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Early heat and drought priming may increase the plant's ability to resist later drought and heat stress. However, it remains unclear whether combined heat and drought priming can enhance the acclimation of plants to later combined stress by improving physiological activities. In this study, maize seedlings were first pre-exposed twice to heat, drought, and a combination of stresses followed by recovery, and then subjected to six days of more severe stresses. A considerable reduction in photosynthetic pigment content, stomatal size, and photosynthesis was observed under heat and drought conditions, and the changes in the above indicators were amplified under combined stress conditions. Stress priming improves antioxidant defense and cellular osmoregulation, as indicated by improved superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione reductase (GR), and ascorbate peroxidase activities, as well as elevated soluble sugar (SS) and proline (Pro) contents. Lower superoxide anion and malondialdehyde contents and injury index in the primed seedlings demonstrated the mitigation of oxidative stress. ROC analysis revealed that SOD and POD had considerable reliability in determining that maize seedlings were experiencing heat stress (AUC = 0.941–0.971); GR and SS were capable of accurately monitoring drought stress that was being experienced by plants (AUC = 0.919–0.958); and SOD, GR, and Pro had more capability for detecting the combination of heat and drought stress (AUC = 0.907–0.958). Collectively, the primed seedlings exhibited better performance than the non-primed seedlings, exhibiting stronger stress acclimation supported by an effective antioxidant defense system and osmoregulatory function. [ABSTRACT FROM AUTHOR]

Soil degradation has exacerbated the gap between crop yield and increasing food demands, and unreasonable field management is one of the main reasons for soil degradation. As a classic orchard soil management mode, living grass mulch can effectively change the hydrothermal environment and soil physicochemical properties of the 'soil–vegetation–atmosphere' microclimate of apple orchards. However, these improvement effects are mainly affected by climatic conditions, mulch methods, vegetation varieties and continuous grass-growing years. To evaluate the different effects of living grass mulch and the main influencing factors on soil physicochemical properties of apple orchards in China, in this study, we conducted a meta-analysis using data from 53 peer-reviewed publications to carry out soil quality assessment. The results showed that compared with clear tillage, continuous living grass mulch in apple orchards could improve soil function and performance by about 56% and increase soil enzyme activities by 10–120%, on average, whereas the soil organic matter under the effect of artificial grass and natural grass significantly increased by 29.6% and 14.6%, respectively. Artificial grass in temperate and warm, temperate, semi-humid climate regions had a greater overall improvement effect on the soil physicochemical environment than natural grass. Clover was found to be the most suitable for planting in apple orchards in temperate, semi-humid climate regions, whereas both clover and ryegrass were the best choices in warm, temperate, semi-humid climate regions. The interaction effects of different soil physicochemical properties in apple orchards in warm, temperate, semi-humid climate regions were greater than those in warm, temperate, arid climates and temperate, semi-humid climate regions. The response sensitivity of soil organic matter, organic carbon, urease, catalase, sucrose and cellulase to the living grass mulch effect of apple orchards was greater than that of other soil properties. [ABSTRACT FROM AUTHOR]

Herein, we prepared the g-C3N4/Gd-doped Bi2WO6 Z-scheme heterojunction (BCN) composites by a simple hydrothermal method. The composites were investigated by SEM (EDX), TEM, XRD, XPS, UV–Vis DRS and PL analysis. The photocatalytic performance of composites was envaulted by degrading methylene blue (MB) under the irradiation of a 300 W mercury lamp. The results demonstrated that coupling g-C3N4 and doping Gd 3+ effectively enhanced the photocatalytic efficiency of pure Bi2WO6. The 92% of MB was degraded within 120 min by optimal 0.15–100 BCN sample, being 1.61 times as that of Bi2WO6. The greatly enhanced performance of 0.15–100 BCN was due to the synergistic effect of Gd 3+ doping and g-C3N4 coupling, which maintained high redox capacity. According to the experiment of capture active species, Z-scheme charge transfer mechanism was also deduced. This study may provide an efficient and green method for the treatment of dyestuff industrial wastewater. [ABSTRACT FROM AUTHOR]

