Search results for "Geometric"
showing 10 items of 652 documents
Non-adiabatic vacuum induced berry phase
2016
We investigate quantum effects in geometric phases arising when a two-level system is interacting with a quantized electromagnetic field.
On the CAT(0) dimension of 2-dimensional Bestvina-Brady groups
2002
Let K be a 2-dimensional finite flag complex. We study the CAT(0) dimension of the `Bestvina-Brady group', or `Artin kernel', Gamma_K. We show that Gamma_K has CAT(0) dimension 3 unless K admits a piecewise Euclidean metric of non-positive curvature. We give an example to show that this implication cannot be reversed. Different choices of K lead to examples where the CAT(0) dimension is 3, and either (i) the geometric dimension is 2, or (ii) the cohomological dimension is 2 and the geometric dimension is not known.
Developing Primary School Students’ Formal Geometric Definitions Knowledge by Connecting Origami and Technology
2019
In this paper, we present opportunities with the uses of origami and technology, in our case GeoGebra, in teaching formal geometric definitions for fifth-grade primary school students (11-12yrs). Applying origami in mathematical lessons is becoming to be recognized as a valuable tool for improving students’ mathematical knowledge. In previous studies, we developed origami and technology activities for high-school mathematics, but we wanted to explore if such approach would work in primary school as well. For this reason, we chose a flat origami model оf the crane and we used this model to introduce students to basic geometrical notions and definitions, such as points, lines, intersections o…
Assouad Type Dimensions in Geometric Analysis
2021
We consider applications of the dual pair of the (upper) Assouad dimension and the lower (Assouad) dimension in analysis. We relate these notions to other dimensional conditions such as a Hausdorff content density condition and an integrability condition for the distance function. The latter condition leads to a characterization of the Muckenhoupt Ap properties of distance functions in terms of the (upper) Assouad dimension. It is also possible to give natural formulations for the validity of Hardy–Sobolev inequalities using these dual Assouad dimensions, and this helps to understand the previously observed dual nature of certain cases of these inequalities. peerReviewed
On some partial data Calderón type problems with mixed boundary conditions
2021
In this article we consider the simultaneous recovery of bulk and boundary potentials in (degenerate) elliptic equations modelling (degenerate) conducting media with inaccessible boundaries. This connects local and nonlocal Calderón type problems. We prove two main results on these type of problems: On the one hand, we derive simultaneous bulk and boundary Runge approximation results. Building on these, we deduce uniqueness for localized bulk and boundary potentials. On the other hand, we construct a family of CGO solutions associated with the corresponding equations. These allow us to deduce uniqueness results for arbitrary bounded, not necessarily localized bulk and boundary potentials. T…
Estimating the safety performance function for urban unsignalized four-legged one-way intersections in Palermo, Italy
2014
Abstract Starting from consideration that urban intersections are sites with promise for safety and operational improvements, the paper describes the steps taken to develop a crash predictive model for estimating the safety performance of urban unsignalized intersections located in Palermo, Italy. The focus is on unsignalized four-legged one-way intersections widespread in Italian downtowns. The sample considered in the study consist of 92 intersections in Palermo, Italy. For the study were collected crashes occurred in the sites during the years 2006-2012, geometric design and functional characteristics and traffic flow. Results showed that data were overdispersed and NB1 distributed. In o…
Measurement of the average shape of longitudinal profiles of cosmic-ray air showers at the Pierre Auger Observatory
2019
The profile of the longitudinal development of showers produced by ultra-high energy cosmic rays carries information related to the interaction properties of the primary particles with atmospheric nuclei. In this work, we present the first measurement of the average shower profile in traversed atmospheric depth at the Pierre Auger Observatory. The shapes of profiles are well reproduced by the Gaisser-Hillas parametrization within the range studied, for E>10 17.8 eV .A detailed analysis of the systematic uncertainties is performed using ten years of data and a full detector simulation. The average shape is quantified using two variables related to the width and asymmetry of the profile, and …
E questo dove lo metto? Esperienze geometriche in continuità tra la Scuola dell'Infanzia e la Scuola Primaria
2015
THE SCENOGRAPHY OF SERPOTTA STUCCOES REVISITED - MATERIAL AND FORM
2015
The material that lies beneath the smooth shining surface of the stuccoes of the Serpotta family who used to work in Sicily from 1670 to 1730, has been thoroughly studied in previous papers, disclosing the deep, albeit empirical, knowledge of materials science that guided the artists in creating their masterpieces. In this work, attention is focused on the solid perspective and on the scenographic sculpture by Giacomo Serpotta, who is acknowledged as the leading exponent of the School. The study deals with some particular works of the artist, the “small-scaled plastic theatres”, so-called “teatrini”, which he made for the San Lorenzo Oratory in Palermo. On the basis of archival documents an…
Ceramic Production in the Indigenous Settlement of Entella (Western Sicily) During the Archaic Age
2010
Indigenous fine tablewares (both plain and with painted geometric patterns/decorations) were widely diffused in western and central Sicily between the seventh and the fifth centuries BC (Gargini 1995; Spatafora 1996; Trombi 1999; Campisi 2003 However, the considerable recurrence of shapes and decorative subjects inhibits the identification of specific production centres merely on the basis of stylistic and morphological analyses. Therefore, the extent of the distribution of objects manufactured in different workshops cannot be fully appreciated, and the network of ceramic trade in Archaic Sicily is acknowledged only in terms of the relationships between the Phoenician and Greek colonies and…