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Applying robust design to study the effects of stratigraphic characteristics on brittle failure and bump potential in a coal mine

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International Journal of Mining Science and Technology 2018年第1期28卷 137-144页

作者： Bo-Hyun Kim Mark K.larson Heather E.Lawson Spokane Mining Research Division NIOSH/CDC

Bumps and other types of dynamic failure have been a persistent, worldwide problem in the underground coal mining industry, spanning *** example, in just five states in the *** 1983 to 2014,there were 388 reportable *** significant advances in mine design tools and mining practices,these events continue to *** conditions have been associated with bump potential, such as the presence of stiff units in the local *** effect of a stiff sandstone unit on the potential for coal bumps depends on the location of the stiff unit in the stratigraphic column, the relative stiffness and strength of other structural members, and stress concentrations caused by *** study describes the results of a robust design to consider the impact of different lithologic risk factors impacting dynamic failure *** the inherent variability of stratigraphic characteristics in sedimentary formations,such as thickness, engineering material properties, and location, is significant and the number of influential parameters in determining a parametric study is large, it is impractical to consider every simulation case by varying each parameter ***, to save time and honor the statistical distributions of the parameters, it is necessary to develop a robust design to collect sufficient sample data and develop a statistical analysis method to draw accurate conclusions from the collected *** this study,orthogonal arrays, which were developed using the robust design, are used to define the combination of the(a) thickness of a stiff sandstone inserted on the top and bottom of a coal seam in a massive shale mine roof and floor,(b) location of the stiff sandstone inserted on the top and bottom of the coal seam,and(c) material properties of the stiff sandstone and contacts as interfaces using the 3-dimensional numerical model, *** completion of the numerical experiments, statistical and multivariate analysis are performed using

关键词： Bumps Robust design FLAc3D Plastic dissipated energy Multiple regression

The P-T-t-D evolution of the Mahabharat,east-central Nepal:The out-of-sequence development of the Himalaya

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Geoscience Frontiers 2022年第2期13卷 372-382页

作者： Kyle P.larson Sudip Shrestha Mathieu Soret Matthijs Smit Department of Earth Environmental and Geographic SciencesUniversity of British Columbia Okanagan3247 University WayKelownaBC V1V 1V7Canada Department of Earth Ocean and Atmospheric SciencesUniversity of British Columbia Vancouver2020-2207 Main MallVancouverBC V6T 1Z4Canada

A garnet-bearing schist from the southernmost such exposure along the Himalaya in east central Nepal records prograde metamorphism at 32.4±0.3 *** equilibria modelling,combined with Ti-in-biotite and quartz caxis thermometry,outline a tight-to-hairpin pressure-temperature(P-T)path extending from~515℃ and 5.5 kbar to peak conditions at~575℃ and 7 kbar followed by deformation during the retrograde phase at 480-515℃ and 6-7 *** new geochronology data place an upper bound on the evolution of metamorphism and deformation in the frontal-most part of the Himalaya,which lasted until 17.5 Ma,as indicated by previously published ^(40)Ar/^(39)Ar *** P-T-time data from this part of the Himalaya,as well as that from more hinterlandward portions of the orogen,outline a progressive,stepwise,commonly out-of-sequence *** data from along the orogen indicates that this evolution is not a local phenomenon,but instead characterizes the tectonics of this system as a whole.

关键词： Himalaya Metamorphism Kinematics Lu-Hf Geochronology Nepal

carotid artery endarterectomy in patients with symptomatic non-stenotic carotid artery disease

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Stroke & Vascular Neurology 2022年第3期7卷 251-257页

作者： Valentina Nardi John c Benson Anthony S larson Waleed Brinjikji Luca Saba Fredric B Meyer Giuseppe Lanzino Amir Lerman Luis E Savastano Department of cardiovascular Diseases Mayo ClinicRochesterMinnesotaUSA Radiology Mayo ClinicRochesterMinnesotaUSA Radiology Azienda Ospedaliero UniversitariaCagliariItaly Neurosurgery Mayo ClinicRochesterMinnesotaUSA

