42 research outputs found
Mass and width of sigma(750) scalar meson from measurements of piN->pi(-)pi(+)N on polarized targets
The measurements of reactions at 17.2
GeV/c and at 5.98 and 11.85 GeV/c made at
CERN with polarized targets provide a model-independent and
solution-independent evidence for a narrow scalar state sigma(750). The
original chi^2 minimization method and the recent Monte Carlo method for
amplitude analysis of data at 17.2 GeV/c are in excellent agreement. Both
methods find that the mass distribution of the measured amplitude with recoil transversity ``up'' resonates near 750 MeV while the
amplitude with recoil transversity ``down'' is large and
nonresonating. The amplitude contributes as a strong background
to S-wave intensity I_S = (|S|^2 + |\overline S |^2)\Sigma\sigmaI_S|\overline S |^2\Sigmatm_\sigma = 753 \pm 19\Gamma_\sigma = 108 \pm 53\sigma(750)\sigma(750)\gamma\gamma \to \pi\pi\pi\pi$ phase shifts .Comment: 77 page
Proton-Antiproton Annihilation and Meson Spectroscopy with the Crystal Barrel
This report reviews the achievements of the Crystal Barrel experiment at the
Low Energy Antiproton Ring (LEAR) at CERN. During seven years of operation
Crystal Barrel has collected very large statistical samples in pbarp
annihilation, especially at rest and with emphasis on final states with high
neutral multiplicity. The measured rates for annihilation into various two-body
channels and for electromagnetic processes have been used to test simple models
for the annihilation mechanism based on the quark internal structure of
hadrons. From three-body annihilations three scalar mesons, a0(1450), f0(1370)
and f0(1500) have been established in various decay modes. One of them,
f0(1500), may be identified with the expected ground state scalar glueball.Comment: 64 pages, LATEX file, 36 figures are available as ps files at
http://afuz01.cern.ch/claude/ Submitted to Reviews of Modern Physic
Consensus guidelines for the use and interpretation of angiogenesis assays
The formation of new blood vessels, or angiogenesis, is a complex process that plays important roles in growth and development, tissue and organ regeneration, as well as numerous pathological conditions. Angiogenesis undergoes multiple discrete steps that can be individually evaluated and quantified by a large number of bioassays. These independent assessments hold advantages but also have limitations. This article describes in vivo, ex vivo, and in vitro bioassays that are available for the evaluation of angiogenesis and highlights critical aspects that are relevant for their execution and proper interpretation. As such, this collaborative work is the first edition of consensus guidelines on angiogenesis bioassays to serve for current and future reference
Roles of glial cells in synapse development
Brain function relies on communication among neurons via highly specialized contacts, the synapses, and synaptic dysfunction lies at the heart of age-, disease-, and injury-induced defects of the nervous system. For these reasons, the formation—and repair—of synaptic connections is a major focus of neuroscience research. In this review, I summarize recent evidence that synapse development is not a cell-autonomous process and that its distinct phases depend on assistance from the so-called glial cells. The results supporting this view concern synapses in the central nervous system as well as neuromuscular junctions and originate from experimental models ranging from cell cultures to living flies, worms, and mice. Peeking at the future, I will highlight recent technical advances that are likely to revolutionize our views on synapse–glia interactions in the developing, adult and diseased brain
Discussion concernant les fonctions des courtiers et agents de change, de commerce et de banque, lors de la séance du 27 mars 1791
Roussillou Pierre-Augustin, Prieur Pierre-Louis, Defermon des Chapelières Jacques, Leleu de la Ville au Bois Claude Antoine, Bouche Charles-François. Discussion concernant les fonctions des courtiers et agents de change, de commerce et de banque, lors de la séance du 27 mars 1791. In: Archives Parlementaires de 1787 à 1860 - Première série (1787-1799) Tome XXIV - Du 10 mars 1791 au 12 avril 1791. Paris : Librairie Administrative P. Dupont, 1886. p. 405