Quantum properties of fermionic fields in multi-event horizon spacetime

We investigate the properties of quantum entanglement and mutual information in the multi-event horizon Schwarzschild-de Sitter (SdS) spacetime for massless Dirac fields. We obtain the expression for the evolutions of the quantum state near the black hole event horizon (BEH) and cosmological event horizon (CEH) in the SdS spacetime. Under the Nariai limit, the physically accessible entanglement and mutual information are maximized, and the physically inaccessible correlations are zero. With the increase in temperature of either horizon, the physically accessible correlations experience degradation. Notably, the initial state remains entangled and can be utilized in entanglement-based quantum information processing tasks, which differs form the scalar field case. Furthermore, the degradation of physically accessible correlations is more pronounced for small-mass black holes. In contrast, the physically inaccessible correlations separated by the CEH monotonically increase with the radiation temperature, and such correlations are not decisively influenced by the effect of particle creation at the BEH. Moreover, a similar phenomenon is observed for the inaccessible correlations separated by the BEH. This result differs from the single event spacetime, in which the physically inaccessible entanglement is a monotonic function of the Hawking temperature.Comment: 14 pages, 7 figure

Gravity enhanced quantum spatial target detection

Quantum illumination can utilize entangled light to detect the low-reflectivity target that is hidden in a bright thermal background. We apply this technique to the detection of an object under the curved spacetime of the Earth, and are especially interested in how the curvature of spacetime influences the spatial quantum illumination. We find that in the near-Earth curved spacetime, the spatial quantum illumination with entangled state transmitter outperforms the one with coherent state transmitter. Furthermore, whether the quantum illumination system or the coherent state system is employed, the detection error-probability and the transmitted modes in the curved spacetime case are always lower than those in the flat spacetime case. That is to say, the Earth's gravity makes the spatial target detection more efficient. This is because the effects of gravity on the illumination signal beam can cancel each other out, while the thermal noise in the return signal is reduced because of the gravitational effect.Comment: 16 pages, 5 figure

A Study of Neural Collapse Phenomenon: Grassmannian Frame, Symmetry, Generalization

In this paper, we extends original Neural Collapse Phenomenon by proving Generalized Neural Collapse hypothesis. We obtain Grassmannian Frame structure from the optimization and generalization of classification. This structure maximally separates features of every two classes on a sphere and does not require a larger feature dimension than the number of classes. Out of curiosity about the symmetry of Grassmannian Frame, we conduct experiments to explore if models with different Grassmannian Frames have different performance. As a result, we discover the Symmetric Generalization phenomenon. We provide a theorem to explain Symmetric Generalization of permutation. However, the question of why different directions of features can lead to such different generalization is still open for future investigation.Comment: 25 pages, 2 figure

Research Progress on the Quality Formation Mechanism of Dry-Aged Meat

Dry-aging is the aerobic aging process where meat carcasses or primal cuts are hanged and aged for a period of time (28 to 55 days, or even longer) under specific environmental conditions of temperature (0–4 ℃), relative humidity (61%–85%), and air flow (0.5–2.0 m/s). Dry-aging in a breathable bag, dry-aging combined with ultraviolet irradiation treatment, and stepwise dry/wet-aging have been successively developed. Due to dehydration during dry-aging, the surface of meat shrinks to produce a hard ‘crust’, resulting in significant mass loss and trim loss. However, compared with wet-aging, dry-aging can significantly enhance meat flavor characteristics, imparting a strong ‘dry-aged flavor’ and unique roasted beef-like, roasted nutty and buttery aromas to aged meat. Dry-aging can be used effectively to improve the eating quality and economic value of low-marbled beef. In this paper, the key parameters of dry-aging are reviewed, the potential mechanism by which dry-aging improves meat quality, especially flavor, is discussed. Future prospects for the application and development of dry-aging are discussed as well. This review will provide theoretical support for the development of the meat industry and for exploring the market for high-quality meat

