The Emission Gap Report 2013 from the United Nations Environment Program showed that adopting conservation tillage such as no-till,as an alternative to conventional tillage,contributes significantly to climate change ...The Emission Gap Report 2013 from the United Nations Environment Program showed that adopting conservation tillage such as no-till,as an alternative to conventional tillage,contributes significantly to climate change mitigation through carbon sequestration.However,substantial amounts of soil carbon are lost when farmers interrupt continuous use of conservation tillage with conventional tillage.Conservation tillage is spreading,but little is known about the behavioral persistence in tillage decisions.To address the gap in the literature,we estimate county-specific Markov models of tillage-crop choices,and use the predicted probabilities of alternative two-and three-year tillage rotations to evaluate spatial variation and temporal persistence in conservation tillage adoption for the state of lowa (U.S).We find that the county-average probabilities of continuous conservation tillage range between 0.133 and 0.295,and vary significantly among crop rotations.We also find a statistically strong positive effect of the incidence of the highly erodible land on the county-average use of continuous conservation tillage.Our results underscore the importance of dynamic modeling for understanding behavioral persistence in tillage decisions,and the interdependence between farmers' crop and tillage rotations.展开更多
Since its rediscovery in the mid-1990s,FOXP31 regulatory T cells(Tregs)have climbed the rank to become commander-in-chief of the immune system.They possess diverse power and ability to orchestrate the immune system in...Since its rediscovery in the mid-1990s,FOXP31 regulatory T cells(Tregs)have climbed the rank to become commander-in-chief of the immune system.They possess diverse power and ability to orchestrate the immune system in time of inflammation and infection as well as in time of harmony and homeostasis.To be the commander-in-chief,they must be equipped with both offensive and defensive weaponry.This review will focus on the function of transforming growth factor-b(TGF-b)as the sword,the wand,and the shield of Tregs.Functioning as a sword,this review will begin with a discussion of the evidence that supports how Tregs utilize TGFb to paralyze cell activation and differentiation to suppress immune response.It will next provide evidence on how TGF-b from Tregs acts as a wand to convert naıve T cells into iTregs and Th17 to aid in their combat against inflammation and infection.Lastly,the review will present evidence on the role of TGF-b produced by Tregs in providing a shield to protect and maintain Tregs against apoptosis and destabilization when surrounded by inflammation and constant stimulation.This triadic function of TGF-b empowers Tregs with the responsibility and burden to maintain homeostasis,promote immune tolerance,and regulate host defense against foreign pathogens.展开更多
文摘The Emission Gap Report 2013 from the United Nations Environment Program showed that adopting conservation tillage such as no-till,as an alternative to conventional tillage,contributes significantly to climate change mitigation through carbon sequestration.However,substantial amounts of soil carbon are lost when farmers interrupt continuous use of conservation tillage with conventional tillage.Conservation tillage is spreading,but little is known about the behavioral persistence in tillage decisions.To address the gap in the literature,we estimate county-specific Markov models of tillage-crop choices,and use the predicted probabilities of alternative two-and three-year tillage rotations to evaluate spatial variation and temporal persistence in conservation tillage adoption for the state of lowa (U.S).We find that the county-average probabilities of continuous conservation tillage range between 0.133 and 0.295,and vary significantly among crop rotations.We also find a statistically strong positive effect of the incidence of the highly erodible land on the county-average use of continuous conservation tillage.Our results underscore the importance of dynamic modeling for understanding behavioral persistence in tillage decisions,and the interdependence between farmers' crop and tillage rotations.
基金The research provided in this manuscript was supported by the Department of Pedi atrics,The University of T exas Health Science Center at Houston.
文摘Since its rediscovery in the mid-1990s,FOXP31 regulatory T cells(Tregs)have climbed the rank to become commander-in-chief of the immune system.They possess diverse power and ability to orchestrate the immune system in time of inflammation and infection as well as in time of harmony and homeostasis.To be the commander-in-chief,they must be equipped with both offensive and defensive weaponry.This review will focus on the function of transforming growth factor-b(TGF-b)as the sword,the wand,and the shield of Tregs.Functioning as a sword,this review will begin with a discussion of the evidence that supports how Tregs utilize TGFb to paralyze cell activation and differentiation to suppress immune response.It will next provide evidence on how TGF-b from Tregs acts as a wand to convert naıve T cells into iTregs and Th17 to aid in their combat against inflammation and infection.Lastly,the review will present evidence on the role of TGF-b produced by Tregs in providing a shield to protect and maintain Tregs against apoptosis and destabilization when surrounded by inflammation and constant stimulation.This triadic function of TGF-b empowers Tregs with the responsibility and burden to maintain homeostasis,promote immune tolerance,and regulate host defense against foreign pathogens.
