The appeal of quadruped robots lies not only in their ability to mimic the diverse and agile locomotion of animals but also in their potential to integrate with human artistic expression to achieve complex multi-skill movements. Continuous multi-skill motion in quadruped robots requires the realization of diverse, continuous, and long-horizon behaviors, involving a broader state space and more complex motion generation and transitions. This presents significant challenges, including sparse rewards, incomplete data, long-horizon motion planning, and the design of fine-grained motion transitions. In this work, we categorize quadruped robot skills into three types: rhythmic motions, expressive motions, and high-dynamic motions and generate reference trajectories for each category using central pattern generators, animation design, and motion capture, respectively. We then design an asymmetric neural network architecture and employ an imitation–reinforcement learning algorithm to train policies for generating these three types of motions. By composing multiple motion skill trajectories, we avoid long-horizon motion planning; by leveraging reinforcement learning, we enable smooth and continuous skill transitions; and by introducing a two-stage reference state initialization curriculum, the robot is able to switch from arbitrary states to the target motion skill. Moreover, during training, the policy imitates only key characteristics of the reference motions rather than strictly tracking fixed trajectories, making it more robust. Finally, we achieve robust motion skill generation and seamless transitions on a quadruped robot equipped with a 6-DoF manipulator, validating the effectiveness and feasibility of the proposed multi-skill generation and transition method.

This work presents an integrated modelling study of fast-proton distributions generated by ion cyclotron range of frequency (ICRF) minority heating in the Experimental Advanced Superconducting Tokamak (EAST). Using a series of high-confinement (H-mode) discharges with increasing ICRF power levels from 0.8 to 2.4 MW, fast protons were produced via minority heating mechanisms and analysed through simulations using the ASCOT code. The results reveal that the fast protons are primarily concentrated near the fundamental cyclotron resonance layer and exhibit strong power-dependent behaviour in both real-space (R–Z) distribution and velocity space, where R is the major radius and Z is the vertical coordinate. As the ICRF power increases, the energetic proton population shows significant spatial broadening and energy enhancement, reaching up to 1 MeV. The fast-ion pitch-angle distribution becomes increasingly anisotropic, with high-energy ions concentrated around $|\textit{v}_{\|}/\textit{v}| \lt 0.5$, where $\nu$ is the magnitude (speed) of the full velocity vector of the particle. Furthermore, the energy density of fast ions aligns well with the ICRF power deposition profile, confirming efficient central-core heating. These findings, which provide insight into fast-ion behaviour and ICRF heating characteristics in EAST plasmas, also support future fast-ion diagnostics and performance control strategies in EAST and similar experimental conditions.

This study investigates how imposed transverse forced vibration modifies vortex-induced vibration of an elastically mounted cylinder, with a focus on uncovering the nonlinear interplay between forced and self-excited oscillations. Through carefully designed experiments spanning wide ranges of frequency and amplitude ratios under low and high mass ratios, three distinct response regimes are identified. In the dual-frequency regime, occurring at extreme frequency ratios, weak coupling allows coexistence of forced and natural frequencies, yielding alternating large/small amplitudes and wake transitions between two vortex pairs per cycle (2P) and two single vortices per cycle (2S) shedding. The frequency-switching regime, near resonance, features amplitude modulation and intermittent dominance of each excitation source, producing mixed-mode wakes. In the resonant regime, frequency and amplitude matching lead to complete synchronisation, sinusoidal motion and intensified, periodic 2P shedding with elongated shear layers. Crucially, comparative analysis reveals that the structural mass ratio fundamentally governs the regime boundaries and transient dynamics, noticeably compressing the transitional frequency-switching zone. Energy transfer and added mass coefficients reveal enhanced dissipation and inertial modifications near resonance. The observed nonlinear interactions challenge assumptions of linear superposition and offer new insight into coupled vibration control. These findings provide a foundation for designing structures that harness or mitigate flow-induced vibrations in marine, energy and fluid–structure systems.

Discrepancies in iodised salt coverage rate (ISCR) between household salt and that used in catering establishments may significantly compromise the accuracy of dietary iodine intake assessments. To evaluate this impact, we analysed data from the 2023 Shanghai Diet and Health Survey, a cross-sectional study involving 2920 adults. Dietary intake was assessed using three 24-h dietary recalls and an FFQ, while condiment intake was collected using the weighed inventory method. Additionally, salt samples from 960 canteens and restaurants were tested to determine the ISCR in dining establishments. Results showed that the ISCR was 85·9 % in dining establishments, markedly higher than the 53·3 % observed in households. Among employed participants in Shanghai, 51·7 %, 56·1 % and 18·7 % reported consuming breakfast, lunch and dinner outside the home at least once during the 3-d study period, respectively. The estimated daily iodine intake was 101 μg/d when dining-out salt was assumed to have the same ISCR as household salt, but it increased to 118 μg/d after accounting for the ISCR discrepancy. In conclusion, the rising prevalence of eating out has reshaped residents’ dietary habits, rendering traditional household-centric survey methods inadequate for iodine intake estimation in Shanghai. Incorporating ISCR differences between household and dining settings is essential for more accurate dietary iodine assessments.

