نتایج جستجو برای: plant anatomy

تعداد نتایج: 483752  

Journal: :Molecular biology and evolution 1995
N Takezaki A Rzhetsky M Nei

To estimate approximate divergence times of species or species groups with molecular data, we have developed a method of constructing a linearized tree under the assumption of a molecular clock. We present two tests of the molecular clock for a given topology: two-cluster test and branch-length test. The two-cluster test examines the hypothesis of the molecular clock for the two lineages create...

Journal: :Genetics 2017
Luca Ferretti Alice Ledda Thomas Wiehe Guillaume Achaz Sebastian E Ramos-Onsins

We investigate the dependence of the site frequency spectrum on the topological structure of genealogical trees. We show that basic population genetic statistics, for instance, estimators of θ or neutrality tests such as Tajima's D, can be decomposed into components of waiting times between coalescent events and of tree topology. Our results clarify the relative impact of the two components on ...

2015
Zhen Zhu Michelangelo Puliga Federica Cerina Alessandro Chessa Massimo Riccaboni

The fragmentation of production across countries has become an important feature of the globalization in recent decades and is often conceptualized by the term "global value chains" (GVCs). When empirically investigating the GVCs, previous studies are mainly interested in knowing how global the GVCs are rather than how the GVCs look like. From a complex networks perspective, we use the World In...

  Urban pollution is a major environmental concern, especially in large cities in developing countries.MARKAZY province is one of the industrial provinces of the country that has the high air pollution due to Industrial structures. Study of structural and functional responses of Fraxinus excelsior to air pollutants was the objective of this research. Using data from the Environmental Prote...

Background and purpose: Anatomy is a branch of science that deals with different parts of human body and its organizational structure. It has various goals, such as insight into the divine perfection and understanding the causes of diseases and their treatments. Anatomy in the Islamic era included physiology too. This research aimed at providing an overview on anatomy in the Reference Materials...

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