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Characteristics of soil quality attributes under different agroecosystems and its implications for agriculture in the Choke Mountain watershed in Ethiopia

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Frontiers of Agricultural Science and Engineering 2024年第2期11卷 303-313页

作者： Demeku MESFIN Engdawork ASSEFA Belay SIMANE College of development studies Center for Environment and DevelopmentAddis Ababa UniversityAddis Ababa 1000Ethiopia College of Social Science and Humanities Department of Geography and Environmental StudiesWolaita Sodo UniversityWolaita Sodo 4620Ethiopia

Awareness of how soil properties vary over agroecosystems(AES) is essential for understanding soil potentials and improving site-specific agricultural management strategies for a sustainable ecosystem. This study examined the characteristics of soil quality attributes and implications for agriculture in the Choke Mountain watershed in Ethiopia. Forty-seven composite soil samples(0–20 cm deep) were collected from lowland and valley fragmented(AES 1),midland plain with black soil(AES 2), midland plain with brown soil(AES 3),sloppy midland land(AES 4), and hilly and mountainous highlands(AES 5).Ten of 15 soil quality properties were significant(P < 0.05 or 0.01), including silt, exchangeable bases, cation exchange capacity, percent base saturation,p H, organic matter, total nitrogen and available phosphorous(P) across the five AES. However, all properties were variable with coefficients of variation from 7%(total porosity) to 169%(available P) across the AES. Although AES 2and 3 are affected by waterlogging and acidity, these two have better prospects for agriculture, but AES 1, 4, and 5 are unsuitable for agriculture because of soil erosion. Therefore, appropriate and applicable soil management strategies, particularly lime application and organic fertilizer, are fundamental to reversing soil acidity and improving soil fertility.

关键词： Agroecosystem Choke Mountain watershed coefficients of variation Ethiopia soil quality indicator

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Application of supervised machine learning to predict the enhanced gas recovery by CO2 injection in shale gas reservoirs

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Petroleum 2024年第1期10卷 124-134页

作者： Moataz Mansi Mohamed Almobarak Jamiu Ekundayo Christopher Lagat Quan Xie discipline of Petroleum Engineering WA School of Mines: Minerals Energy and Chemical Engineering Curtin University

The technique of Enhanced Gas Recovery by CO2injection（CO2-EGR） into shale reservoirs has brought increasing attention in the recent decade. CO2-EGR is a complex geophysical process that is controlled by several parameters of shale properties and engineering design. Nevertheless, more challenges arise when simulating and predicting CO2/CH4displacement within the complex pore systems of shales. Therefore,the petroleum industry is in need of developing a cost-effective tool/approach to evaluate the potential of applying CO2injection to shale reservoirs. In recent years, machine learning applications have gained enormous interest due to their high-speed performance in handling complex data and efficiently solving practical problems. Thus, this work proposes a solution by developing a supervised machine learning（ML） based model to preliminary evaluate CO2-EGR efficiency. Data used for this work was drawn across a wide range of simulation sensitivity studies and experimental investigations. In this work, linear regression and artificial neural networks（ANNs） implementations were considered for predicting the incremental enhanced CH4. Based on the model performance in training and validation sets, our accuracy comparison showed that（ANNs） algorithms gave 15% higher accuracy in predicting the enhanced CH4compared to the linear regression model. To ensure the model is more generalizable, the size of hidden layers of ANNs was adjusted to improve the generalization ability of ANNs model. Among ANNs models presented, ANNs of 100 hidden layer size gave the best predictive performance with the coefficient of determination（R2） of 0.78 compared to the linear regression model with R2of 0.68. Our developed MLbased model presents a powerful, reliable and cost-effective tool which can accurately predict the incremental enhanced CH4by CO2injection in shale gas reservoirs.

