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Nano Research 2020年第1期13卷 145-150页

作者： Dogan Kaya richard J.Cobley richard e.palmer Department of electronics and Automation Vocational School of AdanaCukurova University01160CukurovaAdanaTurkey Nanoscale Physics Research Laboratory School of Physics and AstronomyUniversity of BirminghamEdgbastonBirminghamB152TTUK College of engineering Swansea UniversityBay CampusFabian WaySwanseaSA18ENUK

Understanding the atomistic formation of oxide layers on semiconductors is important for thin film fabrication,scaling down conventional devices and for the integration of emerging research ***,the initial oxidation of Si(111)is studied using the scanning tunneling *** to the complete saturation of the silicon surface with oxygen,we are able to probe the atomic nature of the oxide layer *** establish the threshold for local manipulation of inserted oxygen sites to be+3.8 *** by combining imaging with local atomic manipulation are we able to determine whether inserted oxygen exists beneath surface-bonded oxygen sites and differentiate between sites that have one and more than one oxygen atom inserted beneath the *** to the creation of the thin oxide film we observe a flip in the manipulation rates of inserted oxygen sites consistent with more oxygen inserting beneath the silicon surface.

关键词： scanning tunneling microscopy(STM) local manipulation Si(111) oxidation

Neuromorphic nanocluster networks:Critical role of the substrate in nano-link formation

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Nano Research 2023年第7期16卷 10500-10506页

作者： Wenkai Wu Alexey V.Verkhovtsev Theodoros Pavloudis Andrey V.Solov’yov richard e.palmer Nanomaterials Lab Faculty of Science and EngineeringSwansea UniversityBay CampusFabian WaySA18ENSwanseaUK MBN Research Center Altenhöferallee 360438 Frankfurt am MainGermany School of Physics Faculty of SciencesAristotle University of ThessalonikiGR-54124 ThessalonikiGreece

Atomic cluster-based networks represent a promising architecture for the realization of neuromorphic computing systems,which may overcome some of the limitations of the current computing *** formation and breakage of links between the clusters are of utmost importance for the functioning of these computing *** paper reports the results of molecular dynamics simulations of synapse(bridge)formation at elevated temperature and thermal breaking processes between 2.8 nmsized Au1415 clusters deposited on a carbon substrate,a model ***,we find that the bridge formation process is driven by the diffusion of gold atoms along the substrate,no matter how small the gap between the clusters *** complementary simulations of the bridge breaking process reveal the existence of a threshold bias voltage to activate bridge rupture via Joule *** results provide an atomistic-level understanding of the fundamental dynamical processes occurring in neuromorphic cluster arrays.

关键词： atomic-switch network nanoclusters nanoparticles(NPs) clusters on surfaces synapse neuromorphics molecular dynamics(MD)

Angular dependence of nanoparticle generation in the matrix assembly cluster source

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Nano Research 2019年第12期12卷 3069-3074页

作者： Maria Chiara Spadaro Junlei Zhao William D.Terry Jian Liu Feng Yin Flyura Djurabekova richard e.palmer College of engineering Swansea UniversityBay CampusFabian WaySwansea SAI 8ENUK Department of Physics and Helsinki Institute of Physics University of HelsinkiP.O.Box43f FIN-00014HelsinkiFinland Nanoscale Physics Research Laboratory School of Physics and AstronomyUniversity of BirminghamBirmingham B152TTUK National Center for electron Microscopy in Beijing Key Laboratory cf Advanced Materials(MOE)The State Key Laboratory of New Ceramics and Fine ProcessingSchool of Materials Science and EngineeringTsinghua UniversityBeijing 100084China School of Physics and Information Technology Shaanxi Normal UniversityXian 710062China Catalan Institute of Nanoscience and Nanotechnology(ICN2) CSIC and BISTCampus UABBellaterra08193 BarcelonaCataloniaSpain

The matrix assembly cluster source(MACS)represents a bridge between conventional instruments for cluster beam deposition(CBD)and thelevel of industrial *** method is based on Ar^+ion sputtering of a pre-condensed Ar-M matrix(where M,is typically a metal such asAg).each Ar^+ion produces a collision cascade and thus the formation of metal clusters is in the matrix,which are then sputtered *** wepresent an experimental and computational investigation of the cluster emission process,specifically its dependence on the Ar^+ion angle of in cidence and the cluster emission *** find the in cide nee angle strongly in flue nces the emerging cluster flux,which is assigned to thespatial location of the deposited primary ion energy relative to the cluster into the *** also found an approximately constant anglebetween the incident ion beam and the peak in the emitted cluster distribution,with value between 99°and 109°.

