With the Gravity Recovery and Climate Experiment {GRACE) mission as the prime example, an overview is given on the management and processing of Level IA data of a low-low satellite to satellite tracking mission. To i...With the Gravity Recovery and Climate Experiment {GRACE) mission as the prime example, an overview is given on the management and processing of Level IA data of a low-low satellite to satellite tracking mission. To illustrate the underlying principle and algorithm, a detailed study is made on the K-band ranging (KBR) assembly, which includes the measurement principles, modeling of noises, the generation of Level 1A data from that of Level 0 as well as Level IA to Level IB data processing.展开更多
During the period August 17-28, 2001, in collaboration with the Provincial Bureau of Oceanography & Fisheries of Guangdong and the South China Institute for Endangered Species, the South China Sea Institute of Oce...During the period August 17-28, 2001, in collaboration with the Provincial Bureau of Oceanography & Fisheries of Guangdong and the South China Institute for Endangered Species, the South China Sea Institute of Oceanology, a CAS affiliate in the city of Guangzhou, conducted a sea turtle satellite tracking project at Haigui Bay (Fig. 1) in the vicinity of Gangkou Town, Huidong County, Guangdong Province.展开更多
BeiDou-3 navigation satellite system was officially opened in 2020.While bringing high-performance services to people around the world,the navigation system requires well-designed BeiDou antennas.In this paper,we prop...BeiDou-3 navigation satellite system was officially opened in 2020.While bringing high-performance services to people around the world,the navigation system requires well-designed BeiDou antennas.In this paper,we propose a wideband circularly polarized high-performance BeiDou antenna.The antenna realizes wideband circularly polarized radiation through a four-port sequential feed network,and the phase imbalance of the feed network from 1.05 to 1.80 GHz is less than 7°.The manufactured antenna demonstrates a return loss of more than 13 dB and an axial ratio<3 dB over the entire global navigation satellite system(GNSS)frequency band.The right-handed circular polarization(RHCP)gain of the proposed antenna is greater than 4 dB in the GNSS low-frequency band and can reach more than 7.1 dB in the high-frequency band.Dimension of the proposed antenna is 120 mm×120 mm×20 mm,i.e.,0.54λo×0.54λo×0.09λo,whereλo is the wavelength of the center frequency.The proposed antenna connected to a GNSS receiver has tracked 12 BeiDou satellites with C/N0 ratios of GNSS signals greater than 30 dB.Such a high-performance antenna provides a basis for high-quality positioning services.展开更多
Geovisual analytics provides a framework for the development of decision support tools for landscape design,analysis and optimisation.An important application is modelling the spatial-temporal movements of ruminants a...Geovisual analytics provides a framework for the development of decision support tools for landscape design,analysis and optimisation.An important application is modelling the spatial-temporal movements of ruminants and their grazing behaviour using global positioning system(GPS)collar units.This study describes the mapping and analysis of spatial distributions of animal waste products(which correlate with farm nitrogen[N]emissions)and also determination of animal feeding preferences(which correlate with animal welfare and production).Segmentation of local regions of animal N emissions provides support in meeting targets for local and international N leaching and greenhouse gas emissions.An agent-based model was used for prescreening in order to gain insights into the clustering behaviour of sheep during feeding activities.Subsequent spatial analysis demonstrated that livestock excreta are not always randomly located,but concentrated around highly localised animal gathering points,separated by the nature of the excretion.In a separate study,the statistical significance of feeding choices was determined by testing a null hypothesis on animal boundary transitions between adjacent pastures using the binomial approximation.The analysis also included compensation for the precision of the GPS sensor,which produced a fuzzy decision boundary.展开更多
