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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 38 (2002), S. 0 
    ISSN: 1752-1688
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geographie
    Notizen: : Since 1989, the government of Pierce County, Washington, has prepared four watershed action plans. The watersheds cover almost 800,000 acres and include about 600,000 residents and diverse land uses, from the city of Tacoma to Mount Rainier National Park. The primary purpose of these plans was to address water quality impacts from nonpoint sources of pollution and to protect beneficial uses of water. Pierce County has experienced problems such as shellfish bed closures and the Federal Clean Water Act Section 303(d) listing of local water bodies as a result of declining water quality. Pierce County achieved improvements by engaging diverse groups of stakeholders in generating solutions to nonpoint sources of water pollution through our watershed planning process. Using participatory methods borrowed from private industry, Pierce County was able to reach consensus, build trust, maximize participation, facilitate learning, encourage creativity, develop partnerships, shorten time frames for the planning processes, and increase the level of commitment participants had to implementing the plans. As a result, the earliest plans have a high rate of voluntary implementation. This indicates that the process and methodology used to develop watershed plans has a significant, if not critical, impact on their success.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 13 (2001), S. 0 
    ISSN: 1460-9568
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: We have investigated the impact of neuromuscular activity on the expression of neurotrophins in the lumbar spinal cord region and innervating skeletal muscle of adult rats. Rats were exercised on a treadmill for 1 day or 5 consecutive days and euthanized at 0, 2 or 6 h after the last bout of exercise. By Day 1, there was no clear evidence of an increase in brain-derived neurotrophic factor (BDNF) mRNA in the spinal cord or the soleus muscle. By Day 5, there was a significant increase in BDNF mRNA in the spinal cord at 2 h post-training, and the soleus muscle showed a robust increase between 0 and 6 h post-training. Immunoassays showed significant increases in BDNF protein in the soleus muscle by training Day 5. Immunohistochemical analyses showed elevated BDNF levels in motoneuron cell bodies and axons in the ventral horn. Neurotrophin-3 (NT-3) mRNA was measured to determine whether selected neurotrophins respond with a selective pattern of induction to neuromuscular activity. In the spinal cord, there was a progressive post-training decrease in NT-3 mRNA following a single bout of training, while there was a significant increase in NT-3 mRNA at 2 h post-training by Day 5. The soleus muscle showed a progressive increase in NT-3 mRNA by Days 1 and 5 following training. These results show that neuromuscular activity has specific effects on the BDNF and NT-3 systems, and that repetitive exercise affects the magnitude and stability of these responses.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford UK : Blackwell Science Ltd.
    Weed research 42 (2002), S. 0 
    ISSN: 1365-3180
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: The development of integrated weed management strategies requires knowledge of mechanisms that influence compositional changes in weed flora. A 9-year study was initiated in 1988 at Delhi, Canada, on a loamy sand soil to evaluate the effect of tillage systems [conventional (CT) and no-till (NT)] and cover crops (only in NT) on weed density, species composition and associations, and crop yield in a winter wheat (Triticum aestivum L.)/bean/winter wheat rotation. Three bean types: soyabean (Glycine max L. Merr.), white bean (Phaseolus vulgaris L.) and kidney bean (P. vulgaris L.) were included. The NT system included variations: rye (Secale cereale L.) or maize (Zea mays L.) cover crop, volunteer wheat disked after harvest and wheat stubble. Data were collected in 1994, 1995 and 1996. Tillage systems, cover crops and crop type had differential effects on weed densities, species composition and associations. Weed densities were not affected by tillage or cover crops in wheat but, in the beans, densities were greater in the CT than in the NT systems. Various associations of weed species with tillage system, cover crop and crop type were observed. Crop yields were not affected by tillage type or cover crop, except that soyabean yields were highest in plots with cover crops.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 12 (2000), S. 1278-1295 
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A theoretical and numerical model is formulated to describe the instability and the long-time evolution of both gravity-driven and surface-shear-stress-driven thin coating films. A single evolution equation, of higher-order diffusive type, models the flow for either problem. It is derived using the lubrication approximation. For partially wetting systems, the effect of finite contact angle is incorporated in the equation using a particular disjoining pressure model. The base state, in each case, is a two-dimensional steadily propagating capillary front. Slight perturbations of the base state, applied along the front, initiate the fingering instability. Early-time results accurately reproduce the wavelengths of fastest growth and the corresponding eigenmodes as reported in published linear stability analyses. As time proceeds, depending on parameter values, various fingering patterns arise. For conditions of perfect wetting with the substrate downstream of the moving front covered with a thin precursor layer, predicted nonlinear finger evolution agrees well with published experiments. The ultimate pattern, in this case, is a steadily translating pattern of wedge-shaped fingers. Alternatively, for partially wetting systems that exhibit sufficiently large static contact angles, long straight-sided fingers or rivulets are formed. Finally, for larger contact angles, or at relatively low speeds, we predict that the flowing rivulets will become unstable and break up into strings of isolated droplets. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 13 (2001), S. 3089-3092 