The rapid and accurate acquisition of nitrogen, phosphorus and potassium nutrient contents in grape leaves is critical for improving grape yields and quality and for industrial development. In this study, crop growth was non-destructively monitored based on unmanned aerial vehicle (UAV) remote sensing technology. Three irrigation levels (W1, W2 and W3) and four fertilization levels (F3, F2, F1 and F0) were set in this study, and drip irrigation fertilization treatments adopted a complete block design. A correlation analysis was conducted using UAV multispectral image data obtained from 2019 to 2021 and the field-measured leaf nitrogen content (LNC), leaf potassium content (LKC) and leaf phosphorus content (LPC) values; from the results, the vegetation indices (VIs) that were sensitive to LNC, LKC and LPC were determined. By combining spectral indices with partial least squares (PLS), random forest (RF), support vector machine (SVM) and extreme learning machine (ELM) machine-learning algorithms, prediction models were established. Finally, the optimal combinations of spectral variables and machine learning models for predicting LNC, LPC and LKC in each grape growth period were determined. The results showed that: (1) there were high demands for nitrogen during the new shoot growth and flowering periods, potassium was the main nutrient absorbed in the fruit expansion period, and phosphorus was the main nutrient absorbed in the veraison and maturity periods; (2) combining multiple spectral variables with the RF, SVM and ELM models could result in improved LNC, LPC and LKC predictions. The optimal prediction model determination coefficient (R2) derived during the new shoot growth period was above 0.65, and that obtained during the other growth periods was above 0.75. The relative root mean square error (RRMSE) of the above models was below 0.20, and the Willmott consistency index (WIA) was above 0.88. In conclusion, UAV multispectral images have good application effects when predicting nutrient contents in grape leaves. This study can provide technical support for accurate vineyard nutrient management using UAV platforms. [ABSTRACT FROM AUTHOR]

More frequent and more intense heat waves and greater drought stress will occur in the future climate environment. Short-term extreme heat and drought stress often occur simultaneously after winter wheat anthesis, which has become the major constraint threatening future wheat yield. In this study, short-term heat, drought and their combination stress were applied to wheat plants after anthesis, and all wheat plants were restored to the outdoor normal temperature and full watering after stress treatment. The aim of the current study was to evaluate the role of nitrogen (N) in modulating the effects of post-anthesis short-term heat, drought and their combination stress on photosynthesis, N metabolism-related enzymes, the accumulation of N and protein and growth, as well as on the yield and water (WUE) and N use efficiency (NUE) of wheat after stress treatment. The results showed that compared with low N application (N1), medium application (N2) enhanced the activities of nitrate reductase (NR) and glutamine synthase (GS) in grains under post-anthesis heat and drought stress alone, which provided a basis for the accumulation of N and protein in grains at the later stage of growth. Under post-anthesis individual stresses, N2 or high application (N3) increased the leaf photosynthetic rate (An), PSII photochemical efficiency and instantaneous WUE compared with N1, whereas these parameters were usually significantly improved by N1 application under post-anthesis combined stress. The positive effect of increased An by N application on growth was well represented in a higher green leaf area, aboveground dry mass and plant height, and the variation in An can be explained more accurately by the N content per unit leaf area. Short-term heat, drought and combined stress after anthesis resulted in a pronounced decrease in yield by reducing grain number per spike and thousand kernel weight. The reduction in NUE under combined stress was higher than that under individual heat and drought stress. Compared with N1, N2 or N3 application significantly prevented the decrease in yield and NUE caused by post-anthesis heat and drought stress alone. However, N1 application was conducive to improving the productivity, WUE and NUE of wheat when exposed to post-anthesis combined stress. The current data indicated that under short-term individual heat and drought stress after anthesis, appropriately increasing N application effectively improved the growth and physiological activity of wheat compared with N1, alleviating the reduction in yield, WUE and NUE. However, under combined stress conditions, reducing N application (N1) may be a suitable strategy to compensate for the decrease in yield, WUE and NUE. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) nanosheets are functionalized with 2-methylimidazole (2-MI) to construct a high-efficiency corrosion resistant composite for waterborne polyacrylate coatings. The functional composites are confirmed structural and morphological investigation of sheets by Fourier transform infrared spectroscopy(FT-IR), Raman, x-ray diffraction(XRD), thermogravimetry(TGA), x-ray photoelectron spectroscopy(XPS), scanning electron microscope(SEM) and transmission electron microscopy (TEM) analysis. It is found from the electrochemical test results that after inclusion of 0.5 wt.% 2-MI/rGO nanoparticles incorporation into polyacrylate coatings, the Rct increased from 4.08E03 Ω.cm2 (for pure resin) to 4.02E05 Ω.cm2 in 3.5 wt.% NaCl solution, and the protective efficiency is up to 98.15% for carbon steel. The effective healing process can be concluded that the shield effect of rGO composites greatly extend the diffusion path of corrosion factor and blocked the electrolyte penetration and corrosion extension. [ABSTRACT FROM AUTHOR]

