Long-distance migratory birds travel more rapidly in spring than in autumn,as they face temporal breeding constraints.However,several species travel slower in spring owing to environmental influences,such as food avai...Long-distance migratory birds travel more rapidly in spring than in autumn,as they face temporal breeding constraints.However,several species travel slower in spring owing to environmental influences,such as food availability and wind conditions.GPS trackers were attached to 17 Whooper Swans(Cygnus cygnus) inhabiting northeastern Mongolia,to determine their migration routes and stopover sites in spring and autumn.Differences between spring and autumn migrations,migration-influencing parameters,and the effect of spring stopover site temperatures were analyzed.Six swans completed perfect tours between their wintering and breeding sites,and these data were used for analysis.Spring migration lasted 57 days,with 49.2 days spent at 3.7 stopover sites.Autumn migration lasted 21.5 days,with 17.5 days spent at 1.0 stopover sites.Thus,the swans traveled more rapidly in autumn than in spring.Migration distance,number of stopovers,migration speed,and straightness were important migration determinants in both spring and autumn.Migration distance,stopover duration,number of stopovers,daily travel speed,travel duration,and migration speed differed significantly between spring and autumn.During spring migration,the temperature at the current stopover sites and that at the future stopover sites displayed significant variations(t=1585.8,df=631.6,p <0.001).These findings are critical for the conservation and management of Whooper Swans and their key habitats in East Asian regions,and the data are anticipated to make a particularly significant contribution toward developing detailed management plans for the conservation of their key habitats.展开更多
Intrinsic attenuation of the earth causes energy loss and phase distortion in seismic wave propagation.To obtain high-resolution imaging results,these negative effects must be considered during reverse time migration(...Intrinsic attenuation of the earth causes energy loss and phase distortion in seismic wave propagation.To obtain high-resolution imaging results,these negative effects must be considered during reverse time migration(RTM).We can easily implement attenuation-compensated RTM using the constant Q viscoacoustic wave equation with decoupled amplitude attenuation and phase dispersion terms.However,the nonphysical amplitude-compensation process will inevitably amplify the high-frequency noise in the wavefield in an exponential form,causing the numerical simulation to become unstable.This is due to the fact that the amplitude of the compensation grows exponentially with frequency.In order to achieve stable attenuation-compensated RTM,we modify the analytic expression of the attenuation compensation extrapolation operator and make it only compensate for amplitude loss within the effective frequency band.Based on this modified analytic formula,we then derive an explicit time-space domain attenuation compensation extrapolation operator.Finally,the implementation procedure of stable attenuation-compensated RTM is presented.In addition to being simple to implement,the newly proposed attenuation-compensated extrapolation operator is superior to the conventional low-pass filter in suppressing random noise,which will further improve the imaging resolution.We use two synthetic and one land seismic datasets to verify the stability and effectiveness of the proposed attenuationcompensated RTM in improving imaging resolution in viscous media.展开更多
Background:While the general migration routes of most waders are known,details concerning connectivity between breeding grounds, stopover sites and wintering grounds are often lacking.Such information is critical from...Background:While the general migration routes of most waders are known,details concerning connectivity between breeding grounds, stopover sites and wintering grounds are often lacking.Such information is critical from the conservation perspective and necessary for understanding the annual cycle.Studies are especially needed to identify key stopover sites in remote regions. Using satellite transmitters, we traced spring and autumn migration routes and connectivity of Grey Plovers on the East Atlantic Flyway.Our findings also revealed the timing,flight speed, and duration of migrations. Methods:We used ARGOS satellite transmitters to track migration routes of 11 Grey Plovers that were captured at the German Wadden Sea where they had stopped during migration.Birds were monitored for up to 3 years,2011-2014.Results:Monitoring signals indicated breeding grounds in the Taimyr and Yamal regions;important staging sites on the coasts of the southern Pechora Sea and the Kara Sea;and wintering areas that ranged from NW-Ireland to Guinea Bissau.The average distance traveled from wintering grounds to breeding grounds was 5534 km. Migration duration varied between 42 and 152 days;during this period birds spent about 95% of the time at staging sites.In spring most plovers crossed inland Eastern Europe, whereas in autumn most followed the coastline.Almost all of the birds departed during favorable wind conditions within just 4 days (27-30 May) on northward migration from the Wadden Sea.In spring birds migrated significantly faster between the Wadden Sea and the Arctic than on return migration in autumn (12 vs.37 days),with shorter stopovers during the northward passage.Conclusions:Our study shows that satellite tags can shed considerable light on migration strategies by revealing the use of different regions during the annual cycle and by providing detailed quantitative data on population connectivity and migration timing.展开更多
