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  • 1985-1989  (38)
  • 1980-1984
  • 1870-1879
  • 1987  (38)
  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 28 (1987), S. 836-839 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: Addition theorems for spherical wave solutions of the vector Helmholtz equation are discussed. The theorems allow one to expand a vector spherical wave about a given origin into spherical waves about a shifted origin. A simplified derivation of the results obtained earlier by Cruzan [O. R. Cruzan, Q. Appl. Math. 20, 33 (1962)] is presented.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 121-123 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the largest peak-to-valley current (PVC) ratios to date from AlGaAs/GaAs double barrier (either alloy barrier or superlattice barrier) diodes. PVC ratios as high as 3.6 and 21.7 were obtained from an AlAs/GaAs superlattice barrier structure at 300 and 77 K, respectively. In an alloy barrier structure with x=0.42 (x=0.3), PVC ratios of 3.9 (2.2) and 14.3 (7.0) were observed at 300 and 77 K, respectively. We attribute these excellent results to a "two-step'' spacer layer incorporated in the devices studied which facilitated the growth of high material quality.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 23 (1987), S. 0 
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : The impact of urbanization on stream insect communities was determined by sampling 22 sites in northern Virginia representing a range of human population densities. Watershed development had little effect on the total insect numbers (no./m2), but shifted the taxonomic composition markedly. Relative abundance of Diptera (mainly chironomids) increased at more highly urbanized sites, while most other insect orders including Ephemeroptera (mayflies), Coleoptera (bettles), Megaloptera (dobsonflies), and Plecoptera (stone-flies) decreased. Trichoptera (caddisfiles) exhibited a variable response. Genus diversity and richness (number of genera) were significantly higher in less urbanized streams. Two genera of chironomids were positively correlated with increased urbanization, while 14 other genera (scattered through several orders) were negatively related to human population density. Principal components analysis demonstrated a gradient from more urbanized to less urbanized stations based on generic and order level biological data. Results of this study indicate that watershed urbanization has a major impact on benthic insect communities even in the absence of point source discharges.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Anaesthesia 42 (1987), S. 0 
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The case is described of a patient who underwent artificial ventilation in an intensive therapy unit and received an infusion of alcuronium 10 mg/hour for more than 4 days, in the presence of significant renal (and later, some degree of hepatic) impairment. Prolonged and profound neuromuscular block persisted despite haemodialysis (5 hours on each of 3 days) followed by 72 hours of continuous haemofiltration; it appeared to resolve only after plasma exchange (4 litres). The total period of persistent block, for 9 days after the infusion had been stopped, is thought to be the longest period ever reported after administration of alcuronium. Neuromuscular block was monitored throughout this period using the train-of-four twitch technique. The potentiating effects of concurrent aminoglycoside therapy and hepatic dysfunction on the degree of paralysis are discussed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Anaesthesia 42 (1987), S. 0 
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 17 (1987), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. 1. The effect of ionic strength on the configuration of aquatic humic substances was studied by gel filtration and dialysis of water from small. Finnish forest lakes of varying colour.2. Sephadex gel filtration of water from the most humic lake gave similar elution profiles of UV absorbance and dissolved organic carbon (DOC). Gel filtration of unconcentrated samples from all three lakes under natural conditions of ionic strength (I = 1.7 × 10−4) and pH (5.5–6.0) gave similar fractionation of humic substances, despite their widely differing colour (30–350 mg Pt l−1) and DOC (5–25mg C l−1).3. Increasing the ionic strength by two orders of magnitude caused considerable retardation on the Sephadex columns of the humic substances, suggesting a decrease in their molecular size and/or shape.4. Dialysis experiments strongly indicated that ionic strength-induced changes in the configuration of the aquatic humic substances are indeed real. Hence it is probable that the elution behaviour of aquatic humic substances on Sephadex gels has previously been wrongly attributed to ionic strength-dependent interactions between the gel and the humic substances.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 109 (1987), S. 1275-1278 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 109 (1987), S. 3169-3171 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 10 (1987), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract. The interrelationships of leaf diffusive conductance, tap root cell turgor pressure and the diameter of the tap root of sugarbeet were studied. The study was conducted on well-watered plants growing in pots under artificial light in the glasshouse. In a typical experiment, on illumination (400 μmol m−2 s−1) leaf conductance increased from 0.6 to 7.4 mm s−1. Cell turgor pressure in the tap root decreased from 0.8 MPa to 0.45 MPa and the root diameter (9.0 cm) contracted by 145μm. Removal of light resulted in the reversal of each of the above parameters to their previous values. Quantitively similar results were obtained when sugar beet plants were uprooted and the response of each of the parameters was measured. The sequence of events however was different. On stimulation by light, changes in leaf diffusive conductance preceded the turgor and root diameter changes (which were simultaneous) by some 15–20min. In contrast, on uprooting the simultaneous changes in root turgor pressure and diameter preceded the changes in leaf conductance. The lag times between changes in diffusive conductance and turgor pressure in the root were between 20 and 30 min.Tap root turgor pressure and diameter correlated strongly and permitted the calculation of an apparent whole root volumetric elastic modules (55–63 MPa). The small changes in tissue volume relative to the transpiration rate suggest that the tap root is not a significant source of transpirational water during the day.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    International journal of food science & technology 22 (1987), S. 0 
    ISSN: 1365-2621
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fifty-two ham samples were assessed by a trained panel of ten assessors for appearance, texture and flavour using twenty-two descriptive and three hedonic scales. Generalized Procrustes analysis was used to reveal the spatial configuration of the samples, taking account of differences between individual assessors. The first principal axis accounted for 33% of the overall variation and was related to ‘plastic’ and gelatinous appearance, and firm texture. The second principle axis accounted for 17% of the variation and was related to rubbery, firm, plastic and cohesive texture descriptors, and plastic appearance. The third principal axis accounted for 10% of the variation and was related to the appearance and flavour of the product with dominant colour, fatness and saltiness prominent. The mechanical properties were characterized as shear strength, tensile strength and by a model of visco-elasticity. Firmness increased with shear strength and the gelatinous, plastic appearance was related to the amount of bound water. Cohesiveness and rubberiness increased with ultimate tensile strength and total water content. The equilibrium modulus and principal relaxation times characterized the first two principal axes and gave a good indication of the texture of the products. Ninety-one per cent of the variation in the combined overall hedonic scores was accounted for by the first principal axis—the preferred ham having a firmer, meaty texture. Shear strength and bound moisture were the two best single mechanical indices of this overall liking.
    Type of Medium: Electronic Resource
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