Irrigation and nitrogen fertiliser optimisation in protected vegetable fields of northern China:Achieving environmental and agronomic sustainability

Globally,sub-optimal use of nitrogen (N) fertiliser and elevated N irrigation groundwater have led to high leached nitrate (NO_(3)^(–)) losses from protected vegetable field systems.Optimising fertiliser and irrigation management in different soil types is crucial to reduce future N loads from such systems.The present 4-year study examined leached N loads from lysimeter monitoring arrays set up across 18 protected vegetable system sites encompassing the dominant soil types of northern China.The treatments applied at each field site were:1) a high N and high irrigation input treatment (HNHI);2) a low N but high irrigation input treatment (LNHI) and 3) a low N with low irrigation input treatment (LNLI).Results showed that the mean annual leached total nitrogen loads from the HNHI,LNHI and LNLI treatments were 325,294 and 257 kg N ha^(–1) in the fluvo-aquic soil,114,100 and 78 kg N ha^(–1) in the cinnamon soil and 79,68 and 57 kg N ha^(–1) in the black soil,respectively.The N dissolved in irrigation water in the fluvo-aquic soil areas was 8.26-fold higher than in the cinnamon areas.A structural equation model showed that N fertiliser inputs and leaching water amounts explained 14.7 and 81.8%of the variation of leached N loads,respectively.Correspondingly,reducing irrigation water by 21.5%decreased leached N loads by 20.9%,while reducing manure N and chemical N inputs by 22 and 25%decreased leached N loads by only 9.5%. This study highlights that protected vegetable fields dominated by fluvo-aquic soil need management to curtail leached N losses in northern China.

Opportunity and shift of nitrogen use in China

It is never an easy task for China to feed 1.4 billion people with only 7%of the world's arable land.With nearly 30%of the world's nitrogen(N)fertilizer applied,China achieves high crop yields while facing N pollution result-ing from excessive N input.Here,we calculate the farmland N budget on the national and regional scales.The N use efficiency(NUE)in China increased by 28.0%during 2005-2018.This improvement is due to the reduction in fertilization and the improvement of crop management.The fragmented farmland is changing to large-scale farmland with the increase in cultivated land area per rural population and the development of agricultural mech-anization.This opportunity brings more possibilities for precision farmland management,thus further improving NUE.The goal of an NUE of 0.6 may be achieved in the 2040s based on the current development trend.This striking N use shift in China has important implications for other developing countries.

A precision-drive hysteresis model with an equal-density weight function for GMA feedforward compensation

Giant magnetostrictive actuators(GMAs) are a widely used type of micro-nano actuator, and they are greatly significant in the field of precision engineering. The accuracy of a GMA often depends on its hysteresis model. However, existing models have some limitations,including the difficulty of identifying their parameters and the tradeoff between the quantity of modeling data required and the level of precision achieved. To solve these problems, in this paper, we propose a Preisach inverse model based on equal-density segmentation of the weight function(E-Preisach). The weight function used to calculate the displacement is first discretized. Then, to obtain a finer weight distribution, the discretized geometric units are uniformly divided by area. This can further minimize the output displacement span, and it produces a higher-precision hysteresis model. The process of parameter identification is made easier by this approach, which also resolves the difficulty of obtaining high precision using a small amount of modeling data. The Preisach and the E-Preisach inverse models were investigated and compared using experiments. At frequencies of 1 and 5 Hz, it was found that the E-Preisach inverse model decreases the maximum error of the feedforward compensation open-loop control to within 1 μm and decreases the root-mean-square error in displacement to within0.5 μm without the need to increase the number of measured hysteresis loops. As a result, the E-Preisach inverse model streamlines the structure of the model and requires fewer parameters for modeling. This provides a high-precision modeling method using a small amount of modeling data;it will have applications in precision engineering fields such as active vibration damping and ultra-precision machining.

MEC-IoT-Healthcare: Analysis and Prospects

Physical sensors,intelligent sensors,and output recommenda-tions are all examples of smart health technology that can be used to monitor patients’health and change their behavior.Smart health is an Internet-of-Things(IoT)-aware network and sensing infrastructure that provides real-time,intelligent,and ubiquitous healthcare services.Because of the rapid development of cloud computing,as well as related technologies such as fog computing,smart health research is progressively moving in the right direction.Cloud,fog computing,IoT sensors,blockchain,privacy and security,and other related technologies have been the focus of smart health research in recent years.At the moment,the focus in cloud and smart health research is on how to use the cloud to solve the problem of enormous health data and enhance service performance,including cloud storage,retrieval,and calculation of health big data.This article reviews state-of-the-art edge computing methods that has shifted to the collection,transmission,and calculation of health data,which includes various sensors and wearable devices used to collect health data,various wireless sensor technologies,and how to process health data and improve edge performance,among other things.Finally,the typical smart health application cases,blockchain’s application in smart health,and related privacy and security issues were reviewed,as well as future difficulties and potential for smart health services.The comparative analysis provides a reference for the the mobile edge computing in healthcare systems.