With the loss of substantial natural wetlands in coastal zones,artificial wetlands provide alternative habitats for many shorebirds.Scientific management of artificial wetlands used by shorebirds plays an important ro...With the loss of substantial natural wetlands in coastal zones,artificial wetlands provide alternative habitats for many shorebirds.Scientific management of artificial wetlands used by shorebirds plays an important role in maintaining the stability of shorebird population.Satellite tracking technique can obtain high-precision location information of individuals day and night,providing a good technical support for the study of quantitative relationship between waterfowls and their habitats.In this study,satellite tracking method,Remote Sensing(RS)and Geographic Information System(GIS)technology were used to analyze the activity pattern and habitat utilization characteristics of Pied Avocet during breeding period in an artificial wetland complex in the Yellow River Delta(YRD),China.The results showed that the breeding Pied Avocets had a small range of activity,with a total core and main home range of 33.10 km^(2) and 216.30 km^(2),respectively.This species tended to forage in the pond and salt pan during the day and night,respectively,with an unfixed staying time in the breeding ground.The distance between breeding ground and feeding ground was less than 6 km.It is emphasized that in addition to improving the conditions of the remaining natural habitats,effective managing artificial habitats is a priority for shorebird conservation.This research could provide reference for the management of artificial wetlands in coastal zones and supply technique support for the protection of shorebirds and their habitats,and alleviate human-bird conflicts and sustainable development of coastal zones.展开更多
The satellite constellation classes, which are suitable for the medium earth orbit tracking and data relay satellite system (MEO-TDRSS) of China, are investigated. On the basis of the functionality and the traffic d...The satellite constellation classes, which are suitable for the medium earth orbit tracking and data relay satellite system (MEO-TDRSS) of China, are investigated. On the basis of the functionality and the traffic distribution characteristic of MEO-TDRSS, the coverage performance and inter-satellite link properties of four different constellation schemes are compared by simulations. Simulation results indicate that the rosette and common-track constellations, whose satellites are distributed on the celestial sphere more uniformly, are appropriate for the implementation of MEO-TDRSS of China.展开更多
The relationship between habitat and behaviour provides important information for species management.For large,free roaming,marine animals satellite tags provide high resolution information on movement,but such datase...The relationship between habitat and behaviour provides important information for species management.For large,free roaming,marine animals satellite tags provide high resolution information on movement,but such datasets are restricted due to cost.Extracting additional biologically important information from these data would increase utilisation and value.Several modelling approaches have been developed to identify behavioural states in tracking data.The objective of this study was to evaluate a behavioural state prediction model for blue shark(Prionace glauca)ARGOS surface location-only data.The novel nature of the six SPLASH satellite tags used enabled behavioural events to be identified in blue shark dive data and accurately mapped spatio-temporally along respective surface location-only tracks.Behavioural states modelled along the six surface location-only tracks were then tested against observed behavioural events to evaluate the model’s accuracy.Results showed that the Behavioural Change Point Analysis(BCPA)model augmented with K means clustering analysis performed well for predicting foraging behaviour(correct 86%of the time).Prediction accuracy was lower for searching(52%)and travelling(63%)behaviour,likely related to the numerical dominance of foraging events in dive data.The model’s validation for predicting foraging behaviour justified its application to nine additional surface location-only(SPOT tag)tracks,substantially increasing the utilisation of expensive and rare data.Results enabled the critical behavioural state of foraging,to be mapped throughout the entire home range of blue sharks,allowing drivers of critical habitat to be investigated.This validation strengthens the use of such modelling to interpret historic and future datasets,for blue sharks but also other species,contributing to conservational management.展开更多
While adopting an elevation-over-azimuth architecture by an inter-satellite linkage antenna of a user satellite, a zenith pass problem always occurs when the antenna is tracing the tracking and data relay satellite (...While adopting an elevation-over-azimuth architecture by an inter-satellite linkage antenna of a user satellite, a zenith pass problem always occurs when the antenna is tracing the tracking and data relay satellite (TDRS). This paper deals with this problem by way of, firstly, introducing movement laws of the inter-satellite linkage to predict the movement of the user satellite antenna followed by analyzing the potential pass moment and the actual one of the zenith pass in detail. A number of specific orbit altitudes for the user satellite that can remove the blindness zone are obtained. Finally, on the base of the predicted results from the movement laws of the inter-satellite linkage, the zenith pass tracing strategies for the user satellite antenna are designed under the program guidance using a trajectory preprocessor. Simulations have confirmed the reasonability and feasibility of the strategies in dealing with the zenith pass problem.展开更多
