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Small object detection (SOD) in remote sensing images (RSIs) is a challenging task due to scale variation, severe occlusion, and complex backgrounds, often leading to high miss and false detection rates. To address these issues, this paper proposes a novel detection framework named HSF-YOLO, which is designed to jointly enhance feature encoding, attention interaction, and localization precision within the YOLOv8 backbone. Specifically, we introduce three tailored modules: Hybrid Atrous Enhanced Convolution (HAEC), a Spatial–Interactive–Shuffle attention module (C2f_SIS), and a Focal Gradient Refinement Loss (FGR-Loss). The HAEC module captures multi-scale semantic and fine-grained local information through parallel atrous and standard convolutions, thereby enhancing small object representation across scales. The C2f_SIS module fuses spatial and improved channel attention with a channel shuffle strategy to enhance feature interaction and suppress background noise. The FGR-Loss incorporates gradient-aware localization, focal weighting, and separation-aware constraints to improve regression accuracy and training robustness. Extensive experiments were conducted on three public remote sensing datasets. Compared with the baseline YOLOv8, HSF-YOLO improved mAP@0.5 and mAP@0.5:0.95 by 5.7% and 4.0% on the VisDrone2019 dataset, by 2.3% and 2.5% on the DIOR dataset, and by 2.3% and 2.1% on the NWPU VHR-10 dataset, respectively. These results confirm that HSF-YOLO is a unified and effective solution for small object detection in complex RSI scenarios, offering a good balance between accuracy and efficiency.

Rice blast is one of the most destructive diseases affecting rice worldwide. The adoption of host resistance has proven to be the most economical and effective approach to control rice blast. In recent years, sequence-specific nucleases (SSNs) have been demonstrated to be powerful tools for the improvement of crops via gene-specific genome editing, and CRISPR/Cas9 is thought to be the most effective SSN. Here, we report the improvement of rice blast resistance by engineering a CRISPR/Cas9 SSN (C-ERF922) targeting the OsERF922 gene in rice. Twenty-one C-ERF922-induced mutant plants (42.0%) were identified from 50 T0 transgenic plants. Sanger sequencing revealed that these plants harbored various insertion or deletion (InDel) mutations at the target site. We showed that all of the C-ERF922-induced allele mutations were transmitted to subsequent generations. Mutant plants harboring the desired gene modification but not containing the transferred DNA were obtained by segregation in the T1 and T2 generations. Six T2 homozygous mutant lines were further examined for a blast resistance phenotype and agronomic traits, such as plant height, flag leaf length and width, number of productive panicles, panicle length, number of grains per panicle, seed setting percentage and thousand seed weight. The results revealed that the number of blast lesions formed following pathogen infection was significantly decreased in all 6 mutant lines compared with wild-type plants at both the seedling and tillering stages. Furthermore, there were no significant differences between any of the 6 T2 mutant lines and the wild-type plants with regard to the agronomic traits tested. We also simultaneously targeted multiple sites within OsERF922 by using Cas9/Multi-target-sgRNAs (C-ERF922S1S2 and C-ERF922S1S2S3) to obtain plants harboring mutations at two or three sites. Our results indicate that gene modification via CRISPR/Cas9 is a useful approach for enhancing blast resistance in rice.

The near wake of a hemisphere immersed in a laminar boundary layer is studied utilizing time-resolved tomographic particle image velocimetry (TPIV). Focus is placed on the three-dimensional vortical structures and the formation details of hairpin vortices before the onset of transition. The three-dimensional instantaneous pressure field of the hemisphere wake is reconstructed for better understanding the flow mechanism. Experiments are carried out with Reynolds number $Re_{r}=1370$, based on the hemisphere radius $R$. Features of periodicity of the near wake are analysed using proper orthogonal decomposition and Fourier transformation. The velocity fluctuation in the wall-normal direction is shown to be crucial to the formation of hairpin vortices in the near wake. By investigating the transport of mass and vorticity, and the correlation between pressure and hairpin vortex strength, the formation mechanism is revealed clearly. Specifically, the main hairpin vortices (MHVs) are formed within the reaction of outer high-speed flow and near-wall flow. The formation of the head portion is followed by the leg portion formation. The shedding of the MHVs is highly correlated with the pressure, as well as the pressure gradient in the wall-normal direction. For the side hairpin vortices (SHVs), the leg portion is formed first, followed by the generation of the head portion thanks to induction of the re-oriented standing vortices. The generation of the SHVs can be regarded as the downstream bridging of the standing vortices, similar to the generation of hairpin vortices due to the connection of streamwise vortices in turbulent boundary layers.

