Balsam fir self-thinning relationship and its constancy among different ecological regions

2001 ◽  
Vol 31 (6) ◽  
pp. 950-959 ◽  
Author(s):  
Eric Bégin ◽  
Jean Bégin ◽  
Louis Bélanger ◽  
Louis-Paul Rivest ◽  
Stéphane Tremblay
Keyword(s):  
Abies Balsamea ◽  
Principal Component ◽  
Large Data ◽  
The Self ◽  
Balsam Fir ◽  
Data Set ◽  
Ecological Regions ◽  
Density Relationship ◽  
Jackknife Procedure ◽  
Relationship Of

The constancy of balsam fir (Abies balsamea (L.) Mill.) self-thinning relationship has been investigated among four study areas located in different ecological regions of Quebec's humid boreal forest. These four study areas contained respectively 348, 252, 146, and 55 observations (plots × measures) sampled over a period of up to 40 years. A self-thinning fitting method was developed to position objectively the self-thinning lines but, moreover, to allow comparisons among the different study areas. This method relies on principal component analysis to estimate the self-thinning line parameters and on the "jackknife" procedure to provide a standard error of these estimates. Results demonstrate a concordance for the slope (p = 0.136) and the intercept (p = 0.148) among self-thinning relationships of those study areas. The combination of these four study areas in one large data set, to provide a general estimation of balsam fir self-thinning line, has given a slope of –1.441 with a 4.114 intercept which is in agreement with the –3/2 power law of self-thinning. In this study, this law was able to describe the size–density relationship of stands of various ages and growing within different conditions as expressed by the different ecological regions.

scholarly journals The Complete DNA Sequence of the Mitochondrial Genome of a “Living Fossil,” the Coelacanth (Latimeria chalumnae)

Genetics ◽  
1997 ◽  
Vol 146 (3) ◽  
pp. 995-1010 ◽  
Author(s):  
Rafael Zardoya ◽  
Axel Meyer
Keyword(s):  
Mitochondrial Genome ◽  
Tandem Repeats ◽  
Phylogenetic Analyses ◽  
Large Data ◽  
Molecular Data ◽  
Phylogenetic Position ◽  
Data Set ◽  
Living Fossil ◽  
Latimeria Chalumnae ◽  
Relationship Of

The complete nucleotide sequence of the 16,407-bp mitochondrial genome of the coelacanth (Latimeria chalumnae) was determined. The coelacanth mitochondrial genome order is identical to the consensus vertebrate gene order which is also found in all ray-finned fishes, the lungfish, and most tetrapods. Base composition and codon usage also conform to typical vertebrate patterns. The entire mitochondrial genome was PCR-amplified with 24 sets of primers that are expected to amplify homologous regions in other related vertebrate species. Analyses of the control region of the coelacanth mitochondrial genome revealed the existence of four 22-bp tandem repeats close to its 3′ end. The phylogenetic analyses of a large data set combining genes coding for rRNAs, tRNA, and proteins (16,140 characters) confirmed the phylogenetic position of the coelacanth as a lobe-finned fish; it is more closely related to tetrapods than to ray-finned fishes. However, different phylogenetic methods applied to this largest available molecular data set were unable to resolve unambiguously the relationship of the coelacanth to the two other groups of extant lobe-finned fishes, the lungfishes and the tetrapods. Maximum parsimony favored a lungfish/coelacanth or a lungfish/tetrapod sistergroup relationship depending on which transversion:transition weighting is assumed. Neighbor-joining and maximum likelihood supported a lungfish/tetrapod sistergroup relationship.

scholarly journals Density Management Diagram for Northeastern Red Spruce and Balsam Fir Forests

1999 ◽  
Vol 16 (1) ◽  
pp. 48-56 ◽  
Author(s):  
Duncan S. Wilson ◽  
Robert S. Seymour ◽  
Douglas A. Maguire
Keyword(s):  
Stand Density ◽  
Maximum Size ◽  
Site Index ◽  
The Self ◽  
Red Spruce ◽  
Balsam Fir ◽  
Stand Development ◽  
Exponential Relationship ◽  
Data Set ◽  
Natural Stands

