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  • Chemistry  (82)
  • GEOPHYSICS  (55)
  • Cell & Developmental Biology  (12)
  • Lepidoptera  (9)
  • METEOROLOGY AND CLIMATOLOGY
  • Meteorology and Climatology
  • 1995-1999  (43)
  • 1990-1994  (124)
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  • 1
    ISSN: 1570-7458
    Schlagwort(e): Lepidoptera ; Pyralidae ; Ectomyelois ceratoniae ; carob moth ; host-finding ; Phoenix dactylifera ; dates ; gas chromatography-electrophysiology ; mass spectrometry ; wind tunnel ; attraction ; volatiles ; headspace
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Four volatile compounds emitted from fungus-infected date fruit,Phoenix dactylifera L., were identified using coupled gas chromatographic-electroantennographic recordings, coupled gas chromatographic-mass spectrometric analysis, electroantennographic assays of synthetic standards, and wind tunnel bioassays. These compounds were ethyl hexanoate, ethanol, acetaldehyde, and 2-phenylethanol. Wind tunnel bioassays showed that ethyl hexanoate was capable of stimulating upwind flight and landing on the source by mated female carob moths,Ectomyelois ceratoniae (Zeller). Addition of both ethanol and acetaldehyde to ethyl hexanoate resulted in an increase in attraction to a level similar to that found for date fruits. No such effect was noted for additions of 2-phenylethanol at the dosages tested. In this study, it appears that ethyl hexanoate is a dominant olfactory stimulant and attractant for mated female carob moths, and represents a novel compound with regard to previously identified lepidopteran host odor attractants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of insect behavior 7 (1994), S. 605-632 
    ISSN: 1572-8889
    Schlagwort(e): Heliothis ; Lepidoptera ; Noctuidae ; pheromone ; visual feedback
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract MaleHeliothis virescens (F.) (Lepidoptera: Noctuidae) were made to fly into a uniformly white and translucent tube within a large wind tunnel while responding to sex pheromone. Different visual patterns placed within the tube greatly affected the ability of the male moths to maintain upwind progress or remain oriented to the wind while in contact with the plume. Over 89% of males attempting to fly through a blank tube, lacking visual patterns, became disoriented, the males gaining or losing altitude and repeatedly hitting the sides of the tube. Patterns of 20–40 dots placed on the sides of the tube at or slightly above plume level resulted in high levels of sustained upwind flight (47–74%) relative to patterns placed directly below (30–40%), directly above (35%), or slightly below the level of the flight path (26–44%). Optimal upwind progression in pheromone-responding males occurred when image motion could be resolved both transversely (T), orthogonally to the longitudinal axis of the body relative to the horizontal plane of the environment, and longitudinally (L), along the body axis. Even very sparse patterns (single rows of dots) could elicit high levels of sustained upwind flight (53–63%) when positioned within the tube such that the males' movements would create both L and T image motion. However, successful negotiation of the tube was also unexpectedly facilitated by patterns apparently providing no horizontal transverse component for flying males but providing longitudinal flow while centering the moth in the plume through a symmetrical left-right input (4–40%).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 1572-8889
    Schlagwort(e): Heliothis virescens ; Noctuidae ; Lepidoptera ; upwind flight ; sex pheromone ; filaments
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Aspects of the intermittent fine structure of an odor plume were mimicked and experimentally modified in the wind tunnel using an air-pulsing device. Filaments of a behaviorally active blend of six sex-pheromone components created by the device in a temporally regular fashion elicited sustained upwind flight and source location in male Heliothis virescens.Males did not exhibit sustained upwind flight in significant numbers until a frequency of 4 filaments/s was delivered, at a loading of 1 μg of the major component, Z11-16: Ald, with the other components loaded at their appropriate ratios. A loading of 10 μg Z11-16: Ald was found to be optimal at this filament delivery rate. Electroantennogram recordings to different filament delivery rates of the complete blend indicated that a stationary male antenna can respond to the pulse rates used in this study. Importantly, when a main component necessary for upwind flight, Z9-14:Ald, was isolated into its own filaments and pulsed alternately against filaments of the five other components (including the other component essential for upwind flight, Z11-16: Ald), upwind flight to the source was significantly reduced (9%) compared to upwind flight and source location in response to filaments composed of the entire blend (30%), indicating that the complete pheromone blend must arrive on the antenna simultaneously for optimal evocation of sustained upwind progress. Neurophysiological evidence from other studies suggests that higher-order interneurons whose phasic response is enhanced when the entire blend is presented simultaneously may be of importance in explaining this behavioral difference stemming from synchronous vsasynchronous arrival of the components.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Journal of comparative physiology 185 (1999), S. 131-141 
