestyle factors on their health outcomes. Design: The Chinese Nurses' Health Study is a multicentred, prospective cohort study. Methods: We plan to recruit approximately 80,000 registered nurses aged between 18 and 65 years. Eligible nurses will be introduced to complete a series of web‐based questionnaires after obtaining their informed consent. Follow‐up questionnaires will be completed at 2‐year interval to continuously track subsequent exposures. Health‐related indicators will be obtained through self‐reporting by nurses and the provincial and national registry platforms such as National Central Cancer Registry. The funding was approved in July 2020 and Research Ethics Committee approval was granted in February 2021. Discussion: The study is the first multicentred prospective cohort study that aims to assess the impact of work‐related stress, work environment and lifestyle factors on the health of Chinese nurses. The results of the Chinese Nurses' Health Cohort Study will potentially draw a picture of the current situation of general health and well‐being among nurses in China and their health risks. This will be critical in recommending locally tailored strategic preventive measures and policies to reduce health and well‐being threats for nurses and potentially general public, thereby promoting the quality of healthcare in China and globally. Impact This study will help to understand the health status and working environment characteristics of Chinese nurses, and provide valuable epidemiological evidence for improving working environment and promoting well‐being. The results of this study are potentially of great significance for formulating targeted nursing strategies to promote the nurses' health, nursing quality and patient safety in China and even around the world. Clinical Trial Registration Number and name of trial register: ChiCTR.org (ID:ChiCTR2100043202), The Nurses' Health Cohort Study of Shandong. [ABSTRACT FROM AUTHOR]

Lung adenocarcinoma (LUAD) is one of the most common malignant tumors with high morbidity and mortality in China and worldwide. Long non-coding RNAs (lncRNAs) as the competing endogenous RNA (ceRNA) play an essential role in the occurrence and development of LUAD. However, identifying lncRNA-related biomarkers to improve the accuracy of LUAD prognosis remains to be determined. This study downloaded RNA sequence data from The Cancer Genome Atlas (TCGA) database and identified the differential RNAs by bioinformatics. A total of 214 lncRNA, 198 miRNA and 2989 mRNA were differentially identified between LUAD and adjacent nontumor samples. According to the ceRNA hypothesis, we constructed a lncRNA-miRNA-mRNA network including 95 protein-coding mRNAs, 7 lncRNAs and 15 miRNAs, and found 24 node genes in this network were significantly associated with the overall survival of LUAD patients. Subsequently, through LASSO regression and multivariate Cox regression analyses, a four-gene prognostic signature composed of GPI, IL22RA1, CCT6A and SPOCK1 was developed based on the node genes of the lncRNA-mediated ceRNA network, demonstrating high performance in predicting the survival and chemotherapeutic responses of low- and high-risk LUAD patients. Finally, independent prognostic factors were further analyzed and combined into a well-executed nomogram that showed strong potential for clinical applications. In summary, the data from the current study suggested that the four-gene signature obtained from analysis of lncRNA-mediated ceRNA could serve as a reliable biomarker for LUAD prognosis and evaluation of chemotherapeutic response. [ABSTRACT FROM AUTHOR]

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The Huanglong travertine landscape, which is located on the eastern edge of the Qinghai‐Tibet Plateau, is a World Natural Heritage Site with important tourism, aesthetic and scientific research value. However, no convincing travertine sedimentary age data have been reported for this area, and these late Cenozoic terrestrial carbonates have not been effectively included in studies of the Qinghai‐Tibet Plateau geological environment. In this study, U‐series dating of the travertines was carried out using a multi‐collector inductively coupled plasma mass spectrometer to determine a time series for travertine deposition in the Dawan Valley (only a mountain away from Huanglong). The analyses of the processes operating during travertine deposition as the trench system evolved are performed based on a comprehensive study of the geological setting, structure and glacial landforms. The results suggest that travertine deposition in the Dawan Valley started at ca 13 ka and had begun to wane by the early Holocene (ca 7 ka). At the same time, the Huanglong Valley travertines began to be deposited on a large scale in response to a hydrological transition event. This event might reflect tectonic activity in particular, or possibly earthquakes or glacial retreat caused by climate warming. The findings reported here provide age data for late Cenozoic geological and environmental events such as climate variations and continental activity on the eastern margin of the Qinghai‐Tibet Plateau. It also presents new insights for research on glaciation, tectonic activity and seismicity; however, depositional breaks and forcing factors need to be explored further. [ABSTRACT FROM AUTHOR]

