Search results for "elementary"
showing 10 items of 863 documents
Evidence for a Particle Produced in Association with Weak Bosons and Decaying to a Bottom-Antibottom Quark Pair in Higgs Boson Searches at the Tevatr…
2012
Aaltonen, T. et al.
Algorithms for Computing Abelian Periods of Words
2012
Constantinescu and Ilie (Bulletin EATCS 89, 167--170, 2006) introduced the notion of an \emph{Abelian period} of a word. A word of length $n$ over an alphabet of size $\sigma$ can have $\Theta(n^{2})$ distinct Abelian periods. The Brute-Force algorithm computes all the Abelian periods of a word in time $O(n^2 \times \sigma)$ using $O(n \times \sigma)$ space. We present an off-line algorithm based on a $\sel$ function having the same worst-case theoretical complexity as the Brute-Force one, but outperforming it in practice. We then present on-line algorithms that also enable to compute all the Abelian periods of all the prefixes of $w$.
A note on easy and efficient computation of full abelian periods of a word
2016
Constantinescu and Ilie (Bulletin of the EATCS 89, 167-170, 2006) introduced the idea of an Abelian period with head and tail of a finite word. An Abelian period is called full if both the head and the tail are empty. We present a simple and easy-to-implement $O(n\log\log n)$-time algorithm for computing all the full Abelian periods of a word of length $n$ over a constant-size alphabet. Experiments show that our algorithm significantly outperforms the $O(n)$ algorithm proposed by Kociumaka et al. (Proc. of STACS, 245-256, 2013) for the same problem.
Fast computation of abelian runs
2016
Given a word $w$ and a Parikh vector $\mathcal{P}$, an abelian run of period $\mathcal{P}$ in $w$ is a maximal occurrence of a substring of $w$ having abelian period $\mathcal{P}$. Our main result is an online algorithm that, given a word $w$ of length $n$ over an alphabet of cardinality $\sigma$ and a Parikh vector $\mathcal{P}$, returns all the abelian runs of period $\mathcal{P}$ in $w$ in time $O(n)$ and space $O(\sigma+p)$, where $p$ is the norm of $\mathcal{P}$, i.e., the sum of its components. We also present an online algorithm that computes all the abelian runs with periods of norm $p$ in $w$ in time $O(np)$, for any given norm $p$. Finally, we give an $O(n^2)$-time offline randomi…
Gradings on the algebra of upper triangular matrices and their graded identities
2004
Abstract Let K be an infinite field and let UT n ( K ) denote the algebra of n × n upper triangular matrices over K . We describe all elementary gradings on this algebra. Further we describe the generators of the ideals of graded polynomial identities of UT n ( K ) and we produce linear bases of the corresponding relatively free graded algebras. We prove that one can distinguish the elementary gradings by their graded identities. We describe bases of the graded polynomial identities in several “typical” cases. Although in these cases we consider elementary gradings by cyclic groups, the same methods serve for elementary gradings by any finite group.
Precision Determination of Cyclotron Frequencies of Free Electrons and Ions
1982
Within the last two decades the electrodynamical storage of electrons and ions developed into an experimental method of great versatility. That this method is now being used in so many different fields of physics and chemistry results primarily from the long storage times which nowadays can be achieved. Under ultrahigh vacuum conditions and in sufficiently strong electromagnetic fields the particles can easily be trapped for hours or even days. This really long storage time offers the possibility of studying reactions of very slow rate to the chemist and of precision measurement of photon-ion interactions to the physicist. The accuracy of photon-ion interaction measurement is finally limite…
Diagrammatic expansion for positive density-response spectra: Application to the electron gas
2015
In a recent paper [Phys. Rev. B 90, 115134 (2014)] we put forward a diagrammatic expansion for the self-energy which guarantees the positivity of the spectral function. In this work we extend the theory to the density response function. We write the generic diagram for the density-response spectrum as the sum of partitions. In a partition the original diagram is evaluated using time-ordered Green's functions (GF) on the left-half of the diagram, antitime-ordered GF on the right-half of the diagram and lesser or greater GF gluing the two halves. As there exist more than one way to cut a diagram in two halves, to every diagram corresponds more than one partition. We recognize that the most co…
Study of elementary reactions with the hades dielectron spectrometer
2010
Results obtained with the HADES dielectron spectrometer at GSI are discussed, with emphasis on dilepton production in elementary reactions. Díaz Medina, José, Jose.Diaz@uv.es ; Gil Ortiz, Alejandro, Alejandro.Gil@ific.uv.es
Investigating elementary school students’ text-based argumentation with multiple online information resources
2020
In this study, we explored how elementary school students used multiple information resources in responding to a text-based argumentation task asking them to research a set of online texts in order to state and justify their stance on a controversial health-related issue. Results showed that most students took a stance that was consistent with the majority of the information resources that they read, that they mainly drew on more reliable resources in their written task products, and that they justified their stance by providing one or more supporting reasons. Students relied much more on copying and paraphrasing content from the online resources than on integrating information within and a…
Competency Profile of the Elementary School Teacher : analysis of Pre-service Elementary School Teacher's Opinion
2014
ResumenEl objeto del presente estudio se centra en conocer la opinión del alumnado de la primera promoción del Grado en Educación Primaria de la Universidad de La Rioja (n=105) sobre las competencias que configuran el perfil del docente, con el fin de contrastarla con los resultados que nos brinda la investigación y esbozar propuestas para la formación de los futuros maestros. Para tal fin se diseña y administra un autoinforme integrado por diferentes atributos presentados en un formato de respuesta de tipo Likert. Los resultados han derivado en dos escalas; la primera determina el ser del docente y se agrupa en competencias para saber hacer y en competencias afectivo-emocionales; la segund…