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  • 1
    Electronic Resource
    Electronic Resource
    Ferromanganese crusts as indicators for paleoceanographic events in the NE Atlantic (1996)
    Springer
    International journal of earth sciences 85 (1996), S. 567-576 
    Details
    ISSN: 1437-3262
    Keywords: Ferromanganese crusts ; Phosphatization ; Paleoceanographic events ; NE Atlantic ; Mediterranean outflow water ; Messinian salinity crisis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Hydrogenetic ferromanganese crusts reflect the chemical conditions of the sewater from which they formed. Fine-scale geochemical analysis of crust layers in combination with age determinations can therefore be used to investigate paleoceanographic changes which are recorded in geochemical gradients in the crusts. At Tropic seamount (off northwest Africa), uniform crust growth influenced by terrigenous input from the African continent occurred during approximately the past 12 Ma. Phosphatization of these crusts is minor. In contrast, crusts from Lion seamount, located between Madeira and the Portuguese coast, display a much more variable growth history. A pronounced increase in Ni, Cu, and Zn is observed in some intervals of the crusts, which probably reflects increased surface productivity. A thick older phosphatized generation occurs in many samples. Hydrographic profiles indicate that Mediterranean outflow water (MOW) may play an important role in the composition of these crusts.10Be dating of one sample confirms that the interruption of the MOW during the Messinian salinity crisis (6.2–5 Ma ago) resulted in changes in element composition. Sr-isotope dating of the apatite phase of the old crust generation has been carried out to obtain a minimum age for the older generation of Atlantic crusts and to determine whether crust phosphatization in the Atlantic can be related to phosphatization episodes recorded in Pacific crusts. The preliminary data show that the old phosphatized crust generation might be as old as approximately 30–40 Ma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02369011
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  • 2
    Electronic Resource
    Electronic Resource
    Thorium and uranium isotopes in a manganese nodule from the Peru basin determined by alpha spectrometry and thermal ionization mass spectrometry (TIMS): Are manganese supply and growth related to climate? (1996)
    Springer
    International journal of earth sciences 85 (1996), S. 577-585 
    Details
    ISSN: 1437-3262
    Keywords: Manganese nodules ; Thorium dating ; Uranium isotopes ; Peru basin ; TIMS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Thorium- and uranium isotopes were measured in a diagenetic manganese nodule from the Peru basin applying alpha- and thermal ionization mass spectrometry (TIMS). Alpha-counting of 62 samples was carried out with a depth resolution of 0.4 mm to gain a high-resolution230Thexcess profile. In addition, 17 samples were measured with TIMS to obtain precise isotope concentrations and isotope ratios. We got values of 0.06–0.59 ppb (230Th), 0.43–1.40 ppm (232Th), 0.09–0.49 ppb (234U) and 1.66–8.24 ppm (238U). The uranium activity ratio in the uppermost samples (1–6 mm) and in two further sections in the nodule at 12.5±1.0 mm and 27.3–33.5 mm comes close to the present ocean water value of 1.144±0.004. In two other sections of the nodule, this ratio is significantly higher, probably reflecting incorporation of diagenetic uranium. The upper 25 mm section of the Mn nodule shows a relatively smooth exponential decrease in the230Thexcess concentration (TIMS). The slope of the best fit yields a growth rate of 110 mm/Ma up to 24.5 mm depth. The section from 25 to 30.3 mm depth shows constant230Thexcess concentrations probably due to growth rates even faster than those in the top section of the nodule. From 33 to 50 mm depth, the growth rate is approximately 60 mm/Ma. Two layers in the nodule with distinct laminations (11–15 and 28–33 mm depth) probably formed during the transition from isotopic stage 8 to 7 and in stage 5e, respectively. The Mn/Fe ratio shows higher values during interglacials 5 and 7, and lower ones during glacials 4 and 6. A comparison of our data with data from adjacent sediment cores suggests (a) a variable supply of hydrothermal Mn to sediments and Mn nodules of the Peru basin or (b) suboxic conditions at the water sediment interface during periods with lower Mn/Fe ratios.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02369012