It is of significance to elucidate the groundwater quality and hydrogeochemical processes for sustainable utilization of groundwater resources in water shortage regions. A total of 256 groundwater samples were collected in typical watersheds in Zhangjiakou, northern China. The hydrochemical parameters, conventional ions, and trace elements were measured, and δD and δ18O data were collected to delineate the groundwater quality and hydrogeochemical processes. The results showed that 32.91% of the groundwater could be directly used for drinking water sources in the Bashang Plateau, north of the study area. The F− and NO3−-N were the main parameters above the standard threshold for drinking water. In contrast, the groundwater quality in the Baxia River Basins, south of the study area, was of a better scenario. Nonetheless, high concentrations of F−, total hardness, and SO42− were still observed. Most samples in the Bashang Plateau had relatively higher salinity than the Baxia River Basins. Both surface water and groundwater in the study area originated from local meteoric water with considerable hydraulic connections. The high-fluoride groundwater was primarily formed by dissolution of fluoride-rich minerals under conditions of high pH and Na+, low Ca2+, and rich in HCO3−. The dissolution of carbonate and silicate minerals accompanied by strong cation exchange and weak evaporation was the dominant water-rock interaction affecting the hydrochemical composition of groundwater, and anthropogenic NO3− input had an extra influence on hydrochemical process. This study provides a scientific guideline for the protection and allocation of local groundwater resources. [ABSTRACT FROM AUTHOR]

This paper aims to compare the performance of typical open global DEM datasets by using the indexes of elevation error, relative error and hydrologic network. Taking Fenhe River Basin of China as the study area, this research made quantitative performance comparison among four typical open global DEM datasets including SRTM data with 1" (SRTM1) and 3" (SRTM3) resolutions, ASTER Global DEM data at the 2nd version (GDEM-v2) and ALOS World 3D-30 m (AW3D) data. Through process and selection, more than 80,000 ICESat/GLA14 points were used as the reference data, and the elevation error was computed and compared accordingly. Furthermore, relative error was analyzed using slope values, and false slope ratio index was computed and categorically compared. Finally, the hydrologic networks extracted from the four DEM datasets were compared to the reference hydrologic network acquired by visual interpretation from remote sensing images. The research results show that the AW3D has the best performance, which is approximate to but a little better than SRTM1. The performance of SRTM3 and GDEM-v2 is similar, which are much worse than that of AW3D and SRTM1, and the performance of GDEM-v2 is the worst of all. [ABSTRACT FROM AUTHOR]

The construction of terraces is a key soil conservation practice on agricultural land in China providing multiple valuable ecosystem services. Accurate spatial information on terraces is needed for both management and research. In this study, the first 30 m resolution terracing map of the entire territory of China is produced by a supervised pixel-based classification using multisource and multi-temporal data based on the Google Earth Engine (GEE) platform. We extracted time-series spectral features and topographic features from Landsat 8 images and the Shuttle Radar Topography Mission digital elevation model (SRTM DEM) data, classifying cropland area (cultivated land of Globeland30) into terraced and non-terraced types through a random forest classifier. The overall accuracy and kappa coefficient were evaluated by 10 875 test samples and achieved values of 94 % and 0.72, respectively. For terrace class, the producer's accuracy (PA) was 79.945 %, and the user's accuracy (UA) was 71.149 %. The classification performed best in the Loess Plateau and southwestern China, where terraces are most numerous. Some northeastern, eastern-central, and southern areas had relatively high uncertainty. Typical errors in the mapping results are from the sloping cropland (non-terrace cropland with a slope of ≥ 5 ∘), low-slope terraces, and non-crop vegetation. Terraces are widely distributed in China, and the total terraced area was estimated to be 53.55 Mha (i.e., 26.43 % of China's cropland area) by pixel counting (PC) method and 58.46 ± 2.99 Mha (i.e., 28.85 % ± 1.48 % of China's cropland area) by error-matrix-based model-assisted estimation (EM) method. Elevation and slope were identified as the main features in the terrace/non-terrace classification, and multi-temporal spectral features (such as percentiles of NDVI, TIRS2, and BSI) were also essential. Terraces are more challenging to identify than other land use types because of the intra-class feature heterogeneity, interclass feature similarity, and fragmented patches, which should be the focus of future research. Our terrace mapping algorithm can be used to map large-scale terraces in other regions globally, and our terrace map will serve as a landmark for studies on multiple ecosystem service assessments including erosion control, carbon sequestration, and biodiversity conservation. The China terrace map is available to the public at 10.5281/zenodo.3895585 (Cao et al., 2020). [ABSTRACT FROM AUTHOR]

