Standardization of monitoring data reassesses spatial distribution of aquatic microplastics concentrations worldwide.

Microplastics are found in continental and oceanic waters worldwide, but their spatial distribution shows an intricate pattern. Their driving factors remain difficult to identify and widely discussed due to insufficient and unstandardized monitoring data. Here, based on in situ experiments and hundreds of river samples from the Qinghai-Tibet Plateau, we formulate a model to standardize aquatic microplastic measurements. The model was applied to existing data on a global scale. These data are standardized to a 20 µm mesh size, resulting in a new spatial distribution of aquatic microplastic densities, with average concentrations of 554.93 ± 1352.42 items/m3 in Europe, 2558.90 ± 4799.62 in North America and 1741.94 ± 3225.09 in Asia. Excessive contaminations (microplastic concentration > 104 items/m3) are in the Yangtze River, the Charleston Harbor Estuary, the Bodega Bay and the Winyah Bay. We show that, based on these standardized concentrations, new driving factors could be used to predict the global or regional microplastic distribution in continental waters, such as the Human Development Index with a correlation of 75.86% on a global scale, the nighttime lights with a correlation of 37.26 ± 0.30% in Europe and 39.02 ± 0.54% in Asia, and the Mismanagement Plastic Waste with a correlation of 61.21 ± 19.86% in North America. Mapping standardized concentrations of aquatic microplastics enables a better comparison of contamination levels between regions and reveals more accurate hotspots to better adapt remediation efforts and future plastic pollution scenarios.

Testing Conditional Independence Between Latent Variables by Independence Residuals.

Conditional independence (CI) testing is an important problem, especially in causal discovery. Most testing methods assume that all variables are fully observable and then test the CI among the observed data. Such an assumption is often untenable beyond applications dealing with, e.g., psychological analysis about the mental health status and medical diagnosing (researchers need to consider the existence of latent variables in these scenarios); and typically adopted latent CI test schemes mainly suffer from robust or efficient issues. Accordingly, this article investigates the problem of testing CI between latent variables. To this end, we offer an auxiliary regression-based CI (AReCI) test by taking the measured variable as the surrogate variable of the latent variables to conduct the regression over the latent variables under the linear causal models, in which each latent variable has some certain measured variables. Specifically, given a pair of latent variables LX and LY , and a corresponding latent variable set LO , [Formula: see text] holds if and only if [Formula: see text] and [Formula: see text] are statistically independent, where A' and A'' are the two disjoint subset of the measured variable for the corresponding latent variables, A'{LO} ∩A''{LO} = ∅ , and ω1 is a parameter vector characterized from the cross covariance between A{LX} and A'{LO} , and ω2 is a parameter vector characterized from the cross covariance between A{LY} and A''{LO} . We theoretically show that the AReCI test is capable of addressing both Gaussian and non-Gaussian data. In addition, we find that the well-known partial correlation test can be seen as a special case of the AReCI test. Finally, we devise a causal discovery method by using the AReCI test as the CI test. The experimental results on synthetic and real-world data illustrate the effectiveness of our method.

Equilibrium partitioning behaviors and remobilization of trace metals in the sediment profiles in the tributaries of the Three Gorges Reservoir, China.

Geochemical behaviors of trace metals in the sediment profiles are crucial for predicting the associated environmental risks in aquatic ecosystems. However, the comprehensive transport of trace metals under both equilibrium and dynamic conditions is still unclear under the changing hydrological regime. Here, the equilibrium partitioning behaviors and remobilization of five trace metals (Ni, Cu, Zn, As, and Pb) in sedimentary profiles within the tributaries of the Three Gorges Reservoir were explored by the partitioning coefficient (Kd), diffusive gradients in thin films (DGT), and DGT induced flux in sediments (DIFS) model. According to the Kd values, As posed the highest migration ability among the trace metals in the sediment profiles under equilibrium circumstances. Similarly, the dynamic processes of trace metals simulated by the DIFS model also suggested that As displayed the highest desorption rate despite having the lowest labile pool size. Moreover, all trace metals were classified as the "partially sustained" case, while the supply abilities of As and other trace metals were limited by the diffusion and the desorption kinetics, respectively. In addition, DGT-labile trace metals showed a diffusion trend from the sediment to the water column (except for Zn) at the sediment-water interface, indicating potential risks to water quality. Specifically, the equilibrium partitioning behaviors revealed the potential labile pool of trace metals in the solid phase, and the dynamic resupply process between the solid phase and porewater remained undetermined. In comparison, although DGT simulated the kinetic process of trace metals in the sediments, the labile pool of the trace metals could not be obtained. This study provided a holistic insight into the complementary trace metal behaviors under both equilibrium and dynamic conditions in the sediment and was beneficial to the water quality protection and internal pollution remediation in the aquatic environment.

