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Air pollution, especially the synergistic pollution of PM2.5 and O3, poses a severe threat to human life and production. The synergistic formation mechanism of PM2.5 and O3 pollution is relatively confirmed, while research on their spatiotemporal synergy is urgent. Based on remotely sensed interpretation data from 90 cities in the Yellow River Basin, we analyzed the synergistic evolution of PM2.5 and O3 concentrations during 2013–2020. Combined with the environmental Kuznets curve, we performed factor analysis using a panel regression model. The synergistic evolution pattern shows a gradual decrease in PM2.5 concentration and a gradual increase in O3 concentration. There is a strong spatial auto-correlation in the two pollutants' concentrations. The relationship between economy and PM2.5 concentration shows an "N-shaped" curve, while that between O3 concentration and economic development presents an inverse "N-shaped" curve. The environmental Kuznets curve shows that the deterioration of O3 pollution takes place later than the mitigation of PM2.5 pollution. Various factors have obvious heterogeneous effects on PM2.5 and O3 concentrations. Meanwhile, the sensitivity effect of per capita GDP on PM2.5 concentration in the midstream region is stronger than that in the upstream region, while the sensitivity effect of per capita GDP on O3 concentration is strongest in the midstream region than that in upstream and downstream region. [ABSTRACT FROM AUTHOR]

To study the morphological differences between and the evolutionary mechanisms driving the differentiation of geographically distinct populations of Gymnodiptychus dybowskii, 158 fish were collected from the Turks River and the Manas River in Xinjiang from 2020 to 2021 with the approval of the Academic Ethics Committee. The morphological characteristics of the fish were assessed using classical fish ecology methods such as traditional morphometric measurements and the framework approach. The results showed that the morphological characteristics of the populations in the Turks River and Manas River were significantly different; a one-way ANOVA revealed 22 highly significant differences (p < 0.01) and 1 significant difference (p < 0.05) among the 33 morphological traits of the observed populations, and a principal component analysis revealed that there was no overlap between the two populations of G. dybowskii. The main characteristics associated with principle component 1 were the terminus of the dorsal fin to the ventral origin of the caudal fin (D—F), the dorsal origin of the caudal fin to the origin of the anal fin (E—H), and the insertion of the pectoral fin to the terminus of the pectoral fin (J—K); the main factors associated with principal component 2 were the body height (BD), the terminus of the dorsal fin to the insertion of the pelvic fin (D—I), the caudal peduncle height (CPH), and the tip of the snout to the last end of the frontal maxilla (A—B); and the main traits associated with principle component 3 were the terminus of the anal fin to the origin of the anal fin (G—H), the body width (BW), the insertion of the pelvic fin to the terminus of the pelvic (I—L), the insertion of the pectoral fin to the terminus of the pectoral fin (J—K), and the insertion of the pelvic fin to the insertion of the pectoral fin (I—J). An OPLS-DA revealed that the two populations could be wholly separated and that the intergroup growth traits of the Manas River population were different and significantly greater than those of the Turks River population. The discriminant functions of the Turks River and Manas River populations of G. dybowskii were as follows: YT = −432.033 + 1787.748X1 + 826.517X2 + 249.002X3 + 1183.050X4 + 554.934X5 + 999.296X6 + 627.428X7; YM = −569.819 + 2041.044X1 + 344.942X2 + 333.737X3 + 940.512X4 + 348.222X5 + 1167.770X6 + 1015.904X7. According to a coefficient of variation analysis, a total of nine traits, namely, EI/BL, C-D/BL, E-F/BL, F-H/BL, H-I/BL, C-J/BL, D-I/BL, D-H/BL, and D-F/BL, had a CD > 1.28, indicating that the differences in these nine traits had reached the subspecies level. The results showed that G. dybowskii significantly differed between the two geographically distinct populations in the Turks River and the Manas River and have differentiated to the subspecies level. This study provides a basis for a better investigation of the population structure of highland endemic fishes and the mechanisms by which they diverged and lays a foundation for developing and utilizing germplasm resources from endemic fishes in Xinjiang. [ABSTRACT FROM AUTHOR]