关键词： Artificial intelligence Supervised Machine Learning Shale Gas Enhanced Shale Gas Recovery CO 2 Injection CO 2 sequestration

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Sister-city Ties and Chinese Outward Foreign Direct Investment:A Spatial Econometric Analysis

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China & World Economy 2024年第1期32卷 231-258页

作者： Youxing Huang Meixia Dong Yanping Zhao School of Economics Ocean University of ChinaChina School of Economics and Marine development studies Institute Ocean University of ChinaChina

This paper employs dynamic spatial econometric methods to analyze the impact of the sister-city relationship on Chinese outward foreign direct investment(OFDI)using a linked country-level dataset from 2003 to *** results show strong and robust evidence that the sister-city relationship has been a crucial OFDI location determinant in host countries and their ***,the sister-city tie between China and the host country has stimulated Chinese OFDI in host ***,Chinese OFDI in host countries would be reduced if China concluded sister-city ties with their neighbors to which we refer as the neighboring *** mechanism tests show that sister cities have promoted OFDI in host countries via four channels:reducing political risk,decreasing information asymmetry,narrowing institutional distance,and mitigating cultural *** tendency for sister-city links to promote OFDI has varied substantially depending on OFDI entry modes(i.e.,greenfield or cross-border mergers and acquisitions),motivation(i.e.,resource-,market-,technology-,or efficiency-oriented OFDI),and Sino–foreign geographical relationships(i.e.,Belt and Road Initiative countries or other countries).

关键词： foreign direct investment location choice sister city spatial econometrics

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Conversion of a single-layer ANN to photonic SNN for pattern recognition

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Science China(Information Sciences) 2024年第1期67卷 261-270页

作者： Yanan HAN Shuiying XIANG Tianrui ZHANG Yahui ZHANG Xingxing GUO Yuechun SHI State Key Laboratory of Integrated Service Networks State Key Discipline Laboratory of Wide Bandgap Semiconductor TechnologyXidian University Yongjiang Laboratory

This work presents a complete conversion scheme for photonic spiking neural networks(SNNs).We verified that the output of an artificial neural network(ANN) trained with the simulated optical activation function can be directly converted into the spike rate of a photonic spiking neuron *** reveal the feasibility of hardware implementation,we considered the effects of different bit precisions of data and weight,noise level,and bias current mismatch on the converted *** proposed scheme was evaluated using the Deterding vowel,IRIS,TIDIGITS,and MNIST datasets for pattern recognition,and achieved mean accuracies of 95.80%,98.67%,96.19%,and 92.33%,*** proposed scheme can convert an ANN into a photonic SNN with almost no precision loss,and the performance was comparable to that of an ANN trained with the rectified linear unit *** proposed scheme can enable the high-performance implementation of photonic SNNs.

关键词： photonic SNN conversion optical computing pattern recognition artificial neural network

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Experimental and numerical demonstration of hierarchical time-delay reservoir computing based on cascaded VCSELs with feedback and multiple injections

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Science China(Information Sciences) 2024年第2期67卷 279-290页

作者： Xingxing GUO Shuiying XIANG Xingyu CAO Biling GU State Key Laboratory of Integrated Service Networks Xidian University State Key discipline Laboratory of Wide Bandgap Semiconductor Technology School of MicroelectronicsXidian University

In this paper, we propose and demonstrate experimentally and numerically a hierarchical timedelay optical reservoir computing(RC) system based on cascaded vertical-cavity surface-emitting lasers(VCSELs) with feedback and multiple injections. The prediction performance characteristics of the hierarchical time-delay RC system based on cascaded VCSELs under different reservoir layers are ***, the prediction performance of the hierarchical time-delay RC system is first improved and saturates as the number of reservoir layers increases. Besides, the impacts of key factors on predicting the hierarchical time-delay RC system are also analyzed in detail experimentally and numerically. This proposed hierarchical time-delay RC system based on VCSELs is useful for the further development of RC systems and may be beneficial to improve the ability of RC systems to solve more complex problems.