THPs: Topological Hawkes Processes for Learning Causal Structure on Event Sequences.

Learning causal structure among event types on multitype event sequences is an important but challenging task. Existing methods, such as the Multivariate Hawkes processes, mostly assumed that each sequence is independent and identically distributed. However, in many real-world applications, it is commonplace to encounter a topological network behind the event sequences such that an event is excited or inhibited not only by its history but also by its topological neighbors. Consequently, the failure in describing the topological dependency among the event sequences leads to the error detection of the causal structure. By considering the Hawkes processes from the view of temporal convolution, we propose a topological Hawkes process (THP) to draw a connection between the graph convolution in the topology domain and the temporal convolution in time domains. We further propose a causal structure learning method on THP in a likelihood framework. The proposed method is featured with the graph convolution-based likelihood function of THP and a sparse optimization scheme with an Expectation-Maximization of the likelihood function. Theoretical analysis and experiments on both synthetic and real-world data demonstrate the effectiveness of the proposed method.

Analysis of the relationship between water and energy in China based on a multi-regional input-output method.

The shortage of water and energy are hindering the rapid development of the regional economy in recent years. Therefore, exploring the synergy of water and energy and managing the two resources comprehensively is conducive to the sustainable development of the economy. Based on the multi-regional input-output (MRIO) model, this study proposed a new assessment framework for investigating the water-energy (WE) relationship. We used this novel framework to identify the relationships in different sectors. The achieved results are as follows. First, water and energy are closely related in many sectors, including agriculture, extractive sector, petroleum, coking, and nuclear fuel processing sector, and other sectors. However, the construction sector, textile and clothing sector, and wood processing and furniture manufacturing sector showed low correlation (p > 0.05). Second, on the whole, the WE relationship has been improving. Among the eight regions, the relationship varies greatly, and the Southern coastal region has the best relationship (r = 0.78). Third, the spatial distribution of water and energy footprints shows high agreement. Although the virtual water and energy flows alleviated the energy pressure in Coastal areas, it has aggravated the water and energy shortages in Central areas. Therefore, identification of key sectors and construction of suitable policies may help alleviate the contradiction between water and energy shortages and drive regional economic development.

Effects of Content of Soil Rock Fragments on Soil Erodibility in China.

Soil erosion is serious in China-the soil in plateau and mountain areas contain a large of rock fragments, and their content and distribution have an important influence on soil erosion. However, there are still no complete results for calculating soil erodibility factor (K) that have corrected rock fragments in China. In this paper, the data available on rock fragments in the soil profile (RFP); rock fragments on the surface of the soil (RFS); and environmental factors such as elevation, terrain relief, slope, vegetation coverage (characterised by normalised difference vegetation index, NDVI), land use, precipitation, temperature, and soil type were used to explore the effects of content of soil rock fragments on calculating of K in China. The correlation analysis, typical sampling area analysis, and redundancy analysis were applied to analyse the effects of content of soil rock fragments on calculating of K and its relationship with environment factors. The results showed that (1) The rock fragments in the soil profile (RFP) increased K. The rock fragments on the surface (RFS) of the soil reduced K. The effect of both RFP and RFS reduced K. (2) The effect of rock fragments on K was most affected by elevation, followed by terrain relief, NDVI, slope, soil type, temperature, and precipitation, but had little correlation with land use. (3) The result of redundancy analysis showed elevation to be the main predominant factor of the effect of rock fragments on K. This study fully considered the effect of rock fragments on calculating of K and carried out a quantitative analysis of the factors affecting the effect of rock fragments on K, so as to provide necessary scientific basis for estimating K and evaluating soil erosion status in China more accurately.

Water-energy-carbon nexus in China's intra and inter-regional trade.

