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The Qinghai–Tibet Plateau has complex geomorphic features, which makes it difficult to interpolate surface air temperature precisely because of sparse samples and intensive spatial variations. Different interpolation methods have been developed, and they perform differently under various situations. The statistical errors of interpolation methods are determined by the population properties, the condition of the samples, and the adequacy of covariates. However, few studies have focused on optimal interpolation strategies for Qinghai–Tibet Plateau. In this study, seven typical interpolation models were used and compared. The model-based methods (e.g., ordinary kriging), design-based methods (inverse distance weight (IDW), thin plate splines (TPS), and combined methods (e.g., spatiotemporal regression kriging) were considered. Using auxiliary information, spatiotemporal ordinary kriging, and spatiotemporal stratified kriging models were built. Methods were evaluated by cross validation with mean absolute error (MAE) and root-mean-square error (RMSE). Results showed that for both of the index (RMSE, MAE), spatiotemporal kriging stratified by seasons (1.016 °C RMSE, 0.767 °C MAE) < spatiotemporal kriging stratified by climate regions (1.018 °C, 0.767 °C) < spatiotemporal ordinary kriging (1.022 °C, 0.774 °C) < spatiotemporal regression kriging (1.058 °C, 0.806 °C) < TPS (1.551 °C, 1.143 °C) < ordinary kriging (2.674 °C, 2.044 °C) < IDW (2.917 °C, 2.296 °C). In conclusion, under the condition of sparsely distributed stations and complex geomorphic features in the study area, taking advantages of time dimensional information, spatiotemporal heterogeneity and covariates (i.e., elevation) can improve interpolation precision effectively. [ABSTRACT FROM AUTHOR]

Prior studies of hand, foot, and mouth disease (HFMD) have often observed inconsistent results regarding meteorological factors. We propose the hypothesis that these meteorological associations vary in regions because of the heterogeneity of their geographical characteristics. We have tested this hypothesis by applying a geographical detector and Bayesian space–time hierarchy model to measure stratified spatiotemporal heterogeneity and local associations between meteorological factors and HFMD risk in five climate zones in China from January 2016 to December 2017. We found a significant spatial stratified heterogeneity in HFMD risk and climate zone explained 15% of the spatial stratified heterogeneity. Meanwhile, there was a significant temporal stratified heterogeneity of 14% as determined by meteorological factors. Average temperatures and relative humidity had a significant positive effect on HFMD in all climate zones, they were the most obvious in the southern temperate zone. In northern temperate, southern temperate, northern subtropics, middle subtropics and southern subtropics climate zone, a 1 °C rise in temperature was related to an increase of 3.99%, 13.76%, 4.38%, 3.99%, and 7.74% in HFMD, and a 1% increment in relative humidity was associated with a 1.51%, 5.40%, 2.21%, 3.44%, and 4.78% increase, respectively. These findings provide strong support for our hypotheses that HFMD incidence has a significant spatiotemporal stratified heterogeneity and different climate zones have distinct influences on the disease. These findings provide strong support for our hypotheses: HFMD incidence had significant spatiotemporal stratified heterogeneity and different climate zones had distinct influences on it. The study suggested that HFMD prevention and policy should be made according to meteorological variation in each climate zone. [ABSTRACT FROM AUTHOR]

Spatial spillovers and heterogeneity are rarely discussed in the migration flow pattern analysis, despite China's vast and diverse territory. This paper used spatial interaction model to capture the spatial features and relationships between migration flows and their potential factors. We found that migration flows were significantly characterized by geographic heterogeneity, spatial dependence and spillover. Spatial effects and population size exerted a tangible influence in relation to 2005–2015 migration flows within a given region and its surroundings. Promoting an urbanization policy affected the flows in the origin and destination regions differently. These findings revealed that the attractiveness of eastern coastal regions as destinations remained stronger than that of the central and western regions. Consequently, the trend of massive eastbound migration flow remains uncurbed despite the decade of urban development in the central and western regions. These findings also suggested that urbanization in central or western China will undergo circular promotion due to the increasing urbanization level itself. Smaller gaps will strengthen the synergetic development of population migration and urbanization between the regions and their neighbors. The new-type urbanization policy should focus on diminishing the disparities between coastal and inner regions. [ABSTRACT FROM AUTHOR]

Monoclonal antibody (mAb) coformulation containing two therapeutic proteins provides benefits of improved therapeutic efficacy and better patient compliance. Monitoring of the individual mAb stability in the coformulation is critical to ensure its quality and safety. Among post-translational modifications (PTMs), oxidation is often considered as one of the critical quality attributes (CQAs) as it potentially affects the structure and potency. Although hydrophobic interaction chromatography (HIC) and reversed phase liquid chromatography (RPLC) have been used to monitor overall protein oxidation, mass spectrometry of peptide digests resolved by LC methods can afford superior selectivity and sensitivity for specific PTMs. With the advent of the Quadrupole Dalton (QDa) mass spectrometer as an affordable add-on detector, implementation of targeted oxidation assays in development and quality control (QC) laboratories is now feasible. In this study, as the first effort to implement MS-based methods for antibody coformulation in QC laboratories, we developed and validated a high-throughput and robust focused peptide mapping method using QDa for simultaneous site-specific monitoring of oxidation of methionine and tryptophan residues in heavy-chain (HC) complementary determining regions (CDRs) of two co-formulated mAbs. The method was validated in terms of accuracy, precision, linearity, range, quantitation limit (QL), specificity, and solution stability per recommendations in ICH Q2. The method robustness was systematically assessed involving multiple sample preparation and instrument method parameters. The method met the validation criteria in GMP laboratories with excellent robustness and was implemented in both GMP and development environments. [ABSTRACT FROM AUTHOR]

