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The grid-based Xin'anjiang model (GXM) has been widely applied to flood forecasting. However, when the model warm-up period is long and the amount of input data is large, the computational efficiency of the GXM is obviously low. Therefore, a GXM parallel algorithm based on grid flow direction division is proposed from the perspective of spatial parallelism, which realizes the parallel computing of the GXM by extracting the parallel routing sequence of the watershed grids. To solve data skew, a Directed Acyclic Graph (DAG) scheduling algorithm based on dynamic priority is proposed for task scheduling. The proposed GXM parallel algorithm is verified in the Qianhe River watershed of Shaanxi Province and the Tunxi watershed of Anhui Province. The results show that the GXM parallel algorithm based on grid flow direction division has good flood forecasting accuracy and higher computational efficiency than the traditional serial computing method. In addition, the DAG scheduling algorithm can effectively improve the parallel efficiency of the GXM. HIGHLIGHTS Proposing a parallel algorithm based on grid flow direction division, speeding up the computation of the GXM.; Accurate flood forecasting facilitates flood management and flood control scheduling.; DAG scheduling algorithm can effectively improve parallel efficiency.;

Abstract Background To investigate short-term choroidal structural and vascular changes after epiretinal membrane (ERM) surgery. Methods In this retrospective study, 65 patients with unilateral ERM underwent pars plana vitrectomy combined with cataract surgery and were examined one day before surgery and one week, one month, and three months after surgery. Choroidal thickness (CT) and choroidal vascular index (CVI) were evaluated using horizontal enhanced depth imaging optical coherence tomography (EDI-OCT) scans and were further calculated using semi-automatic algorithms using MATLAB R2017a. Results Preoperatively, CVI was higher in eyes with ERM (61.70 ± 5.17%) than in fellow eyes (59.99 ± 5.26%). CVI increased significantly at one week after surgery (62.14 ± 5.02%) and decreased at 1 and 3 months after surgery (60.76 ± 4.97% and 60.4 ± 4.83%, respectively). The change was pronounced in the nasal region (p

Heavy metal (loid) pollution poses a serious threat to the health and habitability of ecosystems worldwide. This study aims to investigate the concentration, pollution degree, pollution sources, and health risks of heavy metal (loid)s (HMs) in soil of Shanxi Province, China. The concentrations of Cu, Ni, Cd, Pb, Hg and As were measured by ICP-MS in 146 soil samples collected from agricultural land. The pollution degree and ecological risks of HMs were analyzed by variety of indexes, and the human health risks were assessed using the USEPA model. Results showed the average concentrations of Cu, Cd, Pb, Hg and As were 1.08, 1.15, 1.44, 1.50 and 1.25 times higher than the background values in the soil of investigated areas, respectively. The contamination factors revealed moderate pollution of Hg, Pb, As, Cd and Cu in the investigated areas, and the pollution load index indicated considerable contamination. The Nemerow index revealed low to severe contamination with HMs. The potential ecological risk of HMs indicates that Hg and Cd pose a moderate risk threat to the soil ecology. Coal mining was the primary sources of soil HMs identified by ACPS-MLR. Soil As (75.1%) and Ni (62.3%) were mainly derived from coal mining, Pb (73.1%) was from traffic emissions, and Hg (38.6%) originated from coal combustion. The health risks associated with these HMs due to soil exposure were within the acceptable levels for adults. The As concentration imposes the strongest effect based on the non-carcinogenic risk analysis in different exposed populations. In conclusion, the higher concentration of soil HMs moderately threatens soil ecology, but there was no significant human health risk found in the study. Furthermore, this study reveals the potential risk and sources of HMs in Shanxi Province, which is helpful for managing contaminated soil in the region.

