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  • 1
    Electronic Resource
    Electronic Resource
    Factors affecting the seed-setting success of Dryas octopetala in front of Brøggerbreen (Brøgger Glacier) in the high Arctic, Ny-Ålesund, Svalbard (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 18 (1999), S. 0 
    Details
    ISSN: 1751-8369
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Geosciences
    Notes: To determine the factors restricting plant reproduction in front of a glacier, the gender expression and seed production of Dryas octopetala L. (Rosaceae) were observed, as well as the grazing pattern of reindeer on flowers, near Brøggerbreen (Brøgger Glacier), which is near Ny-Ålesund (78° 55'N, 11° 56'E), Svalbard. Three hundred shoots with flowers and flower buds were randomly tagged in early July 1996. Between then and the end of flowering in late July, 100 (33%) flowers and buds were grazed by reindeer. Out of the surviving flowers, 145 (76%) shoots had hermaphrodite flowers, while 45 (24%) shoots had male flowers without a developed gynocium. Male flowers, which appeared later than hermaphrodite flowers in the population, were significantly smaller than hermaphrodite flowers in dry weight. In the hermaphrodite flowers, moreover, smaller flowers showed lower dry-weight allocation to the gynoecium as compared to larger flowers. During the observation, hermaphrodite flowers did not produce any developed seeds under a natural condition (0% seed-set). Cross-pollinated flowers showed 8% seed-set. On the other hand, flowers which were artificially warmed in small greenhouses during the flowering period showed 60% seed-set, regardless of cross-pollination or autodeposition of pollen from anthers to stigma (self-pollination). Thus, it was found that grazing, gender variation in relation to the length of the growing season and the flower size, and - in the floweriing period - low temperature rather than pollinator limitation strongly affected the seed production of D. octopetala in the population studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1751-8369.1999.tb00302.x
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  • 2
    Electronic Resource
    Electronic Resource
    Fundamental Properties of 10 Gbit/s Coherent Optical Code Division Multiplexing: Experiment (1998)
    Springer
    Optical review 5 (1998), S. 31-38 
    Details
    ISSN: 1349-9432
    Keywords: optical communication ; code division multiplexing ; optical bipolar code ; optical phase ; interference ; correlation ; coherence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Coherent optical code division multiplexing is a novel method using the phase of optical pulse as the bipolar code for future fiber-optic communication networks. Some optical bipolar codes with a repetition frequency over 10 GHz are generated experimentally and their fundamental properties are elucidated. The key features of the method, auto- and cross-correlation of these codes, are shown experimentally and compared with the theoretical results. Interference between two optical narrow pulses with high repetition frequency is investigated experimentally under various conditions of optical phase and wavelength as the basis of the method. A guaranty of realization of the technique is shown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10043-998-0031-y
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  • 3
    Electronic Resource
    Electronic Resource
    Bispectrum Analysis of One-Dimensional Regular Fractals with Additive Random Noise (1994)
    Springer
    Optical review 1 (1994), S. 51-54 
    Details
    ISSN: 1349-9432
    Keywords: bispectrum ; power spectrum ; fractal ; Cantor set ; random noise ; band-average ; power law
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The bispectrum of the Cantor set that is a typical regular fractal is calculated and its fractalities are shown. A relation between the bispectrum and the fractal dimension of the object is elucidated. Effects of additive random noise on the scaling property of the bispectrum are compared with those of the corresponding power spectrum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10043-994-0051-1
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  • 4
    Electronic Resource
    Electronic Resource
    Dwarf bamboos affect the regeneration of zoochorous trees by providing habitats to acorn-feeding rodents (1993)
    Springer
    Oecologia 94 (1993), S. 403-407 
    Details
    ISSN: 1432-1939
    Keywords: Dwarf bamboo ; Regeneration ; Sasa ; Shade-tolerance ; Zoochore
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of dwarf bamboos (Sasa spp.) on the regeneration of trees in a natural hardwood forest were studied by analysing the spatial dispersion of seedlings and saplings of anemochores (Acer palmatum var. matsumurae, Fraxinus lanuginosa, and Carpinus laxiflora) and zoochores (Quercus mongolica var. grosseserrata and Q. serrata). Relative photosynthetic photon flux density at 10 cm above ground was significantly correlated with the coverage of dwarf bamboos (r=0.661, P〈0.001). Seedlings were abundant and were randomly distributed in the anemochores, other than the shade-intolerant species C. laxiflora which was significantly more sparse in sites with dense Sasa than in sites where Sasa was rare. Distribution of saplings was also random in the shadetolerant anemochores A. palmatum var. matsumurae and F. lanuginosa but aggregated in sites with sparse Sasa in the shade-intolerant anemochore C. laxiflora. In contrast to the anemochores, seedlings of zoochores were very few and were distributed in sites with sparse Sasa. Saplings were also aggregated and negatively correlated with Sasa cover in the shade-intolerant species Q. serrata and the tolerant species Q. mongolica var. grosseserrata. The acorns put on the forest floor in a site with dense Sasa were quickly removed by small rodents such as Apodemus speciosus and A. argenteus. Trap census of rodents revealed that those mammals prefer the dense Sasa habitat to the sparse Sasa habitat. This suggests that the dwarf bamboos strongly affect the regeneration of zoochorous trees not only by shading the seedlings but also by providing habitats to acorn-feeding small mammals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317116
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of herbivore-bearing adult trees of the oak Quercus crispula on the survival of their seedlings (2000)
    Springer
    Ecological research 15 (2000), S. 219-227 
    Details
    ISSN: 1440-1703
