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  • 1
    ISSN: 1437-3262
    Keywords: Benthic-pelagic coupling ; Greenland-Norwegian Sea ; Remineralization ; Bioturbation ; Sediment accumulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The sedimentation pattern of organic material in the Greenland-Norwegian Sea is reflected in the surface sediments, although less than 0.5% of the organic matter is buried in the sediment. Maximum fluxes and benthic responses are observed during June and/or August/September, following the pattern of export production in the pelagial zone. The annual remineralization rate on the Vøring Plateau is 3.0 g C m−2 a −1 Freshly settled phytodetritus, as detected by chlorophyll measurements, is rapidly mixed into the sediment and decomposed. It stimulates the activity of benthic organisms, especially foraminifera. The mixing coefficient for this material is D b=0.2 cm2 d−1, which is two to three orders of magnitude higher than that estimated from radiotracer methods. The effect on the geological record, however, is likely to be small. Chlorophyll-containing particles are at first very evenly distributed on the seafloor. After partial decomposition and resuspension, a secondary redistribution of particles occurs which can result in the formation of a high accumulation area, with an up to 80-fold increase in the sedimentation rate by lateral advection. This is mainly due to physical processes, because biodeposition mediated by benthic animals increases sedimentation by only a factor of two or three.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 341 (1989), S. 437-439 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The investigation was carried out on the V0ring plateau off the Norwegian continental margin at a water depth of 1,430 m (67á°39'1" N, 05á°48'3" E). The station was close to an escarpment at the foot of a 200 m-high ridge, where a multiple-sample sediment trap was moored ...
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1619-7089
    Keywords: Orthopantomogram ; Orthopan tomoscintigram ; Dental bone scanning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The exact regional correlation of findings of facial bone scans, planar or SPECT, to dental orthopan X-ray films (OPT) is difficult because of the very different projection techniques. To improve correlative imaging in this regard a projection algorithm was developed that uses SPECT data of the skull for reconstructing an orthopan tomoscintigraphic projection. Fourteen conventional SPECT slices of the upper and lower jaws were obtained during bone scanning. All mandibular slices were superimposed resulting in a horseshoe shaped structure, which was marked by an ROI which was divided into segments. All 14 SPECT slices were then masked by this segmental ROI, thereby marking the teeth-carrying bone in all slices. The information from this horseshoe like ROI is then transformed into lines. Line by line arrangement results in an orthopan projection, the orthopan tomoscintigram. This new display allows 1:1 true scale superimposition with the X-ray OPT and markedly facilitates correlative imaging.
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  • 4
    ISSN: 1573-5117
    Keywords: Redox Potential ; Oxygenation ; Bioturbation ; Callianassa subterranea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A continuously recording multiple redox sensor was used to measure oxygenation effects in otherwise anoxic sediments. The sensor reacted within three minutes (increase 〉 50 mV) to oxygen penetrating into the sediment. Different patterns of oxidation/reduction were observed along burrows of sediment-dwelling infauna. Examples of an increase of more than 600 mV lasting 50 hours and short, 1 to 4 hours long, oxidation pulses of ∼ 280 mV increase are given. Redox patterns similar to the ones observed along natural burrows were generated using ‘artificial burrows’. Oxygen penetrated up to 1 mm by diffusion from burrow walls into the adjacent sediment, whereas elevated Eh values were measured within 3 mm of the burrow. The oxygenation effect of a burrowing shrimp, Callianassa subterranea, was studied in a 3-month experiment with ten sensors and five animals. For one individual we recorded 108 events with Eh increasing by more than 300 mV. It was estimated that below every square meter of sediment surface 0.7 m2. burrow surface are subjected to oxygenation at least once per day by the population of Callianassa in the southern North Sea.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2794-2801 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Alkylidenetriphenylphosphoranes, XXVIII. New Syntheses of α-Branched β-Ketocarboxylic AcidsThe reaction between acyl chlorides 1 and (1-alkoxycarbonylalkylidene)triphenylphosphoranes 2 in a molar ratio of 1:1 gives rise to the formation of phosphonium chlorides 3. The electrolysis of these phosphonium salts leads to the formation of triphenylphosphine and α-branched β-ketocarboxylic acid esters 6. The reaction between 1 and 2 in a molar ratio of 1:2 produces allenic carboxylic acid esters 8, which react with piperidine (9) to form enamines 10. Acidic hydrolysis of the latter compounds also yields the β-ketoesters 6.
    Notes: Säurechloride 1 und [1-Alkoxycarbonyl-alkyliden]-triphenylphosphorane 2 reagieren im Molverhältnis 1:1 zu Phosphoniumsalzen 3, deren Elektrolyse neben Triphenylphosphin α-verzweigte β-Keto-carbonsäureester 6 ergibt. Setzt man die aus 1 und 2 im Molverhältnis 1:2 entstehenden 8 mit Piperidin (9) um, so erhält man Enamine 10, bei deren saurer Hydrolyse ebenfalls die Verbindungen 6 entstehen.
    Additional Material: 2 Tab.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 704 (1967), S. 109-114 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Triphenylphosphin-benzylene 6 setzen sich mit Benzylhalogeniden 7 im Molverhältnis 1:1 zu Phosphoniumsalzen 8 um, die mit verdünnter Natronlauge oder bei der Elektrolyse ihrer wäßrig alkoholischen Lösung in Diaryläthane und Triphenylphosphinoxid bzw. Triphenylphosphin gespalten werden.
    Additional Material: 1 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 706 (1967), S. 68-74 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Triphenylphosphin-acyl-methylene 5 reagieren mit Bromessigsäuremethylester im Molverhältnis 2 : 1 unter C-Alkylierung und Umylidierung. Die entstehenden Triphenylphosphin-acyl-methoxycarbonylmethyl-methylene 8 werden in alkalischem Medium zu γ-Ketosäuren 10 verseift und lassen sich durch protonenkatalysierten Hofmann-Abbau in β-Acyl-acrylsäureester 14 überführen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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