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Intercropping achieved through agroforestry is increasingly being recognized as a sustainable form of land use. In agroforestry, the roots of trees and crops are intermingled, and their interactions and the production of exudates alter the soil environment and soil microbial community. Although tree–crop interactions vary depending on the stand age of the trees, how stand age affects beneficial microorganisms, including arbuscular mycorrhizal fungi (AMF), and whether changes in soil microorganisms feed back on crop growth in agroforestry systems are unknown. We therefore conducted a long-term field study to compare changes in the soil microbial and AMF communities in a jujube/wheat agroforestry system containing trees of different stand ages: 3-year-old jujube, 8-year-old jujube, and 13-year-old jujube. Our results showed that by changing soil moisture and available phosphorus content, the stand age of the trees had a significant effect on the soil microbial and AMF communities. Soil moisture altered the composition of soil bacteria, in particular the proportions of Gram-positive and Gram-negative species, and available phosphorus had significant effects on the AMF community. A network analysis showed that older stands of trees reduced both AMF diversity and network complexity. An ordinary least squares regression analysis indicated that AMF diversity, network complexity, and stability contributed to wheat yield. Finally, structural equation modeling showed that changes in edaphic factors induced by tree age brought about significant variation in the soil microbial and AMF communities, in turn, affecting crop growth. Our study highlights the crucial roles of soil microorganisms, in particular AMF, in supporting plant growth in agroforestry systems as well as the need to consider stand age in the establishment of these systems.

Al86Ce10TM4 amorphous alloys (TM = Ti, Cr, Mn, Fe, Co, Ni and Cu; where the alloys are denoted by A1~A7, respectively) were fabricated using melt-spin fast-quenching method. The glass-forming ability (GFA), thermal stability (TS), and mechanical and corrosion behavior of the as-spun alloys were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy - energy dispersive spectroscopy (SEM-EDS), differential scanning calorimetry (DSC), micro-indentation and electrochemical techniques. It was found Al and Ce microalloyed with Ti, Cr, Mn, Fe, Co, Ni and Cu, respectively enhance glass formation, thus the as-spun Al86Ce10TM4 alloys form an amorphous matrix embedded with short range ordered (SRO) Al-TM, Al-Ce and Al-Ce-TM quasi-crystalline clusters due to a strong heteroatomic interaction related to a covalent character of atomic bonds (for A1~A7) or/and inlaid with face-centered-cubic aluminum (FCC-Al) nano-crystallites which were precipitated during the melt-spin quenching (for A1~A3). The GFA of the alloys ranks in the sequence of A4 > A5 > A6 > A7 > A2 > A3 > A1 which can be assessed by the supercooled liquid region ΔTm (=Tm-Tx), the reduced glass transition temperature Trg (=Tg/Tm), and other criteria such as γ′ = Tx/(Tg + Tm), δ′ = Tx/(Tm − Tg), β′ = TxTg/(Tm + Tx)2, and ω′ = Tm(Tm + Tx)/(Tx(Tm − Tx)); while the TS of the alloys lists in the series of A5 > A6 ~ A4 > A7 > A3 > A2 > A1 that can be evaluated by the first crystallization activation energy Ec, first crystallization activation enthalpy ΔH⁎, frequency factor Ko, fragility parameter m, and theoretical glass transition temperature Tg⁎. The hardness of the alloys A1~A7 accounts to 707, 809, 940, 863, 762, 809, and 715 MPa, respectively, attributing to a composite structure consisting of an amorphous matrix tessellated with SRO quasi-crystalline clusters or/and FCC-Al nano-crystallites. In addition, the alloys exhibit high corrosion resistance in the rate of 10−7–10−8 A/cm2 with a large passivation scope except that the alloy A7 presents a corrosion rate of 10−6 A/cm2 with an active anodic dissolution behavior. The results manifest the Al86Ce10TM4 alloys can be fabricated into a unique composite consisting of an amorphous matrix embedded with SRO quasi-crystalline or/and nano-crystalline phases which confers high mechanical hardness and corrosion resistance for potential engineering applications. Keywords: Amorphous alloys, Glass-forming ability, Thermal behavior, Al-Ce-TM, Electrochemistry

