10,383 research outputs found

    Associations between child and sibling levels of vigorous physical activity in low-income minority families

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    AbstractBackground and objectivesA child's level of habitual physical activity is partly determined by a familial component, but the literature is limited regarding sibling influences. Multiple studies suggest that targeting siblings is an effective strategy for improving child health behaviors.Patients and methodsWe analyze Moving to Opportunity for Fair Housing (MTO) data to study associations between the odds of a child attaining 20 min or more of vigorous physical activity at least 3 days every week and parallel measures from an older sibling and a parent. We include covariates representing the social environment such as household income and neighborhood safety.ResultsThere were 1347 study units that consisted of a child (age 11.2 y ± 2.6), an older sibling (age 14.8 y ± 2.8), and a parent (age 38.3 y ± 7.5). A child's odds of vigorous physical activity for 20 min or more was increased if the older sibling (OR 1.67; 95% CI 1.32–2.11) or parent (OR 1.36; 95% CI 1.08–1.72) had a comparable activity level compared to children whose older siblings or parents did not exhibit a comparable level of activity.ConclusionsA younger sibling's level of physical activity is positively associated with an older sibling's and/or parent's level of physical activity. Family-based approaches, especially those incorporating siblings, may be effective at increasing physical activity in children

    Tunable Low Density Palladium Nanowire Foams

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    Nanostructured palladium foams offer exciting potential for applications in diverse fields such as catalyst, fuel cell, and particularly hydrogen storage technologies. We have fabricated palladium nanowire foams using a cross-linking and freeze-drying technique. These foams have a tunable density down to 0.1% of the bulk, and a surface area to volume ratio of up to 1,540,000:1. They exhibit highly attractive characteristics for hydrogen storage, in terms of loading capacity, rate of absorption and heat of absorption. The hydrogen absorption/desorption process is hysteretic in nature, accompanied by substantial lattice expansion/contraction as the foam converts between Pd and PdHx.Comment: 17 pages, 4 figure

    Mapping the rules: conceptual and logical relationships in a system for pediatric clinical decision support

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    The Child Health Improvement through Computer Automation (CHICA) system uses evidence-based guidelines and information collected in the clinic and stored in an electronic medical record (EMR) to inform physician and patient decision making. CHICA helps physicians to identify and select relevant screenings and also provides personalized, just-in-time information for patients. This system relies on a database of Medical Logic Modules (MLMS) written in the Arden Rules syntax. These MLMs store observations (StorObs) during the clinical encounter which trigger potential screenings and preventive health interventions for discussion with the patient or for follow up at the next visit. This poster shows how informationists worked with the CHICA team to describe the MLMs using standard vocabularies, including Medical Subject Headings (MeSH) and Logical Observation Identifiers Names and Codes (LOINC). After assigning keywords to the database of MLMs, the informationists used visualization tools to generate maps. These maps show how rules are related by logic (shared StorObs) and by concept (shared vocabulary). The CHICA team will use these maps to identify gaps in the clinical decision support database and (if needed) to develop rules which bridge related but currently isolated concepts.NIH 1R01LM010923-0

    Scaling metagenome sequence assembly with probabilistic de Bruijn graphs

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    Deep sequencing has enabled the investigation of a wide range of environmental microbial ecosystems, but the high memory requirements for {\em de novo} assembly of short-read shotgun sequencing data from these complex populations are an increasingly large practical barrier. Here we introduce a memory-efficient graph representation with which we can analyze the k-mer connectivity of metagenomic samples. The graph representation is based on a probabilistic data structure, a Bloom filter, that allows us to efficiently store assembly graphs in as little as 4 bits per k-mer, albeit inexactly. We show that this data structure accurately represents DNA assembly graphs in low memory. We apply this data structure to the problem of partitioning assembly graphs into components as a prelude to assembly, and show that this reduces the overall memory requirements for {\em de novo} assembly of metagenomes. On one soil metagenome assembly, this approach achieves a nearly 40-fold decrease in the maximum memory requirements for assembly. This probabilistic graph representation is a significant theoretical advance in storing assembly graphs and also yields immediate leverage on metagenomic assembly

