Small world by Ralph C. Merkle Xerox PARC 3333 Coyote Hill Road Palo Alto, CA 94304 merkle@xerox.com This is an extended web version of the article published in the Feb/Mar 1997 issue of MIT Technology Review. This version has greater technical detail and embedded links. Introduction Manufactured products are made from atoms. Since we first made stone tools and flint knives we have been arranging atoms in great thundering statistical heards by casting, milling, grinding, chipping and the like. That's changing. Build products with almost every atom in the right place. One warning: in contrast to the useage in this article some researchers use the word "nanotechnology" to refer to high resolution lithographic technology while others use it to refer to almost any research where some critical size is less than a micron (1,000 nanometers). There are two main issues in nanotechnology: What might molecular manufacturing systems look like? The advantages ofnanotechnology The advantages of positional control
4 Important Rare Earth Elements Sir William Crookes, a 19th century British chemist, once wrote that, "rare earth elements perplex us in our researches, baffle us in our speculations and haunt us in our very dreams." These weren't easy elements to isolate or to understand, and so there was a very long lag time between the discovery of the rare earths, and the discovery of practical uses for them. It didn't help that individual rare earth elements don't occur by their lonesome—they travel in packs. Europium was the first isolated, high purity rare earth element to enter the public marketplace, in 1967, as a source of the color red in TV sets. At the time, rare earth mining wasn't even a twinkle in China's eye. Today, europium is still used as a phosphor, but as cathode ray tube TVs go the way of the dodo, it's more likely to turn up in white LED-based lights, which could someday be an energy efficient replacement for both incandescent and compact fluorescent bulbs.
The Biomechanics of Good Running | Playbook AUSTIN, Texas — If you’re a runner and you can’t extend your hip well behind you on your stride, Jay Dicharry has bad news: You’re never going to be a great runner. [bug id="sxsw2012"]This doesn’t mean you should hang up your shoes. You can still run, and run well, but not everyone can attain the ideal stride needed to be a truly great runner. Dicharry is the director of the Speed Performance Clinic and the Motion Analysis Lab Coordinator At The University Of Virginia. “I’m from New Orleans, and there’s great food there,” he said, by way of understatement. Most runners don’t extend their hips, Dicharry said. Along with a lack of hip extension, overstriding is one of the biggest sins. Even elite athletes can fall prey to these pitfalls in form, as Dicharry demonstrated with a tape of the mens’ 800-meter finals at the 2011 NCAA outdoor track and field championships. “Look at their gait,” he said. “There’s more to it than just running,” Dicharry said of winning. Third, kneel on one knee.
Open Source Physics Computational Resources for Teaching The OSP Collection provides curriculum resources that engage students in physics, computation, and computer modeling. Computational physics and computer modeling provide students with new ways to understand, describe, explain, and predict physical phenomena. Browse the OSP simulations or learn more about our tools and curriculum pieces below. Tracker The Tracker tool extends traditional video analysis by enabling users to create particle models based on Newton's laws. Learn more about Tracker Curriculum Packages OSP curriculum packages combine computer simulations with tutorial materials and student worksheets. Browse curriculum resources by topic and learn how to customize packages Featured Curriculum Package Ghostly Images JS Package The Ghostly Images Package contains Javascript models and worksheets for 1D kinematics to illustrate the connection between motion diagrams ("ghostly images") and position-time plots. EJS Modeling Learn more about EJS Tools
Motion Mountain - The Free Physics Textbook for Download The Science Behind Foldit Foldit is a revolutionary new computer game enabling you to contribute to important scientific research. This page describes the science behind Foldit and how your playing can help. What is a protein? Proteins are the workhorses in every cell of every living thing. Your body is made up of trillions of cells, of all different kinds: muscle cells, brain cells, blood cells, and more. Inside those cells, proteins are allowing your body to do what it does: break down food to power your muscles, send signals through your brain that control the body, and transport nutrients through your blood. What are amino acids? What shape will a protein fold into? Why is shape important? What do proteins do? Proteins are present in all living things, even plants, bacteria, and viruses. Photosystem I is a collection of proteins in plants that captures sunlight for photosynthesis.Luciferase catalyzes the chemical reaction that makes fireflies glow.Hemagglutinin helps the influenza virus invade our cells.
