Search results for "Arity"
showing 10 items of 2893 documents
Dynamical susceptibility from simulations of a mean field Potts glass
2004
Abstract We present results of the non-linear dynamic susceptibility χ(t) in a mean field Potts glass from simulations in a wide range of temperatures above the theoretically predicted dynamical transition, for various system sizes up to 2560 spins. χ(t) has a maximum, with a height that diverges like (T−TD)−α, with α≈1. The timescale t ∗ associated with this maximum also approaches a singularity, and we show that its behavior is compatible with the relaxation time of the standard time-dependent spin autocorrelation function, also with respect to finite size effects. We find that χ(t) for temperatures near the transition temperature TD satisfies a dynamical scaling property.
Anisotropy-Induced Effects in the Dynamics of an Ion Confined in a Two-Dimensional Paul Trap
2006
We investigate the role of anisotropy in the dynamics of a single trapped ion interacting with two orthogonal laser beams, considering how it modifies a scheme for the generation of Schrödinger cat states and the so called parity effect in two-dimensional isotropic Paul traps. We find that anisotropy gives rise to a richer class for the generated states and to a larger number of observables sensitive to the parity of the number of excitation of the vibrational motion of the ion.
Quadratic ${\mathcal P}{\mathcal T}$-symmetric operators with real spectrum and similarity to self-adjoint operators
2012
It is established that a -symmetric elliptic quadratic differential operator with real spectrum is similar to a self-adjoint operator precisely when the associated fundamental matrix has no Jordan blocks.This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Quantum physics with non-Hermitian operators’.
The Power of Word-Frequency Based Alignment-Free Functions: a Comprehensive Large-Scale Experimental Analysis
2021
Abstract Motivation Alignment-free (AF) distance/similarity functions are a key tool for sequence analysis. Experimental studies on real datasets abound and, to some extent, there are also studies regarding their control of false positive rate (Type I error). However, assessment of their power, i.e. their ability to identify true similarity, has been limited to some members of the D2 family. The corresponding experimental studies have concentrated on short sequences, a scenario no longer adequate for current applications, where sequence lengths may vary considerably. Such a State of the Art is methodologically problematic, since information regarding a key feature such as power is either mi…
Overlap and diversity in antimicrobial peptide databases: Compiling a non-redundant set of sequences
2015
Abstract Motivation: The large variety of antimicrobial peptide (AMP) databases developed to date are characterized by a substantial overlap of data and similarity of sequences. Our goals are to analyze the levels of redundancy for all available AMP databases and use this information to build a new non-redundant sequence database. For this purpose, a new software tool is introduced. Results: A comparative study of 25 AMP databases reveals the overlap and diversity among them and the internal diversity within each database. The overlap analysis shows that only one database (Peptaibol) contains exclusive data, not present in any other, whereas all sequences in the LAMP_Patent database are inc…
Integrable Hamiltonian systems with swallowtails
2010
International audience; We consider two-degree-of-freedom integrable Hamiltonian systems with bifurcation diagrams containing swallowtail structures. The global properties of the action coordinates in such systems together with the parallel transport of the period lattice and corresponding quantum cells in the joint spectrum are described in detail. The relation to the concept of bidromy which was introduced in Sadovski´ı and Zhilinski´ı (2007 Ann. Phys. 322 164–200) is discussed.
A segmented regression model for event history data: an application to the fertility patterns in Italy
2009
We propose a segmented discrete-time model for the analysis of event history data in demographic research. Through a unified regression framework, the model provides estimates of the effects of explanatory variables and jointly accommodates flexibly non-proportional differences via segmented relationships. The main appeal relies on ready availability of parameters, changepoints, and slopes, which may provide meaningful and intuitive information on the topic. Furthermore, specific linear constraints on the slopes may also be set to investigate particular patterns. We investigate the intervals between cohabitation and first childbirth and from first to second childbirth using individual data …
Enseñanza de Estadística en un contexto multidisciplinar: una experimentación en un instituto italiano
2019
III Congreso Internacional Virtual de Educación Estadística (CIVEEST), 21-24 febrero de 2019. [www.ugr.es/local/fqm126/civeest.html] This paper describes an experiment performed at a Vocational School in Palermo during the school year 2010-11. It was designed to teach Statistics at the Secondary level following a multidisciplinary approach. The didactic activity involved the mathematics, Italian, English language and science teachers. We adapted materials and methods from the M@t.abel E-learning program, which is planned for learning basic mathematics in a middle school, in order to use it for experimentation at a professional school. The assessment of the experimentation is based on teache…
Barriers to rotation in ortho-substituted tertiary aromatic amides: Effect of chloro-substitution on resonance and distortion
2018
Planarity of the amide bond represents one of the most widely recognized properties of amides. Herein, we report a combined structural and computational study on the effect of ortho-substitution on resonance and barriers to rotation in tertiary aromatic amides. We demonstrate that ortho-chloro substitution in a class of benzamides that are important from the reactivity and medicinal chemistry perspective results in increased barriers to rotation around both the N-C(O) and C-C(O) axes. The effect of steric hindrance on structures, resonance energies, barriers to rotation, and proton affinities is discussed. The present study strongly supports the use of ortho-substitution in common benzamide…
Synthesis and structural characterisation of bulky heptaaromatic (hetero)aryl o-substituted s-aryltetrazines
2020
An expedient two-step synthesis produces in good yield polyaromatic heptacyclic (hetero)arylated o-substituted s-aryltetrazines (s-Tz) directly from diphenyl s-tetrazine. This methodology overcomes the steric limitations of classical Pinner-like syntheses encountered for o-functionalized s-Tz. A single step palladium-catalyzed N-directed C–H bond tetrahalogenation is followed by a Pd-catalyzed Suzuki (hetero)arylation that is achieved simultaneously on four sites. The single crystal X-ray diffraction structure of the resulting typical polyaromatic heptacyclic aromatic compound 3,6-bis(2,6-diphenyl)-1,2,4,5-tetrazine (3) is analyzed, together with R-functionalized peripheral phenyl derivativ…