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Multi-unmanned aerial vehicle (UAV) system often encounters sudden static or dynamic obstacle threats during flight. How to realize obstacle avoidance is one of the key problems that must be solved for multi-UAV system. Therefore, this paper proposes a distributed model prediction control algorithm with mode switching. Two control modes (the tracking mode and the collision avoidance mode) and their switching strategies are designed based on risk of collision. Among them, the tracking mode takes tracking trajectory as the goal, and the corresponding algorithm can ensure the asymptotic stability of the system, the collision avoidance mode takes collision avoidance as the primary goal, and collision avoidance constraints are introduced by triggering to achieve collision avoidance between the UAV and the obstacles. Compared with the traditional single-mode predictive control algorithm, the proposed method can make the UAVs avoid the pre-unknown large-scale obstacles more effectively, and has the advantages of low conservativeness and short computation time. Finally, the effectiveness of the method is verified using the simulation of six quadrotors.

Soccer video event detection is of great significance to video retrieval.However,there are fewer events in soccer videos,and these events mainly occur in the far-view shot,which makes it difficult to capture key players and key actions,making soccer event detection more difficult.In recent years,methods based on deep learning have made some progress in soccer video event detection,but the learning ability of the high-level semantic of the event is still insufficient and the detection results need to be further improved.Therefore,how to improve the accuracy of soccer video event detection is an urgent problem to be solved.Taking the shooting event of free kick(free-kick shot event) as the research object,an event detection model combining soccer rules and deep learning is proposed.To have a deeper understanding of the inherent characteristics of the free-kick shot event,the event rules are manually summarized and verified on the public soccer dataset,and the corresponding application scenarios are also proposed.For the problem of too few events in soccer videos,rule-based initial localization algorithm is proposed to preprocess the videos.Through the combination and application of multiple rules,the location where the free-kick shot event may occur is initially located from the original video,which is used as the input of the deep learning model for further prediction.The proposed mo-del is compared with other models on the public soccer dataset.Experimental results show that the proposed model achieves the best results,with the accuracy rate of 78% and the recall rate of 81.25%.Compared with other models,the improvement in accuracy is particularly prominent.It can be seen that the free-kick shot event detection model that combines soccer rules and deep learning effectively improves the performance of free-kick shot event detection and provides a basic reference for further research on the detection of other events in soccer videos.

[Objective] The effects of ridge tillage patterns on soil erosion at sloping croplands in the black soil region of Northeastern China were analyzed in order to provide scientific guidance for soil erosion control in this region. [Methods] The simulated rainfall experiments were conducted at the sloping croplands with the 5° and 10° slope gradients. The simulated rainfall intensities were 50 and 100 mm/h. This study took the traditional up-and downslope ridge tillage as the control treatment. The ridge tillage patterns included contour ridge tillage, ridge-furrow intervals tillage, up and down slope ridge + bottom contour ridge tillage, and contour ridge + drainage ditch tillage. [Results] Under the experimental conditions, the contour ridge tillage, ridge-furrow intervals tillage, up and down slope ridge + bottom contour ridge tillage, and contour ridge + drainage ditch tillage effectively regulated runoff and decreased soil erosion, compared with control treatment. However, the regulation effect of different ridge tillage patterns on runoff and erosion decreased with the increase of rainfall intensity and slope gradient. For the 5° sloping cropland, the regulation effect of contour ridge tillage treatment on runoff and erosion was the best. The runoff rates and soil erosion rates were stable below 15.0 mm/h and 0.2 kg/(m2·h). Under the rainfall intensity of the 50 and 100 mm/h, the runoff was reduced 92.3% and 83.9% respectively, and the soil erosion reduced 96.8% and 94.6% respectively, compared with the control treatments. The runoff reduction and soil erosion reduction benefits of ridge-furrow intervals tillage treatment was slightly greater than those of up and down slope ridge + bottom contour ridge tillage treatment at the 5° sloping cropland. For the 10° sloping cropland, the contour ridge tillage treatment showed better soil water storage and soil conservation capacity in the early stage of rainfall events compared with that of the other ridge tillage patterns. However, the ridges were easy to be damaged in the later stage of rainfall events, caused a rapid increase in soil erosion. In contrast, the contour ridge + drainage ditch tillage treatment could store soil and water in the early stage of rainfall events, and better drained away water in the later stage of rainfall events. [Conclusion] As to gentle sloping croplands, the contour ridge tillage and ridge-furrow intervals tillage patterns should be optimized, in the sloping farmland with steep slope, the contour ridge + drainage ditch tillage pattern should be preferred. Therefore, it is suggested to select suitable ridge tillage patterns according to slope gradients and rainfall characteristics.

