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
    Comments on the Role of H2S in the Chemistry of Earth's Early Atmosphere and in Prebiotic Synthesis (1998)
    Springer
    Journal of molecular evolution 47 (1998), S. 127-132 
    Details
    ISSN: 1432-1432
    Keywords: Key words: Prebiotic atmospheres — H2S — CO2— Sulfur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract: Free energy calculations and experimental measurements have been used to show that H2S/CO2 mixtures outgassing from a prebiotic Earth's crust would have produced a reducing gas mixture containing CO, H2, H2O, and S x as principal components. Due to rapid recombination of H2, CO, and S x to H2S and CO2 on cooling from a high temperature to ambient conditions, reducing components would have been retained only if efficient quenching of the reduced gas mixture had been possible. Consequently, subsea vents or vents with efficient infusion of water would have been ideal sites for retention of reduced species and for prebiotic organic synthesis. It is suggested that C/H/O/S ratios are important factors in controlling the degree of prebiotic organic synthesis and, hence, the emergence of life, since if oxygen is abundant, CO2 and SO2 would have been dominant species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00006369
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The CN2 Induction Algorithm (1989)
    Springer
    Machine learning 3 (1989), S. 261-283 
    Details
    ISSN: 0885-6125
    Keywords: Concept learning ; rule induction ; noise ; comprehensibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Systems for inducing concept descriptions from examples are valuable tools for assisting in the task of knowledge acquisition for expert systems. This paper presents a description and empirical evaluation of a new induction system, CN2, designed for the efficient induction of simple, comprehensible production rules in domains where problems of poor description language and/or noise may be present. Implementations of the CN2, ID3, and AQ algorithms are compared on three medical classification tasks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022641700528
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The CN2 induction algorithm (1989)
    Springer
    Machine learning 3 (1989), S. 261-283 
    Details
    ISSN: 0885-6125
    Keywords: Concept learning ; rule induction ; noise ; comprehensibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Systems for inducing concept descriptions from examples are valuable tools for assisting in the task of knowledge acquisition for expert systems. This paper presents a description and empirical evaluation of a new induction system. CN2, designed for the efficient induction of simple, comprehensible production rules in domains where problems of poor description language and/or noise may be present. Implementations of the CN2, ID3, and AQ algorithms are compared on three medical classification tasks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00116835
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Nodulation and nitrogen fixation (Acetylene reduction) in desert ironwood (Olneya tesota) (1981)
    Springer
    Oecologia 48 (1981), S. 292-293 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Acacia greggi, Cercidium floridium, and Olneya tesota seeds were inoculated with soil from beneath mature native desert trees and grown in the greenhouse on a nitrogen free media. Olneya tesota seedlings nodulated and reduced acetylene to ethylene. Nodulation or acetylene reduction was not observed in A. greggi or C. floridium. This is the first report of nodulation and nitrogen fixation in Olneya tesota.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00347980
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Benzylation of thiophene using zinc and iron chloride modified montmorillinite clay (1994)
    Springer
    Catalysis letters 25 (1994), S. 163-168 
    Details
    ISSN: 1572-879X
    Keywords: Thiophene ; benzylation ; iron/zinc chlorides ; modified montmorillinite ; Friedel-Crafts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Montmorillinite clays, modified with either Zn(II) or Fe(III) chlorides have been used to catalyze the Friedel-Crafts alkylation of thiophene. High yields (ca. 80%) of 2- and 3-benzylthiophene mixtures were obtained using either catalyst in chlorobenzene or nitrobenzene solvent at 80°C. The ratio of 2–3-products was found to be controlled by their relative stability. Reactions were most rapid in nitrobenzene solution (〈5 min) and resulted in formation of the 2-isomer as the only mono-substituted product. This is believed to be the first example in which an alkylation of thiophene has been limited to one regio-isomer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00815426
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Salinity tolerance of the tree legumes: Mesquite (Prosopis glandulosa var.torreyana, P. velutina andP. articulata) Algarrobo (P. chilensis), Kiawe (P. pallida) and Tamarugo (P. tamarugo) grown in sand culture on nitrogen-free media (1981)
