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  • 1
    Electronic Resource
    Electronic Resource
    Sexual isolation between Drosophila melanogaster females and D. simulans males: sexual maturation of males (1989)
    Springer
    Entomologia experimentalis et applicata 52 (1989), S. 159-166 
    Details
    ISSN: 1570-7458
    Keywords: Sexual isolation ; sexual maturation ; Drosophila melanogaster ; Drosophila simulans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Des lignées isofemelles de D. simulans ont été examinées pour déterminer l'âge de la maturité sexuelle des mâles avec des femelles conspécifiques et pour établir la fréquence de l'hybridation avec des femelles de D. melanogaster. Les mâles ont commencé à être sexuellement mûrs le premier jour après l'émergence, mais leur aptitude à la copulation a augmenté lentement pendant le jour suivant. Les estimations, tant de l'âge du début de la maturation sexuelle que de l'âge du passage de mâle immature à mâle sexuellement mûr dépendaient étroitement des génotypes des femelles utilisées dans les expériences. Il n'y avait pas de différences nettes entre les lignées de mâles. Par contre, des différences dans les fréquences d'hybridation avec les femelles de D. melanogaster ont été observées. De ces résultats, on peut conclure que les différences dans la réussite des hybridations des lignées de mâles de D. simulans n'étaient pas dues à la vitesse de maturation sexuelle des mâles.
    Notes: Abstract Isofemale lines of D. simulans were examined to determine the age of sexual maturity of males with conspecific females, and for the frequency of hybridization with D. melanogaster females. Males started to mature sexually on the first day after eclosion but their ability to mate slowly increased during the following day. The estimates of both the age sexual maturation started and the switch from immature to mature males were strongly dependent on the female genotypes used in the tests. No clear differences in speed of maturation were apparent between male lines. In contrast, differences in frequency of hybridization with D. melanogaster females did occur. From the above results it is concluded that the differential hybridization success of male D. simulans lines is not related to the speed at which males mature sexually.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00163250
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  • 2
    Electronic Resource
    Electronic Resource
    The effects of phosphonates on experimental osteoporosis (1971)
    Springer
    Calcified tissue international 8 (1971), S. 114-120 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Phosphonates ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'effet d'un diphosphonate, EHDP est étudié dans deux systèmes éxpérimentaux chez le rat: une ostéoporose par immobilisation locale et une ostéoporose générale induite par la cortisone. EHDP est susceptible de prévenir la perte osseuse localisée, induite par l'immobilisation chirurgicale de la patte arrière gauche, mais est inefficace à empêcher la perte osseuse par voie générale induite par l'administration de cortisone. L'action majeure de l'EHDP est la production de grandes quantités d'ostéoide: il a peu d'effet sur la résorption osseuse. Le manque de résultats constants dans les deux systèmes suggère que les troubles osseux d'étiologie générale ne peuvent être étudiés par atrophie osseuse locale.
    Abstract: Zusammenfassung Die Wirkung eines Diphosphonates (EHDP) wurde mit zwei verschiedenen Versuchsanordnungen an Ratten untersucht: lokale Immobilisationsosteoporose und generalisierte, durch Cortison hervorgerufene Osteoporose. EHDP konnte den lokalen Knochenschwund verhindern, der durch die chirurgische Immobilisierung des linken Hinterbeines entstand; es verhinderte jedoch den generalisierten, durch Cortisonverabreichung hervorgerufenen Knochenschwund nicht. Die hervorstechendste Wirkung von EHDP ist die Bildung von großen Osteoidmengen; es scheint auf die Knochenresorption nur einen kleinen Einfluß zu haben. Der Mangel an gültigen Befunden bei beiden Versuchsanordnungen läßt darauf schiließen, daß aus einer lokalen Knochenatrophie nicht auf eine durch generalisierten Knochenschwund charakterisierte Erkrankung extrapoliert werden kann.
