The Progression of Sexual Relationships

The authors examine factors associated with the advancement or dissolution of newly formed sexual relationships. Data from the 2006–2010 National Survey of Family Growth (NSFG) was used to examine women and men aged 18–39 (n = 2,774) whose most recent sexual relationship began within the 12 months before their interview. Results indicate that newly formed sexual relationships are often transitory. By 12 months, only 23% of respondents remained in nonresidential sexual relationships, another 27% were cohabiting with that partner, and half had ended their relationships. Sexual relationships formed before age 25 are significantly more likely to break up than to transition into cohabitation. Indicators of social class disadvantage, such as living with a stepparent, expedited cohabitation, whereas measures of advantage, such as having a college‐educated mother, deterred transitions into shared living. Racial differences also emerge: Blacks were less likely than Whites to transition rapidly into shared living.     

MAP segmentation in Bayesian hidden Markov models: a case study

We consider the problem of estimating the maximum posterior probability (MAP) state sequence for a finite state and finite emission alphabet hidden Markov model (HMM) in the Bayesian setup, where both emission and transition matrices have Dirichlet priors. We study a training set consisting of thousands of protein alignment pairs. The training data is used to set the prior hyperparameters for Bayesian MAP segmentation. Since the Viterbi algorithm is not applicable any more, there is no simple procedure to find the MAP path, and several iterative algorithms are considered and compared. The main goal of the paper is to test the Bayesian setup against the frequentist one, where the parameters of HMM are estimated using the training data.     

THE ACADEMIC FLOW MODEL: A MARKOV-CHAIN MODEL FOR FACULTY PLANNING*

A Markov-chain faculty planning model to be used with institution-specific data is presented to describe and better understand the complex phenomena of faculty movement through an institution and on its relationship to salary costs, composition of the faculty, and faculty turnover rate. The model updates the earlier work done at Stanford University and Oregon State University by the addition of states for fixed-term appointments and for part-time FTEs to reflect accurately the current hiring trends at many institutions. The model is implemented and tested at two different institutions. The findings suggest that the model is a viable means of gaining useful insights and quantitative data on the faculty profile, salary costs, expected departures, and part-time trends. And further, when used as a planning tool, and the model apparently is comprehensive and flexible enough to analyze the probable effects, both in the short and long run, of alternative personnel policies on the faculty composition.     

On the Flexibility of Metropolis–Hastings Acceptance Probabilities in Auxiliary Variable Proposal Generation

Abstract. Use of auxiliary variables for generating proposal variables within a Metropolis–Hastings setting has been suggested in many different settings. This has in particular been of interest for simulation from complex distributions such as multimodal distributions or in transdimensional approaches. For many of these approaches, the acceptance probabilities that are used turn up somewhat magic and different proofs for their validity have been given in each case. In this article, we will present a general framework for construction of acceptance probabilities in auxiliary variable proposal generation. In addition to showing the similarities between many of the proposed algorithms in the literature, the framework also demonstrates that there is a great flexibility in how to construct acceptance probabilities. With this flexibility, alternative acceptance probabilities are suggested. Some numerical experiments are also reported.     

Generic Processes in Aligning the Multiple Bases of Identity: The Case of Becoming a Ministry Student

Identity theory distinguishes three bases of identity—role, group, and person—but studies have typically focused on one identity at a time. The interrelationship among the multiple bases of identity remains understudied. This study examines the multiple bases of identity individuals engage on their way to becoming ministry students. The results reveal the advantage of examining the multiple bases of identity as subcultural processes, the utility of qualitative research for expanding the empirical scope of identity theory, and the possibility of employing structural symbolic interactionist concepts within a processual symbolic interactionist agenda.     

Combining forecasts of electricity consumption in China with time-varying weights updated by a high-order Markov chain model

Electricity consumption forecasting has been always playing a vital role in power system management and planning. Inaccurate prediction may cause wastes of scarce energy resource or electricity shortages. However, forecasting electricity consumption has proven to be a challenging task due to various unstable factors. Especially, China is undergoing a period of economic transition, which highlights this difficulty. This paper proposes a time-varying-weight combining method, i.e. High-order Markov chain based Time-varying Weighted Average (HM-TWA) method to predict the monthly electricity consumption in China. HM-TWA first calculates the in-sample time-varying combining weights by quadratic programming for the individual forecasts. Then it predicts the out-of-sample time-varying adaptive weights through extrapolating these in-sample weights using a high-order Markov chain model. Finally, the combined forecasts can be obtained. In addition, to ensure that the sample data have the same properties as the required forecasts, a reasonable multi-step-ahead forecasting scheme is designed for HM-TWA. The out-of-sample forecasting performance evaluation shows that HM-TWA outperforms the component models and traditional combining methods, and its effectiveness is further verified by comparing it with some other existing models.     

A Bayesian approach to non-parametric monotone function estimation

Summary.  The paper proposes two Bayesian approaches to non-parametric monotone function estimation. The first approach uses a hierarchical Bayes framework and a characterization of smooth monotone functions given by Ramsay that allows unconstrained estimation. The second approach uses a Bayesian regression spline model of Smith and Kohn with a mixture distribution of constrained normal distributions as the prior for the regression coefficients to ensure the monotonicity of the resulting function estimate. The small sample properties of the two function estimators across a range of functions are provided via simulation and compared with existing methods. Asymptotic results are also given that show that Bayesian methods provide consistent function estimators for a large class of smooth functions. An example is provided involving economic demand functions that illustrates the application of the constrained regression spline estimator in the context of a multiple-regression model where two functions are constrained to be monotone.     

The Development of Peer Interaction in Infancy: Exploring the Dyadic Processes

Peer interaction is an important component of children's social repertoires that is associated with a variety of developmental outcomes and life skills. The present study provides an in‐depth study of early dyadic peer behaviors during the infancy period, during which social competence with peers is first being developed. Results from variable‐centered analyses highlight the effectiveness of behaviors, such as offering objects to peers, and point to the importance of the social context set by a peer's prior social behavior and processes for eliciting peer responses. Findings from person‐centered analyses reveal marked individual differences in the processes through which infants are successful in eliciting responses from their peers, illustrating the presence of multiple pathways to achieving social competence with peers.     

Stochastic Bounds with a Low Rank Decomposition

We investigate how we can bound a discrete time Markov chain (DTMC) by a stochastic matrix with a low rank decomposition. In the first part of the article, we show the links with previous results for matrices with a decomposition of size 1 or 2. Then we show how the complexity of the analysis for steady-state and transient distributions can be simplified when we take into account the decomposition. Finally, we show how we can obtain a monotone stochastic upper bound with a low rank decomposition.