Volatility is an important variable in the financial market. We propose a model-free implied volatility method to measure the volatility and test the volatility risk premium. The model-free implied volatility does not...Volatility is an important variable in the financial market. We propose a model-free implied volatility method to measure the volatility and test the volatility risk premium. The model-free implied volatility does not depend on the option pricing model, and extracts information from all the option contracts. We provide empirical evidence from the S & P 500 index option that model-free implied volatility is more accurate to forecast the future volatility and the volatility risk premium does not exist.展开更多
The juvenile-to-adult transition in plants involves changes in vegetative growth and plant architecture;the timing of this transition has important implications for agriculture.The microRNA miR156 regulates this trans...The juvenile-to-adult transition in plants involves changes in vegetative growth and plant architecture;the timing of this transition has important implications for agriculture.The microRNA miR156 regulates this transition and shoot maturation in plants.In Arabidopsis thaliana,deposition of histone H3 trimethylation on lysine 27(H3K27me3,a repressive mark)at the MIR156A/C loci is regulated by Polycomb Repressive Complex 1(PRC1)or PRC2,depending on the developmental stage.The levels of miR156 progressively decline during shoot maturation.The amount of H3K27me3 at MIR156A/C loci affects miR156 levels;however,whether this epigenetic regulation is conserved remains unclear.Here,we found that in rice(Oryza sativa),the putative PRC1 subunit LIKE HETEROCHROMATIN PROTEIN 1(OsLHP1),with the miR156–SQUAMOSA PROMOTER BINDING PROTEIN-LIKE(SPL)module,affects developmental phase transitions.Loss of OsLHP1 function results in ectopic expression of MIR156B/C/I/E,phenocopy of miR156 overexpression,and reduced H3k27me3 levels at MIR156B/C/I/E.This indicates that OsLHP1 has functionally diverged from Arabidopsis LHP1.Genetic and transcriptome analyses of wild-type,miR156b/c-overexpression,and Oslhp1-2 mutant plants suggest that OsLHP1 acts upstream of miR156 and SPL during the juvenile-to-adult transition.Therefore,modifying the OsLHP1–miR156–SPL pathway may enable alteration of the vegetative period and plant architecture.展开更多
文摘Volatility is an important variable in the financial market. We propose a model-free implied volatility method to measure the volatility and test the volatility risk premium. The model-free implied volatility does not depend on the option pricing model, and extracts information from all the option contracts. We provide empirical evidence from the S & P 500 index option that model-free implied volatility is more accurate to forecast the future volatility and the volatility risk premium does not exist.
基金This researchwas financially supported by the National NaturalScience Foundation of China(91735304,31771887).
文摘The juvenile-to-adult transition in plants involves changes in vegetative growth and plant architecture;the timing of this transition has important implications for agriculture.The microRNA miR156 regulates this transition and shoot maturation in plants.In Arabidopsis thaliana,deposition of histone H3 trimethylation on lysine 27(H3K27me3,a repressive mark)at the MIR156A/C loci is regulated by Polycomb Repressive Complex 1(PRC1)or PRC2,depending on the developmental stage.The levels of miR156 progressively decline during shoot maturation.The amount of H3K27me3 at MIR156A/C loci affects miR156 levels;however,whether this epigenetic regulation is conserved remains unclear.Here,we found that in rice(Oryza sativa),the putative PRC1 subunit LIKE HETEROCHROMATIN PROTEIN 1(OsLHP1),with the miR156–SQUAMOSA PROMOTER BINDING PROTEIN-LIKE(SPL)module,affects developmental phase transitions.Loss of OsLHP1 function results in ectopic expression of MIR156B/C/I/E,phenocopy of miR156 overexpression,and reduced H3k27me3 levels at MIR156B/C/I/E.This indicates that OsLHP1 has functionally diverged from Arabidopsis LHP1.Genetic and transcriptome analyses of wild-type,miR156b/c-overexpression,and Oslhp1-2 mutant plants suggest that OsLHP1 acts upstream of miR156 and SPL during the juvenile-to-adult transition.Therefore,modifying the OsLHP1–miR156–SPL pathway may enable alteration of the vegetative period and plant architecture.
