Search

Tropical cyclone rapid intensification (RI) prediction still remains a big international challenge in numerical weather prediction. Hurricane Matthew (2016) underwent extreme and non-classic RI, intensifying from a Category 1 storm to a Category 5 hurricane within 24 h under a strong vertical shear environment. However, most models failed to capture this RI, and limited or no inner core, and outflow observations were assimilated in the NWS operational HWRF Model before the onset of RI for Matthew (2016). The goals of the study are to (1) explore the best way to assimilate the High-Density Observations (HDOB, including FL and SFMR) and AMV data; (2) study the impact of assimilating these observations on the analysis of both the inner-core and outflow structures; and (3) examine the impact of assimilating these data on the prediction of RI for Matthew. The main results are as follows: (1) With proper pre-processing of the HDOB observations and by using a 4DEnVar method, the inner-core structure analysis was improved. And the RI prediction is more consistent with the best track without spin-down for the first 24 h. Assimilating CIMMS AMV observations on top of the HDOB observations further improves both the track and intensity forecasts. Specifically, both the magnitude and timing of the peak intensity are further improved. (2) Diagnostics are conducted to understand how the assimilation of these different types of observations impacts RI prediction. Without assimilating HODB and AMV data, baseline experimentover-predict the intensification rate during the first 18 h, but under-predict RI after 18 h. However, the assimilation of FL and SFMR and CIMMS AMV correctly weakens the upper-level outflow and improves the shear-relative structure of the inner-core vortex, such as reducing the low-level moisture in the downshear left quadrant. The deep convection on the downshear side is weaker than baseline for the first 18 h but keeps enhancing, later moving cyclonically to the USL quadrant, and then causes more subsidence warming, maximizing in the USL quadrant and the maximum wind increases faster. Moreover, the rapid intensification rate is much more consistent with the best track and the forecast skill of RI is improved. Therefore, 4DEnVar assimilation with proper pre-processing of the high-density observations can indeed correct the shear-relative moisture and structural distributions of both the inner core and environment for TCs imbedded in the stronger shear, which is important for shear-TC RI prediction. [ABSTRACT FROM AUTHOR]

The impact of assimilating ground‐based radar reflectivity on the rainband structure and secondary eyewall formation (SEF) of Hurricane Matthew (2016) is investigated within the framework of the Hurricane Weather Research and Forecasting model and its hybrid three‐dimensional ensemble‐variational data assimilation (DA) system. Compared to the control experiment (no radar reflectivity DA), the radar reflectivity DA experiment shows a clear signal of concentric eyewall and eyewall replacement cycle. Results demonstrate that radar reflectivity DA improves the stratiform rainband analysis, resulting in the mid‐level cooling associated with mesoscale descending inflow (MDI). The MDI further contributes to the low‐level acceleration maximum with boundary layer dynamics and triggers new convective updrafts in the SEF region. Momentum budget analysis also suggests that the mean vertical advection of absolute angular momentum plays an important role in the local momentum tendency in the SEF region in Hurricane Matthew (2016). Plain Language Summary: The impact of assimilating radar reflectivity on the secondary eyewall formation (SEF) of Hurricane Matthew (2016) is investigated within the framework of the Hurricane Weather Research and Forecasting model and its hybrid three‐dimensional ensemble‐variational data assimilation (DA) system. Compared to the control experiment (no radar reflectivity DA), the radar reflectivity DA experiment shows a clear signal of secondary eyewall and eyewall replacement cycle. Results demonstrate that radar reflectivity DA improves the stratiform rainband analysis, resulting in mesoscale descending inflow (MDI). The MDI further contributes to the low‐level tangential wind increase in boundary layer and triggers new convective updrafts in the SEF region. Results also suggests that the mean vertical advection of absolute angular momentum plays an important role in the local momentum tendency in the SEF region in Hurricane Matthew (2016). Key Points: Utilizing radar reflectivity data assimilation enhances the analysis of stratiform rainbands associated with mesoscale descending inflow (MDI)Momentum budget analysis indicates that the MDI brings high angular momentum to the boundary layer through the mean vertical advection termThe high angular momentum by the MDI contributes to the low‐level acceleration maximum in the secondary eyewall formation region [ABSTRACT FROM AUTHOR]