The Chinese Egret(Egretta eulophotes)is a globally threatened bird species living on the coast and islands of Liaoning,northeastern China,mainly in summer.To further protect the breeding population of Chinese Egrets,i...The Chinese Egret(Egretta eulophotes)is a globally threatened bird species living on the coast and islands of Liaoning,northeastern China,mainly in summer.To further protect the breeding population of Chinese Egrets,it is important to understand the current protection status of their distribution sites at pre-migration period and migration routes.Thirty-three individuals were tagged with satellite transmitters at Fantuo Island in Changhai and Xingren Island in Zhuanghe,Liaoning Province,northeastern China,in July of 2016,2017,and 2018,to identify important distribution sites during the pre-migration period,as well as detailed migration routes.The results showed that coastal mudflats in Liaoning and the west coast of North Korea were important feeding and roosting sites for fledgling Chinese Egrets from August to September.The home range sizes in August were significantly larger than in September.The eastern coast from Shandong to Guangdong,as well as Taiwan,China,and Manila Bay and Galileo Islands in the Philippines,were important stopover sites during fall migration.Specifically,we found that the egrets’autumn migration could be divided into four routes,i.e.,sea-crossing migration(SCM),coastal migration(CM),inland migration(IM),and mixed migration(MM).The migration distance,timing,speed,and straightness of the four routes also differed.The SCM routes were the straightest,and had the fastest migration speed and shortest travel time,while the IM routes had the lowest straightness and speed,and the longest duration.Manila Bay and Bohol Island in the Philippines,the west coast of Tanintharyi in Myanmar,and the Zengwun River Estuary in Taiwan,China,were wintering sites.Our findings on the key distribution sites along pre-migration and fall migration routes,including some stopover sites,have important implications for the conservation of and global action plan development for the vulnerable Chinese Egret.展开更多
Determining the migration routes and connections of migratory birds at the population level helps clarify intraspecific differences in migration.Five subspecies have been recognized in the Whimbrel(Numenius phaeopus)i...Determining the migration routes and connections of migratory birds at the population level helps clarify intraspecific differences in migration.Five subspecies have been recognized in the Whimbrel(Numenius phaeopus)in Eurasia.Ssp.rogachevae is the most recently described subspecies.It breeds in Central Siberia,while its non-breeding region and migration routes are still unclear.We tracked the migration of Eurasian Whimbrels captured at three non-breeding sites(Moreton Bay in east coast of Australia,Roebuck Bay in Northwest Australia and Sungei Buloh Wetland in Singapore)and two migration stopover sites(Chongming Dongtan and Mai Po Wetland in China).We determined the breeding sites and inferred the subspecies of the tagged birds in the East Asian–Australasian Flyway(EAAF)based on the known breeding distribution of each subspecies.Of the 30 tagged birds,6 and 21 birds bred in the breeding range of ssp.rogachevae and variegatus,respectively;one bred in the presumed transition area between the breeding range of ssp.phaeopus and rogachevae,and two bred in the region between the breeding range of ssp.rogachevae and variegatus.The birds that bred in the ssp.rogachevae breeding range spent their non-breeding season in the northern Sumatra,Singapore,East Java and Northwest Australia and mainly stopped over along China's coasts during migration.None of our birds bred in the exclusive breeding range of the phaeopus subspecies.Previous studies have predicted that rogachevae whimbrels migrate along the Central Asian Flyway and spend the non-breeding season in West India and East Africa.We found that at least some rogachevae whimbrels migrate along the EAAF and spend the non-breeding season in Southeast Asia and Australia.The ssp.phaeopus is at best sparsely distributed in the EAAF in the west region,or possibly does not occur at all.展开更多
