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The management of small vessels has always been key to maritime administration. This paper presents a novel method for recognizing small fishing vessels based on laser sensors. Using four types of small fishing vessels as targets, a recognition method for small fishing vessels based on Markov transition field (MTF) time-series images and VGG-16 transfer learning is proposed. In contrast to conventional methods, this study uses polynomial fitting to obtain the contours of a fishing vessel and transforms one-dimensional vessel contours into two-dimensional time-series images using the MTF coding method. The VGG-16 model is used for the recognition process, and migration learning is applied to improve the results. The UCR time-series public dataset is used as a transfer learning dataset for the MTF time-series image encoding. The experiment demonstrates that the proposed method exhibits higher accuracy and performance than 1D-CNN and other general neural network models, and the highest accuracy rate is 98.92%. [ABSTRACT FROM AUTHOR]

Aiming at the problem of permeability enhancement in deep coal roadway strip, it proposed a pressure relief roadway permeability enhancement model, and the model was verified through experiments, theoretical calculations, and field tests. The experiment reveals that the unloading of gas-containing coal can achieve the effect of permeability enhancement. Theoretical calculation shows that with the increase of the distance from the coal seam, the overlying coal seam's permeability enhancement multiple and the width of the significant permeability enhancement zone gradually decrease, and the width of the general permeability enhancement zone gradually increases and then stabilizes. Field tests show that the pressure relief roadway is arranged 9 m directly below the coal seam; the overlying coal strata has a significant pressure relief and permeability enhancement effect. This research can provide reference value for the high-efficiency permeability enhancement in the deep coal roadway strip. [ABSTRACT FROM AUTHOR]

Rumors circulating on social media platforms have consistently represented a substantial threat to societal security and stability. Both academia and the industry have dedicated heightened focus to addressing the issue of rumor detection. Recent research has made significant progress in using deep neural networks to model the textual content and propagation structure of rumors. However, these methods model rumor-related features at a coarse-grained level and do not take full advantage of the various contextual information associated with rumors. In this paper, we propose a new model called Hybrid Rumor Detection Model with Co-Attention Mechanisms(CoAHRD), which utilizes the original tweet content, social context information, and user information for rumor detection. First, we use the Fine-Grained Feature Learning(FGFL) algorithm to extract fine-grained features from the tweets. Based on this, we use the Graph Convolutional Network(GCN) to learn the Multi-relation graph propagation structure features of rumors. Next, we combine FGFL features with temporal encoding information to model the temporal structure of rumors. Then, we introduce a User Feature-Based Co-Attention Network(UFCoAN) to learn the tendency of different users to spread rumors. Finally, we fuse the above features through a fully connected layer and perform rumor detection. Extensive experiments on two publicly available datasets, PHEME and TWITTER15, show that our method outperforms the current mainstream methods. In particular, in terms of accuracy, our model improves by 0.9% and 1.6% over the best baseline method on the Twitter15 and PHEME datasets, respectively. • BERTWeet and saliency learning for fine-grained modelling of rumour text. • Using attention mechanisms to learn the temporal structure of rumours. • As a complementary task to rumour detection, segmentation of users into different groups using a user attention network. [ABSTRACT FROM AUTHOR]

Insulation performance testing of gas-insulated switchgear (GIS) and treatment of SF 6 decomposition products under partial discharge are two crucial studies. In this paper, the adsorption behavior and sensor properties of five characteristic decomposition gases of SF 6 (HF, H 2 S, SO 2 , SOF 2 , SO 2 F 2) on intrinsic and CoO-doped SnSe monolayers are investigated in detail based on density-functional theory. The results showed that the adsorption behaviors of HF, H 2 S, SOF 2 and SO 2 F 2 on SnSe monolayers were all physisorption among which the best adsorption was SO 2 with an adsorption energy of −0.618 eV, which is a weak chemisorption. After doping with CoO, the adsorption capacity of SnSe monolayer for five gases was significantly enhanced, in which the adsorption energies for SO 2 and SOF 2 reached −1.356 eV and −1.175 eV, respectively. In addition, the conductivity of the system is greatly improved, with the bandgap changing from 1.129 eV to 0 eV. The microscopic mechanism of the interaction of gas molecules with CoO-SnSe monolayers has been revealed by energy band structure (E g), density of states (DOS), Milligan charge analysis (∆ Q) and electrostatic potential. Finally, the sensitivity (S) and desorption time (τ) of the five adsorption systems were calculated to illustrate the macroscopic gas-sensitive properties of the system. This work will help to explore the application of CoO-SnSe monolayers in SF 6 decomposition gas sensing detection and adsorption treatment. [Display omitted] • Doping greatly improves the conductivity of the system, and the adsorption effect of doped system on SO 2 and SOF 2 is significantly improved. • The change of electronic characteristics of doped system is expounded. • The sensing characteristics of adsorption system are calculated, and the possibility of SOF 2 as the target gas for CoO-SnSe sensing device to evaluate GIS insulation performance is explored. [ABSTRACT FROM AUTHOR]

To solve the high-stress hazard faced in the process of deep mining process, the pressure relief characteristics of gas bearing coal and the deformation characteristics of surrounding rock in deep roadway are studied by means of laboratory test, similar simulation analysis, and field investigation. The investigation results and engineering application showed that the specimens could more easily reach the failure point due to the axial pressure relief under high confining pressure. In addition, the deformation and failure degree of the surrounding rock was higher due to the disturbance from the deep high-stress roadway. The scope of the height affected by the pressure relief of the overlying strata reached above 10 m. Moreover, the initial gas emission could reach 4.41–14.39 times that of the original coal seam by drilling a hole in the coal seam at 10 m from the roof. Thus, the short-distance floor roadway exerted an obvious pressure relief effect on the overlying coal seam. [ABSTRACT FROM AUTHOR]

Grazing exclusion (GE) is commonly used worldwide in the management of degraded grasslands. While the effects of GE on soil organic carbon (SOC) and soil total nitrogen (STN) are intensively studied, little consensus has emerged due to highly variable background conditions. Drawing on 4081 observations from over 200 experiments worldwide, we applied a hierarchical meta-analysis to evaluate the effect of GE on SOC and STN. Overall, GE significantly increased SOC (14.74%) and STN (28.75%) compared to traditional grazing. However, the effect was mainly dependent on GE duration, site elevation and the mean annual precipitation. The improvement in SOC and STN were greatest when the duration of GE exceeded 10 years and the mean annual temperature, precipitation and elevation ranged between 0°C and 10 °C, less than or equal to 300 mm, and 1500 m–2500 m, respectively. In temperate and desert grasslands, long-term GE (>10 years) improved SOC and STN, whereas in meadow grasslands, short-term GE (≤5 years) contributed the most to their improvement. Long-term GE (>10 years) had a significant positive effect on SOC and STN in historically lightly and heavily grazed areas, but not in historically moderately grazed areas. As the response of SOC and STN under GE duration can vary from positive to negative based on different conditions, an appropriate GE duration implementation strategy should be developed in a context-dependent manner during future restoration of degraded grasslands. [ABSTRACT FROM AUTHOR]

