Search Results (599)

This study incorporates environmental regulation, green technological innovation, and industrial structure upgrading into a unified analytical framework. Collecting panel data from 71 core prefecture-level cities in the Chengdu–Chongqing, Middle Reaches of the Yangtze River and Yangtze River Delta urban agglomerations from 2011 to 2023, adopting fixed-effects, mediation, and moderation models to investigate how environmental regulation and green technological innovation affect industrial structure upgrading, through which mechanisms these effects occur, and how inclusive digital finance moderates these relationships. The findings reveal that command-and-control and guidance-based environmental regulations all exert positive effects on industrial structure upgrading. Green technological innovation serves as a mediating mechanism through which command-and-control environmental regulation promotes industrial structure upgrading. Inclusive digital finance acts as a boundary condition shaping the effect of environmental regulation on industrial structure upgrading. Further heterogeneity analysis reveals regional variation in how different types of environmental regulation affect industrial structure upgrading. This study proposes policy recommendations that urban agglomerations should attach greater importance to green innovation, enhance the breadth and depth of inclusive digital finance utilization, and establish appropriate local environmental regulatory support systems so as to promote industrial structure upgrading. Full article

To clarify the transformation patterns and driving mechanisms of the explicit and implicit morphology of rural settlements in peri-urban areas of large mountainous cities in Southwest China, this study examines the central urban area of Chongqing. Using land-use, point-of-interest (POI), socio-economic and digital elevation model (DEM) data from 2008 to 2024, we constructed an evaluation system for explicit and implicit rural settlement morphology. Kernel density estimation, the Mann–Kendall test and the moving t-test were used to identify morphological evolution, while the coupling coordination degree model and structural equation modeling (SEM) were applied to examine coordination relationships and driving mechanisms. The results show that: (1) during the study period, explicit morphology showed continuous contraction, whereas implicit morphology exhibited fluctuating improvement and polarized differentiation, indicating an overall gradual transformation; (2) no statistically significant abrupt changes were detected in either morphology, while temporal changes in coupling coordination divided the process into three stages—stable coordination, intensified imbalance and weak recovery—reflecting structural adjustment; (3) the coupling coordination degree declined overall, shifting from primary coordination towards near imbalance and indicating an uncoordinated transformation characterized by advanced contraction of explicit morphology and lagged improvement of implicit morphology; and (4) SEM results indicate that transportation infrastructure is the core driver of morphological transformation, with a significant positive effect on explicit morphology and a significant negative effect on implicit morphology. Natural factors positively support both morphologies, socio-economic factors exert negative or weak effects, and public services and real estate negatively affect explicit morphology but significantly promote implicit morphology. These findings provide a scientific basis for optimizing the layout and improving the functions of rural settlements in mountainous cities. Full article

Inbound tourism has become an important indicator of destination openness, service capacity, cultural communication, and sustainable governance. However, existing evaluations often separate visitor experience, destination competitiveness, and sustainability, making it difficult to diagnose how service quality supports long-term competitiveness. This study develops a sustainability-oriented framework for evaluating inbound tourism service quality in 10 representative Chinese cities. Nineteen indicators are organized into four dimensions: basic service provision, cultural and experiential perception, safety and emergency response, and sustainable and resilient development. A TIFN-AHP-TOPSIS model is used to integrate official statistics, public tourism information, online-review evidence, and expert judgments while retaining uncertainty and hesitation in qualitative assessments. The results show that Shanghai, Beijing, and Hangzhou form the leading tier; Shenzhen, Chengdu, Guangzhou, Sanya, and Xiamen form the balanced tier; and Xi’an and Chongqing form the potential tier. Robustness checks based on risk-preference adjustment, entropy-weighted TOPSIS, grey relational TOPSIS, and perception-indicator perturbation confirm the stability of the tier classification. The findings suggest that inbound tourism competitiveness depends not only on transport access and reception capacity but also on cultural interpretation, digital convenience, safety governance, ecological quality, and resilience. The framework provides a diagnostic tool for improving sustainable destination competitiveness. Full article

