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  • 1
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    German Medical Science; Düsseldorf, Köln
    In:  121. Kongress der Deutschen Gesellschaft für Chirurgie; 20040427-20040430; Berlin; DOC04dgch0706 /20041007/
    Publication Date: 2004-10-07
    Keywords: ddc: 610
    Language: German
    Type: conferenceObject
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  • 2
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    German Medical Science; Düsseldorf, Köln
    In:  121. Kongress der Deutschen Gesellschaft für Chirurgie; 20040427-20040430; Berlin; DOC04dgch0703 /20041007/
    Publication Date: 2004-10-07
    Keywords: ddc: 610
    Language: German
    Type: conferenceObject
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  • 3
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Thermal Behaviour of Sulfates. III. The Behaviour of CdSO4 at High TemperatureThe behaviour of CdSO4 was studied by means of high temperature Guinier photographs in the temperature range of 20 to 960°C. Except N-CdSO4 which is the thermodynamically stable modification at STP, there are 3 high temperature modifications (M, H1 and H2-CdSO4) of which only metastable M-CdSO4 can be obtained kineticly stable at room temperature. The lattice constants and the structure type of H1- and H2-CdSO4 were determined. The structure of H1-CdSO4 is closely related with that of N-CuSO4 but in difference of N-CuSO4 it has a superlattice. H1-CdSO4 crystallizes orthorhombic with a325°C = 17.80 Å, b325°C = 7.35 Å, c325°C = 4.84 Å, Z = 8.H2-CdSO4 crystallizes hexagonal with a850°C = 5.01 Å, c850°C = 7.64 Å, Z = 2 in a modified NaKSO4 structure type (space group P 3m 1) with Cd2+ only in the Na+ positions. The temperatur and sequence of transitions as well as the thermal expansion of N- and M-CdSO4 was determined
    Notes: Mit Heizguinieraufnahmen wurde das Verhalten von CdSO4 im Temperaturbereich von 25-960°C untersucht. Außer der bei Raumtemperatur thermodynamisch stabilen Modifikation (N-CdSO4) existieren 3 Hochtemperaturmodifikationen (M, H1 und H2-CdSO4), von denen nur das metastabile M-CdSO4 bei Raumtemperatur kinetisch stabil zu erhalten ist. Metrik und Strukturtyp von H1- und H2-CdSO4 wurden bestimmt. H1-CdSO4 ist mit N-CuSO4 strukturverwandt, besitzt jedoch eine Überstruktur. Es kristallisiert orthorhombisch mit a325°C = 17,80 Å, b325°C = 7,35 Å, c325°C = 4,84 Å, Z = 8. H2-CdSO4 kristallisiert hexagonal mit a850°C = 5,01 Å, c850°C = 7,64 Å, Z = 2 in einem modifizierten NaKSO4-Typ (RG: P 3m 1); Cd2+ nur auf Na+-Punktlagen. Temperatur und Verlauf der Umwandlungen sowie die thermische Dilatation von N- und M-CdSO4 wurden bestimmt.
    Additional Material: 4 Ill.
