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  • Articles  (80)
  • growth
  • stability
  • Springer  (80)
  • Kiel: Kiel Institute for the World Economy (IfW)
  • MDPI Publishing
  • 1980-1984  (80)
  • 1
    ISSN: 1570-7458
    Keywords: Alsophila pometaria ; Geometridae ; Anisota senatoria ; Citheroniidae ; Quercus ; nutritional ecology ; herbivory ; nutritional indices ; consumption ; growth ; utilization efficiency ; nitrogen ; water ; tannins ; phenols ; gut pH ; digestive enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Alimentées sur feuillage jeune de chêne, les chenilles d'Alsophila pometaria avaient un taux relatif de croissance (RGR) et un taux relatif d'accumulation d'azote (RNAR) plus élevés que les chenilles d'Anisota senatoria alimentées sur feuillage mûr de chêne. Bien que le jeune feuillage soit plus efficacement digéré par A. pometaria (AD plus élevé), il n'est pas assimilé et utilisé pour la croissance avec de meilleurs rendements (les ECI ne sont pas différents). Ainsi le taux de croissance plus élevé d'A. pometaria est dû entièrement à un taux de consommation plus important (RCR et RNCR). Le feuillage jeune est significativement plus riche en azote et en eau que le feuillage mûr, mais les niveaux de phénol et de tanins sont les mêmes. A pometaria consomme les feuilles de différentes espèces de chênes au même taux, indépendamment de la teneur en azote, tandis que A. senatoria accroît sa consommation en réponse à une diminution de la teneur en azote. Il en résulte que le taux de croissance d'A. pometaria dépend directement de la teneur en azote des feuilles, tandis que celui d'A. senatoria en est indépendant. Les systèmes digestifs des deux insectes sont biochimiquement semblables et sont efficaces pour la digestion des protéines. Les tanins et les phénols n'influent pas sur les indices nutritionnels de ces deux espèces. Nous estimons que le principal intérêt de l'alimentation printanière est la disponibilité en feuillage succulent, riche en azote, et non l'absence de feuilles à haute teneur en tanin. L'alimentation printanière semble correspondre à une strategie alimentaire qui favorise la croissance aux dépens de l'efficacité tandis que l'alimentation en fin d'été est une stratégie qui favorise l'efficacité sur la rapidité.
    Notes: Abstract The larvae of Alsophila pometaria (Harr.), feeding on the young foliage of oak, has a higher relative growth rate (RGR) and relative nitrogen accumulation rate (RNAR) than the larvae of Anisota senatoria (J. E. Smith), feeding on the mature foliage of oak. Although the young oak foliage is more efficiently digested by A. pometaria (higher AD's), it is not more efficiently assimilated and used for growth (no difference in ECI's). Thus, the higher growth rate of A. pometaria is due entirely to a higher consumption rate (RCR and RNCR). Young foliage is significantly higher in nitrogen and water than mature foliage, but phenol and tannin levels are comparable in young and old foliage. A. pometaria consumes the foliage of different oak species at the same rate, independent of nitrogen content, while A. senatoria increases its consumption rate in response to decreased nitrogen levels. As a result, the growth rate of A. pometaria is directly related to leaf nitrogen content, while the growth rate of A. senatoria is independent of leaf nitrogen. The two species of insects have digestive systems that are very similar biochemically, and that are well-designed for effective protein digestion. Tannins and phenols do not influence the nutrional indices of either species. We suggest that the major benefit of spring feeding is the availability of succulent, high-nitrogen foliage, and not the avoidance of high-tannin foliage. The spring feeder appears to have a feeding strategy that favors rapid growth at the expense of efficiency, while the late summer feeder has a strategy that favors efficiency over rate.
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  • 2
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    Entomologia experimentalis et applicata 35 (1984), S. 75-81 
    ISSN: 1570-7458
    Keywords: Nezara viridula ; insect dietetics ; growth ; fecundity ; flight capacity ; Heteroptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les effets du régime alimentaire pendant le 5ème stade sur les performances imaginales de N. viridula ont été déterminés en comparant la croissance, la fécondité, la durée du vol captif, et l'accumulation de corps gras chez des insectes élevés sur 4 régimes stérilisés. A partir de la formation des larves de 5ème stade, elles ont été alimentées sur haricots verts et arachides, ou transférées sur un régime formé exclusivement d'arachides, ou de haricots verts, ou de graines de soja ‘trempées’, cependant la durée du 5ème stade. Les insectes ont été transférés sur un régime de haricots verts et arachides à leur émergence. Les femelles élevées continuellement de haricots verts et arachides étaient plus lourdes (P〈0,01) à l'émergence (161,6 mg) que celles élevées sur haricots verts (146,3 mg) pendant le 5ème stade, et pondent plus d'oeufs (P〈0,08) pendant une durée de 34 jours (100,9 oeufs) que celles élevées sur arachides (54,7 oeufs). Plus de femelles élevées sur haricots verts et arachides (76,2%) pondent que celles élevées sur arachides (61,1%), soja ‘trempé’ (62,5%), ou haricots verts (60,9%). Les femelles élevées sur arachides volaient plus longtemps (P 〈 0,01) (42,9 mn) que celles élevées sur haricots verts (19,8 mn) pendant des vols captifs le 3ème jour après l'émergence. 78% de toutes les femelles élevées sur arachides volaient 〉-30 mn, contre 50% pour celles élevées sur haricots verts et arachides, ou soja ‘trempé’, et 35% pour celles élevées sur haricots verts. Seulement 7% des femelles élevées sur haricots verts volaient à la 60ème minute à la fin du test, contre 25% pour les femelles soja ‘trempé’, 33% pour les femelles haricots verts et arachides, et 47% pour celles élevées sur arachides. Les femelles ont été disséquées 34 jours après l'émergence pour déterminer l'importance du corps gras. Les indices de corps gras (Kiritani, 1963) montraient que les femelles élevées sur arachides (1,8) et graines de soja (1,7) ont apparemment un corps gras plus développé que celles élevées sur haricots verts et arachides (1,5), our haricots verts (1,2), pendant le 5ème stade. Ces résultats montrent que l'alimentation pendant le dernier stade larvaire de N. viridula affecte irréversiblement la croissance, la fécondité et l'aptitude au vol des femelles. En estimant que des résultats semblables auraient été obtenus avec des insectes élevés sur ces 4 aliments depuis l'éclosion, haricots verts et arachides constituent le meilleur aliment pour l'élevage de N. viridula. Ce régime fournit une graine mûre, vraisemblablement nécessaire pour l'accumulation d'un corps gras suffisant et une aptitude au vol migratoire, et une plante verte qui fournit les aliments apparement essentiels à l'ovogenèse.
    Notes: Abstract The effects of diet during the fifth stadium on performance of adult N. viridula were determined through comparing growth, fecundity, and duration of tethered flight of insects reared on four axenic diets: fresh green bean, raw-shelled peanut, a combination of the two and soaked soybean seed. Females reared on the combination diet were heavier than those reared on green beans and oviposited more than those reared on peanuts. Three-day-old adult females reared on peanuts flew longer than those reared on green beans. More females reared on diets containing mature seed showed a capacity for extended flight and had larger fat bodies at 34-days postemergence. Thus, inadequate diet during the fifth stadium irreversibly affected growth, development, reproduction and flight capacity.
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  • 3
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    Computing 32 (1984), S. 229-237 
    ISSN: 1436-5057
    Keywords: 65L05 ; 65L07 ; Stiff system ; Rosenbroek method ; stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung In dieser Arbeit wird die Stabilität des Kaps-Rentrop-Verfahrens in die Anwesenheit nichtlinearer Steifheit (Stiffness) analysiert. Dazu werden mittels eines einfachen Modells zwei Größen introduziert. Die Werte dieser Größen reflektieren gewissermaßen das Verhalten eines Kaps-Rentrop-Verfahrens in die Anwesenheit einer bestimmten Kopplung zwischen die beiden Komponenten in das steife System gewöhnlicher Differentialgleichungen. Einige numerische Beispiele veranschaulichen die Analyse.
    Notes: Abstract In this paper we give an analysis of the effect of stiff nonlinearities on the behavior of a Kaps-Rentrop method. To that end we introduce two quantities related to a simple model. The values of these quantities determine to some extent the behavior of a Kaps-Rentrop method in case of a strong coupling between the smooth component and the transient one. Numerical examples illustrate the theoretical results.