关键词： cluster beam deposition scale-up nano particles silver ligand-free green synthesis

Sustainable land management in Mali

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Geography and Sustainability 2024年第3期5卷 382-391页

作者： Karim Nchare Marcel Vitouley richard Mbih Vanderbilt University USA African School of economics Benin Pennsylvania State University USA

This study uses logistic and Poisson regression models to examine the factors influencing the adoption of sustain-able land management(SLM)practices in Mali using two rounds of the nationally representative survey enquête Agricole de Conjoncture Intégrée aux Conditions de Vie des Mé*** SLMs considered include the applica-tion of organic fertilizers,the application of inorganic fertilizers,the use of improved seeds,and the practice of *** average the application of organic fertilizers(39.2%),and inorganic fertilizers(28.7%)are the most frequent SLM practices among Malian farmers,and between 2014 and 2017,we observe a decline in the practice of *** regression results show that farmers’adoption of different SLMs is significantly associated with biophysical factors(average temperature,climate type,plot size,plot shape,and location),de-mographic factors(age,gender,education,household size),and socioeconomic factors(number of cultivated plots,livelihood diversification,type of crop grown,market access,credit access,economic shocks,and social capital).Our findings suggest that policymakers and agricultural development agencies in Mali need to adopt a multidimensional policy framework to unlock the untapped potential of SLM practices in promoting sustainable agriculture and food security.

关键词： Sustainable land management Africa Logistic regression models Poisson regression model

Nearest Neighbor Sampling of Point Sets Using Rays

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1131-1174页

作者： Liangchen Liu Louis Ly Colin B.Macdonald richard Tsai Department of Mathematics The University of Texas at Austin2515 SpeedwayAustinTX 78712USA Oden Institute for Computational engineering and Sciences The University of Texas at Austin201 E24th StAustinTX 78712USA Department of Mathematics University of British Columbia1984 Mathematics RdVancouverBCV6T1Z2Canada

We propose a new framework for the sampling,compression,and analysis of distributions of point sets and other geometric objects embedded in euclidean *** approach involves constructing a tensor called the RaySense sketch,which captures nearest neighbors from the underlying geometry of points along a set of *** explore various operations that can be performed on the RaySense sketch,leading to different properties and potential *** information about the data set can be extracted from the sketch,independent of the ray *** integrals on point sets can be efficiently computed using the *** also present several examples illustrating applications of the proposed strategy in practical scenarios.

关键词： Point clouds Sampling Classification Registration Deep learning Voronoi cell analysis

Wildfire severity alters soil microbial exoenzyme production and fungal abundances in the southern Appalachian Mountains

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Pedosphere 2024年第5期34卷 865-878页

作者： Megan L.SCHILL richard BAIRD Shawn P.BROWN Allison M.VeACH Department of Integrative Biology University of Texas at San Antonio Biochemistry Molecular Biology Entomology and Plant Pathology Department Mississippi State University Department of Biological Sciences The University of Memphis

Climate change has increased drought frequency and duration that are exacerbated by increased temperatures globally. This effect has, and will continue,to increase fire occurrence across many regions of North America. In the southern Appalachian Mountains, wildfires with high burn severity occurred in 2016due to increased drought and human activity. To investigate the effects of burn severity on soil physicochemical properties, microbial extracellular enzyme production, and microbial abundances in a temperate region, surface soils (0–15 cm) were collected from two sites (the Great Smoky Mountains National Park in Tennessee and the Nantahala National Forest in North Carolina, USA) spanning lightly, moderately, and severely burned areas, accompanied by adjacent unburned locations that act as controls. The soil samples were collected at three time points between 2017 and 2019 (i.e., 0.5, 1, and 2.5 years post-fire)among burn severity plots. Total hydrolytic enzyme production varied over time, with severe burn plots having significantly lower enzyme production at 2.5years post-fire. Individual enzymes varied among burn severities and across time post-fire. Light burn plots showed greater carbon-specific (β-glucosidase and β-xylosidase) and phosphorus-specific (acid phosphatase) enzyme activities at 0.5 years post-fire, but this effect was transient. At 2.5 years post-fire, theβ-xylosidase and acid phosphatase activities were lower in severe or moderate burn plots relative to the controls. In contrast, the activity of nitrogen-specific enzyme leucyl aminopeptidase was the lowest in severe burn plots at 0.5 years post-fire, but was the lowest in light burn plots at 2.5 years post-fire. The fungi:bacteria ratio declined with burn severity, indicating that fungi are sensitive or less resilient to high burn severity during recovery. These results suggest that wildfires alter trajectories for soil microbial structure and function within a 2.5-year timeframe, which potentially

关键词： 16S rRNA burn severity extracellular enzyme fungi:bacteria ratio internal transcribed spacer microbial structure

Carbon dioxide enrichment affected flower numbers transiently and increased successful post-pollination development stably but without altering final acorn production in mature pedunculate oak (Quercus robur L.)

