Distribution,characteristics and influencing factors of fresh groundwater resources in the Loess Plateau,China

The fresh groundwater in the Loess Plateau serves as a major source of water required for the production and livelihood of local residents and is greatly significant for regional economic and social development and ecological protection. This paper analyzes the hydrogeological conditions and groundwater characteristics in the Loess Plateau, expatiates on the types and distribution characteristics of the fresh groundwater in the plateau, and analyzes the influencing factors and mechanisms in the formation of the fresh groundwater in the plateau as a priority. Based on this, it summarizes the impacts of human activities and climatic change on the regional fresh groundwater. The groundwater in Loess Plateau features uneven temporal-spatial distribution, with the distribution space of the fresh groundwater closely relating to precipitation. The groundwater shows a distinct zoning pattern of hydrochemical types. It is fresh water in shallow parts and is salt water in deep parts overall, while the fresh water of exploration value is distributed only in a small range. The storage space and migration pathways of fresh groundwater in the loess area feature dual voids, vertical multilayers, variable structure, poor renewability, complex recharge processes, and distinct spatial differences. In general, the total dissolved solids (TDS) of the same type of groundwater tends to gradually increase from recharge areas to discharge areas. Conditions favorable for the formation of fresh groundwater in loess tablelands include the low content of soluble salts in strata, weak evaporation, and special hydrodynamic conditions. Owing to climate change and human activities, the resource quantity of regional fresh water tends to decrease overall, and the groundwater dynamic field and the recharge-discharge relationships between groundwater and surface water have changed in local areas. Human activities have a small impact on the water quality but slightly affect the water quantity of the groundwater in loess.© 2021 China Geology Editorial Office.     

Study on Retrieving Key Ecological Parameters in Mountainous Regions by Remote Sensing Methods and Evaluating Their Spatio-temporal Representativeness

Focusing on the Key Project of National Natural Science Foundation of China “A study on retrieving key ecological parameters in mountainous regions by remote sensing methods and evaluating their spatio-temporal representativeness”, this paper introduced the project background, objectives, research status, the key scientific questions, main contents of the research, the overall methodology and the deliverables. Choosing different topographic gradient and vegetation background, this project will conduct researches on retrieving key ecological parameters such as LAI and NPP in mountainous areas, evaluating their spatio-temporal representativeness, analyzing the influence of complex terrain on remote sensing signals and the remote sensing products, and finally trying to make a breakthrough in the theory and methodology of ecological parameters retrieving in mountains area.     

Random field characterization of uniaxial compressive strength and elastic modulus for intact rocks

Rock properties exhibit spatial variabilities due to complex geological processes such as sedimentation,metamorphism, weathering, and tectogenesis. Although recognized as an important factor controlling the safety of geotechnical structures in rock engineering, the spatial variability of rock properties is rarely quantified. Hence, this study characterizes the autocorrelation structures and scales of fluctuation of two important parameters of intact rocks, i.e. uniaxial compressive strength(UCS) and elastic modulus(EM).UCS and EM data for sedimentary and igneous rocks are collected. The autocorrelation structures are selected using a Bayesian model class selection approach and the scales of fluctuation for these two parameters are estimated using a Bayesian updating method. The results show that the autocorrelation structures for UCS and EM could be best described by a single exponential autocorrelation function. The scales of fluctuation for UCS and EM respectively range from 0.3 m to 8.0 m and from 0.3 m to 8.4 m.These results serve as guidelines for selecting proper autocorrelation functions and autocorrelation distances for rock properties in reliability analyses and could also be used as prior information for quantifying the spatial variability of rock properties in a Bayesian framework.     

Space,scale, and regional inequality in provincial China: A spatial filtering approach

This paper investigates regional inequality and development in China's Guangdong province by employing the multi-scale and multi-mechanism framework. The study further examines the relationship between space, scale, and regional inequality by applying a spatial filtering method that eliminates spatial dependence of the data and quantifies the extent to which spatial effects have contributed to regional inequality at multiple scales. The results suggest that over 90% of the divide between the core of the Pearl River Delta (PRD) and the periphery areas of Guangdong province can be explained by the effect of strengthening spatial dependence. By incorporating spatial filters in space-time models, we also reveal the space-time and core-periphery heterogeneities of development mechanisms. Our study confirms that the integration of a multi-scale and multi-mechanism framework and rigorous spatial analysis methods, such as spatial filtering and space-time modeling, helps better understand the complexity of regional development in China.     

