2,695 research outputs found

    Energy-Momentum Complex in M\o ller's Tetrad Theory of Gravitation

    Full text link
    M\o ller's Tetrad Theory of Gravitation is examined with regard to the energy-momentum complex. The energy-momentum complex as well as the superpotential associated with M\o ller's theory are derived. M\o ller's field equations are solved in the case of spherical symmetry. Two different solutions, giving rise to the same metric, are obtained. The energy associated with one solution is found to be twice the energy associated with the other. Some suggestions to get out of this inconsistency are discussed at the end of the paper.Comment: LaTeX2e with AMS-LaTeX 1.2, 13 page

    On the dependence between UV luminosity and Lyman-alpha equivalent width in high redshift galaxies

    Full text link
    We show that with the simple assumption of no correlation between the Ly-alpha equivalent width and the UV luminosity of a galaxy, the observed distribution of high redshift galaxies in an equivalent width - absolute UV magnitude plane can be reproduced. We further show that there is no dependence between Ly-alpha equivalent width and Ly-alpha luminosity in a sample of Ly-alpha emitters. The test was expanded to Lyman-break galaxies and again no dependence was found. Simultaneously, we show that a recently proposed lack of large equivalent width, UV bright galaxies (Ando et al. 2006) can be explained by a simple observational effect, based on too small survey volumes.Comment: 7 pages, 3 figures, 2 tables, accepted in MNRA

    Chromosome assignment of two cloned DNA probes hybridizing predominantly to human sex chromosomes

    Get PDF
    In situ hybridization experiments were carried out with two clones, YACG 35 and 2.8, which had been selected from two genomic libraries strongly enriched for the human Y chromosome. Besides the human Y chromosome, both sequences strongly hybridized to the human X chromosome, with few minor binding sites on autosomes. In particular, on the X chromosome DNA from clone YACG 35 hybridized to the centromeric region and the distal part of the short arm (Xp2.2). On the Y chromosome, the sequence was assigned to one site situated in the border region between Yq1.1 and Yq1.2. DNA from clone 2.8 also hybridized to the centromeric region of the X and the distal part of the short arm (Xq2.2). On the Y, however, two binding sites were observed (Yp1.1 and Yq1.2). The findings indicate that sex chromosomal sequences may be localized in homologous regions (as suggested from meiotic pairing) but also at ectopic sites

    Radiatively Induced Neutrino Masses and Large Higgs-Neutrino Couplings in the Standard Model with Majorana Fields

    Get PDF
    The Higgs sector of the Standard Model with one right-handed neutrino per family is systematically analyzed. In a model with intergenerational independent mixings between families, we can account for very light neutrinos acquiring Majorana masses radiatively at the first electroweak loop level. We also find that in such a scenario the Higgs coupling to the light-heavy neutrinos and to the heavy-heavy ones may be remarkably enhanced with significant implications for the production of these heavy neutrinos at high energy colliders.Comment: Making the text of an old paper electronically availabl

    A relativistic parton cascade with radiation

    Get PDF
    We consider the evolution of a parton system which is formed at the central rapidity region just after an ultrarelativistic heavy ion collision. The evolution of the system, which is composed of gluons, quarks and antiquarks, is described by a relativistic Boltzmann equations with collision terms including radiation and retardation effects. The equations are solved by the test particle method using Monte-Carlo sampling. Our simulations do not show any evidence of kinetic equilibration, unless the cross sections are artificially increased to unrealistically large values.Comment: 14 pages, 4 figure

    On the Stereochemistry of the Cations in the Doping Block of Superconducting Copper-Oxides

    Full text link
    Metal-oxygen complexes containing Cu,- Tl-, Hg-, Bi- and Pb-cations are electronically active in superconducting copper-oxides by stabilizing single phases with enhanced TcT_c, whereas other metal-oxygen complexes deteriorate copper-oxide superconductivity. Cu, Tl, Hg, Bi, Pb in their actual oxidation states are closed shell d10d^{10} or inert s2s^2 pair ions. Their electronic configurations have a strong tendency to polarize the oxygen environment. The closed shell dd ions with low lying nd10nd9(n+1)snd^{10}\leftrightarrow nd^9(n+1)s excitations form linear complexes through dz2sd_{z^2}-s hybridization polarizing the apical oxygens. Comparatively low nd9(n+1)snd^9(n+1)s excitation energies distinguish Cu1+,3+,Tl3+,Hg2+\rm Cu^{1+,3+}, Tl^{3+}, Hg^{2+} from other closed shell d10d^{10} ions deteriorating copper-oxide superconductivity, {\it e.g.} Zn2+\rm Zn^{2+}.Comment: 5 pages, uses REVTEX. To be published in: J. Superconductivity, Proc. Int. Workshop on "Phase Separation, Electronic Inhomogenities and Related Mechanisms for High T_c Superconductors", Erice (Sicily) 9-15 July 199

    New Fermions at e+^+e^- Colliders: II.~Signals and Backgrounds

    Full text link
    We discuss the production, at high--energy e+^+e^- linear colliders, of new heavy fermions predicted by extensions of the Standard Model. We analyze in great details the various signals and the corresponding backgrounds for both pair production and single production in association with ordinary fermions. Concentrating on new leptons, we use a model detector for e+^+e^- collisions at a center of mass energy of 500 GeV, to illustrate the discovery potential of the Next Linear Colliders.Comment: 22 pages + 9 figures (not included: available by mail from A. Djouadi), Preprint UdeM-LPN-TH-93-15

    Comparison between interstitial laser thermotherapy and excision of an adenocarcinoma transplanted into rat liver.

    Get PDF
    The aim of this study was to compare interstitial laser thermotherapy with excision of a liver tumour. A dimethylhydrazine-induced adenocarcinoma was transplanted (implanted if not stated otherwise) into the left lateral lobe of the rat liver, and treatment was performed 8 days later. In the main experiment, rats were treated with resection of the tumour-bearing lobe or underwent interstitial laser thermotherapy, which was performed at a steady-state temperature of 46 degrees C for 30 min, 3 mm from the tumour margin. The incidence and extent of intraperitoneal spread was smaller after laser thermotherapy than after resection of the tumour-bearing lobe, with no difference in local control. Metastatic spread after resection of the median liver lobe was similar to that observed after sham procedures for thermotherapy or resection, suggesting that the advantage of thermotherapy was not due to a difference in surgical trauma. Additional studies showed that laser thermotherapy reduced intraperitoneal spread when treatment was suboptimal or in a tumour inoculation model and suggested that immunological mechanisms might be involved. It is concluded that interstitial laser thermotherapy reduces spread of liver tumour compared with resection
    corecore