The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates （e.g., lower and upper limits of ...The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates （e.g., lower and upper limits of metabolic power output） present a method for elucidating the effects of ecological and evolutionary factors on the interface between physiology and life history in birds. In this paper we review variation in avian metabolic rates [basal metabolic rate （BMR; minimum normothermic metabolic rate）, summit metabolic rate （Msum; maximal thermoregulatory metabolic rate）, and maximal metabolic rate （MMR; maximal exercise metabolic rate）], the factors associated with this variation, the evidence for functional links between these metabolic traits, and the ecological and evolutionary significance of avian metabolic diversity. Both lower and upper limits to metabolic power production are phenotypically flexible traits, and vary in association with numerous ecological and evolutionary factors. For both inter- and intraspecific comparisons, lower and upper limits to metabolic power production are generally upregulated in response to energetically demanding conditions and downregulated when energetic demands are relaxed, or under conditions of energetic scarcity. Positive correlations have been documented between BMR, Msum and MMR in some, but not all studies on birds, providing partial support for the idea of a functional link between lower and upper limits to metabolic power production, but more intraspecific studies are needed to determine the robustness of this conclusion. Correlations between BMR and field metabolic rate （or daily energy expenditure） in birds are variable, suggesting that the linkage between these traits is subject to behavioral adjustment, and studies of the relationship between field and maximal metabolic rates are lacking. Our understanding of avian metabolic diversity would benefit from future studies of： （1） the functional and mechanistic links between lower and upper limits of metabolic power output; （2） the environmental and ecological cues driving phenotypically flexible metabolic responses, and how responses to such cues might impact population responses to climate change; （3） the shapes of metabolic reaction norms and their association with environmental variability; and （4） the relationship of metabolic variation to fitness, including studies of repeatability and heritability of minimum and maximum metabolic power output [Current Zoology 56 （6）： 741-758, 2010].展开更多
Many image inverse problems are ill-posed for no unique solutions. Most of them have incommensurable or mixed-type objectives. In this study, a multi-objective optimization framework is introduced to model such ill-po...Many image inverse problems are ill-posed for no unique solutions. Most of them have incommensurable or mixed-type objectives. In this study, a multi-objective optimization framework is introduced to model such ill-posed inverse problems. The conflicting objectives are designed according to the properties of ill-posedness and certain techniques. Multi-objective evolutionary algorithms have capability to optimize multiple objectives simultaneously and obtain a set of trade-off solutions. For that reason, we use multi-objective evolutionary algorithms to keep the trade-off between these objectives for image ill-posed problems. Two case studies of sparse reconstruction and change detection are imple- mented. In the case study of sparse reconstruction, the measurement error term and the sparsity term are optimized by multi-objective evolutionary algorithms, which aims at balancing the trade-off between enforcing sparsity and reducing measurement error. In the case study of image change detection, two conflicting objectives are constructed to keep the trade-off between robustness to noise and preserving the image details. Experimental results of the two case studies confirm the multi-objective optimization framework for ill-posed inverse problems in image processing is effective.展开更多
Light is a fundamental source of energy but is also potentially harmful to organisms. Plants have evolved a variety of regulatory mechanisms to respond to the naturally varying light conditions. Xanthophyll cycle is n...Light is a fundamental source of energy but is also potentially harmful to organisms. Plants have evolved a variety of regulatory mechanisms to respond to the naturally varying light conditions. Xanthophyll cycle is now recognized as a key regulator and photoprotective mechanism found ubiquitously in plants. Xanthophyll cycle has multiple functions, such as thermal dissipation, protection against oxidative stress caused by light, modulation of the structure of thylakoid membrane, involving in blue light signal transduction and regulating the synthesis ofABA （Abscisic acid）. VDE （Violaxanth de-epoxidase） and ZE （zeaxanth epoxidase）, are involved in xanthophyll cycle. This paper outlined the functions of xanthophylls cycle and its relative enzymes.展开更多
Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs However during migration, these birds often have to cross water surfaces where thermal currents ...Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs However during migration, these birds often have to cross water surfaces where thermal currents are weak; during these times, birds mainly use flapping （powered） flight which increases energy consumption and mortality risk. As a result, some species have evolved strategies to reduce the amount of time spent over water by taking extensive detours over land. In this paper, we con- ducted a meta-analysis of water-crossing tendencies in Afro-Palearctic migrating raptors in relation to their morphology, their flight performance, and their phylogenetic relationships. In particular, we considered the aspect ratio （calculated as the wing span squared divided by wing area）, the energetic cost of powered flight, and the maximum water crossing length regularly performed by adult birds. Our results suggest that energy consumption during powered flight predominately affects the ability of raptors to fly over water surfaces展开更多
Dark energy and dark matter are only indirectly measured though their gravitational effects.It is possibie that there is some direct,non-gravitational interaction between DE and DM,which can be used to solve(or,at lea...Dark energy and dark matter are only indirectly measured though their gravitational effects.It is possibie that there is some direct,non-gravitational interaction between DE and DM,which can be used to solve(or,at least alleviate)several important theoretical problems.In the present work,by analysing the cosmological dynamical system with a dark-sector interaction which changes its sign during the cosmological evolution,we find a scaling attractor to help to alleviate the cosmic-coincidence problem.This result shows that this interaction can bring new features to the cosmology.展开更多
In this work, a novel morphing machining strategy （MMS） is proposed. In the method, the workpiece is progressively carved out from the stock. Pitfalls in conventional iso-height strategy, such as sharp edges and une...In this work, a novel morphing machining strategy （MMS） is proposed. In the method, the workpiece is progressively carved out from the stock. Pitfalls in conventional iso-height strategy, such as sharp edges and unevenly distributed left-over materials, are overcome. Moreover, to calculate different levels in the MMS, an energy-based morphing algorithm is proposed. Finally, the proposed strategy is employed in the machining of artificial bone represented by a T-spline surface. The excellent properties of T-spline, such as expressing complex shapes with a single surface, have been well adopted to artificial bone fabri- cation. Computer simulation and the actual machining of the middle finger bone show the feasibility of the proposed strategy.展开更多
文摘The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates （e.g., lower and upper limits of metabolic power output） present a method for elucidating the effects of ecological and evolutionary factors on the interface between physiology and life history in birds. In this paper we review variation in avian metabolic rates [basal metabolic rate （BMR; minimum normothermic metabolic rate）, summit metabolic rate （Msum; maximal thermoregulatory metabolic rate）, and maximal metabolic rate （MMR; maximal exercise metabolic rate）], the factors associated with this variation, the evidence for functional links between these metabolic traits, and the ecological and evolutionary significance of avian metabolic diversity. Both lower and upper limits to metabolic power production are phenotypically flexible traits, and vary in association with numerous ecological and evolutionary factors. For both inter- and intraspecific comparisons, lower and upper limits to metabolic power production are generally upregulated in response to energetically demanding conditions and downregulated when energetic demands are relaxed, or under conditions of energetic scarcity. Positive correlations have been documented between BMR, Msum and MMR in some, but not all studies on birds, providing partial support for the idea of a functional link between lower and upper limits to metabolic power production, but more intraspecific studies are needed to determine the robustness of this conclusion. Correlations between BMR and field metabolic rate （or daily energy expenditure） in birds are variable, suggesting that the linkage between these traits is subject to behavioral adjustment, and studies of the relationship between field and maximal metabolic rates are lacking. Our understanding of avian metabolic diversity would benefit from future studies of： （1） the functional and mechanistic links between lower and upper limits of metabolic power output; （2） the environmental and ecological cues driving phenotypically flexible metabolic responses, and how responses to such cues might impact population responses to climate change; （3） the shapes of metabolic reaction norms and their association with environmental variability; and （4） the relationship of metabolic variation to fitness, including studies of repeatability and heritability of minimum and maximum metabolic power output [Current Zoology 56 （6）： 741-758, 2010].
基金This work was supported by the National Natural Science Foundation of China （Grant no. 61273317 and 61422209）, the National Top Youth Talents Program of China, the Specialized Research Fund for the Doctoral Program of Higher Education （Grant no. 20130203110011） and the Fundamental Research Fund for the Central Universities （Grant no. K5051202053）.
