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A coherently driven Kerr optical cavity is able to sustain dissipative temporal solitons, enabling all-optical data storage buffers and broadband frequency combs. Kerr solitons are balanced through an energy exchange with the pump field. Improving the pump-to-soliton energy conversion is of great importance for practical applications, but remains an outstanding challenge owing to a limited pump–soliton temporal overlap. Here we report the discovery of temporal solitons in mutually coupled cavities instead of a traditional single cavity. A pump recycling strategy is proposed, to greatly improve the power utilization efficiency. Using macroscale optical fibre-ring cavities, which share the same physical model as miniature microresonators, we demonstrate nearly 100% pump recycling and the ability to break the efficiency limit of a single cavity. This study could greatly extend the applications of temporal cavity solitons and provides an attractive platform for exploring the complex nonlinear dynamics in coupled cavity systems.Efficient power transfer from the pump to the soliton can be achieved through field coupling between two optical resonators, allowing soliton frequency comb generation with tens-to-hundreds-of-fold improvement in conversion efficiency compared with a traditional single-resonator comb.

Understanding the emergence of cooperation in spatial public goods game remains a grand challenge across disciplines. In most previous studies, it is assumed that the investments of all the cooperators are identical, and often equal to 1. However, it is worth mentioning that players are diverse and heterogeneous when choosing actions in the rapidly developing modern society and researchers have shown more interest to the heterogeneity of players recently. For modeling the heterogeneous players without loss of generality, it is assumed in this work that the investment of a cooperator is a random variable with uniform distribution, the mean value of which is equal to 1. The results of extensive numerical simulations convincingly indicate that heterogeneous investments can promote cooperation. Specifically, a large value of the variance of the random variable can decrease the two critical values for the result of behavioral evolution effectively. Moreover, the larger the variance is, the better the promotion effect will be. In addition, this article has discussed the impact of heterogeneous investments when the coevolution of both strategy and investment is taken into account. Comparing the promotion effect of coevolution of strategy and investment with that of strategy imitation only, we can conclude that the coevolution of strategy and investment decreases the asymptotic fraction of cooperators by weakening the heterogeneity of investments, which further demonstrates that heterogeneous investments can promote cooperation in spatial public goods game.

Solitons are self-reinforcing localized wave packets that manifest in the major areas of nonlinear science, from optics to biology and Bose–Einstein condensates. Recently, optically driven dissipative solitons have attracted great attention for the implementation of the chip-scale frequency combs that are decisive for communications, spectroscopy, neural computing, and quantum information processing. In the current understanding, the generation of temporal solitons involves the chromatic dispersion as a key enabling physical effect, acting either globally or locally on the cavity dynamics in a decisive way. Here, we report on a novel class of solitons, both theoretically and experimentally, which builds up in spectrally confined optical cavities when dispersion is practically absent, both globally and locally. Precisely, the interplay between the Kerr nonlinearity and spectral filtering results in an infinite hierarchy of eigenfunctions which, combined with optical gain, allow for the generation of stable dispersion-less dissipative solitons in a previously unexplored regime. When the filter order tends to infinity, we find an unexpected link between dissipative and conservative solitons, in the form of Nyquist-pulse-like solitons endowed with an ultra-flat spectrum. In contrast to the conventional dispersion-enabled nonlinear Schrödinger solitons, these dispersion-less Nyquist solitons build on a fully confined spectrum and their energy scaling is not constrained by the pulse duration. Dispersion-less soliton molecules and their deterministic transitioning to single solitons are also evidenced. These findings broaden the fundamental scope of the dissipative soliton paradigm and open new avenues for generating soliton pulses and frequency combs endowed with unprecedented temporal and spectral features. A novel class of solitons, which builds up in spectrally confined optical cavities when dispersion is practically absent, is revealed both theoretically and experimentally, opening new avenues for generating soliton pulses and frequency combs endowed with unprecedented temporal and spectral features.

