Lithospheric subduction prior to the assembly of the South China and North China blocks is traditionally considered to be directed northward. However, some critical geological and geochemical data ...cannot be reconciled with this northward subduction. This paper presents new lines of evidence against the traditional models and proposes a new and revolutionary tectonic model to explain the distribution and exhumation of high pressure (HP)-ultrahigh pressure (UHP) metamorphic rocks of the Dabie-Sulu Belt. We emphasize the following: 1) The Triassic tectonic environment of the southern margin of the North China Block was passive, not active, based on the stratigraphy; 2) In the southern margin of the North China Block no arc magmatism was recorded. 3) Many Paleoproterozoic slices of Jiaobei affinity of the Jiao-Liao-Ji Belt in the North China Block were located in the Triassic Sulu Orogen. 4) Many 1.85Ga metamorphic zircons are preserved in the Dabie-Sulu high pressure-ultra-high pressure (HP-UHP) metamorphic rocks. 5) The geometric asymmetry of many structural patterns in the HP-UHP slices indicates top-to-the northwest thrusting during the exhumation of HP-UHP slices. 6) Blueschists occur in the south of the UHP eclogite slices. 7) In the eastern segment of the North Qinling Orogen, no components with an affinity of the South China Block have been found. Along the Shangdan Suture of the Qinling Orogen has been recorded an apparent northward subduction. We consider that the suture is just a lateral subduction zone rather than a major collisional zone. Along the Shangdan Suture, the rarity of I-type plutonism can be attributed to a transform-type continental margin. The Bureya-Jiamusi-Khanka Block has an affinity to the South China Block based on its similarity regarding the Paleozoic history of deformation and Triassic blueschist metamorphic facies metamorphism. The Bureya-Jiamusi-Khanka Block could be the northern extension of the Dabie-Sulu Belt, and this gigantic belt could be interpreted as an orocline related to the southeastward subduction of the North China Block beneath the Greater South China Block.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Highly specific Cas9 nucleases derived from SpCas9 are valuable tools for genome editing, but their wide applications are hampered by a lack of knowledge governing guide RNA (gRNA) activity. Here, we ...perform a genome-scale screen to measure gRNA activity for two highly specific SpCas9 variants (eSpCas9(1.1) and SpCas9-HF1) and wild-type SpCas9 (WT-SpCas9) in human cells, and obtain indel rates of over 50,000 gRNAs for each nuclease, covering ~20,000 genes. We evaluate the contribution of 1,031 features to gRNA activity and develope models for activity prediction. Our data reveals that a combination of RNN with important biological features outperforms other models for activity prediction. We further demonstrate that our model outperforms other popular gRNA design tools. Finally, we develop an online design tool DeepHF for the three Cas9 nucleases. The database, as well as the designer tool, is freely accessible via a web server, http://www.DeepHF.com/ .
This paper is an overview of bibliometrics, a subfield of library and information science. It briefly explains what bibliometrics is and why it is important in research evaluation and impact ...analysis. It summarizes the latest development and trends over the past decade. Three major trends are identified and discussed. They are alternative metrics, responsible use of bibliometrics and responsible research evaluation movement, and application of artificial intelligence (AI) and machine learning in bibliometrics practice.
The viscosity structure of Earth's mantle, even the 1‐D radial viscosity profile, remains not well constrained. The dynamics of the subducting slabs is strongly affected by, and can be used to ...constrain, the viscosity structure of the mantle. Here, we perform fully dynamic, self‐consistent mantle convection models to study the dynamics of subducted slabs in the deep mantle. We use a statistical analysis approach to quantify how the depth distribution of flat‐lying slabs is affected by the depth‐dependence of mantle viscosity. We find that, for cases in which the viscosity increases at 660 km depth, whether sharply or gradually, flat‐lying slabs preferentially occur above this depth, and importantly, up to ∼30% of the subducted slabs previously flatted at this depth later sink to the deep lower mantle and maintain a flat‐lying morphology. The frequency of (or the probability to have) flat‐lying slabs at ∼1,000 km depth in these cases is similar to cases in which the viscosity jump occurs at 1,000 km depth. Therefore, to explain the presence of flat‐lying slabs at ∼1,000 km depth for the Earth does not require a viscosity jump at this depth. In contrast, a viscosity jump merely occurring at ∼1,000 km depth causes a lack of flat‐lying slabs in the uppermost lower mantle at ∼700–900 km depth and is inconsistent with seismic observations. The presence of flat‐lying slab materials in the Earth's uppermost lower mantle requires a viscosity increase at 660 km depth.