Abstract The combination of fingerprint positioning and 5G (the 5th Generation Mobile Communication Technology) offers broader application prospects for indoor positioning technology, but also brings challenges in real-time performance. In this paper, we propose a fingerprint positioning method based on a deep convolutional neural network (DCNN) using a classification approach in a single-base station scenario for massive multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems. We introduce an angle-delay domain fingerprint matrix that simplifies the computation process and increases the location differentiation. The cosine distance is chosen as the fingerprint similarity criterion due to its sensitivity to angular differences. First, the DCNN model is used to determine the sub-area to which the mobile terminal belongs, and then the weighted K-nearest neighbor (WKNN) matching algorithm is used to estimate the position within the sub-area. The positioning performance is simulated in a DeepMIMO indoor environment, showing that the classification DCNN method reduces the positioning time by 77.05% compared to the non-classification method, with only a 1.08% increase in average positioning error.

Abstract Agricultural extension, as an important part of modern agriculture, can promote the scientific transformation of the traditional agricultural production model. This paper analysed the impact of university agricultural technology extension on efficient and sustainable agriculture using difference-in-differences model (DID). The results showed that university agricultural technology extension plays a facilitating role by influencing the coordinated development and green development dimensions in efficient and sustainable agriculture; there is a moderating effect of modern agricultural industrial parked in university agricultural technology extension and efficient and sustainable agriculture; there are significant differences in the impact of university agricultural technology extension on efficient and sustainable agriculture across regions and different levels of development. The findings have important implications for evaluating the effectiveness of current university agricultural extension policies and how to further promote university agricultural extension. The study also established an evaluation index system for efficient and sustainable agriculture, explored the mechanism of university agricultural extension in promoting efficient and sustainable agriculture, and enriched relevant theoretical research.

Exosomes are 30–150 nm extracellular vesicles that are secreted by almost all types of cells. Exosomes contain a variety of biologically active substances, such as proteins, nucleic acids, and lipids, and are important in the intercellular communication of biological mediators involved in nerve injury and repair, vascular regeneration, immune response, fibrosis formation, and many other pathophysiological processes. Although it has been extensively studied in the field of cancer, the exploration of ocular diseases has only just begun. Here, we discuss the latest developments in exosomes for age-related macular degeneration (AMD), including the pathogenesis of exosomes in age-related macular degeneration, their potential as diagnostic markers, and therapeutic vectors of the disease. Finally, the study of exosomes in age-related macular degeneration is still relatively few, and more detailed basic research and clinical trials are needed to verify its application in treatment and diagnosis, so as to adopt more personalized diagnosis and treatment strategies to stop the progression of age-related macular degeneration.

Nowadays, frequent climate extremes exert a serious impact on agricultural production and social development, which is seldom studied in the previous literature. Production–Living–Ecological (PLE) is a useful analysis framework, and China is a suitable model for such study. This paper takes the Huai River Eco-Economic Belt (HREB), an important agricultural zone in China, to study the relationship among agricultural production (P), society (L), and climate change (E), which is referred to as APLE. This paper constructs a coupled coordination evaluation index system for the APLE system and uses coupling coordination degree models and geographic detector to study the spatial and temporal evolution of the coordinated development of 34 counties (cities) in the HREB from 2009 to 2018. The results show the following: (1) The development of the agricultural subsystem and the social subsystem formed a “scissors difference” from 2009 to 2014, and the three subsystems showed a slight upward trend during 2014–2018. (2) The coupling and coordinated development of the APLE system in the HREB was generally stable, and the coupling coordination degree was improved from low-grade and slightly uncoordinated to barely and primarily coordinated. Furthermore, the spatial differentiation of the coupling coordination degree shows a clear pattern of being high in the southeast and low in the northwest. (3) The main influencing factors are the drought and flood protection rate, the effective irrigation rate, the per capita electricity consumption in agriculture, the number of beds in healthcare facilities per 10,000 people, the per capita disposable income of urban residents, the annual average temperature, and the annual precipitation. (4) The spatial–temporal evolution of the coupling and coordinated development of the APLE system is the result of the comprehensive effect of internal driving forces such as food security, the consumption level of rural residents, and the development level of urbanization construction, and external driving forces such as government public welfare and natural conditions.