Environmental unpredictability can influence strategies of maternal investment among eggs within a clutch. Models predict that breeding females should adopt a diversified bet-hedging strategy in unpredictable environm...Environmental unpredictability can influence strategies of maternal investment among eggs within a clutch. Models predict that breeding females should adopt a diversified bet-hedging strategy in unpredictable environments, but empirical field evidence from Asia is scarce. Here we tested this hypothesis by exploring spatial patterns in egg size along an altitudinal gradient in a frog species （Rana kukunoris） inhabiting the Tibetan Plateau. Within-clutch variability in egg size increased as the environment became variable （e.g., lower mean monthly temperature and mean monthly rainfall at higher altitudes）, and populations in environments with more unpredictable rainfall produced eggs that were smaller and more variable in size. We provide support for a diversified bet-hedging strategy in high-altitude environments, which experience dynamic weather patterns and therefore are of unpredictable environmental quality. This strategy may be an adaptive response to lower environmental quality and higher unpredictable environmental variance. Such a strategy should increase the likelihood of breeding success and maximize maternal lifetime fitness by producing offspring that are adapted to current environmental conditions. We speculate that in high-altitude environments prone to physical disturbance, breeding females are unable to consistently produce the optimal egg size due to physiological constraints imposed by environmental conditions （e.g., duration of the active season, food availability）. Species and populations whose breeding strategies are adapted to cope with uncertain environmental conditions by adjusting offspring size and therefore quality show a remarkable degree of ability to cope with future climatic changes.展开更多
This is a corpus-based contrastive study projected to find out the differences in using hedges in English business corre spondences between Chinese English learners and native speakers.
Dear Editor,Ferroptosis,an iron-dependent form of cell death driven by overwhelming lipid peroxidation,represents a vulnerability in cancers,and therapeutic strategies to further potentiate ferroptosis hold great pote...Dear Editor,Ferroptosis,an iron-dependent form of cell death driven by overwhelming lipid peroxidation,represents a vulnerability in cancers,and therapeutic strategies to further potentiate ferroptosis hold great potential for melanoma treatment.展开更多
Hedging, referring to the use of various lexical and syntactic features modifying and mitigating propositions and claims, is extensively employed in effective academic writing. However, the use of hedges seems to be q...Hedging, referring to the use of various lexical and syntactic features modifying and mitigating propositions and claims, is extensively employed in effective academic writing. However, the use of hedges seems to be quite problematic for lots of Chinese ESL learners. In view of the situation, this study explores the use of hedges in academic abstracts by a group of undergraduate English majors in a university in Hainan Province. After analyzing data from a corpus and interviews, several problems have been found in the use of hedging devices of these students, and relevant implications have been drawn to the teaching of hedging in the context, which can help the students produce more effective academic writing and to achieve greater university success.展开更多
This study examines the hedging effectiveness of financial innovations against crude oil investment risks,both before and during the COVID-19 pandemic.We focus on the non-energy exchange traded funds(ETFs)as proxies f...This study examines the hedging effectiveness of financial innovations against crude oil investment risks,both before and during the COVID-19 pandemic.We focus on the non-energy exchange traded funds(ETFs)as proxies for financial innovations given the potential positive correlation between energy variants and crude oil proxies.We employ a multivariate volatility modeling framework that accounts for important statistical features of the non-energy ETFs and oil price series in the computation of optimal weights and optimal hedging ratios.Results show evidence of hedging effectiveness for the financial innovations against oil market risks,with higher hedging performance observed during the pandemic.Overall,we show that sectoral financial innovations provide resilient investment options.Therefore,we propose that including the ETFs in an investment portfolio containing oil could improve risk-adjusted returns,especially in similar financial crisis as witnessed during the pandemic.In essence,our results are useful for investors in the global oil market seeking to maximize risk-adjusted returns when making investment decisions.Moreover,by exploring the role of structural breaks in the multivariate volatility framework,our attempts at establishing robustness for the results reveal that ignoring the same may lead to wrong conclusions about the hedging effectiveness.展开更多
