The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Joakim Dillner - One of the best experts on this subject based on the ideXlab platform.
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triage of women with equivocal or low grade cervical cytology results a meta analysis of the hpv test Positivity rate
Journal of Cellular and Molecular Medicine, 2009Co-Authors: Marc Arbyn, Pierre L Martinhirsch, Frank Buntinx, Marc Van Ranst, Evangelos Paraskevaidis, Joakim DillnerAbstract:Consistent evidence underlines the utility of human papillomavirus (HPV) DNA testing in the management of women with equivocal cervical cytological abnormalities, but not in case of low-grade lesions. We performed a meta-analysis including studies where the high-risk probe of the Hybrid Capture-II is used to triage these two cytological categories. The triage test-Positivity rate reflects the colposcopy referral workload.Data were pooled on the HPV test Positivity rate in women with atypical squamous cells of undetermined significance (ASCUS/ASC-US) or low-grade squamous intraepithelial lesions (LSIL), derived from different cytological classification systems. The meta-analysis was restricted to studies, published between 1991 and 2007. A random-effect model was applied for meta-analytical pooling and the influence of covariates on the HPV Positivity rate was analyzed by meta-regression. The variation by age was assessed within individual studies since age strata were not defined uniformly. On an average, 43% (95% CI: 40–46%) of women with ASCUS/ASC-US were high-risk HPV positive (range 23–74%). In women with LSIL, the pooled Positivity rate was 76% (95% CI: 71–81%; range 55–89%). In spite of considerable inter-study heterogeneity, the difference in HPV Positivity between the two triage groups was large and highly significant: 32% (95% CI: 27–38%). HPV rates dropped tremendously as age and cutoffs of test Positivity increased. Other factors (cytological classification system, country, continent, collection method and year of publication) had no statistically significant impact, except in LSIL triage where HPV Positivity was significantly lower in European compared to American studies. Women with LSIL, especially younger women, have high HPV Positivity rates suggesting limited utility of reflex HPV triaging these cases. Research is needed to identify more specific methods to triage women with low-grade squamous cervical lesions.
Arthur Jaffe - One of the best experts on this subject based on the ideXlab platform.
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reflection Positivity and levin wen models
Expositiones Mathematicae, 2020Co-Authors: Arthur Jaffe, Zhengwei LiuAbstract:Abstract We give a transparent algebraic formulation of our pictorial approach to the reflection Positivity (RP), that we introduced in a previous paper. We apply this quantization to the 2 + 1 Levin–Wen model to obtain 1 + 1 anyonic/quantum spin chain theory on the boundary, possibly entangled in the bulk. The reflection Positivity property has played a central role in both mathematics and physics, as well as providing a crucial link between the two subjects. In a previous paper we gave a new geometric approach to understanding reflection Positivity in terms of pictures. Here we give a transparent algebraic formulation of our pictorial approach. We use insights from this translation to establish the reflection Positivity property for the fashionable Levin–Wen models with respect both to vacuum and to bulk excitations. We believe these methods will be useful for understanding a variety of other problems.
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reflection Positivity and levin wen models
arXiv: Mathematical Physics, 2019Co-Authors: Arthur Jaffe, Zhengwei LiuAbstract:The reflection Positivity property has played a central role in both mathematics and physics, as well as providing a crucial link between the two subjects. In a previous paper we gave a new geometric approach to understanding reflection Positivity in terms of pictures. Here we give a transparent algebraic formulation of our pictorial approach. We use insights from this translation to establish the reflection Positivity property for the fashionable Levin-Wen models with respect both to vacuum and to bulk excitations. We believe these methods will be useful for understanding a variety of other problems.
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planar para algebras reflection Positivity
Communications in Mathematical Physics, 2017Co-Authors: Arthur Jaffe, Zhengwei LiuAbstract:We define a planar para algebra, which arises naturally from combining planar algebras with the idea of \({\mathbb{Z}_{N}}\) para symmetry in physics. A subfactor planar para algebra is a Hilbert space representation of planar tangles with parafermionic defects that are invariant under para isotopy. For each \({\mathbb{Z}_{N}}\), we construct a family of subfactor planar para algebras that play the role of Temperley–Lieb–Jones planar algebras. The first example in this family is the parafermion planar para algebra (PAPPA). Based on this example, we introduce parafermion Pauli matrices, quaternion relations, and braided relations for parafermion algebras, which one can use in the study of quantum information. An important ingredient in planar para algebra theory is the string Fourier transform (SFT), which we use on the matrix algebra generated by the Pauli matrices. Two different reflections play an important role in the theory of planar para algebras. One is the adjoint operator; the other is the modular conjugation in Tomita–Takesaki theory. We use the latter one to define the double algebra and to introduce reflection Positivity. We give a new and geometric proof of reflection Positivity by relating the two reflections through the string Fourier transform.