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Journal of Forestry Research 2024年第4期35卷 1-12页

作者： Ryan McClory richard H.ellis Martin Lukac Jo Clark Carolina Mayoral Kris M.Hart Andrew R.G.Plackett A.Rob MacKenzie School of Agriculture Policy and DevelopmentUniversity of ReadingAgricultureEarley GateWhiteknights RoadPO Box 237Reading RG66EUUK Faculty of Forestry and Wood Sciences Czech University of Life Sciences PraguePrague 165000Czechia Future Trees Trust Harwell Innovation CentreBuilding 173Curie AvenueHarwellOxford OX110QGUK Birmingham Institute of Forest Research University of BirminghamEdgbastonBirmingham B152TTUK School of Biosciences University of BirminghamEdgbastonBirmingham B152TTUK School of Geography Earth and Environmental SciencesUniversity of BirminghamEdgbastonBirmingham B152TTUK

Acorn production in oak(Quercus spp.)shows considerable inter-annual variation,known as masting,which provides a natural defence against seed predators but a highly-variable supply of acorns for uses such as in commercial tree planting each *** emissions of greenhouse gases have been very widely reported to influence plant growth and seed or fruit size and quantity via the‘fertilisation effect’that leads to enhanced *** examine if acorn production in mature woodland communities will be affected by further increase in CO_(2),the contents of litter traps from a Free Air Carbon enrichment(FACe)experiment in deciduous woodland in central england were analysed for numbers of flowers and acorns of pedunculate oak(Quercus robur L.)at different stages of development and their predation levels under ambient and elevated CO_(2) ***-annual variation in acorn numbers was considerable and cyclical between 2015 and 2021,with the greatest numbers of mature acorns in 2015,2017 and 2020 but almost none in *** numbers of flowers,enlarged cups,immature acorns,empty acorn cups,and galls in the litter traps also varied amongst years;comparatively high numbers of enlarged cups were recorded in 2018,suggesting *** at this site is a fruit maturation masting species(i.e.,the extent of abortion of pollinated flowers during acorn development affects mature acorn numbers greatly).Raising the atmospheric CO_(2) concentration by 150μL L^(−1),from early 2017,increased the numbers of immature acorns,and all acorn evidence(empty cups+immature acorns+mature acorns)detected in the litter traps compared to ambient controls by 2021,but did not consistently affect the numbers of flowers,enlarged cups,empty cups,or mature *** number of flowers in the elevated CO_(2) plots’litter traps was greater in 2018 than 2017,one year after CO_(2) enrichment began,whereas numbers declined in ambient *** with CO_(2) also increased the number o

关键词： Quercus robur L. Acorns Masting Pedunculate oak Carbon dioxide

Genomic variation,environmental adaptation,and feralization in ramie,an ancient fiber crop

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Plant Communications 2024年第8期5卷 189-207页

作者： Zeng-Yuan Wu Mark A.Chapman Jie Liu richard I.Milne Ying Zhao Ya-Huang Luo Guang-Fu Zhu Marc W.Cadotte Ming-Bao Luan Peng-Zhen Fan Alex K.Monro Zhi-Peng Li richard T.Corlett De-Zhu Li Germplasm Bank of Wild Species&Yunnan Key Laboratory of Crop Wild Relatives Omics Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China School of Biological Sciences University of SouthamptonSouthampton SO171BJUK CAS Key Laboratory for Plant Diversity and Biogeography of east Asia Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China Institute of Molecular Plant Sciences School of Biological SciencesUniversity of EdinburghEdinburgh EH93JHUK Department of Biological Sciences University of Toronto-ScarboroughTorontoOntarioCanada Institute of Bast Fiber Crops Chinese Academy of Agricultural SciencesChangshaHunan 410205China Royal Botanic Gardens Kew RichmondSurrey TW93AEUK Center for Integrative Conservation and Yunnan Key Laboratory for the Conservation of Tropical Rainforests and Asian elephants Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglunYunnan 666303China

