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231.
IntroductionThenotionofsustainabledevelopmentwasproposedintheWorldConservationStrategy(IUCN,1980).Itispointedoutthattheconservationandthesustainabledevelopmentaremutuallydependentandtheyshouldbeintegrated,wheretheconservationmeansthemanagementofhuman… 相似文献
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Vivid motion illusions created by some Op art paintings are at the centre of a lively scientific debate about possible mechanisms that might underlie these phenomena. Here we review emerging evidence from a new approach that combines perceptual judgements of the illusion and observations of eye movements with simulations of the induced optic flow. This work suggests that the small involuntary saccades which participants make when viewing such Op art patterns would generate an incoherent distribution of motion signals that resemble the perceptual effects experienced by the observers. The combined experimental and computational evidence supports the view that the illusion is indeed caused by involuntary image displacements picked up by low-level motion detectors, and further suggests that coherent motion signals are crucial to perceive a stable world. 相似文献
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Joana F. M. F. Cardoso Johannes IJ. Witte Henk W. van der Veer 《Marine Biology》2007,152(6):1271-1282
In estuarine areas, bivalve species can be found in a variety of environments, where they experience large differences in
environmental conditions. In the present paper, the importance of different habitats (intertidal, subtidal and adjacent coastal
waters) for the persistence of the population was evaluated for the bivalve Macoma balthica (L.) in the western Dutch Wadden Sea estuary. Intra-specific variation in growth and reproductive output were followed during
the year and related to local abiotic conditions. Significant differences in growth and reproductive investment were found
between locations. Young individuals were mostly found in the intertidal area, where growth in terms of somatic mass was good.
These areas were not favourable for adult individuals, since growth in shell length was low and many individuals did not reproduce.
In the subtidal, where the highest densities were found, somatic and gonadal mass indices were low. Coastal areas had the
lowest densities and showed high growth in terms of shell length and body mass. The habitat with the highest reproductive
effort per individual was not the most important habitat in terms of reproductive output due to differences in density and
in size of the habitat type. For M. balthica, the subtidal habitat contributed the most to the reproductive output of the western Dutch Wadden Sea population although
the highest reproductive output per individual was in the coastal area. 相似文献
239.
On an 85 km stretch of coastline along the western and northwestern edge of North West Cape Peninsula, Western Australia, are numerous beaches used for nesting by the green turtle Chelonia mydas. Many other beaches in the area are not so used. Nesting beaches displayed three characteristics that distinguished them from non-nesting beaches: the salinity of the sand moisture at nesting depth was lower, the salt content of surface sand was lower, and the beaches were sheltered from prevailing winds. Several beaches on which turtles did not nest exhibited these characteristics, but possessed sand platforms of reduced elevation above sea level. These observations are discussed in relation to the question of what cues green turtles use in selecting nesting beaches. 相似文献
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