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The Orbitron

The Orbitron
a gallery of atomic orbitals and molecular orbitals on the WWW Images representing atomic orbitals and molecular orbitalsAnimated plots of wave functionsAnimated plots of electron density"Dot-density" plots of electron densityPlots of radial distribution functions A note Please note: our server is very fast but The Orbitron contains files that are quite large, and so may take some time to download if your internet connection is slow. Adapted from Encarta World English Dictionary: -tron suffix. a device for manipulating atoms or subatomic particles, accelerator. Orbital /áwrbit'l/ noun. You can now buy the Orbitron atomic orbitals poster. Related:  ²newdocs

Symmetry @ Otterbein Electron degeneracy pressure When electrons are squeezed too close together, the exclusion principle requires them to have different energy levels. To add another electron to a given volume requires raising an electron's energy level to make room, and this requirement for energy to compress the material manifests as a pressure. Electron degeneracy pressure in a material can be computed as[4] where is the reduced Planck constant, is the mass of the electron, and is the free electron density (the number of free electrons per unit volume). This is derived from the energy of each electron with wave number , having , and every possible momentum state of an electron within this volume up to the Fermi energy being occupied. This degeneracy pressure is omnipresent and is in addition to the normal gas pressure . ) is high enough, and the temperature low enough, that the sum is dominated by the degeneracy pressure. See also[edit] References[edit] Jump up ^ Dyson, F.

Unsociable methane comes in from the cold - physics-math - 13 May 2011 An abundant but stand-offish carbon-based molecule has been coaxed into playing nice. Chemists have devised a way to persuade methane to react with other molecules under gentle conditions, making it vastly more useful as a building block for synthesising more complex organic chemicals. Methane molecules are composed of a single carbon atom connected to four hydrogens. This means methane is the simplest of all the hydrocarbons that contain only simple carbon-hydrogen (C-H) bonds. To form a bond with another molecule or atom, at least one of these C-H bonds must break. But these bonds are stronger in methane than in any other similar molecule. Methane is therefore rather reluctant to react – which is why vast pockets of pure methane or natural gas exist in the Earth, which are siphoned for use as fuel. The downside of this lack of reactivity is that it makes methane an inconvenient raw material for the manufacture of drugs, plastics and innumerable other carbon-based compounds. Fermionic field In quantum field theory, a fermionic field is a quantum field whose quanta are fermions; that is, they obey Fermi–Dirac statistics. Fermionic fields obey canonical anticommutation relations rather than the canonical commutation relations of bosonic fields. Basic properties[edit] Free (non-interacting) fermionic fields obey canonical anticommutation relations, i.e., involve the anticommutators {a,b} = ab + ba rather than the commutators [a,b] = ab − ba of bosonic or standard quantum mechanics. It is these anticommutation relations that imply Fermi–Dirac statistics for the field quanta. Dirac fields[edit] The prominent example of a spin-1/2 fermion field is the Dirac field (named after Paul Dirac), and denoted by ψ(x). where γμ are gamma matrices and m is the mass. and . The a and b labels are spinor indices and the s indices represent spin labels and so for the electron, a spin 1/2 particle, s = +1/2 or s=−1/2. are operators. obey the anticommutation relations: . clear. See also[edit]

What is Synthetic Biology? « A Tempting Science Many languages have words and phrases, called contranyms, that have two nearly opposite meanings. For example, a “citation” from Harvard University is good, but a “citation” from the Harvard University police is bad. If you run “fast”, you are moving at great speed; if you hold “fast”, you are not moving at all. “Synthetic biology” is a contranym. In a version popular today in some engineering communities, “synthetic biology” seeks to use natural parts of biological systems (like DNA fragments or protein “biobricks”) to create assemblies that do things that are not done by natural biology (such as digital computation or specialty chemical manufacture). Among chemists, “synthetic biology” means the opposite. Waclaw Szybalski had yet a different meaning in mind when he coined the term “synthetic biology” in 1974 [2]. Szybalski had the experience of chemistry in mind when he coined the term. By 1974, “synthetic organic chemistry” had already encroached deep within biological territory.

JSDraw JSDraw brings chemistry capabilities to your web pages. With this javascript libary you can display and draw chemical structures in web pages, which works cross browser, including IE, Firefox, Safari, Opera and Chrome, crose platform, including Window, Mac, Linux, and even iPhone, Android and other mobile devices. Example 2 (Editor, using molfile): Example 3 (Editor, using JSDraw compatible html): Example 4 (SDF Viewer): David Tong -- Cambridge Lecture Notes on Quantum Field Theory These lecture notes are based on an introductory course on quantum field theory, aimed at Part III (i.e. masters level) students. The full set of lecture notes can be downloaded here, together with videos of the course when it was repeated at the Perimeter Institute. Individual sections can be downloaded below. Last updated October 2012. PostScript PDF Videos 0. Philip Tanedo, who took this course long ago, has put together a useful literature review of quantum field theory textbooks. The late Sidney Coleman taught the quantum field theory course at Harvard for many years, influencing a generation of physicists in the way they view and teach QFT. Part 1 Part 2 These notes were subsequently latexed and posted on the arXiv. Another, older legendary QFT course was given in 1951 by Freeman Dyson.

