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Evrim Ağacı - Karanlığı bilimle fethet!Moleküler evrim hızı, bir popülasyon içerisinde DNA veya protein dizilerindeki mutasyon ların ne sıklıkla sabitlendiğini (yani popülasyondaki bireylerin çoğunda gözlendiğini) ölçer. Mutasyon hızı ise belirli bir zaman aralığında DNA veya protein dizisinde meydana gelen değişim miktarını tanı mlar. Birbirine sıkı sıkıya bağlı bu iki kavram, moleküler evrim anlayışımızın temelini oluşturur.
Örneğin moleküler saat kuramı (Zuckerkandl ve Pauling 1962), zaman ilerledikçe bir protein dizisinde sabitlenen amino asit mutasyonlarının miktarının da artacağını öngörür. Bu durumda, eğer mutasyon hızının belirli bir proteinin evrimsel soy hatları boyunca aynı olduğu varsayılırsa, moleküler evrim hızının da sabit olması beklenir (Görsel 1).
SpaceX launched another set of its Starlink internet satellites from southern California on Saturday evening (Feb 22).
A Falcon 9 rocket carrying 22 Starlink spacecraft lifted off from Vandenberg Space Force Station at 8:38 p.m. EST (5:38 p.m. local time or 0138 GMT Feb. 23).
As to plan, the Falcon 9's first stage came back to Earth about eight minutes after liftoff. It touched down on the drone ship "Of Course I Still Love You," which was stationed in the Pacific Ocean.
The Falcon 9's upper stage, meanwhile, continued to haul the Starlink satellites to low Earth orbit (LEO), where there were to be deployed about 62 minutes after liftoff.
The Starlink megaconstellation ⁘ the biggest ever assembled ⁘ currently consists of more than 7,000 operational spacecraft, according to astrophysicist and satellite tracker Jonathan McDowell.
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Robert Pearlman is a space historian, journalist and the founder and editor of collectSPACE.com , a daily news publication and community devoted to space history with a particular focus on how and where space exploration intersects with pop culture. Pearlman is also a contributing writer for Space.com and co-author of "Space Stations: The Art, Science, and Reality of Working in Space⁘ published by Smithsonian Books in 2018.In 2009, he was inducted into the U.S. Space Camp Hall of Fame in Huntsville, Alabama. In 2021, he was honored by the American Astronautical Society with the Ordway Award for Sustained Excellence in Spaceflight History. In 2023, the National Space Club Florida Committee recognized Pearlman with the Kolcum News and Communications Award for excellence in telling the space story along the Space Coast and throughout the world.
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