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  • 4
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    Journal of mathematical biology 20 (1984), S. 259-276 
    ISSN: 1432-1416
    Keywords: Age-structured population dynamics ; equilibria ; stability ; bifurcation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract The existence of positive equilibrium solutions of the McKendrick equations for the dynamics of an age-structured population is studied as a bifurcation phenomenon using the inherent net reproductive rate n as a bifurcation parameter. The local existence and uniqueness of a branch of positive equilibria which bifurcates from the trivial (identically zero) solution at the critical value n=1 are proved by implicit function techniques under very mild smoothness conditions on the death and fertility rates as functional of age and population density. This first requires the development of a suitable linear theory. The lowest order terms in the Liapunov-Schmidt expansions are also calculated. This local analysis supplements earlier global bifurcation results of the author. The stability of both the trivial and the positive branch equilibria is studied by means of the principle of linearized stability. It is shown that in general the trivial solution losses stability as n increases through one while the stability of the branch solution is stable if and only if the bifurcation is supercritical. Thus the McKendrick equations exhibit, in the latter case, a standard exchange of stability with regard to equilibrium states as they depend on the inherent net reproductive rate. The derived lower order terms in the Liapunov-Schmidt expansions yield formulas which explicitly relate the direction of bifurcation to properties of the age-specific death and fertility rates as functionals of population density. Analytical and numerical results for some examples are given which illustrate these results.
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  • 5
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    Journal of mathematical biology 21 (1984), S. 25-34 
    ISSN: 1432-1416
    Keywords: Predator-prey ; density dependence ; stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract The Gurtin and Levine model5 is studied in this paper under the assumption that the fecundity of prey depends on age as well as on the total population sizes of prey and predators. The purpose of this study is to see the effect of this density dependence on the stability criteria for the equilibria of the model equations. It is shown that there are cases when, due to density dependence, the model which is originally neutrally stable becomes stable.
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  • 6
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    Bulletin of experimental biology and medicine 98 (1984), S. 1159-1161 
    ISSN: 1573-8221
    Keywords: motor response ; growth ; catecholamines
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    Topics: Biology , Medicine
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  • 7
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    Euphytica 33 (1984), S. 489-495 
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; wheat ; multilines ; recurrent parents ; stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Three multilines each of Kalyansona and PV 18 varieties of wheat were compared for their stability of yield and agronomic characters and disease resistance against the respective recurrent parents. The experiments were conducted for four years at nine locations. The multilines had more tillers and bolder seeds than the recurrent parents. There were, however, no differences for plant height, ear length and number of spikelets per spike. The genotypes x years x locations interaction was much more important than genotypes x years or genotypes x locations interaction as well as the main effects for genotypes. It is suggested that the number of test locations should be increased while decreasing the number of years. The stability parameters indicated that the multilines had a higher mean yield in the case of Kalyansona multilines whereas the yield of multilines of PV 18 was not significantly inferior to that of the recurrent parent. The regression coefficients were very close to unity except for KSML 3 (b=1.132). The deviations from regression were much larger for the multilines than for the recurrent parents. For rust resistance the multilines were superior over the varieties Kalyansona and PV 18.
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  • 8
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    Hydrobiologia 110 (1984), S. 241-245 
    ISSN: 1573-5117
    Keywords: Sudan ; pearl oyster ; feeding ; growth ; Red Sea ; Sudan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plankton samples and gut contents of P. margaritifera were analysed monthly from April 1972 to March 1973. Coscinodiscus sp. was the most ingested food by pearl oysters of all ages. However, food variety increased as the oyster grew older. Experiments confirmed the absence of food selectivity in P. margaritifera. Unlike the young ones, the adult showed reduced growth during summer (July–September), which coincides with its spawning season.
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  • 9
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    Hydrobiologia 119 (1984), S. 227-233 
    ISSN: 1573-5117
    Keywords: Ephemerella subvaria ; autochthonous ; allochthonous ; algae ; diatoms ; macrophytes ; organic matter ; diet ; growth ; survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In two laboratory tests at 15 °C early-instar nymphs of the mayfly, Ephemerella subvaria were kept on different diets and their survival and growth recorded. The diets were either conditioned maple leaf discs; maple leaf disc remnants + Gammarus faecal material; maple leaf disc remnants + Hesperophylax faecal material; a clump of Cladophora strands or periphytic growth on small stones. A control group received no food. In both the tests, nymphs kept on Cladophora showed significantly (P ⩽ 0.05 or P ⩽ 0.01) higher percentage survival than for those on any other diet and the growth of these nymphs was second only to nymphs given periphyton as a diet. Although the nymphs on a diet of periphyton showed significantly (P ⩽ 0.01) higher growth as compared to those on other food sources, the survival percentage of these nymphs was the poorest, presumably because of food limitation. As expected, a diet of maple leaf discs resulted in significantly higher survival and growth of nymphs as compared to the nymphs not given any food. The results clearly demonstrated that autochthonous sources of organic matter can serve as excellent food for stream invertebrates.
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  • 10
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    Hydrobiologia 111 (1984), S. 193-200 
    ISSN: 1573-5117
    Keywords: aquatic pressure ; aquatic macrophyte ; growth ; depth distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A method was tested for growing aquatic vascular plants at elevated hydrostatic pressure so that the influence of other factors will not mask the specific plant-pressure interaction. Eighteen species of submersed vascular plants, belonging to twelve families and several distinct growth forms, were subjected to series of hydrostatic pressures including those well in excess of those encountered by the species when growing at its normal depths in lakes. Under no circumstances was the form of the plant altered even at the highest pressures, equivalent to that at a water depth of 23 m. The removal of confounding extraneous factors depends upon controlling competing algae, on raising the pressure in a series of steps, on maintaining the pressure without fluctuations during the growing period, on suiting the light and temperature conditions to the species and maintaining aquasoil air spaces or allowing them to develop. These preliminary data suggest that the level of hydrostatic pressure in the depth distribution of aquatic plants cannot be either a necessary or a sufficient controlling factor.
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  • 11
    ISSN: 1573-5117
    Keywords: life cycles ; flight-periods ; growth ; production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The life cycle and production of Tinodes waeneri (L.) was examined at five shallow littoral localities in Lake Esrom, Denmark, during 1979/80. Five larval instars were demonstrated. The differences in temporal composition of instars indicated three different life cycles. A bivoltine strategy was shown for the most exposed locality which also had the highest average abundance equal to 11 500 ind. m−2. A univoltine population was found in the more sheltered NW part of the lake with an average density of 1 500 ind. m−2. At the three remaining stations the life cycles were partly bivoltine with wintering populations of mixed cohorts and densities between 10 500 and 3 000 ind. m−3. Two distinct flight periods with maxima in June and August were demonstrated for bi- and partly bivoltine populations. Differences in rates of growth and elimination added to the variability in life cycle. Growth rates peaked in August (5.0–7.4% d−1) at an average temperature of 20°C. Estimates of production ranged from 1.9 to 17.5 g AFDW m−2 a−1 with an average of 8.0 g AFDW m−2. The P/B ratios, which were within the expected range for uni- and bivoltine populations of trichopterans, were 5.73 for the bivoltine population and 3.31 for the univoltine population. Estimates of consumption revealed that the populations could be sustained by autochthonous epilithic production in the habitats. Variability in the quality and seasonal availability of food were judged to influence the type of life cycle.
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  • 12
    ISSN: 1573-5117
    Keywords: modeling ; growth ; tropical fishes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The growth parameters of the Von Bertalanffy equation have been computed by two methods for 24 populations of Tilapia in Malagasy lakes. The results obtained by the two technics are compared and the possible reasons of the observed differences are discussed.
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  • 13
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    Hydrobiologia 116-117 (1984), S. 276-281 
    ISSN: 1573-5117
    Keywords: seaweed ; Enteromorpha ; sewage treatment ; nutrient accumulation ; growth ; effect of salinity ; light and temperature
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  • 14
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    Hydrobiologia 116-117 (1984), S. 321-324 
    ISSN: 1573-5117
    Keywords: seaweed ; Macrocystis pyrifera ; giant kelp ; yield ; productivity ; growth ; biomass
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    Topics: Biology
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  • 15
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    Hydrobiologia 116-117 (1984), S. 383-388 
    ISSN: 1573-5117
    Keywords: seaweed ; benthic algae ; diesel oil ; growth ; recolonization
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    Topics: Biology
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  • 16
    ISSN: 1573-5117
    Keywords: Biomphalaria ; growth ; sexual maturity ; reproductive apparatus ; reproduction ; starvation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Starvation of immature snails of Biomphalaria pfeifferi and B. glabrata results in an arrest of growth and animals remain immature. Spermatogenesis is limited to spermatogonia (B.g.) or spermatocytes 1 (B.p.). The number and the size of oocytes remain inferior to that of controls. Animals show reduced genital tracts. Once feeding is restored, growth is resumed but wet weight and shell diameter do not reach the same level as in controls. Fecundity and gametogenesis do not differ from that in controls. Genital tracts weight is proportional to body weight.
