Forty years of doctoral public relations research in Spain: A quantitative study of dissertation contribution to theory development

In this article, doctoral dissertations on public relations written at Spanish universities (1965–2004) are examined in order to gain an understanding of the level of theory development within the discipline. The following subjects are studied: growth over time, universities where they were written, use of language, gender and the topics of doctoral dissertations. Although still in its early development, public relations doctoral research in Spain is a well-established and burgeoning field in terms of the total of theses examined (62). The conclusion, however, is that their contribution to theory building in public relations has been negligible, with the practical or operational side of public relations standing out more than the conceptual and theoretical side.     

Another impossibility result for normal form games

It is shown that the axioms Cubitt and Sugden (1994; Economic J. 104: 798) impose on a theory of rationally justifiable play (TRJP) do not prevent the possibility that two players necessarily disagree concerning the probability they ascribe to the choice of a third player. This appears to indicate that those axioms are not sufficient for defining a `reasonable' TRJP. In addition, for the case in which a player's beliefs are statistically independent, conditions for a TRJP are suggested under which the existence of a quasi-strict equilibrium is sufficient, but the existence of a consistent n-pair is not, for defining a TRJP meeting those requirements.     

Linear functional regression: The case of fixed design and functional response

The authors consider the problem of simple linear regression when the exogenous and endogenous variables are functional and the design is fixed. They propose an estimator for the underlying linear operator and prove its consistency under some conditions which ensure that the design is sufficiently informative. They consider the classical calibration (or inverse regression) problem and analyze a consistent estimator. They also give a simulation study. The proposed method is not hard to implement in practice.     

Multivariate mixtures of Erlangs for density estimation under censoring

Multivariate mixtures of Erlang distributions form a versatile, yet analytically tractable, class of distributions making them suitable for multivariate density estimation. We present a flexible and effective fitting procedure for multivariate mixtures of Erlangs, which iteratively uses the EM algorithm, by introducing a computationally efficient initialization and adjustment strategy for the shape parameter vectors. We furthermore extend the EM algorithm for multivariate mixtures of Erlangs to be able to deal with randomly censored and fixed truncated data. The effectiveness of the proposed algorithm is demonstrated on simulated as well as real data sets.     

The beta exponentiated Weibull distribution

The Weibull distribution is one of the most important distributions in reliability. For the first time, we introduce the beta exponentiated Weibull distribution which extends recent models by Lee et al. [Beta-Weibull distribution: some properties and applications to censored data, J. Mod. Appl. Statist. Meth. 6 (2007), pp. 173–186] and Barreto-Souza et al. [The beta generalized exponential distribution, J. Statist. Comput. Simul. 80 (2010), pp. 159–172]. The new distribution is an important competitive model to the Weibull, exponentiated exponential, exponentiated Weibull, beta exponential and beta Weibull distributions since it contains all these models as special cases. We demonstrate that the density of the new distribution can be expressed as a linear combination of Weibull densities. We provide the moments and two closed-form expressions for the moment-generating function. Explicit expressions are derived for the mean deviations, Bonferroni and Lorenz curves, reliability and entropies. The density of the order statistics can also be expressed as a linear combination of Weibull densities. We obtain the moments of the order statistics. The expected information matrix is derived. We define a log-beta exponentiated Weibull regression model to analyse censored data. The estimation of the parameters is approached by the method of maximum likelihood. The usefulness of the new distribution to analyse positive data is illustrated in two real data sets.     

Mixture inverse Gaussian distributions and its transformations,moments and applications

Skewed models are important and necessary when parametric analyses are carried out on data. Mixture distributions produce widely flexible models with good statistical and probabilistic properties, and the mixture inverse Gaussian (MIG) model is one of those. Transformations of the MIG model also create new parametric distributions, which are useful in diverse situations. The aim of this paper is to discuss several aspects of the MIG distribution useful for modelling positive data. We specifically discuss transformations, the derivation of moments, fitting of models, and a shape analysis of the transformations. Finally, real examples from engineering, environment, insurance, and toxicology are presented for illustrating some of the results developed here. Three of the four data sets, which have arisen from the consulting work of the authors, are new and have not been previously analysed. All these examples display that the empirical fit of the MIG distribution to the data is very good.     

Experience with an electricity market simulation tool

A successful experience to train power producers on pool-based electricity markets presented. Trainees are arranged in groups and assigned, at random, a set of generators. They play the role of power producers and compete against each other with the target of maximizing their own profits. They have to bid in terms of price and quantity to try to sell energy to the consumers through the market. The trainer plays the role of the market operator. A market simulator and a computer communication network make it possible to simulate the actual functioning of a pool-based electricity market. The simulator is based on the widely used software package MATLAB, and a computer communication net, which can be replaced by the WWW.     

Small Steps that Matter: Incremental Learning,Slack Resources and Organizational Performance

This paper examines the antecedents, consequences and moderators of incremental learning capabilities, understood as an organization's ability to gradually adapt and expand its knowledge base. Conceptualized as a dynamic capability, incremental learning is expected to be a vital driver of organizational adaptation. As dynamic capabilities consist of bundles of relatively stable routines, it is proposed that an organization's level of incremental learning capabilities will be highly persistent over time. It is also argued that building and exercising incremental learning capabilities is resource intensive and will as such tend to rely on the availability of sufficient slack resources. Last, it is suggested that incremental learning will be positively related to organizational performance, especially when the underlying business model is labour rather than capital intensive. To test these theoretical ideas, the authors draw on extensive panel data from all public non‐specialist hospitals in England and find broad support for their hypotheses.