9,263 research outputs found
On global location-domination in graphs
A dominating set of a graph is called locating-dominating, LD-set for
short, if every vertex not in is uniquely determined by the set of
neighbors of belonging to . Locating-dominating sets of minimum
cardinality are called -codes and the cardinality of an LD-code is the
location-domination number . An LD-set of a graph is global
if it is an LD-set of both and its complement . The global
location-domination number is the minimum cardinality of a
global LD-set of . In this work, we give some relations between
locating-dominating sets and the location-domination number in a graph and its
complement.Comment: 15 pages: 2 tables; 8 figures; 20 reference
The low temperature Fulde-Ferrell-Larkin-Ovchinnikov phases in 3 dimensions
We consider the nature of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phases
in three dimensions at low temperature. We introduce a new method to handle the
quasiclassical equations for superconductors with space dependent order
parameter, which makes use of a Fourier expansion. This allows us to show that,
at T=0, an order parameter given by the linear combination of three cosines
oscillating in orthogonal directions is preferred over the standard single
cosine solution. The transition from the normal state to this phase is first
order, and quite generally the transition below the tricritical point to the
FFLO phases is always first order.Comment: 4 pages, revtex, 1 figur
Extremal Graph Theory for Metric Dimension and Diameter
A set of vertices \emph{resolves} a connected graph if every vertex
is uniquely determined by its vector of distances to the vertices in . The
\emph{metric dimension} of is the minimum cardinality of a resolving set of
. Let be the set of graphs with metric dimension
and diameter . It is well-known that the minimum order of a graph in
is exactly . The first contribution of this
paper is to characterise the graphs in with order
for all values of and . Such a characterisation was
previously only known for or . The second contribution is
to determine the maximum order of a graph in for all
values of and . Only a weak upper bound was previously known
Confinement-induced resonances for a two-component ultracold atom gas in arbitrary quasi-one-dimensional traps
We solve the two-particle s-wave scattering problem for ultracold atom gases
confined in arbitrary quasi-one-dimensional trapping potentials, allowing for
two different atom species. As a consequence, the center-of-mass and relative
degrees of freedom do not factorize. We derive bound-state solutions and obtain
the general scattering solution, which exhibits several resonances in the 1D
scattering length induced by the confinement. We apply our formalism to two
experimentally relevant cases: (i) interspecies scattering in a two-species
mixture, and (ii) the two-body problem for a single species in a non-parabolic
trap.Comment: 22 pages, 3 figure
Nordhaus-Gaddum bounds for locating domination
A dominating set S of graph G is called metric-locating-dominating if it is
also locating, that is, if every vertex v is uniquely determined by its vector
of distances to the vertices in S. If moreover, every vertex v not in S is also
uniquely determined by the set of neighbors of v belonging to S, then it is
said to be locating-dominating. Locating, metric-locating-dominating and
locating-dominating sets of minimum cardinality are called b-codes, e-codes and
l-codes, respectively. A Nordhaus-Gaddum bound is a tight lower or upper bound
on the sum or product of a parameter of a graph G and its complement G. In this
paper, we present some Nordhaus-Gaddum bounds for the location number b, the
metric-location-number e and the location-domination number l. Moreover, in
each case, the graph family attaining the corresponding bound is characterized.Comment: 7 pages, 2 figure
Accretion variability of Herbig Ae/Be stars observed by X-Shooter. HD 31648 and HD 163296
This work presents X-Shooter/VLT spectra of the prototypical, isolated Herbig
Ae stars HD 31648 (MWC 480) and HD 163296 over five epochs separated by
timescales ranging from days to months. Each spectrum spans over a wide
wavelength range covering from 310 to 2475 nm. We have monitored the continuum
excess in the Balmer region of the spectra and the luminosity of twelve
ultraviolet, optical and near infrared spectral lines that are commonly used as
accretion tracers for T Tauri stars. The observed strengths of the Balmer
excesses have been reproduced from a magnetospheric accretion shock model,
providing a mean mass accretion rate of 1.11 x 10^-7 and 4.50 x 10^-7 Msun
yr^-1 for HD 31648 and HD 163296, respectively. Accretion rate variations are
observed, being more pronounced for HD 31648 (up to 0.5 dex). However, from the