Abstract A stand-density management diagram is presented for use in northeastern red spruce and balsam fir forests. The diagram was derived from an extensive archived data set collected during the 1970s from fully stocked stands throughout northern Maine and a more recent study of precommercially thinned stands. The negative exponential relationship between mean stemwood volume per tree and stand density, commonly known as the "self-thinning rule, "was formulated to define a biological maximum stand density. The maximum size-density equation can be used to calculate the relative density of any stand and is accurate for thinned and unthinned natural stands as well as plantations. Equations for estimating quadratic mean diameter and stand top height are also derived for unthinned natural stands only. Data used to fit the self-thinning line are substantially above the A-lines on the familiar northeastern stocking guides, suggesting that these guides underestimate maximum density and thus overpredict self-thinning. Examples illustrate how to use the diagram to predict stand development under commercial and precommercial thinning scenarios, as well as natural stand development without thinning. Relevant site index and volume equations are included in an appendix. North. J. Appl. For. 16(1):48-56.

scholarly journals On the abundance and source contributions of dicarboxylic acids in size-resolved aerosol particles at continental sites in central Europe

2014 ◽  
Vol 14 (8) ◽  
pp. 3913-3928 ◽  
Author(s):  
D. van Pinxteren ◽  
C. Neusüß ◽  
H. Herrmann
Keyword(s):  
Aerosol Particles ◽  
Principal Component ◽  
Large Data ◽  
Dicarboxylic Acids ◽  
Field Studies ◽  
Primary Sources ◽  
Back Trajectory ◽  
Data Set ◽  
Air Masses ◽  
Back Trajectory Analysis

Abstract. Dicarboxylic acids (DCAs) are among the most abundant organic compounds observed in atmospheric aerosol particles and have been extensively studied at many places around the world. The importance of the various primary sources and secondary formation pathways discussed in the literature is often difficult to assess from field studies, though. In the present study, a large data set of size-resolved DCA concentrations from several inland sites in Germany is combined with results from a recently developed approach of statistical back-trajectory analysis and additional data. Principal component analysis is then used to reveal the most important factors governing the abundance of DCAs in different particle size ranges. The two most important sources revealed are (i) photochemical formation during intense radiation days in polluted air masses, likely occurring in the gas phase on short timescales (gasSOA), and (ii) secondary reactions in anthropogenically influenced air masses, likely occurring in the aqueous phase on longer timescales (aqSOA). While the first source strongly impacts DCA concentrations mainly in small and large particles, the second one enhances accumulation mode DCAs and is responsible for the bulk of the observed concentrations. Primary sources were found to be minor (sea salt, soil resuspension) or non-existent (biomass burning, traffic). The results can be regarded as representative for typical central European continental conditions.

scholarly journals Applying Chemometrics to Evaluate Mine Tailings’ Potential As Partial Cement Replacement

2020 ◽  
Author(s):  
Anne Mette T. Simonsen ◽  
Kristine B. Pedersen ◽  
Pernille E. Jensen
Keyword(s):  
Mine Tailings ◽  
Principal Component ◽  
Large Data ◽  
Hierarchical Cluster ◽  
Physical Characteristics ◽  
Mine Tailing ◽  
Data Set ◽  
Cement Replacement ◽  
Partial Cement Replacement ◽  
Physical And Chemical

This study investigates the utilization of mine tailings, the by-product originating from metal- and mineral-based ore mining, as a new cement replacement material. This paper is based on the chemical and physical characteristics of 13 mine tailing samples. In this study, Chemometrics were applied to consider all parameters simultaneously and obtain a thorough screening of potential relations in the large data set. Hierarchical Cluster Analysis (HCA) groups samples according to (dis)similar features and Principal Component Analysis (PCA) visualizes predominating variables and relations to samples. The application of HCA highlighted a clear grouping between mine tailings according to characteristics. Meanwhile, PCA identified the predominant chemical and physical characteristics in the mine tailing samples. Chemometrics therefore provided a thorough overview of mine tailings’ physical and chemical characteristics. Keywords: mine tailings, chemometrics, cement replacement

scholarly journals Self-thinning dynamics in cork oak woodlands: providing a baseline for managing density

2017 ◽  
Vol 26 (1) ◽  
pp. e006 ◽  
Author(s):  
Teresa Fonseca ◽  
Luísa Monteiro ◽  
Teresa Enes ◽  
Adelaide Cerveira
Keyword(s):  
Goodness Of Fit ◽  
Quercus Suber ◽  
Cork Oak ◽  
The Self ◽  
Allometric Relationship ◽  
Oak Woodlands ◽  
Fit Statistics ◽  
Mainland Portugal ◽  
Density Relationship ◽  
Relationship Of