    Kinematics and helicity evolution of a loop-like eruptive prominence

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    We aim at investigating the morphology, kinematic and helicity evolution of a loop-like prominence during its eruption. We use multi-instrument observations from AIA/SDO, EUVI/STEREO and LASCO/SoHO. The kinematic, morphological, geometrical, and helicity evolution of a loop-like eruptive prominence are studied in the context of the magnetic flux rope model of solar prominences. The prominence eruption evolved as a height expanding twisted loop with both legs anchored in the chromosphere of a plage area. The eruption process consists of a prominence activation, acceleration, and a phase of constant velocity. The prominence body was composed of left-hand (counter-clockwise) twisted threads around the main prominence axis. The twist during the eruption was estimated at 6pi (3 turns). The prominence reached a maximum height of 526 Mm before contracting to its primary location and partially reformed in the same place two days after the eruption. This ejection, however, triggered a CME seen in LASCO C2. The prominence was located in the northern periphery of the CME magnetic field configuration and, therefore, the background magnetic field was asymmetric with respect to the filament position. The physical conditions of the falling plasma blobs were analysed with respect to the prominence kinematics. The same sign of the prominence body twist and writhe, as well as the amount of twisting above the critical value of 2pi after the activation phase indicate that possibly conditions for kink instability were present. No signature of magnetic reconnection was observed anywhere in the prominence body and its surroundings. The filament/prominence descent following the eruption and its partial reformation at the same place two days later suggest a confined type of eruption. The asymmetric background magnetic field possibly played an important role in the failed eruption.Comment: 9 pages, 8 figures, in press in A&

    The obesity epidemic in children: Latino children are disproportionately affected at younger ages

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    Background and objectives National surveillance clearly illustrates that U.S. children are becoming increasingly overweight. However, the timing of the onset of childhood overweight has not been well-described. Patients and methods An accelerated failure time (AFT) model was used to describe the emergence of overweight based on a 12-year collection of height and weight data of over 40,000 children. Race, sex, insurance status and their interactions were specifically examined as predictors of earlier onset of overweight. The outcome of interest was an estimate of the age at which the model predicted that a subgroup would attain a 20% prevalence of overweight. Results The three-way interaction of race, sex, and insurance status was a significant predictor of onset of overweight. The model estimated that the publicly insured Latino male subgroup had the earliest onset of overweight, attaining a prevalence of 20% overweight by 4.3 years of age. The emergence of overweight in Latino subjects was significantly earlier than that for black or white subjects, irrespective of sex or insurance status. Conclusion Regardless of sex or insurance status, overweight emerges at significantly younger ages in Latino children when compared to black and white children. Substantial numbers of Latino male children are predicted to develop overweight at preschool ages. Obesity prevention may need to be directed toward parents or children well before children enter grade-school

    Data visualization for truth maintenance in clinical decision support systems

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    Background and objectives The goal is to inform proactive initiatives to expand the knowledge base of clinical decision support systems. Design and setting We describe an initiative in which research informationists and health services researchers employ visualization tools to map logic models for clinical decision support within an electronic health record. Materials and methods We mapped relationships using software for social network analysis: NodeXL and CMAP. We defined relationships by shared observations, such as two Arden rules within medical logic modules that consider the same clinical observation, or by the presence of common keywords that were used to label rules according to standardized vocabularies. Results We studied the Child Health Improvement through Computer Automation (CHICA) system, an electronic medical record that contains 170 unique variables representing discrete clinical observations. These variables were used in 300 medical logic modules (MLM's) that prompted health care providers to deliver preventive counseling or otherwise served as clinical decision support. Using data visualization tools, we generated maps that illustrate connections, or lack thereof, between clinical topics within CHICA's MLMs. Conclusions The development of such maps may allow multiple disciplines commonly interacting over EMR platforms, and various perspectives (clinicians, programmers, informationists) to work more effectively as teams to refine the EMR by programming logic routines to address co-morbidities or other instances where domains of medical knowledge should be connected

    The Hydromagnetic Interior of a Solar Quiescent Prominence. I. Coupling between Force-balance and Steady Energy-transport

