4,082 research outputs found

    Plant pathogenic bacteria

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    Protein Inhibitors of Calcium Salt Crystal Growth in Saliva, Bile and Pancreatic Juice

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    The control of the formation of crystals in biological fluids is one of the most exciting field of research involving both organic and biochemical areas. Many organisms have evolved mechanisms which minimize or avoid the effects of nucleation and crystal growth formation. One of the most important mechanism is the interaction of specific proteins, called inhibitors, with crystals which alters their habits and leads to their elimination. This article, focused on saliva, pancreatic juice and bile, reviews our present knowledge on the structure-function relationships existing between these proteins and their ability to inhibit the growth of different calcium salt crystals

    Sound and light from fractures in scintillators

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    Prompted by intriguing events observed in certain particle-physics searches for rare events, we study light and acoustic emission simultaneously in some inorganic scintillators subject to mechanical stress. We observe mechanoluminescence in Bi4Ge3O12{Bi}_4{Ge}_{3}{O}_{12}, CdWO4{CdWO}_{4} and ZnWO4{ZnWO}_{4}, in various mechanical configurations at room temperature and ambient pressure. We analyze how the light emission is correlated to acoustic emission during fracture. For Bi4Ge3O12{Bi}_4{Ge}_{3}{O}_{12}, we set a lower bound on the energy of the emitted light, and deduce that the fraction of elastic energy converted to light is at least 3×1053 \times 10^{-5}

    Measurement of Resonance Driving Terms from Turn-by-Turn Data

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    It has been shown that the Fourier analysis of recorded turn-by-turn tracking data can be used to derive resonance terms of an accelerator. Besides the resonance driving terms, the non-linear one-turn map can be obtained with all non-linearities arising from magnetic imperfections and correction elements. This could be interesting for the LHC which will be a machine that is dominated by strong non-linear fields. The methods works very well for tracking data and is expected to work equally well for turn-by-turn beam data. The precision to which these terms can be determined relies on the frequency analysis tool. To demonstrate the feasibility of the method, measurements of real accelerators are presented in which the beam is kicked once and the beam oscillations are recorded over several thousand turns. Besides the tune, the strengths of resonance driving terms have been measured and the results are compared with numerical calculation

    Interface relaxation in electrophoretic deposition of polymer chains: Effects of segmental dynamics, molecular weight, and field

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    Using different segmental dynamics and relaxation, characteristics of the interface growth is examined in an electrophoretic deposition of polymer chains on a three (2+1) dimensional discrete lattice with a Monte Carlo simulation. Incorporation of faster modes such as crankshaft and reptation movements along with the relatively slow kink-jump dynamics seems crucial in relaxing the interface width. As the continuously released polymer chains are driven (via segmental movements) and deposited, the interface width WW grows with the number of time steps tt, Wtβ,W \propto t^{\beta}, (β0.4\beta \sim 0.4--0.8)0.8), which is followed by its saturation to a steady-state value WsW_s. Stopping the release of additional chains after saturation while continuing the segmental movements relaxes the saturated width to an equilibrium value (WsWrW_s \to W_r). Scaling of the relaxed interface width WrW_r with the driving field EE, WrE1/2W_r \propto E^{-1/2} remains similar to that of the steady-state WsW_s width. In contrast to monotonic increase of the steady-state width WsW_s, the relaxed interface width WrW_r is found to decay (possibly as a stretched exponential) with the molecular weight.Comment: 5 pages, 7 figure

    Droplet actuation induced by coalescence: experimental evidences and phenomenological modeling

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    This paper considers the interaction between two droplets placed on a substrate in immediate vicinity. We show here that when the two droplets are of different fluids and especially when one of the droplet is highly volatile, a wealth of fascinating phenomena can be observed. In particular, the interaction may result in the actuation of the droplet system, i.e. its displacement over a finite length. In order to control this displacement, we consider droplets confined on a hydrophilic stripe created by plasma-treating a PDMS substrate. This controlled actuation opens up unexplored opportunities in the field of microfluidics. In order to explain the observed actuation phenomenon, we propose a simple phenomenological model based on Newton's second law and a simple balance between the driving force arising from surface energy gradients and the viscous resistive force. This simple model is able to reproduce qualitatively and quantitatively the observed droplet dynamics

    Higgs to mu tau Decay in Supersymmetry without R Parity

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    In this letter, we report on lepton flavor violating Higgs decay into mu+tau in the framework of the generic supersymmetric standard model without R parity and list interesting combinations of R-parity violating parameters. We impose other known experimental constraints on the parameters of the model and show our results from the R-parity violating parameters. In our analysis, the branching ratio of Higgs to mu+tau can exceed 10^{-5} within admissible parameter space.Comment: 16 pages, 3 figures, 1 table. Version published in Europhysics Letter

    Final results of the EDELWEISS-II WIMP search using a 4-kg array of cryogenic germanium detectors with interleaved electrodes

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    The EDELWEISS-II collaboration has completed a direct search for WIMP dark matter with an array of ten 400-g cryogenic germanium detectors in operation at the Laboratoire Souterrain de Modane. The combined use of thermal phonon sensors and charge collection electrodes with an interleaved geometry enables the efficient rejection of gamma-induced radioactivity as well as near-surface interactions. A total effective exposure of 384 kg.d has been achieved, mostly coming from fourteen months of continuous operation. Five nuclear recoil candidates are observed above 20 keV, while the estimated background is 3.0 events. The result is interpreted in terms of limits on the cross-section of spin-independent interactions of WIMPs and nucleons. A cross-section of 4.4x10^-8 pb is excluded at 90%CL for a WIMP mass of 85 GeV. New constraints are also set on models where the WIMP-nucleon scattering is inelastic.Comment: 23 pages, 5 figures; matches published versio
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