ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Springer  (43)
  • 2000-2004  (34)
  • 1970-1974  (9)
  • 1955-1959
Collection
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical programming 7 (1974), S. 351-367 
    ISSN: 1436-4646
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract This paper addresses the problem of selecting the parameter in a family of algorithms for unconstrained minimization known as Self Scaling Variable Metric (SSVM) Algorithms. This family, that has some very attractive properties, is based on a two parameter formula for updating the inverse Hessian approximation, in which the parameters can take any values between zero and one. Earlier results obtained for SSVM algorithms apply to the entire family and give no indication of how the choice of parameter may affect the algorithm's performance. In this paper, we examine empirically the effect of varying the parameters and relaxing the line-search. Theoretical consideration also leads to a switching tule for these parameters. Numerical results obtained for the SSVM algorithm indicate that with proper parameter selection it is superior to the DFP algorithm, particularly for high-dimensional problems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Extremophiles 4 (2000), S. 35-41 
    ISSN: 1433-4909
    Keywords: Key words Halocins ; Halobacteria ; Salterns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Many representatives of the family Halobacteriaceae ("halobacteria") excrete halophilic bacteriocins (halocins) that inhibit the growth of other halobacteria. In spite of the fact that halocin production is widespread among the Halobacteriaceae, no information is available on their ecological significance. To test whether halocins may play a role in the interspecies competition between dif-ferent types of halobacteria in saltern crystallizer ponds inhabited by dense communities of these red halophiles, we assayed for halocins active against a variety of halobacteria in salterns from different locations worldwide. Detection of halocin activity was based on the inhibition of growth of indicator organisms on agar plates, the decreased incorporation of radiolabeled substrates, and microscopic examinations. No halocin activity was detected in any of the brines examined, in spite of the fact that halocin production was demonstrated in cultures of most microorganisms isolated from these brines. Thus, the contribution of halocins in the competition between different halobacteria in hypersaline aquatic environments is probably negligible.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1433-4909
    Keywords: Key words Solar salterns ; Halophilic Archaea ; Halophilic Bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The whole community pigments and lipids have been examined during a 5-year period in two commercial solar salterns located in the United States and in Israel. There were significant differences in the complexity of the lipid and pigment patterns within the California saltern system, and these differences were not consistent over the sampling period despite examination of ponds with the same salinity. The solar saltern system in Eilat, Israel, showed greater consistency during this sampling period and compared directly with previous studies. The complexity of the saltern in Newark, California, could be explained on the basis of the prevailing weather conditions (cooler and more rainfall) and the nutrient-enriched source water. The Eilat saltern, however, has an oligotrophic water source and has a considerably warmer and drier climate. This difference resulted in more diverse and more complex pigment and lipid patterns and presumably microbial populations in the Newark, California, plant than in the saltern in Eilat, Israel.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Space science reviews 13 (1972), S. 560-560 
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Policy sciences 33 (2000), S. 55-71 
    ISSN: 1573-0891
    Source: Springer Online Journal Archives 1860-2000
    Topics: Political Science , Economics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1432-1939
    Keywords: Key words  Pinus taeda ; Xylem cavitation ; Soil water transport ; Root-shoot relations ; Stomatal regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We analyzed the hydraulic constraints imposed on water uptake from soils of different porosities in loblolly pine (Pinus taeda L.) by comparing genetically related and even-aged plantations growing in loam versus sand soil. Water use was evaluated relative to the maximum transpiration rate (E crit) allowed by the soil-leaf continuum. We expected that trees on both soils would approach E crit during drought. Trees in sand, however, should face greater drought limitation because of steeply declining hydraulic conductivity in sand at high soil water potential (Ψ S). Transport considerations suggest that trees in sand should have higher root to leaf area ratios (A R:A L), less negative leaf xylem pressure (Ψ L), and be more vulnerable to xylem cavitation than trees in