Analysis of the electron component of EAS at observational level 700 g x cm(-2) with a scale breaking interaction model and gammaisation hypothesis

Scale breaking model and gammaisation processes for high energies give a correct description of the longitudinal development of extensive air showers (E.A.S.). From the analysis of phenomenological characteristics of E.A.S. at Tien-Shan experiment, it follows that for energies near 10 to the 6 GeV the secondary particle multiplicity increases with energy faster than is predicted by the accepted scale breaking model

Bi(2223) Ag sheathed tape Ic and exponent n characterisation and modelling under DC applied magnetic field

We use a dual channel digital lock-in to perform electrical measurement of AC losses at power frequencies. A DC magnetic field between 2 and 400 mT is applied with a varying angle from parallel to perpendicular to the tape surface, thus having a complete view of the loss behavior under DC applied field. Furthermore, the same experimental layout is used to acquire time series of current and voltage across the sample. Using a triangular input current, we measure and average the voltage, which then is fitted to a power law (I/Ic)^n. The measurements are repeated for the mentioned magnetic field and angle domain to give the dependencies of Ic and n with magnetic field and angle. For device modeling purposes, we can then express a phenomenological law giving Ic and n as a function of the applied magnetic field's intensity and direction

A Catalog of Very Isolated Galaxies from the SDSS Data Release 1

We present a new catalog of isolated galaxies obtained through an automated systematic search. These 2980 isolated galaxies were found in approximately 2099 sq deg of sky in the Sloan Digital Sky Survey Data Release 1 (SDSS DR1) photometry. The selection algorithm, implementing a variation on the criteria developed by Karachentseva in 1973, proved to be very efficient and fast. This catalog will be useful for studies of the general galaxy characteristics. Here we report on our results.Comment: 67 pages, which includes 14 figures. Accepted for publication by A

The Low-Redshift Lyman Alpha Forest toward PKS 0405-123

We present STIS 7km/s resolution data of the Ly-a forest toward PKS0405-123 (z=0.574). We make two samples. The strong sample (60 systems) has column density logNHI>13.3 over 0.002<z<0.423, and the weak sample (44) has logNHI>13.1 at 0.020<z<0.234; 7 absorbers show metals, all with OVI, but often offset in velocity from HI. The strong sample Doppler parameters show =47+-22km/s; for the weak, =44+-21km/s. Line blending and s/n effects likely inflate b. The redshift density dN/dz is consistent with previous, lower resolution results for logNHI>14.0. For 13.1<logNHI<14.0, we find a dN/dz overdensity of ~0.2-0.3 dex at 0.127<z<0.234, which we believe arises from cosmic variance. We find Ly-a clustering over Delta v13.3, consistent with a numerical model. There is a void in the strong sample at 0.0320<z<0.0814. We detect radial velocity correlations for Delta v<250km/s between Ly-a absorbers and 39 galaxies in a 10' field. The correlation grows with minimum NHI, peaking for logNHI ~> 13.5-14.0. The strength is similar to that of the galaxy-galaxy correlation for our sample, implying that such Ly-a systems have mass log M/Msun= 11.3+1.0-0.6. Including lower column density systems in the sample shows correlations only out to Delta v <125km/s, as would be expected for smaller density perturbations. Galaxy counts and local HI column density appear correlated, peaking at ~5000km/s. We also give column densities for Galactic species. (Abridged)Comment: 59 pages, 6 tables, 14 figures, 1 standalone, ApJ, in press; minor revisions/clarifications for acceptance, including galaxy lis

IsoBED: a tool for automatic calculation of biologically equivalent fractionation schedules in radiotherapy using IMRT with a simultaneous integrated boost (SIB) technique

<p>Abstract</p> <p>Background</p> <p>An advantage of the Intensity Modulated Radiotherapy (IMRT) technique is the feasibility to deliver different therapeutic dose levels to PTVs in a single treatment session using the Simultaneous Integrated Boost (SIB) technique. The paper aims to describe an automated tool to calculate the dose to be delivered with the SIB-IMRT technique in different anatomical regions that have the same Biological Equivalent Dose (BED), i.e. IsoBED, compared to the standard fractionation.</p> <p>Methods</p> <p>Based on the Linear Quadratic Model (LQM), we developed software that allows treatment schedules, biologically equivalent to standard fractionations, to be calculated. The main radiobiological parameters from literature are included in a database inside the software, which can be updated according to the clinical experience of each Institute. In particular, the BED to each target volume will be computed based on the alpha/beta ratio, total dose and the dose per fraction (generally 2 Gy for a standard fractionation). Then, after selecting the reference target, i.e. the PTV that controls the fractionation, a new total dose and dose per fraction providing the same isoBED will be calculated for each target volume.</p> <p>Results</p> <p>The IsoBED Software developed allows: 1) the calculation of new IsoBED treatment schedules derived from standard prescriptions and based on LQM, 2) the conversion of the dose-volume histograms (DVHs) for each Target and OAR to a nominal standard dose at 2Gy per fraction in order to be shown together with the DV-constraints from literature, based on the LQM and radiobiological parameters, and 3) the calculation of Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP) curve versus the prescribed dose to the reference target.</p

Geometry considerations for transport current applications of Bi-2223 conductors with anisotropic Jc(B) in external magnetic field

In certain power applications, Bi-2223 conductors carrying AC current will be subjected to external magnetic fields, whose orientation and conductor’s geometry are of major significance for the AC loss magnitude. This paper investigates the influence of the geometry and aspect ratio of non-twisted Bi-2223 conductors in reducing the AC loss for such applications. A numerical model of high-Tc materials has been used in FEM simulations. The model incorporates power-law E-J characteristics with Jc defined by both parallel and perpendicular local magnetic field components. It allows computations of field and current distributions with transport current and/or applied field of any orientation. Monofilamentary tapes of rectangular and elliptical geometry with anisotropic Jc(B), as well as square and round wires with isotropic Jc(B) have been used for simulations under various operating conditions. A comparison between AC losses, magnetic field and current distributions in the tapes and wires is presented. It is demonstrated that depending on the orientation of the external field the difference of AC losses for non-twisted conductors with different geometry may reach one order of magnitude