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  • 17
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    Hydrobiologia 110 (1984), S. 273-279 
    ISSN: 1573-5117
    Keywords: Sudan ; Alestes ; growth ; feeding ; Nile
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The food, feeding habits and growth of 0+ Alestes nurse (Rüppel) from the Blue Nile near Khartoum, was investigated. 0+ A. nurse were observed to change their food from phytoplankton and small zooplankton during their pre-metamorphosis stages, to larger zooplankton (Daphnia spp., Chydorus sp.) and insects (larvae, pupae and imagines) during their post-metamorphosis stage. Their growth in length and weight was characterized by two distinct stanzas; during the first stanza, the fish increased in total length at a rate of 0.196 mm mm−1 wk−1, and in wet weight at a rate of 0.430 g g−1 wk−1. These rates were reduced during the second stanza to 0.046 mm mm−1 and 0.080 g g−1 wk−1, respectively. The calculated value of the exponent b in their length-weight relationship suggested that their growth was allometric.
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  • 18
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    Hydrobiologia 110 (1984), S. 295-304 
    ISSN: 1573-5117
    Keywords: Sudan ; Clarias ; breeding ; maturation ; hormones ; growth ; cultivation
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    Topics: Biology
    Notes: Abstract The seasonal abundance, population structure, reproduction, feeding, respiratory adaptations and tolerance were studied in the catfish Clarias lazera (Cuv. & Val.) in the reservoir of Jebel Aulia on the White Nile, and in the Green-Belt canals near Khartoum. Continuous monitoring of the ripe, spent and spawning females and immature fish in the population revealed that C. lazera breed synchronously in the autumn in the reservoir and rather sporadically in the canals. Medium-sized females were more fecund than old and young females. Administration of pituitary extract enhanced maturation, induced spawning in mature fish, stimulated body growth, especially in maturing specimens, and produced, as a side-effect, a diuretic response. Mature fish depended on pulmonary respiration for about 45% of the total oxygen requirement. C. lazera fed preferentially on its fry and on decayed proteinaceous food. The suitability of this species for economic cultivation is discussed.
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  • 19
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    Hydrobiologia 115 (1984), S. 105-107 
    ISSN: 1573-5117
    Keywords: aquatic Oligochaeta ; Naididae ; growth ; experimental
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The peculiarities of the growth in weight and length of Stylaria lacustris (L.) on the basis of observations in experimental vessels are considered. The growth of this species fits a parabolic curve. The equations relating weight to absolute growth rate as well as weight to duration of life are given.
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  • 20
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    Hydrobiologia 115 (1984), S. 109-112 
    ISSN: 1573-5117
    Keywords: aquatic Oligochaeta ; Psammoryctides barbatus ; growth ; cocoon production
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    Topics: Biology
    Notes: Abstract The tubificid Psammoryctides barbatus is common in the sediments of English chalk streams. The species is primarily a spring and summer breeder with the most intense period of reproduction from April to June throughout its distribution in the river. Recruitment of juveniles takes place chiefly from June to August and most of the worms attain maturity in the following spring. In culture at 15 °C worms had attained 38 mm within 90 days of hatching and showed early signs of maturity. Growth rates and rates of cocoon production in culture are presented.
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  • 21
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    Hydrobiologia 116-117 (1984), S. 456-462 
    ISSN: 1573-5117
    Keywords: seaweed ; kelp ; light ; growth ; biomass production
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  • 22
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    Hydrobiologia 116-117 (1984), S. 471-474 
    ISSN: 1573-5117
    Keywords: seaweed ; Macrocystis ; Phaeophyta ; growth ; nutrients ; composition ; morphology ; mariculture
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  • 23
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    Hydrobiologia 116-117 (1984), S. 547-550 
    ISSN: 1573-5117
    Keywords: seaweed ; Sargassum ; alginate ; growth ; seasonality ; fertility ; yield
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  • 24
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    Hydrobiologia 119 (1984), S. 65-72 
    ISSN: 1573-5117
    Keywords: life-history ; production ; growth ; Chironomus riparius ; Glyptotendipes paripes ; Chironomidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract C. riparius and G. paripes exhibited univoltine life-cycles in Stephenson Pond; pupation, emergence and oviposition occurred mainly during May, and both species overwintered as mature fourth instar larvae. The marjority of larval growth for both species took place during the fourth instar stage (August–October), and growth and production were very low during late May to mid July when only young instars were present. Low production occurred during an interval when sestonic chlorophyll a concentration was very low, and the high production period corresponded to the Aphanizomenon bloom (August) and the autumn diatom pulse. None of the growth and production parameters investigated were correlated with temperature at the mud-water interface. Tube structure and behavior of the larvae indicate that G. paripes larvae are filter-feeders, whereas, C. riparius larvae are deposit-feeders.
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  • 25
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    Hydrobiologia 118 (1984), S. 127-133 
    ISSN: 1573-5117
    Keywords: meiofauna ; Harpacticoida ; eutrophication ; stability ; colonisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The harpacticoid fauna of a sandy sediment in the Sluice Dock of Ostend, Belgium, was dominated by a single species, Canuella perplexa, that attained an average annual density of over 400 ind. 10 cm−2 in 1976 and 1977, whereas other species had a total mean density of less than 10 ind. 10 cm−2. In the summer of 1979 a dystrophic crisis with abundant growth of Ulva occurred and in March 1980 the lagoon was drained. After refilling of the lagoon, the sediment was immediately colonized by good swimming harpacticoids, that attained densities of 200 ind. 10 cm−2. Three months after refilling Canuella perplexa reappeared and the system returned to its original state within one month.
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  • 26
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    Hydrobiologia 110 (1984), S. 99-108 
    ISSN: 1573-5117
    Keywords: Sudan ; water hyacinth ; nutrients ; P, N, Fe ; growth ; White Nile
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    Topics: Biology
    Notes: Abstract The possibility that the stunted growth of the water hyacinth in Bahr el Ghazal river in Sudan is influenced by nutrient elements is considered. Greenhouse experiments were carried out to determine the effects of deficiency and mineral nutrient additions on the growth of this plant. The water hyacinth was found to grow at a wide range of nutrient levels. Maximum growth was recorded at 21 mg l−1 N, 62 mg l−1 P, and 0.60 mg l−1 Fe.
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    Mathematical methods of operations research 28 (1984), S. 193-260 
    ISSN: 1432-5217
    Keywords: Analytic behaviour of strategies ; continuous strategies ; ES strategies ; MES strategies ; machine idleness ; monotonicity behaviour ; optimal strategies ; preselectivity ; regular measure of performance ; scheduling problems ; stability ; stochastic dynamic optimization ; stochastically ordered distributions ; stochastic scheduling
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    Topics: Mathematics , Economics
    Notes: Abstract The paper contains an introduction to recent developments in the theory of non-preemptive stochastic scheduling problems. The topics covered are: arbitrary joint distributions of activity durations, arbitrary regular measures of performance and arbitrary precedence and resource constraints. The possible instability of the problem is demonstrated and hints are given on stable classes of strategies available, including the combinatorial vs. analytical characterization of such classes. Given this background, the main emphasis of the paper is on the monotonicity behaviour of the model and on the existence of optimal strategies. Existing results are presented and generalized, in particular w.r.t. the cases of lower semicontinuous performance measures or joint duration distributions having a Lebesgue density.
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    Rheologica acta 22 (1983), S. 284-290 
    ISSN: 1435-1528
    Keywords: Viscometric flow ; stability
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    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract This paper examines three-dimensional disturbances of a plane steady shear flow of simple fluids with short memory. Under the assumption of nearly-viscometric flow, constitutive equations are derived and then a general form of the Reynolds-Orr energy equation is obtained. With the aid of this derived energy formula, sufficient conditions are generated for the stability of three-dimensional disturbances of the planar viscometric flow. These conditions are analysed and a comparison is made with the corresponding two-dimensional stability problem. There is a strong indication that the basic flow is less stable against three-dimensional disturbances than against two-dimensional ones.
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    Computing 31 (1983), S. 261-267 
    ISSN: 1436-5057
    Keywords: 65M10 ; Dispersive equation ; finite difference ; stability
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    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Dieser Artikel beinhaltet eine Zusammenstellung von Differenzenverfahren für die Dispersionsgleichungu 1=au xxx. Es werden Kriterien zur Herleitung von Stabilitätsbedingungen für Differenzenverfahren angegeben und auf die angegebenen Differenzenverfahren angewendet.
    Notes: Abstract In this paper a table of difference schemes for the dispersive equationu i=au xxx is presented. A collection of criterions for deriving stability conditions of difference schemes is given and applied to these difference schemes.
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    ISSN: 1573-0603
    Keywords: growth ; differentiation ; mammary epithelium ; collagen gel
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    Topics: Biology
    Notes: Summary Mammary glands are enzymatically dissociated and the resulting tissue digest enriched for epithelial cells by isopycnic banding on a density gradient of Percoll. The cells are embedded within a rat tail collagen gel matrix and fed with the appropriate medium. Growth and differentiation are superior in such a system when compared to culture on plastic, using identical media.