关键词： vertical-cavity surface-emitting laser reservoir computing neuromorphic photonics time-delay system information processing

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A new approach to pedestal differentiation for soil loss estimation-a case study from a burnt area in north-central Portugal

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Journal of Forestry Research 2024年第3期35卷 45-54页

作者： Frank G.A.Verheijen Martinho A.S.Martins Sergio A.Prats Jan J.Keizer Centre for Environmental and Marine studies(CESAM) Department Environment and PlanningUniversity of Aveiro3810-193 AveiroPortugal Mediterranean Institute for Agriculture Environment and Development(MED-CHANGE)Institute for Advanced Studies and ResearchUniversity of EvoraPolo da MitraAp.947006-554 EvoraPortugal GeoBiociencias Geotecnologias E Geoengenharias(GEOBIOTEC)Department Environment and PlanningUniversity of Aveiro3810-193 AveiroPortugal

Soil pedestals have long been used as qualitative indicators of soil splash *** rangelands,plant-capped pedestals,generally grass tussocks,have also been used to quantitatively estimate soil loss since the first half of the twentieth *** agricultural lands,forests,and bad-lands,stone-capped pedestals have been used as qualitative and semi-quantitative indicators of active,'extreme'*** work has been reported on using capstone pedestal data for quantifying soil *** postulate that three distinct capstone pedestal types may be present in any given location and that a detailed analysis of a pedestal height histogram may be used to recognize their *** analysis can subsequently inform if soil loss can be reliably estimated and if so,which of the existing methods using pedestal height data will provide more accurate *** three proposed capstone pedestal types are:(1)neo-pedestals formed underneath surface stones exposed by(partial)removal of the soil surface cover;(2)endo-pedestals formed underneath stones that were buried in the soil but have been exposed by erosion;and(3)phoenix-pedestals formed underneath stones from collapsed *** the pedestal height histogram of any given location,a skew to smaller heights may indicate the existence of endo-and/or phoenix-pedestals,which may be revealed as a bi-(or tri)modal distribution when using a smaller bin *** concept was applied to a case study where soil loss had been monitored for control plots and mulched plots during a 5-year period following wildfire in a eucalypt *** measured pedestal heights and used methods to quantitatively assess soil loss from soil pedestal data in the available *** pedestal data at the end of the 5-year period under or overestimated soil loss in the control treatment,with results ranging from 60 to 115%of measured soil loss,depending on the *** is postulated that phoenix-and endo-pedestals may be a driving fact

关键词： Soil pedestals Mulch Wildfire Soil erosion Char

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Short-term prediction for chaotic time series based on photonic reservoir computing using VCSEL with a feedback loop

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Photonics Research 2024年第6期12卷 1222-1230页

作者： XINGXING GUO HANXU ZHOU SHUIYING XIANG QIAN YU YAHUI ZHANG YANAN HAN TAO WANG YUE HAO State Key Laboratory of Integrated Service Networks Xidian UniversityXi'an 710071China State Key discipline Laboratory of Wide Bandgap Semiconductor Technology School of MicroelectronicsXidian UniversityXi'an 710071China

Chaos,occurring in a deterministic system,has permeated various fields such as mathematics,physics,and life ***,the prediction of chaotic time series has received widespread attention and made signifi-cant ***,many problems,such as high computational complexity and difficulty in hardware im-plementation,could not be solved by existing *** overcome the problems,we employ the chaotic system of a vertical-cavity surface-emitting laser(VCSEL)mutual coupling network to generate chaotic time series through optical system simulation and experimentation in this ***,a photonic reservoir com-puting based on VCSEL,along with a feedback loop,is proposed for the short-term prediction of the chaotic time *** relationship between the prediction difficulty of the reservoir computing(RC)system and the differ-ence in complexity of the chaotic time series has been studied with ***,the attention coefficient of injection strength and feedback strength,prediction duration,and other factors on system perfor-mance are considered in both simulation and *** use of the RC system to predict the chaotic time series generated by actual chaotic systems is significant for expanding the practical application scenarios of the RC.

关键词： loop chaotic prediction

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Fine description of unconventional clastic oil reservoirs

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Petroleum Research 2024年第2期9卷 289-303页

作者： Huanqing Chen Research Institute of Petroleum Exploration&development PetroChinaChina

The latest researches reveal that studies on unconventional clastic oil reservoirs in China generally lag far behind those in other countries in respect of content and *** study presents the definition and classification of unconventional oil reservoirs and analyzes the problems in the fine description of unconventional oil *** key content of the fine description of unconventional oil reservoirs is summarized from four aspects:fine fracture characterization based on fine structure interpretation,reservoir architecture characterization based on sedimentary facies,characteristics of nanoscale microscopic pore structure of reservoir,and evaluation of source rock and“sweet spot zone”.Finally,this study suggests that development of fine description of unconventional clastic oil reservoirs in the future should focus on rock brittleness analysis and fracture modeling,geophysical characterization of unconventional clastic oil reservoirs,fluid description of tight reservoirs,and physical/numerical simulation experiments of unconventional oil reservoirs.

