Comparison of Isoscalar Vector Meson Production Cross Sections in Proton-Proton Collisions

The reaction $pp\to pp\bf \omega$ was investigated with the TOF spectrometer, which is an external experiment at the accelerator COSY (Forschungszentrum J\"ulich, Germany). Total as well as differential cross sections were determined at an excess energy of $93 MeV$ ($p_{beam}=2950 MeV/c$). Using the total cross section of $(9.0\pm 0.7 \pm1.1) \mu b$ for the reaction $pp\to pp\omega$ determined here and existing data for the reaction $pp\to pp\bf \phi$, the ratio $\mathcal{R}_{\phi/\omega}=\sigma_\phi/\sigma_\omega$ turns out to be significantly larger than expected by the Okubo-Zweig-Iizuka (OZI) rule. The uncertainty of this ratio is considerably smaller than in previous determinations. The differential distributions show that the $\omega$ production is still dominated by S-wave production at this excess energy, however higher partial waves clearly contribute. A comparison of the measured angular distributions for $\omega$ production to published distributions for $\phi$ production at $83 MeV$ shows that the data are consistent with an identical production mechanism for both vector mesons

Production of ω\omega mesons in proton-proton collisions

The cross section for the production of $\omega$ mesons in proton-proton collisions has been measured in a previously unexplored region of incident energies. Cross sections were extracted at 92 MeV and 173 MeV excess energy, respectively. The angular distribution of the $\omega$ at $\epsilon$=173 MeV is strongly anisotropic, demonstrating the importance of partial waves beyond pure s-wave production at this energy.Comment: 12 pages, 4 figures submitted to Physics Letters B v2: figure 1 added, discussion detailing the data analysis, figure 3 (fig. 2 in v1) modified in line styles and systematic errors displayed on dat

Influence of N*-resonances on hyperon production in the channel pp->K+ Lambda p at 2.95, 3.20 and 3.30 GeV/c beam momentum

Hyperon production in the threshold region was studied in the reaction pp -> K+Lp using the time-of-flight spectrometer COSY-TOF. Exclusive data, covering the full phase-space, were taken at the three different beam momenta of p_beam=2.95, 3.20 and 3.30 GeV/c, corresponding to excess energies of epsilon=204, 285 and 316 MeV, respectively. Total cross-sections were deduced for the three beam momenta to be 23.9+/-0.8 +/-2.0 ub, 28.4+/-1.3 +/-2.2 ub and 35.0+/-1.3 +/-3.0 ub. Differential observables including Dalitz plots were obtained. The analysis of the Dalitz plots reveals a strong influence of the N(1650)-resonance at p_beam=2.95 GeV/c, whereas for the higher momenta an increasing relative contribution of the N(1710)- and/or of the N(1720)-resonance was observed. In addition, the pL-final-state interaction turned out to have a significant influence on the Dalitz plot distribution.Comment: accepted for publication at Physics Letters B; some minor text changes were done; also the scale of the ordinates of figure 9 has been changed

Genetic alterations of the SUMO isopeptidase SENP6 drive lymphomagenesis and genetic instability in diffuse large B-cell lymphoma

SUMOylation is a post-translational modification of proteins that regulates these proteins' localization, turnover or function. Aberrant SUMOylation is frequently found in cancers but its origin remains elusive. Using a genome-wide transposon mutagenesis screen in a MYC-driven B-cell lymphoma model, we here identify the SUMO isopeptidase (or deconjugase) SENP6 as a tumor suppressor that links unrestricted SUMOylation to tumor development and progression. Notably, SENP6 is recurrently deleted in human lymphomas and SENP6 deficiency results in unrestricted SUMOylation. Mechanistically, SENP6 loss triggers release of DNA repair- and genome maintenance-associated protein complexes from chromatin thereby impairing DNA repair in response to DNA damages and ultimately promoting genomic instability. In line with this hypothesis, SENP6 deficiency drives synthetic lethality to Poly-ADP-Ribose-Polymerase (PARP) inhibition. Together, our results link SENP6 loss to defective genome maintenance and reveal the potential therapeutic application of PARP inhibitors in B-cell lymphoma

An investigation of the dynamic characteristics of a two-gyro computing system for aerodynamics-lead pursuit courses