Object We sought to determine the safety and efficacy in secondary stroke prevention of carotid endarterectomy(cEA)in patients with symptomatic non-stenotic carotid artery disease(SyNc).Methods This was a single-centre retrospective case *** patients who underwent cEA for unilateral anterior circulation cerebrovascular events with ipsilateralcarotid stenosis from 2002 to 2020 were *** hallmarks including the degree of luminal stenosis and the presence of various vulnerable plaque characteristics(eg,intraplaque haemorrhage(IPH)on MR angiography,ulceration or low-density plaque on cT angiography)were *** presence of vulnerable plaque characteristics was compared between arteries ipsilateral to the ischaemic event and contralateral *** prevalence of perioperative/intraoperative complications,as well as recurrent ischaemic events at follow-up was *** Thirty-two patients were included in the analysis,of which 25.0%were *** arteries ipsilateral to an ischaemic event had a significantly higher prevalence of IPH when compared with contralateral arteries(80.0%vs 0.0%;pchaemia 1 day following cEA which resolved without *** a median follow-up of 18.0 months(IQR 5.0-36.0),only one patient(3.1%)experienced a transient neurologic deficit with complete resolution(annualised rate of recurrent stroke after cEA of 1.5%for a total follow-up of 788 patient-months following cEA).All other patients(31/32,96.9%)were free of recurrent ischaemic *** cEA appears to be safe and well-tolerated in patients with *** studies with larger cohorts and longer follow-up intervals are needed in order to determine the role of cEA in this patient population.

关键词： patients carotid prevention

Diffusion-weighted magnetic resonance imaging to predict response of hepatocellular carcinoma to chemoembolization

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World Journal of Gastroenterology 2010年第25期16卷 3161-3167页

作者： Johnathan c chung Neel K Naik Robert J Lewandowski Mary F Mulcahy Laura M Kulik Kent T Sato Robert K Ryu Riad Salem andre. c larson Reed A Omary Department of Radiology North-western University Chicago IL 60611 United States clinical Sciences Research Division Gastrointestinal Oncology Program Robert H. Lurie Comprehensive Cancer Center Chicago IL 60611 United StatesMary F Mulcahy Department of Medicine Division of Hema-tology and Oncology Northwestern Memorial Hospital Chi-cago IL 60611 United States Department of Hepatology Northwestern Uni-versity Chicago IL 60611 United States Reed A Omary Department of Biomedi-cal Engineering Northwestern University Chicago IL 60611 United States

AIM: To investigate whether intra-procedural diffusion- weighted magnetic resonance imaging can predict response of hepatocellular carcinoma (Hcc) during trans- catheter arterial chemoembolization (TAcE). METHODS: Sixteen patients (15 male), aged 59 ±11 years (range: 42-81 years) underwent a total of 21 separate treatments for unresectable Hcc in a hybrid magnetic resonance/interventional radiology suite. Ana- tomical imaging and diffusion-weighted imaging (b = 0, 500 s/mm2) were performed on a 1.5-T unit. Tumor enhancement and apparent diffusion coefficient (ADc, mm2/s) values were assessed immediately before and at 1 and 3 mo after TAcE. We calculated the percent change (Pc) in ADc values at all time points. We compared follow-up ADc values to baseline values using a paired t test (α = 0.05). RESULTS: The intra-procedural sensitivity, specificity, and positive and negative predictive values (%) for detecting a complete or partial 1-mo tumor response using ADc Pc thresholds of ±5%, ±10%, and ±15% were 77, 67, 91, and 40; 54, 67, 88, and 25; and 46, 100, 100, and 30, respectively. There was no clear predictive value for the 3-mo follow-up. compared to baseline, the immediate post-procedure and 1-mo mean ADc values both increased; the latter obtaining statistical significance (1.48 ± 0.29 mm2/s vs 1.65 ± 0.35 × 10-3 mm2/s, P cONcLUSION: Intra-procedural ADc changes of > 15% predicted 1-mo anatomical Hcc response with the greatest accuracy, and can provide valuable feedback at the time of TAcE.

关键词： Hepatocellular carcinoma Transcatheter arterial chemoembolization Diffusion-weighted imaging Apparent diffusion coefficient Functional imaging biomarker

Operations Research: The Science of Better

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Operations Research: The Science of Better

Genetic Relationships Among Soluble carbohydrates, Anthocyanins and Growth characteristics in Leymus (Gramineae) Detected with Molecular Markers

中国运筹学会第七届学术交流会

作者： Richard c.larson Massachusetts Institute of Technology cambridge Massachusetts 02139 USA President-Elect - INFORMS Institute For Operations Research and the Management Sciences

It is a deep honor for me today to give this talk before the most distinguished operationsresearchers in china. I sincerely thank you for the opportunity. I am particularly indebtedto Prof. Xiangsun ZHANG, Academy of Mathematics and System Sciences, for inviting me topresent this lecture. Thank you! Operations Research, co-founded in World War Ⅱin the USA by Philip M. Morse, GeorgeKimball, Bernard Koopman and others, in the U.K. by Frederick Lanchester, Patrick Blackett,Frank Yates and others, was designed as an empirical science using all relevant scientific methodsto solve managerial decision problems.