    Keywords: herbivory ; lepidopteran larvae ; oak ; polyphagy ; Quercus ; reciprocal replacement ; seedling survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: The acorn-producing oak Quercus crispula Blume is shade-tolerant and its seedlings were found to be underdispersed on the forest floor, forming seedling aggregations near fertile canopy trees. However, 84.4% of the seedlings were dead within 2 years, with the highest mortality near the adult canopy trees of Q. crispula. This was mostly due to the high levels of herbivory by lepidopteran larvae. The most serious damage was caused by spring consumers, which fed on the leaves of canopy trees in June and, when the food quality of the leaves declined, fell down to the forest floor to consume the juveniles, including the seedlings. Contrary to the expectation of the herbivore–host arms race theory, most of the herbivores were polyphagous. The most dominant spring consumer Telorta edentata (Leech) was also polyphagous, and its distribution on the forest floor showed a high level of association with the distribution of dead oak seedlings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1440-1703.2000.00343.x
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  • 6
    Electronic Resource
    Electronic Resource
    Ecological significance of the aerial seed pool of a desert lignified annual, Blepharis sindica (Acanthaceae) (1998)
    Springer
    Plant ecology 135 (1998), S. 177-184 
    Details
    ISSN: 1573-5052
    Keywords: Aerial seed pool ; Blepharis sindica ; Desert ; Discontinuous seed release ; Germination ; Lignified annual ; Seed predation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Reproductive traits of a lignified annual plant, Blepharis sindica were studied in relation to the formation of an 'aerial seed pool' on dead plants in an arid grassland in the Thar Desert of northwestern India. The dead plants remained standing on the soil surface and retained fruits for more than one year. Aerial seed pools developed about 6 cm above the ground. There were no seed pools on or below the ground surface. Only 5.7% of seeds died on dead plants because of insect predation or fungi infection during one year. Seed release was cued by rainfall, and a fraction of seeds on the aerial seed pools was released in each rainfall event. After 13 rainfall events during the monsoon season, 25% of seeds was still retained on the plants. Seed predation on the ground surface was intensive; all cones placed on the soil surface were removed within four days, and 97% of fruits were removed within 10 days. Fifty percent of seeds germinated within 3.5 h, and there were no differences in viability and time required for germination between first year seeds and older seeds. The results indicate that the aerial seed-holding on dead plants is an available way to avoid seed predation in harsh desert environments where seed predation is intense and favorable periods for growth are temporally limited and unpredictable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009713512472
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  • 7
    Electronic Resource
    Electronic Resource
    Impact of overgrazing on seed predation by rodents in the Thar desert, northwestern India (1995)
    Springer
    Ecological research 10 (1995), S. 217-221 
    Details
    ISSN: 1440-1703
    Keywords: desert rodents ; overgrazing ; seed predation ; succession ; Thar desert
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We compared the vegetation structure, rodent density and seed loss rate between protected and disturbed sites affected from grazing by cattle, goats and sheep, in the Thar desert of India. A perennial tussocky grassLasiurus sindicus Hent. was largely dominant in the protected site, whileL. sindicus was rare and replaced by undershrub speciesAerva pseudotomentosa Blatt. & Halb. andCrotalaria burbira Buch.-Ham. in the overgrazed site. In the grazed site, plant coverage was low, but the density of rodent burrows and the frequency of rodent captures were significantly high as compared to the protected site. Corresponding with the density of desert rodents, seed predation was significantly higher in the grazed site than in the protected site. These results suggest that overgrazing by large mammals has strong effects on plant succession by altering not only the species composition and abundance of plant community, but also the habitat suitability for seed-eating rodents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02347944
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  • 8
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    Unknown
    Modeling gas hydrate petroleum systems of the Pleistocene turbiditic sedimentary sequences of the Daini-Atsumi area, eastern Nankai Trough, Japan (2016)
    Society of Exploration Geophysicists
    In:  Interpretation, 4 (1). SA95-SA111.
    Details
    Publication Date: 2019-02-01
    Description: We have performed 2D and 3D gas hydrate (GH) petroleum systems modeling for the Pleistocene turbiditic sedimentary sequences distributed in the Daini-Atsumi area in the eastern Nankai Trough to understand the accumulation mechanisms and their spatial distribution related to geologic and geochemical processes. High-resolution seismic facies analysis and interpretations were used to define facies distributions in the models. We have created a new biogenic methane generation model based on the biomarker analysis using core samples and incorporated it into our model. Our 2D models were built and simulated to confirm the parameters to be used for 3D modeling. Global sea level changes and paleogeometry estimated from 3D structural restoration results were taken into account to determine the paleowater depth of the deposited sedimentary sequences. Pressure and temperature distributions were modeled because they are the basic factors that control the GH stability zone. Our 2D modeling results suggested that the setting of biogenic methane generation depth is one of the most important controlling factors for GH accumulation in the Nankai Trough, which may be related to the timing of methane upward migration (expulsion) and methane solution process in pore water. Our 3D modeling results suggested that the distribution of sandy sediments and the formation dip direction are important controlling factors in the accumulation of GHs. We also found that the simulated amount of GH accumulation from the petroleum systems modeling compares well with independent estimations using 3D seismic and well data. This suggests that the model constructed in this study is valid for this GH system evaluation and that this type of evaluation can be useful as a supplemental approach to resource assessment.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1190/INT-2015-0022.1
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    OceanRep: Article in a Scientific Journal - peer-reviewed
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