A novel organic–inorganic nanocomposite material of rare earth ions/ poly(styrene‐alt‐maleic anhydride) ionic salt/ reduced graphene oxide (Re3+/SMA‐Is/rGO) was prepared successfully. Poly(styrene‐alt‐maleic anhydride) ionic salt functionalized reduced graphene oxide (SMA‐Is/rGO) was processed with two methods of π–π conjugation and ionization; rare earth ions (Re3+ = La3+, Ce3+ Pr3+) was doped on the surface of rGO by physical mixing. SMA‐Is reduced surface energy and enlarged the interlayer spacing between rGO nanosheets, ensuring that Re3+/SMA‐Is/rGO could form a uniform dispersed phase in the organic coating. The anti‐corrosion performance of the nanocomposite coating was measured by electrochemical techniques in corrosive medium, revealing that introducing the nanocomposite to epoxy matrix exhibited a significant decline of the increase of corrosion potential and corrosion current density. In all samples, La3+/SMA‐Is/rGO had the highest anti‐corrosion performance, and the protection efficiency on mild steel was up to 98.97%. [ABSTRACT FROM AUTHOR]

Single cell RNA sequencing (scRNAseq) can be used to infer a temporal ordering of cellular states. Current methods for the inference of cellular trajectories rely on unbiased dimensionality reduction techniques. However, such biologically agnostic ordering can prove difficult for modeling complex developmental or differentiation processes. The cellular heterogeneity of dynamic biological compartments can result in sparse sampling of key intermediate cell states. To overcome these limitations, we develop a supervised machine learning framework, called Pseudocell Tracer, which infers trajectories in pseudospace rather than in pseudotime. The method uses a supervised encoder, trained with adjacent biological information, to project scRNAseq data into a low-dimensional manifold that maps the transcriptional states a cell can occupy. Then a generative adversarial network (GAN) is used to simulate pesudocells at regular intervals along a virtual cell-state axis. We demonstrate the utility of Pseudocell Tracer by modeling B cells undergoing immunoglobulin class switch recombination (CSR) during a prototypic antigen-induced antibody response. Our results revealed an ordering of key transcription factors regulating CSR to the IgG1 isotype, including the concomitant expression of Nfkb1 and Stat6 prior to the upregulation of Bach2 expression. Furthermore, the expression dynamics of genes encoding cytokine receptors suggest a poised IL-4 signaling state that precedes CSR to the IgG1 isotype. Author summary: In the past decade advances in computing and single cell sequencing technologies have ushered in a new era of discovery in biology and medicine. However, the analysis of single cell data remains challenging, especially when analyzing heterogeneous cellular compartments with complex dynamics. This scenario is especially pronounced in dynamic immune responses of innate and adaptive immune cells. Existing computational tools typically analyze scRNAseq datasets without reference to any of the underlying biology of the system that generates the data. We reason that use of prior knowledge of the system can aid in the extraction of obscured information from scRNAseq datasets. We introduce a framework, Pseudocell Tracer, which takes advantage of validated biological knowledge to guide the inference of cellular trajectories. We apply and validate Pseudocell Tracer by scRNAseq analysis of antigen-specific B cells undergoing immunoglobulin class switch recombination during an antigen-induced humoral immune response. This framework is potentially applicable to single cell data from many other fields with complex dynamics. [ABSTRACT FROM AUTHOR]

