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
The movement of Cu in a HfO2-based resistive random access memory （RRAM） device is investigated in depth by first-principle calculations. Thermodynamics analysis shows that the dominant motion of Cu tends to be alon...The movement of Cu in a HfO2-based resistive random access memory （RRAM） device is investigated in depth by first-principle calculations. Thermodynamics analysis shows that the dominant motion of Cu tends to be along the [001] orientation with a faster speed. The migration barriers along different routes are compared and reveal that the [001] orientation is the optimal migration route of Cu in HfO2, which is more favorable for Cu transportation. Furthermore, the preferable HfOz growth orientation along [100], corresponding to Cu migration along [001], is also observed. Therefore, it is proposed that the HfO2 material should grow along [100] and the operating voltage should be applied along [001], which will contribute to the improvement of the response speed and the reduction of power consumption of RRAM.展开更多
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.
基金supported by the National Natural Science Foundation of China(No.61376106)
文摘The movement of Cu in a HfO2-based resistive random access memory （RRAM） device is investigated in depth by first-principle calculations. Thermodynamics analysis shows that the dominant motion of Cu tends to be along the [001] orientation with a faster speed. The migration barriers along different routes are compared and reveal that the [001] orientation is the optimal migration route of Cu in HfO2, which is more favorable for Cu transportation. Furthermore, the preferable HfOz growth orientation along [100], corresponding to Cu migration along [001], is also observed. Therefore, it is proposed that the HfO2 material should grow along [100] and the operating voltage should be applied along [001], which will contribute to the improvement of the response speed and the reduction of power consumption of RRAM.
