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  • Polymer and Materials Science  (16.437)
  • Fisheries
  • 1985-1989  (16.440)
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  • 1
    Digitale Medien
    Digitale Medien
    Regulated flushing in a gravel-bed river for channel habitat maintenance: A Trinity River fisheries case study (1987)
    Springer
    Environmental management 11 (1987), S. 479-493 
    Details
    ISSN: 1432-1009
    Schlagwort(e): Flushing ; Scouring ; Channel Maintenance ; Fisheries ; Trinity River
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract The operation of Trinity and Lewiston Dams on the Trinity River in northern California in the United States, combined with severe watershed erosion, has jeopardized the existence of prime salmonid fisheries. Extreme streamflow depletion and stream sedimentation below Lewiston have resulted in heavy accumulation of coarse sediment on riffle gravel and filling of streambed pools, causing the destruction of spawning, nursery, and overwintering habitat for prized chinook salmon (Salmo gairdnerii) and steelhead trout (Oncorhynchus tschawytscha). Proposals to restore and maintain the degraded habitat include controlled one-time remedial peak flows or annual maintenance peak flows designed to flush the spawning gravel and scour the banks, deltas, and pools. The criteria for effective channel restoration or maintenance by streambed flushing and scouring are examined here, as well as the mechanics involved. The liabilities of releasing mammoth scouring-flushing flows approximating the magnitude that preceded reservoir construction make this option unviable. The resulting damage to fish habitat established under the postproject streamflow regime, as well as damage to human settlements in the floodplain, would be unacceptable, as would the opportunity costs to hydroelectric and irrigation water users. The technical feasibility of annual maintenance flushing flows depends upon associated mechanical and structural measures, particularly instream maintenance dredging of deep pools and construction of a sediment control dam on a tributary where watershed erosion is extreme. The cost effectiveness of a sediment dam with a limited useful economic life, combined with perpetual maintenance dredging, is questionable.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01867656
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  • 2
    Digitale Medien
    Digitale Medien
    The need for conservation and management of Philippine coral reefs (1988)
    Springer
    Environmental biology of fishes 23 (1988), S. 141-154 
    Details
    ISSN: 1573-5133
    Schlagwort(e): Cyanide ; Diversity ; Development ; Ecology ; Environment ; Fisheries ; Pollution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis The biological diversity and productivity of Philippine coral reefs are threatened by siltation, destructive fishing methods, coral and shell collecting and overfishing. Destructive fishing includes: the widespread, illegal use of explosives; poisons such as sodium cyanide; muro-ami and kayakas fishing; and trawling. The recent decline in catch rates threatens the livelihood of 700 000 near-shore subsistence fishermen who catch 55% of the total landings. The new government under Corazon Aquino wishes to protect the marine environment through the creation of a viable marine conservation management plan, enforcement of existing laws and through cooperation between government, non-government and international agencies to provide education and research. The Department of Agriculture, which has the authority for fisheries, has designated the International Marinelife Alliance as the lead non-government agency involved with fund raising, net-training and finding alternatives to destructive fishing methods.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00000745
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  • 3
    Digitale Medien
    Digitale Medien
    Age, growth and reproductive biology of the silky shark, Carcharhinus falciformis, and the scalloped hammerhead, Sphyrna lewini, from the northwestern Gulf of Mexico (1987)
    Springer
    Environmental biology of fishes 19 (1987), S. 161-173 
    Details
    ISSN: 1573-5133
    Schlagwort(e): Chondrichthyes ; Elasmobranchs ; Fisheries ; Ageing methods ; Growth rates ; Gestation periods ; Maturity ; Vertebral bands ; Weight-length relationships ; Life histories
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis The silky shark, Carcharhinus falciformis, and scalloped hammerhead, Sphyrna lewini, represent 〉80% of the shark by-catch of the winter swordfish/tuna longline fishery of the northwestern Gulf of Mexico. This catch represents a potential supplemental fishery, yet little is known of the life histories of the two species. This report relates reproductive biology data to age and growth estimates for 135 C. falciformis and 78 S. lewini. Unlike other regional populations, C. falciformis in the Gulf of Mexico may have a seasonal 12 month gestation period. Males mature at 210–220 cm TL (6–7 yr); females at 〉225 cm TL (7–9 yr). Application of age at length data for combined sexes produced von Bertalanffy growth model parameter estimates of L∞ = 291 cm TL, K = 0.153, t0 = −2.2 yr. Adult male S. lewini outnumbered adult females in catches because of differences in the distributions of the sexually segregated population. Males mature at 180 cm TL (10 yr); females at 250 cm TL (15 yr). von Bertalanffy parameter estimates for combined sexes of this species were L∞ = 329 cm TL, K = 0.073, to = −2.2 yr.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00005346