BackgroundGenome-wide single marker and gene-based meta-analyses of long-term average (LTA) blood pressure (BP) phenotypes may reveal novel findings for BP.Methods and resultsWe conducted genome-wide analysis among 18 422 East Asian participants (stage 1) followed by replication study of ≤46 629 participants of European ancestry (stage 2). Significant single-nucleotide polymorphisms and genes were determined by a P

Background: Captopril challenge test (CCT), seated saline infusion test (SSIT), oral sodium loading test (OSLT) and fludrocortisone suppression test (FST) are widely used diagnostic tests for primary aldosteronism (PA). These tests differ in terms of safety and complexity. Whether the simpler tests (CCT and SSIT) are comparable in diagnostic performance to the more complex ones (FST and OSLT) is unclear. Purpose: To compare the diagnostic accuracy of the four tests. Methods: This is a retrospective study of hypertensive patients who were screened for PA and completed at least one confirmatory test. The patients were divided into two cohorts: one including those who completed one to three tests was used for the estimation of sensitivity and specificity. The other including those who completed four tests was used for the comparison of accuracy. Bayesian method was used to obtain the sensitivity, specificity, and Youden index of each test. Results: The study included 1011 hypertensive patients. Among them, 895 patients completed one to three tests (including 889 CCT, 605 FST, 611 SSIT and 69 OSLT), and 116 patients completed four tests. SSIT had the highest sensitivity of 0.82(95% CI 0.78–0.86) but the lowest specificity of 0.76(0.70–0.80). OSLT had the lowest sensitivity of 0.65(0.56–0.75) but the highest specificity of 0.91(0.82–0.96). The sensitivity and specificity were 0.78 (95% CI, 0.75–0.82), 0.82 (95% CI, 0.78–0.85), for CCT, and 0.77 (95% CI, 0.73–0.81), 0.87 (95% CI, 0.82–0.91) for FST, respectively. The Youden index was not significantly different among the four tests[0.60(0.55–0.65) for CCT; 0.58(0.51–0.64) for SSIT; (0.64(0.57–0.69) for FST; 0.56(0.43–0.67) for OSLT]. Conclusion: The accuracy of simpler tests is comparable to the more complex ones. Considering the safety and simplicity of CCT, it may be a reasonable first choice when confirming the diagnosis of PA. [ABSTRACT FROM AUTHOR]

Purpose: Adrenal venous sampling (AVS) is recommended for subtyping primary aldosteronism (PA). However, in cases of PA, concurrent subclinical Cushing's syndrome (SCS) has the potential to confound AVS results. Pentixafor, a CXC chemokine receptor type 4–specific ligand, has been reported as a promising marker to evaluate functional nature of adrenal adenomas. This study aims to investigate the clinical value of Gallium-68 Pentixafor Positron Emission Tomography–Computed Tomography (68Ga-Pentixafor PET/CT) in the localization diagnosis of patients with PA plus SCS. Methods: Two patients with a confirmed diagnosis of PA plus SCS underwent AVS and 68Ga-Pentixafor PET/CT. Results: AVS results revealed no lateralization for both patients while 68Ga-Pentixafor PET/CT showed a unilateral adrenal nodule with increased uptake of 68Ga-Pentixafor. Unilateral adrenalectomy was performed based on the results of 68Ga-Pentixafor PET/CT. Subsequently, complete biochemical remission of autonomous aldosterone and cortisol secretion were achieved in both cases. Conclusions: 68Ga-Pentixafor PET/CT shows promising potential for the localization of aldosterone and cortisol co-secreting adrenal adenoma in patients with PA plus SCS. [ABSTRACT FROM AUTHOR]

