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In this study, a collaborative radar selection and transmit resource allocation strategy is proposed for multitarget tracking applications in multiple distributed phased array radar networks with imperfect detection performance. The closed-form expression for the Bayesian Cramér-Rao Lower Bound (BCRLB) with imperfect detection performance is obtained and adopted as the criterion function to characterize the precision of target state estimates. The key concept of the developed strategy is to collaboratively adjust the radar node selection, transmitted power, and effective bandwidth allocation of multiple distributed phased array radar networks to minimize the total transmit power consumption in an imperfect detection environment. This will be achieved under the constraints of the predetermined tracking accuracy requirements of multiple targets and several illumination resource budgets to improve its radio frequency stealth performance. The results revealed that the formulated problem is a mixed-integer programming, nonlinear, and nonconvex optimization model. By incorporating the barrier function approach and cyclic minimization technique, an efficient four-step-based solution methodology is proposed to solve the resulting optimization problem. The numerical simulation examples demonstrate that the proposed strategy can effectively reduce the total power consumption of multiple distributed phased array radar networks by at least 32.3% and improve its radio frequency stealth performance while meeting the given multitarget tracking accuracy requirements compared with other existing algorithms.

The reinjection exploitation of hydrothermal resources is a recognized method of sustainable exploitation. The well space between the production and reinjection well is an essential issue because the thermal breakthrough in production well is the main negative impact during reinjection. The migration of reinjection water in the geothermal reservoir depends on the permeability of the reservoir, constrained by the geothermal reservoir characteristics. In this study, A numerical model using the Petrasim software with Tough2, as the core as well as reservoir data of each typical geothermal field in Jiyang depression, was established. The impact of the reservoir porosity and permeability and the thickness of a single sand layer on the migration of reinjection water and temperature field in the geothermal reservoir were analyzed systematically. The simulation results revealed that the reservoir porosity had a minor impact on the reinjection of the geothermal reservoir, including the reinjection pressure and the spacing of production and reinjection wells. The reservoir permeability affected the reinjection pressure, and then controlled the reinjection performance of the geothermal reservoir, while it had no impact on the spacing of production and reinjection wells. The sand layer superposition combination had a minor impact on the reinjection pressure of the geothermal reservoir. The distance of the horizontal migration of reinjection water in the multilayer stacked thin sand layers was longer, and the range of temperature influence was larger. Thus, it is necessary to expand the well space between production and reinjection well. This study is of significance for the stable operation of geothermal development projects.

Gastrointestinal microorganisms in mammals are part of the bacterial ecosystem and play an important role in gastrointestinal development, function and regulation. Short-chain fatty acids (SCFAs) are metabolites produced by fermentation of beneficial bacteria in gastrointestinal microbiome, mainly including acetate, propionate and butyrate. Currently, most studies focus on the effect of microorganisms on host cell metabolism, but the regulation of short-chain fatty acids on intestinal inflammation and its mechanism is still worthy of attention. More and more studies have shown that SCFAs can provide energy for intestinal epithelial cells, protect the intestinal barrier, regulate intestinal inflammation and other functions. In the treatment of intestinal inflammation, SCFAs can be used as signal molecules to activate G protein-coupled receptors (GPCRs) on the cell surface and inhibit histone deacetylases (HDACs) through substrate transporters in the cell, thus achieving anti-inflammatory goals. In this paper, the composition and source of SCFAs, the synthesis pathway and distribution in the body, the effect on intestinal health, the molecular mechanism of regulation in intestinal inflammation and the effect of dietary fiber on the synthesis of SCFAs are reviewed. The mechanism of short-chain fatty acid regulation of intestinal inflammation is emphasized to provide theoretical basis for further research.

Objective To compare the identification effect of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, rpoB gene sequencing and VITEK 2 Compact on Staphylococci. Methods Three methods were used to identify 59 isolates of Staphylococci from food simultaneously. Results The result consistency of MALDI-TOF MS and rpoB gene sequencing was 100. 00%, while the consistency of MALDI-TOF MS with VITEK 2 Compact was 83. 05%(49/59). Seven isolates were misidentified by VITEK 2 Compact because of out of identification range. The MALDI-TOF MS method could quickly identify 59 strains as 17 species of Staphylococci, and the identification score was related to the species. The identification score of Staphylococcus aureus is the highest(> 2. 300), and the identification score of Staphylococcus squirrel, S. piscifermentans and S. succinus was relatively low(1. 700-2. 000). Conclusion Compared with rpoB gene sequencing and VITEK 2 Compact method, MALDI-TOF MS method is more rapid and accurate. In order to achieve a better identification effect, the existing database still needs to be further optimized.

To investigate the effect of combined treatment with L-ascorbic acid (AA) and ultrasound (US) (AS) on the storage quality of fresh-cut taro, the present study measured changes in the sensory quality and browning-related enzyme activities during storage of Yongding grown fresh-cut Liuyuehong taro soaked in 2% AA solution for 15 minutes, followed by US treatment (53 kHz and 400 W for 10 minutes). Compared with the control group, combined treatment with AS could reduce the water loss rate of fresh-cut taro, maintain higher hardness, delay the increase in browning index, reduce cell membrane permeability, inhibit the accumulation of malondialdehyde (MDA), and suppress surface microbial growth, thereby maintaining higher sensory quality of fresh-cut taro. In addition, AS treatment could also maintain higher activities of catalase (CAT) and superoxide dismutase (SOD), decrease the activities of peroxidase (POD), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL), inhibit the consumption of phenolic substances, slow down the loss of nutrients such as starch, soluble proteins, and soluble solids, suppress the accumulation of soluble quinones, and delay the flavor deterioration of fresh-cut taro during storage. These results indicated that AS treatment could maintain better storage quality of fresh-cut taro.