4,033 research outputs found
Pattern matching and pattern discovery algorithms for protein topologies
We describe algorithms for pattern matching and pattern
learning in TOPS diagrams (formal descriptions of protein topologies).
These problems can be reduced to checking for subgraph isomorphism
and finding maximal common subgraphs in a restricted class of ordered
graphs. We have developed a subgraph isomorphism algorithm for
ordered graphs, which performs well on the given set of data. The
maximal common subgraph problem then is solved by repeated
subgraph extension and checking for isomorphisms. Despite the
apparent inefficiency such approach gives an algorithm with time
complexity proportional to the number of graphs in the input set and is
still practical on the given set of data. As a result we obtain fast
methods which can be used for building a database of protein
topological motifs, and for the comparison of a given protein of known
secondary structure against a motif database
A wireless ECG plaster for real-time cardiac health monitoring in body sensor networks
10.1109/BioCAS.2011.61077632011 IEEE Biomedical Circuits and Systems Conference, BioCAS 2011205-20
Tunnel shotcrete lining for hydroelectric projects in British Columbia
In British Columbia (BC), Canada, the primary source of power supply is hydroelectricity. The BC government, through its crown corporation, BC Hydro, has been working with private companies to provide sustainable and renewable energy. Private companies are building hydroelectric projects throughout the province of BC. Innergex has been constructing three hydroelectric projects; two are in the Upper Lilllooet area, which is about 250 km north of Vancouver and 80km north of Whistler and the third is in the Big Silver area, which is about 250 km east of Vancouver and 50 km north of Harrison Lake. All of these tunnels are hard rock and have been constructed by the drill and blast method. At the beginning of the projects, dry-mix shotcrete was applied based on the contractor’s previous underground project experience. Wet-mix shotcrete was subsequently introduced as a trial method. The contractor was impressed with its productivity and performance and consequently adopted it as the primary shotcrete placement method. Dry-mix steel fiber reinforced shotcrete continued to be used for special ground conditions. The construction schedule was reduced significantly by using wet-mix shotcrete, with resultant substantial cost savings. The wet-mix shotcrete was initially reinforced with wire mesh and hand-applied. Shortly after, the tunnel lining method was changed to the use of robotic sprayed macrosynthetic fiber reinforced wet-mix shotcrete. A silica fume modified shotcrete mixture was designed and trial shot. Tests results met the project specification requirements for tunnel construction. The wet-mix macrosynthetic fiber reinforced shotcrete was placed, since July 2013, using pre-bagged materials supplied from Vancouver and mixed on site. Later, the contractor set up a dry-batch concrete batch plant on site and started batching shotcrete using local aggregates. The shotcrete mixture was qualified for use on the project by testing for compressive strength, boiled absorption and volume of permeable voids, and flexural toughness based on use of the round determinate panel to ASTM C1550. The effect on shotcrete performance of different addition rates of alkali-free accelerator was tested in trials. An addition rate of 6% alkali-free accelerator by mass of cement was selected and used. Shotcrete nozzlemen were trained with a specially designed shotcrete training program. All shotcrete nozzlemen were qualified to shoot a basic Level I, and a more challenging Level II, for shotcrete with reinforcing steel or lattice girders. The construction quality control tests results for the project from August 2013 to December 2016 demonstrated that the shotcrete quality consistently met the project specification requirements. The projects were completed ahead of schedule because of productivity gains achieved from using wet-mix macrosynthetic fiber reinforced shotcrete. The contractors developed proper skills and techniques for application of wet-mix macrosynthetic fiber reinforced shotcrete applied by robotic sprayers with zero safety incidents or accident
Physics of Psychophysics: Stevens and Weber-Fechner laws are transfer functions of excitable media
Sensory arrays made of coupled excitable elements can improve both their
input sensitivity and dynamic range due to collective non-linear wave
properties. This mechanism is studied in a neural network of electrically
coupled (e.g. via gap junctions) elements subject to a Poisson signal process.
The network response interpolates between a Weber-Fechner logarithmic law and a
Stevens power law depending on the relative refractory period of the cell.