The age, growth, and reproduction of Schizothorax pseudaksaiensis (Herzenstein, 1889), a second-level key protected aquatic species in Xinjiang, were studied using fish ecology methods, and the biological characteristics of its population are discussed. A total of 735 specimens were collected on a seasonal basis from 2021 to 2022 using cages and nets in the Turks River. The fish length ranged from 47.30 mm to 538.60 mm, and the minimum age and maximum age were 1 years old and 23 years old, respectively. The fitting correlations revealed that S. pseudaksaiensis is a uniformly growing fish. The ages at the inflection point for S. pseudaksaiensis were 22.28 (female) and 19.55 (male). The sex ratio was 0.89 (females):1 (males), and the spawning period occurred from April to July. The absolute fecundity was 55,652.01 ± 25,468.78 eggs per individual, and the relative fecundity was 25.92 ± 10.69 eggs per gram. This study provides life history trait data for S. pseudaksaiensis and has theoretical and practical importance for maintaining population dynamics and fishery ecological balance. Additionally, a basis for the protection of fishery germplasm plateau resources is provided. [ABSTRACT FROM AUTHOR]

Simple Summary: This study investigates the evolutionary dynamics of macroinvertebrate functional traits within the Irtysh River Basin under the influence of urbanization. Through comprehensive field assessments and data analysis, we document a significant transition process toward pollution-tolerant functional characteristics in macroinvertebrates, coinciding with the rapid pace of urban development. Simultaneously, the community undergoes a gradual transition, marked by an increase in pollution-tolerant taxa. Urbanization-induced environmental pollution and waste discharge emerge as prominent catalysts, accelerating the observed changes in macroinvertebrate communities and functional traits. Our findings underscore the critical role of anthropogenic factors in aquatic ecosystems and highlight the imperative of strategic management strategies to mitigate these effects. This study contributes to a deeper understanding of the intricate interplay among urbanization, environmental change, and benthic organism responses, providing essential insights for sustainable river management amidst urban expansion. Little is known about how changes in the biodiversity and functional traits of macroinvertebrates in rivers respond to the responses of anthropic pressures and their driving factors. Macroinvertebrates were sampled at 17 sites in the Irtysh River Basin and classified macroinvertebrates into 10 traits and 38 categories between May and August 2022. Then, we performed R-mode linked to Q-mode (RLQ) analysis and calculated functional richness, evenness, divergence, and Rao's quadratic entropy (RaoQ) for each site and community-weighted means for each trait category. Our results indicated that there were pronounced alterations in species variability in the urban region. Functional divergence indicated fierce competition among species and considerable niche overlap in the urban region. Functional evenness indicated that species abundance distribution and interspecific functional distance were not uniform in the urban region. Functional richness indicated that the urban region was the strongest region in terms of niche occupation, resource utilization, and buffering capacity for environmental fluctuations. Rao's quadratic entropy showed that the trait difference of macroinvertebrates was the largest in all regions, which was caused by the gradient environmental difference. Research has revealed that urbanization significantly influences the evolutionary trajectory of macroinvertebrate fauna, culminating in an upsurge in pollution-tolerant species and a convergence of functional traits. We recommend strengthening the control of urban and industrial pollution and wise planning and management of land and water resources to mitigate the impact of anthropogenic destruction on habitat fragmentation in the Irtysh River Basin. [ABSTRACT FROM AUTHOR]

In order to resolve the long-standing controversy surrounding the relationships within the Triplophysa genus, we conducted an extensive analysis of the complete mitogenome of Triplophysa labiata using DNBSEQ short reads. Additionally, we reconstructed the phylogeny of the Nemacheilidae family using mitogenome data. By comparing all available mitogenomes within the Triplophysa genus, we gained valuable insights into its evolutionary history. Our findings revealed that the mitogenome sequence of T. labiata is circular, spanning a length of 16,573 bp. It encompasses 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs), and a control region (D-loop). Among the PCGs, the start codon ATG was commonly observed, except in cox1, while the stop codons TAA/TAG/T were found in all PCGs. Furthermore, purifying selection was evident across all PCGs. Utilizing maximum likelihood (ML) methods, we employed the 13 PCGs and the concatenated nucleotide sequences of 30 Triplophysa mitogenomes to infer the phylogeny. Our results strongly supported the division of the Triplophysa genus into four primary clades. Notably, our study provides the first evidence of the close relationship between T. labiata and T. dorsalis. These findings serve as a significant foundation for future investigations into the mitogenomics and phylogeny of Nemacheilidae fishes, paving the way for further advancements in this field of research. [ABSTRACT FROM AUTHOR]

