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  • 1
    Electronic Resource
    Electronic Resource
    Distribution of phytoplankton communities in relation to the large-scale hydrographical regime in the Fram Strait (1991)
    Springer
    Marine biology 111 (1991), S. 311-321 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In June and July 1984 phytoplankton distribution was investigated in the Fram Strait between Greenland and Svalbard. Chlorophylla, particulate organic carbon, nitrate and phytoplankton species composition were determined from six different depths in the upper 200 m of the water column. Multivariate analysis methods were applied to identify phytoplankton communities in relation to different hydrographic regimes. Three main domains could be distinguished in terms of both hydrography and biology: (1) the East Greenland shelf polynya with a high biomass mainly produced by chain-forming diatoms, (2) the ice-covered East Greenland Current with an extremely low standing stock dominated by flagellates and (3) the marginal ice zone with a biomass maximum in 20 to 40 m depth formed by diatoms, dinoflagellates andPhaeocystis pouchetii.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01319714
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  • 2
    Electronic Resource
    Electronic Resource
    Vertical fine structure of the biomass and composition of algal communities in Arctic pack ice (1999)
    Springer
    Marine biology 133 (1999), S. 745-754 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biomass and composition of algal communities in sea ice were studied during two summer expeditions to the central Arctic Ocean and the Greenland Sea. Based on algal pigment determination and cell counts, high biomass accumulations were found at the surface, in the interior and in the bottom layer of the ice floes. Pennate diatoms dominated in the bottom layer, while phototrophic flagellates and cysts of unknown origin were the most abundant taxa in the upper parts. The lowermost 20 to 40 cm contained between 4 and 62% of the entire algal biomass. Consequently, ice biological studies, which deal only with the bottom few centimetres of the ice floes, will underestimate algal biomass and production by factors of up to 25. Differences between the results of this study and published data from coastal locations point towards different biological regimes in Arctic sea ice. The algal biomass in coastal ice is about two orders of magnitude higher and composed mainly of diatoms, probably supported by nutrient influx from the water column. In the pack ice of the central Arctic, nutrient supply is probably reduced, and flagellates contribute substantially to total algal biomass. However, methodological problems might partially be responsible for the observed differences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050516
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  • 3
    Electronic Resource
    Electronic Resource
    Limitations of Artificial Hip Joint Mobility Due to Wear and Ceramic Cup Design (2000)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 192-195 (Sept. 2000), p. 549-552 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/45/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.192-195.549.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    On the structure and development of Arctic pack ice communities in Fram Strait: a multivariate approach (1992)
    Springer
    Polar biology 12 (1992), S. 727-733 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The distribution of ice organisms was investigated in Fram Strait in May 1988 during the ARK V/1 expedition on RV Polarstern. Over a 3 week period the abundances of bacteria, diatoms, auto- and heterotrophic flagellates as well as various groups of meiofauna organisms were observed in the lowermost 30 cm of an ice floe. Data were obtained from three experimental fields under three different light regimes as a result of manipulations of the snow cover. The application of multivariate factor analysis on this time series data set resulted in the characterization of four succession stages of an Arctic sea ice community: 1) the diatom bottom assemblage, 2) the mixed autotrophic assemblage, 3) the mixed auto- and heterotrophic supra-bottom assemblage, and 4) the heterotrophic supra-bottom assemblage. The two most abundant meiofauna groups (Turbellaria, Ciliata) showed different preferences according to algal distribution. While turbellarians were most abundant in samples with mixed populations of diatoms and flagellates, ciliates reached their abundance maxima in samples dominated by diatoms, suggesting different prey selections. We have developed a model for the explanation of the spatial separation of auto- and heterotrophic organisms, highlighting the possible role of DOC production by ice algae and DOC transport with brine flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238874
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  • 5
    Electronic Resource
    Electronic Resource
    Seasonal occurrence of picocyanobacteria in the Greenland Sea and central Arctic Ocean (1995)
    Springer
    Polar biology 15 (1995), S. 447-452 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The seasonal occurrence of picocyanobacteria in the Greenland Sea and Arctic Ocean was investigated during four expeditions in May–June 1987 and 1988, August–October 1991, and November–December 1988 by epifluorescence microscopy. In early summer, the abundance of picocyanobacteria was related to water masses: they were nearly absent in polar water, whereas they occurred in high concentrations (up to 5470 cells ml−1) in Atlantic Water. During autumn and beginning of winter, the abundances of picocyanobacteria remained around 103 cells ml−1. Their relative contribution to total picoplanktonic algal abundance increased from 0% during spring/summer to 70–80% in late autumn, as a result of a decrease in the abundance of eucaryotic picoalgae. Consequently, the impact of picocyanobacteria on Arctic epipelagic carbon and energy flow is of minor importance, and the strong contribution of picoplankton algae to biomass and primary productivity in Arctic seas has to be attributed to eucaryotic species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239722
