大学毕业生面向非公有制单位就业存在的问题及对策

本文阐述了当前我国大学毕业生面向非公有制单位就业所存在的主要问题 ,并从多角度探讨了解决问题的办法     

Biotechnical portfolio management of mixed-species forests

Based upon the historical data—obtained from the French National Forest Inventory—on the tree species’ productivities, assimilated to be a measure of return on investment, as well as on their variances as sources of risk, we apply the portfolio selection theory in order to optimize the species distributions in France. We thus determine the optimal return-risk combinations of tree species and map them per administrative department. We also estimate the resistance of optimal portfolios using the species’ probabilities of presence. Our results show that greater weights in the optimal portfolios match with higher probabilities of presence, implying that foresters have incentives to invest in the most resilient species.