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内蒙古草原优势物种光合速率对极端干旱的响应

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Journal of Plant Ecology 2024年第3期17卷 5-15页

作者： Yalong Shi Yuanbo Cao Honghui Wu Chong Xu Qiang Yu Xiaoan Zuo Xingguo Han melinda d.smith Alan K.Knapp Chengjie Wang Guodong Han State Key Laboratory of Effcient Utilization of Arid and Semi-arid Arable Land in Northern China Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China Key Laboratory of Arable Land Quality Monitoring and Evaluation Ministry of Agriculture and Rural AffairsInstitute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China China Rida Investment and development Group Corp Ltd Beijing 100040China School of Grassland Science Beijing Forestry UniversityBeijing 100083China Urat desert-grassland Research Station Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China department of Biology and Graduate degree Program in Ecology Colorado State UniversityFort CollinsCO 80523USA College of Grassland Resource and EnvironmentalInner Mongolia Agricultural UniversityHohhot 010011China

评估极端干旱对优势植物物种光合速率(Pn)的影响对于我们理解极端干旱影响生态系统功能的机制至关重要。极端干旱可能由降雨量减少或降雨频率减少造成。这两种不同模式的极端干旱可能造成不同的影响。此外,不同草原类型可能对这两种极... 详细信息

评估极端干旱对优势植物物种光合速率(Pn)的影响对于我们理解极端干旱影响生态系统功能的机制至关重要。极端干旱可能由降雨量减少或降雨频率减少造成。这两种不同模式的极端干旱可能造成不同的影响。此外,不同草原类型可能对这两种极端干旱模式表现出不同的敏感性。然而,目前尚不清楚这两种极端干旱模式对草原优势植物物种Pn的影响有何差异,以及在不同草原类型这两种不同模式的极端干旱的效应是否改变。为此,我们于2014年在内蒙古草原两个不同类型的草原(荒漠草原vs.典型草原)站点各进行了一项多年的极端干旱(CHR:将生长季期间每次降雨事件的降雨量减少66%***:完全排除生长季内一段较短时间的降水)模拟实验。于2017年的7月和8月,我们在这两个草原站点各测量了两种优势物种的Pn。结果发现,CHR和INT均显著降低了优势物种的Pn。无论草原类型如何,INT对Pn造成的负面影响都更大。在荒漠草原,极端干旱对Pn的负面影响普遍大于典型草原,尤其是对于CHR处理下的羊草(Leymus chinensis)。这些结果表明,与降雨量减少相比,降雨频率减少所引起的极端干旱对Pn的负面影响更大。草地类型可能会改变极端干旱模式效应的程度,但不会改变其方向。这些发现强调了应对未来极端干旱的草原生态系统管理应考虑极端干旱模式和草地类型的影响。

关键词：极端气候荒漠草原典型草原极端干旱模式季节性干旱

Genotypic diversity of a dominant C_(4) grass across a long-term fire frequency gradient

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Journal of Plant Ecology 2013年第6期6卷 448-458页

作者： Cynthia C.Chang melinda d.smith department of Ecology and Evolutionary Biology Yale UniversityNew HavenCT 06511USA department of Biology University of WashingtonSeattleWA 98195USA department of Biology Colorado State UniversityFort CollinsCO 80523USA

Aims and Methods diversity-disturbance research has focused on community diversity,but disturbance frequency could impact diversity within species as well,with important consequences for community diversity and ecosystem *** examined patterns of genetic diversity of a dominant grass species,Andropogon gerardii,in native North American tallgrass prairie sites located in eastern Kansas that have been subjected to a gradient of fire frequency treatments(burned every 1,2,4 or 20 years)since the *** addition,we were able to assess the relationships between genetic diversity of ***,species diversity and productivity across this range of fire *** Findings We found no significant relationships between genetic diversity of *** at the local scale(1 m^(2) plot level)and disturbance frequency(burned 2 to 32 times over a 38-year period).However,at the site level(*** all plots sampled within a site,~100 m^(2))there were differences in genotype richness and composition,as well as genomic dissimilarity among individuals of *** richness was greatest for the site burned at an intermediate(4-year)frequency and lowest for the infrequently(20-year)burned *** addition,genotypes found in the frequently burned sites were more similar from each other than expected by random chance than those found in the infrequently burned *** composition of *** was not significantly different between the frequently burned sites(annual vs.2 year)but did differ between frequently burned and infrequently burned sites(1 and 2 year vs.4 and 20 year,etc.).Together,these results suggest site-level ecological sorting of genotypes in intact prairie across a broad gradient of disturbance frequencies,likely driven by alterations in environmental *** fire promotes the abundance of dominant grass species,reduces plant community diversity and impacts ecosystem processes such as *** study suggests that