A comb copolymer (CC) is designed and prepared in present article, by grafting epoxy resin (E‐20) on poly(styrene‐co‐acrylate). The CC is used as a special dispersant, which leads to a stabilizable reduced graphene oxide (rGO) suspension in organic coatings. The dispersing mechanism is deduced as π‐π attraction between CC and rGO, which is supported by the analysis data of Fourier transform infrared (FTIR) spectra, Raman spectroscopy, scanning electron microscope, transmission electron microscope, and X‐ray photoelectron spectroscopy. The corrosion resistance of CG suspension is determined by electrochemical impedance spectroscopy, the results implies that the anti‐corrosion behavior performed obviously, and protective efficiency is up to 99.53% in Tafel analysis. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48898. [ABSTRACT FROM AUTHOR]

The carbon cycle and underlying environmental drivers are not yet fully understood, and whether climate warming is inducing soil carbon loss remains controversial, largely due to limited evidence from large‐scale observations. With relatively less human disturbance, Yunnan Province, a typical mountainous plateau region in Southwest China, is a favorable place to evaluate environmental effects on soil organic carbon (SOC) dynamics. In this study, soil sampling of the upper 20‐cm soil layer was conducted at sites across Yunnan Province in 1986 and 2010 to estimate topsoil SOC density (SOCD). The changes in SOCD and environmental factors, including initial SOCD value, temperature, precipitation, longitude, latitude, elevation, and slope gradient, were analyzed. The results indicated that the topsoil of Yunnan Province mainly acted as a carbon source during the study period. The topsoil SOCD in 1986 averaged 5.82 kg C m−2 and was higher than that of 2010 (5.45 kg C m−2), corresponding to a 0.14 Pg loss in SOC stock over the 25 years. The northwestern subregion experienced the most drastic SOCD changes, and the SOCD decreased most notably in areas with higher initial SOCD values. Compared with cropland and grassland, more significant SOCD reductions were observed in forest. Among the studied environmental factors, initial SOCD was the main factor associated with SOCD variations. The next most important factor was temperature, followed by precipitation. With high elevation and initial SOCD, the northwestern subregion of Yunnan Province had the most sensitive SOCD changes, underscoring the need for further protection and appropriate management. [ABSTRACT FROM AUTHOR]

In view of the disadvantages of the fluidized quick-freezing device, such as the poor fluidization state and freezing effect of food caused by the uneven distribution of velocity and pressure in the freezing process, sixteen kinds of air distribution plate were designed based on the pore shape ( square, triangle and circle), porosity and pore distribution of the plate to improve the equipment adaptability to different kinds of food and the energy efficiency ratio of the device so as to achieve the purpose of energy saving. The designed air distribution plate can improve the fluidization effect and freezing effect of the fluidized quick-freezing device in freezing process. Meanwhile, the design of different pore shapes can also meet the diverse requirements of food particle shapes. [ABSTRACT FROM AUTHOR]

