Estimation of General Stationary Processes by Variable Length Markov Chains

We develop new results about a sieve methodology for the estimation of minimal state spaces and probability laws in the class of stationary processes defined on finite categorical spaces. Using a sieve approximation with variable length Markov chains of increasing order, we show that an adapted version of the Context algorithm yields asymptotically correct estimates for the minimal state space and for the underlying probability distribution. As a side product, the method of sieves yields a nice graphical tree representation for the potentially infinite dimensional minimal state space of the data generating process, which is very useful for exploration of the memory.     

Effects of a self-efficacy intervention on initiation of recommended exercises in patients with spondylosis

An intervention designed to enhance preaction self-efficacy beliefs (i.e., beliefs about ability to initiate behavior despite anticipated barriers during the initiation period) was tested in patients with spondylosis in relation to initiation of exercises recommended by a consultant in orthopedic rehabilitation. Sixty patients (age 28-83 years; 44% men) with spondylosis who had not previously performed exercises recommended for degenerative spine diseases were randomly assigned to a control (education session) or intervention group. Three weeks later, intervention patients performed recommended exercises more frequently than controls. Regression analysis for all patients showed that preintervention, preaction self-efficacy predicted exercise. Age and preintervention self-efficacy moderated the intervention effects. Among older patients, only those with weak preintervention, preaction self-efficacy beliefs benefited from the intervention, whereas among younger patients, only those with strong preintervention, preaction self-efficacy beliefs benefited from the intervention.     

Social Problems,by Amitai Etzioni. Foundations of Modern Sociology Series. Prentice Hall,Englewood Cliffs,New Jersey, 1976. $3.95, Paper. 182 Pp.

Abstract

Publication productivity has received increasing attention in the social work literature. A major shortcoming of the social work literature on productivity is the paucity of attention given specifically to the publication efforts of ethnic minority social work educators. This article presents findings from the first national survey to specifically focus on publication productivity among African-American social work faculty. The data generated from the survey reveal that productivity is associated more with individual-level factors than structural factors, a minority of African-American faculty are producing most of the publications, and African-American social work faculty are producing slightly fewer publications than the broader population of social work faculty.     

Literature as the Guide to History

The author presents a content integration that focuses on social studies and science knowledge and skills. The idea of using folk crafts to help elementary students learn social studies extends from John Dewey's laboratory school to the twenty-first century. Meaningful content is applied to skills, such as blacksmithing, found in the community, and students make connections between school knowledge and their lives outside of school. In this activity, blacksmithing helped students integrate ideas from multiple academic subjects, incorporating content from the social sciences and humanities. The guest content expert with a specialized knowledge base played a large role in making this experience occur for the students and teachers.     

Self‐Reported Likelihood of Whistleblowing by Social Work Students

This article presents a first study on the professional–ethical dilemma of whistleblowing in social work, and suggests some lines for further research on this topic as well as ways for integrating it in the social work curriculum. The study examines the self‐reported readiness of social work students to blow the whistle, whether internally or externally. Internal disclosure entails reporting the wrongdoing to an authority within the organization. External disclosure entails reporting the offense to an outside agency, such as the police, professional organization, or press. The findings indicate that the students view the acts that are detrimental or cause injustice to the client in a very serious light. In dilemma situations such as these, the students reported a willingness to act. The students also report considerably greater likelihood of whistleblowing internally than externally.     

A statistic to check model adequacy in time series

A simple statistic is suggested to examine if the assumptions on variances in a fitted time series model is valid or not. The properties of the statistic are discussed and examples are considered.     

Forecasting contemporal time series aggregates

Forecast of a contemporal aggregate of several time series can be obtained from ‘1’ an aggregate series, ‘2’ individual component processes, or ‘3’ a joint multiple forecasting model. Through general Hilbert space theory and some illustrative examples, this paper establishes the relative efficiencies among the three methods     

Use of Biological Markers in Risk Assessment1

Measurements of intermediate end points in the carcinogenic process may reduce uncertainty in human risk assessment from bioassay data, by identifying sources of interspecies variation and dose nonlinearity. This paper describes desirable properties of such markers: persistence, predictive power, temporal relevance, and consistency across dose rate and species. We illustrate these properties by evaluating markers for squamous cell nasal carcinoma in rodents exposed to formaldehyde. We also discuss design issues for bioassays that evaluate markers and tumors simultaneously at necropsy.     

Exact Goodness‐of‐Fit Testing for the Ising Model

The Ising model is one of the simplest and most famous models of interacting systems. It was originally proposed to model ferromagnetic interactions in statistical physics and is now widely used to model spatial processes in many areas such as ecology, sociology, and genetics, usually without testing its goodness of fit. Here, we propose various test statistics and an exact goodness‐of‐fit test for the finite‐lattice Ising model. The theory of Markov bases has been developed in algebraic statistics for exact goodness‐of‐fit testing using a Monte Carlo approach. However, finding a Markov basis is often computationally intractable. Thus, we develop a Monte Carlo method for exact goodness‐of‐fit testing for the Ising model that avoids computing a Markov basis and also leads to a better connectivity of the Markov chain and hence to a faster convergence. We show how this method can be applied to analyze the spatial organization of receptors on the cell membrane.