Previous studies indicate that the incidence of bacillary dysentery is closely related to meteorological factors. However, the impact of temperature and the spatial heterogeneity of the disease in regions of unbalanced socioeconomic development remains unclear. Therefore, this research collected data for 29,639 daily bacillary dysentery cases in children under 5 years of age, as well as the meteorological variables from China's Beijing–Tianjin–Hebei region, to analyze the spatial pattern of bacillary dysentery and reveal its nonlinear association with temperature. The SatScan method was employed first, to detect the spatial heterogeneity of the disease risk, and then the distributed lag nonlinear model (DLNM) was used to analyze the relationships between the daily minimum, mean, and maximum temperatures and bacillary dysentery in the stratified heterogeneous regions. The results indicated that bacillary dysentery incidence presented statistically significant spatial heterogeneity. The area of highest risk was found to be Beijing and its neighboring regions, which have high population densities. There was also a positive association between bacillary dysentery and temperature. Hotter temperatures were accompanied by higher relative risks. In the most likely spatial cluster region, the excess risk (ER) values for a 1°C rise in minimum, mean, and maximum temperatures above the median were 4.65%, 11.30%, and 19.21%, respectively. The effect of temperature on bacillary dysentery peaked at a lag of 3 to 4 days. The findings of this study will aid risk assessments and early warning systems for bacillary dysentery. [ABSTRACT FROM AUTHOR]

Assessing the association between maps is a basic task in GIS. It not only helps to discover the consistency between mapped distributions and to reveal the relationship between various spatial patterns, but also implies attribution. Although literatures are rich in the map association measures, their applications are still tricky because of the complexity in spatial data. In this study, we investigate nine representative measures of map association, where each map could be in three scales of measurement: nominal, ordinal and quantitative (interval or ratio). The strengths and limitations of individual methods are addressed and compared, which include their applicability to different measurement scales, interpretability, and potential applications in complex scenarios. The theoretical comparisons are then demonstrated by two empirical examples. These works provide a rule of thumb for the selection of map association measures for practical purposes. [ABSTRACT FROM AUTHOR]

Hand, foot, and mouth disease (HFMD), predominantly occurs among infants and children. Previous studies have shown that suitable, stable temperatures favor HFMD virus reproduction; however, temperature fluctuations also affect virus transmission, and there are, so far, no studies concerning the association between such fluctuations and the incidence of HFMD. The objective of this study was to map the spatial-temporal distribution of HFMD incidence and quantify the long-term effects of temperature fluctuations on HFMD incidence in children. HFMD cases in children under five, from January 2009 to December 2013, in Beijing, Tianjin, and Hebei provinces of China, were used in this study. The GeoDetector and Bayesian space-time hierarchy models were employed to explore the spatial-temporal association between temperature fluctuations and HFMD incidence. The results indicate that HFMD incidence had significant spatial stratified heterogeneity (GeoDetector q-statistic = 0.83, p < 0.05), and that areas with higher risk mainly appeared in metropolises and their adjacent regions. HFMD transmission was negatively associated with temperature fluctuations. A 1 °C increase in the standard deviation of maximum and minimum temperatures was associated with decreases of 8.22% and 11.87% in the risk of HFMD incidence, respectively. The study suggests that large temperature fluctuations affect virus growth or multiplication, thereby inhibiting the activity of the virus and potentially even leading to its extinction, and consequently affecting the spatial-temporal distribution of HFMD. The findings can serve as a reference for the practical control of this disease and offer help in the rational allocation of medical resources. [ABSTRACT FROM AUTHOR]

