Search Results (41)

Although measurements of urban shrinkage in China have received much attention, most have relied on statistical yearbook data based on political–administrative city boundaries, and remote-sensing-based quantification is mainly one-dimensional. This has caused problems in incorporating rural areas and spatiotemporal inconsistencies, as well as an inadequate understanding, which has subsequently resulted in an inaccurate shrinkage identification. This study merely utilized the latest multisensory and time-series remote sensing data, including nighttime light, land use, and population grids, to quantify the spatiotemporal patterns of multidimensional shrinkage based on the county-level urban entity mapping of Yangtze River Delta urban agglomerations (YRD-UAs) from 2003 to 2023. County-level urban entities were acquired from a pioneering mapping effort that utilized city-specific commuting distance and land use maps. The results demonstrated that urban entities in 215 counties grew at a generally slowing pace. The degree of economic, population, and space shrinkage was mainly slight, and the shrinking trajectory was dominated by temporary shrinkage. Most counties experienced population shrinkage in their coastal-oriented distribution, whereas economic shrinkage affected the fewest counties, with the lowest spatial clustering occurring northward. Population shrinkage also displayed the highest spatial autocorrelation, but its agglomeration weakened against space shrinkage clustering. This study concluded that the exclusive utilization of remote sensing products to measure urban-entity-based multidimensional shrinkage reduced the uncertainty associated with rural area inclusion and resulted in satisfactory assessment accuracy. The spatiotemporal patterns of multidimensional shrinkage suggested strengthening ecological land allocation within urban entities across the entire region, implementing polycentric development strategies in the north, as well as enhancing county-level economic governance in the northwest. This study presents a spatiotemporally comparable methodology for quantifying the multidimensional shrinking of county-level urban entities at a large scale and contributes to further optimizing the developments of YRD-UAs. Full article

The rural population shrinkage caused by China’s imbalanced regional development poses challenges to infrastructure configuration and operation. Traditional centralized sewage treatment models face issues in cost-effectiveness, facility utilization rates, and sustainable maintenance, necessitating the exploration of adaptive governance technologies under new demographic conditions. The utilization-driven governance approach is recognized as an emerging method for rural domestic sewage management. This study selects Heyang County, a representative agricultural area in Guanzhong Plain, as a case study. Through mixed-methods research integrating qualitative and quantitative approaches, we analyze the correlation between the Population Shrinkage Index (PSI) and facility operational efficiency, investigate the impact of resident population dynamics on rural sewage treatment patterns, and establish a theoretical “Source–Transmission–Sink” framework. Synthesizing local traditional governance practices with modern technological solutions, we propose a resource-oriented treatment system adapted to population shrinkage trends, comprising three technical components: source process reduction, transmission process interception, and sink process attenuation. This research emphasizes adjusting green water infrastructure (GWI) spatial configurations according to village characteristics in production–living–ecological spaces, forming a hierarchical attenuation mechanism through circular transmission pathways. This facilitates the transition from gray-infrastructure-dependent models to holistic pollution control systems with resource recovery capabilities. The findings provide theoretical foundations for policymaking and infrastructure planning in rural sewage management, offering significant references for sustainable rural water resource governance. Full article

Background: Diet plays an important role in preventing and managing the progression from prediabetes to type 2 diabetes mellitus (T2DM). This study aims to develop prediction models incorporating specific dietary indicators and explore the performance in T2DM patients and non-T2DM patients. Methods: This retrospective study was conducted on 2215 patients from the Henan Rural Cohort. The key variables were selected using univariate analysis and the least absolute shrinkage and selection operator (LASSO). Multiple predictive models were constructed separately based on dietary and clinical factors. The performance of different models was compared and the impact of integrating dietary factors on prediction accuracy was evaluated. Receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the predictive performance. Meanwhile, group and spatial validation sets were used to further assess the models. SHapley Additive exPlanations (SHAP) analysis was applied to identify key factors influencing the progression of T2DM. Results: Nine dietary indicators were quantitatively collected through standardized questionnaires to construct dietary models. The extreme gradient boosting (XGBoost) model outperformed the other three models in T2DM prediction. The area under the curve (AUC) and F1 score of the dietary model in the validation cohort were 0.929 [95% confidence interval (CI) 0.916–0.942] and 0.865 (95%CI 0.845–0.884), respectively. Both were higher than the traditional model (AUC and F1 score were 0.854 and 0.779, respectively, p < 0.001). SHAP analysis showed that fasting plasma glucose, eggs, whole grains, income level, red meat, nuts, high-density lipoprotein cholesterol, and age were key predictors of the progression. Additionally, the calibration curves displayed a favorable agreement between the dietary model and actual observations. DCA revealed that employing the XGBoost model to predict the risk of T2DM occurrence would be advantageous if the threshold were beyond 9%. Conclusions: The XGBoost model constructed by dietary indicators has shown good performance in predicting T2DM. Emphasizing the role of diet is crucial in personalized patient care and management. Full article

