Learning Bayesian network structure from massive datasets: The ”sparse candidate” algorithm

Learning Bayesian networks is often cast as an optimization problem, where the computational task is to find a structure that maximizes a statistically motivated score. By and large, existing learning tools address this optimization problem using standard heuristic search techniques. Since the search space is extremely large, such search procedures can spend most of the time examining candidates that are extremely unreasonable. This problem becomes critical when we deal with data sets that are large both in the number of instances, and the number of attributes. In this paper, we introduce an algorithm that achieves faster learning by restricting the search space. This iterative algorithm restricts the parents of each variable to belong to a small subset of candidates. We then search for a network that satisfies these constraints. The learned network is then used for selecting better candidates for the next iteration. We evaluate this algorithm both on synthetic and real-life data. Our results show that it is significantly faster than alternative search procedures without loss of quality in the learned structures.

HUD feedback to minimize the risk of cellular phone use and number entry while driving

There has been considerable public debate as to whether people should be allowed to use cell phones while driving. In several countries, this debate has led to restrictions on cell phone use while driving. Japanese data suggests that answering a call might be the most dangerous task, followed by dialing. Several questions were therefore selected for further investigation. 1. How does the dialing device and its location affect task time, errors, driving performance, and ratings of workload? 2. How does the location of the display (especially head-up displays) affect those same measures? 3. For various control-display combinations, how are those measures affected by driving workload? The experiment will be comprised of two distinct portions. In the first portion, subjects will drive a simulator on straight roads (implying controlled workload) while dialing a 10-digit telephone number using 6 device configurations with various displays. During the second test portion, participants will drive a simulator on roads with curves of different radii while entering phone numbers for 3 different device combinations. The following device/location configurations will be examined: (1) 10-key keypad on the steering wheel spoke, (2) 10-key keypad on the center console, (3) joystick on the steering wheel spoke, (4) joystick mounted on the center console, (5) hand held 10- key keypad, (6) a cross key on the touch screen, and (7) a 10 key keypad on the touch screen. These devices will be used for 3 display conditions: (1) head up display, (2) monitor mounted in the center console, or (3) no display.Nissan Research Centerhttp://deepblue.lib.umich.edu/bitstream/2027.42/92345/1/102881.pd

Relativistic Diskoseismology. I. Analytical Results for 'Gravity Modes'

We generalize previous calculations to a fully relativistic treatment of adiabatic oscillations which are trapped in the inner regions of accretion disks by non-Newtonian gravitational effects of a black hole. We employ the Kerr geometry within the scalar potential formalism of Ipser and Lindblom, neglecting the gravitational field of the disk. This approach treats perturbations of arbitrary stationary, axisymmetric, perfect fluid models. It is applied here to thin accretion disks. Approximate analytic eigenfunctions and eigenfrequencies are obtained for the most robust and observable class of modes, which corresponds roughly to the gravity (internal) oscillations of stars. The dependence of the oscillation frequencies on the mass and angular momentum of the black hole is exhibited. These trapped modes do not exist in Newtonian gravity, and thus provide a signature and probe of the strong-field structure of black holes. Our predictions are relevant to observations which could detect modulation of the X-ray luminosity from stellar mass black holes in our galaxy and the UV and optical luminosity from supermassive black holes in active galactic nuclei.Comment: 31 pages, 6 figures, uses style file aaspp4.sty, prepared with the AAS LATEX macros v4.0, significant revision of earlier submission to include modes with axial index m>

Partnering with Parteras: Multi-Collaborator International Service-Learning Project Impacts on Traditional Birth Attendants in Mexico

Medical students are increasingly seeking global health service-learning opportunities; however, the impact of these interventions is often not assessed. In this article, the authors describe a model for global health service-learning programs as well as a pilot tool for assessing program impacts on populations traditionally difficult to evaluate.  Specifically, a group of medical students from the United States, in collaboration with local health officials and a global NGO, successfully implemented a training program for parteras, or traditional birth attendants, in Mexico. The training included educational objectives from the Ministry of Health.  A pilot assessment tool was developed which included oral pretest and posttest self-reported knowledge and task-specific ability in 12 program-specific categories. The assessment was administered in an effort to determine educational impact: parteras, who were receptive to students as teachers, reported increased knowledge and skill in all topics except nutrition and postpartum care. The results of the assessment suggest that undergraduate medical students, when collaborating with a facilitating organization, community-based healthcare workers, and local ministries of health, can improve lay birth attendants’ confidence in basic obstetric knowledge and skills through global service-learning. Moreover, creative assessments are required to understand impacts on difficult to access populations.