Planar particle image velocimetry (PIV) measurements were conducted to investigate turbulent flows through a square duct roughened by transverse rectangular ribs of four blockage ratios (${\textit{Br}}=0.1$, 0.15, 0.2 and 0.25) at a bulk Reynolds number of ${\textit{Re}}_b = 9400$. In contrast to the classical two-dimensional (2-D) rib-roughened boundary-layer flows, the turbulent flow studied here is intrinsically three-dimensional (3-D) and inhomogeneous, complicated by not only the internal shear layers (ISLs) triggered by the rib crests, but also the intense interaction of the four boundary layers developing over duct sidewalls. It is observed that turbulent motions near the rib crest are mainly dominated by the ejection and sweep events. As the blockage ratio increases, the magnitudes of Reynolds stresses near the rib crest increase significantly attributed to enhanced sweep events and large-scale flapping motions. The results of temporal auto-correlations and spatial two-point auto-correlations show that both temporal and spatial integral scales of turbulence structures are dominated by the streamwise velocity fluctuations, which increase as the rib height increases. Based on proper orthogonal decomposition (POD) analyses, it is interesting to observe that the ISL near the rib crest is dominated by both the low- and high-frequency flapping motions characteristic of the first POD mode.

Individuals at clinical high risk (CHR) for psychosis exhibit both baseline and progressive brain structural abnormalities. However, the extent to which these changes reflect neurobiological trajectories of illness progression versus iatrogenic effects of antipsychotic (AP) treatment remains unresolved. A total of 148 AP-naïve CHRs and 65 healthy controls (HCs) underwent baseline structural magnetic resonance imaging (MRI) scans. One hundred thirty CHRs received second-generation AP treatment and completed 2-month follow-up scans. HCs also completed the follow-up scans. We compared baseline and longitudinal brain volume changes between CHRs and HCs and explored the relationship between AP treatment and brain structural changes in CHR. At baseline, CHRs showed enlarged third and inferior lateral ventricles compared to HCs. Within CHRs, larger ventricular, as well as smaller hippocampus and amygdala volumes, were associated with more severe symptoms and poorer functioning. No cortical volume differences were observed between groups at baseline, nor were cortical volumes related to clinical symptoms. After 2-month AP treatment, CHRs exhibited continued ventricular enlargement, reduced accumbens volume, and widespread cortical volume loss relative to HCs. Notably, cortical volume reductions were dose-dependent, with higher AP dose correlating with more pronounced cortical reductions. Additionally, cortical volume changes were linked to treatment response, with high-dose responders showing more significant HC-referenced changes compared to high-dose non-responders, low-dose responders, and low-dose non-responders. Our findings underscore the complex, region-specific, and clinically relevant neuroanatomical changes in CHR individuals, emphasizing the critical need to account for AP exposure in CHR neuroimaging studies.

The traditional design of laser drivers for inertial confinement fusion (ICF) is highly dependent on coherent laser light fields, which have significant advantages in achieving harmonic conversion and enhancing amplification efficiency. However, they also bring the core challenge of achieving uniform irradiation. This paper investigates the dynamic evolution process of uniform irradiation of multi-mode spatiotemporal light fields and analyzes the influence mechanism of spatiotemporal coherence on irradiation uniformity with different integration times. By balancing the relationship between the spatiotemporal coherence of the light field and uniform irradiation, we explore a possible scheme to alleviate the beam smoothing problem while satisfying the basic requirements of laser amplification and high-efficiency harmonic conversion. Based on this scheme, the overall architecture of the ICF laser driver is constructed.

Cylindrical vector (CV) $\gamma$ rays can introduce spatially structured polarization as a new degree of freedom for fundamental research and practical applications. However, their generation and control remain largely unexplored. Here, we put forward a novel method to generate CV $\gamma$ rays with tunable hybrid polarization via a rotating electron beam interacting with a solid foil. In this process, the beam generates a coherent transition radiation field and subsequently emits $\gamma$ rays through nonlinear Compton scattering. By manipulating the initial azimuthal momentum of the beam, the polarization angle of $\gamma$ rays relative to the transverse momentum can be controlled, yielding tunable hybrid CV polarization states. Three-dimensional spin-resolved particle-in-cell simulations demonstrate continuous tuning of the polarization angle across $\left(-90{}^{\circ},\ 90{}^{\circ}\right)$ with a high polarization degree exceeding 60%. Our work contributes to the development of structured $\gamma$ rays, potentially opening up new avenues in high-energy physics, nuclear science and laboratory astrophysics.

