Estimation procedures with delayed observations

The statistical model is considered in which the collection of data from several independent populations is available only at random times determined by order statistics of lifetimes of a given number of objects. Each of the populations is distributed according to a general multiparameter exponential family. The problem is to estimate the mean value vector parameter of the multiparameter exponential family of distributions of the forthcoming observations. Under the loss function involving a weighted squared error loss, the cost proportional to the events appeared and a cost of observing the process, a class of optimal sequential procedures is established. The procedures are derived in two situations: when the lifetime distribution is completely known and in the case when it is unknown but assumed to belong to an exponential subfamily with an unknown failure rate parameter.     

The Polish Social Enterprise Sector Vis-à-Vis the Welfare Regime: Following on the Solidarity Movement?

This paper presents the development of the enterprise sector and the welfare regime in Poland, dominated by two opposing trends originating from the country’s recent history: remnants of the “Communist welfare state” and liberal tendencies that came after the political and economic transformation in 1989. The growing civil society that supplements a deficient welfare system finds its roots in the peaceful underground Solidarity movement of the 1980s which played a great role in liberating Poland. After the political turnover, the Solidarity’s mission-driven approach not only survived, but also helped shape Poland’s contemporary civil society. The outlined mechanisms seem to be significant for understanding the transformation of social economy and the welfare state concept in post-communist Europe. In our paper, we identify six mechanisms underlying the Solidarity movement, which, when subsequently implemented by social entrepreneurs, has guaranteed the success of their organizations. We will also characterize the current welfare state in Poland, as well as the role of social enterprises in filling the gaps and addressing the shortcomings of the welfare state. Several case studies will illustrate the latter.     

Circadian rhythm of hot flashes and activity levels among prostate cancer patients on androgen deprivation therapy

Abstract

Background: Modifiable risk factors contribute to the pathogenesis of cardiovascular disease (CVD) and erectile dysfunction (ED). We aimed to compare the knowledge about the contribution of modifiable risk factors to the pathogenesis of CVD and ED. The impact of patients’ having modifiable risk factors on the awareness of their negative influence on the development of CVD and ED was examined.

Methods: To this multicenter cohort study, we included 417 patients with CHD who had been hospitalized in the cardiology or cardiac surgery department during the previous six weeks and underwent cardiac rehabilitation in one of the five centers. Knowledge about modifiable risk factors was collected. ED was assessed by an abridged IIEF-5 questionnaire. Comparisons between groups were conducted using the Student’s t-test, Mann–Whitney U test, and Kruskal–Wallis test. Relationships were analyzed with Spearman's rank correlation coefficient.

Results: The mean number of correctly identified risk factors for CVD was significantly higher than those for ED (3.71?±?1.87 vs. 2.00?±?1.94; p?<?.0001). Smoking was the most recognized risk factor both for CVD and ED. Dyslipidemia was least frequently identified as a risk factor for CVD. Sedentary lifestyle was the only risk factor whose incidence did not affect the level of patient knowledge.

Conclusions: Cardiac patients with ED know more about risk factors for CVD than ED. It is necessary to include information about the negative impact of modifiable risk factors on sexual health into education programs promoting healthy lifestyles in men with cardiovascular diseases.     

Traces of “I”: Concepts of Subjectivity in Polish Literature of the Last Century

This study investigates the police reports on the peasants during the early years of the New Economic Policy as the new Soviet state attempted to establish a working relationship with rural Russia through a variety of organizations, chief among these the police. As the government sought to determine the meaning of the NEP, the police in rural Russia attempted to provide the central authorities with accurate information on economic, social, and political conditions in the countryside and to establish a positive relationship with the peasantry. In the process, the police came to understand the peasantry well and demonstrated a complex appreciation of the realities of rural Russia rather than a simple proto-Stalinist worldview. Utilizing the data from the police, the Bolshevik regime in the period to Lenin’s death also demonstrated some willingness to accept a deal with the peasantry and moderate its approach—a flexibility reflected in its change from confiscation to razverstka, and again from razverstka to a single tax, and then even to modify the tax levy to reflect peasant constructs of what was “right” to pay. This flexibility emerged in large measure because the police were returning to an earlier view of the peasants as rational beings, rather than incorrigible irrational enemies.     