Micro- and nanometallic structures that exhibit extraordinary optical transmission (EOT) have attracted much attention for their potential applications in photonic devices. However, most existing reports have only discussed EOT at one specific wavelength, which limits its use in multi-wavelength applications. Here, we experimentally demonstrate EOT at multiple wavelengths through an asymmetric corrugated thin silver film due to simultaneous excitation of multiple plasmonic resonances at both interfaces. A unique method that applies single-pulse nanosecond laser interference lithography is introduced to produce the silver grating, which shows high quality over large area. At oblique incidence, each EOT peak is observed to split into two peaks oppositely shifted towards higher and lower frequencies. At some specific angles of incidence, overlap of these shifted peaks gives rise to distorted transmission spectra. Our method may find applications involving multiple wavelengths such as multi-wavelength bandpass filters, anti-Stokes Raman scattering spectroscopy, enhanced four-wave mixing, and so on. [ABSTRACT FROM AUTHOR]

Graphene has been demonstrated to have extraordinary large second order nonlinear susceptibility that can be applied in generating mid-infrared (MIR) and terahertz waves through the difference frequency process. In this study, we exploit the highly localized electric fields caused by plasmon resonances to increase the nonlinear response from graphene. The proposed structure contains a graphene sheet on a gold grating substrate that sustains both surface plasmons at the near-infrared on the gold surface and plasmons at the MIR on the graphene surface. Based on finite difference time domain (FDTD) numerical simulations, more than 3 orders of magnitude improvement of the MIR generation efficiency is obtained by placing graphene sheets on a gold grating substrate under resonance conditions instead of placing them on a flat substrate. With the same gold grating substrate, MIR waves tunable from 30 to 55 THz are generated by tuning the gate voltage of the graphene sheet. [ABSTRACT FROM AUTHOR]

Compact surface plasmon resonance (SPR) sensors are highly demanded due to their small size, low cost, and wide application scenarios compared with benchtop sensors. To realize high-precision spectral or angular analysis, most compact SPR sensors need spectrometers or rotation stages, which increase the cost of the device. We demonstrate a low-cost and compact SPR sensor by utilizing a single grating as a coupler and a disperser. The polychromatic light emitted from a light-emitting diode was coupled to surface plasmon modes by a grating made from a digital versatile disc-recordable disc. The light was dispersed by the same grating and collected by a linear charge-coupled device. The real-time detection of the SPR spectra and the resonant wavelengths was realized by homemade software based on the laboratory virtual instrument engineering workbench. By measuring different concentrations of glucose solution and sodium chloride solution, we obtain a high refractive index (RI) resolution of 5.52 × 10 − 5 RI unit. This compact SPR sensor can be applied in the areas of food safety, environmental monitoring, medical diagnosis, and so on. [ABSTRACT FROM AUTHOR]

The wavelength dependence of laser induced surface damage in fused silica is experimentally studied in a wide wavelength range from 260 to 1550 nm. An optical parametric oscillator system is used to provide the tunable laser pulses with a duration of 5 ns. In the experiments, the exit surface of the silica slice is observed to be damaged prior to the entrance surface. The damage threshold decreases gradually as the wavelength decreases from 1550 to 324 nm and drops suddenly at 324 nm, which corresponds to a half of 7.66 eV. This wavelength dependence can be explained by a defect assisted multiphoton absorption mechanism. By fitting the experimental data with a power law equation, the damage threshold is found to be proportional to the 3.47-th power of wavelength in the range of 325–685 nm and 1.1-th power of wavelength in the range of 260–1550 nm. [ABSTRACT FROM AUTHOR]

The article presents the discussion on structural basis for the binding and selectivity of peptides to CTRs and AMYRs being important for future drug discovery and development. Topics include Amylin receptors (AMYRs) being the heterodimers of the calcitonin (CT) receptor (CTR) developing as obesity treatments; and DACRAs being based on amylin-template peptides versus calcitonin-template peptides activating the target receptors by similar or distinct molecular mechanisms.

The South-to-North Water Transfer Jiangsu Water Supply Area (JWSA) is a mega inter-basin water transfer area (water source) that provides water resources from JiangHuai, combines drainage and flooding management, and regulates nearby rivers and lakes. Analyzing the spatiotemporal soil moisture dynamics in the area will be informative regarding agricultural drought along with flood disaster assessment and will provide early warning studies. Therefore, we evaluated the quality of European Space Agency Climate Change Initiative Soil Moisture (ESA CCI_SM) data in the South-North Water Transfer JWSA. Furthermore, we utilized ensemble empirical modal decomposition, Mann-Kendall tests, and regression analysis to study the spatiotemporal variation in soil moisture for the past 29 years. The CCI _SM data displayed a high correlation with local soil measurements at nine sites. We next analyzed the CCI_SM data from three pumping stations (the Gaogang, Hongze, and Liushan stations) in the South-North Water Transfer JWSA. These stations had similar periodic characteristics of soil moisture, with significant periodic fluctuations around 3.1 d. The overall soil moisture at the three typical pumping stations demonstrated an increasing trend. We further investigated whether abrupt soil moisture changes existed at each station or not. The spatial distribution of soil moisture in the South-North Water Transfer JWSA was characterized as "dry north and wet south", with higher soil moisture in winter, followed by autumn, and low soil moisture in spring and summer. Although the linear trend of soil moisture in the South-North Water Transfer JWSA varied in significance, the overall soil moisture in the JWSA has increased over the past 29 years. The areas with significantly enhanced soil moisture are mostly distributed in the Yangzhou and Huai'an areas in the southeastern part of the study area. The areas with significantly decreased soil moisture are small in size and mostly located in northern Xuzhou. [ABSTRACT FROM AUTHOR]

Climate change and overgrazing are believed by policy makers to have been the drivers of grassland degradation in China over the past thirty years. However, recent work has suggested that policies that have led to privatization of use rights and household enclosures are more important drivers of degradation. An analysis of available evidence from scienti fic publications and national survey data relating to climate change, livestock numbers, and management policy was undertaken to evaluate the case for each of these possible drivers of degradation. The analysis suggests that, to date, policy measures imposed to avoid the 'tragedy of the commons' have been more important than either climate change or overgrazing as a driver of degradation. The resulting fragmentation of the pastoral landscape has caused localized grazing pressure and spatial and temporal mismatches between grassland production and livestock access to forage. Grazing rights negotiated and allocated at a multiple-household level would allow greater productivity, better rangeland condition, possible advantages of scale and pooling of herder resources, and better potential to adapt to future climate change. [ABSTRACT FROM AUTHOR]

Abstract: Rangeland degradation on the Qinghai–Tibetan Plateau is a growing concern, often attributed to climate change and overgrazing. A minority of researchers have suggested instead that degradation may be caused by changes in land management, particularly enclosures and the contracting of long-term rangeland use rights to households. However, these claims have been hampered by a lack of empirical evidence. This field experiment is the first to compare rangeland conditions over time in the case of different management regimes on the Qinghai–Tibetan Plateau, specifically single-household versus multi-household management. A survey of vegetation properties in Maqu County, Gansu province in 2009, and repeated in 2011, examined the differences between single- and multi-household management in terms of vegetation biomass, cover, and species richness. In 2009, the biomass of the sedge group under multi-household management was significantly higher than that under single-household management. In 2011, biomass, vegetation cover, and species richness were all significantly higher under multi-household management than single-household management. These data suggest the flaws of the tragedy of the commons assumptions underlying single-household management. [Copyright &y& Elsevier]

