Influence of environmental parameters on the distribution of subfossil chironomids in surface sediments of Bosten lake (Xinjiang, China)

The distribution of larval subfossil chironomids in surface sediment samples obtained from Bosten lake was analysed, and ordination methods were used to identify the influences of physical and chemical parameters on the abundance and diversity of chironomids. A total of 18 chironomid taxa was identified across the 32 samples, 15 of which showed minimum abundance of >1% and were present in more than one site. Chironomus plumosus-type, Microchironomus and Tanytarsus glabrescens-type were the most abundant of the 18 chironomid taxa identified. The distribution of the main chironomid species within Bosten Lake exhibited spatial heterogeneity. T. glabrescens-type was found to dominate Huangshuiwan, in the northwest part of Bosten lake, which had higher salinity and organic content. Microchironomus was mainly distributed in the Kaidu river mouth, in the southwest part of Bosten lake, whereas C. plumosus-type was more abundant in the deep centre, suggesting the importance of water chemistry, water dynamics and water depth on chironomid distribution. The relationship of chironomid distribution with environmental parameters was assessed using redundancy analysis, and the results revealed that water depth, Secchi depth and salinity were the predominant factors influencing chironomid distribution; these factors could explain the chironomid variances of 18.3, 5.3 and 5.0%, respectively. Our surface sediment-derived data provide a baseline for the analysis of future environmental variations of the lakes in the arid regions of northwest China, which are threatened by impacts of global climate change and regional water management

Dust emission reduction enhanced gas-to-particle conversion of ammonia in the North China Plain

Liu et al. found that the formation rate of particulate ammonium is slower in the atmosphere than that observed in the laboratory, while it is sped up due to an increase in aerosol acidity driven by an emission reduction of dust in North China Plain.Ammonium salt is an important component of particulate matter with aerodynamic diameter less than 2.5 mu m (PM2.5) and has significant impacts on air quality, climate, and natural ecosystems. However, a fundamental understanding of the conversion kinetics from ammonia to ammonium in unique environments of high aerosol loading is lacking. Here, we report the uptake coefficient of ammonia (gamma(NH3)) on ambient PM2.5 varying from 2.2 x 10(-4) to 6.0 x 10(-4) in the North China Plain. It is significantly lower than those on the model particles under simple conditions reported in the literature. The probability-weighted gamma(NH3) increases obviously, which is well explained by the annual decrease in aerosol pH due to the significant decline in alkali and alkali earth metal contents from the emission source of dust. Our results elaborate on the complex interactions between primary emissions and the secondary formation of aerosols and the important role of dust in atmospheric chemistry.Peer reviewe

Cone-beam CT functional imaging method by using volume integral model

In order to improve the precision of functional imaging of cone beam computed tomography (CBCT), this paper firstly uses the dynamic contrast enhancement tomography (DCE-CT) of the white rabbit as the measured object and establishes volume integral model to obtain the projection data. Then the optimization method is used to solve the optimal parameter pairs of the voxel time density curve (TDC). Finally, the results of the perfusion are obtained by the deconvolution method. The results show that the TDC correlation coefficient is 83.99% after, and the maximum of Spearman correlation coefficient of the perfusion parameter is 0.5125, and the projection time consumption is 7.633 seconds through the volume integral model. It can be seen that the volume integral model is closer to the real projection and it can obtain more accurate perfusion data

Immediate and Long-term Effects of Live Streaming Selling on Product Sales

Live streaming commerce has gained considerable traction in recent years, which transforms the traditional online shopping experience by enabling real-time interactions between streamers and customers with the leverage of live streaming technology. While existing studies have suggested that live streaming selling could enhance sales by increasing customers’ purchase intentions, scant research has confirmed this effect with large-scale empirical sales data. Additionally, extant literature failed to distinguish between the immediate and long-term impact of live steaming on product sales. Based on the data collected from Amazon Live and Amazon.com, this study examines the immediate and long-term influence of live streaming on product sales. By using discontinuous growth modeling, the preliminary results show that product sales will increase immediately after live streaming selling, but will have a declining trend in a long run, strongly supporting our hypotheses. These findings can provide significant theoretical and practical implications for live streaming commerce operation