Comparative spatial inequality dynamics: The case of Mexico and the United States

In this paper we examine the trajectory of regional income inequality dynamics for two neighboring national systems. Using data on 3038 US counties and 2418 Mexico municipios, from 2000, 2005, and 2010, we employ recent extensions of spatial Markov chains and space-time mobility measures, to consider the following questions: Are regional inequality dynamics fundamentally distinct between Mexico and the United States? Does the role of spatial context influence the distributional dynamics of the two systems? Finally we examine if there is a distinct international border region that displays inequality dynamics different from those of the internal regions of the two national systems. Strong evidence of spatial heterogeneity in regional income mobility is found between the two national systems, with Mexico having higher mobility relative to the US. The international border region is found to have distinct mobility dynamics from either national system, experiencing the strongest mobility. Extensive evidence of spatial contextual effects are found throughout the US-Mexican pooled data set indicating that a region's transitional dynamics are influenced by incomes of neighboring regions.     

Geographically-weighted regression analysis of percentage of late-stage prostate cancer diagnosis in Florida

This study assessed spatial context and the local impacts of putative factors on the proportion of prostate cancer diagnosed at late-stages in Florida during the period 2001–2007. A logistic regression was performed aspatially and by geographically-weighted regression (GWR) at the nodes of a 5 km spacing grid overlaid over Florida and using all the cancer cases within a radius of 125 km of each node. Variables associated significantly with high percentages of late-stage prostate cancer included having comorbidities, smoking, being Black and living in census tracts with farmhouses. Having private or public insurance, being married or diagnosed in a for-profit facility, as well as living in census tracts with high household income reduced significantly this likelihood. Geographically-weighted regression allowed the identification of areas where the local odds ratio is significantly different from the ratio estimated using aspatial regression (State-level). For example, the local odds ratios for the comorbidity covariates were significantly smaller than the State-level odds ratio in Tallahassee and Pensacola, while they were significantly larger in Palm Beach. This emphasizes the need for local strategies and cancer control interventions to reduce the percentage of prostate cancer diagnosed at late-stages and ultimately eliminate health disparities.     

Spatial and gender inequality in the Kenya certificate of primary education examination results

Kenya's 8-4-4 system of education consists of 8 years of primary education, 4 years of secondary education, and 4 years of university education. The system was introduced in 1985 with the primary aim of better aligning Kenya's education system with its development aspirations. In particular, the system sought to reduce youth unemployment by offering them life skills training as well as technical and vocational skills. At the completion of 8 years of primary education, students take the national Kenya Certificate of Primary Education (KCPE) exam which tests students in five courses: English, Kiswahili, mathematics, science, and social studies and religious education (SSR). However, since the adoption of the 8-4-4 system, no comprehensive study of the spatial distribution of KCPE exam scores, especially by gender has been done. Thus, this study examines nationwide performance on the 2011 KCPE exam by gender using Geographic Information Systems (GIS) and spatial statistics. Examination scores derived from approximately 17,217 public primary schools and 630,625 students were used in the study. Point pattern analysis was subsequently used to extract useful information from the dataset. A hot spot and cold spot analysis was then performed to see if unusual concentrations of scores exist in space in terms of overall performance, performance by gender, and individual subject scores. Our results show an existence of significant variability in terms of overall performance, performance by gender, and individual subject scores; with males outperforming females in mathematics, science, and SSR. Additionally, we found that proximity to major road networks and urban centers positively influences student performance on the KCPE exam probably because these factors influence the availability of educational resources (such as books and teachers), masterly of English (the language of instruction), teacher supervision, and child teachability.     