Background and Aims Depending on the species, water stress affects different growth and developmental processes, mainly due to changes in hydraulic properties and hormonal signalling. This study compared the impact of water stress on tree development and organ growth in three apple cultivars. Methods Trees were differentially irrigated to induce water stress or to provide well-watered conditions in their second and third years of growth. Effects of water stress were evaluated at tree scale by shoot number and proportions of the different types of shoots, and at shoot scale by metamer appearance rate, growth duration and arrest time, as well as organ size. Key Results Water stress promoted early growth cessation, prolonged summer arrests and decreased growth resumptions, thus modifying within-tree shoot demography in favour of short shoots. Growth cessations occurred in mild water stress conditions before any difference in stem water potential appeared. No major impact was observed on organ size. Consistently with tree ontogeny, the number of shoots that resumed growth after summer arrest decreased with years, but more in water-stressed than well-watered conditions. Conclusions Even though the impact of water stress differed slightly among cultivars, the reduction in neoformation and increase in summer arrest played a common role in apple tree morphological responses and led to stress avoidance by early reduction of tree leaf area. [ABSTRACT FROM AUTHOR]

As a drought tolerant plant, jujube ( Ziziphus jujuba Mill.) is commonly planted in Chinese semiarid Loess Plateau Region under rain-fed conditions. To evaluated the effectiveness of branch removal to conserve water resources in rain-fed jujube plantations in the region, two degrees of branch removal treatments (T1–two main branches removed; T2–one main branch removed) were compared with control treatment (none of the three main branches removed) and the effects on water use in Jujube plantations were analyzed. Sap flow was monitored (using the Granier-type thermal dissipation probes) along with meteorological factors, soil water content, vessel diameter, crown projection area and leaf area index, with soil moisture condition divided into water stress and non-water stress. Results showed that branch removal was an efficient way of conserving water resources in jujube plantations. a) It improved soil water content by reducing water loss via total evapotranspiration ( ET ) during jujube growth period. Total ET values were 452, 463 and 478 mm respectively for T1, T2 and the control treatments during jujube growth period in 2012; 408, 426 and 451 mm respectively for T1, T2 and the control treatments during jujube growth period in 2013 and 374, 381 and 392 mm respectively for T1, T2 and the control treatments during jujube growth period in 2014. b) Branch removal not only decreased transpiration per unit ground area (stand transpiration: T g ), but also increased the sensitivity of T g to environmental variables. In contrast, the removal of two (out of three) branches increased transpiration per unit leaf area (leaf transpiration: T l ), making it less sensitive to soil water content. c) Treatment T1 significantly increased the sensitivity of canopy conductance ( G c ) to vapor pressure deficit ( VPD ), which effect was not significant under T2. Isohydric regulation of water loss through G c response to VPD was the same for the three treatments, regardless of the different tree canopy sizes and soil water conditions, but reference canopy conductance ( G cref : canopy conductance at VPD = 1 kPa) was treatment-specific. d) Branch removal improved the tolerant of jujube tree to negative water potential and xylem cavitation by decreasing average vessel lumen diameters. Compared with the control, both branch removal treatments (T1 and T2) resulted in a significant decrease in average vessel lumen diameter at 15 mm below the cambium (40.74, 42.53 and 46.81 μm respectively for T1, T2 and the control treatments). Similarly, T1 and T2 reduced mean vessel lumen diameter at 5 mm below the cambium (43.20, 47.44 and 48.39 μm respectively for T1, T2 and the control treatments). e) Branch removal significantly decreased the fresh fruit yield and water use efficiency except in 2013, during which differences were not significant. Fresh fruit yield values were 8082, 8964 and 11293 kg ha −1 respectively for T1, T2 and the control treatments in 2012; 5691, 5426 and 6000 kg ha −1 respectively for T1, T2 and the control treatments in 2013; 6804, 8341 and 10589 kg ha −1 respectively for T1, T2 and the control treatments in 2014. WUE values were 1.79, 1.94 and 2.36 kg m −3 in 2012; 1.40, 1.28 and 1.33 kg m −3 in 2013; 1.82, 2.19 and 2.70 kg m −3 in 2014. T1 treatment was recommended in terms of improving soil water storage as well as maintaining a certain amount of productivity in jujube plantations in Chinese semiarid Loess Plateau Region. The result of the study is critical for the development of effective water management strategies in jujube plantations ensure that the fragile ecology of the Loess Plateau is sustained. [ABSTRACT FROM AUTHOR]

