Measurement of the trailing edge of cosmic-ray track signals from a round-tube drift chamber

The trailing edge of tube drift-chamber signals for charged particles is expected to provide information concerning the particle passage time. This information may be useful for separating meaningful signals from overlapping garbage at high-rate experiments, such as the future LHC experiments. We carried out a cosmic-ray test using a small tube chamber in order to investigate the feasibility of this idea. We achieved a trailing-edge time resolution of 12 ns in rms by applying simple pulse shaping to eliminate a signal tail. A comparison with a Monte Carlo simulation indicates the importance of well-optimized signal shaping to achieve good resolution. The resolution may be further improved with better shaping.Comment: 13 pages including 9 figure

q-deformed dynamics and Josephson junction

We define a generalized rate equation for an observable in quantum mechanics, that involves a parameter q and whose limit $q\to 1$ gives the standard Heisenberg equation. The generalized rate equation is used to study dynamics of current biased Josephson junction. It is observed that this toy model incorporates diffraction like effects in the critical current. Physical interpretation for q is provided which is also shown to be q-deformation parameter.Comment: LaTeX 9 pages, submitted Mod. Phys. Lett. B, e-mail: [email protected]

Dicyema Pax6 and Zic: tool-kit genes in a highly simplified bilaterian

<p>Abstract</p> <p>Background</p> <p>Dicyemid mesozoans (Phylum Dicyemida) are simple (8–40-cell) cephalopod endoparasites. They have neither body cavities nor differentiated organs, such as nervous and gastrointestinal systems. Whether dicyemids are intermediate between Protozoa and Metazoa (as represented by their "Mesozoa" classification) or degenerate species of more complex metazoans is controversial. Recent molecular phylogenetic studies suggested that they are simplified bilaterians belonging to the Lophotrochozoa. We cloned two genes developmentally critical in bilaterian animals (Pax6 and Zic), together with housekeeping genes (actin, fructose-bisphosphate aldolase, and ATP synthase beta subunit) from a dicyemid to reveal whether their molecular phylogeny supported the "simplification" hypothesis, and to clarify evolutionary changes in dicyemid gene structure and expression profiles.</p> <p>Results</p> <p>Genomic/cDNA sequence analysis showed that 1) the Pax6 molecular phylogeny and Zic intron positions supported the idea of dicyemids as reduced bilaterians; 2) the aa sequences deduced from the five genes were highly divergent; and 3) <it>Dicyema </it>genes contained very short introns of uniform length. In situ hybridization analyses revealed that <it>Zic </it>genes were expressed in hermaphroditic gonads, and <it>Pax6 </it>was expressed weakly throughout the developmental stages of the 2 types of embryo and in the hermaphroditic gonads.</p> <p>Conclusion</p> <p>The accelerated evolutionary rates and very short and uniform intron may represent a part of <it>Dicyema </it>genomic features. The presence and expression of the two tool-kit genes (<it>Pax6 </it>and <it>Zic</it>) in <it>Dicyema </it>suggests that they can be very versatile genes even required for the highly reduced bilaterian like <it>Dicyema</it>. Dicyemids may be useful models of evolutionary body plan simplification.</p

Integration of GRACE and PYTHIA

We have successfully developed a technique to integrate an automatic event-generator generation system GRACE and a general-purpose event generator framework PYTHIA. The codes generated by GRACE are embedded in PYTHIA in the created event generator program. The embedded codes give information on parton-level hard interactions directly to PYTHIA. The choice of PDF is controlled by the ordinary parameter setting in PYTHIA. This technique enables us to create easy-to-handle event generators for any processes in hadron collisions. Especially, in virtue of large capability of GRACE, we can easily deal with those processes containing many (four or more) partons in the final state, such as multiple heavy particle productions. This project is being carried out as a collaboration between the Japanese Atlas group and the Minami-Tateya group, aiming at developing event generators for Tevatron and LHC experiments

Fermi-LAT and Suzaku Observations of the Radio Galaxy Centaurus B

Centaurus B is a nearby radio galaxy positioned in the Southern hemisphere close to the Galactic plane. Here we present a detailed analysis of about 43 months of accumulated Fermi-LAT data of the gamma-ray counterpart of the source initially reported in the 2nd Fermi-LAT catalog, and of newly acquired Suzaku X-ray data. We confirm its detection at GeV photon energies, and analyze the extension and variability of the gamma-ray source in the LAT dataset, in which it appears as a steady gamma-ray emitter. The X-ray core of Centaurus B is detected as a bright source of a continuum radiation. We do not detect however any diffuse X-ray emission from the known radio lobes, with the provided upper limit only marginally consistent with the previously claimed ASCA flux. Two scenarios that connect the X-ray and gamma-ray properties are considered. In the first one, we assume that the diffuse non-thermal X-ray emission component is not significantly below the derived Suzaku upper limit. In this case, modeling the inverse-Compton emission shows that the observed gamma-ray flux of the source may in principle be produced within the lobes. This association would imply that efficient in-situ acceleration of the radiating electrons is occurring and that the lobes are dominated by the pressure from the relativistic particles. In the second scenario, with the diffuse X-ray emission well below the Suzaku upper limits, the lobes in the system are instead dominated by the magnetic pressure. In this case, the observed gamma-ray flux is not likely to be produced within the lobes, but instead within the nuclear parts of the jet. By means of synchrotron self-Compton modeling we show that this possibility could be consistent with the broad-band data collected for the unresolved core of Centaurus B, including the newly derived Suzaku spectrum.Comment: Accepted for publication in A&A. 11 page

Densification of Ca-doped alumina nanopowders prepared by a new sol-gel route with seeding

ArticleJOURNAL OF THE EUROPEAN CERAMIC SOCIETY. 28(13):2479-2485(2008)journal articl

A New Deformed Supersymmetric Oscillator

We construct and discuss the Fock-space representation for a deformed oscillator with "peculiar" statistics. We show that corresponding algebra represents deformed supersymmetric oscillator.Comment: LATEX, 10 pages, no figures, to appear in Europhys.Let

Unified View of Deformed Single - Mode Oscillator Algebras

A general framework for the deformation of the single-mode oscillators is presented and all deformed single-mode oscillators are unified. The extensions of the Aric-Coon, genon, the para-Bose and the para-Fermi oscillators are proposed. The generalized harmonic oscillator considered by Brzezinski et al. is rederived in a simple way.Some remarks on deformation of $SU(1,1)$ and supersymmetry are made.Comment: 12 pages, Latex file, preprint RBI-TH-3/94,PMF-ZTF-3/94, February 1994. (to appear in Phys.Lett. B