Forecast sensitivity to observation (FSO) methods have become increasingly popular over the past two decades, providing the ability to quantify the impacts of various observing systems on forecasts without having to conduct costly data denial experiments. While adjoint- and ensemble-based FSO are employed in many global operational systems, their use for regional convection-allowing data assimilation (DA) and forecast systems have not been fully examined. In this study, ensemble FSO (EFSO) is explored for high-frequency convective-scale DA for a severe weather case study over the Dallas–Fort Worth testbed. This testbed, originally established by the Collaborative Adaptive Sensing of the Atmosphere (CASA) project, aims to improve high-resolution DA systems by assimilating a variety of existing state and regional mesoscale observing systems to fill gaps of conventional observing networks. This study utilizes EFSO to estimate relative impacts of nonconventional surface observations against conventional observations, and further incorporates assimilated radar observations into EFSO. Results show that, when applying advected localization and a neighborhood upscale averaging technique, EFSO estimates remain correlated and skillful with the actual error reduction of all assimilated observations for the duration of 2-h forecasts. The ability for EFSO to verify against other metrics (surface T, u, υ, q) beside energy norms is also demonstrated, emphasizing that EFSO can be used to evaluate impacts of specific parts of the forecast system rather than integrated quantities. Partitioned EFSO revealed that while conventional and radar observations contributed to most of the total energy, nonconventional observations contributed a significant percentage (up to 25%) of the total impact to surface thermodynamic fields. [ABSTRACT FROM AUTHOR]

The Gridpoint Statistical Interpolation (GSI)-based four- and three-dimensional ensemble–variational (4DEnVar and 3DEnVar) methods are compared as a smoother and a filter, respectively, for rapidly changing storms using the convective-scale direct radar reflectivity data assimilation (DA) framework. Two sets of experiments with varying DA window lengths (WLs; 20, 40, 100, and 160 min) and radar observation intervals (RIs; 20 and 5 min) are conducted for the 5–6 May 2019 case. The RI determines the temporal resolution of ensemble perturbations for the smoother and the DA interval for the filter spanning the WL. For experiments with a 20-min RI, evaluations suggest that the filter and the smoother have comparable performance with a 20-min WL; however, extending the WL results in the outperformance of the filter over the smoother. Diagnostics reveal that the degradation of the smoother is attributed to the increased degree of nonlinearity and the issue of time-independent localization as the WL extends. Evaluations for experiments with different RIs under the same WL indicate that the outperformance of the filter over the smoother diminishes for most forecast hours at thresholds of 30 dBZ and above when shortening the RI. Diagnostics show that more frequent interruptions of the model introduce model imbalance for the filter, and the increased temporal resolution of ensemble perturbations enhances the degree of nonlinearity for the smoother. The impact of model imbalance on the filter overwhelms the enhanced nonlinearity on the smoother as the RI reduces. Significance Statement: The background uncertainties of rapidly changing storms suffer from fast error growth and high degrees of nonlinearities during the data assimilation (DA) period. Two variants of the ensemble-based DA method can account for such temporal evolution. The smoother uses background ensemble from multiple observation times over an assimilation period to estimate the propagation of statistics. The filter frequently calculates the statistics at multiple observation times over the same period. Current comparisons of the smoother and the filter were mostly performed using simple models; however, unknowns remain for convection-allowing forecasts with additional complexities. This study compares the filter and the smoother for the convective-scale analysis and prediction using a real-data study and finds that the comparison varies with the assimilation period and the observation interval. [ABSTRACT FROM AUTHOR]