In order to select suitable evapotranspiration (ET) models for rainfed and sparsely cultivated jujube ( Ziziphus jujuba Mill.) plantations in the Loess Plateau, this study used Bayesian analysis to compare the performances (accuracies and uncertainties) of the Shuttleworth–Wallace (SW) model, the Penman–Monteith (PM) model and the Penman–Monteith equation with a variable surface canopy resistance (PMv) model in terms of daily and hourly ET. To determine seasonal variations and soil water dependence, probabilistic analyses were independently used to calibrate the SW and PM model parameters at every growth stages and the PMv model parameters for different soil water conditions in the growth season of rainfed jujube plantations in 2013. Finally, data for the growth season in 2012 were used to validate the calibrated models. The results showed that the posterior distributions of the parameters of the three models narrowed down at both daily and hourly scales, suggesting decreasing uncertainties in the parameters. Some model parameters varied with season (increasing for the last two growth seasons) or soil water condition (decreasing with increasing soil moisture). The performances of the ET models also varied with time scale, generally less precise at hourly than at daily time scale. Irrespectively, the three ET models met the evaluation criteria (mean relative error (MAE) < 20% and coefficient of determination ( R 2 ) > 0.8 and Willmott index of agreement ( D ) > 0.8) with acceptable accuracy and uncertainty at the daily time scale in both calibration (with R 2 , MAE and D values of 0.94, 6.78% and 0.94 for the SW model; 0.94, 7.52% and 0.94 for the PM model; and 0.89, 8.49% and 0.83 for the PM V model, respectively) and validation periods (with R 2 , MAE and D values of 0.94, 5.77% and 0.92 for the SW model; 0.93, 5.15% and 0.91 for the PM model; and 0.89, 10.26% and 0.86 for the PM V model, respectively). Where only climate data were available, the PM V model was recommended for estimation of daily ET in the study area due to less complexity, low data requirements, and high accuracy. Where sufficient monitoring data were available, the PM model was preferred for estimation of the daily ET in the study area due to less complexity and small differences in performance with the SW model. All three models met the evaluation criteria for calibration period(with R 2 , MAE and D values of 0.92, 16.04% and 0.92 for the SW model; 0.96, 14.37% and 0.94 for the PM model; and 0.89, 18.56% and 0.91 for the PM V model, respectively) while only the SW model met the evaluation criteria for validation period (with R 2 , MAE and D values of 0.87, 16.33% and 0.88 for the SW model; 0.85, 20.70% and 0.85 for the PM model; and 0.85, 23.95% and 0.83 for the PM V model, respectively) at the hourly time scale. Based on model accuracy and uncertainty at the hourly time scale, the SW model was recommended for use in estimating ET in jujube plantations in the Loess Plateau. [ABSTRACT FROM AUTHOR]

Highlights: [•] Jujube, a drought tolerant plant which was seldom studied, was used as material. [•] Water-use strategy of rainfed jujube characterized by dry climate was researched. [•] Relative sap flow (SF R ), rather than absolute sap flow (SF) was used. [•] The changing process of SF R in a day contains two different periods. [•] Soil water content mainly influence the first period of SF R changing process. [Copyright &y& Elsevier]

