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Explaining the mechanisms underlying spatial and temporal variation in community composition is a major challenge. Nevertheless, the processes controlling temporal variation at a site (i.e. temporal β‐diversity, including its turnover and nestedness components) are less understood than those affecting variation among sites (i.e. spatial β‐diversity). Short‐term temporal turnover (e.g. throughout an annual cycle) is expected to correlate positively with seasonal environmental variability and landscape connectivity, but also species pool size (γ‐diversity). We use the megadiverse Amazonian freshwater ichthyofauna as a model to ask whether seasonality and landscape connectivity drive variation in temporal species turnover among geomorphological habitat types, while accounting for between‐habitat variation in γ‐diversity. We collected 11 397 fish representing 260 species during a year‐long sampling program from an area containing the lowland Amazon's four major geomorphological habitat types: rivers, floodplains, terra firme streams, and shield streams. River‐floodplain systems exhibit strong but predictable seasonality (via a high‐amplitude annual flood pulse), high connectivity, and high species richness with many rare species. Terra firme and shield streams exhibit low seasonality, low connectivity, and low species richness with proportionally fewer rare species. Based on these parameters we predicted that river‐floodplain systems should have higher temporal turnover than stream systems. Using a null model approach combined with β‐deviation calculations, we confirmed that rivers and floodplains do exhibit higher turnover (but not nestedness) than terra firme and shield streams, even when controlling for the potentially confounding effect of higher species richness in river‐floodplain systems. All habitats exhibit low temporal nestedness, indicating that short‐term changes in community composition result primarily from temporal species turnover. Our results provide a timely reminder that efforts to conserve the Amazon's threatened aquatic biodiversity should account for the distinct temporal dynamics of habitat types and variation in hydrological seasonality. [ABSTRACT FROM AUTHOR]

Community ecology has so far struggled to integrate both deterministic and stochastic processes into a global model of community variation. To address this issue, we aimed to characterise the ecological conditions that determine the relative importance of deterministic and stochastic community variation in benthic macroinvertebrates. We sampled macroinvertebrate and algal periphyton communities, and microhabitat conditions at monthly intervals over a five year period in two sampling sites in the regulated Durance River and one site in the Asse River (a natural tributary of the Durance). The relative importance of stochastic and deterministic processes was estimated over time as functional and taxonomic spatial β‐deviation (i.e. β‐diversityobs − mean β‐diversitynull/SD β‐diversitynull) for each sampling date and site. We additionally quantified deterministic variation as the trait–environment relationship and predicted a positive correlation with β‐deviation metrics. We found evidence of overdispersal in both functional and taxonomic β‐diversities compared to null expectations. Spatial β‐deviation was highly variable over temporal scales and was jointly explained by invertebrate community size, disturbance (i.e. flooding), periphyton diversity and to a lesser extent, microhabitat diversity. The key factor that explained β‐deviation was recent river discharge (< 90 days), which had a strong negative effect on community size but was also directly associated with higher β‐deviation, likely related to recolonization processes post‐flood. Lastly, we found that when β‐deviation was high, the hydraulic trait–environment relationship was stronger. This indicates that spatial heterogeneity in hydraulic conditions was the main driver of deterministic variation in invertebrate community structure. This study demonstrates that the importance of stochastic processes can vary greatly over short (~ months) and long (~ years) temporal windows with significant consequences for trait–environment relationships. Our study provides an example of how stochastic community variation can be modelled to better interpret deterministic patterns of community structure in natural communities. [ABSTRACT FROM AUTHOR]

Increased atmospheric nitrogen (N) deposition affects biodiversity in terrestrial ecosystems. However, we do not know whether the effects of N on above‐ground plant β‐diversity are coupled with changes occurring in the soil seed bank. We conducted a long‐term N‐addition experiment in a typical steppe and found that above‐ground β‐diversity increased and then decreased with increasing N addition, whereas below‐ground β‐diversity decreased linearly. This suggests decoupled dynamics of plant communities and their soil seed bank under N enrichment. Species substitution determined above‐ and below‐ground β‐diversity change via an increasing role of deterministic processes with N addition. These effects were mostly driven by differential responses of the above‐ground vegetation and the soil seed bank β‐diversities to N‐induced changes in environmental heterogeneity, increased soil inorganic N concentrations and soil acidification. Our findings highlight the importance of considering above‐ and below‐ground processes simultaneously for effectively conserving grassland ecosystems under N enrichment. [ABSTRACT FROM AUTHOR]

Soil biodiversity plays a critical role in supporting multiple ecosystem functions. As some of the most diverse and abundant metazoans on the Earth, soil nematode communities exhibit changes along environmental gradients, but the ways in which the abundance and diversity of nematode communities vary along elevational gradients remain poorly understood. Taking advantage of an investigation on Huangshan Mountain, Southeast China, with elevation ranging from 500 to 1200 m, we assessed the abundance and diversity of soil nematodes, as well as the soil physicochemical properties, across subtropical forest ecosystems. Nematode communities were analyzed at the genus level, and the α-diversity was calculated as the genus richness, while the β-diversity was based on the Bray–Curtis dissimilarity. The results showed that, among the top 20 nematode genera ranked by absolute abundance, most genera, such as Eucephalobus, Prismatolaimus, Filenchus, and Rotylenchulus, reached their peak abundance at the highest elevation (1000 m). Additionally, the abundances of Oriverutus, Tylenchus, Criconema, and Tripyla exhibited a positive correlation with the elevation. Moreover, the abundance and α-diversity of the total nematodes and each trophic group of nematodes increased linearly with the elevation, likely due to increased soil moisture at higher elevation. In contrast, the β-diversity of the total nematodes, bacterivores, and herbivores decreased with increasing elevation, indicating the importance of stochastic processes in shaping community assembly at high altitudes. This pattern suggests that as the elevation increases, the nematode communities become more homogeneous in structure. Taken together, our study's findings demonstrate the divergent responses of nematodes' α- and β-diversity to an elevation gradient, highlighting the importance of the soil nematode diversity in maintaining ecosystem functions such as nutrient cycling and food web stability in mountainous regions. These results emphasize the need to incorporate the below-ground biodiversity into conservation strategies, particularly in the face of environmental changes driven by climate and human activities. [ABSTRACT FROM AUTHOR]

Both regional species pool and local community assembly mechanism drive the microbial diversity patterns across geographical gradients. However, little has been done to separate their effects on the β diversity patterns of microbial communities involved in nitrogen (N) cycling in river ecosystems. Here, we use high‐throughput sequencing of the archaeal amoA, bacterial amoA, nirK, and nirS genes, null model, and neutral community model to distinguish the relative importance of species pool and local assembly processes for ammonia‐oxidizing and denitrifying communities in river wetlands along a latitudinal gradient in eastern China. Results indicated that the β diversity of the nirS‐type denitrifying community co‐varied with γ diversity and environmental heterogeneity, implying that regional species pool and heterogeneous selection explained variation in β diversity. However, the β diversity of ammonia‐oxidizing and nirK‐type denitrifying communities did not correlate with γ diversity and environmental heterogeneity. The continuous hump distribution of β deviation along the latitudinal gradient and the lower species dispersal rate indicated that the dispersal limitation shaped the variation in β diversity of ammonia‐oxidizing and nirK‐type denitrifying communities. Additionally, biotic interactions drove ammonia‐oxidizing and nirS‐type denitrifying communities by influencing species co‐occurrence patterns. Our study highlights the importance of regional species pool and local community assembly processes in shaping geographical patterns of N‐cycling microorganisms and extends knowledge of their adaptability to a continuously changing environment on a large scale. [ABSTRACT FROM AUTHOR]