Plain Language Summary
Conventionally, a stepwise mantle viscosity jump is often modeled at 660 km depth where the endothermic phase transition occurs. However, some recent studies argued that the viscosity may increase at deeper depths of ∼1,000 km. Here, dynamically self‐consistent mantle convection models are performed to investigate the effect of the depth‐dependent mantle viscosity structure on slab morphologies. We quantify the statistics for the depth distribution of flat‐lying slabs with subducted slabs freely generated as a form of thermal boundary layer instabilities in mantle convection models. The models show that a stepwise viscosity increase at ∼1,000 km depth results in the absence of flat‐lying slabs at intermediate depths of 700–900 km below the transition zone. This is inconsistent with seismic tomography observations which indicate significant flat‐lying slab materials at ∼700–900 km depths. The viscosity increase at 660 km depth is therefore essential to cause flat‐lying slabs in the uppermost lower mantle.
Key Points
A statistical analysis is introduced to study the probability of slab stagnation events in fully dynamic, self‐consistent convection models
A viscosity jump at either 660 or 1,000 km depth causes similar frequency of flat‐lying slabs at ∼1,000 km depth
A viscosity jump at 1,000 km depth alone causes a lack of flat‐lying slabs in the uppermost lower mantle that is inconsistent with observations
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Compact CRISPR/Cas9 systems that can be packaged into an adeno-associated virus (AAV) hold great promise for gene therapy. Unfortunately, currently available small Cas9 nucleases either display low ...activity or require a long protospacer adjacent motif (PAM) sequence, limiting their extensive applications. Here, we screened a panel of Cas9 nucleases and identified a small Cas9 ortholog from Staphylococcus auricularis (SauriCas9), which recognizes a simple NNGG PAM, displays high activity for genome editing, and is compact enough to be packaged into an AAV for genome editing. Moreover, the conversion of adenine and cytosine bases can be achieved by fusing SauriCas9 to the cytidine and adenine deaminase. Therefore, SauriCas9 holds great potential for both basic research and clinical applications.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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•ARG richness and abundance in waters increased from rural to urban regions.•ARGs profiles showed a temporal stability in downstream waters over five years.•Deterministic and ...stochastic processes mainly shaped ARGs and OTUs, respectively.•Bacterial function and taxonomy community were decoupled in urbanizing watershed.•Progressive urbanization promotes the enrichment and stability of ARGs in waters.
Although the occurrence and distribution of antibiotic resistance genes (ARGs) in various aquatic ecosystems are well explored, understanding of the ecological processes and mechanisms governing the composition and dynamics of bacterial ARGs still remains limited across space and time. Here, we used high-throughput approaches to detect spatial patterns of bacterial ARGs and operational taxonomic units (OTUs) in an urbanizing subtropical watershed, Xiamen, southeast China over a five-year period. At watershed scale, the OTU profiles were undergoing a directional change, but the ARG profiles showed a high stability or stochastic change over time. Compared with the upstream and midstream, the richness, absolute abundance, normalized abundance and diversity of ARGs were significantly higher in the downstream waters. Our results revealed a clear rural-urban disparity in ARG and OTU profiles which were mainly governed by deterministic and stochastic assembly processes, respectively. With the increase of urban building area along the river, the ecological processes of ARG profiles shifted from stochastic to deterministic. In downstream waters, the bacterial ARG profiles were much more stable than bacterial OTUs. Further, our results indicated that both human-dominated environment (e.g., land use) and mobile genetic elements (MGEs) played an important role in shaping the ARG profiles and dynamics. Overall, this was a response to spatially extensive human-landscape interactions that included urban development in the river downstream region, which were common across subtropical coastal cities of China and can alter the ARG profile dynamics along rural-urban gradient. Therefore, watershed management actions aiming at reducing threats posed by ARGs in urbanizing watershed should first consider the surrounding urbanization level and the mode and intensity of human activity. Our findings also imply that due to the decoupling of bacterial function and taxonomy, both aspects should be studied separately.