A recoverable photo-polymerization catalyst based on an imidazolium and a polyoxometalate, viz., (BMIm)2(DMIm)PW12O40 (where, BMIm = 1-butyl-3-methylimidazolium, DMIm = 3,3′-dimethyl-1,1′-diimidazolium) is reported. It catalyzes photo-polymerization of several industrially important monomers like styrene, methyl methacrylate, butyl methacrylate and vinyl acetate. The catalyst is recoverable and hence can be reused. The molecular weight and polydispersity index can be controlled reasonably and a reaction pathway is proposed. The synthesis of this novel catalyst is reported and the catalyst has been characterized using standard techniques such as single crystal X-ray diffraction studies, cyclic voltammetry and various spectroscopic methods such as Fourier transform infrared spectroscopy, 1H NMR spectroscopy, EPR spectroscopy and UV-Vis spectroscopy. DFT calculations have been used to explain the catalyst's photo-chemical activity. [ABSTRACT FROM AUTHOR]

Supramolecular thermo aero-able gelators (STAGs): tartaric acid, urea, and guanidine with carboxylic amide and imine moieties, respectively, as supramolecular synthons are introduced to cross-link and aerate (‘aero-able’) polyacrylate networks for synthesis of hydrogels. They are bi-functional, and hence present a greener alternative to the existing cross-linkers and gelators. [ABSTRACT FROM AUTHOR]

Self-reactive B cell progenitors are eliminated through central tolerance checkpoints, a process thought to be restricted to the bone marrow in mammals. Here, we identified a consecutive trajectory of B cell development in the meninges of mice and non-human primates. The meningeal B cells were located predominantly at the dural sinuses, where endothelial cells expressed essential niche factors to support B cell development. Parabiosis experiments together with lineage tracing showed that meningeal developing B cells were replenished continuously from hematopoietic stem cell (HSC)-derived progenitors via a circulation-independent route. Autoreactive immature B cells that recognized myelin oligodendrocyte glycoprotein (MOG), a central nervous system-specific antigen, were eliminated specifically from the meninges. Furthermore, genetic deletion of the Mog gene restored the self-reactive B cell population in the meninges. These findings identify the meninges as a distinct reservoir for B cell development, allowing in situ negative selection to ensure a locally non-self-reactive immune repertoire. [Display omitted] • Early developing B cells are present in the meninges of mice and non-human primates • HSC-derived progenitors in the skull replenish meningeal developing B cells • CNS-reactive immature B cells are eliminated specifically from the meninges • Genetic deletion of Mog restores the self-reactive B cell population in the meninges Self-reactive B cell progenitors are eliminated through central tolerance checkpoints, a process thought to be restricted to the bone marrow. Wang et al. show that developing B cells in the meninges undergo a central nervous system (CNS) antigen-dependent checkpoint to prevent autoreactive B cells from accumulating at the CNS borders. [ABSTRACT FROM AUTHOR]

Understanding variations in sap flow rates and the environmental factors that influence sap flow is important for exploring grape water consumption patterns and developing reasonable greenhouse irrigation schedules. Three irrigation levels were established in this study: adequate irrigation (W1), moderate deficit irrigation (W2) and deficit irrigation (W3). Grape sap flow estimation models were constructed using partial least squares (PLS) and random forest (RF) algorithms, and the simulation accuracy and stability of these models were evaluated. The results showed that the daily mean sap flow rates in the W2 and W3 treatments were 14.65 and 46.94% lower, respectively, than those in the W1 treatment, indicating that the average daily sap flow rate increased gradually with an increase in the irrigation amount within a certain range. Based on model error and uncertainty analyses, the RF model had better simulation results in the different grape growth stages than the PLS model did. The coefficient of determination and Willmott's index of agreement for RF model exceeded 0.78 and 0.90, respectively, and this model had smaller root mean square error and d-factor (evaluation index of model uncertainty) values than the PLS model did, indicating that the RF model had higher prediction accuracy and was more stable. The relative importance of the model predictors was determined. Moreover, the RF model more comprehensively reflected the influence of meteorological factors and the moisture content in different soil layers on the sap flow rate than the PLS model did. In summary, the RF model accurately simulated sap flow rates, which is important for greenhouse grape irrigation. [ABSTRACT FROM AUTHOR]