[Display omitted] • The CFD simulation determined that 15 min/h was the best stirring time. • Explore the combined effects of stirring and net energy output. • Hydrogen nutrition is the main methanogenic pathway. • Metabolic analysis showed that the methane production pathway was enhanced. This study optimized the stirring time of cattle manure (CM)-corn stover (CS) co-digestion to improve Anaerobic digestion (AD) performance. The results showed that the experimental (T2) with the optimum stirring time (15 min/h) determined by computational fluid dynamics (CFD) simulation achieved the highest cumulative methane yield of 224.17 mL/g. Compared to continuous stirring (T1, 60 min/h) and intermittent stirring (T3, 5 min/h), T2 increased the cumulative methane yield by 18.65 % and 7.11 %, respectively. Additionally, microbial community analysis indicated that the relative abundance of the predominant methanogen Methanosarcina in T2 was increased by 9.56 % and 26.14 % compared to T1 and T3, respectively. Functional prediction by PICRUSt2 revealed that T2 enhanced the hydrogenotrophic methanogenesis pathway, which played a major role in the methanogenesis pathway. In summary, this study provides insights for optimizing the stirring time of AD and plays an important role in improving the methane yield efficiency and reducing energy consumption of biogas projects. [ABSTRACT FROM AUTHOR]

Supercapacitors have immense promise in the field of energy storage, and the choice of electrode materials is of utmost importance. In this study, we have developed a ternary composite electrode material consisting of poly(3,4-ethylenedioxythiophene)/ Ti 3 C 2 T x /Co 3 S 2 (PEDOT/Ti 3 C 2 T x /Co 3 S 2) using a solid-state heating method, without the need for an oxidant. Interestingly, we observed that the exclusion of an oxidant such as ferric chloride has proven advantageous in preventing the oxidation of Ti 3 C 2 T x nanosheets. Moreover, the synergistic effect between Co 3 S 2 and Ti 3 C 2 T x nanosheets enhances the structural stability of the composite material during the electrochemical process. The presence of PEDOT on the surface of Ti 3 C 2 T x /Co 3 S 2 acts as a reinforcing agent, effectively preventing the self-stacking of Ti 3 C 2 T x and thereby increasing the specific surface area and conductivity of the resulting composite. Furthermore, the synergistic effects between different phases in the composite material can accelerate the interface charge transfer in the electrochemical redox process. Electrochemical results show that the gravimetric capacitance of the PEDOT/Ti 3 C 2 T x / Co 3 S 2 is 1135.6 F g-1. The quasi-solid supercapacitor assembled by combining the PEDOT/Ti 3 C 2 T x /Co 3 S 2 with alkaline hydrogel electrolyte (PVA/KOH) exhibits an energy density of 35.94 Wh kg-1 and a power density of 750.05 W kg-1 at 4 A g-1. After 20,000 cycles, the capacitance retention rate is 110.89%, and the Coulomb efficiency is 95.37%. [Display omitted] • PEDOT/Ti 3 C 2 T x /Co 3 S 2 composite is prepared by solid-phase heating method. • The interaction between Co 3 S 2 and Ti 3 C 2 T x enhances the structural stability of composite in electrochemical process. • The PEDOT can be benefit for the increasing of specific surface area and conductivity of composite. • The composite has a high specific capacitance of 1135.6 F g-1 and a cycle stability of up to 110.89%. [ABSTRACT FROM AUTHOR]

• A strategy for chemicalome and associated metabolome profiling of Chinese patent drug was performed. • Chemical profiling of Huanghou antidiarrhea dropping pills was firstly analyzed by UHPLC-QTOF-MS/MS. • A prototypes-metabolites network of Huanghou antidiarrhea dropping pills was established by biotransformation pathways. • Tissue distributions of active ingredients were explored in colon, liver, heart, spleen, lung and kidney. Huanghou antidiarrhea dropping pills (HADP) is an efficient Chinese patent drug that is clinically used to treat diarrhea. However, its functional materials remain unclear due to the characteristics of traditional Chinese medicine, which is a multi-component and multi-target complex system. In this study, we investigated the intrinsic chemical components and combined with in vivo metabolism to reveal the functional material basis of HADP. Spectral behavior (accurate molecular weight and secondary fragmentation) and chromatographic behavior (retention time) were key criterions that throughout the whole research of components identification, prototypes screening, and tissue distribution. Mass defect filter (MDF), characteristic product ion filter (PIF), and neutral loss filter (NLF) were other three criterions for metabolites searching. Consequently, a total of 102 components in HADP, including alkaloids, lignans, lactones, gingerols, and alkaloid complexes were identified or tentatively characterized. About 39 metabolites that related to 37 prototypes were calculated and matched in bio-samples. Among them, 14 prototypes and 18 metabolites were detected distribution in colon, liver, heart, spleen, lung or kidney. This study provides a systematic investigation into the metabolism of HADP and offers effective analytical strategies for the characterization of compounds and metabolites in Chinese patent drugs. [ABSTRACT FROM AUTHOR]