This paper focuses on the type synthesis of two degree-of-freedom(2-DoF) rotational parallel mechanisms(RPMs) that would be applied as mechanisms actuating the inter-satellite link antenna. Based upon Lie group theory...This paper focuses on the type synthesis of two degree-of-freedom(2-DoF) rotational parallel mechanisms(RPMs) that would be applied as mechanisms actuating the inter-satellite link antenna. Based upon Lie group theory, two steps are necessary to synthesize 2-DoF RPMs except describing the continuous desired motions of the moving platform. They are respectively generation of required open-loop limbs between the fixed base and the moving platform and definition of assembly principles for these limbs. Firstly, all available displacement subgroups or submanifolds are obtained readily according to that the continuous motion of the moving platform is the intersection of those of all open-loop limbs. These subgroups or submanifolds are used to generate all the topology structures of limbs. By describing the characteristics of the displacement subgroups and submanifolds intuitively through employing simple geometrical symbols, their intersection and union operations can be carried out easily. Based on this, the assembly principles of two types are defined to synthesize all 2-DoF RPMs using obtained limbs. Finally, two novel categories of 2-DoF RPMs are provided by introducing a circular track and an articulated rotating platform,respectively. This work can lay the foundations for analysis and optimal design of 2-DoF RPMs that actuate the inter-satellite link antenna.展开更多
Tens of thousands of demoiselle cranes’crossing the Himalayas to the Indian subcontinent have been reported for decades,but their exact spring migration route remained a mystery until our previous study found they ma...Tens of thousands of demoiselle cranes’crossing the Himalayas to the Indian subcontinent have been reported for decades,but their exact spring migration route remained a mystery until our previous study found they made a detour in spring along the western edge of the Himalayas and crossed the Mongolian Plateau to their breeding areas based on satellite telemetry of 3 birds.To corroborate the loop migration pattern and explore whether demoiselle crane’s loop migration route is shaped by time-and energy-minimization strategies in spring and autumn and how the temporal and spatial variation of environmental conditions contribute to crane’s selection of migration routes,we tracked 11 satellite-tagged demoiselle cranes from their breeding area in China and Russia,simulated 2 pseudo migration routes,and then compared the environmental conditions,time,and energy cost between true and pseudo routes in the same season.Results show that demoiselles’spring migration obeyed time-minimization hypothesis,avoiding the colder Qinghai-Tibet Plateau,benefited by abundant food and higher thermal and orographic uplift along the route;autumn migration follows energy-minimization hypothesis with the shorter route.Our research will contribute to uncover the mechanical reasons why demoiselle crane avoids crossing the giant barrier of the Himalayas in spring,and shapes a loop migration route.展开更多
Dispersal is an important life history trait that plays a crucial role in avoiding inbreeding.Uncovering the dispersal pattern of a threatened species facilitates conservation efforts.Most species of Galliformes are f...Dispersal is an important life history trait that plays a crucial role in avoiding inbreeding.Uncovering the dispersal pattern of a threatened species facilitates conservation efforts.Most species of Galliformes are forest-dwelling terrestrial birds with a weak dispersal ability and high conservation priorities.However,little is known about the dispersal behavior and dispersal pattern of Galliformes species such as Reeves's pheasant Syrmaticus reevesi,a globally vulnerable species endemic to China.Here,we integrated behavioral and genetic analyses to inves-tigate the dispersal pattern of Reeves's pheasant.Our results revealed that both females and males would disperse,although the overall dispersal pattern was more likely to be male-biased.Reeves's pheasant population had a low level of genetic diversity and a mild level of inbreeding.Speculation low genetic diversity was resulted from fragmented habitat,and male-biased dispersal may reduce the opportunity of inbreeding.Our research indicated that sex-biased dispersal patterns may be a behavioral mechanism adopted by wildlife to avoid inbreeding inafragmented habitat.展开更多
基金the project entitled"Advanced Gravity Measurement in Space"supported by the National Space Science Center,Chinese Academy of Sciences Profs.Wenrui Hu and Houze Xu's effort to promote satellite gravity research in China motivated the feasibility study in the first placeSupport from National Natural Science Foundation of China(11305255,11171329 and 41404019)funding from State Key Laboratory of Geodesy and Earth's Dynamics,Institute of Geodesy and Geophysics,Chinese Academy of Sciences(SKLGED2013-3-8-E)are acknowledged
文摘With the Gravity Recovery and Climate Experiment {GRACE) mission as the prime example, an overview is given on the management and processing of Level IA data of a low-low satellite to satellite tracking mission. To illustrate the underlying principle and algorithm, a detailed study is made on the K-band ranging (KBR) assembly, which includes the measurement principles, modeling of noises, the generation of Level 1A data from that of Level 0 as well as Level IA to Level IB data processing.