The real-time derivation of the concentration, area, and velocity of river surface ice based on camera imagery is essential for predicting the potential risks related to ice blockages in water routes. The key lies in the continuous tracking and velocity measuring of river ice, and reliable ice motion detection is a prerequisite for the dynamic perception of tracking targets. Previous studies did not utilize motion tracking for measuring ice velocity, and particle image velocimetry and feature point matching were used. This study aimed to use deep learning methods to address the challenging problems of deriving the ice concentration, area, and velocity based on camera imagery, and the focus was on measuring the ice velocity and drawing trajectories using the particle video tracking algorithm. We built a dataset named IPC_RI_IDS and collected information during the ice cover break-up process in the Nenjiang River (China). Our suggested approach was divided into four steps: (1) image preprocessing, where the camera image was calibrated to real-world coordinates; (2) determining the ice and water pixels in the camera image using the lightweight semantic segmentation network and then calculating the ice concentration and area; (3) enhancing and optimizing motion detection using the semantic segmentation results; and (4) adapting the particle video tracking algorithm to measure ice velocity using the proposed tracking points generation strategy. Finally, we analyzed the surface ice data in the study area and attempted to predict the stage of the ice break-up process to provide support for the real-time short-term forecasts of ice floods.

Precipitation images play an important role in meteorological forecasting and flood forecasting, but how to characterize precipitation images and conduct rainfall similarity analysis is challenging and meaningful work. This paper proposes a rainfall similarity research method based on deep learning by using precipitation images. The algorithm first extracts regional precipitation, precipitation distribution, and precipitation center of the precipitation images and defines the similarity measures, respectively. Additionally, an ensemble weighting method of Normalized Discounted Cumulative Gain-Improved Particle Swarm Optimization (NDCG-IPSO) is proposed to weigh and fuse the three extracted features as the similarity measure of the precipitation image. During the experiment on similarity search for daily precipitation images in the Jialing River basin, the NDCG@10 of the search results reached 0.964, surpassing other methods. This indicates that the method proposed in this paper can better characterize the spatiotemporal characteristics of the precipitation image, thereby discovering similar rainfall processes and providing new ideas for hydrological forecasting.

Zika virus (ZIKV) is a mosquito-borne flavivirus and can cause neurodevelopmental disorders in fetus. As a neurotropic virus, ZIKV persistently infects neural tissues during pregnancy but the viral pathogenesis remains largely unknown. ZIKV has a positive-sense and single-stranded RNA genome, which encodes 7 non-structural (NS) proteins, participating in viral replication and dysregulation of host immunity. Like those in many other viruses, NS proteins are considered to be products evolutionarily beneficiary to viruses and some are virulence factors. However, we found that some NS proteins encoded by ZIKV genome appeared to function against the viral replication. In this report we showed that exogenously expressed ZIKV NS2A and NS4A inhibited ZIKV infection by inhibiting viral RNA replication in microglial cells and astrocytes. To understand how viral NS proteins suppressed viral replication, we analyzed the transcriptome of the microglial cells and astrocytes and found that expression of NS4A induced the upregulation of ISGs, including MX1/2, OAS1/2/3, IFITM1, IFIT1, IFI6, IFI27, ISG15 or BST2 through activating the ISGF3 signaling pathway. Upregulation of these ISGs seemed to be related to the inhibition of ZIKV replication, since the anti-ZIKV function of NS4A was partially attenuated when the cells were treated with Abrocitinib, an inhibitor of the ISGF3 signaling pathway, or were knocked down with STAT2. Aborting the protein expression of NS4A, but not its nucleic acid, eliminated the antiviral activity of NS4A effectively. Dynamic expression of viral NS proteins was examined in ZIKV-infected microglial cells and astrocytes, which showed comparatively NS4A occurred later than other NS proteins during the infection. We hypothesize that NS4A may possess intrinsic features to serve as a unique type of pathogen associated molecular pattern (PAMP), detectable by the cells to induce an innate immune response, or function with other mechanisms, to restrict the viral replication to a certain level as a negative feedback, which may help ZIKV maintain its persistent infection in fetal neural tissues.

