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Multi-scale drivers of soil resistance predict vulnerability of seasonally wet meadows to trampling by pack stock animals in the Sierra Nevada,USA

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Ecological Processes 2020年第1期9卷 364-377页

作者： Joy S.Baccei Mitchel P.Mcclaran Tim J.Kuhn Stephen c.hart Environmental Systems Graduate Group University of CaliforniaMercedCA 95343USA Uc Merced Vernal Pools and Grassland Reserve UC Merced Natural Reserve SystemMercedCA 95343USA School of Natural Resources and the Environment University of ArizonaTucsonAZ 85721USA Resources Management and Science Yosemite National ParkEl PortalCA 95318USA Department of Life&Environmental Sciences and Sierra Nevada Research Institute University of CaliforniaMercedCA 95343USA.

Background:Meadow ecosystems have important ecological functions and support socioeconomic services,yet are subject to multiple stressors that can lead to rapid *** the Sierra Nevada of the western USA,recreational pack stock(horses and mules)use in seasonally wet mountain meadows may lead to soil trampling and meadow degradation,especially when soil water content is high and vegetation is ***:In order to improve the ability to predict meadow vulnerability to soil disturbance from pack stock use,we measured soil resistance(SR),which is an index of vulnerability to trampling disturbance,at two spatial scales using a stratified-random sampling *** then compared SR to several soil and vegetation explanatory variables that were also measured at the two spatial scales:plant community type(local scale)and topographic gradient class(meadow scale).Results:We found that local-scale differences in drivers of SR were contingent on the meadow scale,which is important because multiple spatial scale evaluation of ecological metrics provides a broader understanding of the potential controls on ecological processes than assessments conducted at a single spatial *** also found two contrasting explanatory models for drivers of SR at the local scale:(1)soil gravimetric water content effects on soil disaggregation and(2)soil bulk density and root mass influence on soil *** resistance was insufficient to sustain pack stock use without incurring soil deformation in wet plant communities,even when plant cover was maximal during a major ***:Our study provides new information on seasonally wet meadow vulnerability to trampling by pack stock animals using multi-scale drivers of SR,including the contrasting roles of soil disaggregation,friction,and *** work aims to inform meadow management efforts in the Sierra Nevada and herbaceous ecosystems in similar regions that are subject to seasonal soil saturation and livestock u

关键词： Hydrogeomorphic classification Hydrologic regime Pack stock Plant communities Soil properties Soil strength

Rapid Identification of Rice Samples Using an Electronic Nose

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Journal of Bionic Engineering 2009年第3期6卷 290-297页

作者： John westbrook W.c.Hoffmann R.E.Lacey USDA-ARS College Station Department of Biological and Agricultural Engineering Texas A&M UniversityCollege Station

Four rice samples of long grain type were tested using an electronic nose (cyranose-320).Samples of 5 g of each variety of rice were placed individually in vials and were analyzed with the electronic nose unit consisting of 32 polymer *** cyranose-320 was able to differentiate between varieties of *** chemical composition of the rice odors for differentiating rice samples needs to be *** optimum parameter settings should be considered during the cyranose-320 training process especially for multiple samples,which are helpful for obtaining an accurate training model to improve identification ***,it is necessary to investigate the E-nose sensor selection for obtaining better classification accuracy.A re- duced number of sensors could potentially shorten the data processing time,and could be used to establish an application pro- cedure and reduce the cost for a specific electronic *** research is needed for developing analytical procedures that adapt the cyranose-320 as a tool for testing rice quality.

