Medicine and Health Sciences Commons^™

Preschool Parent-Pediatrician Consultations And Predictive Referral Patterns For Problematic Behaviors, John Fanton, Brittany Macdonald, Elizabeth Harvey

Elizabeth (Lisa) Harvey

Objective—The present study examined parents’ reports of the frequency, nature, and outcome of pediatrician consultation and interventions about significant preschool behavior problems. Method—Parents were asked whether they consulted or not with their pediatric providers about disruptive behavioral problems during a longitudinal study of preschool children. Results—Eighty 4-year-old children had parents who had consulted with their pediatricians versus 90 children whose parents did not. Children who eventually met criteria for Attention Deficit/ Hyperactivity Disorder (ADHD) or Oppositional Defiant Disorder (ODD) two years later, received different pediatric interventions at age 4 than children who did not have a diagnosis, χ2 (2) = …

Application Of Two Machine Learning Algorithms To Genetic Association Studies In The Presence Of Covariates, Bareng As Nonyane, Andrea S. Foulkes

Andrea S Foulkes

Background - Population-based investigations aimed at uncovering genotype-trait associations often involve high-dimensional genetic polymorphism data as well as information on multiple environmental and clinical parameters. Machine learning (ML) algorithms offer a straightforward analytic approach for selecting subsets of these inputs that are most predictive of a pre-defined trait. The performance of these algorithms, however, in the presence of covariates is not well characterized. Methods and Results - In this manuscript, we investigate two approaches: Random Forests (RFs) and Multivariate Adaptive Regression Splines (MARS). Through multiple simulation studies, the performance under several underlying models is evaluated. An application to a cohort …

Lexical And Indexical Cues In Masking By Competing Speech, Karen S. Helfer, Richard L. Freyman

Karen S Helfer

Three experiments were conducted using the TVM sentences, a new set of stimuli for competing speech research. These open-set sentences incorporate a cue name that allows the experimenter to direct the listener's attention to a target sentence. The first experiment compared the relative efficacy of directing the listener's attention to the cue name versus instructing the subject to listen for a particular talker's voice. Results demonstrated that listeners could use either cue about equally well to find the target sentence. Experiment 2 was designed to determine whether differences in intelligibility among talkers' voices that were noted when three utterances were …

Estrogen And Progesterone Induce Persistent Increases In P53-Dependent Apoptosis And Suppress Mammary Tumors In Balb/C-Trp53+/- Mice, Karen Dunphy, Anneke C. Blackburn, Haoheng Yan, Lauren R. O'Connell, D Joseph Jerry

Karen Dunphy

Introduction Treatment with estrogen and progesterone (E+P) mimics the protective effect of parity on mammary tumors in rodents and depends upon the activity of p53. The following experiments tested whether exogenous E+P primes p53 to be more responsive to DNA damage and whether these pathways confer resistance to mammary tumors in a mouse model of Li-Fraumeni syndrome. Methods Mice that differ in p53 status (Trp53+/+, Trp53+/-, Trp53-/-) were treated with E+P for 14 days and then were tested for p53-dependent responses to ionizing radiation. Responses were also examined in parous and age-matched virgins. The effects of hormonal exposures on tumor …

Association Between Dietary Glycemic Index, Glycemic Load, And High-Sensitivity C-Reactive Protein, Jennifer A. Griffith, Yusheng Ma, Lisa Chasan-Taber, Barbara C. Olendzki, David E. Chiriboga, Edward J. Stanek, Philip A. Merriam, Ira S. Ockene

Edward J. Stanek

OBJECTIVE:

This study examined the relation between quality of dietary carbohydrate intake, as measured by glycemic index (GI) and glycemic load (GL), and serum high-sensitivity C-reactive protein (hs-CRP) levels. METHODS:

During a 1-y observational study, data were collected at baseline and at each quarter thereafter. GI and GL were calculated from multiple 24-h dietary recalls (24HRs), 3 randomly selected 24HRs at every quarter, with up to 15 24HRs per participant. The hs-CRP was measured in blood samples collected at baseline and each of the four quarterly measurement points. Multivariable linear mixed models were used to examine the cross-sectional and longitudinal …

Effect Of Diet And Exercise On Body Composition, Energy Intake And Leptin Levels In Overweight Women And Men, Stella L. Volpe, Hati Kobusingye, Smita Bailfur, Edward J. Stanek

Edward J. Stanek

OBJECTIVE: To investigate the effect of diet alone (D), exercise alone (E), and a combination of diet and exercise (DE) on body weight, body composition, energy intake, blood pressure, serum lipid and leptin levels, and fitness levels in mildly obese sedentary women and men. DESIGN: The three interventions were compared in a randomized longitudinal study design. The exercise programs were supervised for six months, after which participants in E and DE were provided with exercise equipment to take home. SUBJECTS: 90 adult overweight women and men (age: 44.2 +/- 7.2 years; BMI = 30.5 +/- 2.7 kg/m(2)). MEASUREMENTS: Body weight, …

Should Adjustment For Covariates Be Used In Prevalence Estimations?, Wenjun Li, Edward J. Stanek, Elizabeth R. Bertone-Johnson