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Acta Botanica Sinica 2002年第10期44卷 1173-1181页

作者：胡赞民 Steven R. larson Thomas A. JONES Richard R-c. WANG 中国科学院遗传与发育生物学研究所北京100101 U.S. Department of Agriculture

Low-temperature soluble carbohydrate accumulations are commonly associated with anthocyanin coloration, attenuated growth and cold adaptation of cool-season grasses. The vrn-1 gene has potent effects on vernalization requirement, growth, and soluble carbohydrate accumulations of the winter-annual Triticeae species. Two hundred and four unmapped AFLP markers and genome-specific DNA markers genetically linked to the vrn-1 gene were used to detect QTL controlling soluble carbohydrate accumulations, anthocyanin coloration and growth characteristics in a segregating population derived from open pollinated Leymus cinereus x L. triticoides hybrids. These perennial Triticeae grasses are distinguished by adaptation and growth habit. As expected, positive trait correlations and pleiotropic gene effects were detected for soluble carbohydrate accumulations and anthocyanin coloration. Likewise, positive trait correlations and pleiotropic gene effects were detected for tillering, leaf development, leaf growth, regrowth and rhizome spread. However, soluble carbohydrate accumulations were not associated with attenuated growth. In fact, several DNA marker alleles, including one near vrn-Ns1, had positive effects on soluble leaf carbohydrate concentrations and low temperature growth. The corresponding DNA marker near vrn-Ns1 had more specific effects on tillering. We speculate that vrn-1 exerts quantitative effects on low-temperature soluble leaf carbohydrate accumulations and growth habit of the perennial Leymus. However, a number of other DNA markers displayed highly significant effects on soluble carbohydrate accumulations and various growth characteristics. Findings indicate that anthocyanin coloration may be a useful phenotypic marker for soluble carbohydrate accumulation. Although variation for soluble carbohydrates was not associated with attenuated growth in this population, this trait was under genetic control.

关键词： Leymus molecular markers genetic relationship

Unfolding the complexity of phonon quasi-particle physics in disordered materials

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npj computational Materials 2020年第1期6卷 1620-1627页

作者： Sai Mu Raina J.Olsen Biswanath Dutta Lucas Lindsay German D.Samolyuk Tom Berlijn Eliot D.Specht Ke Jin Hongbin Bei Tilmann Hickel Bennet c.larson George M.Stocks Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Max-Planck-Institut für Eisenforschung GmbH D-40237 DüsseldorfGermany center of Nanophase and Material Science Oak Ridge National LaboratoryOak RidgeTN 37831USA computational Science and Engineering Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Materials Department University of CaliforniaSanta BarbaraCA 93106USA

The concept of quasi-particles forms the theoretical basis of our microscopic understanding of emergent phenomena associated with quantum-mechanical many-body ***,the quasi-particle theory in disordered materials has proven difficult,resulting in the predominance of mean-field ***,we report first-principles phonon calculations and inelastic X-ray and neutron-scattering measurements on equiatomic alloys(Nico,NiFe,AgPd,and NiFeco)with force-constant dominant disorder—confronting a key 50-year-old assumption in the Hamiltonian of all mean-field quasi-particle solutions for off-diagonal *** results have revealed the presence of a large,and heretofore unrecognized,impact of local chemical environments on the distribution of the species-pair-resolved force-constant disorder that can dominate phonon *** discovery not only identifies a critical analysis issue that has broad implications for other elementary excitations,such as magnons and skyrmions in magnetic alloys,but also provides an important tool for the design of materials with ultralow thermal conductivities.

关键词： alloys particle phonon

Large-diameter trees dominate snag and surface biomass following reintroduced fire

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Ecological Processes 2020年第1期9卷 475-487页

作者： James A.Lutz Soren Struckman Tucker J.Furniss c.Alina cansler Sara J.Germain Larissa *** Darren J.McAvoy crystal A.Kolden Alistair M.S.Smith Mark E.Swanson andre. J.larson Department of Wildland Resources S.J.and Jessie E.Quinney College of Natural ResourcesUtah State University5230 Old Main HillLoganUtah 84322-5230USA School of Environmental and Forest Sciences University of WashingtonBox 352100SeattleWashington 98195USA Management of complex Systems University of CaliforniaMerced5200 North Lake RoadMercedCalifornia 95343USA Department of Forest Rangelandand Fire SciencesCollege of Natural ResourcesUniversity of Idaho875 Perimeter DriveMoscowIdaho 83844-1133USA School of the Environment Washington State UniversityBox 646410PullmanWashington 99164-6420USA Wilderness Institute W.A.Franke College of Forestry and ConservationUniversity of Montana32 Campus DriveMissoulaMontana 59812USA

