Integrating land-sea coordination into construction of an ecological security pattern for urban agglomeration: a case study in the Guangdong-Hong Kong-Macao Greater Bay Area.

The construction of ecological security pattern (ESP) is of great scientific significance for solving the problem of habitat fragmentation in urban environment. However, previous studies mainly focused on the ESP in land area, leaving the sea area to be ignored. This study took the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) and its offshore area as an example and integrated the land-sea coordination into the construction of ESP based on the minimum resistance model, gravity model, and graph theory centrality. The results showed that there are 171 and 56 ecological sources for land area and offshore area, accounting for 31.46% and 21.51% of total area, respectively. Twenty-four important ecological corridors with a total length of 2738.05 km were identified in GBA, and the width is proposed to be less than 100 m. Moreover, the α, ß, and γ index of the ecological network in the study area is 0.19, 1.33, and 0.5, respectively, indicating that the ecological network structure is complex and the connectivity between ecological nodes is good. The ecological restoration area includes 286.6 km2 of ecological pinch points and 140.44 km2 of ecological barrier. The overall ESP of the study area is "one ring, two belts, and four zones." The main body of the area with a superior ecological environment is distributed in a ring-like pattern near the outer edge of the study area, and two belts (important ecological corridor and ecological corridor) are distributed in a network. According to the ecological characteristics, the study area was divided into four zones: ecological preservation areas, ecological restoration areas, limited construction areas, and optimized construction areas. The ESP established herein institute provides a reference for the revision of ecological space control and optimization measures in the GBA. It also provides effective and systematic means to solve ecological problems in the current territorial spatial planning and territorial ecological restoration of coastal urban agglomeration.

Identifying Migration Routes of Wild Asian Elephants in China Based on Ecological Networks Constructed by Circuit Theory Model.

Humans overlap with Asian elephants, resulting in frequent costly human-elephant conflicts, which disturb and even threaten local residents. In this study, we treat provincial and national nature reserves where Asian elephants still exist and other alternative habitats suitable for Asian elephants in southern Yunnan, China, as ecological patches. By using this approach, we can treat the terrain and surface state factors that hinder the migration of Asian elephants as a form of ecological resistance surface. We can then use a circuit theory model and remote sensing data to construct an ecological network, which allows us to identify ecological corridors and ecological pinch points. Herein, the possible migration routes of wild Asian elephants were identified. The main results are as follows: (1) In the study area, dense forests with steep slopes and high altitudes, cultivated land, and building land have greater migration resistance, while the gently undulating shrubs, bamboo forests, and grasslands far away from the city have less migration resistance. (2) There are three ecological corridor groups in the study area, mainly composed of shrub and grassland. The ecological corridors identified in this paper are the most likely migration routes of wild Asian elephants in China, and areas with higher simulated current densities reflect a higher probability of Asian elephants passing through. (3) According to the analysis, the ecological pinch points in the study area are 602 km2 in total, and woodland and grassland account for 89.2% of the total ecological pinch area. The areas where the pinch points are located have a high probability of Asian elephants passing through and a narrow space. Our findings can provide suggestions and solutions for the current conservation of wild Asian elephant species, alleviate human-elephant conflicts, promote the harmonious coexistence between humans and nature, and provide reference for biological protection and biological reserve planning.

Light grazing facilitates carbon accumulation in subsoil in Chinese grasslands: A meta-analysis.