Zika virus (ZIKV) is a positive-sense RNA flavivirus and can cause serious neurological disorders including microcephaly in infected fetuses. As a mosquito-borne arbovirus, it enters the bloodstream and replicates in various organs. During pregnancy, it can be transmitted from the blood of the viremic mother to the fetus by crossing the placental barrier. Monocytes and macrophages are considered the earliest blood cell types to be infected by ZIKV. As a first line defense, these cells are crucial components in innate immunity and host responses and may impact viral pathogenesis in humans. Previous studies have shown that ZIKV infection can activate inflammasomes and induce proinflammatory cytokines in monocytes. In this report, we showed that ZIKV could infect and induce cell death in human and murine macrophages. In addition to the presence of cleaved caspase-3, indicating that apoptosis was involved, we identified the cleaved caspase-1 and gasdermin D (GSDMD) as well as increased secretion of IL-1β and IL-18. This suggests that the inflammasome was activated and that may lead to pyroptosis in infected macrophages. The pyroptosis was NLRP3-dependent and could be suppressed in the macrophages treated with shRNA to target and knockdown caspase-1. It was also be inhibited by an inhibitor for caspase-1, indicating that the pyroptosis was triggered via a canonical approach. Our findings in this study demonstrate a concomitant occurrence of apoptosis and pyroptosis in ZIKV-infected macrophages, with two mechanisms involved in the cell death, which may have potentially significant impacts on viral pathogenesis in humans.

The accurate and timely estimation of river discharge plays an important role in hydrological modeling, especially for avoiding the consequences of flood events. The majority of existing work on hydrologic prediction focuses on modeling the inherent physical process for specific river basins, while the geographic-connections between rivers are largely ignored. Geographically connected rivers provide rich spatial information that can be used to predict discharge amounts. In this paper, we study a novel problem of exploiting both temporal patterns and spatial connections for hydrological prediction. We construct three relationship graphs for hydrological gauges in the study area: the hydraulic distance graph, the Euclidean distance graph and the correlation graph. We fuse these graphs into one hydrological network graph, and propose a novel framework ST-Hydro which exploits Graph Convolutional Networks (GCN) for learning the spatial feature representations, and Recurrent Neural Networks with carefully designed activation functions for capturing temporal features simultaneously for hydrological prediction. Experimental results on real world data set demonstrate that the proposed framework can predict the river discharge effectively and at an early stage.

A wideband three-dimensional (3D) absorber based on a notch-slot resonator is proposed in this paper. A lossy coupled microstrip line was applied to eliminate the reflection band of the original lossy notch-slot resonator, resulting in a wide absorption band. A single-polarized design was first proposed, and the operating principle was demonstrated. Then, a dual-polarized design was presented, fabricated and measured. To eliminate the undesirable resonances caused by the securing slits cut between the two adjacent unit cells, some shorting pins were introduced. The measured results show that the dual-polarized absorber exhibits an absorption band from 2.74 GHz to 11.08 GHz (120.69% fractional bandwidth), and it is also stable under the incident angles up to 40° for both TE and TM polarizations.

Abstract We consider the following inequality: μ(L)n−kn≤CkmaxH∈Grn−kμ(L∩H), $$\begin{aligned} \mu (L)^{\frac{n-k}{n}} \leq C^{k}\max_{H\in \mathit{Gr}_{n-k}}\mu (L \cap H), \end{aligned}$$ which is a variant of the notable slicing inequality in convex geometry, where L is an origin-symmetric star body in Rn ${{\mathbb{R}}}^{n}$ and is μ-measurable, μ is a nonnegative measure on Rn ${\mathbb{R}} ^{n}$, Grn−k $\mathit{Gr}_{n-k}$ is the Grassmanian of an n−k $n-k$-dimensional subspaces of Rn ${\mathbb{R}}^{n}$, and C is a constant. By constructing the generalized k-intersection body with respect to μ, we get some results on this inequality.

This study develops a differential‐fed filtering patch antenna, which features superior frequency selectivity, compact size, low cross‐polarisation, and symmetrical radiation patterns. The proposed antenna consists of a rectangular patch on the top layer, which is differentially fed by a balun bandpass filter on the bottom layer. A pair of rectangular coupling slots were etched on the middle layer for energy coupling. The patch antenna performs not only as the radiator but also as the last resonator of the whole filter circuit for compactness. A prototype of the proposed filtering antenna operating at 2.45 GHz was fabricated and tested. The measured in‐band peak gain is 5.9 dBi with steep roll‐off at band edges, and the out‐of‐band gain is less than − 25 dBi. Moreover, symmetrical radiation patterns and low cross‐polarisation levels of − 22 dB are also realised for the proposed filtering antenna.

