169,557 research outputs found
Metabolic analyzer
An apparatus is described for the measurement of metabolic rate and breathing dynamics in which inhaled and exhaled breath are sensed by sealed, piston-displacement type spirometers. These spirometers electrically measure the volume of inhaled and exhaled breath. A mass spectrometer analyzes simultaneously for oxygen, carbon dioxide, nitrogen and water vapor. Computation circuits are responsive to the outputs of the spirometers, mass spectrometer, temperature, pressure and timing signals and compute oxygen consumption, carbon dioxide production, minute volume and respiratory exchange ratio. A selective indicator provides for read-out of these data at predetermined cyclic intervals
Holographic local quench and effective complexity
We study the evolution of holographic complexity of pure and mixed states in
-dimensional conformal field theory following a local quench using both
the "complexity equals volume" (CV) and the "complexity equals action" (CA)
conjectures. We compare the complexity evolution to the evolution of
entanglement entropy and entanglement density, discuss the Lloyd computational
bound and demonstrate its saturation in certain regimes. We argue that the
conjectured holographic complexities exhibit some non-trivial features
indicating that they capture important properties of what is expected to be
effective (or physical) complexity.Comment: 33 pages, 19 figures; v2: typos corrected; 35 pages, references
added, new appendix. Version to match published in JHE
One machine, one minute, three billion tetrahedra
This paper presents a new scalable parallelization scheme to generate the 3D
Delaunay triangulation of a given set of points. Our first contribution is an
efficient serial implementation of the incremental Delaunay insertion
algorithm. A simple dedicated data structure, an efficient sorting of the
points and the optimization of the insertion algorithm have permitted to
accelerate reference implementations by a factor three. Our second contribution
is a multi-threaded version of the Delaunay kernel that is able to concurrently
insert vertices. Moore curve coordinates are used to partition the point set,
avoiding heavy synchronization overheads. Conflicts are managed by modifying
the partitions with a simple rescaling of the space-filling curve. The
performances of our implementation have been measured on three different
processors, an Intel core-i7, an Intel Xeon Phi and an AMD EPYC, on which we
have been able to compute 3 billion tetrahedra in 53 seconds. This corresponds
to a generation rate of over 55 million tetrahedra per second. We finally show
how this very efficient parallel Delaunay triangulation can be integrated in a
Delaunay refinement mesh generator which takes as input the triangulated
surface boundary of the volume to mesh
Physics of computation and light sheet concept in the measurement of (4+n)-dimensional spacetime geometry
We analyze the limits that quantum mechanics imposes on the accuracy to which
-dimensional spacetime geometry can be measured. Using physics of
computation and light sheet concept we derive explicit expressions for quantum
fluctuations and explore their cumulative effects for various spacetime foam
models.Comment: 5 page
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