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  • 4
    Digitale Medien
    Digitale Medien
    Copolymerization of cationic monomers with acrylamide in an aqueous solution (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 29-36 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The radical copolymerizations of commercially available cationic monomers (M1) with acrylamide (M2) have been investigated at pH 6.1 in aqueous solutions. The cationic groups in copolymers were analyzed by a colloid titration method and the reactivity ratios were determined by the Fineman-Ross method. The values of r1 and r2 were 1.71 and 0.25 for methacryloyloxyethyltrimethylammonium chloride—M2, 1.68 and 1.26 for N,N-dimethylaminoethylmethacrylate—M2, 1.13 and 0.57 for methacrylamidopropyltrimethylammonium chloride—M2, 1.10 and 0.47 for N,N-dimethylaminopropylmethacrylate—M2, 0.47 and 0.95 for N,N-dimethylaminopropylacrylamide—M2, 0.48 and 0.64 for acryloyloxyethyltrimethylammonium chloride-M2, and 0.58 and 6.7 for dimethyldiallylammonium chloride-M2 systems. The Alfrey-Price Q and e values were calculated and the linear relationship between log Q and ultraviolet absorption maxima of cationic monomers was found.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1986.080240103
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  • 5
    Digitale Medien
    Digitale Medien
    Functional polymers and sequential copolymers by phase-transfer catalysis. 16. Influence of sequence distribution on the mesomorphic properties of thermotropic copolyethers containing 4,4′-dihydroxybiphenyl (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 15-27 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Random and alternating thermotropic liquid-crystalline copolyethers have been synthesized from 4,4′-dihydroxybiphenyl and a 1/1 mol ratio of 1,5-dibromopentane and α,ω-dibromoalkanes by a two-phase (organic solvent-aqueous NaOH) phase-transfer-catalyzed polyetherification. Random copolyethers were prepared from α,ω-dibromoalkanes having six to twelve methylene units. Their phase behavior was compared with those of the perfectly alternating copolyethers containing five methylene units in one spacer and eight, nine, or eleven methylene units in the other, respectively. An odd-even dependence in thermal transitions has been observed in both oligomeric systems. In all cases, alternating copolyethers, even though comparatively lower in molecular weight, have given rise to higher melting and isotropization temperatures. Since the increase in the melting temperature is larger than the increase in the isotropization temperature, the thermal stability range of the mesophase has narrowed for alternating copolyethers with respect to their random copolyether counterparts.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1986.080240102
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  • 6
    Digitale Medien
    Digitale Medien
    Chemistry of alkenyl azlactones. VII. Preparation and properties of multiazlactones derived from mercaptan-functional compounds and oligomers (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 1-14 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of polymercaptans and 2-alkenyl azlactones has been further investigated, and several new multiazlactones which are liquids at room temperature have been prepared and characterized. Michael addition yielding the multiazlactones was found to take place slowly in the absence of and rapidly in the presence of acid catalysts. If basic impurities capable of forming mercaptide ion were present, however, the reaction underwent a substantially different course producing primarily ring-opened products. A source of these basic impurities was determined to be the method of preparation of the alkenyl azlactone itself. When the azlactone was prepared from its acyclic N-substituted aminoacid precursor by cyclodehydration by use of ethyl chloroformate and triethylamine, a small amount of triethylamine remained that dramatically altered the course of reaction. Nonbasic cyclodehydration agents such as dicyclohexylcarbodiimide were effective at eliminating this side reaction, as well as was the practice of adding excess acid to the reaction system to neutralize the basic impurities.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1986.080240101
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  • 7
    Digitale Medien
    Digitale Medien