Feature selection is an important task in big data analysis and information retrieval processing. It reduces the number of features by removing noise, extraneous data. In this paper, one feature subset selection algorithm based on damping oscillation theory and support vector machine classifier is proposed. This algorithm is called the Maximum Kendall coefficient Maximum Euclidean Distance Improved Gray Wolf Optimization algorithm (MKMDIGWO). In MKMDIGWO, first, a filter model based on Kendall coefficient and Euclidean distance is proposed, which is used to measure the correlation and redundancy of the candidate feature subset. Second, the wrapper model is an improved grey wolf optimization algorithm, in which its position update formula has been improved in order to achieve optimal results. Third, the filter model and the wrapper model are dynamically adjusted by the damping oscillation theory to achieve the effect of finding an optimal feature subset. Therefore, MKMDIGWO achieves both the efficiency of the filter model and the high precision of the wrapper model. Experimental results on five UCI public data sets and two microarray data sets have demonstrated the higher classification accuracy of the MKMDIGWO algorithm than that of other four state-of-the-art algorithms. The maximum ACC value of the MKMDIGWO algorithm is at least 0.5% higher than other algorithms on 10 data sets.

The Beishan orogen, a significant component of the southern Altaids, presents an opportunity for investigating the intracontinental deformation and exhumation history of the Altaids during the Mesozoic era. Although previous studies indicated that the Beishan orogen has experienced multiple reactivation since the late Mesozoic, the precise extent of these events remains poorly constrained. Here, we provide a comprehensive synthesis of field observations and apatite fission track (AFT) thermochronological dating throughout the Beishan orogen. Detailed field observations confirmed four major E-W trending thrusts in our study area. Based on the youngest truncated strata associated with the thrusts and previous dating results from neighboring regions, we propose that these thrust sheets likely developed in the late Middle Jurassic. AFT dating results from seven pre-Mesozoic granitoid samples and associated with thermal history modeling demonstrate that the Beishan orogen experienced a rapid basement cooling during the mid-Cretaceous (∼115-80 Ma). Moreover, a compilation of previously published and newly gained AFT data reveals a comparable mid-Cretaceous cooling event in other parts of Central Asia, such as Qilian Shan, Eastern Tianshan, and Altai-Sayan. This observation suggests that the mid-Cretaceous cooling event is more likely to be regional rather than localized. This mid-Cretaceous cooling pulse is interpreted as a tectonic exhumation controlled by boundary faults and related to the rotation of the Junggar and Tarim basins. These processes are linked to distant plate-margin events along the Eurasian continent.

Catalytic asymmetric synthesis of helically chiral molecules has remained an outstanding challenge and witnessed fairly limited progress in the past decades. Current methods to construct such compounds almost entirely rely on catalytic enantiocontrolled fused-ring system extension. Herein, we report a direct terminal peri -functionalization strategy, which allows for efficient assembling of 1,12-disubstituted [4]carbohelicenes via an organocatalyzed enantioselective amination reaction of 2-hydroxybenzo[ c ]phenanthrene derivates with diazodicarboxamides. The key feature of this approach is that the stereochemical information of the catalyst could be transferred into not only the helix sense but also the remote C-N axial chirality of the products, thus enabling the synthesis of [4]- and [5]helicenes with both structural diversity and stereochemical complexity in good efficiency and excellent enantiocontrol. Besides, the large-scale preparations and representative transformations of the helical products further demonstrate the practicality of this protocol. Moreover, DFT calculations reveal that both the hydrogen bonds and the C-H---π interactions between the substrates and catalyst contribute to the ideal stereochemical control. Current methods to construct helical chiral molecules for asymmetric catalysis almost entirely rely on catalytic enantiocontrolled fused-ring system extension. Herein, the authors report a direct terminal peri -functionalization strategy, which allows for efficient assembling of substituted carbohelicenes via an organocatalyzed enantioselective amination reaction.

