Trends in integrating communication functionality to complement existing services by next-generation energy-saving white LED lighting are reviewed. Challenges at component and system level are discussed to enable visible light communication a practical service provision infrastructure. (2 pages)
Abstract We studied seasonal variation in density and species richness of seeds in the 0–10 cm soil depth layer in primary, secondary and pine forests, and in shrubland and grassland in the Shilin Stone Forest Geographical Park, Yunnan, SW China. Soil samples were collected four times during the year at 3-month intervals. Seeds from 119 species were identified by germination tests in the soil samples. Density and species richness of seeds of herbaceous plants were greater than woody plants at all five sites throughout the year. Sampling time and site differences had significant effects on the mean number of species and on seed-bank density. Mean number of species per sample increased from February, reached the highest value in May, decreased to the lowest value in August and then increased in November. An exception was in the primary forest, where the highest number of species was found in February. Mean seed-bank density peaked in May at all five sites, and no significant differences were found between densities in February, November and August, except for the primary forest. The peak in seed-bank density in May might be due to dispersal of new seeds of spring-fruiting species, combined with persistence of seeds dispersed in previous years. This seasonal variation of individual species was due primarily to differences in species phenology rather than to differences between sites. Four seasonal seed-bank strategies were identified: two transient and two persistent. At all sites, similar numbers of seeds of herbaceous species were found between seasons, but the number of species of trees and shrubs decreased in August.
An analysis on karst environment change processes in the North eastern karst areas of Italy was made in the paper. Karst environment there experienced serious environmental degradation and gradual restoration in past years. Karst environmental degradation there was caused by over grazing and over cultivating through cleaning forest as well as firewood and timber industry. The war also contributed to the degradation. Restoration of the degraded environment succeeded since the end of the second World war although works for reforestation began in the 12th century. The successful process of environmental restoration and control in the region was an integral one, which involved multi value exploitation, adjustment of regional social economic structures, realization of urbanization, improvement of populotion quality, and provision of new eaploymert opportunities for the locals. The significance of the experience of karst environment restoration of north easernt Italy for Chinese karst environment control was also discussed in the paper.
Anelloviruses comprise a group of non-enveloped circular single-stranded DNA viruses with genomes of 2–4 kb. Anelloviruses were first reported in 1997 in a Japanese patient with post-transfusion he...
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