The primary cosmic ray mass composition at energies above 10(14) eV

It is shown in this paper that the experimental data on extensive air showers at the energy interval 10 to the 15th power - 10 to the 17th power eV seems to be described best if it is assumed that the Galactic cosmic rays are described by some sort of a two component picture. The first component is of a mixed composition similar to that at lower energies and the second is dominated by protons. Overall spectrum starts to be enriched in protons at energies about 10 to the 15th power eV bu the effective mass of the primaries remains constant up to energies around 10 to the 16th power eV. That results from the fact that composition gradually changes from multi-component to mixture of protons and heavies. That picture receives also some sort of support from recent observations of relatively high number of nergetic protons in JACEE and Concorde experiments

Lempel-Ziv Parsing in External Memory

For decades, computing the LZ factorization (or LZ77 parsing) of a string has been a requisite and computationally intensive step in many diverse applications, including text indexing and data compression. Many algorithms for LZ77 parsing have been discovered over the years; however, despite the increasing need to apply LZ77 to massive data sets, no algorithm to date scales to inputs that exceed the size of internal memory. In this paper we describe the first algorithm for computing the LZ77 parsing in external memory. Our algorithm is fast in practice and will allow the next generation of text indexes to be realised for massive strings and string collections.Comment: 10 page

Is the primary energy spectrum around the 'knee' a statistical game?

The present state of research of the shape of the energy spectrum of primary cosmic ray nuclei and the chemical composition in the region of the socalled, “knee”, and beyond is highly unsatisfactory. We are not very successful when using extensive air showers. In the present paper an attempt is made to explain what is the cause of such a situation. The experimental results as to which there is no doubt that they were wrongly interpreted, will be indicated

Empirical description of the hadron-hadron and hadron-nucleus interaction at the accelerator energy range

Taking into account several assumptions, a formula is transformed into two expressions for kaon and baryon plus antibaryon production in proton interaction and for pion production in pion interactions. Combining both formulae, expression are obtained for the spectrum of kaons and baryons plus antibaryons produced in the meson interactions. For analysis of the cosmic ray propagation in the atmosphere in actual fact, instead of the formulae for interactions of protons and mesons with protons, formulae appropriate for interactions with air nuclei was used. Using the method outlined among others by Elias et al. (1980) simple corrections were introduced to the derived expressions to account for the fact that the target is an air nucleus

Test of high-energy hadronic interaction models with high-altitude cosmic-ray data

Emulsion experiments placed at high mountain altitudes register hadrons and high-energy γ-rays with an energy threshold in the TeV region. These secondary shower particles are produced in the forward direction of interactions of mainly primary protons and alpha-particles in the Earth’s atmosphere. Single γ’s and hadrons are mainly produced by the interactions of the primary cosmic-ray nuclei of primary energy below 1015 eV. Therefore the measurements are sensitive to the physics of high-energy hadronic interaction models, e.g., as implemented in the Monte Carlo air shower simulation program CORSIKA. By use of detailed simulations invoking various different models for the hadronic interactions we compare the predictions for the single-particle spectra with data of the Pamir experiment. For higher primary energies characteristics of so-called gamma-ray families are used for the comparisons. Including detailed simulations for the Pamir detector we found that the data are incompatible with the HDPM and SIBYLL 1.6 models, but are in agreement with QGSJET, neXus, and VENUS

Central mode and soft mode behavior in PbMg1/Nb2/3O3 relaxor ferroelectric

The relaxor ferroelectric PbMg1/Nb2/3O3 was investigated by means of broad-band dielectric and Fourier Transform Infrared (FTIR) transmission spectroscopy in the frequency range from 1 MHz to 15 THz at temperatures between 20 and 900 K using PMN films on infrared transparent sapphire substrates. While thin film relaxors display reduced dielectric permittivity at low frequencies, their high frequency intrinsic or lattice response is shown to be the same as single crystal/ceramic specemins. It was observed that in contrast to the results of inelastic neutron scattering, the optic soft mode was underdamped at all temperatures. On heating, the TO1 soft phonon followed the Cochran law with an extrapolated critical temperature equal to the Burns temperature of 670 K and softened down to 50 cm-1. Above 450 K the soft mode frequency leveled off and slightly increased above the Burns temperature. A central mode, describing the dynamics of polar nanoclusters appeared below the Burns temperature at frequencies near the optic soft mode and dramatically slowed down below 1 MHz on cooling below room temperature. It broadened on cooling, giving rise to frequency independent losses in microwave and lower frequency range below the freezing temperature of 200 K. In addition, a new heavily damped mode appeared in the FTIR spectra below the soft mode frequency at room temperature and below. The origin of this mode as well as the discrepancy between the soft mode damping in neutron and infrared spectra is discussed.Comment: 7 pages with 7 figures, submitted to Phys. Rev.

Improved superlensing in two-dimensional photonic crystals with a basis

We study propagation of light in square and hexagonal two-dimensional photonic crystals. We show, that slabs of these crystals focus light with subwavelength resolution. We propose a systematic way to increase this resolution, at an essentially fixed frequency, by employing a hierarchy of crystals of the same structure, and the same lattice constant, but with an increasingly complex basis.Comment: 16 Pages, 5 Figure

School Self Evaluation Concepts in The Context of Program Evaluation Mobile School

Evaluation of the driving school program is important in proving the success or failure of the program. The stages in the evaluation of driving schools consist of the initial program evaluation stage, the mid-program stage and the final program stage. Driving schools must prepare themselves to face the evaluation process according to the intended stages. Self-evaluation is one of the alternative choices that schools can make to assess the school's self-assessment in achieving the driving school program in order to take steps to change on an ongoing basis in order to achieve the goals of the driving school program as stipulated. This research is a descriptive research carried out using the library research method using content analysis (content analysis). Based on information obtained from the literature related to the concept of school self-evaluation, program evaluation and school performance according to the results of the analysis, school institutions through the concept of self-evaluation with an action research approach can be carried out through the stages of preparation, data collection, formulation of evaluation results, planning and implementing change plans . School self-evaluation with this approach can be carried out repeatedly so that significant changes can be made in order to realize improvements so that the results and impact of the driving school program can be felt