While the joint modeling of item responses and response times (RTs) has received considerable attention, most existing approaches remain limited to dichotomous items and are not applicable to assessments involving polytomous or mixed-format items. To address this limitation, this article proposes a novel joint modeling framework for graded item responses and RTs. Specifically, we develop a conditional RT model given item responses and integrate it with a marginal response model based on Samejima’s graded response model, yielding a conditional joint model for graded item responses and RTs. The model is then embedded within a two-level hierarchical framework to account for the relationship between ability and speed at the population level. A key methodological contribution is the development of a stochastic approximation EM (SAEM) algorithm for estimating the proposed model, which efficiently computes its marginal maximum likelihood estimates. Simulation studies demonstrate the accurate parameter recovery of the SAEM algorithm and indicate that the proposed model outperforms the hierarchical model assuming conditional independence across various testing conditions. Finally, an empirical analysis using data from the 2022 Programme for International Student Assessment illustrates the effectiveness of the graded response–response time model in large-scale assessments.

Direct numerical simulations with two-way coupled Lagrangian tracking are carried out to study the bubble preferential concentration and the flow field modification. Simulations are conducted in an upward vertical turbulent channel driven by a constant pressure gradient, corresponding to a friction Reynolds number $Re_{\tau 0}=180$. Micro-sized bubbles with diameters ranging from 0.72 to 1.43 wall units are considered. Competition between lift force and wall-lift force in the wall-normal direction leads to significant near-wall bubble accumulation and directly results in distinct preferential concentration patterns across the channel. Below (above) the peak concentration height, the wall-lift (lift) force dominates, driving bubbles to accumulate in regions of high-speed sweep (low-speed ejection) events. In the vicinity of the wall, the wall-normal lift force exhibits a strong correlation with the local streamwise flow velocity, further reinforcing the preferential concentration of bubbles in high-speed regions. Additionally, bubbles show a strong preference for the low-enstrophy and high-dissipation nodal topologies. Furthermore, small bubbles primarily accumulate in the vicinity of the wall, reducing the work done on the flow and leading to a decrease in bulk velocity and turbulence statistics. In contrast, the turbulence statistics of large bubbles are nearly identical to those of the unladen flow. The impact of large bubbles on the flow field primarily manifests as an effective increase in the mean pressure gradient. These findings demonstrate that bubbles in the upward vertical channel flow exhibit strong preferential concentration behaviours, whereas their ability to modulate turbulence remains limited.

At the low-coherence Kunwu laser facility with a 0.6% bandwidth, we experimentally studied the laser absorption efficiency of laser–target coupling at intensities of (3–5) × 1014 W cm–2. To characterize side scattering across a wide angular range, we developed a novel radiochromic film-based diagnostic system, which enables continuous spatial mapping over approximately π steradians for the first time. The results indicate a substantial reduction in total loss rate (by more than three times) when compared to a monochromatic laser. We focused on analyzing the influence of laser bandwidth on stimulated Brillouin scattering and stimulated Raman scattering (SRS). Notably, we found that the broadband laser enhances SRS at high intensities, which is contrary to the results obtained at low intensities. These results highlight the role of bandwidth as a quantitative control parameter for improving laser–plasma coupling, which is of particular significance for advancing direct-drive inertial confinement fusion.

Garnet-bearing silicic volcanic rocks are rare in fossil orogens and usually record a transient stage from regional compression to extension. This study reports newly identified 839 ± 3 Ma garnet-bearing dacitic volcanic rocks associated with the Fuchuan ophiolite complex (FOC) in the eastern Jiangnan Orogen (JO), Southeast China. The presence of these unusual rocks provides new constraints on the late Neoproterozoic tectonic evolution of the orogen.

The garnet-bearing dacitic volcanic rocks of the garnets are weakly peraluminous and exhibit trace element and Nd isotopic signatures similar to those of post-orogenic, strongly peraluminous granites in the eastern JO, indicating a similar crustal source. The garnets are almandine-rich (76–79 wt%) and characterized by low CaO (<2.5 wt%), MnO (<2.6 wt%) and TiO2 (<0.1 wt%), consistent with garnets in peraluminous S-type volcanic rocks globally. Integrated petrological, geochemical and zircon Hf isotopic evidence indicates that the primary magma originated from partial melting of a heterogeneous lower-crustal source, comprising both juvenile basaltic and ancient pelitic components. High zircon saturation temperatures (>900°C) further imply the heating of coeval underplating mantle-derived mafic magma, analogous to the mechanism forming ‘hot granites’.

Integrating our findings with regional geology, we propose that the garnet-bearing dacitic volcanic rocks associated with the FOC formed in an ensialic back-arc basin along the southeastern margin of the Yangtze Craton. The occurrence of the garnet-bearing magmatism records the onset of back-arc extension, likely following the ∼880–860 Ma arc–continent collision and subsequent subduction polarity reversal.