Carrying Capacity Of Resources Research Articles

A Review on the Overall Optimization of Production–Living–Ecological Space: Theoretical Basis and Conceptual Framework

The 18th National Congress of the Communist Party of China put forward the optimization of territorial space development patterns as the primary measure of ecological civilization construction, and put forward the goal of “promoting intensive and efficient production space, livable and moderate living space, and beautiful (picturesque scenery) ecological space”. Through literature research and summing induction, this paper combs the research progress of the overall optimization of “Production–Living–Ecological” space (PLES) systematically. It is found that the existing work mainly focuses on the overall optimization of PLES from the perspectives of land-use quality, land-use suitability evaluation, resource and environmental carrying capacity, and comparative advantages. However, due to the lack of understanding of the scientific connotation of PLES, and the imperfect construction of quantitative identification methods and classification system, there are many problems in the technical approaches of the overall optimization of PLES, which remain to be clarified. In the future, the technological approach to the overall optimization of PLES should be guided by the vision of building a beautiful China, with the theory of a human–Earth coupling system as the core, and systematically build a theoretical system and technical framework to identify and optimize territorial space.

Identifying Spatial Matching between the Supply and Demand of Medical Resource and Accessing Carrying Capacity: A Case Study of Shenzhen, China.

Previous Studies, such as the evaluation of the supply of and demand for regional medical resources and carrying capacity assessments, require further development. This paper aims to evaluate the carrying capacity and spatial distribution of medical resources in Shenzhen from the perspective of supply and demand, and to conduct a time-series variation of the coupling coordination degree from 1986 to 2019. The two-step floating catchment area method was employed to quantify the carrying capacity and coupling coordination degree method and spatial autocorrelation analysis were applied to analyze spatial distribution between supply and demand. The results were as follows. (1) The carrying capacity index in more than 50% of the districts was classified as low-grade. The percentage of regions with good grades was 8.27%. The regions with a high carrying capacity were distributed in the central and southeastern areas. (2) The coupling coordination continued to rise, increasing from 0.03397 in 1986 to 0.33627 in 2019. (3) The level of supply and demand for medical resources in Shenzhen increased from 1986 to 2019, and the highest degree of compatibility between the supply and the population size was largely concentrated in the western and eastern regions. This research can provide a theoretical reference for Shenzhen to rationally plan medical resources and improve the carrying capacity of medical resources.

Evaluation of Rural Tourism Carrying Capacity Based on Ecological Footprint Model

The evaluation of the environmental carrying capacity of tourism resources has important guiding significance for the sustainable development of tourism. This study uses the ecological footprint index to construct the evaluation model of rural tourism environmental carrying capacity and quantitatively analyzes the impact of rural tourism ecological footprint on the environment, ecological pressure, and the maximum carrying capacity of tourists in Nanyang City (China) from 2011 to 2020, so as to provide a reference basis for local rural tourism planning and ecological environment management. The empirical analysis results show that (1) during the decade 2011–2020, the overall ecological footprint increased by 31.47%; however, the per capita ecological footprint showed a downward trend year by year; (2) in the ten years from 2011 to 2020, although the environmental carrying capacity was in surplus, it showed a downward trend year by year, and the ecological pressure index initially appeared; (3) taking the number of tourists in 2020 as the reference value, the prediction of the ecological pressure of rural tourism environment and the carrying capacity of tourists shows that although the ecological pressure is in a relatively safe state, it will show an unsafe state with the increase of the number of tourists. Based on the above results, it is suggested that local governments and tourism planning and management departments should pay full attention to the adverse impact of tourism development on the environment, strengthen the construction of green transportation, balance the development of tourism resources, scientifically control the number of tourists, improve tourists’ awareness of environmental protection, protect the ecological environment of Nanyang City, and realize the sustainable development of rural tourism.

