Climate change poses substantial challenges to agricultural productivity and sustainability,particularly in Mediterranean and Sub-Saharan Africa regions.Local smallholder farmers’adaptation strategies to climate chan...Climate change poses substantial challenges to agricultural productivity and sustainability,particularly in Mediterranean and Sub-Saharan Africa regions.Local smallholder farmers’adaptation strategies to climate change are crucial for mitigating these impacts.Therefore,this study investigated the socioeconomic factors influencing smallholder farmers’perceptions and adaptation strategies to climate change in four countries(Morocco,Egypt,Italy,and Senegal)of Mediterranean and Sub-Saharan Africa regions using a binary logistic regression(BLR)model.The results indicated that educational level,farming experience,agricultural income,farm size,participation in agricultural workshops,and training in Good Agricultural Practices(GAPs)significantly impacted smallholder farmers’perceptions and adaptation strategies to climate change(such as smallholder farmers adopting drought-tolerant crops).Higher educational level was linked to the greater possibility of smallholder farmers adopting drought-tolerant crops in Italy and Egypt,while gaps in rural education limited the possibility of smallholder farmers adopting drought-tolerant crops in Morocco and Senegal.Farming experience and agricultural income also enhanced the possibility of smallholder farmers adopting drought-tolerant crops,with notable variations across countries due to systemic barriers such as limited infrastructure in Senegal.Larger farm size and participation in agricultural workshops further improved the possibility of smallholder farmers adopting drought-tolerant crops,particularly in Morocco and Egypt.The findings highlighted the importance of tailored interventions and policy measures to support smallholder farmers in effectively responding to the challenges of climate change under diverse agricultural contexts.By understanding the specific needs and circumstances of smallholder farmers in these countries,policymakers can develop more effective adaptation strategies to enhance agricultural resilience and sustainability under the context of climate change.展开更多
提出了一种在卫星与地面移动系统综合环境下的位置管理方案,即把两系统相重叠的小区设置为边界位置区(BLA),漫游用户在 BLA 中进行位置更新,呼叫到达时,BLA 中的位置寄存器配合系统进行寻呼。通过计算和数值分析证明该方案不仅可以使原...提出了一种在卫星与地面移动系统综合环境下的位置管理方案,即把两系统相重叠的小区设置为边界位置区(BLA),漫游用户在 BLA 中进行位置更新,呼叫到达时,BLA 中的位置寄存器配合系统进行寻呼。通过计算和数值分析证明该方案不仅可以使原有两系统结构不发生变化,并且能有效减小位置更新与寻呼造成的系统开销。展开更多
Caisson breakwaters are mainly constructed in deep waters to protect an area against waves.These breakwaters are con-ventionally designed based on the concept of the safety factor.However,the wave loads and resistance...Caisson breakwaters are mainly constructed in deep waters to protect an area against waves.These breakwaters are con-ventionally designed based on the concept of the safety factor.However,the wave loads and resistance of structures have epistemic or aleatory uncertainties.Furthermore,sliding failure is one of the most important failure modes of caisson breakwaters.In most previous studies,for assessment purposes,uncertainties,such as wave and wave period variation,were ignored.Therefore,in this study,Bayesian reliability analysis is implemented to assess the failure probability of the sliding of Tombak port breakwater in the Persian Gulf.The mean and standard deviations were taken as random variables to consider dismissed uncertainties.For this purpose,the frst-order reliability method(FORM)and the frst principal curvature cor-rection in FORM are used to calculate the reliability index.The performances of these methods are verifed by importance sampling through Monte Carlo simulation(MCS).In addition,the reliability index sensitivities of each random variable are calculated to evaluate the importance of diferent random variables while calculating the caisson sliding.The results show that the reliability index is most sensitive to the coefcients of friction,wave height,and caisson weight(or concrete density).The sensitivity of the failure probability of each of the random variables and their uncertainties are calculated by the derivative method.Finally,the Bayesian regression is implemented to predict the statistical properties of breakwater sliding with non-informative priors,which are compared to Goda’s formulation,used in breakwater design standards.The analysis shows that the model posterior for the sliding of a caisson breakwater has a mean and standard deviation of 0.039 and 0.022,respectively.A normal quantile analysis and residual analysis are also performed to evaluate the correctness of the model responses.展开更多
The present paper derives the modified expression of broad emission line profiles for the kinematic model of radiation pressure driving BLR gas outflow in the BLR, and discusses the intrinsic emission difference betwe...The present paper derives the modified expression of broad emission line profiles for the kinematic model of radiation pressure driving BLR gas outflow in the BLR, and discusses the intrinsic emission difference between the two lines HeIλ5876 and Hβ. It is shown that the fact that the observed line width of HeIλ5876 is broader than that of Hβ cannot be explained by W. G. Mathews’ modified model. For comparison, line profiles of gravitational infall model and orbital disk model are also calculated; the latter is in good agreement with the observations. Thereupon, conclusion is reached that gravitational infall is an important process in the BLR gas motion.展开更多
Several proposed assemble algorithms for Optical Burst Switching (OBS) network is described, and the feature relative merits is discussed and analyzed in this paper. The authors propose an assembly mechanism FAT where...Several proposed assemble algorithms for Optical Burst Switching (OBS) network is described, and the feature relative merits is discussed and analyzed in this paper. The authors propose an assembly mechanism FAT where time threshold is fluctuating randomly to reduce continuous blocking rate. With network simulation, the basic performance of these assembly schemes is compared and analyzed. The results show that burst loss ratio and assembly delay of the proposed FAT mechanism is better than that of exist assemble mechanism.展开更多
In the framework of BLR in AGNs, i.e. large number of small, cold and dense emission-line clouds immerging in an intercloud hot medium, a delicate radiation model for a typical emission cloud is established, in which ...In the framework of BLR in AGNs, i.e. large number of small, cold and dense emission-line clouds immerging in an intercloud hot medium, a delicate radiation model for a typical emission cloud is established, in which the backside photoionization of the cloud against the central continuum source by the scattered diffuse continuum in the hot medium is considered. Under the assumption of the radial kinematics of the BLR clouds, the line profiles for the two important UV emission-lines, Lya and CIV/11549 are computed; and based on these calculations, various physical factors that affect the properties of the emission-line profiles are discussed. It is concluded that: (i) when the BLR clouds is inflow, there exists a confining hot medium with density around 2 x 105 cm-3. In this case, theoretical line profiles agree well with the observational; (ii) both symmetric Lya and nearly symmetric CIV line profiles show blue velocity shifts, the quantities of which are sensitive to the cutoff of the outer radius of the BLR. It is suggested that this cutoff effect is physical background to explain the observations that high ionization lines in the spectra of AGNs have some systematic blue shifts relative to those low ionization lines which usually characterize their source system velocities.展开更多
基金an integral component of the TRUSTFARM Project,supported by the European Union’s Horizon 2020 research and innovation programThe TRUSTFARM Project was carried out under the European Research Area Network Cofund on Food Systems and Climate(ERA-NET FOSC,862555)+1 种基金built upon and supported by the experience from the Joint Programming Initiative on Agriculture,Food Security&Climate Change(FACCE-JPI)the European Research Area Network Cofund on Long-term Europe-Africa Partnership on Agricultural Research for Development(LEAP-Agri).
文摘Climate change poses substantial challenges to agricultural productivity and sustainability,particularly in Mediterranean and Sub-Saharan Africa regions.Local smallholder farmers’adaptation strategies to climate change are crucial for mitigating these impacts.Therefore,this study investigated the socioeconomic factors influencing smallholder farmers’perceptions and adaptation strategies to climate change in four countries(Morocco,Egypt,Italy,and Senegal)of Mediterranean and Sub-Saharan Africa regions using a binary logistic regression(BLR)model.The results indicated that educational level,farming experience,agricultural income,farm size,participation in agricultural workshops,and training in Good Agricultural Practices(GAPs)significantly impacted smallholder farmers’perceptions and adaptation strategies to climate change(such as smallholder farmers adopting drought-tolerant crops).Higher educational level was linked to the greater possibility of smallholder farmers adopting drought-tolerant crops in Italy and Egypt,while gaps in rural education limited the possibility of smallholder farmers adopting drought-tolerant crops in Morocco and Senegal.Farming experience and agricultural income also enhanced the possibility of smallholder farmers adopting drought-tolerant crops,with notable variations across countries due to systemic barriers such as limited infrastructure in Senegal.Larger farm size and participation in agricultural workshops further improved the possibility of smallholder farmers adopting drought-tolerant crops,particularly in Morocco and Egypt.The findings highlighted the importance of tailored interventions and policy measures to support smallholder farmers in effectively responding to the challenges of climate change under diverse agricultural contexts.By understanding the specific needs and circumstances of smallholder farmers in these countries,policymakers can develop more effective adaptation strategies to enhance agricultural resilience and sustainability under the context of climate change.
