Las matemáticas explican por qué los ríos forman afluentes. Un estudio publicado esta semana en Nature propone una teoría matemática para explicar por qué los ríos se ramifican creando afluentes. Los autores muestran que el patrón de ramificación de las redes fluviales está controlado por dos inestabilidades acopladas en el proceso de erosión del suelo. Taylor Perron, autor principal del trabajo, explica a SINC estas inestabilidades: “Imaginemos una serie de valles de aproximadamente el mismo tamaño, excepto uno que es ligeramente mayor. Este tenderá a crecer más, porque puede recoger más agua y el flujo del río será mayor y erosionará el terreno más rápido. Pero al mismo tiempo el suelo que se mueve hacia abajo por las laderas tiende a llenar el valle y hace que este no crezca”. “Hemos descubierto un punto de inflexión matemático que determina si ese valle continuará creciendo o si se encogerá al tamaño de sus vecinos.
Esa es la primera inestabilidad”, apunta Perron. How the central limit theorem began. The Central Limit Theorem says that if you average enough independent copies of a random variable, the result has a nearly normal (Gaussian) distribution. Of course that’s a very rough statement of the theorem. What are the precise requirements of the theorem? That question took two centuries to resolve. You can see the final answer here. The first version of the Central Limit Theorem appeared in 1733, but necessary and sufficient conditions weren’t known until 1935.
A typical probability course might proceed as follows. This is the opposite of the historical order of events. Abraham de Moivre discovered he could approximate binomial distribution probabilities using the integral of exp(-x2) and proved an early version of the Central Limit Theorem in 1733. For more details, see The Life and Times of the Central Limit Theorem. Related links: Sums of uniform random variablesQuantifying the error in the central limit theoremThree central limit theorems. Política matemáticas. Política matemáticas Matemáticas ¡Comparte esto con tus contactos! (NC&T/Gaceta de la Real Sociedad Matemática Española) Desde la negación de la contribución árabe al álgebra hasta el nuevo enfoque de los científicos alemanes tras la Primera Guerra Mundial, influidos por la filosofía y la literatura del momento, los vaivenes políticos de las matemáticas han sido analizados por el alemán Norbert Schappacher en un artículo que publica La Gaceta de la Real Sociedad Española de Matemáticas.
"Las matemáticas son hijas de su tiempo", afirma Schappacher. Schappacher encuentra una primera muestra de interferencia en las matemáticas de los sucesos históricos en la Revolución Científica que tuvo lugar entre los siglos XV y XVII. De ese odio de los humanistas a lo árabe, que desfiguró la historia de las matemáticas, Schappacher salta a la Primera Guerra Mundial, tras la cual el propio contenido de esa ciencia fue politizado.
La forma de una coleta, un enigma matemático. Dan's Geometrical Curiosities - Explaining an Astonishing Slinky. Basics on Markov Chain (for parents) Markov chains is a very interesting and powerful tool. Especially for parents. Because if you think about it quickly, most of the games our kids are playing at are Markovian. For instance, snakes and ladders... It is extremely easy to write down the transition matrix, one just need to define all snakes and ladders. For the one above, we have, So, why is it important to have a Markov Chain ? Here, we have the following (note that I assume that once 100 is reached, the game is over) Assume for instance, that after 10 turns, your daughter accidentally drops her pawn out of the game. So, if she claims she was either on 58, 59 or 60, here are the theoretical probabilities to be in each cell after 10 turns, > h=10> (initial%*%powermat(M,h))[59:61]/+ sum((initial%*%powermat(M,h))[59:61])[1] 0.1597003 0.5168209 0.3234788 i.e. it is more likely she was on 59 (60th cell of the vector since we start in 0).
> sum(1-game)[1] 32.16499 i.e. in 33 turns, on average, your daughter reaches the 100 cell. Researchers find a country's wealth correlates with its collective knowledge. (PhysOrg.com) -- What causes the large gap between rich and poor countries has been a long-debated question. Previous research has found some correlation between a nation’s economic prosperity and factors such as how the country is governed, the average amount of formal education each individual receives, and the country's overall competiveness. But now a team of researchers from Harvard and MIT has discovered that a new measure based on a country's collective knowledge can account for the enormous income differences between the nations of the world better than any other factor.
The researchers, led by Ricardo Hausmann, director of Harvard’s Center for International Development and former Minister of Planning for Venezuela, and Cesar A. Hidalgo, assistant professor at MIT’s Media Laboratory and faculty associate at Harvard’s Center for International Development, have published a book called The Atlas of Economic Complexity. Explore further: Pseudo-mathematics and financial charlatanism. Clasificación Parcial II: Mejor Blog de Educación | Premios Bitacoras.
Index of fractal images (Fractal Gallery) Fractal World Gallery Thumbnails : cosmic recursive fractal flames or flame fractals. Fractal World Gallery contains a collection of Pure flame fractals, fractal flame composites, fractals, etc: established 1998 Flame Fractals date from 1998 to the Present. by Cory Ench © 2007 Images from this gallery may only be used with artist's permission Fractal software includes Frax Flame and Apophysis for cosmic recursive fractal flames.
FAQ I CONTACT I PRINTS More artwork by Cory Ench at www.enchgallery.com 164 images in room 7 click on the thumbnails for full view fractal image 164 images in room 7 120 images in room 6 120 images in room 5 120 images in room 4 120 images in room 3 132 images in room 2 120 images in room 1 Other non fractal art by Cory Ench at home Thanks for viewing the Fractal World Gallery. Please go to next gallery room for more cosmic recursive flame fractals. Don't forget to sign our guestbook and give some feedback. Sign Guestbook. Mathway: Math Problem Solver.