Supercapacitors play a crucial role in energy storage applications due to their high energy and power densities. In this context, synthesizing composites such as: poly(3,4propylenedioxythiophene)/CoNi 2 S 4 @hollow carbon sphere (PProDOT/CoNi 2 S 4 @HCS) through solid-state thermal polymerization and hydrothermal ion exchange has gained significant attention. The PProDOT/CoNi 2 S 4 @HCS composite exhibits exceptional electrochemical performance, including a high specific capacitance of 1054 C g−1 and an initial capacity retention rate of 83.3% at 20 A g−1. This signifies that the composite can effectively store and deliver electrical energy. The composite possesses a three-dimensional core-shell structure, wherein HCS acts as a carbon-based substrate that prevents the aggregation of CoNi 2 S 4 nanoparticles. Simultaneously, the PProDOT film ensures the structural integrity of CoNi 2 S 4 and facilitates efficient electron/ion transfer within the composite. Furthermore, researchers have assembled a quasi-solid-state supercapacitor using the PProDOT/CoNi 2 S 4 @HCS composite and a gel electrolyte composed of polyvinyl alcohol/sulfonated cellulose/gelatin (PVA/sCMC/GEL/KOH). This supercapacitor demonstrates outstanding characteristics, such as a high energy density of 85.3 Wh kg−1, a high power density of 7957 W kg−1, and a capacity retention rate of 87.56% after 15,000 cycles at 4 A g−1. These results indicate that the composite-based supercapacitor can provide long-term stability and reliable performance under demanding operating conditions. [Display omitted] • A ternary core-shell material with ultra-high capacity retention at high current density has been realized. • The conductive polymer coating was prepared by in-situ solid-state thermal polymerization. • Designed a gel electrolyte with high ionic conductivity. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new variable intermittent stirring strategy was proposed. • Compare different stirring strategies in anaerobic digestion. • An energy output index optimization stirring strategy was proposed. • The optimal stirring strategy was determined. The stirring strategy has a significant effect on the efficiency of anaerobic digestion (AD). In this study, the suspension velocity of multi-layer blade particles was characterized based on CFD simulation, and a variable frequency intermittent stirring strategy was proposed to study the stirring effect and mixing energy consumption. Firstly, the fermentation cycle was divided into three parts, and three stirring speeds and mixing times were set for each part to carry out an orthogonal combination test. Taking methane production and mixing energy consumption as optimization indexes, a net energy output equation was established to optimize the new stirring strategy. The results showed that the new variable frequency intermittent stirring strategy could effectively improve digestion efficiency. This provides a theoretical basis for setting a stirring strategy in a biogas project. [ABSTRACT FROM AUTHOR]

In the field of multimodal sentiment analysis, it is an important research task to fully extract modal features and perform efficient fusion. In response to the problems of insufficient semantic information and poor cross-modal fusion effect of traditional sentiment classification models, this paper proposes a composite hierarchical feature fusion method combined with prior knowledge. Firstly, the ALBERT (A Lite BERT) model and the improved ResNet model are constructed for feature extraction of text and image, respectively, and high-dimensional feature vectors are obtained. Secondly, to solve the problem of insufficient semantic information expression in cross-scene, a prior knowledge enhancement model is proposed to enrich the data characteristics of each modality. Finally, to solve the problem of poor cross-modal fusion effect, a composite hierarchical fusion model is proposed, which combines the temporal convolutional network and the attention mechanism to fuse the sequence features of each modality information and realizes the information interaction between different modalities. Experiments on MVSA-Single and MVSA-Multi datasets show that the proposed model is superior to a series of comparison models and has good adaptability in new scenarios. [ABSTRACT FROM AUTHOR]