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  • 3
    Electronic Resource
    Electronic Resource
    Ferromanganese crusts as indicators for paleoceanographic events in the NE Atlantic (1996)
    Springer
    Geologische Rundschau 85 (1996), S. 567-576 
    Details
    ISSN: 0016-7835
    Keywords: Key words Ferromanganese crusts ; Phosphatization ; Paleoceanographic events ; NE Atlantic ; Mediterranean outflow water ; Messinian salinity crisis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Hydrogenetic ferromanganese crusts reflect the chemical conditions of the seawater from which they formed. Fine-scale geochemical analysis of crust layers in combination with age determinations can therefore be used to investigate paleoceanographic changes which are recorded in geochemical gradients in the crusts. At Tropic seamount (off northwest Africa), uniform crust growth influenced by terrigenous input from the African continent occurred during approximately the past 12 Ma. Phosphatization of these crusts is minor. In contrast, crusts from Lion seamount, located between Madeira and the Portuguese coast, display a much more variable growth history. A pronounced increase in Ni, Cu, and Zn is observed in some intervals of the crusts, which probably reflects increased surface productivity. A thick older phosphatized generation occurs in many samples. Hydrographic profiles indicate that Mediterranean outflow water (MOW) may play an important role in the composition of these crusts. 10Be dating of one sample confirms that the interruption of the MOW during the Messinian salinity crisis (6.2–5 Ma ago) resulted in changes in element composition. Sr-isotope dating of the apatite phase of the old crust generation has been carried out to obtain a minimum age for the older generation of Atlantic crusts and to determine whether crust phosphatization in the Atlantic can be related to phosphatization episodes recorded in Pacific crusts. The preliminary data show that the old phosphatized crust generation might be as old as approximately 30–40 Ma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s005310050097
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  • 4
    Electronic Resource
    Electronic Resource
    Thorium and uranium isotopes in a manganese nodule from the Peru basin determined by alpha spectrometry and thermal ionization mass spectrometry (TIMS): Are manganese supply and growth related to climate? (1996)
    Springer
    Geologische Rundschau 85 (1996), S. 577-585 
    Details
    ISSN: 0016-7835
    Keywords: Key words Manganese nodules ; Thorium dating ; Uranium isotopes ; Peru basin ; TIMS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Thorium- and uranium isotopes were measured in a diagenetic manganese nodule from the Peru basin applying alpha- and thermal ionization mass spectrometry (TIMS). Alpha-counting of 62 samples was carried out with a depth resolution of 0.4 mm to gain a high-resolution 230Thexcess profile. In addition, 17 samples were measured with TIMS to obtain precise isotope concentrations and isotope ratios. We got values of 0.06–0.59 ppb (230Th), 0.43-1.40 ppm (232Th), 0.09–0.49 ppb (234U) and 1.66–8.24 ppm (238U). The uranium activity ratio in the uppermost samples (1–6 mm) and in two further sections in the nodule at 12.5±1.0 mm and 27.3–33.5 mm comes close to the present ocean water value of 1.144±0.004. In two other sections of the nodule, this ratio is significantly higher, probably reflecting incorporation of diagenetic uranium. The upper 25 mm section of the Mn nodule shows a relatively smooth exponential decrease in the 230Thexcess concentration (TIMS). The slope of the best fit yields a growth rate of 110 mm/Ma up to 24.5 mm depth. The section from 25 to 30.3 mm depth shows constant 230Thexcess concentrations probably due to growth rates even faster than those in the top section of the nodule. From 33 to 50 mm depth, the growth rate is approximately 60 mm/Ma. Two layers in the nodule with distinct laminations (11–15 and 28–33 mm depth) probably formed during the transition from isotopic stage 8 to 7 and in stage 5e, respectively. The Mn/Fe ratio shows higher values during interglacials 5 and 7, and lower ones during glacials 4 and 6. A comparison of our data with data from adjacent sediment cores suggests (a) a variable supply of hydrothermal Mn to sediments and Mn nodules of the Peru basin or (b) suboxic conditions at the water sediment interface during periods with lower Mn/Fe ratios.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s005310050098