    ISSN: 1432-1351
    Schlagwort(e): Key wordsHelicoverpa zea ; Noctuidae ; Lepidoptera ; Sex pheromone ; Antagonist
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The limits of a male moth's ability to resolve closely spaced odor filaments have been investigated. Male Helicoverpa zea normally respond to their conspecific sex pheromone blend by exhibiting an upwind flight, which culminates in source contact by at least 50% of the bioassayed individuals. When loaded onto the same filter paper source containing this hitherto attractive pheromone blend, or onto a separate filter paper and co-emitted from the same pipette source with pheromone, (Z)-11-hexadecenyl acetate severely reduced upwind flight and source contact by male H. zea. A similar level of upwind flight inhibition was recorded when the antagonist (Z)-11-hexadecenyl acetate was emitted from its own point source placed 1 mm upwind of the pheromone point source, both plumes being simultaneously emitted in a continuous mode to form a confluent strand. However, (Z)-11-hexadecenyl acetate was less effective in reducing upwind flight and source contact when it was isolated and pulsed from its own source, placed 1 mm either upwind, downwind or cross-wind of a pipette source from which pheromone was simultaneously being pulsed, such that both filaments were separated in time by 0.001–0. 003 s. These results suggest that male H. zea are able to distinguish between odor sources separated by as little as 1 mm in space and 0.001 s in time.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1432-1351
    Schlagwort(e): Heliothis ; Noctuidae ; Lepidoptera ; Plume structure ; Behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract 1) Male Heliothis virescens moths flew upwind to pulsed pheromone plumes. Upon truncation of the pulsed plume males flew into clean air, turning their tracks crosswind (〉 60° relative to directly upwind direction at 0°) within an average of 0.27 s, and were casting, perpendicular to the wind-line (90°), within 0.43 s. 2) The characteristic casting flight in clean air consisted of left-right crosswind reversals, continuing for many seconds without further pheromonal stimulation. Males intercepting a single strand of pheromone during casting flight responded by surging upwind (track angles 〈 60°). The phasic surge lasted only 0.38 s before reverting to crosswind flight (〉 60°). 3) Average templates of responses in two and three dimensions were created. Males controlled their vertical deviations very tightly when in contact with pheromone but upon entering clean air, lateral and vertical excursions became much greater. 4) Males failed to sustain upwind flight to repetitively pulsed plumes generated at 〈 4 filaments/s. At the threshold frequency of 4 pulses/s we show that upwind flights were composed of reiterated surges followed by crosswind casting. As the pulse frequency increased, the tracks became straighter and the single filament cast-surge-cast template could be viewed only sporadically when, for example, a male apparently failed to intercept filaments.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 1573-1561
    Schlagwort(e): Lepidoptera ; Pyralidae ; sex pheromone ; (Z,E)-9,11,13-tetradecatrienal ; mimic ; (Z,E)-7,9,11-dodecatrienyl formate ; wind tunnel ; attractant ; electrophysiology ; receptor cell
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The behavioral and electrophysiological activity of a mimic [(Z,E)7,9,11-dodecatrienyl formate] of the major sex pheromone component [(Z,E) 9,11,13-tetradecatrienal] of carob moth was assessed. Wind-tunnel bioassays demonstrated that the formate was as effective as natural gland extracts, and significantly more effective than the trienal alone or than the trienal blended with two minor pheromone components, in evoking source contact. Dispensers containing the formate were as effective as trienal-containing blend lures in attracting males when placed at the same dosage in traps in date gardens. Single-cell recordings showed that at least two olfactory neurons, differentiated by spike amplitude, are located in the long trichoid hairs on male carob moth antennae. Dose-response relationships indicated that puffs from cartridges loaded with at least 0.1 μg of the formate or of the trienal were necessary to elicit spiking by either the small or the large-spiking cell within a sensillum. Cross-adaptation studies demonstrated that both compounds stimulated the same large-spiking cell. The frequencies of spikes evoked from the large cell when stimulated by emissions from 0.1-μg, 1-μg, or 10-μg cartridges of either the formate or the trienal were not significantly different, suggesting that the formate is an effective mimic of the trienal at the antennal receptor cell level.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Journal of comparative physiology 182 (1998), S. 585-594 
    ISSN: 1432-1351
