2,617 research outputs found

    Safflower Production in the Western Part of the Northern Great Plains

    Get PDF
    Recent development of new varieties with seeds averaging more than 30 per cent oil give safflower a good chance of becoming an important oil seed crop in the United States. It is the purpose of this circular to acquaint farmers with the crop and to outline the most promising production practices for those who undertake its production in the western part of the northern Great Plains

    Low temperature acoustic properties of amorphous silica and the Tunneling Model

    Full text link
    Internal friction and speed of sound of a-SiO(2) was measured above 6 mK using a torsional oscillator at 90 kHz, controlling for thermal decoupling, non-linear effects, and clamping losses. Strain amplitudes e(A) = 10^{-8} mark the transition between the linear and non-linear regime. In the linear regime, excellent agreement with the Tunneling Model was observed for both the internal friction and speed of sound, with a cut-off energy of E(min) = 6.6 mK. In the non-linear regime, two different behaviors were observed. Above 10 mK the behavior was typical for non-linear harmonic oscillators, while below 10 mK a different behavior was found. Its origin is not understood.Comment: 1 tex file, 6 figure

    Modeling of field singularities at dielectric edges using grid based methods

    Get PDF
    Electric field singularities at sharp metallic edges or at a dielectric contact line can be described analytically by asymptotic expressions. The a priori known form of the field distribution in the vicinity of these edges can be used to construct numerical methods with improved accuracy. This contribution focuses on a modified Finite Integration Technique and on a Discontinuous Galerkin Method with singular approximation functions. Both methods are able to handle field singularities at perfectly electric conducting as well as at dielectric edges. The numerical accuracy of these methods is investigated in a number of simulation examples including static and dynamic field problems

    Coherent theta oscillations in the cerebellum and supplementary motor area mediate visuomotor adaptation

    Get PDF
    The cerebellum and its interaction with cortical areas play a key role in our ability to flexibly adapt a motor program in response to sensory input. Current knowledge about specific neural mechanisms underlying the process of visuomotor adaptation is however lacking. Using a novel placement of EEG electrodes to record electric activity from the cerebellum, we studied local cerebellar activity, as well as its coupling with neocortical activity to obtain direct neurophysiological markers of visuomotor adaptation in humans. We found increased theta (4-8 Hz) power in "cerebellar" as well as cortical electrodes, when subjects first encountered a visual manipulation. Theta power decreased as subjects adapted to the perturbation, and rebounded when the manipulation was suddenly removed. This effect was observed in two distinct locations: a cerebellar cluster and a central cluster, which were localized in left cerebellar crus I (lCB) and right supplementary motor area (rSMA) using linear constrained minimum variance beamforming. Importantly, we found that better adaptation was associated with increased theta power in left cerebellar electrodes and a right sensorimotor cortex electrode. Finally, increased rSMA -> lCB connectivity was significantly decreased with adaptation. These results demonstrate that: (1) cerebellar theta power is markedly modulated over the course of visuomotor adaptation and (2) theta oscillations could serve as a key mechanism for communication within a cortico-cerebellar loop

    Plant genotype, not nutrients, shape aphid population dynamics

    Get PDF

    2D electron cyclotron emission imaging at ASDEX Upgrade (invited)

    Get PDF
    The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfvén eigenmode, showing both the advantage of having a two-dimensional 2D measurement, as well as some of the limitations of electron cyclotron emission measurements. Furthermore, the application of singular value decomposition as a powerful tool for analyzing and filtering 2D data is presented. © 2010 American Institute of Physics

    The impact of infrared beak treatment on turkey tom and hen beak length and performance to 12 weeks of age

    Get PDF
    Controlling injurious pecking in commercial turkeys remains a significant challenge to producers and the industry. Infrared beak treatment is an effective method of controlling injurious pecking in chickens; however, the effects of infrared beak treatment on turkey performance are still largely unknown. Two experiments were conducted to determine the impact of infrared beak treatment on the beak length and performance of turkeys raised to 12 wk of age. Experiment 1 tested both toms (n = 236) and hens (n = 324), while Experiment 2 focused on hens (n = 608). Poults for each experiment were assigned to 1 of 2 beak treatments: infrared beak treated (IR) on the day of hatch at a commercial hatchery or sham untreated control (C). Data collected included beak length, body weight, feed intake, feed efficiency, and mortality. Data were analyzed using a 1 or 2-way ANOVA, followed by Tukey's range test for mean separation when interactions were found. Results showed that beak length (Experiment 1 only) was significantly shorter in IR poults from 2 to 12 wk of age. In the same experiment, IR toms had lighter body weight than C toms, but IR hens were heavier than C hens from 2 to 4 wk of age. By 12 wk, IR poults were heavier than C poults, regardless of gender. In experiment 2, IR hens had lighter body weight from 2 to 4 wk of age. In conclusion, infrared beak treatment had minimal effects on feed intake, feed efficiency, or mortality over the 12-wk periods of both experiments

    Path integral Monte Carlo simulation of helium at negative pressures

    Full text link
    Path integral Monte Carlo (PIMC) simulations of liquid helium at negative pressure have been carried out for a temperature range from the critical temperature to below the superfluid transition. We have calculated the temperature dependence of the spinodal line as well as the pressure dependence of the isothermal sound velocity in the region of the spinodal. We discuss the slope of the superfluid transition line and the shape of the dispersion curve at negative pressures.Comment: 6 pages, 7 figures, submitted to Physical Review B Revised: new reference, replaced figure
    corecore