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The information of fractures in rock mass is an essential indicator to evaluate the quality of rock mass. It is precise and efficient to obtain information of fractures by computer vision (CV)-based fracture detection technologies. However, rock masses in practical engineering always exhibit complex fractures with messy edges, shadows, and uneven rock surfaces. These factors negatively impact the effectiveness of fracture detection algorithms. To address such issues, this paper proposes a confidence score-based rock fracture detection algorithm that can effectively identify fractures in complex situations. The image with fractures is traversed to acquire candidate points at first. We proposed a method to evaluate the confidence scores of these candidate points according to the values of Hessian matrix eigenvalues, the degree of symmetry, and the gray-scale value. The candidate points are further filtered through threshold restriction and non-maximum suppression. Furthermore, the complete centerlines of the fractures are obtained by the connection of the candidate points and the connection of discontinuous centerlines. Finally, pseudo-fractures and noise are eliminated to get complete fractures. Experimental results show that the newly proposed algorithm can accurately identify fractures in complex situations. The algorithm avoids interference and noise, which achieves more precise results than other conventional fracture detection algorithms, is an effective method to identify fractures in rocky geological engineering and can also serve as a guide for other relevant fracture identification algorithm in rock mass. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau, as a major elevated heat source, plays a critical role in the Asian monsoon and global climate. Observational data revealed significant correlations between spring surface air temperature in the Tibetan Plateau and downstream summer precipitation interannual variations. Sensitivity experiments using the regional Climate-Weather Research and Forecasting model (CWRF) were conducted to understand the physical processes and mechanisms underlying such delayed teleconnections. A positive temperature forcing was imposed over the plateau on the surface and subsurface soil layers only at the initial conditions around May 1st, 2003. This regional forcing quickly induces positive perturbations in local air temperature and, more importantly, maintains its signal in local soil, especially deep layers, for several months. Consequently, the soil temperature serves as a charged capacitor to modulate the planetary atmospheric circulation and through Rossby wave chains to cause significant summer precipitation anomalies over broad regions. This relayed teleconnection pattern is consistent with that identified from observational data records and CWRF climate simulations during 1980–2015. Diagnostic analyses of observations and simulations suggest that the Tibetan Plateau heating significantly impacts summer East Asian monsoon climate through influencing the South Asian High and shifting the East Asian jet. [ABSTRACT FROM AUTHOR]

Results from eight regional climate models (RCMs) participating in the Impact of Initialized Land Temperature and Snowpack on Sub-seasonal to Seasonal Prediction (LS4P) initiative of the Global Energy and Water Exchanges (GEWEX) are examined and compared with observations over the Tibetan Plateau (TP). The RCM common domain covers most areas of East Asia with a horizontal resolution of 20–30 km. The model simulation covers a period from April to September in each year between 1991 and 2015. This study explores the RCMs' ability for seasonal climate simulation over the TP, focusing on the summer monsoon climate as part of the LS4P initiative. An intercomparison is made among eight RCMs for precipitation, surface air temperature, mid-troposphere atmospheric circulation, moisture conditions, and surface energy fluxes. It shows that the downscaling characteristics differ significantly between two major RCM types. The RegCM4 models show positive precipitation biases over the entire TP, especially over the south and southeast TP, while the WRF models mostly show both positive and negative precipitation biases over the TP with relatively high spatial correlation between simulated and observed precipitation. The multi-model ensemble mean produces overall smaller precipitation biases than most individual RCMs, with the largest biases over the southeastern TP, and smaller surface air temperature biases over most areas of the TP, especially over the central and southwestern TP. Moreover, the ensemble mean can better reproduce the inter-annual variation of precipitation and surface air temperature than most RCMs with proper magnitude. Sensitivity analyses using RegCM4 with different physics parameterizations show that varying land and cumulus schemes may induce large precipitation differences over the TP by affecting moisture and atmospheric circulation conditions in the lower and upper troposphere, respectively. Moreover, turbulent heat and radiation fluxes differences are associated with the temperature differences between different RegCM4 models. [ABSTRACT FROM AUTHOR]