Evaluation of the Water Resource Carrying Capacity on the North Slope of the Tianshan Mountains, Northwest China

Water resource carrying capacity (WRCC) is essential for characterizing the harmony between humans and water resources in an area. Investigation of the WRCC is useful for guiding the sustainable development of a region. The northern slope of the Tianshan Mountains is an important area for the economic development of Xinjiang, China. In recent years, the supply of water in the area barely satisfies the demand. To quantitatively evaluate the WRCC, data for four indicators including the water resources, social and economic development, and ecological environment of the area were utilized. The comprehensive weighting method, which combines the entropy and analytic hierarchy processes, was used to assess these indicators. A fuzzy comprehensive evaluation model was employed to evaluate the urban WRCC of the northern slope of the Tianshan Mountain for 2018. The results showed urban WRCC values varying between good and moderate for the northern slope of the Tianshan Mountains, and this indicates that the study area is in a loadable state. Although the water supply can meet the development of cities on the northern slope of the Tianshan Mountains to a certain extent at this stage, because it is located in the arid region of western China, the shortage and uneven distribution of water resources are one of the biggest limiting factors for the future development of this region. The findings of the present study provide a basis for the development, rational allocation, and sustainable utilization of urban water resources on the northern slope of the Tianshan Mountains.

Evaluating and simulating resource and environmental carrying capacity in arid and semiarid regions: A case study of Xinjiang, China

Resources and environment provide the fundamental conditions for human life. With the rapid growth of population and development of regional social economies, the environment and ecosystems have been disturbed to varying degrees. Contradictions among human beings, resources and environment have become a key issue restricting the sustainable development, particularly in arid and semiarid regions. This study takes the arid and semiarid region of Xinjiang, China, as an example. An evaluation model and index system of resource and environmental carrying capacity (RECC) are proposed based on the “pressure-vulnerability-adaptability” (PVA) concept. The RECCs in Xinjiang from 2000 to 2019 were quantitatively evaluated, and the reasons for the spatio-temporal changes of RECC were explored. In addition, the ordered weighted averaging (OWA) algorithm was introduced to realize multi-scenario simulations with concerning different decision-making preferences. Results indicated that: (1) the RECC in Xinjiang presents a spatial pattern of “high pressure around the three mountains and low pressure around the two basins” and the area of high carrying capacity decreased significantly from 2000 to 2019; (2) the pressure risk indicators are key factors in evaluating the RECC and the difference between the regional RECC and pressure risk is largely affected by vulnerability and adaptability; (3) the future regional RECC are predicted differently under different development orientations via the OWA algorithm, which is useful to provide decision-making references for promoting sustainable development.

Spatial Equilibrium Evaluation of Regional Water Resources Carrying Capacity Based on Dynamic Weight Method and Dagum Gini Coefficient

With the rapid economic development and the acceleration of urbanization, the pressure on the water resources system is becoming intense. As an important indicator of water resources security and sustainable development, the water resources carrying capacity has become a hot issue. To overcome the limitation of commonly used methods for weight determination and to evaluate the regional water resources carrying capacity reasonably, the index weight determined by the Analytic Hierarchy Process method was revised by the subtraction set pair potential to calculate the dynamic index weight. Then, the dynamic weight was combined with the set pair analysis method to evaluate the regional water resources carrying capacity dynamically. In addition, the Dagum Gini coefficient and its decomposition method were used to analyze the overall difference of water resources carrying capacity in the whole region and the differences within and between subregions considering the lack of quantitative research in spatial equilibrium. Finally, a case study was carried out in Anhui Province, China. The results showed that from 2011 to 2018, most of the water resources carrying capacity for 16 cities in Anhui Province were in a critical state, with the strongest in the south of Anhui Province and the weakest in the north. The overall spatial difference of carrying capacity in Anhui Province showed an increasing trend from 2011 to 2018. Furthermore, the slightest difference within the subregion was in the north of Anhui Province, while the largest was in the south. The most significant difference between the subregions was between the south and the north of Anhui Province. The primary source of carrying capacity spatial difference in Anhui Province was from the difference between subregions. The results of the case study suggested that the method proposed in this paper are conducive to the early find of possible disadvantages of spatial equilibrium and can effectively identify the main source of regional spatial difference in water resources carrying capacity, which means that the method can be widely applied to similar issues.

