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Why Biological Systems Suddenly Change State: An Intuitive Guide to Freidlin–Wentzell Theory

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  Stochasticity is ubiquitous in biology and neuroscience, manifesting in various forms, including ion channel noise, synaptic variability, gene regulatory fluctuations, noisy population dynamics, and more. Many biological systems spend long periods in a stable “state” and only rarely transition to another state due to noise. For instance, a neuron typically remains inactive but may occasionally trigger a spontaneous spike. Similarly, a gene can switch from the OFF state to the ON state due to rare bursts of transcription factors. Cells can also transition out of metabolic or epigenetic states, populations might shift between different ecological equilibria, and a viral infection can fluctuate between phases of control and uncontrollability. Freidlin–Wentzell theory provides a mathematically rigorous framework to study these phenomena when noise is small but nonzero . It tells you, firstly, h ow likely rare transitions are,    secondly,   h ow fast they occ...

GLOBAL WARMING: THE 21ST CENTURY RELIGION!

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" When people stop believing in  orthodox religion, rather than believe in nothing, they believe in anything! "   [Gilbert Keith Chesterton, 1874 - 1936] Reading in the huffingtonpost  [ here ] the note of  Peter Lilley  on the climate change issue  it becomes plain how deceiving is the uncritical faith in  the Global Warming .  " One of the ersatz religions which fills the void in recent years is belief in Catastrophic Man-Made  Global Warming . It claims to be based on science. But it has all the characteristics of an eschatological cult "  [Peter Lilley] Neither statistical evidence nor the social-economic consequences of their model seem to move the global-warming followers from their theoretical assumption based on the direct relationship of the increase of the global temperature to  the raise of carbon dioxide emission. But gradually some criticism on this position  begin to make inroads.  ...

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