关键词： rice grain identification electronic nose data analysis pattern recognition

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海洋环境安全:一种可持续发展的观点

厦门大学学报（自然科学版） 2004年第B8期43卷 254-257页

作者：张珞平洪华生陈伟琪刘泓 William c.hart 厦门大学海洋环境科学教育部重点实验室环境科学研究中心福建厦门361005 福建农业与林业大学资源与环境学院福建福州361005 加拿大Dalhousie大学水资源研究中心 NSB3J2X4Canada

联合国海洋环境保护科学问题联合专家组(GESAMP)是一个由八个联合国机构发起的科学顾问团体,它的报告和述评是各个联合国组织制定有关海洋政策和决策的基础.尽管GESAMP的观点近年来有很大进展,但在如何促进和改善保护海洋环境的行动等... 详细信息

联合国海洋环境保护科学问题联合专家组(GESAMP)是一个由八个联合国机构发起的科学顾问团体,它的报告和述评是各个联合国组织制定有关海洋政策和决策的基础.尽管GESAMP的观点近年来有很大进展,但在如何促进和改善保护海洋环境的行动等问题仍有它的局限性.本文提出了"海洋环境安全"的概念,以促进海洋环境保护和海洋资源的可持续利用,并讨论了海洋环境研究和海洋环境管理应采取的行动.

关键词：海洋环境安全可持续发展海洋污染海洋环境保护持续性原则海洋资源

Altered O-GlcNAcylation and mitochondrial dysfunction,a molecular link between brain glucose dysregulation and sporadic Alzheimer's disease

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Neural Regeneration Research 2023年第4期18卷 779-783页

作者： chia-Wei Huang Nicholas c.Rust Hsueh-Fu Wu Gerald W.hart complex carbohydrate Research center University of GeorgiaAthensGAUSA Department of Biochemistry and Molecular Biology University of GeorgiaAthensGAUSA center for Molecular Medicine University of GeorgiaAthensGAUSA

Alzheimer’s disease is a neurodegenerative disease that affected over 6.5 million people in the United States in 2021,with this number expected to double in the next 40 years without any sort of *** to its heterogeneity and complexity,the etiology of Alzheimer’s disease,especially sporadic Alzheimer’s disease,remains largely *** evidence suggests that brain glucose hypometabolism,preceding Alzheimer’s disease hallmarks,is involved in the pathogenesis of Alzheimer’s ***,we discuss the potential causes of reduced glucose uptake and the mechanisms underlying glucose hypometabolism and Alzheimer’s disease ***,decreased O-Glc NAcylation levels by glucose deficiency alter mitochondrial functions and together contribute to Alzheimer’s disease *** major problem with Alzheimer’s disease research is that the disease progresses for several years before the onset of any symptoms,suggesting the critical need for appropriate models to study the molecular changes in the early phase of Alzheimer’s disease ***,this review also discusses current available sporadic Alzheimer’s disease models induced by metabolic abnormalities and provides novel directions for establishing a human neuronal sporadic Alzheimer’s disease model that better represents human sporadic Alzheimer’s disease as a metabolic disease.

关键词： Alzheimer’s disease amyloid beta brain glucose deficiency glucose uptake hypometabolism mitochondrial dysfunction neurodegenerative disease neurons O-GlcNAc Tau

Disturbance history,species diversity,and structural complexity of a temperate deciduous forest

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Journal of Forestry Research 2020年第2期31卷 397-414页

作者： Jonathan D.Goode carson R.Barefoot Justin L.hart Daniel c.Dey Department of Geography University of AlabamaTuscaloosaAL 35487USA Northern Research Station USDA Forest ServiceColumbiaMO 65211USA

Stand structural complexity enhancement is an increasingly popular management objective,especially on public *** stand structures are hypothesized to support a relatively high degree of native forest diversity and be more resistant and resilient to *** structures are characterized by the presence of deadwood and heterogeneity of tree-size classes and tree *** little is known about how discrete disturbance events affect structural complexity and compositional diversity in Quercus-dominated stands at fine spatial scales(***).We established 200.05 ha fixed-radius plots on the Sipsey Wilderness of William *** National Forest in northern Alabama to quantify woody plant species composition and *** were mapped on each plot to quantify overstory structural complexity and compositional *** extracted two cores from all canopy Quercus spp.c 5 cm diameter at breast height to quantify age,recruitment pulses,and reconstruct canopy disturbance *** species diversity in the sampled area was 1.75 for trees,2.08 for saplings,and 1.69 for *** alba had the greatest basal area,and Ostrya virginiana had the highest *** stand exhibited a reverse J-shaped distribution with a q-factor of *** oldest Quercus dated to 1795,and the largest recruitment pulse occurred in the *** mean return interval for intermediateseverity disturbance was 38 *** we documented no relationships between disturbance frequency and compositional diversity at the neighborhood scale(0.05 ha),less frequent disturbance was associated with higher structural complexity(r^2=0.258,p=0.026)at the neighborhood *** suggest that localized disturbance increases species diversity and structural complexity,but these processes are manifest at the stand level and not at the neighborhood *** conclude that the spatial variability(***,shape,orientation,microsite conditions)is likel