Grazing by livestock greatly affects the soil carbon (C) cycle in grassland ecosystems. However, the effects of grazing at different intensities and durations on the dynamics of soil C in its subsoil layers are not clearly understood. Here, we compiled data from 78 sites (in total 122 published studies) to examine the effects of varying grazing intensities and durations on soil C content at different depths for grasslands in China. Our meta-analysis revealed that grazing led to an overall decrease in soil C content and productivity of above-ground vegetation (e.g., above-ground biomass and litter) but an increase in below-ground biomass. Specifically, the effects of grazing on soil C content became less negative or even positive with increasing soil depths. An increase of soil C content was consequently found under light grazing (LG), although soil C content still decreased under moderate and heavy grazing. The increase in soil C content under LG could be largely attributed to the increase of soil C content in subsoil layers (>20 cm), despite that soil C content in surface soil layer (0-20 cm) decreased. Moreover, the magnitude of increase in soil C content under LG in subsoil layers increased with grazing duration. A possible reason of the increase in soil C content in the subsoil layers was due to the increases in below-ground biomass. Our study highlights that LG may modify the allocation of C input and promote its accumulation in subsoil layers, thus offsetting the negative impact of grazing on surface soil C content, a finding that has significant implications for C sequestration in grasslands.

Revealing the spatio-temporal variability of evapotranspiration and its components based on an improved Shuttleworth-Wallace model in the Yellow River Basin.

Identifying the spatio-temporal variations of evapotranspiration (ET) from its components (soil evaporation and plant transpiration) can greatly improve our understanding of water-cycle and biogeochemical processes. However, partitioning evapotranspiration into evaporation (E) and transpiration (T) at regional scale with high accuracy still remains a challenge. This study has aimed to reveal the spatio-temporal variations of evapotranspiration and its components by using an improved Shuttleworth-Wallace (SWH) model to partition ET in the Yellow River Basin during 1981-2010. The environmental factors affecting the spatial and temporal variations of evapotranspiration and its components were also assessed. Results showed that the mean annual ET, T and E in the Yellow River Basin were 372.18 mm, 179.64 mm, and 192.54 mm, respectively, over the last 30 years. The spatial pattern of mean annual ET and T displayed a decreasing trend from southeast to northwest in the Yellow River Basin, and the temporal variation showed a significant increasing trend with rates of 1.72 mm yr-1 and 1.54 mm yr-1, respectively. It meant that T accounted for the variations of ET, while E showed no significant changes in recent decades. Moreover, the normalized differential vegetation index (NDVI) and temperature were identified as the main factors controlling the variations of ET and T in the Yellow River Basin. Among them, the area with NDVI as the dominant factor for ET and T could reach 63.82% and 78.47% of the whole basin respectively. However, the variations of E were affected by complex factors, and evaporation in the western alpine region was mainly controlled by temperature. Our findings are expected to not only have implications for developing sustainable policies of water management and ecological restoration in this region, but also provide valuable insight in methodology of ET partitioning in regional or global scale.

Prevalence of allergen sensitization among 1,091 patients with urticaria.

The etiology of urticaria is heterogeneous and allergic responses may be involved in it. The aim of the present study was to investigate the prevalence and distribution of sensitivity to inhaled and food allergens among patients with urticaria in Henan province (China). The levels of specific immunoglobulin E (sIgE) were detected using the AllergyScreen test and a total of 524/1,091 cases (48.0%) tested positive for sIgE to at least one of the 19 allergens. The most common inhaled allergens the urticaria patients were sensitive to were D. pteronyssinus (34.5%), cockroach (12.5%) and tree pollen mix (11.1%), while the food allergens with the highest rate of allergic reactions were cashew nut (8.1%), shrimp (6.8%) and crab (6.4%). The positive rates for D. pteronyssinus, dog hair, cockroach, mold mix, tree pollen mix and shrimp in the chronic urticaria group were higher than those in the acute urticaria group (P<0.05). Furthermore, positive rates for the majority of allergens were higher in males than in females and were significantly different between age groups (P<0.05). The results of the present study provided information on the characteristics of allergen sensitization of patients with urticaria and may facilitate the prevention, diagnosis and management of urticaria in Henan province.

[Effect of Sludge Retention Time and pH on the Denitrifying Phosphorus Removal Process].