In this article an attempt to enhance the awareness of hedging use in discourse analysis and academic writing is madeby analyzing hedges employed in two comparable texts.The discourse analysis is conducted from"c...In this article an attempt to enhance the awareness of hedging use in discourse analysis and academic writing is madeby analyzing hedges employed in two comparable texts.The discourse analysis is conducted from"content-oriented"hedges and"reader-oriented"hedges.The article suggests that hedging can dampen utterances and statements,weaken the force of what onesays and show politeness to the listeners or readers,which varies from different discourse styles of various genres.discourse marker;hedging;research article;news展开更多
For a class of manufacturing systems with homogeneous Markov machine failure rates,the stationary probability distribution of the part surplus can be calculated for given tentative values of hedging points. Some prope...For a class of manufacturing systems with homogeneous Markov machine failure rates,the stationary probability distribution of the part surplus can be calculated for given tentative values of hedging points. Some properties on the ordering of optimal hedging points are obtained.展开更多
The hedging problem for insiders is very important in the financial market.The locally risk minimizing hedging was adopted to solve this problem.Since the market was incomplete,the minimal martingale measure was chose...The hedging problem for insiders is very important in the financial market.The locally risk minimizing hedging was adopted to solve this problem.Since the market was incomplete,the minimal martingale measure was chosen as the equivalent martingale measure.By the F-S decomposition,the expression of the locally risk minimizing strategy was presented.Finally,the local risk minimization was applied to index tracking and its relationship with tracking error variance (TEV)-minimizing strategy was obtained.展开更多
In this paper, we consider a Markov switching Lévy process model in which the underlying risky assets are driven by the stochastic exponential of Markov switching Lévy process and then apply the model to opt...In this paper, we consider a Markov switching Lévy process model in which the underlying risky assets are driven by the stochastic exponential of Markov switching Lévy process and then apply the model to option pricing and hedging. In this model, the market interest rate, the volatility of the underlying risky assets and the N-state compensator,depend on unobservable states of the economy which are modeled by a continuous-time Hidden Markov process. We use the MEMM(minimal entropy martingale measure) as the equivalent martingale measure. The option price using this model is obtained by the Fourier transform method. We obtain a closed-form solution for the hedge ratio by applying the local risk minimizing hedging.展开更多
Under the background of energy conservation, the grid companies should give priority to consumptive hydropower, wind power and other clean electricity to fulfill their social responsibility and promote the carbon emis...Under the background of energy conservation, the grid companies should give priority to consumptive hydropower, wind power and other clean electricity to fulfill their social responsibility and promote the carbon emission reduction in power industry. But under the current power purchase mode, grid companies must first perform the contract. This is extremely uneconomical and not environmentally friendly. Based on hedging theory, this paper proposes a power purchase optimization model using the strategy of “compression and compensation”. If outer price is lower than the contract price, the grid can compress contract power appropriately, leaving more space for purchasing electricity;if outer price is not attractive enough, the grid should timely improve contract proportion, compensating the deviations of contract caused by "compression". Based on the strategy of "compression and compensation", it can effectively reduce the abandoned wind and water, enhance the economic and social benefits of provincial power grid.展开更多
This paper considered the problem of hedging a European call (put) option for a diffusion model where the asset price is influenced by n uncertain factors. The market is thus incomplete implying that perfect hedging i...This paper considered the problem of hedging a European call (put) option for a diffusion model where the asset price is influenced by n uncertain factors. The market is thus incomplete implying that perfect hedging is not possible. To derive a hedging strategy, it follows the approach based on the idea of hedging under a mean-variance criterion suggested by Schweizer. A very simple solution of this hedging problem by using the numeraire method was presented and some examples with explicit solutions were given.展开更多
Based on two different risk measurement criteria, this article studied the optimal hedging strategies of stock index futures in the case of asymmetric information, and discussed the influence of insider information on...Based on two different risk measurement criteria, this article studied the optimal hedging strategies of stock index futures in the case of asymmetric information, and discussed the influence of insider information on the hedging effect. Through simulation analysis, it can be shown that hedging people with insider information can save hedging costs to a certain extent, which also explains the reason why investors try to obtain corporate information in actual investment activities.展开更多
