Library

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
    Induction of Triploidy and Tetraploidy in Nile Tilapia, Oreochromis niloticus (L.) (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 30 (1999), S. 0 
    Details
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract.— Induction of triploidy and tetraploidy in Nile tilapia, Oreochromis niloticus, was investigated by heat shock, cold shock, hydrostatic pressure, and/or chemicals (cytochalasin A, B, and D). Additionally, efficacy of combined protocols was determined. Heat shock 10 min after fertilization induced triploidy when incubation temperature was 24 C but not when incubation temperature was 31 C. Heat shock of 40–41 C at 4–6 min after fertilization was effective in inducing up to 100% triploidy with hatchability similar to controls. Cold shock at 13 C for 45 min five min after fertilization induced 85–100% triploids. Heat shock and multiple heat shocking were the most effective treatments for the induction of tetraploidy. Two heat treatments of 41 C applied at 65 and 80 min after fertilization for 5 min each produced approximately 80% tetraploidy in hatched fry. Immersion of fertilized eggs in cytochalasin A, B, or D at concentrations up to 10 μg/L applied at various times and durations was ineffective in inducing triploidy or tetraploidy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-7345.1999.tb00875.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Anion incorporation and its effect on the dielectric constant and growth rate of zirconium oxides (1996)
    Springer
    Journal of applied electrochemistry 26 (1996), S. 1037-1043 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Mechanically polished zirconium electrodes were potentiodynamically polarized in phosphate buffer solutions of various pH values and in 0.5 lvl NaOH. The results show that the shape of the I-E curves is independent of the solution pH. At relatively low scan rates, oxygen gas evolution was observed. The oxide film thickness was calculated from the values of the charge consumed in the anodic process assuming 100% current efficiency for oxide formation below oxygen evolution (lower values for the current efficiency are assumed for potentials above oxygen evolution). Capacitance measurements, together with the calculated oxide thickness, were used to estimate values for the dielectric constant of the oxide. Two different values of the dielectric constant were obtained for the oxides formed in the range of potential below and above oxygen evolution. Also, higher dielectric constant values were obtained with increasing solution pH. Anion incorporation was assumed to increase the conductivity of the oxide films and, hence, decrease the dielectric constant. A two-layer structure is proposed for the anodically formed oxide on zirconium in aqueous solutions; an anion-free layer near the metal and an outer layer containing the incorporated anions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00242198
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Synthesis of 5-methylisocytidine derivatives (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 455-459 
    Details
    ISSN: 1434-4475
    Keywords: Herpes simplex virus ; Human immunodeficiency virus ; Isocytidines ; N2-alkyl-5-methyl ; Nucleosides ; convergent synthesis of ; 2-Thiouridine ; 5,S2-dimethyl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung N2-substituierte 5-Methylisocytidin-Derivate wurden ausgehend von S2-Methyl-2-thiothymidin entweder durch direkte Substitution der Methylthiogruppe durch eine Aminogruppe und anschließende Kondensation mit 1,2,3,5-tetra-O-Acetyl-β-D-ribofuranose zum acetylierten Nucleosid oder umgekehrt durch Synthese eines acetylierten 5,S2-Dimethyl-2-thiouridins und nachfolgende Behandlung mit dem entsprechenden Amin hergestellt.
