Systematic network lesioning reveals the core white matter scaffold of the human brain Introduction Brain lesions due to conditions such as traumatic brain injury (TBI), stroke and multiple sclerosis (MS) can have focal, region-specific consequences as well as diffuse effects upon cortical circuitry (Van Horn et al., 2012). For this reason, the ability to quantify injury-related connectomic changes in a systematic manner is critical for the evaluation of injury severity and for the personalization of treatment after neurotrauma. In both health and disease, network theory can provide essential insight into the structural properties of brain connectivity (Sporns, 2011), particularly by providing quantitative measures of lesion impact upon neural structure and function, with possible relevance to the prediction of clinical outcome variables and to the task of designing patient-tailored rehabilitation protocols (Irimia et al., 2012a,b). Materials and Methods Subjects and Data Acquisition Image Processing Connectivity Calculation Connectogram Design Figure 1. Network Measures
Miniature bouncing tennis balls reveal cellular interiors I admit it, I love my job(s). I love doing science, and I love reporting science. In particular, I love it when my expectations are confounded, as they recently were in a paper I read. What I found were results that are still a bit preliminary. Randomness generates a map Imagine that you want to explore a house. As you track the average location of the tennis balls, you map out the walls, beds, curtains, doors, and windows (the tennis balls that exit the window never return, as is often the case in real life). It turns out that you can do the same thing in a cell. It sounds great, but, in practice, you would be waiting a very long time to get that image. The key to this technique, though, is determining the particle position as accurately as possible as a function of time. A quantum locator To understand how the researchers improved their position detector, we need to understand a little bit about light. This is where quantum mechanics gives us a good kicking.
Urban Computing Reveals the Hidden City In his essay “Walking in the City,” the French scholar Michel de Certeau talks about the “invisible identities of the visible.” He is talking specifically about the memories and personal narratives associated with a location. Until recently, this information was only accessible one-to-one—that is, by talking to people who had knowledge of a place. But what if that data became one-to-many, or even many-to-many, and easily accessible via some sort of street-level interface that could be accessed manually, or wirelessly using a smartphone? This is essentially the idea behind urban computing, where the city itself becomes a kind of distributed computer. The pedestrian is the moving cursor; neighborhoods, buildings, and street objects become the interface; and the smartphone is used to “click” or “tap” that interface. Smartphone in hand, what can the modern-day flaneur expect to find in this newly digitized urban environment? Is the urban computer a good thing?
Self-Assembling Molecules Like These May Have Sparked Life on Earth - Wired Science When his students successfully converted chemical precursors into an RNA-like molecule in the form of a yellow gel, Nicholas Hud scribbled down the surprising recipe. Image: Nicholas Hud For Nicholas Hud, a chemist at the Georgia Institute of Technology, the turning point came in July of 2012 when two of his students rushed into his office with a tiny tube of gel. The contents, which looked like a blob of lemon Jell-O, represented the fruits of a 20-year effort to construct something that looked like life from the cacophony of chemicals that were available on the early Earth. To some biochemists, Hud’s attempts to find an evolutionary precursor to ribonucleic acid may have seemed a fool’s errand. The dominant theory to explain the origins of life — known as the RNA world hypothesis — regards ribonucleic acid as the first biological molecule. If RNA was indeed the first biological molecule, discovering how it first formed would illuminate the birth of life. From Soup to Structure
How Science Turned a Struggling Pro Skier Into an Olympic Medal Contender - Wired Science Saslong.org/R.Perathoner Steven Nyman is poised at the starting gate, alert, coiled, ready. A signal sounds: three even tones followed by a single, more urgent pitch, sending Nyman kicking onto the Val Gardena downhill ski course. He pushes five times with his poles, accelerating as quickly as possible, stabbing the snow frantically. He skates forward with abbreviated strokes, neon green boots moving up and down, his focus on building as much momentum as possible. Nyman is feeling good. In the world of downhill racing, Nyman, 30, is a grizzled journeyman, a fixture on the World Cup circuit who for most of his 11-year professional career has been stuck solidly in the middle of the pack. Until now. In the wake of a season-ending Achilles tear in 2011, Nyman embarked on a new training regimen. Hours in a Wind TunnelAround four seconds into the run, Nyman goes into his tuck—knees bent at 90-degree angles, back parallel to the ground, hands forward, head up. It was forged in a wind tunnel.