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Electrocatalytic oxidation (ECO) has attracted attention because of its high efficiency and environmental friendliness in water treatment. The preparation of anodes with high catalytic activity and ...long service lifetimes is a core part of electrocatalytic oxidation technology. Here, porous Ti/RuO2-IrO2@Pt, Ti/RuO2-TiO2@Pt, and Ti/Y2O3-RuO2-TiO2@Pt anodes were fabricated by means of modified micro-emulsion and vacuum impregnation methods with high porosity titanium plates as substrates. The scanning electron microscopy (SEM) images showed that RuO2-IrO2@Pt, RuO2-TiO2@Pt, and Y2O3-RuO2-TiO2@Pt nanoparticles were coated on the inner surface of the as-prepared anodes to form the active layer. Electrochemical analysis revealed that the high porosity substrate could result in a large electrochemically active area, and a long service life (60 h at 2 A cm−2 current density, 1 mol L−1 H2SO4 as the electrolyte, and 40 °C). The degradation experiments conducted on tetracycline hydrochloride (TC) showed that the porous Ti/Y2O3-RuO2-TiO2@Pt had the highest degradation efficiency for tetracycline, reaching 100% removal in 10 min with the lowest energy consumption of 167 kWh kg−1 TOC. The reaction was consistent with the pseudo-primary kinetics results with a k value of 0.5480 mol L−1 s−1, which was 16 times higher than that of the commercial Ti/RuO2-IrO2 electrode. The fluorospectrophotometry studies verified that the degradation and mineralization of tetracycline were mainly ascribed to the •OH generated in the electrocatalytic oxidation process. This study thus presents a series of alternative anodes for future industrial wastewater treatment.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
This study introduces a simultaneous multiscale data assimilation method by implementing model space spatial scale‐dependent localization (SDL) and variable‐dependent localization (VDL) within an ...ensemble variational system. This method updates all resolved scales by assimilating all observations at once. The impact of such an approach is examined by a series of radar data assimilation experiments. Single‐observation experiments show that SDL concurrently and more properly updates the storm and its ambient environments compared to a traditional single scale localization (SSL) for radar data assimilation. Including VDL on top of SDL (SDLVDL) realistically decreases the spatial coverage and intensity of moisture increments compared to SDL. Comparisons are then performed on the analyses and forecasts of the 8 May 2003 Oklahoma City supercell storm. Results show that SDL improves the analyses and forecasts during the data assimilation cycling by producing more realistic enhanced low‐level convergences than SSL. SDLVDL obtains more accurate analyses and subsequent forecasts for moisture than SDL. SDLVDL yields the best performance in reflectivity forecasts and storm maintenance. Compared to SSL, SDL has higher forecast skills before 2230 UTC and produces degraded forecasts in the later lead time.
Plain Language Summary
Convection‐allowing numerical weather prediction models resolve atmospheric flows at a wide range of scales. Therefore an effective data assimilation method is required to properly update all resolved scales. This study introduces and describes an ensemble based simultaneous multiscale data assimilation method by utilizing a scale‐dependent and variable‐dependent localization (VDL) method in the model state space. This approach corrects storms and corresponding larger scale environments concurrently. Results and diagnostics from a tornadic supercell case study assimilating radar observations show that the proposed multiscale approach improves the analyses and the earlier forecasts compared to the traditional single‐scale method. Further applying a VDL method in the multiscale approach yields the best forecast performance during the entire forecast period.
Key Points
This study introduces a simultaneous multiscale data assimilation method using spatial scale‐dependent and variable‐dependent localization (VDL)
The scale‐dependent method concurrently updates storm and its ambient environments compared to a traditional single scale method
Further applying VDL is beneficial in the analysis and forecast of a tornadic supercell
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
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