An epigenome-wide association study of child appetitive traits and DNA methylation

The etiology of childhood appetitive traits is poorly understood. Early-life epigenetic processes may be involved in the developmental programming of appetite regulation in childhood. One such process is DNA methylation (DNAm), whereby a methyl group is added to a specific part of DNA, where a cytosine base is next to a guanine base, a CpG site. We meta-analyzed epigenome-wide association studies (EWASs) of cord blood DNAm and early-childhood appetitive traits. Data were from two independent cohorts: the Generation R Study (n = 1,086, Rotterdam, the Netherlands) and the Healthy Start study (n = 236, Colorado, USA). DNAm at autosomal methylation sites in cord blood was measured using the Illumina Infinium HumanMethylation450 BeadChip. Parents reported on their child's food responsiveness, emotional undereating, satiety responsiveness and food fussiness using the Children's Eating Behaviour Questionnaire at age 4–5 years. Multiple regression models were used to examine the association of DNAm (predictor) at the individual site- and regional-level (using DMRff) with each appetitive trait (outcome), adjusting for covariates. Bonferroni-correction was applied to adjust for multiple testing. There were no associations of DNAm and any appetitive trait when examining individual CpG-sites. However, when examining multiple CpGs jointly in so-called differentially methylated regions, we identified 45 associations of DNAm with food responsiveness, 7 associations of DNAm with emotional undereating, 13 associations of DNAm with satiety responsiveness, and 9 associations of DNAm with food fussiness. This study shows that DNAm in the newborn may partially explain variation in appetitive traits expressed in early childhood and provides preliminary support for early programming of child appetitive traits through DNAm. Investigating differential DNAm associated with appetitive traits could be an important first step in identifying biological pathways underlying the development of these behaviors.</p

Lactation and neonatal nutrition: defining and refining the critical questions.

This paper resulted from a conference entitled "Lactation and Milk: Defining and refining the critical questions" held at the University of Colorado School of Medicine from January 18-20, 2012. The mission of the conference was to identify unresolved questions and set future goals for research into human milk composition, mammary development and lactation. We first outline the unanswered questions regarding the composition of human milk (Section I) and the mechanisms by which milk components affect neonatal development, growth and health and recommend models for future research. Emerging questions about how milk components affect cognitive development and behavioral phenotype of the offspring are presented in Section II. In Section III we outline the important unanswered questions about regulation of mammary gland development, the heritability of defects, the effects of maternal nutrition, disease, metabolic status, and therapeutic drugs upon the subsequent lactation. Questions surrounding breastfeeding practice are also highlighted. In Section IV we describe the specific nutritional challenges faced by three different populations, namely preterm infants, infants born to obese mothers who may or may not have gestational diabetes, and infants born to undernourished mothers. The recognition that multidisciplinary training is critical to advancing the field led us to formulate specific training recommendations in Section V. Our recommendations for research emphasis are summarized in Section VI. In sum, we present a roadmap for multidisciplinary research into all aspects of human lactation, milk and its role in infant nutrition for the next decade and beyond

Prophetic Reading: Sisterhood and Psychoanalysis in H.D.’s HERmione

This article offers a comparative reading of H.D.’s 1927 kunstlerroman à clef, HERmione, and Freud’s Dora alongside an intertextual close reading of its dense web of literary allusions in order to argue that it offers a sustained critique of Freudian psychoanalysis and an alternative origin story for the condition of hysteria. Drawing on the notion of prophecy as it is thematised in the novel, the article demonstrates H.D.’s prefiguring of Juliet Mitchell’s recent reconfiguration of hysteria as a response to, replacement by, or failure of identification with a sibling