Abstract: Thrombosis and restenosis are the main causes of failure of cardiovascular and other blood-contacting biomedical devices. It is recognized that rapid endothelialization is a promising method for preventing these complications. Convincing evidence in vivo has further emerged that the vascular homing of endothelial progenitor cells (EPCs) contributes to rapid endothelial regeneration. This study deals with improving the hemocompatibility and enhancing EPC colonization of titanium by covalently bonding PEG600 or PEG4000, then end-grafting of an anti-CD34 antibody. For this, a chemically hydroxylated titanium surface was aminosilanized, which was further used for covalent grafting of polyethylene glycol and the antibody. The grafting efficiency was verified in each step. In vitro platelet adhesion analysis confirmed superior hemocompatibility of the modified surface over the control. Affinity of EPC to the surface and inhibition of smooth muscle cell adhesion, two prerequisites for endothelialization, are demonstrated in in vitro cell culture. While the coating selectively stimulates EPC adhesion, its antifouling properties prevent formation of an extracellular matrix and proliferation of the cells. Additional affinity for matrix proteins in the coating is considered for further studies. Potent inhibitory effect on macrophage activation and the relative stability of the coating render this technique applicable. [Copyright &y& Elsevier]

• The R:S ratio and root morphology were affected by duration of grazing exclosure. • Both were mainly influenced by soil nitrate nitrogen. • The root diameter showed little change with an increase of duration. • The root density and root length density increased with an increase of duration. • The relationship between root biomass and root morphology changed with duration. Unsustainable human actions and climate change have threatened global grasslands and lead to biodiversity loss and compromised ecosystem functions. Widely considered to be an effective approach to restore degraded grasslands, grazing exclosure (GE) likely affects biomass allocation and root morphology in the long-term, although their impacts are yet to be documented. The objective of this study was to investigate the effects of grazing exclosure durations of 5, 22, and 39 years (GE 5 , GE 22 , GE 39 , respectively) on root:shoot biomass allocation (R:S ratio) and root morphology — including root average diameter (RAD), root density (RD), specific root length (SRL), specific root area (SRA), and root length density (RLD) — in an alpine grassland on the Qinghai-Tibetan Plateau. Seasonal grazing (SG) land served as a control. In the 0−0.30 m soil layer, the R:S ratios of the SG (1.27) and GE 5 sites (0.90) were significantly lower than that of the GE 39 site (2.14). However, there was no difference between the GE 22 (1.83) and GE 39 sites. The R:S ratio of the 0−0.15 m soil layer showed an increasing trend with duration of grazing exclosure and had a significantly greater value under GE 39 (1.89) than under GE 5 (0.76). However, the R:S ratios for the 0.15−0.30 m soil layer (0.14, 0.28 and 0.25 for GE 5 , GE 22 , and GE 39 , respectively) showed no significant changes with grazing exclosure duration. In the 0−0.30 m soil layer across sampled sites, RAD remained constant, RD and RLD exhibited an increasing trend, while SRA and SRL displayed a slightly decreasing trend with grazing exclosure duration. Below-ground biomass (BGB) was most strongly related to RLD across all sites; to RD and RLD at the GE 5 and GE 22 sites, and to RAD and RLD at the GE 39 site. Both R:S ratio and root morphology were mainly influenced by soil nitrate nitrogen. Although long-term grazing exclosure enhanced BGB and R:S ratio, soil nutrients declined with increasing exclosure duration. Therefore, to achieve improved ecosystem functions, grazing exclosure should be used with caution in this area or other similar regions around the world. [ABSTRACT FROM AUTHOR]

Gas outbursts pose a significant threat in the mining of deep low‐permeability coal seams. As mining depth increases, there is a rise in coal and gas dynamic disasters, rendering the gas outburst prevention technology from shallow mining areas unsuitable for deep coal seam exploitation. Addressing the challenges posed by deep, highly gassy coal seams, this study introduces a gas outburst prevention technology integrating destressing in the close distance underlying roadway with gas drainage. The article investigates the relevant technical parameters and assesses the feasibility of this approach. First, it establishes destressing model for the underlying roadway to derive an analytical solution for stress distribution in the coal seam. Second, appropriate technical parameters are designed considering the seepage characteristics of gas in the coal seam. Finally, the gas drainage technical scheme is implemented at Qujiang coal mine to verify its on‐site effectiveness. Field test results indicate an increase in gas permeability within the coal seam following destressing in the underlying roadway, accompanied by significant improvements in the efficiency of gas drainage and the advancement speed of the coal roadway. Specifically, the driving speed of the coal roadway has escalated from 40 m/month to 150 m/month. These outcomes demonstrate the potential of this technology as a promising approach for preventing gas outbursts in the challenging context of deep, low‐permeability coal seams, facilitating swift coal roadway excavation. [ABSTRACT FROM AUTHOR]

Surface plasmon resonance (SPR) sensors based on metal gratings have received much attention for designing compact and portable biosensors. In this paper, we systematically optimize SPR sensors based on sinusoidal and rectangular gratings to improve the performance of this kind of sensors. A parameter (FOM*) is defined to evaluate the sensor performance, which combines the sensitivity, FWHM , and depth of the SPR absorption peak. We find that grating period of 560 nm is suitable to locate the SPR peaks in the optimal response range of silicon detectors and ensures high sensitivity. For sinusoidal gratings, the highest FOM* of 99.25 is achieved at grating depth of 15 nm. The highest FOM* for rectangular grating with continuous metal film is 123.70 when grating depth and duty cycle are 12 nm and 0.3, respectively. With grating depth of 24 nm and duty cycle of 0.8, the highest FOM* of 25.23 is obtained for rectangular grating with discontinuous metal film. These optimization results can be directly used to improve the detection limit of compact SPR sensors. • SPR sensors based on sinusoidal and rectangular gratings are optimized. • FOM* is defined to evaluate the sensor performance. • The highest FOM* of 123.7 is achieved for rectangular grating with continuous metal film. • Continuous gratings show better performance than the discontinuous gratings. [ABSTRACT FROM AUTHOR]