    Notes: Abstract The effect of a diphosphonate, EHDP, was studied in two experimental models in the rat: local immobilization osteoporosis and systemic cortisone-induced osteoporosis. EHDP was able to prevent the local bone loss brought about by surgical immobilization of the left hind limb, but was ineffective in preventing the systemic bone loss produced by cortisone administration. The most prevalent action of EHDP is the production of large amounts of osteoid; it seems to have little effect on bone resorption. The lack of consistent findings in both models suggests that systemic bone-losing disorders cannot be extrapolated from local bone atrophy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010128
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  • 3
    Electronic Resource
    Electronic Resource
    Soil Carbon Pools under Conventional and No-Tillage Systems in the Argentine Rolling Pampa (1998)
    Springer
    Semigroup forum 90 (1998), S. 138-143 
    Details
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: -1 ) on C inputs and outputs of a Typic Argiudoll and on organic C level and density fractions were studied in a field experiment at the end of 15yr under a corn (Zea mays L.)-wheat (Triticum aestivum L.)-soybean [Glycine max (L.) Merr.] rotation. Microbial biomass and the rate of organic C mineralization during laboratory incubations were also determined. Nitrogen fertilization had no significant influence on C emission in the field, soil organic matter level or microbial biomass and activity. The annual C budget was negative under both tillage systems, but no-tillage lost about 0.7 to 1.5 Mg ha-1yr-1 more C than did plow tillage. Carbon in the medium-density fraction (density=1.6-2.0 g mL-1) of the 0- to 20-cm soil layer was 30% higher (P≤0.05) under no-tillage. Light (density〈1.6 g mL-1) and heavy (density〉2.0 g mL-1) organic fractions, total C, and microbial biomass and activity in the 0- to 20-cm layer were not different in no-tilled and plowed soils, despite different patterns of distribution with depth. The rates of organic C mineralization during laboratory incubations were the same for both tillage systems. We propose that, after an accumulation phase, soil under no-tillage loses higher amounts of CO2--C than under plowing. The use of no-tillage would not significantly affect soil organic matter pools of the region in situations with low erosion losses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/
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  • 4
    Electronic Resource
    Electronic Resource
    Comparative spatial distribution, size, biomass and growth rate of two varieties of bracken fern (Pteridium aquilinum L. Kuhn) in a neotropical montane habitat (1996)
    Springer
    Plant ecology 125 (1996), S. 137-147 
    Details
    ISSN: 1573-5052
    Keywords: Bracken fern ; Density ; Fire cycle ; Pteridium-aquilinum-subsp.-caudatum ; var.-caudatum ; var.-arachnoideum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A comparative field study of caudatum and arachnoideum, the two Pteridium aquilinum varieties of the caudatum subspecies known to grow in the neotropics, was performed in a montane savanna habitat of the Venezuelan Andes that was affected by wildfire. Frond size, ramet density and spatial distribution, blade and rhizome biomass, and frond elongation and expansion rates were measured in separate, isolated stands each containing only one bracken variety and covering approximately the same area (∼540 m2). In addition to clearly discernible morphological differences, caudatum and arachnoideum were found to possess distinct features: caudatum tends to develop open stands of relatively shorter blades of 76.6±0.89 cm (μ±SE) of rachis length and lower ramet density (1.6 fronds m-2, max.=7 fronds m-2) whereas arachnoideum grows into longer, more expanded fronds 124±1.6 cm tall and significantly higher ramet density (5.1 fronds/m2, max.=14.6 fronds m-2). The sum of aerial and underground biomass was found to be notably larger for arachnoideum (8522±614 Kg/ha) than for caudatum (1929±131 Kg ha-1) in stands growing under the same habitat conditions. Therefore the spatial distribution of arachnoideum appeared considerably more compact than that of caudatum. Blade growth rates and development time were also very different. Newly emerged caudatum croziers developed into mature blades within 42 to 48 days following an inverse exponential curve whereas arachnoideum blades required 70 to 75 days to reach maturity following a linear development. All the above dissimilarities are interpreted as the hitherto unreported indication of diverging growth strategies of two cohabitant bracken varieties following fire.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00044647
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  • 5
    Electronic Resource
    Electronic Resource
    Ontogenic variation of biologically active metabolites ofPteridium aquilinum (L. Kuhn) pterosins A and B, and ptaquiloside in a bracken population of the tropical andes (1992)
    Springer
    Journal of chemical ecology 18 (1992), S. 1405-1420 
    Details
    ISSN: 1573-1561
    Keywords: Bracken fern ; Pteridium aquilinum var.Caudatum ; tropics ; ptaquiloside ; pterosin A ; pterosin B ; quantitation ; HPLC ; blade growth ; semiochemicals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A negative correlation has been found between the amounts of pterosins A and B and ptaquiloside per biomass unit, and the growth stage of the blade of bracken. Their concentration decreased progressively from the crozierto the mature frond, where it attained less than 5% of the initial value. The growth was measured following the total blade length, its height, moisture content, and time of emergence from the soil surface. Quantitation of these compounds was achieved by HPLC using a water extraction, methylene chloride treatment, and silica gel microcolumn cleanup sequence. Pterosins were unevenly distributed in the blade, whereas ptaquiloside maintained a constant concentration throughout. Rhizomes contained only minor amounts of these compounds. Their possible role as semiochemicals in bracken is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00994365