Fractures play an important role in controlling the hydraulic conductivity of rock masses, and the aperture significantly influences the magnitude of fracture seepage. In this study, field measurements and experiments were conducted at a well-exposed granite fracture site in the Beishan area, China. Several types of single natural fractures were selected to remove the weathered surface and expose the fresh fractures. Subsequently, measuring ruler dispersion-tangent middle axis (MRD-TMA) method was developed to measure the fracture aperture and capture fracture geometry. Then, electrical resistivity tomography (ERT) technique was employed to investigate the seepage properties of these fractures. The results reveal that MRD-TMA method achieved good flexibility and accuracy in the current measurement of fracture aperture, and ERT is a useful tool for detecting the seepage properties of fractures in hard rock masses. Combined with field observations, the filling form of fractures can be categorized according to the ERT inversion results, as follows: open-weak filling, open filling, loose filling, and fully cemented-closed form, whose seepage properties decrease as the filling density increases. Generally, the open-weak filling is the main water channel in a fracture network, while the fully cemented-closed type is a water-blocking fracture and typically exhibits a pseudo-fracture with a large surface opening. In summary, the method for obtaining the morphological characteristics of the aperture can provide a low-cost and time-efficient approach for fracture logging in the field, and ERT technique provides a reference for the detection of potential hazards caused by connected water-conducting fractures in rock engineering. [ABSTRACT FROM AUTHOR]

Frequently occurring mega-droughts under current global climate change have attracted broad social attention. A paleoclimatic perspective is needed to increase our understanding of the causes and effects of droughts. South-western (SW) China has been threatened by severe seasonal droughts. Our current knowledge of millennial-scale dry and wet phases in this region is primarily based on the variability of the Indian summer monsoon. However, water availability over land does not always follow patterns of monsoonal precipitation but also depends on water loss from evaporation and transpiration. Here, we reconstructed precipitation intensity, lake hydrological balance and the soil water stress index (SWSI) for the last 27 000 years. Grain size, geochemical and pollen records from Yilong Lake reveal the long-term relationships and inconsistencies of dry–wet patterns in meteorological, hydrological and soil systems in the central Yunnan region, SW China. Our results show that the long-term trends among precipitation, hydrological balance and soil moisture varied through time. The hydrological balance and soil moisture were primarily controlled by temperature-induced evaporation change during periods of low precipitation such as the Last Glacial Maximum and Younger Dryas. During periods of high precipitation (the early to late Holocene), intensified evaporation from the lake surface offset the effects of increased precipitation on the hydrological balance. However, abundant rainfall and the dense vegetation canopy circumvented a soil moisture deficit that might have resulted from rising temperature. In conclusion, the hydrological balance in the central Yunnan region was more sensitive to temperature change while soil moisture could be further regulated by vegetation changes over millennial timescales. Therefore, under future climate warming, the surface water shortage in the central Yunnan region may become even more serious. Our study suggests that reforestation efforts may provide some relief to soil moisture deficits in this region. [ABSTRACT FROM AUTHOR]

The dynamic variations of groundwater have been extensively studied, but there are few studies on the long-term time–frequency features of groundwater dynamic variations. Here we report the dynamic characteristics of the groundwater level and dissolved radon concentration based on the long-term (January 1988–March 2018) daily observation records and regional precipitation data in the Tengchong area, China. The results show that the precipitation (2–3 years and 13 years), groundwater level (13 years), and dissolved radon (9 years) all have multi-year periodic variations, which might be controlled by climate and solar radiation. The groundwater levels were highly correlated with rainfall amount, while the radon concentration variations were not only affected by rainfall but also by other complex factors. Furthermore, the changes of groundwater level and radon concentration lagged behind that of precipitation by about 3 months, and as the cycle range increased, the lag time tended to stabilize. During the observation period, the dissolved radon concentrations increased and decreased sharply. Radon concentration remained correlated with precipitation during the anomalous period. After the anomaly disappeared in 2002, however, its annual periodic characteristics weakened. The increase of radon concentrations may cause a potential risk for water utilization that requires more attention. [ABSTRACT FROM AUTHOR]

