To determine the optimal time for harvesting the seeds of Gui 39722, which is the female parent of a newly-developed maize hybrid Guidan 0810, the cobs of Gui 39722 were harvested 31 （the first stage）, 34 （the seco...To determine the optimal time for harvesting the seeds of Gui 39722, which is the female parent of a newly-developed maize hybrid Guidan 0810, the cobs of Gui 39722 were harvested 31 （the first stage）, 34 （the second stage）, 37 （the third stage）, 40 （the fourth stage）, 43 （the fifth stage） and 46 （the sixth stage） d after pollination and oven dried at 38 ~C to constant weight. Then, the 1 000-ker- nel weight, germination rate and the agronomic traits of three-leaf seedlings were measured and compared. The results showed that the seeds of Gui 39722 harvest- ed 43 d after pollination （the fifth stage） had the greatest germination rate, seedling height, vigor index, root dry weight, shoot dry weight and germination potential, and high 1 000-kernel weight （very close to the highest level）, root length, number of roots per seedling and root-shoot ratio. Therefore, 43 d after pollination was the op- timal time for harvesting the seeds of Gui 39722, when the effective accumulated temperature after pollination reached 780.7 ℃ and the ear leaf dried. The seeds harvested at this stage had the highest yield and the best quality. Field sampling revealed that 89.00% to 95.00% （with an average of 91.15%） of the seedlings of six stages of seeds grew well.展开更多
We focus on the asymptotic convergence behavior of the hedging errors of European stock option due to discrete hedging under stochastic interest rates. There are two kinds of BS-type discrete hedging differ in hedging...We focus on the asymptotic convergence behavior of the hedging errors of European stock option due to discrete hedging under stochastic interest rates. There are two kinds of BS-type discrete hedging differ in hedging instruments: one is the portfolio of underlying stock, zero coupon bond, and the money market account (Strategy BSI); the other is the underlying stock, zero coupon bond (Strategy BSII). Similar to the results of the deterministic interest rate case, we show that convergence speed of the discounted hedging errors is 1/2-order of trading frequency for both strategies. Then, we prove each of the BS-type strategy is not only locally optimal, but also globally optimal under the corresponding measure. Finally, we give some numerical examples to illustrate the results. All the discussion is based on non-arbitrage condition and zero transaction cost.展开更多
基金Supported by Key Scientific Research Program of Guangxi(AB16380133,AB16380140)Agricultural Science and Technology Achievement Transformation Fund of Guangxi(1346004-16)+1 种基金the Scientific and Technological Development Project of Guangxi Academy of Agricultural Sciences[2015YT24,201303(A)]Agricultural Science and Technology Achievement Transformation Fund of Ministry of Science and Technology(2013GB2E100378)~~
文摘To determine the optimal time for harvesting the seeds of Gui 39722, which is the female parent of a newly-developed maize hybrid Guidan 0810, the cobs of Gui 39722 were harvested 31 （the first stage）, 34 （the second stage）, 37 （the third stage）, 40 （the fourth stage）, 43 （the fifth stage） and 46 （the sixth stage） d after pollination and oven dried at 38 ~C to constant weight. Then, the 1 000-ker- nel weight, germination rate and the agronomic traits of three-leaf seedlings were measured and compared. The results showed that the seeds of Gui 39722 harvest- ed 43 d after pollination （the fifth stage） had the greatest germination rate, seedling height, vigor index, root dry weight, shoot dry weight and germination potential, and high 1 000-kernel weight （very close to the highest level）, root length, number of roots per seedling and root-shoot ratio. Therefore, 43 d after pollination was the op- timal time for harvesting the seeds of Gui 39722, when the effective accumulated temperature after pollination reached 780.7 ℃ and the ear leaf dried. The seeds harvested at this stage had the highest yield and the best quality. Field sampling revealed that 89.00% to 95.00% （with an average of 91.15%） of the seedlings of six stages of seeds grew well.
基金supported by National Basic Research Program of China (Grant No.2007CB814905)
文摘We focus on the asymptotic convergence behavior of the hedging errors of European stock option due to discrete hedging under stochastic interest rates. There are two kinds of BS-type discrete hedging differ in hedging instruments: one is the portfolio of underlying stock, zero coupon bond, and the money market account (Strategy BSI); the other is the underlying stock, zero coupon bond (Strategy BSII). Similar to the results of the deterministic interest rate case, we show that convergence speed of the discounted hedging errors is 1/2-order of trading frequency for both strategies. Then, we prove each of the BS-type strategy is not only locally optimal, but also globally optimal under the corresponding measure. Finally, we give some numerical examples to illustrate the results. All the discussion is based on non-arbitrage condition and zero transaction cost.
