Dominating sets and ego-centered decompositions in social networks

Our aim here is to address the problem of decomposing a whole network into a minimal number of ego-centered subnetworks. For this purpose, the network egos are picked out as the members of a minimum dominating set of the network. However, to find such an efficient dominating ego-centered construction, we need to be able to detect all the minimum dominating sets and to compare all the corresponding dominating ego-centered decompositions of the network. To find all the minimum dominating sets of the network, we are developing a computational heuristic, which is based on the partition of the set of nodes of a graph into three subsets, the always dominant vertices, the possible dominant vertices and the never dominant vertices, when the domination number of the network is known. To compare the ensuing dominating ego-centered decompositions of the network, we are introducing a number of structural measures that count the number of nodes and links inside and across the ego-centered subnetworks. Furthermore, we are applying the techniques of graph domination and ego=centered decomposition for six empirical social networks.Comment: 17 pages, 7 figure

Gamma-soft Analog of the Confined Beta-soft Rotor Model

A gamma-soft analog of the confined beta-soft (CBS) rotor model is developed, by using a gamma-independent displaced infinite well beta-potential in the Bohr Hamiltonian, for which exact separation of variables is possible. Level schemes interpolating between the E(5) critical point symmetry (with R(4/2)=E(4)/E(2)= 2.20) and the O(5) gamma-soft rotor (with R(4/2)=2.50) are obtained, exhibiting a crossover of excited 0+ bandheads which leads to agreement with the general trends of first excited 0+ states in this region and is observed experimentally in 128-Xe and 130-Xe.Comment: 10 pages, LaTeX, including 7 eps figure

IT\u27S ALL ABOUT BALANCE: PROPENSITY SCORE MATCHING IN THE CONTEXT OF COMPLEX SURVEY DATA

Many research studies aim to draw causal inferences using data from large, nationally representative survey samples, and many of these studies use propensity score matching to make those causal inferences as rigorous as possible given the non-experimental nature of the data. However, very few applied studies are careful about incorporating the survey design with the propensity score analysis, which may mean that the results don’t generate population inferences. This may be because few methodological studies examine how to best combine these methods. Furthermore, even fewer of the methodological studies incorporate different non-response mechanisms in their analysis. This study examines methods for how to handle survey weights in propensity score matching analyses of survey data, under diferent non-response mechanisms. Based on the results from Monte Carlo simulations implemented on synthetic data as well as a data based application we developed suggestions regarding the implementation of propensity score methods to make causal inferences relevant to the target population of a sample survey. Our main conclusions are: (1) whether the survey weights are incorporated in the estimation of the propensity score does not impact estimation of the population treatment effect, as long as good population balance is achieved across confounders, (2) survey weights must be taken into account in the outcome analysis and (3) transfer of survey weights (i.e., matched comparison units are assigned the sampling weight of the treated unit they have been matched to) can be benefcial under certain non-response mechanisms

Two-zero textures for Dirac Neutrinos

We review the two-zero mass matrix textures approach for Dirac neutrinos with the most recent global fit in the oscillation parameters. We found that three of the 15 possible textures are compatible with current experimental data, while the remaining two-zero textures are ruled out. Two textures are consistent with the neutrino masses' normal hierarchy and are CP-conserving. At the same time, the other one is compatible with both mass orderings and allows for CP violation. We also present the correlations between the oscillation parameters for the allowed two-zero textures.Comment: 8 pages, 4 figure

Cultivo de una comunidad de práctica que promueva hábitos de respeto, buen uso y cuidado del agua en la localidad de Creel, Chihuahua

El presente trabajo muestra la forma en que una comunidad de práctica puede ser utilizada como un recurso eficaz para dar respuesta a necesidades de gestión del conocimiento y del aprendizaje, mediante acciones colectivas en entornos donde las estructuras tradicionales de trabajo no dan respuesta a los retos planteados. Esta propuesta surge desde un organismo descentralizado del gobierno estatal que busca involucrar a diferentes actores para mejorar la relación que tenemos con el agua

Analytic Description of Critical Point Actinides in a Transition from Octupole Deformation to Octupole Vibrations

An analytic collective model in which the relative presence of the quadrupole and octupole deformations is determined by a parameter (phi_0), while axial symmetry is obeyed, is developed. The model [to be called the analytic quadrupole octupole axially symmetric model (AQOA)] involves an infinite well potential, provides predictions for energy and B(EL) ratios which depend only on phi_0, draws the border between the regions of octupole deformation and octupole vibrations in an essentially parameter-independent way, and describes well 226-Th and 226-Ra, for which experimental energy data are shown to suggest that they lie close to this border. The similarity of the AQOA results with phi_0=45 degrees for ground state band spectra and B(E2) transition rates to the predictions of the X(5) model is pointed out. Analytic solutions are also obtained for Davidson potentials, leading to the AQOA spectrum through a variational procedure.Comment: LaTeX, 27 pages, including 14 postscript figure