High–arsenic (As) groundwater poses a serious threat to human health. The upper and middle reaches of the Yellow River are well–known areas for the enrichment of high–arsenic groundwater. However, little is known about the distribution characteristics and formation mechanism of high-As groundwater in the lower reach of the Yellow River. There were 203 groundwater samples collected in different groundwater systems of the lower Yellow River for the exploration of its hydrogeochemical characteristics. Results showed that more than 20% of the samples have arsenic concentrations exceeding 10 μg/L. The high-As groundwater was mainly distributed in Late Pleistocene–Holocene aquifers, and the As concentrations in the paleochannels systems (C2 and C4) were significantly higher than that of the paleointerfluve system (C3) and modern Yellow River affected system (C5). The high-As groundwater is characterized by high Fe2+ and NH4+ and low Eh and NO3−, indicating that reductive dissolution of the As–bearing iron oxides is probably the main cause of As release. The arsenic concentrations strikingly showed an increasing tendency as the HCO3− proportion increases, suggesting that HCO3− competitive adsorption may facilitate As mobilization, too. In addition, a Gibbs diagram showed that the evaporation of groundwater could be another significant hydrogeochemical processes, except for the water–rock interaction in the study area. Different sources of aquifer medium and sedimentary structure may be the main reasons for the significant zonation of the As spatial distribution in the lower Yellow River. [ABSTRACT FROM AUTHOR]

Groundwater is essential for the sustainable development of the Guanzhong Basin, China, and its quality is mainly controlled by hydrogeochemical processes and anthropogenic pollution. This study used statistical and multivariate statistical analysis approaches to recognize the hydrogeochemical processes and affecting factors of groundwater in the central part of the Guanzhong Basin. Correlations among 14 hydrochemical parameters were statistically examined. Principal component analysis (PCA), factor analysis (FA), and hierarchical cluster analysis (HCA) techniques were applied to analyze the physicochemical variables to understand the affecting factors of groundwater quality in the study area. The correlation analysis results indicate that cation exchange is the dominant process affecting the concentration of Na+ and Ca2+ in the groundwater. Both the PCA and FA indicate that minerals dissolution/precipitation and human activities are the key factors that affect groundwater quality. All parameters except CO32− and pH increase from C1 to C4 obtained through the Q mode HCA. C4 has a hydrochemical type of SO4–Na·K, indicating that the sample of this cluster is primarily influenced by anthropogenic processes. [ABSTRACT FROM AUTHOR]

Irrigation is the greatest human interference with the terrestrial water cycle. Detailed knowledge on irrigation is required to better manage water resources and to increase water use efficiency (WUE). This study applies a framework to quantify net irrigation at monthly timescale at a spatial resolution of 1 km2 providing high spatial and temporal detail for regional water resources management. The study is conducted in the Haihe River Basin (HRB) in China encompassing the North China Plain (NCP), a global hot spot of groundwater depletion. Net irrigation is estimated based on the systematic evapotranspiration (ET) residuals between a remote sensing‐based model and a hydrologic model that does not include an irrigation scheme. The results suggest an average annual net irrigation of 126 mm yr−1 (15.2 km3 yr−1) for NCP and 108 mm yr−1 (18.6 km3 yr−1) for HRB. It is found that net irrigation can be estimated with higher fidelity for winter crops than for summer crops. The simulated water balance for NCP is evaluated with Gravity Recovery and Climate Experiment (GRACE) data, and the net irrigation estimates can close the water balance gap. Annual winter wheat classifications reveal an increasing crop area with a trend of 2,200 km2 yr−1. This trend is not accompanied by a likewise increasing trend in irrigation water use, which suggests an increased WUE in the NCP, which is further supported by net primary productivity data. The proposed framework has potential to be transferred to other regions and support decision makers to support sustainable water management. Plain Language Summary: The irrigation of agricultural fields is taking place at unsustainable rates in many regions of the world. Despite the fact that irrigation is the largest anthropogenic impact on the natural water cycle, there exists limited knowledge of the applied irrigation amounts. This study applies an approach to estimate net irrigation, that is, the evaporative loss of irrigation water. The approach is applied on the Haihe River Basin in North‐Eastern China. For the estimation of net irrigation, two sources of evapotranspiration (ET) are considered. First, baseline ET is obtained from a rainfed hydrologic model without irrigation. Second, ET is obtained from a satellite remote sensing model, which represents rainfed and irrigated ET. We study the ET differences of the two sources to derive net irrigation amounts at monthly timescale at 1 km2 spatial resolution. Our analysis suggest an average annual net irrigation of 108 mm yr−1 (18.6 km3 yr−1). The results are evaluated against annual winter wheat classification maps as well as satellite‐based net primary productivity data and total water storage data (Gravity Recovery and Climate Experiment, GRACE). Our results indicate an increasing water use efficiency as a result of promoting water savings in the agricultural sector. Key Points: Net irrigation can be quantified by evapotranspiration residuals derived from hydrologic models and satellite remote sensingEstimation of winter wheat irrigation has lower uncertainty than estimation of irrigation of summer cropsIrrigation water use efficiency has improved in the North Chin Plain in the period 2002–2016 [ABSTRACT FROM AUTHOR]

