8,265 research outputs found
SET-E: The Search for Extraterrestrial Environmentalism
There is currently no evidence for life on any known exoplanet. Here, we
propose a form of "galactic anthropology" to detect not only the existence of
life on transiting exoplanets, but also the existence of environmentalism
movements. By observing the planet's atmosphere over long time baselines, the
destruction and recovery of a hole in an exoplanet's ozone layer may be
observable. While not readily detectable for any one system with JWST, by
binning together observations of hundreds of systems we can finally determine
the occurrence rate of environmental movements on Earthlike planets in the
galaxy, a number we term eta-Green-Earth.Comment: 4 pages, 2 figures, Comments Welcom
Embeddings of 3-manifolds in S^4 from the point of view of the 11-tetrahedron census
This is a collection of notes on embedding problems for 3-manifolds. The main
question explored is `which 3-manifolds embed smoothly in the 4-sphere?' The
terrain of exploration is the Burton/Martelli/Matveev/Petronio census of
triangulated prime closed 3-manifolds built from 11 or less tetrahedra. There
are 13766 manifolds in the census, of which 13400 are orientable. Of the 13400
orientable manifolds, only 149 of them have hyperbolic torsion linking forms
and are thus candidates for embedability in the 4-sphere. The majority of this
paper is devoted to the embedding problem for these 149 manifolds. At present
41 are known to embed. Among the remaining manifolds, embeddings into homotopy
4-spheres are constructed for 4. 67 manifolds are known to not embed in the
4-sphere. This leaves 37 unresolved cases, of which only 3 are geometric
manifolds i.e. having a trivial JSJ-decomposition.Comment: 58 pages, 80+ figures. V6: Included references to libraries valid in
Regina 5.0+. Incorporated changes suggested by Ahmed Issa, following from his
techniques developed with McCoy. Included a few recent references. To appear
in Experimental Mathematic
Following the Money 2012: How the 50 States Rate in Providing Online Access to Government Spending Data
Assesses states' progress in offering comprehensive, one-stop access to searchable and downloadable databases of government spending via transparency 2.0 Web sites, including searchability, user-friendliness, breadth of data, and features such as mapping
3D Imaging of Gems and Minerals by Multiphoton Microscopy
Many optical approaches have been used to examine the composition and
structure of gemstones, both recently and throughout history. The nonlinear
optical behavior of different gemstones has not been investigated, and the
higher order terms to the refractive index represent an unused tool for
qualifying and examining a stone. We have used a multiphoton microscope to
examine the nonlinear optical properties of 36 different gemstones and
demonstrate that it is a useful tool for imaging them three-dimensionally up to
the millimeter scale below the sample surface. The polarization dependence of
second harmonic generation signals was used to examine the crystal orientations
inside the minerals.Comment: 9 pages, five figure
Spin foam models with finite groups
Spin foam models, loop quantum gravity and group field theory are discussed
as quantum gravity candidate theories and usually involve a continuous Lie
group. We advocate here to consider quantum gravity inspired models with finite
groups, firstly as a test bed for the full theory and secondly as a class of
new lattice theories possibly featuring an analogue diffeomorphism symmetry. To
make these notes accessible to readers outside the quantum gravity community we
provide an introduction to some essential concepts in the loop quantum gravity,
spin foam and group field theory approach and point out the many connections to
lattice field theory and condensed matter systems.Comment: 47 pages, 6 figure
Design and prototype of an external quality assurance program for urine bicarbonate
This dissertation validates a Beckman-Coulter DxC(R) assay for total bicarbonate in urine and then proceeds to design, prototype and cost an inter-laboratory comparison (ILC) program for the above urine bicarbonate based on the validation. Furthermore, this work serves as a case study for how to establish proficiency testing - and thereby achieve accreditation - for tests without external quality assurance because of analyte instability
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