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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 20 (1995), S. 137-146 
    ISSN: 1432-0789
    Keywords: Larrea tridentata ; Simulated rainfall ; Precipitation exclusion ; Soil drying effects ; Analysis of covariance ; Chihuahan Desert ; Mineralization rate ; Field capacity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Irrigation and rain-out shelters were used to simulate precipitation patterns of wet and dry years in the northern Chihuahuan Desert. Irrigation provided approximately double the long-term average monthly precipitation. Rain was excluded during the wet season, July-October, to simulate a dry year. N net mineralization in laboratory incubations was undectable at calculated water potentials less than -1 MPa. Witb increasing moisture, mineralization gradually rose to the highest observed rates near field capacity. There was no mineralization maximum at moisture contents below field capacity. Irrigation significantly increased the water potential and rainfall exclusion reduced water potentials to less than-8 MPa. The general absence of important irrigation effects may have resulted from the high natural precipitation during the experiment or because irrigation inputs were insufficient to increase microbial activity during very dry periods. Precipitation exclusion reduced ion capture during the warm-wet season. After allowing precipitation inputs to resume, NH 4 + -N capture was increased in the cool-dry seasons of both 1987–1988 and 1988–1989. NH 4 + -N capture more than doubled that predicted from the overall covariance of moisture input and ion capture, suggesting increased availability of N. An unusually hot, dry period in May and June 1989 was followed by a threeto fourfold increase in the warm-wet season NO 3 − +NO2−N capture compared to 1988. These data suggest that short droughts of about 3 months in length (both simulated and natural) increased N availability relative to moisture availability.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 82 (1990), S. 18-25 
    ISSN: 1432-1939
    Keywords: Desert shrubs ; Larrea tridentata ; Nitrogen cycling ; Insects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We tested the hypothesis that herbivorous insects on desert shrubs contribute to short-term nitrogen cycling, and increase rates of nitrogen flux from nutrient rich plants. Creosotebush (Larrea tridentata) shrubs were treated with different combinations of fertilizer and water augmentations, resulting in different levels of foliage production and foliar nitrogen contents. Foliage arthropod populations, and nitrogen in canopy dry throughfall, wet throughfall and stemflow were measured to assess nitrogen flux rates relative to arthropod abundances on manipulated and unmanipulated shrubs over a one-month period during peak productivity. Numbers and biomass of foliage arthropods were significantly higher on fertilized shrubs. Sap-sucking phytophagous insects accounted for the greatest numbers of foliage arthropods, but leaf-chewing phytophagous insects represented the greatest biomass of foliage arthropods. Measured amounts of bulk frass (from leaf-chewing insects) were not significantly different among the various treatments. Amounts of nitrogen from dry and wet throughfall and stemflow were significantly greater under fertilized shrubs due to fine frass input from sap-sucking insects. Increased numbers and biomass of phytophagous insects on fertilized shrubs increased canopy to soil nitrogen flux due to increased levels of herbivory and excrement. Nitrogen excreted by foliage arthropods accounted for about 20% of the total one month canopy to soil nitrogen flux, while leaf litter accounted for about 80%.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1939
    Keywords: Larrea tridentata ; Leaf demography ; Nutrient resorption ; Nutrient-use efficiency ; Photosynthesis ; Water-use efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the Chihuahuan Desert of southern New Mexico, both water and nitrogen limit the primary productivity of Larrea tridentata, a xerophytic evergreen shrub. Net photosynthesis was positively correlated to leaf N, but only in plants that received supplemental water. Nutrient-use efficiency, defined as photosynthetic carbon gain per unit N invested in leaf tissue, declined with increasing leaf N. However, water-use efficiency, defined as the ratio of photosynthesis to transpiration, increased with increasing leaf N, and thus these two measures of resource-use efficiency were inversely correlated. Resorption efficiency was not significantly altered over the nutrient gradient, nor was it affected by irrigation treatments. Leaf longevity decreased significantly with fertilization although the absolute magnitude of this decrease was fairly small, in part due to a large background of insect-induced mortality. Age-specific gas exchange measurements support the hypothesis that leaf aging represents a redistribution of resources, rather than actual deterioration or declining resource-use efficiency.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 81 (1989), S. 166-175 
    ISSN: 1432-1939
