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  • Inorganic Chemistry  (8)
  • Freshwater adaptation  (3)
  • 1980-1984  (11)
  • 1
    ISSN: 1573-5133
    Keywords: Amazonia ; Batoidea ; Brazil ; Captive breeding ; Chondrichthyes ; Colombia ; Elasmobranchii ; Freshwater adaptation ; Growth rate ; Potamotrygonidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Observations of reproductive features and body measurements were made on wild-caught, freshwater stingrays, Potamotrygon circularis and P. motoro, from the Amazon drainage of western Brazil and southern Colombia. Further observations were made in Detroit's Belle Isle Aquarium on a captive pair of P. motoro and their descendants, which constitute the first known captive breeding colony of potamotrygonids. The gross structure and function of female and male reproductive systems are described. There is no obvious difference between those of the two species. They are aplacentally viviparous, the young being nourished in advanced stages by uterine milk secreted by trophonemata. Size at onset and completion of sexual maturation, breeding season and behavior, gestation period, litter size and sex ratios are discussed. Up to 21 proportional measurements were made on several fetal and postnatal stages of both species. Several proportional changes occur in very early fetal life, but most body proportions undergo only minor changes from advanced fetal through adult stages. A growth curve is proposed for P. motoro based on observations of the captive colony.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Environmental biology of fishes 7 (1982), S. 207-228 
    ISSN: 1573-5133
    Keywords: Batoids ; Chondrichthyes ; Costa Rica ; Elasmobranchs ; Euryhalinity ; Freshwater adaptation ; Growth rate ; Isolation of population ; Nicaragua
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Of a total of 377 Pristis perotteti tagged in the Lake Nicaragua-Río San Juan System, 214 (56.8% were recovered. Eighty were recovered at the original tagging site; four moved downstream the full length of the river; and 127 tagged at the source of the river were recovered in all parts of the lake. Only one was recovered in a different river system, 58 km down the coast from the main mouth of the Río San Juan. A life span of 30 years is suggested, with rapid growth (30–40 cm per year) in the first three years, slowing to about 4 or 5 cm per year in the later years of life. Maximum sizes collected were 384 cm for males, 429 cm for females, smaller than maximum lengths reported elsewhere. The lake sawfish are not physically landlocked, but individuals remain in fresh water for very long periods; parturition takes place in fresh water; all sizes are found in the lake; and it appears that this stock finds all of its ecological needs met in the lake. Individuals may spend all of their lives in fresh water, although, as a species, P. perotteti has not completely abandoned the sea, since some are known to occur in salt water. The Lake Nicaragua-Río San Juan sawfish are a discrete stock, with only limited gene flow with neighboring stocks. P. perotteti is farther along in its adaptation to fresh water, in being able both to osmoregulate and reproduce there, than other known euryhaline elasmobranchs, except for the African stingray, Dasyatis garouaensis, of the Niger-Benue System, and the completely adapted South American freshwater rays (family Potamotrygonidae).
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  • 3
    ISSN: 1573-5133
    Keywords: Elasmobranchii ; Euryhalinity ; Freshwater adaptation ; Dam lake ; Osmoregulation ; Central America
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The Río Bayano in eastern Panama is one of many tropical rivers in which bull sharks (Carcharhinus leucas) and largetooth sawfish (Pristis perotteti) have been known to occur. Since both species can osmoregulate in fresh water throughout life, theoretically, both could survive in landlocked situations for many years.P. perotteti reproduces in fresh water, butC. leucas ordinarily does not, so only the former would appear to have the potential for establishing a breeding stock in such a landlocked freshwater body. The damming of the Rio Bayano and the creation of a large impoundment in 1976 provides a test of the ability of members of both species trapped there to survive and to establish breeding stocks. In 1980 and 1981 three mature femaleC. leucas were found dead in Lake Bayano and three sub-adult femaleP. perotteti were taken by trammel net. These events confirm the ability of both to survive in fresh water for long periods, but the establishment of breeding stocks appears doubtful and the question may not be answered for many years.
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  • 4
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N.M.R. Spectroscopic Studies of 15N Labelled N-Phosphorylphosphazenes and Imidodiphosphoric Acid Derivatives15N labelled compounds were prepared and investigated by means of 31P- and 15N-NMR spectroscopy. The chemical shift values δP and δN, and the coupling constants 1JPN and 2JPP are discussed and interpreted qualitatively by semiempirical quantumchemical calculations (CNDO/2) using POPLE'S ΔE-model.