艾灸治疗强直性脊柱炎的分子作用机制研究进展

艾灸作为中医护理技术的重要组成部分,在改善强直性脊柱炎(ankylosing spondylitis,AS)症状方面作用独特,艾灸干预AS的机制研究主要集中在抗炎、免疫调节、骨代谢调节、肠道菌群调节等方面。分子医学对进一步阐明艾灸干预AS的机制具有重要意义。但艾灸干预AS的分子机制研究仍存在一些问题:现有的生物医学研究方法仅从某一特定单一领域进行探索,缺乏基于生物医学网络的艾灸靶向分子的探索,今后可借助组学技术、构建组学间生物信息交互网络,整体、系统地探讨艾灸对AS的分子网络作用;艾灸对上游成骨转录因子及相关信号通路WNT、β-catenin和BMP/Smads等的影响尚未明确,今后的研究可着眼于骨重建的相关信号靶点,阐明艾灸抗新骨形成的机制;此外,缺乏从代谢物的角度阐明艾灸治疗AS的分子机制研究,需进一步借助代谢组学技术,更加系统地探索艾灸治疗AS的机制。

Comparison of social interaction and neural activation in the main olfactory bulb and the accessory olfactory bulb between Microtus mandarinus and Microtus fortis

To gain insight into the function of AOB and MOB during different social interaction and in different vole species,the behaviors and neural activation of the olfactory bulbs in social interactions of mandarin voles Microtus mandarinus and reed voles Microtus fortis were compared in the present research.Mandarin voles spent significantly more time attacking and sniffing their opponents and sniffing sawdust than reed voles.During same sex encounters,mandarin voles attacked their opponents for a significantly longer time and sniffed its opponent for shorter time compared with male-female interactions.However,no significant behavioral differences were found during encounters of two individual reed voles,regardless of gender composition of the pair.Using c-Fos as an indicator of neural activation,we observed that neural activation was significantly higher in almost all sub-regions of the main olfactory bulb(MOB)and the accessory olfactory bulb(AOB)of mandarin voles compared with reed voles.Numbers of c-Fos-ir neurons in almost all sub-regions of the AOB and the MOB during male-female interactions were also higher than those in interactions of the same sex.Anterior-posterior ratios of Fos-ir neurons in the AOBM(AOBMR)and the AOBG(AOBGR)in male-female interaction were significantly higher than those in interaction of the same sex.The AOBMR of male mandarin voles and reed voles were larger than those of females in male-female interactions.Behavioral patterns are consistent with cellular activity patterns.Consistent level of neural activation in MOB and AOB suggests important roles of both the main olfactory bulb and the accessory olfactory bulb in social interaction in two species.

Quantum dots induce hot-start effects for Taq-based polymerase chain reaction

Decent hot-start effects were here reported in Taq DNA polymerase-based polymerase chain reaction (PCR) when water-soluble CdTe quantum dots (QDs) were employed. The hot-start effects were revealed by the higher amplicon yields and distinguished suppression of nonspecific amplification after pre-incubation of PCR mix with quantum dots between 30°C and 56°C. DNA targets were well amplified even after PCR mixture was pre-incubated 3 hr at 30°C or 1 hr at 50°C. Importantly, the effects of QDs nanoparticles could be reversed by increasing the polymerase concentration, suggesting that there was an interaction between QDs and Taq DNA polymerase. Moreover, control experiment indicated that hot-start effect is not primarily due to the reduced polymerase concentration resulted from the above interaction. This study provided another good start to investigate potential implications of quantum dots in key molecular biology techniques.

Determination of the surface states from the ultrafast electronic states in a thermoelectric material

We reveal the electronic structure in Yb Cd_(2)Sb_(2),a thermoelectric material,by angle-resolved photoemission spectroscopy(ARPES)and time-resolved ARPES(tr ARPES).Specifically,three bulk bands at the vicinity of the Fermi level are evidenced near the Brillouin zone center,consistent with the density functional theory(DFT)calculation.It is interesting that the spin-unpolarized bulk bands respond unexpectedly to right-and left-handed circularly polarized probe.In addition,a hole band of surface states,which is not sensitive to the polarization of the probe beam and is not expected from the DFT calculation,is identified.We find that the non-equilibrium quasiparticle recovery rate is much smaller in the surface states than that of the bulk states.Our results demonstrate that the surface states can be distinguished from the bulk ones from a view of time scale in the nonequilibrium physics.