    Notes: Summary N2-Substituted 5-methylisocytidine derivatives were synthesized from S2-methyl-2-thiothymine either by direct substitution of the methylthio group by an amino group and subsequent condensation with 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose to give the acetylated nucleoside or by the opposite sequence first preparing an acetylated 5,S2-dimethyl-2-thiouridine followed by treatment with the appropriate amine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00810888
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Petrogenesis of the Wadi Dib alkaline ring complex, Eastern Desert of Egypt (1999)
    Springer
    Mineralogy and petrology 65 (1999), S. 249-275 
    Details
    ISSN: 1438-1168
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Der Wadi Dib-Komplex ist die älteste bekannte Ringstruktur im ägyptischen Teil des Panafrikanischen Orogengürtels. Rb-Sr Isotopendaten von sieben Proben ergeben ein vendisches Alter von 578±16 Ma and ein initiales87Sr/86Sr-Verhältnis von 0,7048±0,0010. Der magmatische Komplex besitzt einen Durchmesser von 2 km und hat am Schnittpunkt zweier Störungen innerhalb panafrikanischer Granodiorite Platz genommen. Er weist eine konzentrische Zonierung mit mehreren syenitischen äußeren Ringen, einem vorwiegend trachytischen mittleren Ring und einem quarzsyenitischen inneren Ring mit einem granitischen Kern auf; die relativen Alter der Gesteine nehmen vom Rand zurn Kern hin ab. Mineralogische and chemische Charakteristika sind die von Intraplatten- (A-Typ-) Komplexen. Haupt- and Spurenelementmuster weisen auf eine ko-magmatische Entstehung hin, zeigen aber eine Entwicklung in drei Stadien mit mehreren magmatischen Pulsen auf. Charakteristika der Elememverteilungen sind wenig systematische Änderung in den älteren Lithologien, aber ein gerichteter Entwicklungstrend in den späten, quarzführenden Lithologien. Wir schließen, daß ein alkali-basaltisches Magma in ein tiefes oder mittleres Niveau der jungen panafrikanischen Kruste intrudierte. Differentiation erfolgte im wesentlichen durch fraktionierte Kristallisation von Olivin, Klinopyroxen, Plagioklas und Apatit. Während später Entwicklungsstadien gab es vermutlich begrenzte Assimilation von Inselbogen-Kruste. Die Platznahme erfolgte entlang von Ringbrüchen in einem subvulkanischen Stockwerk und war vermutlich mit der Bildung einer Caldera während der Platznahme der trachytischen Lithologien verbunden. Der anorogene Charakter der magmatischen Folge zeigt an, daß die panafrikanische Kruste Nordost-Afrikas zur Zeit der Platznahme der alkalischen Intrusion bereits konsolidiert war.
    Notes: Summary The Wadi Dib magmatic complex is the oldest known alkaline ring complex in the Egyptian part of the Pan-African orogenic belt. Rb-Sr isotope data for seven samples suggest a Vendian age of 578±16 Ma, and a87Sr/86Sr initial ratio of 0.7048±0.0010. The igneous complex has a diameter of 2 km and was emplaced within granodioritic Pan-African host rocks at the intersection of two faults. It shows distinct concentric compositional zoning with several syenitic outer ring sheets, a mainly trachytic intermediate ring sheet, and a quartz syenite inner ring sheet with a granitic core; relative ages decrease from margin to core. The mineralogical and chemical features are characteristic of within-plate (A-type) magmatic complexes. Major and trace element patterns underline the co-magmatic origin of the suite but indicate three stages of evolution with several pulses of emplacement. A common feature of element distribution patterns is the small systematic change in the early lithologies, but a distinct evolution trend in the late quartz-bearing rocks. We propose that an alkali-basaltic parent magma was emplaced within deep or middle levels of the juvenile Pan-African crust. Differentiation mainly occurred by fractional crystallization of olivine, clinopyroxene, plagioclase, and apatite. During the late stages of evolution, limited assimilation of island-arc magmatic rocks may have occurred. Emplacement took place along ring fractures at a subvolcanic level and was probably related with formation of a caldera during emplacement of the trachytic lithologies. The anorogenic character of the magmatic suite indicates consolidation of the Pan-African crust of NE Africa at the time of emplacement of the alkaline body.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01161963
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    On the modelling of abrasive waterjet cutting (1996)
    Springer
    The international journal of advanced manufacturing technology 12 (1996), S. 255-265 
    Details
    ISSN: 1433-3015
