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  • 1
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of organic chemistry 54 (1989), S. 1943-1948 
    ISSN: 1520-6904
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 22 (1989), S. 0 
    ISSN: 1365-2427
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: SUMMARY. 1. The distribution of macroinvertebrates in two chemically different rivers of Central Portugal (Soure and Alva) was analysed.2. In the Soure, a lowland, alkaline river (mean values for alkalinity, conductivity and pH, 101 mg I−1 CaCO3, 255 μS cm−1 and 7.8, respectively), a relatively high number of individuals and low diversity (mean H’= 2.27) was found. There was considerable temporal variation in the number of individuals present.3. In the Alva, a highland, acidic river (mean values for alkalinity, conductivity and pH. 4.8 mg 1−1 CaCO3, 22 μS cm−1 and 5.7, respectively), diversity was higher (mean H'=3.41). There were large temporal changes in the number of species present, but not in the number of individuals.4. Similarity indices and cluster analysis identified six site-types and seventeen groups of co-occurring taxa. Some of the taxonomic groups were characteristic of one or more sites, hut others had no strong association with a particular site. Although the rivers differed considerably in terms of physico-chemistry, communities in the upper sections of the two rivers were more similar to each other, than to other communities in the same river. The way the samples of both rivers were clustered seems to indicate that community structure was influenced by factors associated with (1) within river longitudinal variation (e.g. substrate grain size), (2) water chemistry, and (3) seasonal variations (e.g. temperature, flow).
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Tetrahedron Letters 31 (1990), S. 1365-1368 
    ISSN: 0040-4039
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1600-051X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Graça MA, Watts TLP. Wilson RF, Palmer RM: A randomized controlled trial of a 2% minocycline gel as an adjunct to non-surgical periodontal treatment, using a design with multiple matching criteria.Abstract Topical locally delivered minocycline is an adjunctive to non-surgical periodontal treatment, but there are few reported trials. Previous trials have reported differences between changes in probing depth in treatment and control groups, but no differences in probing attachment level. In the present study, 30 subjects were paired according to gender, age, ethnic group, smoking habits, and probing depths. Both groups received intensive oral hygiene education and root planing with local anaesthesia. Active or placebo gel was placed subgingivally at planed sites in each subject according to a double-blind protocol, immediately after instrumentation, and 2 and 4 weeks later. A periodontal examination was made with a constant force probe before instrumentation, and 6 and 12 weeks later. 2 subjects failed to complete the study, and their pairs were therefore not included in the analysis. Results were tested with analysis of covariance. Differences between groups in mean probing depth did not reach statistical significance at any visit (baseline: test (T)=5.93 mm, control (C)=5.74 mm; 6 weeks: T=3.53 mm, C = 3.63 mm; 12 weeks: T = 3.29 mm. C = 3.44 mm), but mean probing attachment levels were different (p〈0.05) at both reassessments (baseline: T=6.86 mm, C=6.83 mm; 6 weeks: T=4.93 mm, C=5.30 mm; 12 weeks T=4.91 mm, C=5.27 mm). There was also a difference in the number of sites with bleeding on deep probing at 12 weeks (p〈0.05). This trial showed that adjunctive minocycline gel provided a more advantageous outcome for nonsurgical periodontal treatment in terms of probing attachment level and bleeding on deep probing. This trial was a good example of experimental, as opposed to community, design, and used limited resources to show a clear result.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Oecologia 93 (1993), S. 139-144 
    ISSN: 1432-1939
    Schlagwort(e): Detritivores ; Trophic biology ; Gammarus pulex ; Asellus aquaticus ; Food choices ; Niche breadth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The importance of fungi in the trophic biology of the freshwater detritivores Gammarus pulex and Asellus aquaticus was investigated. Inspection of leaves used in feeding trials indicated that whereas A. aquaticus scrapes at the leaf surface, G. pulex bites through the leaf material. Both species discriminated between fungal mycelia, fungally colonized and uncolonized leaf material but, although A. aquaticus selectively consumed fungal mycelia, G. pulex fed preferentially on leaf material. Fungi appear to be an important food source for A. aquaticus and selection of food material was positively correlated with fungal biomass. In contrast, for G. pulex, fungi appear to be more important as modifiers of leaf material. However, no significant correlations were found between food preference and any of the leaf modifications measured.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Oecologia 96 (1993), S. 304-309 
    ISSN: 1432-1939
    Schlagwort(e): Food quality ; Growth ; Energy budgets ; Gammarus pulex ; Asellus aquaticus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An important component of the interaction between macroinvertebrates and leaf litter in streams in the extent to which consumers can differentiate between undecomposed and decomposing leaves. The detritivores Gammarus pulex and Asellus aquaticus fed preferentially on conditioned rather on unconditioned leaf material. Growth in A. aquaticus was significantly reduced when unconditioned leaves were provided, but in G. pulex no significant effect of conditioning on growth was observed. The capacity of G. pulex to tolerate reductions in food quality seems to be a consequence of a compensatory system in which respiration rates change to compensate for reductions in food quality. In this way a constant growth rate is maintained. Increases in ingestion rates to compensate for low quality food were not observed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 181 (1958), S. 182-183 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] It was Short* who first reported that methionine and S-methyl-L-cysteine reduced the nephrotoxicity of polymyxin A. Kimmerle and Gdsswald7 showed that N-acetylmethionine reduced the toxicity of streptomycin and briefly mentioned that the leucinate of the same antibiotic had no advantage over ...
