In 2010, Chinese maize yields increased from 961.5 kg ha-1 in 1949 to 5 453.8 kg ha-L This increase is the result of genetic improvements, an increase in nitrogen application, and refinement of planting densities. The...In 2010, Chinese maize yields increased from 961.5 kg ha-1 in 1949 to 5 453.8 kg ha-L This increase is the result of genetic improvements, an increase in nitrogen application, and refinement of planting densities. The objective of this study was to provide a theoretical basis for maize production research by analyzing the maize yield gain characteristics. Six varieties of maize were selected for the study; each selection is representative of a typical or commonly used maize variety from a specific decade, beginning from the 1950s and continuing through each decade into the 2000s. The selections and their corresponding decade were as follows： Baihe, 1950s; Jidan 101, 1960s; Zhongdan 2, 1970s; Yedan 13, 1980s; Zhengdan 958, 1990s; and Xianyu 335, 2000s. Each variety was planted under four different densities （37 500, 52 500, 67 500, and 82 500 plants ha-0 and four different nitrogen applications （0, 150, 225, and 300 kg ha-1 to study the effects on yield gain characteristics. The obtained results demonstrated that there was a maize yield increase of 123.19% between the 1950s variety and the 2000s variety. Modern Chinese maize varieties had a higher yield advantage. They also displayed the additional potential to acquire higher yield under increased planting densities and nitrogen applications. At the present cultivation levels （planting at 67 500 plants ha-~ with 225 kg ha-1 nitrogen application）, the contribution types and corresponding yield increase percentages were as follows： genetic improvement, 45.37%; agronomic-management improvement, 30.94%; and genotype× agronomicmanagement interaction, 23.69%. At high-yielding cultivation levels （planting at 82 500 plants ha-1 with 300 kg ha-1 nitrogen application）, the contribution types and corresponding yield increase percentages were as follows： genetic improvement, 31.30%; agronomic-management improvement, 36.23%; and genotype × agronomic-management interaction, 32.47%. The contribution of agronomic-management and genotype ×agronomic-management 展开更多
In May of 2007,the second generation selected （SS） and control （SC） groups of pearl oyster Pinctada martensii were established by selecting 10% breeders with the largest and mean shell length,respectively,from the...In May of 2007,the second generation selected （SS） and control （SC） groups of pearl oyster Pinctada martensii were established by selecting 10% breeders with the largest and mean shell length,respectively,from the first generation selected group.Growth performance of the SS and SC groups were compared on the basis of measurement data at Days 8,18,60,95,195 and 365.On Day 365,100 individuals （60.0–75.0 mm at shell length） were sampled from each group and then subjected to the experiment where physiological parameters such as filtrate rate,oxygen consumption and ammonia excretion were measured at 15,20,25 and 30°C.The results show that the SS group had significantly larger mean shell length and shell height than the SC group at Days 8,18,60,95,195 and 365 （P 0.05）.The genetic gains at different ages varied from 6.0% to 17.0% for shell length and 5.7% to 14.6% for shell height,respectively.At 15,20,25 and 30 ° C,the SS groups had significantly larger filtrate rate than the SC group （P 0.05）.At 15 and 25 °C,the differences in oxygen consumption rate between the SS and SC groups were not significant （P 0.05）.At 20 and 30 °C,however,the oxygen consumption rate of the SS group was significantly larger than the SC group （P 0.05）.At 15,20,25 and 30 °C,there were no significant differences in ammonia excretion rate between the SS and SC groups （P 0.05）.The present results indicate that there existed considerable genetic variability in the base population and a further selection could be likely fruitful.Mass selection for faster growth might produce animals that had higher intake of metabolizable energy by virtue of faster filtrating behavior.展开更多
Using a sample of state-owned enterprises(SOEs) listed on the Shanghai and Shenzhen Stock Exchanges during the 1999-2009 period,we investigate the effects of overemployment on executives' pay-for-performance sensi...Using a sample of state-owned enterprises(SOEs) listed on the Shanghai and Shenzhen Stock Exchanges during the 1999-2009 period,we investigate the effects of overemployment on executives' pay-for-performance sensitivity(PPS) and analyze how the behavior of firms with high/low PPS affects the number of surplus employees.We find the existence of a redundant workforce significantly weakens PPS and the role of accounting measures in performance assessment.In contrast to prior literature,we find that higher PPS is associated with a stronger incentive to lay off redundant employees and to limit future employee numbers.We also find that weaker government intervention strengthens managerial control over the future size of the workforce.Finally,our findings suggest that a heavier government policy burden on SOEs leads to lower tax rates and more government gains.展开更多