Background: While current epidemiological studies have documented associations between environmental metals and renal dysfunction, the majority have concentrated on plasma metal levels. The relationship between urinary metal exposure and chronic kidney disease (CKD) remains contentious, particularly within specific demographic groups. Methods: This cross-sectional study included 2919 rural Chinese adults recruited between 2018 and 2019. Urine metals were measured by ICP-MS. Least absolute shrinkage and selection operator (LASSO) regression was employed to identify metals significantly associated with CKD. Then, we used binary logistic regression, along with restricted cubic spline (RCS) models, to assess the individual exposure effects of specific metals on CKD. Quantile g-computation, weighted quantile sum regression, and Bayesian kernel machine regression (BKMR) models were applied to evaluate combined effects of metal exposures on CKD. Gender-stratified analyses were also conducted to explore these associations. Results: LASSO identified seven metals (V, Cu, Rb, Sr, Ba, W, Pb) with significant impacts on CKD. In single-metal models, Cu and W exhibited a positive correlation with CKD, whereas V, Rb, Sr, Ba, and Pb showed significant negative correlations (all p < 0.05). RCS analysis revealed nonlinear associations between V, Cu, Ba, Pb, and CKD (all p-nonlinear < 0.05). In the multi-metal model, quantile-based g-computation demonstrated a collective negative association with CKD risk for the seven mixed urinary metal exposures (OR (95% CI) = −0.430 (−0.656, −0.204); p < 0.001), with V, Rb, Sr, Ba, and Pb contributing to this effect. The WQS model analysis further confirmed this joint negative association (OR (95% CI): −0.885 (−1.083, −0.899); p < 0.001), with V as the main contributor. BKMR model analysis indicated an overall negative impact of the metal mixture on CKD risk. Interactions may exist between V and Cu, as well as Cu and Sr and Pb. The female subgroup in the BKMR model demonstrated consistency with the overall association. Conclusions: Our study findings demonstrate a negative association between the urinary metal mixture and CKD risk, particularly notable in females. Joint exposure to multiple urinary metals may involve synergistic or antagonistic interactions influencing renal function. Further research is needed to validate these observations and elucidate underlying mechanisms. Full article

Revealing the level of cultivated land use efficiency and its influencing factors in the northern agro-pastoral ecotone from the perspective of population contraction can provide a decision-making reference for ensuring national food security and promoting the implementation of rural revitalization strategies. In this paper, using the stochastic frontier production function and a Tobit regression model, we reveal the current situation of rural population shrinkage in the agro-pastoral ecotone in northern China and the spatial and temporal evolution characteristics of cultivated land use efficiency, and identify influencing factors based on the perspective of “human–land”. The results show the following: (1) The rural population in all provinces and counties in the agro-pastoral ecotone in northern China showed a continuous loss trend. The southwest was a hot spot area for rural population reduction, and the northeast was a cold spot area for rural population reduction. (2) During 2000–2020, the cultivated land use efficiency in the agro-pastoral ecotone in northern China showed a fluctuating upward trend, rising from 0.595 in 2000 to 0.754 in 2020. Spatially, the cultivated land use efficiency in the agro-pastoral ecotone in northern China showed the characteristic of being higher in the northeast and lower in the southwest, and the cultivated land use efficiency in some counties in the central and southwestern parts showed a downward trend. (3) The cultivated land use efficiency in the agro-pastoral ecotone in northern China is comprehensively affected by multiple factors. The following factors were determined, presented in descending order of the absolute value of influence degree: proportion of the population over 65 years old > multiple cropping index > proportion of cultivated land area > proportion of rural population > average years of education > population change rate. Based on these results, this paper puts forward measures to improve cultivated land use efficiency in the agro-pastoral ecotone in northern China from the perspective of population shrinkage, so as to provide references for ensuring national food security and promoting rural revitalization. Full article