基金The test is a research project supported by the CAS sponsored Knowl-edge Innovation Program and Guangdong Province s Bureau of Ocean-ography&Fisheries.Its participants also include Liu Yun,a graduate student at the South China Sea Institute of Oceanology,Chan Kinfung of the Hong Kong Agriculture,Fisheries&Conservation Department,and senior engineer Gu Hexiang of the Haigui Bay Nature Reserve.
文摘During the period August 17-28, 2001, in collaboration with the Provincial Bureau of Oceanography & Fisheries of Guangdong and the South China Institute for Endangered Species, the South China Sea Institute of Oceanology, a CAS affiliate in the city of Guangzhou, conducted a sea turtle satellite tracking project at Haigui Bay (Fig. 1) in the vicinity of Gangkou Town, Huidong County, Guangdong Province.
文摘BeiDou-3 navigation satellite system was officially opened in 2020.While bringing high-performance services to people around the world,the navigation system requires well-designed BeiDou antennas.In this paper,we propose a wideband circularly polarized high-performance BeiDou antenna.The antenna realizes wideband circularly polarized radiation through a four-port sequential feed network,and the phase imbalance of the feed network from 1.05 to 1.80 GHz is less than 7°.The manufactured antenna demonstrates a return loss of more than 13 dB and an axial ratio<3 dB over the entire global navigation satellite system(GNSS)frequency band.The right-handed circular polarization(RHCP)gain of the proposed antenna is greater than 4 dB in the GNSS low-frequency band and can reach more than 7.1 dB in the high-frequency band.Dimension of the proposed antenna is 120 mm×120 mm×20 mm,i.e.,0.54λo×0.54λo×0.09λo,whereλo is the wavelength of the center frequency.The proposed antenna connected to a GNSS receiver has tracked 12 BeiDou satellites with C/N0 ratios of GNSS signals greater than 30 dB.Such a high-performance antenna provides a basis for high-quality positioning services.
文摘Geovisual analytics provides a framework for the development of decision support tools for landscape design,analysis and optimisation.An important application is modelling the spatial-temporal movements of ruminants and their grazing behaviour using global positioning system(GPS)collar units.This study describes the mapping and analysis of spatial distributions of animal waste products(which correlate with farm nitrogen[N]emissions)and also determination of animal feeding preferences(which correlate with animal welfare and production).Segmentation of local regions of animal N emissions provides support in meeting targets for local and international N leaching and greenhouse gas emissions.An agent-based model was used for prescreening in order to gain insights into the clustering behaviour of sheep during feeding activities.Subsequent spatial analysis demonstrated that livestock excreta are not always randomly located,but concentrated around highly localised animal gathering points,separated by the nature of the excretion.In a separate study,the statistical significance of feeding choices was determined by testing a null hypothesis on animal boundary transitions between adjacent pastures using the binomial approximation.The analysis also included compensation for the precision of the GPS sensor,which produced a fuzzy decision boundary.
