Abstract： Migration process has become increasingly important in recent research on population and the environment. A majority of the existing migration and environment literature has focused on the environmental cau...Abstract： Migration process has become increasingly important in recent research on population and the environment. A majority of the existing migration and environment literature has focused on the environmental causes and determinants of migration. With the largest rural-to-urban migration flow in world history, and growing concerns about the environmental problems accompanying its fast economic development, China provides a particularly important case for migration and environment research. This paper reviews major migration theories and recent research on environmental effects on migration, with specific attention to the influences of en- vironmental factors on rural-to-urban labor migration in China. A comprehensive multilevel conceptual framework is developed for studying the environmental causes of rural-to-urban migration in China. The effects of land resources on household labor migration decisions in rural China are explored to illustrate the application of this framework.展开更多
Runner bean is usually grown in Chile as household plantings, in small surfaces with trellis support. Several studies were made to grow runner beans extensively without trellis support, like common beans are grown. Th...Runner bean is usually grown in Chile as household plantings, in small surfaces with trellis support. Several studies were made to grow runner beans extensively without trellis support, like common beans are grown. Three runner bean ecotypes were evaluated, with and without trellis support. Although the highest yield was obtained with trellis support, significant yields were obtained without trellis. Thus, this specie can be established without support like the common bean, allowing a great economic advantage especially at large scale plantings. The ecotype named ＂Quilapallar＂ was selected by its white and large grains and excellent cooking quality. Then, seed rates and dry grain yield were compared with commercial varieties of common bean. There was not statistical difference in yield among row distances, except when this was 25 cm apart. Besides, there was not statistical difference among Quilapallar and Torcaza INIA, although the later is a common bean variety with a high yield potential.展开更多
microRNAs regulate diverse biological processes such as development and aging by promoting degradation or inhibiting translation of their target mRNAs. In this study, we have found that the miR-58 family microRNAs reg...microRNAs regulate diverse biological processes such as development and aging by promoting degradation or inhibiting translation of their target mRNAs. In this study, we have found that the miR-58 family microRNAs regulate lifespan in C.elegans. Intriguingly, members of the miR-58 family affect lifespan differently, sometimes in opposite directions, and have complex genetic interactions. The abundances of the miR-58 family miRNAs are up-regulated in the long-lived daf-2 mutant in a daf-16-dependent manner, indicating that these miRNAs are effectors of insulin signaling in C. elegans. We also found that miR-58 is regulated by insulin signaling and partially required for the lifespan extension mediated by reduced insulin signaling,germline ablation, dietary restriction, and mild mitochondrial dysfunction. We further identified the daf-21, ins-1, and isw-1 mRNAs as endogenous targets of miR-58. Our study shows that miRNAs function in multiple lifespan extension mechanisms,and that the seed sequence is not the dominant factor defining the role of a miRNA in lifespan regulation.展开更多
基金funded by dissertation research grants from the Geography and Spatial Sciences Program of the National Science Foundation,the Worldwide Universities Network,and the Rural Sociological Society
文摘Abstract： Migration process has become increasingly important in recent research on population and the environment. A majority of the existing migration and environment literature has focused on the environmental causes and determinants of migration. With the largest rural-to-urban migration flow in world history, and growing concerns about the environmental problems accompanying its fast economic development, China provides a particularly important case for migration and environment research. This paper reviews major migration theories and recent research on environmental effects on migration, with specific attention to the influences of en- vironmental factors on rural-to-urban labor migration in China. A comprehensive multilevel conceptual framework is developed for studying the environmental causes of rural-to-urban migration in China. The effects of land resources on household labor migration decisions in rural China are explored to illustrate the application of this framework.
文摘Runner bean is usually grown in Chile as household plantings, in small surfaces with trellis support. Several studies were made to grow runner beans extensively without trellis support, like common beans are grown. Three runner bean ecotypes were evaluated, with and without trellis support. Although the highest yield was obtained with trellis support, significant yields were obtained without trellis. Thus, this specie can be established without support like the common bean, allowing a great economic advantage especially at large scale plantings. The ecotype named ＂Quilapallar＂ was selected by its white and large grains and excellent cooking quality. Then, seed rates and dry grain yield were compared with commercial varieties of common bean. There was not statistical difference in yield among row distances, except when this was 25 cm apart. Besides, there was not statistical difference among Quilapallar and Torcaza INIA, although the later is a common bean variety with a high yield potential.
基金supported by the NIH Office of Infrastructure Programs (P40 OD010440), for providing worm strainssupported by Beijing Municipal Science and Technology Commission (a fund for cultivation and development of innovation base) and the Ministry of Science and Technology of China (2014CB84980001)
文摘microRNAs regulate diverse biological processes such as development and aging by promoting degradation or inhibiting translation of their target mRNAs. In this study, we have found that the miR-58 family microRNAs regulate lifespan in C.elegans. Intriguingly, members of the miR-58 family affect lifespan differently, sometimes in opposite directions, and have complex genetic interactions. The abundances of the miR-58 family miRNAs are up-regulated in the long-lived daf-2 mutant in a daf-16-dependent manner, indicating that these miRNAs are effectors of insulin signaling in C. elegans. We also found that miR-58 is regulated by insulin signaling and partially required for the lifespan extension mediated by reduced insulin signaling,germline ablation, dietary restriction, and mild mitochondrial dysfunction. We further identified the daf-21, ins-1, and isw-1 mRNAs as endogenous targets of miR-58. Our study shows that miRNAs function in multiple lifespan extension mechanisms,and that the seed sequence is not the dominant factor defining the role of a miRNA in lifespan regulation.
