892 research outputs found
Human Tâcell lymphotrophic virus in solidâorgan transplant recipients: Guidelines from the American society of transplantation infectious diseases community of practice
These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of Human Tâcell lymphotrophic virus 1 (HTLV)â1 in the preâ and postâtransplant period. HTLVâ1 is an oncogenic human retrovirus rare in North America but endemic in the Caribbean and parts of Africa, South America, Asia, and Oceania. While most infected persons do not develop disease, <5% will develop adult Tâcell leukemia/lymphoma or neurological disease. No proven antiviral treatment for established HTLVâ1 infection is available. The effect of immunosuppression on the development of HTLVâ1âassociated disease in asymptomatically infected recipients is not well characterized, and HTLVâ1âinfected individuals should be counseled that immunosuppression may increase the risk of developing HTLVâ1âassociated disease and they should be monitored postâtransplant for HTLVâ1âassociated disease. Currently approved screening assays do not distinguish between HTLVâ1 and HTLVâ2, and routine screening of deceased donors without risk factors in low seroprevalence areas is likely to result in significant organ wastage and is not recommended. Targeted screening of donors with risk factors for HTLVâ1 infection and of living donors (as time is available to perform confirmatory tests) is reasonable.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151899/1/ctr13575.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151899/2/ctr13575_am.pd
Recommendation model based on opinion diffusion
Information overload in the modern society calls for highly efficient
recommendation algorithms. In this letter we present a novel diffusion based
recommendation model, with users' ratings built into a transition matrix. To
speed up computation we introduce a Green function method. The numerical tests
on a benchmark database show that our prediction is superior to the standard
recommendation methods.Comment: 5 pages, 2 figure
On Functionality of Visibly Pushdown Transducers
Visibly pushdown transducers form a subclass of pushdown transducers that
(strictly) extends finite state transducers with a stack. Like visibly pushdown
automata, the input symbols determine the stack operations. In this paper, we
prove that functionality is decidable in PSpace for visibly pushdown
transducers. The proof is done via a pumping argument: if a word with two
outputs has a sufficiently large nesting depth, there exists a nested word with
two outputs whose nesting depth is strictly smaller. The proof uses technics of
word combinatorics. As a consequence of decidability of functionality, we also
show that equivalence of functional visibly pushdown transducers is
Exptime-Complete.Comment: 20 page
Graded contractions and bicrossproduct structure of deformed inhomogeneous algebras
A family of deformed Hopf algebras corresponding to the classical maximal
isometry algebras of zero-curvature N-dimensional spaces (the inhomogeneous
algebras iso(p,q), p+q=N, as well as some of their contractions) are shown to
have a bicrossproduct structure. This is done for both the algebra and, in a
low-dimensional example, for the (dual) group aspects of the deformation.Comment: LaTeX file, 20 pages. Trivial changes. To appear in J. Phys.
Covariant scalar representation of quantization of the scalar relativistic particle
A covariant scalar representation of is constructed and
analysed in comparison with existing methods for the quantization of the scalar
relativistic particle. It is found that, with appropriately defined
wavefunctions, this produced representation can be identified
with the state space arising from the canonical BFV-BRST quantization of the
modular invariant, unoriented scalar particle (or antiparticle) with admissible
gauge fixing conditions. For this model, the cohomological determination of
physical states can thus be obtained purely from the representation theory of
the algebra.Comment: 16 pages Late
New stopping criteria for segmenting DNA sequences
We propose a solution on the stopping criterion in segmenting inhomogeneous
DNA sequences with complex statistical patterns. This new stopping criterion is
based on Bayesian Information Criterion (BIC) in the model selection framework.
When this stopping criterion is applied to a left telomere sequence of yeast
Saccharomyces cerevisiae and the complete genome sequence of bacterium
Escherichia coli, borders of biologically meaningful units were identified
(e.g. subtelomeric units, replication origin, and replication terminus), and a
more reasonable number of domains was obtained. We also introduce a measure
called segmentation strength which can be used to control the delineation of
large domains. The relationship between the average domain size and the
threshold of segmentation strength is determined for several genome sequences.Comment: 4 pages, 4 figures, Physical Review Letters, to appea
Bicrossproduct construction versus Weyl-Heisenberg algebra
We are focused on detailed analysis of the Weyl-Heisenberg algebra in the
framework of bicrossproduct construction. We argue that however it is not
possible to introduce full bialgebra structure in this case, it is possible to
introduce non-counital bialgebra counterpart of this construction. Some remarks
concerning bicrossproduct basis for kappa-Poincare Hopf algebra are also
presented.Comment: 11 pages, contribution to the proceedings of the 7th International
Conference on Quantum Theory and Symmetries (QTS7), 7-13 August 2011, Prague,
Czech Republi
Progenitor-Derivative Relationships of Hordeum Polyploids (Poaceae, Triticeae) Inferred from Sequences of TOPO6, a Nuclear Low-Copy Gene Region
Polyploidization is a major mechanism of speciation in plants. Within the barley genus Hordeum, approximately half of the taxa are polyploids. While for diploid species a good hypothesis of phylogenetic relationships exists, there is little information available for the polyploids (4Ă, 6Ă) of Hordeum. Relationships among all 33 diploid and polyploid Hordeum species were analyzed with the low-copy nuclear marker region TOPO6 for 341 Hordeum individuals and eight outgroup species. PCR products were either directly sequenced or cloned and on average 12 clones per individual were included in phylogenetic analyses. In most diploid Hordeum species TOPO6 is probably a single-copy locus. Most sequences found in polyploid individuals phylogenetically cluster together with sequences derived from diploid species and thus allow the identification of parental taxa of polyploids. Four groups of sequences occurring only in polyploid taxa are interpreted as footprints of extinct diploid taxa, which contributed to allopolyploid evolution. Our analysis identifies three key species involved in the evolution of the American polyploids of the genus. (i) All but one of the American tetraploids have a TOPO6 copy originating from the Central Asian diploid H. roshevitzii, the second copy clustering with different American diploid species. (ii) All hexaploid species from the New World have a copy of an extinct close relative of H. californicum and (iii) possess the TOPO6 sequence pattern of tetraploid H. jubatum, each with an additional copy derived from different American diploids. Tetraploid H. bulbosum is an autopolyploid, while the assumed autopolyploid H. brevisubulatum (4Ă, 6Ă) was identified as allopolyploid throughout most of its distribution area. The use of a proof-reading DNA polymerase in PCR reduced the proportion of chimerical sequences in polyploids in comparison to Taq polymerase
Hypergraph model of social tagging networks
The past few years have witnessed the great success of a new family of
paradigms, so-called folksonomy, which allows users to freely associate tags to
resources and efficiently manage them. In order to uncover the underlying
structures and user behaviors in folksonomy, in this paper, we propose an
evolutionary hypergrah model to explain the emerging statistical properties.
The present model introduces a novel mechanism that one can not only assign
tags to resources, but also retrieve resources via collaborative tags. We then
compare the model with a real-world dataset: \emph{Del.icio.us}. Indeed, the
present model shows considerable agreement with the empirical data in following
aspects: power-law hyperdegree distributions, negtive correlation between
clustering coefficients and hyperdegrees, and small average distances.
Furthermore, the model indicates that most tagging behaviors are motivated by
labeling tags to resources, and tags play a significant role in effectively
retrieving interesting resources and making acquaintance with congenial
friends. The proposed model may shed some light on the in-depth understanding
of the structure and function of folksonomy.Comment: 7 pages,7 figures, 32 reference
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