Accurate identification of potentially toxic element (PTE) sources is crucial for effective risk mitigation; however, the complex solubility of trace elements hinders such identification. Here, levels of PTEs in the dust of 105 leaf samples from 21 sites in urban Guiyang (China) were measured and positive matrix factorization was applied to help identify PTE sources. These results were validated through correlating PTE concentrations with the land-use areas surrounding the sample sites. Ni and As in the leaf dust were linked to the cleanest conditions, followed by Cr. Conversely, Zn, Cu, Cd and Pb were associated with higher pollution levels. Three primary sources of PTEs were identified, with traffic-agriculture emissions being the largest contributor at 40.42%. Natural sources followed closely at 39.41%, while industrial processes accounted for the remaining 20.17%. High-pollution areas were clustered around traffic hubs, where frequent vehicle idling and acceleration increased emissions. As traffic emission was a major source of atmospheric pollution, targeted flow optimization is needed to reduce risks of human exposure.

This article tries to map the state of civic engagement in social governance at local level in China. Using case studies in Hangzhou, we find that civic engagement in China has not increased responsiveness to citizens’ appeals as predicted in democracy theories. In contrast, civic engagement degrades to a powerful tool for the government to rule the people, which we call the “alienation of civic engagement.” Institutional Isomorphism theory is evoked to explain this phenomenon. Based on the strength of regime stability and responsiveness to citizens’ appeals, civic engagement is categorized into four types: ceremonial civic engagement, substantial civic engagement, absorptive civic engagement, and propagandistic civic engagement. We show the discourses, participation behaviors, and participation outcomes of each type of civic engagement. We also demonstrate how the authoritarian government developed strategies for each type of civic engagement.

Ionic surfactants are commonly employed to modify the rheological properties of fluids, particularly in terms of surface viscoelasticity. Concurrently, external electric fields can significantly impact the dynamics of liquid threads. A key question is how ionic surfactants affect the dynamic behaviour of threads in the presence of an electric field? To investigate this, a one-dimensional model of a liquid thread coated with surfactants within a radial electric field is established, employing the long-wave approximation. We systematically investigate the effects of dimensionless parameters associated with the surfactants, including surfactant concentration, dilatational Boussinesq number ${\textit{Bo}}_{\kappa \infty }$ and shear Boussinesq number ${\textit{Bo}}_{\mu \infty }$. The results indicate that increasing the surfactant concentration and the two Boussinesq numbers reduces both the maximum growth rate and the dominant wavenumber. In addition, both the electric field and surfactants mitigate the breakup of the liquid thread and the formation of satellite droplets. At low applied electric potentials, the surface viscosity induced by surfactants predominantly governs this suppression. Surface viscosity suppresses the formation of satellite droplets by maintaining the neck point at the centre of the liquid thread within a single disturbance wavelength. When the applied potential is high, the electric stress has two main effects: the external electric field exerts a normal pressure on the liquid thread surface, suppressing satellite droplet formation, while the internal electric field inhibits liquid drainage. Surface viscosity further stabilizes the system by suppressing flow dynamics during this process.

Evidence regarding the association between dietary choline intake and mortality in individuals with diabetes remains limited. This study aimed to evaluate the relationship between dietary choline intake and all-cause, CVD and cancer-related mortality among adults with diabetes. A total of 4712 participants with diabetes were included from the National Health and Nutrition Examination Survey 2007–2018 cycles. Dietary choline intake was estimated using two 24-h dietary recalls, and mortality outcomes were ascertained via linkage to National Death Index records through 31 December 2019. Cox proportional hazards models and Kaplan-Meier analyses were employed to assess the associations between choline intake and mortality. Restricted cubic spline models were used to examine potential non-linear relationships, and threshold analyses were conducted to identify inflection points. Over a median follow-up of 6·42 years, 805 deaths were documented, including 267 from CVD and 126 from cancer. A U-shaped association was observed between dietary choline intake and all-cause mortality (Pfor non-linearity < 0·0001). Compared with the lowest quartile, multivariable-adjusted hazard ratios for all-cause mortality were 0·64 (95 % CI 0·47, 0·88) for the second quartile, 0·59 (0·43, 0·82) for the third and 0·69 (0·43, 1·09) for the highest quartile. No significant associations were found between choline intake and either CVD or cancer mortality. These findings indicate a U-shaped relationship between dietary choline intake and all-cause mortality in individuals with diabetes, with intakes between 286·77 and 538·86 mg/d associated with the lowest risk – providing potential implications for dietary guidance in diabetes management.