Enhancing urban carbon productivity (UCP) is crucial for achieving the dual carbon goals in China. This study investigates the spatiotemporal patterns and underlying drivers of UCP in the Yangtze River Economic Belt (YREB) from 2010 and 2020. Utilizing a comprehensive dataset of 110 cities, we employ kernel density estimation, spatial autocorrelation analysis, and the Spatial Durbin Model (SDM). The results reveal a significant overall improvement in UCP alongside intensified internal disparities and a fundamental spatial restructuring—from a monocentric eastern-led pattern to a multipolar network driven by the Yangtze River Delta, middle Yangtze, and Chengdu-Chongqing agglomerations. The SDM decomposition reveals a shift in core drivers towards green technological innovation and advanced industrial structure, while energy consumption remains the primary constraint. Crucially, complex spatial spillover effects are identified: factors like advanced industrial structure and digital governance are associated with positive synergistic spillovers, whereas government intervention (government public budget expenditure) and urban sprawl exhibit negative competitive spillovers, collectively corresponding to the polarized regional pattern. Furthermore, urban form shows strong spatial externalities: urban compactness is linked to a “local-neighborhood” double dividend, while urban sprawl is associated with a “local-neighborhood” double curse. The influence of digital factors appears to evolve from early widespread spillovers to later localized deepening. The findings suggest the necessity of implementing spatially differentiated policies, strengthening regional collaborative governance to manage spatial externalities, and promoting compact regional spatial planning to foster synergistic and equitable low-carbon transitions across the YREB. Full article

Flavonoids are essential secondary metabolites that predominantly affect flower pigmentation in plants. Understanding the molecular mechanisms underlying flower color divergence is crucial for ornamental plant breeding. This study aimed to elucidate the factors responsible for the differences in color between white-petaled Cosmos bipinnatus and orange-petaled Cosmos sulphureus. We employed an integrated approach combining untargeted LC–MS/MS metabolomics and high-throughput transcriptome sequencing of fresh petals to analyze pigment composition and differential gene expression. Petal pigment extraction, total flavonoid quantification, and metabolomic profiling consistently revealed that differences in flavonoid abundance are responsible for flower color divergence between the two species. In contrast, carotenoids, previously considered potential contributors to flower coloration, were neither evident in the oil phase of the pigment extracts nor detected by metabolomic analysis. Flavonoid compounds accumulated at relatively high levels in the orange petals of C. sulphureus, reaching 11.36 times that of C. bipinnatus, contributing to its bright appearance. Transcriptomic analysis revealed differences in gene expression patterns between the two species, highlighting key candidate genes involved in the flavonoid biosynthesis pathway, such as chalcone synthase. These findings indicate that the orange coloration of C. sulphureus may be associated with CHS-regulated accumulation of naringenin chalcone and downstream compounds in the flavonoid metabolic pathway after CHS, providing valuable theoretical support for a deeper understanding of the causes underlying the differences in flower color between C. bipinnatus and the orange-petaled C. sulphureus. Full article

Urban tourism communities activate local resources through spaces shared by residents and tourists, yet the inherent spatial overlap and functional complexity of these areas often generate conflicts. Existing research has predominantly focused on traditional scenic areas, heritage sites, or cities affected by overtourism, with comparatively little attention to urban tourism communities. This study draws on three tourism communities in Chongqing, China, employing street-intercept interviews and spatial analysis to investigate the forms and spatial characteristics of resident–tourist conflict. The findings indicate that such conflicts manifest across four dimensions: management conflict, economic conflict, resource and environmental conflict, and socio-cultural conflict. Conflicts are more likely to occur in areas where tourist activities intersect with residents’ daily routines, and different conflict types exhibit distinct spatial patterns. Furthermore, residents are more sensitive to these conflicts than tourists. By adopting a dual resident–tourist perspective, this study advances understanding of the tensions in high-density, high-mobility urban tourism communities and provides empirical insights to inform their sustainable development. Full article