关键词： Andropogon gerardii disturbance frequency genetic relatedness genetic-species diversity relationship genotype richness intermediate disturbance hypothesis productivity tallgrass prairie

Long-term effects of fire frequency and season on herbaceous vegetation in savannas of the Kruger National Park,South Africa

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Journal of Plant Ecology 2013年第1期6卷 71-83页

作者： melinda d.smith Brian Wvan Wilgen Catherine E.Burns Navashni Govender Andre L.F.Potgieter Sandy Andelman Harry C.Biggs Judith Botha Winston S.W.Trollope department of Ecology and Evolutionary Biology Yale UniversityPO Box 208106New HavenCT 06520USA Centre for Invasion Biology Council for Scientific and Industrial Research Natural Resources and the EnvironmentPO Box 320Stellenbosch 7600South Africa North Carolina Chapter Office The Nature Conservancy4705 University DriveSuite 290DurhamNC 27707USA Scientific Services South African National ParksPrivate Bag X402Skukuza 1350South Africa Tropical Ecology Assessment and Monitoring(TEAM)NetworkConservation International2011 Crystal DriveSuite 500ArlingtonVA 22202USA department of Livestock and Pasture Science University of Fort HarePrivate Bag X1314Alice 5700South Africa

Aims:The long-term effects of changing fire regimes on the herbaceous component of savannas are poorly understood but essential for understanding savanna *** present results from one of the longest running(>44 years)fire experiments in savannas,the experimental burn plots(EBPs),which is located in the Kruger National Park(South Africa)and encompasses four major savanna vegetation types that span broad spatial gradients of rainfall(450–700 mm)and soil ***:Herbaceous vegetation was sampled twice in the EBPs using a modified step-point method,once prior to initiation of the experiment(1954)and again after 44–47 *** combinations of three fire frequency(1-,2-and 3-year return intervals)and five season(before the first spring rains,after the first spring rains,mid-summer,late summer and autumn)treatments,as well as a fire exclusion treatment,were applied at the plot level(;7 ha each),with each treatment(n=12 total)replicated four times at each of the four sites(n=192 plots total).The effects of long-term alterations to the fire regime on grass community structure and composition were analyzed separately for each *** Findings:Over the 44+years duration of the experiment,fires were consistently more intense on sites with higher mean annual rainfall(>570 mm),whereas fires were not as intense or consistent for sites with lower and more variable rainfall(d potentially higher herbivory due to greater soil *** the plots were open to grazing,the impacts of herbivory along with more variable rainfall regimes likely minimized the effects of fire for the more arid *** a consequence,fire effects on grass community structure and composition were most marked for the higher rainfall sites and generally not significant for the more arid *** the high-rainfall sites,frequent dry season fires(1-to 3-year return intervals)resulted in high grass richness,evenness and diversity,whereas fire exclusion and growing se

关键词： climate fire intensity grass herbivory soil fertility

食草昆虫通过增加植物群落中优势物种的占比来缓解极端干旱对整个植物群落的负面影响

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Journal of Plant Ecology 2021年第6期14卷 1030-1036页

作者： Chong Xu Yuguang Ke Honghui Wu melinda d.smith Nathan P.Lemoine Weiguo Zhang Qiang Yu State Key Laboratory of Grassland Agro-ecosystems College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhou 730020China National Hulunber Grassland Ecosystem Observation and Research Station Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China department of Biology Colorado State UniversityFort CollinsCO 80523USA department of Biological Sciences Marquette UniversityMilwaukeeWI 53233USA

极端干旱和食草昆虫均会抑制草原生态系统中植物的生长。食草昆虫也可能会调控植物群落对极端干旱的响应。但是关于二者交互作用对植物群落的影响鲜有报道。通过在内蒙古半干旱草原设置的极端干旱与食草昆虫交互控制实验,本研究探究了... 详细信息

极端干旱和食草昆虫均会抑制草原生态系统中植物的生长。食草昆虫也可能会调控植物群落对极端干旱的响应。但是关于二者交互作用对植物群落的影响鲜有报道。通过在内蒙古半干旱草原设置的极端干旱与食草昆虫交互控制实验,本研究探究了二者交互作用对植物群落的影响。研究结果表明,干旱和食草昆虫的单独作用均降低了植物群落的总盖度。但在二者交互作用下,食草昆虫通过增加植物群落中耐旱优势物种的相对盖度降低了干旱对总盖度的负面影响。我们的结果证明了食草昆虫可以缓解极端干旱对植物群落的负面影响。

