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  • Column liquid chromatography  (54)
  • Competition  (33)
  • ASTROPHYSICS
  • Data analysis / ~ processing
  • Industrial Chemistry
  • Inorganic Chemistry
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  • Seismology
  • Springer  (88)
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  • 1985-1989  (89)
  • 1950-1954
  • 1987  (89)
  • 1
    Electronic Resource
    Electronic Resource
    Colonization of wheat seedling (Triticum aestivum) roots by Pseudomonas fluorescens and Bacillus subtilis (1987)
    Springer
    Biology and fertility of soils 4 (1987), S. 41-46 
    Details
    ISSN: 1432-0789
    Keywords: Competition ; Migration ; Colonization potential ; Replica printing ; Triticum aestivum ; Pseudomonas fluorescens ; Bacillus subtilis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Colonization patterns of Pseudomonas fluorescens and Bacillus subtilis on roots of wheat seedlings growing on water agar were studied qualitatively by replica printing and quantitatively by the plate count method. The results indicated a stronger colonization potential for P. fluorescens (up to 107 cfu/cm root) than for B. subtilis (up to 105 cfu/cm root). Although the numbers of both species were lower when inoculated together, the observed colonization patterns on the roots were comparable to those found with single inoculations. For none of these bacteria was active migration along the root surface in any direction observed, indicating that distal positions are reached mainly by a passive displacement on the root tip and elongating cells. Ecological implications of the observed phenomena are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00280349
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  • 2
    Electronic Resource
    Electronic Resource
    Desiccation, predation, and mussel-barnacle interactions in the northern Gulf of California (1987)
    Springer
    Oecologia 74 (1987), S. 304-309 
    Details
    ISSN: 1432-1939
    Keywords: Barnacles ; Competition ; Desiccation ; Mussels ; Predation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Field experiments were conducted in order to determine the potential for desiccation and predation to mediate the effect of mussels (Brachidontes semilaevis) on barnacles (Chthamalus anisopoma) in the highly seasonal northern Gulf of California. We did this by removing both mussels and a common mussel predator (Morula ferruginosa: Gastropoda) and by spraying selected sites with sea water during summertime spring low tides. We also determined the effect of crowding on resistance to desiccation in barnacles, and the effect of barnacles on colonization by mussels. The mussel-barnacle community was not affected by keeping experimental quadrats damp during daytime low tides throughout the summer. Exposure to summertime low tides, however, did affect the survivorship of isolated, but not crowded, barnacles; and barnacle clumps enhanced the recruitment of mussels. Hence crowding in barnacles had a positive effect on both barnacle survivorship and mussel recruitment. Morula had a negative effect on mussel density, and mussels had a negative effect on barnacle density. The effect of Morula on barnacle density was positive, presumably due to its selective removal of mussels. These results suggest an indirect mutualism between barnacles and the gastropod predator, because barnacles attract settlement or enhance the survival of mussels, and the predator reduces the competitive effect of mussels on barnacles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379374
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of competition on the demography of planktonic cladocerans — Daphnia and Diaphanosoma (1987)
    Springer
    Oecologia 74 (1987), S. 468-477 
    Details
    ISSN: 1432-1939
    Keywords: Cladocera ; Competition ; Time lags ; Oscillations ; Plankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Isolated and mixed continuous cultures of Daphnia hyalina and Diaphanosoma brachyurum in lake water were maintained under laboratory conditions to elucidate demographic effects of competition. Population dynamics curves were obtained. Interspecific competition was revealed by the decrease in the average density of animals in the mixed versus isolated cultures and by the extinction of one species in the presence of the other. Within the first 50 days either Diaphanosoma (4 cases) or Daphnia (1 case) was the superior competitor, depending on the initial conditions. Further cultivation resulted in the extinction of Diaphanosoma in the mixed cultures. There were no statistically significant differences between the maximum rates of population increase (r m ) in Daphnia and Diaphanosoma at the concentration of edible algae about 2·105 μm3ml-1(0.293 and 0.286 days-1, respectively). Time lags for density-dependent parameters of the populations were evaluated by means of rank cross-correlations. Regardless of the species identity the time lags of fecundity, birth rate, and the rate of population growth were significantly higher in the superior competitor. The initial conditions of culturing affected the time lags which in their turn influenced the outcome of the interaction. Enhanced competitive ability due to the maximized time lags in Daphnia was not associated with the loss of population stability. Conversely, it brought about destabilization of Diaphanosoma populations which seemed to be the ultimate cause of its extinction observed in the end of the experiment. Time lag of the population growth rate was well predicted based on the half-sum of time lags in birth and death rates (r2=0.80, P〈0.001). Daphnia responded to competition with a sharp shortening of the time lags of fecundity, birth rate, and the population growth rate. It increased clutch size and showed inverse relationship between the fecundity time lag and average fecundity even though it was strongly suppressed by Diaphanosoma. The competitive ability was not related to the percentage of adults in the populations. In contrast to the current belief the major result of interspecific competition in the experiment was not a decrease in the rate of population growth but was a reduction in population time lags.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378946
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  • 4
    Electronic Resource
    Electronic Resource
    Experimental evidence for interactive habitat segregation between roach (Rutilus rutilus) and rudd (Scardinius erythrophthalmus) in a shallow eutrophic lake (1987)
    Springer
    Oecologia 73 (1987), S. 21-27 
    Details
    ISSN: 1432-1939
    Keywords: Competition ; Habitat segregation ; Foraging efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The competitive interactions between roach (Rutilus rutilus) and rudd (Scardinius erythrophthalmus) were investigated in two habitats, the open water and the waterlily zone. The growth rates of both species in enclosures were lower when confined together than when alone, demonstrating interspecific competition. Allopatric roach had the highest growth rate in both habitats although the open water was preferred. The diets of both species were dominated by zooplankton in both the open water and waterlily zones. In laboratory experiments, roach had significantly higher feeding rates than rudd when fed D. magna and Cyclops sp. The impact of roach on the mean sizes and densities of zooplankton in the enclosures, together with the results from the laboratory study, indicate that roach were competitively superior in the open water. Because of high mortality in the sympatric waterlily enclosure, no conclusions about interspecific competition in this habitat could be drawn. The observed habitat segregation between roach and rudd was at least partly interactive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00376972
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  • 5
    Electronic Resource
    Electronic Resource
    Experimental studies of exploitative competition in a grazing stream insect (1987)
    Springer
    Oecologia 73 (1987), S. 41-47 
    Details
    ISSN: 1432-1939
    Keywords: Algal-grazer interactions ; Competition ; Food depletion ; Food limitation ; Streams
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Field and laboratory experiments were conducted to determine whether intraspecific competition for food occurs during the larval stage of the periphyton-grazing caddisfly Glossosoma nigrior (Trichoptera: Glossosomatidae). Larvae were placed in field enclosures at densities less than, equal to, or greater than their natural densities. Most of these individuals began to pupate after ∼3 weeks, whereupon the mass of each individual was determined. Final mass declined significantly as larval densities increased, whereas neither developmental rate nor mortality/emigration rate was significantly affected by density manipulations. a supplemental experiment comparing the final mass of individuals grown at reduced densities in a laboratory stream with individuals from a natural stream bottom confirmed the results of the more extensive field experiment: reductions in density resulted in significant increases in final mass. Periphyton availability in field enclosures declined according to a negative exponential function as larval densities increased. Over the ∼25-fold range of larval densities used in these experiments, the final mass of individuals increased linearly with periphyton standing crops. This result suggests that Glossosoma larvae may compete for food even at densities below those employed in this study. Path analysis was used to explore the importance of indirect (i.e., exploitative) and direct (i.e, interference) mechanisms for the observed competitive effects. The analysis indicates that a model based solely on exploitation explains nearly as much of the variance in mass as a model incorporating both interference and exploitation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00376975
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  • 6
    Electronic Resource
    Electronic Resource
    Herbivory and intraspecific competition in a stream caddisfly population (1987)
    Springer
    Oecologia 73 (1987), S. 75-81 
    Details
    ISSN: 1432-1939
    Keywords: Herbivory ; Competition ; Periphyton ; Helicopsyche ; Stream
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Field experiments were conducted to assess the effects of different population densities of the herbivorous caddisfly Helicopsyche borealis on periphyton biomass and on its own growth rate in Big Sulphur Creek, a third-order stream in northern California, USA. Stream enclosures were used to vary grazer density from one-eighth to twice natural density (1/8X–2X) in two experiments (35 d and 60 d), which spanned the period of most rapid larval growth. Periphyton biomass and chlorophyll a were inversely related to grazer density. Grazer densities of 1/8X–1/2X moderately reduced periphyton when compared to an ungrazed control, whereas densities of 1X–2X greatly depleted periphyton. The growth rate of H. borealis larvae declined with increasing larval density. Growth rate was highest at densities of 1/8X–1/2X; larvae grew more slowly at 1X and showed no growth at 2X. Weekly supplementation of periphyton to 1/4X, 1X, and 2X densities significantly increased the final body mass of larvae at 1X and 2X (by 26% and 50%, respectively, compared to unsupplemented larvae) but did not change the body mass of larvae at 1/4X. These results suggest that periphyton is a limiting resource in Big Sulphur Creek and that H. borealis larvae compete exploitatively for that resource. Intraspecific competition may be an important, but often overlooked, feature of many herbivore populations in streams.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00376980
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  • 7
    Electronic Resource
    Electronic Resource
    A comparative study on nutrient cycling in wet heathland ecosystems (1987)
    Springer
    Oecologia 74 (1987), S. 174-184 
    Details
    ISSN: 1432-1939
    Keywords: Nutrient cycling ; Litter production ; Competition ; Relative nutrient requirement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The term relative nutrient requirement is introduced in order to measure and to compare the nutrient losses from different perennial plant populations and the amount of nutrient that they need to absorb to compensate these losses. The relative nutrient requirement (L) is defined as the amount of the growth-limiting nutrient that must be taken up to maintain or replace each unit of biomass during a given time interval (e.g., mgN g-1 biomass year-1). It is derived that in a plant community with two competing perennial plant populations, species1 will become dominant if the relative competition coefficient k 12 (sensu De Wit 1960) exceeds the ratio between the relative nutrient requirements of the two species (L 1/L 2), whereas species 2 will become dominant, if k 12 is below this critical ratio. The above-ground litter production was measured inwet heathland communities dominated by Erica tetralix or by Molinia caeruleain order to estimate N and P losses from theaboveground biomass and to calculate the relative N and P requirements of these species. Molinia lost during one year 63% and 34%, respectively, of the amount of N and P present in the above-ground biomass at the end of the growing season. These losses were in Erica 27% and 31%, respectively. The relative N requirements of the two species show the same difference: 7.5 and 2.6 mg N g-1 yr-1, respectively, in Molinia and in Erica. Also the relative P requirement of Molinia is higher as well as that of Erica (0.18 versus 0.08 mg P g-1 yr-1). The relative competition coefficient of Molinia with respect to Erica (k me ) is equal to unity under unfertilized conditions but increases with increasing nutrient supply. Under nutrient-poor conditions k me is below the critical ratio of the relative nutrient requirements of the two species (L m /L e =2.9 or 2.3), so that Erica will be the dominant species. After an increase in nutrient availability k me increases and exceeds this critical limit which results in Molinia replacing Erica. During the last 20 years this replacement of Erica-dominant communities by monocultures of Molinia has been observed in almost all wet heathlands in The Netherlands along with a strong increase in nitrogen availability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379357