Ranging from subcellular organelle biogenesis to embryo development, the formation of self-organized structures is a hallmark of living systems. Whereas the emergence of ordered spatial patterns in biology is often driven by intricate chemical signalling that coordinates cellular behaviour and differentiation1–4, purely physical interactions can drive the formation of regular biological patterns such as crystalline vortex arrays in suspensions of spermatozoa5 and bacteria6. Here we discovered a new route to self-organized pattern formation driven by physical interactions, which creates large-scale regular spatial structures with multiscale ordering. Specifically we found that dense bacterial living matter spontaneously developed a lattice of mesoscale, fast-spinning vortices; these vortices each consisted of around 104–105 motile bacterial cells and were arranged in space at greater than centimetre scale and with apparent hexagonal order, whereas individual cells in the vortices moved in coordinated directions with strong polar and vortical order. Single-cell tracking and numerical simulations suggest that the phenomenon is enabled by self-enhanced mobility in the system—that is, the speed of individual cells increasing with cell-generated collective stresses at a given cell density. Stress-induced mobility enhancement and fluidization is prevalent in dense living matter at various scales of length7–9. Our findings demonstrate that self-enhanced mobility offers a simple physical mechanism for pattern formation in living systems and, more generally, in other active matter systems10 near the boundary of fluid- and solid-like behaviours11–17.We demonstrate that self-enhanced mobility offers a simple physical mechanism for pattern formation in living systems and, more generally, in other active matter systems near the boundary of fluid- and solid-like behaviours. [ABSTRACT FROM AUTHOR]

Spinel Li2ZnTi3O8 (LZTO) with a zero volumetric change, exhibits high safety as an anode of lithium-ion batteries. Nevertheless, the low electrical conductivity restricts its wide application. A facile one-step solid-state route has been used to synthesize LZTO@C-N composites with different N content. The existence of N-doped carbon improves the diffusion coefficients of Li+ ions and the electronic conductivity, and reduces the charge-transfer resistance and the side reactions between electrolyte and LZTO. The N content can affect the lattice constants and the appearance the new phases. The LZTO@C-N-2 composite with the proper N content of 2.2 w.% possesses the best electrochemical performance in wide temperature range from 0 to 55 °C. Discharging at 2 A g−1 and charging at 0.5 A g−1, 219.7 and 214.8 mAh g−1 are obtained for LZTO@C-N-2 at the 1st and 150th cycles, respectively, with small capacity fade at 25 °C. 290.3 and 151 mAh g−1 are delivered at the 1st and 150th cycles for LZTO@C-N-2 at 55 °C, respectively. Even at 0 °C, the LZTO@C-N-2 composite still shows good rate capability. The simple synthetic route and good electrochemical performance enable LZTO@C-N-2 to be a potential anode of LIBs. [ABSTRACT FROM AUTHOR]

In this paper, the simultaneous resonance of a ferromagnetic thin plate in a time-varying magnetic field, having axial speed and being subjected to a periodic line load, is studied. Based on the large deflection theory of thin plates and electromagnetic field theory, the nonlinear vibration differential equation of the plate is obtained by using the Hamilton's principle and the Galerkin method. Then the boundary condition in which the longer opposite sides are clamped and hinged is considered. The dimensionless nonlinear differential equations are solved by using the method of multiple scales, and the analytical solution is given. In addition, the stability analysis is also carried out by using Lyapunov stability theory. Through numerical analysis, the variation curves of system resonance amplitude with frequency tuning parameter, magnetic field strength and external excitation amplitude are obtained. Different parameters that have significant effects on the response of the system, such as the thickness, the axial velocity, the magnetic field intensity, the position, and the frequency of external excitation, are considered and analyzed. The results show that the system has multiple solution regions and obvious nonlinear coupled characteristics. [ABSTRACT FROM AUTHOR]