Currently, Chinese cities are experiencing both overall growth and localized shrinkage. Therefore, it becomes crucial to quantify urban shrinkage and explore the transformation and sustainable development of shrinking cities from the perspective of urban resilience. This study focuses on the three provinces of Northeast China, which are representative areas of urban shrinkage, as its research subjects. Employing the analytic hierarchy process, a comprehensive evaluation system for urban shrinkage is constructed based on three dimensions: population, economy, and space. Furthermore, urban resilience is scientifically measured from four aspects: economy, society, ecology, and infrastructure. The study analyzes the spatiotemporal evolution characteristics of urban shrinkage and urban resilience in the three northeastern provinces from 2012 to 2018. It also examines the impact of urban shrinkage on urban resilience through regression analysis and mediation models. The results indicate the following: (1) Half of the cities in the three northeastern provinces experienced shrinkage, although the extent of shrinkage decreased with the implementation of the Northeast China revitalization strategy. Population-related shrinkage was the most extensive and continued to expand, while economy-related shrinkage was the most severe, and space-related shrinkage was the least severe. (2) The resilience of shrinking cities was lower than the average level. Population-shrinking cities and economy-shrinking cities exhibited low levels of economic resilience, and the gap between them continued to widen. Space-shrinking cities generally had low infrastructure resilience. (3) The urban shrinkage index had a significant positive impact on the urban resilience index, mediated through intermediary variables, such as innovation capability and cultural development. Notably, both the direct and indirect effects of innovation capability were the greatest. Population-related shrinkage had the largest impact on urban resilience, while more intermediary variables of economy-related shrinkage passed the significance test. [ABSTRACT FROM AUTHOR]

The emergence and enduring diffusion of COVID-19 has had a dramatic impact on cities worldwide. The scientific aim of this study was to introduce geospatial thinking to research related to infectious diseases, while the practical aim was to explore the impact on population movements and urban linkages in the longer term following a pandemic outbreak. Therefore, this study took 366 cities in China as the research subjects while exploring the relationship between urban contact and the outbreak of the pandemic from both national and regional perspectives using social network analysis (SNA), Pearson correlation analysis and multi-scale geographically weighted regression (MGWR) modeling. The results revealed that the number of COVID-19 infections in China fluctuated with strain variation over the study period; the urban contact network exhibited a significant trend of recovery. The pandemic had a hindering effect on national urban contact, and this effect weakened progressively. Meanwhile, the effect exhibited significant spatial heterogeneity, with a weakening effect in the eastern region ≈ northeast region > central region > western region, indicating a decreasing phenomenon from coastal to inland areas. Moreover, the four major economic regions in China featured border barrier effects, whereby urban contact networks constituted by cross-regional flows were more sensitive to the development of the pandemic. The geostatistical approach adopted in this study related to infectious disease and urban linkages can be used in other regions, and its findings provide a reference for China and other countries around the world to respond to major public health events. [ABSTRACT FROM AUTHOR]

The electrical performance of the feed array is degraded because of the position deviation of the array elements caused by manufacturing and processing, which cannot meet the high performance feeding requirements of large feed arrays. In this paper, a radiation field model of the helical antenna array considering the position deviation of array elements is proposed to investigate the influence law of position deviation on the electrical performance of the feed array. With the established model, the rectangular planar array and the circular array of the helical antenna with a radiating cup are discussed and the relationship between electrical performance index and position deviation is established by numerical analysis and curve fitting method. The research results show that the position deviation of the antenna array elements will lead to the rise of the sidelobe level, the deviation of the beam pointing, and the increase of the return loss. The valuable simulation results provided by this work can be used in antenna engineering, guiding antenna designers to set optimal parameters when fabricating antennae. [ABSTRACT FROM AUTHOR]

Natural and socioeconomic variables have an impact on ecosystem services (ESs). The ESs trade-offs/synergies are informed by the reality that the same inputs have varying impacts on different ESs. Changing scales and time can alter dominant drivers and biophysical linkages of ESs, affecting their relationships. Although it is often assumed that ES relationships vary across scales, quantitatively testing this assumption with multiple ES is rare. Therefore, this study evaluated the five key ESs in the Pearl River Delta (PRD) from 1990 to 2015. We also employed a statistical approach to investigate the temporal variations, scale dependency, and spatial heterogeneity of ES trade-offs and synergies. The results demonstrated that: (1) The PRD's synergetic interaction among ESs has been steadily improving over time; (2) The interaction between ESs dramatically altered as the research scale increased; (3) We discovered that the linkages among the soil conservation (SC), carbon sequestration (CS), water yield (WY), and habitat quality (HQ) were primarily synergistic. ESs of SC, CS, WY, and HQ were found to have negative correlations with grain production. This study will strengthen the understanding of the temporal changes and spatial scales of ESs relationships for decision-makers, which is beneficial to ecosystem management. [ABSTRACT FROM AUTHOR]

