Physics posts
- March 12, 2010
- 12:00 PM
- 48 views
The (empirical) rule of 8%
by Pablo Artal in Optics confidential
Some advice on how to deal with students and postdocs...... Read more »
Perez, G., Archer, S., & Artal, P. (2009) Optical Characterization of Bangerter Foils. Investigative Ophthalmology , 51(1), 609-613. DOI: 10.1167/iovs.09-3726
- March 6, 2010
- 05:33 PM
- 50 views
From Conducting Polimers to First Organic Superconductors
by Olexandr Isayev in isayev.info
This week, I returned from the historic 50th Sanibel Symposium. Over 350 chemists and physicists gathered together to celebrate half-centennial success of quantum and computational chemistry. One lecture that caught my attention was a plenary talk “Conducting Polymers: a saga of more than 50 years” by professor Jean-Marie Andre. Professor Andre emphasized a role [...]... Read more »
Pople, J., & Walmsley, S. (1962) Bond alternation defects in long polyene molecules. Molecular Physics, 5(1), 15-20. DOI: 10.1080/00268976200100021
Su, W., Schrieffer, J., & Heeger, A. (1980) Soliton excitations in polyacetylene. Physical Review B, 22(4), 2099-2111. DOI: 10.1103/PhysRevB.22.2099
Mitsuhashi, R., Suzuki, Y., Yamanari, Y., Mitamura, H., Kambe, T., Ikeda, N., Okamoto, H., Fujiwara, A., Yamaji, M., Kawasaki, N.... (2010) Superconductivity in alkali-metal-doped picene. Nature, 464(7285), 76-79. DOI: 10.1038/nature08859
- March 5, 2010
- 08:18 PM
- 48 views
Shrinky Dinks Thermoplastics: Toying With Cutting Edge Research
by Robert Deyes in Promega Connections
There it sat- a wedge-shaped gift under the Christmas tree, distinct from all the regular oblongs and cubes that had been carefully wrapped by my wife for both the children. As Christmas drew nearer, there was clearly a buzz over what the contents of the mysterious wedge container might be. The outer label which simply [...]... Read more »
Grimes A, Breslauer DN, Long M, Pegan J, Lee LP, & Khine M. (2008) Shrinky-Dink microfluidics: rapid generation of deep and rounded patterns. Lab on a chip, 8(1), 170-2. PMID: 18094775
- March 4, 2010
- 03:36 PM
- 57 views
Rolling out the (optical) carpet: the Talbot effect
by gg in Skulls in the Stars
One of the wonderful things about having a career in science is that a deeper understanding of the science leads to a greater appreciation of its beauty. In physics, this usually requires a nontrivial amount of mathematics, but there are some phenomena that are self-evidently beautiful; unfortunately, many of these are also not very well [...]... Read more »
H.F. Talbot. (1836) Facts relating to optical science. No. IV. Philosophical Magazine, 401-407. info:/
- February 28, 2010
- 04:36 PM
- 63 views
The teapot effect, end of
by aimeew in misc.ience
Fluid dynamicists have figured out how to fight the dreaded teapot dribble, using a mixture of materials and teapot mouth structure.... Read more »
Cyril Duez, Christophe Ybert, Christophe Clanet, and Lyderic Bocquet. (2010) Wetting Controls Separation of Inertial Flows from Solid Surfaces. Physical Review Letters. info:/10.1103/PhysRevLett.104.084503
- February 27, 2010
- 02:34 PM
- 51 views
Piezoelectric fabric… again
by Lars Fischer in EuCheMS 2010 Blog
The latest edition of Nano Letters has yet another paper about some sort of piezoelectric fabric that generates electricity when deformed. In Theory, you could wear pants made from this stuff and power, say, your watch just by walking around. Admittedly this isn’t exactly novel. We heard about it already in 2003 (pdf), 2007 and [...]... Read more »
Qi, Y., Jafferis, N., Lyons, K., Lee, C., Ahmad, H., & McAlpine, M. (2010) Piezoelectric Ribbons Printed onto Rubber for Flexible Energy Conversion. Nano Letters, 10(2), 524-528. DOI: 10.1021/nl903377u
- February 18, 2010
- 07:00 AM
- 87 views
Chromatic aberration of the eye: to correct or not to correct?
by Pablo Artal in Optics confidential
The human eye suffers of a very large chromatic aberration. This means that when a red object is in focus, a blue one at the same distance will be clearly out of focus. Why we are not yet routinely correcting this defect to improve vision? You will find here some new experiments, results and explanations...... Read more »
Artal, P., Manzanera, S., Piers, P., & Weeber, H. (2010) Visual effect of the combined correction of spherical and longitudinal chromatic aberrations. Optics Express, 18(2), 1637. DOI: 10.1364/OE.18.001637
- February 17, 2010
- 07:10 PM
- 72 views
Pop Goes the Pulsar
by Brian Koberlein in Upon Reflection
Note: This entry is a bit different from most of my posts. It is more mathematical, and uses MathML extensively to display equations. If you see gibberish instead of equations, then your browser isn't capable of viewing them. If you...... Read more »
HEWISH, A., BELL, S., PILKINGTON, J., SCOTT, P., & COLLINS, R. (1968) Observation of a Rapidly Pulsating Radio Source. Nature, 217(5130), 709-713. DOI: 10.1038/217709a0
- February 10, 2010
- 11:22 PM
- 98 views
The Cosmos isn't strange, people are strange
by The Astronomist in The Astronomist.
