2,487 research outputs found

    A Second Cell Wall Acid Invertase Gene in Arabidopsis thaliana

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    Asymmetry Function of Interstellar Scintillations of Pulsars

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    A new method for separating intensity variations of a source's radio emission having various physical natures is proposed. The method is based on a joint analysis of the structure function of the intensity variations and the asymmetry function, which is a generalization of the asymmetry coefficient and characterizes the asymmetry of the distribution function of the intensity fluctuations on various scales for the inhomogeneities in the diffractive scintillation pattern. Relationships for the asymmetry function in the cases of a logarithmic normal distribution of the intensity fluctuations and a normal distribution of the field fluctuations are derived. Theoretical relationships and observational data on interstellar scintillations of pulsars (refractive, diffractive, and weak scintillations) are compared. Pulsar scintillations match the behavior expected for a normal distribution of the field fluctuations (diffractive scintillation) or logarithmic normal distribution of the intensity fluctuations (refractive and weak scintillation). Analysis of the asymmetry function is a good test for distinguishing scintillations against the background of variations that have different origins

    Measurement of the electron electric dipole moment using GdIG

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    A new method for the detection of the electron edm using a solid is described. The method involves the measurement of a voltage induced across the solid by the alignment of the samples magnetic dipoles in an applied magnetic field, H. A first application of the method to GdIG has resulted in a limit on the electron edm of 5E-24 e-cm, which is a factor of 40 below the limit obtained from the only previous solid-state edm experiment. The result is limited by the imperfect discrimination of an unexpectedly large voltage that is even upon the reversal of the sample magnetization.Comment: 10 pages, 5 figures, v2:references corrected, submitted to PRL, v3:added labels to figure

    Well-Posedness and Symmetries of Strongly Coupled Network Equations

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    We consider a diffusion process on the edges of a finite network and allow for feedback effects between different, possibly non-adjacent edges. This generalizes the setting that is common in the literature, where the only considered interactions take place at the boundary, i. e., in the nodes of the network. We discuss well-posedness of the associated initial value problem as well as contractivity and positivity properties of its solutions. Finally, we discuss qualitative properties that can be formulated in terms of invariance of linear subspaces of the state space, i. e., of symmetries of the associated physical system. Applications to a neurobiological model as well as to a system of linear Schroedinger equations on a quantum graph are discussed.Comment: 25 pages. Corrected typos and minor change

    Seabeam and seismic reflection imaging of the tectonic regime of the Andean continental margin off Peru (4°S to 10°S)

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    Suite à une campagne géophysique réalisée au large de la côte du Perou (croisière Seaperc du R/V "Jean Charcot", juillet 1986), les auteurs proposent une nouvelle interprétation des structures caractérisant la pente continentale de la région étudiée. D'autre part, ils considèrent que cette marge active est une marge active en extension ou bien une marge d'effondrement qui développe un complexe d'accrétion induit par les effondrements de la partie médiane de la pente

    The PHIN photoinjector for the CTF3 Drive beam

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    A new photoinjector for the CTF3 drive beam has been designed and is now being constructed by a collaboration among LAL, CCLRC and CERN within PHIN, the second Joint Research Activity of CARE. The photoinjector will provide a train of 2332 pulses at 1.5 GHz with a complex timing structure (sub-trains of 212 pulses spaced from one another by 333 ps or 999 ps) to allow the frequency multiplication scheme, which is one of the features of CLIC, to be tested in CTF3. Each pulse of 2.33 nC will be emitted by a Cs2Te photocathode deposited by a co-evaporation process to allow high quantum efficiency in operation (>3% for a minimum of 40 h). The 3 GHz, 2 1/2 cell RF gun has a 2 port coupler to minimize emittance growth due to asymmetric fields, racetrack profile of the irises and two solenoids to keep the emittance at the output below 20 p.mm.mrad. The laser has to survive very high average powers both within the pulse train (15 kW) and overall (200 W before pulse slicing). Challenging targets are also for amplitude stability (<0.25% rms) and time jitter from pulse to pulse (<1ps rms). An offline test in a dedicated line is foreseen at CERN in 2007
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