Over the past decade global flood hazard models have been developed and continuously improved. There is now a significant demand for testing global hazard maps generated by these models in order to understand their applicability for international risk reduction strategies and for reinsurance portfolio risk assessments using catastrophe models. We expand on existing methods for comparing global hazard maps and analyse eight global flood models (GFMs) that represent the current state of the global flood modelling community. We apply our comparison to China as a case study and, for the first time, include industry models, pluvial flooding, and flood protection standards in the analysis. In doing so, we provide new insights into how these components change the results of this comparison. We find substantial variability, up to a factor of 4, between the flood hazard maps in the modelled inundated area and exposed gross domestic product (GDP) across multiple return periods (ranging from 5 to 1500 years) and in expected annual exposed GDP. The inclusion of industry models, which currently model flooding at a higher spatial resolution and which additionally include pluvial flooding, strongly improves the comparison and provides important new benchmarks. We find that the addition of pluvial flooding can increase the expected annual exposed GDP by as much as 1.3 percentage points. Our findings strongly highlight the importance of flood defences for a realistic risk assessment in countries like China that are characterized by high concentrations of exposure. Even an incomplete (1.74 % of the area of China) but locally detailed layer of structural defences in high-exposure areas reduces the expected annual exposed GDP to fluvial and pluvial flooding from 4.1 % to 2.8 %. [ABSTRACT FROM AUTHOR]

To make a reliable reconstruction of past climate from soil-surface modern pollen, it is necessary to reduce the sources of error. In this paper, pollen percentages of the sub-continental scale modern pollen-climate dataset from China and Mongolia (with 68% soil-surface samples) are homogenized at various spatial scales. A tailored calibration-set is then applied to lake sediment-surface pollen assemblages from north-central China to evaluate their predictive power. Results indicate that spatial homogenization of modern pollen percentages can increase the proportion of inertia explained by climatic variables in CCA and improve the model performance of leave-one-out cross-validation using WA-PLS. Soil-surface pollen assemblages can thus be employed into a calibration-set for reliable climate estimation and they perform better when the calibration-set has been locally homogenized. Small-scale (e.g., radii 2, 5, or 10 km) homogenization reduces the local noise in soil-surface pollen assemblages and improves the cross-validated performance, while broader scale homogenization (more than 20 km radius) blurs the pollen-climate relationship. Lake sediment-surface pollen assemblages from close to the shore could contain pollen grains transported by rivers or from the shore vegetation and thus fail to represent regional climate well like the assemblages from the central part and deep-water area of lake. [ABSTRACT FROM AUTHOR]

