Qualitative telephone interviews: Strategies for success

The use of the telephone in qualitative interviews is discouraged by traditionalists who view it as an inferior data collection instrument. However these claims have not been supported by empirical evidence and qualitative researchers who have used and compared the telephone to the face-to-face mode of interviewing present a different story. This study attempts to build on the limited existing research comparing the issues involved and the data collected using the telephone and face-to-face interview modes. The study evaluates the criticisms of traditionalists in the light of existing research. The study then presents the observations of the researcher based on a research project that involved 43 telephone, 1 Skype and 6 face-to-face interviews. These observations as well as the limited prior research are used to develop strategies for the effective use telephone interviews in qualitative research. The study concludes that for certain studies the telephone if used with the strategies recommended here provides qualitative researchers with a sound data collection instrument

New recurrence relationships between orthogonal polynomials which lead to new Lanczos-type algorithms

Lanczos methods for solving Ax = b consist in constructing a sequence of vectors (Xk),k = 1,... such that rk = b-AXk= Pk(A)r0, where Pk is the orthogonal polynomial of degree at most k with respect to the linear functional c defined as c(εi) = (y, Air0). Let P(1)k be the regular monic polynomial of degree k belonging to the family of formal orthogonal polynomials (FOP) with respect to c(1) defined as c(1)(εi) = c(εi+1). All Lanczos-type algorithms are characterized by the choice of one or two recurrence relationships, one for Pk and one for P(1)k. We shall study some new recurrence relations involving these two polynomials and their possible combinations to obtain new Lanczos-type algorithms. We will show that some recurrence relations exist, but cannot be used to derive Lanczos-type algorithms, while others do not exist at all

Constraints on dark energy from the Ly{\alpha} forest baryon acoustic oscillations measurement of the redshift 2.3 Hubble parameter

We use the Busca et al. (2012) measurement of the Hubble parameter at redshift z = 2.3 in conjunction with 21 lower z measurements, from Simon et al. (2005), Gaztanaga et al. (2009), Stern et al. (2010), and Moresco et al. (2012), to place constraints on model parameters of constant and time-evolving dark energy cosmological models. The inclusion of the new Busca et al. (2012) measurement results in H(z) constraints significantly more restrictive than those derived by Farooq et al. (2012). These H(z) constraints are now more restrictive than those that follow from current Type Ia supernova (SNIa) apparent magnitude measurements (Suzuki et al. 2012). The H(z) constraints by themselves require an accelerating cosmological expansion at about 2-sigma confidence level, depending on cosmological model and Hubble constant prior used in the analysis. A joint analysis of H(z), baryon acoustic oscillation peak length scale, and SNIa data favors a spatially-flat cosmological model currently dominated by a time-independent cosmological constant but does not exclude slowly-evolving dark energy density.Comment: 17 Pages, 7 Figures and 1 Table. arXiv admin note: substantial text overlap with arXiv:1211.425

Information Dissipation in Random Quantum Networks

We study the information dynamics in a network of spin-$1/2$ particles when edges representing $XY$ interactions are randomly added to a disconnected graph accordingly to a probability distribution characterized by a "weighting" parameter. In this way we model dissipation of information initially localized in single or two qubits all over the network. We then show the dependence of this phenomenon from weighting parameter and size of the network.Comment: 9 pages, 5 figure