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The aggregation of locusts from solitary to gregarious phases is crucial for the formation of devastating locust plagues. Locust management requires research on the prevention of aggregation or alternative and greener solutions to replace insecticide use, and insect-derived microRNAs (miRNAs) show the potential for application in pest control. Here, we performed a genome-wide screen of the differential expression of miRNAs between solitary and gregarious locusts and showed that miR-8-5p controls the γ-aminobutyric acid (GABA)/glutamate functional balance by directly targeting glutamate decarboxylase (Gad). Blocking glutamate–GABA neurotransmission by miR-8-5p overexpression or Gad RNAi in solitary locusts decreased GABA production, resulting in locust aggregation behavior. Conversely, activating this pathway by miR-8-5p knockdown in gregarious locusts induced GABA production to eliminate aggregation behavior. Further results demonstrated that ionotropic glutamate/GABA receptors tuned glutamate/GABA to trigger/hamper the aggregation behavior of locusts. Finally, we successfully established a transgenic rice line expressing the miR-8-5p inhibitor by short tandem target mimic (STTM). When locusts fed on transgenic rice plants, Gad transcript levels in the brain increased greatly, and aggregation behavior was lost. This study provided insights into different regulatory pathways in the phase change of locusts and a potential control approach through behavioral regulation in insect pests.

Insect flight is a complex physiological process that involves sensory and neuroendocrinal control, efficient energy metabolism, rhythmic muscle contraction, and coordinated wing movement. As a classical study model for insect flight, locusts have attracted much attention from physiologists, behaviorists, and neuroendocrinologists over the past decades. In earlier research, scientists made extensive efforts to explore the hormone regulation of metabolism related to locust flight; however, this work was hindered by the absence of molecular and genetic tools. Recently, the rapid development of molecular and genetic tools as well as multi-omics has greatly advanced our understanding of the metabolic, molecular, and neuroendocrinal basis of long-term flight in locusts. Novel neural and molecular factors modulating locust flight and their regulatory mechanisms have been explored. Moreover, the molecular mechanisms underlying phase-dependent differences in locust flight have also been revealed. Here, we provide a systematic review of locust flight physiology, with emphasis on recent advances in the neuroendocrinal, genetic, and molecular basis. Future research directions and potential challenges are also addressed.

With the rapid development of Internet of things technology, context-aware systems (CASs) are being gradually improved and widely applied to many fields such as digital home, smart health and so on. However, context information from sensor-rich CASs usually has inconsistency, which leads to wrong decisions made by systems, and even lowers user experience. Therefore, a new overall quality of context (OQoC) indicator is defined, which is the effective fusion of the parameters of reliability, up-to-dateness and modified correctness. Its accurate measurement is of great importance in inconsistency elimination. Moreover, we put forward a new context inconsistency elimination algorithm based on OQoC and Dempster–Shafer theory. The performance of the proposed algorithm is verified in personal identity verification scenario. Experimental results from multiple dimensions fully show the superiority of the proposed algorithm in solving context inconsistency problem, and quality of context information using the proposed algorithm has been greatly improved.

The hypoxia inducible factor (Hif) pathway is functionally conserved across metazoans in modulating cellular adaptations to hypoxia. However, the functions of this pathway under aerobic physiological conditions are rarely investigated. Here, we show that Hif-1α2, a locust Hif-1α isoform, does not induce canonical hypoxic responses but functions as a specific regulator of locust flight, which is a completely aerobic physiological process. Two Hif-1α splice variants were identified in locusts, a ubiquitously expressed Hif-1α1 and a muscle-predominantly expressed Hif-1α2. Hif-1α1 that induces typical hypoxic responses upon hypoxia exposure, remains inactive during flight. By contrast, the expression of Hif-1α2, which lacks C-terminal transactivation domain, is less sensitive to oxygen-tension but induced extensively by flying. Hif-1α2 sustains flight endurance by promoting glucose oxidation while simultaneously maintaining redox homeostasis by upregulating the production of a reactive oxygen species (ROS) quencher, DJ-1. Overall, this study reveals a novel Hif-mediated mechanism underlying prolonged aerobic physiological activity.

