3,076 research outputs found

    High resolution power spectra of daily Zurich sunspot numbers

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    High resolution power spectra of 77 years of Zurich daily sunspot numbers were computed using various lags and data point intervals. Major harmonic peaks of the approximately 124-month period showed up strongly as well as the 27-day solar rotational period

    On differential equations invariant under two-variable Moebius transformations

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    We compute invariants for the two-variable M ̈obius transformation. In particular we are interested in partial differential equations in two dependent and two independent variables that are kept invariant under this transformation

    A proof of Jarzynski's non-equilibrium work theorem for dynamical systems that conserve the canonical distribution

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    We present a derivation of the Jarzynski identity and the Crooks fluctuation theorem for systems governed by deterministic dynamics that conserves the canonical distribution such as Hamiltonian dynamics, Nose-Hoover dynamics, Nose-Hoover chains and Gaussian isokinetic dynamics. The proof is based on a relation between the heat absorbed by the system during the non-equilibrium process and the Jacobian of the phase flow generated by the dynamics.Comment: 12 page

    Drinking Gall and Vinegar: Psalm 69:22: An Underestimated Intertext in Matt 27:34, 48

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    The intertextual play with Psalm 69:22 in Matt 27:34, 48 is an important aspect for adequately understanding Matthew’s crucifixion scene. In Matt 27:34 the Roman soldiers offer Jesus “wine mixed with gall”, which is an allusion to Psalm 69:22a. By acting as the praying-self’s opponents, the Roman soldiers are portrayed as the mockers of Psalm 69:22a. In Matt 27:48, the Jewish authorities offer vinegar to the crucified Jesus, which is a clear allusion to Psalm 69:22b. Therefore, the Jewish authorities are portrayed in parallel to the Roman soldiers. Considering that Matthew refers to Psalm 69:22 not in a selective manner, but in the psalm’s context, the parallel between the Roman soldiers and the Jewish authorities extends to the crucial point in Jewish self-conception of being accused of áŒ€ÎœÎżÎŒÎŻÎ±

    A Nonliearly Dispersive Fifth Order Integrable Equation and its Hierarchy

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    In this paper, we study the properties of a nonlinearly dispersive integrable system of fifth order and its associated hierarchy. We describe a Lax representation for such a system which leads to two infinite series of conserved charges and two hierarchies of equations that share the same conserved charges. We construct two compatible Hamiltonian structures as well as their Casimir functionals. One of the structures has a single Casimir functional while the other has two. This allows us to extend the flows into negative order and clarifies the meaning of two different hierarchies of positive flows. We study the behavior of these systems under a hodograph transformation and show that they are related to the Kaup-Kupershmidt and the Sawada-Kotera equations under appropriate Miura transformations. We also discuss briefly some properties associated with the generalization of second, third and fourth order Lax operators.Comment: 11 pages, LaTex, version to be published in Journal of Nonlinear Mathematical Physics, has expanded discussio

    The Puzzle of the Flyby Anomaly

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    Close planetary flybys are frequently employed as a technique to place spacecraft on extreme solar system trajectories that would otherwise require much larger booster vehicles or may not even be feasible when relying solely on chemical propulsion. The theoretical description of the flybys, referred to as gravity assists, is well established. However, there seems to be a lack of understanding of the physical processes occurring during these dynamical events. Radio-metric tracking data received from a number of spacecraft that experienced an Earth gravity assist indicate the presence of an unexpected energy change that happened during the flyby and cannot be explained by the standard methods of modern astrodynamics. This puzzling behavior of several spacecraft has become known as the flyby anomaly. We present the summary of the recent anomalous observations and discuss possible ways to resolve this puzzle.Comment: 6 pages, 1 figure. Accepted for publication by Space Science Review

    Thermal conductance of thin film YIG determined using Bayesian statistics

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    Thin film YIG (Y3_3Fe5_5O12_{12}) is a prototypical material for experiments on thermally generated pure spin currents and the spin Seebeck effect. The 3-omega method is an established technique to measure the cross-plane thermal conductance of thin films, but can not be used in YIG/GGG (Ga3_3Gd5_5O12_{12}) systems in its standard form. We use two-dimensional modeling of heat transport and introduce a technique based on Bayesian statistics to evaluate measurement data taken from the 3-omega method. Our analysis method allows us to study materials systems that have not been accessible with the conventionally used 3-omega analysis. Temperature dependent thermal conductance data of thin film YIG are of major importance for experiments in the field of spin-caloritronics. Here we show data between room temperature and 10 K for films covering a wide thickness range as well as the magnetic field effect on the thermal conductance between 10 K and 50 K

    Florística e fitossociologia em åreas de manejo de açaizais no estuårio amazÎnico.

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    Este estudo teve como objetivo analisar a composição florĂ­stica e a fitossociologia em trĂȘs regiĂ”es do estuĂĄrio amazĂŽnico em que Ă© praticado o manejo de açaizais nativos. Nas regiĂ”es foram instaladas 30 parcelas de 0,5 ha e amostradas todas as espĂ©cies arbĂłreas e palmeiras com DAP ? 5 cm, mediu-se tambĂ©m a circunferĂȘncia a altura do peito (CAP) com fita mĂ©trica de precisĂŁo de 1mm. Foram inventariados 10821 indivĂ­duos, representados por 114 espĂ©cies, 96 gĂȘneros e 33 famĂ­lias. As famĂ­lias mais representativas foram Arecaceae (9 espĂ©cies e 8007 indivĂ­duos), seguida por Rubiaceae (2 espĂ©cies e 522 indivĂ­duos),Myristicaceae (1 espĂ©cie e 268 indivĂ­duos), Malvaceae (10 espĂ©cies e 264 indivĂ­duos) e Euphorbiaceae (4 espĂ©cies e 247 indivĂ­duos). Constatou-se que a riqueza nas ĂĄreas de manejo inventariadas permaneceu alta apesar da pressĂŁo antrĂłpica que essas ĂĄreas sofrem
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