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  • 5
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    SLC24A5, a putative cation exchanger, affects pigmentation in zebrafish and humans (2005)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2005-12-17
    Description: Lighter variations of pigmentation in humans are associated with diminished number, size, and density of melanosomes, the pigmented organelles of melanocytes. Here we show that zebrafish golden mutants share these melanosomal changes and that golden encodes a putative cation exchanger slc24a5 (nckx5) that localizes to an intracellular membrane, likely the melanosome or its precursor. The human ortholog is highly similar in sequence and functional in zebrafish. The evolutionarily conserved ancestral allele of a human coding polymorphism predominates in African and East Asian populations. In contrast, the variant allele is nearly fixed in European populations, is associated with a substantial reduction in regional heterozygosity, and correlates with lighter skin pigmentation in admixed populations, suggesting a key role for the SLC24A5 gene in human pigmentation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lamason, Rebecca L -- Mohideen, Manzoor-Ali P K -- Mest, Jason R -- Wong, Andrew C -- Norton, Heather L -- Aros, Michele C -- Jurynec, Michael J -- Mao, Xianyun -- Humphreville, Vanessa R -- Humbert, Jasper E -- Sinha, Soniya -- Moore, Jessica L -- Jagadeeswaran, Pudur -- Zhao, Wei -- Ning, Gang -- Makalowska, Izabela -- McKeigue, Paul M -- O'donnell, David -- Kittles, Rick -- Parra, Esteban J -- Mangini, Nancy J -- Grunwald, David J -- Shriver, Mark D -- Canfield, Victor A -- Cheng, Keith C -- CA73935/CA/NCI NIH HHS/ -- EY11308/EY/NEI NIH HHS/ -- HD37572/HD/NICHD NIH HHS/ -- HD40179/HD/NICHD NIH HHS/ -- HG002154/HG/NHGRI NIH HHS/ -- HL077910/HL/NHLBI NIH HHS/ -- RR017441/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 2005 Dec 16;310(5755):1782-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Jake Gittlen Cancer Research Foundation, Department of Pathology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16357253" target="_blank"〉PubMed〈/a〉
    Keywords: African Americans/genetics ; African Continental Ancestry Group/genetics ; Alanine/genetics ; Alleles ; Amino Acid Sequence ; Animals ; Antiporters/chemistry/*genetics/physiology ; Asian Continental Ancestry Group/genetics ; Biological Evolution ; Calcium/metabolism ; European Continental Ancestry Group/genetics ; Gene Frequency ; Genes ; Genetic Variation ; Haplotypes ; Heterozygote ; Humans ; Ion Transport ; Melanins/analysis ; Melanosomes/chemistry/ultrastructure ; Mice ; Molecular Sequence Data ; Multifactorial Inheritance ; Mutation ; Pigment Epithelium of Eye/chemistry/ultrastructure ; Polymorphism, Single Nucleotide ; Selection, Genetic ; Skin Pigmentation/*genetics ; Threonine/genetics ; Zebrafish/embryology/*genetics/metabolism ; Zebrafish Proteins/chemistry/*genetics/physiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 6
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    Discrete visual defects in pearl mutant mice (1983)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1983-03-04
    Description: The mutant mouse pearl, characterized by its hypopigmentation, has a specific functional defect in a sensory system--the retina. The intact pearl mouse has reduced sensitivity in the dark-adapted condition. Normal sensitivity is restored by isolation and superfusion of the retina with bicarbonate-buffered Ringer solution, suggesting that the retinal expression of the pearl mutation depends on a diffusible substance. The pearl phenotype is described as a possible model for human congenital stationary night blindness.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Balkema, G W -- Mangini, N J -- Pinto, L H -- R01EY02536/EY/NEI NIH HHS/ -- New York, N.Y. -- Science. 1983 Mar 4;219(4588):1085-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6600521" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Dark Adaptation ; *Disease Models, Animal ; Mice ; Mice, Mutant Strains/*physiology ; Night Blindness/*genetics/physiopathology ; Retina/physiopathology ; Vision, Ocular/*physiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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