    Keywords: Desert shrubs ; Larrea tridentata ; Nitrogen ; Plant-insect interactions ; Phytophagous insects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We conducted a field study to test the hypothesis that creosotebush (Larrea tridentata) shrubs growing in naturally nutrient-rich sites had better quality foliage and supported greater populations of foliage arthropods than shrubs growing in nutrient-poor sites. Nutrient-rich sites had significantly higher concentrations of soil nitrogen than nutrient-poor sites. Multivariate analysis of variance revealed significant differences between high nutrient and low nutrient shrubs based on a number of structural and chemical characteristics measured. High nutrient shrubs were larger, had denser foliage, greater foliage production, higher concentrations of foliar nitrogen and water, and lower concentrations of foliar resin than low nutrient shurbs. Numbers of foliage arthropods, particularly herbivores and predators, were significantly higher on high nutrient shrubs. Shrub characteristics and foliage arthropod abundances varied considerably from shrub to shrub. Shrub characteristics representing shrub size, foliage density, foliage growth, and foliar nitrogen and water concentrations were positively correlated with arthropod abundances. Foliar resin concentrations were negatively correlated with foliage arthropod abundances. The positive relationship between creosotebush productivity and foliage arthropods is contradictory to the tenet that physiologically stressed plants provide better quality foliage to insect herbivores.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 20 (1969), S. 578-583 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Cathodic corrosion of lead in the soilCathodic corrosion of lead in the soil can be expected in exceptional cases only. The corrosion found on a particular lead cable could be simulated in the laboratory. It could be confirmed, that  -  probably by decomposition of primary lead hydride  -  metallic lead is deposited below layers of Ca and Mg compounds already at potentials below -1,7 V. A special switching method was developed to account for breakthrough polarisation.
    Notes: Kathodische Korrosion von Blei im Boden ist grundsätzlich nur in Ausnahmefällen zu erwarten. Diese an einem Kabel gefundene Korrosion wurde im Laboratorium nachgebildet. Hierbei konnte bestätigt werden, daß unter Deckschichten aus Calcium- und Magnesiumverbindungen bei Potentialen schon unter -1,7 V metallisches, Blei abgeschieden wurde, wahrscheinlich durch Zersetzung von primär entstandenem Bleihydrid. Für derartige Untersuchungen wurde eine spezielle Schaltmethode entwickelt, bei welcher auch die Durchtrittspolarisation berücksichtigt wird.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 149 (1971), S. 295-301 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 50 (1978), S. 510-518 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Waste water purification at BASF, Ludwigshafen/Rh. The manifold problems encountered in the field of waste water treatment in the chemical industry are considered, together with the tasks involved, possible solutions, and costs incurred, for the example of BASF AG in Ludwigshafen. This example is particularly interesting because it shows how the waste water problems of a chemical factory that has been in existence for over a centurvey could be solved in the course of a ten-year plan. Twenty years after the inception of this plan, costs and success can now be quantified.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0308-0501
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 30 (1995), S. 165-176 
    ISSN: 0739-4462
    Keywords: Lepidoptera ; radioimmunoassay ; enzyme immunoassay ; equilibrium dialysis ; monoclonal antibody ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Numerous studies have demonstrated regulation of specific lepidopteran proteins by pharmacological doses of insect juvenile hormone (JH). In this study, topical application of a 1 pg dose of JH I to fourth stadium larvae of the black (bl) mutant strain of the tobacco hornworm, Manduca sexta, induced a 50% increase in the titer of hemolymph juvenile hormone binding protein (hJHBP). Radioimmunoassay confirmed that JH titers were lower in bl larvae than in wild-type larvae at the time of JH treatment. Enzyme immunoassay analysis of hJHBP titers demonstrated that regulation by JH I was dose-dependent at doses up to 10 pg and that the response was saturated above 100 pg. Western blotting and equilibrium dialysis confirmed these results and demonstrated that hJHBP from bl larvae had the same molecular mass and displayed the same affinity for JH I as hJHBP isolated from wild-type larvae. Time course studies showed that regulation was complex: 1 2 h after JH I treatment, hJHBP titers were twofold lower in treated than in control bl larvae, while 44 h after treatment they were twofold higher. JH I regulation of hJHBP titers in bl larvae was independent of changes in total hemolymph protein. © 1995 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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