The Huai River basin (located in eastern China) has a population of 180 million and has the highest risk of esophageal cancer (EC) mortality in China. Some studies found that contaminants in drinking water are a major risk factor for cancers of the digestive system. However, the effect of water pollution in the historical period on the current EC mortality remains unclear. Data were collected on the EC mortality rate in 2004 in the Huai River basin in 11 counties, and data on the surface water quality in the region from 1987 to 2004 were used. The Pearson correlation and the GeoDetector q-statistic were employed to explore the association between water pollution and the EC mortality rate in different lag periods, from linear and nonlinear perspectives, respectively. The study showed apparently spatial heterogeneity of the EC mortality rate in the region. The EC mortality rate downstream is significantly higher than that in other regions; in the midstream, the region north of the mainstream has a lower average mortality rate than that south of the area. Upstream, the region north of the mainstream has a higher mortality rate than that in the southern area. The spatial pattern was formed under the influence of water pollution in the historical period. 1996, 1997, and 1998 have the strongest linear or nonlinear effect on the EC mortality rate in 2004, in which the Pearson correlation coefficient and the q-statistic were the highest, 0.79 and 0.89, respectively. Rapid industrialization in the past 20 years has caused environmental problems and poses related health risks. The study indicated that the current EC mortality rate was mainly caused by water pollution from the previous 8 years. The findings provide knowledge about the lag time for pollution effects on the EC mortality rate, and can contribute to the controlling and preventing esophageal cancer. [ABSTRACT FROM AUTHOR]

Local-scale landslide susceptibility mapping (LSM) provides detailed information for decision making and planning. Most published landslide susceptibility maps lack reliable information at the local scale due to the spatial heterogeneity being ignored. To enrich the local-scale information of LSM, multiple information fusion methods for the local spatial heterogeneity and regional trends of control factors are needed. However, no information fusion method has been proposed for LSM yet. In this paper, we developed a new integrated statistical method, named B-GeoSVC, under the hierarchical Bayesian framework for LSM. Specifically, this model applied the GeoDetector method to fit the regional trends of control factors and employed spatially varying coefficients (SVC) model to fit the local spatial heterogeneity of each control factor. Then, the regional trends and local spatial heterogeneity information were fused within the hierarchical Bayesian framework. The B-GeoSVC model was verified using data from the Duwen basin of China, which was in the central region affected by the MS 8.0 Wenchuan earthquake that occurred on May 12, 2008. Under a cross-validation experiment, the prediction accuracy rate of the B-GeoSVC model was 86.09%, and the area under the curve was 0.93, which suggested that the B-GeoSVC model was able to achieve relatively accurate local-scale LSM and provide richer local information than traditional regional scale LSM. More importantly, not only the B-GeoSVC model could be employed as a general solution to fuse both regional and local-scale information for landslide mapping, but also offer new insights into the broader earth science and spatial statistics. [ABSTRACT FROM AUTHOR]

Rodents are the main host animals that spread plague, and Spermophilus dauricus (S. dauricus) is the most common rodent in North China. In this study, a rodent density survey was carried out in China's Jilin Province from April to August 2005. Moran's I and semivariogram curves were used to investigate the spatial distribution characteristics of the sampling data. We found that the spatial auto-correlation index was low and failed to generate a meaningful semivariogram curve. In this case, commonly used interpolators, such as kriging, were not suitable for mapping density over the study area. However, the Sandwich model, which is based on spatial stratified heterogeneity, could be applied to our data. Our results showed that the type of soil and land use significantly influenced the distribution of rodent density, and the interactive effect of these variables was much stronger than that of each variable alone. The Sandwich-estimated rodent density map showed that rodent density increased from the southeast to the northwest in Jilin Province. Finally, a framework of a rodent density survey using the Sandwich model was introduced. [ABSTRACT FROM AUTHOR]

The influence of monsoon climatic characteristics makes the tropics of China different from those of other parts of the world. Therefore, the location of the northern boundary of China's tropical zone has been one of the most controversial issues in the study of comprehensive physical regionalisation in China. This paper introduces developments in the study of the northern boundary of China's tropical zone, in which different scholars delimit the boundary with great differences based on different regionalisation objectives, indexes, and methods. The main divergence of opinion is found in different understandings of zonal vegetation, agricultural vegetation type, cropping systems, tropical soil type and tropical characteristics. In this study, we applied the GeoDetector model, which measures the spatial stratified heterogeneity, to validate the northern boundaries of the tropical zone delimited by six principal scholars. The results show that the mean q-statistic value of the higher latitude boundary delimited by Ren Mei'e is the largest ( q=0.37), suggesting that, of the rival views, it best reflects the regional differences between China's tropical and subtropical zones, but it is not necessarily suitable for guiding the development of tropical agriculture. The mean values of the q-statistics of Zheng Du's line and Yu Xianfang's line around the Leizhou Peninsula at a lower latitude were smaller, at 0.10 and 0.08 respectively, indicating that the regional differences were smaller than those of Ren Mei'e's boundary. Against the background of global climate change, the climate itself is changing in fluctuation. It is, thus, worth our further research whether the northern boundary of the tropical zone should not be a fixed line but rather should fluctuate within a certain scope to reflect these changes. [ABSTRACT FROM AUTHOR]

Built-in electric field may enhance or retard the impurity-free vacancy disordering (IFVD) during rapid thermal annealing (RTP) by imposing a drift on charged point defects. Built-in electric field is at the interface between dielectric layer and top layer of the structure. Subsequent rapid thermal annealing leads to different intermixing results due to different field directions on InP cap layers in different doping types. Experimental results also show different influences of the built-in field on the two sublattices largely due to different charge numbers of point defects. [ABSTRACT FROM AUTHOR]