10,941 research outputs found
A methodological proposal to investigate the long term storage of pollutants in freshwater sediment biofilms and their response to environmental disturbances.
This research will review novel methodologies for understanding the behaviour of microbial communities and their role in pollution storage. Freshwater sediments are inhabited by attached microbial communities (biofilms) which are responsible for the majority of a river's metabolic activity. Biofilms thus provide valuable information on the environmental quality of the river and its surrounding areas. Despite remediation of freshwater sediments, biofilms can still store large quantities of pollutants. Biofilms have the exceptional capacity to adjust to new conditions including natural and anthropogenic environmental disturbances. Gaining a more comprehensive understanding of biofilm behaviour is therefore fundamental to developing improved management strategies. The initial focus of this research will be in the River Doe Lea in North East Derbyshire. The River Doe Lea extends 18km from the South at its source near Tibshelf, to the North at its discharge at the River Rother. In the 1990s the River was famed for having the highest level of dioxins in the world, 27 times higher than the second most polluted. The acute cause of this was a single pollutant event, however the river has also been subjected to long term anthropogenic pollution through industry, agriculture, transport (railways, M1) and wastewater pollution. While previous studies by the Environment Agency have focused on the flow, chemical, biological and ecological quality of the river, no research has been conducted into the role and behaviour of biofilms
Topological Bose-Mott Insulators in a One-Dimensional Optical Superlattice
We study topological properties of the Bose-Hubbard model with repulsive
interactions in a one-dimensional optical superlattice. We find that the Mott
insulator states of the single-component (two-component) Bose-Hubbard model
under fractional fillings are topological insulators characterized by a nonzero
charge (or spin) Chern number with nontrivial edge states. For ultracold atomic
experiments, we show that the topological Chern number can be detected through
measuring the density profiles of the bosonic atoms in a harmonic trap.Comment: 5 pages, published versio
Similarity measuring between patient traces for clinical pathway analysis
Clinical pathways leave traces, described as activity sequences with regard to a mixture of various latent treatment behaviors. Measuring similarities between patient traces can profitably be exploited further as a basis for providing insights into the pathways, and complementing existing techniques of clinical pathway analysis, which mainly focus on looking at aggregated data seen from an external perspective. In this paper, a probabilistic graphical model, i.e., Latent Dirichlet Allocation, is employed to discover latent treatment behaviors of patient traces for clinical pathways such that similarities of pairwise patient traces can be measured based on their underlying behavioral topical features. The presented method, as a basis for further tasks in clinical pathway analysis, are evaluated via a real-world data-set collected from a Chinese hospital
Similarity measuring between patient traces for clinical pathway analysis
Clinical pathways leave traces, described as activity sequences with regard to a mixture of various latent treatment behaviors. Measuring similarities between patient traces can profitably be exploited further as a basis for providing insights into the pathways, and complementing existing techniques of clinical pathway analysis, which mainly focus on looking at aggregated data seen from an external perspective. In this paper, a probabilistic graphical model, i.e., Latent Dirichlet Allocation, is employed to discover latent treatment behaviors of patient traces for clinical pathways such that similarities of pairwise patient traces can be measured based on their underlying behavioral topical features. The presented method, as a basis for further tasks in clinical pathway analysis, are evaluated via a real-world data-set collected from a Chinese hospital
Influence of uniaxial tensile stress on the mechanical and piezoelectric properties of short-period ferroelectric superlattice
Tetragonal ferroelectric/ferroelectric BaTiO3/PbTiO3 superlattice under
uniaxial tensile stress along the c axis is investigated from first principles.
We show that the calculated ideal tensile strength is 6.85 GPa and that the
superlattice under the loading of uniaxial tensile stress becomes soft along
the nonpolar axes. We also find that the appropriately applied uniaxial tensile
stress can significantly enhance the piezoelectricity for the superlattice,
with piezoelectric coefficient d33 increasing from the ground state value by a
factor of about 8, reaching 678.42 pC/N. The underlying mechanism for the
enhancement of piezoelectricity is discussed
Energy-momentum for Randall-Sundrum models
We investigate the conservation law of energy-momentum for Randall-Sundrum
models by the general displacement transform. The energy-momentum current has a
superpotential and are therefore identically conserved. It is shown that for
Randall-Sundrum solution, the momentum vanishes and most of the bulk energy is
localized near the Planck brane. The energy density is .Comment: 13 pages, no figures, v4: introduction and new conclusion added, v5:
11 pages, title changed and references added, accepted by Mod. Phys. Lett.
Quantum three-body system in D dimensions
The independent eigenstates of the total orbital angular momentum operators
for a three-body system in an arbitrary D-dimensional space are presented by
the method of group theory. The Schr\"{o}dinger equation is reduced to the
generalized radial equations satisfied by the generalized radial functions with
a given total orbital angular momentum denoted by a Young diagram
for the SO(D) group. Only three internal variables are
involved in the functions and equations. The number of both the functions and
the equations for the given angular momentum is finite and equal to
.Comment: 16 pages, no figure, RevTex, Accepted by J. Math. Phy
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