The reintroduction of fire to landscapes where it was once common is considered a priority to restore historical forest dynamics,including reducing tree density and decreasing levels of woody biomass on the forest ***,reintroducing fire causes tree mortality that can have unintended ecological outcomes related to woody biomass,with potential impacts to fuel accumulation,carbon sequestration,subsequent fire severity,and forest *** this study,we examine the interplay between fire and carbon dynamics by asking how reintroduced fire impacts fuel accumulation,carbon sequestration,and subsequent fire severity *** pre-fire,and continuing 6 years post-fire,we tracked all live,dead,and fallen trees≥1 cm in diameter and mapped all pieces of deadwood(downed woody debris)originating from tree boles≥10 cm diameter and≥1 m in length in 25.6 ha of an Abies concolor/Pinus lambertiana forest in the central Sierra Nevada,california,*** also tracked surface fuels along 2240 m of planar transects pre-fire,immediately post-fire,and 6 years *** years after moderate-severity fire,deadwood≥10 cm diameter was 73 Mg ha^(−1),comprised of 32 Mg ha^(−1) that persisted through fire and 41 Mg ha^(−1) of newly fallen wood(compared to 72 Mg ha^(−1) pre-fire).Woody surface fuel loading was spatially heterogeneous,with mass varying almost four orders of magnitude at the scale of 20 m×20 m quadrats(minimum,0.1 Mg ha^(−1);mean,73 Mg ha^(−1);maximum,497 Mg ha^(−1)).Wood from large-diameter trees(≥60 cm diameter)comprised 57%of surface fuel in 2019,but was 75%of snag biomass,indicating high contributions to current and future fuel *** of fire does not consume all large-diameter fuel and generates high levels of surface fuels≥10 cm diameter within 6 *** fires are needed to reduce surface fuel loading.

关键词： california Rim Fire Fuel reduction Sierra Nevada mixed-conifer Smithsonian ForestGEO Yosemite Forest Dynamics Plot Yosemite National Park

Re-evaluating monazite as a record of metamorphic reactions

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Geoscience Frontiers 2022年第2期13卷 237-254页

作者： Kyle P.larson Sudip Shrestha John M.cottle carl Guilmette T.Alex Johnson H.Daniel Gibson Félix Gervais Department of Earth Environmental and Geographic SciencesUniversity of British Columbia Okanagan3247 University WayKelownaBC V1V 1V7Canada Fipke Laboratory for Trace Element Research University of British Columbia Okanagan3247 University WayKelownaBC V1V 1V7Canada Department of Earth Science University of CaliforniaSanta BarbaraSanta BarbaraCA 93106-9630USA Géologie et Génie Géologique UniversitéLavalQuébec CityQuebecCanada Department of Earth Sciences Simon Fraser University8888 University DriveBurnabyBC V5A 1S6Canada Départment des Génies civil Géologique et des MinesPolytechnique MontréalMontréalQC H3T 1J4Canada

This study presents a re-examination of historical specimens(DG136 and DG167)from the Monashee complex in the southeastern canadian cordillera that are critical to the current understanding of rare earth element(REE)distribution between garnet and monazite(and other accessory minerals)during ***-hundred and fifty-one new monazite petrochronology spot analyses on 29 different grains across two specimens outline detailed(re)crystallization *** element data collected from the same ablated volume,interpreted in the context of new phase equilibria modelling that includes monazite,xenotime and apatite,link ages to specific portions of the pressure-temperature(P-T)paths followed by the *** linkages are further informed by garnet Lu-Hf geochronology and xenotime *** clockwise P-T paths indicate prograde metamorphism was ongoing by ca.80 Ma in both *** structurally deeper specimen,DG136,records peak P-T conditions of~755-770℃and 8.8-10.4 kbar,interpreted to coincide with(re-)crystallization of low Y monazite at~75-70 ***-rim garnet isopleths from DG167 cross in the observed peak assemblage field at~680℃ and 9.3 *** conditions are interpreted to correspond with low Y monazite(re-)crystallisation at~65 *** specimens record decompression along their retrograde path coincident with high Y 70-55 Ma and 65-55 Ma monazite populations in DG136 and DG167,*** findings broadly agree with those initially reported~20 years ago and confirm early interpretations using trace elements in monazite as generally reliable markers of metamorphic *** phase equilibria modelling and in situ petrochronological analysis,however,provide additional insight into monazite behaviour during anatexis and the effects of potential trace element buffering by REE-bearing phases such as apatite.

关键词： Monazite petrochronology Phase equilibria modelling Geochronology P-T-t paths