Experiments were conducted to investigate the effects of warming and dominant plant species removal on net ecosystem CO2 exchange (NEE), ecosystem respiration (ER) and gross ecosystem production (GEP) along elevational gradients (3200 m and 4000 m) in the alpine meadow on the Tibetan Plateau. The results showed that GEP was higher than ER at both elevations, indicating that both ecosystems were a net C sink during the growing season in 2017. At a lower elevation (3200 m), warming did not have a significant effect on ecosystem C flux due to water limitation caused by warming. At a wetter high elevation (4000 m), warming significantly stimulated ecosystem C fluxes, on average, the warming-induced increase in GEP (2.30 mg CO2/(m2·s)) was higher than that in ER (0.62 mg CO2/(m2·s)), leading to an increase in NEE. Dominant plant species removal did not have a significant effect on ecosystem C flux at either elevations, probably due to the compensatory effects of the remaining species, because the removal on above ground biomass (AGB) or below ground biomass (BGB) was not significant at both elevations. There was no significant interaction between warming and dominant species removal on the ecosystem C fluxes at either elevations. The results reveal the importance of soil moisture in mediating the response of ecosystem C flux to climate warming in alpine meadow ecosystems, and removal of a single dominant plant species may not have a significant impact on ecosystem C flux in species-rich regions.
In order to explore spatiotemporal dynamics of soil extracellular enzyme activity (EEA) and its influence on potential mineralization rate of soil organic carbon (SOC) of the Daxing’an Mountain range, soil samples of three forests (Pinus sylvestris forest; Birch forest; Larch pine forest) and three ground cover plants in Larch forest (Grass; Ledum; Moss) were collected from Daxing’an Mountain range in summer and winter. Activities of six enzymes including carbon- (C) (β-1,4-glucosidase, β-1,4-xylosidase, β-D-cellobiohydrolase), nitrogen- (N) (N-acetyl-β-glucosaminidase, leucine aminopeptidase) and phosphorus- (P) (acid phosphatase) acquisition, potential mineralization rate of SOC and main environmental factors were analyzed and potential driving mechanisms were explored. Results showed that Both Pinus sylvestris forest and Birch forest exhibited significant higher activities of enzyme C, N and P in summer, however, Larch forest showed contrary seasonal dynamic with soil EEA of moss soil significantly higher in winter. From summer to winter, soils of three forests and three ground cover plants all experienced reduced P vs. N limitation. Besides, soils of Pinus sylvestris forest and Birch forest both experienced increased C vs. nutrient limitation, however, Larch forest showed contrary seasonal dynamics with the existence of moss. In Pinus sylvestris forest and Larch forest, potential mineralization rate of SOC exhibited higher in winter while Birch forest showed contrary trend. Analysis showed that potential mineralization rate of SOC was influenced by enzyme C and enzyme N significantly, whereas little influenced by enzyme P. C vs. nutrient limitation had little correlation while P vs. N limitation had significant negative correlation with potential carbon mineralization rate.
A N addition experiment was established with four treatments: control (no fertilization), low-N (20 kgN/(hm2·a)), medium-N (50 kgN/(hm2·a)) and high-N fertilization (100 kgN/(hm2·a)) in an N-limited Pinus sylvestris forest in Hebei Province, North China to study the production, biomass and turnover of fine root systematically. The results showed that fine root productivity (NPPfr) increased in low-N plots, decreased in high-N treatment, while the proportion of NPPfr to net primary productivity (NPP) reduced in low-N addition and increased in medium-N addition. With the increase of N availability, root biomass decreased, turnover rate increased, and carbon returned to soil decreased at first and increased later. The influence of N availability on NPPfr didn’t change with depth, while turnover rate varied among depth. N-addition made an impact on fine root productivity through soil nitrogen content, soil carbon content and soil pH, while affecting turnover rate of fine root by root carbon and nitrogen content.
For the purpose of relieving the time cost and inconformity in annotation, the authors use an articulatory features based mispronunciation detection system to give an Top-N feedback and use this feedback to assist manual annotation. As a result, the consistency rate of phoneme labels in proposed system increases from 80.7% to 92.48%. In addition, the time cost for annotating each sentence reduce from 10 to 3 minutes. The results indicate that proposed automatic annotation system is practical, and there is also a room for further improvement.
The granitoid rocks in the Xinbin-Weiziyu area, northern Liaoning Province, comprise tonalitictrondhjemitic gneisses and monzogranite-syenogranite plutons. To determine their formation ages and petrogenesis, zircon U-Pb-Hf isotopic analyses and whole-rock geochemical analyses are conducted on these granitoid rocks. LAICP-MS zircon U-Pb isotopic dating data reveal that the tonalitic and trondhjemitic gneisses emplaced at 2588±4 Ma (MSWD=1.3) and 2587±6 Ma (MSWD=1.8), respectively, and the monzogranite-syenogranite intrusions formed at 2555±4 Ma (MSWD=0.51). Whole-rock geochemistry and zircon Lu-Hf isotopes suggest that magmatic precursors of the tonalitic-trondhjemitic gneisses were derived from partial melting of subducted slabs and the magmas were contaminated by the mantle wedge materials during their ascent. Some of the monzogranitesyenogranite plutons were produced by partial melting of metagreywackes, whereas the others were generated by partial melting of a mixed source composed of metabasalts and metasedimentary rocks. Integrated with recent studies, the Neoarchean granitoid rocks in the Xinbin-Weiziyu area may have been generated under an active continental margin.
On the base of the 3D seismic profile interpretations, combined with the previous findings, geometry and tectonic evolution across and along the Laojunmiao break-thrust belt in the northern margin of the Northern Qilian belt are deciphered. The Laojunmiao belt is a bi-layer thrust system, consisting of a trishear faultpropagation fold system in the upper part, wedge-shaped thrust in the lower part. The Laojunmiao thrust system is linked with the NE-SW striking-slip 134 fault in the western segment, which forms a unified system of fracture on the Laojunmiao belt. Thrusting sheet above the hanging wall of the 134-Laojunmiao fault system is folded under nearly E-S compressive stress field, which results in the N-S striking folding to superpose on the Cenozoic bedding.
This paper proposes a method to construct Bilingual Movie Knowledge Graph (BMKG). The authors first builds Bilingual Movie Ontology (BMO) through a semi-automatic way, and aligns each data source with it in order to ensure semantic consistency of heterogeneous data sources. For entity linking, the proposed method makes best use of the field characteristics and calculate entity similarity based on both Word2Vec and TFIDF models, which greatly improve entity linking. For entity matching, a similarity flooding based algorithm is proposed, which utilizes the intrinsic links between the movie data sources, addressing the problem of similarity computation between cross-lingual entities. The experiment results show that the entity matching precision is over 90% when the threshold is above 0.75. In addition, a movie knowledge graph sharing platform is also built to provide open data access and query interface.