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reflection Positivity for parafermions
Communications in Mathematical Physics, 2015Co-Authors: Arthur Jaffe, Fabio L. PedrocchiAbstract:We establish reflection Positivity for Gibbs trace states for a class of gauge-invariant, reflection-invariant Hamiltonians describing parafermion interactions on a lattice. We relate these results to recent work in the condensed-matter physics literature.
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Topological order and reflection Positivity
EPL, 2014Co-Authors: Arthur Jaffe, Fabio L. PedrocchiAbstract:The focus of this paper is twofold. First, we observe that Hamiltonians displaying both topological order and reflection Positivity have an interesting property: expectations in different ground-state vectors of a given local operator WA have the same sign. Secondly, we illustrate this result with a specific Majorana Hamiltonian, related to the toric code which is widely studied in quantum information theory. We show that expectations of reflection-symmetric loops in ground states of this Hamiltonian are vortex-free or vortex-full.
Marc Arbyn - One of the best experts on this subject based on the ideXlab platform.
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triage of women with equivocal or low grade cervical cytology results a meta analysis of the hpv test Positivity rate
Journal of Cellular and Molecular Medicine, 2009Co-Authors: Marc Arbyn, Pierre L Martinhirsch, Frank Buntinx, Marc Van Ranst, Evangelos Paraskevaidis, Joakim DillnerAbstract:Consistent evidence underlines the utility of human papillomavirus (HPV) DNA testing in the management of women with equivocal cervical cytological abnormalities, but not in case of low-grade lesions. We performed a meta-analysis including studies where the high-risk probe of the Hybrid Capture-II is used to triage these two cytological categories. The triage test-Positivity rate reflects the colposcopy referral workload.Data were pooled on the HPV test Positivity rate in women with atypical squamous cells of undetermined significance (ASCUS/ASC-US) or low-grade squamous intraepithelial lesions (LSIL), derived from different cytological classification systems. The meta-analysis was restricted to studies, published between 1991 and 2007. A random-effect model was applied for meta-analytical pooling and the influence of covariates on the HPV Positivity rate was analyzed by meta-regression. The variation by age was assessed within individual studies since age strata were not defined uniformly. On an average, 43% (95% CI: 40–46%) of women with ASCUS/ASC-US were high-risk HPV positive (range 23–74%). In women with LSIL, the pooled Positivity rate was 76% (95% CI: 71–81%; range 55–89%). In spite of considerable inter-study heterogeneity, the difference in HPV Positivity between the two triage groups was large and highly significant: 32% (95% CI: 27–38%). HPV rates dropped tremendously as age and cutoffs of test Positivity increased. Other factors (cytological classification system, country, continent, collection method and year of publication) had no statistically significant impact, except in LSIL triage where HPV Positivity was significantly lower in European compared to American studies. Women with LSIL, especially younger women, have high HPV Positivity rates suggesting limited utility of reflex HPV triaging these cases. Research is needed to identify more specific methods to triage women with low-grade squamous cervical lesions.
Murray Marshall - One of the best experts on this subject based on the ideXlab platform.
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Positivity IN POWER SERIES RINGS
Advances in Geometry, 2010Co-Authors: Jaka Cimpric, Salma Kuhlmann, Murray MarshallAbstract:We extend and generalize results of Scheiderer (2006) on the representation of polynomials nonnegative on two-dimensional basic closed semialgebraic sets. Our extension covers some situations where the defining polynomials do not satisfy the transversality condition. Such situations arise naturally when one considers semialgebraic sets invariant under finite group actions.Peer Reviewe
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Positivity in power series rings
arXiv: Algebraic Geometry, 2008Co-Authors: Jaka Cimpric, Salma Kuhlmann, Murray MarshallAbstract:We extend and generalize the results of Scheiderer (2006) on the representation of polynomials nonnegative on two-dimensional basic closed semialgebraic sets. Our extension covers some situations where the defining polynomials do not satisfy the transversality condition. Such situations arise naturally when one considers semialgebraic sets invariant under finite group actions.
Tadeusz Kaczorek - One of the best experts on this subject based on the ideXlab platform.
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Positivity of Fractional Descriptor Linear Discrete–Time Systems
International Journal of Applied Mathematics and Computer Science, 2019Co-Authors: Tadeusz KaczorekAbstract:Abstract The Positivity of fractional descriptor linear discrete-time systems is investigated. The solution to the state equation of the systems is derived. Necessary and sufficient conditions for the Positivity of fractional descriptor linear discrete-time systems are established. The discussion is illustrated with numerical examples.
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AUTOMATION - Descriptor Positive Nonlinear Systems
Automation 2017, 2017Co-Authors: Tadeusz KaczorekAbstract:The Positivity of discrete-time and continuous-time nonlinear systems is addressed. Necessary and sufficient conditions for the Positivity of the descriptor nonlinear systems are established. A procedure for checking the Positivity is proposed and demonstrated on numerical examples.