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  • 8
    Electronic Resource
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    Photosynthetic kinetics determine the outcome of competition for dissolved inorganic carbon by freshwater microalgae: implications for acidified lakes (1987)
    Springer
    Oecologia 73 (1987), S. 307-311 
    Details
    ISSN: 1432-1939
    Keywords: Algae ; Photosynthesis ; Competition ; pH ; Acidification ; Dissolved inorganic carbon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Photosynthetic kinetics with respect to dissolved inorganic carbon were used to predict the outcome of competition for DIC between the green alga Selenastrum minutum and the cyanobacterium Synechococcus leopoliensis at pH 6.2, 7.5, and 10. Based on measured values of the maximum rate of photosynthesis, the half-saturation value of photosynthesis with respect to DIC (K 1 2/DIC ), and the DIC compensation point, it was predicted that S. leopoliensis would lower the steady-state DIC concentration below the DIC compensation point of S. minutum. This should result in competitive displacement of the green alga at a rate equivalent to the chemostat dilution rate. This prediction was validated by carrying out competition experiments over the range of pH. These results suggest that the low levels of DIC in air-equilibrated acidified lakes may be an important rate-limiting resource and hence affect phytoplankton community structure. Furthermore, the low levels of DIC in these systems may be below the DIC compensation point for some species, thereby precluding their growth at acid pH solely as a function of DIC limitation. The potential importance of DIC in shaping phytoplankton community structure in acidified systems is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377523
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  • 9
    Electronic Resource
    Electronic Resource
    On the use of response models in mixture experiments (1987)
    Springer
    Oecologia 72 (1987), S. 95-103 
    Details
    ISSN: 1432-1939
    Keywords: Models ; Bromass ; Competition ; Density ; Resource use
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Methods for assessing mixtures and their dynamic interaction over time are proposed, based on response functions relating biomass yield of each species to the densities of the component species. This approach allows a number of different facets of mixtures to be studied in a common framework. Two examples are given. Substitution rates between species and perceived densities for individuals in mixture are defined. These measure the impact of their environment on individuals. The relative resource total (RRT), is suggested as an index of whether species are capturing the same resource amount in mixture as in pure stand. Two indices of the comparative performance of species over time are proposed. The two examples, one with cattle and sheep and the other a plant mixture diallel with 6 genotypes illustrate the use of the methods. In the animal example the maximum yield mixture was calculated, the species perceptions of each other assessed and it is shown that mixing increased the resource capture by up to 17%. In general, the smaller species performed relatively better in mixture over the experimental period. In the plant example, individual plant size varied considerably over genotypes and this was reflected in their perceptions of each other, but not in their pure stand or mixed crop yield potential. Most genotype pairs showed antagonistic behaviour, whether measured by crop yield potential or by the index of resource capture. These conclusions are contrasted with those from an analysis of the data using substitutive methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385051
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  • 10
    Electronic Resource
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    Resource partitioning and competition for shells between intertidal hermit crabs on the outer coast of Washington (1987)
    Springer
    Oecologia 72 (1987), S. 248-258 
    Details
    ISSN: 1432-1939
    Keywords: Pagurus ; Competition ; Resource partitioning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Resource partitioning was quantified for 6 species of intertidal hermit crabs in the genus Pagurus, that occur on the outer coast of Washington. This, together with field evidence of shell shortage and with laboratory experiments to quantify the mechanism of interactions for shells, allowed estimation of the relative intensities of inter-and intraspecific competition between these species. The findings were that: (1) the magnitude of intraspecific competition was greater than any single interspecific competitive effect for all of the species; and (2) the relative proportion of intraspecific competition was greater for the middle and upper intertidal species than for the lower intertidal species. Studies at several outer coast sites supported these generalizations. Both of these findings are consistent with the hypothesis that competitive divergence has occurred in the past. The structure of the outer coast hermit crab assemblage is compared with that of the San Juan Archipelago hermit crab assemblage. Differences between the two do not seem to be the result of adaptive responses to the presence of more competing species in the former group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379275
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  • 11
    Electronic Resource
    Electronic Resource
    Competition for nutrients between Calluna vulgaris (L.) Hull and Molinia caerulea (L.) Moench (1987)
    Springer
    Oecologia 73 (1987), S. 105-107 
    Details
    ISSN: 1432-1939
    Keywords: Competition ; Nutrients ; Heathland ; Calluna vulgaris ; Molinia caerulea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A combination of a removal and fertilization experiment in the field and a replacement experiment in containers in a cold frame was carried out to investigate the role of nutrient supply in the interactions between Calluna vulgaris and Molinia caerulea. It is concluded that the growth of Calluna as well as that of Molinia increased with increasing nutrient availability. However, the increase in biomass of Molinia was much larger than that of Calluna. It is also concluded that increased nutrient availability favours the competitive vigour of Molinia in interaction with Calluna.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00376984
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  • 12
    Electronic Resource
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    Carbon dioxide assimilation in the flowerhead of Arctium (1987)
    Springer
    Oecologia 73 (1987), S. 109-115 
    Details
    ISSN: 1432-1939
    Keywords: Flowerhed photosynthesis ; Carbon balance ; Competition ; Arctium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The gas exchange of flowerheads was determined in Arctium tomentosum and A. lappa during their development. The light, temperature and CO2 responses were used to estimate flowerhead photosynthesis and the in situ contribution of carbon assimilation to the carbon requirement of the plant for supporting a flowerhead. Changes in vapour pressure deficit had no effect on flowerhead photosynthesis rates and were not included in the model. In both species assimilatory capacity correlated with total bract chlorophyll content. Light, temperature and CO2 response curves were very similar in form between species, differing only in absolute rates. During all stages of development, flowerheads always exhibited a net carbon loss, which was mainly determined by temperature. The respiration rate decreased in the light, the difference of CO2 exchange in the dark and in the light was interpreted as photosynthesis. This rate was larger in A. lappa than in A. tomentosum. 30% of the total C requirement of A. lappa flowerheads was photosynthesized by its bracts, the total contribution offlowerhead photosynthesis in A. tomentosum was only 15%. The potential competitive advantages of variation in flowerhead photosynthesis are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00376985
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  • 13
    Electronic Resource
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    Response of traplining bumble bees to competition experiments: shifts in feeding location and efficiency (1987)
    Springer
    Oecologia 71 (1987), S. 295-300 
    Details
    ISSN: 1432-1939
    Keywords: Aralia ; Bombus ; Competition ; Energy budget foraging ; Niche shift ; Trapline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In field experiments, we mapped the regular foraging routes (traplines) of marked bumble bees visiting Aralia hispida. When other bees were removed to create localized “competitive vacuums”, the marked bees shifted their feeding activity toward the removal areas. Bees foraging in these competitive vacuums probed more flowers per inflorescence than control bees. One bee's foraging was studied intensively before and after its local competitors were removed. Compared to four nestmates foraging elsewhere, the focal bee's trip times were shorter (p〈0.005) and its food collection rate was marginally higher (P=0.064) during the removal, although all the bees foraged similarly before the removal. These observations indicate that traplining bumble bees opportunistically modify their use of space in response to the activities of other bees in a highly competitive environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377298
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  • 14
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    On the analysis of competition at the level of the individual plant (1987)
    Springer
    Oecologia 71 (1987), S. 308-317 
    Details
    ISSN: 1432-1939
    Keywords: Competition ; Population density ; Emergence time ; Yield ; Annuals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The extent to which some measure of local crowding can account for the performance of individual plants is examined with reference to populations of two species of annual plant. Only a relatively small proportion of the variation in individual plant yield could be accounted for by measures of local crowding. These included the number of close neighbours, an estimate of the area available to each plant and competitive pressure. A multiple regression that took account of both emergence time and local crowding increased the proportion of variance that could be accounted for up to 50%. Computer simulations of the growth of indivudual plants in monoculture were then caried out in order to determine whether the unexplained variation resulted from fundamental flaws in the models or from unaccounted for sources of variation in the field. The results from the simulations again indicated that only a relatively low proportion of the variation in individual plant yield could be accounted for by emergence time and local density, even though these were known to be the only variables present. These findings are discussed in relation to the relative importance of one-sided and two-sided competition, and the complex cross-correlations that occur between individuals in plant populations. These two factors will make it very difficult for field workers to determine accurately what factors determine individual plant yield and in particular to predict the effects of local crowding on the performance of individual plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377300
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  • 15
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    Effects of habitat and season on competitive interactions between roach (Rutilus rutilus) and perch (Perca fluviatilis) (1987)
    Springer
    Oecologia 73 (1987), S. 170-177 
    Details
    ISSN: 1432-1939
    Keywords: Competition ; Habitat ; Season ; Temperature ; Fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The competitive interactions between two distantly related fish species, roach (Rutilus rutilus) and perch (Perca fluviatilis), were studied in enclosures in two habitats. In the open water habitat dominated by small planktonic prey perch grew more slowly and altered its diet from zooplankton to benthic macroinvertebrates when in the presence of roach. No effect, however, of perch on roach was observed. This was probably caused by the higher foraging efficiency of roach on zooplankton (laboratory experiments) and to the presence of a resource utilizable only by roach, bluegreen algae/detritus. In the littoral habitat no interspecific effects were detected even though resources were more limiting. This was probably a consequence of the higher densities of chironomids, on which perch fed more efficiently than roach, and of the presence of bluegreen algae/detritus. Roach, which consumed a larger spectrum of food types than perch, as a result was less affected by competition. The distributions of the species in the lake corresponded to what could be predicted from experiments. The degree of resource limitation varied with season and was highest in summer, while no resource limitation was observed in spring. This variation in resource limitation is probably caused by the increased metabolic demands of the fish in summer.