Monitoring socio-environmental change for sustainable development: Developing a Multidimensional Livelihoods Index (MLI)

To enable more effective monitoring of sustainable development for meeting targets of the post-2015 agenda, assessment is required at the sub-national level to better understand the spatial variation in factors which contribute to sustaining livelihoods. In this research we take Nepal as a case study; a nation consistently ranked as one of the poorest in the world. To understand how sustainable development can effectively promote livelihood diversification, we advocate that a multidimensional spatial approach is essential for monitoring social and environmental change to aid decision-making processes. To achieve this, a multidimensional index was created to spatially explore the landscape of livelihoods across rural Nepal. A methodology was developed to quantify the livelihoods asset pentagon (human-physical-social-financial-natural) of the Sustainable Livelihoods Framework. 23 socio-environmental indicators were selected to map the multidimensionality of livelihoods at the eco-development area unit level and produce the Multidimensional Livelihoods Index (MLI). Results indicate considerable spatial variability in the factors affecting people's livelihoods across Nepal. In general, the MLI decreases as you move north and east, reflecting changes in the topographic landscape and distance from the Kathmandu Valley Outcomes suggest an effective method for monitoring change at a sub-national level; highlighting potential locations and/or livelihood strategies for improving the targeting of resources (e.g. investment of foreign aid) to facilitate more sustainable development for the future.     

Mapping the popularity of urban restaurants using social media data

Nowadays, geographers show growing interest in providing location-based services for urban residents. It is of great practical significance to screen and recommend the most popular restaurants to consumers, as dining is important to every urban dweller. Consumer review website (CRW) has emerged as an active social media platform in catering industry. This paper demonstrated how to quantify the popularity of urban restaurants (PUR) by using CRW, namely, Dianping.com. An applied popularity index (PI) was developed to quantify PUR, based on the consumer review scores (food, service, and decoration) and physical data (evaluation frequency and restaurant grade) for 8259 restaurants within the Hangzhou city, China. All the information, together with the geographic location data, was harvested from the corresponding Application Programming Interface (API) platform. PUR was then mapped by using a geographic information system (GIS). Results showed that restaurants of high popularity were generally concentrated in old urban districts, whereas those in new urban districts presented low popularity. The kernel density distribution of PI also highlighted the geography that the PI values declined from the central city toward the outskirts. Locational associations between PUR and urban functional units (bank, shopping mall, school, cinema, hotel, bar, and scenic spot) generally presented a similar tendency. Restaurants with high PI values were in high proximity to urban functional units, whereas those with low PI values were located far away from other functional units. It implied that restaurants with high popularity tended to be located in high mixture with urban functional units. Although we used Dianping.com to perform the analysis, the presented methodology can be extended to other types of CRWs. Our study is believed to provide new insights into applied geographic sciences.     

Spatial distribution of nitrate health risk associated with groundwater use as drinking water in Merida,Mexico

Water containing nitrate levels above 45 mg/l is not recommended for human consumption and its prolonged intake is associated with various health conditions. In Merida city, Mexico, the only source for water supply is a karstic aquifer, but the absence of sewerage and drainage networks makes it highly vulnerable to anthropogenic contamination. In this work, the concentration and spatial distribution of nitrate in the Merida's karstic aquifer were assessed by statistical and geostatistical techniques. The sources of nitrate contamination were tracked by making statistical correlations between nitrate concentrations and key ions; the potential risk to human health was also estimated by using the Hazard Index (HI). A total of 177 groundwater samples were collected from the four water supply systems serving Merida, during 2012 and 2013. Nitrate concentrations from collected samples varied between 15.51 and 70.61 mg/l, with maximum and minimum concentrations per sampling point ranging from 47.47 to 70.61 mg/l and from 15.51 to 17.32 mg/l, respectively. Significant positive correlations (P < 0.05) between nitrates and chlorides, sulphates and potassium were found, which may indicate potential contamination from domestic wastewater and agricultural activities. The spatial distribution of nitrate concentrations in the aquifer revealed an increase in nitrates following a trajectory South–North West, towards central and northwestern zones within Merida Metropolitan Area. From the health risk analysis, it was found that infants exposed at current nitrate levels are at a higher risk (HI_MAX = 1.40) than adults (HR < 1.0) and therefore, there is a clear need for implementing effective strategies to protect groundwater quality and to better manage and control nitrate pollution sources.