    Carbazole substituted N-acylated linear polyethylenimines (PEI). synthesis and characterization of poly[N-(9-carbazolyl)acetylethylenimine] and poly[N-(2-(9-carbazolyl))propanoylethylenimine] (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 37-60 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The synthesis of carbazola substituted N-acylated polyethylenimines, namely, poly[N-(9-carbazolyl)acetylethylenimine] 20 and poly[N-(2-(9-carbazolyl))propanoylethylenimine] 21 by a grafting reaction onto PEI and isomerization polymerization of the carbazole substituted 2-oxazolines is reported. A complete acylation of amino groups in PEI by the 9-carbazolylacetyl groups was achieved by the p-nitrophenyl active ester method but PEI was only partially N-acylated by the 2-(9-carbazolyl)propanoyl groups under similar reaction conditions. The carbazole substituted 2-oxazolines, namely, 2-(9-carbazolyl)methyl-2-oxazoline 18 and (R,S)-2-[1-(9-carbazolyl)]ethyl-2-oxazoline 19, were prepared by a base induced cyclization of ß-chloroamides. The ring-opening isomerization polymerization of 18 and 19 in the molten state with a cationic initiator (dimethyl sulfate, methyl triflate, or ethylene glycol ditosylate) gave 20 and 21. Gel permeation chromatography of 20 and 21 obtained with different monomerto-initiator ratios gave evidence of a chain transfer reaction with the monomer. The polymers were characterized by elemental analyses, IR, and 1H-NMR spectroscopy.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1986.080240104
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  • 8
    Digitale Medien
    Digitale Medien
    Syntheses of stereoregular and optically active polyamides from active 4-chloro-1-benzotriazolyl diesters and diamines (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 75-85 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A new route to prepare optically active polyamides was established, based on the polycondensation of two new active diesters: the active diesters of 4-chloro-1 hydroxybenzotriazole, such as 1,1'-(terephthaloyldioxy)bis(4-chloro-benzotriazole), and 1,1'-(isophthaloyldioxy)bis(4-chlorobenzotriazole), with optically active isomers of 2,4-diaminopentane. Dipolar aprotic solvents such as N,N-dimethylformamide and dimethyl sulfoxide were used as reaction solvents. The solution polycondensation carried out in solution at room temperature afforded optically active polyamides. The aminolysis of the two active diesters was carried out as a model reaction study.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1986.080240106
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  • 9
    Digitale Medien
    Digitale Medien
    Permeation control of ionic fluorescent probes by ambient pH changes from nylon capsule membranes depending on their microstructuresPreliminary report: T. Seki and Y. Okahata, Macromolecules, 17, 1880 (1984). Functional Capsule Membranes 20. Part 19 of this series: Y. Okahata, K. Ariga and T. Seki, J. Chem. Soc., Chem. Commun., 920 (1985). (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 61-73 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Permeations of water-soluble, ionic fluorescent probes from a large, ultrathin nylon-2,12 capsule membrane were largely affected by the ambient pH of the outer medium; permeations of cationic and anionic probes were accelerated by a factor of 50-100 in the basic and acidic medium, respectively, relative to that in the neutral-pH region. The permeation of NaCl and nonionic fluorescent probes was hardly affected by the ambient pH. The nylon capsule membrane was elucidated to have an asymmetrical structure: the dense-thin inner layer and the porous-thick outer part. The pH-sensitive permeation could be explained due to the ionization of a small amount of residual end-groups (COOH and NH2) existing in the dense-thin inner layer of the nylon capsule membrane.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1986.080240105
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  • 10
    Digitale Medien
    Digitale Medien
    Cationic polymerization of p-methylstyrene initiated by acetyl perchlorate: An approach to living polymerization (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 87-96 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The cationic polymerization of p-methylstyrene initiated by acetyl perchlorate at -78°C led to long-lived (living-like) polymers with a narrow molecular weight distribution (M̄w/M̄n = 1.1-1.4) in methylene chloride containing a common ion salt (n-Bu4NClO4) or in a less polar solvent (CH2Cl2/toluene, 1/4v/v). Under these conditions, the number-average molecular weight (M̄n) of the polymers increased in proportion to monomer conversion and was regulated by the monomer-to-initiator ratio. When fresh feeds of the monomer were repeatedly added to a completely polymerized solution, the polymerization ensued at the same rate as before and the linear increase in M̄n with monomer conversion continued. The effects of solvent polarity and the common ion salt on the polymerization showed the suppression of the ionic dissociation of the propagating species, resulting in a “nondissociated species,” to be the key factor for the formation of the long-lived polymers.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1986.080240107
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