The effect of the metallic layer thickness on the stress-strain state and strength of thick-walled metal-composite cylinders of total constant thickness under internal dynamic pressure produced by the explosion of a charge uniformly distributed along its axis in air at the constant total-to-running charge mass ratio ξ = 1.421 mm was numerically investigated. The strength of the cylinders was evaluated by the generalized Mises criterion. It is numerically and analytically proved that the strength of circularly reinforced cylinders from the composites of low tensile strength in the isotropy plane is primarily governed by the wave processes across the shell width and, as a consequence, by radial and axial tensile stresses, viz the larger they are, the lower the strength. Circumferential tensile stresses, on the contrary, improve the strength in most cases, i.e., only strengthen the structural element and increase the safety margin. Cylinders with four outer layer composites are examined. They are double-layered: the inner layer is steel (St20), the outer layer is a circularly reinforced composite. At given ξ and the total constant cylinder thickness H , the optimum in strength terms ratio β opt of the metallic layer thickness h to H is strongly dependent on a composite (i.e., its physicomechanical characteristics) and varies within 0.3–0.7. The plastic deformation of the inner steel layer has a significant impact on the shell strength, the account of the plastic steel deformation substantially changes the dynamics of objects both qualitatively and quantitatively, thus, the strength function can be reduced by more than 50% compared to the elastic calculation. The strength of metal-composite cylinders is proved to be very sensitive to the wave phenomena along the radial coordinate. Sometimes at a certain ratio of layers β (about 0.7), the charge mass ratio ξ (and hence the absolute charge mass M ) can be increased more than twice without deterioration of the strength requirements, while the β deviation by only 1.5% from that at given ξ would lead to the cylinder fracture. [ABSTRACT FROM AUTHOR]

Summary: In this study, we investigated microbial communities (bacteria and protist) in two coastal areas near the estuaries of the Liaohe (LH) River and Yalujiang (YLJ) River in the Northwestern Pacific Ocean. Due to the existence of Liaodong Peninsula and different levels of urbanization, geographical segregation and significant environmental heterogeneity were observed between these two areas. There were significantly different regional species pools and biogeographic patterns for both bacterial and protistan communities between LH and YLJ coastal areas. Species turnover was the main mechanism driving β‐diversity patterns of both bacterial and protistan communities in each area. In addition, the contributed ratio of nestedness to the β‐diversity patterns was significantly higher for protists compared to bacteria. Variation in regional species pools was found to be the dominant driver of differences of bacterial and protistan communities between the LH and YLJ coastal areas. For a single‐studied area, local community assembly mechanisms, including heterogeneous selection and dispersal limitation, were found to shape the bacterial and protistan communities through calculation of the β‐deviation index. Among them, the relative importance of heterogeneous selection and dispersal limitation on the community assembly varied according to microorganism type and habitat. [ABSTRACT FROM AUTHOR]

Grassland degradation caused by increases in livestock grazing threatens a variety of ecosystem services. Understanding changes in plant community assembly during the process of grassland degradation in the presence of grazing is important to help restore degraded grasslands worldwide but has received little attention thus far. The grassland degradation process is typified by heterogeneous degradation, that is, gradual formation of degraded patches (hereafter "patchy degradation"). Here, we experimentally examined the effects of herbivore grazing and patchy degradation on plant community assembly using nine pairs of non‐degraded (intact) and patch‐degraded (fragmented) grasslands subject to grazing by different‐sized herbivores (i.e., NG, no grazing; SG, sheep grazing; CG, cattle grazing) over 4 years. Using a null‐model approach, we estimated the relative magnitude of deterministic processes of community assembly by comparing the observed and expected β‐diversity. We found that in the absence of herbivore grazing, deterministic processes played a greater role in community assembly, regardless of whether patchy degradation had occurred. However, the deterministic processes resulted in plant communities being more spatially similar in non‐degraded grasslands while being more dissimilar in patchy degraded grasslands. Compared with non‐degraded grasslands, species with strong competitive abilities (i.e., Leymus chinensis) were less dominant in patchy degraded grasslands, indicating relaxed competition and a reduced role of species interactions over plant communities. Instead, patchy degradation added the role of environmental variables over plant communities. SG consistently promoted more stochastic plant community assembly in both non‐degraded and patch‐degraded grasslands, while CG promoted more stochastic plant community assembly only in the non‐degraded state, having no effect in the patch‐degraded state. Our study offers important insights into changes in plant community assembly during ongoing patch‐degradation of grasslands, indicating the role of increased environmental filtering of soil and reduced species interactions in driving plant community dynamics with increasing grassland patchy degradation. We also uncovered an herbivore species‐specific effect on plant community assembly during the process of grassland degradation, which will better inform and improve future grassland restoration planning efforts. [ABSTRACT FROM AUTHOR]

The tendency of relative motion via rolling between contacting objects exists in various aspects of industry and nature because, in many practical situations, forces and moments may be simultaneously induced at the contacting interfaces. Due to the presence of adhesion, which may be prominent on small scales, research on contacts with the tendency to roll, termed herein as rolling adhesion, is very limited. In the present work, a novel double-Hertz model is developed for adhesive contact between spherical objects subjected to the combined action of normal forces and moments. The results from the new model agree well with available numerical simulations and experimental results. It has been demonstrated that the contact behavior with the effect of rolling adhesion seemingly resembles that of conventional adhesive contact, but the applied moment may impact the pull-off force and may even induce novel contact instability if large enough. The resistance moment at the interface has also been obtained analytically, which is proportional to adhesion hysteresis and contact area. Given the applicability to the full range of the Tabor parameter and nonsingular stresses involved, these results might shed light on adhesive contacts with rolling adhesion and help to characterize them better than existent models. [ABSTRACT FROM AUTHOR]

Geminiviridae are ssDNA plant viruses whose control has both economical and agricultural importance. Their capsids assemble into two distinct architectural forms: (i) a T = 1 icosahedral and (ii) a unique twinned quasi-isometric capsid. Described here are the high-resolution structures of both forms of the maize streak virus using cryo-EM. A comparison of these two forms provides details of the coat protein (CP) and CP–CP and CP–genome interactions that govern the assembly of the architecture of the capsids. Comparative analysis of other representative members of Geminiviridae reveals structural conservation of 60–95% compared to a sequence similarity of 21–30%. This study provides a structural atlas of these plant pathogens and suggests possible antiviral-targetable regions of these capsids. [ABSTRACT FROM AUTHOR]

Understanding how and why β‐diversity varies along latitude is a long‐standing challenge in community ecology and rarely addressed in both space and time. We aimed to explore the spatiotemporal variations in macroinvertebrate β‐diversity and their underlying drivers in eight biogeographic regions covering a substantial latitudinal gradient of more than 40 degrees. By combining β‐diversity partitioning and distance decay of community similarity analyses, we found that subtropical β‐diversity varies more in space relative to variation in time compared with temperate β‐diversity, as we predicted. This is probably because subtropical β‐diversity is shaped by species–environment sorting (SS), caused by habitat heterogeneity and species specialization, more strongly in space relative to time than temperate β‐diversity. Our study highlights the importance of SS in shaping latitudinal gradients of β‐diversity in space and time. [ABSTRACT FROM AUTHOR]