Estimating the health burden of air pollution against the background of population aging is of great significance for achieving the Sustainable Development Goal 3.9 which aims to substantially reduce the deaths and illnesses from air pollution. Here, we estimated spatiotemporal changes in deaths attributable to PM2.5 air pollution in China from 2000 to 2035 and examined the drivers. The results show that from 2019 to 2035, deaths were projected to decease 15.4% (6.6%–20.7%, 95% CI) and 8.4% (0.6%–13.5%) under the SSP1-2.6 and SSP5-8.5 scenario, respectively, but increase 10.4% (5.1%–20.5%) and 18.1% (13.0%–28.3%) under SSP2-4.5 and SSP3-7.0 scenarios. Population aging will be the leading contributor to increased deaths attributable to PM2.5 air pollution, which will counter the positive gains achieved by improvements in air pollution and healthcare. Region-specific measures are required to mitigate the health burden of air pollution and this requires long-term efforts and mutual cooperation among regions in China. Estimating health burden of air pollution against the background of population aging is of significance for achieving Sustainable Development Goal 3.9. Here, the authors show that population aging is expected to be the leading contributor to increased deaths attributable to PM2.5 in China by 2035, which will counter the positive gains achieved by improvements in air pollution and healthcare. [ABSTRACT FROM AUTHOR]

Haloacid dehalogenase-like hydrolase (HAD) superfamily have been shown to get involved in plant growth and abiotic stress response. Although the various functions and regulatory mechanism of HAD superfamily have been well demonstrated, we know little about the function of this family in conferring abiotic stress tolerance to rice. Here, we report OsHAD3, a HAD superfamily member, could affect drought tolerance of rice. Under drought stress, overexpression of OsHAD3 increases the accumulation of reactive oxygen species and malondialdehyde than wild type. OsHAD3-overexpression lines decreased but antisense-expression lines increased the roots length under drought stress and the transcription levels of many well-known stress-related genes were also changed in plants with different genotypes. Furthermore, overexpression of OsHAD3 also decreases the oxidative tolerance. Our results suggest that overexpression of OsHAD3 could decrease the drought tolerance of rice and provide a new strategy for improving drought tolerance in rice. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the consensus problem of multi-agent systems (MASs) with a limited sensing range using two kinds of distributed neighbor selection strategies. Because each agent's convergence evolution is typically based on the "select all perceived neighbors" (SAN) framework, fragmentation into multiple clusters is likely to occur, and data storage and computational load can grow exponentially as the number of agents increases. To address this challenge, we propose a new distributed consensus framework composed of two strategies that can effectively enhance the consensus of the MAS. First, a novel representative selection with rotating-segmentation perception (RSRSP) strategy is provided for agents to intelligently select representative neighbors in each sector of the communication region for convergence evolution. Second, a distributed switching strategy is designed for each agent to synchronously switch from RSRSP to SAN when the system reaches full connectivity. We analyze the stability of the proposed consensus protocol with the common Lyapunov function and verify the superiority of the two proposed strategies through comparisons with a baseline SAN algorithm. [ABSTRACT FROM AUTHOR]