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    International journal of parallel programming 12 (1983), S. 193-209 
    ISSN: 1573-7640
    Keywords: Database ; characteristic frequency ; aggregated model ; decomposition ; stability ; dynamic distribution
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    Topics: Computer Science
    Notes: Abstract A time decomposition technique is suggested for large-database (DB) models. The problem of network aggregation is studied and the results used to create a meaningful decomposed model. Decomposition conditions and assumptions are discussed and illustrated by examples. A practical operating schedule is presented for the time-separated DB model. The schedule uses a sequence of decomposed models, which are to be constructed recursively. The application of the time separation technique for large-DB models is presented in the form of a closed-loop algorithm. The problem of decomposition stability with respect to variations in time constants is considered as well. Two alternative approaches to the problem are suggested. For a probabilistic approach, practical approximate formulas are obtained for subsystem time constants and recommendations are made with respect to the decomposition structure. An approximate performance analysis is done for both standard and time-decomposed models. A comparison of the results is given.
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    Journal of pharmacokinetics and pharmacodynamics 11 (1983), S. 5-30 
    ISSN: 1573-8744
    Keywords: furazlocillin acylureido penicillin ; stability ; microbiological ; high pressure liquid chromatography assays ; red cell partitioning ; plasma protein binding ; healthy humans ; posture independent ; dose dependent pharmacokinetics of disposition ; pharmacokinetics of the penicilloic acid derivative
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    Topics: Chemistry and Pharmacology
    Notes: Abstract The pharmacokinetics of the novel acylureidopenicillin furazlocillin, 6-[D-2-(3-furfurylidenamino-2-oxo-imidazolidine-1-carboxamido)-2-(4-hydroxyphenyl)-acetamido]-penicillanic acid and of its penicilloic acid derivative were investigated in five healthy male volunteers after intravenous administration of 2 and 4 g dosages. The volunteers were either in a lying or sitting position throughout the duration of the studies. The concentrations of the drug in plasma and urine were measured by two different methods in parallel: a microbiological assay and a newly developed high pressure liquid chromatography method. The latter method was also applicable for quantitation of the penicilloic acid derivative in these biological fluids. The drug's plasma protein binding (66%) and apparent red cell-plasma partition coefficient (0.055) were concentration independent. The pharmacokinetics of the drug were first order only at the lower dose level The apparent half lives of three distinguishable phases were, respectively, 4 $$(t_{1/2_1 } )$$ , 18 $$(t_{1/2_2 } )$$ , and 64 $$(t_{1/2_z } )$$ .
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    Rheologica acta 22 (1983), S. 500-504 
    ISSN: 1435-1528
    Keywords: Coal suspension ; shear dependence ; solid phase concentration ; dispersing medium ; stability
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    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract Proper design of operations encountered in preparation, transport and employment of suspensions like coal slurries and coal-oil mixtures require an accurate knowledge of their rheological behaviour. Such concentrated suspensions generally exhibit non-Newtonian behaviour (shearthinning) which is more pronounced at higher coal concentrations. The nature of the dispersing medium influences the aggregation state of the disperse phase and, consequently, affects the stability and the rheology of the systems. In the present paper coal suspensions prepared with different dispersing media and covering a wide range in solid phase concentration are studied, by using a rotational coaxial cylinders viscometer. Different models have been taken into consideration for correlating experimental data. In particular, in order to describe the dependence of viscosity on shear rate and solid phase concentration, the suitability of the model suggested by Smith and Bruce is evaluated. Accordingly, the aggregation state of the disperse phase as well as its dependence on shear rate and dispersing medium can be estimated.
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    Human ecology 11 (1983), S. 265-281 
    ISSN: 1572-9915
    Keywords: human ecology research methods ; systems analyses ; people-forest interactions ; flux ; stability ; Man and the Biosphere (MAB) program ; Kalimantan (Borneo)
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    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Ethnic Sciences
    Notes: Abstract Theoretically or practically significant research results concerning transitory as well as persistent phenomena can be obtained by human ecologists while avoiding commitment to long-term, expensive projects, rigid frameworks, traditional disciplinary goals, and unwarranted assumptions about the stability and purposiveness of units or systems. The procedures to be followed, as illustrated by research on people-forest interactions in East Kalimantan, involve a focus on significant human activities or people-environment interactions and the explanation of these by their placement within progressively wider or denser contexts. Guides for progressively contextualizing activities or interactions include a rationality principle, comparative knowledge of contexts, and the principle of pursuing the surprising.
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    Hydrobiologia 98 (1983), S. 125-133 
    ISSN: 1573-5117
    Keywords: peritrichs ; ciliates ; streams ; aufwuchs ; stability ; diversity
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    Topics: Biology
    Notes: Abstract Artificial substrates, consisting of strips of nylon cloth, were used to sample sessile, filter-feeding ciliates at eleven stream sites. These ciliates were common (61 % of samples) and frequently abundant (mean = 95 cm−2). Populations varied widely, even within stream sites, and mean abundance was not related to subjective assessments of the sites. Permanent rural streams and streams below reservoirs, which have relatively stable flow regimes, had a peritrich fauna dominated byVorticella campanula along withCarchesium polypinum andV. striata. Urban and intermittent streams, with less stable flow regimes, showed an increasing number of peritrichs with non-contractile stalks, particularlyEpistylis plicatilis. The commonness and diversity of peritrichs was positively related to aufwuchs stability.
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    Hydrobiologia 101 (1983), S. 139-143 
    ISSN: 1573-5117
    Keywords: forest water ecosystems ; perch ; growth ; forest lake ; population density ; bottom fauna ; zooplankton
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    Topics: Biology
    Notes: Abstract Growth patterns and food composition of perch, Perca fluviatilis L., was studied in two small forest lake populations in southern Finland. Size and morphometry of the lakes and physical and chemical properties of water are similar. There is a clear difference in the growth rates of perch between the two lakes. The difference in growth is highly significant in all age groups. In the first lake there is a perch population of 2 000 (1750 ind · ha−1) adult fishes. In the second lake there is a small population of pike, that keeps the perch population down: 200 adult perch (530 ind · ha-1). The main food items of perch are crustacean zooplankton, Asellus aquaticus L. and Trichoptera larvae in the first lake and zooplankton, Odonata larvae, Ephemeroptera larvae and Heteroptera in the second. It is concluded that the main reason for the growth difference of studied perch populations is the different population density. There are also differences in species composition of bottom fauna of the lakes, maybe owing to the floating Sphagnum peat moss vegetation in the second lake. This can also affect the growth difference between the two populations of perch.
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    Hydrobiologia 104 (1983), S. 325-328 
    ISSN: 1573-5117
    Keywords: rotifers ; Keratella cochlearis ; growth ; size ; culture ; food algae
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    Topics: Biology
    Notes: Abstract Keratella cochlearis (Gosse) was cultured non-axenically in Carefoot medium diluted with Erken water at 5 °C, 15 °C and 20 °C with Rhodomonas minuta (Skuja) as a food alga. The rotifer reached ca. 120 ind. ml−1, having generation times of 2–7 days, a Q10-value of ca. 2, and at the lowest temperature 〉20% longer posterior spines. When co-cultured with Chlorella sp., at 0–30 mg Ca l−1 and 1.6 meq NaHCO3 l−1 in medium L 11 at 20 °C, the maximum generation time and individual numbers were 3–4 days and up to 100 ind. ml−1, respectively. Animal numbers increased in relation to nutrient multiples, up to two multiples, of the culture medium L 16. Growth and length were reduced, although the width increased above two multiples of this culture medium. The trace metal tolerance was broad and increased additions of a metal mixture (L 11) slightly increased the length of the rotifers. No major changes in the length were observed when HCO3 or Ca were varied in the culture medium (L 11), although a decrease in the length was noted in old cultures.
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    Journal of optimization theory and applications 40 (1983), S. 349-378 
    ISSN: 1573-2878
    Keywords: Convexity ; subdifferentials ; cones of directions of constancy ; equality set of constraints ; stability
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    Topics: Mathematics
    Notes: Abstract We present an algorithm which solves a convex program with faithfully convex (not necessarily differentiable) constraints. While finding a feasible starting point, the algorithm reduces the program to an equivalent program for which Slater's condition is satisfied. Included are algorithms for calculating various objects which have recently appeared in the literature. Stability of the algorithm is discussed.
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    Journal of optimization theory and applications 40 (1983), S. 77-83 
    ISSN: 1573-2878
    Keywords: Parameterized decision-making problems ; utopia point ; compromise solutions ; Hausdorff distance ; stability
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    Topics: Mathematics
    Notes: Abstract Stability is a desirable attribute of the nondominated solution in the decision-making problem with multiple noncommensurable objectives. It is assumed that the decision space is given by a system of inequalitiesG(x)≤b, b ∈ R N . In this paper, sufficient conditions are determined for a compromise solution to be stable with respect to the changes ofb.
