Male allocare among nonhuman primates has frequently been investigated from the perspective of the caretaker. Here we examined whether male allocare relates to environmental factors or the females＇ energetic stress. ...Male allocare among nonhuman primates has frequently been investigated from the perspective of the caretaker. Here we examined whether male allocare relates to environmental factors or the females＇ energetic stress. We researched the possible differences of allocare between sexes in free-ranging black-and-white snub-nosed monkeys （Rhinopithecus bieti） in Tibet. A combination of stepwise least squares regression analysis was used to identify the influence of ecological factors （temperature, rainfall, etc.） and infant age that best account for seasonal variation of allocare. The results indicate, except for the functions of infant age, however, that male allocare is a negative function of temperature and female allocare is a positive function of temperature. Specifically, we tested the energetic stress hypothesis, which predicts that the energetic burden of females in a severe environment favour an increased rate of male allocare during the seasons of high energetic stress. We analyzed the allocare difference between high energetic stress season （Mar - Apr）, when temperature was low, food availability was scarce, and infants were young, and low energetic stress season （Jun - Aug）, based on data obtained during June 2003 - June 2004. Our results supported the energetic stress hypothesis because male allocare in high energetic stress season was higher than that of in low energetic stress season and female allocate was reverse. Therefore, we propose it is the energetic stress on female that make male allocare possible. Male take these interests for other aims and meet some functional hypothesis, which are addressed from the perspective of the male.展开更多
Based on the single-chain structure model of magnetorheological fluids, a formu la for the calculation of shear stresses was established. The interaction force of two magnetic particles in an infinite single-chain wa...Based on the single-chain structure model of magnetorheological fluids, a formu la for the calculation of shear stresses was established. The interaction force of two magnetic particles in an infinite single-chain was deduced using a new theoretical model which is founded on Ampere' molecular curr ent hypothesis, dipole theory and Ampere' law. Furthermore, the resultant force on a particle was then deduced by taking into account of the action caused by al l the other particles in the single-chain. A predictive formula for shear stres ses was made corresponding to the case that MR fluids were sheared by a small an gle and the calculating results fit well on the order with the yield stresses of the commercial MR fluids.展开更多
在控制环境因子和遗传因子的条件下,以白花泡桐、毛泡桐、毛泡桐×白花泡桐和白花泡桐×毛泡桐的无性系为材料,运用物候学观察、杂交试验、树木逆境生理学试验、引种试验和反证法证明的方法研究了泡桐假二叉分枝机理。结果表明...在控制环境因子和遗传因子的条件下,以白花泡桐、毛泡桐、毛泡桐×白花泡桐和白花泡桐×毛泡桐的无性系为材料,运用物候学观察、杂交试验、树木逆境生理学试验、引种试验和反证法证明的方法研究了泡桐假二叉分枝机理。结果表明:冬季的低温胁迫和水分胁迫单独或共同的作用导致泡桐顶芽死亡。初步提出"低温—水分胁迫假说"(The hypothesis of low-temperature stress and water stress)作为泡桐假二叉分枝机理的理论解释。展开更多
基金The Innovation Project of the Chinese Academy of Sciences(grants KSCX2-1-03,KSCX2-1-09)the National Natural Science Foundation of China(30870375)~~
文摘Male allocare among nonhuman primates has frequently been investigated from the perspective of the caretaker. Here we examined whether male allocare relates to environmental factors or the females＇ energetic stress. We researched the possible differences of allocare between sexes in free-ranging black-and-white snub-nosed monkeys （Rhinopithecus bieti） in Tibet. A combination of stepwise least squares regression analysis was used to identify the influence of ecological factors （temperature, rainfall, etc.） and infant age that best account for seasonal variation of allocare. The results indicate, except for the functions of infant age, however, that male allocare is a negative function of temperature and female allocare is a positive function of temperature. Specifically, we tested the energetic stress hypothesis, which predicts that the energetic burden of females in a severe environment favour an increased rate of male allocare during the seasons of high energetic stress. We analyzed the allocare difference between high energetic stress season （Mar - Apr）, when temperature was low, food availability was scarce, and infants were young, and low energetic stress season （Jun - Aug）, based on data obtained during June 2003 - June 2004. Our results supported the energetic stress hypothesis because male allocare in high energetic stress season was higher than that of in low energetic stress season and female allocate was reverse. Therefore, we propose it is the energetic stress on female that make male allocare possible. Male take these interests for other aims and meet some functional hypothesis, which are addressed from the perspective of the male.
基金Funded by the"863"Hi tech Research and Development Program of China(No.2001AA33P020)
文摘Based on the single-chain structure model of magnetorheological fluids, a formu la for the calculation of shear stresses was established. The interaction force of two magnetic particles in an infinite single-chain was deduced using a new theoretical model which is founded on Ampere' molecular curr ent hypothesis, dipole theory and Ampere' law. Furthermore, the resultant force on a particle was then deduced by taking into account of the action caused by al l the other particles in the single-chain. A predictive formula for shear stres ses was made corresponding to the case that MR fluids were sheared by a small an gle and the calculating results fit well on the order with the yield stresses of the commercial MR fluids.
文摘在控制环境因子和遗传因子的条件下,以白花泡桐、毛泡桐、毛泡桐×白花泡桐和白花泡桐×毛泡桐的无性系为材料,运用物候学观察、杂交试验、树木逆境生理学试验、引种试验和反证法证明的方法研究了泡桐假二叉分枝机理。结果表明:冬季的低温胁迫和水分胁迫单独或共同的作用导致泡桐顶芽死亡。初步提出"低温—水分胁迫假说"(The hypothesis of low-temperature stress and water stress)作为泡桐假二叉分枝机理的理论解释。