Retracted] Rough Set Construction and Entropy Weight Evaluation of Urban Higher Education Resource Carrying Capacity Based on Big Data

With the popularization of higher education, the scale of urban higher education continues to expand, and the contradiction between the supply and demand of educational resources becomes increasingly prominent, which restricts the steady development of urban higher education. Based on the rough set theory, this paper constructs a rough set of big data of urban higher education resource carrying capacity from the three levels of higher education core resources, urban economic resources and urban basic resources, and evaluates the entropy weight of the city where the university is located. According to the theoretical knowledge of higher education resource carrying capacity, the system deconstructs and expounds the balance mechanism of higher education resource carrying capacity, which provides solid theoretical support for the development of the paper. The research shows that the agglomeration development of higher education resources can improve the carrying capacity of urban higher education resources. The second section performed well on the whole, and the index distribution was more uniform. The third interval index structure distribution is complex and uneven, and the overall performance is general. The fourth section belongs to the poor section of educational carrying capacity with a low overall index. It can be seen that the carrying capacity of higher education resources varies significantly, which provides a scientific basis for improving the carrying capacity of higher education resources and theoretical and policy basis for realizing rational allocation and sustainable carrying capacity of higher education resources.

Spatial Differentiation and Influencing Factors of the Green Development of Cities along the Yellow River Basin

The traditional development model of high consumption and low efficiency approaches the threshold of resource and environmental carrying capacity, bringing a series of severe social and ecological environmental problems, and it is urgent to realize green development transformation. Based on a multidimensional perspective, this paper constructed a comprehensive evaluation system for urban green development along the Yellow River Basin (YRB). Entropy method, exploratory spatial data analysis (ESDA) model, and trend analysis were used to measure and characterize the spatiotemporal evolution of urban green development index (UGDI) along the YRB in 2008, 2013, and 2018, and geographically weighted regression (GWR) model was used to explore the influencing factors of urban green development. The results are as follows: (1) the UGDI along the YRB showed a slow upward trend, but the absolute value was relatively low, mainly concentrated in 0.2699–0.3799. (2) The UGDI had obvious regional differences, and cities such as Baotou and Zibo showed a “high‐high” agglomeration, while most cities in the midstream showed a “low‐low” agglomeration, and in terms of space, they were “high in the east and west, low in the middle” and “high in the north and low in the south.” (3) Influencing factors had different degrees of impact on the UGDI. Economic, industrial, urbanization, and green infrastructure factors played a positive role in promoting the urban green development, while the relationship between governance, technological factors, and green development varies from city to city.

Resource and environmental carrying capacity in China for 35 years: Evolution, hotspots, future trend

Resource and environmental carrying capacity in China for 35 years: Evolution, hotspots, future trend

Study on the path of Xi Jinping's ecological view for the high quality development of islands

PurposeThe island areas, in particular, are characterized by a more fragile ecological carrying capacity and higher value of resources and environment, which requires us to take Xi Jinping's green ecological development view as the theoretical basis and adhere to the high-quality development path of gradual development and ecological environment priority. Taking Shengsi and Daishan counties as examples, on the basis of their high-quality development evaluation and identification of the main influencing factors, this study explores the specific path of Xi Jinping's ecological development view in the high-quality development of typical island counties in China.Design/methodology/approachThis paper applies the interpretative structural model to construct an evaluation index system for the high-quality development of the island. In determining the factor weights of the index layer, the AHP hierarchical analysis method was combined with the Delphi method to increase the objectivity of the assignment process as much as possible. This study used the technique for order of preference by similarity to ideal solution to calculate island high quality development index. To measure the main obstacle factors, the index factor contribution rate, the index factor deviation, and the index factor obstacle degree were applied in this research.FindingsThe study is supported by Guangxi Key Laboratory of Marine Environmental Science, Guangxi Academy of Sciences (GXKLHY21-04), Special Funds for Fundamental Scientific Research Operation of Central Universities (202113011), Shandong Provincial Social Science Planning Research Youth Project (21DSHJ2) and Tianjin Philosophy and Social Science Planning Project of China (No. TJKS20XSX-015).Originality/valueThe connotation and extension of Xi Jinping's view of ecological development should be continuously studied in depth and enriched, with green development as the core idea to guide the correct direction of the high-quality development of the island. In this paper, it is suggested that researchers are supposed to focus on these problems, such as the changes of sea water quality, the reduction of urban greening, the continuous negative growth of population in island areas, the decline of forestry added value and air quality protection, so as to ensure the sustainable high-quality development of example islands.

