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Complejidad. G eo fi sic a. Biología. MacroEconomía. Psicologia. M eteorolog ía. E colog ía. Dante R. Chialvo Email: dchialvo@ucla.edu www.chialvo.net. Siempre que vemos Complejidad vemos No-Uniformidad.
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Complejidad Geofisica Biología MacroEconomía Psicologia Meteorología Ecología Dante R. Chialvo Email: dchialvo@ucla.edu www.chialvo.net
Siempre que vemos Complejidad vemos No-Uniformidad P (kilos) Log P ($) kilos Log($) Complejidad es igual a No-Uniformidad La estadistica que aprendimos describe la uniformidad (gaussianas) La naturaleza es NO HOMOGENEA!!!, por donde se la mire Ejemplo: distribución de peso versus distribución de pesos $ “muchas formas” “una forma”
“Fractals” Que son? Como estudiarlos? por que nos pueden importar? Material extraido del libro “Introduction to Fractals” Larry S. Liebovitch Lina A. Shehadeh
How fractals CHANGE the most basic ways we analyze and understand experimental data.
El universo es Fractal http://pil.phys.uniroma1.it/debate.html
Non - Fractal Size of Features 1 cm 1 characteristic scale
Fractal Size of Features 2 cm 1 cm 1/2 cm 1/4 cm many different scales
Fractals “Self-Similarity” Auto-similaridad
Self-Similarity • Pieces resemble the whole. Water Water Water Land Land Land
Branching Patterns air ways blood vessels in the retina in the lungs Family, Masters, and Platt 1989 Physica D38:98-103 Mainster 1990 Eye 4:235-241 West and Goldberger 1987 Am. Sci. 75:354-365
PDF - Probability Density Function HOW OFTEN there is THIS SIZE Straight line on log-log plot = Power Law
Statistical Self-Similarity The statistics of the big pieces is the same as the statistics of the small pieces.
Currents Through Ion Channels ATP sensitive potassium channel in cell from the pancreas Gilles, Falke, and Misler (Liebovitch 1990 Ann. N.Y. Acad. Sci. 591:375-391) FC = 10 Hz 5 sec 5 pA FC = 1k Hz 5 msec
Closed Time Histograms potassium channel in the corneal endothelium Liebovitch et al. 1987 Math. Biosci. 84:37-68 Number of closed Times per Time Bin in the Record Closed Time in ms
Closed Time Histograms potassium channel in the corneal endothelium Liebovitch et al. 1987 Math. Biosci. 84:37-68 Number of closed Times per Time Bin in the Record Closed Time in ms
Closed Time Histograms potassium channel in the corneal endothelium Liebovitch et al. 1987 Math. Biosci. 84:37-68 Number of closed Times per Time Bin in the Record Closed Time in ms
Closed Time Histograms potassium channel in the corneal endothelium Liebovitch et al. 1987 Math. Biosci. 84:37-68 Number of closed Times per Time Bin in the Record Closed Time in ms
Fractals Scaling
Scaling The value measured depends on the resolution used to do the measurement.
How Long is the Coastline of Britain? Richardson 1961 The problem of contiguity: An Appendix to Statistics of Deadly Quarrels General Systems Yearbook 6:139-187 AUSTRIALIAN COAST 4.0 CIRCLE SOUTH AFRICAN COAST Log10 (Total Length in Km) 3.5 GERMAN LAND-FRONTIER, 1900 WEST COAST OF BRITIAN 3.0 LAND-FRONTIER OF PORTUGAL 3.5 1.0 2.0 3.0 1.5 2.5 LOG10 (Length of Line Segments in Km)
Genetic Mosaics in the Liver P. M. Iannaccone. 1990. FASEB J. 4:1508-1512. Y.-K. Ng and P. M. Iannaccone. 1992. Devel. Biol. 151:419-430.
k in Hz eff effective kinetic rate constant 70 pS K+ ChannelCorneal Endothelium Liebovitch et al. 1987 Math. Biosci. 84:37-68. 1000 1-D k = A t eff eff 100 10 1 1 10 100 1000 effective time scale t in msec eff
Fractal Approach New viewpoint: Analyze how a property, the effective kinetic rate constant, keff, depends on the effective time scale, teff, at which it is measured. This Scaling Relationship: We are using this to learn about the structure and motions in the ion channel protein.
Scaling scaling relationship: much more interesting one measurement: not so interesting one value Logarithm of the measuremnt Logarithm of the measuremnt slope Logarithm of the resolution used to make the measurement Logarithm of the resolution used to make the measurement
Fractals Statistics
Gaussian Bell Curve “Normal Distribution”
Non - Fractal Mean pop More Data
The Average Depends on the Amount of Data Analyzed each piece
Ordinary Coin Toss Toss a coin. If it is tails win $0, If it is heads win $1. The average winnings are: 2-1.1 = 0.5 1/2 Non-Fractal
St. Petersburg Game (Niklaus Bernoulli) Toss a coin. If it is heads win $2, if not, keep tossing it until it falls heads. If this occurs on the N-th toss we win $2N. With probability 2-N we win $2N. H $2 TH $4 TTH $8 TTTH $16 The average winnings are: 2-121 + 2-222 + 2-323 + . . . = 1 + 1 + 1 + . . . = Fractal
Non-Fractal Log avg density within radius r Log radius r
Fractal Meakin 1986 In On Growthand Form: Fractal and Non-Fractal Patterns in Physics Ed. Stanley & Ostrowsky, Martinus Nijoff Pub., pp. 111-135 Log avg density within radius r 0 .5 -1.0 -1.5 -2.0 -2.5 .5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 0 Log radius r
Electrical Activity of Auditory Nerve Cells Teich, Jonson, Kumar, and Turcott 1990 Hearing Res. 46:41-52 action potentials voltage time
Electrical Activity of Auditory Nerve Cells Teich, Jonson, Kumar, and Turcott 1990 Hearing Res. 46:41-52 Divide the record into time windows: Count the number of action potentials in each window: 2 6 3 1 5 1 Firing Rate = 2, 6, 3, 1, 5,1
Electrical Activity of Auditory Nerve Cells Teich, Johnson, Kumar, and Turcott 1990 Hearing Res. 46:41-52 Repeat for different lengths of time windows: 8 4 6 Firing Rate = 8, 4, 6