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    URL: http://dx.doi.org/10.1007/BF00377504
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  • 16
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    An analysis of competitive interactions between 3 hermit crab species (1987)
    Springer
    Oecologia 72 (1987), S. 233-247 
    Details
    ISSN: 1432-1939
    Keywords: Pagurus ; Competition ; Resource partioning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Competition for empty gastropod shells in a group of three sympatric hermit crabs (Pagurus hirsutiusculus, Pagurus granosimanus, and Pagurus beringanus) was studied in the San Juan Archipelago, Washington State. Estimates of the competitive effects of each species on the others' shell supplies were derived using field data on shell utilization and the results of laboratory experiments to determine rates of acquisition and exchange of shells and preferences for different shell species. Each species experienced approximately an order of magnitude more intraspecific competition than interspecific competition for empty shells. This resulted from differences in preference for shell shapes, shell size use, and habitat use between P. hirsutiusculus and P. granosimanus, and largely from differences in habitat use between P. beringanus and the other two species. Experiments involving the release and recensusing of marked empty shells were used to estimate competitive effects more directly for the interaction between P. hirsutiusculus and P. granosimanus. Results were consistent with the estimates derived from data on resource partitioning. Possible causes of the low levels of interspecific competition are discussed, and results are compared with studies of other organisms that estimated both inter- and intra-specific competition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379274
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  • 17
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    Characteristics of successful competitors: an evaluation of potential growth rate in two cold desert tussock grasses (1987)
    Springer
    Oecologia 71 (1987), S. 167-173 
    Details
    ISSN: 1432-1939
    Keywords: Agropyron ; Artemisia ; Relative growth rate ; Competition ; Tussock grass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Within the first few weeks after seedling emergence, Agropyron desertorum, a more competitive tussock grass, had a much higher mean relative growth rate (RGR) than Agropyron spicatum, a very similar, but less competitive species. However, beyond the early seedling stage, the two grasses had a remarkably similar whole-plant RGR in hydroponic culture and aboveground RGR in glasshouse soil, if root temperatures were above approximately 12°C. At soil temperatures between 5 and 12°C, A. desertorum exhibited a 66% greater aboveground RGR than A. spicatum (P〈0.05). Both species responded similarly to warming soil temperatures. In the field, however, tiller growth rates were generally similar. Neither species showed marked tiller elongation until a couple of weeks after snowmelt, by which time soil temperatures, at least to a depth of 10 cm, were above 12°C for a significant portion of the day. Aboveground biomass accumulation over a three-year period indicated that both grasses had similar potential growth rates whereas Artemisia tridentata ssp. vaseyana, a common neighbor planted in the same plots, had a much greater potential growth rate. The greater competitive ability of adult A. desertorum, as compared to A. spicatum, cannot be attributed to appreciable differences in potential growth rates.
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    URL: http://dx.doi.org/10.1007/BF00377281
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  • 18
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    Intraspecific interference among larvae in a semivoltine dragonfly population (1987)
    Springer
    Oecologia 71 (1987), S. 447-456 
    Details
    ISSN: 1432-1939
    Keywords: Benthos ; Cannibalism ; Competition ; Field experiment ; Odonata ; Predation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This study focuses on ways that the size distribution of individuals influences the types and intensities of competitive interactions within a population of aquatic arthropod predators. Three field experiments and one laboratory experiment were designed to test for feeding interference, interference mortality, and dispersal effects within and between larval size classes of the primarily semivoltine dragonfly Tetragoneuria cynosura in Bays Mountain Lake. One field experiment documented the temporal pattern of colonization of large-mesh cylinders by the small, first-year-class larvae during a 30-day period; the results are consistent with passive (density-independent) colonization. A second field experiment examined the effect of large, second-year-class larvae at densities of 1 or 3 per cylinder (14 or 42 m-2) on colonization by small larvae; this colonization was inhibited at the high density of large larvae. In the laboratory experiment, when larvae of the two size-classes were together in the same aquarium, small larvae moved around less than when by themselves (dispersal inhibition). Thus the inhibition of colonization observed in the field may result from interference mortality, rather than from a flight response to the presence of larger conspecifics. To evaluate this interpretation, the third field experiment measured the in-situ functional response of large larvae to each other and to their small conspecific prey. Results suggest a type 1 (linear) functional response, with feeding inteference among large larvae. Moreover, the interference mortality inflicted by larger larvae on smaller conspecifics was apparently more intense on larger individuals within the small size-class. Taken together, the three field experiments and a statistical power analysis show how colonization and interference interact to determine the local density of small larvae, and why such interference effects are difficult to detect experimentally in the field.
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    URL: http://dx.doi.org/10.1007/BF00378720
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    On classifying interactions between populations (1987)
    Springer
    Oecologia 73 (1987), S. 272-281 
    Details
    ISSN: 1432-1939
    Keywords: Competition ; Interaction ; Mutualism ; Predation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The classification of interspecific interactions can have an important impact on ecologists' world views. Previous classifications have often been incomplete, have suffered from ambiguously defined categories, and/or have wrongly equated categories of population level effects with particular mechanisms of interaction. I use several simple mathematical models to argue that effects on short-term population growth rate, long term population size, and short term relative fitness of interactants may differ qualitatively. Equating all (--) effects with competition and all (+-) effects with predation may have caused ecologists to ignore a variety of potentially important interaction mechanisms. Failure to define the type of effect used in classifying interactions has led to confusion about the nature of interactions; several controversies regarding competition have apparently been caused or exaccerbated by problems with definition or clasification. In applying classification schemes, ecologists should realize that the classification of an interaction between two populations may change with the sizes of those populations or of other populations with which they interact.
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    URL: http://dx.doi.org/10.1007/BF00377518
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    Biomass production and nitrogen content of C3- and C4- grasses in pure and mixed culture with different nitrogen supply (1987)
    Springer
    Oecologia 71 (1987), S. 613-617 
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    ISSN: 1432-1939
    Keywords: Nitrogen use efficiency ; C3 grasses ; C4 grasses ; Biomass production ; Competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two C3 grasses (Hordeum vulgare L., Avena sativa L.) and two C4 grasses (Panicum miliaceum L., Panicum crus-galli L.) were cultivated in standard soil in the open air in pure cultures and in various mixed cultures at low and high nitrogen fertilization levels. After three months the dry weight, length and nitrogen content of the aboveground and below-ground parts of the plants and the shoot/root ratios were determined. Hordeum vulgare was the most successful species irrespective of the nitrogen fertilization level, and also exhibited in most cases the highest nitrogen concentrations. Panicum miliaceum, on the other hand, was the species least able to compete. The production of biomass was reduced in cultures growing under nitrogen starvation conditions, this phenomenon being more pronounced with respect to the C4 than to the C3 species. The decrease in the production of biomass at low N conditions was most drastic with Panicum crus-galli, the species with the lowest nitrogen content and thus assumed to be best adapted to nitrogen starvation conditions. In cultures growing at low nitrogen fertilization levels the shoot/root ratios of all species.shifted in favour of an increasing root proportion. The extent of this shift, however, differed from species to species.
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    URL: http://dx.doi.org/10.1007/BF00379307
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    Dietary shifts, niche relationships and reproductive output of coexisting Kestrels and Long-eared Owls (1987)
    Springer
    Oecologia 74 (1987), S. 277-285 
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    ISSN: 1432-1939
    Keywords: Diet breadth ; Overlap ; Competition ; Kestrel ; Long-eared Owl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Food samples of breeding Kestrels (Falco tinnunculus) and Long-eared Owls (Asio otus) were collected in the peak and low phase of their preferred prey (Microtus voles) in western Finland. Diets of pairs that bred as neighbours (≤1 km) with interspecifics were compared with those of non-neighbours. In both species, neighbouring pairs fed less on Microtus voles and more on alternative prey than did non-neighbours. Competition theory predicts that diet overlap should be lower during prey shortage and that diet similarity should be especially reduced in neighbouring pairs. Observations were consistent with expectations: diet similarity was lower in the low vole years and neighbouring pairs showed less diet overlap that non-neighbours. Differences in habitat composition and prey availability at the sample sites should not confuse the results. In addition to the high diet similarity, hunting habitats and nest sites of the species overlapped almost completely; they only showed clear temporal segregation in hunting. Probably because of food competition, the neighbouring pairs of both species produced significantly fewer young than the non-neighbours. These results contrast with the view that the diet composition and dietary shift of rodent-feeding predatory birds can be interpreted in terms of simple opportunistic foraging. In the breeding season, interspecific competition for food seems to be an important factor that affects the niches of these species, especially in northern areas, where the seasonal low phase of voles in spring and the number of alternative prey are lower than in more southern areas.
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    URL: http://dx.doi.org/10.1007/BF00379371
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    Changes in interacting species with disturbance (1987)
    Springer
    Environmental management 11 (1987), S. 257-264 
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    ISSN: 1432-1009
    Keywords: Disturbance ; Exploitation ; Competition ; Extirpations ; Species diversity and stability ; Boreal forest ; National park ; Endangered species ; Predator-prey relationships ; Restoration of fauna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Human-influenced changes in the diversity and abundance of native wildlife in a southern boreal forest area, which became a national park in 1975, are used to develop working hypotheses for predicting and subsequently measuring the effects of disturbance or restoration programs on groups of interacting species. Changes from presettlement conditions began with early 1900 hunting, which eliminated woodland caribou (Rangifer tarandus) and elk (Cervus elaphus), and reduced moose (Alces alces) to the low numbers which still persist. Increases in white-tailed deer (Odocoileus virginianus), as these other cervid species became less abundant or absent, provided enough alternative food to sustain the system's carnivores until plant succession on previously burned or logged areas also caused deer to decline. With increased competition for reduced food, carnivore species also became less abundant or absent and overexploited some prey populations. The abilities of interacting species to maintain dynamically stable populations or persist varied with their different capacities to compensate for increased exploitation or competition. These relationships suggested a possible solution to the problem of predicting the stability of populations in disturbed systems. For the 1976–1985 period, a hypothesis that the increased protection of wildlife from exploitation in a national park would restore a more diverse, abundant, and productive fauna had to be rejected.
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    URL: http://dx.doi.org/10.1007/BF01867204
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    Equilibria in systems of interacting structured populations (1987)
    Springer
    Journal of mathematical biology 24 (1987), S. 627-649 
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    ISSN: 1432-1416
    Keywords: Communities of structured populations ; Equilibria ; Stability ; Bifurcation ; Interacting species ; Competition ; Predator-prey inter-actions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract The existence of a stable positive equilibrium density for a community of k interacting structured species is studied as a bifurcation problem. Under the assumption that a subcommunity of k−1 species has a positive equilibrium and under only very mild restrictions on the density dependent vital growth rates, it is shown that a global continuum of equilibria for the full community bifurcates from the subcommunity equilibrium at a unique critical value of a certain inherent birth modulus for the kth species. Local stability is shown to depend upon the direction of bifurcation. The direction of bifurcation is studied in more detail for the case when vital per unity birth and death rates depend on population density through positive linear functionals of density and for the important case of two interacting species. Some examples involving competition, predation and epidemics are given.
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    An efficient procedure for extraction and determination of steroids in the tissue of laboratory animals (1987)
    Springer
    Chromatographia 23 (1987), S. 796-802 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Steroids ; Rat tissue ; Purification by extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A high-performance liquid chromatographic method for analysis of steroids in the tissue of laboratory animals is described. A two-stage solid extraction procedure, utilizing Sep-pak C18 and graphitized carbon black, gives a purified product. Steroids in this extract were separated by multistep gradient elution with a reversedphase liquid chromatography system, using acetonitrilewater as solvent. Several columns with different geometry and phase loading were investigated. Optimum resolution was obtained with a medium covered and spherical particle. The applicability of this method was successfully demonstrated in the analysis of the testis and adrenal gland of rat.
