Efficient and Accurate Co-Visible Region Localization with Matching Key-Points Crop (MKPC): A Two-Stage Pipeline for Enhancing Image Matching Performance

Image matching is a classic and fundamental task in computer vision. In this paper, under the hypothesis that the areas outside the co-visible regions carry little information, we propose a matching key-points crop (MKPC) algorithm. The MKPC locates, proposes and crops the critical regions, which are the co-visible areas with great efficiency and accuracy. Furthermore, building upon MKPC, we propose a general two-stage pipeline for image matching, which is compatible to any image matching models or combinations. We experimented with plugging SuperPoint + SuperGlue into the two-stage pipeline, whose results show that our method enhances the performance for outdoor pose estimations. What's more, in a fair comparative condition, our method outperforms the SOTA on Image Matching Challenge 2022 Benchmark, which represents the hardest outdoor benchmark of image matching currently.Comment: 9 pages with 6 figures. Many experiments have not yet been conducted, the theoretical sections are rather concise, and the references are not adequately comprehensive. This version of the paper is being released to make this work public, and code will also be published soon. We will continue to conduct additional experiments and periodically update the pape

Arylpyrrole and fipronil analogues that inhibit the motility and/or development of Haemonchus contortus in vitro

Due to widespread drug resistance in parasitic nematodes, there is a need to develop new anthelmintics. Given the cost and time involved in developing a new drug, the repurposing of known chemicals can be a promising, alternative approach. In this context, we tested a library (n = 600) of natural product-inspired pesticide analogues against exsheathed third stage-larvae (xL3s) of Haemonchus contortus (barber's pole worm) using a whole-organism, phenotypic screening technique that measures the inhibition of motility and development in treated larvae. In the primary screen, we identified 32 active analogues derived from chemical scaffolds of arylpyrrole or fipronil. The seven most promising compounds, selected based on their anthelmintic activity and/or limited cytotoxicity, are arylpyrroles that reduced the motility of fourth-stage larvae (L4s) with significant potency (IC50 values ranged from 0.04 ± 0.01 μM to 4.25 ± 0.82 μM, and selectivity indices ranged from 10.6 to 412.5). Since the parent structures of the active compounds are uncouplers of oxidative phosphorylation, we tested the effect of selected analogues on oxygen consumption in xL3s using the Seahorse XF24 flux analyser. Larvae treated with the test compounds showed a significant increase in oxygen consumption compared with the untreated control, demonstrating their uncoupling activity. Overall, the results of the present study have identified natural product-derived molecules that are worth considering for chemical optimisation as anthelmintic drug leads. Keywords: Arylpyrrole, Fipronil, Haemonchus contortus, Anthelmintic, Drug discover

Dynamical analysis of an integrated pest management predator–prey model with weak Allee effect

In this paper, a pest management predator–prey model with weak Allee effect on predator and state feedback impulsive control on prey is introduced and analysed, where the yield of predator released and intensity of pesticide sprayed are assumed to be linearly dependent on the selected pest control level. For the proposed model, the existence and stability of the order-1 periodic orbit of the control system are discussed. Meanwhile, with the aim of minimizing the input cost in practice, an optimization model is constructed to determine the optimal quantity of the predator released and the intensity of pesticide sprayed. The theoretical results and numerical simulations indicated that the number of pests can be limited to below an economic threshold and displays periodic variation under the proposed control strategy. In addition, it indicated in numerical simulations that an order-2 periodic orbit exists for some certain parameters

Performance of ecological concrete-based ecological systems (ECBESs) for nitrogen removing from synthetic farmland drainage water

Efficiency and mechanism of nitrogen removals by ecological concrete-based ecological systems (ECBESs) were investigated in this study. Results show that ECBES performed well on denitrification. Ecological concrete as matrix of the ecological was positive for nitrogen removing according to that the experimental ECBESs achieved a greater TN removal compared to the control system. This result was possibly attributable to a higher biomass and increased bacteria diversity in ECBESs, since ecological concrete could be a carrier of microorganism. Vegetation could further improve TN removals. Acorus calamus L. - ECBES, Ipomoea aquatica Forsk - ECBESs, Oenanthe javanica (Bl.) DC. - ECBES and Zizania aquatica - ECBES achieved an average TN removal of 67.87%, 81.93%, 76.18%, 66.22%, respectively, in a test cycle. Nitrogen transformation in the ECBESs indicated the occurrence of ammonification, nitrification and denitrification. Moreover, bacteria related to nitrogen transformation was identified from the bio-film immobilized on the ecological concrete

Cascade Electrophilic Iodocyclization: Efficient Preparation of 4‑Iodomethyl Substituted Tetrahydro-β-carbolines and Formal Synthesis of Oxopropaline G

4-Iodomethyl substituted tetrahydro-β-carbolines, the core structure of numerous natural products and bioactive molecules, are readily prepared via I₂-promoted cascade electrophilic cyclization. The reactivity differences of olefins and alkynes ensure that the reaction proceeds smoothly. This methodology was successfully applied to the formal synthesis of oxopropaline G

Pressure controlling method for managed pressure drilling with supercritical carbon dioxide as the circulation fluid

Heat transfer along the wellbore was analyzed, and then a closed mathematical model, which fully couples the hydrostatic pressure, temperature, physical properties of CO2 and friction, was established to keep bottom-hole pressure constant during drilling process. Based on the pressure profile in wellbore achieved for a certain surface back pressure, a pressure controlling method for managed pressure drilling with supercritical carbon dioxide was presented. The influences of mass flow rate, well depth and inlet temperature on the annulus pressure profile and surface back pressure were investigated. The results show that, the pressure profile is almost in linear correlation with well depth in the annulus, which provides convenience for well control. The needed back pressure (applied by surface choke) decreases with increasing mass flow rate and decreasing well depth. The impact of inlet temperature on the annulus pressure profile, surface back pressure and flow friction is negligible. It also shows that the density of CO2 increases significantly and abruptly at a critical pressure. It is suggested that the storage pressure of CO2 in surface tank be larger than the critical pressure for a certain temperature. Key words: supercritical carbon dioxide drilling, managed pressure drilling, wellbore heat transfer, annulus pressure, surface back pressur

Selection of automatic vertical drilling system for the fourth section in Shunbei 11 well, Tarim basin, China

Based on the introduction of the working principles of various automatic vertical drilling systems (VDS), the latter are divided into rotary push type and sliding push type. Then the technical advantages and applicable scope of various types of drilling tools are analysed. Combined with the latest domestic application progress and typical case analysis of the vertical drilling system, the future development direction of the vertical drilling technology is predicted. The results show that, the existing vertical drilling technology can better meet the technical needs of rapid drilling in the middle-deep sections with high steep angles. While the stability of wireless information transmission and wear resistance of the push pad still need further improvement. The new type of vertical drilling system that is miniaturized (suitable for small boreholes) and resistant to high temperature and high pressure is in urgent need to fill the gaps in the market segment. Domestic independent vertical drilling systems have made great progress, some even surpass foreign products in key indicators such as temperature resistance, in addition to achieving the technical goal of anti-inclination successfully. Finally, based on the engineering geological conditions of Shunbei 11 well, feasible vertical drilling tools were recommended and achieved engineering goal finally. The research results can provide support for the drilling company to optimize the vertical drilling system based on engineering-geological conditions