In metal processing, exit burrs are usually inevitable, which is a huge challenge for high-precision manufacturing. This paper innovatively proposes an ice boundary constraint (IBC) method to actively suppress exit burrs to obtain better workpiece edge quality. Firstly, the formation mechanism of the exits burr is analyzed from the perspective of material flow at the edge of the workpiece, and the principle of the IBC method is explained. Secondly, a finite element model (FEM) is established to analyze the stress distribution and flow at the edge of the workpiece, so as to reveal the suppression mechanism of IBC on the exit burrs. Finally, the feasibility of IBC method and the validity of FEM are verified by the milling experiments. The experimental results show that the IBC method can reduce the exit burr height by 51.4% on average, and FEM can effectively predict the height of the exit burr. The IBC method proposed in this study can provide some reference and guidance for the active suppression of exit burrs in industry. [ABSTRACT FROM AUTHOR]

Following the appearance of urban shrinkage in Western countries, scholars have taken note of increasing amounts of urban shrinkage with significant regional characteristics in China in recent years. Focusing on the Yellow River Basin, this study comprehensively measured prefecture-level and county-level city shrinkage based on China's fifth, sixth and seventh national census data. Furthermore, the spatiotemporal patterns, types and modes of urban shrinkage were analyzed, and the factors influencing urban shrinkage were explored using a multiple linear regression model and a sorting model. The study results show that the number of shrinking cities and the shrinking degree significantly increased at the prefecture and county levels in the last 20 years. The identified shrinking cities are concentrated in the upper and middle reaches of the river basin, spatially configured around major cities and along the high-speed railway line. The regional pattern shows a typical "core–periphery" characteristic. Peripheral shrinkage is the main mode in which cities shrink. The strength and speed of economic development and industrial transformation positively affect urban shrinkage; the ageing degree, high-speed railway opening and other factors negatively affect urban shrinkage. [ABSTRACT FROM AUTHOR]

China's rural areas face population loss and expanded residential land in the context of rapid urbanization. The increasing hollowing of villages leads to extensive land use, making it necessary to optimize and consolidate rural settlements immediately. Therefore, how to choose an appropriate development model for rural settlements is at issue. This article builds a theoretical development model for rural settlements based on their primary development conditions and spatial patterns. It determines the development model according to the classification matrix formed by interweaving different elements in each dimension. Finally, it demonstrates the model through a case study on Pingyin County, China. The empirical findings for Pingyin County are as follows. (1) The scale of rural settlements increased from 2010 to 2020, and the agglomeration and spatial correlation intensified, but they tended to be irregular. (2) The various elements of the development foundation showed apparent spatial differentiation, and the spatial distribution of rural settlements at different levels presented a core–edge structure. (3) The development of rural settlements was reduced to six models: in-situ urbanization, satellite urbanization, competitive-industry-driven, characteristic-tourism-driven, modern-agriculture-driven, and village relocation. Finally, the article proposes different development paths for different development models. [ABSTRACT FROM AUTHOR]

Currently, urban crises are spreading, even tending to be magnified along the urban networks. Improving urban network resilience can effectively reduce the loss and cope with sudden disasters. Based on the dimensions of regional resilience and the framework of urban network, a new evaluation system of network resilience, including economic, social, and engineering networks, was established to assess the network resilience of the Guangdong–Hong Kong–Macao Greater Bay Area (GBA) from a structural perspective. We analyzed the spatial characteristics and influencing factors of network resilience using social network analysis and quadratic assignment procedure. The results were as follows: (1) regional difference was biggest in GBA's economic network strength while smallest in its transportation network strength, and the east bank of the Pearl River represented an extremely resilient connection axis; (2) the structures of network resilience and its subsystems were heterogeneous, and the connection paths of network resilience were more heterogeneous and diversified than those of the subsystems; (3) network resilience presented an obvious core–edge structure, and the spatial correlation and spillover effect between blocks were substantial; and (4) geographical proximity, as well as differences in economic development, urban agglomeration, and market development, had a significant impact on network resilience. This study provides a more systematic approach to evaluate the regional network resilience, and the results provide references for the construction of bay areas in developing countries. [ABSTRACT FROM AUTHOR]