This paper presents a 3D band-absorptive frequency selective rasorber (FSR). Such an FSR is absorptive within a specific band and almost transparent below the absorption band. The definition and evaluation of the band-absorptive FSR is initially provided and followed by the design concept of 3D FSR. An example is then proposed, whose unit cell is composed of 3D absorber and 3D band-stop FSS. An equivalent circuit model is established for understanding its operating principle. A prototype of the proposed 3D band-absorptive FSR is fabricated. The measured results show that it has an absorption band ( $\vert S_{11}\vert \le -10$ dB and $\vert S_{21}\vert \le -10$ dB) from 4.21 to 6.51 GHz, with a thickness of 0.17 wavelength at 4.21 GHz. Moreover, $\vert S_{21}\vert $ is higher than −1 dB at the frequencies below 1.28 GHz. The proposed band-absorptive FSR can be used as radomes for low-frequency antennas in military communications or spectrum monitoring systems.

Apoptosis, pyroptosis and necroptosis are regulated processes of cell death which can be crucial for viral disease outcomes in hosts because of their effects on viral pathogenicity and host resistance. Zika virus (ZIKV) is a mosquito-borne flavivirus, which infects humans and can cause neurological disorders. Neural developmental disorders and microcephaly could occur in infected fetuses. Several types of nervous cells have been reported to be susceptible to ZIKV infection. Human astrocytes play important roles in the nutritional support and defense of neurons. In this study, we show that human astrocytes are susceptible to ZIKV infection and undergo progressive cell death after infection. In infected astrocytes we detected no cleavage or activation of pro-caspase-3 and pro-caspase-1. Apoptotic substrates and increased secretion of interleukin (IL)-1β or IL-18 were not detected, either. These ruled out the occurrence of apoptosis or pyroptosis in ZIKV-infected astrocytes. We detected, however, an increase of phosphorylated receptor-interacting serine/threonine-protein kinase (RIPK)1, RIPK3, and mixed lineage kinase domain-like (MLKL) protein, indicating that programmed necrosis, or necroptosis, was induced in infected astrocytes. The phosphorylation and cell death were inhibited in cells pre-treated with GSK’872, an inhibitor of RIPK3, while inhibition of RIPK1 with an inhibitor, Necrostatin-1, had no effect, suggesting that ZIKV-induced necroptosis was RIPK1-independent in astrocytes. Consistent with this finding, the inhibition of RIPK1 had no effect on the phosphorylation of MLKL. We showed evidence that MLKL phosphorylation was RIPK3-dependent and ZBP-1, which could stimulate RIPK3, was upregulated in ZIKV-infected astrocytes. Finally, we demonstrated that in GSK’872-pre-treated astrocytes, viral replication increased significantly, which indicates that necroptosis may be protective against viral replication in astrocytes. Our finding that astrocytes uniquely underwent necroptosis in response to ZIKV infection provides insight and helps us better understand the viral pathogenesis in the ZIKV-infected central nervous system.

Drought is a severe abiotic stress that imposes a serious threat to rice productivity. Although previous studies have found that melatonin can promote seed germination, the physiological regulation mechanism of drought tolerance in rice seed germination mediated by exogenous melatonin is still unclear. In order to overcome these challenges, polyethylene glycol 6000 (PEG6000) at concentrations of 20% and 35% was used to simulate osmotic stress. Rice seeds were treated with different concentrations of melatonin (i.e., 0, 20, 100, and 500 μM) to study the effects on germination characteristics, growth and development, superoxide dismutase (SOD) activity, peroxidase (POD) activity, catalase (CAT) activity, malondialdehyde (MDA) content, and soluble protein content. The results showed that the seed soaking treatment using melatonin at a concentration of 100 μM under drought stress effectively promoted the germination rate and improved the biomass of rice seed shoots and roots. Meanwhile, this treatment reduced MDA content to alleviate the oxidative damage of rice seeds caused by drought stress. The two-way ANOVA showed that the effect of single melatonin soaking treatment on rice seed germination was more significant than that of single drought stress and the interaction of drought stress and melatonin (p < 0.05). Using the membership function method, it was shown that the critical gradient of rice seeds under drought stress was 35%, and the critical treatment of interactive treatment was 35% + 100 μM. Through grey correlation analysis, it was found that germination rate (7 d) had the highest grey correlation with melatonin seed soaking treatment to evaluate the mitigation effect of melatonin on drought stress. This study provides a theoretical basis for light and simple cultivation technology for the dry direct seeding of rice.

