Sequence Comparison Via Alignment and Gibbs Sampling: A Formal Analysis of the Emergence of the Modern Sociological Article

Various substantive literatures in sociology seek small regularities in sequences: turning points in the life course, catalytic moments in organizational change, sharp turns in occupational trajectories, and the like. Commonly these are turning points, but they may also be simple local patterns. This paper reports a method for discovering such regularities even when they are quite faint, applying that method to rhetorical regularities in sociological articles. The paper begins by analyzing the overall sequence structure of such articles and then gives a basic introduction to Gibbs sampling, one member of the broader class of Markov chain Monte Carlo (MCMC) methods. It then reports an algorithm employing Gibbs sampling to find local sequence regularities and applies that algorithm to demonstrate the subsequence regularities present in sociological articles. Substantively, the paper shows that the rhetorical structure of sociological articles changed from one pattern to another in the period 1895–1965 and that certain faint but standard rhetorical subsequences became characteristic of articles in the later period. Methodologically, it introduces a broad class of methods that provide effective approaches to a number of previously intractable statistical questions.     

A simple monotone process with application to radiocarbon-dated depth chronologies

Summary.  We propose a new and simple continuous Markov monotone stochastic process and use it to make inference on a partially observed monotone stochastic process. The process is piecewise linear, based on additive independent gamma increments arriving in a Poisson fashion. An independent increments variation allows very simple conditional simulation of sample paths given known values of the process. We take advantage of a reparameterization involving the Tweedie distribution to provide efficient computation. The motivating problem is the establishment of a chronology for samples taken from lake sediment cores, i.e. the attribution of a set of dates to samples of the core given their depths, knowing that the age–depth relationship is monotone. The chronological information arises from radiocarbon (¹⁴C) dating at a subset of depths. We use the process to model the stochastically varying rate of sedimentation.     

The spatial structure of epidemic emergence: geographical aspects of poliomyelitis in north-eastern USA, July-October 1916

Summary.  The great epidemic of poliomyelitis which swept New York City and surrounding territory in the summer of 1916 eclipsed all previous global experience of the disease. We draw on epidemiological information that is included in the seminal US Public Health Bulletin 91, 'Epidemiologic studies of poliomyelitis in New York City and the northeastern United States during the year 1916' (Washington DC, 1918), to re-examine the spatial structure of the epidemic. For the main phase of transmission of the epidemic, July–October 1916, it is shown that the maximum concentration of activity of poliomyelitis occurred within a 128-km radius of New York City. Although the integrity of the poliomyelitis cluster was maintained up to approximately 500 km from the metropolitan focus, the level and rate of propagation of disease declined with distance from the origin of the epidemic. Finally, it is shown that the geographical transmission of the epidemic in north-eastern USA probably followed a process of mixed contagious–hierarchical diffusion.     

ESTIMATION OF THE CONCENTRATION PARAMETERS OF THE FISHER MATRIX DISTRIBUTION ON 50(3) AND THE BINGHAM DISTRIBUTION ON Sq, q≥ 2

Two procedures are considered for estimating the concentration parameters of the Fisher matrix distribution for rotations or orientations in three dimensions. The first is maximum likelihood. The use of a convenient 1-dimensional integral representation of the normalising constant, which greatly simplifies the computation, is suggested. The second approach exploits the equivalence of the Fisher distribution for rotations in three dimensions, and the Bingham distribution for axes in four dimensions. We describe a pseudo likelihood procedure which works for the Bingham distribution in any dimension. This alternative approach does not require numerical integration. Results on the asymptotic efficiency of the pseudo likelihood estimator relative to the maximum likelihood estimator are given, and the two estimators are compared in the analysis of a well-known vectorcardiography dataset.     

How human resource outsourcing affects organizational learning in the knowledge economy

Adaptability and knowledge management, key elements of organizational learn-ing, are critical to organizational success as a result of a fundamental shift towards a knowledge economy. HR outsourcing and the growth in contingent work can result in a significant loss in learning capital through a breakdown in the psychological contract. We explore how to preserve HR's strategic role in facilitating organizational learning in the new outsourcing and offshoring con-text. The problem is compounded if outsourcing is introduced for cost control rather than strategic refocusing reasons. We suggest that managers can posi-tively influence the relationship between outsourcing and organizational learn-ing through internal marketing tactics and enriched psychological contracts. A previous version of this paper was presented at the Administrative Sciences Association of Canada (ASAC) Annual Meeting, Toronto, Canada, June 2005.     

Overcoming Market Constraints on Pro‐Poor Agricultural Growth in Sub‐Saharan Africa

In sub‐Saharan Africa, there is fairly broad agreement that increased investment in key public goods such as roads and communications infrastructure, agricultural research and water control will be required if revitalised agricultural development is to take place. However, it has proved more difficult to reach agreement on what needs to be done to improve the performance of agricultural markets. In this article we set out an agenda for investment and policy reform in this area, providing a brief theoretical examination of the co‐ordination problems involved before examining in turn demand and supply constraints affecting smallholder farmers, and policies for price stabilisation and the co‐ordination of support services. We also argue that increased attention needs to be paid to governance issues.     

Daily Variation in Adolescents' Sleep,Activities, and Psychological Well‐Being

The daily diary method was used to examine the daily dynamics of adolescent sleep time, activities, and psychological well‐being among an ethnically diverse sample of over 750 adolescents approximately 14–15 years of age. Studying and stressful demands during the day were modestly but consistently associated with less sleep that evening. Receiving less sleep at night, in turn, was modestly but consistently related to higher levels of anxiety, depressive feelings, and fatigue during the following day. In addition, the daily variability in adolescents' sleep time was notable and just as important for the youths' average levels of daily psychological well‐being as was the average amount of time spent sleeping each night. A small number of ethnic and gender differences emerged in the dynamics of adolescent sleep, activities, and well‐being. Discussion focuses on the importance of examining variability in adolescents' sleep behaviors in order to better understand the implications of sleep for adolescent well‐being and development.     

Random effects and shrinkage estimation in capture-recapture models

We discuss the analysis of random effects in capture-recapture models, and outline Bayesian and frequentists approaches to their analysis. Under a normal model, random effects estimators derived from Bayesian or frequentist considerations have a common form as shrinkage estimators. We discuss some of the difficulties of analysing random effects using traditional methods, and argue that a Bayesian formulation provides a rigorous framework for dealing with these difficulties. In capture-recapture models, random effects may provide a parsimonious compromise between constant and completely time-dependent models for the parameters (e.g. survival probability). We consider application of random effects to band-recovery models, although the principles apply to more general situations, such as Cormack-Jolly-Seber models. We illustrate these ideas using a commonly analysed band recovery data set.