• Elevation and slope aspect affected leaf stoichiometry of Oxytropis ochrocephala. • Variation of leaf stoichiometry with elevation was mainly affected by MAT, SOC and SOC:STP. • Variation of leaf stoichiometry with slope aspect was mainly affected by ST and SWC. Slope aspect and elevation gradient, important topographic factors, affect plant growth and leaf carbon:nitrogen:phosphorus (C:N:P) stoichiometry by regulating local water and energy balances. The response of leaf stoichiometry to topographic factors reflects plant adaptation strategies to different habitats. Common in various grasslands across China, Oxytropis ochrocephala Bunge. is well known in pastoral areas for its toxicity. The effects of partial or full slope sunniness (south-facing) or shadiness (north-facing) and elevation (2400 m, 2600 m, 2800 m, 3000 m, or 3200 m) on the leaf C:N:P stoichiometry of O. ochrocephala was investigated in northwest China's Qilian Mountains. While leaf C:N:P stoichiometry of O. ochrocephala changed with elevation, there was no uniform pattern of change: the greatest leaf C and P concentrations ([C] leaf , and [P] leaf) were measured at an elevation of 2800 m (417.81 g kg−1 and 1.17 g kg−1, respectively); the lowest [C] leaf was 360.43 g kg−1 at 2400 m, and the lowest [P] leaf was 0.81 g kg−1 at 2600 m. The greatest leaf N concentration ([N] leaf) was 38.29 g kg−1 at 3200 m, and the lowest was 31.94 g kg−1 at 2600 m. Leaf C:N, C:P and N:P ratios were all relatively greater at 2600 m. Across the elevation gradient, O. ochrocephala leaf nutrient concentrations and their stoichiometries were mainly determined by mean annual temperature, soil organic carbon, and soil organic carbon to soil total phosphorus ratio. The [C] leaf , [N] leaf , and [P] leaf were significantly greater on north-facing slope aspects (393.86 g kg−1, 38.04 g kg−1, and 1.16 g kg−1, respectively) than on south-facing slope aspects (365.39 g kg−1, 32.98 g kg−1, and 0.92 g kg−1, respectively). Leaf C:N, C:P, and N:P ratios were significantly lower on north-facing slope aspects (10.43, 416.49, and 39.73, respectively) than on south-facing slope aspects (11.14, 512.57, and 45.98, respectively). Differences in leaf nutrient concentrations and their stoichiometries in O. ochrocephala leaves between slope aspects were mainly determined by soil temperature and soil moisture content. In terms of leaf N:P ratios across the elevation gradient and the two slope aspects, results indicated that the growth of O. ochrocephala in the study region was mainly restricted by P. [ABSTRACT FROM AUTHOR]

A pressure relief and permeability enhancement method through short-distance floor roadway was proposed to solve the difficult outburst prevention during the gas extraction at the coal roadway strips in deep outburst coal seams with high ground stress and low gas permeability. On the basis of an equivalent model of the surrounding rock in a deep roadway, the analytical solutions of deep roadway excavation to the stress and deformation of pressure relief at overlying short-distance coal roadway strips were obtained using the unified strength theory and nonassociated flow rules. Next, the criteria for determining the reasonable position of floor roadway were established, and a mechanical model of short-distance floor roadway for the pressure relief and permeability enhancement zone at the overlying coal seam was constructed. Finally, the scope of the zonal disintegration at the coal roadway strips in the elastic and elastic–plastic zones of the surrounding rock in the roadway, as well as the expression of gas permeability change, was given. The engineering trial calculation and practice showed that the stress and strain of the surrounding rock in the roadway were evidently influenced by the intermediate principal stress coefficient. Moreover, the vertical stress and vertical displacement of overlying coal seam were gradually reduced with the increase in the intermediate principal stress coefficient and vertical distance of the floor roadway. The minimum reasonable distance arranged for the 213 floor roadway in Qujiang Coal Mine was 6.21 m, and the effective pressure relief should be conducted within 10.6 m from the coal seam floor. When the pressure relief was located at 9.0 m from the coal seam floor, the investigation results were basically consistent with the theoretical analysis results, exerting obvious pressure relief and permeability enhancement effects on the overlying short-distance coal roadway strips. [ABSTRACT FROM AUTHOR]

Gullies of different scales and types have developed in the Loess Plateau, China. Differences in the amount of gully erosion influence the development, evolution, morphology, and spatial distribution of these gullies. The strengths of headward erosion on the gully shoulder line are used to dictate soil and water conservation measures. In this study, six typical loess landforms in the Loess Plateau were selected as sampling sites: Shenmu, Suide, Ganquan, Yanchuan, Yijun, and Chunhua, which respectively represent loess–aeolian and dune transition zones, loess hills, loess ridge hills, loess ridges, loess long-ridge fragmented tablelands, and loess tablelands. Using 5 m resolution digital elevation model data from the National Basic Geographic Information Database, a small representative watershed was selected from each sampling site to obtain elevation data on the terrain profiles of gully shoulder lines. Multifractal detrended fluctuation analysis (MF-DFA) was used to conduct statistical and comparative analysis of the elevation fluctuation characteristics of these profiles. The results show that MF-DFA is capable of detecting active gully erosion sites. Sites of active gully erosion are concentrated in Shenmu and Suide but more widely distributed in the other five sites. The results provide a scientific basis for small watershed management planning and the design of soil and water conservation measures. [ABSTRACT FROM AUTHOR]

In this paper, we derive the analytical expression for the sensitivity of grating-based surface plasmon resonance (SPR) sensors working in wavelength interrogation. The theoretical analysis shows that the sensitivity increases with increasing wavelength and is saturated beyond a certain wavelength for Au and Ag gratings, while it is almost constant for Al gratings in the wavelength range of 500 to 1000 nm. More importantly, the grating period (P) and the diffraction order (m) dominate the value of sensitivity. Higher sensitivity is possible for SPR sensors with a larger grating period and lower diffraction order. At long wavelengths, a simple expression of P/|m| can be used to estimate the sensor sensitivity. Moreover, we perform experimental measurements of the sensitivity of an SPR sensor based on an Al grating to confirm the theoretical calculations. [ABSTRACT FROM AUTHOR]

Livestock grazing is the primary practice in alpine meadows and can alter soil microbiomes, which is critical for ecosystem functions and services. Seasonal grazing (SG) and continuous grazing (CG) are two kinds of different grazing practices that dominate alpine meadows on the Qinghai-Tibetan Plateau (QTP), and how they affect soil microbial communities remains in-depth exploration. The present study was conducted to investigate the effects of different grazing practices (i.e. , SG and CG) on the diversity, composition, and co-occurrence networks of soil bacteria and fungi in QTP alpine meadows. Soil microbial α- and β-diversity showed no obvious difference between SG and CG grasslands. Grazing practices had little impact on soil microbial composition, except that the relative abundance of Proteobacteria and Ascomycota showed significant difference between SG and CG grasslands. Soil microbial networks were more complex and less stable in SG grasslands than that in CG grasslands, and the bacterial networks were more complex than fungal networks. Soil fungal diversity was more strongly correlated with environmental factors than bacteria, whereas both fungal and bacterial structures were mainly influenced by soil pH, total nitrogen, and ammonium nitrogen. These findings indicate that microbial associations are more sensitive to grazing practices than microbial diversity and composition, and that SG may be a better grazing practice for ecological benefits in alpine meadows. • Soil microbial networks more complex in SG than CG grasslands. • No difference in soil microbial α- and β-diversity between SG and CG grasslands. • Grazing practices have little effect on soil microbial composition. • Soil fungi more correlated with environmental factors than bacteria. • SG may be more conducive to sustainable alpine meadow ecosystem development. [ABSTRACT FROM AUTHOR]