    Keywords: Abrasive waterjet technology ; Erosion ; Machining processes ; Material cutting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Abrasive waterjet cutting operates by the impingement of a high-velocity abrasive-laden waterjet against the workpiece. The jet is formed by mixing abrasive particles with high-velocity water in mixing tubes and is forced through a tiny sapphire orifice. The accelerated jet exiting the nozzle travels at more than twice the speed of sound and cuts as it passes through the workpiece. This cutting process is being developed as a net-shape and near-net-shape machining process for cutting many metals and hard-to-machine materials. The narrow kerf produced by the stream results in neither delimitation nor stresses along the cutting path. This new technology offers significant advantages over traditional processes for its ability to cut through most sections of dense or hard materials without the need for secondary machining, to produce contours, and to be integrated into computer-controlled systems. The abrasive waterjet cutting process involves a large number of process and material parameters which are related to the waterjet, the abrasive particles, and workpiece material. Those parameters are expected to effect the material removal rates and the depth of cut. The purpose of the present work is to propose a model which is capable of predicting the maximum depth of cut for different types of materials using different process parameters. A comparison of the results of the proposed model and the models reported in the literature is introduced along with a discussion of the limitations of those models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01239612
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Synthesis of 3′-deoxy-3′-fluoro and -3′-amino nucleosides from 2-methylthiopyrimidin-4(1H)-ones (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 979-988 
    Details
    ISSN: 1434-4475
    Keywords: Nucleosides, convergent synthesis of ; Nucleosides, 2′,3′-dideoxy-3′-fluoro ; Nucleosides, 2′,3′-dideoxy-3′-amino ; 2-Methylthiopyridin-4(1H)-one nucleosides ; Human immunodeficiency virus ; Herpes simplex virus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Methyl-2,3-didesoxy-3-fluoro-5-O-(4-phenylbenzoyl)-β-D-erythro-pentofuranosid (3) und 1,5-di-O-Acetyl-2,3-didesoxy-3-phthalimido-β-D-erythro-pentofuranose (12) wurden in Gegenwart von Trimethylsilyltriflat als Katalysator mit den silylierten 2-Methylthiopyridin-4(1H)-onen2a, b zu den entsprechenden Nucleosiden5–6 und13 kondensiert. Bei diesen Reaktionen tritt als Nebenreaktion eine Öffnung der endocyclischen C-O — Bindung auf, sodaß auch die acyclischen Nucleoside4a, b gebildet werden. Die 3′-Fluoronucleoside wurden mit NH3/MeOH entschützt, die 3′-Phthalimidonucleoside mit Methylamin in Ethanol. Letztere Reaktion resultierte in eine gleichzeitigen Substitution der Pyrimidineinheit unter Austausch der Methylthiogruppe. Das 2-Methylthioanalogon zu 3′-Desoxy-3′-fluorthymidin zeigt mäßige Aktivität gegen HIV-1.
    Notes: Summary Methyl 2,3-dideoxy-3-fluoro-5-O-(4-phenylbenzoyl)-β-D-erythro-pentofuranoside (3) as well as 1,5-di-O-acetyl-2,3-dideoxy-3-phthalimodo-β-D-erythro-pentofuranose (12) were condensed with silylated 2-methylthiopyridin-4(1H)-ones2a, b in the presence of trimethylsilyl triflate as a catalyst to produce the corresponding nucleosides5, 6, 13. In these reactions, an endocyclic cleavage of C-O in3 took place; therefore, acyclic nucleosides4a, b were also formed. All 3′-fluoro nucleosides were deprotected with NH3/MeOH; the 3′-phthalimido nucleosides were deprotected with methylamine in ethanol. The latter method resulted in a concomitant substitution reaction in the pyrimidine moiety with replacement of the methylthio group. The 2-methylthio analogue of 3′-deoxy-3′-fluorothylmidine showed moderate activity against HIV-1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807039
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Structural and optical properties of ZnSe x Te1−-x solid solutions in thin-film form (1996)
    Springer
    Applied physics 63 (1996), S. 81-86 
    Details
    ISSN: 1432-0630
    Keywords: 78.20.-e ; 81.15.-z
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Solid solutions of ZnSe x Te1−x (0. 1 ≤x ≤ 1) were synthesized by vacuum fusion of stoichiometric proportions of ZnSe and ZnTe. X-ray diffraction data revealed that they have polycrystalline cubic zinc-blende structure. The calculated unit cell lattice constant (a) for the different compositions in powder form vary linearly, with molecular fractionx following Vegard's law:a(x) = 6.165 – 0.485x. Thin films of ZnSe x Te1−x (0.1 ≤x ≤ 1) solid solutions deposited onto glass or quartz substrates by thermal evaporation in a vacuum of 10−4 Pa were found to be polycrystalline with a preferred (1 1 1) orientation. The obtained data were confirmed by electron diffraction. The optical studies showed that ZnSe x Te1−x polycrystalline films of different compositions have two direct transitions with corresponding energy gapsE g andE g +Δ so The variations in bothE g andE g +Δ so, withx indicate that ZnSe x Te1−x solid solution belongs to an amalgamation-type following quadratic equations with bowing parameters 1.251 and 1.275, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01579749
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Structural and optical properties of ZnSe x Te 1-x solid solutions in thin-film form (1996)
    Springer
    Applied physics 63 (1996), S. 81-86 
    Details
    ISSN: 1432-0630
    Keywords: PACS: 78.20. ; e; 81.15. ; z