Feralization is an important evolutionary process,but the mechanisms behind it remain poorly ***,we use the ancient fiber crop ramie(Boehmeria nivea(L.)Gaudich.)as a model to investigate genomic changes associated with both domestication and *** first produced a chromosome-scale de novo genome assembly of feral ramie and investigated structural variations between feral and domesticated ramie ***,we gathered 915 accessions from 23 countries,comprising cultivars,major landraces,feral populations,and the wild *** on whole-genome resequencing of these accessions,we constructed the most comprehensive ramie genomic variation map to ***,demographic,and admixture signal detection analyses indicated that feral ramie is of exoferal or exo-endo origin,i.e.,descended from hybridization between domesticated ramie and the wild progenitor or ancient *** ramie has higher genetic diversity than wild or domesticated ramie,and genomic regions affected by natural selection during feralization differ from those under selection during *** analyses showed that feral and domesticated ramie have similar ecological niches that differ substantially from the niche of the wild progenitor,and three environmental variables are associated with habitat-specific adaptation in feral *** findings advance our understanding of feralization,providing a scientific basis for the excavation of new crop germplasm resources and offering novel insights into the evolution of feralization in nature.

关键词： ramie fiber offering

Contribution of CT Scanning in the Investigation of Cranioencephalic Lesions in Bangui

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Open Journal of Radiology 2024年第3期14卷 156-165页

作者： Bangue Songrou Francky Kouandongui Timothée Mobima Borel Tambala Yannick Héritier Sombot-Soule Stéphane Kouzou Judith Guiaba Kette euloge Tapiade Bidan richard Bazogo National Center of Medical Imaging of Bangui Bangui Central African Republic Maman elisabeth DOMITIeN Hospital Bangui Central African Republic Community Hospital of Bangui Bangui Central African Republic

Introduction: Cranioencephalic exploration has always played a major role in CT scans. In the Central Africa Republic (CAR), the lack of cross-sectional imaging before the year 2020 meant that no study had focused on cranioencephalic lesions. The aim of this study was to contribute to improving the management of cranioencephalic pathologies in CAR. Patients and Method: The study took place at the Bangui National Medical Imaging Centre (CNIMB). It was a retrospective study over a two-year period (March 1, 2021 to February 30, 2023). All patients referred for cranioencephalic CT scans were included, regardless of age or sex. Results: 1745 CT scans were performed, 575 of which were cranioencephalic CT scans. The majority of patients were male (53%). Most lived in the capital Bangui (90.9%). Patients aged 61 and over were the most representative. The distribution of patients by requesting department showed that the reception and emergency department was one of the least requesting departments. The main abnormalities observed were strokes, 82.1% of which were ischaemic strokes and 17.9% haemorrhagic strokes. Strokes were followed by degenerative lesions. Post-traumatic injuries included haemorrhagic contusions (38.3%), subdural haematomas in 20.5% of cases, and extradural haematomas (9.3%). Craniofacial lesions (fractures) were observed in 45.8% of cases. Conclusion: Cranioencephalic scans accounted for 1/3 of CT examinations performed during the study period. It revealed pathologies that could not be detected by conventional means. All in all, CT scans contributed to the diagnosis of cerebral pathologies.

关键词： Cranioencephalic Scan National Medical Imaging Centre Bangui

Contribution of CT in the exploration of Non-Traumatic Pathologies of the Lumbar Spine in Adults in Bangui

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Open Journal of Radiology 2024年第3期14卷 125-134页

作者： Bangue Songrou Francky Kouandongui Timothée Mobima Yannick Héritier Sombot Borel Tambala Stéphane Kouzou Judith Guiaba Kette euloge Tapiade Bidan richard Bazogo National Center of Medical Imaging of Bangui Bangui Central Africa Republic Maman elisabeth DOMITIeN Hospital Bangui Central Africa Republic Community Hospital of Bangui Bangui Central Africa Republic

Background: In Central African Republic, a study carried out in 2019 highlighted the limits of conventional radiography in the diagnosis of non-traumatic lower back pain in adults. Objective: The objective of this study is to show the value of CT scanning in the exploration of non-traumatic pathologies of the lumbar spine in adults. Patients and Method: Retrospective and descriptive cross-sectional study covering the files of patients aged at least 18 years old, sent for lumbar scanning from March 1 to December 31, 2021 at the medical imaging center. Results: In total, 593 scan examinations were performed including 159 (26.8%) examinations of the lumbar spine. The average age of the patients was 49.84 years. The majority were male (66%). 127 (79.8%) were referred mainly to the neurology and rheumatology departments. Common low back pain (n = 97, 61%) was the main reason for requesting a CT scan. The lumbar scan was performed without contrast product in 88.7% of cases. In total, 148 (93.1%) examinations were pathological and dominated by overall disc overhang (62.2%) and somatic and interapophyseal osteoarthritis (16.9%). The other lesions were spondylodiscitis (7.4%), tumor-like lesions (3.4%) and narrow lumbar canal (1.4%).

关键词： CT Scanning Lumbar Bangui Adults