In addition to changes in land use and cover, changes in land management pattern can also have a significant effect on soil fertility. However, to date, changes in grassland grazing management pattern caused by policies have received less attention in terms of their impact on soil fertility. In this paper, we investigated the influence of two different grazing management patterns: the multi-household grazing management pattern (consisting of pastures managed by two or more households with no fences separating them) and the single-household grazing pattern (with fences between adjacent pastures managed by different households), which were implemented after the enactment of grassland contract policy, on soil fertility in the Qinghai-Tibetan Plateau. Our hypothesis was that soil fertility differed between the two grazing management patterns. We selected five study sites with both grazing management patterns in Maqu County on the eastern Qinghai-Tibetan Plateau and sampled 30 winter grasslands from each grazing management pattern to explore differences in soil organic carbon, soil total nitrogen, and soil total phosphorus. We showed that these indicators of fertility status were significantly greater under the multi-household grazing management pattern (47 g C kg−1, 4.6 g N kg−1, and 0.77 g P kg−1) compared to the single-household grazing management pattern (43 g C kg−1, 4.3 g N kg−1, and 0.73 g P kg−1). This is the first study of the effects of grazing management pattern on soil fertility in this environment, and it indicated that the multi-household grazing management pattern could maintain better soil fertility and help to support sustainable use of these grasslands. [ABSTRACT FROM AUTHOR]

Collaborative filtering recommendation with implicit feedbacks (i.e., clicks, views, check-ins) has been gaining increasing attention in various real applications. Tagging information is the common resource to complement implicit feedbacks to assist collaborative filtering recommendation. However, existing tag-aware recommendation methods still suffer from the problem of high dimension and sparsity of tagging information. They also fail to realize that recommendation is inherent a ranking-oriented optimization task. To this end, we propose a novel tag-aware recommendation framework by incorporating tag mapping scheme into ranking-based collaborative filtering model, to boost ranking-oriented personalized recommendation performance. We first build ranking-oriented optimization model based on Bayesian personalized ranking optimization criterion with matrix factorization, by leveraging implicit feedbacks to learn the latent feature vectors of users and items. Then, we propose an explicit-to-implicit feature mapping scheme, mapping the high-dimensional and sparse explicit tags (i.e., user-tag weighting matrix and item-tag weighting matrix) to low-dimensional and compact implicit features of uses and items. This could serve as the regularization constraint of latent features derived from implicit feedbacks. To further enhance recommendation performance, we also introduce users' neighbor relationships to regularize user latent features based on manifold learning. Experiments on real-world recommendation datasets show that the proposed recommendation method outperformed competing methods on ranking-oriented recommendation performance. [ABSTRACT FROM AUTHOR]

A simple optical lens plays an important role for exploring the microscopic world in science and technology by refracting light with tailored spatially varying refractive indices. Recent advancements in nanotechnology enable novel lenses, such as, superlens and hyperlens, with sub-wavelength resolution capabilities by specially designed materials' refractive indices with meta-materials and transformation optics. However, these artificially nano- or micro-engineered lenses usually suffer high losses from metals and are highly demanding in fabrication. Here, we experimentally demonstrate, for the first time, a nonlinear dielectric magnifying lens using negative refraction by degenerate four-wave mixing in a plano-concave glass slide, obtaining magnified images. Moreover, we transform a nonlinear flat lens into a magnifying lens by introducing transformation optics into the nonlinear regime, achieving an all-optical controllable lensing effect through nonlinear wave mixing, which may have many potential applications in microscopy and imaging science. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanogratings were precisely fabricated via wet etching-assisted laser patterning. • Nanogratings' depth and period were controlled via etching time and exposure angle. • A single chip was applied for dual-mode biosensor combines SPR and SERS. • H-IgG was successfully detected with LODs of 23.5 nM (SPR) and 1.176 nM (SERS). This study introduces a dual-mode biosensor, combining surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS), to sensitively detect Human Immunoglobulin (H-IgG) on Au nanogratings. The Au nanogratings were fabricated on a single-crystal silicon surface using wet etching-assisted nanosecond direct laser interference patterning (DLIP), allowing precise control over period and depth. By optimizing the DLIP intersection angle and etching time, the resulting Au nanogratings exhibit remarkable SPR absorption dips in reflection spectra and robust localized SPR, rendering them highly responsive to local refractive index changes and conducive to strong localized electric fields for enhanced SERS activity. Notably, the 765 nm-period grating demonstrates a sensitivity at 751 nm/RIU and a resolution of 2.93 × 10−5 RIU. In SPR mode, protein A immobilization on the Au nanograting surface enables specific H-IgG binding, achieving a limit of detection (LOD) of 23.5 nM. In SERS mode, the biosensor exhibits better sensitivity, with a LOD of 1.176 nM. The SPR mode exhibits high linearity, while the SERS method enables sample identification based on characteristic peaks, enhancing specificity and accuracy. The synergy between these complementary modes offers multiple detection options and enhances result cross-validation, thereby improving assay accuracy and reliability. [ABSTRACT FROM AUTHOR]

To understand the intricacies of nutrient cycling and advance grassland restoration strategies, this study delves into the varying responses of leaf, litter, and root ecological stoichiometries to different durations of grazing exclosure (GE) on the ecologically vital Qinghai-Tibetan Plateau in eastern China. The investigation encompassed GE durations of 0 (seasonal grazing), 13, 22, and 39 years, revealing pivotal alterations in ecological stoichiometries. Notably, GE markedly augmented leaf and root carbon (C) levels and the carbon to nitrogen (C:N) ratio, while diminishing leaf and root nitrogen (N), and root N to phosphorus (N:P) ratios. Intriguingly, with prolonged GE, root C and C:N exhibited a minor decline, and root N slightly increased, albeit remaining significantly lower than in seasonally grazed areas. Leaf N, along with litter P, C:P, and N:P ratios, displayed remarkable stability over time. This suggests that ecological stoichiometries of different plant components responded differently to GE duration. Across plant components, soil NH 4 + N emerged as a predominant factor influencing their stoichiometries, underscoring the complex interplay between vegetation and soil. There was the interconnectedness of C, N, and P among leaf, litter, and roots, highlighting understanding of these elements' cycles. This research, the first of its kind to assess the impact of extensive GE durations on leaf, litter, and root ecological stoichiometries on the Qinghai-Tibetan Plateau, offers insights for understanding ecological stoichiometries at the ecosystem level or between the above-ground part and below-ground part and for alpine grassland management. • Response of leaf, litter, and root stoichiometries to GE durations was examined. • Leaf and root stoichiometries were relatively sensitive to GE durations. • Leaf and root C and C:N increased but N and P decreased as GE duration extended. • Litter P, C:P, and N:P varied little across GE durations. • Leaf, litter, and root ecological stoichiometries were mainly regulated by NH 4 + N. [ABSTRACT FROM AUTHOR]

Vegetation classification models play an important role in studying the response of the terrestrial ecosystem to global climate change. In this paper, we study changes in global Potential Natural Vegetation (PNV) distributions using the Comprehensive Sequential Classification System (CSCS) approach, a technique that combines geographic information systems. Results indicate that on a global scale there are good agreements among maps produced by the CSCS method and the globally well-accepted Holdridge Life Zone (HLZ) and BIOME4 PNV models. The potential vegetation simulated by the CSCS approach has 6 major latitudinal zones in the northern hemisphere and 2 in the southern hemisphere. In mountainous areas it has obvious altitudinal distribution characteristics due to topographic effects. The distribution extent for different PNV classes at various periods has different characteristics. It had a decreasing trend for the tundra and alpine steppe, desert, sub-tropical forest and tropical forest categories, and an increasing trend for the temperate forest and grassland vegetation categories. The simulation of global CSCS-based PNV classes helps to understand climate-vegetation relationships and reveals the dynamics of potential vegetation distributions induced by global changes. Compared with existing statistical and equilibrium models, the CSCS approach provides similar mapping results for global PNV and has the advantage of improved simulation of grassland classes. [ABSTRACT FROM AUTHOR]

