1,662 research outputs found
Reconstructing phylogeny from RNA secondary structure via simulated evolution
DNA sequences of genes encoding functional RNA molecules (e.g., ribosomal RNAs) are commonly used in phylogenetics (i.e. to infer evolutionary history). Trees derived from ribosomal RNA (rRNA) sequences, however, are inconsistent with other molecular data in investigations of deep branches in the tree of life. Since much of te functional constraints on the gene products (i.e. RNA molecules) relate to three-dimensional structure, rather than their actual sequences, accumulated mutations in the gene sequences may obscure phylogenetic signal over very large evolutionary time-scales. Variation in structure, however, may be suitable for phylogenetic inference even under extreme sequence divergence. To evaluate qualitatively the manner in which structural evolution relates to sequence change, we simulated the evolution of RNA sequences under various constraints on structural change
Was Einstein Right? Testing Relativity at the Centenary
We review the experimental evidence for Einstein's special and general
relativity. A variety of high precision null experiments verify the weak
equivalence principle and local Lorentz invariance, while gravitational
redshift and other clock experiments support local position invariance.
Together these results confirm the Einstein Equivalence Principle which
underlies the concept that gravitation is synonymous with spacetime geometry,
and must be described by a metric theory. Solar system experiments that test
the weak-field, post-Newtonian limit of metric theories strongly favor general
relativity. The Binary Pulsar provides tests of gravitational-wave damping and
of strong-field general relativity. Recently discovered binary pulsar systems
may provide additional tests. Future and ongoing experiments, such as the
Gravity Probe B Gyroscope Experiment, satellite tests of the Equivalence
principle, and tests of gravity at short distance to look for extra spatial
dimensions could constrain extensions of general relativity. Laser
interferometric gravitational-wave observatories on Earth and in space may
provide new tests of gravitational theory via detailed measurements of the
properties of gravitational waves.Comment: 21 pages, 3 figures, to be published in "100 Years of Relativity:
Spacetime Structure - Einstein and Beyond", ed. Abhay Ashtekar (World
Scientific, Singapore
Evolutionary biology and computational grids
The global high performance computing community has seen two overarching changes in the past five years. One of these changes was the consolidation toward SMP clusters as the predominant HPC system architecture. The other change was the emergence of computing grids as an important architecture in high performance computing. Several major national and international projects are now underway to develop grid technologies. Computational grids will increase the resources available to the most advanced computational scientists and encourage the use of advanced techniques by researchers who have not traditionally employed such technologies. In the latter camp are bioinformaticists in general and evolutionary biologists in particular, although this situation is changing rapidly.This work was greatly facilitated by IBM Shared University Research grants to Indiana University in 1998 and 1999
Concert recording 2014-04-06
[Track 01]. Rigaudon de Dardanus / Jean-Philippe Rameau ; arranged by Corroyez -- [Track 02]. What shall we do with a drunken sailor? / Sea Chantey ; arranged by Worley -- [Track 03]. Quartette / Caryl Florio -- [Track 04]. Diversions in denim. Excursion ; [Track 05]. Idlewood ; [Track 06]. Gallumphery ; [Track 07]. Lornsome ; [Track 08]. Shindig / Carl Anton Wirth -- [Track 09]. Finale from Brandenburg concerto no. 3 / J.S. Bach ; arranged by Laycock -- [Track 10]. Portals / Carl Anton Wirth -- [Track 11]. Moderato ; [Track 12]. Allegro / Erland von Koch
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