    Springer
    Plant and soil 61 (1981), S. 311-317 
    Details
    ISSN: 1573-5036
    Keywords: Biofuel ; Leguminous trees ; Nitrogen fixation ; Semi-arid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Sand culture pot experiments were carried out with Proposis seedlings in the greenhouse on a nitrogen free nutrient solution with increasing levels of sodium chloride. All species tolerated a 6,000 mg/l salinity with no reduction in growth.P. velutina was the only species that poorly tolerated the 12,000 mg/l salinity level.P. articulata, P. pallida, andP. tamarugo tolerated 18,000 mg/l NaCl with little reduction in growth and grew slightly in a salinity (36,000 mg/l NaCl) greater than seawater. This is the first legume known to grown in salinities equivalent to seawater.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182012
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Position of mesquite (Prosopis spp) nodulation and nitrogen fixation (acetylene reduction) in 3-m long phraetophytically simulated soil columns (1982)
    Springer
    Plant and soil 64 (1982), S. 297-305 
    Details
    ISSN: 1573-5036
    Keywords: Drought stress ; Nitrogen fixation ; Nodulation ; Prosopis spp ; Semi-arid ; Tree legumes ; Water potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The literature does not contain a field report of nodulation for the xerophytic tree legumes of the genus Prosopis despite their widespread occurrence in semi-arid regions of the world. A phraetophytically simulated greenhouse experiment was conducted with mesquite in a 3m deep soil column to determine if nodules would form in deper depths where moisture is more abundant. The upper 0.5m in the soil column was allowed to dry to 2200 kPa but the 3.2 m depth was maintained at soil moistures more positive than 70 kPa by water additions to the bottom of the soil column. Over 100 nodules and an acetylene reduction rate of 1.9 mg/h were observed at the 3.2m depth. Nodulation or acetylene reduction were not observed closer than 2.7m from the surface. Air temperatures during these assays exceeded 45°C. Leaf xylem water potentials were in the 2800–3500 kPa range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372512
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Nitrogen fixation (acetylene reduction) and cross inoculation in 12 Prosopis (mesquite) species (1980)
    Springer
    Plant and soil 57 (1980), S. 177-186 
    Details
    ISSN: 1573-5036
    Keywords: Drought-adapted legumes ; Leguminous trees ; Rangeland improvement ; Semi-arid soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The leguminous tree mesquite (Prosopis spp) exists on millions of hectares of semi-arid regions of the world. No whole plant acetylene reductions for mesquite have been reported in the literature and nodulation has only been reported for three of the forty-four species. We report greenhouse studies in which 12Prosopis species representing African and North and South American germplasm (1) became nodulated when inoculated with rhizobia strain isolated from a North American mesquite, (2) grew on a nitrogen free nutrient media, (3) reduced acetylene to ethylene, and (4) had a positive significant correlation between the acetylene reduction rates and above ground dry matter. The capability of mesquite to fix nitrogen must now be considered firmly established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02211677
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Hypertasks (1984)
    Springer
    Synthese 〈Dordrecht〉 61 (1984), S. 387-390 
    Details
    ISSN: 1573-0964
    Source: Springer Online Journal Archives 1860-2000
    Topics: Natural Sciences in General , Philosophy
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00485061
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Welfare gains from optimization in dynamic planning models (1973)
    Springer
    Economic change & restructuring 13 (1973), S. 75-90 
    Details
    ISSN: 1574-0277
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract This paper compares the results of two multisectoral models used to plan the dynamic consistency of sectoral investment. Solution of an optimizing model forecasts a frontier of the economy's future choice set. This frontier represents a ten year welfare gain only 2 or 3 percent greater than any investment program simulated by a dynamic Leontief system. The paper explains what efficient behavior accounts for the “better” performance of the optimizing model. Developing dynamic programming models is costly in terms of data, computational complexity, man-machine interaction, and solution interpretation. Therefore, it is recommended that the lessons derived by working with the dynamic LP be applied to improve the planner's control of the less expensive input/output simulation model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00410552
    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...