关键词：极端干旱食草昆虫植物群落盖度半干旱草原优势物种

A new view of the local Universe

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 167-168页

作者： Lister Staveley-smith International Centre for Radio Astronomy Research(ICRAR) University of Western AustraliaCrawley WA 6009Australia ARC Centre of Excellence for All Sky Astrophysics(ASTRO 3d) Crawley WA 6009Australia

The distribution and kinematics of gas in and around dark matter halos, the formation of stellar populations from the gravitational collapse of gas clouds, and the interaction of stars and their remnants with interste... 详细信息

关键词： galaxies stars galactic

Competitive interactions and coexistence of sympatric flagship carnivores in Asia

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Integrative Zoology 2024年第2期19卷 183-199页

作者： Zhilin LI Jiayu LU Xiaoyi SHI Li’an dUO James L.d.smith Tianming WANG Tianjin Key Laboratory of Conservation and Utilization of Animal diversity College of Life SciencesTianjin Normal UniversityTianjinChina department of Fisheries Wildlife and Conservation BiologyUniversity of MinnesotaSt.PaulMinnesotaUSA Ministry of Education Key Laboratory for Biodiversity Science and Engineering College of Life SciencesBeijing Normal UniversityBeijingChina National Forestry and Grassland Administration Key Laboratory for Conservation Ecology of Northeast Tiger and Leopard BeijingChina

Understanding the competition and coexistence of flagship carnivores is key to creating strategies for their conservation in the face of global carnivore *** studies exploring the dynamics and competition between tigers(Panthera tigris)and leopards(***)span decades,there is a lack of understanding regarding the factors that influence their coexistence mechanisms on a broad scale,as well as the drivers determining their exploitative and interference *** gathered a comprehensive list of research papers among which 36 papers explored the interspecific interactions between tigers and leopards and tested the influence of biotic and abiotic factors on the coexistence mechanisms along three dimensions using multiple response variables regression models;we also tested the influence of ecological drivers determining the exploitative or interference competition between tigers and *** and ungulate density were the most important predictors in regulating the coexistence *** and leopards exhibited more positive relations/higher overlaps as elevation increased in the spatial *** addition,they showed a higher dietary overlap in the prey-rich *** determined that interference competition between tigers and leopards was less frequently observed in habitats with dense tree cover and homogeneous vegetation ***,studies with multiple metrics would promote the detection of interference *** study provides new insight into the competitive interactions and coexistence mechanisms of tigers and leopards on a broad ***-makers and managers should pay more attention to the factors of elevation,prey abundance,and habitat structures for the conservation of tigers and leopards.

关键词： carnivores coexistence mechanisms competitive interactions exploitative competition interference competition

Facile synthesis of intra-nanogap enhanced Raman tags with different shapes

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Nano Research 2024年第9期17卷 8415-8423页

作者： Sanjun Fan Brian T.Scarpitti Zhewen Luo Abigail E.smith Jian Ye Zachary d.Schultz department of Chemistry and Biochemistry The Ohio State UniversityColumbusOhio 43210USA School of Biomedical Engineering Shanghai Jiao Tong UniversityShanghai 200030China

Hot spot engineering in plasmonic nanostructures plays a significant role in surface-enhanced Raman scattering(SERS)for bioanalysis and cell ***,creating stable,reproducible,and strong SERS signals remains challenging due to the potential interference from surrounding chemicals and locating SERS-active analytes into hot-spot ***,we developed a straightforward approach to synthesize intra-gap nanoparticles encapsulating 4-nitrobenzenethiol(4-NBT)as a reporter molecule within these gaps to avoid outside *** made three kinds of intra-gap nanoparticles using nanorods,bipyramids,and nanospheres as cores,in which the nanorods based intra-gap nanoparticles exhibit the highest SERS *** advantage of our method is the ease of preparation of high-yield and stable intra-gap nanoparticles characterized by a short incubation time(10 min)with 4-NBT and quick synthesis without requiring an additional step to centrifuge for the purification of core *** intense localized field in the synthesized hot spots of these plasmonic gap nanostructures holds great promise as a SERS substrate for a broad range of quantitative optical applications.

