140 research outputs found

    Experiences with the Streptococcus mutans in Lakota Sioux (SMILeS) Study: Risk Factors for Caries in American Indian Children 0-3 Years

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    Severe Early Childhood Caries (S-ECC) is a terribly aggressive and devastating disease that is all too common in lower socio-economic children, but none more so that what is encountered in American Indian Tribes. Nationwide, approximately 27% of 2-5 year olds have decay while 62% percent of American Indian/Alaska Native children in the same age group have a history of decay (IHS 2010, NHANES 1999-2002). We have conducted a study of children from birth to 36 months of age on Pine Reservation to gain a better understanding of the variables that come into play in the development of this disease, from transmission and acquisition of Streptococcus mutans genotypes from mother to child to multiple dietary and behavioral components. This article describes how we established a direct partnership with the Tribe and the many opportunities and challenges we faced in performing this 5-year field study

    The XMM Cluster Survey: The Dynamical State of XMMXCS J2215.9-1738 at z=1.457

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    We present new spectroscopic observations of the most distant X-ray selected galaxy cluster currently known, XMMXCS J2215.9-1738 at z=1.457, obtained with the DEIMOS instrument at the W. M. Keck Observatory, and the FORS2 instrument on the ESO Very Large Telescope. Within the cluster virial radius, as estimated from the cluster X-ray properties, we increase the number of known spectroscopic cluster members to 17 objects, and calculate the line of sight velocity dispersion of the cluster to be 580+/-140 km/s. We find mild evidence that the velocity distribution of galaxies within the virial radius deviates from a single Gaussian. We show that the properties of J2215.9-1738 are inconsistent with self-similar evolution of local X-ray scaling relations, finding that the cluster is underluminous given its X-ray temperature, and that the intracluster medium contains ~2-3 times the kinetic energy per unit mass of the cluster galaxies. These results can perhaps be explained if the cluster is observed in the aftermath of an off-axis merger. Alternatively, heating of the intracluster medium through supernovae and/or Active Galactic Nuclei activity, as is required to explain the observed slope of the local X-ray luminosity-temperature relation, may be responsible.Comment: 13 pages, 6 figures, accepted for publication in Ap

    Timing of primary tooth emergence among U.S. racial and ethnic groups

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    ObjectivesTo compare timing of tooth emergence among groups of American Indian (AI), Black and White children in the United States at 12 months of age.MethodsData were from two sources – a longitudinal study of a Northern Plains tribal community and a study with sites in Indiana, Iowa and North Carolina. For the Northern Plains study, all children (n = 223) were American Indian, while for the multisite study, children (n = 320) were from diverse racial groups. Analyses were limited to data from examinations conducted within 30 days of the child’s first birthday.ResultsAI children had significantly more teeth present (Mean: 7.8, Median: 8.0) than did Whites (4.4, 4.0, P < 0.001) or Blacks (4.5, 4.0, P < 0.001). No significant differences were detected between Black and White children (P = 0.58). There was no significant sex difference overall or within any of the racial groups.ConclusionsTooth emergence occurs at a younger age for AI children than it does for contemporary White or Black children in the United States.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135387/1/jphd12154.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135387/2/jphd12154_am.pd

    The XMM Cluster Survey: Active Galactic Nuclei and Starburst Galaxies in XMMXCS J2215.9-1738 at z=1.46

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    We use Chandra X-ray and Spitzer infrared observations to explore the AGN and starburst populations of XMMXCS J2215.9-1738 at z=1.46, one of the most distant spectroscopically confirmed galaxy clusters known. The high resolution X-ray imaging reveals that the cluster emission is contaminated by point sources that were not resolved in XMM observations of the system, and have the effect of hardening the spectrum, leading to the previously reported temperature for this system being overestimated. From a joint spectroscopic analysis of the Chandra and XMM data, the cluster is found to have temperature T=4.1_-0.9^+0.6 keV and luminosity L_X=(2.92_-0.35^+0.24)x10^44 erg/s extrapolated to a radius of 2 Mpc. As a result of this revised analysis, the cluster is found to lie on the sigma_v-T relation, but the cluster remains less luminous than would be expected from self-similar evolution of the local L_X-T relation. Two of the newly discovered X-ray AGN are cluster members, while a third object, which is also a prominent 24 micron source, is found to have properties consistent with it being a high redshift, highly obscured object in the background. We find a total of eight >5 sigma 24 micron sources associated with cluster members (four spectroscopically confirmed, and four selected using photometric redshifts), and one additional 24 micron source with two possible optical/near-IR counterparts that may be associated with the cluster. Examining the IRAC colors of these sources, we find one object is likely to be an AGN. Assuming that the other 24 micron sources are powered by star formation, their infrared luminosities imply star formation rates ~100 M_sun/yr. We find that three of these sources are located at projected distances of <250 kpc from the cluster center, suggesting that a large amount of star formation may be taking place in the cluster core, in contrast to clusters at low redshift.Comment: Accepted for publication in ApJ, 16 pages, 10 figure

    Guidance to inform research recruitment processes for studies involving critically ill patients

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    Clinical research in intensive care units (ICUs) is essential for improving treatments for critically ill patients. However, invitations to participate in clinical research in this situation pose numerous challenges. Studies are frequently initiated within a narrow time window when patients are often unconscious and unable to consent. Consultations or consent discussions must therefore be held with consultees or representatives, usually the patient’s relatives. Conversations about research participation in this setting may be difficult, as relatives are often overwhelmed and may feel uneasy about making decisions on behalf of their relatives. In some circumstances, legislation allows doctors to act as consultees or representatives to enrol patients in research. However, there is little good quality evidence on UK stakeholders’ perspectives to inform how recruitment is carried out in ICU studies. The Perspectives Study collected evidence on the views of over 1400 stakeholders, including patients, relatives and healthcare practitioners, many of whom had first-hand experience of ICU treatment and research. This evidence was used to inform good practice guidance on recruitment of critically ill patients to research. Established social science methods and empirical ethics were employed to reflect the interests of stakeholders and justify recommendations. This guidance aims to bridge the gap between the legal frameworks and the realities of ICU studies and to ensure that research recruitment processes reflect the views of patients and families. Researchers and an expert Advisory Group brought different perspectives to interpreting the evidence to develop the guidance. In this article we present guidance for future ICU studies

    Host galaxy identification for supernova surveys

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    Host galaxy identification is a crucial step for modern supernova (SN) surveys such as the Dark Energy Survey (DES) and the Large Synoptic Survey Telescope (LSST), which will discover SNe by the thousands. Spectroscopic resources are limited, so in the absence of real-time SN spectra these surveys must rely on host galaxy spectra to obtain accurate redshifts for the Hubble diagram and to improve photometric classification of SNe. In addition, SN luminosities are known to correlate with host-galaxy properties. Therefore, reliable identification of host galaxies is essential for cosmology and SN science. We simulate SN events and their locations within their host galaxies to develop and test methods for matching SNe to their hosts. We use both real and simulated galaxy catalog data from the Advanced Camera for Surveys General Catalog and MICECATv2.0, respectively. We also incorporate "hostless" SNe residing in undetected faint hosts into our analysis, with an assumed hostless rate of 5%. Our fully automated algorithm is run on catalog data and matches SNe to their hosts with 91% accuracy. We find that including a machine learning component, run after the initial matching algorithm, improves the accuracy (purity) of the matching to 97% with a 2% cost in efficiency (true positive rate). Although the exact results are dependent on the details of the survey and the galaxy catalogs used, the method of identifying host galaxies we outline here can be applied to any transient survey
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