The climate and soil properties are major determinants of plant growth and forest community assembly across diverse biomes. However, the contribution of climate and soil on species diversity in tropical and subtropical forests remains controversial. Therefore, this study aims to evaluate the effects of soil and climate on tree species richness using survey data across 495 tropical and subtropical forest plots in Southern China. The selected predictors were categorized as local plot characteristics, climate, and soil factors, and their relationship with tree species richness was modeled using negative binomial generalized linear models. The results revealed that the considering of the interaction between climate and soil properties considerably improved the goodness−of−fit of these models. The individual effects of climate and soil factors had weak relationships with species richness, accounting for 3.61% and 5.77% of the overall 58.9% explained variance in species richness, respectively. Instead, the interaction between climate and soil properties explained most of the statistical variation in tree species richness (84.34% of the overall 58.9% explained variance). The results highlight the importance of soil and climate interactions on tree diversity in tropical and subtropical mature natural forests and their incorporation into biodiversity assessment models to enhance the prediction of community change and responses to climate change. [ABSTRACT FROM AUTHOR]

Spiroplasma virus 4 (SpV4) is a bacteriophage of the Microviridae, which packages circular ssDNA within non-enveloped T = 1 icosahedral capsids. It infects spiroplasmas, which are known pathogens of honeybees. Here, the structure of the SpV4 virion is determined using cryo-electron microscopy to a resolution of 2.5 Å. A striking feature of the SpV4 capsid is the mushroom-like protrusions at the 3-fold axes, which is common among all members of the subfamily Gokushovirinae. While the function of the protrusion is currently unknown, this feature varies widely in this subfamily and is therefore possibly an adaptation for host recognition. Furthermore, on the interior of the SpV4 capsid, the location of DNA-binding protein VP8 was identified and shown to have low structural conservation to the capsids of other viruses in the family. The structural characterization of SpV4 will aid future studies analyzing the virus–host interaction, to understand disease mechanisms at a molecular level. Furthermore, the structural comparisons in this study, including a low-resolution structure of the chlamydia phage 2, provide an overview of the structural repertoire of the viruses in this family that infect various bacterial hosts, which in turn infect a wide range of animals and plants. [ABSTRACT FROM AUTHOR]

The zoonotic viruses pose significant threats to public health. Nipah virus (NiV) is an emerging virus transmitted from bats to humans. The NiV causes severe encephalitis and acute respiratory distress syndrome, leading to high mortality rates, with fatality rates ranging from 40% to 75%. The first emergence of the disease was found in Malaysia in 1998–1999 and later in Bangladesh, Cambodia, Timor‐Leste, Indonesia, Singapore, Papua New Guinea, Vietnam, Thailand, India, and other South and Southeast Asian nations. Currently, no specific vaccines or antiviral drugs are available. The potential advantages of epitope‐based vaccines include their ability to elicit specific immune responses while minimizing potential side effects. The epitopes have been identified from the conserved region of viral proteins obtained from the UniProt database. The selection of conserved epitopes involves analyzing the genetic sequences of various viral strains. The present study identified two B cell epitopes, seven cytotoxic T lymphocyte (CTL) epitopes, and seven helper T lymphocyte (HTL) epitope interactions from the NiV proteomic inventory. The antigenic and physiological properties of retrieved protein were analyzed using online servers ToxinPred, VaxiJen v2.0, and AllerTOP. The final vaccine candidate has a total combined coverage range of 80.53%. The tertiary structure of the constructed vaccine was optimized, and its stability was confirmed with the help of molecular simulation. Molecular docking was performed to check the binding affinity and binding energy of the constructed vaccine with TLR‐3 and TLR‐5. Codon optimization was performed in the constructed vaccine within the Escherichia coli K12 strain, to eliminate the danger of codon bias. However, these findings must require further validation to assess their effectiveness and safety. The development of vaccines and therapeutic approaches for virus infection is an ongoing area of research, and it may take time before effective interventions are available for clinical use. [ABSTRACT FROM AUTHOR]

In this study, the results are presented and discussed from laboratory test campaigns specifically designed to investigate the behavior of sacrificial piles as a countermeasure against local scouring at a circular bridge pier and clear-water conditions with flow intensity slightly below the threshold of sediment motion. Sacrificial piles are assessed on the upstream side of the pier in two transverse and triangular arrangements. Piles can reduce scouring by deflecting the flow and creating a low-velocity wake region behind them. The efficiency of the piles against local scouring depends on the diameter of the piles, the number of piles, and the angle of the wedge. The investigation was aimed at evaluating the effectiveness of the sacrificial piles as a function of different dimensionless groups. It was found that the triangular arrangement of sacrificial piles has better results than the transverse arrangement. The results showed that the triangular sacrificial piles reduced the maximum local scour depth at the pier to 37.2% in the best configuration. Combined countermeasures were tested, which were composed of sacrificial piles and a bed sill downstream of the pier; in the best configuration, the scour depth reduction in front of the pier reached 51.1%. The increased efficiency of the combination of bed sill and sacrificial piles (BSSP) is an advantage that can reduce the risk of pier failure when the duration of the flood is short. This last result shows that a combination of BSSP may be a very effective countermeasure against local scouring at bridge piers. Finally, the coherent turbulent flow structure around the best combination of BSSP was investigated, and its effect on the bed scouring pattern was studied. A 3D analysis of the bursting process was used. Turbulence characteristics, as well as the occurrence and transition probabilities of bursting events, were calculated. The obtained results confirmed the quite effective effect of the combination of these two countermeasures in reducing the scour depth. [ABSTRACT FROM AUTHOR]

This study investigates the experimental and analytical torsional behavior of reinforced concrete (RC) bridge box girders reinforced with glass fiber–reinforced polymer (GFRP) bars and continuous spiral stirrups, representing a first in literature. Reinforced concrete box girders were constructed and examined until failure to assess the influence of the spiral pitch and web reinforcement configuration on torsional behavior and strength. The test specimens had continuous GFRP spirals and tie stirrups; the control specimen did not have web reinforcement. The specimens were 4,000 mm long, 380 mm wide, and 380 mm high, and had a wall thickness of 100 mm. The test results demonstrate that the box girder with spiral GFRP reinforcement achieved higher torsional strength and lower twist than its counterpart specimen reinforced with individual GFRP tie stirrups by approximately 6% and 11%, respectively. The specimen with a narrow spiral pitch performed better than the specimens with a wide spiral pitch. An analytical iterative softened membrane model for torsion (SMMT) was used to estimate the entire torsional behavior of box girders with spiral GFRP reinforcement. The analytical results were compared with the experimental results of four bridge box girders with spiral GFRP reinforcement to validate the model's accuracy. The comparison indicates that the model could reasonably predict the cracking and ultimate torsional strength as well as the associated twists. [ABSTRACT FROM AUTHOR]

The way of approaching the flood hazard in the Dobrogea Hydrographic Area consists in a first phase in the grouping of registered water courses on three levels of detail according to the frequency of floods in recent years, their amplitude, the form of manifestation, the degree of equipping with works of defence against floods, social or economic objectives subject to flood hazard. The causes of these floods were the amounts of precipitation from torrential rains recorded in a certain period of time. Due to the flood waves, the danger levels were exceeded, some sectors of the permanently flowing watercourses were flooded. In Nuntași, between 02.09-04.09.1999, the flood produced on the Nuntaşi river destroyed houses, cultures, lives, etc. The assessment of the water resources in this basin consists in the assessment of the hydrographic and hydrogeological basins, which together form the reception basin. surface, shape, hypsometric curve and average altitude of the basin, average slope, vegetation cover, hydrogeological basin, hydrograph, rainfall hyetogram, etc.) The risk analysis of the NUNTAȘI hydrographic space consists in the measurement and quantification of 4 parameters using the RkFMEA method (RisK Failure Mode Evaluation Analysis): vulnerability (exposure) (R), probability (P), the effect of the existence of a control instrument/measure/control/action (N) and the efficiency indicator of a new measure (F). The simple risk level (RPN factor) and the efficiency factor F (complex risk level, RPNF) were automatically calculated. The conclusion of the risk analysis was: the NUNTAȘI bed falls under "low risk with serious prevention measure without any urgent implementation with RPNF values between (1...150)". [ABSTRACT FROM AUTHOR]

