In this paper X-ray computed tomography imaging data is used to perform nondestructive tree-ring width measurements in three archaeological wooden samples. Measurements of the curvilinear-tree-ring widths are performed using two approaches: firstly, measuring manually distance between points on consecutive tree-rings along orthogonal radii and, secondly, a recently proposed computational approa...

The Bohemian Forest was exposed to high levels of sulfur and nitrogen deposition during the last century. The change in acid deposition caused a rapid decline in pH and increase in Al concentrations of soil solutions since the 1950s. A possible negative effect of soil chemistry on growth of Norway spruce tree has been studied using the 13C isotopic signal and chemistry of the tree rings. Tree r...

In dendrochronology wood samples are dated according to the tree rings they contain. The dating process consists of comparing the sequence of tree ring widths in the sample to a dated master sequence. Assuming that a tree forms exactly one ring per year a simple sliding algorithm solves this matching task. But sometimes a tree produces no ring or even two rings in a year. If a sample sequence c...

In the present study, the high-resolution stable carbon ( 13 C/ 12 C) and oxygen ( 18 O/ 16 O) isotope ratio profiles in the wood of the mangrove Rhizophora mucronata Lam., a tropical tree species lacking distinct growth rings, were investigated. Variations of both isotope ratios revealed a remarkable annual cyclicity with lowest values occurring at the latewood/earlywood boundary (April–May) a...

In this paper pivoting M-tree (PM-tree) is introduced, a metric access method combining M-tree with the pivot-based approach. While in M-tree a metric region is represented by a hyper-sphere, in PMtree the shape of a metric region is determined as an intersection of the hyper-sphere and a set of hyper-rings. The set of hyper-rings for each metric region is related to a fixed set of pivot object...

the paper deals with the analysis of the external factor (solar activity, volcanic eruptions) influence on tree growth at the kola peninsula, northwestern russia. pinus sylvestris l. (scots pine) tree-ring chronologies collected nearby the northern timberline (68.63n, 33.25e) include the oldest (1445-2005 ad) living pine tree found up to date in the kola peninsula. a total of 18 living trees p...

we show  that a projective maximal submodule of afinitely generated, regular, extending module is a directsummand. hence, every finitely generated, regular, extendingmodule with projective maximal submodules is semisimple. as aconsequence, we observe that every regular, hereditary, extendingmodule is semisimple. this generalizes and simplifies a result of  dung and   smith. as another consequen...