The cosmos isn't strange, people are strange. The universe on the largest of scales is actually simple compared to the complexities of the human mind or even the weather. In a statistical sense all current observations indicate that universe is homogeneous and isotropic everywhere. The best evidence for this statement is the cosmic microwave background (CMB) radiation which is light from the big bang that has traveled unimpeded through the universe since recombination. A simp........ Read more »
C. L. Bennett, R. S. Hill, G. Hinshaw, D. Larson, K. M. Smith, J. Dunkley, B. Gold, M. Halpern, N. Jarosik, A. Kogut.... (2010) Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Are There Cosmic Microwave Background Anomalies?. ApJ. arXiv: 1001.4758v1
- February 9, 2010
- 07:15 PM
- 129 views
Quantum Psychology?
by Michael Bishop in Permutations
Let me be frank; I think “The conjunction fallacy and interference effects” (ungated version) is a horrible misuse of math and indicates an embarrassing failure of peer review.
The author, Riccardo Franco, introduces a parameter that does doesn’t have any foundation in the phenomena it is trying to explain, nor is it shown to aid in [...]... Read more »
Franco, R. (2009) The conjunction fallacy and interference effects. Journal of Mathematical Psychology, 53(5), 415-422. DOI: 10.1016/j.jmp.2009.02.002
- February 9, 2010
- 02:40 PM
- 94 views
Mobile Phones' Impact on Health
by amiya in Physiology physics woven fine
Mobile phones have drastically transformed our lives. Also known as cellular phones or cell phones, these gadgets not only incorporate a phone, as the name suggests, but also a lot of other technologically advanced features. They include a camera, a sound recorder cum music system, a Bluetooth device and many more depending on the model and the maker of the phone. They are called mobile phones since they can be used while on the move.A mobile phone maintains a two way (transmit and receive) comm........ Read more »
Gary W. Arendash, Juan Sanchez-Ramos, Takashi Mori, Malgorzata Mamcar, Xiaoyang Lin, Melissa Runfeldt, Li Wang, Guixin Zhang, Vasyl Sava, Jun Tan.... (2010) Electromagnetic Field Treatment Protects Against and Reverses Cognitive Impairment in Alzheimer's Disease Mice . Journal of Alzheimer's Disease, 191-210. info:/
- February 4, 2010
- 03:36 AM
- 113 views
The end of gravity as we know it?
by sarah in SarahAskew
When a physicist is on the front page of a newspaper, you know the story is either really bad, or really good. Just before Christmas, the Dutch paper De Volkskrant ran a big story on theoretical physicist Erik Verlinde, who has been making waves with his new theory for the origin of gravity. Since the [...]... Read more »
Erik P. Verlinde. (2010) On the Origin of Gravity and the Laws of Newton. arxiv. arXiv: 1001.0785v1
- February 3, 2010
- 10:55 AM
- 116 views
Accelerated Twins: The Answer
by Chad Orzel in Uncertain Principles
Yesterday's post on a variation of the "Twin Paradox" with both twins accelerating was very successful-- 337 people voted in the first poll question, as of a little before 9am, and the comments to the original post are full of lively discussion. That's awesome.
I wish I could take credit for it, but the problem posed is not original to me. It comes from a 1989 paper in the American Journal of Physics, which also includes the following illustration setting up the situation:
The article contai........ Read more »
Boughn, S. (1989) The case of the identically accelerated twins. American Journal of Physics, 57(9), 791. DOI: 10.1119/1.15894
Desloge, E. (1991) Comment on ‘‘The case of the identically accelerated twins,’’ by S. P. Boughn [Am. J. Phys. 57, 791–793 (1989)]. American Journal of Physics, 59(3), 280. DOI: 10.1119/1.16580
- February 3, 2010
- 07:45 AM
- 103 views
The Attraction of Curves
by Brian Koberlein in Upon Reflection
Figure 1: Newton's gravity predicts an elliptical orbit for Mercury (similar to the red path). Mercury's orbit actually shifts over time (similar to the path in blue). Mercury's motion agrees with Einstein's model of gravity. (Source: Wikipedia) Last time I...... Read more »
Dyson, F., Eddington, A., & Davidson, C. (1920) A Determination of the Deflection of Light by the Sun's Gravitational Field, from Observations Made at the Total Eclipse of May 29, 1919. Philosophical Transactions of the Royal Society of London. Series A, Containing Papers of a Mathematical or Physical Character (1896-1934), 220(1), 291-333. DOI: 10.1098/rsta.1920.0009
- February 2, 2010
- 03:00 AM
- 89 views
What Enables Termites to Fly in Rain?