Using natural tracer profiles to study migration of porewater salinity can help determine fluid fluxes and the timescales of salinization and freshening in coastal regions. Saline groundwater associated with evaporation and transgression events is widely distributed in the North China Plain (NCP). However, the fluid flux, time scales, and importance of different salinization processes are poorly constrained, particularly in areas beyond the limit of marine influence. Chloride (Cl) and δ18O profiles were obtained from two boreholes: one drilled at the edge of the piedmont alluvial fan (HS borehole) and one in the coastal region (G1 borehole). Numerical simulation of Cl and δ18O profiles confirmed diffusion‐dominated solute transport but also indicated slow upward advective flow over geological timescales. The profile modeling at HS indicated that salinization related to evaporation has occurred since the Late Pleistocene. Assessment of alternative conceptual models indicates that intensive groundwater pumping in recent decades has also caused significant downward movement of saline porewater (e.g., movement of brackish water at ~0.6 m/yr), mixing modern or Holocene water with Pleistocene water. The coastal Cl profile modeling in contrast shows that porewater salinity can be primarily attributed to salt diffusion during four transgression/regression cycles since the late Middle Pleistocene. The Cl transport appears never to have reached an equilibrium state during the glacial‐interglacial cycles. This suggests not only that trapped Holocene seawater is still present and leaching into adjacent sediments but also that Pleistocene water has never been entirely flushed from the deep part of the coastal sediments. Key Points: Mechanisms and timescales of salinization/freshening processes were studied in coastal region where marine and nonmarine sources coexistDiffusion dominated migration of porewater salinity affected by upward advection and downward flow caused by intensive pumpingPleistocene water has never been entirely flushed from coastal sediments during glacial‐interglacial cycles [ABSTRACT FROM AUTHOR]

Overexploitation of groundwater has resulted in seawater intrusion in many semiarid and arid coastal areas. This study illustrates the origin of groundwater salinity and assesses seawater intrusion/extrusion process in the Yang-Dai River plain aquifer, by analyzing hydrochemical and stable isotopic compositions of surface water, groundwater, geothermal water, and seawater. A cone of depression in groundwater is caused by intensive groundwater pumping formed in the late 1980s in the alluvial Yang-Dai River plain. In the northern part, groundwater exploitation has caused seawater intrusion identified by Ca-Cl type water. However, the widely distributed silty clay prevented the seawater intrusion in the southern part, evidenced by Ca-HCO3 type water with depleted δ2H (−60 to −46‰) and δ18O (−8.9 to −4.7‰). Anthropogenic pollution also plays a significant role in groundwater salinization. The positive correlation between Cl and NO3- for most groundwater and the extremely high nitrate concentrations (up to 652.7 mg/L) indicate that fertilizer from agricultural activities has greatly influenced groundwater quality. Irrigation return flow evaporation during agricultural activities also accounts for groundwater salinity. Besides the intensive fertilizer usage, seawater intrusion and the established anti-tide dams reduced the surface water and groundwater discharge to the sea and then resulted in the extremely high nitrate concentration. This study may improve the understanding of the groundwater salinization processes in a complex coastal aquifer, which is greatly influenced by anthropogenic activities. [ABSTRACT FROM AUTHOR]

The present state of iron (Fe) and manganese (Mn) concentration in groundwater of Changchun city located within the Songnen Plain of northeastern China was evaluated in this study. Heavy metal sources, as well as triggering mechanism, were analyzed using a physicochemical, statistical and spatial approach. Results revealed that out of the 2600 samples analyzed, 214 (representing 8.24%) for Fe and 606 wells (representing 23.34%) for Mn exceeded the water standard. Organic matter–rich sediments and Fe-Mn nodules in aquifer and soil serve as sources of Fe and Mn. Organic and inorganic complex formations, as well as long residence time, were found to foster the release of Fe and Mn into groundwater. Additionally, pH and well depth was important in triggering Mn dissolution while groundwater mineralization, depth to the water table and well proximity to the river were found to have minimal/negligible effect on heavy metal mobilization. The removal of Fe and Mn from the water before use was proposed along with the sinking of deeper wells for groundwater exploitation to limit the use of polluted water. [ABSTRACT FROM AUTHOR]

