Bayesian inference for dynamic social network data

We consider a continuous-time model for the evolution of social networks. A social network is here conceived as a (di-) graph on a set of vertices, representing actors, and the changes of interest are creation and disappearance over time of (arcs) edges in the graph. Hence we model a collection of random edge indicators that are not, in general, independent. We explicitly model the interdependencies between edge indicators that arise from interaction between social entities. A Markov chain is defined in terms of an embedded chain with holding times and transition probabilities. Data are observed at fixed points in time and hence we are not able to observe the embedded chain directly. Introducing a prior distribution for the parameters we may implement an MCMC algorithm for exploring the posterior distribution of the parameters by simulating the evolution of the embedded process between observations.     

NOTE ON POINT AND INTERVAL ESTIMATION AND PREDICTION FOR NORMAL EQUICORRELATED DATA

For normal homoscedastic equicorrelated data the parameters μ, σ and p are identifiable, but it is shown that no consistent estimators exist. Confidence intervals for μ and prediction intervals with known confidence coefficients can, however, be obtained.     

WHO'S PUBLISHING IN JMFT? AN EXAMINATION OF AUTHOR CHARACTERISTICS

This article examines the gender, setting, and degree of the first authors of published articles in JMFT from 1990 to 1995. Findings reveal that men are the first authors of 67% of the articles and women, 33%. PhDs are first authors on 58% of the articles, and authors in university settings write 53% of the published articles. Thirty-nine percent of the articles published during this period were research; 26%, clinical; 16%, theory; and 14%, training. Surprising findings were that MSW authors had a higher acceptance rate than PhDs, and authors in training institutes had a higher acceptance rate than those in university settings.     

Beliefs and practices resulting in female deaths and fewer females than males in India

A preference for sons and the low status of females are implicated in the preponderance of males over females as reported in each census of India from the first one taken in the 19th century. A number of cultural practices, some of which are quite ancient, are involved in this sexual imbalance, namely, maternal mortality due to unhygienic lying-in and postpartum conditions and practices, female infanticide, female feticide, Sati, murder, dowry murder, and suicide. This discussion is based both on 19th and 20th century sources and on fieldwork conducted in the North Indian village of Shanti Nagar in 1958–59 and 1977–78. These practices are most prominent in Punjab, Uttar Pradesh, Maharashtra, Gujarat, and the Union Territory of Delhi. Initially the British tended to overlook some of them, but in the early 19th century and thereafter the British Raj passed laws to curb, especially, female infanticide and Sati. The modern Government of India has also sought to abolish dowry which would, presumably, put an end to dowry murder. Moreover, the Government has issued three circulars directing that action be taken under the penal code against anyone using a prenatal sex-determination test with the object of abortion—a directive aimed at stopping female feticide. Again with the intent of curbing female feticide, a bill providing for punishment and heavy fines for doctors violating the ban on sex-determination tests has recently been introduced in the state legislature of Maharashtra. Despite these efforts, most of the beliefs and practices here described have proved to be tenacious.     

The Evolution of Organizations: Suggestions from Complexity Theory About the Interplay Between Natural Selection and Adaptation

There has been much debate in the managementliterature between neo-Darwinists (who believe in thenatural selection of populations of organizations) andadaptationists (who contend that changes in organization structure and behavior occur in response to theenvironment). The general thesis of neo-Darwinism isthat species are blindly selected for survival by theenvironment. The latest empirical support for the dominant neo-Darwinism perspective adopted bymost biologists is based primarily on the experimentsconducted by Salvador Luria who claims to haveconclusively demonstrated that genes mutate randomly.Recently, however, biologists have re-examined Luria sresearch methods and, after replications of hisexperiments, now question some aspects of the validityof his results. Moreover, there is now new researchwhich provides support for the earlier adaptationistposition, namely, the existence of evolutionary driversand directors existing within self-organizing systems.Of particular importance to the present study is the experimental indication thatself-organizing systems play a conscious role in theirown evolution. We propose that similar mechanisms orprocesses operate in organizational adaptation, thuspointing toward a theoretical modification ofneo-Darwinism that embraces both adaptation and naturalselection in a general, unified theory.     

Changes in Income Concentration: Taxes or Macroeconomic Conditions?

We examine the relative importance of tax rates and macroeconomic fluctuations in explaining the share of national adjusted gross income (AGI) reported by the top 0.5% of all taxpayers. Results indicate that cutting the top income or capital gains tax rate would increase the top AGI share but not by enough to increase revenues. The preponderance of evidence suggests that the top AGI share is affected more by the capital gains tax rate than by the income tax rate but that real gross domestic product fluctuations have even larger effects.     

Estimation of regression models with equi-correlated responses when some observations on the response variable are missing

The present article deals with the problem of estimation of parameters in a linear regression model when some data on response variable is missing and the responses are equi-correlated. The ordinary least squares and optimal homogeneous predictors are employed to find the imputed values of missing observations. Their efficiency properties are analyzed using the small disturbances asymptotic theory. The estimation of regression coefficients using these imputed values is also considered and a comparison of estimators is presented.     

Easy-to-construct confidence bands for comparing two simple linear regression lines

This paper shows how to construct confidence bands for the difference between two simple linear regression lines. These confidence bands provide directly the information on the magnitude of the difference between the regression lines over an interval of interest and, as a by-product, can be used as a formal test of the difference between the two regression lines. Various different shapes of confidence bands are illustrated, and particular attention is paid towards confidence bands whose construction only involves critical points from standard distributions so that they are consequently easy to construct.