Nuclear fusion hits energy milestone - Technology & Science For the first time, fuel for a nuclear fusion reaction has generated more energy than put into it – a scientific milestone. Scientists and futurists have long dreamed of harnessing the energy of nuclear fusion, which powers the sun, here on Earth. An enormous amount of energy is released when multiple atoms collide and fuse to form a new, heavier atom — such as hydrogen fusing into helium. Hydrogen fuel is plentiful in sources such as seawater and the fusion process generates no radioactive waste, greenhouse gases or other dangerous byproducts. However, for decades, scientists have been unsuccessful in generating the conditions for making fusion happen on Earth in a controlled manner that would allow it to be used in power plants. Deuterium and tritium were coated inside the capsule at the centre of this photo, inside a cylindrical container. "That's a major turning point in our minds," said Omar Hurricane, lead author of a paper describing the results, published in Nature today.
Genes, Macromolecules, -&- Computing: Strange loops in biology Strange loops is a term introduced by Douglas Hofstadter in his seminal book, G"odel, Escher, Bach: An Eternal Golden Braid. Simply put, it refers to self-referential (recursive) constructs. For a more detailed explanation, read the book; hopefully the examples below will illustrate my thinking on strange loops. This is in progress. GEB ... likens inanimate molecules to meaningless symbol, and further likens selves (or "I"'s or "souls", if you prefer---whatever it is that distinugishes animate matter from inanimate matter) to certain special swirly, twisty, vortex-like, and meaningful patterns that arise only in particular types of systems of meaningless symbols. It is these strange, twisty patterns that the book spends so much time on, because they are little known, little appreciated, counterintiutive, and quite filled with mystery. The greatest strange loop in biology is the one where DNA is used to make proteins which in turn is used to make more DNA.
Gamme de Shepard Un article de Wikipédia, l'encyclopédie libre. où 16 < f < 32 De la sorte, la note de Shepard correspondant à la fréquence fondamentale f dans l'octave -1 confond toutes les notes de même nom dans toutes les octaves. Exemple d'un son de Shepard : Son de Shepard pour la note la. Le la-1 correspond à la fréquence 27,5 hertz. Le son de Shepard correspondant est la somme à égalité de toutes les sinusoïdes correspondant à la fréquence fondamentale de tous les la audibles, 27,5, 55, 110, 220, 440, 880, 1760, 3520, 7040 et 14 080 Hz. Gamme de Shepard, diatonique en Do majeur, repétée 5 fois. Quand la fondamentale parcourt en boucle en descendant ou en montant toutes les valeurs de l'octave -1, cela crée l'illusion auditive d'une gamme qui descend (ou monte) indéfiniment. Importance des sons et gamme de Shepard[modifier | modifier le code] La gamme de Shepard, en tant que perception paradoxale, peut se comparer à l'objet impossible appelé escalier de Penrose, pour la perspective[2]. ↑ (en) Roger N.
Shepard tone Spectrum view of ascending Shepard tones (linear frequency scale) Construction[edit] Figure 1: Shepard tones forming a Shepard scale, illustrated in a sequencer Each square in the figure indicates a tone, any set of squares in vertical alignment together making one Shepard tone. The acoustical illusion can be constructed by creating a series of overlapping ascending or descending scales. The scale as described, with discrete steps between each tone, is known as the discrete Shepard scale. Jean-Claude Risset subsequently created a version of the scale where the tones glide continuously, and it is appropriately called the continuous Risset scale or Shepard–Risset glissando. The tritone paradox[edit] Examples[edit] See also[edit] References[edit] External links[edit]