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Selection and quality assessment of Landsat data for the north American forest dynamics forest history maps of the US

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International Journal of Digital Earth 2016年第10期9卷 963-980页

作者： Karen Schleeweis samuel n.goward Chengquan Huang John L.Dwyer Jennifer L.Dungan Mary A.Lindsey Andrew Michaelis Khaldoun Rishmawi Jeffery G.Masek Forest Inventory and Analysis US Forest ServiceRocky Mountain Research StationOgdenUTUSA Department of Geographical Sciences University of MarylandCollege ParkMDUSA U.S.Geological Survey Earth Resources Observation and Science(EROS)Center Sioux FallsSDUSA nASA Ames Research Center Moffett FieldCAUSA Climate Program Office NOAAWashingtonDCUSA nASA Ames Research Center University Corporation Monterey BayMoffett FieldCAUSA nASA Goddard Space Flight Center GreenbeltMDUSA

Using the nASA Earth Exchange platform,the north American Forest Dynamics(nAFD)project mapped forest history wall-to-wall,annually for the contiguous US(1986–2010)using the Vegetation Change Tracker *** with any effort to identify real changes in remotely sensed time-series,data gaps,shifts in seasonality,misregistration,inconsistent radiometry and cloud contamination can be sources of *** discuss the nAFD image selection and processing stream(nISPS)that was designed to minimize these sources of *** nISPS image quality assessments highlighted issues with the Landsat archive and metadata including inadequate georegistration,unreliability of the pre-2009 L5 cloud cover assessments algorithm,missing growing-season imagery and paucity of clear *** maps of Landsat 5–7 image quantities and qualities are presented that offer novel perspectives on the growing-season archive considered for this *** 150,000+Landsat images were considered for the nAFD ***,one high quality cloud-free image in each year or a total of 12,152 images would be ***,to accommodate data gaps and cloud/shadow contamination 23,338 images were *** 220 specific path-row image years no acceptable images were found resulting in data gaps in the annual national map products.

关键词： Landsat forest cover change time-series mapping forest disturbance north American forest dynamics nasa earth exchange

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Development of time series stacks of Landsat images for reconstructing forest disturbance history

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International Journal of Digital Earth 2009年第3期2卷 195-218页

作者： Chengquan Huang samuel n.goward Jeffrey G.Masek Feng Gao Eric F.Vermote nancy Thomas Karen Schleeweis Robert E.Kennedy Zhiliang Zhu Jeffery C.Eidenshink John R.G.Townshend Department of Geography University of Maryland2181 LeFrak HallCollege ParkMD 20742USA Code 614.4Biospheric Sciences NASA Goddard Space Flight CenterGreenbeltMD 20771USA Earth Resources Technology Inc. 10810 Guilford Rd.Annapolis JunctionMD 20701USA USDA Forest Service Pacific northwest Research Station 3200 SW Jefferson WayCorvallisOR 97331USA U.S.Geological Survey 12201 Sunrise Valley DriveRestonVA 20192USA USGS Earth Resources Observation and Science(EROS) Sioux FallsSD 57198USA

Forest dynamics is highly relevant to a broad range of earth science studies,many of which have geographic coverage ranging from regional to global *** the temporally dense Landsat acquisitions available in many regions provide a unique opportunity for understanding forest disturbance history dating back to 1972,large quantities of Landsat images will need to be analysed for studies at regional to global *** will not only require effective change detection algorithms,but also highly automated,high level preprocessing capabilities to produce images with subpixel geolocation accuracies and best achievable radiometric consistency,a status called imagery-ready-to-use(IRU).This paper describes a streamlined approach for producing IRU quality Landsat time series stacks(LTSS).This approach consists of an image selection protocol,high level preprocessing algorithms and IRU quality verification *** high level preprocessing algorithms include updated radiometric calibration and atmospheric correction for calculating surface reflectance and precision registration and orthorectification routines for improving geolocation *** automated routines have been implemented in the Landsat Ecosystem Disturbance Adaptive System(LEDAPS)designed for processing large quantities of Landsat *** characteristics of the LTSS developed using this approach are discussed.

