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يناقش الكتاب دمج تقنية البلوك تشين مع الإنترنت من الأشياء (IoT) لتشكيل ما يعرف بـB‑IoT، مركزا على البنية المعمارية، وأهم التقنيات، وقضايا الأمن والخصوصية في أنظمة IoT، ثم يستعرض التطبيقات العملية مثل خدمات ربط المركبات بالشبكة، وتبادل الكهرباء في السيارات، ومشاركة الركوب والتوثيق الإلكتروني عبر بلوك تشين. يحتوي على إطار تصميم نموذجي، ومشاريع تطبيقية (مثل محاكاة شبكة Ethereum محلية، وتطبيقات في سلسلة التوريد والتجارة التعاونية) يدمج بين الجوانب النظرية والعملية ليمنح الباحثين والمتخصصين فهما عميقا لكيفية استخدام البلوك تشين لتعزيز اللامركزية، الموثوقية، العدم قابلية التعديل، وقابلية التدقيق في نظم IoT، مع عرض اتجاهات مستقبلية ومجالات بحث واعدة في المجال.

The spatial distribution of mare basalts, titanium and KREEP (potassium, rare earth elements and phosphorus) on the Moon is asymmetrical between the nearside and farside. These asymmetries cannot be readily explained by solidification of a global magma ocean and subsequent mantle overturn, which should result in a layered and spherically symmetric lunar interior. Alternative scenarios have been proposed to explain the observed compositional asymmetry, but its origin remains enigmatic. Here, we present hydro- and mantle convection numerical simulations of the giant impact event that formed the South Pole–Aitken basin—the largest impact basin on the Moon—and the subsequent impact-induced convection with the assistance of gravitational instability. We find that the impact induces thermochemical instabilities that drive the dense KREEP-rich ilmenite-bearing cumulate to migrate towards the nearside following lunar magma ocean solidification. This results in the formation of a chemical reservoir under the nearside crust that could explain the observed geochemical asymmetries. We suggest that enrichments of ilmenite and KREEP in the nearside hemisphere following the South Pole–Aitken impact event provide a viable explanation for the wide composition range of mare basalts observed on the lunar surface. The compositional asymmetry between the Moon’s near- and farsides can be explained as the result of impact-induced mantle convection and gravitational instability, according to numerical modelling of the South Pole–Aitken impact and the ensuing mantle evolution.

China's Chang'e‐6 (CE‐6) mission has returned the first‐ever lunar farside samples from a mare plain on the southern Apollo basin floor. The crater statistics of the CE‐6 mare unit and the provenance of the samples are crucial in interpreting the CE‐6 sample analysis results and re‐calibrating the crater chronology function. Here, we conduct a thorough survey of the formation sequence and main source craters of ejecta materials at the sampling area. Our results show that the sampling mare unit has a model age of ∼2.8 Ga and the CE‐6 scooped and drilled samples mainly come from the proximal ejecta of nearby small craters and the local regolith. The total abundance of foreign (non‐mare) materials, primarily from Chaffee S and Vavilov craters, is ∼9.3%. The Chaffee S ejecta may contain lunar upper mantle materials previously excavated by the South Pole‐Aitken impact, which will shed light on the materials of the Moon's interior. Plain Language Summary In June 2024, China's Chang'e‐6 probe successfully returned the first‐ever lunar farside samples of 1,935.3 g, from the Apollo basin within the South Pole Aitken (SPA) basin, the largest, deepest, and oldest impact basin on the Moon. The age and sources of the samples are vital in understanding the geological history of the landing region and the whole Moon. In this study, we obtain the model ages of the Chang'e‐6 mare unit by impact crater statistics and conduct a thorough survey of the foreign ejecta materials from nearby and distal crater ejecta. We find that the Chang'e‐6 scooped and drilled samples are mainly from the proximal ejecta of nearby small craters and the local regolith, both having a dominant composition of intermediate‐Ti mare basalts. The surface age of the Chang'e‐6 mare unit is ∼2.8 billion years from crater density measurements, which can facilitate the refinement of lunar chronology function. Foreign (non‐mare) materials likely account for a minor fraction (∼9.3%) of the returned samples, primarily from Chaffee S and Vavilov craters. The Eratosthenian‐aged Chaffee S crater may have delivered lunar upper mantle materials previously excavated by the SPA impact, which could potentially be recognized in the Chang'e‐6 samples. Key Points The Chang'e‐6 scooped samples are predominantly from local ejecta, and the drilled samples mostly originate from local ejecta and regolith Both samples are mainly composed of local basalts, with a model age of ∼2.8 Ga, and foreign materials make up a minor fraction (∼9.3%) Chaffee S crater delivered the most foreign materials, which may contain deep‐seated materials and be collected by the Chang'e‐6 mission