Analysis and Prediction of Land Resources’ Carrying Capacity in 31 Provinces of China from 2008 to 2016

The rapid development of urbanization, population growth, and unreasonable use of land resources have made the contradiction between human beings and land increasingly prominent, and the carrying capacity of land resources has become an important factor affecting the sustainable development of a city or even a country. Based on the carrying capacity of agricultural land, construction land, and ecological land in 31 provinces of China, this paper analyzed the spatiotemporal characteristics of the carrying capacity of land resources in 31 provinces of China from 2008 to 2016 by using single-factor carrying capacity evaluation and comprehensive carrying capacity evaluation methods. The evaluation results were divided into six levels (No pressure, Lower pressure, Low pressure, Medium pressure, High pressure, Higher pressure), and the ArcGIS10.2 software was used for visualization, and the carrying capacity prediction model was constructed to predict the development trend of the comprehensive carrying capacity of land resources in 2020 and 2025. The results showed that China’s land carrying capacity is extremely unbalanced. Whether from the evaluation results of single-factor carrying capacity or comprehensive carrying capacity, we showed the characteristics of high pressure in the east and low pressure in the west, and that the regional land resources have a deteriorating trend. Through the prediction of the future land resource carrying capacity index, it was found that the comprehensive carrying capacity index of land resources in 31 provinces of China will still show an upward trend in the future.

Integrated Evaluations of Resource and Environment Carrying Capacity of the Huaihe River Ecological and Economic Belt in China

The evaluations of resource and environment carrying capacity and territorial development suitability, also referred to as “double evaluations”, have been taken by China as an important direction in territorial space planning. Based on the evaluation of resource and environment carrying capacity, the double evaluations can contribute to protecting ecological safety and territorial safety and promoting regional sustainable development. The focus of this study was to integratedly evaluate the resource and environment carrying capacity of the Huaihe River Ecological and Economic Belt. First, the overall weights of the factors at the dimension level and the index level in the established integration evaluation system were calculated with the fuzzy analytical hierarchy process (FAHP) method; and then, using the linear weighted function, the overall resource and environment carrying capacities of 25 cities in the belt were calculated. On that basis, the resource and environment carrying capacity evaluation model was established. Through model analysis, this study comprehensively investigated the resource and environment carrying capacity of the Huaihe River Eco-economic Belt and provided a foundation for the future territorial space planning and layout of the Huaihe River Eco-economic Belt.

Improving integrated environmental zoning from the perspective of logic scoring of preference and comparative advantage: A case study of Liangjiang New Area, China

Rapid industrialization and urbanization have caused serious conflict between humans and nature due to the spatial variability of natural environmental conditions. Integrated environmental zoning (IEZ) is an efficient tool to regulate sustainable development in developing countries such as China. Previous studies explore application of IEZ based on assessment of resource and environmental carrying capacity (RECC) and evaluation of urban development land-use suitability (UDLS). However, existing IEZ oversimplify the complexity of UDLS evaluation, and have low spatial resolution. In addition, it is difficult to express overlay results of RECC and UDLS from a multi-dimensional perspective. Therefore, this study sets forth an improved IEZ by a logic scoring of preference (LSP) and a comparative advantage evaluation. The LSP method and normalized revealed comparative advantage (NRCA) index is applied to assess UDLS and the comparative advantage of RECC (CARECC). The results of IEZ are integrated by overlaying the CARECC zones with numerically processed UDLS maps. A small-scale, rapid development area, Liangjiang New Area (LJNA), serves as the study area. The highly suitable, suitable, moderately suitable, marginally suitable, and not suitable land of LJNA covers 276.60, 368.40, 183.45, 143.22, and 228.33 km2, respectively. Furthermore, the spatial distribution of RECC in LJNA clearly differ. Based on the results of UDLS and RECC, ten types of integrated environmental zones in the form of “category + intensity” are delineated. The improved IEZ is consistent with the LJNA Master Plan, reflects the logic of human reasoning more accurately, increases the spatial resolution, achieves zoning from multi-dimensional perspectives, restricts the category and determines the sequence of urban development, which can serve as a reference for optimization of land space in LJNA and is also significant to other areas and places.