关键词： Unconventional clastic reservoir Fine reservoir description Oil sand Tight oilShale oil Fracture characterization Nanoscale microscopic pore structure Sweet spot

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Pockets of Prosperity

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ChinAfrica 2024年第2期16卷 22-23页

作者： WANG JINJIE Research Office of the Institute of South-South Cooperation and development Centre for African studies Peking University

As African countries look to enhance their manufacturing industries and speed up industrialisation,they are learning valuable insights from the development experience of industrial parks worldwide,particularly from Ch... 详细信息

关键词： China. Prosper African

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BMPRⅡ^(+)neural precursor cells isolated and characterized from organotypic neurospheres:an in vitro model of human fetal spinal cord development

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Neural Regeneration Research 2024年第2期19卷 447-457页

作者： Michael W.Weible II Michael D.Lovelace Hamish D.Mundell Tsz Wai Rosita Pang Tailoi Chan-Ling Bosch Institute Discipline of Anatomy and Histology(F13)University of SydneySydneyNSWAustralia School of Environment and Science Griffith UniversityNathanQLDAustralia discipline of Medicine Nepean Clinical SchoolFaculty of Medicine and HealthUniversity of SydneyKingswoodNSWAustralia New South Wales Brain Tissue Resource Centre School of Medical SciencesFaculty of Medicine and HealthUniversity of SydneyCharles Perkins Centre(D17)SydneyNSWAustralia

Roof plate secretion of bone morphogenetic proteins(BMPs)directs the cellular fate of sensory neurons during spinal cord development,including the formation of the ascending sensory columns,though their biology is not well ***-ⅡBMP receptor(BMPRⅡ),the cognate receptor,is expressed by neural precursor cells during embryogenesis;however,an in vitro method of enriching BMPRⅡ^(+)human neural precursor cells(hNPCs)from the fetal spinal cord is *** was undertaken on intact second-trimester human fetal spinal cord using antibodies to BMPRⅡand leukemia inhibitory factor(LIF).Regions of highest BMPRⅡ^(+)immunofluorescence localized to sensory *** and meningeal-associated BMPRⅡ^(+)vascular cells were identified in both intact fetal spinal cord and cortex by co-positivity with vascular lineage markers,CD34/*** immunostaining identified a population of somas concentrated in dorsal and ventral horn interneurons,mirroring the expression of LIF receptor/CD118.A combination of LIF supplementation and high-density culture maintained culture growth beyond 10 passages,while synergistically increasing the proportion of neurospheres with a stratified,*** neurospheres were characterized by BMPRⅡ^(+)/MAP2ab^(+/–)/βⅢ-tubulin^(+)/nestin^(–)/vimentin^(–)/GFAP^(–)/NeuN^(–)surface hNPCs surrounding a heterogeneous core ofβⅢ-tubulin^(+)/nestin^(+)/vimentin^(+)/GFAP^(+)/MAP2ab^(–)/NeuN^(–)multipotent *** cultures from tripotential neurospheres contained neuronal(βⅢ-tubulin^(+)),astrocytic(GFAP+),and oligodendrocytic(O4+)lineage ***-activated cell sorting-sorted BMPRⅡ^(+)hNPCs were MAP2ab^(+/–)/βⅢ-tubulin^(+)/GFAP^(–)/O4^(–)in *** is the first isolation of BMPRⅡ^(+)hNPCs identified and characterized in human fetal spinal *** data show that LIF combines synergistically with high-density reaggregate cultures to support the organotypic reorganization of neurospheres,characterize

关键词： BMPRⅡ bone morphogenetic protein histotypic human spinal cord development leukemia inhibitory factor neurosphere organotypic reaggregate sensory columns

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