loam. The A R:A L was greater in sand versus loam (9.8 vs 1.7, respectively). This adjustment maintained about 86% of the water extraction potential for both soils. Trees in sand were more deeply rooted (〉1.9 m) than in loam (95% of roots 〈0.2 m), allowing them to shift water uptake to deeper layers during drought and avoid hydraulic failure. Midday Ψ L was constant for days of high evaporative demand, but was less negative in sand (–1.6 MPa) versus loam (–2.1 MPa). Xylem was more vulnerable to cavitation in sand versus loam trees. Roots in both soils were more vulnerable than stems, and experienced the greatest predicted loss of conductivity during drought. Trees on both soils approached E crit during drought, but at much higher Ψ S in sand (〈–0.4 MPa) than in loam (〈–1.0 MPa). Results suggest considerable phenotypic plasticity in water use traits for P. taeda which are adaptive to differences in soil porosity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 17 (1972), S. 4-6 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Canary Current region off West Africa was examined for its temperature, salinity and dissolved oxygen relations. When historical data on dissolved silicate were examined in the same area, it was found that the area of intensive upwelling has the least amounts of silicate compared with adjacent regions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract While examining historical data on dissolved oxygen in the Canary Current area and the Central Atlantic Ocean (areas of activity of the UNDP/FAO Regional Fisheries Survey in West Africa), a quite different pattern of distribution was found in the dissolved oxygen/water temperature relationship in two adjacent Marsden squares (MS)1, 074 and 038. Not only were the dissolved oxygen values in MS 038 considerably lower than in MS 074 but, in the former square, the oxgen/temperature distribution showed 2 dissolved oxygen minima, the latter only 1 minimum. In MS 335, situated below the Equator, near the African coast, the oxygen/temperature distribution differs from the two former squares in that the dissolved oxygen value decreased steadily, and no oxygen minimum was found down to a depth where the water temperature was 6°C.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Based on historical oceanographic data supplied by the National Oceanographic Data Center (NODC), Washington, D.C., USA, temperature salinity (T/S) diagrams were drawn for a large number of one-degree squares within marsden Squares (MS) 074, 038 and the northern half of MS 002. The shelf area of these squares was the area of the Regional Fisheries Survey activities in 1969 and 1970. The aim of the work is to illustrate the different characteristics of the water in the area. It is shown, in a set of diagrams, that the northern part of MS 074 contains nearly pure North Atlantic Central Water (NACW), except for the surface layer, where the characteristics change with season. In the upwelling area of Senegambia, during the upwelling season, the water is of a South Atlantic Central Water (SACW) and NACW mixed type, while in the offshore area it is nearly pure NACW. In the southern part of MS 074 and the northern part of MS 038, the subsurface water is a mixture of NACW and SACW, which changes into pure SACW southwards, but remains a mixture in medium depths. The SACW is always superimposed on the NACW. Inshore, the water mass changes with season. During the rainy season this is Liberian surface water of low salinity and high temperature. In MS 002, to the south, offshore, the subsurface water becomes pure SACW, which in deep parts overlays the Antarctic Water. Inshore at the surface, the water is desalinated during the rainy season. The Liberian surface water spreads over the whole of MS 002, nearly 1000 miles offshore.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 10 (1971), S. 30-33 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The International Biological Programme/Marine Productivity Section (IBP/PM) initiated cooperation in world-wide studies on the grey mullet; grey mulltests are of great economic importance in many places in the world, but mainly in the tropical and subtropical regions. The aim of IBP/PM is the intensification of studies and the use of lagoons and estuaries for fish production. The importance of the mullet lies also in the fact that it is a detritus feeder, a fast growing fish, and can be successfully bred under artificial conditions. To make cultivation of these fish economical and independent of natural supply (which is becoming ever more unreliable through pollution of laggons and coastal waters), the life cycle of these fish has to be completed and the problem of induced spawning solved. Such investigations are underway in several laboratories in the World. Dissemination of the knowledge acquired, accumulation of experience on this subject, and eventual use of the results as models for induced spawning and cultivation of other species of fish and invertebrates, is another aim of IBP/PM.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...