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    Plant foods for human nutrition 33 (1983), S. 279-285 
    ISSN: 1573-9104
    Keywords: Ragi husk ; N-retention ; growth ; body composition ; feed efficiency ratio
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of including ragi husk in the diet, at the 8 per cent level, on growth and body composition of pair-fed albino rats was studied. Even on equal food intake by both control as well as the experimental animals, the incorporation of ragi husk promoted better growth, nitrogen retention and protein efficiency ratio. Protein content of the carcass and liver of rats fed diets containing ragi husk was higher than the control group. The growth response of rats fed ragi husk appeared to increase with the content of nitrogen in the husk.
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    Journal of optimization theory and applications 39 (1983), S. 187-214 
    ISSN: 1573-2878
    Keywords: Self-interest maximization ; self-interest stable solutions ; self-interest cooperative games ; self-interest noncooperative games ; monotonic games ; decomposition theory ; reframing game payoffs ; full cooperation ; targeted solutions ; Pareto optimality ; collective group interest ; stability ; structural departure ; incentives for adopting a new game ; habitual domain
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    Notes: Abstract Human beings have a prevailing drive to achieve their self-interest goals or equilibrium states, which may subsume their social interests. An ideal working environment or cooperative game situation would be one in which each participant or player maximizes his/her own interest while maximizing his/her contribution to the collective group interest. This paper addresses the feasibility, methods, and bounds for reframing a generaln-person game into an ideal game in which full cooperation or a targeted solution can be induced and maintained by the players' self-interest maximization. Criteria for good reframing are introduced. Monotonic games, self-interest cooperative and noncooperative games, and a decomposition theory of general games are also introduced to facilitate the study. It is shown that everyn-person game can be written as the sum of a self-interest cooperative game and a self-interest noncooperative game. Everyn-person game can be reframed so that full cooperation can be achieved by the players' self-interest maximization. Everyn-person game can be reframed so that a targeted solution can be obtained and maintained through the players' self-interest maximization.
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    Nutrient cycling in agroecosystems 3 (1982), S. 25-36 
    ISSN: 1573-0867
    Keywords: iodine ; lucerne ; ryegrass ; growth ; chemical composition ; nutrient-solutions ; ammoniacal and nitrate nitrogen ; acidity ; volatilization ; fertilizers ; grazing animals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Growth of lucerne was inhibited by sodium iodide even more than that of ryegrass above a concentration equivalent to 1µg cm−3 of iodine in an applied solution. In sand-culture the extent to which the iodide depressed yield of dry matter depended on the type of nutrient-solution used to stimulate and maintain vigorous growth. In contrast, where the plants were grown in soil the depression was independent of the nutrient-solution used. This difference between solutions is a reflection of the extent to which growing plants can modify pH in the root-zone of a sandy unbuffered substrate and leads to a conclusion that acidity greatly enhances the toxic effect of the iodine. There are reasons for believing that in sunlight iodine may be lost by volatilization even from living plant-tissue. The implication of these findings is discussed in relation to using either iodized fertilizers or iodized salt-blocks in order to maintain iodine in pastoral systems at levels satisfactory for animal-health.
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    Journal of pharmacokinetics and pharmacodynamics 10 (1982), S. 335-348 
    ISSN: 1573-8744
    Keywords: pharmacokinetics ; bioavailability ; growth ; literature growth ; logistic function
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    Topics: Chemistry and Pharmacology
    Notes: Abstract The literature growth in pharmacokinetics and bioavailability between the years 1964 and 1980 is analyzed. During much of this period, the literature doubled approximately every 1.6 years. However, during the period 1978–1980, little or no growth was observed. During the period 1950–1967, the total chemical literature increased exponentially with a half-life of 8.28 years; between 1968 and 1980, the half-life was 12.4 years. Thus, the pharmacokinetic literature increased at a much more rapid pace than did the total chemical literature in general. The subject of growth is considered in a general context, particularly as influenced by psychological, sociological, political, and economic factors. It is concluded that while mathematical functions may adequately describe past literature trends, they have little if any utility in predicting future trends in specific research areas such as pharmacokinetics.
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    Euphytica 31 (1982), S. 451-459 
    ISSN: 1573-5060
    Keywords: Malus ; apple ; gamma radiation ; mutants ; compact clones ; stability ; chimaera
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Twelve selected, compact, clones of Bramley's Seedling induced by gamma radiation treatment were checked for stability. Representative trees were used as vegetative parents for large scale multiplication, and further buds were treated with gamma radiation to disrupt the structure of their meristems. The results indicate that seven of the clones are as stable as the original cultivar, and therefore probably homohistont, containing only cells with compact mutant genotype. The other five clones proved to be unstable and gave rise to a large proportion of apparently normal trees. It is hypothesized that in these clones the L1 (epidermis) consists of normal unchanged tissue, while the bulk of the plant tissue layers are of mutant cells, i.e. that they are periclinal chimaeras with the genotypes of the different cell layers coded for different growth forms.
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    ISSN: 1573-5117
    Keywords: bream ; growth ; condition ; fecundity ; zooplankton ; chironomids
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    Topics: Biology
    Notes: Abstract The bream (Abramis brama L.) population of Tjeukemeer was studied for three successive years. The growth, condition, gonad development, diet and feeding conditions of the fish are described. Food competition for two years with the then abundant young planktivorous smelt (Osmerus eperlanus) and perch (Perca fluviatilis) resulted in a decreased growth rate, condition and gonad development of the larger bream. The biomass of chironomids was too small in relation to that of the zooplankton to be important for the bream population, although they were eaten more efficiently.
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    Colloid & polymer science 260 (1982), S. 895-910 
    ISSN: 1435-1536
    Keywords: networks ; thermo-elasticity ; van der Waals equation of state ; stability
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    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Molecular networks may be considered as elastic fluids the conformational abilities of which are adequately characterized with the aid of the model of a van der Waals conformational gas with weak interactions. The internal properties are submitted to the conditions of internal equilibrium, thus, having their changes uniquely related to the global transformations of the network upon deformation. These global properties are at least determining the limits of stability which are expressed in the van der Waals approach by formulating of a reduced equation of state of real networks. It will be discussed on hand of thermo-elastic measurements and its quantitative description what is in need for a full and self-containing phenomenological description of molecular networks.
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    Rheologica acta 21 (1982), S. 593-597 
    ISSN: 1435-1528
    Keywords: Shear deformation ; stability ; heterogeneous drop ; liquid membrane
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    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract The stability behaviour of heterogeneous drops indicates that, for liquid-liquid dispersions, we may have to modify the stability criterion to incorporate either the rheological characteristics of the dispersion or its cohesion or both.
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    Euphytica 31 (1982), S. 837-845 
    ISSN: 1573-5060
    Keywords: Evolutionarily persistent strategies ; evolutionarily stable strategies ; expansive energy ; game theory ; gene-for-gene game ; gene-for-gene relationship ; group selection ; pathosystem fitness ; persistence ; plant pathosystems ; resilience ; stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Using gene-for-gene relationships as a basis for comparison, I show that Robinson's (1979, 1980) concept of an evolutionarily stable strategy, or ESS for short, is very different from the original definition of Maynard Smith & Price (1973) and, in fact, contradicts it in a number of important respects. The notion of an evolutionarily persistent strategy, or EPS for short, is introduced to clarify these differences and to reduce the potential for confusion in the future. The EPS concept is developed in terms of Holling's (1973) concept of resilience and Van Valen's (1976) notion of expansive energy. The combination of an ESS (sensu Maynard Smith & Price, 1973) and an EPS is offered as an alternative to Robinson's (1979, 1980) ESS concept. Robinson's recommendations for a holistic approach to plant pathosystem management are supported.
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    Hydrobiologia 97 (1982), S. 75-80 
    ISSN: 1573-5117
    Keywords: growth ; Sacramento blackfish ; Orthodon ; Cyprinidae
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    Topics: Biology
    Notes: Abstract Growth rates of juvenile (1–8 g) Sacramento blackfish, an omnivorous California cyprinid which grows to 〉1.5 kg, were measured at three temperature ranges in laboratory aquaria where several diets were offeredad lib. and at four stocking densities in small ponds where natural food was available. Growth rates generally increased with elevations in environmental temperature. Growth in aquaria was possible with strictly plant-based diets, but was faster with pelleted diets higher in protein, lipids, and total calories. Growth rates in ponds increased with decreased stocking densities and approximated or exceeded those measured in laboratory aquaria for blackfish fed pelleted diets. The data also support the importance of energy-rich food organisms (e.g., zooplankton) in the diet of young-of-the-year blackfish in Clear Lake, California.
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    Hydrobiologia 94 (1982), S. 201-212 
    ISSN: 1573-5117
    Keywords: Gammaridae ; distribution ; survival ; growth ; salinity ; temperature
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    Topics: Biology
    Notes: Abstract Field collections from an inland saline lake indicated that a rapid increase in numbers of a population of Gammarus tigrinus was positively correlated with high summer temperatures and salinities. The laboratory experiments on growth are an attempt to determine whether high summer temperatures or optimum salinity were primarily responsible for the rapid increase in numbers. Furthermore, G. tigrinus was not found in either of two adjacent lakes; one non-saline, the other at a higher salinity. The laboratory experiments on survival are an attempt to determine whether the restricted distribution of G. tigrinus was related to salinity. The implications of the field and laboratory studies are discussed and compared with other data from Europe and North America.
