Abiotic stresses and soil nutrient limitations are major environmental conditions that reduce plant growth,productivity and quality.Plants have evolved mechanisms to perceive these environmental challenges,transmit th...Abiotic stresses and soil nutrient limitations are major environmental conditions that reduce plant growth,productivity and quality.Plants have evolved mechanisms to perceive these environmental challenges,transmit the stress signals within cells as well as between cells and tissues,and make appropriate adjustments in their growth and development in order to survive and reproduce.In recent years,significant progress has been made on many fronts of the stress signaling research,particularly in understanding the downstream signaling events that culminate at the activation of stress-and nutrient limitation-responsive genes,cellular ion homeostasis,and growth adjustment.However,the revelation of the early events of stress signaling,particularly the identification of primary stress sensors,still lags behind.In this review,we summarize recent work on the genetic and molecular mechanisms of plant abiotic stress and nutrient limitation sensing and signaling and discuss new directions for future studies.展开更多
In order to improve the energy efficiency(EE)in cognitive radio(CR),this paper investigates the joint design of cooperative spectrum sensing time and the power control optimization problem for the secondary user syste...In order to improve the energy efficiency(EE)in cognitive radio(CR),this paper investigates the joint design of cooperative spectrum sensing time and the power control optimization problem for the secondary user systems to achieve the maximum energy efficiency in a cognitive network based on hybrid spectrum sharing,meanwhile considering the maximum transmit power,user quality of service(QoS)requirements,interference limitations,and primary user protection.The optimization of energy efficient sensing time and power allocation is formulated as a non-convex optimization problem.The Dinkelbach’s method is adopted to solve this problem and to transform the non-convex optimization problem in fractional form into an equivalent optimization problem in the form of subtraction.Then,an iterative power allocation algorithm is proposed to solve the optimization problem.The simulation results show the effectiveness of the proposed algorithms for energy-efficient resource allocation in the cognitive network.展开更多
Optimal plant development requires root uptake of 14 essential mineral elements from the soil.Since the bioavailability of these nutrients underlies large variation in space and time,plants must dynamically adjust the...Optimal plant development requires root uptake of 14 essential mineral elements from the soil.Since the bioavailability of these nutrients underlies large variation in space and time,plants must dynamically adjust their root architecture to optimize nutrient access and acquisition.The information on external nutrient availability and whole-plant demand is translated into cellular signals that often involve phytohormones as intermediates to trigger a systemic or locally restricted developmental response.Timing and extent of such local root responses depend on the overall nutritional status of the plant that is transmitted from shoots to roots in the form of phytohormones or other systemic long-distance signals.The integration of these systemic and local signals then determines cell division or elongation rates in primary and lateral roots,the initiation,emergence,or elongation of lateral roots,as well as the formation of root hairs.Here,we review the cascades of nutrient-related sensing and signaling events that involve hormones and highlight nutrient-hormone relations that coordinate root developmental plasticity in plants.展开更多
协作频谱感知是认知无线电网络的基础和关键阶段,频谱检测过程中的节点分配策略将直接决定联合频谱感知的结果。介绍了多种分配认知终端的方法,旨在提高频谱感知的效率和公平性。针对不同子频带的感知效率,提出了一种称为由频点占用导...协作频谱感知是认知无线电网络的基础和关键阶段,频谱检测过程中的节点分配策略将直接决定联合频谱感知的结果。介绍了多种分配认知终端的方法,旨在提高频谱感知的效率和公平性。针对不同子频带的感知效率,提出了一种称为由频点占用导致的无效传输参数(inefficient transport parameter,ITP)指标来评估通信性能,给出了感知效率优化问题的闭式表达解,设计的场景包括终端对相同频带有不同的感知性能和相同的感知性能。针对不同子频带间的感知公平性,提出了两种分配算法:弓形分配算法和类划分分配算法。子频带间的公平性通过评估子带中最差的感知性能进行衡量。为了适用于实际场景,加入了频段属性参数来增强公平性,该参数考虑了主用户使用不同频段的优先级及抗干扰能力。仿真结果表明,所提出的策略显著改善了认知无线电网络中的ITP,特别是在子频带利用率不同的情况下,提出的弓形分配算法在公平性不明显降低的情况下,复杂度有明显改善。展开更多
This paper focuses on the energy efficiency of cognitive relay （CR） networks with cooperative sensing, joint optimization of the sensing time and the signal-to-noise ratio （SNR） is studied to maximize the energy e...This paper focuses on the energy efficiency of cognitive relay （CR） networks with cooperative sensing, joint optimization of the sensing time and the signal-to-noise ratio （SNR） is studied to maximize the energy efficiency of CR network. Theoretical analysis shows that there exists an optimal sensing time and optimal SNR to make the energy efficiency maximized under a constraint of detection probability. Simulation results illustrate that the optimal fusion rule performs better than the OR rule and the AND rule in terms of the energy efficiency. By properly designing the fusion rule threshold as well as the number of cooperative sensing users, the energy efficiency of CR networks can be further improved.展开更多
文摘Abiotic stresses and soil nutrient limitations are major environmental conditions that reduce plant growth,productivity and quality.Plants have evolved mechanisms to perceive these environmental challenges,transmit the stress signals within cells as well as between cells and tissues,and make appropriate adjustments in their growth and development in order to survive and reproduce.In recent years,significant progress has been made on many fronts of the stress signaling research,particularly in understanding the downstream signaling events that culminate at the activation of stress-and nutrient limitation-responsive genes,cellular ion homeostasis,and growth adjustment.However,the revelation of the early events of stress signaling,particularly the identification of primary stress sensors,still lags behind.In this review,we summarize recent work on the genetic and molecular mechanisms of plant abiotic stress and nutrient limitation sensing and signaling and discuss new directions for future studies.