We introduce a new two-step method to fabricate silver-silicon gratings that can excite surface plasmons efficiently. The grating structure was firstly created on a flat silicon substrate by single-pulse nanosecond laser interference lithography. Next, a silver layer of 50 nm was evaporated on the silicon substrate. With proper laser energy, a silver-silicon grating with a period of 1120 nm and depth of 18 nm was successfully fabricated. This grating can produce high-quality surface plasmon resonance (SPR) peaks at various incident angles. Moreover, a SPR sensor was experimentally demonstrated based on the silver-silicon grating, which had high sensitivity of 961.5 nm/RIU and figure of merit of 60. Our method is an efficient way to fabricate periodically nanostructured metals at high speed and low cost. [ABSTRACT FROM AUTHOR]

Guanxinning injection (GXNI) is widely used in the treatments of cerebral thrombosis, cerebral hemorrhage, sequela, coronary disease, stenocardia, arrhythmia, and so on. For the herbal injections, more components should be characterized and quantified as much as possible to guarantee the drug safety. However, large numbers of the chemical constituents in the GXNI still remain unknown. In this study, ultrahigh performance liquid chromatography‐Q Exactive hybrid quadrupole‐orbitrap high‐resolution accurate mass spectrometry (UHPLC‐Q Orbitrap HRMS), in combination of nuclear magnetic resonance (NMR), was used to identify the components in GXNI, which led to the identification of 194 compounds. With the aid of solvent partition, more phthalides, diterpenoid quinines, and salvianolic acids were tentatively identified, and minor compounds with the other structural types were also detected. The structural diversity of phthalides and diterpenoid quinones were revealed by the structural network, and six phthalides and 13 diterpenoid quinones were further detected in GXNI with the help of the characteristic fragmentation pattern and structural network. In addition, NMR also revealed the presence of a series of primary metabolites in the GXNI, which could be used as a complimentary approach for the rapid identification of the chemical components in the traditional Chinese medicines (TCM). However, the unknown NMR signals of GXNI needed to be further identified to guarantee the drug safety. [ABSTRACT FROM AUTHOR]

With the increase of mining depth, the occurrence mechanism of coal and gas outburst becomes more complex, and stress‐dominated outburst disaster has become one of the major safety problems in deep coal mines. Therefore, stress relief of coal seam has become an urgent technical demand for outburst prevention method in deep mines. In this study, based on zonal disintegration characteristics of deep surrounding rock, a regional strip outburst prevention method, called strip stress relief combined with gas extraction through stress‐relief floor roadway, was proposed, and relevant in‐site investigations were carried out in the Qujiang coal mine in China. Our results show that the zonal disintegration phenomenon occurs in the high‐stress surrounding rock at great depths, and induces the stress‐relief effect on the upper coal seam, in which the permeability and extraction radius of boreholes are increased greatly. The results of deformation and failure of surrounding rock of floor roadway show that from the surface to deep regions, fractured and nonfractured zones were alternatively distributed in the surrounding rock of deep floor roadways, the damage degree of surrounding rock was gradually weakened, and the width of fractured area was gradually reduced. The displacement of surrounding rock also presented the characteristics of alternative distribution of wave peak and trough. Moreover, the deformation and failure of surrounding rock presented a time‐dependent rheological behavior. In the stress‐relief zone, the coal seam permeability was enhanced significantly, with the maximum value being 43 times larger than that of the original coal seam. The effective gas extraction radius of the borehole was improved by 15%‐45%. During the driving period of coal roadways, the outburst risk prediction indexes K1 and S of the working face were lower than the critical value, and the driving speed of the coal roadway improved from 40 m per month to 100 m per month. This indicates that the proposed strip regional outburst prevention method can simultaneously reduce the ground stress and the gas content, and can effectively eliminate the outburst risk of coal roadway in deep mines. [ABSTRACT FROM AUTHOR]

A sandwich-type fluorescent biosensor for the determination of tumor-related exosome was designed. It is based on magnetic nanoparticle (MNP) capture and horseradish peroxidase (HRP) catalysis. MNPs were used as the substrate to capture exosomes by modifying the CD63 antibody on MNPs surface. After that, the biotinylated epithelial cell adhesion molecule (EpCAM) antibody was used to capture the tumor-related exosomes, which specifically express EpCAM. A novel method for the fluorescence measurement of tumor-associated exosome was achieved, with a detection limit as low as 200 (± 9) particles mL−1. The analytical range of this method is from 576 (± 15) particles mL−1 to 5.76 × 107 (± 5.1 × 105) particles mL−1. For the fluorescence measurement, the excitation wavelength was set to 320 nm. Fluorescent spectra were collected at emission wavelength in the range 370 to 550 nm; the data shown in the calibration plot were studied by using the fluorescence intensity at 406 nm. This sensor was also able to successfully detect the exosomes from the plasma of patients with hepatocellular carcinoma (HCC) and healthy humans. [ABSTRACT FROM AUTHOR]

To study the characteristics of the deformation and failure of coal during a coal and gas outburst, we developed an experimental apparatus that subjected coal samples to sudden unloading under various gas conditions. The apparatus consisted of a coal sample cell, a fast pressure unloading system, a monitoring and control system, and a gas filling system. The gas filling system was equipped with safe, explosion-proof solenoid valves for gas pressure unloading and an accurate strain chip for measuring sample strain. The apparatus was designed to probe the influence of the gas on coal and gas outbursts. The study focused on the mechanism by which high-pressure gas influences coal and gas outbursts, leading to the deformation characteristics of the sudden unloading process. The experimental results showed that the plastic deformation of coal samples in the presence of methane gas can be divided into three stages: compression induced by increased pressure, expansion induced by adsorption, and deformation or failure induced by sudden unloading. The results of tests performed in the presence of helium revealed that the deformation could be divided into just two stages: a compression stage induced by increased pressure and a recovery stage induced by sudden pressure unloading. Coal samples were found to deform much more rapidly and to a greater degree in methane than in helium, and the expansive deformation and failure of the coal sample become increasingly apparent with increasing initial gas pressure. Overall, our results demonstrate that the experimental apparatus developed here provides a feasible means to test the characteristics of the coal damage and gas migration that occur during a coal and gas outburst. [ABSTRACT FROM AUTHOR]