关键词： Landsat time series stack imagery-ready-to-use LEDAPS forest change

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The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury

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neural Regeneration Research 2025年第11期20卷 3317-3329页

作者： Jennifer M.Colón-Mercado Aranza I.Torrado-Tapias Iris K.Salgado Jose M.Santiago samuel E.Ocasio Rivera Dina P.Bracho-Rincon Luis H.Pagan Rivera Jorge D.Miranda Department of Physiology University of Puerto RicoMedical Sciences CampusSan JuanPRUSA national Institutes of Health National Human Genome Research InstituteBethesdaMDUSA Universidad Central del Caribe School of MedicineBayamónPRUSA University of Puerto Rico Carolina CampusCarolinaPRUSA Institute of neurobiology San JuanPRUSA

In addition to the loss of motor function,~60% of patients develop pain after spinal cord *** cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic *** can lead to the formation of new connections triggering abnormal sensory *** excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and *** previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator *** this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord *** hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant *** and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical *** treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent *** expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on *** rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased

关键词： allodynia central neuropathic pain EAAT-1/GLAST EAAT-2/GLT-1 glutamate transporters selective estrogen receptor modulator sexual dimorphism spinal cord injury trauma

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卫星生物气候学研究

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气象科技 1990年第2期18卷 33-38页

作者： samuel n. goward 曾晓梅马里兰大学地理系遥感系统实验室

对地球陆地的卫星遥感大大增进了人们对全球植被型的了解.综合可见光与近红外波段的反射率观测值可以大致反映植被枝叶的存在,状况及数量.在气候研究中,这种资料相当有价值,因为气候变量与植被枝叶有关.植被枝叶的存在主要由局地热量与... 详细信息

对地球陆地的卫星遥感大大增进了人们对全球植被型的了解.综合可见光与近红外波段的反射率观测值可以大致反映植被枝叶的存在,状况及数量.在气候研究中,这种资料相当有价值,因为气候变量与植被枝叶有关.植被枝叶的存在主要由局地热量与水分状况的结合决定.反过来,枝叶的存在又决定了局地光合率,影响表面反射率,影响局地蒸散率以及地面能量和质量平衡的其它要素.这些遥感资料的应用第一次为直接研究气候与植被之间的相互作用提供了连贯的全球性资料.这些进展正在被气候学研究接收,将会促进大尺度生物气候学的发展.预计在不久的将来,遥感技术以及人们对这些技术的了解将继续迅速发展,并且会推动卫星气候学这一新领域的重大进展.

关键词：生物气候学遥感资料遥感技术卫星遥感卫星气候学表面反射率近红外波段 AVHRR 叶面积指数 nOAA

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Multi-Model Communication and Data Assimilation for Mitigating Model Error and Improving Forecasts

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Chinese Annals of Mathematics,Series B 2019年第5期40卷 689-720页

作者： Yian CHEn samuel n.STECHMAnn Department of Mathematics University of Wisconsin-MadisonMadisonWI 53706USA Department of Statistics University of ChicagoChicagoIL 60637USA Department of Mathematics and Department of Atmospheric and Oceanic Sciences University of Wisconsin-MadisonMadisonWI 53706USA

Models for weather and climate prediction are complex, and each model typically has at least a small number of phenomena that are poorly represented, such as perhaps the Madden-Julian Oscillation(MJO for short) or El nino-Southern Oscillation(EnSO for short) or sea ice. Furthermore, it is often a very challenging task to modify and improve a complex model without creating new deficiencies. On the other hand, it is sometimes possible to design a low-dimensional model for a particular phenomenon, such as the MJO or EnSO, with significant skill, although the model may not represent the dynamics of the full weather-climate system. Here a strategy is proposed to mitigate these model errors by taking advantage of each model’s strengths. The strategy involves inter-model data assimilation, during a forecast simulation, whereby models can exchange information in order to obtain more faithful representations of the full weather-climate system. As an initial investigation, the method is examined here using a simplified scenario of linear models, involving a system of stochastic partial differential equations(SPDEs for short)as an imperfect tropical climate model and stochastic differential equations(SDEs for short) as a low-dimensional model for the MJO. It is shown that the MJO prediction skill of the imperfect climate model can be enhanced to equal the predictive skill of the lowdimensional model. Such an approach could provide a route to improving global model forecasts in a minimally invasive way, with modifications to the prediction system but without modifying the complex global physical model itself.

关键词： MJO Multi-Model communication Data assimilation Kalman filter algorithm

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Combining material characterization with single and multi-oxyanion adsorption for mechanistic study of chromate removal by cationic hydrogel

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Journal of Environmental Sciences 2011年第6期23卷 1004-1010页

作者： Irene M.C.Lo samuel C.n.Tang Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong KongChina

Cationic hydrogel with magnetic property was synthesized via radical polymerization and its removal capacity of chromate from contaminated water was found to be 200 mg/*** Fourier transform infrared spectroscopy（FT-IR） study,the mechanism of chromate removal by hydrogel was found to be non-specific adsorption,mainly due to ion exchange,as evidenced by the positively charged functional group,trimethyl ammonium-n＋（CH3）3,in the *** were accordingly determined by testing di？erent oxyanion adsorption onto the *** results of the chromate adsorption experiments illustrated that the amount of chromate adsorbed was nearly equal to that of the chloride released from the hydrogel,which is part of the evidence for ion *** and multi-oxyanion adsorption experiments were also performed,and it was demonstrated that ion removal was species independent,but charge dependent,another characteristic of the ion exchange *** was found that the same Langmuir model can be applied to best fit the findings of single and multi-oxyanion adsorption,which further indicates the mechanism of chromate removal is attributed to ion *** view of the above,the background anions compete for adsorption sites with chromate,evidenced by inhibitive chromate removal in the presence of background electrolytes in the batch studies,further echoing the ion exchange mechanism.