Agricultural tourism aims to facilitate the sharing of agricultural knowledge and cultural traditions through planned visits. Due to the diversity in visitor interactions and comments, measuring and forecasting the quality of tourist experiences remains a problem despite its promise. In response to this issue, this research builds a prediction model for agricultural tourism experience quality assessment using big data and the Internet of Things (ATEQA-BD-IoT). The model analyses visitor data, such as feedback, engagement levels, and knowledge gain, to forecast happiness and subsequent engagement. The approach improves the precision of experience evaluations by employing reward-based learning strategies. The outcomes show that the suggested approach successfully combines behavioural data with tourist input to generate trustworthy forecasts of tourism quality. Insightful judgments and individualized services that fulfill tourist expectations and promote sustainable tourism practices are made possible by the results, which have real-world implications for enhancing agricultural tourism experiences.

Quantum anomalous Hall goes intrinsicQuantum anomalous Hall effect—the appearance of quantized Hall conductance at zero magnetic field—has been observed in thin films of the topological insulator Bi2Se3 doped with magnetic atoms. The doping, however, introduces inhomogeneity, reducing the temperature at which the effect occurs. Two groups have now observed quantum anomalous Hall effect in intrinsically magnetic materials (see the Perspective by Wakefield and Checkelsky). Serlin et al. did so in twisted bilayer graphene aligned to hexagonal boron nitride, where the effect enabled the switching of magnetization with tiny currents. In a complementary work, Deng et al. observed quantum anomalous Hall effect in the antiferromagnetic layered topological insulator MnBi2Te4.Science, this issue p. 900, p. 895; see also p. 848In a magnetic topological insulator, nontrivial band topology combines with magnetic order to produce exotic states of matter, such as quantum anomalous Hall (QAH) insulators and axion insulators. In this work, we probe quantum transport in MnBi2Te4 thin flakes—a topological insulator with intrinsic magnetic order. In this layered van der Waals crystal, the ferromagnetic layers couple antiparallel to each other; atomically thin MnBi2Te4, however, becomes ferromagnetic when the sample has an odd number of septuple layers. We observe a zero-field QAH effect in a five–septuple-layer specimen at 1.4 kelvin, and an external magnetic field further raises the quantization temperature to 6.5 kelvin by aligning all layers ferromagnetically. The results establish MnBi2Te4 as an ideal arena for further exploring various topological phenomena with a spontaneously broken time-reversal symmetry.

Summary The WUSCHEL‐related homeobox (WOX) transcription factors WOX11 and WOX12 regulate adventitious rooting and responses to stress. The underlying physiological and molecular regulatory mechanisms in salt stress tolerance remain largely unexplored. Here, we characterized the roles of PagWOX11/12a from 84K poplar (Populus alba × P. glandulosa) and the underlying regulatory mechanism in salt stress. PagWOX11/12a was strongly induced by salt stress in roots. Overexpression of PagWOX11/12a in poplar enhanced salt tolerance, as evident by the promotion of growth‐related biomass. In contrast, salt‐treated PagWOX11/12a dominant repression plants displayed reduced biomass growth. Under salt stress conditions, PagWOX11/12a‐overexpressed lines showed higher reactive oxygen species (ROS) scavenging capacity and lower accumulation of hydrogen peroxide (H2O2) than non‐transgenic 84K plants, whereas the suppressors displayed the opposite phenotype. In addition, PagWOX11/12a directly bound to the promoter region of PagCYP736A12 and regulated PagCYP736A12 expression. The activated PagCYP736A12 could enhance ROS scavenging, thus reducing H2O2 levels in roots under salt stress in PagWOX11/12a‐overexpressed poplars. The collective results support the important role of PagWOX11/12a in salt acclimation of poplar trees, indicating that PagWOX11/12a enhances salt tolerance through modulation of ROS scavenging by directly regulating PagCYP736A12 expression in poplar.

• Brassinosteroids have been implicated in the differentiation of vascular cell types in herbaceous plants, but their roles during secondary growth and wood formation are not well defined. • Here we pharmacologically and genetically manipulated brassinosteroid levels in poplar trees and assayed the effects on secondary growth and wood formation, and on gene expression within stems. • Elevated brassinosteroid levels resulted in increases in secondary growth and tension wood formation, while inhibition of brassinosteroid synthesis resulted in decreased growth and secondary vascular differentiation. Analysis of gene expression showed that brassinosteroid action is positively associated with genes involved in cell differentiation and cell-wall biosynthesis. • The results presented here show that brassinosteroids play a foundational role in the regulation of secondary growth and wood formation, in part through the regulation of cell differentiation and secondary cell wall biosynthesis.