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  • 4
    ISSN: 1573-3297
    Keywords: mating activity ; Drosophila persimilis ; chromosomal variants ; homokaryotypes ; heterosis for mating activity ; populational variation in mating activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Previous tests for mating activity ofDrosophila persimilis homokaryotype KL (Klamath) and MD (Mendocino) chromosomal arrangements (northern California population: Redwoods) had shown KL to mate faster on the average than MD in homogamic tests. A strain (double-cross hybrid of four KL lines from the same population) with reliable high mating activity was developed for testing the sexes separately. Five pairs of KL-MD homokaryotype strains were chosen to be tested by the criterion that each pair had been derived from a separate wild KL/MD progenitor. Strains were crossed within arrangements in a diallelic design (20 inter- and five intrastrain crosses tested in 16 replicates per cross) to provide mating activity indices of four sets: KL females, KL males, MD females, MD males. Mating tests employed ten virgin experimental flies with ten tester (double-cross hybrid) flies of the opposite sex in 30-min observation periods. All flies were matured for 5 days at 25°C before testing. Among parental strains, females were consistently higher in mating activity than males for both KL and MD arrangements. Most interstrain hybrids were heterotic, with KL and MD females not significantly different. However, hybrid MD males displayed greatest variation and had lowest mating activity, while KL males were the least variable and highest in mating activity. With heterosis in the hybrids, there was no predictability (additivity) from performance of parental strains to hybrid offspring. Mating activities of the two sexes were uncorrelated, indicating either that the sexes have independent genetic systems controlling mating activity or that the expression of the same genetic system is influenced by sex. Since the hybrid males of the two karyotypes displayed different courtship activity while the females were at about an equal level of receptivity, intrasexual selection among males is likely to be important in nature.
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  • 5
    ISSN: 1573-3297
    Keywords: minority mating advantage ; Drosophila melanogaster ; mating behavior ; male courtship cues ; habituation by female
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Alleles at the brown locus ofDrosophila melanogaster combined with homozygous scarlet provide a useful model to demonstrate minority advantage of males in mating. Heterozygotes with orange (O) eyes equal in numbers to homozygotes with red (R) eyes (10∶10 in both sexes) displayed no bias favoring either eye color, but each eye color was favored when males occurred in a minority ratio (2∶18). In direct observation of single females with equal numbers of males (3∶3) as controls,O males courted less and more slowly thanR males, but females mated with either type without bias. When unequal (4∶1), the minority males were successful at more than twice the frequency expected. Whether successful or not, the minority males did not change their level of courtship, and thus cannot be said to compensate for their frequency in any way. The time between first courtship and mating was less for the minority males than for the majority males. We discard the hypothesis that the minority male will be accepted immediately or ahead of a majority male, because the opposite tended to occur: that if a minority male courted first he was less likely to be successful than if he waited until the majority courted. Our results then are in conformity with the hypothesis that a female samples males and their courtship cues, thus becoming habituated to the majority of the first courting male, but she accepts a male with a cue different from that which she originally detected but avoided. That male is most often the minority.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1570-5846
    Keywords: Chow groups ; Milnor K-groups ; p-adic fields
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We investigate the Chow groups of zero cycles of products of curves over a p-adic field by means of the Milnor K-groups of their Jacobians as introduced by Somekawa. We prove some finiteness results for CH 0(X)/m for X a product of curves over a p-adic field.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1435-1536
    Keywords: Key words Polyacrylate ; Super absorber ; Diffusion NMR imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  The use of NMR imaging techniques for the characterization of superabsorbing polymers is explored. Spatial differences in the cross-link densities of polyacrylate-based superabsorbing particles are investigated by parameter-selective 1H NMR imaging of samples swollen with water. Images of the transverse relaxation time and of the self-diffusion coefficient of the absorbed water provide valuable information on the local water mobility and, thus, indirectly also on the polymer. The time evolution of the swelling process was also studied by NMR images acquired after different swelling times. Moreover, using magic-angle-spinning imaging, the influence of mechanical load on the swollen particle was investigated by taking advantage of the centrifugal forces on the spinning sample. These experiments indicate the presence of two water components, one strongly adsorbed, while the other is relatively mobile.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1435-1528
    Keywords: Key words Fourier-transform rheology ; Viscoelastic polymer solutions ; Non-linear regime ; High sensitivity FT-rheology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract  The application of oscillatory shear strain leads, in the non-linear regime, to the appearance of higher harmonic contributions in the shear stress response. These contributions can be analyzed as spectra in Fourier space, with respect to different frequencies, amplitudes and phase angles. In this article, we present an application of this new characterization method to a solution of the linear homopolymer polyisobutylene. The degree of non-linear response during oscillatory shear is quantified using the normalized intensity of the third harmonic contribution. We were able to show experimentally on polyisobutylene that there is an immediate onset of the non-linear response even for very small shear strain amplitudes.
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  • 9
    ISSN: 1435-1536
    Keywords: Key words Latex dispersions ; Film formation ; 1H and 2H solid-state nuclear magnetic resonance ; Water in polymer films
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  The properties of polymer films prepared from latex dispersions are influenced by the drying or film formation process. In order to investigate this process, various systems of aqueous latex dispersions were dried until a specific solid content was reached. The samples investigated were based on vinyl acetate, vinyl acetate/ethylene and pure acrylics employing different surfactants and polyelectrolytes as stabilisers of the dispersions. The role of water in these partially dried films was investigated using 1H and 2H solid-state NMR spectroscopy. Different types of water could be distinguished in the spectra. The drying latex films were found to contain interfacial external water, water at ionic and nonionic groups at surfactants in the polymer/water interface and also water inside the swollen polymer. These different types of water were examined separately using various NMR techniques.
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  • 10
    ISSN: 1573-0581
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The Tamayo transform fault occurs at the north end of the East Pacific Rise where it enters the Gulf of California. The two deep-tow surveys reported here show that the transform fault zone changes significantly as a function of distance from the spreading center intersections. At site 1, near the intersection, one side of the fault is young and the fault zone is narrow and well-defined. Strike slip occurs in a zone approximately 1-km wide suggesting a correspondingly narrow zone of decoupling between the Pacific and North American plates. On the young side of the strike-slip zone, normal faults occur along shear zones which are 45°–50° oblique to the transform strike. They occur parallel to the short axis of the strain ellipse for transform fault strain here, i.e., perpendicular to the least compressive stress. The transform walls are formed by normal faulting as has been pointed out in previous detailed surveys. Here, however, the age contrast of 2.5 m.y. across the transform valley is apparent in the morphology of the normal fault scarps. While the scarps are steep and well-defined on the young side, the scarps on the older side have gradual 10°–30° slopes and appear to be primarily talus ramps. Apparently, the scarps have been tectonically eroded by continued strike slip activity after the initial stages of normal faulting. Thus, transform valleys should be quite asymmetric in cross-section where there is a significant age contrast and one side is less than approximately 0.5 m.y. old. Also, along older sections of the transform valley walls, normal faulting may not be at all obvious due to degradation of the scarps by tectonic erosion. This phenomenon makes the likelihood of transform faults providing ‘windows’ into the oceanic crust most unlikely except in special cases. The picture of transform deformation is more complex at site 2 in the central portion of the fault where both sides of the fault are greater than 1 m.y. old. Here the transform valley is wider (25–30 km as opposed to 2–5 km). There is no clear simple zone of strike slip tectonics. In fact, the only clear evidence for deformation is the intrusion of magmatic or serpentinite diapirs through the sediments of the transform valley floor. The diapirs have deformed the turbidite layers flooring the valley and in one carefully studied case the turbidite sequence has been uplifted, perched atop the diapir. The pattern of deformation on this outcropping diapir shows radial and concentric fractures which can be modeled by a vertical intrusion circular in plan view. Magnetic studies limit the possible composition to basalt or serpentinite. A 60-km-long median ridge is also likely to be the product of intrusion along the transform fault. The survey at site 2 pointed out the importance of vertical tectonics in the transform valley floor and in particular the importance of diapiric intrusions of either basaltic or serpentinite composition. Based on initial boundary conditions and present tectonic elements in the Tamayo fault zone, a possible history of the mouth of the Gulf of California is outlined. The median ridge was emplaced starting approximately 0.8 m.y. ago by regional extension across the transform fault, the result of ‘leaky’ transform faulting. The diapirs occur along a possible ‘relay’ zone of extension midway along the fault which began approximately 0.15 m.y. ago. The extension in this case is parallel to the trend of the transform fault, is still occurring at present, and may evolve into a true spreading center.
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