Water consumption, energy use, and carbon emission are three related key anthropogenic impacts on the natural environment. China is the largest carbon emitter and energy consumer, with the serious unevenly distributed water resources. Therefore, investigating the water-energy-carbon (WEC) nexus is important for China's environmental footprint reduction. This study explores the relation between water utilization, energy consumption, and carbon emission in China, based on a multiregional input-output (MRIO) analysis. The WEC nexus is discussed comprehensively in consideration of the utilization of water and energy and the emission of carbon, as well as the trade to and from and the consumption activities in different sectors and provinces. Results show that water, energy, and carbon present significant consistency in production and consumption processes. Sectors with higher consumption coefficients dominate the transfer of virtual WEC. Although virtual WEC mainly transfers from less developed regions to relatively developed regions, Category 1 (i.e., WEC all import) and category 2 (i.e., WEC disaccord) present opposite results to and category 3 (i.e., WEC all export) provinces in terms of W-E and W-C nexus. The net water and energy transfers are significantly positively correlated in category 1 provinces, whereas both sides are negatively correlated in category 2 and 3 provinces. This phenomenon also exists in the relationship between net water and carbon transfers. The virtual water, as well as energy and carbon export pressures are dispersed in these export provinces. Findings of this study are expected to assist the government in decreasing the environmental footprints and achieve sustainable development in China.

The Impact of Residences and Roads on Wind Erosion in a Temperate Grassland Ecosystem: A Spatially Oriented Perspective.

The existence of residences and roads is an important way in which human activity affects wind erosion in arid and semiarid environments. Studies assessing the impact of these elements on wind erosion have only focused on limited plots, and their threat of erosion to the surrounding environment has been ignored by many studies. This study was based on spatially overlayed analysis of independent wind erosion distribution simulated by the revised wind erosion equation (RWEQ) and remote-sensing-image-derived residence and road distribution data. Wind erosion at different distances from residences and roads was quantified at the landscape scale of a typical temperate grassland ecosystem, explicitly demonstrating the crucial impacts of both elements on wind erosion. The results showed that wind erosion weakened as the distance from residences and roads increased due to the priority pathways of human activities, and the wind erosion around the residence was more severe than around the road. Human activities in the buffer zones 0-200 m from the residences most frequently caused severe wind erosion, with a wind soil loss of 25 t ha-1 yr-1 and a wind soil loss of approximately 5.25 t ha-1 yr-1 for 0-60 m from the roads. The characteristics of wind erosion variation in the buffer zones were also affected by residence size and the environments in which the residences were located. The variation in wind erosion was closely related to the road levels. Human activities intensified wind erosion mainly by affecting the soil and vegetation around residences and roads. Ecological management should not be limited to residences and roads but should also protect the surrounding environments. The findings of this study are aimed towards a spatial perspective that can help implement rational and effective environmental management measures for the sustainability of wind-eroded ecosystems.

[Developmental characteristics of biological soil crusts and their effects on soil water infiltration on karst slope]. / å–€æ–¯ç‰¹å¡é¢ç”Ÿç‰©ç»“çš®å‘è‚²ç‰¹å¾åŠå ¶å¯¹åœŸå£¤æ°´åˆ†å ¥æ¸—çš„å½±å“.

Biological soil crusts (BSCs), as a pioneer for vegetation restoration and crucial component of surface landscape, greatly affect land surface process. To explore the development of BSCs and its effects on soil water infiltration in karst region, we investigated the development of BSCs and analyzed the infiltration processes with different BSCs coverages (0, 28%, 40%, 70%, 97%) and rainfall intensities (42 and 132 mm·h-1) in simulating rainfall experiments on a typical karst slope. The results showed that there were significant differences in the development of BSCs for different land use types, whereas the spatial variation of BSCs development on the slope was not obvious under the same land use type. Compared to the bare plot, the presence of BSCs significantly increased surface roughness, the initial runoff generation time, and soil water infiltration. In the cases of light (42 mm·h-1) and intensive (132 mm·h-1) rainfall, the initial infiltration rate of BSCs covered plots were 1.7-1.9 times and 1.2-1.9 times as that of bare plot, while the average infiltration rate in BSCs covered plots were 2.5-3.0 times and 1.4-3.3 times as that of bare plot, respectively. The BSCs coverage was significantly positively correlated with the initial runoff production time. The critical values of facilitating infiltration of BSCs coverage were between 65% and 70% under the test rainfall intensities. For heavy rainfall events, the inhibiting effects of BSCs on surface runoff were weakened. Horton model was the most reliable one for describing the infiltration process on karst slope with BSCs, followed by Kostiakov model and Philip model. In conclusion, the spatial variability of BSCs development on the karst slope was higher. The presence of BSCs had a significant effect on soil permeability in karst region.