In order to ensure the lateral stability of adaptive cruise control (ACC) vehicles during curve following, this paper proposes a hierarchical multi‐objective coordinated control ACC system structure for in‐wheel motor drive electric vehicles. Different control strategies are designed for the cruise mode and car‐following mode of the ACC system. A proportion integral differential (PID) controller is used to meet the need for speed control in cruise mode. For the car‐following mode, a multi‐objective ACC system distance control strategy is proposed considering the performance of car following, passenger comfort, driving safety and driving economy of ACC vehicles. The weight coefficients in the objective function are updated in real time by using the fuzzy model predictive control (FMPC) strategy to meet the needs of different road conditions and improve the driving economy. Then, the desired front wheel steering angle is obtained by preview control theory. According to the theory of sliding mode control (SMC), a lateral stability controller is designed to track the desired yaw rate and sideslip angle. Simulation results show that the electric vehicle driven by in‐wheel motors based on FMPC and SMC has better car‐following performance and lateral stability performance under variable curvature curved road conditions. [ABSTRACT FROM AUTHOR]

Root‐centric studies have revealed fast taxonomic turnover across root neighborhoods, but how such turnover is accompanied by changes in species functions and phylogeny (i.e., β diversity) remains largely unknown. As β diversity can reflect the degree of community‐wide biotic homogenization, such information is crucial for better inference of below‐ground assembly rules, community structuring, and ecosystem processes. We collected 2480 root segments from 625 0–30 cm soil profiles in a subtropical forest in China. Root segments were identified into 138 species with DNA‐barcoding with six root morphological and architectural traits measured per species. By using the mean pairwise (Dpw) and mean nearest neighbor distance (Dnn) to quantify species ecological differences, we first tested the non‐random functional and phylogenetic turnover of root neighborhoods that would lend more support to deterministic over stochastic community assembly processes. Additionally, we examined the distance‐decay pattern of β diversity, and finally partitioned β diversity into geographical and environmental components to infer their potential drivers of environmental filtering, dispersal limitation, and biotic interactions. We found that functional turnover was often lower than expected given the taxonomic turnover, whereas phylogenetic turnover was often higher than expected. Phylogenetic Dpw (e.g., interfamily species) turnover exhibited a distance‐decay pattern, likely reflecting limited dispersal or abiotic filtering that leads to the spatial aggregation of specific plant lineages. Conversely, both functional and phylogenetic Dnn (e.g., intrageneric species) exhibited an inverted distance‐decay pattern, likely reflecting strong biotic interactions among spatially and phylogenetically close species leading to phylogenetic and functional divergence. While the spatial distance was generally a better predictor of β diversity than environmental distance, the joint effect of environmental and spatial distance usually overrode their respective pure effects. These findings suggest that root neighborhood functional homogeneity may somewhat increase forest resilience after disturbance by exhibiting an insurance effect. Likewise, root neighborhood phylogenetic heterogeneity may enhance plant fitness by hindering the transmission of host‐specific pathogens through root networks or by promoting interspecific niche complementarity not captured by species functions. Our study highlights the potential role of root‐centric β diversity in mediating community structures and functions largely ignored in previous studies. [ABSTRACT FROM AUTHOR]

The application of abruptly enlarged flows to adjust the drag of aerodynamic vehicles using machine learning models has not been investigated previously. The process variables (Mach number (M), nozzle pressure ratio (η), area ratio (α), and length to diameter ratio (γ )) were numerically explored to address several aspects of this process, namely base pressure (β) and base pressure with cavity (βcav). In this work, the optimal base pressure is determined using the PCA-BAS-ENN based algorithm to modify the base pressure presetting accuracy, thereby regulating the base drag required for smooth flow of aerodynamic vehicles. Based on the identical dataset, the GA-BP and PSO-BP algorithms are also compared to the PCA-BAS-ENN algorithm. The data for training and testing the algorithms was derived using the regression equation developed using the Box-Behnken Design (BBD). The results show that the PCA-BAS-ENN model delivered highly accurate predictions when compared to the other two models. As a result, the advantages of these results are two-fold, providing: (i) a detailed examination of the efficiency of different neural network algorithms in dealing with a genuine aerodynamic problem, and (ii) helpful insights for regulating process variables to improve technological, operational, and financial factors, simultaneously. [ABSTRACT FROM AUTHOR]

Based on sampling data, we propose a rigorous standardization method to measure and compare beta diversity across datasets. Here beta diversity, which quantifies the extent of among‐assemblage differentiation, relies on Whittaker's original multiplicative decomposition scheme, but we use Hill numbers for any diversity order q ≥ 0. Richness‐based beta diversity (q = 0) quantifies the extent of species identity shift, whereas abundance‐based (q > 0) beta diversity also quantifies the extent of difference among assemblages in species abundance. We adopt and define the assumptions of a statistical sampling model as the foundation for our approach, treating sampling data as a representative sample taken from an assemblage. The approach makes a clear distinction between the theoretical assemblage level (unknown properties/parameters of the assemblage) and the sampling data level (empirical/observed statistics computed from data). At the assemblage level, beta diversity for N assemblages reflects the interacting effect of the species abundance distribution and spatial/temporal aggregation of individuals in the assemblage. Under independent sampling, observed beta (= gamma/alpha) diversity depends not only on among‐assemblage differentiation but also on sampling effort/completeness, which in turn induces dependence of beta on alpha and gamma diversity. How to remove the dependence of richness‐based beta diversity on its gamma component (species pool) has been intensely debated. Our approach is to standardize gamma and alpha based on sample coverage (an objective measure of sample completeness). For a single assemblage, the iNEXT method was developed, through interpolation (rarefaction) and extrapolation with Hill numbers, to standardize samples by sampling effort/completeness. Here we adapt the iNEXT standardization to alpha and gamma diversity, that is, alpha and gamma diversity are both assessed at the same level of sample coverage, to formulate standardized, coverage‐based beta diversity. This extension of iNEXT to beta diversity required the development of novel concepts and theories, including a formal proof and simulation‐based demonstration that the resulting standardized beta diversity removes the dependence of beta diversity on both gamma and alpha values, and thus reflects the pure among‐assemblage differentiation. The proposed standardization is illustrated with spatial, temporal, and spatiotemporal datasets, while the freeware iNEXT.beta3D facilitates all computations and graphics. [ABSTRACT FROM AUTHOR]

Stereolithography additive manufacturing (SLA-AM) can be used to produce ceramic structures by selectively curing a photosensitive resin that has ceramic powder in it. The photosensitive resin acts as a ceramic powder binder, which is burned, and the remaining ceramic part is sintered during post-processing using a temperature–time-controlled furnace. Due to this process, the ceramic part shrinks and becomes porous. Moreover, additive manufacturing leads to the orthotropic behavior of the manufactured parts. This article studies the effect of the manufacturing orientation of ceramic parts produced via SLA-AM on dimensional accuracy. Scaled CAD models were created by including the calculated shrinkage factor. The dimensions of the final sintered specimens were very close to the desired dimensions. As sintering induces porosity and reduces the mechanical strength, in this study, the effect of orientation on strength was investigated, and it was concluded that the on-edge specimen possessed by far the highest strength in terms of both compression and tension. [ABSTRACT FROM AUTHOR]