基金Under the auscpices of Shandong Provincial Natural Science Foundation (No.ZR2020QD090)Research Funds of Beijing VMinFull Limted (No.VMF2021RS)+1 种基金National Natural Science Foundation of China (No.42176221)Seed Project of Yantai Institute of Coastal Zone Research,Chinese Academy of Sciences (No.YICE351030601)。
文摘With the loss of substantial natural wetlands in coastal zones,artificial wetlands provide alternative habitats for many shorebirds.Scientific management of artificial wetlands used by shorebirds plays an important role in maintaining the stability of shorebird population.Satellite tracking technique can obtain high-precision location information of individuals day and night,providing a good technical support for the study of quantitative relationship between waterfowls and their habitats.In this study,satellite tracking method,Remote Sensing(RS)and Geographic Information System(GIS)technology were used to analyze the activity pattern and habitat utilization characteristics of Pied Avocet during breeding period in an artificial wetland complex in the Yellow River Delta(YRD),China.The results showed that the breeding Pied Avocets had a small range of activity,with a total core and main home range of 33.10 km^(2) and 216.30 km^(2),respectively.This species tended to forage in the pond and salt pan during the day and night,respectively,with an unfixed staying time in the breeding ground.The distance between breeding ground and feeding ground was less than 6 km.It is emphasized that in addition to improving the conditions of the remaining natural habitats,effective managing artificial habitats is a priority for shorebird conservation.This research could provide reference for the management of artificial wetlands in coastal zones and supply technique support for the protection of shorebirds and their habitats,and alleviate human-bird conflicts and sustainable development of coastal zones.
基金the National Natural Science Foundation of China (60372013)
文摘The satellite constellation classes, which are suitable for the medium earth orbit tracking and data relay satellite system (MEO-TDRSS) of China, are investigated. On the basis of the functionality and the traffic distribution characteristic of MEO-TDRSS, the coverage performance and inter-satellite link properties of four different constellation schemes are compared by simulations. Simulation results indicate that the rosette and common-track constellations, whose satellites are distributed on the celestial sphere more uniformly, are appropriate for the implementation of MEO-TDRSS of China.
文摘The relationship between habitat and behaviour provides important information for species management.For large,free roaming,marine animals satellite tags provide high resolution information on movement,but such datasets are restricted due to cost.Extracting additional biologically important information from these data would increase utilisation and value.Several modelling approaches have been developed to identify behavioural states in tracking data.The objective of this study was to evaluate a behavioural state prediction model for blue shark(Prionace glauca)ARGOS surface location-only data.The novel nature of the six SPLASH satellite tags used enabled behavioural events to be identified in blue shark dive data and accurately mapped spatio-temporally along respective surface location-only tracks.Behavioural states modelled along the six surface location-only tracks were then tested against observed behavioural events to evaluate the model’s accuracy.Results showed that the Behavioural Change Point Analysis(BCPA)model augmented with K means clustering analysis performed well for predicting foraging behaviour(correct 86%of the time).Prediction accuracy was lower for searching(52%)and travelling(63%)behaviour,likely related to the numerical dominance of foraging events in dive data.The model’s validation for predicting foraging behaviour justified its application to nine additional surface location-only(SPOT tag)tracks,substantially increasing the utilisation of expensive and rare data.Results enabled the critical behavioural state of foraging,to be mapped throughout the entire home range of blue sharks,allowing drivers of critical habitat to be investigated.This validation strengthens the use of such modelling to interpret historic and future datasets,for blue sharks but also other species,contributing to conservational management.
文摘While adopting an elevation-over-azimuth architecture by an inter-satellite linkage antenna of a user satellite, a zenith pass problem always occurs when the antenna is tracing the tracking and data relay satellite (TDRS). This paper deals with this problem by way of, firstly, introducing movement laws of the inter-satellite linkage to predict the movement of the user satellite antenna followed by analyzing the potential pass moment and the actual one of the zenith pass in detail. A number of specific orbit altitudes for the user satellite that can remove the blindness zone are obtained. Finally, on the base of the predicted results from the movement laws of the inter-satellite linkage, the zenith pass tracing strategies for the user satellite antenna are designed under the program guidance using a trajectory preprocessor. Simulations have confirmed the reasonability and feasibility of the strategies in dealing with the zenith pass problem.