    Schlagwort(e): Key wordsHelicoverpa zea ; Noctuidae ; Lepidoptera ; Single-cell recordings ; Antennal neurons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Responses of single receptor neurons in the antennae of male Helicoverpa zea to sex pheromone components and to behavioral antagonists were recorded using a cut-sensillum extracellular recording technique. Three types of sensilla were identified from sampling 325 male-specific sensilla trichodea located at the lateral edge of antennomeres. The majority of these sensilla (71%) contained a receptor neuron tuned to the principal sex pheromone component (Z)-11-hexadecenal. A second sensillar type (10%) contained a receptor neuron that responded only to (Z)-9-tetradecenal. A third sensillar type (19%) contained a large-spiking neuron tuned to the secondary pheromone component (Z)-9-hexadecenal, but this neuron also could be stimulated to equivalent spike frequencies by the same emitted amounts of (Z)-9-tetradecenal. A smaller-spiking neuron in this sensillar type responded to two compounds known to act only as behavioral antagonists, (Z)-11-hexadecen-1-ol and (Z)-11-hexadecenyl acetate, and to (Z)-9-tetradecenal. Cross-adaptation studies confirmed the presence of one large- and one small-spiking neuron in the third sensillar type. Dose-response studies correlated to collected stimuli amounts showed that the large-spiking neuron in the third sensillar type was equally tuned to (Z)-9-hexadecenal and (Z)-9-tetradecenal, whereas the smaller-spiking neuron was far more sensitive to (Z)-11-hexadecen-1-ol and to (Z)-11-hexadecenyl acetate than to (Z)-9-tetradecenal.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A series of Melanin-concentrating hormone (MCH) fragments have been synthesized and their biological activities compared with the parent peptide. The substructural units, 5-14 linear and 5-14 cyclic, have been used as models for MCH -  in 1H-nmr conformational studies. Conformational features predicted by molecular dynamics analyses find support in the nmr experiments.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 377-382 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The viscoelastic responses of some molten polymers, and particularly of low density polyethylene (LDPE), are known to vary with processing history. Reasons for the variations include the effects of shear history on morphological states of the polymer, or on its molecular weight parameters. A typical low density polyethylene has been used to test the shear-history dependence concept following a variety of processing steps. The polymer was sheared in single-screw and twin-screw extruders, and in a high speed melter / mixer (Gelimat). Samples also were precipitated from very dilute solutions in trichlorobenzene and in p-xylene. GPC analyses showed that, in general, these procedures did not affect the various moments of molecular weight. An exception was the Gelimat-mixed sample, for which mild reductions in Mn and Mw were noted. In contrast, melt viscosity and elasticity readings, the former from low shear evaluations and the latter from extrudate swelling, were affected by the various procedures. A drop in melt viscosity and in elasticity was observed, being most pronounced for precipitated and twin-screw extruded versions of the LDPE. Reductions also were observed in the specimen sheared in the Gelimat instrument. Following conditioning at the test extrusion temperature (170°C), viscous and elastic responses tended to revert to those of the unsheared control sample, the exception again being the sample sheared in the Gelimat melter / mixer. Of the various mechanisms proposed in the literature to account for transient property changes such as those reported, temporary changes in the degree of chain entanglement appear the most satisfactory explanation. Irreversible alterations in viscoelastic properties may be associated with changes in molecular weights due to processing at high shear.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Previous studies by Stephens and McNulty and Strecker and Stephens have demonstrated that foil barriers placed between the mesonephros and lateral plate at stages 12 to 15 inhibited limb development, but foil barriers placed between the neural tube and somites at stages 11 to 12 resulted in limbs with normal skeletal patterns. It was concluded that some influence present in the paraxial region of the embryo at stages 11 to 15 is necessary for normal limb development. The present study was undertaken to localize that influence more precisely. Foil barriers were placed in the lateral edge of the somites or segmental plate of stage 10 to 15 chick embryos. Barriers placed into stage 13 to 15 embryos resulted in chicks with normal limbs, but barriers placed into stage 10 to 11 embryos resulted in chicks with defective limbs. Barriers inserted just lateral to Hensen's node at stages 6 to 8 resulted in embryos with defective or absent wings. We also grafted stage 4 to 9 presumptive limb territories with and without Hensen's node. Explants without Hensen's node formed limb-like structures in 1% of the cases. Explants with Hensen's node formed limb-like structures in 27% of the cases. When barriers were implanted and a node was placed on the lateral side of the barrier, limbs formed in 40% of the cases. These data suggest a medial to lateral progression of some as yet unknown morphogenetic influence necessary for normal limb development and we hypothesized that the influence may initially emanate from Hensen's node.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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