High temperatures are a major concern that limit rice germination and plant growth. Although previous studies found that melatonin can promote seed germination, the physiological regulation mechanism by which exogenous melatonin mediates high temperature tolerance during rice seed germination is still largely unknown. In order to overcome these challenges, the present study investigates the effects of melatonin on the characteristics of rice seed germination as well as on antioxidant properties, under different high temperature conditions. The results show that 100 μM melatonin seed-soaking treatment under high temperature conditions effectively improves the germination potential, the germination index, and the vigor index of rice seeds; increases the length of the shoot and the root; improves the activity of the antioxidant enzymes; and significantly reduces the malondialdehyde content. The gray relational grade of the shoot peroxidase activity and the melatonin soaking treatment was the highest, which was used to evaluate the effect of melatonin on the heat tolerance of rice. The subordinate function method was used to comprehensively evaluate the tolerance, and the results show that the critical concentration of melatonin is 100 μM, and the critical interactive treatment is the germination at 38 °C and followed by the recovery at 26 °C for 1 day + 100 μM. In conclusion, 100 μM of melatonin concentration improved the heat resistance of rice seeds by enhancing the activity of the antioxidant enzymes.

Discriminative correlation filters (DCFs) have been widely used in visual object tracking, but often suffer from two problems: the boundary effect and temporal filtering degradation. To deal with these issues, many DCF-based variants have been proposed and have improved the accuracy of visual object tracking. However, these trackers only adopt first-order data-fitting information and have difficulty maintaining robust tracking in unconstrained scenarios, especially in the case of complex appearance variations. In this paper, by introducing a second-order data-fitting term to the DCF, we propose a second-order spatial–temporal correlation filter (SSCF) learning model. To be specific, the SSCF tracker both incorporates the first-order and second-order data-fitting terms into the DCF framework and makes the learned correlation filter more discriminative. Meanwhile, the spatial–temporal regularization was integrated to develop a robust model in tracking with complex appearance variations. Extensive experiments were conducted on the benchmarking databases CVPR2013, OTB100, DTB70, UAV123, and UAVDT-M. The results demonstrated that our SSCF can achieve competitive performance compared to the state-of-the-art trackers. When penalty parameter λ was set to 10−5, our SSCF gained DP scores of 0.882, 0.868, 0.706, 0.676, and 0.928 on the CVPR2013, OTB100, DTB70, UAV123, and UAVDT-M databases, respectively.

This paper presents a 3D absorptive frequency-selective reflection structure (AFSR) and absorptive frequency-selective transmission structure (AFST) with one reflection/transmission band and two absorption bands. The 3D AFSR utilizes the intrinsic reflection band and higher order absorption band of a wideband 3D absorber. By simply loading a printed gap capacitor in the structure, the reflection band can be easily tuned by varying the capacitance of the capacitor. A design example is presented, with a reflection band of 24.7% fractional bandwidth (FBW), a lower absorption band of 72.5% FBW, and a higher absorption band of 48.6% FBW. A 3D AFST composed of the 3D AFSR and a parallel-plate waveguide is then proposed. Its general operating principle is demonstrated, such that the 3D AFST can be seen as a combination of a 3D AFSR and a 3D band-pass FSS, which can independently contribute to the absorption and transmission, respectively. A set of guidelines is proposed to facilitate the design. A prototype of the proposed AFST is fabricated and measured. The measured results show that the transmission band is with a minimum insertion loss of 0.4 dB and an FBW of 30%. Moreover, the lower and higher absorption bands are with 63.9 % and 47.6 % FBW, respectively. The proposed AFST has a simpler structure, wider lower absorption bandwidth, and thinner thickness compared with previous structures.