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A functional is presented for the stored energy content, or potential energy, of a nonuniform distribution of surfactant on a liquid interface. This is the energy available to drive fluid motion using surface-tension-gradient forces. The functional is shown to be non-negative. An energy evolution equation is derived for the motion of a thin liquid film, whose shape evolves under the combined influence of surface tension, viscous, and surfactant effects. Numerical calculations show the time history of these global energy components. Results are relevant to the flow behavior of wetting agents, soap films, foams, and emulsions with possible applications in the industrial and biological worlds. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology ecology 32 (2000), S. 0 
    ISSN: 1574-6941
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Terrestrial sites contaminated with 2,4,6-trinitrotoluene (TNT) are a widespread and persistent problem and often contain non-vegetated areas with TNT concentrations well in excess of 1000 mg kg−1. In this study, we examined the effect of TNT on denitrification activity in field soils, and compared the sensitivity of denitrifying enzymes to TNT. DNA probes assessed the prevalence of nirS, nirK and nosZ (encoding cd1 or copper nitrite reductase and nitrous oxide reductase, respectively), denitrifying genotypes in the culturable and total microbial community. The nitrate (NaR), nitrite (NiR) and nitrous oxide (N2OR) reductase activities in field soil and in isolates were assessed by gas chromatography. The relative occurrence of the nirK, nirS or nosZ genotypes increased in the cultured community and in total uncultured community DNA as nitroaromatic concentrations increased. However, denitrifying activity decreased in response to increasing TNT concentrations, with an IC50 for NaR+NiR+nitric oxide reductase (NOR) of 400 mg TNT kg−1 soil and for N2OR of 26 mg TNT kg−1 soil. The denitrifying activity of four soil isolates also decreased in response to TNT, with N2OR activity being three times more sensitive to TNT than NaR+NiR+NOR activity. Interestingly, there were 118 times more nirK isolates than nirS isolates in uncontaminated soil but only 1.5 times more in soil containing 17 400 mg kg−1 TNT. The results from this study indicated that TNT reduced denitrification activity in field soils, and N2OR was much more sensitive to TNT than NaR+NiR+NOR.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1573-4870
    Schlagwort(e): Framework complex zirconium phosphates ; mechanochemical activation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract Cation- and anion-substituted zirconium phosphates of X kZr m (PO4) n−y Y composition, where X = Na+, La3+, NH4 +, Y = F−, WO4 2−, 1/3 〈 k 〈 2, 2 〈 m 〈 4, 3 〈 n 〈 6 were synthesized by the procedure, including mechanical activation of the starting salts mixture followed by annealing at 300–900°C. The interaction between components was studied by XRD, EXAFS, FT–IR, [31P-MAS] NMR. The possibility of synthesizing nonstoichiometric compounds is demonstrated and prospects for application of the mechanochemical method for synthesis of complex zirconium phosphates are outlined.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1433-075X
    Schlagwort(e): Key words Nanocomposites ; Framework zirconium phosphates ; Supported nanoparticles of WO3 ; MoO3 and Pt ; Catalysis of pentane and hexane isomerization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract  Nanocomposites based upon framework zirconium phosphates with supported WO3, MoO3 and Pt nanoparticles were synthesized via the incipient wetness impregnation of high-surface-area mesoporous phosphate samples with water solutions of corresponding salts followed by drying and calcination. The structure and surface properties of nanocomposites were studied by using combination of structural and spectral methods. Due to a strong interaction between supports and supported species, the structure of the latter differs considerably from that of the bulk phases. Surface acid centers typical for zirconium phosphates disappear suggesting their participation in bonding nanoparticles of promoters. Instead, new types of strong acid sites associated with tungsten oxide clusters emerge. The effect of these promoters on performance of zirconium phosphates in the reaction of pentane and hexane isomerization is considered.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Materials research innovations 4 (2000), S. 3-26 
    ISSN: 1433-075X
    Schlagwort(e): Keywords Perovskite ; Crystal-chemistry ; Tolerance factor ; Ferroics ; Electro-ceramics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract  Starting with the history of the fundamental science of the relation of structure to composition delineated completely by Goldschmidt, we use the perovskite structure to illustrate the enormous power of crystal chemistry-based intelligent synthesis in creating new materials. The perovskite structure is shown to be the single most versatile ceramic host. By appropriate changes in composition one can modify the most significant electroceramic dielectric (BaTiO3 and its relatives) phase in industry, into metallic conductors, superconductors or the highest pressure phases in the earth. After an historical introduction of the science, detailed treatment of the applications is confined to the most recent research on novel uses in piezoelectric, ferroelectric and related applications.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Materials research innovations 3 (2000), S. 183-184 
    ISSN: 1433-075X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Materialart: Digitale Medien
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