Numbers

685,736 tourists visited Kenya in the first eight months of 2018

Time and energy minimization strategy codetermine the loop migration of demoiselle cranes around the Himalayas

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.

Fusion reactions around the barrier for Be+^(238)U

Fusion-evaporation cross sections of^(238)U(^(9)Be,5n)^(242)Cm are measured over a wide energy range around the Coulomb barrier.These measured cross sections are compared with model calculations using two codes,namely HIVAP2 and KE WPIE2.HIVAP2 calculations overestimate the measured fusion-evaporation cross sections by a factor of approximately 3.In KEWPIE2 calculations,two approaches,namely the Wentzel-Kramers-Brillouin(WKB)approximation and the empirical barrier-distribution(EBD)method,are used for the capture probability;both of them properly describe the measured cross sections.Additionally,fusion cross sections of^(7.9)Be+^(238)Umeas-ured in two experiments are applied to constrain model calculations further through three codes,i.e,HIVAP2,KEWPIE2,and CCFULL.Parameters in these codes are also examined by comparison with measured fusion cross sections.AIll the comparisons indicate that the K EWPIE2 calculations using the WKB approximation agree well with the measured cross sections of both fusion reactions 7.9 Be+^(238)U and the fusion-evaporation reaction 238U(9 Be,5n)242 Cm.Calculations using the fusion code CCFULL are also in good agreement with the measured fusion cross sections of 7.9 Be+^(238)U.