African swine fever (ASF) is a highly contagious animal disease caused by African swine fever virus (ASFV). It is listed by the World Organization for Animal Health (WOAH) as an animal disease subject to statutory reporting. ASFV, a large, enveloped double-stranded DNA virus with high genomic complexity, exhibits a case fatality rate of up to 100%, posing a significant threat to the global pig industry and food safety. To date, the absence of a safe commercial ASFV vaccine primarily stems from challenges in identifying immunogenic viral antigens, insufficient characterization of ASFV pathogenesis, and limited understanding of the virus’s immune evasion mechanisms. Here, we review the pathogenic characteristics (morphological structure, clinical symptoms, and epidemiological characteristics), molecular biological characteristics, and infection mechanism of ASFV, as well as the immune response mechanism, vaccine research, and the latest information on ASFV in other areas. This review will be in favour of understanding the current state of knowledge of ASF and developing effective vaccines to control this disease.

The structural stability of barrier layers is critical for the long-term effectiveness of landfill remediation projects, although leachate pumping and organic contamination can cause structural degradation, reduce remediation performance, and increase the risk of pollutant release. The objectives of this study were to determine the consolidation–rebound mechanisms of sand–bentonite mixtures through standardized tests and to analyze deformation under diesel contamination using multi-scale approaches, including pore-structure characterization, particle-size distribution, cation exchange capacity, and oil-blocking effects. The results revealed that uncontaminated soil (0.0 wt.% diesel) exhibited non-linear compression behavior, with an initial decrease and a subsequent increase with increasing sand content; when the consolidation pressure exceeded 400 kPa, the compression rate decreased markedly. The compression deformation of the contaminated soil increased and was positively correlated with the sand and diesel contents, with accelerated deformation at >4.0 wt.% diesel. The rebound capacity decreased under combined sand–diesel effects. Microstructural analysis indicated that initial compression was controlled by inter-aggregate pores, whereas mid- to late-stage compression was influenced by intra-aggregate pore evolution and particle breakage. Increased diesel content shifted aggregate breakage from single/secondary to tertiary patterns, altering later compression behavior. Coupled hydration reduction and enhanced oil-blocking suppressed rebound significantly, worsening with increasing diesel content. Technical–economic analysis revealed that pure bentonite (0% sand) was optimal under uncontaminated conditions and that a 10% sand mixture was best under contaminated conditions. The sand–bentonite barrier exhibited amplified consolidation–rebound deformation and reduced stability with increasing sand and diesel contents, providing a theoretical basis for long-term landfill remediation assessment.

We investigate the evolution of an external particle jet in a dense particle bed subjected to a radially divergent air-blast. Both random and single-mode perturbations are considered. By analysing the particle dynamics, we show that the Rayleigh–Taylor instability (RTI), the Richtmyer–Meshkov instability (RMI) and large particle inertia contribute to the formation of the external jet. The external particle jet exhibits a spike-like structure at its top and a bubble-like structure near its bottom. As the expanding particle bed lowers the internal gas pressure, particles near the bubble experience strong inward coupling forces and undergo RTI with variable acceleration. Meanwhile, particles in the spike experience weak gas–particle coupling and collision forces due to large particle inertia and low particle volume fraction, respectively. Consequently, the particles in the spike retain a nearly constant velocity, in contrast to the accelerating spikes observed in cylindrical RTI. To investigate the contributions of RMI to the particle jet growth, we track the trough-near particles in the single-mode perturbation case. It is revealed that the trough-near particles accelerate under the perturbation-induced pressure gradient, overtaking the crest-near particles and inducing phase inversion, thereby resulting in an increase in jet length. We establish a linear-growth model for the jet length increment, similar to the planar Richtmyer–Meshkov impulsive model. Combined with the jet-length-increment model, we propose an external-particle-jet-length model that is consistent with both numerical and experimental results for diverse initial gas pocket central pressures and particle bed thicknesses.