Under the context of urban–rural mobility driven by rapid urbanization, rural shrinkage is particularly pronounced in the developed regions of China, yet studies exploring its patterns and influencing factors are scarce. This paper uses Zhejiang Province as a case study to investigate the spatiotemporal evolution and influencing factors of rural shrinkage from 2000 to 2020. By employing spatial autocorrelation analysis and spatial econometric modeling, the study investigates both population and spatial shrinkage. The findings reveal the following: (1) a marked spatiotemporal imbalance exists in population and spatial dynamics in Zhejiang’s rural areas, where the interplay between population and spatial shrinkage contributes to regional disparities. (2) From 2000 to 2020, population shrinkage shifted from a global shrinkage to a more localized decline in the northeast and southwest, while spatial shrinkage shifted from a global non-shrinkage to a focus on central and southwestern areas. (3) Urbanization significantly negatively impacts rural shrinkage, while the spatial spillover effect of urbanization is notably positive. In contrast, factors related to natural conditions, location, and agricultural investment show significant positive effects but also notable negative spatial spillover effects. This study aims to provide a comprehensive analytical framework for understanding rural shrinkage and offers valuable insights for rural development, infrastructure planning, and spatial governance. Full article

Traditional villages have reached milestones in developing a living culture, politics, economy, and society, among other aspects, while acting as important carriers of agricultural culture formed by long-term interactions between humans and nature. Unfortunately, traditional villages could disappear with the advent of urbanization. Therefore, this study enhances the accuracy of traditional village classification protection work by examining traditional villages in the Jinjiang River Basin in Quanzhou, China. A spatial pattern is extracted for the socio-ecological systems (SES) prototype of traditional villages, and an SES classification protection system is constructed based on a prototype analysis. Given the evaluation results, a K-means cluster analysis is applied to establish the SES sustainability levels for six types of traditional villages. After adjusting the types according to the principles of sustainability, equilibrium, and individual cases, six SES system types are identified: SES decay and shrinkage (Type 1), SES fusion and development (Type 2), SES ecological decline (Type 3), SES social decline (Type 4), SES ecological conservation (Type 5), and SES extensive development (Type 6). This system provides a quantitative analysis method to classify and protect concentrated and contiguous traditional villages. It also helps facilitate a better understanding of local rural society, economy, and culture, especially a deeper understanding of the interactions between humans and the rural environment. Full article

Nowadays, the reorganization of rural land-use space exhibits a dynamic process of expansion and shrinkage. Taking the Wuhan Metropolitan Area as an example, this study used the InVEST model to quantitatively assess changes in rural built-up land between 1995 and 2020 and its impact on regional carbon storage. Combined with the PLUS model, further simulations were carried out to predict the heterogeneous mechanisms of shrinkage and expansion of rural habitable space under three scenarios in 2030. The results indicate that the area of rural built-up land in the Wuhan Metropolitan Area showed an overall increasing trend, with shrinkage mainly concentrated in the Wuhan-Ezhou border, Tianmen, and southern Xiantao, while expansion displayed a decentralized point distribution. The PLUS model predicts that, in the scenario of rural built-up land expansion, a significant amount of cropland is encroached upon. This study provides a new perspective for understanding the impact of rural habitat changes on the carbon cycle. Future land management and planning should pay more attention to maintaining ecosystem services and considering the environmental effects of changes in rural built-up land layout. Full article

The rapid urbanization process has brought about the shrinkage of rural space as a typical issue. Nevertheless, due to the dearth of effective assessment approaches, the patterns of rural spatial shrinkage remain poorly grasped. This study intends to establish a quantitative assessment model to scientifically disclose the spatiotemporal characteristics and mechanisms of rural spatial shrinkage. The “Population-Industry-Function-Land” (PIFL) assessment model has been rigorously constructed, encompassing eight assessment indices, such as the ratio of permanent residents, rural population density, and the rate of abandoned cultivated land. The model was adopted to conduct an analysis of the spatial shrinkage scenarios of the 18 administrative villages in Panxi Town spanning from 2011 to 2021. The results indicate that the temporal dimension of rural spatial shrinkage exhibits an accelerating trend, with discernible declines or increases in the ratio of permanent residents, rate of the elderly labor force, and housing vacancy rate. The shrinkage of rural spaces displays spatial heterogeneity, with more pronounced shrinkage characteristics observed in villages located further from the central town. According to the comprehensive shrinkage index, the villages are categorized into four types: relative shrinkage (0.2447 ≤ Z ≤ 0.2462), mild shrinkage (0.2463 ≤ Z ≤ 0.4423), moderate shrinkage (0.4424 ≤ Z ≤ 0.6125), and severe shrinkage (0.6126 ≤ Z ≤ 0.7988). The research findings possess significant reference value for the governance of rural spatial shrinkage. Full article

