Month: December 2008
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Modelling the spread of HIV
Modelling the spread of HIV is a difficult business for many reasons: many people are unaware that they are infected, HIV can take a very long time to manifest itself within the body, and researchers are still unsure to what extent different population groups are involved in its transmission. So it’s remarkable that Shan Mei…
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Calculating the probability of immortality
How likely is it that a given object will survive forever? With many groups predicting that human immortality is just around the corner, you could say we all have a vested interest in the answer. A t first glance, the odds are not good. As David Eubanks of Coker College in South Carolina puts it:…
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Secrets ‘n’ lies
The best of the rest from the physics arXiv this week: Grain Size Dependence of Barchan Dune Dynamics On the History of Geometrization of Space-time: From Minkowski to Finsler Geometry Graviton, Ghost and Instanton Condensation on Horizon Scale of the Universe. Dark Energy as a Macroscopic Effect of Quantum Gravity The Upper Atmosphere of HD17156b…
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Quantum direct communication: secrecy without key distribution
An interesting development in the world of quantum encryption. In the last couple of years, we’ve seen a number of quantum key distribution systems being set up that boast close-to-perfect security (although they’re not as secure as the marketing might imply). These systems rely on two-part security. The first is the quantum part which reveals…
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Levitating gas pipelines
Great to see one of the arXiv’s most creative minds posting again today. Alexander Bolonkin–he of “In Outer Space without a Space Suit?” and “Floating Cities, Islands and States” fame–is back with another startling idea. Methane is significantly lighter than air and so could be used to levitate the pipes it flows through. These aerial…
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Loop quantum cosmology: a brief overview
Abhay Ashtekar, a physicist at the Pennsylvania State University is one of the founders of loop quantum cosmology and also a part-time populariser of science. Today, he uses both of these attributes to produce a fascinating overview of loop quantum cosmology that non-specialists will find enlightening. A recommended read. Ref: arxiv.org/abs/0812.0177: Loop Quantum Cosmology: An…
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Quantum test found for mathematical undecidability
It was the physicist Eugene Wigner who discussed the “unreasonable effectiveness of mathematics” in a now famous paper that examined the profound link between mathematics and physics. Today, Anton Zeilinger and pals at the University of Vienna in Austria reveal this link at its deepest. Their experiment involves the issue of mathematical decidability. First, some…
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How ribosomal traffic cops keep bacteria alive
Ribosomes are the genetic Turing machines that translate nucleic acid into protein. And fast growing bacteria need plenty of them. E coli bacteria, for example, contain some 73000 ribosomes per cell. Given that E coli populations double every 20 minutes, new ribosomes have to be created at a fantastic rate. The process requires ribosomal RNA…