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  • 6
    Electronic Resource
    Electronic Resource
    Integrated abundance and biomass of sympagic meiofauna in Arctic and Antarctic pack ice (1999)
    Springer
    Polar biology 22 (1999), S. 169-177 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The abundance and biomass of sympagic meiofauna were studied during three cruises to the Antarctic and one summer expedition to the central Arctic Ocean. Ice samples were collected by ice coring and algal pigment concentrations and meiofauna abundances were determined for entire cores. Median meiofauna abundances for the expeditions ranged from 4.4 to 139.5 × 103 organisms m−2 in Antarctic sea ice and accounted for 40.6 × 103 organisms m−2 in Arctic multi-year sea ice. While most taxa (ciliates, foraminifers, turbellarians, crustaceans) were common in both Arctic and Antarctic sea ice, nematodes and rotifers occurred only in the Arctic. Based on the calculated biomass, the potential meiofauna ingestion rates were determined by applying an allometric model. For both hemispheres, daily and yearly potential ingestion rates were below the production values of the ice algal communities, pointing towards non-limited feeding conditions for ice meiofauna year-round.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003000050407
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  • 7
    Electronic Resource
    Electronic Resource
    Potential effect of ice formation on Antarctic pelagic copepods: salinity induced mortality of Calanus propinquus and Metridia gerlachei in comparison to sympagic acoel turbellarians (1998)
    Springer
    Polar biology 20 (1998), S. 139-142 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The salinity tolerance of two dominant Antarctic planktic copepods (Calanus propinquus and Metridia gerlachei) was tested over a range from 34 to 85 PSU and compared with that of sympagic turbellarians. The copepods survived only at a salinity of 34, higher salinities causing death within days. The turbellarians survived at salinities up to 75. The data imply that C. propinquus and M. gerlachei will not survive incorporation into newly forming sea ice because of the increasing brine salinity in new ice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003000050288
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  • 8
    Electronic Resource
    Electronic Resource
    Crushing of axially compressed steel tubes filled with aluminium foam (1997)
    Springer
    Acta mechanica 125 (1997), S. 93-105 
    Details
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary This study, with the emphasis on experiments, investigates the applicability of aluminium foam as filler material in tubes made of mild steel having square or circular cross sections, which are crushed axially at low loading velocities. In addition to the experiments finite element studies are performed to simulate the crushing behaviour of the tested square tubes, were a crushable foam material model is shown to be suitable for describing the inelastic response of aluminium foam with respect to the considered problems. The experimental results for the square tubes reveal efficiency improvements with respect to energy absorption of up to 60%, resulting from changed buckling modes of the tubes and energy dissipation during the compression of the foam material itself. The principal features as well as the changes of the crushing process due to filling can also be studied by the numerical simulations. A global failure mechanism due to a high foam density can be observed for filled circular tubes. Aluminium foam is shown to be a suitable material for filling thin-walled tubular steel structures, holding the potential of enhancing the energy absorption capacity considerably, provided the plastic buckling remains characterized by local modes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01177301
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of extremely low frequency electromagnetic field (EMF) on collagen type I mRNA expression and extracellular matrix synthesis of human osteoblastic cells (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 19 (1998), S. 222-231 
    Details
    ISSN: 0197-8462
    Keywords: electromagnetic field ; myositis ossificans ; osteoblastic cells ; in vitro ; 3-D cell culture ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Human osteoblastic cells were grown in a three-dimensional (3-D) cell culture model and used to test the effects of a 20 Hz sinusoidal electromagnetic field (EMF; 6 mT and 113 mV/cm max) on collagen type I mRNA expression and extracellular matrix formation in comparison with the effects of growth factors. The cells were isolated from trabecular bone of a healthy individual (HO-197) and from a patient presenting with myositis ossificans (MO-192) and grown in a collagenous sponge-like substrate. Maximal enhancement of collagen type I expression after EMF treatment was 3.7-fold in HO-197 cells and 5.4-fold in MO-192 cells. Similar enhancement was found after transforming growth factor-β (TGF-β) and insulin-like growth factor-I (IGF-I) treatment. Combined treatment of the cells with EMF and the two growth factors TGF-β and IGF-I did not act synergistically. MO-192 cells produced an osteoblast-characteristic extracellular matrix containing collagen type I, alkaline phosphatase, and osteocalcin, together with collagen type III, TP-1, and TP-3, two epitopes of an osteoblastic differentiation marker. The data suggest that the effects of EMFs on osteoblastic differentiation are comparable to those of TGF-β and IGF-I. We conclude that EMF effects in the treatment of skeletal disorders and in orthopedic adjuvant therapy are mediated via enhancement of collagen type I mRNA expression, which may lead to extensive extracellular matrix synthesis. Bioelectromagnetics 19:222-231, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
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    Arctic spring awakening – Steering principles behind the phenology of vernal ice algal blooms (2015)
    Elsevier
    Details
    Publication Date: 2015-12-01
    Print ISSN: 0079-6611
    Electronic ISSN: 1873-4472
    Topics: Geosciences , Physics
    Published by Elsevier
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