419 research outputs found

    Comparison maps for relatively free resolutions

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    Let Λ be a commutative ring, A an augmented differential graded algebra over Λ (briefly, DGA-algebra) and X be a relatively free resolution of Λ over A. The standard bar resolution of Λ over A, denoted by B(A), provides an example of a resolution of this kind. The comparison theorem gives inductive formulae f : B(A)→X and g : X→B(A) termed comparison maps. In case that fg=1 X and A is connected, we show that X is endowed a A  ∞ -tensor product structure. In case that A is in addition commutative then (X,μ X ) is shown to be a commutative DGA-algebra with the product μ X =f*(g⊗g) (* is the shuffle product in B(A)). Furthermore, f and g are algebra maps. We give an example in order to illustrate the main results of this paper

    Resonant multiple Andreev reflections in mesoscopic superconducting junctions

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    We investigate the properties of subharmonic gap structure (SGS) in superconducting quantum contacts with normal-electron resonances. We find two distinct new features of the SGS in resonant junctions which distinguish them from non-resonant point contacts: (i) The odd-order structures on the current-voltage characteristics of resonant junctions are strongly enhanced and have pronounced peaks, while the even-order structures are suppressed, in the case of a normal electron resonance being close to the Fermi level. (ii) Tremendous current peaks develop at eV=±2E0eV=\pm 2E_0 where E0E_0 indicates a distance of the resonance to the Fermi level. These properties are determined by the effect of narrowing of the resonance during multiple Andreev reflections and by overlap of electron and hole resonances.Comment: 13 pages, 10 figure

    The arctic curve of the domain-wall six-vertex model

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    The problem of the form of the `arctic' curve of the six-vertex model with domain wall boundary conditions in its disordered regime is addressed. It is well-known that in the scaling limit the model exhibits phase-separation, with regions of order and disorder sharply separated by a smooth curve, called the arctic curve. To find this curve, we study a multiple integral representation for the emptiness formation probability, a correlation function devised to detect spatial transition from order to disorder. We conjecture that the arctic curve, for arbitrary choice of the vertex weights, can be characterized by the condition of condensation of almost all roots of the corresponding saddle-point equations at the same, known, value. In explicit calculations we restrict to the disordered regime for which we have been able to compute the scaling limit of certain generating function entering the saddle-point equations. The arctic curve is obtained in parametric form and appears to be a non-algebraic curve in general; it turns into an algebraic one in the so-called root-of-unity cases. The arctic curve is also discussed in application to the limit shape of qq-enumerated (with 0<q40<q\leq 4) large alternating sign matrices. In particular, as q0q\to 0 the limit shape tends to a nontrivial limiting curve, given by a relatively simple equation.Comment: 39 pages, 2 figures; minor correction

    Coherent electron-phonon coupling and polaron-like transport in molecular wires

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    We present a technique to calculate the transport properties through one-dimensional models of molecular wires. The calculations include inelastic electron scattering due to electron-lattice interaction. The coupling between the electron and the lattice is crucial to determine the transport properties in one-dimensional systems subject to Peierls transition since it drives the transition itself. The electron-phonon coupling is treated as a quantum coherent process, in the sense that no random dephasing due to electron-phonon interactions is introduced in the scattering wave functions. We show that charge carrier injection, even in the tunneling regime, induces lattice distortions localized around the tunneling electron. The transport in the molecular wire is due to polaron-like propagation. We show typical examples of the lattice distortions induced by charge injection into the wire. In the tunneling regime, the electron transmission is strongly enhanced in comparison with the case of elastic scattering through the undistorted molecular wire. We also show that although lattice fluctuations modify the electron transmission through the wire, the modifications are qualitatively different from those obtained by the quantum electron-phonon inelastic scattering technique. Our results should hold in principle for other one-dimensional atomic-scale wires subject to Peierls transitions.Comment: 21 pages, 8 figures, accepted for publication in Phys. Rev. B (to appear march 2001

    Genome‐wide association study of INDELs identified four novel susceptibility loci associated with lung cancer risk

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    Genome‐wide association studies (GWAS) have identified 45 susceptibility loci associated with lung cancer. Only less than SNPs, small insertions and deletions (INDELs) are the second most abundant genetic polymorphisms in the human genome. INDELs are highly associated with multiple human diseases, including lung cancer. However, limited studies with large‐scale samples have been available to systematically evaluate the effects of INDELs on lung cancer risk. Here, we performed a large‐scale meta‐analysis to evaluate INDELs and their risk for lung cancer in 23,202 cases and 19,048 controls. Functional annotations were performed to further explore the potential function of lung cancer risk INDELs. Conditional analysis was used to clarify the relationship between INDELs and SNPs. Four new risk loci were identified in genome‐wide INDEL analysis (1p13.2: rs5777156, Insertion, OR = 0.92, P = 9.10 × 10−8; 4q28.2: rs58404727, Deletion, OR = 1.19, P = 5.25 × 10−7; 12p13.31: rs71450133, Deletion, OR = 1.09, P = 8.83 × 10−7; and 14q22.3: rs34057993, Deletion, OR = 0.90, P = 7.64 × 10−8). The eQTL analysis and functional annotation suggested that INDELs might affect lung cancer susceptibility by regulating the expression of target genes. After conducting conditional analysis on potential causal SNPs, the INDELs in the new loci were still nominally significant. Our findings indicate that INDELs could be potentially functional genetic variants for lung cancer risk. Further functional experiments are needed to better understand INDEL mechanisms in carcinogenesis

    Systemic treatment of children and adolescents with atopic dermatitis aged ≥2 years : a Delphi consensus project mapping expert opinion in Northern Europe

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    Publisher Copyright: © 2022 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology.Background: Paediatric atopic dermatitis (AD) can be burdensome, affecting mental health and impairing quality of life for children and caregivers. Comprehensive guidelines exist for managing paediatric AD, but practical guidance on using systemic therapy is limited, particularly for new therapies including biologics and Janus kinase (JAK) inhibitors, recently approved for various ages in this indication. Objectives: This expert consensus aimed to provide practical recommendations within this advancing field to enhance clinical decision-making on the use of these and other systemics for children and adolescents aged ≥2 years with moderate-to-severe AD. Methods: Nineteen physicians from Northern Europe were selected for their expertise in managing childhood AD. Using a two-round Delphi process, they reached full or partial consensus on 37 statements. Results: Systemic therapy is recommended for children aged ≥2 years with a clear clinical diagnosis of severe AD and persistent disease uncontrolled after optimizing non-systemic therapy. Systemic therapy should achieve long-term disease control and reduce short-term interventions. Recommended are cyclosporine A for short-term use (all ages) and dupilumab or methotrexate for long-term use (ages ≥6 years). Consensus was not reached on the best long-term systemics for children aged 2–6 years, although new systemic therapies will likely become favourable: New biologics and JAK inhibitors will soon be approved for this age group, and more trial and real-world data will become available. Conclusions: This article makes practical recommendations on the use of systemic AD treatments for children and adolescents, to supplement international and regional guidelines. It considers the systemic medication that was available for children and adolescents with moderate-to-severe AD at the time this consensus project was done: azathioprine, cyclosporine A, dupilumab, methotrexate, mycophenolate mofetil and oral glucocorticosteroids. We focus on the geographically similar Northern European countries, whose healthcare systems, local preferences for AD management and reimbursement structures nonetheless differ significantly.Peer reviewe
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