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The classification of sleep stages is an important process. However, this process is time-consuming, subjective, and error-prone. Many automated classification methods use electroencephalogram (EEG) signals for classification. These methods do not classify well enough and perform poorly in the N1 due to unbalanced data. In this paper, we propose a sleep stage classification method using EEG spectrogram. We have designed a deep learning model called EEGSNet based on multi-layer convolutional neural networks (CNNs) to extract time and frequency features from the EEG spectrogram, and two-layer bi-directional long short-term memory networks (Bi-LSTMs) to learn the transition rules between features from adjacent epochs and to perform the classification of sleep stages. In addition, to improve the generalization ability of the model, we have used Gaussian error linear units (GELUs) as the activation function of CNN. The proposed method was evaluated by four public databases, the Sleep-EDFX-8, Sleep-EDFX-20, Sleep-EDFX-78, and SHHS. The accuracy of the method is 94.17%, 86.82%, 83.02% and 85.12%, respectively, for the four datasets, the MF1 is 87.78%, 81.57%, 77.26% and 78.54%, respectively, and the Kappa is 0.91, 0.82, 0.77 and 0.79, respectively. In addition, our proposed method achieved better classification results on N1, with an F1-score of 70.16%, 52.41%, 50.03% and 47.26% for the four datasets.

Osmoregulation is important for plant growth, development and response to environmental changes. SNF1-related protein kinase 2s (SnRK2s) are quickly activated by osmotic stress and are central components in osmotic stress and abscisic acid (ABA) signaling pathways; however, the upstream components required for SnRK2 activation and early osmotic stress signaling are still unknown. Here, we report a critical role for B2, B3 and B4 subfamilies of Raf-like kinases (RAFs) in early osmotic stress as well as ABA signaling in Arabidopsis thaliana . B2, B3 and B4 RAFs are quickly activated by osmotic stress and are required for phosphorylation and activation of SnRK2s. Analyses of high-order mutants of RAFs reveal critical roles of the RAFs in osmotic stress tolerance and ABA responses as well as in growth and development. Our findings uncover a kinase cascade mediating osmoregulation in higher plants. Rapid activation of SnRK2 kinases is central to plant responses to osmotic stress and abscisic acid. Here the authors show that a group of Raf-like kinases are very quickly activated by osmotic stress, and then phosphorylate and activate SnRK2s.

Effective global environmental governance is the only viable way to solve the human environmental crisis. For a long time, China has been an active promoter and contributor to the global environmental governance system. In recent years, China has enhanced the penalty intensity of environmental crimes, the environmental pollution crimes in particular, and received good results in order to better realize the construction of ecological civilization and better fulfill the emission reduction targets of international environmental treaties. The deterioration of China’s environmental crisis in the past and the lack of deterrent effect of China’s environmental laws are closely related to the ineffective punishment of environmental crimes. In order to better promote environmental protection careers, China’s environmental crimes still need to be continuously optimized in terms of adding charges, legislative models and restorative justice.

There are two options for environmental tort remedy in China: resorting to environmental administration or environmental justice, with an ongoing debate over which of the two should lead. Firstly, it compares the structure of China’s environmental tort remedy system and the two types of power: administrative power and judicial power, concluding that administrative power is dominant. Then, it argues for the indispensability of judicial power, attempts to find a clear boundary between the two sides, and justifies their mutual division of labor and collaboration. Through sufficient demonstration, it clarifies why the dominant position of environmental administrative power must be guaranteed. Then, it summarizes the experience of other countries and the practice of environmental protection in China; and provides three innovative paths of the future environmental rights remedy system. These three aspects are setting up a review procedure for administrative priority judgment before filing an environmental lawsuit, establishing the independent position of experts in environmental litigation, advocating a risk communication mechanism other than litigation, and providing a richer institutional guarantee for the relief of environmental rights.

Research on phononic crystals with negative refractive indices constitutes the most crucial approach to achieving ultra-high-resolution acoustic lenses. This study presents a glide-reflection (GR) symmetrical phononic crystal (PC), and the mismatch of the Wannier center between two PCs leads to the emergence of edge states (ESs). By constructing a single-domain wall, the negative refraction is achieved due to the excitation of ESs with negative dispersion. Further, by stacking multiple GR symmetric PC interfaces, the coupled edge states (CESs) are found, which originate from the coupling between the adjacent interfaces. Thus, stronger negative sound refraction effects with negative transverse displacement can be achieved, because the incident sound wave can be coupled into the CESs with negative dispersion. Simulation results are conducted using the finite element method to verify our idea, and our research provides a novel methodology for the design of acoustic negative refraction.

