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Structured light refers to the arbitrarily tailoring of optical fields in all their degrees of freedom (DoFs), from spatial to temporal. Although orbital angular momentum (OAM) is perhaps the most topical example, and celebrating 30 years since its connection to the spatial structure of light, control over other DoFs is slowly gaining traction, promising access to higher-dimensional forms of structured light. Nevertheless, harnessing these new DoFs in quantum and classical states remains challenging, with the toolkit still in its infancy. In this perspective, we discuss methods, challenges, and opportunities for the creation, detection, and control of multiple DoFs for higher-dimensional structured light. We present a roadmap for future development trends, from fundamental research to applications, concentrating on the potential for larger-capacity, higher-security information processing and communication, and beyond.It is the first perspective or review that considers the dimensionality that may be reached with structured light, as well as the opportunities and challenges in pursuing this.

Record-breaking rainfall occurred coherently over subtropical West Asia (WA) and East Asia (EA) in April 2024, both are associated with strong barotropic cyclones on their western sides. Based on linear regression analyses and numerical simulations by a linear baroclinic model (LBM), here we show evidences that these two rainfall extremes are tele-connected and are tied to the record-breaking latent heat release over tropical Indian Ocean (TIO). The record-breaking latent heat release over TIO triggers a stationary Rossby wave train propagating northward. This wave train leads to a barotropic anticyclone over Northern Indian Ocean and a barotropic cyclone over WA, which largely explains the anomalous circulation responsible for extreme WA rainfall. Furthermore, the intense latent heat release associated with the extreme rainfall over WA triggers another stationary Rossby wave train along the Asian subtropical jet (ASJ). This wave train anchors a downstream barotropic cyclone anomaly on the eastern periphery of Tibetan Plateau with southerly flow from South China Sea to Eastern China, in favor of excessive rainfall over the EA region. Notably, observed record-breaking Asian rainfall extremes are concentrated in April 2024, possibly because the strong heating anomaly over TIO is absent in March while the substantially northward shifted ASJ in May cannot anchor a cyclone anomaly over WA in response to heating over TIO. This work highlights the importance of both basic state and tropical heating anomaly in shaping subtropical Asian climate extremes during the decaying phase of El Niño.

Southerly wind in the lower troposphere is an essential feature of East Asian summer monsoon (EASM) circulation, which is reported to be enhanced under global warming scenarios and interglacial epochs. Based on an analysis of an ensemble of CMIP6 models, this study shows that the magnitude of intensification of the EASM circulation is much smaller under global warming scenarios than during interglacial epochs. Distinct changes in the western North Pacific subtropical high (WNPSH) are responsible for the different responses of the EASM circulation. The WNPSH is substantially enhanced during interglacial epochs, which acts to strengthen the southerly wind associated with the EASM on the western flank of the WNPSH. However, the change in the WNPSH is insignificant and cannot strengthen the EASM under global warming scenarios, and the weakly enhanced EASM circulation may be a direct response to intensified heating over the Tibetan Plateau. The land–ocean thermal contrast explains the different responses of the WNPSH. During interglacial epochs, the summertime surface warming over the subtropical North Pacific is much weaker than over Eurasia due to the large thermal inertia of the ocean to increased insolation, and the WNPSH is intensified as a response to the suppressed latent heating over the subtropical North Pacific. The fast response of the WNPSH to abrupt quadrupling of CO₂ without sufficient ocean warming is an analog to the interglacial epochs, but it is offset by the effect of slow oceanic warming, resulting in an insignificant change of the WNPSH under global warming scenarios.

Using the outputs of 33 coupled models that participated in phase 5 of the Coupled Model Intercomparison Project (CMIP5), the changes of the western North Pacific subtropical high (WNPSH) in the 2050–99 period under representative concentration pathway 4.5 and 8.5 (RCP4.5 and RCP8.5) scenarios relative to the 1950–99 period are analyzed. Under both scenarios, the projected changes in the WNPSH intensity are approximately zero in the multimodel ensemble mean (MME), and large intermodel spread is seen. About half of the models project an enhanced WNPSH and about half of the models project a weakened WNPSH under both scenarios. As revealed by both diagnostic studies and numerical simulations, the projected change in the WNPSH intensity is dominated by the change in the zonal sea surface temperature (SST) gradient between the tropical Indian Ocean (TIO) and the tropical western Pacific (TWP). A stronger (weaker) warming in the TIO is in favor of an enhanced (weakened) WNPSH. and a weaker (stronger) warming over the TWP is also in favor of an enhanced (weakened) WNPSH. The projected change of the WNPSH modulates the climate change over eastern China. Under both RCP4.5 and RCP8.5 scenarios, all of the models with a significantly increased (decreased) WNPSH intensity are associated with a significant increase in the precipitation over the northern (southern) part of eastern China and an enhanced (weakened) southerly wind.