Abstract In regions with a relatively complex topography, the soil organic carbon (SOC) is characterized by a high spatial heterogeneity, which is likely to contribute to large uncertainties in the regional SOC estimation. Generally, the elevation and aspect are expected to be the two main topographic controls of the spatial patterns of SOC on steep hillslopes. However, the manner in which the aspect-induced variability in SOC varies with elevation zone is still less understood. In this study, SOC in three elevation-dependent vegetation zones (~2450 m: the shrub-steppe zone, ~2900 m: the forest-steppe zone, and ~3350 m: the shrub-meadow zone) was examined in the Qilian Mountains. Soil samples at 0–10, 10–20, 20–40, and 40–60 cm were collected on the south-, southwest-, west-, northwest-, and north-facing slopes with similar slope gradients (~32°) in each of the three vegetation zones. The results showed that the SOC density tends to increase following the elevation zone, with an average density of about 24.30 kg m−2 at the 0–60 cm. In addition, the SOC concentration appeared to have increased with the cosine of the aspect following an exponential function. The average rate of increase in terms of the aspect at 0–10 cm in the forest-steppe zone was approximately 0.46 g kg−1 degree−1, which amounted to 1.39 and 2.19 fold greater than in the shrub-steppe and shrub-meadow zones, respectively. Path analysis performed using structural equation modelling (SEM) demonstrated that the elevation and the aspect had an indirect influence on the SOC density, through a direct effect on the soil temperature, vegetation type, and soil moisture, and this could possibly explain 88% of the total variation in the SOC density. The present results suggest that the forest-steppe zone is characterized by the strongest aspect effect on SOC in comparison with the shrub-steppe and shrub-meadow zones, and confirm the importance of elevation and aspect in shaping the spatial patterns of SOC. Graphical abstract Unlabelled Image Highlights • SOC increased by elevation with an average density of 24.30 kg m−2. • SOC increased with cosine of aspect following exponential functions. • The forest-steppe zone was characterized by the strongest aspect effect on SOC. • Elevation and aspect together explained 88% of the total variation in SOC. [ABSTRACT FROM AUTHOR]

The loess shoulder‐lines are known to be the most critical topographic structural lines in the loess landform area of the Loess Plateau, China. Previous studies have shown that gully erosion activity can be reflected in the dynamic changes of the shoulder‐lines. In this study, active gully erosion sites along the shoulder‐lines are investigated. Three typical test areas with different loess landforms are selected, and the loess shoulder‐lines are derived from 1 m resolution digital elevation models. First, height profiles of the loess shoulder‐lines are extracted. Then, from the perspective of frequency domains, active gully erosion sites are identified using the Hilbert–Huang transform (HHT). The experimental results show that the HHT method can effectively mine the intrinsic characteristics of the shoulder‐lines. The detailed information components (non‐components) and trend components of the height profiles can be obtained via ensemble empirical mode decomposition and a significance test. In addition, the HHT method was employed to identify the instantaneous frequency curve catastrophe points of the loess shoulder‐line height profiles, and the physical meaning is clear: a higher frequency denotes greater energy and more severe erosive processes, and the catastrophe point locations represent the active gully erosion sites. Evidence from a recent field survey and a comparison with another method supports the results, indicating that the method proposed in this study could potentially be effective for the exploration and analysis of geomorphologically sensitive locations in loess landform studies. [ABSTRACT FROM AUTHOR]

On China's Loess Plateau (CLP), shifts in land use are particularly influential in altering soil microbial communities. While one might expect shifts between grassland, forest and arable land to affect soil microbial communities, the specific ensuing responses of bacterial and fungal diversity and composition on the CLP are poorly understood. Soil microbial diversity and composition among the CLP's native grasslands, afforested lands, and 'abandoned' arable lands (fallow roughly 10 years in 2020) were determined using high-throughput sequencing of 16S rRNA and ITS genes. A comparison of land use types showed the abandonment of arable land and grassland afforestation to have had a negligible impact on soil bacterial α-diversity but to result in significantly lower soil fungal diversity. Grassland afforestation also increased fungal richness. Both bacterial and fungal β-diversity differed significantly among the land uses. Conversion of grassland to abandoned land significantly altered the relative phylum-level abundance of bacteria (except that of the Acidobacteria), but not that of fungal phyla. Grassland afforestation only influenced the abundance of bacteria and fungi of lower relative abundance (<10 % except Proteobacteria). The quantity of above- and below-ground biomass and soil properties explained most of the variation in soil microbial communities. Having important ecological implications, these findings can inform land management decisions in the study area and similar ecologically-fragile regions. • Grassland conversions altered soil fungal but not bacterial α-diversity. • Grassland conversions affected soil microbial β-diversity. • Grassland converted to abandoned land remarkably changed soil bacterial composition. • Grassland afforestation only affected bacteria and fungi with low relative abundance. • Soil texture played a crucial role in altering soil microbial β-diversity. [ABSTRACT FROM AUTHOR]

Gully feature mapping is an indispensable prerequisite for the motioning and control of gully erosion which is a widespread natural hazard. The increasing availability of high-resolution Digital Elevation Model (DEM) and remote sensing imagery, combined with developed object-based methods enables automatic gully feature mapping. But still few studies have specifically focused on gully feature mapping on different scales. In this study, an object-based approach to two-level gully feature mapping, including gully-affected areas and bank gullies, was developed and tested on 1-m DEM and Worldview-3 imagery of a catchment in the Chinese Loess Plateau. The methodology includes a sequence of data preparation, image segmentation, metric calculation, and random forest based classification. The results of the two-level mapping were based on a random forest model after investigating the effects of feature selection and class-imbalance problem. Results show that the segmentation strategy adopted in this paper which considers the topographic information and optimal parameter combination can improve the segmentation results. The distribution of the gully-affected area is closely related to topographic information, however, the spectral features are more dominant for bank gully mapping. The highest overall accuracy of the gully-affected area mapping was 93.06% with four topographic features. The highest overall accuracy of bank gully mapping is 78.5% when all features are adopted. The proposed approach is a creditable option for hierarchical mapping of gully feature information, which is suitable for the application in hily Loess Plateau region. [ABSTRACT FROM AUTHOR]

Soils in alpine regions associated with complex topography are characterized by large variability in the spatial distribution of soil organic carbon (SOC). However, the patterns and topographic controls on SOC at the hill scale in semiarid alpine regions are not well understood. In this study, the effects of slope aspects and depths on SOC were quantified based on field investigations in a mainly undisturbed region of the Qilian Mountains in northwestern China. Soil samples were collected at 0–10, 10–20, 20–40 and 40–60 cm on south-, southwest-, west-, and north-facing slopes of three hills. Results showed that the SOC density at 0–60 cm varied from 9.73 to 35.21 kg m − 2 , and increased from the south- to north-facing slopes. The average SOC density on the north-facing slopes was about 3.2, 2.9 and 1.9 times larger than on the south-, southwest- and west-facing slopes. Both the general linear model and mixed linear model suggested that, at the hill scale, the slope aspects and soil depths explained the main variations of SOC concentration in our study. The profile pedotransfer function method indicated that the SOC varied predictably with soil depths and aspects, and the prediction functions well predicted the SOC data from literature. Our results highlight the importance of slope aspect as an indicator of the SOC, and demonstrate that the transformed aspect is a good continuous variable in predicting the SOC in the semiarid alpine region. [ABSTRACT FROM AUTHOR]