Histological Architecture of the Nasal Region in Rana chensinensis

The nasal region of Rana chensinensis is divided into the nasal capsules and nasal cavities. In this study, we investigated the adult histological structure of the nasal capsules and nasal cavities in the frog R. chensinensis under the microscope. We found that an eminentia olfactoria is present in this frog and the presence of the eminentia olfactoria may be connected to a terrestrial life style. The double staining method using alcian blue and alizarin red showed that the septomaxilla, the most important bone associated with the olfactory capsules, is an intramembranous bone in R. chensinensis. The opening of the nasolacrimal duct showed a close proximity to the apertura nasalis externa. The presence of the nasolacrimal duct in the olfactory region may be an adaptation to a terrestrial environment. The function of the vomeronasal and olfactory organs is discussed in the paper.

高校办公室现代化治理的路径探究

党的十九届四中全会为我国高等教育发展指明了方向,完善高校管理制度是建设中国特色社会主义现代化高校的基石。随着现代化脚步不断向前迈进,高校管理应从"管"上升为"治",形成自我管理、自我服务的优质体系,在这个管理体系中办公室是一个不可或缺的重要纽带。文章探讨现代化高校建设的有效提升途径,为建设现代化高水平高校提供有效方法。

Environmental benefits and farmers' adoption of winter cover crops in the North China Plain

The introduction of cover crops into monoculture systems to improve soil health has been widely adopted worldwide. However, little is known about the environmental risks and application prospects of different cover crops in spring maize(Zea mays L.) monocultures proposed in the North China Plain. A pot experiment was conducted to evaluate the effects of different winter cover crops on subsequent maize yield, soil fertility, and environmental risks of nitrogen(N) loss, and a questionnaire survey was conducted to examine factors influencing farmers' willingness to adopt cover crops in the North China Plain. Based on the same fertilization regime during the maize growing period, four winter cover crop treatments were set up, including bare fallow, hairy vetch(Vicia villosa Roth.), February orchid(Orychophragmus violaceus), and winter oilseed rape(Brassica campestris L.). The results indicated that winter cover crops significantly increased subsequent maize yield and soil organic carbon, total N, and microbial biomass carbon and N compared with the bare fallow treatment.The incorporation of cover crops led to a negligible increase in nitrous oxide(N_(2)O) emissions and had a very limited effect on ammonia(NH_(3)) emissions.The incorporation of February orchid and winter oilseed rape decreased nitrate leaching compared with the hairy vetch treatment in the maize growing season.The N losses via N_(2)O and NH_(3) emissions and N leaching accounted for 71%–84% of the N surplus. However, yield increase and environmental benefits were not the main positive factors for farmers to accept cover crops. Financial incentive was rated by 83.9% of farmers as an “extremely important” factor, followed by other costs, when considering winter cover cropping. These results indicate that the environmental benefits depend on the type of cover crop. Maintaining high levels of soil fertility and maize yield, providing sufficient subsidies, and encouraging large-area cultivation of cover crops are critical measures to promote winter cover cropping in the North China Plain.

Combined organic-inorganic fertilization builds higher stability of soil and root microbial networks than exclusive mineral or organic fertilization

Plant health and performance are highly dependent on the root microbiome.The impact of agricultural management on the soil microbiome has been studied extensively.However,a comprehensive understanding of how soil types and fertilization regimes affect both soil and root microbiome is still lacking,such as how fertilization regimes affect the root microbiome's stability,and whether it follows the same patterns as the soil microbiome.In this study,we carried out a longterm experiment to see how different soil types,plant varieties,and fertilizer regimens affected the soil and root bacterial communities.Our results revealed higher stability of microbial networks under combined organic-inorganic fertilization than those relied solely on inorganic or organic fertilization.The root microbiome variation was predominantly caused by total nitrogen,while the soil microbiome variation was primarily caused by pH and soil organic matter.Bacteroidetes and Firmicutes were major drivers when the soil was amended with organic fertilizer,but Actinobacteria was found to be enriched in the soil when the soil was treated with inorganic fertilizer.Our findings demonstrate how the soil and root microbiome respond to diverse fertilizing regimes,and hence contribute to a better understanding of smart fertilizer as a strategy for sustainable agriculture.

