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  • 1
    Electronic Resource
    Electronic Resource
    Reproduction in an aggregating grouper, the red hind,epinephelus guttatus (1994)
    Springer
    Environmental biology of fishes 41 (1994), S. 269-286 
    Details
    ISSN: 1573-5133
    Keywords: Spawning ; Serranidae ; Pisces ; Puerto Rico ; Protogyny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis We examined the reproductive pattern of an aggregating grouper, the red hind,Epinephelus guttatus, in Puerto Rico. Macroscopic and histological examination of gonads confirmed that, although mature, ripe ovaries are found over a three-month period, spawning activity is limited to about 2 weeks each year. Females are determinate spawners and individuals are able to spawn more than once during the course of the annual spawning season. The red hind is protogynous and 50% maturity is attained at 215 mm fork length. In western Puerto Rico, spawning occurs in aggregations at several sites within loosely defined areas located towards the edge of the insular platform. Sex ratios of individuals taken by hook and line at one of the aggregation areas over a consecutive six-year period, suggest considerable intra- and inter-annual variation most likely attributable to a combination of differential ingress and egress by males and females during the course of an aggregation and to fluctuations in recruitment, differential mortality by sex and sex change among years. A comparative assessment of the reproductive patterns of seven western AtlanticEpinephelus spp. suggests that aggregation-spawning is associated with medium- to large-sized groupers, while smaller groupers do not aggregate. Mating systems vary among congeners in association with trends in male-female size dimorphism, sexual pattern and sperm competition. The short-term, localized, nature of spawning aggregations renders species with this reproductive mode particularly vulnerable to fishing pressure at spawning sites. Aggregating species, therefore, may require special management consideration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02197849
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  • 2
    Electronic Resource
    Electronic Resource
    Reproduction in an aggregating grouper, the red hind,epinephelus guttatus (1994)
    Springer
    Environmental biology of fishes 41 (1994), S. 269-286 
    Details
    ISSN: 1573-5133
    Keywords: Spawning ; Serranidae ; Pisces ; Puerto Rico ; Protogyny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis We examined the reproductive pattern of an aggregating grouper, the red hind,Epinephelus guttatus, in Puerto Rico. Macroscopic and histological examination of gonads confirmed that, although mature, ripe ovaries are found over a three-month period, spawning activity is limited to about 2 weeks each year. Females are determinate spawners and individuals are able to spawn more than once during the course of the annual spawning season. The red hind is protogynous and 50% maturity is attained at 215 mm fork length. In western Puerto Rico, spawning occurs in aggregations at several sites within loosely defined areas located towards the edge of the insular platform. Sex ratios of individuals taken by hook and line at one of the aggregation areas over a consecutive six-year period, suggest considerable intra- and inter-annual variation most likely attributable to a combination of differential ingress and egress by males and females during the course of an aggregation and to fluctuations in recruitment, differential mortality by sex and sex change among years. A comparative assessment of the reproductive patterns of seven western AtlanticEpinephelus spp. suggests that aggregation-spawning is associated with medium- to large-sized groupers, while smaller groupers do not aggregate. Mating systems vary among congeners in association with trends in male-female size dimorphism, sexual pattern and sperm competition. The short-term, localized, nature of spawning aggregations renders species with this reproductive mode particularly vulnerable to fishing pressure at spawning sites. Aggregating species, therefore, may require special management consideration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023817
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  • 3
    Electronic Resource
    Electronic Resource
    Preparation of [5 + 6]-, [6 + 6]-, and [6 + 7]-Bicyclic Guanidines from C,C'-Bis(iminophosphoranes) (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 1641-1652 
    Details
    ISSN: 0009-2940
    Keywords: Bis(iminophosphoranes) ; Guanidines, bicyclic ; Aza Wittig reaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A one-pot synthesis of [5 + 6]-, [6 + 6]-, and [6 + 7]-rigid bicyclic guanidines (6, 8, 19, 21, 23) based on a bis(iminophosphorane)-mediated annulation strategy is reported. The crystal and molecular structure of the parent [5 + 6]-bicyclic guanidine 8 has been established by X-ray diffraction. The crystallographically independent molecule forms dimers through a centre of symmetry by N-H-N hydrogen bonds. The molecule, and therefore the dimer, is statistically disordered in a 65/35 ratio. A statistical study of N-H-N hydrogen bonds of this kind of dimers has been carried out by using the Cambridge Structural Database.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270916
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  • 4
    Electronic Resource
    Electronic Resource
    Orientation of propylene units in polypropylene and ethylene/propylene copolymers (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 1121-1128 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Äthylen-Propylen Copolymere, die mit spezifisch syndiotaktischen Katalysatoren dargestellt werden, enthalten sowohl Kopf-Schwanz als auch Schwanz-Kopf orientierte Propyleneinheiten. Daher ist diese Copolymerisation eigentlich eine Terpolymerisation und die einfache Propylenpolymerisation eine binäre Copolymerisation.Die sich daraus für die Kinetik der Polymerisation und Copolymerisation ergebenden Konsequenzen werden untersucht.