Resource and Environmental Carrying Capability Assessment of Underground Space in Yuzhong Peninsula in Chongqing

The rational development of urban underground space resources has attracted much attention as an important measure to deal with the urban population, resource, and environmental crises. Resource and environmental carrying capability (RECC) is a key parameter to measure the sustainable development of underground spaces, which is very important for the sustainable development of regional economy and environment. Considering the scarcity, irreversibility, and geological constraints of urban underground spaces, the assessment analysis model and assessment index system were determined according to the actual conditions of Yuzhong Peninsula in Chongqing. The assessment index system comprises the socioeconomic development, resource-carrying capacity, and environmental vulnerability. The resource-carrying capability has a positive effect on the assessment result, while socioeconomic development and environmental vulnerability have a limiting effect. According to urban planning policies and utilization experience, the underground space was divided into three assessment layers, namely, a shallow layer (0– 10 m underground), subshallow layer (10–30 m underground), and deep layer (30–100 m underground). The remaining exploitable capacity of the underground space and RECC of the shallow, subshallow, and deep layers in Yuzhong Peninsula were calculated using a self-developed assessment system.

Assessment of Water Resources Pollution Carrying Capacity in The Sa Kaeo Special Economic Zone, Thailand

The Phromhot Canal is the only natural water source for consumption and agriculture the Sa Kaeo special economic zone, Thailand. At present, the Phromhot Canal is facing a serious problem with water quality. Our study carried out to analyze and assess the pollution carrying capacity of the natural water resource. The sampling sites were examined 7 stations cut across the downstream areas. All these stations were served as the control station to represent the actual condition of the Phromhot Canal. The results indicated that the water quality of the Phromhot Canal after flowing through the Aranyaprathet Municipality's wastewater treatment plant (AM's-WWTP) was severely contaminated. Effluents from the AM's-WWTP does not meet the effluent quality standard of the Ministry of Natural Resources and Environment, Thailand. In addition, it can flow into the water body up to 6,439.55 m3/day. The maximum amount of a pollutant (in terms of BOD loading) allowed to enter a water body of the Phromhot Canal should be ≤ 0.08 kgBOD/day (dry period) and 16.52 kgBOD/day (wet period). While the Phromhot Canal has to carry BOD loading up to 51.12 kgBOD/day. For this reason, the Phromhot Canal at after flowing through the WWTP was unable to the pollution carrying capacity. From the field survey, the AM's-WWTP is not suitable for wastewater treatment, which has a capacity of 923.93 m3/day. Therefore, it is necessary to strictly control the drainage of the wastewater from the Aranyaprathet Municipality's wastewater treatment system, both quantitative and geographic.

Daya Dukung Sumberdaya Air dan Indeks Kekritisan Air Sub DAS Cisokan Hulu

Upper Cisokan sub-watershed is a natural ecosystem of water resource providers that can be used directly or indirectly by the community in it. The population rate and sectoral needs in a sub-watershed area are estimated have put pressure to the water resources balance. The value of the carrying capacity and the water criticality index in the existing condition and its projections for the next 10 years are known from the water balance analysis. The availability of water resources (Wn) was determined based on the flow rate probability (Q80) of Weibull Method, the value of groundwater estimation, springs and wells, and also the raw water supply of local water company. Water demand (qpt) was estimated based on Statistic data of Upper Cisokan sub-Watershed 2020 and the projection for 2030, industrial data, agricultural area data, livestock production data, and fishery area data. The water resources carrying capacity (Cw) of the Upper Cisokan sub-watershed is generally still adequate (High), but at the peak of the dry season, namely June to November, the water carrying capacity status shows a value of 1.84 (Critical) to 0.24 (Deficit). In general, the water criticality index is still safe (Not Critical), but in the dry period, especially in July, August and November, it shows a value of 125% to 421% (Very Critical). To anticipate the water crisis, all stakeholders should allocate water efficiently according to its availability. So that the sub-watershed ecosystem is sustainably provide ecosystem services for providing water resources to the community. Key words: Ecosystem Services, Water Supply, Water Demand, Water Balance, Water Resources Carrying Capacity, Water Criticality Index, Upper Cisokan Sub Watershed

Impact of Urbanization on the Environmental Regulation Efficiency in the Yangtze River Basin Based on the Empirical Analysis of Spatial Econometrics.

