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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 36 (1980), S. 109-115 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract In the imagines of the mealworm Tenebrio molitor vigorous head movements during walk have been observed. This head waving is absent in resting animals. The time course of the head movement in the horizontal plane of the tethered animals was registered by means of a television camera and its power spectrum, autocorrelation function as well as the distribution of the head's angular position have been calculated. In non-homogeneous stationary panoramas, which are symmetrical with respect to the body axis the process governing the head waving is quasi-Gaussian, its power spectrum is a slowly declining exponential function of the frequency. In asymmetrical panoramas the distribution of the angular position of the head becomes also asymmetrical, and its average value is shifted with respect to the body axis. In homogeneously bright surroundings the process is the superposition of a quasi Gaussian and of a symmetrical periodic function, thus indicating a regular searching movement in addition to the random head waving. The possible role of the head waving for the fixation response is discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biological Psychology 13 (1981), S. 31-49 
    ISSN: 0301-0511
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Psychology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physics Letters B 300 (1993), S. 404-409 
    ISSN: 0370-2693
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neural transmission 54 (1982), S. 285-291 
    ISSN: 1435-1463
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Auditory brain stem evoked responses (BSERs) were recorded from schizophrenic and depressed patients and healthy subjects. Between these groups no differences in latencies, amplitudes and variability of the BSERs were found.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 36 (1980), S. 117-124 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract Tethered walking imagines of the mealworm beetle Tenebrio molitor wave their heads in random fashion. If a periodic pattern of vertical black and white stripes is rotated around the animal a regular nystagmic head movement is superimposed upon the random waving, the frequency of the latter equals the contrast frequency within large ranges of the angular velocity of the pattern. The nystagmus is inverted: After a short period of tracking, during which the angular velocity of the head is the same as that of the panorama, the head returns slowly toward its normal position according to an exponential-like function. Resting animals do not wave their heads. However, if the above panorama is rotated, the beetle turns its head in the direction of the movement of the panorama and holds it in a side-way position, as long as the rotation is maintained. The angular position reached depends in the same manner on the angular velocity of the panorama as the turning tendency of walking animals established in open loop experiments using the spherical Y-maze method.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 41 (1981), S. 1-3 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract Head movements of different species of walking beetles elicited by rotating stripe patterns have been investigated. They are of the usual type in contrast to an “inverted nystagmus” reported forTenebrio molitor in similar experimental situations. Reexamination of theTenebrio records revealed that the sign of the stimulus was interchanged by a mistake while plotting the results. Thus, the head nystagmus inTenebrio is also of the usual type, consisting of a smooth pursuit head movement followed by a faster returning phase.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] New Zealand and Dutch Belted rabbits (not operated upon or surviving 3-143 days after unilateral optic nerve section or eye enucleation) were used. Most received an intraocular injection of colchicine, which is known to increase peptide levels in neuronal cell bodies4. Some received a unilateral ...
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 77 (1989), S. 234-244 
    ISSN: 1432-1106
    Keywords: Development ; Visual cortex ; Slicecultures ; Pyramidal cells ; GABA immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Slice cultures from the visual cortex of young rats were prepared using the roller culture technique (Gähwiler 1984). After 10 days in vitro the cortical cultures flattened to 1–3 cell layers, surviving for up to 12 weeks. The cultures were organotypically organized, the typical layered structure of the cortex was preserved. The neuronal composition of slice cultures was studied using intracellular staining, Golgi impregnation and GABA immunohistochemistry. Both pyramidal cells and several types of nonpyramidal cells were identified in the slice cultures. Electrophysiological recordings showed that the electrical properties of cells in culture were similar to those measured in acute slice preparations; for some cells, however, the spontaneous activity was higher. The maintained activity was strongly increased by application of the GABA antagonist bicuculline and decreased by GABA, suggesting that GABAergic inhibition is present in these preparations. We could observe the postnatal maturation of some characteristic morphological features in culture. For example, pyramidal cells in 6 day-old rats in situ have very short basal dendrites with growth-cones, and the dendrites are free of spines. After 2–3 weeks in culture growth-cones were no longer observed. Instead, the cells had developed a large basal dendritic field and the dendrites were covered with spines. Slice cultures therefore may provide a useful tool for physiological, anatomical, pharmacological and developmental studies of cortical neurons in an organotypical environment.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 25 (1976), S. 351-357 
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Mössbauer spectra of119Sn in Sn1−z Eu z Mo6S8 (z=0, 1/3, 2/3) have been measured in the temperature range 4.9 K≦T≦293 K. The spectra consist of a quadrupole doublett with unequal intensities at all temperatures. The Debye-Waller factor, the isomeric shift and the asymmetry of the intensity of the quadrupole components show irregularities between 50 K and 110 K which are interpreted as arising from a structural phase transition. The temperature dependence of the Debye-Waller factor can be approximated by a simple phonon spectrum. No quantitative explanation can be given for the large values of the asymmetry. Evidence is presented that this behavior is connected with the properties of the librational modes of the Mo6S8-units in the crystal.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 20 (1975), S. 95-103 
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Mössbauer spectra for119Sn in crystalline and disordered Sn, as well as in crystalline and liquid-like amorphous Sn1-x Cu x (X=0.10−0.18), have been measured at 2.6 K≦T≦108 K. The Debye-Waller-Factor (DWF) obtained from the spectra is identical for the crystalline and for the disordered phase. The DWF of the amorphous phase is smaller than the DWF of the crystalline phase athigh temperatures, but it shows a stronger temperature dependence than the DWF of the crystalline phase and reaches the latter one at about 4 K. From this low-temperature result we conclude that the differences of the Eliashberg functionα 2(ω)F(ω) and of the superconducting transition temperatureT c in these two phases cannot be related to changes in the phonon spectrumF(ω), but must result from changes of the interaction parameterα 2 (ω). A comparison between DWF,α 2 F, and specific heat data is performed. From the values for the isomeric shift of the Mössbauer line we can show that the hybridisation and covalency of the electronic bonds present in the crystalline and in the disordered phases are destroyed in the amorphous phase. Both, the DWF and the isomer shift demonstrate that the electronic properties of crystalline and amorphous Sn(Cu) differ appreciably. The electronic and superconducting properties of amorphous Sn(Cu) are similar to the properties of the high pressure phase of tin.
    Type of Medium: Electronic Resource
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