Learning discrete decomposable graphical models via constraint optimization

Statistical model learning problems are traditionally solved using either heuristic greedy optimization or stochastic simulation, such as Markov chain Monte Carlo or simulated annealing. Recently, there has been an increasing interest in the use of combinatorial search methods, including those based on computational logic. Some of these methods are particularly attractive since they can also be successful in proving the global optimality of solutions, in contrast to stochastic algorithms that only guarantee optimality at the limit. Here we improve and generalize a recently introduced constraint-based method for learning undirected graphical models. The new method combines perfect elimination orderings with various strategies for solution pruning and offers a dramatic improvement both in terms of time and memory complexity. We also show that the method is capable of efficiently handling a more general class of models, called stratified/labeled graphical models, which have an astronomically larger model space.     

Emotional Transactions in the Paris Subway: Combining Naturalistic Videotaping,Objective Facial Coding and Sequential Analysis in the Study of Nonverbal Emotional Behavior

We report on what, to our knowledge, represents the first study of nonverbal emotional behavior in crowded public places combining naturalistic videotaping of situated activity, objective coding of facial movement, and sequential analysis of behavior. In the first part of the study we argue that passengers do not lose emotional sensitivity to physical contact as density (passengers per square meter) increases, which indicates that physical contact is experienced as a territorial intrusion regardless of crowdedness. In the second part of the study, we suggest that passengers resolve the emotions due to intrusive physical contacts through two interactional strategies involving facial movements usually interpreted as “expressions of emotions.” Since proxemic violations seem to represent a pervasive emotion elicitor, the protocol can be extended to other means of transportation and replicated in other locations. We conclude that the methodology provides an effective tool for theory-building in the study of nonverbal emotional behavior.     

Unruly Voices in the Museum

ABSTRACT

This article addresses the use of audio recordings and oral memory for the critical engagement with colonial pasts in ethnographic museums by focusing on the traveling exhibition What We See, curated by Anette Hoffmann (2009). Specifically, it draws on Jeffrey Feldman's notion of colonial “contact points,” i.e. material traces of colonial encounter, to highlight the exhibition's ability to convey and critique the sensory experience of colonial contact. In What We See, this colonial contact consisted in an anthropometric project conducted in South-West Africa, today's Namibia, in 1931, resulting in an archive of anthropometric measurements and photographs, life-casts, and phonographic recordings. The exhibition proposed an innovative way of reworking this archive by staging an intricate interplay between sound and sight, thereby disrupting conventional ocularcentric forms of display. However, this multisensory approach provoked highly divergent reactions at its various exhibition venues. This article argues that the divergent reactions in Cape Town, South Africa, and Vienna, Austria, were due to different levels of what Ann Stoler describes as “colonial aphasia”—that is the context-dependent difficulty of addressing disquieting colonial pasts and its sensory dimensions.     

Impacts of urban sprawl on species richness of plants,butterflies, gastropods and birds: not only built-up area matters

Urban growth is a major factor of global environmental change and has important impacts on biodiversity, such as changes in species composition and biotic homogenization. Most previous studies have focused on effects of urban area as a general measure of urbanization, and on few or single taxa. Here, we analyzed the impacts of the different components of urban sprawl (i.e., scattered and widespread urban growth) on species richness of a variety of taxonomic groups covering mosses, vascular plants, gastropods, butterflies, and birds at the habitat and landscape scales. Besides urban area, we considered the average age, imperviousness, and dispersion degree of urban area, along with human population density, to disentangle the effects of the different components of urban sprawl on biodiversity. The study was carried out in the Swiss Plateau that has undergone substantial urban sprawl in recent decades.Vascular plants and birds showed the strongest responses to urban sprawl, especially at the landscape scale, with non-native and ruderal plants proliferating and common generalist birds increasing at the expense of specialist birds as urban sprawl grew. Overall, urban area had the greatest contribution on such impacts, but additional effects of urban dispersion (i.e., increase of non-native plants) and human population density (i.e., increases of ruderal plants and common generalist birds) were found. Our findings support the hypothesis that negative impacts of urban sprawl on biodiversity can be reduced by compacting urban growth while still avoiding the formation of very densely populated areas.     