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    HPLC of aminoacids on silica coated with ammonium tungstophosphate (1987)
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    Chromatographia 23 (1987), S. 814-817 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thin layer chromatography ; Ammonium tungstophosphate ; Aminoacids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The chromatographic behaviour of aminoacids on columns of silica coated with different percentages of ammonium tungstophosphate at several buffer phosphate concentrations is reported. The stationary phase shows a high selectivity towards aminobutyric acids and methyl derivatives of tryptophan due to the distance between the carboxylic group and the −NH 3 + group involved in the cation-exchange process and/or to the steric hindrance by a methyl substituent. A relationship between HPLC and HPTLC data has been verified and applied to the prediction of the separation of six aminoacids.
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    Limits of determination and calibration in HPLC (1987)
    Springer
    Chromatographia 23 (1987), S. 934-938 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Calibration ; Confidence interval ; Limit of determination ; Limit of calibration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In HPLC calibration the expressions lowest calibration limit and determination limit are defined in statistical terms. The lowest calibration limit is the minimum mass in the measured series of calibration points. It is calculated from the confidence interval of the inverse of the calibration function as the lowest mass limit that may be differentiated from zero mass with a preset probability of error. If the calculated lowest calibration limit is lower than the actual data, points at lower concentration may be measured. The determination limit is the smallest concentration of an analysis that is differentiated from the concentration zero or an apparent blind value in the calibration curve with a given probability of error. Using two different UV-detectors (variable wavelength and photodiode-array) the lowest calibration limit is experimentally evaluated and compared with specific data for the detectors.
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    Sub-nanogram detection of dihydroartemisinin after chemical derivatization with diacetyldihydrofluorescein followed by high-performance liquid chromatography and UV absorption (1987)
    Springer
    Chromatographia 23 (1987), S. 112-114 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Pre-column derivatization ; Ultraviolet detector sensitivity ; Dihydroartemisinin ; Diacetyldihydrofluorescein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of diacetyldihydrofluorescein (DADF) for derivatization of dihydroartemisinin (dihydroqinghaosu, DHQHS) is proposed. The reaction between DHQHS and this reagent in the presence of 4-dimethylaminopyridine (DMAP) and N,N′-dicyclohexylcarbodiimide (DCC) was complete in 8 hours at room temperature giving about 80 per cent theoretical yield. The derivative showed intense UV absorption, thus providing a sensitivity of 0.1 nanogram by UV detection after column separation. The influences of the ratio of the reagents, reaction temperature, chromatographic conditions and the extent of detection linearity were investigated. The reaction gave consistent results and chromatographic separation was not affected by an excess of the reagent or side products.
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    HPLC in photokinetics: Determination of reaction mechanism and photochemical quantum yields of (E)-1-phenylpropene (1987)
    Springer
    Chromatographia 23 (1987), S. 395-400 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Photokinetic data ; Reaction mechanism ; (E)-1-phenylpropene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A combined method of high-performance liquid chromatography and UV-absorption spectroscopy is described for use in dynamic systems. It provides a way of obtaining detailed mechanistic information as well as quantitative data (rate constants, quantum yields), even though neither mechanism nor photoproducts are known. The kinetic treatment of the photoreaction of (E)-1-phenylpropene was successful, showing a photo-isomerization and a parallel step. Information on this additional step is obtained by using HPLC to observe the changes in the concentrations of the reactants' selectivity. The necessity of process control is demonstrated.
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    Determination of particulate fatty acids as P-bromophenacyl- or phenylphenacylesters using HPLC (1987)
    Springer
    Chromatographia 23 (1987), S. 419-422 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Fatty acid esters ; Particulate material in seawater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method for the determination of fatty acids of the molecular weight range of propionic to erucic acid is reported. The acids are converted to either p-bromophenacyl-or p-phenylphenacylesters and the esters are separated by HPLC and detected by UV-absorption. Twentytwo esters, including saturated, monoolefinic and polyunsaturated ones were separated within one HPLC-run. The detection limit is about 5 pmol per fatty acid. The application of the method to particulate material is described.
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    New polymer coated anion-exchange HPLC-phases: Immobilization of poly (2-hydroxy, 3N-ethylenediamino) butadiene on silica and alumina (1987)
    Springer
    Chromatographia 23 (1987), S. 435-441 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Anion-exchange stationary phases ; Polymer coating ; Cross-linking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary PHEB=POLY(2-hydroxy, 3N-ethylenediamino)butadiene has been synthesized. This unsaturated pre-polymer can be immobilized on different, preferably inorganic supports of suitable porosity such as silica or alumina by cross-linking. Weak anion-exchange phase are obtained. Such phases do not have the disadvantages of organic polymeric phases, regarding pressure stability and swelling by solvent influence. The ion-exchange capacity and the retentivity of IE-separations can deliberately be varied via the thickness of the cross-linked polymer layer. Alumina can also be coated with PHEB applying the same cross-linking procedure. Such phases exhibit an exceptional chemical stability even when operated with mobile phases at very high pH-values. Separations of excellent selectivity are achieved for inorganic anions, as well as with mixtures of aliphatic and aromatic free acids also including hydroxy- (mono- or poly)carboxylic acids.
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    Application of the electrostatic interaction concept for the study of the retention behaviour of peropyrene-type polycyclic aromatic hydrocarbons in reversed-phase liquid chromatography (1987)
    Springer
    Chromatographia 23 (1987), S. 473-476 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed-phase systems ; Stationary phase-solute interactions ; Polycyclic aromatics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Capacity factors of peropyrene-type polycyclic aromatic hydrocarbons were measured using 15 different liquid chromatographic reversed phase systems. On the basis of the retention data the electric interaction indices have been calculated. Application of these indices for structure-retention studies on peropyrene-type polycyclic aromatic hydrocarbons is demonstrated.
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    Separation of gonadal steroid epimers using high performance liquid chromatography (1987)
    Springer
    Chromatographia 23 (1987), S. 31-32 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gonadal steroids ; Epimers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Chromatographic separation of biologically active epimeric steroids was carried out using a combination of normal and reversed phases. Testosterone (17β-OH) was separated from its 17α-OH epimer epitestosterone using a normal phase silica column whereas their reduced 5α-metabolites were separated on a reversed phase system. The separation of other gonadal steroids including the epimers 20α- and 20β-hydroxypregn-4-en-3-one is also discussed. The technique is particularly useful for separating mixtures of naturally occurring steroid epimers prior to radioimmunoassay.
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    Separation of chlorophylls and their degradation products in marine phytoplankton by reversed-phase high-performance liquid chromatography (1987)
    Springer
    Chromatographia 23 (1987), S. 26-30 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ammonium acetate buffer eluent ; Chlorophylls and degradation products ; Marine phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An RP-HPLC procedure which separates chlorophylls and their degradation products is described. By employing an amonium acetate buffered mobile phase and a linear gradient elution, complex mixtures of chloroand phaeopigments are separated in less than 30 minutes. The method has been applied to the control of chlorophyll enzymatic degradation in cultures of two algal species, and has also been successfully used in the analysis of algal xanthophylls.
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    Reversed-phase HPLC behaviour of metal complexes with 4-(2-pyridylazo) resorcinol. A detailed study in the light of solvophobic theory (1987)
    Springer
    Chromatographia 23 (1987), S. 736-746 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Behaviour of metal complexes ; Solvophobic theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The chromatographic behaviour of Cu(II), Fe(II), Ni(II) and Co(II) complexes with 4-(2-pyridylazo)resorcinol was studied. The experimental results were very sensitive even to less obvious operational parameters like the kind of the cation (sodium or ammonium) of the phosphate salt used as buffer. The puzzling pattern of the data obtained was interpreted in terms of the equations formulated by Horvath's ‘olvophobic” theory which correlates the capacity factors of the solutes with the surface tension of the mobile phase. A satisfactory rationalization of the data was obtained together with qualitative information on the stoichiometry and charge state of metal complexes. Useful suggestions about the direction to address the experimental work in order to obtain the best results was also obtained.
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    Separation of transition metal ions and preconcentration of platinum (IV) and chromium (III) on alumina-immobilized diethylenetriaminepentaacetic acid by ligand exchange (1987)
    Springer
    Chromatographia 23 (1987), S. 747-751 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ligand Exchange ; Diethylenetriaminepentaacetic acid ; Transition metal ion separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Basic alumina-bonded diethylenetriaminepentaacetic acid (DTPA) has been utilized for the separation and preconcentration of some transition metal ions on the basis of ligand exchange. Breakthrough capacity and rate of sorption have been studied. The distribution coefficients of 16 transition metal ions have been determined in demineralized water, 0.01 M sodium citrate and in four different pH systems. On the basis of differences in Kd values some quantitative separations of metal ions have been achieved. The greater selectivity behaviour (higher Kd values) of the adsorbent for Pt(IV)and Cr(III) has been utilized for their preconcentration in the presence of other metal ions. The method has been employed for the recovery of Pt(IV) and Cr(III) from tapwater and sea-water samples.
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    Gel filtration and high-performance liquid chromatographic analysis of phosphotungstic acid soluble peptides from blue cheeses (1987)
    Springer
    Chromatographia 23 (1987), S. 764-766 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gel permeation chromatography ; Cheese peptides ; Amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The nitrogen fraction from cheese, soluble in phosphotungstic acid has been analyzed by gel permeation and high performance liquid chromatography. Elution profiles of this fraction on Sephadex G-10 show that there are no peptides of molecular weight higher than 700 daltons. Six fractions have been obtained. The first one has the peptides and some amino acids. Fractions II to VI contains mostly free amino acids. Fraction I has been separated into many peaks by HPLC. Six or seven of these peaks are presumed to correspond to peptides.
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    Preparation and performances of small bore columns packed with reversed-phase materials and their use for the evaluation of air pollutants (1987)
    Springer
    Chromatographia 23 (1987), S. 803-810 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Small-bore packed columns ; Air pollutants ; PAH, nitro and oxy-PAH ; Aldehydes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The preparation of small bore columns (1 mm i.d.) packed with reversed-phase materials is described. High efficiency (Hmin=2 dp), coupled with a small C term (0.005 sec) have been obtained so that high speed can be combined with sufficient resolution for the separation of complex organic mixtures. These columns have been used for the separation of air pollutants dispersed in different matrices (air, particulate matter and rain water). Practical applications include the determination of aldehydes in air and emission samples, PAHs, nitrated and oxygenated PAHs in dust sampled from the stack of an industrial emission or collected in a urban area and the analysis of organic components dissolved in rain water collected at a rural site. Specific detection of these pollutants has been achieved by connecting small bore columns to UV absorbance, voltammetric and fluorimetric detectors. Mass spectra of some specific components have been recorded using the off-line technique.
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    HPLC determination of the aromatic fraction of gasoline (1987)
    Springer
    Chromatographia 23 (1987), S. 825-828 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gasoline ; Single-ring aromatic hydrocarbons ; Polycyclic aromatic hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This work reports a rapid and easy procedure for the analysis of the aromatic fraction in gasoline. No sample pretreatment is required, since the gasoline is diluted in methanol and directly injected into a liquid chromatograph. A spectrophotometer detector and a spectrofluorimeter detector are used in series. The procedure has been applied to a large number of Italian and European refined gasoline samples.