Chromosome-level genome assembly of Microplitis manilae Ashmead, 1904 (Hymenoptera: Braconidae)

Abstract Microplitis manilae Ashmead (Hymenoptera: Braconidae) is an important parasitoid of agricultural pests in lepidopteran species. So far, two extant genome assembles from the genus Microplitis are fragmented. Here, we offered a high-quality genome assembly of M. manilae at the chromosome level with high accuracy and contiguity, assembled by ONT long-read, MGI-SEQ short-read, and Hi-C sequencing methods. The final assembled genome size was 282.85 Mb, with 268.17 Mb assigned to 11 pseudochromosomes. The scaffold N50 length was 25.23 Mb, and the complete BUSCO score was 98.61%. The genome contained 152.37 Mb of repetitive elements, representing 53.87% of the total genome size. We predicted 15,689 protein-coding genes, of which 13,580 genes were annotated functionally. Gene family evolution investigations of M. manilae revealed 615 expanded and 635 contracted gene families. The high-quality genome of M. manilae reported in this paper will be a useful genomic resource for research on parasitoid wasps in the future

Mitochondrial Genomes Yield Insights into the Basal Lineages of Ichneumonid Wasps (Hymenoptera: Ichneumonidae)

We obtained four mitochondrial genomes of Odontocolon sp., Xorides funiuensis, Euceros kiushuensis and Euceros serricornis, which represent the first two representatives from subfamily Eucerotinae and Xoridinae (Ichneumonidae), respectively. All of the 4 newly sequenced mitochondrial genomes contain 13 protein-coding genes (PCGs) and most 24 RNA genes. Furthermore, they all have novel tRNA rearrangement patterns comparing with published mitogenomes in Ichneumonidae. For the tRNA cluster trnI-trnQ-trnM, X. funiuensis is shuffled as trnM-trnI-trnQ with trnQ inversed, while Odontocolon sp. with a remote translocation of trnK, shuffling as trnI-trnM-trnQ. E. kiushuensis and E. serricornis shared the same cluster trnQ-trnY-trnW-trnC. Finally, we reconstructed the phylogenetic relationships among the sequenced subfamilies of Ichneumonidae based on nucleotides and amino acids sequences of 13 PCGs in mitochondrial genomes, and the results of both the maximum likelihood and Bayesian inference analyses highly support that Eucerotinae is the basal ichneumonid lineage rather than Xoridinae

Comparative Mitochondrial Genomics of 104 Darwin Wasps (Hymenoptera: Ichneumonidae) and Its Implication for Phylogeny

Ichneumonidae is one of the largest families of insects with a mega-diversity of specialized morphological and biological characteristics. We newly sequenced 92 mitochondrial genomes of ichneumonid wasps and found that they have a conserved base composition and a lower evolutionary rate than that of other families of parasitic Hymenoptera. There are 38 types of gene order in the ichneumonid mitochondrial genome, with 30 novel types identified in 104 ichneumonids. We also found that the rearrangement events occur more frequently in Ophioniformes than in Ichneumoniformes and Pimpliformes. Furthermore, the higher Ophioniformes and their relative lineages shared the transposition of trnL2 to trnI-trnQ-trnM tRNA cluster. We confirmed five higher-level groupings of Ichneumonidae: Brachycyrtiformes, Ichneumoniformes, Ophioniformes, Pimpliformes and Xoridiformes. Two formerly unplaced subfamilies, Eucerotinae and Microleptinae, were placed in Brachycyrtiformes and Ichneumoniformes, respectively. The results will improve our understanding of the diversity and evolution of Ichneumonidae