Prediction in trend-renewal processes for repairable systems

Some problems of point and interval prediction in a trend-renewal process (TRP) are considered. TRP’s, whose realizations depend on a renewal distribution as well as on a trend function, comprise the non-homogeneous Poisson and renewal processes and serve as useful reliability models for repairable systems. For these processes, some possible ideas and methods for constructing the predicted next failure time and the prediction interval for the next failure time are presented. A method of constructing the predictors is also presented in the case when the renewal distribution of a TRP is unknown (and consequently, the likelihood function of this process is unknown). Using the prediction methods proposed, simulations are conducted to compare the predicted times and prediction intervals for a TRP with completely unknown renewal distribution with the corresponding results for the TRP with a Weibull renewal distribution and power law type trend function. The prediction methods are also applied to some real data.     

Bias of the lse estimator of the first order autoregressive model under tukey contamination

Results of an exhaustive study of the bias of the least square estimator (LSE) of an first order autoregression coefficient α in a contaminated Gaussian model are presented. The model describes the following situation. The process is defined as X_t = α X_t-1 + Y_t . Until a specified time T, Y_t are iid normal N(0, 1). At the moment T we start our observations and since then the distribution of Y_t, t≥T, is a Tukey mixture T(εσ) = (1 – ε)N(0,1) + εN(0, σ²). Bias of LSE as a function of α and ε, and σ² is considered. A rather unexpected fact is revealed: given α and ε, the bias does not change montonically with σ (“the magnitude of the contaminant”), and similarly, given α and σ, the bias is not growing with ε (“the amount of contaminants”).     

Small-Sample Quantile Estimators in a Large Nonparametric Model

The large nonparametric model in this note is a statistical model with the family ? of all continuous and strictly increasing distribution functions. In the abundant literature of the subject, there are many proposals for nonparametric estimators that are applicable in the model. Typically the kth order statistic X _k:n is taken as a simplest estimator, with k = [nq], or k = [(n + 1)q], or k = [nq] + 1, etc. Often a linear combination of two consecutive order statistics is considered. In more sophisticated constructions, different L-statistics (e.g., Harrel–Davis, Kaigh–Lachenbruch, Bernstein, kernel estimators) are proposed. Asymptotically the estimators do not differ substantially, but if the sample size n is fixed, which is the case of our concern, differences may be serious. A unified treatment of quantile estimators in the large, nonparametric statistical model is developed.     

Public relations role in a global competition “to sell” alternative political and socio-economic models of market economy

This article extends the transitional public relations approach to international public relations research. The arguments are presented that public relations strategies and instruments were and are further on used in that competition to promote, and sometimes impose certain political and socio-economic models of market economy. The main global players, first of the United States, but most recently also China are trying to “sell” their own model not only in the former socialist/communist but also in developing countries. On the other hand, the campaign to promote European social model has just been initiated by the European Parliament.     

Isotonic estimation of the intensity of a nonhomogeneous Poisson process: The multiple realization setup

In the 1950s Brunk and Van Eeden each obtained maximum-likelihood estimators of a finite product of probability density functions under partial or complete ordering of their parameters. Their results play an important role in the general theory of inference under order restrictions and lead to an isotonic estimator of the intensity of a nonhomogeneous Poisson process. Here an elementary derivation of the maximum likelihood estimator (m.l.e.) for the intensity of a nonhomogeneous Poisson process is given when several (possibly censored) realizations are available. Boswell obtained the m.l.e. based on a single realization as well as a conditional m.l.e. under the same conditions. An example is given to show that in the multirealization setup a conditional m.l.e. may not exist; the proofs are, we believe, new and elementary. An illustrative application is given.