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  • 6
    Electronic Resource
    Electronic Resource
    Linear pseudosystolic array for partitioned matrix algorithms (1991)
    Springer
    The journal of VLSI signal processing systems for signal, image, and video technology 3 (1991), S. 201-214 
    Details
    ISSN: 1573-109X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract We describe a class-specific linear pseudosystolic array, withK processing elements, suitable for partitioned execution of matrix algorithms. This array achieves high efficiency, exploits pipelining within cells in a simple manner, has off-cells communication rate lower than computation rate, a small storage inside each cell (whose size is independent of the size of problems), and external storage. This array has been derived from the application of the multimesh graph (MMG) method to a large class of matrix algorithms. Processing elements (cells) use the decoupled access/execute model of computation, which requires two programs in each cell: one controlling the execution of operations and the other the data transfers. All storage modules in the array are accessed as FIFO queues, without the need for addressing mechanisms. We describe the proposed instruction set, which includes single-instruction loops with no overhead, and block-loops with just one extra instruction. Moreover, cells can nest up to three loops with no added overhead. These features are needed for mapping algorithms with the MMG method. Mapping onto this array is illustrated using the LU-decomposition algorithm, and results obtained with other algorithms are also given. Estimates of performance indicate that it is possible to achieve over 85% efficiency, with low requirements in communication bandwidth and storage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00925831
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  • 7
    Electronic Resource
    Electronic Resource
    A new bioassay for testing plant extracts and pure compounds using red flour beetleTribolium castaneum Herbst (1994)
    Springer
    Journal of chemical ecology 20 (1994), S. 1161-1177 
    Details
    ISSN: 1573-1561
    Keywords: Bioassay ; red flour beetle ; Tribolium castaneum ; Coleoptera ; Tenebrionidae ; ECI ; Minthostachis mollis ; Melaleuca quinquenervia ; Sapindus saponaria ; α-pinene ; β-pinene ; eugenol ; kaurenic acid ; sparteine ; phagodepression ; phagostimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We designed a new bioassay to test plant extract activity against stored product pests. Plant compounds were added to feed disks composed of wheat flour and yeast and fed to the red flour bettle (Tribolium castaneum). By measuring insect mass, disk mass, and insect mortality over time it was possible to calculate a phagodepression index, an antifeedant index, the amount of treatment chemical ingested by the beetles, the mortality rate, and the efficiency of conversion of ingested food. The assay was performed for 60 hr to allow for possible habituation effects and to discriminate between phagodeterrency and physiological stress caused by treatments. α- and β-Pinene, eugenol, kaurenic acid, sparteine, essential oils ofMinthostachis mollis andMelaleuca quinquenervia, and extracts ofSapindus saponaria were tested. Using this assay we detected the presence of both phagodepressant and phagostimulant compounds inS. saponaria extracts, and we quantified the pronounced effects of sparteine onT. castaneum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02059751
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  • 8
    Electronic Resource
    Electronic Resource
    Modeling Synergistic and Antagonistic Interactions in Xenobiotic Compounds (2000)
    Springer
    Journal of chemical ecology 26 (2000), S. 513-531 
    Details
    ISSN: 1573-1561
    Keywords: phytometabolites ; synergism ; antagonism ; mathematical modeling ; cotoxicity ; coactivity coefficient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Over time, synergistic/antagonistic interactions between pairs of compounds has been examined from a variety of viewpoints that impose difficulties in comparative studies. The increasing importance of potentiated activity in plant–organism interfaces mediated by secondary phytometabolites and also of inter- and intraspecific animal interactions, and their ecological impact in terms of increased cost effectiveness and organism fittness in the production of active compounds, demands that a standard methodology be designed to ascertain the amount of synergism/antagonism of A + [B, C, ..., Z] mixtures. Here we preface one such method, based on the comparison of theoretically predicted addition of dose–response (D/R) curves of pairs of compounds mixed in 0–100% relative proportions and constant added dosage, examined at various total dosages, with experimental results of similarly composed mixtures. It is shown that large effects in the activity prediction curves occur as a consequence of minor changes in the D/R profiles of individual compounds. These changes may lead to equivocal assessment of potentiation by application of coactivity coefficients without close examination of predicted curves. Evaluation of this method with literature from the data surveyed illustrated its potentially general application in studies of compound synergism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005425909406
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  • 9
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    Morphological divergence between wild and cultivated chaya (Cnidoscolus aconitifolius) (Mill.) I.M. Johnst (2019)
    Springer
    Details
    Publication Date: 2019-06-15
    Print ISSN: 0925-9864
    Electronic ISSN: 1573-5109
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Springer
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  • 10
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    Theoretical study of phosphorene multilayers: optical properties and small organic molecule physisorption (2017)
    Springer
    Details
    Publication Date: 2017-12-14
    Print ISSN: 0022-2461
    Electronic ISSN: 1573-4803
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Springer
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