Significance Migratory locusts display striking phenotypical plasticity. Gregarious locusts at high density can migrate long distances and cause huge economic losses of crops. By contrast, solitary locusts at low density have limited ability in long-distance flight. However, the mechanisms underlying such flight capacity variation are poorly understood. Here, we found that the flight muscle of solitary locusts has a higher catabolic capacity that is associated with greater reactive oxygen species (ROS) generation during high-velocity flights. By contrast, a relatively lower catabolic capacity in gregarious locusts is associated with lower ROS generation during long-distance flights. This finding uncovers the metabolic mechanism of locust flight trait alteration in response to density changes and enhances our understanding of the biological processes enabling locust migration., Flight ability is essential for the enormous diversity and evolutionary success of insects. The migratory locusts exhibit flight capacity plasticity in gregarious and solitary individuals closely linked with different density experiences. However, the differential mechanisms underlying flight traits of locusts are largely unexplored. Here, we investigated the variation of flight capacity by using behavioral, physiological, and multiomics approaches. Behavioral assays showed that solitary locusts possess high initial flight speeds and short-term flight, whereas gregarious locusts can fly for a longer distance at a relatively lower speed. Metabolome–transcriptome analysis revealed that solitary locusts have more active flight muscle energy metabolism than gregarious locusts, whereas gregarious locusts show less evidence of reactive oxygen species production during flight. The repression of metabolic activity by RNA interference markedly reduced the initial flight speed of solitary locusts. Elevating the oxidative stress by paraquat injection remarkably inhibited the long-distance flight of gregarious locusts. In respective crowding and isolation treatments, energy metabolic profiles and flight traits of solitary and gregarious locusts were reversed, indicating that the differentiation of flight capacity depended on density and can be reshaped rapidly. The density-dependent flight traits of locusts were attributed to the plasticity of energy metabolism and degree of oxidative stress production but not energy storage. The findings provided insights into the mechanism underlying the trade-off between velocity and sustainability in animal locomotion and movement.

Multi-view video coding (MVC) utilizes hierarchical B picture prediction structure and adopts many coding techniques to remove spatiotemporal and inter-view redundancies at the cost of high computational complexity. In this paper, a novel perceptual distortion threshold model (PDTM) is proposed to reveal the relationship between the mode selection of inter-frame prediction and coding distortion threshold. Based on the proposed PDTM, a new fast inter-frame prediction algorithm in MVC is developed aimed at minimizing computational complexity for dependent view coding. Then the fast MVC algorithm is incorporated into the multi-view High Efficiency Video Coding (MV-HEVC) software to improve MVC coding efficiency. In practical coding, the mode selection for inter-frame prediction of dependent views may be early terminated based on the thresholds derived from the PDTM, thereby reducing the coding time complexity. Experimental results demonstrate that the proposed algorithm can reduce the computational complexity of the dependent views by 52.9% compared with the HTM14.1 algorithm under the coding structure of hierarchical B pictures. Moreover, the bitrate is increased by 0.9% under the same subjective quality and only increased by 1.0% under the same objective quality peak signal-to-noise ratio (PSNR). Compared with the state-of-the-art fast algorithm, the proposed algorithm can save more coding time, while the bitrate under the same PSNR increases slightly.

Long noncoding RNAs (lncRNAs) regulate various biological processes from gene expression to animal behavior. Although protein-coding genes, microRNAs, and neuropeptides play important roles in the regulation of phenotypic plasticity in migratory locust, empirical studies on the function of lncRNAs in the process remain limited. Here, we applied high-throughput RNA-seq to characterize the expression patterns of lncRNAs and mRNAs in the time course of the locust phase change. LncRNAs displayed more rapid response at the early stages of the time-course treatments than mRNA expression. Functional annotations demonstrated that early changed lncRNAs employed different pathways in isolation and crowding processes to cope up with the changes in population density. Finally, two overlapping hub lncRNA loci in the crowding and isolation networks were screened to be functionally verified. Experimental validation indicated that LNC1010057 could act as a potential regulator to modulate the locust phase change. This work offers new insights into the mechanism underlying the locust phase change and expands the scope of lncRNA functions in animal behavior.

In most gesture recognition research fields, feature extraction is based on single finger. In this paper, we propose an improved finger feature extraction algorithm based on double fingers, and it is easier to judge the projected distance and angle of five fingertips and can be better applied to gesture recognition with multi-fingers' information. Furthermore, K-nearest neighbor (KNN) classifier based on entropy-weight allocation (WE-KNN) is proposed to improve the accuracy of gesture recognition. Compared with traditional algorithms, the proposed finger feature extraction algorithm combined with WE-KNN can enhance the accuracy of gesture recognition on Leap Motion dataset. What's more, we apply the proposed algorithms to the gesture interaction system of virtual gym scenario, which can increase the interactive fun and improve the interactive experience.

Dempster-Shafer (D-S) evidence theory is an uncertain reasoning method which has great application value in data fusion and other areas. However, it can usually lead to counter-intuitive results when fusing the highly conflictive evidences. In this paper, an improved D-S evidence theory based on gray relational analysis is proposed. The proposed method considers the basic probability assignment (BPA) of every evidence as a data sequence, and assigns a weight to each sequence to modify the original evidence model, and then fuses the evidences by D-S combination rule. The new evidence model is more reliable so that the fusion result is more accurate. A numerical example and an experiment on Iris dataset are given to illustrate effectiveness by comparing with other D-S evidence based methods.

Context-aware systems are becoming increasingly popular and are widely used in many areas such as smart healthcare, digital home, and so on. The existing context-aware system frameworks mainly focus on the improvement of organization mode of the system modules, but they normally lack a quantitative and comprehensive quality index to describe and evaluate the overall system performance. In this paper, QoX is innovatively defined as a comprehensive quality index that combines quality of device (QoD), quality of context (QoC), quality of service (QoS) and quality of experience (QoE). Meanwhile, QoX is integrated into the context-aware system and a context-aware system framework based on QoX is proposed, which provides an effective model for rational use of context and optimal system design. Besides, by studying the relation among QoX related indicators, systems can actively adjust various preset thresholds and rules according to the changes of users' needs and environmental conditions, which would make systems more reliable and adaptive and provide users with personalized and intelligent services.