关键词： canopy gap Quercus(oak) Stand development Succession

Three-dimensional light structure of an upland Quercus stand post-tornado disturbance

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Journal of Forestry Research 2020年第1期31卷 141-153页

作者： Kevin G.Willson Lauren E.cox Justin L.hart Daniel c.Dey Department of Geography University of AlabamaTuscaloosaAL 35487USA Department of Environmental Science Policyand ManagementUniversity of CaliforniaBerkeleyCA 94720USA Northern Research Station USDA Forest ServiceColumbiaMO 65211USA

Light is the most common limiting factor in forest plant communities,influencing species composition,stand structure,and stand productivity in closed canopy *** vertical light structure is relatively simple under a closed canopy because most light is captured by overstory ***,wind disturbance events create canopy openings from local to landscape scales that increase understory light intensity and vertical light structural *** studied the effects of an EF-1 tornado on horizontal and vertical(***-dimensional)light structure within a Quercus stand to determine how light structure changed with increasing disturbance *** used a two-tiered method to collect photosynthetic photon flux density at 4.67 m and 1.37 m above the forest floor to construct three-dimensional light structure across a canopy disturbance severity gradient to see if light intensity varied with increasing tornado *** indicate that increased canopy disturbance closer to the tornado track increased light penetration and light structure heterogeneity at lower forest *** light intensity correlated with increased sapling density that was more randomly distributed across the plot and had shifted light capture higher in the stand *** penetration through the overstory was most strongly correlated with decreased stem density in the two most important tree species(based on relative dominance and relative density)in the stand,Quercus alba L.(r=-0.31)and Ostrya virginiana(Mill.)***(r=-0.27,pcated that understory light penetration was most affected by these two *** managers are increasingly interested in patterning silvicultural entries on natural disturbances,they must understand residual stand and light structures that occur after natural disturbance *** providing spatial light data that quantifies light structure post-disturbance,managers can use these results to improve planning required for long-term man

关键词： Photosynthetic photon flux density Midstory Blowdown Heterogeneity

Macro-and microcirculation patterns of intrahepatic blood flow changes in patients with hereditary hemorrhagic telangiectasia

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World Journal of Gastroenterology 2017年第3期23卷 486-495页

作者： Roland c Schelker Ana P Barreiros christina hart Wolfgang Herr Ernst-Michael Jung Department of Internal Medicine III Hematology and OncologyUniversity Hospital of Regensburg93051 RegensburgGermany Ernst-Michael Jung Department of RadiologyUniversity Hospital of Regensburg93051 RegensburgGermany

AIM To evaluated vascular dynamic processes in the liver of hereditary hemorrhagic telangiectasia(HHT) patients by ultrasound(US) considering quantitative analytic methods. METHODS The imaging features on US and contrast-enhanced ultrasound(cEUS) in 18 patients diagnosed with HHT were retrospectively analyzed. Regarding cEUS, realtime contrast harmonic imaging and sulfur hexafluoridefilled microbubbles were used. RESULTS HVa Ms were identified in all 18 patients. By US, the two major caselitz criteria could be detected in 55.6% patients. "color spots" were detected in 72.2% of the cases. Respecting sonographic grading criteria by Buscarini, grade 3 could be demonstrated most frequent(40%). By cEUS, all the patients showed quick and early hyperenhancement during the arterial phase. Significant lowest time to peak(TTP) and highest area under the curve(AUc) values were identified in the hepatic artery(TTP: 69.8%; AUc: 100%) and highest TTP and lowest AUc in the hepatic parenchyma and the portal vein. cONcLUSION For the first time we analyzed cEUS findings of a group of HHT patients regarding macro- and microcirculation. Our data demonstrate significant differences in TTP and AUc values in the four selected regions: hepatic artery, shunt region, portal vein and hepatic parenchyma.