This thesis document was issued under the authority of another institution, not NPS. At the time it was written, a copy was added to the NPS Library collection for reasons not now known.  It has been included in the digital archive for its historical value to NPS.  Not believed to be a CIVINS (Civilian Institutions) title.In the field of fire control, one of the most important problems confronting the designer is that of furnishing an accurate solution for the control of fire from fixed guns carried by an airplanes flying along a curved path. In order to overcome this problem, sights of various types have been or are being designed. The type considered in this thesis is a gyro-computing, disturbed-line-of-sight type of gunsight. With the computer case of the gunsight being rigidly mounted to the structure of the attacking airplane, the foremost problem is to determined the effect of any possible motion of the computer case on the indicated sight prediction angle determined by the computer.http://www.archive.org/details/investigationofd00holmLieutenant Commander, United States Nav

Solarthermie-2000. Teilprogramm 2: Wissenschaftlich-technische Programmbegleitung Abschlussbericht

Im Rahmen des Teilprogramms 2 zu 'Solarthermie-2000' sollen etwa 100 grosse thermische Solaranlagen (Kollektorflaeche ueber 100 m"2) installiert und mit Hilfe eines sehr ausfuehrlichen Messprogramms detailliert untersucht werden. Zum Abschluss dieses Projekts waren etwa 50 Anlagen bewilligt und ca. 40 davon im regulaeren oder im probenweisen Betrieb. Die bisherigen Analysen zum Betriebsverhalten der Systeme lieferten ausgezeichnete Erkenntnisse, die sich vor allem in folgenden beispielhaft genannten Punkten niederschlugen: (a) Der Verbrauch in der sommerlichen Schwachlastperiode muss fuer die Dimensionierung der Solaranlagen benutzt werden, will man Stillstandzeiten vermeiden und Systeme mit hoher Effizienz und niedrigen Preisen fuer die Solarwaerme (0,20-0,25 DM/kWh), die nahezu konkurrenzfaehig sind zur Waerme aus konv. Systemen, errichten. Die in Normen genannten Verbrauchswerte sind zu hoch. (b) Nicht nur das Kollektorfeld muss optimal dimensioniert werden, sondern jede einzelne der Systemkomponenten muss sehr sorgfaeltig ausglegt werden (Solarspeicher, Waermetauscher, hydraulische Verschaltung der Kollektorfelder, Pumpen etc.). (c) Der Systemaufbau sollte moeglichst einfach gestaltet werden. Bei der Anbindung an das konventionelle System sind dessen besondere Betriebsbedingungen zu beachten. Zu den vielen Einzelpunkten der Auslegung und des Aufbaus eines thermischen Solarsystems zur Trinkwassererwaermung sind ausfuehrliche Hinweise im Bericht gegeben. Der Bericht stellt daher fuer Anlagenplaner und -installateure, aber auch fuer Konponentenhersteller oder Anlagenbetreiber ein hervorragendes Werkzeug in ihren Arbeitsbereichen dar. (orig.)Within subprogramme 2 of 'Solarthermie-2000' about 100 large solar thermal systems (collector area>100 m"2) for domestic hot water production shall be installed. A very extensive monitoring equipment is included to allow intensive investigations into the behaviour of the systems. At the time of the end of the project, more than 50 systems have been sponsored. About 40 of them were already in regular or in testing operation. The investigations into the operation behaviour of the systems have been leading to very interesting results. Some of the most important are listed below: (a) to avoid system stagnation and to reach a high system efficiency as well as low prices for the solar thermal energy (about 0,20-0,25 DM/kWh), near to those of energy produced with conventional energy systems, the hot water demand during the time of summer-holidays is to be used for dimensioning the solar system. The values for hot water demand given in different technical guidelines are often too high. (b) not only the collector field has to be dimensioned very carefully but also all the different components of the system (solar storages, heat exchangers, hydraulic connection of the collectors, pumps etc.) (c) the design of the system should be as simple as possible. The connection to the conventional system has to take into account the special operating modes of this system. Very detailed informations about the great number of problems occuring when planning or installing a solar thermal system are given in the report and the publications. The report and the publications named above may serve as a very important tool for planers and plumbers as well as for companies producing components for solar systems and for owners of these systems. (orig.)SIGLEAvailable from TIB Hannover: F01B1480 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman