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  • 2000-2004  (5)
  • 1970-1974  (5)
  • 1900-1904
  • 2000  (5)
  • 1974  (3)
  • 1970  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Clinical and experimental dermatology 25 (2000), S. 0 
    ISSN: 1365-2230
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
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    Unknown
    London, etc. : Periodicals Archive Online (PAO)
    British journal of psychology. 65 (1974) 85 
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 13 (1970), S. 363-376 
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Funktionen der Maxillartaster von Locusta migratoria migratorioides (R. & F.), Schistocerca gregaria (Forskål) und Chortippus parallelus (Zett.) wurden unter Anwendung verschiedener Verfahren untersucht. Die Tasterbewegungen wurden kinematographisch analysiert und als Schlagen und Tasten klassifiziert; das letztere tritt hauptsächlich kurz vor und nach, aber ebenso gut auch während der Nahrungsaufnahme auf. Die Sensillen an den Tasterenden berühren beim Tasten häufig das Substrat. Vorausgesetzt, daß die Insekten nicht gehungert hatten, wurde Bellis allein nach Betasten abgelehnt; nach längerem Hungern erfolgte jedoch die Ablehnung erst nach Beißen. Weitere Versuche, bei denen Extrakte der Kutikula von Poa oder Bellis verwendet wurden, zeigten, daß Annahme oder Ablehnung von der chemischen Natur des Substrats abhängen, welches von den Tastern berührt wird. Betasten eines geeigneten Substrats führte nicht unmittelbar zum Beißen, ruft aber eine Verhaltensweise hervor, die ihrerseits das Beißen fördert. Daraus wird geschlossen, daß die von den Tastern wahrgenommenen chemischen Reize für die Nahrungswahl der Acrididen wichtig sind, wenn die Insekten normal fressen. Nach Hunger ruft mechanische Reizung der Taster oder anderer Mundteile Beißen auch beim Fehlen geeigneter chemischer Reize hervor. Die häufigen kurzen Kontakte der Palpen mit dem Substrat während des Tastens erlauben offenbar den Sensillen, einen beständigen Strom von Informationen an das Zentralnervensystem zu liefern, ohne selbst angepaßt (ermüdet) zu werden.
    Notes: Abstract The functions of the maxillary palps of acridids have been investigated in experiments with Locusta migratoria migratorioides (R. & F.), Schistocerca gregaria (Forsk.) and Chorthippus parallelus (Zett.). The palp makes small irregular flicking movements and more extensive rapid vibrations described as palpation. Both activities involve the same basic movements of the palp segments. Palpation is essentially related to feeding and in normally feeding insects the palps play an important role in food selection, but as starvation is prolonged they become unimportant. Selection depends on appropriate chemical stimulation from the cuticle on the surface of the leaf. Palpation on this leads to head lowering and to biting if appropriate tactile stimuli are then received. The control of biting is discussed. The frequent but very brief, contacts of the sensilla on the tips of the palps with the substratum during palpation may enable them to relay information to the central nervous system more or less continuously without adapting.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 186 (2000), S. 13-19 
    ISSN: 1432-1351
    Keywords: Key words Catalpol ; Grammia ; Gustation ; Iridoid glycoside ; Phagostimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Caterpillars of the arctiid moth, Grammia geneura, are polyphagous, but species of Plantago are amongst their preferred food plants. A neuron in the medial styloconic sensillum on the galea has been shown to have a general phagostimulatory function. Experiments with binary mixtures and cross-adaptation have demonstrated that it responds to some sugars, to several amino acids, and also to catalpol. Catalpol is a plant secondary compound in Plantago and a phagostimulant for the caterpillars. The possible significance of combining sensitivity to nutrient compounds with sensitivity to a secondary compound is discussed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 38 (1974), S. 415-417 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Soft-X-ray and extreme ultraviolet spectroheliographs carried by the OSO-7 (Orbiting Solar Observatory) have been used to record the development of XUV emission associated with a flare of importance 1b on August 2, 1972. Spatial resolution was 20″ and spectral resolution was adequate to select emission lines originating within well-defined ranges of electron temperature between 5 × 104 and 30 × 106K. The data show that heating only the pre-existing coronal material adjacent to the flare site cannot account for the soft X-ray emission measure observed during the event. The flare emission originating at T e ⩽ 2.3 × 106K exhibits an impulsive component coincident with an impulsive microwave event. This radiation appears to coincide spatially with Hα radiation emitted at that time and is centered on the neutral line separating magnetic fields of opposite polarity. One soft X-ray-emitting feature, estimated to have an initial electron temperature of 2–10 × 106K, forms during the impulsive phase immediately over the Hα flare. A second, arch-like feature observed at wavelengths near 1.9 Å and estimated to have T e≅30 × 106K is located approximately 35000 km above the Hα event. Both regions have lengths of about 27000 km but transverse dimensions small compared to the spatial resolution of the spectroheliograph, i.e., less than 14000 km. The region with highest electron temperature exhibits the greatest stability in position. This region cools to approximately 10 × 106K in 6 to 12 min which is compatible with cooling by conduction to the chromosphere. The best association with a dark surge is found in an emission line of Fe xiv.