In June 2019, an earthquake sequence comprising five M > 5 events occurred in a region of southwest China with fluid injection for both hydraulic fracturing and salt mining, which raised an extensive controversy on the cause. Here we use interferometric synthetic aperture radar (InSAR) observations to determine the source parameters of the sequence and to investigate the relationship with local injection activities. Both Sentinel‐1 and Advanced Land Observing Satellite 2 SAR images are collected to measure coseismic and preseismic surface deformation. Geodetic inversions with coseismic observations show that the sequence ruptured a previously unmapped southwest‐dipping thrust fault above 3 km depth, which intersects with the open‐hole sections of wells for solution mining of salt. In the 4 months before the sequence, cumulative line‐of‐sight displacements near the wells are around 1–2 cm after correcting seasonal‐like deformation. Our results indicate that water injection likely enhanced pore pressure within the fault zone and thus contributed to inducing the sequence. Plain Language Summary: Earthquakes are seldom reported in relation to fluid injection for salt mining. Here, we present a unique case of an earthquake sequence probably induced by such human activity in Changning (southwest China). The sequence began with a Ms 6.0 earthquake, which is an unprecedented magnitude and larger than the historical records of earthquakes induced by wastewater disposal and hydraulic fracturing. Due to the sparse distribution of seismic stations and the failure of a key station closest to injection wells for salt mining before the Ms 6.0 earthquake, available seismic data are not enough to constrain the spatial locations of events in the earthquake sequence. Here we instead use high spatial‐resolution interferometric synthetic aperture radar observations of coseismic surface deformation to image the causative fault of the sequence. We find that the open‐hole sections of injection wells intersect the seismogenic fault. Moreover, the cumulative surface displacements near the salt mine in the ~4 months before the sequence are 1–2 cm, which was mainly caused by ground uplift. Accordingly, we hypothesize that fluid injection increased pore pressure within the fault zone and brought it to rupture. Our interferometric synthetic aperture radar observations and inversion results present significant evidence toward the causality between salt mining and the earthquake sequence. Key Points: InSAR observations show significant ground deformation due to the Changning earthquake sequence near the salt mineInSAR inversions reveal that the Changning earthquake sequence ruptured a southwest‐dipping thrust fault above the depth of 3 kmThe open‐hole sections of wells injecting for solution mining of salt intersect the InSAR‐inferred seismogenic fault [ABSTRACT FROM AUTHOR]

Background: Ischemic stroke is a leading cause of morbidity and mortality. Thrombolytic therapy improves disability and survival rates; however, to be effective, it must be given within 4.5 h of onset. Moreover, thrombolytic therapy is frequently contraindicated. Therefore, alternative therapeutic options are required. In China, cinepazide maleate injection has been shown to improve the cerebral collateral circulation and further reduce disability in stroke patients; however, very few studies investigating this therapy have been conducted to date. Therefore, this study aimed to further confirm the efficacy and safety of cinepazide maleate injection in patients with acute ischemic stroke.Methods: Patients with acute ischemic stroke were administered an intravenous infusion of 320 mg cinepazide maleate or placebo once daily for 14 days. All patients were also administered basic therapy (citicoline sodium). The primary efficacy endpoint was the proportion of patients with a modified Rankin scale (mRS) ≤2 on day 90. Secondary efficacy endpoints included Barthel Index ≥95. Safety was evaluated by recording all adverse events (AEs), monitoring laboratory parameters and vital signs, and electrocardiogram.Results: In total, 937 patients with an acute ischemic stroke were included, with a mean (standard deviation, SD) National Institutes of Health Stroke Scale score of 8.8 (2.4) and a mean (SD) stroke onset of 30.9 (11.4) hours prior. Following treatment for 90 days, the proportion of patients with an mRS score ≤ 2 was significantly higher in the cinepazide maleate group than in the control group (60.9% vs. 50.1%; p = 0.0004). Moreover, the proportion of patients with a Barthel Index of ≥95 on day 90 was also significantly higher in the cinepazide maleate group than in the control group (53.4% vs. 46.7%; p = 0.0230). There were no statistically significant differences in safety parameters between the cinepazide maleate and control groups.Conclusions: The results of this study show that cinepazide maleate injection is superior to placebo in improving neurological function and activities of daily living, reducing disability, and promoting functional recovery in patients with acute ischemic stroke. Cinepazide maleate injection was safe and well tolerated with no unexpected AEs reported.Trial Registration: Chinese Clinical Trial Registry CTR20160292 and ChiCTR1900023827 . Retrospectively registered June 13, 2019. [ABSTRACT FROM AUTHOR]

A new significant aspect in the utilization of hydrothermal energy in China is the large-scale exploitation using multiwells from a single geothermal site. This requires detailed hydrogeochemical investigations to gain insight about deep groundwater circulation. At the Xiongxian karst geothermal site in North China, where the demonstration project of large-scale utilization was conducted, 40 boreholes with depths from 1000 to 1800 m were drilled in a region of 50 km2. A total of 25 water samples were collected, and temperature loggings were conducted in 16 of these wells. At the site scale, the hydraulic head was observed to decline from SW to NE, i.e., orthogonal to that at the regional scale. Moreover, the geothermal groundwater temperature, borehole temperature gradient, and heat flow in the caprock all exhibited the same spatial trend with the groundwater head. Based on the hydrogeochemical and temperature logging data, this was explained by mixing of lateral recharging groundwater with ascending thermal fluids through the Xiongxian Fault, after excluding the causes of pumping activities and geologic structure. In addition, geothermal groundwater 81Kr age was estimated to be approximately 760 k yr, which is much older than the 14C age of 20 to 30 k yr. The older 81Kr age implies a low renewability of deep groundwater circulation, which should be considered in terms of sustainable management in relation to the large-scale utilization of geothermal resources. [ABSTRACT FROM AUTHOR]

