Search results for "tree of life"
showing 10 items of 12 documents
The tree of life in the southern porch of the cathedral of Palermo: survey and geometric analysis
2016
This study focuses one of the most puzzling works of art made in Palermo at the end of the medieval age: the tree of life, a rich geometrical decoration with animal and human figures in the southern porch of the Cathedral of Palermo. Topographic and SfM photogrammetric methods produced a detailed orthophoto of the porch. Images collected during restoration have been rectified and superimposed to the orthophoto. The geometrical analysis of the decorative patterns reveals a complex design and meaningful links between the decoration and the general architectural layout of the porch.
SymbioGenomesDB: a database for the integration and access to knowledge on host-symbiont relationships.
2014
Symbiotic relationships occur naturally throughout the tree of life, either in a commensal, mutualistic or pathogenic manner. The genomes of multiple organisms involved in symbiosis are rapidly being sequenced and becoming available, especially those from the microbial world. Currently, there are numerous databases that offer information on specific organisms or models, but none offer a global understanding on relationships between organisms, their interactions and capabilities within their niche, as well as their role as part of a system, in this case, their role in symbiosis. We have developed the SymbioGenomesDB as a community database resource for laboratories which intend to investigat…
Revolutionary Struggle for Existence: Introduction to Four Intriguing Puzzles in Virus Research
2012
Cellular life is immersed into an ocean of viruses. Virosphere forms the shadow of this cell-based tree of life: completely dependent on the tree for existence, yet, the tree is equally unable to escape its ever evolving companion. How important role has the shadow played in the evolution of life? Is it a mere ethereal partner or a constitutive factor? In this chapter four puzzles in virus research are taken under the scope in order to probe some of the intriguing ways by which viruses can help us understand life on Earth. These puzzles consider the origin of genetic information in viruses, viruses as symbiotic partners, the structural diversity of viruses and the role of viruses in the ori…
L'arbre de la vie a-t-il une structure fractale?
1999
Abstract We analyse the time sequences of major evolutionary leaps at various scales, from the scale of the global tree of life, to the scales of orders and families such as sauropod dinosaurs, North American fossil Equidae, rodents, and primates including the Hominidae. In each case we find that these data are consistent with a log- periodic law to high level of statistical significance. Such a law is characterized by a critical epoch of convergence Tc specific to the lineage under consideration and that can be interpreted as the end of that lineage's capacity to evolve.
The trees in the middle of Paradise (Gn 2:9) during the Great Lent: Orthodox hymnography as biblical interpretation
2022
The article examines the interpretation of the Scripture in Byzantine hymnography during the Great Lent. Some notable recent contributions focus on Andrew of Crete’s and Romanos the Melodist’s compositions, illustrating the hymnographic way of understanding the Scriptures. The author of this study presents a selection of stanzas from hymns of the Triodion that refer to the trees of Paradise. Hymnography perceives the trees in Genesis 2–3 in direct connection with the cross. Only rarely is the tree of life a metaphor for Jesus, as the shadow of the tree of the cross is seldom a metaphor for protection. Another interesting aspect in relation to hymnography is the fact that it represents a typ…
On the Fractal Structure of Evolutionary Trees
2002
We analyse in terms of a fractal tree the time sequences of major evolutionary leaps at various scales: from the scale of the “global” tree of life (appearance of life to homeothermy), to the distinct scales of organization of clades, such as sauropod and theropod dinosaurs, North American equids, rodents, primates including hominids, and echinoderms. We also apply this type of model to the acceleration observed in the economic crisis/no-crisis pattern in Western and pre-Columbian civilizations. In each case we find that these data are consistent with a log-periodic law of acceleration or deceleration, to a high level of statistical significance. Such a law is characterized by a critical ep…
Phytophthora Root and Collar Rot of Paulownia, a New Disease for Europe
2021
Paulownia species are fast growing trees native to China, which are being grown in managed plantings in several European countries for the production of wood and biomasses. In 2018, wilting, stunting, leaf yellowing, and collapse, as a consequence of root and crown rot, were observed in around 40% of trees of a 2-year-old planting of Paulownia elongata × P. fortunei in Calabria (Southern Italy). Two species of Phytophthora were consistently recovered from roots, basal stem bark, and rhizosphere soil of symptomatic trees and were identified as Ph. nicotianae and Ph. palmivora on the basis of both morphological characteristics and phylogenetic analysis of rDNA ITS sequences. Koch’s postulates…
Convergent Evolution in Intracellular Elements: Plasmids as Model Endosymbionts
2018
Endosymbionts are organisms that live inside the cells of other species. This lifestyle is ubiquitous across the tree of life and is featured by unicellular eukaryotes, prokaryotes, and by extrachromosomal genetic elements such as plasmids. Given that all of these elements dwell in the cytoplasm of their host cell, they should be subject to similar selection pressures. Here we show that strikingly similar features have evolved in both bacterial endosymbionts and plasmids. Since host and endosymbiont are often metabolically tightly intertwined, they are difficult to disentangle experimentally. We propose that using plasmids as tractable model systems can help to solve this problem, thus allo…
L'albero della vita
2020
Le poesie sono come le foglie dell'albero della vita. Liberano da molti dèmoni esorcizzandoli in una canzone. Poems are like the leaves of the tree of life. They free you from many daemons exorcising them in a song.
Changes in group size during resource shifts reveal drivers of sociality across the tree of life
2020
ABSTRACTFrom biofilms to whale pods, organisms have repeatedly converged on sociality as a strategy to improve individual fitness. Yet, it remains challenging to identify the most important drivers—and by extension, the evolutionary mechanisms—of sociality for particular species. Here, we present a conceptual framework, literature review, and model demonstrating that the direction and magnitude of the response of group size to sudden resource shifts provides a strong indication of the underlying drivers of sociality. We catalog six functionally distinct mechanisms related to the acquisition of resources, and we model these mechanisms’ effects on the survival of individuals foraging in group…