Simple Summary: There have been few studies on the use of umbilical cord mesenchymal stem cells as donor nuclei in nuclear transplantation, despite their advantages of less reprogramming difficulty and shorter reprogramming distance. This study compared differences at the chromatin level, the level of differentially expressed genes, the level of histone modifications, and the level of DNA methylation in eight-cell embryos after using umbilical cord mesenchymal stem cells and fibroblasts as nucleus donors, using a single-cell transcriptome. Oocytes are efficient at reprogramming terminally differentiated cells to a totipotent state. Nuclear transfer techniques can exploit this property to produce cloned animals. However, the overall efficiency is low. The use of umbilical cord mesenchymal stem cells (UC-MSCs) as donor nuclei may increase blastocyst rates, but the exact reasons for this remain unexplored. A single-cell transcriptomic approach was used to map the transcriptome profiles of eight-cell embryos that were in vitro-fertilized and handmade-cloned using umbilical cord mesenchymal stem cells and fibroblasts as nuclear donors. Differences were examined at the chromatin level, the level of differentially expressed genes, the level of histone modifications and the level of DNA methylation. This research provides critical information regarding the use of UC-MSCs as a preferred donor nucleus for nuclear transfer techniques. It also offers unique insights into the mechanism of cellular reprogramming. [ABSTRACT FROM AUTHOR]

Simple Summary: Vitrification causes oxidative stress and organelle damage in oocytes. The results of this study reveal that Mito-TEMPO can efficaciously improve the oxidative stress injury of vitrified oocytes by recovering mitochondrial function via the mitochondrial respiratory chain. In this experiment, we supplemented GV-stage oocyte vitrified thawing and in vitro maturation with Mito-TEMPO to observe its effects on sheep oocyte vitrification. It was shown that Mito-TEMPO could not only rescue the apoptosis and mitochondrial dysfunction of vitrified oocytes but also regulate their intracellular Ca2+ homeostasis and ATP content, as well as provide strong antioxidant properties. Our analysis of single-cell transcriptomes revealed that the positive impact of Mito-TEMPO on vitrified oocytes is facilitated by the respiratory chain, which indicates that Mito-TEMPO may be a promising mitochondria-targeted antioxidant to enhance vitrified oocyte quality. Vitrification is a crucial method for preserving animal germ cells. Considering the increased oxidative stress and organelle damage incurred, it is still necessary to make the process more efficient for oocytes. As the energy source of oocytes, mitochondria are the most abundant organelle in oocytes and play a crucial role in their maturation. Here, we found that Mito-TEMPO, a mitochondria-targeted antioxidant, could efficaciously improve the oxidative stress injury of vitrified oocytes by recovering mitochondrial function via the mitochondrial respiratory chain. It was observed that Mito-TEMPO not only improves oocyte viability and meiosis but also maintains spindle structure. A subsequent study indicated that Mito-TEMPO effectively rescued mitochondrial dysfunction and attenuated vitrification-induced oxidative stress. Further investigation revealed that Mito-TEMPO regulates vitrified oocytes' intracellular Ca2+ homeostasis and ATP content and provides strong antioxidant properties. Additionally, an analysis of the transcriptome at the single-cell level revealed that the respiratory chain mediates the beneficial effect of Mito-TEMPO on vitrified oocytes. Overall, our findings indicate that supplementing oocytes with Mito-TEMPO is an effective method to shield them from the damage caused by vitrification. In addition, the beneficial effects of Mito-TEMPO on vitrified sheep oocytes could inspire further investigations of the principles underlying oocyte cryobiology in other animals. [ABSTRACT FROM AUTHOR]