In this paper we investigate asymptotic behavior of error of a discrete time hedging strategy in a fractional Black-Scholes model in the sense of Wick-ItS-Skorohod integration. The rate of convergence of the hedging e...In this paper we investigate asymptotic behavior of error of a discrete time hedging strategy in a fractional Black-Scholes model in the sense of Wick-ItS-Skorohod integration. The rate of convergence of the hedging error due to discrete-time trading when the true strategy is known for the trader, is investigated. The result provides new statistical tools to study and detect the effect of the long-memory and the Hurst parameter for the error of discrete time hedging.展开更多
基金funded by the Natural Sciences Foundation for Distinguished Young Scholar of Sichuan (grant number 2016JQ0038)Key Foundation of Sichuan Provincial Department of Education (grant number 18ZA0255)the National Sciences Foundation of China (grant number 31670392)
文摘Environmental unpredictability can influence strategies of maternal investment among eggs within a clutch. Models predict that breeding females should adopt a diversified bet-hedging strategy in unpredictable environments, but empirical field evidence from Asia is scarce. Here we tested this hypothesis by exploring spatial patterns in egg size along an altitudinal gradient in a frog species （Rana kukunoris） inhabiting the Tibetan Plateau. Within-clutch variability in egg size increased as the environment became variable （e.g., lower mean monthly temperature and mean monthly rainfall at higher altitudes）, and populations in environments with more unpredictable rainfall produced eggs that were smaller and more variable in size. We provide support for a diversified bet-hedging strategy in high-altitude environments, which experience dynamic weather patterns and therefore are of unpredictable environmental quality. This strategy may be an adaptive response to lower environmental quality and higher unpredictable environmental variance. Such a strategy should increase the likelihood of breeding success and maximize maternal lifetime fitness by producing offspring that are adapted to current environmental conditions. We speculate that in high-altitude environments prone to physical disturbance, breeding females are unable to consistently produce the optimal egg size due to physiological constraints imposed by environmental conditions （e.g., duration of the active season, food availability）. Species and populations whose breeding strategies are adapted to cope with uncertain environmental conditions by adjusting offspring size and therefore quality show a remarkable degree of ability to cope with future climatic changes.
文摘This is a corpus-based contrastive study projected to find out the differences in using hedges in English business corre spondences between Chinese English learners and native speakers.
基金This work was supported by grants from the National Natural Science Foundation of China(82103183,82102803,82272849)the Natural Science Foundation of Hunan Province(2022JJ40767,2021JJ40976)+1 种基金the Natural Science Fund for Outstanding Youths in Hunan Province(2023JJ20093)the National Key Research and Development Program(2022YFC2504700).
文摘Dear Editor,Ferroptosis,an iron-dependent form of cell death driven by overwhelming lipid peroxidation,represents a vulnerability in cancers,and therapeutic strategies to further potentiate ferroptosis hold great potential for melanoma treatment.
文摘Hedging, referring to the use of various lexical and syntactic features modifying and mitigating propositions and claims, is extensively employed in effective academic writing. However, the use of hedges seems to be quite problematic for lots of Chinese ESL learners. In view of the situation, this study explores the use of hedges in academic abstracts by a group of undergraduate English majors in a university in Hainan Province. After analyzing data from a corpus and interviews, several problems have been found in the use of hedging devices of these students, and relevant implications have been drawn to the teaching of hedging in the context, which can help the students produce more effective academic writing and to achieve greater university success.
文摘This study examines the hedging effectiveness of financial innovations against crude oil investment risks,both before and during the COVID-19 pandemic.We focus on the non-energy exchange traded funds(ETFs)as proxies for financial innovations given the potential positive correlation between energy variants and crude oil proxies.We employ a multivariate volatility modeling framework that accounts for important statistical features of the non-energy ETFs and oil price series in the computation of optimal weights and optimal hedging ratios.Results show evidence of hedging effectiveness for the financial innovations against oil market risks,with higher hedging performance observed during the pandemic.Overall,we show that sectoral financial innovations provide resilient investment options.Therefore,we propose that including the ETFs in an investment portfolio containing oil could improve risk-adjusted returns,especially in similar financial crisis as witnessed during the pandemic.In essence,our results are useful for investors in the global oil market seeking to maximize risk-adjusted returns when making investment decisions.Moreover,by exploring the role of structural breaks in the multivariate volatility framework,our attempts at establishing robustness for the results reveal that ignoring the same may lead to wrong conclusions about the hedging effectiveness.