Genetic algorithm (GA) is one of the alternative approaches for solving the shortest path routing problem. In previous work, we have developed a coarse-grained parallel GA-based shortest path routing algorithm. With p...Genetic algorithm (GA) is one of the alternative approaches for solving the shortest path routing problem. In previous work, we have developed a coarse-grained parallel GA-based shortest path routing algorithm. With parallel GA, there is a GA operator called migration, where a chromosome is taken from one sub-population to replace a chromosome in another sub-population. Which chromosome to be taken and replaced is subjected to the migration strategy used. There are four different migration strategies that can be employed: best replace worst, best replace random, random replace worst, and random replace random. In this paper, we are going to evaluate the effect of different migration strategies on the parallel GA-based routing algorithm that has been developed in the previous work. Theoretically, the migration strategy best replace worst should perform better than the other strategies. However, result from simulation shows that even though the migration strategy best replace worst performs better most of the time, there are situations when one of the other strategies can perform just as well, or sometimes better.展开更多
BACKGROUND Multilevel artificial cervical disc replacement and anterior hybrid surgery have been introduced as reliable treatments for multilevel cervical degenerative disc disease.Surgical techniques are important fo...BACKGROUND Multilevel artificial cervical disc replacement and anterior hybrid surgery have been introduced as reliable treatments for multilevel cervical degenerative disc disease.Surgical techniques are important for resolving patients’symptoms and maintaining the normal functioning of cervical implants.However,the use of inappropriate surgical strategies could lead to complications such as implant migration and neurological deficit.In this paper,we summarize our surgical strategies used in multilevel cervical disc replacement and hybrid surgery into five major notes.CASE SUMMARY We share the key notes and our surgical procedures in the form of four typical case presentations.All patients were diagnosed with cervical degenerative disc disease with myelopathy or radiculopathy and needed multilevel cervical spine surgery.The first case demonstrated that index levels indicating the presence of highly serious spinal cord compression required a prioritized decompression.The second case demonstrated that the disc replacement should be performed before fusion in cervical hybrid surgery.The third and forth cases demonstrated that a top-down implantation sequence was needed in continuous two-level cervical disc replacement.The symptoms of all patients were significantly relieved after surgery.CONCLUSION We hope that our surgical strategies can help improve the performance and outcomes of multilevel cervical spine surgery.展开更多
In the process of transition from one social order to another, immigrants implement intentional or circumstantial adjustment strategies to position themselves in the new social structure, Within the broad perspective ...In the process of transition from one social order to another, immigrants implement intentional or circumstantial adjustment strategies to position themselves in the new social structure, Within the broad perspective of immigrants＇ incorporation into the receiving society, the present paper focuses on analysis at the micro-level, i,e., bottom-up strategies. These coping strategies define the social positioning of an individual. Through the structure-agency theoretical framework, this article analyses adjustment strategies used by immigrants in order to become members of the receiving society. This is discovered through semi-structured biographical interviews with female immigrants to Germany from former Soviet countries conducted by the author in 2012-2013 in Kaiserslautern. Several positioning strategies emerged in the course of these interviews： ＂destination as a way to a better life＂; ＂trip to joint self＂ which includes ＂identity as a task＂ and change of the behavioral patterns; shift in gender roles; usage of the imported educational capital; work of a ＂stranger next door＂; and social networking, The analysis of immigrants＇ adjustment strategies allows one to see the complexity of the incorporation processes into the receiving society： from essential personality traits such as imagination and aspirations, identity and roles to practically applicable aspects such as education, work, and networking.展开更多