    Notes: Ethylene-propylene copolymers prepared with syndiotactic specific catalysts contain both head-to-tail and tail-to-head oriented propylene units. Consequently, this copolymerization is, actually, a terpolymerization, and the propylene polymerization is a binary copolymerization.The consequences of this fact on the kinetics of polymerization and copolymerization are considered.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.021760419
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  • 5
    Electronic Resource
    Electronic Resource
    Properties of solution grown crystals of aliphatic polyesters with variable amount of double bonds along the chain (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 1023-1035 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In order to elucidate the relations between morphological habits, thermal behaviour and chemical structure of polymers, aliphatic polyesters with variable amount of trans-double bonds along the backbone chain were crystallized from dilute solutions in 1-propanol and 1-butanol. The crystals were studied with electron microscopy, differential scanning calorimetry, and wide angle X-ray diffraction. The morphology of solution grown single crystals and some thermodynamic quantities such as the equilibrium dissolution and melting temperature and the enthalpy and entropy of fusion are influenced by the percentage of unsaturated comonomer. The thermal behaviour and the X-ray diffraction of these crystals suggest that saturated and unsaturated repeating units are able to cocrystallize.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1979.021800419
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  • 6
    Electronic Resource
    Electronic Resource
    Glass transition temperature of linear saturated and unsaturated polyesters (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 1037-1040 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In the present paper we have investigated the role that the presence of trans double bonds plays on the glass transition temperature of linear polyesters. Experimental data indicate that the glass transition temperature is increased by an increase of the unsaturation concentration. The effect is not drastic but it is well detectable. This result is discussed taking into account the chain microstructure and the bulk structure effects.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1979.021800420
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  • 7
    Electronic Resource
    Electronic Resource
    Melting and crystallization behaviour of random copolymers from adipic acid, trans-3-hexenedioic acid and 1,16-hexadecanediol (1980)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 1339-1348 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Copolyesters derived from adipic acid, trans-3-hexenedioic acid and 1,16-hexadecanediol were prepared and investigated by means of X-ray diffraction and DSC techniques. From the X-ray results an isomorphous replacement of the saturated and unsaturated diacid units has been suggested. The equilibrium melting temperature Tm0 and the heat of fusion ΔHf were slightly dependent on the copolyester composition. The crystallization process was analyzed by means of Hoffman's kinetic crystallization theory for a lamellar type crystal growth. The values of the free energy of formation of a nucleus of critical dimensions φ* and the free energy of folding σe were found to decrease regularly with increasing amount of double bonds, varying from 110 to 83 kJ/mol for Δφ* and from 171 to 127 erg/cm2 for σe. This effect has been interpreted on the basis of an increase of chain flexibility owing to the presence of the trans double bonds.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1980.021810614
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  • 8
    Electronic Resource
    Electronic Resource
    Dynamic mechanical behaviour of linear polyamides with different degree of unsaturation in the chain (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 201-207 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dynamic mechanical behaviour of polyamide systems containing different degrees of unsaturation was analyzed. The results do not show any simple relation between unsaturation and mechanical response. Particular attention was given to the α-transition, that is a glass transition, and experimental data suggest that the generally accepted mechanism for this transition requires a more extensive study.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021790120
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  • 9
    Electronic Resource
    Electronic Resource
    Acid and base functionalization of ethylene-propylene rubbers, 1. Grafting of tertiary amino groups and “interpolymer” network formation (1987)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 951-960 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Base functionalization of saturated ethylene-propylene rubbers (EPR) was performed either by means of the radical grafting of 2-(dimethylamino)ethyl methacrylate onto EPR or by the reaction of a succinic anhydride grafted EPR with N,N-dimethylethylenediamine. Differences in the structure of the grafted molecules and in their thermal stability are also reported. An investigation is made on the reactivity of EPR having tertiary amino pendant groups toward acid functionalized EPR leading to gelation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1987.021880502
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  • 10
    Electronic Resource
    Electronic Resource
    Dynamic mechanical relaxations in a copolyterephthalate based on ethylene glycol and 1,4-cyclohexanedimethanol (1988)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 189 (1988), S. 1207-1217 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dynamic mechanical relaxations of poly(ethylene terephthalate) (PET), poly(1,4-cyclo-hexylenedimethylene terephthalate) (PCHDMT), and a copolymer of them (COP) were measured in the temperature range from -150 to 150°C by use of a dynamic viscoelastometer. The viscoelastic relaxations of COP are studied and compared with those of PET and PCHDMT. The anisotropy of the viscoelastic properties of stretched COP samples was also studied in order to distinguish between main and secondary relaxations.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1988.021890522
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