Therefore, these non-linear transformations of the input level could be
performed in the sensory periphery simply due to a basic property: the transfer
function of excitable media.Comment: 4 pages, 5 figure
Issues and Observations on Applications of the Constrained-Path Monte Carlo Method to Many-Fermion Systems
We report several important observations that underscore the distinctions
between the constrained-path Monte Carlo method and the continuum and lattice
versions of the fixed-node method. The main distinctions stem from the
differences in the state space in which the random walk occurs and in the
manner in which the random walkers are constrained. One consequence is that in
the constrained-path method the so-called mixed estimator for the energy is not
an upper bound to the exact energy, as previously claimed. Several ways of
producing an energy upper bound are given, and relevant methodological aspects
are illustrated with simple examples.Comment: 28 pages, REVTEX, 5 ps figure
Very long optical path-length from a compact multi-pass cell
The multiple-pass optical cell is an important tool for laser absorption
spectroscopy and its many applications. For most practical applications, such
as trace-gas detection, a compact and robust design is essential. Here we
report an investigation into a multi-pass cell design based on a pair of
cylindrical mirrors, with a particular focus on achieving very long optical
paths. We demonstrate a path-length of 50.31 m in a cell with 40 mm diameter
mirrors spaced 88.9 mm apart - a 3-fold increase over the previously reported
longest path-length obtained with this type of cell configuration. We
characterize the mechanical stability of the cell and describe the practical
conditions necessary to achieve very long path-lengths
A polarized beam splitter using an anisotropic medium slab
The propagation of electromagnetic waves in the anisotropic medium with a
single-sheeted hyperboloid dispersion relation is investigated. It is found
that in such an anisotropic medium E- and H-polarized waves have the same
dispersion relation, while E- and H-polarized waves exhibit opposite amphoteric
refraction characteristics. E- (or H-) polarized waves are positively refracted
whereas H- (or E-) polarized waves are negatively refracted at the interface
associated with the anisotropic medium. By suitably using the properties of
anomalous refraction in the anisotropic medium it is possible to realize a very
simple and very efficient beam splitter to route the light. It is shown that
the splitting angle and the splitting distance between E- and H- polarized beam
is the function of anisotropic parameters, incident angle and slab thickness.Comment: 14 pages, 6 figure
Comparison of Structural Development and Biochemical Accumulation of Waxy and Non-waxy Wheat Caryopses
This study was conducted to compare structural development and biochemical accumulation of waxy and non-waxy wheat (NW) caryopses. The caryopses’ microstructure of the waxy wheat (WW) and NW cultivars at different developmental stages were observed under light, fluorescence, and scanning electron microscope. The results were as follows: Compared with NW,WWhad a shorter maturation duration, which was reflected in several following characteristics. Programmed cell death of the pericarp began earlier, and the chlorophyll-containing layer in the pericarp was smaller. Vacuoles in chalazal cells accumulated more tannins at different developmental stages. Starch granules and protein bodies in the endosperm showed a higher accumulation level in developing caryopses, and aleurone cells were larger in size with larger numbers of aleurone grains. An analysis of the element content indicated that the mineral elements Mg, P, K, and Ca exhibited a higher content, while the heavy elements Cr, Cd, and Pb exhibited a lower content in the aleurone layer
Source population synthesis and the Galactic diffuse gamma-ray emission
Population synthesis is used to study the contribution from undetected
sources to the Galactic ridge emission measured by EGRET. Synthesized source
counts are compared with the 3rd EGRET catalogue at low and high latitudes. For
pulsar-like populations, 5-10% of the emission >100 MeV comes from sources
below the EGRET threshold. A steeper luminosity function can increase this to
20% without violating EGRET source statistics. Less luminous populations can
produce much higher values without being detected. Since the unresolved source
spectrum is different from the interstellar spectrum, it could provide an
explanation of the observed MeV and GeV excesses above the predictions, and we
give an explicit example of how this could work.Comment: Astrophysics and Space Science, in press. (Proceedings of Conference
'The multi-messenger approach to high-energy gamma-ray sources', Barcelona,
2006). Minor changes for accepted version, updated reference
Hydrodynamics of Spatially Ordered Superfluids
We derive the hydrodynamic equations for the supersolid and superhexatic
phases of a neutral two-dimensional Bose fluid. We find, assuming that the
normal part of the fluid is clamped to an underlying substrate, that both
phases can sustain third-sound modes and that in the supersolid phase there are
additional modes due to the superfluid motion of point defects (vacancies and
interstitials).Comment: 24 pages of ReVTeX and 7 uuencoded figures. Submitted for publication
in Phys. Rev.
- …