Results 1 to 10 of about 264,307 (166)

Branch rings, thinned rings, tree enveloping rings [PDF]

Israel Journal of Mathematics, 2006
We develop the theory of ``branch algebras'', which are infinite-dimensional associative algebras that are isomorphic, up to taking subrings of finite codimension, to a matrix ring over themselves. The main examples come from groups acting on trees. In particular, for every field k we construct a k-algebra K which (1) is finitely generated and infinite-
A. C. Vieira, A. G. Abercrombie, A. M. Brunner, D. G. Quillen, D. R. Farkas, D. S. Passman, D. S. Passman, G. K. Genov, G. R. Krause, I. G. Lysionok, J. Lewin, J. P. Bell, J. S. Wilson, L. Bartholdi, L. Bartholdi, L. Bartholdi, L. Bartholdi, L. Bartholdi, L. Bartholdi, L. Bartholdi, L. Bartholdi, Laurent Bartholdi, M. Abért, M. Abért, M. Lazard, N. D. Gupta, P. M. Neumann, R. I. Grigorchuk, R. I. Grigorchuk, R. I. Grigorchuk, R. I. Grigorchuk, S. A. Amitsur, S. A. Jennings, S. N. Sidki, S. N. Sidki, T. G. Ceccherini-Silberstein, T. Y. Lam, U. Vishne, V. M. Petrogradskiî, V. M. Petrogradskiî, V. M. Petrogradskiî, V. V. Nekrashevych, W. Li, Y. Barnea, Y. Lavreniuk   +44 more
openaire   +6 more sources

Statistical age determination of tree rings. [PDF]

PLoS ONE, 2020
Dendrochronology, the study of annual rings formed by trees and woody plants, has important applications in research of climate and environmental phenomena of the past.
Martin Ricker, Genaro Gutiérrez-García, David Juárez-Guerrero, Margaret E K Evans   +3 more
doaj   +2 more sources

Nonannual tree rings in a climate-sensitive Prioria copaifera chronology in the Atrato River, Colombia. [PDF]

Ecol Evol, 2017
In temperate climates, tree growth dormancy usually ensures the annual nature of tree rings, but in tropical environments, determination of annual periodicity can be more complex.
Herrera-Ramirez D, Andreu-Hayles L, Del Valle JI, Santos GM, Gonzalez PLM.   +4 more
europepmc   +3 more sources

Solar superstorm of AD 774 recorded subannually by Arctic tree rings [PDF]

Nature Communications, 2018
Tree rings retain information of sudden variations of ancient radiocarbon (14C) content, however the origin and exact timing of these events often remain uncertain.
J. Uusitalo, L. Arppe, T. Hackman, S. Helama, G. Kovaltsov, K. Mielikäinen, H. Mäkinen, P. Nöjd, V. Palonen, I. Usoskin, M. Oinonen   +10 more
doaj   +2 more sources

Superellipse Equation Describing the Geometries of Abies alba Tree Rings [PDF]

Plants
Our previous study using 41 tree rings of one Abies alba Mill. disc indicated that the superellipse equation can accurately fit its tree-ring shape. This study further used the superellipse equation (xan+yβn=1 ) to model the geometries of 1090 tree rings
Weiwei Huang, Kehang Ma, Jiaxin Tan, Meixiang Wei, Yunjie Lu   +4 more
doaj   +2 more sources

A rapid cosmic-ray increase in BC 3372-3371 from ancient buried tree rings in China. [PDF]

Nat Commun, 2017
Cosmic rays interact with the Earth's atmosphere to produce $^{14}$C, which can be absorbed by trees. Therefore, rapid increases of $^{14}$C in tree rings can be used to probe previous cosmic-ray events.
Wang FY, Yu H, Zou YC, Dai ZG, Cheng KS.
europepmc   +5 more sources

Tree demography dominates long-term growth trends inferred from tree rings. [PDF]

Glob Chang Biol, 2017
Understanding responses of forests to increasing CO2 and temperature is an important challenge, but no easy task. Tree rings are increasingly used to study such responses. In a recent study, Van der Sleen et al.
Brienen RJ, Gloor M, Ziv G.
europepmc   +3 more sources

Energetic impact of reconstructed debris flow on the intensity and duration of growth disturbances in tree rings

Frontiers in Earth Science, 2023
A rare study on the quantitative relationship between the energetic impact of debris flows on the intensity and duration of growth disturbances of tree rings was carried out, partly due to a lack of feasible approaches and detailed field evidence.
Xueliang Wang, Xueliang Wang, Xueliang Wang, Juanjuan Sun, Juanjuan Sun, Juanjuan Sun, Yong Zhang, Qisong Jiao, Shengwen Qi, Shengwen Qi, Shengwen Qi, Ran Wang, Haiyang Liu, Mengjie Zhang, Mengjie Zhang, Mengjie Zhang   +15 more
doaj   +1 more source

Olive tree-ring problematic dating: a comparative analysis on Santorini (Greece). [PDF]

PLoS ONE, 2013
Olive trees are a classic component of Mediterranean environments and some of them are known historically to be very old. In order to evaluate the possibility to use olive tree-rings for dendrochronology, we examined by various methods the reliability of
Paolo Cherubini, Turi Humbel, Hans Beeckman, Holger Gärtner, David Mannes, Charlotte Pearson, Werner Schoch, Roberto Tognetti, Simcha Lev-Yadun   +8 more
doaj   +1 more source

Synchrotron-based X-ray microscopy for assessing elements distribution and speciation in mangrove tree-rings

Results in Chemistry, 2021
Micro-X-ray fluorescence (μ-XRF) spectroscopy has been used for dendrochemistry as a high spatial resolution, multi-elemental and non-destructive technique.
Elton Eduardo Novais Alves, Daigard Ricardo Ortega Rodriguez, Pablo de Azevedo Rocha, Leonardus Vergütz, Luiz Santini Junior, Dean Hesterberg, Luiz Carlos Ruiz Pessenda, Mario Tomazello-Filho, Liovando Marciano da Costa   +8 more
doaj   +1 more source