基金supported by the National Key Research and Development Program of China (No. 2019YFA0607103)Program of National Forestry and Grassland Administration (No.213023721203)
文摘The Chinese Egret(Egretta eulophotes)is a globally threatened bird species living on the coast and islands of Liaoning,northeastern China,mainly in summer.To further protect the breeding population of Chinese Egrets,it is important to understand the current protection status of their distribution sites at pre-migration period and migration routes.Thirty-three individuals were tagged with satellite transmitters at Fantuo Island in Changhai and Xingren Island in Zhuanghe,Liaoning Province,northeastern China,in July of 2016,2017,and 2018,to identify important distribution sites during the pre-migration period,as well as detailed migration routes.The results showed that coastal mudflats in Liaoning and the west coast of North Korea were important feeding and roosting sites for fledgling Chinese Egrets from August to September.The home range sizes in August were significantly larger than in September.The eastern coast from Shandong to Guangdong,as well as Taiwan,China,and Manila Bay and Galileo Islands in the Philippines,were important stopover sites during fall migration.Specifically,we found that the egrets’autumn migration could be divided into four routes,i.e.,sea-crossing migration(SCM),coastal migration(CM),inland migration(IM),and mixed migration(MM).The migration distance,timing,speed,and straightness of the four routes also differed.The SCM routes were the straightest,and had the fastest migration speed and shortest travel time,while the IM routes had the lowest straightness and speed,and the longest duration.Manila Bay and Bohol Island in the Philippines,the west coast of Tanintharyi in Myanmar,and the Zengwun River Estuary in Taiwan,China,were wintering sites.Our findings on the key distribution sites along pre-migration and fall migration routes,including some stopover sites,have important implications for the conservation of and global action plan development for the vulnerable Chinese Egret.
基金financially supported by the National Natural Science Foundation of China (No. 31830089 and 31772467)Science and Technology Commission of Shanghai Municipality (21DZ1201902)+2 种基金World Wide Fund for Nature Beijing Office (10003881)Shanghai Landscaping and City Appearance Administrative Bureau (G201610)Scientific Research Fund of Yunnan Provincial Education Department (2022J0847)
文摘Determining the migration routes and connections of migratory birds at the population level helps clarify intraspecific differences in migration.Five subspecies have been recognized in the Whimbrel(Numenius phaeopus)in Eurasia.Ssp.rogachevae is the most recently described subspecies.It breeds in Central Siberia,while its non-breeding region and migration routes are still unclear.We tracked the migration of Eurasian Whimbrels captured at three non-breeding sites(Moreton Bay in east coast of Australia,Roebuck Bay in Northwest Australia and Sungei Buloh Wetland in Singapore)and two migration stopover sites(Chongming Dongtan and Mai Po Wetland in China).We determined the breeding sites and inferred the subspecies of the tagged birds in the East Asian–Australasian Flyway(EAAF)based on the known breeding distribution of each subspecies.Of the 30 tagged birds,6 and 21 birds bred in the breeding range of ssp.rogachevae and variegatus,respectively;one bred in the presumed transition area between the breeding range of ssp.phaeopus and rogachevae,and two bred in the region between the breeding range of ssp.rogachevae and variegatus.The birds that bred in the ssp.rogachevae breeding range spent their non-breeding season in the northern Sumatra,Singapore,East Java and Northwest Australia and mainly stopped over along China's coasts during migration.None of our birds bred in the exclusive breeding range of the phaeopus subspecies.Previous studies have predicted that rogachevae whimbrels migrate along the Central Asian Flyway and spend the non-breeding season in West India and East Africa.We found that at least some rogachevae whimbrels migrate along the EAAF and spend the non-breeding season in Southeast Asia and Australia.The ssp.phaeopus is at best sparsely distributed in the EAAF in the west region,or possibly does not occur at all.