High-Q resonances in metasurfaces, stemming from symmetry-protected bound states in the continuum (BICs), have proven to be effective for achieving high-performance optical devices. However, the properties associated with symmetry-protected BICs are inherently limited, as even a slight variation in the asymmetry parameter leads to a noticeable shift in the resonance location. Herein, we introduce the concept of relative shift–induced quasi-BICs (QBICs) within dimerized silicon (Si) meta-lattices (DSMs), which can be excited when a nonzero relative shift occurs, a result of in-plane inversion symmetry breaking and Brillouin zone folding within the structure. These QBICs have resonance locations that remain insensitive to variations in asymmetrical parameters. Additionally, their Q-factors can be flexibly tuned, benefiting from the inverse square dependence on asymmetrical parameters. In experiment, six DSMs with different relative shifts are fabricated and the asymmetry parameter-insensitive resonant modes under two orthogonal polarization states are experimentally observed in the optical communication waveband. Our results offer unique opportunities for constructing high-Q resonators with enhanced performances, which can be applied in various optical fields.

We propose a surface plasmon resonance (SPR) sensor based on the concave photonic crystal fiber (PCF) coated with molybdenum disulfide (MoS2) and Au layers, which can detect the refractive index (RI) of the analyte. The finite element method (FEM) was used to verify our design, and the loss spectra of the fundamental mode are calculated. Compared with the SPR sensor with only a Au layer, the wavelength sensitivity can be improved by from 3700 to 4400 nm/RIU. Our proposed sensor works in near-infrared band and has a wide RI range from 1.19 to 1.40. The influences of the geometrical parameters of PCF and the thicknesses of Au and MoS2 layers on the loss spectra are discussed in detail, and the maximum wavelength sensitivity of 5100 nm/RIU can be achieved. Meanwhile, a high resolution of 1.96 × 10−5 RIU and the largest FOM of 29.143 can be obtained. It is believed that our findings show the sensor’s excellent potential in medical testing, unknown biological detection, environmental monitoring and organic chemical detection.

In modern society, law is one of the most important means of risk prevention and control. Under the challenge of ecological and environmental risks, China’s legal governance experience provides important historical experience and theoretical samples for other countries. Faced with problems, such as the difficulty of eliminating risks, risk decisions themselves bring risks, and the huge social cost of risk response, the social system theory can provide novel and new ideas for the cognition and response of environmental risks. Combining the experience of judicial practice with social theory, especially Niklas Luhmann’s doctrine of the risk/danger dichotomy, a clearer functional orientation can be given to judicial powers based on risk communication and risk attribution. By reviewing the ecological judicial practices in China, Germany, and other countries, the role of the legal system in stabilizing the normative expectations of the whole of society can be summarized, which will provide a reference for the risk response and legal governance of the global ecological environment.

This paper reports on a numerical study of the six-band metamaterial absorber composed of two alternating stack of metallic-dielectric layers on top of a continuous metallic plane. Six obvious resonance peaks with high absorption performance (average larger than 99.37%) are realized. The first, third, fifth, and the second, fourth, sixth resonance absorption bands are attributed to the multiple-order responses (i.e., the 1-, 3- and 5-order responses) of the bottom- and top-layer of the structure, respectively, and thus the absorption mechanism of six-band absorber is due to the combination of two sets of the multiple-order resonances of these two layers. Besides, the size changes of the metallic layers have the ability to tune the frequencies of the six-band absorber. Employing the results, we also present a six-band polarization tunable absorber through varying the sizes of the structure in two orthogonal polarization directions. Moreover, nine-band terahertz absorber can be achieved by using a three-layer stacked structure. Simulation results indicate that the absorber possesses nine distinct resonance bands, and average absorptivities of them are larger than 94.03%. The six-band or nine-band absorbers obtained here have potential applications in many optoelectronic and engineering technology areas.

Capabilities for recording neural activity in behaving mammals have greatly expanded our understanding of brain function. Some of the most sophisticated approaches use light delivered by an implanted fiber-optic cable to optically excite genetically encoded calcium indicators and to record the resulting changes in fluorescence. Physical constraints induced by the cables and the bulk, size, and weight of the associated fixtures complicate studies on natural behaviors, including social interactions and movements in environments that include obstacles, housings, and other complex features. Here, we introduce a wireless, injectable fluorescence photometer that integrates a miniaturized light source and a photodetector on a flexible, needle-shaped polymer support, suitable for injection into the deep brain at sites of interest. The ultrathin geometry and compliant mechanics of these probes allow minimally invasive implantation and stable chronic operation. In vivo studies in freely moving animals demonstrate that this technology allows high-fidelity recording of calcium fluorescence in the deep brain, with measurement characteristics that match or exceed those associated with fiber photometry systems. The resulting capabilities in optical recordings of neuronal dynamics in untethered, freely moving animals have potential for widespread applications in neuroscience research.