7 research outputs found
Superconductivity in Co-doped LaFeAsO
Here we report the synthesis and basic characterization of LaFe1-xCoxAsO for
several values of x. The parent phase LaFeAsO orders antiferromagnetically (TN
~ 145 K). Replacing Fe with Co is expected to both electron dope the system and
introduce disorder in the FeAs layer. For x = 0.05 antiferromagnetic order is
destroyed and superconductivity is observed at Tconset = 11.2 K. For x = 0.11
superconductivity is observed at Tc(onset) = 14.3 K, and for x = 0.15 Tc = 6.0
K. Superconductivity is not observed for x = 0.2 and 0.5, but for x = 1, the
material appears to be ferromagnetic (Tc ~ 56 K) as judged by magnetization
measurements. We conclude that Co is an effective dopant to induce
superconductivity. Somewhat surprisingly, the system appears to tolerate
considerable disorder in the FeAs planes.Comment: 19 pages, 9 figure
How many bird and mammal extinctions has recent conservation action prevented?
Aichi Target 12 of the Convention on Biological Diversity (CBD) aims to âprevent extinctions of known threatened speciesâ. To measure its success, we used a Delphi expert elicitation method to estimate the number of bird and mammal species whose extinctions were prevented by conservation action in 1993 - 2020 (the lifetime of the CBD) and 2010 - 2020 (the timing of Aichi Target 12). We found that conservation prevented 21â32 bird and 7â16 mammal extinctions since 1993, and 9â18 bird and 2â7 mammal extinctions since 2010. Many remain highly threatened, and may still become extinct in the near future. Nonetheless, given that ten bird and five mammal species did go extinct (or are strongly suspected to) since 1993, extinction rates would have been 2.9â4.2 times greater without conservation action. While policy commitments have fostered significant conservation achievements, future biodiversity action needs to be scaled up to avert additional extinctions
How many bird and mammal extinctions has recent conservation action prevented?
Aichi Target 12 of the Convention on Biological Diversity (CBD) contains the
aim to âprevent extinctions of known threatened speciesâ. To measure the degree
to which this was achieved, we used expert elicitation to estimate the number
of bird and mammal species whose extinctions were prevented by conservation
action in 1993â2020 (the lifetime of the CBD) and 2010â2020 (the timing of Aichi
Target 12). We found that conservation action prevented 21â32 bird and 7â16
mammal extinctions since 1993, and 9â18 bird and two to seven mammal extinctions
since 2010. Many remain highly threatened and may still become extinct.
Considering that 10 bird and five mammal species did go extinct (or are strongly
suspected to) since 1993, extinction rates would have been 2.9â4.2 times greater
without conservation action. While policy commitments have fostered significant
conservation achievements, future biodiversity action needs to be scaled up
to avert additional extinctions.https://wileyonlinelibrary.com/journal/conlMammal Research Institut