Recently-developed capabilities for tracking the movements of individual birds over the course of a year or longer has provided increasing evidence for consistent individual differences in migration schedules and dest...Recently-developed capabilities for tracking the movements of individual birds over the course of a year or longer has provided increasing evidence for consistent individual differences in migration schedules and destinations. This raises questions about the relative importance of individual consistency versus flexibility in the evolution of migration strategies, and has implications for the ability of populations to respond to climatic change. Using geolocators, we tracked the migrations of Scopoli＇s shearwaters Calonectris diomedea breeding in Linosa （Italy） across three years, and analysed timing and spatial aspects of their movements. Birds showed remarkable variation in their main wintering destination along the western coast of Africa. We found significant individual consistency in the total distance traveled, time spent in transit, and time that individuals spent in the win- tering areas. We found extensive sex differences in scheduling, duration, distances and destinations of migratory journeys. We also found sex differences in the degree of individual consistency in aspects of migration behaviour. Despite strong evidence for individual consistency, which indicates that migration journeys from the same bird tended to be more similar than those of dif- ferent birds, there remained substantial intra-individual variation between years. Indeed, we also found clear annual differences in departure dates, return dates, wintering period, the total distance traveled and re^rn routes from wintering grounds back to the colony. These findings show that this population flexibly shifts migration schedules as well as routes between years in response to direct or indirect effects of heterogeneity in the environment, while maintaining consistent individual migration strategies [Current Zoology 60 （5）： 631-641, 2014].展开更多
With the advancement in the science and technology,cloud computing has become a recent trend in environment with immense requirement of infrastructure and resources.Load balancing of cloud computing environments is an...With the advancement in the science and technology,cloud computing has become a recent trend in environment with immense requirement of infrastructure and resources.Load balancing of cloud computing environments is an important matter of concern.The migration of the overloaded virtual machines(VMs)to the underloaded VM with optimized resource utilization is the effective way of the load balancing.In this paper,a new VM migration algorithm for the load balancing in the cloud is proposed.The migration algorithm proposed(EGSA-VMM)is based on exponential gravitational search algorithm which is the integration of gravitational search algorithm and exponential weighted moving average theory.In our approach,the migration is done based on the migration cost and QoS.The experimentation of proposed EGSA-based VM migration algorithm is compared with ACO and GSA.The simulation of experiments shows that the proposed EGSA-VMM algorithm achieves load balancing and reasonable resource utilization,which outperforms existing migration strategies in terms of number of VM migrations and number of SLA violations.展开更多
基金the National Institute of Bio-logical Resources,funded by the Ministry of Environment,Republic of Korea(grant numbers NIBR202216101 and NIBR202223101).
文摘Long-distance migratory birds travel more rapidly in spring than in autumn,as they face temporal breeding constraints.However,several species travel slower in spring owing to environmental influences,such as food availability and wind conditions.GPS trackers were attached to 17 Whooper Swans(Cygnus cygnus) inhabiting northeastern Mongolia,to determine their migration routes and stopover sites in spring and autumn.Differences between spring and autumn migrations,migration-influencing parameters,and the effect of spring stopover site temperatures were analyzed.Six swans completed perfect tours between their wintering and breeding sites,and these data were used for analysis.Spring migration lasted 57 days,with 49.2 days spent at 3.7 stopover sites.Autumn migration lasted 21.5 days,with 17.5 days spent at 1.0 stopover sites.Thus,the swans traveled more rapidly in autumn than in spring.Migration distance,number of stopovers,migration speed,and straightness were important migration determinants in both spring and autumn.Migration distance,stopover duration,number of stopovers,daily travel speed,travel duration,and migration speed differed significantly between spring and autumn.During spring migration,the temperature at the current stopover sites and that at the future stopover sites displayed significant variations(t=1585.8,df=631.6,p <0.001).These findings are critical for the conservation and management of Whooper Swans and their key habitats in East Asian regions,and the data are anticipated to make a particularly significant contribution toward developing detailed management plans for the conservation of their key habitats.
基金supported by the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2021QNLM020001)the Major Scientific and Technological Projects of Shandong Energy Group(No.SNKJ2022A06-R23)the Major Scientific and Technological Projects of CNPC(No.ZD2019-183-003).
