ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Cyclotella-taxa (Bacillariophyceae) in lakes of the Alpine region and their relationship to environmental variables (1995)
    Springer
    Aquatic sciences 57 (1995), S. 360-386 
    Details
    ISSN: 1420-9055
    Keywords: Cyclotella ; diatoms ; Alpine lakes ; ordination ; weighted averaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Surface sediment diatom assemblages for 86 Alpine lakes were analysed focusing on the dominant genusCyclotella and corresponding environmental data. The range of morphological variability of theCyclotella bodanica/radiosa, C. distinguenda, C. ocellata, C. comensis andC. stelligera complexes was documented. Significance tests included in the canonical correspondence analysis (CCA) indicated that total phosphorus, conductivity and surface water temperature were significantly correlated withCyclotella taxa assemblage distribution. Numerical species optima and tolerances were calculated in respect to these significant variables using weighted averaging (WA) regression and calibration. CCA and WA were able to provide information about the environmental preferences of the various morphotypes observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00878399
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    A siliceous chrysophycean cyst-based pH transfer function for Central European lakes (1996)
    Springer
    Journal of paleolimnology 16 (1996), S. 275-321 
    Details
    ISSN: 1573-0417
    Keywords: siliceous cysts ; Chrysophyceae ; pH ; lake acidification ; ordination ; calibration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The surface sediments of 50 Central European low to high mountain, acid-sensitive lakes were examined for chrysophycean stomatocysts. One hundred and twenty sic siliceous stomatocyst morphotypes were differentiated by using scanning electron microscope (SEM), counted and illustrated (light microscopy and SEM). Canonical Correspondence Analysis (CCA) showed that pH is the most important measured variable in explaining the cyst distributions, with a strong correlation to the first axis (r2=-0.78). Simple Weighted Averaging (WA) regression and calibration was performed to generate a transfer function for lake water pH. Finally, the transfer function was evaluated by reconstructing pH for a short annually laminated and 137Cs dated core from Lake Plešné, a strongly acid lake, in the Bohemian Forest. A comparison of the measured and inferred pH values indicates that the model has good predictive power. The cyst-inferred pH and the diatom-inferred pH both indicate that pH was low during the 1970s and that the lake has experienced recovery in recent years.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00207575
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Synthesen mit aliphatischen Dialdehyden, XLII. (2,4,6-Cycloheptatrien-1-yliden)malonaldehyd (8,8-Diformylheptafulven)  -  Herstellung, Struktur und Reaktionen (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 1997-2011 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Aliphatic Dialdehydes, XLII.  -  (2,4,6-Cycloheptatrien-1-ylidene)malonaldehyde (8,8-Diformylheptafulvene)  -  Synthesis, Structure, and Reactions8,8-Diformylheptafulvene (5) was synthesized for the first time by hydride abstraction from sodium salts of(cycloheptatrienyl)malonaldehydes (2 and 3). In solution, 5 exists in a solventdependent equilibrium with its valence isomer 6. The structure of 5 was determined by means of its 1H and 13C NMR spectrum, dipole moment (5.24 D), and an X-ray analysis; its dipole moment and chemical reactivity were also estimated by MNDO calculations.  -  Reactions of 5 with electrophiles (→7) and with nucleophiles (→ 8 - 14 are described.
    Notes: 8,8-Diformylheptafulven (5) wurde zum ersten Mal hergestellt durch Hydridabstraktion aus (Cycloheptatrienyl)malonaldehyd-Natriumsalzen (2 und 3). 5 steht in Lösung mit dem Valenzisomeren 6 in einem lösungsmittelabhängigen Gleichgewicht. Die Struktur von 5 wurde durch 1H- und 13C-NMR-Spektrum, Dipolmoment (5.24 D) sowie eine Röntgenstrukturanalyse gesichert; Dipolmoment und chemische Reaktivität wurden auch durch MNDO-Berechnungen abgeschätzt. - Reaktionen von 5 mit Elektrophilen (→7) und mit Nucleophilen (→8 - 14) werden beschrieben.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519851008
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Synthesen mit aliphatischen Dialdehyden, XLI. Benzylidenmalonaldehyd  -  Herstellung, Struktur und Reaktionen (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 1987-1996 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Aliphatic Dialdehydes, XLI.  -  Benzylidenemalonaldehyde  -  Synthesis, Structure, and Reactions.Unexpectedly, the oxidation of (cycloheptatrienyl)malonaldehyde (1) with silver(I) oxide or 2,3-dichloro-5,6-dicyano-1,4-benzoquinone does not give (cycloheptatrienylidene)malonaldehyde (2), but yields the hitherto unknown benzylidenemalonaldehyde (3) which exists in equilibrium with its dimer 4. The structure of 4 was determined by means of an X-ray analysis. Addition reactions of 3 with bromine, thiophenol, the potassium salt of malonaldehyde, and 4-nitroaniline, leading to 5  -  10, are described.
    Notes: Oxidation von (Cycloheptatrienyl)malonaldehyd (1) mit Silber(I)-oxid oder 2,3-Dichlor-5,6-dicyan-1,4-benzochinon führt nicht zum (Cycloheptatrienyliden)malonaldehyd (2), sondern überraschenderweise zum Benzylidenmalonaldehyd (3), der mit seinem Dimeren 4 im Gleichgewicht steht. Die Struktur von 4 wurde durch Röntgenstrukturanalyse ermittelt. Additionsreaktionen von 3 mit Brom, Thiophenol, Malonaldehyd-Kaliumsalz und 4-Nitroanilin, die zu 5 - 10 führen, werden beschrieben.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519851007
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Synthesen mit aliphatischen Dialdehyden, XL. (2,4,6-Cycloheptatrien-1-yl)malonaldehyd - Herstellung, Struktur und Reaktionen (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 1969-1986 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Aliphatic Dialdehydes, XL. - (2,4,6-Cycloheptatrien-1-yl)malonaldehyde - Synthesis, Structure, and ReactionsTropylation of the sodium salt of malonaldehyde with cycloheptatrienylium tetrafluoroborate yielded the enolized, s-trans-configurated (2,4,6-cycloheptatrien-1-yl)malonaldehyde (1) for the first time. Reaction of 1 with anilines leads to the 3-anilino-2-propenals 3 and 4 with Fischer's base to the pentamethine cyanine dye 5, with maleic anhydride and tetracyanoethylene to the cycloadducts 6 and 7, and with bifunctional N-nucleophiles to the cycloheptatrienyl-substituted heterocycles 10 - 12. The structures of 3 and 5 were determined by means of X-ray analyses.
    Notes: Tropylierung des Malonaldehyd-Natriumsalzes mit Cycloheptatrienylium-tetrafluoroborat ergab erstmals den enolisierten, s-trans-konfigurierten (2,4,6-Cycloheptatrien-1-yl)malonaldehyd (1). Umsetzungen von 1 mit Anilinen führen zu den 3-Anilino-2-propenalen 3 und 4, mit dem Fischerbase-Quartärsalz zum Pentamethincyanin-Farbstoff 5, mit Maleinsäureanhydrid und Tetracyanethylen zu den Cycloaddukten 6 und 7, und mit bifunktionellen N-Nucleophilen zu den cycloheptatrienlylsubstituierten Heterocyclen 10 - 12. Die Struktur von 3 und 5 wurde röntgenographisch ermittelt.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519851006
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...