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    This series of papers investigates the dynamic interior of a quiescent prominence revealed by recent {\it Hinode} and {\it SDO/AIA} high-resolution observations. This first paper is a study of the static equilibrium of the Kippenhahn-Schl\"{u}ter diffuse plasma slab, suspended vertically in a bowed magnetic field, under the frozen-in condition and subject to a theoretical thermal balance among an optically-thin radiation, heating, and field-aligned thermal conduction. The everywhere-analytical solutions to this nonlinear problem are an extremely restricted subset of the physically admissible states of the system. For most values of the total mass frozen into a given bowed field, force-balance and steady energy-transport cannot both be met without a finite fraction of the total mass having collapsed into a cold sheet of zero thickness, within which the frozen-in condition must break down. An exact, resistive hydromagnetic extension of the Kippenhahn-Schl\"{u}ter slab is also presented, resolving the mass-sheet singularity into a finite-thickness layer of steadily-falling dense fluid. Our hydromagnetic result suggests that the narrow, vertical prominence HαH_{\alpha} threads may be falling across magnetic fields, with optically-thick cores much denser and ionized to much lower degrees than conventionally considered. This implication is discussed in relation to (i) the recent {\it SDO/AIA} observations of quiescent prominences that are massive and yet draining mass everywhere in their interiors, (ii) the canonical range of 5−60G5-60 G determined from spectral-polarimetric observations of prominence magnetic fields over the years and (iii) the need for a more realistic multi-fluid treatment.Comment: 45 pages, 14 figure

    Using GPS-enabled cell phones to track the travel patterns of adolescents

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    <p>Abstract</p> <p>Background</p> <p>Few tools exist to directly measure the microsocial and physical environments of adolescents in circumstances where participatory observation is not practical or ethical. Yet measuring these environments is important as they are significantly associated with adolescent health-risk. For example, health-related behaviors such as cigarette smoking often occur in specific places where smoking may be relatively surreptitious.</p> <p>Results</p> <p>We assessed the feasibility of using GPS-enabled cell phones to track adolescent travel patterns and gather daily diary data. We enrolled 15 adolescent women from a clinic-based setting and asked them to carry the phones for 1 week. We found that these phones can accurately and reliably track participant locations, as well as record diary information on adolescent behaviors. Participants had variable paths extending beyond their immediate neighborhoods, and denied that GPS-tracking influenced their activity.</p> <p>Conclusion</p> <p>GPS-enabled cell phones offer a feasible and, in many ways, ideal modality of monitoring the location and travel patterns of adolescents. In addition, cell phones allow space- and time-specific interaction, probing, and intervention which significantly extends both research and health promotion beyond a clinical setting. Future studies can employ GPS-enabled cell phones to better understand adolescent environments, how they are associated with health-risk behaviors, and perhaps intervene to change health behavior.</p

    Five More Massive Binaries in the Cygnus OB2 Association

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    We present the orbital solutions for four OB spectroscopic binaries, MT145, GSC 03161-00815, 2MASS J20294666+4105083, and Schulte 73, and the partial orbital solution to the B spectroscopic binary, MT372, as part of an ongoing study to determine the distribution of orbital parameters for massive binaries in the Cygnus OB2 Association. MT145 is a new, single-lined, moderately eccentric (e=0.291+/-0.009) spectroscopic binary with period of 25.140+/-0.008 days. GSC 03161-00815 is a slightly eccentric (e=0.10+/-0.01), eclipsing, interacting and double-lined spectroscopic binary with a period of 4.674+/-0.004 days. 2MASS J20294666+4105083 is a moderately eccentric (e=0.273+/-0.002) double-lined spectroscopic binary with a period of 2.884+/-0.001 days. Schulte 73 is a slightly eccentric (e=0.169+/-0.009), double-lined spectroscopic binary with a period of 17.28+/-0.03 days and the first "twin" in our survey with a mass ratio of q=0.99+/-0.02. MT372 is a single-lined, eclipsing system with a period of 2.228 days and low eccentricity (e~0). Of the now 18 known OB binaries in Cyg OB2, 14 have periods and mass ratios. Emerging evidence also shows that the distribution of log(P) is flat and consistent with Oepik's Law.Comment: Accepted to Astronomical Journa
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