文摘Intrinsic attenuation of the earth causes energy loss and phase distortion in seismic wave propagation.To obtain high-resolution imaging results,these negative effects must be considered during reverse time migration(RTM).We can easily implement attenuation-compensated RTM using the constant Q viscoacoustic wave equation with decoupled amplitude attenuation and phase dispersion terms.However,the nonphysical amplitude-compensation process will inevitably amplify the high-frequency noise in the wavefield in an exponential form,causing the numerical simulation to become unstable.This is due to the fact that the amplitude of the compensation grows exponentially with frequency.In order to achieve stable attenuation-compensated RTM,we modify the analytic expression of the attenuation compensation extrapolation operator and make it only compensate for amplitude loss within the effective frequency band.Based on this modified analytic formula,we then derive an explicit time-space domain attenuation compensation extrapolation operator.Finally,the implementation procedure of stable attenuation-compensated RTM is presented.In addition to being simple to implement,the newly proposed attenuation-compensated extrapolation operator is superior to the conventional low-pass filter in suppressing random noise,which will further improve the imaging resolution.We use two synthetic and one land seismic datasets to verify the stability and effectiveness of the proposed attenuationcompensated RTM in improving imaging resolution in viscous media.
基金funded by the Federal Agency for Nature Conservation under the Federal Ministry for the Environment,Nature Conservation and Nuclear Safety(FKZ 3510 860 1000)the Niedersachsische Wattenmeerstiftung(project 18/10)
文摘Background:While the general migration routes of most waders are known,details concerning connectivity between breeding grounds, stopover sites and wintering grounds are often lacking.Such information is critical from the conservation perspective and necessary for understanding the annual cycle.Studies are especially needed to identify key stopover sites in remote regions. Using satellite transmitters, we traced spring and autumn migration routes and connectivity of Grey Plovers on the East Atlantic Flyway.Our findings also revealed the timing,flight speed, and duration of migrations. Methods:We used ARGOS satellite transmitters to track migration routes of 11 Grey Plovers that were captured at the German Wadden Sea where they had stopped during migration.Birds were monitored for up to 3 years,2011-2014.Results:Monitoring signals indicated breeding grounds in the Taimyr and Yamal regions;important staging sites on the coasts of the southern Pechora Sea and the Kara Sea;and wintering areas that ranged from NW-Ireland to Guinea Bissau.The average distance traveled from wintering grounds to breeding grounds was 5534 km. Migration duration varied between 42 and 152 days;during this period birds spent about 95% of the time at staging sites.In spring most plovers crossed inland Eastern Europe, whereas in autumn most followed the coastline.Almost all of the birds departed during favorable wind conditions within just 4 days (27-30 May) on northward migration from the Wadden Sea.In spring birds migrated significantly faster between the Wadden Sea and the Arctic than on return migration in autumn (12 vs.37 days),with shorter stopovers during the northward passage.Conclusions:Our study shows that satellite tags can shed considerable light on migration strategies by revealing the use of different regions during the annual cycle and by providing detailed quantitative data on population connectivity and migration timing.
文摘Genetic algorithm (GA) is one of the alternative approaches for solving the shortest path routing problem. In previous work, we have developed a coarse-grained parallel GA-based shortest path routing algorithm. With parallel GA, there is a GA operator called migration, where a chromosome is taken from one sub-population to replace a chromosome in another sub-population. Which chromosome to be taken and replaced is subjected to the migration strategy used. There are four different migration strategies that can be employed: best replace worst, best replace random, random replace worst, and random replace random. In this paper, we are going to evaluate the effect of different migration strategies on the parallel GA-based routing algorithm that has been developed in the previous work. Theoretically, the migration strategy best replace worst should perform better than the other strategies. However, result from simulation shows that even though the migration strategy best replace worst performs better most of the time, there are situations when one of the other strategies can perform just as well, or sometimes better.