Appropriate soil water and nitrogen (N) management strategies are critical for achieving sustainable agricultural development in drylands. Straw mulching has been used to improve crop yield and water use efficiency (WUE), but N management strategies may need to be adjusted from conventional practice. The current study investigated the interactive effects of N application rate (conventional and high N rate), N application frequencies (single, and split N in 2 – 3 applications) and seasonal conditions on wheat population density dynamics, yield, harvest index (HI), grain protein content, water- and N-use efficiency, and residual soil N under straw mulching on the Loess Plateau of China. Nitrogen rate had no effect on yield, HI, WUE and grain protein content, but high N rate resulted in lower grain weight and nitrogen partial factor productivity (PFPN), and higher soil N residue. Splitting N applications significantly improved grain yield (7%), HI (9%), grain protein content (5%), PFPN and N harvest index, along with a reduction in soil N residue, compared to single application. However, there was no difference in above traits between split-N in 2 and 3 applications. Conventional N rate (vs. high N rate) and split N application (vs. single application) both alleviated the negative correlation between grain yield and grain protein content, and split N application increased grain N removal per unit yield compared to single N application. It is concluded that conventional N rate combined with split application in two doses, is suitable for straw mulching in drylands of the Loess Plateau, China.

Ice cliffs and supraglacial ponds are key drivers of mass loss on debris-covered glaciers. However, the relationship between melt ponds and adjacent ice cliffs has not been fully explored. We investigated the seasonal drainage patterns of a melt pond on the debris-covered Zhuxi Glacier in southeast Tibet and estimated the mass loss of its adjacent ice cliff during 2023–24. Using hourly time-lapse photogrammetry, we built a series of high-resolution point clouds to quantify the evolution of the ice cliff-pond system. Our findings indicate that subaerial melting and undercutting were the primary mechanisms of ice cliff mass loss during summer. In winter when the pond water level dropped, ice cliff calving became the dominant mode of ice loss. As the water level rose in spring, calving and subaerial melting occurred simultaneously and ice loss from calving accounted for approximately 19.5% of total ice loss from February to July 2024. Our results reveal the transitional state of this ice cliff-pond system, exhibiting characteristics of both melt hotspots and lake-terminating calving fronts, and highlight the interplay between seasonal drainage-refill pond and differing modes of ice loss on adjacent ice cliff. Future research should focus on additional high-resolution monitoring of similar systems and incorporation of ice cliff-pond dynamics in glacier-scale numerical models.

We demonstrate a high-power, flexibly tunable dual-pulse laser via temporal modulation techniques to overcome conventional systems’ fixed pulse width and temporal interval constraints, enhancing precision micro/nanofabrication and nonlinear photonics applications. By combining dispersion-engineered seed pulse shaping for adjustable pulse widths (5.6 ps and 0.38–0.47 ns) with optical-delay synchronized interval tuning (from –4 to 12.5 ns), the system achieves wide flexibility in pulse configuration. Furthermore, detailed nonlinear dynamics studies reveal the picosecond component exhibits reduced amplifier efficiency versus the nanosecond component, primarily due to peak-power-driven irreversible energy transfer to Raman-shifted wavelengths. This unique combination of features enables remarkable performance: 1092 W average power at 16 MHz with precisely tailored 15.9 ps/0.44 ns pulse widths and 4.2 ns temporal interval. This high-power tunability establishes a transformative material processing paradigm from precision machining to photonics, advancing fundamental nonlinear pulse science and setting new industrial laser standards.

We present the flexible delivery of picosecond laser pulses with up to 20 W average power over a 3-m-long sample of anti-resonant hollow-core fiber (AR-HCF) for laser-micromachining applications. Our experiments highlight the importance of optical-mode purity of the AR-HCF for manufacturing precision. We demonstrate that compared with an AR-HCF sample with a capillary to core (d/D) ratio of approximately 0.5, the AR-HCF with a d/D ratio of approximately 0.68 exhibits better capability of high-order-mode suppression, giving rise to improved micromachining quality. Moreover, the AR-HCF delivery system exhibits better pointing stability and setup flexibility than the free-space beam delivery system. These results pave the way to practical applications of AR-HCF in developing advanced equipment for ultrafast laser micromachining.