Vortex. Pathlines of fluid particles around the axis (dashed line) of an ideal irrotational vortex. (See animation) Plughole Vortex In fluid dynamics, a vortex is a region within a fluid where the flow is mostly a spinning motion about an imaginary axis, straight or curved. That motion pattern is called a vortical flow. (The original and most common plural of "vortex" is vortices, although vortexes is often used too.) Once formed, vortices can move, stretch, twist, and interact in complex ways. A moving vortex carries with it some angular and linear momentum, energy, and mass. In a stationary vortex, the streamlines and pathlines are closed. Properties Vorticity and expressed by the vector analysis formula , where is the nabla operator. The local rotation measured by the vorticity must not be confused with the angular velocity vector of that portion of the fluid with respect to the external environment or to any fixed axis.
Vorticity profiles Irrotational vortices All Videos. KEVIN KELLY is Senior Maverick at Wired magazine. He helped launch Wired in 1993, and served as its Executive Editor until January 1999. He is currently editor and publisher of the popular Cool Tools, True Film, and Street Use websites. His most recent books are Cool Tools, and What Technology Wants. Kevin Kelly's Edge Bio Page Introduction by John Brockman A few weeks ago David Carr profiled Kevin Kelly on page 1 of the New York Times Business section. For the thirty years I've known him, Kelly has been making bold declarations about the world we are crafting with new technologies.
The biggest change in our lives is the rate of change and it's interesting to note that this week marks the 10th anniversary of the 2004 founding of Facebook. Kelly's is well aware that his complete embrace of what he calls "The Technium", is a lightning rod for criticism. The Snowstorm finale by Slava. Amélie Nothomb. Amélie Nothomb. Amélie Nothomb (Etterbeek, Bélgica, 9 de julio de 1966) es una escritora belga en lengua francesa.
Debido a la profesión de su padre, diplomático de Bélgica, vivió, además de en Japón, en China, los Estados Unidos, Laos, Birmania y Bangladés. Habla japonés y trabajó como intérprete en Tokio. Desde 1992, ha publicado una novela cada año. Amélie ha vivido en muchos sitios, encuentra el horror de la guerra y la pobreza, se refugia en el mundo dorado de la infancia, junto a su hermana mayor, de la que permanece muy próxima. A los diecisiete años descubre Europa y más precisamente Bruselas, ciudad en la que se siente extraña y extranjera. Estudia filología románica en la Universidad Libre de Bruselas, pero su apellido evoca en Bélgica a una familia de la alta burguesía católica y a un bisabuelo de extrema derecha, lo que no favorece su integración en una universidad de tendencias liberal-socialistas (sobre ello escribió una novela semi-biográfica, Antichrista).
Drop in IQ linked to heavy teenage cannabis use. Imagebrokers/Photoshot Heavy marijuana use at a young age can significantly lower a person's IQ. Becoming a heavy cannabis smoker as a teenager results in cognitive decline not seen if the illicit drug use starts when adult. Clinical psychologist Madeline Meier at Duke University in Durham, North Carolina, and her colleagues used data from the famous Dunedin Longitudinal Study, an ongoing multi-factor survey involving a cohort of 1,037 New Zealanders followed from birth, which now has 40 years worth of data. Participants in the Dunedin Study had been periodically tested for IQ and other neuropsychological indices as well as being asked about behaviour such as drug-taking.
The study was published in the Proceedings of the National Academy of Sciences on Monday1. When their adult IQ was tested at 38 years old, the heaviest and most persistent adolescent-onset users in the study had experienced an average decline of eight IQ points from childhood to adulthood. Rich data Study limitations.
How the brain cleans itself. J. Iliff and M. Nedergaard Channels carry a cleansing fluid through the brain. An article from Scientific American. The brain can be a messy place. Thankfully, it has good plumbing: Scientists have just discovered a cleansing river inside the brain, a fluid stream that might be enlisted to flush away the buildup of proteins associated with Alzheimer's, Huntington's and other neurodegenerative disorders. The researchers, based at the University of Rochester (U.R.), University of Oslo and Stony Brook University, describe this new system in the journal Science Translational Medicine.
In most of the body, a network of vessels carry lymph, a fluid that removes excess plasma, dead blood cells, debris and other waste. In this study, researchers led by U.R. neuroscientist Maiken Nedergaard have identified a second, faster brain-cleansing system. Nedergaard and colleagues studied live mice with holes drilled into their skulls to gain an unobstructed view. Future - Technology - The decaying web and our disappearing history. Our online history is disappearing at an astonishing rate, creating a black hole for future historians. On January 28 2011, three days into the fierce protests that would eventually oust the Egyptian president Hosni Mubarak, a Twitter user called Farrah posted a link to a picture that supposedly showed an armed man as he ran on a “rooftop during clashes between police and protesters in Suez”.
I say supposedly, because both the tweet and the picture it linked to no longer exist. Instead they have been replaced with error messages that claim the message – and its contents – “doesn’t exist”. Few things are more explicitly ephemeral than a Tweet. Yet it’s precisely this kind of ephemeral communication – a comment, a status update, sharing or disseminating a piece of media – that lies at the heart of much of modern history as it unfolds.
It’s also a vital contemporary historical record that, unless we’re careful, we risk losing almost before we’ve been able to gauge its importance.