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    Hydrobiologia 93 (1982), S. 189-194 
    ISSN: 1573-5117
    Keywords: Mysidacea ; aquatic toxicology ; toxicology ; Mysidopsis bahia ; silver ; endosulfan ; growth ; reproduction
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    Topics: Biology
    Notes: Abstract The chronic toxicity of silver and endosulfan to the opossum shrimpMysidopsis bahia was determined using continuous-flow bioassays. The 28-day bioassays measured survival, fecundity, and growth (length and weight measurements). Maximum acceptable toxicant concentrations (MATC) were estimated from measured toxicant concentrations. MATC values were similar using either brood size or growth as a criterion for sublethal effects. As an alternative to the determination of fecundity impairment, measurement of growth reduction in response to exposure to toxicants may provide a useful tool in the assessment of chronic toxicity inMysidopsis life-cycle bioassays.
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    Entomologia experimentalis et applicata 29 (1981), S. 109-116 
    ISSN: 1570-7458
    Keywords: Heteronychus arator ; Scarabaeidae ; larvae ; consumption ; utilization ; growth ; feeding ; roots ; Paspalum dilatatum ; Lolium perenne ; Trifolium repens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Futteraufnahme, die Futterverwertung und das Wachstum von Drittstadiumlarven von H. arator beim Fressen von Wurzeln von Paspalum dilatatum, Raygras (Lolium perenne) und Weissklee (Trifolium repens) wurden gravimetrisch gemessen. Der durchschnittliche Futterverzehrindex auf Gräsern war 0.65 mg/mg Larve/Woche verglichen mit 0.18 auf Weissklee. Die relative Wachstumsrate auf Paspalum und Raygras was 0.158 und 0.124 mg/mg Larve/Woche verglichen mit 0.043 auf Weissklee, was den geringen Verzehr an Weisskleewurzel widerspiegelt. Die Verwertung der gefressenen Wurzel war 22%, 18% und 24% für Paspalum, Ryagras und Weissklee. Das Fehlen gesicherter Unterschiede in der Futterverwertung der drei Pflanzenarten deutet darauf hin, dass die geringe Wachstumsrate auf Weissklee bloss durch geringe Futteraufnahme verursacht ist. Es wurde gezeigt, dass in Weisskleewurzel Frasinhibitoren für H. arator vorhanden sind. Die erhaltenen Schätzungen für Futteraufnahme durch Scarabaeiden sind die besten Daten für wurzelfressende Arten und liefern eine Basis, um den Einfluss der Weidepflanzen auf H. arator Populationen zu verstehen.
    Notes: Abstract The consumotion, utilization and growth of third-instar larvae of black beetle, Heteronychus arator (F.) feeding on roots of ryegrass (Lolium perenne), paspalum (Paspalum dilatatum) and white clover (Trifolium repens) were studied. Consumption was greater on the grasses than on white clover when assessed by gravimetric methods. Larvae had a higher growth rate on the grasses. Utilization of the roots of the three species was similar indicating that poor growth on white clover is the result of low consumption probably induced by the presence of feeding deterrents in the roots.
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    Potato research 24 (1981), S. 183-186 
    ISSN: 1871-4528
    Keywords: growth ; yield ; fertilizer mixes ; solubilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The growth of potato plants and yield of tubers were poor in plots fertilized with rock phosphate alone but the addition of pyrites so improved its efficacy that it outyielded superphosphate in one season. A mixture of rock phosphate and superphosphate, in equal proportions on a P basis, was found to be 85–93% as effective as suerphosphate in increasing tuber yield.
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    Plant foods for human nutrition 31 (1981), S. 97-108 
    ISSN: 1573-9104
    Keywords: children ; growth ; high protein rice ; nitrogen retention ; rice-based diet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of high protein milled rices (IR480-5-9 and IR2153-338-3, 10% protein) on the nitrogen retention and growth of preschool Indian children was assessed in two feeding trials in a residential home. The children were offered, ad libitum, a rice-based diet in four meals daily without vitamin and mineral supplement. The children in the experimental group were given the high protein rice; those in the control group were given a local rice (7% protein). The groups had similar percent apparent digestibility and retention of dietary nitrogen. Statistically significant differences in increase in height and weight between the two groups were not consistently observed at the end of 4.5 to 5 months or 1 year. Possible factors contributing to these results are discussed.
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  • 55
    ISSN: 1573-5117
    Keywords: catfish ; feeding rates ; growth ; body composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Food intake, growth, conversion efficiency and body composition of the non-air breathing catfish Mystus vittatus (Bloch) were studied in relation to different feeding levels. Fish weighing 817.9 ± 104.00 mg was found to consume a maximum of 156.0 mg live Tubifex worm/g day-1. Geometrically derived feeding rates of 6.75, 23.00 and 26.00 mg dry food/g live fish day-1 represent the maintenance, optimum and maximum levels respectively. The SDA increased from 6.75 mg/g day-1 at maintenance to 13.50 mg/g day-1 at maximum feeding rate. Starvation brougt about increase in body water content, while there was concomitant decrease in fat and crude protein.
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    Hydrobiologia 79 (1981), S. 239-244 
    ISSN: 1573-5117
    Keywords: aquatic pressure ; depth distribution ; growth ; Myriophyllum ; Watermilfoil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract These experimental studies have shown that this plant will grow successfully at pressures encountered in water at depths as great as 17 m. When there were suitable levels of light, temperature, nutrients and aeration, the plants grown under constant hydrostatic pressure for three weeks showed variations in the measured amounts of new growth but no measure could be associated with the constant increased hydrostatic pressure. Sudden changes in pressure are thought to play a significant role in aquatic plant growth under experimental conditions.
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  • 57
    ISSN: 1573-5117
    Keywords: Macrobrachium ; eyestalk ablation ; growth ; Conversion of food
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    Topics: Biology
    Notes: Abstract Bilateral eyestalk ablation in the freshwater prawn Macrobrachium lanchesteri results in high mortality, while unilateral eyestalk ablated prawns exhibited a high survival rate. There was marked increase in the growth of bilateral eyestalk-ablated prawns (47.70 mg/prawn) as compared to those that were unilaterally ablated (19.19 mg/prawn).
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  • 58
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    Hydrobiologia 79 (1981), S. 15-20 
    ISSN: 1573-5117
    Keywords: mineral nutrition ; growth
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    Topics: Biology
    Notes: Abstract The effect of composition of the medium and pH on the growth of Pediastrum duplex Meyen and Dictyosphaerium pulchellum Wood was studied. Both species showed preference to alkaline conditions. The ammonium nitrate grown colonies of D. pulchellum lacked mucilage and showed a more compact form, resembling D. pulchellum var. minitum Deflandre. From this it appears that D. pulchellum var. minitum is a nutritional variant of the species and not a stable variety.
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    Journal of statistical physics 25 (1981), S. 143-152 
    ISSN: 1572-9613
    Keywords: Ising model ; field theory model ; stability ; pressure ; ultraviolet divergence ; infrared divergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A field theory model onR 2 in which the basic fields are Ising spins instead of Gaussian spins is examined. Using statistical mechanics techniques we discuss the ultraviolet and the infrared problems. In particular we discuss a technique yielding the asymptotic expansion in λ of the ground state energy, as λ→0, without using the cluster expansion.
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    Human ecology 9 (1981), S. 47-78 
    ISSN: 1572-9915
    Keywords: variation ; management ; stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Ethnic Sciences
    Notes: Abstract Five concurrent systems of agricultural resource management in the Viru Valley in Peru's arid northern coastal plain are discussed as adjustments to microenvironmental variations in soil humidity. Widespread dependence on canal irrigation in an environment characterized by uncertainty in the availability of river water affects the agrarian population in several ways. The upper socioeconomic class has adapted to uncertainty by implementing a deviation-counteracting mechanism (tubular wells) that provides water on demand, giving them flexibility in choice of agricultural activities. Another class of farmers is unable to introduce this mechanism, however, and consequently must depend on a repertoire of inflexible decisions to cope with uncertainty. Each group exploits different opportunity costs to increase economic gain. One pattern provides for expansion, whereas the other at best establishes stability and maintenance. Noncanal techniques permit expansion of cultivation in conditions where canal irrigation is not feasible, thereby improving the overall level of effectiveness of resource use. Alternative techniques do not involve regulatory mechanisms nor do they require complex, interlocking social, economic, and political components. Their presence and persistence in the agricultural system provide variation that may ultimately be amplified as the need to intensify resource exploitation increases in the future.