Monocultures and mixed plantations have long been applied in forestry and landscape restoration to maximize the benefits of plantations. These different plantations can have unpredictable effects on the forest ecosystem. Monocultures and mixed plantations may influence soil bacterial communities, yet the underlying mechanisms of the soil bacterial community similarity response to monocultures and mixed plantations are still unknown. This study aimed to unravel how the community assembly processes and their associated factors mediate soil bacterial community similarity among monocultures and mixed plantations. We present a conceptual model to understand the mechanisms controlling soil bacterial community similarity among monocultures and mixed plantations. We tested these conceptual model hypotheses and the underlying mechanisms by conducting experiments in three plantation forest regions in southern China. We found that different monocultures led to a highly dissimilar environment, which increased heterogeneous selection and resulted in a high dissimilarity of soil bacterial communities among monocultures. Compared with monocultures, mixed plantations afford more similar environmental conditions for soil bacterial communities and decrease the heterogeneous selection process, leading to a higher soil bacterial similarity among mixed plantations. In addition, we demonstrate that stochastic processes are also the dominant driver in determining the soil bacterial community similarity among mixed plantations. Overall, the conversion from monocultures to mixed plantations affects the community assembly process by altering environmental similarity and edaphic factors, subsequently determining the similarity of soil bacterial communities. Our study can provide scientific guidance for exploring the role of mixed plantations in forest management. [ABSTRACT FROM AUTHOR]

Halide perovskites are qualified to meet the flexibility demands of optoelectronic field because of their merits of flexibility, lightness, and low cost. However, the intrinsic defects and deformation‐induced ductile fracture in both perovskite and buried interface significantly restrict the photoelectric performance and longevity of flexible perovskite solar cells (PVSCs). Here, a dual‐dynamic cross‐linking network is schemed to boost the photovoltaic efficiency and mechanical stability of flexible PVSCs by incorporating natural polymerizable small molecule α‐lipoic acid (LA). The LA therein can be autonomously ring‐opening polymerized through dynamic disulfide bonds and hydrogen bonds, concurrently forming coordination bonds to interact with perovskite component. Importantly, the polymerization product can serve as efficacious passivating and toughening agents to simultaneously optimize interfacial contact, enhance perovskite crystallinity and sustain robust mechanical bendability. Subsequently, the rigid (or flexible) p‐i‐n device realizes a champion efficiency of 22.43% (or 19.03%) with prominent operational stability. Moreover, the dual‐dynamic cross‐linking network endows PVSCs with bendability and self‐healing capacity, allowing the optimized devices to retain >80% efficiency after 3000 bending cycles, and subsequently restore to ≈95% of its initial efficiency under mild heat‐treatment. This toughening and self‐healing strategy provides a facile and efficient path to prolong operational lifetime of flexible device. [ABSTRACT FROM AUTHOR]

We aimed to determine how patterns of functional and taxonomic dissimilarities and their components differ between disturbed and undisturbed plant communities. Taxonomic (species) and functional (trait) diversity are key aspects of biodiversity, and their respective dissimilarities are important in diversity scaling and for informing conservation. We utilized a pseudo-experimental setting, the Basingstoke Canal, UK, where sections of canal bank have been repaired over a four-year period and are interspersed with sections left undisturbed. We collected plant community data, computed functional beta diversity and taxonomic beta diversity and partitioned them into species loss and replacement components. We compared disturbed and undisturbed plots with respect to these dissimilarity measures, the time since disturbance, invasive species, plant life-forms and environmental dissimilarity. We found high levels of taxonomic (85–90%) and functional (70–76%) dissimilarities between disturbed and undisturbed sites, primarily driven by turnover. The total dissimilarity was lower for functional dissimilarity than taxonomic dissimilarity. Disturbed sites had greater between-site taxonomic and functional dissimilarities and lower plant abundances than undisturbed sites, driven by both turnover and nestedness components. The disturbed site functional diversity diverged strongly from null expectations. We found no significant effects of time since disturbance, environmental variables or invasive species, possibly indicating the dominance of stochastic, local-scale processes. However, disturbed sites had lower levels of phanerophyte richness and higher levels of therophyte richness. Our results indicate that small-scale disturbances may increase taxonomic and functional between-community dissimilarities in anthropogenic habitats without increasing invasive species, lending support to local-scale conservation that enhances habitat heterogeneity to promote taxonomic diversity and its corresponding biotic functions. [ABSTRACT FROM AUTHOR]

Plant microbiomes are known to influence host fitness and ecosystem functioning, but mechanisms regulating their structure are poorly understood.Here, we explored the assembly mechanisms of leaf epiphytic and endophytic bacterial communities using a subtropical forest biodiversity experiment.Both epiphytic and endophytic bacterial diversity increased as host tree diversity increased. However, the increased epiphytic diversity in more diverse forests was driven by greater epiphytic diversity (i.e. greater α‐diversity) on individual trees, whereas the increased endophytic diversity in more diverse forests was driven by greater dissimilarity in endophytic composition (i.e. greater β‐diversity) among trees. Mechanistically, responses of epiphytes to changes in host diversity were consistent with mass effects, whereas responses of endophytes were consistent with species sorting.Synthesis. These results provided novel experimental evidence that biodiversity declines of plant species will lead to biodiversity declines of plant‐associated microbiomes, but the underlying mechanism may differ between habitats on the plant host. [ABSTRACT FROM AUTHOR]

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Natural solutions by which humans can overcome challenges have been severely hampered by biodiversity losses. It is essential to understand the key natural variables that influence changes in community diversity to maintain ecosystem function. The Ziwuling area has a natural recovery succession history of 150 years. Therefore, a survey was conducted to compare species composition characteristics across different vegetation recovery stages while also providing a phylogenetic and taxonomic response to the correlation between beta diversity and soil stoichiometry. The results showed that beta diversity and endemic plants had a similar single-peak temporal pattern. Soil organic carbon (SOC) accumulation was significantly positively correlated with total nitrogen (TN) and was also negatively correlated with total phosphorus (TP). Overall, soil TN, time since vegetation restoration (TVR in years), and W-SS (endemic woody plants at each stage) were able to explain 94.3% of the total variation in beta diversity. Temperate species such as Carex lanceolata, Lespedeza bicolor, and Sophora davidii are the basis for community construction. Community beta diversity patterns are the result of a mixture of ecological (e.g., climate patterns and soil nutrients) and evolutionary processes. This study combined plant resource needs with how they respond to natural recovery times in order to provide useful knowledge to protect biodiversity, the nutrient cycle, and the function of restoration ecology. [ABSTRACT FROM AUTHOR]

The main sources of the ambient seismic wavefield in the microseismic frequency band (peaking in the ∼0.04–0.5 Hz range) are earth's oceans, namely the wind‐driven surface gravity waves (SGW) that couple oscillations into the seafloor and the upper crust underneath. Cyclones (e.g., hurricanes, typhoons) and other atmospheric storms are efficient generators of high ocean waves that in turn generate distinct microseismic signatures. In this study, we perform a polarization (i.e., three‐component) beamforming analysis of microseismic (0.05–0.16 Hz) retrograde Rayleigh and Love waves during major Atlantic hurricanes using a virtual array of seismometers in Eastern Canada. Oceanic hindcasts and meteorological data are used for comparison. No continuous generation of microseism along the hurricane track is observed but rather an intermittent signal generation. Both seismic surface wave types show clear cyclone‐related microseismic signatures that are consistent with a colocated generation at near‐coastal or shallow regions, however the Love wavefield is comparatively less coherent. We identify two different kinds of intermittent signals: (a) azimuthally progressive signals that originate with a nearly constant spatial lag pointing toward the trail of the hurricanes and (b) azimuthally steady signals remaining nearly constant in direction of arrival even days after the hurricane significantly changed its azimuth. This high complexity highlights the need for further studies to unravel the interplay between site‐dependent geophysical parameters, SGW forcing at depth and microseismic wavefield radiation and propagation, as well as the potential use of cyclone microseisms as passive natural sources. Plain Language Summary: Ocean waves are responsible for the generation of microseisms, faint ground vibrations with complex characteristics and which comprise a major portion of the background seismic noise of the earth. In this study, we implement an onshore seismic detection method to study microseisms generated by cyclones in the North Atlantic ocean (hurricanes), as these are known to be major generators of large ocean waves. We observed that cyclones only seem to generate detectable microseisms as they move over certain regions in the ocean, namely near coastal or shallow water regions. The direction of arrival of these microseisms is sometimes constant, at other times it shifts azimuth along with the hurricanes. Understanding the relationship between ocean waves and cyclone‐related microseisms is an important step for the potential use of these vibrations to study the earth, ocean and atmosphere. Key Points: Primary and secondary microseismic Love and Rayleigh waves excited by Atlantic cyclones were detected via onshore polarization beamformingWe observed microseisms related to cyclones as they pass over the northwestern Atlantic margin off NewfoundlandSome microseisms have constant direction of arrival, others are azimuthally progressive and reflect the advance of the cyclone [ABSTRACT FROM AUTHOR]