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 38 (2000), S. 390-397 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. The toxicological significance of exposure of members of the public to spray drift odors of four herbicide formulations (three 2,4-dichlorophenoxyacetic [2,4-D] acid derivatives and one MCPA [4-methyl-2-chlorophenoxyacetic acid] derivative) has been studied using a combination of novel odor measurement and classic residue analysis techniques. The mean odor concentrations, generated during the spraying of the commercial herbicide formulations under simulated aerial application conditions, were about twofold higher for 2,4-D ethylhexyl ester (22,500 OUc/m3) and MCPA (30,100 OUc/m3) than for 2,4-D butyl ester (12,400 OUc/m3) and 2,4-D amine (11,800 OUc/m3). Detailed investigations determined that the odors are due to trace manufacturing impurities and additives in the commercial formulations, whereas the herbicide active ingredients are odorless. Measured airborne herbicide active ingredient concentrations under the simulated aerial application conditions were all below their respective occupational safety and health TLV-TWA values, indicating that exposures of toxicological significance as a result of spray drift are unlikely.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We examined population structure in the wreckfish, Polyprion americanus, by assaying six microsatellite loci in 422 individuals collected throughout the geographic range. Eighteen hapuku, P. oxygeneios, were assayed at the same loci for use as an outgroup. Expected heterozygosities ranged from 0.49 to 0.88 and averaged 0.66. Allele-frequency distributions at those loci indicated that samples from the eastern North Atlantic, western North Atlantic and the Mediterranean were genetically similar, confirming the pattern seen in a previous analysis of mitochondrial DNA (mtDNA) restriction fragment length polymorphisms (RFLPs). Both mtDNA and microsatellite studies differentiated northern and southern wreckfish stocks. However, in contrast to the mtDNA studies, allelic variation at microsatellite loci clearly differentiated wreckfish from two Southern Hemisphere locations, Brazil and the South Pacific. Far more genetic variation was observed at microsatellite loci than with mtDNA RFLPs (haplotype diversity averaged 0.01), and we saw more evidence of population structure with the microsatellite loci. The differentiation between southern and northern wreckfish supports the distribution records, which indicate that wreckfish do not occur in the tropics. Temperature profiles and current patterns throughout the southern oceans apparently also prevent significant gene flow between the South Pacific and Brazilian samples.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-1561
    Keywords: Heliothis virescens ; Heliothis subflexa ; caterpillar ; diet breadth ; deterrent compound ; feeding behavior ; postingestive toxicity ; plant secondary metabolite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Sensitivity of caterpillars of Heliothis virescens, a generalist, and H. subflexa, a specialist, to eight different plant secondary compounds was examined behaviorally. The compounds were nicotine hydrogen tartrate, hordenine, caffeine, sinigrin, linamarin, arbutin, chlorogenic acid, and salicin. All compounds deterred feeding, at least at the higher concentrations, but the generalist was less affected than the specialist. Thus the hypothesis that specialists have greater sensitivity to deterrents than generalists was supported. In most cases deterrence occurred on first encounter, indicating that the response was sensory; in some cases short-term postingestive effects also appeared to play a role. The larger quantities of deterrent-containing food ingested by H. virescens sometimes resulted in measurable postingestive effects during the second control test. This did not occur in H. subflexa, which more commonly rejected the deterrent-containing food on first contact. The contrast between the species is discussed in relation to tradeoffs involved in different diet breadths.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 445-457 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The change in apparent molal volume φ of DNA on thermal denaturation in carbonate buffer at pH 11.0 has been determined by the dilatometric method. It was found that φ increases sigmoidally during the helix-coil transition. Several methods, including a colorimetric technique that closely simulates the conditions used in the dilatometric experiments, were employed to estimate the protons lost by the DNA during the transition. These measurements indicated that the extent of the proton loss depends on the counterion present, increasing in the order Li+ 〈 Na+ 〈 K+ 〈 Cs+. The major part of the volume changes observed during the denaturation is due to the volume changes expected to accompany the transfer of protons from the bases guanine and thym ne to carbonate ions. As has been previously reported for the denaturation of DNA at neutral pH, the volume change directly due to the change in shape of the polymer molecules is so small as to be experimentally undetectable.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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