关键词： adsorption magnetic hydrogel mechanism ion exchange oxyanion

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Uncertainty and filtering of hidden Markov models in discrete time

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Probability, Uncertainty and Quantitative Risk 2020年第1期5卷 68-101页

作者： samuel n.Cohen Mathematical Institute University of OxfordWoodstock RoadOxfordUK

We consider the problem of filtering an unseen Markov chain from noisy observations,in the presence of uncertainty regarding the parameters of the processes *** the theory of nonlinear expectations,we describe the uncertainty in terms of a penalty function,which can be propagated forward in time in the place of the *** also investigate a simple control problem in this context.

关键词： Filtering Optimal control Robustness nonlinear expectation

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Analytical modeling and simulation of germanium single gate silicon on insulator TFET

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Journal of Semiconductors 2014年第3期35卷 25-28页

作者： T.S.Arun samuel n.B.Balamurugan Department of Electronics and Communication Engineering Thiagarajar College of Engineering

This paper proposes a new two dimensional（2D） analytical model for a germanium（Ge） single gate silicon-on-insulator tunnel field effect transistor（SG SOI TFET）. The parabolic approximation technique is used to solve the 2D Poisson equation with suitable boundary conditions and analytical expressions are derived for the surfacepotential,*** is derived further by using the electric fields. The results show that Ge based TFETs have significant improvements ***heanalytical model results with the technology computer aided design（TCAD） simulation results and also comparing them with results from a silicon based TFET.

关键词： tunnel field effect transistor(TFET) analytical modelling Poisson equation surface potential electric field

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Balanced and Unbalanced Components of Moist Atmospheric Flows with Phase Changes

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Chinese Annals of Mathematics,Series B 2019年第6期40卷 1005-1038页

作者： Alfredo n.WETZEL Leslie M.SMITH samuel n.STECHMAnn Jonathan E.MARTIn Department of Mathematics University of Wisconsin-MadisonMadisonWI 53706USA Department of Mathematics and Department of Engineering Physics University of Wisconsin-MadisonMadisonWI 53706USA Department of Mathematics and Department of Atmospheric and Oceanic Sciences University of Wisconsin-MadisonMadisonWI 53706USA Department of Atmospheric and Oceanic Sciences University of Wisconsin-MadisonMadisonWI 53706USA

Atmospheric variables(temperature, velocity, etc.) are often decomposed into balanced and unbalanced components that represent low-frequency and high-frequency waves, respectively. Such decompositions can be defined, for instance, in terms of eigenmodes of a linear operator. Traditionally these decompositions ignore phase changes of water since phase changes create a piecewise-linear operator that differs in different phases(cloudy versus non-cloudy). Here we investigate the following question: How can a balanced–unbalanced decomposition be performed in the presence of phase changes? A method is described here motivated by the case of small Froude and Rossby numbers,in which case the asymptotic limit yields precipitating quasi-geostrophic equations with phase changes. Facilitated by its zero-frequency eigenvalue, the balanced component can be found by potential vorticity(PV) inversion, by solving an elliptic partial differential equation(PDE), which includes Heaviside discontinuities due to phase changes. The method is also compared with two simpler methods: one which neglects phase changes, and one which simply treats the raw pressure data as a streamfunction. Tests are shown for both synthetic, idealized data and data from Weather Research and Forecasting(WRF) model simulations. In comparisons, the phase-change method and no-phase-change method produce substantial differences within cloudy regions, of approximately 5K in potential temperature, due to the presence of clouds and phase changes in the data. A theoretical justification is also derived in the form of a elliptic PDE for the differences in the two streamfunctions.

关键词： Potential vorticity inversion Moist atmospheric dynamics Slow-fast systems Balanced-unbalanced decomposition Elliptic partial differential equations

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Hydration Assessment of Athletes

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中国运动医学杂志 2006年第2期25卷 238-244页

作者： samuel n.Cheuvront Michael n.Sawka Thermal and Mountain Medicine Division U. S . Army Research Institute of Environmental Medicine Natick USA

KEY POInTS Although there is no scientific consensus for 1 ） how best to assess the hydration status of athletes, 2）what criteria to use as acceptable outcome measurements, or 3） the best time to apply practical assessment methods, there are methods that can be used toprovide athletes with useful feedback about their hydration status.

关键词：运动员评价水合作用运动医学

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