One current global problem is the shrinkage of rural areas, which is expected to become an increasingly recurrent dynamic caused by the transformations in land uses and forms of habitation of the contemporary era. Patagonia is a suitable case study to understand the processes and challenges exposed by rural shrinkage, which not only addresses population loss but also the causes and consequences that transform rural territories. Its remote geographical location and climate conditions make it a complex place for human settlement. The objective is to describe the relationship between the agrarian structure and rural population decline in Chilean Patagonia. Taking a mixed methodological approach that combines the geohistorical review of settlement processes and the use of statistical procedures with census data, the presence of significant inequalities in the distribution of land and the accumulation of areas in large properties is discussed. The loss of rural population was identified, which may be driven by unequal access to land favoring concentration for extractive activities such as large-scale sheep farming, hydrocarbons and biofuels production. This prompts the exodus of young people to urban centers in search of work and education because land grabbing limits economic options, and rural depopulation reduces service coverage without timely responses from political institutions. This has caused the rural shrinkage in territories with demographic imbalances, with high aging and masculinization rates that hinder the repopulation of these areas, which have historically suffered from underpopulation. In conclusion, population strategies in these areas based on extractivism and a strict land ownership regime have not facilitated permanent human settlement but have instead complicated it more. Full article

Improving local identity is the key to rural sustainable development. Facing the issue of rural hollowing and aging, rural human settlement requires targeted enhancement in conjunction with the living willingness and local identity of villagers. Firstly, this study summarizes the dynamic evolution characteristics of rural human settlement development and population contraction in Yunnan Province from 2001 to 2021, based on the “Production-Living-Ecological” theory. Secondly, the paper selects detailed survey data from 40 administrative villages in Yunnan Province in 2015, analyzes the characteristics of villagers’ living visions in typical villages through questionnaire data, and constructs a comprehensive local identity index model based on multilevel living-visions to quantify the degree of villagers’ identification with rural human settlement construction. Thirdly, the paper analyzes the correlation between the local identity index and the comprehensive human settlement evaluation and analyzes the factors of rural human settlement development that affect the local identity in depth. The results reveal that: (1) rural construction in Yunnan Province cannot adapt to the changing needs of villagers, and the development of rural human settlement is accompanied by a trend of relative shrinkage of the rural population. (2) The local identity index of villagers is weakly correlated with the development of rural human settlements. (3) The rural human settlement factors that influence rural local identity include a dual cohesion–centrifugal trend. The findings suggest that rural development depends on the primary and secondary relationship between cohesion and centrifugal trends, providing a reference for the coupling of rural construction and local identity and promoting the return of rural population to achieve sustainable development. Full article

Prenatal malnutrition may increase the risk of depressive symptoms in adulthood. This study investigated the association between prenatal exposure to malnutrition with risk of depressive symptoms in middle-aged and older adults using the Chinese Great Famine of 1959–1961 as a natural experiment. Data were obtained from the China Health and Retirement Longitudinal Study baseline survey (2011). A total of 5391 individuals born from 1956 to 1965 were included in the study. Depressive symptoms were ascertained via the Center for Epidemiological Studies Depression Scale short form. Famine severity was measured using the cohort size shrinkage index. Difference-in-differences models were used to explore the association between prenatal famine exposure and later-life depressive symptoms. Compared with the post-famine cohort (1963–1965), famine cohorts (1959–1962) were 4.74 times (95% CI = 1.28–8.20) as likely to develop depressive symptoms. The stratified analysis found that prenatal exposure to famine was associated with depressive symptoms in rural residents but not those living in urban areas. In rural females, prenatal malnutrition was associated with a higher risk of depressive symptoms. However, there was no significant association between prenatal malnutrition and depressive symptoms in rural males. Our results indicated that prenatal malnutrition may contribute to a higher risk for depressive symptoms in later life among female rural residents. Full article

