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  • 1
    ISSN: 1573-1561
    Keywords: Artificial diet ; herbivory ; nitrogen ; Lymantria dispar ; Lepidoptera ; Lymantriidae ; monoterpenes ; nutritional ecology ; phenolics ; Pseudotsuga menziesii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two experiments were conducted to examine the influence of foliar nitrogen, terpenes, and phenolics of Douglas-fir on the development of gypsy moth larvae. In the first experiment, foliar concentrations of nitrogen and allelochemicals were manipulated by fertilizing 3-year-old potted seedlings with 0 or 200 ppm nitrogen. Concentrations of foliar nitrogen (0.33–2.38%) were negatively correlated with the phenolics (15.8–24.4 mg/g). Sixth-instar larvae previously reared on current-year Douglas-fir needles were allowed to feed on these seedlings. Pupal weights (312.8–995.6 mg) were positively correlated with levels of foliar nitrogen, negatively correlated with amounts of foliar phenolics, and uncorrelated with terpene concentrations. In the second experiment, terpene and phenolic extracts from Douglas-fir foliage were incorporated at natural levels into artificial diets with high and low levels of protein nitrogen. Neonate larvae grew faster and were larger on the high nitrogen control diet (4.1–4.5%), however, fourth instars performed better on the control diet with low nitrogen levels (2.5–2.7%). Foliar terpenes incorporated into diet had little effect on neonate fitness, but may induce subtle physiological changes in later instar larvae. Phenolics, alone or in combination with terpenes, excessively suppressed growth and survival, with no individuals living through the fourth instar, regardless of the nitrogen level. Incorporating foliar phenolic extracts into artificial diet caused unnatural levels of toxicity and failed to clarify the effects of Douglas-fir phenolics on gypsy moth fitness. Foliar nitrogen is a key factor influencing gypsy moth development on Douglas fir, but may be mitigated to some degree by phenolics.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-1561
    Keywords: Aggregation ; pheromone ; elm ; mark-release ; multilure ; Coleoptera ; Scolytidae ; Scolytus multistriatus ; trap-out ; Ulmus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two experiments were conducted to investigate the use of a pheromone-based trap-out technique for suppressing populations ofScolytus multistriatus. In the first experiment, elm bolts containing the immature stages ofS. multistriatus were placed in an isolated community that contained elm trees, but which was essentially devoid of a resident beetle population. The infested bolts produced a total of 46,485 adult beetles of which 20% were recovered on traps baited with synthetic pheromone. In the second experiment beetles were released in a desert valley containing no resident elms or beetles. Only 1% of 20,000 released beetles were recaptured on traps erected on vertical cardboard cylinders and on elm logs. These rates of recapture are related to the attraction of beetles to naturally occurring brood sources versus pheromone-baited traps.
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  • 3
    ISSN: 1573-1561
    Keywords: Douglas-fir ; Pseudotsuga menziesii ; gypsy moth ; Lymantria dispar ; Lepidoptera ; Lymantriidae ; insect-host plant relations ; phenolics ; terpenes ; white alder ; Alnus rhombifolia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Individual families of gypsy moth collected from a single population exhibited different degrees of fitness when fed diets of white alder, a suitable broadleaf host, and Douglas-fir, an unsuitable conifer host. Members of families on diets of Douglas-fir had significantly lower survival, longer larval periods, lower pupal weights, and shorter pupal periods than members of the same families fed alder. Foliar nutritional quality, including nitrogen level and allelochemical composition (terpenes and phenols), was considered the key factor responsible for these differences. Growth parameters differed significantly for families within diet treatments, indicating that the genetic resources of a family did affect performance somewhat. The influence of a family's genetic resources on larval survival was most notable when larvae were under the greatest nutritional stress.
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  • 4
    ISSN: 1573-1561
    Keywords: Coleoptera ; Scolytidae ; bark beetle ; Dendrocionus ; Ips ; pheromone ; colonization ; attraction ; inhibition ; behavioral interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Chemically mediated behavioral interactions among four species of Scolytidae cohabitingPinus taeda in east Texas appear to be significant in delineating breeding areas within trees and in influencing the sequence of colonization.Dendroctonus frontalis usually arrived first and was not attracted to logs occupied by any of the threeIps species (I. avulsus, I. calligraphus, andI. grandicollis). The response ofI. avulsus to conspecific males was enhanced by the simultaneous presence of actively boring maleI. grandicollis. The response ofIps calligraphus was inhibited in areas whereI. avulsus was also present, but, in turn,I. calligraphus inhibited the response ofI. grandicollis and attractedI. avulsus. Ips grandicollis was strongly inhibited by the simultaneous presence of femaleD. frontalis or maleI. calligraphus, and in turn, maleI. grandicollis inhibitedD. frontalis. The result of this highly interactive olfactory system is that host trees are colonized very rapidly and that, in the process, disadvantageous reproductive interactions are minimized.
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  • 5
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 18 (1978), S. 372-377 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The viscosity-shear rate functions for polysulfone (PSF) condensates ranging from 0.4RV to 0.95RV were determined using capillary rheometry, The most probable distribution of molecular weights of these resins allowed facile comparison with the polydisperse Bueche theory for viscosity, The agreement in shape of the viscosity function with theory was good but the data were displaced by a factor of 3 to 4 to higher reduced shear rate, a fairly common occurrence for melts. The high absolute value of PSF viscosity was explained with existing empirical correlations as a combination of low critical molecular weight and strong intermolecular interactions. The temperature dependence of viscosity was found to be close to that for polystyrene in the temperature range, Tg + 90 to Tg + 190°C. The die swell, end corrections, and melt fracture characteristics were also determined. The latter was found to occur at a constant wall shear stress of about 6 × 106 dynes/cm2 while the die swell and end corrections were found to be small.