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    ISSN: 1432-1793
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  The pathway for the flow of salt-marsh grass production into marsh food-webs is still not well defined. We compared the abilities of three marsh macroinvertebrates [salt marsh periwinkles, Littoraria irrorata (Say) (=Littorina irrorata), salt-marsh coffee-bean snails, Melampus bidentatus (Say); and a talitrid amphipod, Uhlorchestia spartinophila Bounsfield and Heard] to access standing-dead leaves of smooth cordgrass (Spartina alterniflora Loisel). The invertebrates were incubated with naturally-decaying leaves, and the rates of removal of organic matter and living fungal biomass (ergosterol) were measured. The impact of invertebrate activity upon fungal growth rates was measured as rates of fungal-membrane synthesis (incorporation of radioacetate into ergosterol). The removal rates of organic leaf biomass per mg individual biomass were highest for amphipods (700 μg mg−1 d−1) and lowest for periwinkles (90 μg mg−1 d−1), but the relatively large biomass of the snails made their removal rates per individual greater than those of amphipods. Net removal of ergosterol by all three invertebrates was 〉50% for yellow-brown (early-decay) leaf blades. For fully-brown (advanced-decay) blades, 〉50% removal of ergosterol was found only for periwinkles; exposure to coffee-bean snails and amphipods resulted in a net ergosterol reduction of ≤20%. The lower net reduction of living fungal biomass by coffee-bean snails and amphipods may have been due to fungal-growth stimulation (2.3-fold stimulation in coffee-bean snails and 1.5-fold stimulation in amphipods). Grazing by periwinkles did not stimulate fungal growth, possibly because of its high intensity. Grazing by these three salt-marsh shredders may affect marsh-grass shoot-decay in different ways. Periwinkles may abbreviate the period of fungal production, and incorporate the decaying material relatively quickly into snail biomass and fecal-pellet rain to the sediments. Coffee-bean snails and amphipods may enhance and prolong fungal production, along with the formation of fecal-pellet rain. All three invertebrates fed preferentially on leaf blades rather than leaf sheaths, and feeding rates of gastropods were higher during the night than during the day.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 386 (1998), S. 147-152 
    ISSN: 1573-5117
    Schlagwort(e): forest stream ; litterfall ; coarse benthic organic matter ; inputs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To evaluate the importance and fate of organic matter inputs in forested streams, we determined the litterfall inputs and the benthic coarse particulate organic matter (CPOM) in one headwater stream flowing through a mixed deciduous forest, during one year. Both vertical traps and the stream bottom were sampled monthly. The material collected was sorted into four main categories: leaves, fruits and flowers, twigs and debris. Litter production was 715 g m−2 y−1 and seasonal, with 73% of the annual total during October–December (autumn). Leaves comprised the largest litter component. Benthic organic matter was 1880 g m−2 y−1, and was also seasonal. Highest accumulation was attained in spring, and twigs and branches comprised the major component.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    ISSN: 1573-5117
    Schlagwort(e): reforestation ; litter dynamics ; streams ; aquatic macroinvertebrates ; Eucalyptus globulus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To test the hypothesis whether afforestation with Eucalyptus globulus affects litter dynamics in streams and the structure of macroinvertebrate aquatic communities, we compared streams flowing through eucalyptus and deciduous forests, paying attention to: (i) litterfall dynamics, (ii) accumulation of organic matter, (iii) processing rates of two dominant leaf species: eucalyptus and chestnut, and (iv) macroinvertebrate community structure. The amount of allochthonous inputs was similar in both vegetation types, but the seasonality of litter inputs differed between eucalyptus and natural deciduous forests. Eucalyptus forest streams accumulated more organic matter than deciduous forest streams. Decomposition of both eucalyptus and chestnut leaf litter was higher in streams flowing through deciduous forests. The eucalyptus forest soils were highly hydrophobic resulting in strong seasonal fluctuations in discharge. In autumn the communities of benthic macroinvertebrates of the two stream types were significantly different. Deciduous forest streams contained higher numbers of invertebrates and more taxa than eucalyptus forest streams. Mixed forest streams (streams flowing through eucalyptus forests but bordered by deciduous vegetation) were intermediate between the two other vegetation types in all studied characteristics (accumulation of benthic organic matter, density and diversity of aquatic invertebrates). These results suggest that monocultures of eucalyptus affect low order stream communities. However, the impact may be attenuated if riparian corridors of original vegetation are kept in plantation forestry.
    Materialart: Digitale Medien
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