Intervertebral disc degeneration (IDD) is closely related to inflammation and imbalance of synthesis/catabolism of extracellular matrix (ECM) in intervertebral disc (IVD). Considering this, luteolin (LUT), a kind of natural flavonoid with good anti-inflammatory effect and TGF-β1 (a gene that promotes the regeneration of ECM) plasmid was co-loaded and co-delivered to nucleus pulposus cells (NPCs). Reactive oxygen species (ROS) responsive cationic copolymer, poly(β-amino ester)-poly(ε-caprolactone) (PBC), with high plasmid DNA (pDNA) compression affinity was synthesized. It can self-assemble into nano-sized polyplexes (pDNA@PBC) with virus-inspired structure and function through which it can transfect pDNA into NPCs with very high efficiency and negligible cytotoxicity. LUT was encapsulated in the hydrophobic core of pDNA@PBC. The co-delivery system, LUT-pTGF-β1@PBC, could enhance the cellular uptake of NPCs and manifest excellent sustained drug release in IVD. Real time quantitative polymerase chain reaction (RT-qPCR) and Western blot experiments reveal that the co-delivery system could inhibit inflammation in NPCs and restore the balance of anabolism and catabolism in vitro by activating TGF/SMAD3 and inhibiting NF-kB/p65. Moreover, LUT-pTGF-β1@PBC retards IDD in vivo as detected by radiological and histological methods with good biosafety in rats. LUT-pTGF-β1@PBC may be a promising option for the treatment of IDD. [ABSTRACT FROM AUTHOR]

Numerical reservoir modeling plays an important role in understanding and predicting the performance of geothermal reservoirs to varying exploitation schemes. In this study, four parameters including thermal breakthrough time, water level and vertical displacement at the production wells and the recoverable energy in the licensed region are selected to assess the potential exploitation schemes. An integrated model combining the simplified 1D geothermal well model and the 3D geothermal reservoir model is developed to simulate the fully coupled thermo-hydro-mechanical (THM) processes in geothermal reservoirs including multiple wells, and the measured surface settlement data in the Geysers geothermal field is used to validate the reasonability and efficiency of the developed modeling method. A case study of the Rongcheng geothermal field, China, is presented to clarify the important role of coupled THM processes in the sustainable exploitation of geothermal resources. The results show that the developed integrated model is a robust simulation tool to understand and predict the performance of city-scale geothermal fields under different patterns of well groups. The production wells may not reach the designed lifetime due to various natural or artificial reasons, so the optimal well patterns should be designed to maximize the recoverable geothermal energy considering the natural properties of geothermal reservoirs. Highlights: Coupled thermo-hydro-mechanical processes are considered in an integrated geothermal reservoir model. Assessment criteria of sustainable exploitation of geothermal resources in the licensed region are defined. The responses of the Rongcheng geothermal field under different patterns of well groups are studied. [ABSTRACT FROM AUTHOR]

The nonaxisymmetric magnetoelastic nonlinear coupling free vibration study is performed for a conductive thin annular plate in the nonuniform toroidal magnetic field generated by a long straight current carrying wire in this article. From the electromagnetic theory, expressions for the magnetic field, electromagnetic force and torque acting on the plate are deduced. According to Hamilton principle, nonaxisymmetric magnetoelastic nonlinear vibration equation is derived. The displacement functions for plate under three different boundary conditions are solved, which is combined with Galerkin integral method for derivation of nondimensional coupling nonlinear differential equations. The method of multiple scales is introduced to solve the coupling equations and achieve the second-approximation analytical solution, and then, expressions for the first three mode nondimensional natural frequencies of plate are obtained. In numerical examples, diagrams of electromagnetic characteristics and the first three frequencies under magnetic field and modal coupling effect are presented, which shows the influence of different parameters, e.g., current intensity, plate size and time on natural frequencies and electromagnetic forces. The variation of system singularity stability is discussed, and the obtained analytical results are also validated. The results indicate that current, plate size and time parameters have obvious influence on natural frequencies, which also shows quite different variations under different boundaries. Additionally, initial conditions have significant effects on natural frequencies, which becomes more complicated under modal coupling effect. In nonaxisymmetric vibration case, electromagnetic forces show complicated changing rules along radial and circumferential directions. Furthermore, system equilibrium point will be changed by the induced nonuniform magnetic field. [ABSTRACT FROM AUTHOR]