    Additional Material: 10 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 97-103 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Results are presented from a detailed study of the formation of strong relativistic shocks from simple waves in a fluid obeying the Synge equation of state for a relativistic particle gas. Subsequent damping is also followed, and the results are compared with those obtained previously for a model radiation-dominated gas. In this paper, planar flow is considered and self-gravity of the waves is neglected.
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  • 7
    ISSN: 1432-2242
    Keywords: Narrow sense heritability ; Analysis of covariance ; Standardized heritability estimates ; Genotype x environment interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The implications of bias due to previous inbreeding of parents and genotype x environmental interaction on narrow sense heritability (h2) estimates by parent-offspring regression are enumerated. To remove the bias caused by genotype x environment interaction, an analysis of covariance model could be used. In special cases, where phenotypic expression is a result of two organisms interacting, such as in symbiotic N2 fixation, an analysis of covariance model with a test of heterogeneity of slopes is recommended. When host genotype x strain interactions are significant, separate heritability estimates for each strain are suggested to take advantage of genotype x strain interaction, which may be a major factor contributing to the expression of N2 fixation traits.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-2242
    Keywords: RFLP ; Tomato ; Probe source ; Probe length ; Restriction enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Since the construction and use of RFLP genetic maps depends on the ability of cloned sequences to detect polymorphism, we have attempted to determine conditions under which maximum levels of polymorphism can be detected. Forty cloned nuclear sequences from three different libraries (cDNA, EcoRI genomic, and Pstl genomic) were hybridized to total DNA from 149 plants representing eight species of the tomato genus Lycopersicon. Five different restriction enzymes were employed in this study. We examined the relationship between polymorphism (number of restriction patterns) and clone size, restriction enzyme, size of hybridizing restriction fragments, and clone source (library). We found no relationship between clone size (ranging from 0.4 to 5.3 kb) and polymorphism. There was a strong positive relationship (r 2 = 0.79) between polymorphism and the average size of the fragments produced by each restriction enzyme. cDNA clones hybridized to larger fragments compared to genomic clones. cDNAs also detected significantly more polymorphism (approximately 25% more) than genomic clones — possibly indicating high levels of sequence variability in introns and/or areas flanking coding regions.
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  • 9
    ISSN: 1432-2242
    Keywords: Lycopersicon ; Phylogeny ; RFLP ; Genetic variation ; Breeding system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Forty single-copy, nuclear probes of known chromosomal position were used to examine restriction fragment length polymorphism in the tomato genus Lycopersion. The probes were from three libraries: one cDNA, and two genomic libraries ⦓ne genomic made with EcoRI and the other with PstI. Total DNA from 156 plants representing eight species was cut with five different restriction enzymes and scored in 198 probe-enzyme combinations. Genetic distances between accessions (populations) and species were calculated from the resultant restriction patterns and proportion of shared bands. Accessions belonging to the same species largely clustered together, confirming their current classification. However, one mountain accession, classified as L. peruvianum var. humifusum (LA2150), was sufficiently distinct from the other accessions of L. peruvianum that it may qualify as a separate species L. esculentum and L. pimpinellifolium were the least clearly differentiated, possibly reflecting introgressive hybridization, known to have been promoted by man in recent history. Dendrograms constructed from cDNA versus genomic clones were nearly identical in their general grouping of species. The dendrograms revealed two major dichotomies in the genus: one corresponding to mating behavior [self-compatible (SC) versus self-incompatible (SI) species] and the other corresponding to fruit color (red versus green-fruited species). The ratio of withinversus between-accession diversity was much lower for SC species, indicating that most of the diversity within these species exists between populations, rather than within populations. Overall, the amount of genetic variation in the SI species far exceeded that found in SC species. This result is exemplified by the fact that more genetic variation could be found within a single accession of one of the SI species (e.g., L. peruvianum) than among all accessions tested of any one of the SC species (e.g., L. esculentum or L. pimpinellifolium). Results from this study are discussed in relationship to germ plasm collection/utilization and with regard to the use of RFLPs in tomato breeding and genetics.
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  • 10
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 19 (1979), S. 1098-1103 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Neck-in and maximum stress were studied in a tape-drawing experiment using a 3.5 MI low density polyethylene at 300°C. The conditions of the experiment were designed to reproduce closely those found in extrusion coating lines. The maximum stress was found to increase roughly with the 1.6 power of the drawdown ratio and the 1.0 power of the extrusion speed over a stress range of 4 × 103 to 5 × 105 Pa produced by drawdown ratios ranging from 2 to 22 and extrusion speeds of 2.3 to 6.1 cm s-1. The neck-in decreased weakly with drawdown ratio at low extrusion speed and with extrusion speed at constant drawdown ratio. After carefully characterizing the test resin in shear and extension, the similarities between predicted pure-shear (planar extension) transients and the tape experiments were studied. It was found that the trends, but not the magnitude of the experimental maximum stress were quite similar to the calculated longitudinal stress in pure shear. The behavior of the transverse to longitudinal stress ratio in pure shear was similar in behavior to the neck-in results, but considerable improvement was achieved by adding in a decayed stress from a simple-shear transient to simulate the conditions produced by the extrusion die. The philosophy of purposefully studying similarities between transient, pure or simple deformations and steady, complex processes is discussed.
    Additional Material: 12 Ill.
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