16,870 research outputs found

    Interim report on the ground-water resources of Seminole County, Florida

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    Salt-water encroachment is undoubtedly the problem of most concern to users of ground water in Florida. This is a problem in many coastal areas where water levels are lowered excessively by heavy pumping. It is a problem also in some inland areas where the water-bearing formations contain salty water at relatively shallow depths. Among the coastal areas where wells have become contaminated with salt water are Pinellas County and the Miami area of Dade County. Inland areas where wells are likely to become contaminated with salt water include Seminole County and the southwestern part of Volusia County. The purpose of the investigation is to make a detailed study of the geology and ground-water resources of the county with special emphasis on the problems associated with declining water levels and salt-water contamination. This report reviews briefly the progress of the investigation through February 1954. (PDF contains 43 pages.

    PCR for the detection of pathogens in neonatal early onset sepsis.

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    BACKGROUND: A large proportion of neonates are treated for presumed bacterial sepsis with broad spectrum antibiotics even though their blood cultures subsequently show no growth. This study aimed to investigate PCR-based methods to identify pathogens not detected by conventional culture. METHODS: Whole blood samples of 208 neonates with suspected early onset sepsis were tested using a panel of multiplexed bacterial PCRs targeting Streptococcus pneumoniae, Streptococcus agalactiae (GBS), Staphylococcus aureus, Streptococcus pyogenes (GAS), Enterobacteriaceae, Enterococcus faecalis, Enterococcus faecium, Ureaplasma parvum, Ureaplasma urealyticum, Mycoplasma hominis and Mycoplasma genitalium, a 16S rRNA gene broad-range PCR and a multiplexed PCR for Candida spp. RESULTS: Two-hundred and eight samples were processed. In five of those samples, organisms were detected by conventional culture; all of those were also identified by PCR. PCR detected bacteria in 91 (45%) of the 203 samples that did not show bacterial growth in culture. S. aureus, Enterobacteriaceae and S. pneumoniae were the most frequently detected pathogens. A higher bacterial load detected by PCR was correlated positively with the number of clinical signs at presentation. CONCLUSION: Real-time PCR has the potential to be a valuable additional tool for the diagnosis of neonatal sepsis

    Upward Three-Dimensional Grid Drawings of Graphs

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    A \emph{three-dimensional grid drawing} of a graph is a placement of the vertices at distinct points with integer coordinates, such that the straight line segments representing the edges do not cross. Our aim is to produce three-dimensional grid drawings with small bounding box volume. We prove that every nn-vertex graph with bounded degeneracy has a three-dimensional grid drawing with O(n3/2)O(n^{3/2}) volume. This is the broadest class of graphs admiting such drawings. A three-dimensional grid drawing of a directed graph is \emph{upward} if every arc points up in the z-direction. We prove that every directed acyclic graph has an upward three-dimensional grid drawing with (n3)(n^3) volume, which is tight for the complete dag. The previous best upper bound was O(n4)O(n^4). Our main result is that every cc-colourable directed acyclic graph (cc constant) has an upward three-dimensional grid drawing with O(n2)O(n^2) volume. This result matches the bound in the undirected case, and improves the best known bound from O(n3)O(n^3) for many classes of directed acyclic graphs, including planar, series parallel, and outerplanar

    The utility of twins in developmental cognitive neuroscience research: How twins strengthen the ABCD research design

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    The ABCD twin study will elucidate the genetic and environmental contributions to a wide range of mental and physical health outcomes in children, including substance use, brain and behavioral development, and their interrelationship. Comparisons within and between monozygotic and dizygotic twin pairs, further powered by multiple assessments, provide information about genetic and environmental contributions to developmental associations, and enable stronger tests of causal hypotheses, than do comparisons involving unrelated children. Thus a sub-study of 800 pairs of same-sex twins was embedded within the overall Adolescent Brain and Cognitive Development (ABCD) design. The ABCD Twin Hub comprises four leading centers for twin research in Minnesota, Colorado, Virginia, and Missouri. Each site is enrolling 200 twin pairs, as well as singletons. The twins are recruited from registries of all twin births in each State during 2006–2008. Singletons at each site are recruited following the same school-based procedures as the rest of the ABCD study. This paper describes the background and rationale for the ABCD twin study, the ascertainment of twin pairs and implementation strategy at each site, and the details of the proposed analytic strategies to quantify genetic and environmental influences and test hypotheses critical to the aims of the ABCD study. Keywords: Twins, Heritability, Environment, Substance use, Brain structure, Brain functio

    Physicality and Cooperative Design

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    CSCW researchers have increasingly come to realize that material work setting and its population of artefacts play a crucial part in coordination of distributed or co-located work. This paper uses the notion of physicality as a basis to understand cooperative work. Using examples from an ongoing fieldwork on cooperative design practices, it provides a conceptual understanding of physicality and shows that material settings and co-worker’s working practices play an important role in understanding physicality of cooperative design

    Can a galaxy redshift survey measure dark energy clustering?

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    (abridged) A wide-field galaxy redshift survey allows one to probe galaxy clustering at largest spatial scales, which carries an invaluable information on horizon-scale physics complementarily to the cosmic microwave background (CMB). Assuming the planned survey consisting of z~1 and z~3 surveys with areas of 2000 and 300 square degrees, respectively, we study the prospects for probing dark energy clustering from the measured galaxy power spectrum, assuming the dynamical properties of dark energy are specified in terms of the equation of state and the effective sound speed c_e in the context of an adiabatic cold dark matter dominated model. The dark energy clustering adds a power to the galaxy power spectrum amplitude at spatial scales greater than the sound horizon, and the enhancement is sensitive to redshift evolution of the net dark energy density, i.e. the equation of state. We find that the galaxy survey, when combined with Planck, can distinguish dark energy clustering from a smooth dark energy model such as the quintessence model (c_e=1), when c_e<0.04 (0.02) in the case of the constant equation of state w_0=-0.9 (-0.95). An ultimate full-sky survey of z~1 galaxies allows the detection when c_e<0.08 (0.04) for w_0=0.9 (-0.95). We also investigate a degeneracy between the dark energy clustering and the non-relativistic neutrinos implied from the neutrino oscillation experiments, because the two effects both induce a scale-dependent modification in the galaxy power spectrum shape at largest spatial scales accessible from the galaxy survey. It is shown that a wider redshift coverage can efficiently separate the two effects by utilizing the different redshift dependences, where dark energy clustering is apparent only at low redshifts z<1.Comment: 14 pages, 7 figures; minor changes to match the published versio

    New Methods in Creating Transdisciplinary Science Policy Research Agendas: The Case of Legislative Science Advice

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    In transdisciplinary fields such as science policy, research agendas do not evolve organically from within disciplines but instead require stakeholders to engage in active co-creation. ‘Big questions’ exercises fulfill this need but simultaneously introduce new challenges in their subjectivity and potential bias. By applying Q methodology to an exercise in developing an international collaborative research agenda for legislative science advice (LSA), we demonstrate a technique to illustrate stakeholder perspectives. While the LSA international respondents—academics, practitioners, and policymakers—demonstrated no difference in their research priorities across advisory system roles, the analysis by developing and developed nation status revealed both common interests in institutional- and systems-level research and distinct preferences. Stakeholders in developing nations prioritized the design of advisory systems, especially in low- and middle-income countries, while those in developed countries emphasized policymaker evidence use. These differences illustrate unique regional research needs that should be met through an international agenda for LSA
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