Effects of the Largest Lake of the Tibetan Plateau on the Regional Climate

Qinghai Lake is the largest lake in China. However, its influence on the local climate remains poorly understood. By using an atmosphere-lake coupled model, we investigated the impact of the lake on the local climate. After the adjustment of four key parameters, the model reasonably reproduced the lake-air interaction. Superimposed by the orographic effects on lake-land breeze circulation, the presence of the lake enhanced precipitation over the southern part of the lake and its adjacent land, while slightly reduced precipitation along the northern shore of the lake. The lake effect on local precipitation revealed a distinct seasonal and diurnal variability, reducing precipitation in May (-6.6%) and June (-4.5%) and increasing it from July (5.7%) to November (125.6%). During the open water season, the lake's daytime cooling effect weakened and the nighttime warming effect strengthened, affecting spatial distribution and intensity of lake-induced precipitation. In early summer, precipitation slightly decreased over the north part of the lake due to the lake's daytime cooling. In turn, lake-induced nighttime warming increased precipitation over the southern section of the lake and its adjacent land. With the start of the autumn cooling in September, heat and moisture fluxes from the lake resulted in precipitation increase in both daytime and nighttime over the entire lake. In October, the background atmospheric circulation coupled with the strong lake effects lead to a small amount but high proportion of lake-induced precipitation spreading evenly over the lake.Peer reviewe

Knowledge-Driven Semantic Segmentation for Waterway Scene Perception

Semantic segmentation as one of the most popular scene perception techniques has been studied for autonomous vehicles. However, deep learning-based solutions rely on the volume and quality of data and knowledge from specific scene might not be incorporated. A novel knowledge-driven semantic segmentation method is proposed for waterway scene perception. Based on the knowledge that water is irregular and dynamically changing, a Life Time of Feature (LToF) detector is designed to distinguish water region from surrounding scene. Using a Bayesian framework, the detector as the likelihood function is combined with U-Net based semantic segmentation to achieve an optimized solution. Finally, two public datasets and typical semantic segmentation networks, FlowNet, DeepLab and DVSNet are selected to evaluate the proposed method. Also, the sensitivity of these methods and ours to dataset is discussed

Research progress on the application of shoulder orthosis in rehabilitation of abnormal gait post-stroke hemiplegia

Post-stroke hemiplegia usually has an adverse impact on motor ability and stability. Patients often develop shoulder subluxation and abnormal gait due to muscle weakness， bilateral limb muscle tension imbalance， sensory abnormalities and poor joint and posture control， etc. Shoulder orthosis is often used to prevent or treat shoulder subluxation in the early stage of stroke hemiplegia， but it is still controversial. To explore the role of shoulder orthosis beyond the prevention and treatment of shoulder subluxation， and to provide theoretical basis for the selection and wearing of shoulder orthosis，the mechanism underlying the role of shoulder orthosis in improving abnormal gait post-stroke hemiplegia was elaborated， and the effects of different types of shoulder orthosis on the rehabilitation of abnormal gait post-stroke were compared

Severe loneliness and isolation in nursing students during Covid-19 lockdown: a phenomenological study

In 2022, COVID-19 continued to spread across the globe, and to stop the spread of the virus and protect people’s health, universities across China continued to remain in a lockdown state. Loneliness is an important topic among college students, and the coronavirus pandemic has exacerbated loneliness. This prolonged school lockdown was unprecedented and it caused severe social isolation and emotional loneliness for students. Few people know how nursing students experience loneliness and find a way through their experience. This qualitative phenomenological study was conducted to reveal the lived experiences of nursing students who indicated COVID-19 lockdown-related loneliness in a previous quantitative survey. We performed 20 semi-structured interviews with nursing students aged 19–23 yrs during their lockdown (April 2022 to June 2022). Our research applied Colaizzi’s seven-step data analysis processes to reveal shared patterns in terms of how nursing students experienced lockdown and found the following four themes: emotional challenges associated with loneliness; causes of loneliness; positive and negative motivation to learn; and accepting solitude and reconstructing real life