In this work, the effects of the sludge retention time (SRT, 35, 25, or 15 d) and pH (7.5, 8.0, 8.5) on denitrifying phosphorus removal were investigated using denitrifying phosphorus bacteria (DPBs) enriched in a sequencing batch reactor (SBR). The results indicated that shortening the SRT from 35 d to 25 d resulted in a decrease in the mixed liquor volatile suspended solids (MLVSS) from 2821 to 2301 mg·L-1, while the sludge loading rate (F/M) increased from 0.256 kg·(kg·d)-1to 0.312 kg·(kg·d)-1. Although the quantity of net phosphorus release and net phosphorus uptake decreased at this stage, the rates of anaerobic phosphorus release, anoxic phosphorus absorption, and denitrification reached their highest levels with values of 25.07, 15.92, and 9.45 mg·(g·h)-1, respectively, due to the increased sludge activity. Consequently, the phosphorus content of the sludge increased from 4.78% to 5.33%, and the removal rate of PO43--P was stable at above 95% with an average effluent PO43--P concentration below 0.5 mg·L-1. When the SRT was further shortened to 15 d, the MLVSS decreased to values as low as 1448 mg·L-1, and the proportion of DPBs in the phosphorus accumulating organisms (PAOs) decreased from 82.4% to 65.7%, indicating that the DPBs were gradually washed out from the system due to the excessively short SRT. At this stage, the phosphorus content of sludge decreased to 3.43%, while the rates of phosphorus release, phosphorus absorption, and denitrification also decreased to some extent. When the pH was increased (7.5-8.0), the anaerobic phosphorus release rate and the anoxic phosphorus absorption rate also increased, and reached 25.86 mg·(g·h)-1 and 16.62 mg·(g·h)-1, respectively, at a pH of 8.0. When the pH exceeded 8.0, the phosphorus removal efficiency dropped rapidly, supposedly due to phosphorus chemical precipitation.

[Start-up and Stable Operation of ABR-MBR Denitrifying Phosphorus Removal Process].

The nitrogen and phosphorus removal characteristics during the start-up and the long-term operational stability of an anaerobic/anoxic (A/A) ABR coupled aerobic MBR system treating low C/N domestic wastewater were investigated. The results showed that the denitrifying phosphorus bacteria (DPBs) were successfully enriched within 46 d by controlling the nitrate recycling ratio (increasing from 150% to 300%), with a temperature of 30℃±2℃, volume loading rate of 0.8 kg·(m3·d)-1 and sludge reflux ratio of 80% in the ABR, sludge retention time (SRT) in the denitrifying phosphorus removal functional area of 25 d, and the dissolved oxygen (DO) of 1-2 mg·L-1 in the MBR. The net phosphorus release and phosphorus uptake of DPBs reached 20.56 mg·L-1and 27.74 mg·L-1, respectively. Batch tests demonstrated that about 84.8% of phosphorus-accumulating organisms (PAOs) could use NO3--N as an electron acceptor for denitrifying phosphorus removal. After 50 d of stable operation after the successful system start-up, the average removal rates of COD, NH4+-N, TN, and PO43--P were 91.8%, 99.0%, 71.5%, and 94.2%, respectively. The results also suggested that 0.83 mg·L-1NO3--N was consumed per 1 mg·L-1 PO43--P removed during the denitrifying phosphorus removal, indicating that the simultaneous nitrogen and phosphorus removal was achieved in the ABR-MBR system.

Construction of ecological network using morphological spatial pattern analysis and minimal cumulative resistance models in Guangzhou City, China.

Construction of ecological network is important for improving urban ecological environment under the scenarios of rapid urbanization. We extracted the core area with good connectivity as the ecological sources with the methods of morphological spatial pattern analysis (MSPA) and landscape index with Guangzhou City as the study area. The ecological network was then constructed by minimal cumulative resistance (MCR) model and was quantitatively analyzed by gravity model and connectivity indices. After that, an optimized ecological network was finally constructed. The results showed that ten core patches could be used as ecological sources. In addition, eighteen important corridors as well as twenty-seven general corridors were identified, which were mainly distributed in the northeast part of the city. Five more ecological sources and thirteen more planning corridors were suggested under the optimized ecological network. Our results indicated that forests were the main composition of ecological corridors. The appropriate width for the important corridor and planning corridor was 60-100 m and 30-60 m, respectively. Our results provide scientific guidance for designing urban ecological network.

