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  • 1
    Electronic Resource
    Electronic Resource
    A computational model of ameboid deformation and locomotion (1998)
    Springer
    European biophysics journal 27 (1998), S. 532-539 
    Details
    ISSN: 1432-1017
    Keywords: Key words Ameboid deformation ; Ameboid locomotion ; Computational model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Traditional continuum models of ameboid deformation and locomotion are limited by the computational difficulties intrinsic in free boundary conditions. A new model using the immersed boundary method overcomes these difficulties by representing the cell as a force field immersed in fluid domain. The forces can be derived from a direct mechanical interpretation of such cell components as the cell membrane, the actin cortex, and the transmembrane adhesions between the cytoskeleton and the substratum. The numerical cytoskeleton, modeled as a dynamic network of immersed springs, is able to qualitatively model the passive mechanical behavior of a shear-thinning viscoelastic fluid (Bottino 1997). The same network is used to generate active protrusive and contractile forces. When coordinated with the attachment-detachment cycle of the cell's adhesions to the substratum, these forces produce directed locomotion of the model ameba. With this model it is possible to study the effects of altering the numerical parameters upon the motility of the model cell in a manner suggestive of genetic deletion experiments. In the context of this ameboid cell model and its numerical implementation, simulations involving multicellular interaction, detailed internal signaling, and complex substrate geometries are tractable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002490050163
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  • 2
    Electronic Resource
    Electronic Resource
    The effects of desmethylimipramine on the pharmacological actions of alpha methyldopa in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 75-80 
    Details
    ISSN: 1432-1041
    Keywords: methyldopa ; hypotension ; tricyclic antidepressants ; drug interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of pretreatment with the tricyclic antidepressant desmethylimipramine (DMI) 75 mg daily for 3 days on the action of oral methyldopa 750 mg was investigated in a double blind crossover design in volunteers. DMI pretreatment caused a small but not significant increase in supine systolic and diastolic blood pressure and heart rate. However, the effects of methyldopa on lying and standing blood pressure and heart rate were not markedly altered by pretreatment. In particular, the fall in standing blood pressure after methyldopa was present with and without DMI and the sedative action of methyldopa was similar. DMI alone reduced saliva production. No evidence was found that tricyclic antidepressant drugs significantly modify the hypotensive effect of methyldopa in man.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00563110
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  • 3
    Electronic Resource
    Electronic Resource
    Frame Rate and Viseme Analysis for Multimedia Applications to Assist Speechreading (1998)
    Springer
    The journal of VLSI signal processing systems for signal, image, and video technology 20 (1998), S. 7-23 
    Details
    ISSN: 1573-109X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Current video conference and phone systems do not provide the necessary temporal resolution and motion for speechreading. In this paper the perceptual boundaries which effect speechreading performance are investigated. Analysis of the relationships between viseme groupings, accuracy of viseme recognition and presentation frame rate is presented based on the results of subject testing. Results reveal a minimum frame rate of 10 frames per second (fps) for distinguishing viseme groupings. Confusion analysis results demonstrate the importance of the tongue and teeth oral features for speechreading. These results are critical to the design of speech-assisted video systems to enhance speechreading for individuals with impaired hearing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008062122135
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  • 4
    Electronic Resource
    Electronic Resource
    Liquidus phase relationships on the join anorthiteforsterite-quartz at 20 kbar with applications to basalt petrogenesis and igneous sapphirine (1990)
    Springer