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    Plant cell, tissue and organ culture 1 (1981), S. 69-75 
    ISSN: 1573-5044
    Keywords: colchicine ; callus tissue ; adenylates ; growth ; O2 uptake ; Daucus carota
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Colchicine effects on growth, oxygen uptake, and adenosine phosphates level of carrot (Daucus carota L.) callus tissue were determined over a period of 18 days after subculture. Colchicine at 10−3 and 10−4 M inhibited the increase in oxygen consumption which was observed with the initiation of callus tissue. Initially the same levels of colchicine stimulated AMP and ADP levels above those of the control, but later the levels returned to those of the control. Colchicine at 10−4 and 10−6 M reduced ATP levels; however, at 10−3 M there was no effect. Growth was not severely affected by the same concentrations during the same treatment period. Oxygen consumption and nucleotide metabolism were more sensitive to colchicine than was growth. Energy charge was calculated to be 0.7–0.8 in both treated and control tissue during 3–15 days in culture.
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  • 62
    ISSN: 1573-5060
    Keywords: Vicia faba ; fieldbean ; genetic variation ; stomatal characteristics ; water use ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Five genotypes of Vicia faba L. with contrasting frequencies were grown in a controlled environment in soil moisture regimes of 100%, 78% and 61% of field capacity. Growth, water use and leaf conductance characteristics were measured. Stomata were more frequent on abaxial than adaxial surfaces, the abaxial/adaxial ratio ranging from 1.12 to 1.34. There were significant (P〈0.001) correlations between calculated stomatal conductance, based on measurements of stomatal frequency and length, and leaf conductance measured with a diffusion porometer, in the two higher soil moisture treatments. In the 100% regime only, abaxial stomata opened wider than adaxial. Ranking of the genotypes for leaf conductance and plant transpiration was similar in all three regimes with large leaved types having the lowest conductance and greatest water use efficiency. Growing plants with reduced soil moisture availability improved water use efficiency, the ranking for which was also similar in all treatments. Relative growth rate and net assimilation rate were greatest with full watering, less in the 78% and least in the 61% regime. Leaf area ratio was less affected by available soil moisture and only in some genotypes.
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    Photosynthesis research 1 (1981), S. 217-231 
    ISSN: 1573-5079
    Keywords: growth ; maintenance ; Phaseolus vulgaris L. ; reserve materials ; respiration ; structural dry matter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The patterns of the CO2 exchange of single vegetative bean plants were monitored during steady state exchange and after lowering the irradiance, the CO2 concentration, or the temperature. The measured patterns were used to calculate the dynamics of the rate of synthesis of structural dry matter and of the amount of the reserve materials during the experiments. The rate of synthesis of structural dry matter was assumed to be proportional to growth respiration (total minus maintenance). The growth conversion efficiency was assumed to be independent of the treatments. The maintenance respiration coefficient was taken to be dependent only on the temperature. Change in the amounts of reserve materials was calculated as a difference between the net CO2 input and the amount converted into new structural dry matter. During the first day of a low CO2 uptake a substantial depletion of reserve materials took place also during light hours, since the rate of synthesis of structural dry matter lagged behind the decrease of photosynthesis. On the second day the rate of synthesis was adapted to the low CO2 input and there occurred little change in the amount of reserve materials. There was a rapid increase in the amount of reserve materials after the irradiance was increased again or after temperature was lowered. A saturating dependence of the specific growth rate on the content of reserve materials was found to exist irrespective of the mode of changing the content of reserve materials. A hysteresis-like retardation of the specific growth rate took place after the reserve had already been exhausted for some time. During retardation a replenishment of reserve materials took place. It is suggested that adaptation processes tend to keep the content of reserve materials within a certain (probably optimal) range.
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  • 64
    ISSN: 1573-5117
    Keywords: Turbellaria ; Dugesia ; cell types ; growth ; degrowth ; regneration ; maceration-technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A method of tissue maceration (dissociation) of planarian tissues into single cells was used to characterize the basic cell types in the planarians Dugesia mediterranea and Dugesia tigrina, and to determine the total cell number and distribution of cell types during growth, degrowth and regeneration. Using this method, 13 basic cell types have been determined for both species. The total number of cells increases with body length and volume whereas the distribution of cell types is only slightly affected. Growth and degrowth occur mainly through changes in total cell number leaving cell distribution only moderately affected. During regeneration, an increase in neoblast density in the blastema followed later on by increases in nerve cells are the more significant changes detected. These results are discussed in relation to mechanisms of cell renewal, blastema formation and maintenance of tissue polarity.
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    Journal of optimization theory and applications 34 (1981), S. 279-310 
    ISSN: 1573-2878
    Keywords: Decentralized control ; overlapping decompositions ; suboptimality ; stability ; interconnected power systems
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    Topics: Mathematics
    Notes: Abstract A decentralized control scheme is proposed for linear systems composed of overlapping subsystems. By expanding the state space of the system, a higher-dimensional space is formed where the subsystems appear as disjoint. In the expanded space, standard optimization techniques can be used to formulate a suboptimal decentralized control law for the overall system. A suitable contraction of the obtained control law, which is compatible with the information constraints imposed by the overlapping subsystems, can be implemented in the original system. The application of the proposed decentralized control scheme is illustrated using a 19th order model for load-frequency control of a two-area interconnected power system.
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    Journal of optimization theory and applications 35 (1981), S. 23-30 
    ISSN: 1573-2878
    Keywords: Contour of complete nonuniqueness ; trusses ; stability ; structural optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract This paper develops the concept of a contour of complete nonuniqueness and shows its application to the optimal design (optimal layout) of simple trusses transmitting a concentrated force to a presscribed, arbitrary foundation contour. As an example, a symmetric two-bar truss with compressed bars is considered, and the constraints refer to various kinds of elastic instability of the system.
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    Journal of optimization theory and applications 35 (1981), S. 367-401 
    ISSN: 1573-2878
    Keywords: Multiple-criteria decision making ; vector-valued duality ; saddle-point duality ; Kuhn-Tucker conditions ; Pareto optimality ; stability ; efficient points
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract In this paper, we develop a duality theory for nonlinear multiple-criteria optimization problems. The theory associates to efficient points a matrix, rather than a vector, of dual variables. We introduce a saddle-point dual problem, study stability concepts and Kuhn-Tucker conditions, and provide an economic interpretation of the dual matrix. The results are compared to the classical approach of deriving duality, by applying nonlinear programming duality theory to a problem obtained by conveniently weighting the criteria. Possible directions for future research are discussed.
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    Computing 24 (1980), S. 341-347 
    ISSN: 1436-5057
    Keywords: Numerical analysis ; Volterra integral equations of the second kind ; stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Ziel dieser Arbeit ist es, die Stabilitätseigenschaften einer Klasse Volterrascher Integralgleichungen zweiter Art zu untersuchen. Unsere Behandlung ist der üblichen Stabilitätsanalyse ähnlich, in der die Kernfunktionen zu einer im voraus beschränkten Klasse von Testfunktionen gehören. Wir haben die Klasse der “endlich zerlegbaren” Kerne betrachtet. Stabilitätsbedingungen werden abgeleitet und verglichen mit den Bedingungen für die einfache Testgleichung. Es zeigt sich, daß die neuen Kriteria einschränkender sind als die konventionellen Bedingungen. Der praktische Wert wird getestet durch numerische Experimente mit der Trapezregel.
    Notes: Abstract The purpose of this paper is to analyse the stability properties of a class of multistep methods for second kind Volterra integral equations. Our approach follows the usual analysis in which the kernel function is a priori restricted to a special class of test functions. We consider the class of finitely decomposable kernels. Stability conditions will be derived and compared with those obtained with the simple test equation. It turns out that the new criteria are more severe than the conventional conditions. The practical value is tested by numerical experiments with the trapezoidal rule.
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    Archive for rational mechanics and analysis 72 (1980), S. 203-218 
    ISSN: 1432-0673
    Keywords: simple fluid ; viscoelastic ; fading memory ; stability ; Liapunov function ; dynamical system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract The nonlinear equations of motion for an incompressible simple fluid, occupying a fixed bounded container, are formulated on the basis of the “finitelinear” viscoelasticity theory for materials with fading memory; this formal boundary-initial value problem is then viewed as a nonlinear abstract evolution equation on a certain Hilbert space. It is shown that a linearized version of this evolution equation is associated with a linear dynamical system on this Hilbert space, and several results for stability and asymptotic behavior for this linearized problem are proved through the use of Liapunov stability methods. On the assumption that the original nonlinear evolution equation also is associated with some dynamical system on the same space, it is shown that the rest condition of the fluid is stable and all motions are bounded. The Liapunov function employed for this purpose can be interpreted as a mechanical energy function for the fluid.