Investigation into natural fractures is extremely important for the exploration and development of low-permeability reservoirs. Previous studies have proven that abundant oil resources are present in the Upper Triassic Yanchang Formation Chang 7 oil-bearing layer of the Ordos Basin, which are accumulated in typical low-permeability shale reservoirs. Natural fractures are important storage spaces and flow pathways for shale oil. In this study, characteristics of natural fractures in the Chang 7 oil-bearing layer are first analyzed. The results indicate that most fractures are shear fractures in the Heshui region, which are characterized by high-angle, unfilled, and ENE-WSW-trending strike. Subsequently, natural fracture distributions in the Yanchang Formation Chang 7 oil-bearing layer of the study area are predicted based on the R/S analysis approach. Logs of AC, CAL, ILD, LL8, and DEN are selected and used for fracture prediction in this study, and the R(n)/S(n) curves of each log are calculated. The quadratic derivatives are calculated to identify the concave points in the R(n)/S(n) curve, indicating the location where natural fracture develops. Considering the difference in sensitivity of each log to natural fracture, gray prediction analysis is used to construct a new parameter, fracture prediction indicator K, to quantitatively predict fracture development. In addition, fracture development among different wells is compared. The results show that parameter K responds well to fracture development. Some minor errors may probably be caused by the heterogeneity of the reservoir, limitation of core range and fracture size, dip angle, filling minerals, etc. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 is of zoonotic origin and contains a PRRA polybasic cleavage motif which is considered critical for efficient infection and transmission in humans. We previously reported on a panel of attenuated SARS-CoV-2 variants with deletions at the S1/S2 junction of the spike protein. Here, we characterize pathogenicity, immunogenicity, and protective ability of a further cell-adapted SARS-CoV-2 variant, Ca-DelMut, in in vitro and in vivo systems. Ca-DelMut replicates more efficiently than wild type or parental virus in Vero E6 cells, but causes no apparent disease in hamsters, despite replicating in respiratory tissues. Unlike wild type virus, Ca-DelMut causes no obvious pathological changes and does not induce elevation of proinflammatory cytokines, but still triggers a strong neutralizing antibody and T cell response in hamsters and mice. Ca-DelMut immunized hamsters challenged with wild type SARS-CoV-2 are fully protected, with little sign of virus replication in the upper or lower respiratory tract, demonstrating sterilizing immunity. The S1/S2 junction of the SARS-CoV-2 Spike protein is emerging as a key factor in virulence and pathogenesis. Here, the authors characterise an attenuated strain of SARS-CoV-2 with deletions in the critical S1/S2 junction and observe enhanced replication, generation of potent adaptive immunity but reduced immunopathology in a hamster model of infection. [ABSTRACT FROM AUTHOR]

Stress sensitivity is the variation of rock petrophysical parameters resulting from changes in effective stress. In fractured reservoirs, experimental methods exhibit a certain amount of error in the quantitative analysis of reservoir rock stress sensitivity. In addition, fracture-bearing experimental rock samples are difficult to obtain and prepare. Therefore, in the present study, reservoir rock stress sensitivity in naturally fractured reservoirs was investigated based on geomechanical modeling using a case study of the Lower Cretaceous Xiagou Formation in the Qingxi Oilfield. The results indicate that the Xiagou fractured reservoir experiences strong stress sensitivity with a fracture permeability damage rate reaching 94.38%. Natural fractures influence reservoir rock stress sensitivity. The degree of filling and type of filled minerals within natural fractures have great effects on the permeability damage rate. A higher permeability damage rate suggests stronger rock stress sensitivity. Generally, I) for reservoir rocks with unfilled natural fractures, the permeability damage rate is extremely high; II) for reservoir rocks with partially filled natural fractures, the permeability damage rate is high, and if the minerals within the natural fractures are insoluble, the permeability damage rate is slightly higher than if the materials are soluble; III) for reservoir rocks with completely filled natural fractures, the permeability damage rate is extremely low if the minerals within the natural fractures are insoluble; however, if the materials are soluble, the permeability becomes slightly higher with the increase of effective stress. Most importantly, this study provides a practical method for analyzing stress sensitivity in naturally fractured reservoirs. [ABSTRACT FROM AUTHOR]

