41,713 research outputs found
Electronic and magnetic properties of V-doped anatase TiO from first principles
We report a first-principles study on the geometric, electronic and magnetic
properties of V-doped anatase TiO. The DFT+U (Hubbard coefficient)
approach predicts semiconductor band structures for TiVO
(x=6.25 and 12.5%), in good agreement with the poor conductivity of samples,
while the standard calculation within generalized gradient approximation fails.
Theoretical results show that V atoms tend to stay close and result in strong
ferromagnetism through superexchange interactions. Oxygen vacancy induced
magnetic polaron could produce long-range ferromagnetic interaction between
largely separated magnetic impurities. The experimentally observed
ferromagnetism in V-doped anatase TiO at room temperature may originate
from a combination of short-range superexchange coupling and long-range bound
magnetic polaron percolation.Comment: 12 pages and 4 figures (to be appeared in PRB as a brief report
Microbial community pattern detection in human body habitats via ensemble clustering framework
The human habitat is a host where microbial species evolve, function, and
continue to evolve. Elucidating how microbial communities respond to human
habitats is a fundamental and critical task, as establishing baselines of human
microbiome is essential in understanding its role in human disease and health.
However, current studies usually overlook a complex and interconnected
landscape of human microbiome and limit the ability in particular body habitats
with learning models of specific criterion. Therefore, these methods could not
capture the real-world underlying microbial patterns effectively. To obtain a
comprehensive view, we propose a novel ensemble clustering framework to mine
the structure of microbial community pattern on large-scale metagenomic data.
Particularly, we first build a microbial similarity network via integrating
1920 metagenomic samples from three body habitats of healthy adults. Then a
novel symmetric Nonnegative Matrix Factorization (NMF) based ensemble model is
proposed and applied onto the network to detect clustering pattern. Extensive
experiments are conducted to evaluate the effectiveness of our model on
deriving microbial community with respect to body habitat and host gender. From
clustering results, we observed that body habitat exhibits a strong bound but
non-unique microbial structural patterns. Meanwhile, human microbiome reveals
different degree of structural variations over body habitat and host gender. In
summary, our ensemble clustering framework could efficiently explore integrated
clustering results to accurately identify microbial communities, and provide a
comprehensive view for a set of microbial communities. Such trends depict an
integrated biography of microbial communities, which offer a new insight
towards uncovering pathogenic model of human microbiome.Comment: BMC Systems Biology 201
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