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    Separation of aldicarb, aldicarb sulfoxide, and aldicarb sulfone on unmodified silica with reverse-phase eluents (1987)
    Springer
    Chromatographia 23 (1987), S. 109-111 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Normal and reverse phase ; Aldicarb ; Aldicarb sulfoxide ; Aldicarb sulfone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Aldicarb, aldicarb sulfoxide, and aldicarb sulfone were chromatographed on an octyl-silica bonded-phase column and on an unmodified silica column using acetonitrile/water mobile phases. The elution order of the analytes from the silica column was different from that using the octyl-silica bonded phase and allowed confirmation of residues of aldicarb sulfoxide in citrus nectar. Isocratic elution of the unmodified silica column allowed rapid sample throughput.
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    High-performance ligand exchange chromatography on chiral diamine-bonded silica gel (1987)
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    Chromatographia 23 (1987), S. 118-120 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ligand-exchange chromatography ; Chiral bonded phase ; Racemate resolution ; Amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The resolution of racemates on chiral chemically bonded silica gel by high-performance ligand-exchange chromatography is described. The stationary phase was prepared by bonding (−) trans 1,2 cyclohexanediamine to silica gel through the coupling agent 3-glycidoxypropyl silane. The resolution of several α-amino acids and of compounds of pharmaceutical interest is reported.
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    Relative importance of factors controlling the success of Oxalis acetosella: an example of linear modelling in ecological research (1987)
    Springer
    Plant ecology 70 (1987), S. 171-179 
    Details
    ISSN: 1573-5052
    Keywords: Competition ; Forest ecology ; Indicator species ; Linear models ; LISREL ; Oxalis acetosella ; Path analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An ecological hypothesis concerning the relative importance of factors governing the success of Oxalis acetosella on mesic upland forest sites in southern Finland was formulated and tested statistically by means of a multivariate linear model. The data consisted of a stratified random sample of 40 plots with biological measurements and associated observations on environmental variables. The covariance matrix between the incorporated variables was computed and the model parameters were estimated using the method of maximum likelihood provided by the computer programme LISREL V. The results supported the hypothesis based on previous observations and experiments: Oxalis acetosella benefits from a high nutrient level of the soil, but is decisively dependent on the shelter provided by the tree stand. When both spruce stands and well-lit pine stands on mesic and relatively rich forest sites were considered simultaneously, only a weak correlation was found between light availability and site fertility. Accordingly, the presumed value of Oxalis acetosella as an indicator of site fertility appears to be questionable. The adequacy of linear modelling in an ecological context is discussed. The kind of models applied in this study have only a limited application range in non-experimental ecological research. However, linear modelling may contribute to solving particular ecological problems in cases where short environmental gradients are considered so that nonlinearity is not a dominant feature.
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    URL: http://dx.doi.org/10.1007/BF00039330
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    Sibships: Cooperation and competition among immature vervet monkeys (1987)
    Springer
    Primates 28 (1987), S. 47-59 
    Details
    ISSN: 0032-8332
    Keywords: Sibling ; Cercopithecus aethiops ; Competition ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationships between siblings were compared with those between non-sibling peers amongst immature vervet monkeys (Cercopithecus aethiops) in three free-ranging social groups. Using the frequency and context of friendly, supportive, aggressive, and competitive interactions, sibships were found to stand out as associative units characterized by high levels of grooming and support during aggression. Competition between siblings was related to contests over access to maternal care, especially grooming, which may have been important in the establishment of relative sibling dominance. Siblings who were close in age tended to interact more frequently than those who were distant in age, but few sex differences were found. The close and supportive nature of sibling relationships appeared to affect the social structure of the groups.
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    URL: http://dx.doi.org/10.1007/BF02382182
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    Diet of alewives, Alosa pseudoharengus and blueback herring, A. aestivalis (Pisces: Clupeidae) in Minas Basin, Nova Scotia, a turbid, macrotidal estuary (1987)
    Springer
    Environmental biology of fishes 19 (1987), S. 55-67 
    Details
    ISSN: 1573-5133
    Keywords: Co-existing sibling species ; Feeding behaviour ; Vertical segregation ; Size class ; Competition ; Dietary importance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Stomach contents of anadromous alewives, Alosa pseudoharengus and blueback herring, A. aestivalis, obtained from brush weir and drift net collections in Minas Basin, N.S., were examined. Diets showed much overlap in terms of resource use, but the dietary importance of major prey categories differed substantially between species. Alewives favoured larger, more benthic prey (e.g. amphipods, mysids and crangonids), while blueback herring appeared to concentrate their feeding on microzooplankters (e.g. calanoid copepods, cypris larvae and molluscan veligers). Interspecific differences in diet composition are largely attributed to the planktivorous feeding habits of small (81–155 mm fork length) blueback herring. Differences in prey suggest that alewives utilize a particulate feeding strategy while blueback herring are predominantly filter-feeders. Although competition for food in the Basin seems unlikely since high secondary production yields a superabundance of prey, differences in feeding behaviour between younger, smaller individuals of both species could be a means of avoiding competitive interactions in an environment where there are space/access limitations imposed by the tidal cycle.
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    URL: http://dx.doi.org/10.1007/BF00002737
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    Ecology of survival in some gadoid larvae of the northern North Sea (1987)
    Springer
    Environmental biology of fishes 19 (1987), S. 241-260 
    Details
    ISSN: 1573-5133
    Keywords: Mortality ; Growth ; Prey density ; Prey size ; Spawning period ; Production cycle ; Competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The development of the larvae of five gadoid species in the northern North Sea was examined in May 1978 and May 1979. Mortality varied with larval size and period of sampling about high average rates. The limits on survival were due primarily to prey density and prey size. Competition for food did not appear to be a critical survival factor. The growth rates of larvae in the northern North Sea were higher than the growth rates of larvae reared on high densities of prey in the laboratory. Without involving the hypothesis of patchiness, it is suggested that sufficient quantities of prey were available in the field to sustain the high growth rates observed. On the other hand, competitive grazing in the laboratory reduced the amount of prey which fell to the share of each larva. Scarcity of large prey during the first half of May did not favour the survival of late larvae. The significance of spawning in relation to the characteristics of the prey production cycle is discussed.
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    URL: http://dx.doi.org/10.1007/BF00003226
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    Inoculation of pea by application of Rhizobium in the planting furrow (1987)
    Springer
    Plant and soil 97 (1987), S. 63-70 
    Details
    ISSN: 1573-5036
    Keywords: Competition ; Indirect inoculation ; Inoculum rate ; N2 fixation ; Pisum sativum ; Rhizobium leguminosarum ; Streptomycin resistant mutants ; Yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Selected streptomycin resistant strains ofRhizobium leguminosarum suspended in nutrient broth were added to the planting furrow immediately before the sowing of pea. The nodule occupancy by a strain isolated from Risø soil (Risø la) was increased from 74 to 90%, when the inoculum rate was increased from 3.7×106 to 3.7×108 cells per cm row. The experimental soil contained 103 to 104 cells ofR. leguminosarum per gram. An almost inefficient strain isolated from Risø soil (SV10) was less competitive with respect to nodulation on two pea cultivars than an efficient Risø strain (SV15) and an efficient non-Risø strain (R1045). The nodule occupancy by the introduced strains varied between pea cultivars. Irrespective of the generally high nodulation by the efficient strains introduced to the soil, the pea seed yield, compared to pea nodulated by the indigenous population, was not significantly increased. Neither were two commercial inoculants, applied in rates corresponding to 3 times the recommended rate, able to increase the yield. This suggests that the indigenous populations ofR. leguminosarum were sufficient in number and nitrogen fixing capacity to ensure an optimal pea crop. However, some inoculation treatments slightly increased the seed N concentration and total N accumulation, indicating that it may be possible to select or develop bacterial strains that may increase the yield.
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    URL: http://dx.doi.org/10.1007/BF02149824
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    Experiments on competitiveness of three endomycorrhizal fungi (1987)
    Springer
    Plant and soil 97 (1987), S. 155-170 
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    ISSN: 1573-5036
    Keywords: Colonisation pattern ; Competition ; Gigaspora margarita ; Glomus fasciculatum (E3) ; Glomus tenue ; Growth effects ; Positional effects ; Sorghum vulgare ; Trifolium repens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary This paper examines competition between three VA endophytes places respectively as “inoculant” fungus in an inner compartment (300 ml) below the germinating seed, and as “indigenous” fungus in an outer compartment (900 ml). Previously prepared infested soil was used as source of the endophytes. Inner and outer compartment roots were harvested separately and percentage infection determined for each fungus, using diagnostic anatomical features of each fungus. Changes in colonisation patterns were followed up to 4 and 5 months. Treatments with non-infested soil in the outer compartment were used to compare infectivity and spread of the different endophytes. All three endophytes were able to invade soil already colonised by either of the other two, butGlomus fasciculatum (E3) was more invasive thanGlomus tenue. This pattern appeared to be related to rates of spread of the fungi in the non-infested soil. The pattern was not affected by host, clover or sorghum, or by position, immediately below the seed or in the outer compartment. It seemed that the endophyte in the inner compartment had overriding and persistent effects on plant growth, unrelated to its dominance pattern or share of overall root infection at the later harvests.
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    URL: http://dx.doi.org/10.1007/BF02374938
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    Effect of spore concentration on germination and autotropism inTrichoderma hamatum (1987)
    Springer
    Plant and soil 100 (1987), S. 285-295 
    Details
    ISSN: 1573-5036
    Keywords: Competition ; Germtube emergence ; Inhibitory compounds ; Nutrients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effect of spore concentration on spore germination and germtube growth ofTrichoderma hamatum on water agar and on potato dextrose agar (PDA) was studied. Increasing inoculum size up to 109 spores/plate on PDA and up to 107 spores/plate on water agar shortened the incubation period required for germtubes emergence and increased germination rate. However, on water agar germination was inhibited at 108 and was completely arrested at 109 spores/plate. Inhibition in germination of 107 spores/plate was observed on water agar when the plates were preincubated with 109 spores/plate for 5 h or more. Addition of glucose and ammonium nitrate to the water agar medium allowed only 25% of the spores to germinate at 109 as compared to 78% at 107 spores/plate after 8 h of incubation. Addition of polysaccharides to the C+N supplemented medium, significantly increased germination up to 84% as compared to 100% on PDA, after 8 h of incubation. Germlings ofTrichoderma hamatum phialospores exhibited positive autotropism and anastamosis on both media. The phenomenon was positively related to inoculum size, being most pronounced at 107 spores/plate.