Viral infections are one of the leading causes in human mortality and disease. Broad-spectrum antiviral drugs are a powerful weapon against new and re-emerging viruses. However, viral resistance to existing broad-spectrum antivirals remains a challenge, which demands development of new broad-spectrum therapeutics. In this report, we showed that fludarabine, a fluorinated purine analogue, effectively inhibited infection of RNA viruses, including Zika virus, Severe fever with thrombocytopenia syndrome virus, and Enterovirus A71, with all IC50 values below 1 μM in Vero, BHK21, U251 MG, and HMC3 cells. We observed that fludarabine has shown cytotoxicity to these cells only at high doses indicating it could be safe for future clinical use if approved. In conclusion, this study suggests that fludarabine could be developed as a potential broad-spectrum anti-RNA virus therapeutic agent.

Zika virus (ZIKV) has spread rapidly in recent years and there is a need for antiviral treatments. Here, the authors develop an antiviral peptide, based on the stem region of ZIKV envelope protein, and show that it is safe in pregnant mice and inhibits ZIKV infection in pregnant mice and fetuses.

Emerging Microbes & Infections (2017) 6, e102; doi:10.1038/emi.2017.90; published online 29 November 2017

Simple and low cost tag antenna with long reading distance in various environments is in great demand with its wide applications. This paper describes the design and optimization procedure of a single-layer tag antenna, which covers relatively long reading range when mounted on both metallic surface and various dielectrics. The antenna is based on the loop structure, with a small ka of 0.66. Characteristic mode analysis is first performed to inspect how a typical loop structure radiates in free space and on PEC. Antenna structure is then designed based on the characteristics of the loop. Afterward, equivalent circuits of the tag antenna on dielectrics and on metal are extracted, in order to provide guidance for antenna optimization. The proposed tag antenna achieves the maximum reading distance of 6.1 m and 14.1 m, respectively, when mounted on metal and dielectrics with low permittivity. Measurements of the tag antenna were carried out in different environments, including outdoor scenario, indoor scenarios with low and high reflections. The measured results agree reasonably well with the predicted ones. The tag antenna is proved to be competitive in perspective of simple structure, low cost, long reading distance, and tolerance on various background materials.

Anomalous patterns are common phenomena in time series datasets. The presence of anomalous patterns in hydrological data may represent some anomalous hydrometeorological events that are significantly different from others and induce a bias in the decision-making process related to design, operation and management of water resources. Hence, it is necessary to extract those “anomalous” knowledge that can provide valuable and useful information for future hydrological analysis and forecasting from hydrological data. This paper focuses on the problem of detecting anomalous patterns from hydrological time series data, and proposes an effective and accurate anomalous pattern detection approach, TFSAX_wPST, which combines the advantages of the Trend Feature Symbolic Aggregate approximation (TFSAX) and weighted Probabilistic Suffix Tree (wPST). Experiments with different hydrological real-world time series are reported, and the results indicate that the proposed methods are fast and can correctly detect anomalous patterns for hydrological time series analysis, and thus promote the deep analysis and continuous utilization of hydrological time series data.

Similarity analysis of small- and medium-sized watersheds mainly depends on manual work, and there is no complete automated analysis method. In order to solve this problem, we propose a similarity analysis method based on clustering ensemble model. First, the iterative clustering ensemble construction algorithm with weighted random sampling (WRS-CCE) is proposed to get great clustering collectives. Then, we combine spectral clustering with the fuzzy C-means method to design a consensus function for small- and medium-sized watershed data sets. Finally, the similarity analysis of small- and medium-sized watersheds is carried out according to the clustering results. Experiments show that the proposed clustering ensemble model can effectively find more potential similar watersheds and can output the similarity of these watersheds.

Ensuring the quality of hydrological data has become a key issue in the field of hydrology. Based on the characteristics of hydrological data, this paper proposes a data-driven quality control method for hydrological data. For continuous hydrological time series data, two combined forecasting models and one statistical control model are constructed from horizontal, vertical, and statistical perspectives and the three models provide three confidence intervals. Set the suspicious level based on the number of confidence intervals for data violations, control the data, and provide suggested values for suspicious and missing data. For the discrete hydrological data with large time-space difference, the similar weight topological map between the neighboring stations is established centering on the hydrological station under the test and it is adjusted continuously with the seasonal changes. Lastly, a spatial interpolation model is established to detect the data. The experimental results show that the quality control method proposed in this paper can effectively detect and control the data, find suspicious and erroneous data, and provide suggested values.