Gamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency and therefore energy. Gamma rays are ionizing radiation and are thus biologically hazardous. Gamma rays are classically produced by the decay from high energy states of atomic nuclei (gamma decay), but also in many other ways. Natural sources of gamma rays on Earth include gamma decay from naturally-occurring radioisotopes such as potassium-40, and also as a secondary radiation from various atmospheric interactions with cosmic ray particles. Some rare terrestrial natural sources that produce gamma rays that are not of a nuclear origin, are lightning strikes and terrestrial gamma-ray flashes, which produce high energy emissions from natural high-energy voltages. Gamma rays are produced by a number of astronomical processes in which very high-energy electrons are produced. Such electrons produce secondary gamma rays by the mechanisms of bremsstrahlung, inverse Compton scattering and synchrotron radiation. A large fraction of such astronomical gamma rays are screened by Earth's atmosphere and must be detected by spacecraft. Notable artificial sources of gamma rays include fission such as occurs in nuclear reactors, and high energy physics experiments, such as neutral pion decay and nuclear fusion.
Heres an explanation of the phenomena occuring on earth...
The asexualization of our plant system , degraded by gamma rays and forced into a rare phenomena now noticed and puzzling scientist...
> We are wrestling to explain the finding that recently derived
> nematodal clades have a significant higher rate of evolution that
> older clades (Relative rate tests). In fact, we witness an increase in
> evolutionary rate
from primitive clades towards more recently derived
If not corrected, the long branches may cause LBA artefacts. In ML and NJ: =
run analyses always with a gamma distribution...
1. Can anyone help us in finding an explanation for this phenomenon ?
> (e.g. relevant articles/opinions/vicariance/life hostory traits ?) 2.
> Do we have to correct for this in a phylogenetic analysis (in
> MP/Bayesian/NJ trees) ?
> Best regards,
> Andre van der Wurff
Is it also obvious from the phylogenetic trees? Which gene(s) or DNA fragme=
nts did you use? May the acceleration of evolutionary rates indicate specia=
Often an acceleration of substitution rates was accompanied by a change in =
life style, e.g. a change from free-living to endosymbiontic life style, a =
change from photosynthesis to heterotrophy etc. In endosymbionts and organe=
lles also a bias toward increased A+T contents was found.
Are these younger nematodal lineages endosymbiotic, did they change habitat=
=3D , did they become asexual