To warn the cascading failures caused by cyberattacks(CFCAs)in real time and reduce their damage on cyber-physical power systems(CPPSs),a novel early warning method based on attack gains and cost principle(AGCP)is pro...To warn the cascading failures caused by cyberattacks(CFCAs)in real time and reduce their damage on cyber-physical power systems(CPPSs),a novel early warning method based on attack gains and cost principle(AGCP)is proposed.Firstly,according to the CFCA characteristics,the leading role of attackers in the whole evolutionary process is discussed.The breaking out of a CFCA is deduced based on the AGCP from the view of attackers,and the priority order of all CFCAs is then provided.Then,the method to calculate the probability of CFCAs is proposed,and an early warning model for CFCA is designed.Finally,to verify the effectiveness of this method,a variety of CFCAs are simulated in a local CPPS model based on the IEEE 39-bus system.The experimental results demonstrate that this method can be used as a reliable assistant analysis technology to facilitate early warning of CFCAs.展开更多
[Objective] The paper was to investigate the effects of adding Shuanghuanglian propolis oral liquid in drinking water on growth performance,slaughter performance and meat quality of broilers. [Method]Ninety one-day-ol...[Objective] The paper was to investigate the effects of adding Shuanghuanglian propolis oral liquid in drinking water on growth performance,slaughter performance and meat quality of broilers. [Method]Ninety one-day-old broilers were randomly divided into three groups（ group Ⅰ,group Ⅱ and group Ⅲ） ： group Ⅰ was the control group,and groups Ⅱ and Ⅲ were added 0. 5 and 1. 0 mL / L Shuanghuanglian propolis oral liquid in drinking water,respectively.[Result] Compared with broilers in group I,the average daily feed intakes of broilers in group Ⅱ and group Ⅲ were increased by 0. 86%（ P 〉 0. 05） and 1. 10%（ P 〉 0. 05）,respectively; the average daily gains were increased by 2. 33%（ P 〈 0. 05） and 4. 43%（ P 〈 0. 05）,respectively; the feed gain ratios were decreased by 1. 05%（ P 〉0. 05） and 2. 63%（ P 〈0. 05）,respectively; the slaughter rates were increased by 0. 94%（ P 〉0. 05） and 1. 70%（ P 〈0. 05）,respectively; the eviscerated rates were increased by 0. 52%（ P 〉 0. 05） and 1. 15%（ P 〉 0. 05）,respectively; the semi-eviscerated rates were increased by 1. 51%（ P 〈 0. 05） and 2.23%（ P 〈 0. 05）,respectively; the breast muscle rates were increased by 3. 77%（ P 〈 0. 05） and 5. 51%（ P 〈 0. 05）,respectively; the leg muscle rates were increased by 1. 96%（ P 〉 0. 05） and 4. 09%（ P 〈 0. 05）,respectively; the lightness（ L＊） were decreased by 0. 96%（ P 〉 0. 05） and 1. 47%（ P 〉 0. 05）,respectively; the redness（ a＊） were increased by 1. 24%（ P 〈 0. 05） and 1. 86%（ P 〈 0. 05）,respectively; the yellowness（ b＊） were decreased by 0. 44%（ P 〉0. 05） and 1. 03%（ P 〈0. 05）,respectively; the drip losses were decreased by 1. 22%（ P 〈0. 05） and 1. 56%（ P 〈0. 05）,respectively; the cooking losses were decreased by 1. 76%（ P 〉 0. 05） and 2. 89%（ P 〈 0. 05）,respectively. [Conclusion]Adding 0. 5 and 1. 0 mL / L Shuanghuanglian propolis oral liquid in drinking wa展开更多
Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relati...Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relating to forest types, and estimated the total tree biomass carbon stocks and projected gains through natural stand development by 2020 and 2050 in the Daqing Mountain Nature Reserve based on Category II data of the Forest Inventory of Inner Mongolia for the period ending 2008. Over a total area of 388,577 ha,this nature reserve currently stores an estimated 2221 Gg C in tree aboveground biomass alone, with potential to grow by more than 30 % to reach 2938 Gg C by 2020 and nearly double to 4092 Gg C by 2050 through natural development of the existing forest stands. The tree biomass carbon density and potential gain in tree biomass carbon stocks vary markedly among forest types and with stand development.The variations in the potential change of tree biomass carbon density for the periods 2008–2020 and 2008–2050 among forest types partly reflect the varying relationships of tree biomass carbon density with stand age for different tree species, and partly are attributable to variations in the stand age structure among different forest types. Of the major forest types, the ranking of projected changes in tree biomass carbon density are not consistent with variations in the relationship between tree biomass carbon density and stand age, neither are they explainable by variations in stand age structures, implying the interactive effect between forest type and stand dynamics on temporal changes in tree biomass carbon density. Birch rank highest for future biomass carbon sequestration because of its dominance in cover area and better age structure for potential gain in tree biomass carbon stocks. Poplar and larch were out-performers compared to other forest types given their greater contribution to total tree biomass carbon stocks relative to their distributional areas. Findings in this study illustrate th展开更多
基金supported by the National Basic Research Program of China (2009CB118605)