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract.  Solid solutions of ZnSe x Te 1-x (0.1≤x≤1) were synthesized by vacuum fusion of stoichiometric proportions of ZnSe and ZnTe. X-ray diffraction data revealed that they have polycrystalline cubic zinc blende structure. The calculated unit cell lattice constant (a) for the different compositions in powder form vary linearly, with molecular fraction x following Vegard’s law: a(x)=6.165−0.485x. Thin films of ZnSe x Te 1-x (0.1≤x≤1) solid solutions deposited onto glass or quartz substrates by thermal evaporation in a vacuum of 10-4 Pa were found to be polycrystalline with a preferred (1 1 1) orientation. The obtained data were confirmed by electron diffraction. The optical studies showed that ZnSe x Te 1-x polycrystalline films of different compositions have two direct transitions with corresponding energy gaps E g and E g+ΔSO The variations in both E g and E g+ΔSO with x indicate that ZnSe x Te 1-x solid solution belongs to an amalgamation-type following quadratic equations with bowing parameters 1.251 and 1.275, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003390050355
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Interactions between 14C-labelled atrazine and the soil microbial biomass in relation to herbicide degradation (1996)
    Springer
    Biology and fertility of soils 21 (1996), S. 17-22 
    Details
    ISSN: 1432-0789
    Keywords: Atrazine ; Microbial biomass ; Herbicide degradation ; Basal respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A laboratory incubation experiment was set up to determine the effects of atrazine herbicide on the size and activity of the soil microbial biomass. This experiment was of a factorial design (0, 5, and 50 μg g−1 soil of non-labelled atrazine and 6.6×103 Bq g−1 soil of 14C-labelled atrazine) x (0, 20, and 100 μg g−1 soil of urea-N) x (pasture or arable soil with a previous history of atrazine application). Microbial biomass, measured by substrate-induced respiration and the fumigation-incubation method, basal respiration, incorporation of 14C into the microbial biomass, degradation of atrazine, and 14C remaining in soil were monitored over 81 days. The amount of microbial biomass was unaffected by atrazine although atrazine caused a significant enhancement of CO2 release in the non-fumigated controls. Generally, the amounts of atrazine incorporated into the microbial biomass were negligible, indicating that microbial incorporation of C from atrazine is not an important mechanism of herbicide breakdown. Depending on the type of soil and the rate of atrazine application, 18–65% of atrazine was degraded by the end of the experiment. Although the pasture soil had twice the amount of microbial biomass as the arable soil, and the addition of urea approximately doubled the microbial biomass, this did not significantly enhance the degradation of atrazine. This suggests that degradation of atrazine is largely independent of the size of the microbial biomass and suggests that other factors (e.g., solubility, chemical hydrolysis) regulate atrazine breakdown. A separate experiment conducted to determine total amounts of 14C-labelled atrazine converted into CO2 by pasture and arable soils showed that less than 25% of the added 14C-labelled atrazine was oxidised to 14CO2 during a 15-week period. The rate of degradation was significantly greater in the arable soil at 24%, compared to 18% in the pasture soil. This indicates that soil microbes with previous exposure to atrazine can degrade the applied atrazine at a faster rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335988
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Serial Combination of Multiple Experts: A Unified Evaluation (1999)
    Springer
    Pattern analysis and applications 2 (1999), S. 292-311 
    Details
    ISSN: 1433-755X
    Keywords: Key words: Character recognition; Generic serial framework; Multiple expert configurations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract: Multiple expert decision combination has received much attention in recent years. This is a multi-disciplinary branch of pattern recognition which has extensive applications in numerous fields including robotic vision, artificial intelligence, document processing, office automation, human-computer interfaces, data acquisition, storage and retrieval, etc. In recent years, this application area has been extended to forensic science, including the identification of individuals using measures depending on biometrics, security and other applications. In this paper, a generalised multi-expert multi-level decision combination strategy, the serial combination approach, has been investigated from the dual viewpoints of theoretical analysis and practical implementation. Different researchers have implicitly utilised various approaches based on this concept over the years in a wide spectrum of application domains, but a comprehensive, coherent and generalised presentation of this approach from both theoretical and implementation viewpoints has not been attempted. While presenting here a unified framework for serial multiple expert decision combination, it is shown that many multi-expert approaches reported in the literature can be easily represented within the proposed framework. Detailed theoretical and practical discussions of the various performance results with these combinations, analysis of the internal processing of this approach, a case study for testing the theoretical framework, issues relating to processing overheads associated with the implementation of this approach, general comments on its applicability to various task domains and the generality of the approach in terms of reevaluating previous research have also been incorporated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100440050038
    Library Location Call Number Volume/Issue/Year 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...