Ecological communities are assembled through a series of multiple processes, including dispersal, abiotic and biotic filtering, and ecological drift. Although these assembly processes act in concert to structure local communities, their relative importance is considerably variable among study systems. While such contingency of community assembly has been widely appreciated, the empirical and theoretical evidence is scattered around in the literature, and few efforts have been made to synthesize it. In this mini‐review, we summarize the accumulated evidence of the context‐dependency of community assembly rules, to reach a rough generalization of the contingency. Specifically, we argue that spatial and temporal dimensions can serve as general axes that regulate the relative importance of assembly processes. To this end, we synthesize the current understanding of how the relative importance of multiple assembly processes changes with spatial scales and complexity, and with time in the long and short terms. This review concludes that spatial and temporal dimensions can be common currencies of community assembly rules that are shared across various systems. [ABSTRACT FROM AUTHOR]

Hummingbirds have evolved to hover and manoeuvre with exceptional flight control. This is enabled by their musculoskeletal system that successfully exploits the agile motion of flapping wings. Here, we synthesize existing empirical and modelling data to generate novel hypotheses for principles of hummingbird wing actuation. These may help guide future experimental work and provide insights into the evolution and robotic emulation of hummingbird flight. We develop a functional model of the hummingbird musculoskeletal system, which predicts instantaneous, three-dimensional torque produced by primary (pectoralis and supracoracoideus) and combined secondary muscles. The model also predicts primary muscle contractile behaviour, including stress, strain, elasticity and work. Results suggest that the primary muscles (i.e. the flight 'engine') function as diverse effectors, as they do not simply power the stroke, but also actively deviate and pitch the wing with comparable actuation torque. The results also suggest that the secondary muscles produce controlled-tightening effects by acting against primary muscles in deviation and pitching. The diverse effects of the pectoralis are associated with the evolution of a comparatively enormous bicipital crest on the humerus. [ABSTRACT FROM AUTHOR]

Improvements in the high accuracy of micro‐phasor measurement unit (μPMU) and synchrophasor unit provide the distribution network a special perspective to access full observability in the presence of renewable distribution generations (DGs). In this regard, modelling the uncertainty effects for accurate fault detection in smart grids has become a novel turning point. This research work attempts to develop a novel stochastic architecture based on unscented transform (UT), which requires a very few number of μPMUs, to communicate in a secured blockchain‐enabled structure to allocate and detect the smart grid irregularities and faults. Such a blockchain‐based technique can be beneficial for encrypting the data transmitted among the μPMUs in the smart grid consisting of a variety of distributed energy sources (DERs) and high impedance fault events, while incorporating the uncertainties associated with the load and individual installation sensors. The proposed stochastic structure benefits from voltage measurement and uses its angle in event placement that performs more efficiently than the conventional sensors based on high‐voltage and current metering. The simulation results show the great precision and effectiveness of the proposed model during various fault scenarios in smart grid. [ABSTRACT FROM AUTHOR]

To improve the comprehensive performance of the distributed wheel-side four-wheel-drive electric bus, the problem of optimal distribution of the driving torque of the four wheel-side motors is studied. Aiming at the poor economy and failure of switching control due to the consideration of both straight and steering conditions, this paper proposes a fuzzy yaw moment control strategy based on the golden section search algorithm. Under full working conditions, according to the efficiency characteristics of the front and rear axle drive motors, the golden section search algorithm is used to determine the best front and rear axle motor torque distribution coefficient K to distribute the front and rear axle motor torques. Given the stability problems existing in the steering conditions, based on the optimal torque distribution of the front and rear axles, fuzzy control is used to calculate the expected yaw moment, and the left and right wheel torques are adjusted in real time. The simulation is carried out through TruckSim and MATLAB/Simulink, and a hardware-in-the-loop platform is built for experimentation under step steering conditions and sine wave steering conditions. The results show that the proposed torque optimal distribution strategy can optimally distribute the torque of the four drive motors through the real-time identification of working conditions. Compared with the four-wheel equal distribution, under two different steering conditions, the torque distribution efficiency of the torque distribution strategy using the golden section search algorithm increased by 4.35% and 3.83%, respectively. The energy utilization rate of the whole vehicle is improved under all of the working conditions. Under steering conditions, compared with the four-wheel equal distribution and the torque distribution strategy using the golden section search algorithm under all of the conditions, the yaw rate deviation and the slip angle deviation can be reduced, and the yaw stability has been improved. [ABSTRACT FROM AUTHOR]

This paper proposes a reconstruction algorithm for the geometric shapes of static overhead transmission lines that is based on the spatial coordinate data (obtained by field mapping) and the corresponding inclination data (obtained by attitude sensors). The algorithm takes the piecewise cubic Hermite interpolation function as the basic framework and corrects the aforementioned two types of data based on the “minimum energy principle” of the transmission line system. The introduction of a new energy function in modified energy method (MEM) overcame the shortcomings of conventional energy method (CEM) in fairing strategy, and the new Fairing Criterion made result curves more consistent with the mechanical properties of transmission lines. In the numerical simulation tests, the two energy methods were compared in terms of load type, horizontal span, elevation difference, and anti-disturbance ability, which showed that MEM has a higher reconstruction accuracy (average Euclidean distance is less than 1 cm) and better robustness than CEM. Meanwhile, the key parameters involved in the algorithm were discussed to guide the application in practical engineering. In addition, measurement tests under non-uniform icing were carried out in the field test station, and the results showed that the maximum relative error is less than 0.1%. [ABSTRACT FROM AUTHOR]

Aquatic insects in the order Trichoptera are extremely diverse in number of species and their trophic roles. However, their distribution and diversity patterns are poorly known in the Neotropics, including the species restricted to tropical mountain ecosystems. Recent studies in tropical mountains have shown high levels of endemism of aquatic insects and changes in the composition of communities over short distances. Still, the incidence of environmental filters that explain such patterns has not been addressed quantitatively. Given the relevance of understanding Trichoptera spatial diversity patterns to prioritize conservation areas for freshwaters, as well as to obtain baseline information to predict changes in aquatic communities facing global environmental changes, we assessed the species distribution and assemblages of caddisflies along an elevational gradient from 600 to 3,600 m a.s.l. on the equatorial Andes. In this area, we had long-term continuous climate data with hourly resolution. We collected adult caddisflies in seven localities along this gradient using light traps. We sampled each locality for two hours after sunset for three consecutive days. All specimens collected were identified to species or morphospecies. Our results showed an increase in species and genera numbers with decreasing altitude, albeit no significant. Minimum air temperature is the main environmental variable explaining Trichoptera community assemblages. β‐diversity (taxon turnover among sites), as opposed to species richness, increased with altitude and showed a bimodal distribution along the elevation gradient for both genera and species assemblages, which resulted in a significant shift in community composition of species and genera at 2,000 m a.s.l. Our null-models confirm the observed patterns of B-diversity are non-random and suggest a strong environmental filtering of tropical caddisflies community assemblies and turnover. Geographic distance coupled with changes in environmental conditions along the elevation gradient explained a high percentage of community variance, as documented for other taxa (e.g., vascular plants), suggesting the importance of securing habitat connectivity along the altitudinal gradient to protect aquatic insect diversity effectively. [ABSTRACT FROM AUTHOR]