反铁磁拓扑绝缘体MnBi_(2)Te_(4)/Bi_(2)Te_(3)超晶格具有不变近零能隙的表面态研究

磁性拓扑材料蕴含拓扑磁电效应等丰富拓扑物理现象,成为近年来拓扑量子材料研究热点.最近,在本征反铁磁拓扑绝缘体MnBi_(2)Te_(4)中发现了量子反常霍尔效应及轴子绝缘体态,使得此体系引发了广泛的关注.由MnBi_(2)Te_(4)及Bi_(2)Te_(3)插层得到的超晶格结构材料(MnBi_(2)Te_(4))m(Bi_(2)Te_(3))n,同样具有本征反磁序及非平庸拓扑相,为研究磁性与拓扑电子结构相互关系提供了重要的可调控材料平台.本文利用具有空间分辨能力的激光和同步辐射角分辨光电子能谱系统(ARPES),全面且系统地测量了此材料体系中Mn Bi4Te7的电子结构,发现在MnBi2Te4及Bi2Te3解理面均存在近零能隙的拓扑表面态;文章通过变温测量,发现其体态电子受到反铁磁序的强烈影响,但其拓扑表面态在反铁磁相变时保持近零能隙不变.这些结果印证了MnBi2Te4体系的不变近零能隙的普遍性,为理解中磁性与拓扑物态之间相互作用以及其调控提供了重要的谱学信息.

Spatial and seasonal variations in bacterial communities of the Yellow Sea by T-RFLP analysis

Four typical coastal sites(rocky shore,sandy shore,mud flat shore,and artificial harbor)at the Yellow Sea were chosen to investigate the spatial and seasonal variations in bacterial communities.This was accomplished by using terminal restriction fragment length polymorphism(T-RFLP)analysis of PCR amplified 16S rDNA fragments.Two kinds of tetrameric restriction enzymes,HhaI and MspI,were used in the experiment to depict the bacterial community diversity in different marine environments.It was found that the community compositions digested by the two enzymes separately were different.However,the results of bacterial community diversity derived from them were similar.The MDA analysis results of T-RFLP profiles coming from HhaI and MspI both exhibited a significant seasonal community shift for bacteria and a relatively low spatial variation among the four locations.With HhaI as the sample,the pair wise Ttests also revealed that variations were minor between each pair of marine environments,with R ranging from 0.198 to 0.349.However,the bacterial community structure in the mud flat site depicted a larger difference than each of the other three sites(R ranging from 0.282 to 0.349).

Experimental evaluation of temperature distribution of a vapor cell using a Hilbert transform procedure

A diode-pumped alkali vapor laser(DPAL) is one of the most promising candidates of the next-generation high-powered laser source. As the saturated number density of alkali vapor is highly dependent on the temperature inside a vapor cell,the temperature distribution in the cross-section of a cell will greatly affect the homogeneity of a laser medium and the output characteristics of a DPAL. In this paper, we developed an algorithm based on the regime concluding quasi-Hilbert transform to evaluate the phase aberration of a wavefront when the probe beam passes through the vapor cell placed in one arm of a Mach–Zehnder interference setup. According to the theoretical algorithm, we deduced the temperature distribution of a cesium vapor cell for different heating conditions. The study is thought to be useful for development of a high-powered laser.

Deleterious processes of a diode-pumped cesium vapor hollow-core photonic-crystal fiber laser

A diode-pumped alkali laser(DPAL) provides the significant promise for high-powered performances. In this paper, a mathematical model is introduced for examination of the kinetic processes of a diode-pumped cesium vapor hollow-core photonic-crystal fiber(HC-PCF) laser, in which the cesium vapor is filled in the center hole of a photonic-bandgap fiber instead of a glass cell. The influence of deleterious processes including energy pooling, photo-ionization, and Penning ionization on the physical features of a fiber DPAL is studied in this report. It has been theoretically demonstrated that the deleterious processes cannot be ignored in a high-powered fiber-DPAL system.

Filtering and regret network for spacecraft component segmentation based on gray images and depth maps

Identifying and segmenting spacecraft components is vital in many on-orbit space missions,such as on-orbit maintenance and component recovery.Integrating depth maps with visual images has been proven effective in improving segmentation accuracy.However,existing methods ignore the noise and fallacy in collected depth maps,which interfere with the network to extract representative features,decreasing the final segmentation accuracy.To this end,this paper proposes a Filtering and Regret Network(FRNet)for spacecraft component segmentation.The FRNet incorporates filtering and regret mechanisms to suppress the abnormal depth response in shallow layers and selectively reuses the filtered cues in deep layers,avoiding the detrimental effects of low-quality depth information while preserving the semantic context inherent in depth maps.Furthermore,a two-stage feature fusion module is proposed,which involves information interaction and aggregation.This module effectively explores the feature correlation and unifies the multimodal features into a comprehensive representation.Finally,a large-scale spacecraft component recognition dataset is constructed for training and evaluating spacecraft component segmentation algorithms.Experimental results demonstrate that the FRNet achieves a state-of-the-art performance with a mean Intersection Over Union(mIOU)of 84.13%and an average inference time of 133.2 ms when tested on an NVIDIA RTX 2080 SUPER GPU.