25,953 research outputs found

    Vivaspin ultrafiltration: A new approach for high resolution measurements of colloidal and soluble iron species

    No full text
    Vivaspin6® ultrafiltration units with molecular weight “cut-off” membranes of 5, 10, 30, 50, and 100 kDa were used together to examine the size distribution of newly formed iron (Fe) colloids in natural seawater samples and in the presence of several different Fe chelators with varying Fe binding strength. Artificial Fe chelators, such as TAC, and 2 kDG, when added at equimolar levels to Fe, supported the formation of a continuum of Fe-ligand colloids between 5 and 100 kDa. More than 90% of the added 55Fe in these solutions occurred in Fe aggregates/particles larger than 100 kDa. The strong siderophore DFO held the majority of the added 55Fe in the “truly” soluble fraction ≤ 5 kDa, whereas 90% of 55Fe added to UV-irradiated seawater was converted into Fe colloids with a size between 50 to 100 kDa (5–6 nm). Membranes with ≥ 10 kDa showed similar “cut-off” properties on natural seawater samplescollected in the water column off the Peruvian coast. Fe solubility determined with these membranes was approximately six times greater than Fe solubility determined with the 5 kDa membrane and the 0.02 μm syringe filters. This suggests that a seamless size continuum of organic chelators (≤5 kDa–10 kDa) is present in these seawaters and that estimates of ligand production based on 0.02 μm Anotop solubility experiments underestimates the abundance of soluble/colloidal ligands. Regarding these results, we recommend the use of Vivaspin 5 kDa membranes to separate the “truly” soluble from the colloidal Fe fraction

    Author Peter FitzSimons speaking at the National Library of Australia, Canberra, 13 November 2012 /

    No full text
    Title from acquisitions documentation.; Part of the collection: Portraits of author Peter FitzSimons speaking at the National Library of Australia, Canberra, 13 November 2012.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia

    Moral Good, the Beatific Vision, and God’s Kingdom Writings by Germain Grisez and Peter Ryan, S.J.. Edited by Peter J. Weigel

    No full text
    For close to half a century, the work of Germain Grisez has been highly influential, and his writings continue to receive considerable attention from philosophers and theologians of diverse viewpoints. His co-author for this work is the professor and noted moral theologian Fr. Peter Ryan, S.J., currently the executive director of the Secretariat of Doctrine and Canonical Affairs of the United States Conference of Catholic Bishops (USCCB). These two eminent scholars explore fundamental questions about Christian eschatology, moral theory, the purpose of human life, and the promise of human fulfilment. The authors examine Christian teaching on the final destiny of persons, investigating the meaning of God's kingdom, the hope of the beatific vision, and the centrality of moral goodness and divine grace in one's final end. This work is an ideal source for students, scholars, ministers and lay persons interested in basic questions of Christian theology, the philosophy of religion, ethical theory, and Catholic doctrin

    Murder on the mountain: author talk with Peter J. Wosh

    No full text
    Author talk by Peter J. Wosh on May 5th, 2022, on his book, "Murder on the Mountain: crime, passion, and punishment in gilded age New Jersey.

    Identifying the processes controlling the distribution of H2O2 in surface waters along a meridional transect in the eastern Atlantic

    No full text
    Hydrogen peroxide (H2O2) is an important oxidant for many bio?relevant trace metals and organic compounds and has potential as a tracer for mixing in near surface waters. In this study we combine H2O2 and bio?optical measurements with satellite data for a meridional transect from 46°N to 26°S in the eastern Atlantic in order to determine the key processes affecting its distribution. Surface H2O2 ranged from 21–123 nmol L?1, with maximum inventories (0–200 m) of 5.5–5.9 mmol m?2 found at 30°N and 25°S. Analyses showed a strong positive correlation of surface H2O2 with daily irradiances and recent precipitation, though poor correlations with CDOM suggest sunlight is the limiting reactant for H2O2 formation. Vertical distributions of H2O2 were controlled by a combination of mixing processes and phytoplankton activity. The present study highlights processes controlling global H2O2 distributions and points towards the development of parameterization schemes for prediction via satellite data

    Lunchtime Talk with Author and Attorney Peter Godwin

    No full text
    Author and attorney Peter Godwin gave a lunchtime talk about the topics discussed in his book, The Fear, which focuses on the human rights situation in Zimbabwe under the rule of Robert Mugabe

    An essay about the Francis Paudras Collection on Bud Powell by Peter Pullman

    No full text
    This is an essay about the Francis Paudras Collection on Bud Powell written by Peter Pullman, a jazz scholar and author of Wail: The Life of Bud Powell (Brooklyn: Bop Changes, 2012).One image file (pdf)This project was supported by a Recordings at Risk grant from the Council on Library and Information Resources (CLIR). The grant program is made possible by funding from The Andrew W. Mellon Foundation

    Professor Peter Singer speaking at the National Press Club Canberra, 11 February 2009 [picture] /

    No full text
    Title devised by cataloguer based on information from acquisitions documentation.; Part of the collection: Humanitarian author Professor Peter Singer at the National Press Club, Canberra, 11 February 2009.; Acquired in digital format; access copy available online.; Mode of access: Internet via World Wide Web.; Photographed by a staff member of the National Library of Australia, 2009

    Controls on seawater Fe(III) solubility in the Mauritanian upwelling zone

    No full text
    Iron solubility measurements in the Mauritanian upwelling and the adjacent Open Ocean of the Tropical Atlantic show for all stations lower values in the surface mixed layer than at depth below the pycnocline. We attribute this distribution to a combination of loss terms, chiefly photo-oxidation of organic ligands in the surface, and supply terms, predominantly from the release of ligands from the decomposition of organic matter. Significant correlations with pH, oxygen and phosphate for all samples below the surface mixed layer indicate that biogenic remineralisation of organic matter results in the release of iron binding ligands into the dissolved phase. The comparison of the cFe(S)/PO(4)(3-) ratio with other published data from intermediate and deep waters in the Pacific suggests an enhanced release of iron chelators in the more productive Mauritanian upwelling zone. Citation: Schlosser, C., and P.L. Croot (2009), Controls on seawater Fe(III) solubility in the Mauritanian upwelling zon

    The Peter Martyr reader

    No full text
    Accession Number: ATLA0001328116; Language(s): English; Issued by ATLA: 20080715; Publication Type: Review; Related Books/Electronic Resources: By: Vermigli, Pietro Martire, 1499-1562 Peter Martyr reader viii, 260 p. Publisher: Kirksville, Mo.: Truman State University Press, 1999. ATLA0001327874Source type: Electronic(1)http://search.ebscohost.com/login.aspx?direct=true&db=reh&AN=ATLA0001328116&loginpage=Login.asp&site=ehost-liv
    corecore