Quantification of river bank erosion by RTK GPS monitoring: case studies along the Ningxia-Inner Mongolia reaches of the Yellow River, China.

The Ningxia-Inner Mongolia reaches of the Yellow River suffer from bank erosion problems; in order to identify the bank erosion dynamics, Real Time Kinematic Global Positioning System (RTK GPS) was applied to monitor bank morphology at three sites: Taole Cropland (TC), Maobula Shrubland (MS), and Maobula Cropland (MC). The measured data were analyzed using the Geographical Information System (GIS) to quantify the volume and amount of bank erosion. To verify the feasibility of other means quantifying bank erosion including remote sensing image interpretation and Bank-Stability and Toe-Erosion Model (BSTEM) simulation, their results were compared with the directly monitored results by RTK GPS. Results show that the bank erosion moduli at the TC, MS, and MC sites are 12,762, 6681 and 44,142 t km-1 a-1 respectively based on RTK GPS measurements from 2011 to 2014, with the bank erosion amount varying between flood and non-flood seasons and among different years. The bank erosion quantified by remote sensing interpretation and BSTEM simulation agreed well with results from RTK GPS measurement. The main factors that influence bank erosion on the upper reaches of the Yellow River include land use in the bank area, bank height, and bank curvature. More rational land use along the Yellow River and stabilization of the river bank are required for this area. This study shows that RTK GPS monitoring is reliable and useful for bank erosion research, which has not yet been fully exploited. There is potential of applying remote sensing and model simulation to determine bank erosion of large rivers, while they should be combined and supported by field investigated data.

Integrated Ground-Based SAR Interferometry, Terrestrial Laser Scanner, and Corner Reflector Deformation Experiments.

An integrated sensor system comprised of a terrestrial laser scanner (TLS), corner reflectors (CRs), and high precision linear rail is utilized to validate ground-based synthetic aperture radar (GB-SAR) interferometric micro-displacement measurements. A rail with positioning accuracy of 0.1 mm is deployed to ensure accurate and controllable deformation. The rail is equipped with a CR on a sliding platform for mobility. Three smaller CRs are installed nearby, each with a reflective sticker attached to the CR's vertex; the CRs present as high-amplitude points both in the GB-SAR images and the TLS point cloud to allow for accurate data matching. We analyze the GB-SAR zero-baseline repeated rail differential interferometry signal model to obtain 2D interferograms of the test site in time series, and then use TLS to obtain a 3D surface model. The model is matched with interferograms to produce more intuitive 3D products. The CR displacements can also be extracted via surface reconstruction algorithm. Finally, we compared the rail sensor measurement and TLS results to optimize coherent scatterer selection and filter the data. The proposed method yields accurate target displacement results via quantitative analysis of GB-SAR interferometry.

Soil diversity as affected by land use in China: consequences for soil protection.

Rapid land-use change in recent decades in China and its impact on terrestrial biodiversity have been widely studied, particularly at local and regional scales. However, the effect of land-use change on the diversity of soils that support the terrestrial biological system has rarely been studied. Here, we report the first effort to assess the impact of land-use change on soil diversity for the entire nation of China. Soil diversity and land-use effects were analyzed spatially in grids and provinces. The land-use effects on different soils were uneven. Anthropogenic soils occupied approximately 12% of the total soil area, which had already replaced the original natural soils. About 7.5% of the natural soil classes in China were in danger of substantial loss, due to the disturbance of agriculture and construction. More than 80% of the endangered soils were unprotected due to the overlook of soil diversity. The protection of soil diversity should be integrated into future conservation activities.

[Retrospective analysis of 202 pathological autopsy cases in medical dispute].

