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Showing posts from July, 2013

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...
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Ocular-Motor Profile and Effects of Memantine in a Familial Form of Adult Cerebellar Ataxia with Slow Saccades and Square Wave Saccadic Intrusions

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This study [ here ] suggests that  memantine may have some general suppressive effect on saccadic intrusions , including both  square wave intrusions (SWI)   and  macrosaccadic oscillations  ( MSO), thereby restoring the capacity of reading and visual attention in these and in other recessive forms of ataxia, including Friedreich’s, in which saccadic intrusions are prominent.     Two patients ( two sisters with identical phenotype ) with an unrecognized, probably recessive hereditary form of adult-onset cerebellar ataxia clinically characterized by axonal sensory neuropathy, cerebellar atrophy, slow saccades and prominent  square wave intrusions , have been treated  with the drug memantine,  which is an uncompetitive antagonist of the NMDA-receptor (NMDAR)  [1] . The aim was to suppress frequent and large saccadic intrusions.  Fixation instability due to saccadic intrusions is a feature of autosomal recessive spinoce...
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PERSPECTIVES ON DETROIT

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The failure of Detroit can not go unnoticed. The main causes and potential side effects have been reported [ here ] and [ here ] . Let's see now the point of view of professor Stephen Cohen .   Stephen Cohen teaches economics at the University of Berkeley [1] . Specialist of urban economy and territory, after the failure of the city of Detroit answers some questions at the information portal Liberation.fr [ here ] . 1. What is the importance of this failure of American scale? It 's the worst failure of a local authority ever made in the United States from the years of the Second World War. The debt of the city is 20 billion dollars. A considerable sum, but it is not a surprise. Once Detroit was the fourth largest city in the country. Since 1950, has lost half of its inhabitants. Today it has 700,000, versus 1.8 million over fifty years ago. They were the poorest, with a population of color equal to 80%. The real estate industry has collapsed, as well as tax reve...
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SIDE EFFECTS OF THE FAILURE OF DETROIT

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The financial failure of the city of Detroit [ here ] will also have consequences on some European banks, exposed towards the debt contracted by the American metropolis. Among the banks involved there is also UBS : in 2005 the bank was handling the sale of $ 1.4 billion of municipal bonds. Operations conducted on behalf of the administration of Detroit, to enable it to finance its pension fund. Similar operations involving other banks - for a total of another billion dollars - and these include many institutions that already live in conditions of difficulty. As in the case of the "bad bank" of Hypo Real Estate , which is the most exposed with $ 200 million, to Commerzbank , which owns a total of 4.5 billion euro in American local governments, or Deutsche Bank , not involved however excessively.
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DETROIT BANKRUPTCY

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And so Detroit has gone bankrupt.  The news of the failure of a (former) major American city, an event of far greater importance than that of the city of San Bernardino (CA), the Boise County (IH) or Jefferson County (AL). The greater severity of the failure of Detroit stems not only from total size of the debt, but also the origin of the structural debt: while in other cases the trigger for the crisis was a limited negative event, such as severe errors in the management of the debt or investment, in the case of Detroit instead the causes are structural and inherent in the evolution of the city itself . Demographic decline . The city went from having 1,849,000 inhabitants in 1950 to just over 700,000 today. Pretty much the city has had a reduction of two thirds of the inhabitants. Why do people have fallen so substantially? The City's economy was based on a  single industry . Detroit was the city of cars, home of the three majors of the automotive industry and a ...
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The coffers of the central banks are empty. The collapse of the price of gold has been planned

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Eric Sprott , fund manager [1] , argues that the current collapse in the value of gold has been long planned by the central banks of the United States and Europe, to take advantage of low prices and fill bullion safes now empty. According to Sprott, the coffers of Western central banks are empty and since the news should not have been disclosed, here that was organized a reduction in demand for gold in a very short period of time. At first brokers and western commercial banks have advised clients to sell gold. The institutions themselves have held their positions 'short' bearish on the COMEX. When bidding for the benchmark price of the precious metal has surged, the statements about a reduction in the extent of monetary easing measures by the helmsmen of the lead institutions did the rest, driving down the prices.  Speculators such as hedge funds have opened an avalanche of short positions, futures markets have suffered a blow on the metal and gold stocks are at all-time lo...
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ECONOMIC RECOVERY IS KEPT WAITING IN ITALY

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Bank of Italy announced [ Economic Bulletin No. 69 ] that the country is  facing a new record for the general government debt in May that reaches € 2.0746 trillion , an increase of € 33.4 billion from the previous month, and about  €100 of May 2012. In the first five months of 2013, the tax revenue totaled 143.171 billion euro, 0.7% more than in January-May 2012. The increase in the public debt, mainly reflects the increase of € 20.4 billion in cash of the Treasury (which reached € 62.4 billion, compared to € 35.8 in the month of May of 2012) and the general government borrowing requirement of the month (€ 11.5 billion). In May, the share of the Italy of the EFSF loans was € 2.9 billion (in total this share has reached € 30.9 billion). In the first five months of the year the increase in debt (€ 86.1 billion) largely reflects the requirements of the government (€ 58.1 billion) and the increase in cash and cash equivalents of the Treasury (€ 28.0 billion). ...
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GLOBAL WARMING: LONG TERM ANALYSIS

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The Obama Administration is trying to enhance environment-friendly policy decisions [1] .  " President Obama has announced a series of executive actions to reduce carbon pollution , prepare the U.S. for the impact of climate change and lead international efforts to address global climate change . " [ here ] This sentence confirms the turn of the U.S. policy on the environment protection issue. It focuses on the carbon pollution, states the condition of climate change (fait accompli) and the necessity for making all the efforts for dealing with the future consequences, and finally raises the U.S. as a leader-country in this "battle". Implicitly, the information which it conveys, sounds as if there exists a direct relationship between the emission of carbon dioxide and the global climate change, where global climate change stands for global warming  [ here ] Therefore, by controlling the carbon pollution one would expect the lowering of the global tem...
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Understanding Anaerobic Threshold (VT2) and VO2 Max in Endurance Training

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  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 ...
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Owen's Function: A Simple Solution to Complex Problems

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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 ...
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Cell Count Analysis with cycleTrendR

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  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...
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