The effects of S and Se treatment on cabbage, especially the interactions of S and Se metabolism with the biosynthesis of glucosinolate (GSL), including glucoraphanin, which is a major aliphatic GSL in cruciferous vegetables and the precursor of the anticancer compound sulforaphane, were examined. Cabbage plants were treated with sulfate and selenite (SeO32−), and the total S, Se, and GSL contents of cabbage head and outer foliage leaves were measured. Results showed that selenite treatment was beneficial to GSL biosynthesis and Se accumulation in cabbage head and outer foliage leaves. GSL synthesis was induced by exogenous selenite-elevated sulfate treatment at certain concentration ratios, i.e., 50-μΜ selenite + 1-mΜ sulfate or 100-μΜ selenite + 4-mΜ sulfate. A high exogenous sulfate concentration was more favorable to GSL accumulation than a low sulfate concentration. According to the relative expression of genes on GSL synthesis, an increase in the GSL content was attributed to the upregulation of gene expression and possible transportation from the outer foliage leaf to the head of cabbage. These results might be helpful for increasing the health benefits of cabbage by supplying exogenous S and Se. Further research should explore the effects of sulfate and selenite on GSL precursor substances to reveal the reason why total GSL contents increased. [ABSTRACT FROM AUTHOR]

The effective viscosity (μeff) has a crucial turbulent effect in the fluid flow. In this work, μeff is proposed and applied to the Burton, Prim, and Slichter (BPS) and Ostrogorsky-Muller (OM) analytical models to estimate the solute boundary layer in Czochralski (CZ) growth of silicon. A series of numerical simulations for CZ silicon growth are performed, with different crystal rotation rates (ranging from 1 to 50 rpm), in order to obtain different convective flow regimes. The results revealed 3.6% as the average predicted error (where, μeff was employed as an input) for the boundary layer thickness between the modified models. Furthermore, the modified OM model was also verified to describe the radial distribution of solute boundary layer, and to demonstrate the capturing efficiency of the characteristic points at melt/crystal interface. Aiming at practical purposes, Gr/Re2 was proposed as a criterion to obtain the weak lateral segregation of impurities in the crystal growth process. [ABSTRACT FROM AUTHOR]

It is known that pre-existing discontinuities can act as planes of weakness that divert the propagating fractures in rocks, but previous studies have mostly focused on the interaction between the propagating fractures and a single pre-existing discontinuity. The influences of multiple pre-existing cemented discontinuities, such as calcite veins and bedding planes, on the fracture propagation still remain poorly understood. In this study, particle-based discrete element method was used to characterize the fracturing behavior of shale containing multiple cemented veins and bedding planes through numerical semi-circular bend (SCB) tests. Model results show that geometrical and mechanical properties of multiple pre-existing cemented discontinuities can significantly affect the interaction modes between the induced tensile fractures and pre-existing cemented discontinuities, as well as the mode I fracture toughness of shale. The typical mechanical interaction modes between the induced tensile fractures and the multiple pre-existing cemented discontinuities and the corresponding conditions are given. The effect of pre-coexisting discontinuities on the peak loads for shale during SCB tests is also discussed. [ABSTRACT FROM AUTHOR]

Nitrogen-use efficiency of indica varieties of rice is superior to that of japonica varieties. We apply 16S ribosomal RNA gene profiling to characterize root microbiota of 68 indica and 27 japonica varieties grown in the field. We find that indica and japonica recruit distinct root microbiota. Notably, indica-enriched bacterial taxa are more diverse, and contain more genera with nitrogen metabolism functions, than japonica-enriched taxa. Using genetic approaches, we provide evidence that NRT1.1B, a rice nitrate transporter and sensor, is associated with the recruitment of a large proportion of indica-enriched bacteria. Metagenomic sequencing reveals that the ammonification process is less abundant in the root microbiome of the nrt1.1b mutant. We isolated 1,079 pure bacterial isolates from indica and japonica roots and derived synthetic communities (SynComs). Inoculation of IR24, an indica variety, with an indica-enriched SynCom improved rice growth in organic nitrogen conditions compared with a japonica-enriched SynCom. The links between plant genotype and root microbiota membership established in this study will inform breeding strategies to improve nitrogen use in crops. Rice coordinates recruitment of the root microbiota to optimize nitrogen acquisition from soil. [ABSTRACT FROM AUTHOR]

