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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 137 (2000), S. 559-565 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The upper critical thermal limits were measured as heat-coma temperatures in Littorina species as a tool for examining physiological diversity. Thermal tolerance was found to be stable within a population, but extensive variation occurred between populations and species. All species examined displayed heat-coma values of ∼30 °C and did not show a positive correlation with shore height. Eulittoral-fringe species tended to have higher coma temperatures than eulittoral species. Coma temperatures varied both seasonally and geographically. Lethal thermal limits were also investigated; these were ∼10 C° higher than coma temperatures.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 137 (2000), S. 447-451 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The nature of heat coma was examined in the edible periwinkle Littorina littorea (L.). Duration of acclimation did not influence heat-coma temperature at 12 °C, although other acclimation temperatures were important in influencing thermal tolerance, with positive shifts in coma temperature observed in response to elevated temperatures. Previous thermal history also influenced heat-coma temperatures. Individuals subjected to repeat heat-coma events on a daily basis showed significant declines (P 〈 0.05) in coma-temperature; in contrast individuals exposed to repeat heat-coma events on a weekly basis showed no decline in thermal tolerance. Size-effects occurred at selected sites, where decreased heat-coma temperatures were recorded in large individuals.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 96 (1975), S. 37-52 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The roles of certain abdominal muscles in ventilatory behaviour are discussed and illustrated with records of muscular activity obtained mainly from free-swimming animals. The following muscles are shown to be active during normal ventilation (V n): respiratory and anterior dorso-ventrals (RDV and ADV), longitudinal tergal (LT), diaphragm, sub-intestinal and adductors of the anal appendages (VADP). The posterior dorso-ventral, lateral primary longitudinal sterno-pleural, and dorso-ventral oblique muscles were found to be inactive duringV n. TheRDV, ADV, LT andVADP are also active during ventilatory movements other thanV n.RDV activity is shown to be more variable in the free-swimming animal than recordings from dissected and restrained preparations previously suggested. Activity in theADV duringV n shows a reciprocal relationship with that in theRDV. Postulated control elements in larval ventilation are found to parallel many described in other ventilatory systems and motor rhythms generally.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 97 (1975), S. 329-338 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Jet-propulsion in dragonfly larvae is achieved by the rapid ejection of water from a specialised rectal chamber via the anus, at a frequency of up to 2.2 cycles/s. Movement, forward thrust and muscular activity have been recorded in restrained and free-swimming larvae. Forward thrusts of up to 1.5 g wt result from the expiratory phases of cycles lasting 0.1 to 0.4 s. Swimming velocities are in the order of 10 cm/s. The following muscles are shown to be active during expiratory phases of jetting: anterior, posterior and respiratory dorso-ventrals; primary and secondary longitudinal tergals; lateral primary longitudinal sternopleural; dorso-ventral oblique; ventral adductors of the anal appendages. The sub-intestinal muscle is active during the inspiratory phases of jetting. Activity recorded is compared with that found during normal ventilation. The larval jet-propulsive mechanism is compared with that of certain cephalopods and found to be very effective for the larva's relatively small size.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 182 (1958), S. 174-175 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] THE secretion of the coagulating gland of the male guinea pig induces a hypotensive shock on intravenous injection into the guinea pig and the rabbit, and oedema on local injection into the tissues1. The induction of oedema suggested that these effects were produced by substances increasing the ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 185 (1960), S. 246-247 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Guinea pig serum was harvested from defibrinated blood5 and stored at 2 C. The excised tissues were freed of adherent connective tissue bearing blood vessels and disrupted6 in sterile 0-85 per cent saline, using a loosely fitting homogenizer of the Potter type. The homogenate was centrifuged at ...
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 229 (1971), S. 206-208 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The PD organ monitors the relationship between the two most distal leg joints (dactylopodite and propodite)1'2. It consists of numerous sensory cells with dendrites which are embedded in a strand of tissue containing collagen and supporting cells. Some sensory cells monitor position, others ...
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 119 (1977), S. 63-72 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anterior and posterior proprioceptors at the tibio-metatarsal joint of the cribellate spiderCiniflo have been studied physiologically by recording from the individual receptor nerves in response to manipulation of the metatarsus. In the anterior organ (TMant) two flexion sensitive movement units, an extension sensitive position unit and a flexion sensitive position unit were identified (Figs. 2 and 3). In the posterior organ (TMpost) there are more units present, with representatives of the above categories and also some indication of an extension sensitive movement unit (Fig. 6). The results are compared with those of the corresponding receptors in crustaceans.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 119 (1977), S. 37-54 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The electrophysiological responses to mechanical stimulation of the four commonly occurring types of hair sensilla on the legs of the cribellate spiderCiniflo are described. The long, straight ‘tactile’ hairs respond preferentially to depression with activity from two phasic receptor units, one of which is sensitive to higher movement velocities than the other (Fig. 3). The units innervating the large spines respond only during erection. There is a fast adapting phasic unit and a slower adapting phaso-tonic unit (Figs. 4 and 5). It is suggested that these spines may serve partly as haemocoelic pressure monitors. The delicate trichobothria respond to small movements in all directions with directional responses from three phasic units, and are the only hairs showing true, directional sensitivity (Figs. 9, 10 and 11). The curved, blunt-tipped ‘chemoreceptive’ hairs show activity from one phasic unit when the hair is deflected in any direction away from its rest position (Fig. 8). In all cases, the number of physiologically detectable cells is one less than has been shown to be present ultrastructurally. The possible significance of these observations in relation to general araneid behaviour is discussed.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 119 (1977), S. 55-62 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The curved, blunt-tipped hairs on the legs ofCiniflo have a structure characteristic of contact chemoreceptors. Using a ‘hair tip’ recording technique, it has been possible to confirm that these sensilla do respond to contact stimulation by certain chemical substances (Figs. 1 and 3). A few experiments were also performed onTegenaria (Fig. 2). So far, positive responses to some monavalent salts (Figs. 1 and 2) and hydrochloric acid (Fig. 3) have been established, involving perhaps 5 to 6 chemoreceptor units in all. However, each sensillum is known to have 19 chemoreceptor cells and thus most of the reaction spectrum of the sensillum remains unknown. The suggestion that, in contrast to insect contact chemoreceptors (which usually have only 4–7 sensory units), some of the dendrites may be very specific receptor units and are perhaps involved in the detection of contact pheromones or other equally specific substances, is discussed.
    Type of Medium: Electronic Resource
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