12 research outputs found
Geographical Affinities among Human Populations from Wales and from Regions in North and Central England on the Basis of Epidermal Ridge Markers. A Discriminant Function Approach
Discriminant function analysis of dermatoglyphic variables for seven regions in Wales, North and Central England has disclosed geographical affinities between adjacent populations. The results are consistent for two distinct variable sets and for the sexes, whereas univariate comparisons failed to reveal much in the way of differences or geographical trends. The significance of these observations is discussed in relationship to greater variation which has been identified at more local scales in the British Isles
Inhibition of tyrosine kinase receptor type B synthesis blocks axogenic effect of estradiol on rat hypothalamic neurones in vitro
MODIFICATION BY DILTIAZEM, A CALCIUM ANTAGONIST, OF THE PULMONARY VAGAL AND CARDIAC SYMPATHETIC CHEMOREFLEXES IN THE DOG
Valaciclovir for the suppression of recurrent genital HSV infection: a placebo controlled study of once daily therapy. International Valaciclovir HSV Study Group.
Evolution of a plasma column measured through modulation of a high-energy proton beam
Plasma wakefield acceleration is a method for accelerating particle beams using electromagnetic fields that are orders of magnitude larger than those found in conventional radio frequency cavities. The core component of a plasma wakefield accelerator is the plasma source, which ranges from millimeter-scale gas jets used in laser-driven experiments, to the ten-meter-long rubidium cell used in the AWAKE experiment. The density of the neutral gas is a controlled input to the experiment, but the density of the plasma after ionization depends on many factors. AWAKE uses a high-energy proton beam to drive the plasma wakefield, and the wakefield acts back on the proton bunch by modulating it at the plasma frequency. We infer the plasma density by measuring the frequency of modulation of the proton bunch, and we measure the evolution of the density versus time by varying the arrival of the proton beam with respect to the ionizing laser pulse. Using this technique, we uncover a microsecond-long period of a stable plasma density followed by a rapid decay in density. The stability of the plasma after ionization has implications for the design of much longer vapor cells that could be used to accelerate particle beams to extremely high energies
Proton beam defocusing in AWAKE: comparison of simulations and measurements
In 2017, AWAKE demonstrated the seeded self-modulation (SSM) of a 400 GeV proton beam from the Super Proton Synchrotron (SPS) at CERN. The angular distribution of the protons deflected due to SSM is a quantitative measure of the process, which agrees with simulations by the two-dimensional (axisymmetric) particle-in-cell code LCODE. Agreement is achieved for beam populations between and particles, various plasma density gradients () and two plasma densities ( and ). The agreement is reached only in the case of a wide enough simulation box (at least five plasma wavelengths)