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

-
Image
  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...
Post a Comment

EURO AT THE TURNING POINT

-


"The Commission would of course have preferred an outcome closer to its original proposal" said President of the European Commission José Manuel Barroso" adding however that the deal "can still be an important catalyst for growth and jobs".

This welcome agreement on the intra-union funding hides some bitter end.
Discordant opinions about the horizon of the Euro Zone (EZ) are growing all around Europe . For example, prof. Paolo Manasse, University of Bologna, expressed his criticism [read article] by arguing that the transfer of funds, which are necessary to keep on the EZ, is too huge.

The french economist Jacqes Sapir estimates that this transfer intra EZ amounts to 257 billion of euro !! But this amount does not include the ordinary intra-area transfer. In other terms, it sounds economically and politically not sustainable
 [read article].   


The spanish economist Julián Pavón (Catedrático - Director de CEPADE, Madrid) explains clearly the "schizofrenia" of the EZ: in front of the EZ crisis which is characterized by the depression of the global demand, the opportune actions should be adressed to increase the final consumption and/orthe investments and/or the public expenditure and/or the net export. But the current politics of deflation which the EZ countries have adopted are driving to the "wrong" direction. Instead of facilitating the convergence of the macroeconomic parameters among the EZ countries, they are reinforcing the disruptive forces.

"Since the it is not feasible to  sustain the countries which are in deep water by means of robust transfer of funds, then it is time to wonder if it is better for the heterogeneous countries of the EZ to walk apart." This is by the end the opinion of another italian economist which stands out from the crowd, prof. Alberto Bagnai, University of Pescara and researcher at the Centre de Recherche en Economie Appliquée à la Mondialisation (CREAM), University of Rouen (France). 


Comments

Post a Comment

Popular posts from this blog

Understanding Anaerobic Threshold (VT2) and VO2 Max in Endurance Training

-
Image
  Introduction: The Science Behind Ventilatory Thresholds VT1 vs. VT2: Defining Energy Transitions p (Aerobic Threshold) : The transition from lipid metawwwpp (fat-burning) to a mixed metabolism, where both carbohydrates and fats fuel muscle activity. V0T2 (Anaerobic Threshold) : The point where the  shifts to a predominantly carbohydrate-based wmetabolism , leading to rapid lactate waccumpulation and increased reliance on anaerobic energy pathways. www w In p VT1 and VT2 Wwww ewAgep & Sex Younger athletes generally exhibit higher VT2 values , while aging naturally reduces aerobicw capacity. Men tend to have a higher VO2 Max due to greater lung capacity and muscle mass, but women can achieve similar endurance levels through optimized training. Body Composition & Health Status High body fat percentage may reduce VT2 efficiency, as excess weight increases ...
Read more

Owen's Function: A Simple Solution to Complex Problems

-
Definition   If you are interested in statistics or probability, you may have encountered the Owen's function , a special function that arises in various applications involving bivariate normal distributions. Let’s explain what Owen's function is, how it is defined and notated, and why it is useful.  The Owen's function is defined as follows: for any real numbers h and a, Owen's function T(h,a) is given by T ( h , a ) = 1 2 π · ∫ 0 a exp ( - h 2 2 · ( 1 ...
Read more

Cell Count Analysis with cycleTrendR

-
Image
  1. Introduction Long‑term monitoring of adherent cell cultures (e.g., Vero, MDCK) is central to vaccine development, viral propagation, and QC workflows in CRO environments. Standard analyses typically focus on short‑term growth metrics such as doubling time, confluence progression, and endpoint viability. While informative, these metrics overlook slow drifts, cyclic environmental influences, and structural transitions that emerge over multi‑day or multi‑week monitoring. Operational routines (e.g., weekly medium changes), environmental oscillations (e.g., daily temperature cycles), and metabolic rhythms can introduce periodic components into cell‑density trajectories. These patterns are rarely analyzed explicitly, despite their potential impact on viral yield, infection kinetics, and batch‑to‑batch reproducibility. This post demonstrates how cycleTrendR can extract long‑term trends, dominant cycles, and structural transitions from a realistically simulated adherent cell‑co...
Read more