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    URL: http://dx.doi.org/10.1007/BF02370946
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    Habitat use of arctic charrSalvelinus alpinus in Thingvallavatn, Iceland (1987)
    Springer
    Environmental biology of fishes 20 (1987), S. 263-274 
    Details
    ISSN: 1573-5133
    Keywords: Charr morphs ; Habitat segregation ; Competition ; Predation ; Trophic specialization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Habitat use by four morphs of arctic charr,Salvelinus alpinus, was investigated in Thingvallavatn, Iceland, by sampling with pelagic and benthic gill nets. Sampling was done in May/June and August/September. Greatest abundance of fish was recorded in the littoral and epipelagic zone in early autumn. Catches were low in early summer. The four morphs are partly segregated in habitat. Small (SB-) and large benthivorous (LB-) charr have a more restricted spatial distribution than piscivorous (PI-), and especially planktivorous (PL-) charr. Both benthivorous morphs are mainly found in the littoral zone, and occur in largest numbers in stony shallows at depths between 0 and 10 m. PL-charr usually dominates in numbers in all habitats. PI-charr is most abundant in epibenthic habitats, although numbers are always low. All morphs are caught in higher numbers at night than during the day, but the diurnal activity difference is highest among SB-charr. The habitat use by different morphs is as may be expected from their morphology and diets. Within the population of PL-charr, young and small fish are more abundant on the bottom than in the pelagic zone, and there is a surplus of females in the pelagic zone. Along the benthic profile, young, small and immature PL-charr are more abundant in deep than in shallow waters. The results are discussed in relation to food supply, competition and predation. Possible reasons for the occurrence of four arctic charr morphs are also discussed.
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    Optimization of fat soluble vitamin separation in reversed-phase microcolumn liquid chromatography (1987)
    Springer
    Chromatographia 23 (1987), S. 320-324 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Microbore capillary columns ; Polymer based octadecylsilica bonded phase ; Fat soluble vitamins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Separation behavior of fat soluble vitamins on various chemically bonded materials in non-aqueous reversedphases microcolumn liquid chromatography has been investigated. The best performance was found on a polymer-based octadecyl bonded phase. Optimization of separation for vitamins D2, D3, E and E acetate has been tried using this polymer-based column and it has been found that a binary mobile phase consisting of acetonitrile and methanol gave complete separation of fat soluble vitamins.
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    URL: http://dx.doi.org/10.1007/BF02316175
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    A comparative study of large volume injection techniques for microbore columns in HPLC (1987)
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    Chromatographia 23 (1987), S. 331-336 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Microbore columns ; Injection techniques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This paper focuses attention on the potentially larger signal-to-noise ratios produced by microbore columns in comparison with conventional columns. The increased chromatographic signals by the application of microbore columns are due to the lower chromatographic dilution of elution profiles which are proportional to the square of the column inner radius. Generally less than 1μl sample should be injected into microbore systems to obtain the full benefit of the column performance. However, since more sample can be loaded on conventional columns compared to microbore columns the advantage of improved signal-to-noise ratio can only be realised in situations where very little sample is available. To inject more than 1μl sample, at the same time avoiding extra band-broadening effects, suitable injection techniques must be available. In this study three injection methods for microbore systems that meet this condition, are studied and compared.
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    High-performance liquid chromatography using a color-forming agent as a component of the mobile phase. Separation and determination of nickel and zinc wity xylenol orange (1987)
    Springer
    Chromatographia 23 (1987), S. 355-360 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Anion-exchange chromatography ; Xylenol orange ; Separation of nickel and zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A liquid chromatographic procedure for separating nickel and zinc has been developed. Xylenol orange, which is one of the sensitive and commercially available color-forming agents, was used as a component of the mobile phase. The two ions could be separated on weak anion-exchange gels within 10 min. The procedure was suitable for the determination of nickel and zinc in relatively pure solutions with fairly high sensitivity. The described liquid chromatographic analysis would be also potentially applicable for any aqueous sample containing trace levels of metal cations at 1–10 ppm.
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    Determination of oligosaccharides (DP1-DP8) in samples with high content of salt and organic matter by reversed phase HPLC (1987)
    Springer
    Chromatographia 23 (1987), S. 557-560 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Oligosaccharides ; Interference by salts ; Complex biological samples ; Enzymatic assays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the determination of oligosaccharides in samples of high salt content by RP-HPLC with water as eluent and refractive index detection. The samples, mussel processing wastes which are used as media for microfungus and yeast cultures and hence for enzymatic assays (amilolitic capacity) of these microorganisms that develop within the wastes, have been treated with ethanol to precipitate the macromolecular organic matter and desalted by a modified mixed bed resin before chromatographic analysis is carried out.
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    Group-type separation and determination of phenolic compounds in coal-derived products by HPLC (1987)
    Springer
    Chromatographia 23 (1987), S. 579-582 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Backflush technique ; Coal-derived procucts ; Separation of phenolic compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A rapid method was developed for the direct extraction of phenolic compounds from coal-derived products and subsequent isocratic HPLC analysis in a reversed-phase system by using the backflush technique.
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    High-performance liquid chromatography using a color-forming agent as a mobile phase component. Separation of alkaline-earth-metal cations with arsenazo III and a non-porous gel column (1987)
    Springer
    Chromatographia 23 (1987), S. 583-589 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Non-porous gel ; Alkaline-earth cations ; Arsenazo III
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A liquid chromatographic procedure for separating alkaline-earth-metal cations with a non-porous gel column has been developed. Arsenazo III, which is one of the sensitive and commercially available color-forming agents, was used as a component of the mobile phase. Magnesium and calcium could be separated on the nonporous gel column within 55 seconds. The procedure was suitable for the separation of alkaline-earth-metal cations in relatively pure solutions with high sensitivity. Because of its rapidity the described procedure is also potentially applicable for any aqueous sample.
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    High-performance liquid chromatography of biphenols and bis (hydroxyphenyl) propanes (dianes) with voltammetric and UV photometric detection (1987)
    Springer
    Chromatographia 23 (1987), S. 102-108 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Biphenols ; Dihydroxyphenylpropanes ; Voltammetric detection ; UV photometric detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention behaviour of mono- and dihydroxy derivatives of biphenol and bis(hydroxyphenyl)propanes was studied on chemically bonded C-18, CN-, phenyl, phenoxypropyl- and NH2 stationary phases and on silica gel. The effects of the mobile phase, i.e., of the methanol content, the ionic strength, pH and the contents of cationic and anionic ion-pairing agents on the retention data were investigated. In the reversed-phase systems, all the substances are satisfactorily separated except for 3- and 4-hydroxybiphenyl; these isomers can be separated on silica gel, using a mixture of heptane and propanol as the mobile phase. Sodium dodecylsulphate, present at concentrations higher than the critical micelle concentration (about 10−2 M, depending on the methanol content), causes a decrease in the retention times and an improvement in the separation. UV absorption spectra, calibration curves and the detection limit values were obtained at two wavelengths and at various salt concentrations in the mobile phase. Hydrodynamic voltammograms of the solutes were measured in a carbon fibre detector and the calibration curves and detection limit values were measured at the optimal voltage (+1.2 V/Ag/AgCl) as a function of the mobile phase composition. For most test substances voltammetric detection is two to three times more sensitive than UV detection. The combination of a UV and a voltammetric detector in series has been utilized to identify the products of microbial degradation of biphenyl.
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    Reversed-phase ion-pair systems to predict partition coefficients of β-carbolines by HPLC and TLC (1987)
    Springer
    Chromatographia 23 (1987), S. 713-716 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thin-layer chromatography ; Ion pairing system ; Log P prediction ; Group contributions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A group of 17 β-carbolines was studied in HPLC and TLC systems in order to predict their partition coefficients (log P values). On account of the basic or acid character of some of these compounds, an ion pairing system gave the best results. Both HPLC and TLC data were comparable for log P prediction but severe pH conditions required the use of TLC plates. Retention data are quantitatively related to lipophilicity (expressed as the Hansch constant) and polarity (as the inductive constant) of the solute molecule.
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    Chitosan-coated silica gel as a new support in high-performance liquid chromatography (1987)
    Springer
    Chromatographia 23 (1987), S. 731-735 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chitosan-coated silica gel ; Nucleotides ; Amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new stationary phase was prepared by immobilizing the chitosan, a natural hydrophilic polymer, on microparticolate silica gel. The effect of the polarity, pH and ionic strength of the mobile phase has been studied in order to find optimal conditions for the separation of nucleotides and aminoacids. The influence of the properties of the mobile phase on the retention was examined, allowing to employ the chitosan-coated silica gel both to anion exchange and adsorption, depending on the pH and the polarity of the eluent used.
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    Qualitative description of dispersive and inductive electrostatic interactions in reversed-phase liquid chromatography (1987)
    Springer
    Chromatographia 23 (1987), S. 752-759 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed-phase systems ; Phases-solute interactions ; Molecular polarizability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Variations in the electrostatic interaction have been studied using polycyclic aromatic hydrocarbons as standard compounds and different reversed-phase HPLC systems. Various methanol-water and acetonitrile-water binary mixtures were applied as the mobile phase. The stationary phases investigated consist of octadecylsilica and arenyl-silica. Using polarizability, dipole moment and ionization potential values of the solutes and mobile phase components as molecular descriptors an electrostatic interaction model is proposed.
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    Ligand exchange separation of amines on copper (II) sorbed on zinc silicate (1987)
    Springer
    Chromatographia 23 (1987), S. 93-96 
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    ISSN: 1612-1112
    Keywords: Paper chromatrography ; Column liquid chromatography ; Copper-impregnated zinc silicate ; Separation of amines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Papers impregnated with Cu(II) sorbed on zinc silicate have been used to study the ligand exchange chromatographic behavior of amines. RF values of 16 amines have been studied in 6 different systems. On the basis of differences in RF values various analytically important qualitative separations of amines on impregnated papers and quantitative separations on columns of copper(II) sorbed on zinc silicate have been achieved.
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    URL: http://dx.doi.org/10.1007/BF02312880
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    Comparison of octadecyl-bonded silica and styrene-divinylbenzene copolymer sorbents for trace enrichment purposes fundamental aspects II. Linear chromatographic behaviour of the extracting supports (1987)
    Springer
    Chromatographia 23 (1987), S. 163-168 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Linear isotherms ; Octadecyl bonded silica ; Styrene divinylbenzene ; Frontal analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Two reversed-phase LC systems were investigated by frontal analysis for the determination of linear chromatographic conditions, as defined according to the isotherm concept. The Partisil ODS-3 bonded silica and the PRP-1 polystyrene-divinylbenzene resin were used as stationary phases together withtrans-2-hexen-al as test solute and methanol-water mixtures as mobile phases. Particular attention was paid to the respective influence of the two main parameters which may cause sorbent overloading, that is, the capacity factor (k′) and the solute concentration in the mobile phase (Cm). Provided that k′Cm≤10−2 M, linear chromatographic behaviour was observed for both sorbents, the maximum capacities of which were found greater than 1mmolg−1.
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    Estimation of the band broadening contribution of HPLC equipment to column elution profiles (1987)
    Springer
    Chromatographia 23 (1987), S. 189-194 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Instrument bandbroadening by extrapolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Methods to determine the contribution of the chromatographic equipment to the total band broadening which involve replacing the column by a union or a capillary tube are not suitable as they involve a fundamental change in the chromatographic system. The linear extrapolation method, based on the estimation of the relative influence of the instrument variance on solutes with different capacity factors, is a more attractive alternative method since the column remains in the chromatographic system. This method is only valid when a number of conditions are satisfied. By meeting these conditions the error in the instrument variance by using the linear extrapolation method was determined. At the same time, ways to minimise these errors were studied. Use of the linear extrapolation method in combination with conventional columns of 4.6 mm i.d. appears to yield inaccurate results. In combination with microbore columns the method can be used, provided the columns have a maximum length of 5cm and contain a packing material with a particle size of 2 or 3μm. The error in the determined instrument variance is then of the order of 2μl2.