    Notes: 15N-markierte Verbindungen der Substitutionsreihen wurden synthetisiert und mit Hilfe der 31P- und 15N-NMR-Spektroskopie untersucht. Die chemischen Verschiebungen δP und δN sowie die Kopplungskonstanten 1JPN und 2JPP werden diskutiert und qualitativ mit Hilfe halbempirischer quantenchemischer Rechnungen (CNDO/2) im Rahmen des POPLE-schen ΔE-Modells interpretiert.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 490 (1982), S. 121-128 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: NMR Spectroscopic Studies of 15N Labelled OxocyclophosphazanesThe completely 15N labelled cyclophosphazanes (15NMeP(OMe)O)3, (15NEtP(OEt)O)3, and (15NMeP(OMe)O)4 were prepared by rearrangement of the corresponding alkoxyphosphazenes and their 31P- and 15N-NMR spectra were investigated. On the case of the trimer compounds spectra of the ABB′XX′Y spin type were obtained; all coupling constants are relevant, and like the 15N chemical shifts they are found only by means of spectra simulations. The relative signs of the coupling constants 1JPN, 2JPP, 2JNN, and 3JPN were also obtained.
    Notes: Die vollständig 15N-markierten Cyclophosphazane (15NMeP(OMe)O)3, (15NEtP(OEt)O)3 und (15NMeP(OMe)O)4 wurden aus den entsprechenden Alkoxyphosphazenen dargestellt und sowohl 31P- als auch 15N-NMR-spektroskopisch untersucht. Bei den trimeren Verbindungen wurden Spektren vom Spintyp ABB'XX'Y erhalten; alle Kopplungskonstanten sind relevant, sie können wie die 15N-chemischen Verschiebungen nur auf dem Wege der Spektrensimulation erhalten werden. Es ergeben sich auch die relativen Vorzeichen für die Kopplungskonstanten 1JPN, 2JPP, 2JNN und 3JPN.
    Additional Material: 2 Ill.
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  • 6
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 31P and 195Pt N.M.R. Investigations on Diplatinum (I) Complexes of the Type [Pt2(μ-SPR2)2L2] (L = PR3, PhP(OPh)2, P(OPh)3, CNR)31P-, 195Pt-chemical shifts and 195Pt-31P- resp. 31P-31P-coupling constants of a series of doubly bridged diplatinum(I) complexes are reported. 31P-coordination chemical shifts of the terminal ligands of complexes of type [Pt2(μ-SPR2)2(P′R3′)2] and some of the various coupling constants are strongly influenced by the π-acceptor strength of these ligands. J(195Pt-195Pt) is found to change the sign among the series of complexes investigated. Thermal singlett triplet exitation giving rise to the paramagnetism of these complexes observed by preliminary EPR-measurements and confirmed by EHT-calculations is deduced from the large values of 2J(P-P′) and 3J(P′P′) as well as the unusually high temperature dependence of some coupling constants and other NMR features. The chemical stability of the doubly bridged core, the coordination shifts of the bridging phosphorus atoms and EHT-calculations suggest a view of aromaticity of the [Pt2(μ-SPR2)2](M-M) unit of these complexes.
    Notes: Es werden 31P-, 195Pt-chemische Verschiebungen und 195Pt31P-Kopplungskonstanten einer Reihe von doppelt verbrückten Diplatin(I)-Komplexen mitgeteilt. 31P-koordinationschemische Verschiebungen der ternären Liganden von Komplexen des Typs [Pt2(μ-SPR2)2(P′R3′)2] und verschiedene Kopplungskonstanten werden stark von der π-Akzeptor-Stärke dieser Liganden beeinflußt. J(195P-195Pt) wird innerhalb der Reihe der untersuchten Komplexe mit wechselndem Vorzeichen gefunden. Aus den großen Werten von 2J(Pt-P′) und 3J(P′P′) sowie der ungewöhnlich starken Temperaturabhängigkeit einiger Kopplungskonstanten und anderen NMR-Eigenschaften wird auf Paramagnetismus dieser Komplexe aufgrund thermischer Singlett-Triplett-Anregung geschlossen, der in vorläufigen EPR-Messungen gefunden und durch EHT-Rechnungen gestützt wird. Die chemische Stabilität des doppelt verbrückten Kerns, die koordinationschemischen Verschiebungen der Brückenphosphoratome und EHT-Rechnungen weisen auf Aromatizität der [Pt2(μ-SPR2)2](M-M)-Einheit dieser Komplexe hin.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 480 (1981), S. 163-170 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: NMR Spectroscopic Studies of 15N Labelled Geminally Disubstituted CyclotriphosphazenesIt is demonstrated by means of some selected 15N labelled geminally disubstituted cyclotriphosphazenes, 15N3P3X4Y2 (X = Cl; Y = F, NH2, or SEt), as an example, that the coupling constants 1JPN may be of different signs. The absolute value of 1JPN is significantly influenced only by those substituents, which are bonded to the phosphorus nucleus directly concerned in the coupling. Also the 15N chemical shifts are only changed by substituents on directly bonded phosphorus atoms.