基金supported in part by the National Natural Science Foundation of China for Young Scholars under Grant No.61701167Young Elite Backbone Teachers in Blue and Blue Project of Jiangsu Province, China
文摘In order to improve the energy efficiency(EE)in cognitive radio(CR),this paper investigates the joint design of cooperative spectrum sensing time and the power control optimization problem for the secondary user systems to achieve the maximum energy efficiency in a cognitive network based on hybrid spectrum sharing,meanwhile considering the maximum transmit power,user quality of service(QoS)requirements,interference limitations,and primary user protection.The optimization of energy efficient sensing time and power allocation is formulated as a non-convex optimization problem.The Dinkelbach’s method is adopted to solve this problem and to transform the non-convex optimization problem in fractional form into an equivalent optimization problem in the form of subtraction.Then,an iterative power allocation algorithm is proposed to solve the optimization problem.The simulation results show the effectiveness of the proposed algorithms for energy-efficient resource allocation in the cognitive network.
基金Z.J.was supported by a fellowship(No.201406350062)from China Scholarship Council(CSC)This work was supported by the Deutsche For-schungsgemeinschaft with grants to N.v.W.(WI1728/25-1)and R.F.H.G.(HE 8362/1-1).
文摘Optimal plant development requires root uptake of 14 essential mineral elements from the soil.Since the bioavailability of these nutrients underlies large variation in space and time,plants must dynamically adjust their root architecture to optimize nutrient access and acquisition.The information on external nutrient availability and whole-plant demand is translated into cellular signals that often involve phytohormones as intermediates to trigger a systemic or locally restricted developmental response.Timing and extent of such local root responses depend on the overall nutritional status of the plant that is transmitted from shoots to roots in the form of phytohormones or other systemic long-distance signals.The integration of these systemic and local signals then determines cell division or elongation rates in primary and lateral roots,the initiation,emergence,or elongation of lateral roots,as well as the formation of root hairs.Here,we review the cascades of nutrient-related sensing and signaling events that involve hormones and highlight nutrient-hormone relations that coordinate root developmental plasticity in plants.
文摘协作频谱感知是认知无线电网络的基础和关键阶段,频谱检测过程中的节点分配策略将直接决定联合频谱感知的结果。介绍了多种分配认知终端的方法,旨在提高频谱感知的效率和公平性。针对不同子频带的感知效率,提出了一种称为由频点占用导致的无效传输参数(inefficient transport parameter,ITP)指标来评估通信性能,给出了感知效率优化问题的闭式表达解,设计的场景包括终端对相同频带有不同的感知性能和相同的感知性能。针对不同子频带间的感知公平性,提出了两种分配算法:弓形分配算法和类划分分配算法。子频带间的公平性通过评估子带中最差的感知性能进行衡量。为了适用于实际场景,加入了频段属性参数来增强公平性,该参数考虑了主用户使用不同频段的优先级及抗干扰能力。仿真结果表明,所提出的策略显著改善了认知无线电网络中的ITP,特别是在子频带利用率不同的情况下,提出的弓形分配算法在公平性不明显降低的情况下,复杂度有明显改善。
基金supported by the National Science Fund under Grant No. 6087215the Yunnan Research Program of Application Foundation under Grant No.2011FB035the School training fund under granted No.KKZ3201403010
文摘This paper focuses on the energy efficiency of cognitive relay （CR） networks with cooperative sensing, joint optimization of the sensing time and the signal-to-noise ratio （SNR） is studied to maximize the energy efficiency of CR network. Theoretical analysis shows that there exists an optimal sensing time and optimal SNR to make the energy efficiency maximized under a constraint of detection probability. Simulation results illustrate that the optimal fusion rule performs better than the OR rule and the AND rule in terms of the energy efficiency. By properly designing the fusion rule threshold as well as the number of cooperative sensing users, the energy efficiency of CR networks can be further improved.