25 Acts of Body Language to Avoid Our body language exhibits far more information about how we feel than it is possible to articulate verbally. All of the physical gestures we make are subconsciously interpreted by others. This can work for or against us depending on the kind of body language we use. Some gestures project a very positive message, while others do nothing but set a negative tone. Most people are totally oblivious to their own body language, so the discipline of controlling these gestures can be quite challenging. Most of them are reflexive in nature, automatically matching up to what our minds are thinking at any given moment. Nevertheless, with the right information and a little practice, we can train ourselves to overcome most of our negative body language habits. Practice avoiding these 25 negative gestures: “ I speak two languages, Body and English. ” — Mae West Holding Objects in Front of Your Body – a coffee cup, notebook, hand bag, etc. Want to know powerful, dominant, confident body language postures?
Molecular Library [ About the Database ] Links to Other Molecular Databases K-12 Resources EDinformatics- Contains a large number of information databases. Also has an excellent Math and Science Section Physics 2000 Physics 2000, is an interactive journey through modern physics! For more info, email: mr23@nyu.edu The Energy Story Energy is one of the most fundamental parts of our universe. We use energy to do work. Energy lights our cities. Energy powers our vehicles, trains, planes and rockets. Energy warms our homes, cooks our food, plays our music, gives us pictures on television. Energy from the sun gives us light during the day. Everything we do is connected to energy in one form or another. Energy is defined as: "the ability to do work." When we eat, our bodies transform the energy stored in the food into energy to do work. Cars, planes, light bulbs, boats and machinery also transform energy into work. Work means moving something, lifting something, warming something, lighting something. There are many sources of energy. The forms of energy we will look at include: Electricity Biomass Energy - energy from plants Geothermal Energy Fossil Fuels - Coal, Oil and Natural Gas Hydro Power and Ocean Energy Nuclear Energy Solar Energy Wind Energy Transportation Energy
Misuse of statistics A misuse of statistics occurs when a statistical argument asserts a falsehood. In some cases, the misuse may be accidental. In others, it is purposeful and for the gain of the perpetrator. When the statistical reason involved is false or misapplied, this constitutes a statistical fallacy. The false statistics trap can be quite damaging to the quest for knowledge. Misuses can be easy to fall into. Types of misuse[edit] Discarding unfavorable data[edit] All a company has to do to promote a neutral (useless) product is to find or conduct, for example, 40 studies with a confidence level of 95%. Another common technique is to perform a study that tests a large number of dependent (response) variables at the same time. Loaded questions[edit] The answers to surveys can often be manipulated by wording the question in such a way as to induce a prevalence towards a certain answer from the respondent. Do you support the attempt by the USA to bring freedom and democracy to other places in the world? .
Common statistical fallacies I've been reading papers on how people learn statistics (and thoughts on teaching the subject) and came across the frequently-cited work of mathematical psychologists Amos Tversky and Daniel Kahneman. In 1972, they studied statistical misconceptions. It doesn't seem much has changed. Joan Garfield (1995) summarizes in How to Learn Statistics [pdf]. Representativeness: People estimate the likelihood of a sample based on how closely it resembles the population. You can't always judge how likely or improbable a sample is based on how it compares to a known population. Similarly, a sequence of ten heads in a row isn't the same as getting a million heads in a row. Gambler's fallacy: Use of the representative heuristic leads to the view that chance is a self-correcting process. The history boards at roulette tables mean nothing. Base-rate fallacy: People ignore the relative sizes of population subgroups when judging the likelihood of contingent events involving the subgroups. Availability:
Pseudoreplication Pseudoreplication, as originally defined[1] , is a special case of inadequate specification of random factors where both random and fixed factors are present.[2] The problem described by this term arises when treatments are assigned to units that are subsampled and the treatment F-ratio in an analysis of variance (ANOVA) table is formed with respect to the residual mean square rather than with respect to the among unit mean square. The F-ratio relative to the within unit mean square is vulnerable to the confounding of treatment and unit effects, especially when unit number is small (e.g. four tank units, two tanks treated, two not treated, several subsamples per tank). The problem is eliminated by forming the F-ratio relative to the among unit mean square in the ANOVA table (tank MS in the example above). Replication[edit] Hypothesis testing[edit] Statistical tests (e.g. t-test and the related ANOVA family of tests) rely on appropriate replication to estimate statistical confidence.