Using a sample of 297 prefecture-level cities in China from 2010 to 2022 and drawing on green patent transfer data, this study constructs a directed weighted network and applies social network analysis, a modified gravity model, and quadratic assignment procedure (QAP) regression to examine the spatial structural evolution, node topology characteristics, and driving factors of China’s green technology transfer (GTT) network. The results show that: (1) From 2010 to 2022, the number of nodes grew from 249 to 292, network coverage increased from 83.8% to 98.3%, and the number of edges expanded by a factor of 14.47. Network density and average degree also rose markedly. The spatial structure evolved from an initially sparse and fragmented configuration into a polycentric complex network centered on the Beijing–Tianjin–Hebei region, the Yangtze River Delta, and the Chengdu–Chongqing economic circle. (2) In terms of node topology, the intermediary and control capacities of cities exhibit dynamic changes, with central and western cities gaining growing influence within the network. (3) Cohesive subgroup analysis identifies four functional blocks, revealing a multi-level technology spillover path of “core—secondary—regional—peripheral.” (4) QAP regression further identifies the digital economy, geographic location, high-speed rail mileage, industrial structure, and government environmental concern as key drivers of network formation and evolution. This study offers a new perspective on understanding cross-regional green technology transfer and provides theoretical grounding and policy references for promoting regional collaborative innovation and green low-carbon development. Full article

In the context of global climate change and rapid urbanization, urban outdoor thermal environment issues in summer have become increasingly severe. Shading has been widely recognized as an effective strategy for improving outdoor thermal comfort, yet existing evaluation methods still suffer from limitations in adaptability and accuracy. Taking Chongqing, a typical hot-humid city in China, as a case study, this paper proposes an evaluation method that accounts for human thermal adaptation, introducing three complementary indicators, namely Universal Thermal Climate Index Load (UTCIL), cumulative UTCIL (cUTCIL), and Heat Stress Duration (HSD). Focusing on four shading-related urban canyon morphological factors—orientation, aspect ratio (H/W), building asymmetry, and leaf area index (LAI) of street trees—a series of simulation scenarios was designed to quantitatively explore their impacts on summer outdoor thermal comfort. The applicability and reliability of the ENVI-met model for block-scale outdoor thermal environment simulation were validated by comparing field-measured microclimate data with simulation results. The findings demonstrate that all four morphological factors substantially influence the outdoor thermal environment. Canyon orientation considerably affects thermal comfort, with a 30° clockwise deviation from the north–south yielding optimal conditions, whereas the east–west (90°) orientation produces the poorest thermal environment, with a maximum UTCI of approximately 48.9 °C. For aspect ratio, thermal comfort improves continuously as H/W increases, with the benefit stabilizing beyond H/W = 3.5. Building asymmetry also plays a notable role: raising building height on one side can effectively reduce outdoor thermal stress, and canyons with taller west-side buildings show better thermal performance under the same asymmetry ratio. Furthermore, street tree shading and aspect ratio exhibit a synergistic cooling effect, where high LAI (e.g., 4.77) reduces UTCI_max by approximately 1.8 °C at H/W = 1, but this benefit diminishes as H/W increases. The optimal outdoor thermal environment is achieved through the combination of a high aspect ratio and high LAI. These findings provide a quantitative basis and design references for optimizing outdoor thermal comfort in Chongqing. In addition, the quantitative evaluation proposed method can offer a methodological reference for other hot-humid regions. Full article

Weekday commuting and weekend recreation are two mobility domains through which urban spatial structure shapes residents’ well-being and urban functioning, yet direct empirical evidence on how they are related remains limited. This study investigates how weekday commuting costs and weekend recreational mobility conditions are related within a jobs–housing–recreation spatial framework, using individual-level location-based services (LBS) data from the central urban area of Chongqing, China. Generalized additive models reveal a nonlinear and range-dependent commuting–recreation relationship. Distance-based and driving-time specifications provide the main evidence for a U-shaped relationship, whereas transit-time specifications do not clearly reproduce this pattern, reflecting short-distance cost overestimation and spatially shared public-transport constraints rather than realised mobility conditions. From a spatial-configuration perspective, this pattern suggests that work-related and recreational mobility conditions are unevenly combined across residential locations, rather than simply aligned or opposed. It also suggests that relatively favourable commuting and recreational mobility conditions can coexist within some residential contexts. Rather than establishing a universal rule, the Chongqing case provides a testable hypothesis that may be relevant to large cities with uneven and partially aligned employment, housing, transport, and recreational opportunities. The study provides an empirical entry point for integrated spatial-performance diagnosis and future evaluation of alternative jobs–housing–recreation configurations. Full article

