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Alternative expressions for stand diameter in complex forests

Forest Ecosystems 2023年第3期10卷 328-336页

作者： Mark J.Ducey john a.kershaw jr. Department of Natural Resources and the Environment University of New HampshireDurhamNHUSA Faculty of Forestry and Environmental Management University of New BrunswickFrederictonNBCanada

Quadratic mean diameter is the most frequently reported descriptor of the diameter distribution of *** such,it is often used as an indicator of forest stand structure,developmental stage,and ecological and economic ***,quadratic mean diameter can be heavily influenced by the presence or absence of large numbers of small stems in lower canopy strata,and it is also sensitive to left-truncation of the diameter distribution,making its interpretation across inventories with different protocols ***,we examine three alternative expressions of stand diameter:the arithmetic and quadratic mean diameter of the thickest 100 trees per hectare,and the basal area-weighted mean *** data from the United States Forest Inventory and Analysis program for New York and New England,these alternative expressions showed closer correlation with multiple stand structural variables than did quadratic mean diameter,including merchantable cubic and board foot volume per hectare,aboveground live tree carbon per hectare,and total number of live and dead standing trees greater than 40 cm diameter at breast height per hectare(previously proposed as an index of old-growth structure).Arithmetic and quadratic mean diameter of the thickest 100 trees per hectare showed nearly identical performance,and the strongest correlations across the *** develop closed-form expressions for these variables when the diameter distribution is a Weibull,and illustrate their behavior relative to quadratic mean diameter for that *** the reasons for prevalence of quadratic mean diameter as an indicator remain valid,we suggest that these alternative measures should be more widely reported and analyzed to give a more informative depiction of stand structure and development in complex forests.

关键词： Forest structure Diameter at breast height Weibull distribution

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Can a multistage approach improve individual tree mortality predictions across the complex mixed-species and managed forests of eastern North America?

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Forest Ecosystems 2023年第1期10卷 21-30页

作者： Cen Chen john kershaw jr.Aaron Weiskittel Elizabeth McGarrigle Center for Research on Sustainable Forests University of MaineOronoME04469USA Faculty of Forestry&Environmental Management University of New BrunswickFrederictonNBE3B 5A3Canada Nova Scotia Department of Natural Resources HalifaxNSB3J 3M8Canada

Tree mortality plays a fundamental role in the dynamics of forest ecosystems,yet it is one of the most difficult phenomena to accurately *** modeling strategies have been developed to improve individual tree mortality *** less explored strategy is the use of a multistage modeling *** improvements from this approach have remained largely *** this study,we developed a novel multistage approach and compared its performance in individual tree mortality predictions with a more conventional approach using an identical individual tree mortality model *** permanent plot data(n=9442)covering the Acadian Region of North America and over multiple decades(1965–2014)were used in this *** results indicated that the model behavior with the multistage approach better depicted the observed mortality and showed a notable improvement over the conventional *** difference between the observed and predicted numbers of dead trees using the multistage approach was much smaller when compared with the conventional *** addition,tree survival probabilities predicted by the multistage approach generally were not significantly different from the observations,whereas the conventional approach consistently underestimated mortality across species and overestimated tree survival probabilities over the large range of DBH in the *** new multistage approach also predictions of zero mortality in individual plots,a result not possible in conventional ***,the new approach was more tolerant of modeling errors because it based estimates on ranked tree mortality rather than error-prone predicted ***,this new multistage approach deserves to be considered and tested in future studies.

关键词： Tree mortality modeling Mortality disaggregation Mixed effect model Annualization Mixed forests

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Development of a 3D model for particle-wall collision and induced rotation and its influence on particle trajectories

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Particuology 2024年第11期94卷 211-228页

作者： Cairen Miranda john Palmore jr. Department of Mechanical Engineering Virginia TechBlacksburg24060VAUSA Department of Mechanical Engineering University of WashingtonSeattle98195WAUSA

The present research focuses on improving the prediction of rotating particle *** particle-surface collision models do not accurately predict the particle rebound when taking rotation into *** data,such as the studies by Gorham and Kharaz(2000),Buck,Tang,Heinrich,Deen and Kuipers(2017),and Dong and Moys(2006)show that the Tsuji,Oshima and Morikawa(1985)model is inaccurate due to the incorrect tangential coefficient of restitution ***,Kuipers,Mohd Salleh,Stein,and Seville(2001)introduced a similar model to the work by Tsuji et al.(1985)which includes a tangential coefficient of restitution but is only in two dimensions and does not consider out of plane *** work re-derives the particle collision model from the impulse equations for binary collisions in 3D while considering rotating *** derived equations in this work compares well to experimental particle-surface impact *** implications of this model are seen by investigating erosion due to particle collision in a simple pipe *** is shown that Tsuji et al.(1985)over predicts the *** small differences in particle trajectories between the present model and the Tsuji et al.(1985)model will grow in complex flows with multiple close range particle impacts leading to inaccurate erosion predictions which will negatively impact the design of turbomachinery and pneumatic pipes.

关键词： Particle collisions CFD Rotation Three dimensional

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An imputation/copula-based stochastic individual tree growth model for mixed species Acadian forests： a case study using the Nova Scotia permanent sample plot network

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Forest Ecosystems 2017年第4期4卷 251-263页

作者： john A. kershaw jr.Aaron R. Weiskittel Michael B. Lavigne Elizabeth McGarrigle University of New Brunswick FrederictonNBCanada University of Maine OroooMEUSA Atlantic Forestry Centre Natural Resources Canada.FrederiaooNBCanada Nova Scotia Natural Resources Forestry DivisionTruroNS B2N 0G9UK.