This paper focused on nitrate fate in the vadose zone (VZ) and its implications for groundwater vulnerability under different soil types in the agricultural area of Huaihe River Basin, China. Isotopic compositions of nitrate (δ15N and δ18O) along with NO3− and Cl− concentrations were determined in the VZ-shallow groundwater continuum beneath silty-loam and silty-clay-loam, which are distinctive in texture and organic carbon (OC). In the soil zone (< 1 m in depth), measured δ18O–NO3− suggested the ubiquitous of nitrification regardless of soil types. In the subsoil zone (> 1 m in depth), however, the concurrent enrichment of δ15N–NO3− and δ18O–NO3− indicated the occurrence of denitrification, which showed a dependence on subsoil properties. Specifically, during wheat and maize land uses, denitrification removed as much as 76 %–88 % of the total nitrate where the subsoil was dominated by stratified OC-rich silty-clay-loam. In contrast, only 0 %–28 % of the nitrate was degraded via denitrification where the subsoil was composed of uniform, OC-depleted silty-loam. Furthermore, inactive denitrification and higher permeability in the silty-loam VZ implied higher groundwater vulnerability. This observation was consistent with the fact that groundwater NO3−–N concentration beneath silty-loam (11.24 mg L−1) was over two times higher than that of the silty-clay-loam (5.32 mg L−1), where stricter fertilization management and conservation strategies should be applied to protect groundwater quality. [ABSTRACT FROM AUTHOR]

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A least-square solver is presented for groundwater flux estimation using the one-dimensional conduction–advection equation, which was numerically solved using the MacCormack scheme. This approach was utilized to estimate groundwater fluxes from observed borehole temperatures under conditions of surface warming in both rural and urban areas in Leizhou Peninsula, China. The estimated groundwater recharge rate is 0.423 m/year, while the discharge rate is 0.269 m/year. The groundwater recharge rates were obtained in the north part of the study area, and the discharge locations were on Nansan, Donghai and Luzhou Islands, which fit favorably with the regional groundwater flow pattern. Relatively high correlations and low root mean square errors were detected between observed and computed borehole temperature–depth profiles, indicating the estimation is reasonable. The misfit between the observed and computed data might be associated with the uneven distribution of ground surface temperature (GST) and vertical soil heterogeneity. The urban heat island effect contributes an increment of 0.006 °C per year to the GST in the study area, which induces a 0.96 °C higher subsurface temperature in both recharge and discharge areas. The utilization of surface air temperature (SAT) as the upper boundary might underestimate groundwater fluxes, which might lead to inaccurate information for regional groundwater resource management. [ABSTRACT FROM AUTHOR]

Identification of different pollution sources in groundwater is challenging, especially in areas with diverse land uses and receiving multiple inputs. In this study, principal component analysis (PCA) was combined with geographic information system (GIS) to explore the spatial and temporal variation of groundwater quality and to identify the sources of pollution and main factors governing the quality of groundwater in a multiple land-use area in southwestern China. Groundwater samples collected from 26 wells in 2012 and 38 wells in 2018 were analyzed for 13 water quality parameters. The PCA results showed that the hydro-geochemical process was the predominant factor determining groundwater quality, followed by agricultural activities, domestic sewage discharges, and industrial sewage discharges. Agriculture expansion from 2012 to 2018 resulted in increased apportionment of agricultural pollution. In contrast, economic restructure and infrastructure improvement reduced the contributions of domestic sewage and industrial pollution. Anthropogenic activities were found the major causes of elevated nitrogen concentrations (NO3−, NO2−, NH4+) in groundwater, highlighting the necessity of controlling N sources through effective fertilizer managements in agricultural areas and reducing sewage discharges in urban areas. The applications of GIS and PCA successfully identified the sources of pollutants and major factors driving the variations of groundwater quality in tested years. [ABSTRACT FROM AUTHOR]