333 research outputs found

    Genomic organization and phylogenetic utility of deer mouse (Peromyscus maniculatus) lymphotoxin-alpha and lymphotoxin-beta

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    <p>Abstract</p> <p>Background</p> <p>Deer mice (<it>Peromyscus maniculatus</it>) are among the most common mammals in North America and are important reservoirs of several human pathogens, including Sin Nombre hantavirus (SNV). SNV can establish a life-long apathogenic infection in deer mice, which can shed virus in excrement for transmission to humans. Patients that die from hantavirus cardiopulmonary syndrome (HCPS) have been found to express several proinflammatory cytokines, including lymphotoxin (LT), in the lungs. It is thought that these cytokines contribute to the pathogenesis of HCPS. LT is not expressed by virus-specific CD4<sup>+ </sup>T cells from infected deer mice, suggesting a limited role for this pathway in reservoir responses to hantaviruses.</p> <p>Results</p> <p>We have cloned the genes encoding deer mouse LTα and LTβ and have found them to be highly similar to orthologous rodent sequences but with some differences in promoters elements. The phylogenetic analyses performed on the LTα, LTβ, and combined data sets yielded a strongly-supported sister-group relationship between the two murines (the house mouse and the rat). The deer mouse, a sigmodontine, appeared as the sister group to the murine clade in all of the analyses. High bootstrap values characterized the grouping of murids.</p> <p>Conclusion</p> <p>No conspicuous differences compared to other species are present in the predicted amino acid sequences of LTα or LTβ; however, some promoter differences were noted in LTβ. Although more extensive taxonomic sampling is required to confirm the results of our analyses, the preliminary findings indicate that both genes (analyzed both separately and in combination) hold potential for resolving relationships among rodents and other mammals at the subfamily level.</p

    Periodic Orbits and Spectral Statistics of Pseudointegrable Billiards

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    We demonstrate for a generic pseudointegrable billiard that the number of periodic orbit families with length less than ll increases as πb0l2/⟨a(l)⟩\pi b_0l^2/\langle a(l) \rangle, where b0b_0 is a constant and ⟨a(l)⟩\langle a(l) \rangle is the average area occupied by these families. We also find that ⟨a(l)⟩\langle a(l) \rangle increases with ll before saturating. Finally, we show that periodic orbits provide a good estimate of spectral correlations in the corresponding quantum spectrum and thus conclude that diffraction effects are not as significant in such studies.Comment: 13 pages in RevTex including 5 figure

    Classical Dynamics of Anyons and the Quantum Spectrum

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    In this paper we show that (a) all the known exact solutions of the problem of N-anyons in oscillator potential precisely arise from the collective degrees of freedom, (b) the system is pseudo-integrable ala Richens and Berry. We conclude that the exact solutions are trivial thermodynamically as well as dynamically.Comment: 19 pages, ReVTeX, IMSc/93/0

    Semiclassical Inequivalence of Polygonalized Billiards

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    Polygonalization of any smooth billiard boundary can be carried out in several ways. We show here that the semiclassical description depends on the polygonalization process and the results can be inequivalent. We also establish that generalized tangent-polygons are closest to the corresponding smooth billiard and for de Broglie wavelengths larger than the average length of the edges, the two are semiclassically equivalent.Comment: revtex, 4 ps figure

    Periodic Orbits in Polygonal Billiards

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    We review some properties of periodic orbit families in polygonal billiards and discuss in particular a sum rule that they obey. In addition, we provide algorithms to determine periodic orbit families and present numerical results that shed new light on the proliferation law and its variation with the genus of the invariant surface. Finally, we deal with correlations in the length spectrum and find that long orbits display Poisson fluctuations.Comment: 30 pages (Latex) including 11 figure

    Semiclassical Quantisation Using Diffractive Orbits

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    Diffraction, in the context of semiclassical mechanics, describes the manner in which quantum mechanics smooths over discontinuities in the classical mechanics. An important example is a billiard with sharp corners; its semiclassical quantisation requires the inclusion of diffractive periodic orbits in addition to classical periodic orbits. In this paper we construct the corresponding zeta function and apply it to a scattering problem which has only diffractive periodic orbits. We find that the resonances are accurately given by the zeros of the diffractive zeta function.Comment: Revtex document. Submitted to PRL. Figures available on reques

    Scale Anomaly and Quantum Chaos in the Billiards with Pointlike Scatterers

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    We argue that the random-matrix like energy spectra found in pseudointegrable billiards with pointlike scatterers are related to the quantum violation of scale invariance of classical analogue system. It is shown that the behavior of the running coupling constant explains the key characteristics of the level statistics of pseudointegrable billiards.Comment: 10 pages, RevTex file, uuencode

    Level spacing distribution of pseudointegrable billiard

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    In this paper, we examine the level spacing distribution P(S)P(S) of the rectangular billiard with a single point-like scatterer, which is known as pseudointegrable. It is shown that the observed P(S)P(S) is a new type, which is quite different from the previous conclusion. Even in the strong coupling limit, the Poisson-like behavior rather than Wigner-like is seen for S>1S>1, although the level repulsion still remains in the small SS region. The difference from the previous works is analyzed in detail.Comment: 11 pages, REVTeX file, 3 PostScript Figure

    Invariant varieties of periodic points for some higher dimensional integrable maps

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    By studying various rational integrable maps on C^d\mathbf{\hat C}^d with pp invariants, we show that periodic points form an invariant variety of dimension ≥p\ge p for each period, in contrast to the case of nonintegrable maps in which they are isolated. We prove the theorem: {\it `If there is an invariant variety of periodic points of some period, there is no set of isolated periodic points of other period in the map.'}Comment: 24 page

    Changes in paediatric respiratory infections at a UK teaching hospital 2016–2021; impact of the SARS-CoV-2 pandemic

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    Objective: To describe the impact of the SARS-CoV-2 pandemic on the incidence of paediatric viral respiratory tract infection in Oxfordshire, UK. Methods: Data on paediatric Emergency Department (ED) attendances (0–15 years inclusive), respiratory virus testing, vital signs and mortality at Oxford University Hospitals were summarised using descriptive statistics. Results: Between 1-March-2016 and 30-July-2021, 155,056 ED attendances occurred and 7,195 respiratory virus PCRs were performed. Detection of all pathogens was suppressed during the first national lockdown. Rhinovirus and adenovirus rates increased when schools reopened September-December 2020, then fell, before rising in March-May 2021. The usual winter RSV peak did not occur in 2020/21, with an inter-seasonal rise (32/1,000 attendances in 0–3 yr olds) in July 2021. Influenza remained suppressed throughout. A higher paediatric early warning score (PEWS) was seen for attendees with adenovirus during the pandemic compared to pre-pandemic (p = 0.04, Mann-Witney U test), no other differences in PEWS were seen. Conclusions: SARS-CoV-2 caused major changes in the incidence of paediatric respiratory viral infection in Oxfordshire, with implications for clinical service demand, testing strategies, timing of palivizumab RSV prophylaxis, and highlighting the need to understand which public health interventions are most effective for preventing respiratory virus infections
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