文摘In 2010, Chinese maize yields increased from 961.5 kg ha-1 in 1949 to 5 453.8 kg ha-L This increase is the result of genetic improvements, an increase in nitrogen application, and refinement of planting densities. The objective of this study was to provide a theoretical basis for maize production research by analyzing the maize yield gain characteristics. Six varieties of maize were selected for the study; each selection is representative of a typical or commonly used maize variety from a specific decade, beginning from the 1950s and continuing through each decade into the 2000s. The selections and their corresponding decade were as follows： Baihe, 1950s; Jidan 101, 1960s; Zhongdan 2, 1970s; Yedan 13, 1980s; Zhengdan 958, 1990s; and Xianyu 335, 2000s. Each variety was planted under four different densities （37 500, 52 500, 67 500, and 82 500 plants ha-0 and four different nitrogen applications （0, 150, 225, and 300 kg ha-1 to study the effects on yield gain characteristics. The obtained results demonstrated that there was a maize yield increase of 123.19% between the 1950s variety and the 2000s variety. Modern Chinese maize varieties had a higher yield advantage. They also displayed the additional potential to acquire higher yield under increased planting densities and nitrogen applications. At the present cultivation levels （planting at 67 500 plants ha-~ with 225 kg ha-1 nitrogen application）, the contribution types and corresponding yield increase percentages were as follows： genetic improvement, 45.37%; agronomic-management improvement, 30.94%; and genotype× agronomicmanagement interaction, 23.69%. At high-yielding cultivation levels （planting at 82 500 plants ha-1 with 300 kg ha-1 nitrogen application）, the contribution types and corresponding yield increase percentages were as follows： genetic improvement, 31.30%; agronomic-management improvement, 36.23%; and genotype × agronomic-management interaction, 32.47%. The contribution of agronomic-management and genotype ×agronomic-management
基金The National Key Technology R&D Program in the 11th Five Year Plan of China under contract No. 2007BAD29B01-2National Department Public Benefit Research Foundation under contract No. nyhyzx 07-048Guangdong Marine and Fishery Bureau under contract Nos A200708C01, A200908A02 and A200908A05
文摘In May of 2007,the second generation selected （SS） and control （SC） groups of pearl oyster Pinctada martensii were established by selecting 10% breeders with the largest and mean shell length,respectively,from the first generation selected group.Growth performance of the SS and SC groups were compared on the basis of measurement data at Days 8,18,60,95,195 and 365.On Day 365,100 individuals （60.0–75.0 mm at shell length） were sampled from each group and then subjected to the experiment where physiological parameters such as filtrate rate,oxygen consumption and ammonia excretion were measured at 15,20,25 and 30°C.The results show that the SS group had significantly larger mean shell length and shell height than the SC group at Days 8,18,60,95,195 and 365 （P 0.05）.The genetic gains at different ages varied from 6.0% to 17.0% for shell length and 5.7% to 14.6% for shell height,respectively.At 15,20,25 and 30 ° C,the SS groups had significantly larger filtrate rate than the SC group （P 0.05）.At 15 and 25 °C,the differences in oxygen consumption rate between the SS and SC groups were not significant （P 0.05）.At 20 and 30 °C,however,the oxygen consumption rate of the SS group was significantly larger than the SC group （P 0.05）.At 15,20,25 and 30 °C,there were no significant differences in ammonia excretion rate between the SS and SC groups （P 0.05）.The present results indicate that there existed considerable genetic variability in the base population and a further selection could be likely fruitful.Mass selection for faster growth might produce animals that had higher intake of metabolizable energy by virtue of faster filtrating behavior.
基金supported by the National Social Science Foundation(Grant No.08CJY009)the Philosophical and Social Science Foundation of Education Department of Jiangsu Province(Grant No.07SJD630016)support from the IAPHD Project of Nanjing University
文摘Using a sample of state-owned enterprises(SOEs) listed on the Shanghai and Shenzhen Stock Exchanges during the 1999-2009 period,we investigate the effects of overemployment on executives' pay-for-performance sensitivity(PPS) and analyze how the behavior of firms with high/low PPS affects the number of surplus employees.We find the existence of a redundant workforce significantly weakens PPS and the role of accounting measures in performance assessment.In contrast to prior literature,we find that higher PPS is associated with a stronger incentive to lay off redundant employees and to limit future employee numbers.We also find that weaker government intervention strengthens managerial control over the future size of the workforce.Finally,our findings suggest that a heavier government policy burden on SOEs leads to lower tax rates and more government gains.
基金supported by the National Key Research and Development Program of China(No.2017YFB0903000)National Natural Science Foundation of China(No.61471328)Natural Science Foundation of Tianjin City(No.15JCQNJC07000).