Aim of study: The study aims to evaluate the maximum potential stocking level in cork oak (Quercus suber L.) woodlands, using the ecologically-based size-density relationship of the self-thinning law.Area of study: The study area refers to cork oak forests in mainland Portugal, distributed along its 18 districts from north to south.Material and Methods: A dataset with a total of 2181 observations regarding pure cork oak stands was collected from the Portuguese Forest Inventory (NFI) databases and from research plots. The dataset was subjected to two filtering procedures, one more restrictive than the other, to select the stands presenting the higher stocking values. The two resulting subsets, with 116 and 36 observations, from 16 and 10 districts of mainland Portugal, respectively, were then used to assess and describe the allometric relationship between tree number and their mean diameter.Main results: The allometric relationship was analysed and modelled using the log transformed variables. A slightly curvilinear trend was identified. Thus, a straight line and a curve were both fitted for comparison purposes. Goodness-of-fit statistics point out for a good performance when the data is set to the uppermost observed stocking values. A self-thinning line for cork oak was projected from the estimated relationship.Research highlights: The self-thinning model can be used as an ecological approach to develop density guidelines for oak woodlands in a scenario of increasing cork demands. The results indicate that the recommendations being applied in Portugal are far below the maximal potential stocking values for the species. It is therefore of the utmost importance to review the traditional silvicultural guidelines and endorse new ones.

scholarly journals Metode ROBPCA (Robust Principal Component Analysis) dan Clara (Clustering Large Area) pada Data dengan Outlier

2020 ◽  
Vol 13 (2) ◽  
pp. 11
Author(s):  
Bekti Endar Susilowati ◽  
Pardomuan Robinson Sihombing
Keyword(s):  
Principal Component Analysis ◽  
Covariance Structure ◽  
Principal Component ◽  
Large Data ◽  
Component Analysis ◽  
Large Area ◽  
Robust Principal Component Analysis ◽  
Data Set ◽  
Silhouette Width ◽  
The World

Principal Component Analysis (PCA) merupakan salah satu analisis multivariat yang digunakan untuk mengganti variable dengan Principal Component yang sedikit jumlahnya namun tidak terlalu banyak informasi yang hilang. Atau dengan kata lain, it used to explain the underlying variance-covariance structure of the large data set of variables through a few linear combination of these variables. PCA sangat dipengaruhi oleh kehadiran outlier karena didasarkan pada matriks kovarian yang sensitive terhadap outlier. Oleh karena itu, pada analisis ini akan digunakan PCA yang robust terhadap outlier yaitu ROBPCA atau PCA Hubert. Selanjutnya, dari Principal Component yang terbentuk digunakan sebagai input (masukan) untuk cluster analysis dengan metode Clara (Clustering Large Area). Clustering Large Area merupakan salah satu metode k-medoids yang robust terhadap outlier dan baik digunakan pada data dalam jumlah besar. Dalam studi kasus terhadap variabel penyusun indeks kebahagiaan berdasarkan The World Happiness Report 2018 dengan metode Clara yang menggunakan jarak manhattan didapatkan nilai rata-rata Overall Average Silhouette Width yang terbaik pada 5 cluster. 

A Practical Robust and Efficient RBF Metamodel Method for Typical Engineering Problems

2008 ◽  
Author(s):  
Xingjie Fang ◽  
Liping Wang ◽  
Don Beeson ◽  
Gene Wiggs
Keyword(s):  
Principal Component ◽  
Large Data ◽  
Large Data Sets ◽  
Training Data ◽  
Data Sets ◽  
Dimensional Model ◽  
Data Set ◽  
Engineering Problems ◽  
Processing Techniques ◽  
Generalization Accuracy

Radial Basis Function (RBF) metamodels have recently attracted increased interest due to their significant advantages over other types of non-parametric metamodels. However, because of the interpolation nature of the RBF mathematics, the accuracy of the model may dramatically deteriorate if the training data set used contains duplicate information, noise or outliers. Also constructing the metamodel may be time consuming whenever the training data sets are large or a high dimensional model is required. In this paper, we propose a robust and efficient RBF metamodeling approach based on data pre-processing techniques that alleviate the accuracy and efficiency issues commonly encountered when RBF models are used in typical real engineering situations. These techniques include 1) the removal of duplicate training data information, 2) the generation of smaller uniformly distributed subsets of training data from large data sets and 3) the quantification and identification of outliers by principal component analysis (PCA) and Hotelling statistics. Simulation results are used to validate the generalization accuracy and efficiency of the proposed approach.

scholarly journals Visualization of High-Dimensional Data by Pairwise Fusion Matrices Using t-SNE