    Contributions to mineralogy and petrology 104 (1990), S. 735-742 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Liquidus phase relationships determined on the join anorthite-forsterite-quartz at 20 kbar show primary phase fields for quartz (q), forsterite (fo), enstatite (en), spinel (sp), anorthite (an), sapphirine (sa), and corundum (cor). Increasing pressure causes (1) thefo andan primary phase fields to contract, (2) theen, q, andcor fields to expand, (3) thefo-en boundary line to move away from the Q apex, (4) theen-q boundary line to move also away from the Q apex but by a smaller amount, and (5) a primary phase field forsa to appear at a pressure between 10 and 20 kbar. Seven liquidus piercing points at 20 kbar have been located as follows: Crystalline phases Liquid composition (wt %) Temperature (°C) sp+sa+cor An81Fo17Q2 1575 fo+en+sp An52Fo39Q9 1540 en+sp+sa An59Fo31Q10 1490 sa+an+cor An70Fo15Q15 1430 an+q+cor An66Fo7Q27 1410 sa+an+en An62Fo18Q20 1400 an+en+q An59Fo15Q26 1380 It is concluded that (1) the shift of thefo-en boundary line away from the quartz apex with pressure confirms many other studies showing that melts generated from peridotite source rocks decrease in silica content as pressure increases; (2) even though plagioclase is not a stable phase in peridotite source rocks at pressures above about 10 kbar, it can crystallize from mafic magmas at pressures at least up to 20 kbar; (3) sapphirine crystallizes from mafic magmas at high pressures and may be important in the construction of petrogenetic models based on trace element considerations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01167290
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  • 5
    Electronic Resource
    Electronic Resource
    A novel repetitive sequence associated with the centromeric regions of Arabidopsis thaliana chromosomes (1996)
    Springer
    Molecular genetics and genomics 253 (1996), S. 247-252 
    Details
    ISSN: 1617-4623
    Keywords: Key words Middle repetitive sequence ; Arabidopsis ; In situ hybridization ; Centromere ; Physical mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The middle repetitive fraction of the Arabidopsis genome has been relatively poorly characterized. We describe here a novel repetitive sequence cloned in the plasmid mi167, and present in ∼90 copies in the genome of Arabidopsis thaliana ecotype Columbia. Hybridization analysis to physically mapped YAC clones representing Arabidopsis chromosome 4 revealed four mi167-hybridizing loci, all clustered near the centromere. No other loci were detected on YAC clones covering chromosome 4. In situ hybridisation experiments to Arabidopsis chromosome spreads showed that mi167-hybridizing sequences are clustered at the centromeric heterochromatin of all five chromosomes; on two chromosomes the hybridization appeared to be localised on one arm. Additional mi167-hybridizing loci were detected, one of which was adjacent to a non-centromeric, heterochromatic region. This work supports the idea that the majority of middle repetitive DNA in the Arabidopsis genome is clustered. It also adds to our understanding of the organization of the centromere of Arabidopsis chromosome 4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050319
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  • 6
    Electronic Resource
    Electronic Resource
    Carbonatitic melts along the solidus of model lherzolite in the system CaO-MgO-Al2O3-SiO2-CO2 from 3 to 7 GPa (1998)
    Springer
    Contributions to mineralogy and petrology 131 (1998), S. 123-135 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract We have experimentally determined the solidus position of model lherzolite in the system CaO-MgO-Al2O3-SiO2-CO2 (CMAS.CO2) from 3 to 7 GPa by locating isobaric invariant points where liquid coexists with olivine, orthopyroxene, clinopyroxene, garnet and carbonate. The intersection of two subsolidus reactions at the solidus involving carbonate generates two invariant points, I1A and I2A, which mark the transition from CO2-bearing to dolomite-bearing and dolomite-bearing to magnesite-bearing lherzolite respectively. In CMAS.CO2, we find I1A at 2.6 GPa/1230 °C and I2A at 4.8 GPa/1320 °C. The variation of all phase compositions along the solidus has also been determined. In the pressure range investigated, solidus melts are carbonatitic with SiO2 contents of 〈6 wt%, CO2 contents of ˜45 wt%, and Ca/(Ca+Mg) ratios that range from 0.59 (3 GPa) to 0.45 (7 GPa); compositionally they resemble natural magnesiocarbonatites. Volcanic magnesiocarbonatites may well be an example of the eruption of such melts directly from their mantle source region as evidenced by their diatremic style of activity and lack of associated silicate magmas. Our data in the CMAS.CO2 system show that in a carbonate-bearing mantle, solidus and near-solidus melts will be CO2-rich and silica poor. The widespread evidence for the presence of CO2 in both the oceanic and continental upper mantle implies that such low degree SiO2-poor carbonatitic melts are common in the mantle, despite the rarity of carbonatites themselves at the Earth's surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004100050383
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  • 7
    Electronic Resource
    Electronic Resource
    Genotype-by-environment interaction in genetic mapping of multiple quantitative trait loci (1995)
    Springer
    Theoretical and applied genetics 91 (1995), S. 33-37 