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    Non-aqueous reverse-phase HPLC analysis of triglycerides (1987)
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    Chromatographia 23 (1987), S. 209-214 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Review of triglyceride analysis ; Column temperature gradients ; Combined LC and other techniques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The present review cites 54 papers dealing with reversephase HPLC analysis of triglycerides. The objective of the review was not merely to list the main contributions made in recent years but also to present a discussion of those papers representing qualitative advances and improvements helping to obviate the difficulties associated with this type of analysis. The use of mobile phase polarity and column temperature gradients and the combination of HPLC with other analytical methods such as mass spectrometry or GLC analysis of fatty acids are examples of such contributions.
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    Chromatographic packings made by solide phase synthesis (1987)
    Springer
    Chromatographia 23 (1987), S. 254-256 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Synthesis of stationary phases ; Influence of surface pH ; Influence of temperature, concentration and reaction ; time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new way to produce liquid chromatographic stationary phases is suggested. The method is based upon a solide-phase reaction between the silica surface and the adsorbed silane molecules. The role of surface pH is demonstrated. The influence of other reaction conditions (concentration of the silane solution, effect of temperature and reaction time) is discussed.
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    Preparation of chiral stationary phase via activated carbamate intermediate for liquid chromatographic optical resolution (1987)
    Springer
    Chromatographia 23 (1987), S. 727-730 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chiral stationary phases ; Succinimido carbamate intermediates ; Amino acid enantiomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Chiral stationary phases (CSPs) for liquid chromatography were prepared by the way of an activated carbamate intermediate. The amino group of aminopropylsilyl silica gel was first activated by carbamylation with disuccinimido carbonate (DSC). The obtained activated carbamate silica gel (ACsil) proved useful as an intermediate for the preparation of urea-type CSPs. The reaction of ACsil with (S)- of (R)-1-(α-naphthyl)-ethylamine gave naphthylethylurea type CSPs. These CSPs were also obtained directly from aminopropylsilyl silica gel by its reaction with optically active (S)- or (R)-succinimido 1-(α-naphthyl)ethyl carbamate (SINEC). Several phenylthiohydantoin amino acid enantiomers and p-bromophenylcarbamyl amino acid enantiomers were resolved on the CSPs by elution with aqueous mobile phase.
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    Determination of the concentration of silanol groups by a chemical reaction with methyllithium and GC measurements of evolved methane (1987)
    Springer
    Chromatographia 23 (1987), S. 767-769 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography ; Bonded silica ; Residual silanol groups
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Silanol groups of chromatographic material surfaces were determined by chemical reaction with methyl-lithium. Evolved methane was measured by a gas chromatographic method using a column packed with molecular sieves. This chromatographic technique leads to very reproducible results, particularly for the control of the hydroxylation of a silica gel and for the analysis of residual groups at the surface of bonded silica.
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    Determination of low boiling aldehydes in air and exhaust gases by using annular denuders combined with HPLC techniques (1987)
    Springer
    Chromatographia 23 (1987), S. 829-834 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Aldehydes ; Annular denuder ; Environmental analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An improved procedure for the HPLC determination of C1−C3 aldehydes in environmental samples is described. These air pollutants are quantitatively collected on annular denuders coated with 2,4-Dinitrophenylhydrazine and analyzed as hydrazone derivatives by HPLC with UV absorbance and voltammetric detection. Collection efficiencies of aldehydes are reported and compared with other available methods. Practical examples of the application of the method are given.
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    Assay for urinary estriol during the menstrual cycle based on extraction by a graphitized carbon black cartridge followed by high-performance liquid chromatography (1987)
    Springer
    Chromatographia 23 (1987), S. 835-838 
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    ISSN: 1612-1112
    Keywords: Estriol ; Urine ; Menstrual Cycle ; Column liquid chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A high-performance liquid chromatography (HPLC) assay for estriol in nonpregnancy urine is described. After Enzymic hydrolysis, the estriol is extracted from urine by the sorbent trap technique utilizing graphitized carbon black (Carbopack B). After some washing steps, estriol is desorbed by a suitable solvent system. After solvent removal, the sample is injected into an HPLC column for estriol quantification. Analytical recovery of estriol was 96.1%. The precision of the method was 2.6 and 4.9% respectively at 145 and 10.6ng/ml of urine. The limit of sensitivity was set at 0.8 ng/ml of urine. The mean contents of estriol in the follicular and luteal phases were respectively 11.3 and 38.8 ng/ml of urine.
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    Influence of column temperature, water content, polarity, and acidity of isohydric solvents on the separation of butyrophenones on silica gel (1987)
    Springer
    Chromatographia 23 (1987), S. 893-898 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Isohydric solvents ; Butyrophenones ; Direct-silica gel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The behaviour of butyrophenones in high performance liquid chromatography on silica gel using isohydric solvent systems has been studied. The influence of column temperature, water content, acidity and polarity of isohydric solvents on the retention, column efficiency and resolution of a series of butyrophenones have been investigated. Through the results obtained more insight has been gained into the theoretical aspects of the adsorption process on silica gel with isohydric solvent systems.
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    Large scale purification of synthesized oligodeoxyribonucleotides by reversed-phase chromatography (1987)
    Springer
    Chromatographia 23 (1987), S. 909-914 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed-phase separation ; Oligodeoxyribonucleotides ; Isolation of pure material
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A reversed-phase chromatographic column suitable for the purification of chemically synthesized large oligodeoxyribonucleotides (oligo-DNA) was prepared. The specifications of this column are; the selected silica (Toyo Soda silica) with large pore size (at least 150 Å) and small particle diameter (5 μm desired) should be grafted only with monochloro alkylating reagent of long alkyl chain (sufficiently C18) so that the carbon content of the resultant packing material is 15–16%. Using this column, we could isolate the targeted large oligo-DNA (up to 50mer) in a large scale (75 μg per one cycle) from the impurities in the reaction mixture formed during the automated synthesis by the phosphite method.
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    A critical review of some liquid chromatography systems for the separation of sugars (1987)
    Springer
    Chromatographia 23 (1987), S. 292-300 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Separation of sugars ; Review
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This contribution to the problems of carbohydrate (sugar) column liquid chromatography, evaluates several currently used systems (reversed phase octadecylated silica gel, amino modified silica gel, cation exchangers on polystyrene and on silica gel basis, polyol derivatised silica gel and anion exchange systems). The elution pattern, analysis time, column efficiency and column life time expectancy are considered to be the important points for this comparison. The application of silica gel-based cation exchanger and of polyol derivatised silica gel is new to this field. The comparison and/or evaluation tries to be critical and to come to a conclusion for the choice of a recommended system.
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    Liquid chromatographic determination of dimethadione and trimethadione in human serum on octadecyl treated microporous glass columns (1987)
    Springer
    Chromatographia 23 (1987), S. 325-327 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Packings of octadecylated microporous glass ; Dimethadione and trimethadione in serum ; Pancreatic stones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The liquid chromatographic determination of trimethadione (TMO) and its methabolite, dimethadione (DMO) were studied by high-performance liquid chromatography (HPLC) on octadecyl-modified microporous glasses, prepared with toluene solution containing octadecyl-dimethylchlorosilane, using two types of microporous glass with various mean pore diameters and/or specific surface areas. Using acetonitrile-water mixtures as eluents, TMO and DMO in human serum were separated on the glasses studied, but with different degrees of resolution. In this present study, we report the development of a rapid and selective HPLC method for the simultaneous analysis of TMO and DMO in human serum.
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    Characterization of some commercial poly (styrene-divinylbenzene) copolymers for reversed-phase HPLC1 (1987)
    Springer
    Chromatographia 23 (1987), S. 341-349 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Cross-linked polystyrene ; Characterization of surfaces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The properties of the poly(styrene-divinylbenzene) copolymers PRP-1 and PLRP-S have been studied by infrared spectroscopy and chromatographic techniques. The following results were obtained: PRP-1 and PLRP-S are spectroscopically very similar. Their surfaces are chemically neither homogeneous nor stable during use. Retained nonpolar solutes should be eluted with a mobile phase containing tetrahydrofuran. Uncharged acids and anions can be chromatographed without difficulty. Cations of amines should be chromatographed only with a mobile phase of low pH. Uncharged amino-alcohols cannot be chromatographed without the addition of a competitor.
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    URL: http://dx.doi.org/10.1007/BF02316180
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    Preparation of silanized silica with high ligand density. The effect of silane structure (1987)
    Springer
    Chromatographia 23 (1987), S. 442-446 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chemically bonded phases ; Kinetics of silanization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A wide-pore silica for HPLC with a particle size of 7.5 μm, specific surface area of 360m2/g, pore diameter of 20 nm and pore volume of 2.1 cm3/g was silanized with n-octadecyldimethyl-chlorosilane (ODMCS), n-octadecyldimethylmetoxysilane (ODMMS) and n-octadecyldimethyl-dimethylaminosilane (ODMAS), in sealed glass ampoules. The ligand density obtained with an excess of ODMCS and ODMMS was found to be limited by reaction equilibrium; at low (〈50%) conversion of the surface silanols, the reaction displays pseudo-first-order kinetics. Silanization with ODMAS, which seems to be sterically controlled at higher conversions, yields a relatively high concentration of bonded octadecyl ligands (4.24μmol/m2).
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    HPLC on pentalfuoroanilinopropyl silica gel (1987)
    Springer
    Chromatographia 23 (1987), S. 684-685 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Pentafluoroanilinopropyl silica gel ; Donor-acceptor complexes ; Aromatic hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The preparation of a new pentafluoroanilino-phase for HPLC is described. The retention times (tr) of about twenty aromatic hydrocarbons have been determinated. It has been shown that the aromatics were eluted according to the number of rings. The influence of water content in the mobile phase is commented.
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    HPLC determination of thiol drugs in pharmaceutical formulations using ethacrynic acid as a precolumn ultraviolet derivatization reagent (1987)
    Springer
    Chromatographia 23 (1987), S. 680-683 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thiol drug analysis ; Derivatization by ethacrynic acid ; Pharmaceutical formulations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A high performance liquid chromatographic method has been developed for the determination of aliphatic thiol drugs, such as N-acetyl-L-cysteine, captopril and mercaptopropionylglycine in pharmaceutical formulations. The procedure involves a precolumn derivatization of the thiol drug with ethacrynic acid followed by reversedphase HPLC separation and UV detection. The conditions for a rapid and selective reaction of the thiols with ethacrynic acid have been investigated. The method proved to be suitable for a reliable and selective quality control of commercial dosage forms of the examined thiol drugs.