BaraminologyClassification of Created Organisms Copyright © 2000 by Creation Research Society. All rights reserved. Wayne Frair, Ph.D CRSQ Vol 37 No 2 pp82-91 September 2000 Invited Paper Abstract For decades creationists have been using the word “kind,” “type,” or “group” for their envisioned categories of genetically unrelated organisms including all those formed by the Creator during Creation Week. Introduction Basic human attributes include classification and identification. Interestingly, the Bible includes an account of God’s bringing to Adam all the terrestrial animals and birds (Genesis 2:19) so that Adam could observe and name them. In addition, Adam would learn something about God—the Designer. Taxonomy and Systematics Pondering these matters makes it easier for us to realize the basic importance of classification in biological studies of extinct and extant forms of life. However, there are different approaches used by scientists for studying patterns of life and for classification. Discontinuity Systematics and Baraminology

Computational complexity theory Computational complexity theory is a branch of the theory of computation in theoretical computer science and mathematics that focuses on classifying computational problems according to their inherent difficulty, and relating those classes to each other. A computational problem is understood to be a task that is in principle amenable to being solved by a computer, which is equivalent to stating that the problem may be solved by mechanical application of mathematical steps, such as an algorithm. A problem is regarded as inherently difficult if its solution requires significant resources, whatever the algorithm used. Closely related fields in theoretical computer science are analysis of algorithms and computability theory. Computational problems[edit] A traveling salesman tour through Germany’s 15 largest cities. Problem instances[edit] A computational problem can be viewed as an infinite collection of instances together with a solution for every instance. Representing problem instances[edit]

Game of Life News: Oblique Life spaceship created Andrew J. Wade has recently built a self-replicating configuration in Life. It consists of two stable configurations equipped with Chapman-Greene construction arms, and a volley of gliders circulating between them. The announcement was made on this forum thread . The spaceship propagates at the impressively slow speed of (5120,1024)c/33699586. Undoubtedly, this creation will lead to an avalanche of discoveries in Life. It differs from the Standard Architecture in a variety of ways. The configuration uses three Chapman-Greene construction arms at each end of the tape: two perpendicular arms for construction, and a third arm for destruction. This is the thirteenth explicitly constructed spaceship velocity in Life, although it facilitates an infinite number of related velocities.

This Can't Be Happening : Krulwich Wonders... OK, if you've got nothing else to do for one minute, let me mess with your head. Below, you will see two circles composed of parallelograms. There's a dot in the middle of the image. Focus on the dot. Move your head in, then move it out. B. Weird, no? The circles seem to rotate. (Of course, they don't really rotate; if you focus on a single parallelogram, you can move your head in and out all day and that sucker won't move at all.) Something curious is going on. So I went to see an eye doctor (technically, he's a "visual science" professor, Ben Backus, at the State University of New York's College of Optometry) who agreed to explain to me why the circles seem to move. Yes, he said, what you are seeing is a lie ("illusion" is the polite word) but don't blame your lying eyes. Tricking Your Brain "We don't see motion directly," he told me. Here's how. There are cells in your brain that specialize in motion detection. Put the portholes together, you can see the world. You can do this yourself.

Telomerase Tribolium castaneum telomerase catalytic subunit, TERT, bound to putative RNA template and telomeric DNA (PDB 3KYL) The existence of a compensatory mechanism for telomere shortening was first predicted by Soviet or Russian biologist Alexey Olovnikov in 1973,[2] who also suggested the telomere hypothesis of aging and the telomere's connections to cancer. Telomerase was discovered by Carol W. Greider and Elizabeth Blackburn in 1984 in the ciliate Tetrahymena.[3] Together with Jack W. The role of telomeres and telomerase in cell aging and cancer was established by scientists at biotechnology company Geron with the cloning of the RNA and catalytic components of human telomerase [5] and the development of a PCR- based assay for telomerase activity called the TRAP assay allowing for a survey of telomerase activity in multiple types of cancer.[6] Structure[edit] TERT is a reverse transcriptase, which is a class of enzyme that creates single-stranded DNA using single-stranded RNA as a template.

Go Easy on Yourself, a New Wave of Research Urges Stuart Bradford Do you treat yourself as well as you treat your friends and family? That simple question is the basis for a burgeoning new area of psychological research called self-compassion — how kindly people view themselves. People who find it easy to be supportive and understanding to others, it turns out, often score surprisingly low on self-compassion tests, berating themselves for perceived failures like being overweight or not exercising. The research suggests that giving ourselves a break and accepting our imperfections may be the first step toward better health. People who score high on tests of self-compassion have less depression and anxiety, and tend to be happier and more optimistic. This idea does seem at odds with the advice dispensed by many doctors and self-help books, which suggest that willpower and self-discipline are the keys to better health. Imagine your reaction to a child struggling in school or eating too much junk food. Dr. For those low on the scale, Dr.