In the dynamic and open environment, context-aware systems (CASs) obtain context information from dynamic, distributed and heterogeneous sources, but this context information usually has the inconsistency which would lead to inappropriate services. In this paper, a multi-source homogeneous continuous context inconsistency elimination algorithm based on the improved basic probability assignment (BPA) is proposed, aiming to solve the context inconsistency from multi-source homogenous sensors. In terms of the multi-source homogeneous context inconsistency elimination, we adopt sensor precision, membership degree and current data distance to modify the BPA on the basis of fully consideration of the frequency and amplitude of context. In the aspect of frequency, the precision is used to determine the probability. For the amplitude of context, we use the concept of membership degree from fuzzy set theory in the horizontal dimension and distances between the data at the current moment in the longitudinal dimension to assign the probability. The experiment results show that the continuous context inconsistency elimination algorithm proposed in this paper can significantly improve the accuracy of the context inconsistency elimination.

Asymmetric stereoscopic video coding is becoming increasingly popular, as it can reduce the bandwidth required for stereoscopic 3D delivery without degrading the visual quality. Based on the perceptual theory of binocular suppression, the left and right views of stereoscopic video are coded with different levels of quality. However, existing asymmetric perceptual coding approaches on stereoscopic video mainly focus on the threshold of whole image distortion. It is not so reasonable to use a single unified rather than adaptable perception threshold for a random natural stereoscopic image as the texture complexity typically varies in different blocks of image. In this paper, we generated an asymmetrically distorted stereoscopic image set with different texture densities and conducted a large number of subjective perceptual experiments. A strong correlation between the asymmetrical visibility threshold and texture complexity is revealed from the subjective experiments, and a texture-based asymmetrical visibility threshold model (TAVT) is established. Then, the model is extended to the hierarchical B picture (HBP) coding architecture and an asymmetric stereoscopic video coding method is proposed based on the TAVT model. Experimental results show that the proposed method can effectively reduce the unnecessary perceptual redundancy without visual quality degradation. Especially, it is more efficient for high bitrate configuration.

Dopamine receptor 1 (Dop1) mediates locust attraction behaviors, however, the mechanism by which Dop1 modulates this process remains unknown to date. Here, we identify differentially expressed small RNAs associated with locust olfactory attraction after activating and inhibiting Dop1. Small RNA transcriptome analysis and qPCR validation reveal that Dop1 activation and inhibition downregulates and upregulates microRNA-9a (miR-9a) expression, respectively. miR-9a knockdown in solitarious locusts increases their attraction to gregarious volatiles, whereas miR-9a overexpression in gregarious locusts reduces olfactory attraction. Moreover, miR-9a directly targets adenylyl cyclase 2 (ac2), causing its downregulation at the mRNA and protein levels. ac2 responds to Dop1 and mediates locust olfactory attraction. Mechanistically, Dop1 inhibits miR-9a expression through inducing the dissociation of La protein from pre-miR-9a and resulting in miR-9a maturation inhibition. Our results reveal a Dop1–miR-9a–AC2 circuit that modulates locust olfactory attraction underlying aggregation. This study suggests that miRNAs act as key messengers in the GPCR signaling., Migratory locusts shift between aggregating together during gregarious phases and living individually during solitary phases. Here, the authors find that the D1-like dopamine receptor regulates the olfactory attraction underlying this behavioral switch via microRNA-9a and adenylyl cyclase.

Visual quality assessment of stereo image plays an important role in three dimensional visual communication. Considering the processing of binocular perception in viewing stereo image, we present a reduced-reference (RR) stereo image quality assessment (SIQA) model based on binocular perceptual characteristics. Firstly, stereo images are divided into binocular fusion portion and binocular rivalry portion with internal generative mechanism. Then, cyclopean view is generated according to the binocular fusion portion and binocular rivalry portion with binocular perception, and the Gaussian scale mixture RR features from cyclopean view and the binocular rivalry portion for SIQA. Finally, the quality indicators of cyclopean view and binocular rivalry portion are computed to obtain the final SIQA score. The proposed model is tested on the LIVE 3D IQA database. Experimental results show that compared with the state-of-the-art methods, the proposed model has high correlation with subjective perception and can evaluate human stereo visual properties effectively.

Existing perceptual researches on stereoscopic images mainly focus on the threshold of whole image distortion, rather than the effect of texture feature on the so-called threshold of just-noticeable distortion. Obviously, it is unreasonable to use a single unified perception threshold for natural stereoscopic images as the texture complexity typically varies in different blocks of natural images. To solve this problem, we generated an asymmetrically distorted stereoscopic image database with different texture densities and conducted a large number of subjective experiments. A strong correlation between the asymmetrical visibility threshold and texture complexity was revealed from the subjective experiments. Finally, a nonlinear fitting model was designed to uncover this relationship, which can be applied to asymmetrical coding to control the perceived quality of stereoscopic images.