[Seasonal divergence in the responses of vegetation growth to PDO in Tibetan Plateau, China]. / 青藏高原植被生长对PDO响应的季节分异.

Regional-scale normalized difference vegetation index (NDVI) derived from satellite remote sensing observations and gridded climate data were used to study the seasonal responses and underlying mechanisms of vegetation growth over Tibetan Plateau to Pacific Decadal Oscillation (PDO) at period of 1982-2015, by performing Spearman correlation analysis and enhanced multivariate regression model: structural equation model (SEM). The results showed that there was significant negative correlation between PDO index and mean growing-season (April-October) NDVI over Tibetan Plateau; however, marked seasonal divergence in the relationship between PDO and vegetation growth existed among different seasons. It characterized with stronger negative correlation between PDO and NDVI in autumn than in summer, and winter PDO had significant effect on consequent summer vegetation growth. Additionally, it showed great divergence in control processes of PDO on vegetation growth among different seasons, with significant control of PDO on both temperature and precipitation in summer, and significant control of PDO on temperature only in autumn.

[A Systematic Review of the Value of Thrombelastography or Thromboelastometry for Prediction of Venous Thromboembolism].

OBJECTIVE: To systematically collect the thrombelastography (TEG)-or thromboelastometry (ROTEM)-related data, and predict to evaluate their values for the prediction of thromboembolic events. METHODS: Databases including PubMed, Central and Embase were searched for the related clinical trials, and the references were retrieved manually; these included references were assessed qualitatively by the QUADAS-2 tool; finally the enrolled researches were qualitatively analyzed. RESULTS: A total of 15 studies consisting of 293 VTE patients met the inclusion criteria. The overall quality and the accuracy of TEG or ROTEM in predicting VTE varied a lot. Two thirds of the studies displayed that the changes of TEG parameters or ROTEM were related to the occurrence of VTE. CONCLUSION: The present studies showed that the TEG or ROTEM for predicting the VTE display higher difference in accuracy, therefore, the combination of TEG or ROTEM with other laboratory tests may improve the accuracy of VTE diagnosis.

[A virological response study of serum leptin level and insulin resistance on the antivirus effect in patients with chronic hepatitis C].

OBJECTIVE: To study the serum leptin level and insulin resistance on sustained virological response (SVR) in patients with chronic hepatitis C and to evaluate whether serum leptin level and insulin resistance are independent risk factors. METHODS: Forty chronic hepatitis C patients were treated with interferon (alpha-2a) 5 MU and ribavirin 1.0 g for 24 weeks. The fasting serum leptin, insulin, glucose, HCV RNA load, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were measured and the insulin resistance index (HOMA-IR: homeostasis model of assessment) and body mass index (BMI) were calculated. Statistical methods used were univariate analyses and multivariable regression analyses. RESULTS: Of the 40 patients, 23 patients (57.5%) had a sustained virological response and 17 patients (42.5%) had a non-sustained virological response. Patients with a sustained virological response had lower serum leptin, HOMA-IR and BMI. Their SVR was associated with age, HCV RNA loads, serum leptin level, and insulin resistance, when analyzed with univariate analyses. SVR was not associated with sex, ALT, or AST. With multivariable regression analyses, serum leptin level and insulin resistance were found to be independent prediction factors for SVR in chronic hepatitis C patients with antivirus treatment. CONCLUSION: Serum leptin level and insulin resistance were associated with SVR in chronic hepatitis C patients; they were independent prediction factors for SVR.