Electrokinetics of deformable interfaces holds the key in developing bio-mimetic micro-devices for probing microvascular physiology and performing in vitro bio-analytical procedures. While such systems have been analyzed in the literature with the aid of a set of simplifying assumptions to some extent, implications of axial modulations in the surface potential and interfacial slip, otherwise ominous artifacts of the coupling between intrinsic electro-chemistry and substrate wettability in practical realms of surface engineering, remain grossly unaddressed in the same context. Here, we bring out the interplay of the wall compliance, periodically modulated surface potential, and patterned interfacial slip that is itself coupled with the interfacial electrochemistry, toward altering the internal hydrodynamics of a deformable microfluidic channel. Manifested in terms of a perturbed pressure field, this essentially leads to an alteration in the load bearing capacity of the concerned electro-mechanical system. By exploiting this unique coupling of the interfacial electro-mechanics, hydrodynamics, and substrate elasticity, we further demonstrate the plausibility of a significant augmentation in the load bearing capacity of the resulting system, over favorable parametric regimes. This opens up emerging possibilities of developing novel electro-kinetically modulated lubricated systems with giant augmentations in their load bearing performance. [ABSTRACT FROM AUTHOR]

β‐Diversity, commonly defined as the compositional variation among localities that links local diversity (α‐diversity) and regional diversity (γ‐diversity), can arise from two different ecological phenomena, namely the spatial species turnover (i.e., species replacement) and the nestedness of assemblages (i.e., species loss). However, any assessment that does not account for stochasticity in community assembly could be biased and misinform conservation management. In this study, we aimed to provide a better understanding of the overall ecological phenomena underlying stream β‐diversity along elevation gradients and to contribute to the rich debate on null model approaches to identify nonrandom patterns in the distribution of taxa. Based on presence‐absence data of 78 stream invertebrate families from 309 sites located in the Swiss Alpine region, we analyzed the effect size of nonrandom spatial distribution of stream invertebrates on the β‐diversity and its two components (i.e., turnover and nestedness). We used a modeling framework that allows exploring the complete range of existing algorithms used in null model analysis and assessing how distribution patterns vary according to an array of possible ecological assumptions. Overall, the turnover of stream invertebrates and the nestedness of assemblages were significantly lower and higher, respectively, than the ones expected by chance. This pattern increased with elevation, and the consistent trend observed along the altitudinal gradient, even in the most conservative analysis, strengthened our findings. Our study suggests that deterministic distribution of stream invertebrates in the Swiss Alpine region is significantly driven by differential dispersal capacity and environmental stress gradients. As long as the ecological assumptions for constructing the null models and their implications are acknowledged, we believe that they still represent useful tools to measure the effect size of nonrandom spatial distribution of taxa on β‐diversity. [ABSTRACT FROM AUTHOR]

Beta(β)‐diversity, or site‐to‐site variation in species composition, generally decreases with increasing latitude, and the underlying processes driving this pattern have been challenging to elucidate because the signals of community assembly processes are scale‐dependent. In this meta‐analysis, by synthesising the results of 103 studies that were distributed globally and conducted at various spatial scales, we revealed a latitudinal gradient in the detectable assembly processes of vascular plant communities. Variations in plant community composition at low and high latitudes were mainly explained by geographic variables, suggesting that distance decay and dispersal limitations causing spatial aggregation are influential in these regions. In contrast, variation in species composition correlated most strongly with environmental variables at mid‐latitudes (20–30°), reflecting the importance of environmental filtering, although this unimodal pattern was not statistically significant. Importantly, our analysis revealed the effects of different spatial scales, such that the correlation with spatial variables was stronger at smaller sampling extents, and environmental variables were more influential at larger sampling extents. We concluded that plant communities are driven by different community assembly processes in distinct biogeographical regions, suggesting that the latitudinal gradient of biodiversity is created by a combination of multiple processes that vary with environmental and species size differences. [ABSTRACT FROM AUTHOR]

Climate, topography, and human activities are known to influence plant diversity. In the present study, species-abundance distribution (SAD) patterns of the shrub community were fitted, and the mechanism of contribution of 22 driving factors was assessed. The results showed that the α-diversity index exhibited no significant differences between artificial disturbance and the natural community. The Zipf and Zipf–Mandelbrot models were found to exhibit a good SAD fitting of the communities, thereby exhibiting a different diversity structure. It was observed that the SAD followed more than one rule, and the Zipf–Mandelbrot model was better than other models. The gradient boosting model indicated that precipitation in the wettest month, annual precipitation, and slope direction showed the strongest impact on plant richness. The indicator species of the artificial disturbance and natural community were identified from a multiple regression tree. Furthermore, an increase in species diversity was observed with a rise in latitude, exhibiting a single-peaked curve with increased altitude. β-diversity analysis indicated that both habitat filtering and the neutral effect influenced the establishment of the natural community, while the establishment of the artificial disturbance community was only affected by habitat filtering. Our study provides a better understanding of the ecological process of the maintenance of shrub-community diversity. [ABSTRACT FROM AUTHOR]

Aim: Understanding the biodiversity–stability relationship has become a central issue in ecology and conservation biology. Although the stabilizing effects of tree species diversity on ecosystem productivity are well recorded in small local communities, they remain poorly understood across scales (from local to larger spatial scales). This study evaluates biodiversity–stability effects from local to larger spatial scales in a large temperate forest region, considering a range of environmental conditions and environmental heterogeneity. Location: North‐eastern China (c. 700,000 km2). Time period: 2005–2017. Major taxa studied: Woody plants. Methods: We define stability as the temporal invariability of biomass productivity. Regional metacommunities representing larger spatial scales were developed by aggregating multiple sets of local field plots. Simple regression analysis was used to test biodiversity–stability relationships in metacommunities. Piecewise structural equation modelling was then used to disentangle the effects of diversity and abiotic variables on forest stability at local and larger spatial scales. Multiple mixed‐effects regression models were used to determine the relative contribution of individual predictive variables to stability across spatial scales. Results: We found that local diversity (alpha diversity) was positively related to the stability of local communities (alpha stability), whereas species turnover across space (beta diversity) was positively related to asynchronous dynamics among local communities (spatial asynchrony), regardless of whether abiotic factors were considered or not. We also found that environmental conditions and environmental heterogeneity affected forest stability across scales. The effect of spatial asynchrony on gamma stability was greater than that of alpha stability. Main conclusions: Our results imply that spatial asynchrony is a key to maintaining the stability of ecosystem productivity within a large temperate forest region. We suggest that diverse forests and heterogeneous landscapes should be sustained at multiple spatial scales to buffer the negative effects of climate change and forest degradation. [ABSTRACT FROM AUTHOR]