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    Trace analysis of sugars by HPLC and post-column derivatization (1987)
    Springer
    Chromatographia 23 (1987), S. 657-662 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Post-column derivatization ; Sugar analysis ; Wine characterization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A HPLC system with post-column derivatization for the quantitative analysis of sugars in complex matrices is described. As reagent a 0.2% solution of thymol in concentrated sulfuric acid has been used. The reaction is sensitive with reducing as well as non reducing sugars whereas sugar alcohols are discriminated. With this reagent and separation of sugars at high pH values with an anion exchange column it is possible to detect sugars in the ng range. Hence, it is possible to characterize wines not only by their fructose and glucose content but also by differences in the distribution of the other not fermentable sugars like trehalose, arabinose, galacturonic and glucuronic acid.
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    On-column catalysis of hydratization equilibria during liquid chromatographic analysis of acetaldehyde and formaldehyde (1987)
    Springer
    Chromatographia 23 (1987), S. 709-712 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Polymer-based support ; Aldehydes ; Fluorescence detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The aldehydes were separated by reversed phase chromatography on a polymer-based support. Acid catalysis on the column was needed to obtain sufficiently fast equilibrium between acetaldehyde and its hydrate. Deuterium labeled acetaldehyde (D3) yielded complete separation from the nonlabeled compound, probably due to a difference in hydratization. Fluorescent products were obtained by reaction between the aldehydes and a mixture of ammonia and dimedone (5.5-dimethyl-1.3-cyclohexanedione). The fluorescence was detected at 460 nm after excitation at 390 nm. A reaction time of 42 seconds at 90°C in a knitted teflon capillary produced detection limits of 0.5 and 1 ng for acetaldehyde and formeldehyde, respectively. A method for preparation of a stable reagent with low background fluorescence is described.
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    Effects of reducing agents on the determination of thiolic compounds in the presence of their disulfides using bimane pre-column derivatization (1987)
    Springer
    Chromatographia 23 (1987), S. 717-721 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thiols and disulfides ; Fluorescence derivatization ; Monobromobimane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The influence of reducing agents (sodium borohydride, tributylphosphine, dithioerythritol and dithiothreitol) on the conversion of disulfides into their parent thiols, with specific application to cysteine was investigated. Dithioerythritol and dithiothreitol were found to be most suitable for this reaction. A contact time of one hour at room temperature provided quantitative reduction as tested using cystine as a pure disulfide standard. A modified fluorescence labelling procedure with monobromobimane followed by reversed-phase HPLC allows quantitation of the parent thiol and the disulfide content when completing the labelling reaction with and without preliminary treatment with reducing agent. The effects of various bimane reducing agent ratios on the yield of the reaction are discussed. Precautions should be taken when dealing with complex matrices with respect to reagent concentrations and ratios.
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    Activated carbamate reagent as chiral derivatizing agent for liquid chromatographic optical resolution of enantiomeric amino compounds (1987)
    Springer
    Chromatographia 23 (1987), S. 899-902 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chrial separations ; Succinimido carbamate derivatives ; Propranolol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A chiral derivatization reagent having activated succinimido carbamate moieties were developed for the optical resolution of enantiomeric amines by high-performance liquid chromatography. Succinimido R-(+)- or S-(−)-1-phenylethyl and R-(+)- or S-(−)-1-(α-naphthyl)-ethyl carbamates were synthesized by the reaction of optically active phenylethyl and naphthylethyl amines with discuccinimido carbonate (DSC). These reagents reacted with both primary and secondary amine enantiomers such as amino acids and β-amino alcohols to give the corresponding diastereomeric urea derivatives. These diastereomers were efficiently separated by reversed-phase liquid chromatography and detected by their absorption or the fluorescence of the chromophores. The chiral derivatization procedure was applied to the separation and determination of enantiomeric propranolol in serum.
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    Optimization of the separation of polymethoxylated flavones in reversed phase liquid chromatography (1987)
    Springer
    Chromatographia 23 (1987), S. 15-20 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed phase operation ; Calculation of optimum solvent composition ; Polymethoxylated flavones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An optimization procedure for the chromatographic separation of polymethoxylated flavones is described. A polyhedron working volume is drawn from a truncated tetrahedron constructed from the four solvents selected. The response function is an n'th degree polynomial the coefficients of which are calculated through the least squares method by means of B=(X′X)−1X′Y in which X′X is the information matrix (X′X)−1 the variance covariance matrix. X is the matrix of the model (polynomial built from the selected experiments) and X′ the transposed matrix. Y is the quality of the chromatogram defined by the resolution of each pair of solutes. An exchange algorithm matrix yields the minimum number of runs necessary to obtain a correct B. Isoresponses curves are drawn by intersection of a cubic volume which includes the polyhedron to give a better insight. An optimal zone is then determined and provides the solvent composition. An optimized chromatogram of 8 methoxylated flavones demonstrates the application of the method.
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    Chromatographic determination of lactulose (1987)
    Springer
    Chromatographia 23 (1987), S. 132-136 
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    ISSN: 1612-1112
    Keywords: Gas chromatography ; Column liquid chromatography ; Thin-layer chromatography ; Analysis of lactulose in carbohydrate mixtures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Lactulose is a disaccharide with important implications in medicine, nutrition and dairy technology. It has to be determined usually as a minor component in complex matrices containing many other sugars. This paper describes the different chromatographic techniques (planar, liquid and gas chromatography) which have been proposed for the separation and quantification of lactulose in mixtures with other carbohydrates; the advantages of each technique are compared and some features where more research is necessary are outlined.
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    A study of the liquid chromatography of some fungicidally active arylsulphonohydrazides (1987)
    Springer
    Chromatographia 23 (1987), S. 328-330 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Arylsulphonohydrazides ; On-column hydrolysis ; Fungicides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A number of fungicidally active arylsulphonohydrazides are examined by normal- and reversed-phase liquid chromatography. Although good separations are achieved by reversed-phase LC, difficulties are encountered due to analyte hydrolysis. On the other hand, satisfactory analyses are possible by normal-phase LC particularly on modified silicas.
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    Rapid extraction of codeine and morphine in whole blood for HPLC analysis (1987)
    Springer
    Chromatographia 23 (1987), S. 377-378 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Solid phase extraction ; Codeine and morphine in blood
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A rapid and efficient procedure is described for the extraction and analysis of codeine and morphine in whole blood. Red blood cells were fragmented by sonication and the blood sample extracted by passing through a bonded silica column (Bond Elute®). The adsorbed drugs were washed and eluted followed by analysis by HPLC. Recoveries were between 95–100% at 5 ng/ml concentrations.
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    Liquid chromatographic analysis with electrochemical detection for metoclopramide in human plasma (1987)
    Springer
    Chromatographia 23 (1987), S. 651-652 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Metoclopramide ; Electrochemical detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple, reproducible liquid-chromatographic method for determination of metoclopramide anti-emetic and anti-spasmodic agent is described. Metoclopramide is extracted from alkalinized plasma into diethylether, then separated with a sperisorb CN column and measured through amperometric detection at +1,4 volt vs Ag/ AgCl. The average extraction recovery was 92%. Standard curves were linear and reproducible from 0.05 to 1.5 mg/ L. Within-day CV was better than 6%.
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    A solvent-free sampling method for airborne toluene diisocyanate (1987)
    Springer
    Chromatographia 23 (1987), S. 507-511 
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    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Toluene Diisocyanate in air ; Collector for air sampling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A useful method of sampling and measurement of toluene diisocyanate concentration in atmosphere is described. The sampler consists of glass-fibre filters impregnated with the reagent 1-(2-methoxyphenyl)piperazine1 so that the 2,4 and 2,6 isomers of TDI react to form urea derivatives which are analysed by high performance liquid chromatography in isocratic mode on cyan-amino and C18 bonded phases. A dynamic system was used to generate standard atmospheres of TDI and to validate the sampling method within the humidity range of 0% to 75%. A coated filter, a bubbling solution and an impregnated silica gel were compared as samplers requiring the piperazine reagent in performance experiments.
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    Morphological assortment in introduced Hawaiian passerines (1987)
    Springer
    Evolutionary ecology 1 (1987), S. 113-124 
    Details
    ISSN: 1573-8477
    Keywords: Competition ; morphological analysis ; community structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary To evaluate the role of competition in structuring communities, we conducted morphological analyses on the surviving species of passerine birds that were successfully introduced to the Hawaiian islands. Forty-nine species have been introduced a total of 111 times to five of the six main islands. There have been 33 extinctions. Our analyses were done at two separate organizational levels: all species introduced to an island; and all forest-dwelling species. If competition determines which species can coexist, and the intensity of competition is correlated with morphological similarity, then the surviving species should be overdispersed in morphological space. Further, sets of surviving species that coexist should be regularly positioned in morphological space. At the island-wide organizational level, the surviving species were neither overdispersed nor regularly positioned in morphological space. However, at the forest-wide level the surviving species were not only highly overdispersed, they were also regularly positioned when compared to randomly assembled communities.
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    Species assembly and the evolution of community structure (1987)
    Springer
    Evolutionary ecology 1 (1987), S. 201-213 
    Details
    ISSN: 1573-8477
    Keywords: Competition ; deterministic ; neutral model ; niche compression ; resource limitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In this paper I consider the evolutionary and ecological implications of an assembly rule which was derived empirically from studies on a heathland small-mammal community in south-eastern Australia. This rule has been tested successfully against 52 heathland small-mammal assemblages. Here it is shown to hold also for 80 forest assemblages of small mammals spanning a latitudinal range from 27°S to 43°S in south-eastern Australia. The observed forest communities are predicted by the rule and they deviate significantly from random assemblages. I suggest that the unique evolutionary history of the Australian fauna has made these patterns more apparent. The rule is simply stated as: ‘There is a much higher probability that each species entering a community will be drawn from a different functional group (genus or other taxonomically related group of species with similar diets) until each group is represented, before the cycle repeats’. A theoretical basis for the rule is proposed which extends the niche compression hypothesis to cover evolutionary time. Evolutionary constraints on adaptations for diet selection are greater than those operating on habitat selection. Successful tests in North America for the granivorous desert rodent guild and the mixed-forest insectivore guild support a wider application of this rule than the Australian communities from which it was derived. A speculative model is proposed in which the mechanisms involved in the operation of this rule shape the evolution of community structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02067551
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    Paper (German National Licenses)
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    Pattern recognition for earthquake detection by mental pictures (1987)
    Springer
    In:  Bull., Polar Proj. OP-O3A4, ASST'87, Berlin, Springer, vol. 81A, no. 16, pp. 347-350, (ISBN: 3-540-23712-7)
    Details
    Publication Date: 1987
    Keywords: Detectors ; Seismology ; Pattern recognition
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    BIBLIOGRAPHY SEISMOLOGY
  • 89
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    Automatische Detektion und Auswertung in Seismischen Netzen (1987)
    DGG
    In:  47. DGG-Tagung, Clausthal, DGG, vol. C 560, 183 pp., no. GL-TR-89-0143, pp. 235, (ISBN 3-933346-037)
    Details
    Publication Date: 1987
    Keywords: Data analysis / ~ processing ; Detectors ; ARR ; arc ; BUG ; Seismology ; Pattern recognition ; Seismic networks
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    BIBLIOGRAPHY SEISMOLOGY
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