Split Hamiltonian Monte Carlo

We show how the Hamiltonian Monte Carlo algorithm can sometimes be speeded up by “splitting” the Hamiltonian in a way that allows much of the movement around the state space to be done at low computational cost. One context where this is possible is when the log density of the distribution of interest (the potential energy function) can be written as the log of a Gaussian density, which is a quadratic function, plus a slowly-varying function. Hamiltonian dynamics for quadratic energy functions can be analytically solved. With the splitting technique, only the slowly-varying part of the energy needs to be handled numerically, and this can be done with a larger stepsize (and hence fewer steps) than would be necessary with a direct simulation of the dynamics. Another context where splitting helps is when the most important terms of the potential energy function and its gradient can be evaluated quickly, with only a slowly-varying part requiring costly computations. With splitting, the quick portion can be handled with a small stepsize, while the costly portion uses a larger stepsize. We show that both of these splitting approaches can reduce the computational cost of sampling from the posterior distribution for a logistic regression model, using either a Gaussian approximation centered on the posterior mode, or a Hamiltonian split into a term that depends on only a small number of critical cases, and another term that involves the larger number of cases whose influence on the posterior distribution is small.     

“Make Sure You’re Not Getting Yourself in Trouble:” Building Sexual Relationships and Preventing Sexual Violence at the U.S. Military Academy at West Point

Sexual violence continues to present a problem on college campuses nationwide and among members of the U.S. military. This study attended to patterns of response in how students (cadets) at the U.S. Military Academy (West Point) discussed sexual and romantic relationships, both potential and actual, in order to examine how, if at all, they enact their sexuality-related values. Constructivist grounded theory was used to analyze semistructured interviews with three male and three female cadets from each of the 4 years of the undergraduate program, in which they are intended to become “leaders of character” who will serve as Army officers. Findings indicated limitations in cadets’ access to developing and implementing sexuality-related skills within this context. Cadets’ fear and distrust erected barriers to their pursuing their desires; the ways in which cadets avoided getting in trouble for sexual harassment or sexual assault shifted responsibility from a potential perpetrator onto a potential victim; and cadets were caught in dilemmas regarding romantic relationships as sources of both emotional support and social stigma. These findings have implications for promoting gender equity and for preventing sexual violence at this institution and at others like it, including both university campuses and other military settings.     

Leadership of highly creative people in highly creative fields: A historiometric study of scientific leaders

In recent years there has been a marked increase in the study of the influence of leadership on creativity, and the effects of this relationship on organizational performance. While a number of explanations have been broached with regard to the positive effects of leadership on creativity, many of these studies propose different, and often contradictory, methods for leaders to achieve these positive effects on creativity within their organizations and work groups. Additionally, little work has been done examining the effects of leadership on highly creative people in fields requiring creativity. The purpose of this study is to examine two existing leadership theories with regard to their viability as models to explain creative performance of eminent scientists. Eminent scientists represent a population of leaders of highly creative individuals in a field that values the production of innovative ideas and products as a marker of performance. Ninety-three excerpts from the biographies of scientists were content coded for leader behaviors and performance criteria. The results of this analysis indicate that a model based on strategic planning and product championing may serve to explain the positive effects of leadership on creativity in a highly creative population.     

The Read Feed: Reviews

Abstract

Michelle DeMars reviews Academic Libraries for Commuter Students: Research-Based Strategies. Hayley Moreno reviews Coding with XML for Efficiencies in Cataloging and Metadata: Practical Applications of XSD, XSLT, and XQuery.     

In search of rigor, relevance, and legitimacy: what drives the impact of publications?

In this study, we introduce the concept of legitimacy to the rigor-relevance debate and investigate empirically how rigor, relevance, and legitimacy are related to the process of knowledge dissemination within a research field. We argue that this analysis has been a missing piece in the debate on rigor and relevance when institutional logics about what constitutes both elements lead researchers to act according to what they perceive to be appropriate behavior in the research field. We draw on insights from the micro and macro levels of institutional theory to show how researchers aiming to bestow legitimacy on their own work conform to these “rules of the game”. Using meta-analytical techniques, we focus on the field of strategic entrepreneurship and analyze how rigor- and relevance-related characteristics of studies in this field are linked to their legitimacy and therefore to the impact they have in the research community.     

Sociology and the European Court of Human Rights

This article offers a sociological analysis of the jurisprudence of the European Court of Human Rights (ECtHR). Adopting a sociological jurisprudence approach, the article aims to demonstrate the unique and valuable contribution that sociology can make to understanding key aspects of international human rights law. Whilst the article seeks to develop an agenda for critical sociological research on human rights law, it also aims to persuade those charged with the supervision of human rights of the value of sociological analysis. To achieve this, the article focuses on three separate but inter‐related aspects of ECtHR jurisprudence: first, it considers the ECtHR's approach to consensus in its adjudication of human rights complaints; second, it examines the social control implications of the ECtHR's decisions and judgments; and third, it assesses how conceptualizations of social identity are often foundational to the ECtHR's reasoning.     

Measuring Sharedness of Team-Related Knowledge: Design and Validation of a Shared Mental Model Instrument

Many researchers have explored how people share and construct similar mental models in teams. They have claimed that successful team performance depends on a shared mental model of team members about task, team, equipment and situation. Most of the literature has illustrated simplified relationships between a team's mental model and their performance without a valid instrument addressing the confined and relevant constructs of a shared mental model. This paper describes the instrument development steps and the conceptual framework for factors associated with shared mental models. After development and refinement, the instrument was finalized for use to measure team-related knowledge. The final instrument consists of 42 items that are linked to the five emergent factors of shared mental models including general task and team knowledge, general task and communication skills, attitude toward teammates and task, team dynamics and interactions, and team resources and working environment.     

The Detection of Influential Observations for Allocation,Separation, and the Determination of Probabilities in a Bayesian Framework

Normal theory separation and allocation problems are discussed from a predictive point of view. Influence statistics are defined and employed to ascertain the impact that particular observations will have on the inferential goals—allocation of future observations, separation between populations, and the determination of probabilities for future cases. Methods are illustrated on a collection of financial data taken from Johnson and Wichern (1982).     

Staying strong: gender ideologies among African-American adolescents and the implications for HIV/STI prevention

This paper explores adolescents' definitions of what it means to be a man and a woman, the psycho-social context surrounding the formation of gender ideologies and their relationship to HIV/STI prevention. Semi-structured, in-depth interviews were conducted with fifty African-American adolescents living in Baltimore, Maryland. Female gender ideologies included economic independence, emotional strength and caretaking. Male gender ideologies emphasized financial responsibility, toughness and sexual prowess. Findings suggest that stronger adherence to male gender ideologies related to toughness and sexual prowess is influenced by male participants' perceived inability to fulfill their primary gender role as economic providers and the importance of gaining approval from male peers in the absence of adult male role models. Stronger adherence to female gender ideologies related to emotional strength and caretaking may be linked to a heightened desire for male intimacy and tolerance of male sexual risk behavior. Implications of the gender ideologies documented and their commonalities are discussed in terms of HIV/STI prevention.