The favorable mechanical property and regenerative capacity of bone graft are extremely important for the reconstruction of the large bone defect. Polyetheretherketone (PEEK) has tailored elastic modulus to natural cortical bone, while its application is limited by bio-inert surface. Tissue-engineered periosteum exhibits improved osteogenesis-inducing capacity. However, the present artificial periosteum is difficult to effectively anchor to bone grafts. The use of PEEK-based nanomembrane may be a promising candidate to integrate with PEEK bone graft without anchor problem, which has not been reported until now. In this work, a series of fluorinated PEEK polymers were successfully synthesized and electrospun into nanofibers. The chemical structure, morphology, thermal stability, wettability and mechanical strength of s-PEEK membranes were investigated. Then, a novel flexible nanocomposite membrane for tissue-engineered periosteum based on fibrous sulfonated PEEK (s-PEEK) and polycaprolactone (PCL) was prepared. The functional properties were evaluated accordingly. The s-PEEK/PCL composite membranes showed superior hydrophilic and better ductility than pure s-PEEK film. The capacity of protein adsorption was also evaluated, suggesting the elevated bioactivity of s-PEEK/PCL composite membranes. Finally, the composite membranes were successfully mineralized by a homogenous and thinner calcium phosphate layer, indicating its potential to improve the osteogenic response.

The spatial distribution and temporal variability of the Kuroshio Current (KC) was investigated with three moorings deployed at 122.7° E, 123° E, and 123.3° E along 18° N from January 2018 to the spring of 2020. It is shown that the core of the KC is located to the west of 122.7° E along 18° N. With the increase in longitude, the KC extended its vertical scale and attenuated its intensity gradually. The satellite data indicated that the KC was strongest in winter and spring, while it was weakest in autumn along 18° N. However, the seasonal cycle of the KC from mooring observations was atypical compared with that from the satellite data. The seasonal variation of the KC was not obvious in 2018, and a summer peak of KC occurred in 2019. The atypical seasonal variability of the KC was attributed to the strong intraseasonal signals generated by eddy activity. Eddies propagated from east and were enhanced to the west of 140° E, leading to the westward intensified intraseasonal signals. In addition, the intraseasonal signals varied interannually, that is why the variation of the KC in 2018 was quite different with that in 2019.

Textile technology shows great advantages in tissue engineering applications and it is a promising candidate for bone scaffolds fabrication. Composite fibers made from nano-hydroxyapatite (nHA) particles and polycaprolactone (PCL) were prepared by the melt spinning technology. nHA particles with different concentrations (1, 3, 5 and 7 wt%) were loaded into PCL fibers, and their influence on fiber morphological, thermal, mechanical and biological performance was evaluated. Results indicated that nHA particles were homogeneously distributed in PCL fibers. And nHA loading improved the break stress and initial modulus of pure PCL fibers, as well as thermal stability, which was confirmed by thermogravimetric analysis. Mineral deposition was also observed on fibers with nHA loading, which was favorable to bone scaffolds. Tubular meshes made by weft knitting proved the manufacturability of nHA/PCL composite fibers for further scaffold applications.

Vortex is the dominant flow structure in hydro-energy machinery, and its swirling features are mainly determined by the rigid rotation part of vorticity. In this study, the rigid vorticity transport equation is proposed based on the vorticity decomposition. The vortex spatial evolution is described by the stretching term RST, the dilatation term RDT, the Lamb term RCT and the viscous term RVT. The shape change of a vortex tube is mainly affected by RST and RDT, while vortex production and dissipation are mainly reflected by RCT and RVT. Compared with the traditional vorticity transport equation, this new theoretical tool can distinguish between rigid rotation and shearing motion of local fluids, and it can better reveal the intuitive evolution characteristics of vortical structures. Two cases with clear engineering demands are analysed by using the transport equation, and the results show that it can provide a practical method for the analysis and control of vortical flows in hydro-energy machinery.