文摘提出了一种在卫星与地面移动系统综合环境下的位置管理方案,即把两系统相重叠的小区设置为边界位置区(BLA),漫游用户在 BLA 中进行位置更新,呼叫到达时,BLA 中的位置寄存器配合系统进行寻呼。通过计算和数值分析证明该方案不仅可以使原有两系统结构不发生变化,并且能有效减小位置更新与寻呼造成的系统开销。
文摘Caisson breakwaters are mainly constructed in deep waters to protect an area against waves.These breakwaters are con-ventionally designed based on the concept of the safety factor.However,the wave loads and resistance of structures have epistemic or aleatory uncertainties.Furthermore,sliding failure is one of the most important failure modes of caisson breakwaters.In most previous studies,for assessment purposes,uncertainties,such as wave and wave period variation,were ignored.Therefore,in this study,Bayesian reliability analysis is implemented to assess the failure probability of the sliding of Tombak port breakwater in the Persian Gulf.The mean and standard deviations were taken as random variables to consider dismissed uncertainties.For this purpose,the frst-order reliability method(FORM)and the frst principal curvature cor-rection in FORM are used to calculate the reliability index.The performances of these methods are verifed by importance sampling through Monte Carlo simulation(MCS).In addition,the reliability index sensitivities of each random variable are calculated to evaluate the importance of diferent random variables while calculating the caisson sliding.The results show that the reliability index is most sensitive to the coefcients of friction,wave height,and caisson weight(or concrete density).The sensitivity of the failure probability of each of the random variables and their uncertainties are calculated by the derivative method.Finally,the Bayesian regression is implemented to predict the statistical properties of breakwater sliding with non-informative priors,which are compared to Goda’s formulation,used in breakwater design standards.The analysis shows that the model posterior for the sliding of a caisson breakwater has a mean and standard deviation of 0.039 and 0.022,respectively.A normal quantile analysis and residual analysis are also performed to evaluate the correctness of the model responses.
基金Project supported by the National Natural Science Foundation of China
文摘The present paper derives the modified expression of broad emission line profiles for the kinematic model of radiation pressure driving BLR gas outflow in the BLR, and discusses the intrinsic emission difference between the two lines HeIλ5876 and Hβ. It is shown that the fact that the observed line width of HeIλ5876 is broader than that of Hβ cannot be explained by W. G. Mathews’ modified model. For comparison, line profiles of gravitational infall model and orbital disk model are also calculated; the latter is in good agreement with the observations. Thereupon, conclusion is reached that gravitational infall is an important process in the BLR gas motion.
基金ThisresearchwassupportedbytheNationalOutstandingYouthFoundation(No .6 0 32 510 4 ) National 86 3KeyProject (No .2 0 0 2AA12 2 0 2 2 ) theGrandKeyscienceandTechnologyResearchProgramofMOE (No .0 2 15)
文摘Several proposed assemble algorithms for Optical Burst Switching (OBS) network is described, and the feature relative merits is discussed and analyzed in this paper. The authors propose an assembly mechanism FAT where time threshold is fluctuating randomly to reduce continuous blocking rate. With network simulation, the basic performance of these assembly schemes is compared and analyzed. The results show that burst loss ratio and assembly delay of the proposed FAT mechanism is better than that of exist assemble mechanism.
基金Project supported by Pangden Project FoundationNational Natural Science Foundation of China.
文摘In the framework of BLR in AGNs, i.e. large number of small, cold and dense emission-line clouds immerging in an intercloud hot medium, a delicate radiation model for a typical emission cloud is established, in which the backside photoionization of the cloud against the central continuum source by the scattered diffuse continuum in the hot medium is considered. Under the assumption of the radial kinematics of the BLR clouds, the line profiles for the two important UV emission-lines, Lya and CIV/11549 are computed; and based on these calculations, various physical factors that affect the properties of the emission-line profiles are discussed. It is concluded that: (i) when the BLR clouds is inflow, there exists a confining hot medium with density around 2 x 105 cm-3. In this case, theoretical line profiles agree well with the observational; (ii) both symmetric Lya and nearly symmetric CIV line profiles show blue velocity shifts, the quantities of which are sensitive to the cutoff of the outer radius of the BLR. It is suggested that this cutoff effect is physical background to explain the observations that high ionization lines in the spectra of AGNs have some systematic blue shifts relative to those low ionization lines which usually characterize their source system velocities.