文摘Many image inverse problems are ill-posed for no unique solutions. Most of them have incommensurable or mixed-type objectives. In this study, a multi-objective optimization framework is introduced to model such ill-posed inverse problems. The conflicting objectives are designed according to the properties of ill-posedness and certain techniques. Multi-objective evolutionary algorithms have capability to optimize multiple objectives simultaneously and obtain a set of trade-off solutions. For that reason, we use multi-objective evolutionary algorithms to keep the trade-off between these objectives for image ill-posed problems. Two case studies of sparse reconstruction and change detection are imple- mented. In the case study of sparse reconstruction, the measurement error term and the sparsity term are optimized by multi-objective evolutionary algorithms, which aims at balancing the trade-off between enforcing sparsity and reducing measurement error. In the case study of image change detection, two conflicting objectives are constructed to keep the trade-off between robustness to noise and preserving the image details. Experimental results of the two case studies confirm the multi-objective optimization framework for ill-posed inverse problems in image processing is effective.
文摘Light is a fundamental source of energy but is also potentially harmful to organisms. Plants have evolved a variety of regulatory mechanisms to respond to the naturally varying light conditions. Xanthophyll cycle is now recognized as a key regulator and photoprotective mechanism found ubiquitously in plants. Xanthophyll cycle has multiple functions, such as thermal dissipation, protection against oxidative stress caused by light, modulation of the structure of thylakoid membrane, involving in blue light signal transduction and regulating the synthesis ofABA （Abscisic acid）. VDE （Violaxanth de-epoxidase） and ZE （zeaxanth epoxidase）, are involved in xanthophyll cycle. This paper outlined the functions of xanthophylls cycle and its relative enzymes.
文摘Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs However during migration, these birds often have to cross water surfaces where thermal currents are weak; during these times, birds mainly use flapping （powered） flight which increases energy consumption and mortality risk. As a result, some species have evolved strategies to reduce the amount of time spent over water by taking extensive detours over land. In this paper, we con- ducted a meta-analysis of water-crossing tendencies in Afro-Palearctic migrating raptors in relation to their morphology, their flight performance, and their phylogenetic relationships. In particular, we considered the aspect ratio （calculated as the wing span squared divided by wing area）, the energetic cost of powered flight, and the maximum water crossing length regularly performed by adult birds. Our results suggest that energy consumption during powered flight predominately affects the ability of raptors to fly over water surfaces
基金supported by the National Natural Science Foundation of China(Grant Nos.11147017 and 11347605)the"Applied Nonlinear Science and Technology of Zhejiang Province(Grant No.zx2012000070)the Ministry of Education Doctoral Program Funds(Grant No.20126101110004)
文摘Dark energy and dark matter are only indirectly measured though their gravitational effects.It is possibie that there is some direct,non-gravitational interaction between DE and DM,which can be used to solve(or,at least alleviate)several important theoretical problems.In the present work,by analysing the cosmological dynamical system with a dark-sector interaction which changes its sign during the cosmological evolution,we find a scaling attractor to help to alleviate the cosmic-coincidence problem.This result shows that this interaction can bring new features to the cosmology.
基金Project supported by the Science Fund for Creative Research Groups of National Natural Science Foundation of China （No. 51221004）, and the National Natural Science Foundation of Chi：na （Nos. 51175461 and 51105335）
文摘In this work, a novel morphing machining strategy （MMS） is proposed. In the method, the workpiece is progressively carved out from the stock. Pitfalls in conventional iso-height strategy, such as sharp edges and unevenly distributed left-over materials, are overcome. Moreover, to calculate different levels in the MMS, an energy-based morphing algorithm is proposed. Finally, the proposed strategy is employed in the machining of artificial bone represented by a T-spline surface. The excellent properties of T-spline, such as expressing complex shapes with a single surface, have been well adopted to artificial bone fabri- cation. Computer simulation and the actual machining of the middle finger bone show the feasibility of the proposed strategy.