Strange stars ought to exist in the universe according to the strange quark matter hypothesis, which states that matter made of roughly equal numbers of up, down, and strange quarks could be the true ground state of baryonic matter rather than ordinary atomic nuclei. Theoretical models of strange quark matter, such as the standard MIT bag model, the density-dependent quark mass model, or the quasi-particle model, however, appear to be unable to reproduce some of the properties (masses, radii, and tidal deformabilities) of recently observed compact stars. This is different if alternative gravity theory (e.g., non-Newtonian gravity) or dark matter (e.g., mirror dark matter) are considered, which resolve these issues. The possible existence of strange stars could thus provide a clue to new physics, as discussed in this review.

Ultrawideband beamforming is essential for next-generation radar and communication systems, however, the instantaneous bandwidth of phase-shifter-based phased array antennas (PAAs) is limited by beam squint. Photonic true-time-delay (TTD) beamformers offer a potential solution, yet their practical deployment is hindered by complex delay-line architectures. Here, we report a frequency-comb-steered photonic quasi-TTD beamforming approach that eliminates delay lines by leveraging frequency-diverse arrays and photonic microwave mixing arrays. This enables squint-free beamforming and continuous beam steering for widely used linear frequency modulation (LFM) waveforms, effectively delivering infinite spatial resolution. We present 16-element linear and 4×4 planar PAA prototypes, achieving 6 GHz instantaneous bandwidth across the entire Ku-band. Furthermore, we demonstrate integrated sensing and communication capabilities, including inverse synthetic aperture radar imaging with 2.6 × 3.0 cm resolution and 4.8 Gbps wireless transmission. This work establishes a compact, robust, and scalable architecture for ultrawideband, large-scale photonic PAAs, paving the way for future integrated radar and communication systems. Ultrawideband beamforming is essential for next generation radar and communication. Here, authors demonstrate a photonic beamforming approach using frequency combs that enables beamforming and continuous beam-steering of LFM waveforms, supporting high-performance integrated sensing and communication.

Physical Activity (PA) is essential for enhancing the physical function of pre-frail and frail older adults. However, among this group, PA-levels vary significantly. Identifying the factors contributing to these differences could support tailored PA interventions. This study aims to examine factors associated with physical activity levels among pre-frail and frail older adults in rural China. This is a cross-sectional study. A total of 284 (pre)frail older adults (aged ≥60 years) were included from ten rural healthcare centers in Northeast China. Participants were categorized into low-moderate and high physical activity groups assessed using the Short Form International Physical Activity Questionnaire. Four-dimensional data were collected, including demographics, health behaviors, objective physical performance measures, and self-reported perceived health profiles. Extreme Gradient Boosting (XGBoost), a machine learning algorithm, was employed for binary classification (low-moderate vs. high physical activity). Model performance was assessed using the area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, precision, and F1-score. To enhance interpretability, SHapley Additive exPlanations (SHAP) were utilized to identify key predictive variables. Mean age of participants was 70 years (59% female, 86% farmers). The low-moderate group averaged 1,187 MET/week, while the high physical activity group reached 8,162 MET/week. Physical performance tests showed significantly better scores in the high PA group. The XGBoost model achieved 82.4% accuracy (AUC: 0.769, specificity: 90%, sensitivity: 63%). SHAP analysis revealed that self-reported social support, general health, ambulation, and physical performance measures were the most important factors. The high physical activity group demonstrated better physical function than the low-moderate physical activity group; though, both groups showed poorer physical function compared to the general older population. Self-reported health perceptions and social support significantly correlated with physical activity levels. Addressing these factors through targeted interventions-including community-based social support programs and structured mobility-enhancing exercises-may contribute to improved health outcomes and enhanced quality of life in this population.