comparison with previous results it is found that the accretion rate of HD
163296 has increased by more than 1 dex, on a timescale of ~ 15 years. Averaged
accretion luminosities derived from the Balmer excess are consistent with the
ones inferred from the empirical calibrations with the emission line
luminosities, indicating that those can be extrapolated to HAe stars. In spite
of that, the accretion rate variations do not generally coincide with those
estimated from the line luminosities, suggesting that the empirical
calibrations are not useful to accurately quantify accretion rate variability.Comment: 14 pages, 7 Figures, Accepted in Ap
The use of BIM technology in teaching related to Architecture: cooperative and collaborative learning based on real Projects between different subjects
In this article, it is presented the experience of the Educational Innovation Project accepted by the Basque Country University, which is being developed since 2014 at the Polytechnic University School in Donostia. This project highlights for being the first teaching experience in the Technical Architecture Degree, where teams of teachers from different subjects are developing a work in a cooperative, joint, coordinated and collaborative way, and encompassing the full spectrum of the
design - construction process closely with the architecture professional dynamics. BIM technology (Building Information Modeling) is being used so that the same three-dimensional parametric modeling is shared among different subjects, for the
resolution of real Learning Based Projects, linking teaching and labor market.En esta comunicación, se presenta la experiencia del Proyecto de Innovación Educativa aceptado por la Universidad del PaÃs Vasco, que se está desarrollando desde 2014 en la Escuela Universitaria Politécnica de Donostia. Destaca por ser la
primera experiencia docente en el Grado en Arquitectura Técnica, donde equipos docentes de diversas materias están desarrollando un trabajo de manera cooperativa, conjunta, coordinada y colaborativa, abarcando el espectro completo del proceso proyectual-constructivo en estrecha relación con la dinámica profesional Arquitectónica. Se está empleando la tecnologÃa BIM, (Building Information Modeling) de manera que se comparte un mismo modelado tridimensional paramétrico entre diferentes asignaturas, para la resolución del Aprendizaje Basado en Proyectos reales, enlazando docencia y mercado laboral
On the criticality of inferred models
Advanced inference techniques allow one to reconstruct the pattern of
interaction from high dimensional data sets. We focus here on the statistical
properties of inferred models and argue that inference procedures are likely to
yield models which are close to a phase transition. On one side, we show that
the reparameterization invariant metrics in the space of probability
distributions of these models (the Fisher Information) is directly related to
the model's susceptibility. As a result, distinguishable models tend to
accumulate close to critical points, where the susceptibility diverges in
infinite systems. On the other, this region is the one where the estimate of
inferred parameters is most stable. In order to illustrate these points, we
discuss inference of interacting point processes with application to financial
data and show that sensible choices of observation time-scales naturally yield
models which are close to criticality.Comment: 6 pages, 2 figures, version to appear in JSTA
Regularization of odd-dimensional AdS gravity: Kounterterms
As an alternative to the Dirichlet counterterms prescription, I introduce the
concept of Kounterterms as the boundary terms with explicit dependence on the
extrinsic curvature K_{ij} that regularize the AdS gravity action. Instead of a
Dirichlet boundary condition on the metric, a suitable choice of the boundary
conditions --compatible with any asymptotically AdS (AAdS) spacetime-- ensures
a finite action principle for all odd dimensions. Background-independent
conserved quantities are obtained as Noether charges associated to asymptotic
symmetries and their general expression appears naturally split in two parts.
The first one gives the correct mass and angular momentum for AAdS black
holes and vanishes identically for globally AdS spacetimes. Thus, the second
part is a covariant formula for the vacuum energy in AAdS spacetimes and
reproduces the results obtained by the Dirichlet counterterms method in a
number of cases. It is also shown that this Kounterterms series regularizes the
Euclidean action and recovers the correct black hole thermodynamics in odd
dimensions.Comment: 35+6 pages, 8 references and an appendix added, improved discussion
on boundary conditions and geometrical origin of Kounterterms. Version
accepted in JHE
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