Land plants in natural soil form intimate relationships with the diverse root bacterial microbiota. A growing body of evidence shows that these microbes are important for plant growth and health. Root microbiota composition has been widely studied in several model plants and crops; however, little is known about how root microbiota vary throughout the plant’s life cycle under field conditions. We performed longitudinal dense sampling in field trials to track the time-series shift of the root microbiota from two representative rice cultivars in two separate locations in China. We found that the rice root microbiota varied dramatically during the vegetative stages and stabilized from the beginning of the reproductive stage, after which the root microbiota underwent relatively minor changes until rice ripening. Notably, both rice genotype and geographical location influenced the patterns of root microbiota shift that occurred during plant growth. The relative abundance of Deltaproteobacteria in roots significantly increased overtime throughout the entire life cycle of rice, while that of Betaproteobacteria, Firmicutes, and Gammaproteobacteria decreased. By a machine learning approach, we identified biomarker taxa and established a model to correlate root microbiota with rice resident time in the field (e.g., Nitrospira accumulated from 5 weeks/tillering in field-grown rice). Our work provides insights into the process of rice root microbiota establishment. [ABSTRACT FROM AUTHOR]

How to mitigate stock price crash risk has become a focus in the theoretical and practical fields. Building on the work of Kim et al. (J Bank Finance, 43:1-13, 2014b), this paper investigates the relation between corporate philanthropy and crash risk under the unique Chinese institutional background. The results show that both state ownership and the 2005 split share reform attenuate the mitigating effect of corporate philanthropy on crash risk. Specifically, the negative relation between corporate philanthropy and crash risk is less pronounced for state-owned enterprises than for non-state-owned enterprises, and it is also less pronounced after firms accomplish the split share reform. Further, this effect is more pronounced for firms with greater financial risks and poorer performance. Our paper contributes to the growing literature on the determinants of stock price crash risk and the economic consequences of corporate philanthropy. It also offers useful guidance to firms that are seeking to reduce stock price crash risk in emerging markets. [ABSTRACT FROM AUTHOR]

Insiders are often legal users who are authorized to access system and data. If they misuse their privileges, it would bring great threat to system security. In practice, we could not have any knowledge about fraud pattern in advance, and most malicious behaviors are often in accordance with security rules; thus, it is difficult to predefine regulations for preventing all kinds of frauds. In this paper, we propose a data-driven evaluation model to detect malicious insiders, which audits user behaviors from both parallel and incremental aspects. Users are grouped together according to their positions and responsibilities, based on which the normal pattern is learned. For each user, a routine behavior pattern is also learned for historical assessment. Then, users are evaluated against both group patterns and routine patterns by probabilistic methods. The deviation degree is adopted as an evidence to justify an anomaly. We also recognize the abnormal activities that often make a user behavior much deviate, which can help an administrator revisit security policies or update activity weights in assessment. At last, experiments are performed on several real dataset. [ABSTRACT FROM AUTHOR]