文摘To warn the cascading failures caused by cyberattacks(CFCAs)in real time and reduce their damage on cyber-physical power systems(CPPSs),a novel early warning method based on attack gains and cost principle(AGCP)is proposed.Firstly,according to the CFCA characteristics,the leading role of attackers in the whole evolutionary process is discussed.The breaking out of a CFCA is deduced based on the AGCP from the view of attackers,and the priority order of all CFCAs is then provided.Then,the method to calculate the probability of CFCAs is proposed,and an early warning model for CFCA is designed.Finally,to verify the effectiveness of this method,a variety of CFCAs are simulated in a local CPPS model based on the IEEE 39-bus system.The experimental results demonstrate that this method can be used as a reliable assistant analysis technology to facilitate early warning of CFCAs.
文摘[Objective] The paper was to investigate the effects of adding Shuanghuanglian propolis oral liquid in drinking water on growth performance,slaughter performance and meat quality of broilers. [Method]Ninety one-day-old broilers were randomly divided into three groups（ group Ⅰ,group Ⅱ and group Ⅲ） ： group Ⅰ was the control group,and groups Ⅱ and Ⅲ were added 0. 5 and 1. 0 mL / L Shuanghuanglian propolis oral liquid in drinking water,respectively.[Result] Compared with broilers in group I,the average daily feed intakes of broilers in group Ⅱ and group Ⅲ were increased by 0. 86%（ P 〉 0. 05） and 1. 10%（ P 〉 0. 05）,respectively; the average daily gains were increased by 2. 33%（ P 〈 0. 05） and 4. 43%（ P 〈 0. 05）,respectively; the feed gain ratios were decreased by 1. 05%（ P 〉0. 05） and 2. 63%（ P 〈0. 05）,respectively; the slaughter rates were increased by 0. 94%（ P 〉0. 05） and 1. 70%（ P 〈0. 05）,respectively; the eviscerated rates were increased by 0. 52%（ P 〉 0. 05） and 1. 15%（ P 〉 0. 05）,respectively; the semi-eviscerated rates were increased by 1. 51%（ P 〈 0. 05） and 2.23%（ P 〈 0. 05）,respectively; the breast muscle rates were increased by 3. 77%（ P 〈 0. 05） and 5. 51%（ P 〈 0. 05）,respectively; the leg muscle rates were increased by 1. 96%（ P 〉 0. 05） and 4. 09%（ P 〈 0. 05）,respectively; the lightness（ L＊） were decreased by 0. 96%（ P 〉 0. 05） and 1. 47%（ P 〉 0. 05）,respectively; the redness（ a＊） were increased by 1. 24%（ P 〈 0. 05） and 1. 86%（ P 〈 0. 05）,respectively; the yellowness（ b＊） were decreased by 0. 44%（ P 〉0. 05） and 1. 03%（ P 〈0. 05）,respectively; the drip losses were decreased by 1. 22%（ P 〈0. 05） and 1. 56%（ P 〈0. 05）,respectively; the cooking losses were decreased by 1. 76%（ P 〉 0. 05） and 2. 89%（ P 〈 0. 05）,respectively. [Conclusion]Adding 0. 5 and 1. 0 mL / L Shuanghuanglian propolis oral liquid in drinking wa
基金funded by the Program for Public–Welfare Forestry of the State Forestry Administration of China(Grant No.201104008)
文摘Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relating to forest types, and estimated the total tree biomass carbon stocks and projected gains through natural stand development by 2020 and 2050 in the Daqing Mountain Nature Reserve based on Category II data of the Forest Inventory of Inner Mongolia for the period ending 2008. Over a total area of 388,577 ha,this nature reserve currently stores an estimated 2221 Gg C in tree aboveground biomass alone, with potential to grow by more than 30 % to reach 2938 Gg C by 2020 and nearly double to 4092 Gg C by 2050 through natural development of the existing forest stands. The tree biomass carbon density and potential gain in tree biomass carbon stocks vary markedly among forest types and with stand development.The variations in the potential change of tree biomass carbon density for the periods 2008–2020 and 2008–2050 among forest types partly reflect the varying relationships of tree biomass carbon density with stand age for different tree species, and partly are attributable to variations in the stand age structure among different forest types. Of the major forest types, the ranking of projected changes in tree biomass carbon density are not consistent with variations in the relationship between tree biomass carbon density and stand age, neither are they explainable by variations in stand age structures, implying the interactive effect between forest type and stand dynamics on temporal changes in tree biomass carbon density. Birch rank highest for future biomass carbon sequestration because of its dominance in cover area and better age structure for potential gain in tree biomass carbon stocks. Poplar and larch were out-performers compared to other forest types given their greater contribution to total tree biomass carbon stocks relative to their distributional areas. Findings in this study illustrate th
