1,741,947 research outputs found
Elucidating the toxicity targets of beta-ionone on photosynthetic system of Microcystis aeruginosa NIES-843 (Cyanobacteria)
No full textIn order to explore the potential targets of toxicity of beta-ionone on the photosynthetic system of Microcystis aeruginosa, the polyphasic rise in chlorophyll a (Chl a) fluorescence transient and transcript expression for key genes in photosystem II (PSII) of M. aeruginosa NIES-843 were studied. The EC(50) value of beta-ionone on M. aeruginosa NIES-843 was found to be 21.23 +/- 1.87 mg/L It was shown that beta-Ionone stress can lead to a decrease in pigment content of M. aeruginosa NIES-843 cells, and that carotenoids were more sensitive to beta-ionone stress than Chl a. The normalized Chl a fluorescence transients were slightly decreased at 6.67 and 10 mg/L beta-ionone, but significantly increased at 15, 22.5 and 33.75 mg/L There was no significant variation on transcript expression of psbA and psbO at a concentration of 6.67 mg/L beta-ionone. but they were down-regulated at 22.5 mg/L Ultrastructural examination by transmission electron microscopy indicated that the thylakoids were distorted, and the thylakoid membrane stacks began to collapse when M. aeruginosa NIES-843 was exposed to beta-ionone at a concentration of 22.5 and 33.75 mg/L Our results indicate that the reaction centre of PS II and the electron transport at the acceptor side of PS II are the targets responsible for the toxicity of beta-ionone on the PS II of M. aeruginosa NIES-843. (C) 2011 Elsevier B.V. All rights reserved
Geochemistry of altered phases, basalts and sediments of ODP Site 136-843
No full text40Ar-39Ar incremental heating experiments on a relatively unaltered basalt from Site 843 yield a crystallization age of 110 ± 2 Ma for the central Pacific Ocean igneous basement near Hawaii. Previous estimates of the age of the basement inferred by indirect methods and from radiometric dates of the South Hawaiian Seamounts are too young by 20-30 m.y. Phyllosilicate alteration minerals from veins in the Site 843 basalts define a Rb/Sr isochron with an age of 94.5 ± 0.5 Ma. The isochron records the last equilibration of the phyllosilicate minerals with a hydrothermal fluid at about 16 m.y. after the formation of the igneous basement. The last event recorded by calcite veins is the sealing of the crust by a sufficient thickness of sediment to impede the free circulation of seawater into the crust. The chemistry of the alteration minerals indicates the rare earth elements in the hydrothermal solutions were derived from alteration of the basalts and, furthermore, were transported in solution as metal species and carbonate complexes. Calcite with approximately seawater 87Sr/86Sr, but Sr contents too low to precipitate directly from seawater, is suggested to have formed at a late stage in the alteration history of the crust by the reaction of seawater with calcite precipitated earlier from basalt-dominated hydrothermal fluids
Kentucky bluegrass: growth, development, and seed production
No full textBulletin no. 843 Moscow, Idaho :University of Idaho, College of Agriculture, Cooperative Extension System, 2005-01-01. Author(s): Holman, John D.; Thill, Don
B.N. Dupuy 843
No full textFiche en cours d'élaboration Dernière mise à jour : 1er novembre 2014 Ms. B.N. Dupuy 843. XVIe-XVIIe siècle. Contiendrait une pièce de Mellin de Saint-Gelais, l'épitaphe de Budé. Pour citer cet article : JOUBAUD Pascal et SICARD Claire, « Description du ms. B.N. Dupuy 843 », Démêler Mellin de Saint-Gelais, Carnet de recherche Hypothèses, 1er novembre 2014 [En ligne] http://demelermellin.hypotheses.org/1757
Santa Fe (ATSF) 843
No full textA photograph print showing Santa Fe (ATSF) 843, 0-8-0, Kansas City, KS
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
843 séance. — 4 Avril 1907
No full text843 séance. — 4 Avril 1907. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, V° Série. Tome 8, 1907. pp. 146-147
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