    Notes: Am Beispiel ausgewählter 15N-markierter geminal disubstituierter Cyclotriphosphazene, 15N3P3X4Y2 (X = Cl; Y = F, NH2, SEt), wird gezeigt, daß die Kopplungskonstanten 1JPN unterschiedliche Vorzeichen haben können. Auf die Größe von 1JPN haben nur jeweils diejenigen Substituenten einen merklichen Einfluß, die an den direkt an der Kopplung beteiligten Phosphorkern gebunden sind. Die 15N-chemischen Verschiebungen werden ebenfalls nur durch die Substituenten an unmittelbar benachbarten Phosphoratomen beeinflußt.
    Additional Material: 4 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 489 (1982), S. 126-130 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Remarks on the Evidence of Rotational Isomers in Trichlorophosphazene-N-phosphoryl-dichloride by Means of NMR SpectroscopyBy means of 31P NMR spectroscopy no rotational isomers of trichlorophosphazene-N-phosphoryldichloride are separately observable, neither in spectra of the neat compound at the immediate range of the melting temperature nor on low temperature experiments in dimethylether solution until a temperature of 158 K.
    Notes: Mit Hilfe der 31P-NMR-Spektroskopie lassen sich keine Rotationsisomere des Trichlorphosphazen-N-phosphoryldichlorids getrennt nachweisen, weder in reiner Substanz im unmittelbaren Bereich der Schmelztemperatur noch bei Tieftemperaturmessungen in Dimethylether bis zu einer Temperatur von 158 K.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 489 (1982), S. 131-138 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: NMR Spectroscopic Studies of Exocyclic 15N Labelled AmidochlorocyclotriphosphazenesSome exocyclic 15N labelled monoamidopentachlorocyclotriphosphazenes, N3P3Cl5X, and diamidotetrachlorocyclotriphosphazenes, N3P3Cl4X2, where X = 15NH2, 15NHMe, 15NMe2, or 15NHPh, were prepared, and the 31P- and 15N-NMR spectra were recorded. The chemical shift values δP and δN and the coupling constants 1JPN and 3JPN are discussed.
    Notes: Einige exocyclisch 15N-markierte Monoamidopentachlorocyclotriphosphazene, N3P3Cl5X, und Diamidotetrachlorocyclotriphosphazene, N3P3Cl4X2, wobei X = 15NH2, 15NHMe, 15NMe2 oder 15NHPh ist, wurden dargestellt und die 31P- und 15N-NMR-Spektren aufgenommen. Die chemischen Verschiebungen δP und δN und die Kopplungskonstanten 1JPN und 3JPN werden diskutiert.
    Additional Material: 2 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 465 (1980), S. 127-130 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phosphinophosphite - a Hydrolysis Product of ‘Phosphorous Suboxide, P4O’The hydrolytic degradation of polymer phosphorus suboxide, ‘P4O’ and of the P4-molecule in aqueous ethanolic sodium hydroxide leads in addition to wellknown substances to a compound containing two phosphorus atoms directly attached. By 31P-NMR spectroscopy it was identified as phosphinophosphite, [OP(O)(H)—PH2]-.
    Notes: Beim hydrolytischen Abbau des polymeren Phosphorsuboxids „P4O“ wie auch des P4-Moleküls in wäßrig-ethanolischer Natronlauge wird neben bereits bekannten Spezies eine zweikernige Phosphorverbindung gefunden, die mit Hilfe der 31P-NMR-Spektroskopie als Phosphinophosphit, [OP(O)(H)—PH2]-, identifiziert wurde.
    Additional Material: 1 Ill.
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