Interfacial lattice mismatch and adverse reaction are the key issues hindering the development of nickel oxide (NiOx)‐based inverted perovskite solar cells (PVSCs). Herein, a p‐chlorobenzenesulfonic acid (CBSA) self‐assembled small‐molecule (SASM) is adopted to anchor NiOx and perovskite crystals to endow dual‐passivation. The chlorine terminal of SASMs can provide growth sites for perovskite, leading to interfacial strain release. Meanwhile, the sulfonic acid group from SASMs can passivate surface defects of NiOx, conducive to charge carrier extraction. In addition, the self‐assembled layer inhibits the adverse interfacial reaction by preventing NiOx contact with perovskite. Therefore, the NiOx/CBSA‐based PVSCs obtain a champion power conversion efficiency (PCE) of 21.8%. Of particular note, the unencapsulated devices can retain above 80% of their initial PCE values after storage in a nitrogen atmosphere for 3000 h, in air with a relative humidity of 50–70% for 1000 h, and heating at 85 °C for 800 h, respectively. [ABSTRACT FROM AUTHOR]

In the absence of environmental heterogeneity, spatial variation among local communities can be mostly attributed to random dispersal, demographic stochasticity and species interactions causing historical contingency in colonization (e.g. priority effects). The consequences of demographic stochasticity and random dispersal are highly dependent on community size, regional richness and local richness, which, along with historical contingency can be strongly affected by spatial isolation and the presence of predators. Here, we tested whether and how the presence of a generalist predatory fish and spatial isolation can change spatial community variability in artificial ponds by manipulating the presence/absence of fish (redbreast tilapia) at three different distances from a source wetland. We then used null models to compute how much the observed community variability within treatments deviates from the expected from randomly reassembled communities (i.e. beta‐deviation). We found that spatial isolation can have both negative and positive effects on community variability, and their importance may depend on the presence of predatory fish. Negative effects likely occurred because predatory insects cannot always successfully colonize highly isolated ponds, causing the abundance of herbivores and detritivores to increase, consequently increasing community size, which is known to decrease the importance of demographic stochasticity. However, when fish are absent, the more isolated communities exhibit more community variability than is expected from random community assembly. We believe that such an increase in variability is most likely due to an increase in the importance of historical contingency in colonization, generating more distinct communities in isolated ponds. Such effects were absent in the presence of generalist predatory fish, likely because fish prevented any early colonizing taxa from becoming too abundant. Our findings show that the presence of generalist predators can change how community variability responds to spatial isolation. [ABSTRACT FROM AUTHOR]

Background: Separation of biotic and abiotic impacts on species diversity distribution patterns across a significant climatic gradient is a challenge in the study of diversity maintenance mechanisms. The basic task is to reconcile scale-dependent effects of abiotic and biotic processes on species distribution models. Here, we used a hierarchical modeling method to detect the host specificities of bark beetles (Scolytinae and Platypodinae) with their dependent tree communities across a steep climatic gradient, which was embedded within a relatively homogenous spatial niche. Results: Species turnover of both trees and bark beetles have an opposite pattern along the climatic proxy (represented by the elevation gradients) at the regional scale, but not at local spatial scales. This pattern confirmed the hypothesis wherein emphasis was on influences of macro-climate on local biotic interactions between trees and hosted bark beetle communities, whereas local biotic relations, represented by host specificity dependence, were regionally conserved. Conclusions: At a confined spatial scale, cross-taxa comparisons of β-diversity highlighted the importance of simultaneous impacts from both extrinsic factors related to geography and environment, and intrinsic factors related to organism characteristics. The effects of tree abundance and phylogeny diversity on bark beetle diversity were, to a large extent, indirect, operating via changes in bark beetle abundance through spatial and temporal dynamics of resources distribution. Tree host dependence, which was considered and represented by host specificities, plays a minor role on the hosted beetle community in this concealed wood decomposing interacting system. [ABSTRACT FROM AUTHOR]

A substantial body of research has addressed the equilibrium cross‐sectional geometry of straight noncohesive channels, along with bends having fixed outer banks. However, development of a characteristic cross‐section during active migration has been confounded by inaccurate treatment of noncohesive bank erosion processes. This analysis characterizes a steady‐state migrating cross‐section and the associated migration rate for the highly conceptualized case of an infinite bend of constant centerline radius with noncohesive lower banks consisting of uniform‐sized grains mobilized as bedload. Analytical, numerical, and field analyses are presented to rationally constrain the geometry and obtain a physically based migration rate equation dependent on the following dimensionless groupings: excess Shields stress, flow depth to radius of curvature ratio, and noncohesive bank thickness to grain size ratio. Migration rate is shown to be dictated by transverse sediment flux at the thalweg due to secondary flow, not bank slope as in previous formulations developed from similar principles. Simple outward translation of the noncohesive portion of the cross section is achieved with concurrent mass failure in the upper cohesive layer. Such translation cannot be achieved using a linear excess shear formulation applied to noncohesive fluvial erosion. A numerical model of cross‐sectional evolution to steady‐state migration is developed; when applied to the lower Mackinaw River in Illinois, it reveals that the river behaves as if the critical shear stress is considerably larger than that indicated by the grain size distribution. This conceptualized treatment is intended to provide a canonical basis of comparison for actual meander bend geometries. Plain Language Summary: Meandering rivers erode their outer banks and deposit coarse‐grained sand and gravel on the inside of bends. Finer‐grained sediments (fine sand, silt, and clay) deposit on top of the coarse‐grained bar deposits. As the river migrates back and forth across its floodplain, the outer bank is commonly eroding into a bar deposit left behind by a former river configuration. This type of bank with a lower layer of sand and gravel and an upper layer of cohesive soil is known as a composite riverbank. River engineers need to predict migration rates, and the equation used to model erosion of cohesive soils is mathematically simple. Largely because of its simplicity, it has been used extensively to model coarse‐grained sand/gravel erosion, even though the dominant physical factors governing the erosion are quite different than for cohesive soils. In this study, the characteristic shape and migration rate of a river with noncohesive banks is sought, using physical principles of sand/gravel erosion and deposition rather than the simplistic forms used for cohesive soils. A migration rate formulation is developed, and key aspects of the river cross‐sectional shape are determined for an idealized case of a river bend migrating at steady state. Key Points: Migration rate in the idealized case is dictated by transverse sediment flux at the thalweg due to secondary flow, not bank slopeThe derived migration rate uses dimensionless groupings: excess Shields stress, depth/radius, and grain size/noncohesive layer thicknessThe linear excess shear stress formulation valid for cohesive soils mischaracterizes fluvial erosion when applied to noncohesive banks [ABSTRACT FROM AUTHOR]

The contribution of seasonality in species communities to elevational diversity of tropical insects remains poorly understood. We here assessed seasonal patterns and drivers of bee diversity in the Eastern Afromontane Biodiversity Hotspot, Kenya, to understand the contribution of seasonality to elevational biodiversity patterns. Bee species and plant species visited by bees were recorded on 50 study plots in regrowth vegetation across four major seasons along two elevation gradients from 525 to 2530 m above sea level. Bees were sampled by transect walks using sweep nets and aspirators. We examined how local species richness (α‐diversity) and seasonal changes in local species communities (β‐diversity) contribute to species richness across seasons (γ‐diversity) along elevation gradients. Using a multimodel inference framework, we identified the contribution of climate and floral seasonality to elevational patterns in bee diversity. We found that both α‐ and γ‐diversity decreased with elevation. Seasonal β‐diversity decreased with elevation and the high turnover of species across seasons contributed to a considerably higher γ‐ than α‐diversity on study plots. A combination of seasonality in climate and the seasonal turnover of floral resources best explained the seasonality in bee species communities (seasonal β‐diversity). We, therefore, conclude that, despite the more stable, and favorable climatic conditions in the tropics (in comparison to temperate regions), climatic seasonality and its influence on bees' floral resources largely determined seasonal patterns of bee species diversity along elevation gradients on tropical mountains. [ABSTRACT FROM AUTHOR]