Plant architecture optimization is central to high-yield crop breeding. The number of branches in Brassica napus (B. napus) determines canopy structure, light use efficiency, and yield. The transcription factor BRANCHED1 (BRC1) integrates multiple signals to negatively regulate branching. This study characterized five BnaBRC1 homologs in B. napus via bioinformatics, expression profiling, and CRISPR/Cas9 editing. All BnaBRC1s contain a conserved TCP domain, and their promoters are enriched with light-responsive and hormone-responsive cis-acting elements. BnaA01.BRC1 is highly expressed in leaves, stem nodes, roots, and siliques, and its transcription is coordinately regulated by low light, sucrose, and exogenous cytokinin, and gibberellin (GA) signals. Functional analysis showed that overexpression of BnaA01.BRC1 suppressed branching, whereas CRISPR/Cas9-mediated knockout of BnaBRC1 substantially increased branch number. In basal axillary buds, high BnaBRC1 expression was accompanied by upregulation of GA-inactivating GIBBERELLIN 2 OXIDASEs and the GA signaling negative regulator SPINDLY, and no direct interaction was detected between BnaA01.BRC1 and DELLA proteins, suggesting indirect regulation of branching via GA homeostasis. Collectively, this study demonstrates the pivotal role of BnaA01.BRC1 in branching regulation and provides a genetic resource and theoretical basis for plant architecture optimization and multi-branch germplasm innovation in B. napus. Full article

Although existing studies have shown that AI recommendation systems have potential in enhancing consumers’ purchase intention, there remains a lack of systematic research. This study aims to explore how the interaction between information presentation formats and AI role types influences consumers’ purchase intention. Based on metacognitive experience theory, two experiments are designed to analyze processing fluency as a mediator and consumers’ AI knowledge as a moderator. The results reveal that the interaction between information presentation format and AI role type significantly affects consumers’ purchase intention, while their separate effects are insignificant. Different from existing studies on separate factors, this study demonstrates that AI interactive marketing performance hinges on the matching of design and role positioning. This study extends the application of the theory of metacognitive experiences in the field of human–AI interaction and provides targeted recommendations for the interface design of AI recommendation systems. Full article

Teas processed from specialty-colored tea leaves possess distinctive quality profiles shaped by their volatile and non-volatile compounds, which serve as critical metrics for evaluating tea cultivars. In this study, we comprehensively characterized the quality attributes of flat green teas produced from three tea cultivars—green-leaved ‘FDDB’, yellow-leaved ‘ZH2’, and purple-leaved ‘ZJ’—using an integrated analytical approach including sensory evaluation, widely targeted metabolomics, GC-E-nose, and HS-SPME-GC-MS. Sensory evaluation revealed distinct sensory characteristics among teas processed from the three cultivars with different leaf colors. GC-E-nose analysis further confirmed that the aroma profiles of these tea samples could be clearly distinguished based on leaf color. Metabolomic analysis identified a total of 2050 non-volatile compounds, among which 18 amino acids, 5 phenolic acids, and 4 flavonoids were pinpointed as key contributors to the unique taste profiles of infusions from ZH2 and ZJ teas. Additionally, a total of 1100 volatile compounds were detected, with 94, 75, and 90 key aroma-active compounds identified in FDDB, ZH2, and ZJ teas, respectively. Collectively, in this study, systematic analysis revealed significant differences in both volatile and non-volatile chemical compositions across the three tea cultivars. These findings provide a scientific foundation for understanding the processing suitability and quality formation mechanisms of tea cultivars with distinct leaf colors. Full article