Edward J. Stanek

Background

Adjustment for covariates (also called auxiliary variables in survey sampling literature) is commonly applied in health surveys to reduce the variances of the prevalence estimators. In theory, adjusted prevalence estimators are more accurate when variance components are known. In practice, variance components needed to achieve the adjustment are unknown and their sample estimators are used instead. The uncertainty introduced by estimating variance components may overshadow the reduction in the variance of the prevalence estimators due to adjustment. We present empirical guidelines indicating when adjusted prevalence estimators should be considered, using gender adjusted and unadjusted smoking prevalence as an illustration. …

Changes In Muscle And Joint Coordination In Learning To Direct Forces, Christopher Hasson, Graham Caldwell, Richard Van Emmerik

Richard E.A. van Emmerik

While it has been suggested that biarticular muscles have a specialized role in directing external reaction forces, it is unclear how humans learn to coordinate mono- and bi-articular muscles to perform force-directing tasks. Subjects were asked to direct pedal forces in a specified target direction during one-legged cycling. We expected that with practice, performance improvement would be associated with specific changes in joint torque patterns and mono- and bi-articular muscular coordination. Nine male subjects practiced pedaling an ergometer with only their left leg, and were instructed to always direct their applied pedal force perpendicular to the crank arm (target direction) …

Aging And Speech-On-Speech Masking, Karen S. Helfer, Richard L. Freyman

Karen S Helfer

Objectives A common complaint of many older adults is difficulty communicating in situations where they must focus on one talker in the presence of other people speaking. In listening environments containing multiple talkers, age-related changes may be caused by increased sensitivity to energetic masking, increased susceptibility to informational masking (e.g., confusion between the target voice and masking voices), and/or cognitive deficits. The purpose of the present study was to tease out these contributions to the difficulties that older adults experience in speech-on-speech masking situations. Design Groups of younger, normal-hearing individuals and older adults with varying degrees of hearing sensitivity (n …

Spatial Release From Masking With Noise-Vocoded Speech, Richard L. Freyman, Uma Balakrishnan, Karen S. Helfer

Karen S Helfer

This study investigated how confusability between target and masking utterances affects the masking release achieved through spatial separation. Important distinguishing characteristics between competing voices were removed by processing speech with six-channel envelope vocoding, which simulates some aspects of listening with a cochlear implant. In the first experiment, vocoded target nonsense sentences were presented against two-talker vocoded maskers in conditions that provide different spatial impressions but not reliable cues that lead to traditional release from masking. Surprisingly, no benefit of spatial separation was found. The absence of spatial release was hypothesized to be the result of the highly positive target-to-masker ratios …

Neural Mechanisms Underlying Learning Following Semantic Mediation Treatment In A Case Of Phonologic Alexia, Jacquie Kurland, Carlos R. Cortes, Marko Wilke, Anne J. Sperling, Susan N. Lott, Malle A. Tagamets, John Vanmeter, Rhonda B. Friedman

Jacquie Kurland

Patients with phonologic alexia can be trained to read semantically impoverished words (e.g., functors) by pairing them with phonologically-related semantically rich words (e.g, nouns). What mechanisms underlie success in this cognitive re-training approach? Does the mechanism change if the skill is “overlearned”, i.e., practiced beyond criterion? We utilized fMRI pre- and post-treatment, and after overlearning, to assess treatment-related functional reorganization in a patient with phonologic alexia, two years post left temporoparietal stroke. Pre-treatment, there were no statistically significant differences in activation profiles across the sets of words. Post-treatment, accuracy on the two trained sets improved. Compared with untrained words, reading …

Monitoring Microbial Populations On Wide-Body Commercial Passenger Aircraft, Taylor L. Mckernan, K M. Wallingford, M J. Hein, H A. Burge, Christine A. Rogers, R Herrick

Christine A. Rogers

Although exposure to bacteria has been assessed in cabin air previously, minimal numbers of samples have been collected in-flight. The purpose of this research was to comprehensively characterize bacterial concentrations in the aircraft cabin. Twelve randomly selected flights were sampled on Boeing-767 aircraft, each with a flight duration between 4.5 and 6.5 h. N-6 impactors were used to collect sequential, triplicate air samples in the front and rear of coach class during six sampling intervals throughout each flight: boarding, mid-climb, early cruise, mid-cruise, late cruise and deplaning. Comparison air samples were also collected inside and outside the airport terminals at …

A Likelihood-Based Approach To Mixed Modeling With Ambiguity In Cluster Identifiers, Andrea S. Foulkes, Recai Yucel, Xiaohong Li

Andrea S Foulkes

This manuscript describes a novel, linear mixed-effects model–fitting technique for the setting in which correlated data indicators are not completely observed. Mixed modeling is a useful analytical tool for characterizing genotype–phenotype associations among multiple potentially informative genetic loci. This approach involves grouping individuals into genetic clusters, where individuals in the same cluster have similar or identical multilocus genotypes. In haplotype-based investigations of unrelated individuals, corresponding cluster assignments are unobservable since the alignment of alleles within chromosomal copies is not generally observed. We derive an expectation conditional maximization approach to estimation in the mixed modeling setting, where cluster assignments are ambiguous. …