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Swirling around the planet’s equator, the rings of Saturn are a dead giveaway that the planet is spinning at a tilt. The belted giant rotates at a 26.7-degree angle relative to the plane in which it o...
MIT chemists have devised a new chemical reaction that allows them to synthesize a phosphorus-containing ring, using a catalyst to add phosphorus to simple organic compounds called alkenes.
By reading between the lines of tree rings, U.S. National Science Foundation-funded researchers at the University of Arizona reconstructed what happened in Alaska the year the Laki Volc...
In previous papers, University of Pennsylvania physicists investigated the “coffee ring effect,” the ring-shaped stain of particles left after drops of coffee evaporate. In one paper, they learned how...
Rice University astronomers and their colleagues have for the first time mapped gases in three dark rings around a distant star. The rings mark spaces where planets are thought to have formed from dus...
Most basic physics textbooks describe laser light in fairly simple terms: a beam travels directly from one point to another and, unless it strikes a mirror or other reflective surface, will continue t...
Some of the world’s most important discoveries – penicillin, vulcanized rubber and Velcro, to name a few – were made by accident. In fact, it’s been said that upward of half of all scientific discover...
We present results from a large suite of simulations of Saturn’s dense A and B rings using a new model of particle sticking in local simulations (Perrine, R.P., Richardson, D.C., Scheeres, D.J. [2011]...
We present a numerical method that incorporates particle sticking in simulations using the N-body code pkdgrav to study motions in a local rotating frame, such as a patch of a planetary ring. Particle...
We have developed a semianalytic method of parameterizing N-body simulations of self-gravity wakes in Saturn’s rings, describing their photometric properties by means of only six numbers: three optica...
Let G be a finite group. We classify G-equivariant flow equivalence of nontrivial irreducible shifts of finite type interms of (i) elementary equivalence of matrices over ZG and (ii) the conjugacy cla...
Some trees from tropical areas lack visually detectable and consistent annual growth rings. As such, we have measured the radial variation of cellulose oxygen isotopes in trees that grow in seasonall...
An intriguing observation of photosynthetic light-harvesting systems is theN-fold symmetry of light-harvesting complex 2 (LH2) of purple bacteria. We calculate the optimal rotational configuration of ...
Using nonstandard analysis we define a topology on the ring of germs of functions: $(mathbb R^n,0)\rightarrow(mathbb R,0)$. We prove that this topology is absolutely convex, Hausdorff, that convergent...
We construct a number of different examples of non-Noetherian graded rings that are injective as modules over themselves (or have some related but weaker properties). We discuss how these are related ...

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