Symmetry ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 107 ◽  
Author(s):  
Mujtaba Husnain ◽  
Malik Missen ◽  
Shahzad Mumtaz ◽  
Muhammad Luqman ◽  
Mickaël Coustaty ◽  
...  
Keyword(s):  
Local Structure ◽  
High Dimensional Data ◽  
Three Dimensional ◽  
Principal Component ◽  
Large Data ◽  
High Dimensional ◽  
Data Set ◽  
Novel Approach ◽  
Critical Issues ◽  
Low Dimensional

We applied t-distributed stochastic neighbor embedding (t-SNE) to visualize Urdu handwritten numerals (or digits). The data set used consists of 28 × 28 images of handwritten Urdu numerals. The data set was created by inviting authors from different categories of native Urdu speakers. One of the challenging and critical issues for the correct visualization of Urdu numerals is shape similarity between some of the digits. This issue was resolved using t-SNE, by exploiting local and global structures of the large data set at different scales. The global structure consists of geometrical features and local structure is the pixel-based information for each class of Urdu digits. We introduce a novel approach that allows the fusion of these two independent spaces using Euclidean pairwise distances in a highly organized and principled way. The fusion matrix embedded with t-SNE helps to locate each data point in a two (or three-) dimensional map in a very different way. Furthermore, our proposed approach focuses on preserving the local structure of the high-dimensional data while mapping to a low-dimensional plane. The visualizations produced by t-SNE outperformed other classical techniques like principal component analysis (PCA) and auto-encoders (AE) on our handwritten Urdu numeral dataset.

Construction And Verification Of A Large Phylogeny Of Marsupials

2001 ◽  
Vol 23 (1) ◽  
pp. 9 ◽  
Author(s):  
FJ Lapointe ◽  
JAW Kirsch
Keyword(s):  
Large Data ◽  
Large Data Sets ◽  
Total Evidence ◽  
Data Sets ◽  
Data Set ◽  
Dna Hybridisation ◽  
Similar Information ◽  
Initial Generation ◽  
Relationship Of ◽  
Congruence Test

Much of the controversy over marsupial phylogeny at higher-categorical levels stems from the piecemeal nature of the contributing studies or the paucity of taxonomic representation in many of them. Yet the problems of constructing large phylogenies are manyfold, involving the initial generation of the data as well as their efficient analysis. Often unaddressed, also, is the need to validate extremely large data sets and trees. Many of these problems can be ameliorated by treating the data as distances (or generating distances directly). We show that, contrary to the assertions of many protagonists in the total-evidence versus consensus debate, the validated data and pathlength (tree) matrices usually give very similar results, although a few additional unstable nodes may be found when the results of internal and external validations are themselves combined in a global-congruence test. Here we illustrate our protocols with a 109-taxon data set, representing combination of marsupial DNA-hybridisation data with similar information on a series of outgroups. Phylogenetically, the results affirm the marsupial groupings we have previously found, and suggest but do not unambiguously support a nearer relationship of monotremes than placentals to marsupials. This paper represents the first attempt to validate the tree of 101 marsupials presented earlier.

THE RELATIONSHIP OF THE SPRUCE BUDWORM (CHORISTONEURA FUMIFERANA, CLEM.) TO THE FLOWERING CONDITION OF BALSAM FIR (ABIES BALSAMEA (L.) MILL.)

1952 ◽  
Vol 30 (1) ◽  
pp. 1-29 ◽  
Author(s):  
J. R. Blais
Keyword(s):  
Direct Effect ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Larval Stages ◽  
Competition For Food ◽  
Relationship Of ◽  
The Relationship

Populations of the spruce budworm were studied on flowering and nonflowering balsam fir trees. Generally more eggs were found on the flowering trees. The flowering balsam fir trees were found to harbor higher populations in the early larval stages owing to the presence on these trees of staminate flowers and flower cups. The behavior of the larvae in relation to staminate flowers and flower cups was studied in both the field and the laboratory. Larvae that fed partially on pollen developed more rapidly than larvae that fed exclusively on foliage. Pollen as a food did not appear to have any direct effect on survival or fecundity. Other experiments showed that mortality was higher, development retarded, and fecundity reduced in insects forced to feed on old foliage in contrast with those fed on the current year's growth. Defoliation was more severe on flowering trees in the earlier stages of the infestation. However, as populations increased, wandering increased owing to competition for food. This resulted in an overflow of larvae from flowering to nonflowering trees.

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