OBJECTIVE: To analyze the characteristics of autopsies in medical dispute. METHODS: The data of 202 autopsy cases in medical disputes performed by the Department of Pathology of Jiangxi Medical College from January 2001 to December 2010 were retrospectively analyzed. RESULTS: The number of autopsy in medical disputes increased year by year. Neonatal, infant and 30 ≊ 60y were more common age groups in dispute; the gender ratio of male to female was 2:1 and more cases were from hospitals in rural areas. Most medical disputes came from in departments of pediatric, obstetrics and gynecology and general surgery. Death caused by cardiovascular diseases ranked at the first place. CONCLUSION: Autopsy is important in medical disputes to define the cause of death and to preserve evidence.

[Effects of no-tillage on soil water content and physical properties of spring corn fields in semiarid region of northern China].

Field experiments were conducted in 2006-2008 to study the effects of no-tillage on the spatiotemporal dynamics of soil water content and related soil physical properties in spring corn fields in Beijing region during growth season. In study period, the water storage in 0-100 cm soil layer in tillage and no-tillage treatments had the same variation trend with time and precipitation, but the water storage at different time periods and under different precipitations was 2.7%-30.3% higher in no-tillage treatment than in tillage treatment. When the precipitation was relatively abundant, the increment of soil water storage was somewhat increased, but no-tillage was still worth to be popularized in the regions relatively deficit in precipitation. Under no-tillage, the average water storage in 0-100 cm soil layer during the three growth seasons in 2006-2008 was 3.4%-12.8% higher than that under conventional tillage, and the increment of the water storage in 0-20 cm and 80-100 cm soil layers under no-tillage was higher than that in intermediate layer, with the highest increment reached 22.2%. No-tillage improved soil water-holding capacity and water use efficiency via decreasing soil bulk density, increasing soil porosity, and promoting the formation of soil water-stable aggregates, and thereby, promoted crop yielding. After 3 years no-tillage, the soil water use efficiency and spring corn yield were increased by 13.3% and 16.4%, respectively, compared with those under conventional tillage.

Links between environmental geochemistry and rate of birth defects: Shanxi Province, China.

The rate of birth defects in Shanxi Province is among the highest worldwide. In order to identify the impacts of geochemical and environmental factors on birth defect risk, samples of soil, water and food were collected from an area with an unusually high rate of birth defects (study area) and an area with a low rate of birth defects (control area) in Shanxi Province, China. Element contents were determined by ICP-OES, and the results were analyzed using a non-parametric test and stepwise regression. Differences in the level and distribution of 14 geochemical elements, namely arsenic (As), selenium (Se), molybdenum (Mo), zinc (Zn), strontium (Sr), iron (Fe), tin (Sn), magnesium (Mg), vanadium (V), calcium (Ca), copper (Cu), aluminum (Al), potassium (K) and sulfur (S) were thus compared between the study and control areas. The results reveal that the geochemical element contents in soil, water and food show a significant difference between the study area and control area, and suggest that the study area was characterized by higher S and lower Sr and Al contents. These findings, based on statistical analysis, may be useful in directing further epidemiological investigations identifying the leading causes of birth defects.

Glucocorticoids aggravate retrograde memory deficiency associated with traumatic brain injury in rats.

Administration of glucocorticoid to patients with head injury has previously been demonstrated to impair memory. We hypothesize that glucocorticoids promote post-traumatic hippocampal apoptosis, resulting in retrograde memory deficiency associated with traumatic brain injury (TBI). In the present study, we tested this hypothesis by measuring spatial memory deficiency in rats subjected to fluid percussion injury (FPI) and receiving dexamethasone (DXM at 0.5-10 mg/kg) or methylprednisolone (MP at 5-30 mg/kg); we also examined neuronal apoptosis in hippocampus. Adult male Wistar rats were trained for the acquisition of spatial memory, then subjected to FPI and tested for spatial reference memory on post-injury days 7 and 14 using the Morris Water Maze. Brain tissue from injured rats was examined 24 h to 2 weeks after injury. The percent time in the goal quadrant, which measures spatial reference memory, was significantly lower in injured rats receiving either high-dose DXM or MP than in control groups. TUNEL-positive cells in hippocampus were first detected 24 h post-injury, plateauing at 48h. The number of TUNEL-positive cells was significantly higher in injured rats treated with either DXM or MP. The data suggest that glucocorticoid therapy for TBI may increase neuronal apoptosis in hippocampus and, as a result, aggravate retrograde memory deficits induced by TBI.