文摘BACKGROUND Multilevel artificial cervical disc replacement and anterior hybrid surgery have been introduced as reliable treatments for multilevel cervical degenerative disc disease.Surgical techniques are important for resolving patients’symptoms and maintaining the normal functioning of cervical implants.However,the use of inappropriate surgical strategies could lead to complications such as implant migration and neurological deficit.In this paper,we summarize our surgical strategies used in multilevel cervical disc replacement and hybrid surgery into five major notes.CASE SUMMARY We share the key notes and our surgical procedures in the form of four typical case presentations.All patients were diagnosed with cervical degenerative disc disease with myelopathy or radiculopathy and needed multilevel cervical spine surgery.The first case demonstrated that index levels indicating the presence of highly serious spinal cord compression required a prioritized decompression.The second case demonstrated that the disc replacement should be performed before fusion in cervical hybrid surgery.The third and forth cases demonstrated that a top-down implantation sequence was needed in continuous two-level cervical disc replacement.The symptoms of all patients were significantly relieved after surgery.CONCLUSION We hope that our surgical strategies can help improve the performance and outcomes of multilevel cervical spine surgery.
文摘In the process of transition from one social order to another, immigrants implement intentional or circumstantial adjustment strategies to position themselves in the new social structure, Within the broad perspective of immigrants＇ incorporation into the receiving society, the present paper focuses on analysis at the micro-level, i,e., bottom-up strategies. These coping strategies define the social positioning of an individual. Through the structure-agency theoretical framework, this article analyses adjustment strategies used by immigrants in order to become members of the receiving society. This is discovered through semi-structured biographical interviews with female immigrants to Germany from former Soviet countries conducted by the author in 2012-2013 in Kaiserslautern. Several positioning strategies emerged in the course of these interviews： ＂destination as a way to a better life＂; ＂trip to joint self＂ which includes ＂identity as a task＂ and change of the behavioral patterns; shift in gender roles; usage of the imported educational capital; work of a ＂stranger next door＂; and social networking, The analysis of immigrants＇ adjustment strategies allows one to see the complexity of the incorporation processes into the receiving society： from essential personality traits such as imagination and aspirations, identity and roles to practically applicable aspects such as education, work, and networking.
文摘Recently-developed capabilities for tracking the movements of individual birds over the course of a year or longer has provided increasing evidence for consistent individual differences in migration schedules and destinations. This raises questions about the relative importance of individual consistency versus flexibility in the evolution of migration strategies, and has implications for the ability of populations to respond to climatic change. Using geolocators, we tracked the migrations of Scopoli＇s shearwaters Calonectris diomedea breeding in Linosa （Italy） across three years, and analysed timing and spatial aspects of their movements. Birds showed remarkable variation in their main wintering destination along the western coast of Africa. We found significant individual consistency in the total distance traveled, time spent in transit, and time that individuals spent in the win- tering areas. We found extensive sex differences in scheduling, duration, distances and destinations of migratory journeys. We also found sex differences in the degree of individual consistency in aspects of migration behaviour. Despite strong evidence for individual consistency, which indicates that migration journeys from the same bird tended to be more similar than those of dif- ferent birds, there remained substantial intra-individual variation between years. Indeed, we also found clear annual differences in departure dates, return dates, wintering period, the total distance traveled and re^rn routes from wintering grounds back to the colony. These findings show that this population flexibly shifts migration schedules as well as routes between years in response to direct or indirect effects of heterogeneity in the environment, while maintaining consistent individual migration strategies [Current Zoology 60 （5）： 631-641, 2014].
文摘With the advancement in the science and technology,cloud computing has become a recent trend in environment with immense requirement of infrastructure and resources.Load balancing of cloud computing environments is an important matter of concern.The migration of the overloaded virtual machines(VMs)to the underloaded VM with optimized resource utilization is the effective way of the load balancing.In this paper,a new VM migration algorithm for the load balancing in the cloud is proposed.The migration algorithm proposed(EGSA-VMM)is based on exponential gravitational search algorithm which is the integration of gravitational search algorithm and exponential weighted moving average theory.In our approach,the migration is done based on the migration cost and QoS.The experimentation of proposed EGSA-based VM migration algorithm is compared with ACO and GSA.The simulation of experiments shows that the proposed EGSA-VMM algorithm achieves load balancing and reasonable resource utilization,which outperforms existing migration strategies in terms of number of VM migrations and number of SLA violations.
