What is Brownian motion?

submitted by: peter.krautzberger

This is a talk by Plamen Turkedjiev of Freie Universität Berlin / Berlin Mathematical School, given at the "What is ...?" seminar at the Freie Universität Berlin on February 13, 2009, https://www.math.fu-berlin.de/w/Math/WhatIsSeminar .

Tour de Sys: The Traveler's View of a Network

submitted by: christian.thiemann

Analyzing the structure of complex networks like the US Aviation System can be very difficult, but one way to simplify this problem is to consider only the flights on the shortest routes from one specific airport to every other. For each airport, this gives us a different perspective on the network from which we can examine its statistical properties.

What Genomes Can Tell Us About the Past by Sydney Brenner - Part 2: (42:36)

submitted by: video_collector

In the second part of talk, I explore other clues that suggest that genomes are not at equilibrium. Some genes appear to be changing more slowly and these older "fossil" genes in modern day genomes may give us insight into the distant past. I also hope to convince you that many of the great mysteries in contemporary biology do not require big research labs but can be solved through "home genomics"- piecing together information through a computer, the internet, and an inquisitive mind.

The Origin of Vertebrates - Part 3: How Chordates Got Their Chord (19:09)

submitted by: video_collector

In Part 3: How chordates got their chord, Marc Kirschner (Harvard Medical School) discusses how the overall body plan of vertebrates, arose from the invertebrates based on knowledge of the commonalities in their developmental mechanisms. Here again, the acorn worm, offers the key comparison, being close enough to us to share some recognizable features, but far enough away to indicate the direction from whence we came.

Role of the Neural Crest in Vertebrate Development and Evolution: Part 3: The Molecular Control of the Neural Crest Contribution to Craniofacial and Brain Development (36:10)

submitted by: video_collector
Further studies have shown that the NC cells which participate in facial skeletogenesis correspond to the anteriormost region of the body axis where the genes of the Hox cluster are not expressed. If the forced expression of Hoxa2, Hoxa3 and Hoxb4 (the most anteriorly expressed Hox genes) is induced in this part of the neural fold, brain development is deeply affected with anencephaly and no skeletogenesis takes place in the face which fails to develop. This phenotype is reproduced when the...

The Problem of Regeneration: Part 3: Molecular Basis of Regeneration: Planarians as a Model System (43:54)

submitted by: video_collector

In the third and last part of this lecture, I will introduce the model system we have developed to study animal regeneration, the planarian Schmidtea mediterranea. I will review its anatomy, and the biological attributes that make these animals extraordinarily well suited to dissect the molecular and cellular basis of regeneration. I will also discuss recent work from my laboratory aimed at identifying molecules associated with regenerative capacities.