基金supported by the National Natural Science Foundation of China (No. 51475321)Tianjin Research Program of Application Foundation and Advanced Technology (No. 15JCZDJC38900 and No. 16JCYBJC19300)
文摘This paper focuses on the type synthesis of two degree-of-freedom(2-DoF) rotational parallel mechanisms(RPMs) that would be applied as mechanisms actuating the inter-satellite link antenna. Based upon Lie group theory, two steps are necessary to synthesize 2-DoF RPMs except describing the continuous desired motions of the moving platform. They are respectively generation of required open-loop limbs between the fixed base and the moving platform and definition of assembly principles for these limbs. Firstly, all available displacement subgroups or submanifolds are obtained readily according to that the continuous motion of the moving platform is the intersection of those of all open-loop limbs. These subgroups or submanifolds are used to generate all the topology structures of limbs. By describing the characteristics of the displacement subgroups and submanifolds intuitively through employing simple geometrical symbols, their intersection and union operations can be carried out easily. Based on this, the assembly principles of two types are defined to synthesize all 2-DoF RPMs using obtained limbs. Finally, two novel categories of 2-DoF RPMs are provided by introducing a circular track and an articulated rotating platform,respectively. This work can lay the foundations for analysis and optimal design of 2-DoF RPMs that actuate the inter-satellite link antenna.
基金funding is from the National Natural Science Foundation of China awarded to Yumin Guo(grant no.31770573 and no.31570532)supported by Alliance of International Science Organization(ANSO)(Project ID:ANSO-CR-KP-2020-08)。
文摘Tens of thousands of demoiselle cranes’crossing the Himalayas to the Indian subcontinent have been reported for decades,but their exact spring migration route remained a mystery until our previous study found they made a detour in spring along the western edge of the Himalayas and crossed the Mongolian Plateau to their breeding areas based on satellite telemetry of 3 birds.To corroborate the loop migration pattern and explore whether demoiselle crane’s loop migration route is shaped by time-and energy-minimization strategies in spring and autumn and how the temporal and spatial variation of environmental conditions contribute to crane’s selection of migration routes,we tracked 11 satellite-tagged demoiselle cranes from their breeding area in China and Russia,simulated 2 pseudo migration routes,and then compared the environmental conditions,time,and energy cost between true and pseudo routes in the same season.Results show that demoiselles’spring migration obeyed time-minimization hypothesis,avoiding the colder Qinghai-Tibet Plateau,benefited by abundant food and higher thermal and orographic uplift along the route;autumn migration follows energy-minimization hypothesis with the shorter route.Our research will contribute to uncover the mechanical reasons why demoiselle crane avoids crossing the giant barrier of the Himalayas in spring,and shapes a loop migration route.
基金supported by the National Natural Science Foundation of China(grant 31872240)the Biodiversity Survey,Monitoring,and Assessment Project of the Ministry of Ecology and the Environment,China(grant 2019HB2096001006).
文摘Dispersal is an important life history trait that plays a crucial role in avoiding inbreeding.Uncovering the dispersal pattern of a threatened species facilitates conservation efforts.Most species of Galliformes are forest-dwelling terrestrial birds with a weak dispersal ability and high conservation priorities.However,little is known about the dispersal behavior and dispersal pattern of Galliformes species such as Reeves's pheasant Syrmaticus reevesi,a globally vulnerable species endemic to China.Here,we integrated behavioral and genetic analyses to inves-tigate the dispersal pattern of Reeves's pheasant.Our results revealed that both females and males would disperse,although the overall dispersal pattern was more likely to be male-biased.Reeves's pheasant population had a low level of genetic diversity and a mild level of inbreeding.Speculation low genetic diversity was resulted from fragmented habitat,and male-biased dispersal may reduce the opportunity of inbreeding.Our research indicated that sex-biased dispersal patterns may be a behavioral mechanism adopted by wildlife to avoid inbreeding inafragmented habitat.