Natural flavonoids are renowned for their exceptional antioxidant properties, but their limited water solubility hampers their bioavailability. One approach to enhancing their water solubility and antioxidant activity involves the use of cyclodextrin (CD) inclusion. This study investigated the impact of CD inclusion on the three primary radical scavenging mechanisms associated with flavonoid antioxidant activity, utilizing apigenin as a representative flavonoid and employing density functional theory (DFT) calculations. Initially, the optimized geometries of CD−apigenin inclusion complexes were analyzed, revealing the formation of hydrogen bonds between CD and apigenin. In less polar environments, the inclusion complex strengthened the bond dissociation enthalpies of hydroxyl groups, thereby reducing antioxidant activity. Conversely, in polar environments, the inclusion complex had the opposite effect by lowering proton affinity. These findings align with experimental results demonstrating that CD inclusion complexation enhances flavonoid antioxidant activity in aqueous ethanol solutions.

The free radical trapping capacities of multiple pyranoanthocyanins in wine storage and ageing were theoretically explored by density functional theory (DFT) methods. Intramolecular hydrogen bonds were detected in all pyranoanthocyanins, and the planarity of the compounds worsened with an increasing dielectric constant in the environment. Solvents significantly influenced the reaction enthalpies; thus, the preferred thermodynamic mechanisms of the free radical scavenging reactions were modified in different phases. This study incorporates hydrogen atom transfer (HAT), proton loss (PL), electron transfer (ET) reactions, and demethylation (De) of methoxy group mechanisms. The three pyranoanthocyanins have the capacity to capture n1+1 free radicals, where n1 represents the number of methoxy groups. In the gas phase, they prefer employing the n1-De-HAT mechanism on the guaiacyl moiety of the B ring, resulting in the formation of a stable quinone or a quinone radical to scavenge free radicals. In the benzene phase, pyranoanthocyanins trap free radicals via a PL−n1−De−HAT mechanism. In the water phase, the targeted pyranoanthocyanins may dissociate in the form of carboxylate and tend to utilize the n2−PL−n1−De−ET mechanism, where n2 and n1 represent the number of phenolic groups and methoxy groups, respectively, facilitating multiple H+/e− reactions.

The regional brand-driven construction of agricultural products has taken shape in China. At present, the status quo entails the homogenization of the brand-driven mode of construction, making it a serious phenomenon in China. In addition, the misalignment between the brand-driven mode and resource conditions in some areas not only causes a waste of resources but also leads to a lack of competitiveness and premium capacity for agricultural products within the brand, which cannot increase farmers’ income. This article constructs a theoretical model of the brand-driven mode and uses the fuzzy set qualitative comparative analysis method to identify effective brand-driven modes and explore their applicable environmental conditions. This research can provide theoretical guidance for the local development of regional brands of characteristic agricultural products. The results of the driving mode validity analysis show that the four brand-driven modes, resource-dependent, technology-induced, culture-driven, and industry-based, are the main construction paths for regional brands of agricultural products in China. Among them, the effectiveness of the resource-dependent and technology-induced modes is the highest, reaching 0.90 or more. The results of the applicability analysis show that the resource-dependent mode is suitable for farming areas with well-developed supporting policies and infrastructure and good economic development. In addition, the use of the technology-induced mode requires local farmers to have a high level of education and a high-quality base.

Non-agricultural employment plays a significant role in alleviating regional poverty. Using the micro data of the China Labor-Dynamics Survey (CLDS), this paper empirically analyzes the impact of the accessibility of rural transportation infrastructure on the non-agricultural employment choices of rural laborers by using the entropy method and the ordered Logit model. The results show that there is a significant positive correlation between the accessibility of rural transportation infrastructure and the non-agricultural employment of rural laborers. The study also finds that the laborers participating in non-agricultural employment in villages with good transportation infrastructure will prefer to be employed in nearby locations, and the development of the rural non-agricultural economy is an important reason. Further analysis clearly shows that gender, the family dependency ratio, and rural terrain characteristics affect the choices made by laborers with respect to non-agricultural employment. Based on the research results, focusing on a transportation and industry model and considering the construction of transportation infrastructure as a guide, especially in areas with poor terrain, promoting the development of rural non-agricultural industries can help solve the problem in rural areas and in women’s employment where family members or accompanying personnel are left behind, and can promote the orderly transfer of rural laborers.