Coupled climate system models consistently show that the low-level southerly wind associated with the East Asian summer monsoon (EASM) is enhanced under anthropogenic greenhouse gas forcing, and the enhanced EASM was attributed to the enhanced land–sea thermal contrast by previous studies. Based on a comparison of the global warming scenarios with the present-day climate in an ensemble of 30 coupled models from phase 5 of the Coupled Model Intercomparison Project (CMIP5), we show evidence that changes in land–sea thermal contrast cannot explain the enhanced EASM circulation in terms of the seasonality. Indeed, the enhanced low-level southerly wind over East Asia is associated with a large-scale anomalous cyclone around the Tibetan Plateau (TP), and numerical simulation by the Linear Baroclinic Model suggests that the enhanced latent heating over the TP associated with enhanced precipitation is responsible for this low-level cyclone anomaly and the enhanced EASM circulation projected by the coupled models. Moisture budget analysis shows that enhanced hydrological recycling and enhanced vertical moisture advection due to increased specific humidity have the largest contribution to the increased precipitation over the TP, and more than half of the intermodel uncertainty in the projected change of EASM circulation is associated with the uncertainty in the changes of precipitation over the TP. Therefore, the TP plays an essential role in enhancing the EASM circulation under global warming through enhanced latent heating over the TP.

Classification of electroencephalogram (EEG) is a key approach to measure the rhythmic oscillations of neural activity, which is one of the core technologies of brain-computer interface systems (BCIs). However, extraction of the features from non-linear and non-stationary EEG signals is still a challenging task in current algorithms. With the development of artificial intelligence, various advanced algorithms have been proposed for signal classification in recent years. Among them, deep neural networks (DNNs) have become the most attractive type of method due to their end-to-end structure and powerful ability of automatic feature extraction. However, it is difficult to collect large-scale datasets in practical applications of BCIs, which may lead to overfitting or weak generalizability of the classifier. To address these issues, a promising technique has been proposed to improve the performance of the decoding model based on data augmentation (DA). In this article, we investigate recent studies and development of various DA strategies for EEG classification based on DNNs. The review consists of three parts: what kind of paradigms of EEG-based on BCIs are used, what types of DA methods are adopted to improve the DNN models, and what kind of accuracy can be obtained. Our survey summarizes the current practices and performance outcomes that aim to promote or guide the deployment of DA to EEG classification in future research and development.

Many polarisation techniques have been harnessed for decades in biological and clinical research, each based upon measurement of the vectorial properties of light or the vectorial transformations imposed on light by objects. Various advanced vector measurement/sensing techniques, physical interpretation methods, and approaches to analyse biomedically relevant information have been developed and harnessed. In this review, we focus mainly on summarising methodologies and applications related to tissue polarimetry, with an emphasis on the adoption of the Stokes–Mueller formalism. Several recent breakthroughs, development trends, and potential multimodal uses in conjunction with other techniques are also presented. The primary goal of the review is to give the reader a general overview in the use of vectorial information that can be obtained by polarisation optics for applications in biomedical and clinical research.The review focuses on methodologies and biomedical applications of polarisation optics. It also presents prospects on development trends, the potential multi-modal uses in conjunction with other techniques.

Loquat fruit is one of the most perishable fruits in China, and has a very limited shelf life because of mechanical injury and microbial decay. Due to an increasing concern about human health and environmental security, antagonistic microorganisms have been a potential alternative for fungicides to control postharvest diseases. In this work, the antifungal effect of volatile organic compounds (VOCs) produced by Bacillus methylotrophicus BCN2 and Bacillus thuringiensis BCN10 against five postharvest pathogens isolated from loquat fruit, Fusarium oxysporum, Botryosphaeria sp., Trichoderma atroviride, Colletotrichum gloeosporioides, and Penicillium expansum were evaluated by in vitro and in vivo experiments. As a result, the VOCs released by BCN2 and BCN10 were able to suppress the mycelial growth of all targeted pathogens according to inhibition ratio in the double petri-dish assay as well as disease incidence and disease diameter on loquat fruits. The main volatile compounds were identified by solid-phase microextraction (SPME)-gas chromatography. These VOCs produced by the two strains played complementary roles in controlling these five molds and enabled loquat fruits to keep fresh for ten days, significantly. This research will provide a theoretic foundation and technical support for exploring the functional components of VOCs applicable in loquat fruit preservation.

Summer monsoon rainfall supplies over 55% of annual precipitation to global monsoon regions. As shown by more than 70% of models, including 30 models from CMIP5 and 30 models from CMIP6 under high-emission scenarios, North American (NAM) monsoon rainfall decreases in a warmer climate, in sharp contrast to the robust increase in Asian–African monsoon rainfall. A hierarchy of model experiments is analyzed to understand the mechanism for the reduced NAM monsoon rainfall in this study. Modeling evidence shows that the reduction of NAM monsoon rainfall is related to both direct radiative forcing of increased CO₂ concentration and SST warming, manifested as fast and slow responses to abrupt CO₂ quadrupling in coupled GCMs. A cyclone anomaly forms over the Eurasian–African continental area due to enhanced land–sea thermal contrast under increased CO₂ concentration, and this leads to a subsidence anomaly on its western flank, suppressing the NAM monsoon rainfall. The SST warming acts to further reduce the rainfall over the NAM monsoon region, and the El Niño–like SST warming pattern with enhanced SST warming over the equatorial Pacific plays a key role in suppressing NAM rainfall, whereas relative cooling over the subtropical North Atlantic has no contribution. A positive feedback between monsoon precipitation and atmospheric circulation helps to amplify the responses of monsoon rainfall.