Young adults’ hopes for the long-term future: from re-enchantment with technology to faith in humanity

Recent scholarly research has claimed that young people are predominantly concerned with their immediate ‘horizon of planning’, resulting in an outlook upon the future that is dominated by present-day concerns. By distinguishing between choices and plans, on the one hand, and hope and faith, on the other, this article analyses how young people relate to the future through their attitudes about responsibility and technology in order to complicate this narrative. The data are drawn from an interview project in which 28 young adults (aged 18–34) discuss both their own future and a general idea of the future of society. Two key findings are discussed. Firstly, respondents are found to place faith in the potential of technology to mitigate future predicaments, and secondly, respondents are found to ascribe mystical or magical qualities to technology. Drawing on these findings, this article suggests that the oft-cited attitude that technology will develop in time to meet the needs of the future does not simply signify a deferral of responsibility onto future generations. Instead, by drawing on scholarship on re-enchantment it is argued that for young adults technological development can represent a refuge of faith and hope for the future.     

Exploring the nonverbal facet of ethnic discrimination: a field experiment on anti-Roma racism in the Paris métro

A field experiment on the discrimination of Roma migrants from Eastern Europe was conducted in two stations of the Paris metro to explore the behaviors that may communicate misrecognition in everyday encounters. An actress asked for help to randomly chosen passengers on a metro platform, wearing a glaringly Romani skirt in the treatment condition but an unconspicuous middle-class style in the control condition. In interaction with the actress wearing the Romani skirt, passengers were found to enact the so-called “visual dominance pattern”, and male passengers in particular were found to keep greater distances. Reverse discrimination also occurred as women kept shorter distances from the actress bearing the ethnic stigma. Last, passengers helped less the stigmatized actress, but only in one of the two metro stations where trials were conducted.     

HRD in 2020: a hop-on,hop-off city tour

This article reports on the outcome of a Future Search Conference in the UK to consider human resource development (HRD) in 2020 and beyond. We firstly consider themes from the past into the present. This includes the persistence of solutions in HRD that are systematic, predictable, how apprenticeships in the UK have had to accommodate government policies to ameliorate youth unemployment and the long-standing difficulty for HRD of failing to demonstrate a return on investment (ROI) on activities. We then present four scenarios based on key questions for the future relating to value of HRD and whether this will be a future for HRD. Reponses to the questions form scenario logics which we present against the theme of city tour. Each scenario is explained against the presented logic with positive, negative, ambiguous and uncertain implications for HRD. We suggest that each scenario carries a glimpse of what might be.     

Academic economists behaving badly? A survey on three areas of unethical behavior

This article measures the degree to which academic economists have engaged in unethical behavior and the degree to which academic economists believe the profession as a whole engages in unethical behavior. Three main types of unethical behavior are examined: (1) falsification of research; (2) expropriation of graduate student research or including an undeserving co-author on a research paper; and (3) exchange of grades for gifts, money, or sex. Using a unique data set gathered at the 1998 American Economic Association (AEA) meetings, we find that there is a significant amount of misconduct, particularly in the second category.     

A Note on the Large Sample Properties of Estimators Based on Generalized Linear Models for Correlated Pseudo‐observations

Pseudo‐values have proven very useful in censored data analysis in complex settings such as multi‐state models. It was originally suggested by Andersen et al., Biometrika, 90, 2003, 335 who also suggested to estimate standard errors using classical generalized estimating equation results. These results were studied more formally in Graw et al., Lifetime Data Anal., 15, 2009, 241 that derived some key results based on a second‐order von Mises expansion. However, results concerning large sample properties of estimates based on regression models for pseudo‐values still seem unclear. In this paper, we study these large sample properties in the simple setting of survival probabilities and show that the estimating function can be written as a U‐statistic of second order giving rise to an additional term that does not vanish asymptotically. We further show that previously advocated standard error estimates will typically be too large, although in many practical applications the difference will be of minor importance. We show how to estimate correctly the variability of the estimator. This is further studied in some simulation studies.