Based on the screening of biocatalysts and reaction conditions including solvent, water content, temperature, enzyme loading, and reaction time, lipase from porcine pancreas (PPL) showed the prominent promiscuity for the Knoevenagel condensation between 1,3-dihydroindol-2-one heterocycle and aromatic aldehydes. Under the optimized procedure, both electron-withdrawing and electron-donating substituent of aldehydes substrates could react efficiently, and benzylidene-indolin-2-ones were obtained in excellent yields (75.0-96.6 %). Graphical abstract: Benzylidene-indolin-2-ones derivatives were efficiently synthesized by the Knoevenagel condensation between various aromatic aldehydes and 1,3-dihydroindol-2-one catalyzed by lipase from porcine pancreas with excellent yields obtained. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Social tags take an important role in exploratory search. In collaborative tagging systems, users are allowed to annotate resources with tags. The significant challenges in such systems are the uncertainty of tag quality and the incomplete annotation on a large number of resources. Based on the observation that these problems can be statistically negligible after receiving sufficient tags, we propose a novel incentive mechanism to reward taggers according to the quality of their bookmarks, called the Quality-based dynamic Incentive Mechanism ( QIM). To well evaluate the quality of bookmarks, we design some quantitative evaluation methods. The reward allocation function is proposed to allocate the budget to different taggers based on their bookmark quality and the tagging states of annotated resources. We perform experiments to evaluate our method on three public datasets collected from real tagging systems. Comparing with previous works, the adopted principle of ' high quality deserves high price' in this paper can encourage users to annotate seriously. The experimental results show that our method gets higher tagging quality of resources under a fixed budget. Moreover, it requires less time and less money to achieve the stable tagging state of a system. [ABSTRACT FROM AUTHOR]

Physiological signals can contain abundant personalized information and indicate health status and disease deterioration. However, in current medical practice, clinicians working in the general wards are usually lack of plentiful means and tools to continuously monitor the physiological signals of the inpatients. To address this problem, we here presented a medical-grade wireless monitoring system based on wearable and artificial intelligence technology. The system consists of a multi-sensor wearable device, database servers and user interfaces. It can monitor physiological signals such as electrocardiography and respiration and transmit data wirelessly. We highly integrated the system with the existing hospital information system and explored a set of processes of physiological signal acquisition, storage, analysis, and combination with electronic health records. Multi-scale information extracted from physiological signals and related to the deterioration or abnormality of patients could be shown on the user interfaces, while a variety of reports could be provided daily based on time-series signal processing technology and machine learning to make more information accessible to clinicians. Apart from an initial attempt to implement the system in a realistic clinical environment, we also conducted a preliminary validation of the core processes in the workflow. The heart rate veracity validation of 22 patient volunteers showed that the system had a great consistency with ECG Holter, and bias for heart rate was 0.04 (95% confidence interval: −7.34 to 7.42) beats per minute. The Bland-Altman analysis showed that 98.52% of the points were located between Mean ± 1.96SD. This system has been deployed in the general wards of the Hyperbaric Oxygen Department and Respiratory Medicine Department and has collected more than 1000 cases from the clinic. The whole system will continue to be updated based on clinical feedback. It has been demonstrated that this system can provide reliable physiological monitoring for patients in general wards and has the potential to generate more personalized pathophysiological information related to disease diagnosis and treatment from the continuously monitored physiological data. [ABSTRACT FROM AUTHOR]

Motile subpopulations in microbial communities are believed to be important for dispersal, quest for food, and material transport. Here, we show that motile cells in sessile colonies of peritrichously flagellated bacteria can self-organize into two adjacent, centimeter-scale motile rings surrounding the entire colony. The motile rings arise from spontaneous segregation of a homogeneous swimmer suspension that mimics a phase separation; the process is mediated by intercellular interactions and shear-induced depletion. As a result of this self-organization, cells drive fluid flows that circulate around the colony at a constant peak speed of ~30 µm s−1, providing a stable and high-speed avenue for directed material transport at the macroscopic scale. Our findings present a unique form of bacterial self-organization that influences population structure and material distribution in colonies. Motile and non-motile subpopulations often coexist in bacterial communities. Here, Xu et al. show that motile cells in colonies of common flagellated bacteria can self-organize into two adjacent motile rings, driving stable flows of fluid and materials around the colony. [ABSTRACT FROM AUTHOR]