Search results for "Sima"
showing 10 items of 248 documents
Intrecci geografici. Girolamo Cusimano: biografia di una ricerca
2020
L’idea di pubblicare un volume antologico dedicato alla produzione scientifica di Girolamo Cusimano nasce nei curatori non soltanto per rendere omaggio ad un docente universitario che ha molto contribuito a diffondere la cultura della Geografia, ma anche per dare testimonianza del ricco repertorio di conoscenze ed interessi che lo ha portato ad esplorare vari campi del sapere geografico. I saggi ospitati in questo volume, quindi, sono stati scelti con l’obiettivo di riproporre, per quanto possibile, il suo poliedrico approccio al mondo della ricerca geografica. Approccio che ha sempre felicemente coniugato teoria e prassi, conoscenza e competenza, passione e rigore scientifico. The idea of …
Seed germination and reproductive features of Lysimachia minoricensis (Primulaceae), a wild-extinct plant.
2002
Lysimachia minoricensis is one of the few Mediterranean endemic plants (Minorca, Balearic islands) that has gone extinct in the wild but which persists as extant germplasm or cultivated plants in several botanical gardens. Reproductive features (seed set, number of seeds per capsule, seed weight) and germination responses to constant temperatures, sea water and dry-heat pre-treatments were investigated to determine the extent to which they may have influenced the extinction of the species. Seed set in Lysimachia is not dependent on pollinators, suggesting a functional selfer breeding system. Most plants produced a large mean number of fruits (23.2) and seeds (466), and the mean production o…
Geografia: dialogo trE generazioni
2020
Il contributo fa parte di un volume dedicato a Girolamo Cusimano e curato dai suoi collaboratori. In esso, in particolare, si ricostruisce una parte delle vicende accademiche riguardanti Girolamo Cusimano e si presenta il lavoro "I geografi e la realtà culturale", pubblicato nel 1990 per i tipi di Flaccovio (Palermo). The contribution is part of a volume dedicated to Girolamo Cusimano and edited by his collaborators. In it, in particular, part of the academic events concerning Girolamo Cusimano are reconstructed and the work "Geographers and cultural reality", published in 1990 for the types of Flaccovio (Palermo), is presented.
Stem-injection of herbicide for control of Ailanthus altissima (Mill.) Swingle: a practical source of power for drilling holes in stems
2013
Abstract: Ailanthus altissima is a well-known invasive tree in many parts of the world showing an outstanding ability to establish within woodlands and other less-disturbed habitats. Previous studies have reported that control of this species is very difficult because of its strong resprouting. Indeed, effective control can be achieved only by mechanical treatment followed by the application of a systemic herbicide. Operating drills or saws and other mechanical equipment require electric power supply which is not readily available in many invaded sites, notably shrubslands and woodlands. In two study sites, we evaluated control obtained by glyphosate through a stem-injection technique and c…
Metric Lie groups admitting dilations
2019
We consider left-invariant distances $d$ on a Lie group $G$ with the property that there exists a multiplicative one-parameter group of Lie automorphisms $(0, \infty)\rightarrow\mathtt{Aut}(G)$, $\lambda\mapsto\delta_\lambda$, so that $ d(\delta_\lambda x,\delta_\lambda y) = \lambda d(x,y)$, for all $x,y\in G$ and all $\lambda>0$. First, we show that all such distances are admissible, that is, they induce the manifold topology. Second, we characterize multiplicative one-parameter groups of Lie automorphisms that are dilations for some left-invariant distance in terms of algebraic properties of their infinitesimal generator. Third, we show that an admissible left-invariant distance on a Lie …
«Nolite extollere in altum cornu vestrum». Ipotesi sul campanile della chiesa della Santissima Annunziata di Messina
2022
This article addresses a series of hypothesis concerning the octagonal space indicated in Guarino Guarini’s drawings of the Church of the Santissima Annunziata in Messina in his Architettura Civile. The façade of the church was completed around 1660 by Guarino Guarini and presented a «prodigiously high» bell tower at the corner, which collapsed during the 1693 earthquake and was later rebuilt shorter. The entire church was destroyed during the 1908 earthquake. Guarini’s drawings published in his treatise suggest that there must have been an octagonal chapel with columns at the corners under the tower; perhaps it was the baptistery of the church. Alternatively, the octagon can be identified …
Topics on n-ary algebras
2011
We describe the basic properties of two n-ary algebras, the Generalized Lie Algebras (GLAs) and, particularly, the Filippov (or n-Lie) algebras (FAs), and comment on their n-ary Poisson counterparts, the Generalized Poisson (GP) and Nambu-Poisson (N-P) structures. We describe the Filippov algebra cohomology relevant for the central extensions and infinitesimal deformations of FAs. It is seen that semisimple FAs do not admit central extensions and, moreover, that they are rigid. This extends the familiar Whitehead's lemma to all $n\geq 2$ FAs, n=2 being the standard Lie algebra case. When the n-bracket of the FAs is no longer required to be fully skewsymmetric one is led to the n-Leibniz (or…
Quantum groups and deformed special relativity
1994
The structure and properties of possible $q$-Minkowski spaces is discussed, and the corresponding non-commutative differential calculi are developed in detail and compared with already existing proposals. This is done by stressing its covariance properties as described by appropriate reflection equations. Some isomorphisms among the space-time and derivative algebras are demonstrated, and their representations are described briefly. Finally, some physical consequences and open problems are discussed.
Václav Hlavatý on intuition in Riemannian space
2019
Abstract We present a historical commentary together with an English translation of a mathematical-philosophical paper by the Czech differential geometer and later proponent of a geometrized unified field theory Vaclav Hlavatý (1894–1969). The paper was published in 1924 at the height of interpretational debates about recent advancements in differential geometry triggered by the advent of Einstein's general theory of relativity. In the paper he argued against a naive generalization of analogical reasoning valid for curves and surfaces in three-dimensional Euclidean space to the case of higher-dimensional curved Riemannian spaces. Instead, he claimed, the only secure ground to arrive at resu…
Generalized Camassa-Holm Equations: Symmetry, Conservation Laws and Regular Pulse and Front Solutions
2021
In this paper, we consider a member of an integrable family of generalized Camassa–Holm (GCH) equations. We make an analysis of the point Lie symmetries of these equations by using the Lie method of infinitesimals. We derive nonclassical symmetries and we find new symmetries via the nonclassical method, which cannot be obtained by Lie symmetry method. We employ the multiplier method to construct conservation laws for this family of GCH equations. Using the conservation laws of the underlying equation, double reduction is also constructed. Finally, we investigate traveling waves of the GCH equations. We derive convergent series solutions both for the homoclinic and heteroclinic orbits of the…