Summary Adventitious roots occur naturally in many species and can also be induced from explants of some tree species including Populus, providing an important means of clonal propagation. Auxin has been identified as playing a crucial role in adventitious root formation, but the associated molecular regulatory mechanisms need to be elucidated. In this study, we examined the role of PagFBL1, the hybrid poplar (Populus alba × P. glandulosa clone 84K) homolog of Arabidopsis auxin receptor TIR1, in adventitious root formation in poplar. Similar to the distribution pattern of auxin during initiation of adventitious roots, PagFBL1 expression was concentrated in the cambium and secondary phloem in stems during adventitious root induction and initiation phases, but decreased in emerging adventitious root primordia. Overexpressing PagFBL1 stimulated adventitious root formation and increased root biomass, while knock‐down of PagFBL1 transcript levels delayed adventitious root formation and decreased root biomass. Transcriptome analyses of PagFBL1 overexpressing lines indicated that an extensive remodelling of gene expression was stimulated by auxin signalling pathway during early adventitious root formation. In addition, PagIAA28 was identified as downstream targets of PagFBL1. We propose that the PagFBL1‐PagIAA28 module promotes adventitious rooting and could be targeted to improve Populus propagation by cuttings.

Hybrid poplars are industrial trees in China. An understanding of the molecular mechanism underlying wood formation in hybrid poplars is necessary for molecular breeding. Although the division and differentiation of vascular cambial cells is important for secondary growth and wood formation, the regulation of this process is largely unclear. In this study, OE and transgenic poplars were generated to investigate the function of . RNA-seq and qRT-PCR were conducted to analyze genome-wide gene expression, while ChIP‒seq and ChIP-PCR were used to identified the downstream genes regulated by . We report that from hybrid poplar ( × ), a growth-regulating factor, plays a critical role in the regulation of vascular cambium activity. was expressed predominantly in the cambial zone of vascular tissue. Overexpression of (the mutated version of in the target sequence) in Populus led to decreased plant height and internode number. Further stem cross sections showed that the OE plants exhibited significant changes in vascular pattern with an increase in xylem and a reduction in phloem. In addition, cambium cell files were decreased in the OE plants. However, dominant suppression of the downstream genes of using showed an opposite phenotype. Based on the RNA-seq and ChIP-seq results, combining qRT-PCR and ChIP-PCR analysis, candidate genes, such as , and , were obtained and found to be mainly involved in cambial activity and xylem differentiation. Accordingly, we speculated that functions as a positive regulator mediating xylem differentiation by repressing the expression of the and genes to set the pace of cambial activity. In contrast, mediated the GA signaling pathway by upregulating expression to stimulate xylem differentiation. This study provides valuable information for further studies on vascular cambium differentiation mechanisms and genetic improvement of the specific gravity of wood in hybrid poplars.

• Wood formation is the terminal differentiation of xylem mother cells derived from cambial initials, and negative regulators play important roles in xylem differentiation. • The molecular mechanism of the negative regulator of xylem differentiation PagKNAT2/6b was investigated. PagKNAT2/6b is an ortholog of Arabidopsis KNAT2 and KNAT6 that is highly expressed in phloem and xylem. Compared to nontransgenic control plants, transgenic poplar plants overexpressing PagKNAT2/6b present with altered vascular patterns, characterized by decreased secondary xylem with thin cell walls containing less cellulose, xylose and lignin. • RNA sequencing analyses revealed that differentially expressed genes are enriched in xylem differentiation and secondary wall synthesis functions. Expression of NAM/ATAF/CUC (NAC) domain genes including PagSND1-A1, PagSND1-A2, PagSND1-B2 and PagVND6-C1 is downregulated by PagKNAT2/6b, while PagXND1a is directly upregulated. Accordingly, the dominant repression form of PagKNAT2/6b leads to increased xylem width per stem diameter through downregulation of PagXND1a. • PagKNAT2/6b can inhibit cell differentiation and secondary wall deposition during wood formation in poplar by modulating the expression of NAC domain transcription factors. Direct activation of PagXND1a by PagKNAT2/6b is a key node in the negative regulatory network of xylem differentiation by KNOXs.