On the structure of split Lie color algebras

AbstractThe class of Lie color algebras contains the one of Lie superalgebras and so the one of Lie algebras. In order to begin an approach to the structure of arbitrary Lie color algebras, (with no restrictions neither on the dimension nor on the base field), we introduce the class of split Lie color algebras as the natural extension of the classes of split Lie algebras and split Lie superalgebras. By developing techniques of connections of roots for this kind of algebra, we show that any such algebra L is of the form L=U+∑jIj with U a subspace of the abelian (graded) subalgebra H and eachx Ij a well described (graded) ideal of L satisfying [Ij,Ik]=0 if j≠k. Under certain conditions, the simplicity of L is characterized and it is shown that L is the direct sum of the family of its minimal (graded) ideals, each one being a simple split Lie color algebra

Distributed Real-Time Computation of the Point of Gaze

This paper presents a minimally intrusive real-time gaze-tracking prototype to be used in several scenarios, including a laboratory stall and an in-vehicle system. The system requires specific infrared illumination to allow it to work with variable light conditions. However, it is minimally intrusive due to the use of a carefully configured switched infrared LED array. Although the perceived level of illumination generated by this array is high, it is achieved using low-emission infrared light beams. Accuracy is achieved through a precise estimate of the center of the user's pupil. To overcome inherent time restrictions while using low-cost processors, its main image-processing algorithm has been distributed over four main computing tasks. This structure not only enables good performance, but also simplifies the task of experimenting with alternative computationally-complex algorithms and with alternative tracking models based on locating both user eyes and several cameras to improve user mobility

The Stellar 72Ge(n, γ) Cross Section for weak s-process: A First Measurement at n_TOF

In line with the principles that apply to scientific publishing and the CERN policy in matters of scientific publications, the n_TOF Collaboration recognises the work of V. Furman and P. Sedyshev (JINR, Russia), who have contributed to the experiment used to obtain the results described in this paper. This work was supported by the European Research Council ERC-2015-STG Nr. 677497, the Austrian Science Fund FWF (J 3503), the Science and Technology Facilities Council UK (ST/M006085/1), the Adolf Messer Foundation, the Croatian Science Foundation under the project 8570, the MSMT of the Czech Republic, the Charles University UNCE/SCI/013 project and by the funding agencies of the participating institutes.The slow neutron capture process (s-process) is responsible for producing about half of the elemental abundances heavier than iron in the universe. Neutron capture cross sections on stable isotopes are a key nuclear physics input for s-process studies. The Ge-72(n, gamma) Maxwellian-Averaged Cross Section (MACS) has an important influence on the production of isotopes between Ge and Zr in the weak s-process in massive stars and so far only theoretical estimations are available. An experiment was carried out at the neutron time-of-flight facility n_TOF at CERN to measure the Ge-72(n, gamma) reaction for the first time at stellar neutron energies. The capture measurement was performed using an enriched (GeO2)-Ge-72 sample at a flight path length of 184 m, which provided high neutron energy resolution. The prompt gamma rays produced after neutron capture were detected with a set of liquid scintillation detectors (C6D6). The neutron capture yield is derived from the counting spectra taking into account the neutron flux and the gamma-ray detection efficiency using the Pulse Height Weighting Technique. Over 70 new neutron resonances were identified, providing an improved resolved reaction cross section to calculate experimental MACS values for the first time. The experiment, data analysis and the new MACS results will be presented including their impact on stellar nucleosynthesis, which was investigated using the post-processing nucleosynthesis code mppnp for a 25 solar mass model.European Research Council (ERC) Spanish Government 677497Austrian Science Fund (FWF) J 3503UK Research & Innovation (UKRI) Science & Technology Facilities Council (STFC) ST/M006085/1Adolf Messer FoundationCroatian Science Foundation 8570Ministry of Education, Youth & Sports - Czech RepublicCharles University UNCE/SCI/01

Preliminary results on the 233U capture cross section and alpha ratio measured at n_TOF (CERN) with the fission tagging technique

233U is of key importance among the fissile nuclei in the Th-U fuel cycle. A particularity of 233U is its small neutron capture cross-section, which is on average about one order of magnitude lower than the fission cross-section. The accuracy in the measurement of the 233U capture cross-section depends crucially on an efficient capture-fission discrimination, thus a combined set-up of fission and γ-detectors is needed. A measurement of the 233U capture cross-section and capture-to-fission ratio was performed at the CERN n_TOF facility. The Total Absorption Calorimeter (TAC) of n_TOF was employed as γ-detector coupled with a novel compact ionization chamber as fission detector. A brief description of the experimental set-up will be given, and essential parts of the analysis procedure as well as the preliminary response of the set-up to capture are presented and discussed