    Details
    ISSN: 1432-2242
    Keywords: Arabidopsis thaliana ; Flowering time ; Genotype-by-environment interaction ; Mapping ; Quantitative trait loci
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The interval mapping method is widely used for the genetic mapping of quantitative trait loci (QTLs), though true resolution of quantitative variation into QTLs is hampered with this method. Separation of QTLs is troublesome, because single-QTL is models are fitted. Further, genotype-by-environment interaction, which is of great importance in many quantitative traits, can only be approached by separately analyzing the data collected in multiple environments. Here, we demonstrate for the first time a novel analytic approach (MQM mapping) that accommodates both the mapping of multiple QTLs and genotype-by-environment interaction. MQM mapping is compared to interval mapping in the mapping of QTLs for flowering time in Arabidopsis thaliana under various photoperiod and vernalization conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220855
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  • 8
    Electronic Resource
    Electronic Resource
    Measuring returns to scale and technological change in co-operative banks: A provincial analysis of Canadian credit unions and caisses populaires (1986)
    Springer
    Empirical economics 11 (1986), S. 207-222 
    Details
    ISSN: 1435-8921
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract In Canada economies of scale in credit unions come not only from large single office arrangements but from external economies realized from belonging to central provincial credit unions. Making use of aggregate provincial time series and cross-sectional data, this study begins by employing a sequential Akaike's Information Criterion (AIC) test to select the most appropriate model. This procedure permits the isolation of economies of scale from technological change effects. For all provinces, economies of scale are discovered to be significantly different from 1, and for five of the eight provinces examined, technological change was statistically significant from zero. The larger the provincial organization, as illustrated by the Quebec caisses populaires, the higher we find estimates of returns to scale and technological change. An implication may be that both expansion and more centralization should be encouraged and that other provinces may be able to increase efficiency by imitating some of Quebec's operational and administrative practices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01977002
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  • 9
    Electronic Resource
    Electronic Resource
    Industry-region load profiles: econometric estimation based on marginal totals (1996)
    Springer
    The annals of regional science 30 (1996), S. 223-246 
    Details
    ISSN: 1432-0592
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography , Economics
    Notes: Abstract A theoretical model and a two-stage econometric estimation procedure are proposed for determining the parameters of industry-region-specific cost, input-demand, or other functions using grouped data. The model and estimation procedure are appropriate when only marginal totals or averages are available, or when data are classified by both region and industry but many cells are empty or sparsely represented. An application is reported in which load functions for the hourly input of electricity are estimated for each day of the week and each month of the year in each cell of a 31 × 7 industry-region matrix. The use of the model to simulate the sensitivity of electricity demand to regional location and weather variability is illustrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01581974
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  • 10
    Electronic Resource
    Electronic Resource
    Industry-region load profiles: econometric estimation based on marginal totals (1996)
    Springer
    The annals of regional science 30 (1996), S. 223-246 
    Details
    ISSN: 1432-0592
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography , Economics
    Notes: Abstract. A theoretical model and a two-stage econometric estimation procedure are proposed for determining the parameters of industry-region-specific cost, input-demand, or other functions using grouped data. The model and estimation procedure are appropriate when only marginal totals or averages are available, or when data are classified by both region and industry but many cells are empty or sparsely represented. An application is reported in which load functions for the hourly input of electricity are estimated for each day of the week and each month of the year in each cell of a 31×7 industry-region matrix. The use of the model to simulate the sensitivity of electricity demand to regional location and weather variability is illustrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01581974
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