Differences in clinicopathologic variables between Borrelia C6 antigen seroreactive and Borrelia C6 seronegative glomerulopathy in dogs.

BackgroundRapidly progressive glomerulonephritis has been described in dogs that seroreact to Borrelia burgdorferi, but no studies have compared clinicopathologic differences in Lyme-seroreactive dogs with protein-losing nephropathy (PLN) versus dogs with Borrelia-seronegative PLN.Hypothesis/objectivesDogs with Borrelia C6 antigen-seroreactive PLN have distinct clinicopathologic findings when compared to dogs with Borrelia seronegative PLN.AnimalsForty dogs with PLN and Borrelia C6 antigen seroreactivity and 78 C6-seronegative temporally matched dogs with PLN.MethodsRetrospective prevalence case-control study. Clinical information was retrieved from records of dogs examined at the University of California, Davis, Veterinary Medical Teaching Hospital. Histopathologic findings in renal tissue procured by biopsy or necropsy of dogs with PLN were reviewed.ResultsRetrievers and retriever mixes were overrepresented in seroreactive dogs (P < .001). Seroreactive dogs were more likely to have thrombocytopenia (P < .001), azotemia (P = .002), hyperphosphatemia (P < .001), anemia (P < .001), and neutrophilia (P = .003). Hematuria, glucosuria, and pyuria despite negative urine culture were more likely in seroreactive dogs (all P ≤ .002). Histopathologic findings were consistent with immune-complex glomerulonephritis in 16 of 16 case dogs and 7 of 23 control dogs (P = 006). Prevalence of polyarthritis was not different between groups (P = .17).Conclusions and clinical importanceC6 seroreactivity in dogs with PLN is associated with a clinicopathologically distinct syndrome when compared with other types of PLN. Early recognition of this syndrome has the potential to improve outcomes through specific aggressive and early treatment

Current-sheet formation in incompressible electron magnetohydrodynamics

The nonlinear dynamics of axisymmetric, as well as helical, frozen-in vortex structures is investigated by the Hamiltonian method in the framework of ideal incompressible electron magnetohydrodynamics. For description of current-sheet formation from a smooth initial magnetic field, local and nonlocal nonlinear approximations are introduced and partially analyzed that are generalizations of the previously known exactly solvable local model neglecting electron inertia. Finally, estimations are made that predict finite-time singularity formation for a class of hydrodynamic models intermediate between that local model and the Eulerian hydrodynamics.Comment: REVTEX4, 5 pages, no figures. Introduction rewritten, new material and references adde

Uncertainty estimates and L_2 bounds for the Kuramoto-Sivashinsky equation

We consider the Kuramoto-Sivashinsky (KS) equation in one spatial dimension with periodic boundary conditions. We apply a Lyapunov function argument similar to the one first introduced by Nicolaenko, Scheurer, and Temam, and later improved by Collet, Eckmann, Epstein and Stubbe, and Goodman, to prove that ||u||_2 < C L^1.5. This result is slightly weaker than that recently announced by Giacomelli and Otto, but applies in the presence of an additional linear destabilizing term. We further show that for a large class of Lyapunov functions \phi the exponent 1.5 is the best possible from this line of argument. Further, this result together with a result of Molinet gives an improved estimate for L_2 boundedness of the Kuramoto-Sivashinsky equation in thin rectangular domains in two spatial dimensions.Comment: 17 pages, 1 figure; typos corrected, references added; figure modifie

First observation of spin-helical Dirac fermions and topological phases in undoped and doped Bi2Te3 demonstrated by spin-ARPES spectroscopy

Electron systems that possess light-like dispersion relations or the conical Dirac spectrum, such as graphene and bismuth, have recently been shown to harbor unusual collective states in high magnetic fields. Such states are possible because their light-like electrons come in spin pairs that are chiral,which means that their direction of propagation is tied to a quantity called pseudospin that describes their location in the crystal lattice. An emerging direction in quantum materials research is the manipulation of atomic spin-orbit coupling to simulate the effect of a spin dependent magnetic field,in attempt to realize novel spin phases of matter. This effect has been proposed to realize systems consisting of unpaired Dirac cones that are helical, meaning their direction of propagation is tied to the electron spin itself, which are forbidden to exist in graphene or bismuth. The experimental existence of topological order can not be determined without spin-resolved measurements. Here we report a spin-and angle-resolved photoemission study of the hexagonal surface of the Bi2Te3 and Bi{2-x}MnxTe3 series, which is found to exhibit a single helical Dirac cone that is fully spin-polarized. Our observations of a gap in the bulk spin-degenerate band and a spin-resolved surface Dirac node close to the chemical potential show that the low energy dynamics of Bi2Te3 is dominated by the unpaired spin-helical Dirac modes. Our spin-texture measurements prove the existence of a rare topological phase in this materials class for the first time, and suggest its suitability for novel 2D Dirac spin device applications beyond the chiral variety or traditional graphene.Comment: 13 pages, 4 figure