This study aimed to investigate how mulberry leaf powders from different mulberry varieties influenced the quality of artificial diet for domestic silkworms. Using metabolomics, we examined the possible reasons why silkworm rearing performance varied, and provided new research ideas for improving diet quality. Forage mulberry leaves differed from grafted mulberry leaves in metabolic pathways related to fatty acids, amino acids, and vitamin C. Forage mulberry leaf powder showed considerably decreased amounts of vitamin C, serine, linoleic acid, and linolenic acid, all of which are required for the production of silk proteins and their intermediates. A considerable increase in 1-deoxynojirimycin (DNJ) content was observed. The feeding characteristics of silkworms led to decreased DNJ tolerance and lower quality of silkworm diet made from forage mulberry leaf powder compared to that made from grafted mulberry leaf powder. Furthermore, the body weight during the silk-spinning stage, cocoon weight, and Cocoon shell ratio of the reared silkworms were all markedly reduced. Using mulberry leaf powder would require addressing the problem of reduced DNJ tolerance in silkworms owing to the changes in their diet, in addition to improving the composition of the silkworm diet based on the characteristics of the mulberry leaf powder. Full article

To address the problems of easy cracking and the difficulty in balancing construction schedule and structural quality in the construction of ultra-long concrete slabs, this paper takes the ultra-long floor slab project of an inpatient building in the Science City Campus of Chongqing University Cancer Hospital as the research object, and conducts research on temperature and crack control in the construction of the alternative bay method. The key structural mechanical parameters are determined through theoretical calculation. The temperature and deformation changes during the whole process of concrete pouring are tracked by combining on-site monitoring and finite element simulation, and the effects of different construction parameters are compared and analyzed. The results show that when the alternative bay method is adopted, the overall temperature distribution of the floor slab is uniform, and there are obvious differences in deformation at different positions. The center of the first-poured slab has smaller deformation, the beam side has larger deformation, the later-poured slab has larger overall deformation, and tensile deformation occurs on both sides of the construction joint. Reasonably dividing the pouring blocks, optimizing the pouring sequence and extending the pouring interval can significantly reduce the tensile deformation of concrete and alleviate stress concentration. This study confirms that the alternative bay method can effectively reduce the risk of temperature-induced cracking in ultra-long floor slabs and provide technical reference for seamless construction of similar above-ground structures. Full article

The urban–rural gradient of surface ozone concentration is closely associated with urban scale and has been widely reported in megacities globally. However, in the Sichuan Basin of southwestern China, a paradoxical asymmetric pattern between the ozone gradient and the physical urban footprint has emerged. By integrating multi-source satellite observations (e.g., TROPOMI), reanalysis data (ERA5-Land), and a concentric-ring spatial gradient analysis, we quantify a dipole-like urban surface ozone trap pattern in two megacities (Chengdu and Chongqing) from 2013 to 2019. We found that the urban–rural ozone gradients in Chongqing were substantially steeper than those in Chengdu, despite Chongqing’s smaller physical urban footprint. Specifically, in winter, the maximum daily average 8 h ozone level in the urban core drops to 27.5 μg m⁻³ in Chongqing and 47.9 μg m⁻³ in Chengdu, with outward radial increasing rates of 6.49% and 1.88% per 10 km, respectively. Conversely, the absolute nitrogen dioxide level in Chengdu is higher, highlighting an asymmetric titration behavior between the two cities. Regarding the chemical regime, analysis of the ratio (β) of nitrogen dioxide to formaldehyde reveals that Chongqing’s core operates under a more severe VOC-limited environment (β is 2.53 and radial gradient is −6.77% per 10 km) compared to Chengdu (β is 2.43 and gradient is −5.34% per 10 km). Furthermore, vertical cross-section analyses indicate that Chongqing’s deep-valley topography induces severe boundary layer compression and aerodynamic stagnation. Thus, rather than acting independently, these localized meteorological constraints function as crucial physical modulators that trap precursor emissions and exacerbate the non-linear chemical titration. This study elucidates how synergistic interactions between basin topography, physical urban footprints, and atmospheric chemistry shape localized ozone traps, providing a referable perspective for assessing complex urban atmospheric environments. Full article