文摘In this article an attempt to enhance the awareness of hedging use in discourse analysis and academic writing is madeby analyzing hedges employed in two comparable texts.The discourse analysis is conducted from"content-oriented"hedges and"reader-oriented"hedges.The article suggests that hedging can dampen utterances and statements,weaken the force of what onesays and show politeness to the listeners or readers,which varies from different discourse styles of various genres.discourse marker;hedging;research article;news
文摘For a class of manufacturing systems with homogeneous Markov machine failure rates,the stationary probability distribution of the part surplus can be calculated for given tentative values of hedging points. Some properties on the ordering of optimal hedging points are obtained.
基金National Natural Science Foundations of China (No. 11071076,No. 11126124)
文摘The hedging problem for insiders is very important in the financial market.The locally risk minimizing hedging was adopted to solve this problem.Since the market was incomplete,the minimal martingale measure was chosen as the equivalent martingale measure.By the F-S decomposition,the expression of the locally risk minimizing strategy was presented.Finally,the local risk minimization was applied to index tracking and its relationship with tracking error variance (TEV)-minimizing strategy was obtained.
基金Supported by the National Natural Science Foundation of China(11201221)Supported by the Natural Science Foundation of Jiangsu Province(BK2012468)
文摘In this paper, we consider a Markov switching Lévy process model in which the underlying risky assets are driven by the stochastic exponential of Markov switching Lévy process and then apply the model to option pricing and hedging. In this model, the market interest rate, the volatility of the underlying risky assets and the N-state compensator,depend on unobservable states of the economy which are modeled by a continuous-time Hidden Markov process. We use the MEMM(minimal entropy martingale measure) as the equivalent martingale measure. The option price using this model is obtained by the Fourier transform method. We obtain a closed-form solution for the hedge ratio by applying the local risk minimizing hedging.
文摘Under the background of energy conservation, the grid companies should give priority to consumptive hydropower, wind power and other clean electricity to fulfill their social responsibility and promote the carbon emission reduction in power industry. But under the current power purchase mode, grid companies must first perform the contract. This is extremely uneconomical and not environmentally friendly. Based on hedging theory, this paper proposes a power purchase optimization model using the strategy of “compression and compensation”. If outer price is lower than the contract price, the grid can compress contract power appropriately, leaving more space for purchasing electricity;if outer price is not attractive enough, the grid should timely improve contract proportion, compensating the deviations of contract caused by "compression". Based on the strategy of "compression and compensation", it can effectively reduce the abandoned wind and water, enhance the economic and social benefits of provincial power grid.
基金National Natural Science Foundation ofChina( 10 1710 66) and Shanghai Key Project( 0 2 DJ14 0 63 )
文摘This paper considered the problem of hedging a European call (put) option for a diffusion model where the asset price is influenced by n uncertain factors. The market is thus incomplete implying that perfect hedging is not possible. To derive a hedging strategy, it follows the approach based on the idea of hedging under a mean-variance criterion suggested by Schweizer. A very simple solution of this hedging problem by using the numeraire method was presented and some examples with explicit solutions were given.
文摘Based on two different risk measurement criteria, this article studied the optimal hedging strategies of stock index futures in the case of asymmetric information, and discussed the influence of insider information on the hedging effect. Through simulation analysis, it can be shown that hedging people with insider information can save hedging costs to a certain extent, which also explains the reason why investors try to obtain corporate information in actual investment activities.
基金Supported by the National Natural Science Foundation of China(11671115)the Natural Science Foundation of Zhejiang Province(LY14A010025)
文摘In this paper we investigate asymptotic behavior of error of a discrete time hedging strategy in a fractional Black-Scholes model in the sense of Wick-ItS-Skorohod integration. The rate of convergence of the hedging error due to discrete-time trading when the true strategy is known for the trader, is investigated. The result provides new statistical tools to study and detect the effect of the long-memory and the Hurst parameter for the error of discrete time hedging.