Scaling properties of three-dimensional magnetohydrodynamic turbulence

The scaling properties of three-dimensional magnetohydrodynamic turbulence are obtained from direct numerical simulations of decaying turbulence using $512^3$ modes. The results indicate that the turbulence does not follow the Iroshnikov-Kraichnan phenomenology.In the case of hyperresistivity, the structure functions exhibit a clear scaling range yielding absolute values of the scaling exponents $\zeta_p$. The scaling exponents agree with a modified She-Leveque model $\zeta_p=p/9 + 1 - (1/3)^{p/3}$, corresponding to Kolmogorov scaling but sheet-like geometry of the dissipative structures

Abell 41: shaping of a planetary nebula by a binary central star?

We present the first detailed spatio-kinematical analysis and modelling of the planetary nebula Abell 41, which is known to contain the well-studied close-binary system MT Ser. This object represents an important test case in the study of the evolution of planetary nebulae with binary central stars as current evolutionary theories predict that the binary plane should be aligned perpendicular to the symmetry axis of the nebula. Deep narrowband imaging in the light of [NII], [OIII] and [SII], obtained using ACAM on the William Herschel Telescope, has been used to investigate the ionisation structure of Abell 41. Longslit observations of the H-alpha and [NII] emission were obtained using the Manchester Echelle Spectrometer on the 2.1-m San Pedro M\'artir Telescope. These spectra, combined with the narrowband imagery, were used to develop a spatio-kinematical model of [NII] emission from Abell 41. The best fitting model reveals Abell 41 to have a waisted, bipolar structure with an expansion velocity of ~40km\s at the waist. The symmetry axis of the model nebula is within 5\degr of perpendicular to the orbital plane of the central binary system. This provides strong evidence that the close-binary system, MT Ser, has directly affected the shaping of its nebula, Abell 41. Although the theoretical link between bipolar planetary nebulae and binary central stars is long established, this nebula is only the second to have this link, between nebular symmetry axis and binary plane, proved observationally.Comment: 7 pages, 6 figures, Accepted for publication in MNRA

Kinks in the Presence of Rapidly Varying Perturbations

Dynamics of sine-Gordon kinks in the presence of rapidly varying periodic perturbations of different physical origins is described analytically and numerically. The analytical approach is based on asymptotic expansions, and it allows to derive, in a rigorous way, an effective nonlinear equation for the slowly varying field component in any order of the asymptotic procedure as expansions in the small parameter $\omega^{-1}$, $\omega$ being the frequency of the rapidly varying ac driving force. Three physically important examples of such a dynamics, {\em i.e.}, kinks driven by a direct or parametric ac force, and kinks on rotating and oscillating background, are analysed in detail. It is shown that in the main order of the asymptotic procedure the effective equation for the slowly varying field component is {\em a renormalized sine-Gordon equation} in the case of the direct driving force or rotating (but phase-locked to an external ac force) background, and it is {\em the double sine-Gordon equation} for the parametric driving force. The properties of the kinks described by the renormalized nonlinear equations are analysed, and it is demonstrated analytically and numerically which kinds of physical phenomena may be expected in dealing with the renormalized, rather than the unrenormalized, nonlinear dynamics. In particular, we predict several qualitatively new effects which include, {\em e.g.}, the perturbation-inducedComment: New copy of the paper of the above title to replace the previous one, lost in the midst of the bulletin board. RevTeX 3.

Fluorescence resonance energy transfer between organic dyes adsorbed onto nano-clay and Langmuir-Blodgett (LB) films

In this communication we investigate two dyes N,N' -dioctadecyl thiacyanine perchlorate (NK) and octadecyl rhodamine B chloride (RhB) in Langmuir and Langmuir-Blodgett (LB) films with or with out a synthetic clay laponite. Observed changes in isotherms of RhB in absence and presence of nano-clay platelets indicate the incorporation of clay platelets onto RhB-clay hybrid films. AFM image confirms the incorporation of clay in hybrid films. FRET was observed in clay dispersion and LB films with and without clay. Efficiency of energy transfer was maximum in LB films with clay.Comment: 15 pages 5 figures, 1 tabl