Background： A novel approach to modelling individual tree growth dynamics is proposed. The approach combines multiple imputation and copula sampling to produce a stochastic individual tree growth and yield projection system. Methods： The Nova Scotia, Canada permanent sample plot network is used as a case study to develop and test the modelling approach. Predictions from this model are compared to predictions from the Acadian variant of the Forest Vegetation Simulator, a widely used statistical individual tree growth and yield model. Results： Diameter and height growth rates were predicted with error rates consistent with those produced using statistical models. Mortality and ingrowth error rates were higher than those observed for diameter and height, but also were within the bounds produced by traditional approaches for predicting these rates. Ingrowth species composition was very poorly predicted. The model was capable of reproducing a wide range of stand dynamic trajectories and in some cases reproduced trajectories that the statistical model was incapable of reproducing. Conclusions： The model has potential to be used as a benchmarking tool for evaluating statistical and process models and may provide a mechanism to separate signal from noise and improve our ability to analyze and learn from large regional datasets that often have underlying flaws in sample design.

关键词： Nearest neighbor imputation Copula sampling Individual tree growth model Mortality Ingrowth Mixed species stand development Acadian forests Nova Scotia

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Emerging complexity and new roles for the RIG-I-like receptors in innate antiviral immunity

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Virologica Sinica 2015年第3期30卷 163-173页

作者： john S.Errett Michael Gale jr. Center for Innate Immunity and Immune Disease Department of Immunology School of Medicine University of Washington

Innate immunity is critical for the control of virus infection and operates to restrict viral susceptibility and direct antiviral immunity for protection from acute or chronic viral-associated diseases including cancer. RIG-I like receptors(RLRs) are cytosolic RNA helicases that function as pathogen recognition receptors to detect RNA pathogen associated molecular patterns(PAMPs) of virus infection. The RLRs include RIG-I, MDA5, and LGP2. They function to recognize and bind to PAMP motifs within viral RNA in a process that directs the RLR to trigger downstream signaling cascades that induce innate immunity that controls viral replication and spread. Products of RLR signaling also serve to modulate the adaptive immune response to infection. Recent studies have additionally connected RLRs to signaling cascades that impart inflammatory and apoptotic responses to virus infection. Viral evasion of RLR signaling supports viral outgrowth and pathogenesis, including the onset of viral-associated cancer.

关键词： RIG-I MDA5 pattern recognition receptor pathogen associated molecular pattern innate immunity virus infection

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Organizational Behavior Don Hellriegel, john W. Slocum, jr.

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2007年

作者： Don Hellriegel john W. Slocum jr.

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Selling : building partnerships Barton A. Weitz, Stephen B. Castleberry, john F. Tanner, jr. 5th ed.

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丛书名： The Irwin/McGraw-Hill series in marketing

2004年

作者： Barton A. Weitz Stephen B. Castleberry john F. Tanner jr.

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THE NATURAL LAW FOUNDATION OF THE MARKET

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Frontiers of Law in China-Selected Publications from Chinese Universities 2020年第4期15卷 409-430页

作者： GUO Rui john S.Baker,jr. Harvard Law School CambridgeMAUnited States School of Law Renmin University of ChinaBeijing 100872China University of London LondonUK The Center for the Constitution Georgetown University Law CenterWashington D.C.USA Louisiana State University Law Center Baton RougeLouisiana 70803USA

In answering three important questions related to natural law,this paper offers a coherent explanation of the *** argue that the market,rather than a mechanism that simply serves narrow self-interests,finds its legitimacy in the ethical origins of the market *** need for law to support and sustain the market,including by imposing necessary limits on the freedom of the market players,flows from those ethical origins.

关键词： natural law market regulation the principle of subsidiarity

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Effects of vertical position on trematode parasitism in larval anurans

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Current Zoology 2019年第6期65卷 657-664页

作者： Jacob R.JONES Camille L.STEENROD john A.MARINO jr. Biology Department Bradley UniversityPeoriaILUSA Department of Geography University of MarylandCollege ParkMDUSA

Spatial distributions of animals can affect interactions with their natural enemies,such as parasites,and thus have important implications for host-parasite *** spatial variation in infection risk has been explored in many systems at the landscape scale,less attention has been paid to spatial structure at smaller ***,we explore a hypothesized relationship between a common spatial variable,vertical position,and risk of parasite infection in a model aquatic system,larval frogs(Rana)and trematode(Digenea)*** position is relevant to this system given evidence that the densities of snail first intermediate hosts,tadpole second intermediate hosts,and trematode infective stages can vary with *** test the effects of depth on infection risk of larval frogs by trematodes,we performed two enclosure experiments,one in the laboratory and one in the field,in which larval frogs in cages just below the water surface or near the bottom of the water column were exposed to *** with near-surface cages,mean infection load(number of cysts)in tadpoles in near-bottom cages was 83%higher after 48-h exposures in the laboratory and 730%higher after 10-day exposures in the *** findings thus indicate that infection risk depends on depth,which may have adaptive significance,as tadpoles have previously been shown to change vertical position in response to parasite *** results motivate future work examining vertical variation in infection risk and may have broader implications for host-parasite dynamics and evolution of host and parasite behavior.

关键词： avoidance behavior cercariae Echinostomatidae host-parasite interactions Rana spatial structure

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Selling Building Parterships Barton A. Weitz, Stephen B. Castleberry, john F. Tanner, jr. 6th ed.

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2007年

作者： Barton A. Weitz Stephen B. Castleberry john F. Tanner jr.

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