Urbanization has been positioned as an important driving force for economic development. This article examines the impact of urbanization on environmental regulation efficiency (ERE) in the Yangtze River Basin (YRB). Based on a panel dataset of 97 cities in the YRB from 2005 to 2016, a spatial econometric model was used for analysis. Results show that the average ERE in the YRB is relatively low and manifests in the shape of a curved smile. The urbanization level of the permanent population is far lower than the average level of developed countries. However, the urbanization level is showing a steady growth trend. During this period, ERE in the Yangtze River middle, upper, and lower reaches was measured at 0.77, 0.58, and 0.52, respectively. The urbanization rate was measured at 0.59, 0.45, and 0.39, in the lower, middle, and upper reaches, respectively. When only considering population urbanization, the previously observed negative correlation between ERE and the Kuznets curve disappears. However, if the carrying capacity of economic activities is considered, the U-shaped relationship between urbanization rate and ERE returns. The environmental Kuznets curve is consequently verified. In addition, there is an inverted U-shaped nonlinear relationship between economic development and ERE. The results of this article show that there are unsustainable risks in the rapid pursuit of population urbanization. Only by improving the quality of urbanization and adapting the level of urbanization to the carrying capacity of resources and environment can we truly promote high-quality economic development. The article puts forward some suggestions to promote the green development of the economy.

Assessment of water stress level about global glacier-covered arid areas: A case study in the Shule River Basin, northwestern China

Study regionThe Shule River Basin (SRB) in northwestern China is a representative area of global glacier-covered arid areas. Study focusWater resources have greatly influenced sustainable development in global arid regions where glacier runoff is an important component of water resource supply. This study focused on the assessment of the water resources–carrying capacity in the SRB based on the United Nations Sustainable Development Goals (SDGs) indicator 6.4.2, level of water stress (LWS). New hydrological insights for the regionDuring the period between 2000 and 2030, the runoff of the SRB was predicted to follow an overall increasing trend. From 2000 to 2020, the annual average runoff in the upper reaches of the SRB was 10.9 × 108 m3, and then from 2021 to 2030, it increased by 22.8 %. According this trend, the average contribution of glacier meltwater to the total basin runoff is expected to decrease from the current 23 % to 15 % by 2030 (Representative Concentration Pathway 2.6, RCP 2.6). The supply of fresh-water resources has been close to the level of demand since 2015 and the LWS may increase between 2021 and 2030. The existence of glacial meltwater is expected to result in the continued reduction of basin water stress in the SRB by an average of 0.71 during the period between 2000 and 2030. Therefore, it is necessary to control water consumption of the socioeconomic system and adjust the industrial structure to face or adapt to the crisis of water shortage in global glacier-covered arid areas.

Temporal and spatial evolution and obstacle diagnosis of resource and environment carrying capacity in the Loess Plateau.

Natural resources are scarce in the Loess Plateau, and the ecological environment is fragile. Sustainable development requires special attention to resource and environmental carrying capacity (RECC). This study selected 24 representative cities in five natural areas of the Loess Plateau; used the entropy-weight-based TOPSIS method to evaluate and analyze the RECC of each city and region from 2013 to 2018; established a diagnosis model to identify the obstacle factors restricting the improvement of RECC; and constructed the theoretical framework of the RECC system mechanism. The results show that the RECC of the Loess Plateau is increasing in general but is relatively small. The environmental and social subsystems have the highest and lowest carrying capacities, respectively. There is an evident contradiction between economic development and the environment. Population density, investment in technological innovation, per capita sown area, and per capita water resources are the main obstacles affecting the improvement of RECC in the Loess Plateau. Such evaluations and diagnoses can support ecological civilization and sustainable development.

ESTIMATION OF POTENTIAL WATER AVAILABILITY AND WATER RESOURCES CARRYING CAPACITY FOR BOGOR CITY SPATIAL PLAN

The aim of the present research is to examine the effectiveness of rational method widely used in calculating water availability for spatial planning in Indonesia. The rational method is developed mainly for estimating the characteristics of drainage infrastructure instead of estimating water availability. The effectiveness of rational method and Soil-Conservation Service Curve Number (SCS-CN) method are compared by testing their performance in estimating water availability in the Upper Cisadane river basin in West Java, Indonesia. The results shows that calibrated SCS-CN model performs better than Rational model with R2 and NSE of 0,62 and 0,37. Result of model validation yields R2 = 0,73 and NSE = 0,52. The result suggests that SCS-CN performs better than the rational model in simulating the character of water catchment area and is suitable for model of choice in water availability estimation. Keywords : Bogor City, Regional Spatial Planning, Water availability, Water Balance, Water Resource Carrying Capacity