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Spectral mixture analysis method was selected for mapping forest canopy closure in different periods and analyzing the dynamic changes of forest canopy closure with Landsat TM data and field sample data. And sunlit canopy, shaded canopy, sunlit background and shaded background are selected as the four components. In order to conduct the research, Anshan city is selected as the study area. We derive the forest canopy closure of Anshan city in 1990, 2000, 2006, then analysis the dynamic changes of Anshan forest canopy closure during these periods. The result shows that Anshan forest canopy closure shows a downward trend from 1995 to 2000, and shows an upward trend from 2000 to 2006. [ABSTRACT FROM PUBLISHER]

The enhanced vegetation index (EVI) was developed as a standard satellite vegetation product for the Terra and Aqua Moderate Resolution Imaging Spectroradiometers (MODIS). In this paper, MOD3A3, a global dataset with 1km spatial resolution and one month temporal resolution, was selected as the data source. The dynamic changes of vegetation EVI in China region and the seven regions of China during the period from 2001 to 2011 were studied by using maximum value method, average method and linear regression trend analysis method. Results show that: Over the past 11 years, the change of China Annual EVI was insignificant. The variation of mean EVI of different regions was obvious. Trend analysis shows that vegetation EVI in China had an increasing trend from 2001 to 2011. [ABSTRACT FROM PUBLISHER]

This paper rejects the implicit assumption in migration literature that migrant networks simply "come" with migrants and remain an exogenous variable to the migration process, more-or-less unchanged. By treating network relationship not as one-dimensional connections but as bundles of obligations and claims, this paper suggests that migrants actively manage their network of obligations to accommodate external circumstances, by accepting, rejecting or attempting to negotiate their obligations, and attempting to have others accept these changed claims. This changes tend to concentrate on four areas of redefinition: 1) assessment of the reasonableness of the cost and benefits of claims to obligation and the determination of undue burdens; 2) redefinition of fair exchange rates for favors and of valid mutual obligations; 3) redefinition of membership claims and of relative proximity to ego; 4) redefinition of the hierarchies and legitimate enforcement structures of the group. These strategies cause egocentric networks that built upon kin and hometown in the "village" to mutate dramatically in new locations. Using ethnographic data on migrant businesspeople in Lhasa collected over three years, the paper illustrates the processes of these network management. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]