Topography has an influence on both abiotic (e.g. soil) and biotic (e.g. vegetation) factors influencing soil organic carbon (SOC). In this study, three slope aspects, south-facing, semi-sunny (south-west), and semi-shady (north-west) of mountainous grassland in the middle of the Qilian Mountains were sampled to explore the variation in SOC caused by topography. Soil properties were analyzed at different depths (0–10, 10–20, 20–40, and 40–60 cm). The results showed that except soil total organic phosphate, SOC, soil water content, soil bulk density, daily soil temperature, biomass, vegetation cover, and species richness on the semi-shady slope aspect were significantly different to those on two other slope aspects. The SOC, vegetation cover, and biomass significantly increased, from the south-facing to semi-shady slope aspect, and their values on the semi-shady slope aspect were around two times greater than on the south-facing slope aspect. The plant community composition also varied by slope aspect, with Agropyron cristatum and Stipa grandis dominant on the south-facing slope aspect, and Agropyron cristatum and Carex aridula dominant on the semi-sunny slope aspect, and Kobresia humilis and Carex crebra dominant on the semi-shady slope aspect. Among all measured abiotic and biotic factors, daily soil temperature, soil bulk density and total soil organic nitrogen could be used to predict SOC, explaining 69.0% of the variation in the data ( p < 0.001). On all slope aspects, SOC was greatest in the top 20 cm of soil, representing around 60.0% of the total SOC to 60 cm depth. The results indicated that the distribution of SOC was regulated by slope aspect through its influence on vegetation and soil properties in this region. Therefore, SOC protection measures should be aspect specific. [ABSTRACT FROM AUTHOR]

[Display omitted] • Large-scale uniform plasmonic gratings were fabricated by laser processing. • The depth of the silicon grating can be controlled by the chemical etching time. • The gold–silicon grating can efficiently excite surface plasmon resonance. • The sensitivity and resolution of the SPR sensor are 707.4 nm/RIU and 0.00053 RIU. • The SPR sensor was applied to monitor BSA solutions in real time. Surface plasmon resonance (SPR) sensors based on nanostructures have received much attention in recent years for constructing portable devices. A main barrier for their widespread use is that traditional nanofabrication methods are expensive and time-consuming. Here, we demonstrate a mask-free, low-cost and high-production method to fabricate large-scale uniform plasmonic gratings with variable depths. Regular amorphous silicon strips were firstly triggered on the silicon surface via scanning by a cylindrically focused femtosecond laser. Subsequently, the laser processed silicon was etched by alkaline to form highly regular gratings, whose depth is flexible to be adjusted by controlling the etching time. After depositing a 53 nm gold film, the fabricated plasmonic gratings are able to efficiently generate SPR absorption dips as observed in the reflection spectra. Moreover, a SPR sensor was built based on the optimal grating, which has a sensitivity of 707.4 nm/RIU, a figure of merit of 13.37 RIU−1 and a refractive index resolution of 5.3 × 10 - 4 RIU. The combination process of bovine serum albumin and the gold grating was also studied. The fabrication method introduced here paves the way for mass-production of high-quality plasmonic gratings. The SPR sensor can be potentially used in applications like medical diagnoses, biotechnology, security and food safety. [ABSTRACT FROM AUTHOR]

Grating coupled surface plasmon resonance (GC-SPR) sensors are widely used in analyzing gases, aqueous solutions, proteins and environmental pollutants. However, traditional GC-SPR sensors are difficult to detect absorptive fluids because the spectra of the light will be distorted after passing through the absorptive fluids. Here, we propose and experimentally demonstrate a backside illuminated GC-SPR (BIGC-SPR) sensor, where the light is incident from the transparent substrate side of the sensor chip. The grating chip is fabricated by a simple and cost-effective procedure. DVD-R disc is used as a template to imprint the grating structure onto a polydimethylsiloxane (PDMS) substrate, then a thin Au layer of 35 nm thickness is evaporated on it. By calibrating the sensor with glucose solutions, the sensitivity and refractive index resolution are measured to be 311.97 nm/RIU and 0.00043 RIU, respectively. Moreover, the BIGC-SPR sensor is demonstrated to monitor the concentration of blue engine coolant, green antirust cutting fluid and white antirust emulsified oil solutions. The designed sensor is able to detect colored or highly scattering solutions, and can be potentially used in the fields of medical diagnosis, environmental monitoring and biological protein detection. [Display omitted] • A backside illuminated grating coupled SPR sensor was introduced. • Nanoimprint was applied as a cost effective method to fabricate Au-PDMS gratings. • The designed SPR sensor was demonstrated to detect absorptive fluids. • The sensitivity and resolution of the sensor are 311.97 nm/RIU and 0.00043 RIU. [ABSTRACT FROM AUTHOR]

Terraces, which are typical artificial landforms found around world, are of great importance for agricultural production and soil and water conservation. However, due to the lack of maintenance, terrace damages often occur and affect the local flow process, which will influence soil erosion. Automatic high-accuracy mapping of terrace damages is the basis of monitoring and related studies. Researchers have achieved artificial terrace damage mapping mainly via manual field investigation, but an automatic method is still lacking. In this study, given the success of high-resolution unmanned aerial vehicle (UAV) photogrammetry and object-based image analysis (OBIA) for image processing tasks, an integrated framework based on OBIA and UAV photogrammetry is proposed for terrace damage mapping. The Pujiawa terrace in the Loess Plateau of China was selected as the study area. Firstly, the segmentation process was optimised by considering the spectral features and the terrains and corresponding textures obtained from high-resolution images and digital surface models. The feature selection was implemented via correlation analysis, and the optimised segmentation parameter was achieved using the estimation of scale parameter algorithm. Then, a supervised k-nearest neighbourhood classifier was used to identify the terrace damages in the segmented objects, and additional geometric features at the object level were considered for classification. The comparison with the ground truth, as delineated by the image and field survey, showed that proposed classification can be adequately performed. The F-measures of extraction on three terrace damages were 92.07% (terrace sinkhole), 81.95% (ridge sinkhole), and 85.17% (collapse), and the Kappa coefficient was 85.34%. Finally, the potential application and spatial distribution of the terrace damages in this study were determined. We believe that this work can provide a credible framework for mapping terrace damages in the Loess Plateau of China. [ABSTRACT FROM AUTHOR]

Ultraviolet lenses are core components of surveillance cameras, lithography machines and UV microscopes. Traditional refractive UV lenses are bulky, expensive and easy to aging, which hinders their applications in miniaturized and integrated photonic devices. In this paper, we proposed a polarization independent, broadband achromatic metalens that consists of arrays of silicon nitride nanopillars on a flat substrate. In order to simultaneously fulfill the target phases in a wide spectrum range, the phase library is extended to 0-8 π by using tall nanopillars that support high order resonances. The designed metalens has a stable focus across the entire operating wavelength range from 300 nm to 400 nm and the average focusing efficiency is as high as 50%. This polarization independent achromatic metalens can be potentially applied in compact UV cameras, UV microscopes and lithography machines. • The designed metalens has a stable focus in wavelength range of 300 to 400 nm. • The achromatic metalens is insensitive to the polarization of the incident light. • The average focusing efficiency is as high as 50%. • The focus spots are close to the diffraction limit in the entire operating wavelength range. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we analyze market efficiency for the Shanghai stock market over time using a model-free method known as multifractal detrended fluctuation analysis. Through analyzing the change of scale behavior, we find that the price-limited reform improved the efficiency in the long term, but the influence in the short term was very minor. Employing the method of moving window, using three different measures we find that the Shanghai stock market became more and more efficient after the reform. We also implement the same procedure on volatility series and find the evidence of inefficiency. [Copyright &y& Elsevier]