3,124 research outputs found

    Hydroxyl as a Tracer of H2 in the Envelope of MBM40

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    We observed 51 positions in the OH 1667 MHz main line transitions in the translucent, high latitude cloud MBM40. We detected OH emission in 8 out of 8 positions in the molecular core of the cloud and 24 out of 43 in the surrounding, lower extinction envelope and periphery of the cloud. Using a linear relationship between the integrated OH line intensity and E(B-V), we estimate the mass in the core, the envelope, and the periphery of the cloud to be 4, 8, and 5 solar masses. As much as a third of the total cloud mass may be found in the in the periphery (E(B-V) << 0.12 mag) and about a half in the envelope (0.12 \le E(B-V) \le 0.17 mag). If these results are applicable to other translucent clouds the OH 1667 MHz line is an excellent tracer of gas in very low extinction regions and high-sensitivity mapping of the envelopes of molecular clouds may reveal the presence of significant quantities of molecular mass.Comment: 26 pages, 3 figures, and 5 table

    A global open-source database of flood-protection levees on river deltas (openDELvE)

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    Flood-protection levees have been built along rivers and coastlines globally. Current datasets, however, are generally confined to territorial boundaries (national datasets) and are not always easily accessible, posing limitations for hydrologic models and assessments of flood hazard. Here, we bridge this knowledge gap by collecting and standardizing global flood-protection levee data for river deltas into the open-source global river delta levee data environment, openDELvE. In openDELvE, we aggregate levee data from national databases, reports, maps, and satellite imagery. The database identifies the river delta land areas that the levees have been designed to protect. Where data are available, we record the extent and design specifications of the levees themselves (e.g., levee height, crest width, construction material) in a harmonized format. The 1657 polygons of openDELvE contain 19 248 km of levees and 44 733.505 km2 of leveed area. For the 153 deltas included in openDELvE, 17 % of the land area is confined by flood-protection levees. Around 26 % of delta population lives within the 17 % of delta area that is protected, making leveed areas densely populated. openDELvE data can help improve flood exposure assessments, many of which currently do not account for flood-protection levees. We find that current flood hazard assessments that do not include levees may exaggerate the delta flood exposure by 33 % on average, but up to 100 % for some deltas. The openDELvE is made public on an interactive platform (https://www.opendelve.eu/, 1 October 2022), which includes a community-driven revision tool to encourage inclusion of new levee data and continuous improvement and refinement of open-source levee data.</p

    National Security in the Information Age: Are We Heading Toward Big Brother?

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    Symposium Welcome: Alexander McDaniel, Symposium Editor, University of Richmond Law Review, and Wendy C. Perdue, Dean of the University of Richmond School of Law. (9:00 a.m. - 9:15 a.m.) “How Does the Government Collect Data Through Surveillance?” Panel Discussion: William C. Banks, Distinguished Professor of Law at Syracuse University College of Law and Founding Director of the Institute for National Security and Counterterrorism, and Jake Laperruque, Privacy Fellow with The Constitution Project. Professor Paul D. Crane, Associate Professor at the University of Richmond School of Law, served as moderator. (9:15 a.m. - 10:30 a.m.) “How Does the Government Retain and Destroy Data?” lecture: Douglas Cox, Associate Professor at CUNY School of Law. (10:45 a.m. - 11:45 a.m.) “How Does Data Impact the Courtroom?” Panel: Lt. Colonel Jeffrey Addicott (U.S. Army, ret.), Professor of Law and Director of the Center for Terrorism Law at St. Mary’s University School of Law, and Paul Gill, Assistant Federal Public Defender for the Federal Public Defender, Eastern District of Virginia. Douglas A. Ramseur, Capital Defender with the Office of the Capital Defender in Central Virginia, served as moderator. (1:00 p.m.- 2:15 p.m.) Keynote Address: Thomas J. Ridge, former Pennsylvania Governor and the first U.S. Secretary of Homeland Security. (2:30 p.m. – 3:30 p.m.

    A study of blood contamination of Siqveland matrix bands

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    AIMS To use a sensitive forensic test to measure blood contamination of used Siqveland matrix bands following routine cleaning and sterilisation procedures in general dental practice. MATERIALS AND METHODS: Sixteen general dental practices in the West of Scotland participated. Details of instrument cleaning procedures were recorded for each practice. A total of 133 Siqveland matrix bands were recovered following cleaning and sterilisation and were examined for residual blood contamination by the Kastle-Meyer test, a well-recognised forensic technique. RESULTS: Ultrasonic baths were used for the cleaning of 62 (47%) bands and retainers and the remainder (53%) were hand scrubbed prior to autoclaving. Overall, 21% of the matrix bands and 19% of the retainers gave a positive Kastle-Meyer test, indicative of residual blood contamination, following cleaning and sterilisation. In relation to cleaning method, 34% of hand-scrubbed bands and 32% of hand-scrubbed retainers were positive for residual blood by the Kastle-Meyer test compared with 6% and 3% respectively of ultrasonically cleaned bands and retainers (P less than 0.001). CONCLUSIONS: If Siqveland matrix bands are re-processed in the assembled state, then adequate pre-sterilisation cleaning cannot be achieved reliably. Ultrasonic baths are significantly more effective than hand cleaning for these items of equipment

    Mallard Duckling Growth and Survival in Relation to Aquatic Invertebrates

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    Identification and assessment of the relative importance of factors affecting duckling growth and survival are essential for effective management of mallards on breeding areas. For each of 3 years (1993-95), we placed Fl-generation wild mallard (Anas platyrhynchos) females on experimental wetlands and allowed them to mate, nest, and rear broods for 17 days. We manipulated invertebrate densities by introducing fathead minnows (Pimephales promelas) at high densities in half of the wetlands on which broods were confined. Day- 17 body mass of surviving ducklings (n = 183) was greater for ducklings that were heavier at hatch; the difference averaged 1.7 g at day 17 for each 1.0 g at hatch (P = 0.047). Growth ratio (the proportion of body mass attained by ducklings when they were last measured relative to that predicted for wild female mallard ducklings) also was positively related to body mass at hatch (P = 0.004). Mean day-17 body mass and mean growth ratio of ducklings per brood (each adjusted for body mass at hatch) were positively related to numbers of aquatic invertebrates (Ps \u3c 0.001) and negatively related to variance in the daily minimum air temperature during the exposure period (Ps \u3c 0.020). Early growth of mallards was more sensitive to variation in numbers of invertebrates than to air temperature or biomass of invertebrates. Duckling survival was positively related to growth ratio (P \u3c 0.001). Our study provides parameter estimates that are essential for modeling growth and survival of mallard ducklings. We emphasize the need for conserving brood-rearing wetlands in the Prairie Pothole Region that are capable of supporting high densities of aquatic invertebrates

    embCAB Sequence Variation Among Ethambutol-Resistant Mycobacterium Tuberculosis Isolates Without embB306 Mutation

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    Mechanisms of resistance to ethambutol in Mycobacterium tuberculosis remain inadequately described. Although there is mounting evidence that mutations of codon 306 in embB play a key role, a significant number of phenotypically ethambutol-resistant strains do not carry mutations in this codon. Here, other mutations in the embCAB operon are suggested to be involved in resistance development
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