Results 1 to 10 of about 265,624 (295)
Branch Rings, Thinned Rings, Tree Enveloping Rings [PDF]
Israel Journal of Mathematics, 2005 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
A. C. Vieira +44 more
core +5 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 +3 more
doaj +2 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 +10 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 +4 more
europepmc +3 more sources
Superellipse Equation Describing the Geometries of Abies alba Tree Rings [PDF]
PlantsOur 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 +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
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 +15 more
doaj +1 more source
Trees and valuation rings [PDF]
Transactions of the American Mathematical Society, 2000 Let \(D\) be a division algebra, finite dimensional over its centre \(F\). The set \(B\) of valuation rings (not necessarily invariant) in \(D\), regarded as a graph, forms a rooted tree (with the maximal element \(D\) as root). The authors ask whether every finite rooted tree can be realized in this way.
Brungs, Hans, Gräter, Joachim
openaire +3 more sources
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 +8 more
doaj +1 more source
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 +8 more
doaj +1 more source