关键词： Hereditary hemorrhagic telangiectasia Intrahepatic shunts contrast-enhanced ultrasound Time-intensity-curve

TDRSS星载导航系统(TONS)的星上构型和算法

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控制工程（北京） 2000年第2期 46-57,45页

作者： cheryl J.Gramling Roger c.hart 何英姿

NASA戈达德空间飞行中心(GSFc)目前正在研制跟踪与数据中继卫星系统(TDRSS)的星上导航系统(TONS),旨在为TDRSS及其后继星TDRSS-Ⅱ的用户提供星上高精度自主导航信息.在探测器平台/远紫外探测器(EP/EUVE)任务上已经进行了一次TONS试验。E... 详细信息

NASA戈达德空间飞行中心(GSFc)目前正在研制跟踪与数据中继卫星系统(TDRSS)的星上导航系统(TONS),旨在为TDRSS及其后继星TDRSS-Ⅱ的用户提供星上高精度自主导航信息.在探测器平台/远紫外探测器(EP/EUVE)任务上已经进行了一次TONS试验。EP/EUVE任务计划于1992年5月发射,用于飞行验证使用前向链路定时跟踪业务的系统。本文概述了TDRSS的星载导航系统,它既可用于EP/EUVE试验又可用于未来的TONS用户。讨论了系统设计目标,给出了TONs研制三个阶段的运行框架。文中描述了TONs研制的第一个阶段,即在EP上进行试验,内容包括硬件特性、信号采集过程、星上数据采集以及在TONS地面支持系统(TGSS)的飞行仿真环境中进行的地面数据处理。TONs的第二个研制阶段是开发一个完整的TONS I系统,它在星上利用前向链路S波段定时业务提供的多卜勒数据确定轨道和频率。文中对该阶段进行的试验进行了评估并提出改进措施,另外还提出了一种保持星上时间与ToNs Ⅰ时间同步的方法。第三个阶段,即TONSⅡ系统,利用不定时前向链路S波段信标业务连续产生的多卜勒数据和伪距数据在星上确定轨道、时间和频率。文中描述了支持TONs Ⅱ所需的改进。

关键词：跟踪与数据中继卫星系统 TDRSS 星上导航系统 TON5 自主导航

Additive manufacturing of flexible 3D surface electrodes for electrostatic adhesion control and smart robotic gripping

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摩擦:英文版 2023年第11期11卷 1974-1986页

作者： Dong Geun KIM Hyeongmin JE AJohn hart Sanha KIM Department of Mechanical Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea Department of Mechanical Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA

Mechanically flexible surface structures with embedded conductive electrodes are attractive in contact-based devices,such as those used in reversible dry/adhesion and tactile *** shapes of the surface structures strongly determine the contact behavior and therefore the resulting adhesion and sensing functionalities;however,available features are often restricted by fabrication ***,we additively manufacture elastomeric structure arrays with diverse angles,shapes,and sizes;this is followed by integration of conductive nanowire *** fabricated flexible three-dimensional(3D)surface electrodes are mechanically compliant and electrically conductive,providing multifunctional ability to sense touch and to switch adhesion via a combined effect of shear-and electro *** designed soft,anisotropic flexible structures to mimic the gecko’s reversible adhesion,which is governed by van der Waals forces;we integrated nanowires to further manipulate the localized electric field among the adjacent flexible 3D surface electrodes to provide additional means to digitally tune the electrostatic attraction at the contact *** addition,the composite surface can sense the contact force via capacitive *** our flexible 3D surface electrodes,we demonstrate a complete soft gripper that can grasp diverse convex objects,including metal,ceramic,and plastic products,as well as fresh fruits,and that exhibits 72%greater electroadhesive gripping force when voltage is applied.

关键词： electroadhesion tactile sensing robotic gripper additive manufacturing dry adhesive