Summer Westerly Jet in Northern Hemisphere during the Mid-Holocene: A Multi-Model Study

The upper-level jet stream, a narrow band of maximum wind speed in the mid-latitude westerlies, exerts a considerable influence on the global climate by modulating the transport and distribution of momentum, heat and moisture. In this study by using four high-resolution models in the Paleoclimate Modelling Intercomparison Project phase 3, the changes of position and intensity of the northern hemisphere westerly jet at 200 hPa in summer during the mid-Holocene (MH), as well as the related mechanisms, are investigated. The four models show similar performance on the westerly jet. At the hemispheric scale, the simulated westerly jet has a poleward shift during the MH compared to the preindustrial period. The warming in arctic and cooling in the tropics during the MH are caused by the orbital changes of the earth and the precipitation changes, and it could lead to the weakened meridional temperature gradient and pressure gradient, which might account for the poleward shift of the westerly jet from the thermodynamic perspective. From the dynamic perspective, two maximum centers of eddy kinetic energy are simulated over the North Pacific and North Atlantic with the north deviation, which could cause the northward movement of the westerly jet. The weakening of the jet stream is associated with the change of the Hadley cell and the meridional temperature gradient. The largest weakening is over the Pacific Ocean where both the dynamic and the thermodynamic processes have weakening effects. The smallest weakening is over the Atlantic Ocean, and it is induced by the offset effects of dynamic processes and thermodynamic processes. The weakening over the Eurasia is mainly caused by the dynamic processes

Simultaneous nitrification and denitrification based on internal circulation baffled reactor

Nitrogen removal experiments were carried out by using an internal circulation baffled bioreactor (ICBBR). Nitrate, nitrite and ammonia were used as N source for nitrogen removal experiments. The ICBBR has high nitrogen removal capacity. The removal rates of total nitrogen, nitrate, and nitrite are almost the same. When nitrate and nitrite were used as N sources their kinetic orders were 0.88. When ammonia was used as N source simultaneous nitrification and denitrification (SND) was realized in ICBBR and ammonia removal fitted also 0.88 order kinetics, but total nitrogen removal fitted third-order kinetics. Nitrate and nitrite removal rates were faster than ammonia removal rate under the same C/N ratio, and total nitrogen removal rate increased with increasing C/N ratio

Photocatalysis: A Possible Vital Contributor to the Evolution of the Prebiotic Atmosphere and the Warming of the Early Earth

The evolution of the early atmosphere was driven by changes in its chemical composition, which involved the formation of some critical gases. In this study, we demonstrate that nitrous oxide (N2O) can be produced from Miller’s early atmosphere (a mixture of CH4, NH3, H2, and H2O) by way of photocatalysis. Both NH3 and H2O were indispensable for the production of N2O by photocatalysis. Different conditions related to seawater and reaction temperature are also explored. N2O has a strong greenhouse gas effect, which is more able to warm the Earth than other gases and offers a reasonable explanation for the faint young Sun paradox on the early Earth. Moreover, the decomposition of N2O into N2 and O2 can be boosted by soft irradiation, providing a possible and important origin of atmospheric O2 and N2. The occurrence of O2 propelled the evolution of the atmosphere from being fundamentally reducing to oxidizing. This work describes a possible vital contribution of photocatalysis to the evolution of the early atmosphere

Detecting and Identifying Industrial Gases by a Method Based on Olfactory Machine at Different Concentrations

Gas sensors have been widely reported for industrial gas detection and monitoring. However, the rapid detection and identification of industrial gases are still a challenge. In this work, we measure four typical industrial gases including CO2, CH4, NH3, and volatile organic compounds (VOCs) based on electronic nose (EN) at different concentrations. To solve the problem of effective classification and identification of different industrial gases, we propose an algorithm based on the selective local linear embedding (SLLE) to reduce the dimensionality and extract the features of high-dimensional data. Combining the Euclidean distance (ED) formula with the proposed algorithm, we can achieve better classification and identification of four kinds of gases. We compared the classification and recognition results of classical principal component analysis (PCA), linear discriminate analysis (LDA), and PCA + LDA algorithms with the proposed SLLE algorithm after selecting the original data and performing feature extraction. The experimental results show that the recognition accuracy rate of the SLLE reaches 91.36%, which is better than the other three algorithms. In addition, the SLLE algorithm provides more efficient and accurate responses to high-dimensional industrial gas data. It can be used in real-time industrial gas detection and monitoring combined with gas sensor networks

Efficacy and safety of microwave ablation for benign breast lesions: a systematic review and meta-analysis

AIM: We performed a systematic review and meta-analysis to evaluate the efficacy and safety of microwave ablation (MWA) for benign breast lesions. MATERIAL AND METHODS: PubMed, Embase, Web of Science, Cochrane Library databases, China National Knowledge Infrastructure, and Wanfang Data Knowledge Service Platform databases were searched. RESULTS: A total of 10 studies were included, giving a sample size of 1241 patients and 2729 benign breast lesions. The first complete ablation success rate was 96%. The volume reduction ratio (VRR) after 3/6/12 months was 47.4%, 62.1%, and 85.8%, respectively. After 12 months, the lesion disappearance rate was 53.6%, and the efficiency rate was 99%. The rate of excellent cosmesis was 88% and the rate of good cosmesis was 10%. The complication rate was 2%. CONCLUSIONS: MWA is safe and effective for treating benign breast lesions. It can be a promising minimally invasive choice for benign breast lesions

Three Yersinia enterocolitica AmpD Homologs Participate in the Multi-Step Regulation of Chromosomal Cephalosporinase, AmpC

In many gram negative bacilli, AmpD plays a key role in both cell well recycling pathway and β-lactamase regulation, inactivation of the ampD causes the accumulation of 1,6-anhydromuropeptides and results in the ampC overproduction. In Yersinia enterocolitica, the regulation of ampC expression may also relys on the ampR-ampC system, the role of AmpD in this species is still unkonwn. In this study, three AmpD homologues (AmpD1, AmpD2 and AmpD3) have been identified in complete sequence of strain Yersinia enterocolitica subsp. palearctica 105.5R(r). To understand the role of three AmpD homologues, several mutant strains were constructed and analyzed where a rare ampC regulation mechanism was observed: low-effective ampD2 and ampD3 cooperate with the high-effective ampD1 in the three levels regulation of ampC expression. Enterobacteriaceae was used to be supposed to regulate ampC expression by two steps, three steps regulation was only observed in Pseudomonas aeruginosa. In this study, we first reported that Enterobacteriaceae Y.enterocolitica can also possess a three steps stepwise regulation mechanism, regulating the ampC expression precisely