Cellular internalization and in vivo tracking of thermosensitive luminescent micelles based on luminescent lanthanide chelate.

An amphiphilic tris(dibenzoylmethanato)europium(III) (Eu(DBM)(3)) coordinated P(MMA-co-EIPPMMA)-co-P(NIPAAm-co-NDAPM) copolymer was synthesized, which exhibited good biocompatibility and emitted strong red luminescence (MMA, methyl methacrylate; EIPPMMA, 4-(1-ethyl-1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)phenyl methacrylate; NIPAAm, N-isopropylacrylamide; NDAPM, (N-(3-dimethylamino)propyl)methacrylamide). The copolymer could self-assemble into micelles of size around 260 nm, and the micelles were thermosensitive at around body temperature. The drug-loaded micelles showed thermosensitive controlled drug release, and the paclitaxel loaded micelles were capable of being internalized into the tumor cells (A549) and exhibited obvious inhibition to the growth of A549 cells. Importantly, in vivo study showed the self-assembled micelles of Eu(DBM)(3) coordinated P(MMA-co-EIPPMMA)-co-P(NIPAAm-co-NDAPM) copolymer uptaken by the larvae of zebrafish could be easily tracked and be eliminated from the body within several days.

Controlled synthesis of rod-like LiVMoO(6) nanocrystals for application in lithium-ion batteries.

This paper reports a newly developed method for the shape and size control of transition metal composite oxides, such as LiVMoO(6), to obtain significantly enhanced electrode properties for lithium-ion batteries. Rod-like LiVMoO(6) nanocrystals were synthesized through a designed route of partial reduction, self-assembly and re-oxidation. V(5+) and Mo(6+) ions were used with low-grade starting materials to get a mixed valence of V and Mo. It is believed that ion pairs of V(5+)/V(4+) or Mo(6+)/Mo(5+) in the resultant mixture play an important role in the formation of a template precursor by self-assembly during a rheological phase reaction, although further explanation is required. The electrochemical performance of the LiVMoO(6) obtained has been much improved due to the increased crystallinity and reduced particle size of this material. 176 mA h g(-1) and 166 mA h g(-1) capacity was delivered in the initial discharge with a reversible capacity retention of 94.8% and 95.3% after 100 cycles in the range of 3.6-1.80 V versus metallic Li at 1 and 3 C current rate, respectively.

Exploratory spatial data analysis for the identification of risk factors to birth defects.

BACKGROUND: Birth defects, which are the major cause of infant mortality and a leading cause of disability, refer to "Any anomaly, functional or structural, that presents in infancy or later in life and is caused by events preceding birth, whether inherited, or acquired (ICBDMS)". However, the risk factors associated with heredity and/or environment are very difficult to filter out accurately. This study selected an area with the highest ratio of neural-tube birth defect (NTBD) occurrences worldwide to identify the scale of environmental risk factors for birth defects using exploratory spatial data analysis methods. METHODS: By birth defect registers based on hospital records and investigation in villages, the number of birth defects cases within a four-year period was acquired and classified by organ system. The neural-tube birth defect ratio was calculated according to the number of births planned for each village in the study area, as the family planning policy is strictly adhered to in China. The Bayesian modeling method was used to estimate the ratio in order to remove the dependence of variance caused by different populations in each village. A recently developed statistical spatial method for detecting hotspots, Getis's 7, was used to detect the high-risk regions for neural-tube birth defects in the study area. RESULTS: After the Bayesian modeling method was used to calculate the ratio of neural-tube birth defects occurrences, Getis's statistics method was used in different distance scales. Two typical clustering phenomena were present in the study area. One was related to socioeconomic activities, and the other was related to soil type distributions. CONCLUSION: The fact that there were two typical hotspot clustering phenomena provides evidence that the risk for neural-tube birth defect exists on two different scales (a socioeconomic scale at 6.84 km and a soil type scale at 22.8 km) for the area studied. Although our study has limited spatial exploratory data for the analysis of the neural-tube birth defect occurrence ratio and for finding clues to risk factors, this result provides effective clues for further physical, chemical and even more molecular laboratory testing according to these two spatial scales.