Industrial structure and regional innovation have a significant impact on emissions. This study explores, from the multivariate coupling and spatial perspectives, the degree of coupling coordination between three factors: industrial structure, carbon emissions, and regional innovation of 97 counties in Shandong Province, China from 2000 to 2017. On the basis of global spatial autocorrelation and cold and hot spots, this article analyzes the spatial characteristics and aggregation effects of coupled and coordinated development within each region. The results are as follows. (1) The coupling degree between carbon emissions, industrial structure, and regional innovation in these counties fluctuated upward from 2000 to 2017. Coupling coordination progressed from low coordination to basic coordination. Regional differences in coupling coordination degree are evident, showing a stepped spatial distribution pattern with high levels in the east and low levels in the west. (2) During the study period, the coupling coordination showed a positive correlation in spatial distribution. Moran's I varies from 0.057 to 0.305 on a global basis. Spatial clustering is characterized by agglomeration of cold spots and hot spots. (3) The coupling coordination exhibited significant spatial differentiation. The hot spots were distributed in the eastern part, while the cold spots were located in the western part. The results of this study suggest that the counties in Shandong Province should promote industrial structure upgrades and enhance regional innovation to reduce carbon emissions. [ABSTRACT FROM AUTHOR]

Spectral analysis of terrain height variance is conducive to quantitatively study the terrain characteristics and grid-size selection for mesoscale models. Improved topographic resolutions can lead to the variations of terrain characteristics and the appropriate grid size for a fixed analyzed area. Spectral methods of one-dimensional weighted average and arithmetic mean were used to investigate the specific impact on the distribution of terrain spectra and grid-size selection for mesoscale models of the landslide-prone areas in western Sichuan. The results indicate that the maximum spectral energy (the variance of the terrain height series) of 30″ resolution (R1) is larger than that of 90 m resolution (R2), indicating a gentler undulation of terrain for R2. The spectral curve of R2 almost overlaps with that of R1 because the difference in topographic resolution does not change the dominant distribution of the topography. Their differing spectral energies at longer wavelengths are related to the majority of grid points of R2 distributed at shorter wavelength bands. A least squares fit in the form of S = a λ b was used to estimate the decreasing trend of the spectral distribution. The difference in spectral slope between R1 and R2 is mainly caused by the spectral energy of R2 at shorter wavelengths. The exponent b is connected with grid-size selection for mesoscale models. A universal horizontal grid size of 2.5 km for R1 and 1.9 km for R2 are required to resolve 95% of the terrain height variance for a mesoscale model application without a subgrid-scale parameterization. The simulation tests show that the improved topographic resolution appears to perform better in reproducing precipitation, which is probably related to the finer details of the terrain recognized by the model. [ABSTRACT FROM AUTHOR]

In recent years, the construction of small towns in China has faced many challenges, hindering the sustainable development of small towns. This paper proposes that the traditional development model of small towns no longer meets the current demands, and it urgently needs updating. In the past two years, there has been an increase in the construction of characteristic small towns in China. This is a good beginning for the transformation development of small towns and would bring new opportunities. However, some problems have developed. One example is the emergence of the "blind town", which means the governors cultivate a featured town blindly without objectively considering the reality of that area. These decisions have a negative impact on the future sustainable development of small towns. Therefore, the governors need to consider the basic conditions of the area, perform a scientific assessment, and present a clear cultivation strategy. This paper presents a preliminary scientific method for the characteristic development mode of small towns with "explore characteristic–evaluate characteristic–nurture characteristic" as the main line, which would be conducive to the characteristic transformation for the steady and sustainable development of small towns in China. [ABSTRACT FROM AUTHOR]

Supercritical fluid carbon dioxide (SF-CO2) was used to extract oil from Elaeagnus mollis Diels (E. mollis Diels) seed and its antioxidant ability was also investigated. The effect of extraction pressure (20–35 MPa), extraction temperature (35–65 °C), extraction time (90–180 min) and seed particle size (40–100 mesh) on the oil yield were studied. An orthogonal experiment was conducted to determine the best operating conditions for the maximum extraction oil yield. Based on the optimum conditions, the maximum yield reached 29.35% at 30 MPa, 50 °C, 150 min, 80 mesh seed particle size and 40 g/min SF-CO2 flow rate. The E. mollis Diels seed (EDS) oil obtained under optimal SF-CO2 extraction conditions had higher unsaturated fatty acid content (91.89%), higher vitamin E content (96.24 ± 3.01 mg/100 g) and higher total phytosterols content (364.34 ± 4.86 mg/100 g) than that extracted by Soxhlet extraction (SE) and cold pressing (CP) methods. The antioxidant activity of the EDS oil was measured by DPPH and hydroxyl radical scavenging test. EDS oil extracted by different methods exhibited a dose-dependent antioxidant ability, with IC50 values of no significant differences. Based on the results of correlation between bioactive compounds, lupeol and γ-tocopherol was the most important antioxidant in EDS oil. [ABSTRACT FROM AUTHOR]