by Michael Long in Phased
Gregory Watson (James Cook University, Australia) and coworkers have discovered small-scale architecture on termite wings that imparts remarkable water-repelling properties, while adding only minimal weight to the wings, enabling a species of weak fliers to readily fly in rain. This news feature was written on February 2, 2010.... Read more »
Watson, G. S., Cribb, B. W., & Watson, J. A. (2010) How Micro/Nanoarchitecture Facilitates Anti-Wetting: An Elegant Hierarchical Design on the Termite Wing. ACS Nano, 4(1), 129-136. DOI: 10.1021/nn900869b
- January 31, 2010
- 12:31 AM
- 92 views
Magnetic fields in gamma-ray burst jets
by Charles Daney in Science and Reason
Gamma-ray bursts (GRBs) are the most dramatic short-lived violent events observed in the universe. They are often described as releasing a quantity of energy, in less than a minute, that is at least as much as a star like the Sun releases in its entire 10 billion year lifetime. Since the first detection of a gamma-ray burst in 1967, the central question has been to determine the nature of the process or processes that can release so much energy so quickly.We've discussed gamma-ray burst several ........ Read more »
Steele, I., Mundell, C., Smith, R., Kobayashi, S., & Guidorzi, C. (2009) Ten per cent polarized optical emission from GRB 090102. Nature, 462(7274), 767-769. DOI: 10.1038/nature08590
- January 29, 2010
- 04:45 AM
- 126 views
The Entropy of the Universe
by Alexander in The Astronomist.
First, what is entropy? The entropy of a system can be defined as proportional to (the natural log of) the number of microstates corresponding to the observed system macrostate. In this post I discuss a paper for anyone was wondering what the entropy of the observable Universe is.... Read more »
Chas A. Egan, & Charles H. Lineweaver. (2010) A Larger Estimate of the Entropy of the Universe. ApJ. arXiv: 0909.3983v3
- January 26, 2010
- 08:59 AM
- 140 views
Migratory Monarch Butterflies See Earth's GeoMagnetic Field
by GrrlScientist in Living the Scientific Life (Scientist, Interrupted)
tags: evolutionary biology, behavioral ecology, biochemistry, biophysics, magnetoreception, photochemical mechanism, cryptochromes, geomagnetic fields, butterflies, Monarch Butterfly, Danaus plexippus, birds, migration, Cryptochrome, bpr3.org/?p=52,peer-reviewed research, peer-reviewed paper
Every autumn, millions of monarch butterflies, Danaus plexippus, each weighing less than one gram (one US penny weighs 2.5 grams), migrate nearly 4000 kilometers (3000 miles) between their summer bree........ Read more »
Gegear, R., Foley, L., Casselman, A., & Reppert, S. (2010) Animal cryptochromes mediate magnetoreception by an unconventional photochemical mechanism. . Nature. DOI: 10.1038/nature08719
- January 25, 2010
- 11:14 AM
- 133 views
Single-Photon Cooling: Making Maxwell's Demon
by Chad Orzel in Uncertain Principles
As mentioned previously, I've been reading Sean Carroll's Wheel arrow of time book, which necessarily includes a good bit of discussion of "Maxwell's Demon," a thought experiment famously proposed by James Clerk Maxwell as something that would allow you to cool a gas without obviously increasing entropy. The "demon" mans a trapdoor between a sample of gas and an initially empty space, and allows only slow-moving gas atoms to pass through. After some time, the empty volume is filled with a gas at........ Read more »
Travis Bannerman, S., Price, G., Viering, K., & Raizen, M. (2009) Single-photon cooling at the limit of trap dynamics: Maxwell's demon near maximum efficiency. New Journal of Physics, 11(6), 63044. DOI: 10.1088/1367-2630/11/6/063044
Raizen, M. (2009) Comprehensive Control of Atomic Motion. Science, 324(5933), 1403-1406. DOI: 10.1126/science.1171506
- January 23, 2010
- 12:44 PM
- 134 views
Can science be artistic?
by nuclear.kelly in Miss Atomic Bomb
In light of the lack of effective communication between scientists (and science generally) and the public, I posed a challenge to the graduate students in my department: write a story about your research. It seemed a simple task, but there was one catch - the story had to be a fictional tale about their actual work.Can science be artistic? Is it only a chosen few who can turn science into the kind of thing that people on the street (or in the pub) find interesting; people like Carl Sagan, Brian ........ Read more »
Chipps, K., Blackmon, J., Chae, K., Moazen, B., Pittman, S., Greife, U., Hatarik, R., Peters, W., Kozub, R., Shriner, J.... (2009) The ^{17}F(p,γ)^{18}Ne resonant cross section. Physical Review C, 80(6). DOI: 10.1103/PhysRevC.80.065810
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