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    Nutrient cycling in agroecosystems 1 (1980), S. 177-190 
    ISSN: 1573-0867
    Keywords: winter wheat ; nitrogen uptake ; autumn dressing ; split-dressing ; growth ; grain yield ; protein content ; harvest-index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field experiment with the winter wheat cultivar Donata was carried out on a fine-textured river clay soil in 1978. The rates of nitrogen dressing ranged from 0 to 160 kg N per ha and were split over from one up to three application times: autumn, early spring and late spring. Total above-ground dry matter and grain dry-weight yields ranged from 9.1 to 13.7 tons per ha and from 4.17 to 6.35 tons per ha, respectively. Late top-dressings increased the harvest-index, whereas an autumn dressing had the opposite effect. Number of culms per m2, grain weight (mg) and grain number per m2 increased from 350 to 430, from 35.5 to 36.8 and from 11 680 to 16 980, respectively, as the nitrogen dosage was raised from 0 to 160 kg N per ha. The linear rate of grain growth ranged from 111 to 172 kg dry matter per ha per day with nitrogen doses from 0 to 160 kg N per ha. Differences in rate of grain growth per unit area were mainly related to number of grains per m2. The association between grain number and grain yield was reflected by a correlation coefficient of 0.97 (n = 32). A higher level of nitrogen dressing enhanced the leaf area index and leaf area duration. However, we could not derive an effect of nitrogen on the duration of grain growth. Total nitrogen yield ranged from 71 to 166 kg N per ha and grain nitrogen yield from 54 to 122 kg N per ha with nitrogen dosages of 0 and 160 kg N per ha, respectively. The nitrogen concentration of the grains varied between 1.3 and 2.0 N. An autumn dressing of 40 kg N per ha generally showed only minor effects on yield and yield components. Top dressings during spring resulted in a higher recovery and efficiency of the applied nitrogen. Therefore, it may be concluded from this experiment and literature that on fertile soils an autumn dressing of nitrogen will not be economical, but split-dressings in spring are very beneficial. In particular, a late nitrogen application during the boot stage increased grain number, harvest-index and grain yield as well as protein concentration of the grain.
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  • 71
    ISSN: 1572-9613
    Keywords: Correlation inequalities ; classical and quantum continuous systems ; positive type potentials ; stability ; thermodynamic limit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study quantum mechanical systems of particles with Bose or Fermi statistics interacting via two-body potentials of positive type in thermal equilibrium. We rewrite partition functions, reduced density matrices (RDMs), and correlation functions in terms of Wiener and Gaussian functional integrals (sine-Gordon transformation). This permits us, e.g., to apply correlation inequalities. Our main results include an analysis of stability versus instability in the grand canonical ensemble and, for charge-conjugation-invariant systems, upper and lower bounds on RDMs, the existence of the thermodynamic limit of pressure, RDMs and correlation functions, an inequality comparing correlations with Fermi statistics to ones with Bose statistics, and inequalities which are important in the study of Bose-Einstein condensation and of superconductivity.
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    Hydrobiologia 72 (1980), S. 125-129 
    ISSN: 1573-5117
    Keywords: Phytoplankton ; respiration ; photosynthesis ; growth ; feedback mechanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the eutrophic Bautzen reservoir (German Democratic Republic) the compensation light intensities (photosynthesis = respiration of the phytoplankton) have been found to be extremely low if no free carbon dioxide is available. This result is interpreted as a minimization of the cell respiration under CO2-limitation of the photosynthesis.
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  • 73
    ISSN: 1573-5117
    Keywords: Salamandra ; Urodela ; metamorphosis ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Salamandra salamandra larvae originating from a single batch (layed by one female) were raised at different temperatures and on ion-rich or distilled water. Temperature, but not the presence or absence of ions affected growth. Larvae originating from one batch or from several batches born on the same day, were kept without food for long periods of several months in order to observe cannibalistic predation under such conditions. This phenomenon is known in natural populations of salamanders inhabitating either rain pools in rocks or permanent springs poor in aquatic life. It was found that cannibalism increased under experimental conditions proportionally to the increase in size between the larvae.
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  • 74
    ISSN: 1572-9613
    Keywords: Harmonic oscillator ; stochastic frequency ; stochastic differential equation ; stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Using a simple matrix method, we have obtained exact second-order equilibrium moments for a linearly damped harmonic oscillator with a fluctuating frequency ω(t) and driven by a fluctuating forcef(t). We have assumed each of the fluctuating quantities to be delta-correlated. We demonstrate that the final answers are identical whetherf(t) and ω(t) are statistically independent or delta-correlated. We have also established the region of parameter space in which the oscillator is energetically stable. The results are shown to be completely determined by the coefficients of the first and second cumulants of the fluctuations.
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    Hydrobiologia 70 (1980), S. 37-38 
    ISSN: 1573-5117
    Keywords: blue-green algae ; Alloxan ; growth ; pigments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Effect of Alloxan was studied on a nitrogen-fixing blue-green alga: Westiellopsis prolifica in pure cultures. Concentrations of Alloxan, 10 μg to 50 μg/ml stimulate the growth of the alga and increase the chlorophyll, carotin and phycocyanin content of the cultures.
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    Hydrobiologia 71 (1980), S. 87-93 
    ISSN: 1573-5117
    Keywords: Chara ; rubidium ; caesium ; requirement of nutrients ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Le rubidium et le césium introduits à l'état de chlorure dans le milieu de culture ont à faible dose un effet stimulant sur la croissance de Chara fragilis et de Chara vulgaris. La résistance de ces végétaux à l'action toxique des deux ions est accrue par l'addition de potassium au milieu. Les analyses chimiques confirment que le rubidium et le césium sont antagonistes vis-à-vis du potassium et du sodium alors qu'ils ne modifient pas de manière significative le taux de calcium.
    Notes: Abstract Chara fragilis and Chara vulgaris were cultivated in a natural medium containing rubidium and caesium as chloride. The growth of Characeae was increased after culture in the solutions containing Rb and Cs in small amount. The resistance to the toxic effects of these two ions is enhanced if potassium chloride is added to the medium. Quantitative analyses indicate that Rb and Cs decrease the rate of Na and K but have no significative influence on the rate of Ca.
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    Hydrobiologia 72 (1980), S. 21-30 
    ISSN: 1573-5117
    Keywords: Sewage ponds ; BOD-removal ; stability ; Daphnia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By arranging sewage ponds in series, some feedback relationships within the food web are disconnected, but stability may increase. This particularly applies to a persistent ‘clearwater-state’ in the last cell caused by mass growths of Daphnia or other zooplankton in the absence of fish. Microbial pollution in this case is reduced to a level which may permit nearly unrestricted irrigation. The oxygen balance of lagoons is, apart from the diurnal cycle, subject to substantial temporal variations. This also applies to continuous-flow laboratory models with a constant (BOD-load, temperature) or a constant-cycle (light) chemical and physical environment. An example is given illustrating a high adjustment stability of a lagoon in consequence of a catastrophic perturbation. The strong tendency of lagoons towards an oligomictic behaviour is promoted by thermal stratification and by a vertical gradient in the metabolic activity (oxidation/reduction potential). The hydrodynamic conditions oscillate between plug flow in periods of convective overturn and short-circuiting if thermal stratification has developed. Nevertheless, the average performance (BOD removal) for a particular season could be calculated with a reasonable accuracy. As a basis for this calculation, nomographs were developed from which the rate coefficient K1 of BOD removal for a given combination of residence time and BOD load can be read.
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    Journal of optimization theory and applications 30 (1980), S. 229-253 
    ISSN: 1573-2878
    Keywords: Point-to-set maps ; domination structures ; parameterized decision-making problems ; solution maps ; stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Decision-making problems with multiple noncommensurable objectives are specified by two factors, i.e., the set of all feasible solutions and the domination structure. The solutions are characterized as nondominated points. Hence, in these problems, there may exist two parameter vectors, according to which the above two factors change. The stability of the solution set for perturbations of these parameters is investigated in this paper. The analysis is guided by using the concept of continuity of the solution map defined on the two parameter spaces.
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    Journal of optimization theory and applications 31 (1980), S. 515-533 
    ISSN: 1573-2878
    Keywords: Optimal control ; economic systems ; stability ; existence theory ; turnpike property
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Sufficient conditions for the existence of optimal trajectories and for the global asymptotic stability of these trajectories are given for a class of nonconvex and nonautonomous systems controlled over an infinite-time horizon. The concept ofG-supported trajectory is introduced. It is shown that, under some assumptions, aG-supported trajectory is overtaking and is globally asymptotically stable. The concept of overtaking trajectory has been previously defined as a notion of optimality on an infinite-time domain. For autonomous systems, under weaker conditions, one guarantees the existence of weakly overtaking trajectories. Finally, it is shown howG-supported trajectories can be obtained, and an application to the study of a pre-predator ecosystem optimally harvested is sketched.
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    Bulletin of experimental biology and medicine 90 (1980), S. 1591-1593 
    ISSN: 1573-8221
    Keywords: electromagnetic field ; fluctuation ; growth ; carcinogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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