Population shrinkage has had a certain negative impact on urban and rural development in many aspects. The impact of population shrinkage on urban–rural integration has become one of the core scientific issues that needs to be addressed in the current research on promoting the goal of common prosperity in China. Northeast China is a typical region in China that is experiencing a decrease in population and economic activity. Investigating the integrated development of urban and rural areas in this region is highly important for revitalizing Northeast China. This research paper focuses on 32 prefecture-level cities in Northeast China and utilizes spatial correlation analysis and the Geographical Weighted Regression model to uncover the evolving spatial patterns and influential factors affecting integrated urban–rural development in the context of population decline. The findings revealed the following: (1) The level of integrated urban–rural development in Northeast China continues to rise despite the shrinking population. During the comprehensive population decline stage, the growth rate of the urban–rural coupling coordination degree surpasses that of the initial stage. The areas with high values of urban–rural coupling coordination degree shift from northeastern Heilongjiang to four sub-provincial cities. The spatial correlation between urban–rural coupling and coordinated development weakens, with the main type being low–low agglomeration. (2) Factors such as economic development level, labor force size, urbanization level, level of openness, urban–rural accessibility, and proportion of built-up areas significantly correlate with urban–rural coupling and coordination. The influence of each factor varies in magnitude and direction across different locations. Labor force size and urban–rural accessibility have the most-significant impact on integrated urban–rural development, with labor force size having a positive effect and urban–rural accessibility having a negative effect. The impact of the economic development level follows a pattern of initial increase and subsequent decrease as the population shrinks. (3) Although population decline does not hinder integrated urban–rural development in Northeast China, it is closely connected to changes in the factors influencing such development. To capitalize on the development opportunities presented by national policies, Northeast China should adopt a model of urban–rural development that promotes rural growth through cities. This entails attracting talented individuals to return, enhancing the flow of urban–rural development elements in both directions, and creating a spatial development pattern characterized by “big city, big agriculture, and big ecosystem”. By doing so, the revitalization of Northeast China can be achieved. Full article

Soil is continuously excavated for development activities in urban and rural areas and treated as waste. This study investigates the characteristics of urban soils excavated from earthworks of buildings in the Brittany region of France for their perspective reuse in earthen construction materials to valorize soil waste and provide a sustainable building material locally. Excavated soil from earthwork activities was taken from the Brittany region of France from three different locations. Soil suitability for compressed earth blocks was investigated based on their granulometry, consistency limits, and mineralogy. Finally, compressed earth blocks with dimensions of 4 × 4 × 16 cm³ were manufactured with different formulations and compacted dynamically. Flexural and compressive strength tests were performed on bricks to observe their mechanical behavior. Grain size analysis of soil samples shows that the percentage of clay in the landfill stockpile of excavated soils varies between 13% and 16%, while at some local sites, the percentage of clay goes up to 57%. The grain size of soils varies from the recommended zone. The plasticity of soil samples ranges from 17.3% to 20.4%. The plasticity index and clay content of the soil show that these soils are inactive clays with a lesser possibility of swelling and shrinkage. Mineralogical analysis of soil shows the absence of water-sensitive clay minerals, while quartz, kaolinite, and illite are major minerals present in soils. Linear shrinkage in bricks ranges from 0.6% to 2.2% and is considerably higher for clayey soils. Mechanical testing of earth bricks shows that the compressive strength of earth blocks ranges from 0.92 MPa to 2.22 MPa while the flexural strength ranges from 0.25 to 0.74 MPa. A mixture of sandy and clayey soils shows good strength due to improved granulometry. Earth bricks with soils from some stockpiles, excavation sites, and soil mixture show compressive strength higher than 1 MPa, which is recommended strength by international standards, and offer the opportunity to produce sustainable building materials locally. Full article

Globally speaking, Asian countries, especially East Asian countries, are facing acute national depopulation situation and severe rural shrinkage development. Based on the continuous surveys of town and village development in Japan, South Korea, and China, this study aims to provide an overview of social policies that have been implemented in the past or more recently in these three countries in response to rural shrinkage, and to outline the core philosophy of these practices to cope with the repercussions. In this paper, we analyze the overall process of rural depopulation and the present features of town and village development in three countries. We subsequently present the social policies over the last few decades and summarize them into four major groups. Furthermore, we highlight that the focus of social policies is not to seek possible ways to reestablish growth but to provide positive support and effective reform to adjust and satisfy the changing needs of towns and villages under the circumstances of shrinking development, including the optimization of public resource allocation, exploring institutional innovation to valorize abandoned assets, and developing endogenous potentials for future sustainable development. Qualitative methods from a combination of literature review, policy review, and field surveys have mainly been adopted in this research. The study of East Asian practices may be instructive for other Asia-Pacific countries, as well as European countries that have been experiencing or will eventually face the challenges of rural shrinkage. Full article