关键词： hot spot engineering surface enhanced Raman scattering intra-gap nanoparticles 4-nitrobenzenethiol

Aerosol jet printing of surface acoustic wave microfluidic devices

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Microsystems & Nanoengineering 2024年第1期10卷 231-242页

作者： Joseph Rich Brian Cole Teng Li Brandon Lu Hanyu Fu Brittany N.smith Jianping Xia Shujie Yang Ruoyu Zhong James L.doherty Kanji Kaneko Hiroaki Suzuki Zhenhua Tian Aaron d.Franklin Tony Jun Huang department of Biomedical Engineering Duke UniversityDurhamNC 27708USA department of Electrical and Computer Engineering Duke UniversityDurhamNC 27708USA department of Mechanical Engineering Virginia Polytechnic Institute and State UniversityBlacksburgVA 24061USA Thomas Lord department of Mechanical Engineering and Materials Science Duke UniversityDurhamNC 27708USA deptartment of Precision Mechanics Faculty of Science and EngineeringChuo UniversityTokyo 112-8551Japan department of Chemistry Duke UniversityDurhamNC 27708USA

The addition of surface acoustic wave(SAW)technologies to microfluidics has greatly advanced lab-on-a-chip applications due to their unique and powerful attributes,including high-precision manipulation,versatility,integrability,biocompatibility,contactless nature,and rapid ***,the development of SAW microfluidic devices is limited by complex and time-consuming micro/nanofabrication techniques and access to cleanroom facilities for multistep photolithography and vacuum-based *** simplify the fabrication of SAW microfluidic devices with customizable dimensions and functions,we utilized the additive manufacturing technique of aerosol jet *** successfully fabricated customized SAW microfluidic devices of varying materials,including silver nanowires,graphene,and poly(3,4-ethylenedioxythiophene)polystyrene sulfonate(PEdOT:PSS).To characterize and compare the acoustic actuation performance of these aerosol jet printed SAW microfluidic devices with their cleanroom-fabricated counterparts,the wave displacements and resonant frequencies of the different fabricated devices were directly measured through scanning laser doppler ***,to exhibit the capability of the aerosol jet printed devices for lab-on-a-chip applications,we successfully conducted acoustic streaming and particle concentration ***,we demonstrated a novel solution-based,direct-write,single-step,cleanroom-free additive manufacturing technique to rapidly develop SAW microfluidic devices that shows viability for applications in the fields of biology,chemistry,engineering,and medicine.

关键词： printing wave fluid

detailed characterization of kHz-rate laser-driven fusion at a thin liquid sheet with a neutron detection suite

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High Power Laser Science and Engineering 2024年第1期12卷 13-23页

作者： Benjamin M.Knight Connor M.Gautam Colton R.Stoner Bryan V.Egner Joseph R.smith Chris M.Orban Juan J.Manfredi Kyle d.Frische Michael L.dexter Enam A.Chowdhury Anil K.Patnaik department of Engineering Physics Air Force Institute of TechnologyWPAFBOHUSA Physics department Marietta CollegeMariettaOHUSA department of Physics The Ohio State UniversityColumbusOHUSA department of Materials Science and Engineering and Department of Electrical and Computer ScienceThe Ohio State UniversityColumbusOHUSA Intense Energy Solutions LLCPlain CityOHUSA

We present detailed characterization of laser-driven fusion and neutron production(-10^(5)/second) using 8 mJ, 40 fs laser pulses on a thin(<1 μm) d_2O liquid sheet employing a measurement suite. At relativistic inte... 详细信息

We present detailed characterization of laser-driven fusion and neutron production(-10^(5)/second) using 8 mJ, 40 fs laser pulses on a thin(d_2O liquid sheet employing a measurement suite. At relativistic intensity(~ 5 × 10^(18)W/cm^(2))and high repetition rate(1 kHz), the system produces deuterium±deuterium(d-d) fusion, allowing for consistent neutron generation. Evidence of d-d fusion neutron production is verified by a measurement suite with three independent detection systems: an EJ-309 organic scintillator with pulse-shape discrimination, a ~3He proportional counter and a set of 36 bubble detectors. Time-of-flight analysis of the scintillator data shows the energy of the produced neutrons to be consistent with 2.45 MeV. Particle-in-cell simulations using the WarpX code support significant neutron production from d-d fusion events in the laser±target interaction region. This high-repetition-rate laser-driven neutron source could provide a low-cost, on-demand test bed for radiation hardening and imaging applications.

关键词： high-repetition-rate laser-driven fusion laser-plasma interaction liquid target neutron detectors