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Plant phenology under changing climate is a critical factor controlling terrestrial vegetation productivity. However, large uncertainties exist due to different data sources and phenological parameter extraction methods. In this study, we took advantage of a suite of long-term field observational data in northern grassland of China to investigate the drivers of phenological shifts and their effect on the maximum aboveground net primary productivity (ANPPmax) across four representative grassland types during 1984–2017. Results showed that drivers of phenological events (i.e., start (SOS), end (EOS), and length (GSL) of the growing season) with warming influence dramatically differed among grassland types, indicating that the synergistic effect of temperature and precipitation should be highlighted. For temperate desert steppe and alpine meadow, GSL of dominant species was both significantly lengthened with temperature rising with averaged 0.94 days year−1 (P < 0.001) and 1.15 days year−1 (P < 0.001), respectively, while for typical temperate grassland, GSL was considerably shortened by an average of 0.58 days year−1 (P < 0.01) as a result of water deficit caused by sharp warming and precipitation decreasing in summer and autumn. For most grassland types in our study, both SOS and GSL were significantly correlated with ANPPmax under different precipitation gradients with SOS advanced and GSL extended leading to higher ANPPmax. Only the typical temperate grassland presents a relatively poor correlation between phenological events and productivity. Furthermore, compared with GSL, ANPPmax was more sensitive to the advancement of SOS for every 1-day phenological change. However, the effect of EOS on ANPPmax across the four grassland types was much weaker and unstable. There were spatial response differences between ANPPmax and phenological transition events, with the temperate meadow grassland tending to be more sensitive compared with three other grassland types. [ABSTRACT FROM AUTHOR]

During underground mining, accurate revelation on the deformation and failure mechanisms of a high-steep slope under multi-layer mining conditions facilitates the prevention and control of geological disasters in mines. Numerical simulation based on discrete element theory can be used to explore the characteristics and mechanism of action of deformation and failure of a slope under complex geological and multi-layer mining conditions. By utilising PFC2D (particle flow code) software, the deformation and failure characteristics of a high-steep slope in Faer Coal Mine in Guizhou Province, China were investigated. Additionally, the mechanism of influence of different numbers of mining layers on the deformation and failure of the high and steep slope was elucidated. The result showed that after the goaf passed by the slope toe, multi-layer mining aggravated the subsidence and deformation of the slope toe: the slope toppled forward as it sank. The toppling of the slope changed the slope structures: the strata in the front of the slope were transformed from anti-dip to down-dip features. Extruded by collapsed–toppled rock mass, the slope toe and the rock mass located in the lower part of the slope toe generally exhibited a locking effect on the slope. Multi-layer mining degraded the overall stability of the slope, in that the total displacement of the slope was much greater than the total mining thickness of the coal seams. Based on the aforementioned research, ideas for preventing and controlling geological disasters during mining operations under a high-steep slope were proposed. [ABSTRACT FROM AUTHOR]

Biological carbon pumping (BCP) is a key process in which dissolved inorganic carbon in terrestrial aquatic ecosystems is utilized by aquatic autotrophs for photosynthesis and transformed into autochthonous organic matter (AOC). However, the mechanisms underlying BCP and the amount of generated AOC deposited effectively, are still poorly understood. Therefore, we conducted a systematic study combining modern hydrochemical monitoring and a sediment trap experiment in Fuxian Lake (Yunnan, SW China), the second-deepest plateau, oligotrophic freshwater lake in China. Temperature, pH, EC (electrical conductivity), DO (dissolved O2), [HCO3−], [Ca2+], SIc, partial CO2 (pCO2) pressure, and carbon isotopic compositions of HCO3− (δ13CDIC) in water from Fuxian Lake all displayed distinct seasonal and vertical variations. This was especially apparent in an inverse correlation between pCO2 and DO, indicating that variations of hydrochemistry in the lake water were mainly controlled by the metabolism of the aquatic phototrophs. Furthermore, the lowest C/N ratios and highest δ13Corg were recorded in the trap sediments. Analyses of the C/N ratio demonstrated that the proportions of AOC ranged from 30% to 100% of all OC, indicating that AOC was an important contributor to sedimentary organic matter (OC). It was calculated that the AOC flux in Fuxian Lake was 20.43 t C km−2 in 2017. Therefore, AOC produced by carbonate weathering and aquatic photosynthesis could potentially be a significant carbon sink and may have an important contribution to solving the lack of carbon sinks in the global carbon cycle. [ABSTRACT FROM AUTHOR]

We developed a panel of multiplex quantitative real-time reverse transcription polymerase chain reaction (mqRT-PCR) assay consisting of seven internally controlled qRT-PCR assays to detect 16 different respiratory viruses. We compared the new mqRT-PCR with a previously reported two-tube mRT-PCR assay using 363 clinical sputum specimens. The mqRT-PCR assay performed comparably with the two-tube assay for most viruses, offering the advantages of quantitative analysis, easier performance, lower susceptibility to contamination, and shorter turnaround time in laboratories equipped with conventional real-time PCR instrumentation, and it could therefore be a valuable tool for routine surveillance of respiratory virus infections in China. [ABSTRACT FROM AUTHOR]

Fifteen individual perfluoroalkyl substances (PFASs) were analyzed in 22 sediment samples collected from Anqing urban lakes (Anhui province, China) by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Total PFAS concentration was between 0.61 and 26 ng g dry weight. Perfluorooctane sulfonate (PFOS) was the dominant PFAS contaminant, with a concentration range of < 0.040-13 ng g. Results indicated higher total PFAS concentrations in lakes located to the northwest of Anqing City than in other regions. Adjacent chemical and industrial factories were hypothesized to be responsible for these higher PFAS levels in those lakes. In comparison to other measurements obtained from other lakes, PFAS concentrations in the urban lakes of Anqing City were relatively high. [ABSTRACT FROM AUTHOR]

Deep mining practices are jeopardized by the recurrent instability and failure of roadways/multi-tunnels. This paper describes a case study of the mining-induced impacts on the stability and control strategy of overlying multi-tunnels with backfill mining in the Ping Dingshan No. 10 Coal Mine in Henan Province, China. To reveal the dynamic impacts of coal mining on the stability of overlying multi-tunnels, particularly in the process of mining cycle and after the overlying strata long-term stability period, a 3D finite element model was applied to explore the effect of longwall panel width, advancing distance, and backfill material’s compaction ratio (BMCR) on the multi-tunnels’ deformation characteristics. The results obtained demonstrate that failure and deformation of the overlying multi-tunnels become more pronounced with the increased longwall panel width and advancing distance, as well as with BMCR reduction. The ranking of deformation degree in the overlying multi-tunnels is as follows: main haulage roadway > auxiliary haulage roadway > main inclined shaft > rock crosscut > auxiliary inclined shaft. Using a 2D physical simulation experiment, a comprehensive analysis method and engineering design concept for the stability control of overlying multi-tunnels with backfill mining are put forward based on further research of the deformation characteristics of multi-tunnels using caving and backfilling method. The results obtained are instrumental to the stability control of overlying tunnels in deep mining practices with similar conditions. [ABSTRACT FROM AUTHOR]