Construction of oxime ester derivatives of osthole from Cnidium monnieri , and evaluation of their agricultural activities and control efficiency

2020 ◽  
Vol 76 (11) ◽  
pp. 3560-3567
Author(s):  
Zili Ren ◽  
Min Lv ◽  
Tianze Li ◽  
Meng Hao ◽  
Shaochen Li ◽  
...  
Author(s):  
Andreas Müller ◽  
Shivesh Kumar

AbstractDerivatives of equations of motion (EOM) describing the dynamics of rigid body systems are becoming increasingly relevant for the robotics community and find many applications in design and control of robotic systems. Controlling robots, and multibody systems comprising elastic components in particular, not only requires smooth trajectories but also the time derivatives of the control forces/torques, hence of the EOM. This paper presents the time derivatives of the EOM in closed form up to second-order as an alternative formulation to the existing recursive algorithms for this purpose, which provides a direct insight into the structure of the derivatives. The Lie group formulation for rigid body systems is used giving rise to very compact and easily parameterized equations.


2019 ◽  
Vol 123 (1267) ◽  
pp. 1437-1453
Author(s):  
X. L. Ai ◽  
Y. C. Shen ◽  
L. L. Wang

ABSTRACTThis paper considers the integrated guidance and control (IGC) problem for impact angle constrained interception against manoeuvring targets with actuator saturation constraint. Based on the backstepping technique, an adaptive IGC law is presented to address this problem, where a fixed-time differentiator is proposed to estimate the derivatives of virtual control inputs to avoid the inherent problem of “explosion of complexity” suffered by the typical backstepping. Furthermore, an auxiliary first-order filter is introduced into the IGC law to cope with the actuator saturation constraint. The stability of the closed-loop system is strictly proved. Finally, the superiority of the proposed IGC law is verified by comparison simulations.


PMLA ◽  
1904 ◽  
Vol 19 (3) ◽  
pp. 335-448 ◽  
Author(s):  
Gordon Hall Gerould

In any study which involves the consideration of a network of stories, it is chiefly necessary to regard the skeleton upon which the tales in question are built up. Although it is impossible to decide upon the relationship of the various members of a cycle without some consideration of individual incidents and even turns of thought or phrase, it is constantly necessary to check and control the information thus gained by the larger matters of motive and purpose. Individual incidents and all the flesh and blood of a narrative are so easily changed that the skeleton appears stable in comparison. With due regard to the kaleidoscopic changes which are familiar to every student of this field of comparative literature, it furnishes the clue by which the labyrinth of plots must be threaded, if at all.


2021 ◽  
pp. 123-126

Reliable and up-to-date data on every soil segment of the land areas cultivated for the contemporary land utilization is of vital significance. Currently, the efficient planning and control over the agricultural activities is hardly possible without any reliable and updated information on the yield and agricultural soil types, whereas implementation of drones in the field of land management and in agriculture, on the whole, is one of the most perspective directions, since unlike the artificial sattelites, they provide more precise and guided images for the given location. The aim of the research is to produce the digital field model and NDVI map for the crops by applying Parrot Disco-Pro AG drone kit.


Author(s):  
Ankita Wal ◽  
Pranay Wal ◽  
Ruchi Tiwari

Objective: The neuropharmacological activities of ethanolic extract derivatives of lupeol are being screened on rats. Prepared derivatives are evaluated for their locomotor, anxiolytic and stereotype activities. The present investigation was designed to evaluate the antipsychotic effect of semisynthetic derivatives of lupeol using rat models of elevated maze model and apomorphine-induced stereotype behavior.Methods: Lupeol was extracted from Crataeva nurvala bark using ethano. After chemical modification, we made different derivatives using aldol condensation. Different derivatives were obtained from a series of reaction previously published LAH-3, LAP-3, LAPEA-3, LAMP-3, LATS-3, and LAS-3. Neuropharmacological effects, including anxiolytic, central nervous inhibitory, and stereotype antipsychotic effects were evaluated in the different derivatives of lupeol at a dose of 250 mg/kg using standard methods.Results: The absolute derivatives of LAH3 and LAPEA3 showed a significant reduction in the activity score in actophotometer test. Reduction in the locomotor activity indicates central nervous system (CNS) depressant property of the drug. LAMP3 and LAS3 show a significant anxiolytic effect. From the result of elevated plus maze, it was evident that derivatives of lupeol treated animals exhibit an increased number of entries into open arm when compared to normal control, which shows the anxiolytic activity of the lupeol derivatives. Sniffing, rearing and licking activities for lupeol derivatives LAH3 and LAPEA3 were found to be 35%, 33%, and 40% and 40.33%, 38%, and 33.33% respectively when it compared with standard and control groups. This model is suggestive of the absence of negative symptoms alleviating property of all the treatment groups.Conclusions: The lupeol and its semisynthetic derivatives possess anxiolytic, CNS inhibitory, and antipsychotic effects to varying degree.


Author(s):  
Eric Joël Fofiri Nzossié ◽  
Christophe Bring

Over the past ten years, the Cameroonian cotton front, in the Sudano-Sahelian region, has experienced dynamics in soybean production, resulting in significant changes in agro-systems. From a simple hut culture not referenced in regional agricultural statistics, since 2010, soybean ranks 2nd in legumes cultivated after peanuts, followed by cowpea and voandzou, yet culturally and economically more adopted by the populations. The rapid development of cultivated areas from 6,705 ha in 2008 to 15,020 ha in 2018 is indicative of the enthusiasm shown by farmers for this speculation which, despite the almost lack of supervision on the part of public authorities, now structures a real value chain with challenges for improving farmers’ incomes, in a space where more than 80% of working people live from agricultural activities. The objective of this research is therefore to analyse the sustainability challenges of a productive and market dynamics built around speculation subject to strong demands of international competitiveness. The results show that the viability of this dynamics remains precarious through a set of constraints inherent in the proven inability of farmers to empower themselves to optimise production and control marketing, as well as the poor technical supervision of cultivation.


Agronomy ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 187 ◽  
Author(s):  
Zhaoxia Lou ◽  
Fang Xin ◽  
Xiaoqiang Han ◽  
Yubin Lan ◽  
Tianzhu Duan ◽  
...  

Unmanned aerial vehicles (UAVs), as emerging plant protection machinery, have the advantages of high operational efficiency, high speed, and low drift. The current study aimed to elucidate the characteristics of droplet distribution and drift, control efficiency on cotton aphids and spider mites, and attachment and absorption of cotton leaves during UAV spraying. Kromekote card and filter paper are used as samplers to collect droplets, and the droplet density, coverage rate, deposition, and drift percentage are statistically analyzed. The pooled results showed that the droplet uniformity, the droplet coverage rate, the deposition, and the drifting ability are higher when the UAV flight height was 2 m. The control effects by UAV spraying on cotton aphids and spider mites were 63.7% and 61.3%, respectively. These values are slightly inferior to those obtained through boom spraying. Cotton leaf attachment and absorption of spirodiclofen after UAV spraying were slightly lower than those after boom spraying, therefore, the control efficiency of cotton pests is slightly different. According to the different flight height operations by the UAV sprayer, the drift capability of the droplets at 2 m flight height was large, and the droplet uniformity and deposition were satisfactory. The research results could provide the theoretical basis and technical support for UAV operation.


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