The key purpose of this research was to investigate the mediating role of academics' self-efficacy in teaching and research (termed 'academic self-efficacy') in the relationship between emotions in teaching and teaching styles. Two hundred and thirty-two academics from 13 higher educational institutions in Shanghai, mainland China, responded to three self-report inventories, each assessing academics' emotions in teaching, efficacy in teaching and research, and teaching styles, respectively. Results showed that academics' emotions in teaching statistically predicted teaching styles, both directly and indirectly -- through academic self-efficacy. Findings have enriched the literature on emotions in teaching, that on teaching styles, and that on teacher/academic self-efficacy. Practical implications are proposed in relation to academics and university senior managers.

The fault cavern type reservoir in Block 1 of Shunbei area is located in the ultra-deep layer and is classified as a volatile oil reservoir. The reservoir is characterized by very deep burial with an oil/gas ratio between 250 and 500 m3/tone and a saturation pressure range of 28-36 MPa. As of March 2021, the formation pressure has dropped to 30.5 MPa and the pressure retention rate is 35.8%. In order to effectively develop this reservoir, it was decided to use a water injection development method with a planned transition to natural gas injection in March 2022 to further enhance recovery and maintain formation pressure. Through evaluation and research, the pressure distribution, production capacity change and reservoir dynamic response during the water injection development stage were analyzed with respect to the characteristics of fracture-controlled fracture-cave type reservoir in Shunbei-1 block. On this basis, the necessity, feasibility, and expected effects of conversion to natural gas injection are explored, including improvement of displacement efficiency, reduction of fluid output, and enhancement of formation energy replenishment. In addition, this study also carries out in-depth research and prediction on the optimization of natural gas injection parameters, the selection of injection methods and possible problems, aiming to provide scientific basis and technical support for the efficient and sustainable development of this block. In order to smoothly promote the implementation of natural gas injection development, a special reservoir description technique applicable to fault cavern type reservoirs was adopted. Based on this foundation, an in-depth study was conducted on the mechanism of natural gas displacement, so as to optimize the layout of the well network and the setting of injection and extraction parameters. In addition, a set of evaluation system for natural gas injection effect in fault cavern type reservoirs was constructed. By adopting the natural gas injection development method and combining the corresponding supporting technology development and optimization measures, the reservoir development efficiency and oil (gas) production rate have been effectively improved, and the risk of gas flaring has been reduced at the same time. These research results are of great significance for ensuring the comprehensive development and effective utilization of oil and gas resources, and provide strong technical support for future development work. [ABSTRACT FROM AUTHOR]

In daily patient-history taking and diagnosis practice, doctors ask questions to gather information from patients and narrow down diagnostic hypotheses. Training medical students to be efficient problem solvers through the use of questioning is therefore important. In this study, the effectiveness of problem-based learning (PBL) and lecture-based learning in improving the questioning abilities of medical students (N = 104) was assessed by a modified 20-question task. In this task, the participants were asked to identify target pictures by asking questions, the problem-solving process of which resembles that of the diagnosis scenario. Moreover, this task requires no medical knowledge, and therefore allows knowledge-irrelevant questioning abilities to be assessed independently. The results show that PBL students generally ask more efficient questions and use fewer questions to complete the task. This finding suggests that PBL curricula may help improve the questioning strategies of medical students and help them diagnose more efficiently in future diagnosis practice.

This study examined three aspects of the clustering strategy used by participants: the differences of clustering strategy between intellectually gifted and average children; the relationship between clustering strategy and recall performance in intellectually gifted and average children; and the differences in recall performance on collaborative recall task of intellectually gifted and average children. Thirty-eight intellectually gifted and 44 intellectually average children were recruited, and their collaborative and individual recall performances were tested. The results showed that intellectually gifted children had better clustering strategy than their peers when adjusted ratio of clustering scores were calculated (p < 0.01); clustering strategy positively correlated with recall performance in intellectually average children (p < 0.05), while no such correlation was found in intellectually gifted children (p = 0.95); there was no collaborative inhibition in the gifted group (p = 0.82). These findings partly resolve the conflicts in individual research and expand on the conclusions regarding collaborative memory.