Stable operation of a synchronously pumped colliding-pulse mode-locked ring dye laser

Pulses of 100-fsec duration are obtained by synchronous pumping of a colliding-pulse ring dye laser with a mode-locked Ar+-ion laser. Stable operation of the synchronously pumped colliding-pulse mode-locked laser over hours was obtained by a suitable choice of the distance between the gain and the absorber in combination with an appro-priate pump-pulse sequence. Passive mode locking of a ring dye laser by the inter-action of two counterpropagating pulses in a thin sat-urable absorber (colliding-pulse mode locking) yields femtosecond laser pulses. ' In these lasers the gain medium (Rhodamine 6G) is pumped by a cw Ar+-ion laser. The saturable absorber (DODCI, 3,3-diethyl-oxadicarbocyanine iodide) synchronizes two counter-propagating pulses meeting in the absorber jet stream. The colliding pulses form a transient grating, which synchronizes and stabilizes the pulses.2 In order to ensure equal amplification for both counterpropagatin

Behandlung der eitrigen Klauengelenkentzündung beim Rind durch Gelenkresektion

Die eitrige Arthritis des distalen Interphalangealgelenkes ist eine relativ häufige, schwerwiegende Erkrankung der Rinderklaue. In vielen Fällen gelingt es, eine Amputation zu vermeiden und die Zehe durch Resektion des Gelenkes funktionstüchtig zu erhalten. Es wird über die Operationstechnik und über die Ergebnisse nach Gelenkresektion bei 281 Rindern verschiedenen Alters berichtet. Von diesen konnten 71 Tiere über Zeiträume zwischen drei Monaten und sechs Jahren postoperativ klinisch und röntgenologisch nachuntersucht werden. Der knöcherne Durchbau erfolgte zwischen dem 7. und 12. Monat nach der Operat i o n ; bei 41 Tieren (£58%) wurde eine vollständige Ankylosierung festgestellt. Von den 71 nachuntersuchten Rindern waren 59 Tiere (= 83%) an der operierten Gliedmaße beschwerdefrei. Die operierte Klaue unterstützte die Partnerklaue bei der Tragefunktion. Haltung auf Spaltenboden oder Weidegang waren weiterhin möglich. Im Vergleich zur Klauenamputation ist die postoperative Nutzungsdauer länger

Linear electric field frequency shift (important for next generation electric dipole moment searches) induced in confined gases by a magnetic field gradient

The search for particle electric dipole moments (edm) represents a most promising way to search for physics beyond the standard model. A number of groups are planning a new generation of experiments using stored gases of various kinds. In order to achieve the target sensitivities it will be necessary to deal with the systematic error resulting from the interaction of the well-known $\overrightarrow{v}\times \overrightarrow{E}$ field with magnetic field gradients (often referred to as the geometric phase effect (Commins, ED; Am. J. Phys. \QTR{bf}{59}, 1077 (1991), Pendlebury, JM \QTR{em}{et al;} Phys. Rev. \QTR{bf}{A70}, 032102 (2004)). This interaction produces a frequency shift linear in the electric field, mimicking an edm. In this work we introduce an analytic form for the velocity auto-correlation function which determines the velocity-position correlation function which in turn determines the behavior of the frequency shift (Lamoreaux, SK and Golub, R; Phys. Rev \QTR{bf}{A71}, 032104 (2005)) and show how it depends on the operating conditions of the experiment. We also discuss some additional issues.Comment: 21 pages, 5 figure

Small quark stars in the chromodielectric model

Equations of state for strange quark matter in beta equilibrium at high densities are used to investigate the structure (mass and radius) of compact objects. The chromodielectric model is used as a general framework for the quark interactions, which are mediated by chiral mesons, $\sigma$ and $\vec \pi$, and by a confining chiral singlet dynamical field, $\chi$. Using a quartic potential for $\chi$, two equations of state for the same set of model parameters are obtained, one with a minimum at around the nuclear matter density $\rho_0$ and the other at $\rho \sim 5 \rho_0$. Using the latter equation of state in the Tolman-Oppenheimer-Volkoff equations we found solutions corresponding to compact objects with $R\sim 5 - 8$ km and $M\sim M_\odot$. The phenomenology of recently discovered X-ray sources is compatible with the type of quark stars that we have obtained.Comment: 8 pages, AIP macros; Talk delivered at the Pan American Advanced Studies Institute (PASI) Conference "New States of Matter in Hadronic Interactions", Campos do Jordao, Brazil, January 200

Optical Hall Effect in the Integer Quantum Hall Regime

Optical Hall conductivity $\sigma_{xy}(\omega)$ is measured from the Faraday rotation for a GaAs/AlGaAs heterojunction quantum Hall system in the terahertz frequency regime. The Faraday rotation angle ($\sim$ fine structure constant $\sim$ mrad) is found to significantly deviate from the Drude-like behavior to exhibit a plateau-like structure around the Landau-level filling $\nu=2$. The result, which fits with the behavior expected from the carrier localization effect in the ac regime, indicates that the plateau structure, although not quantized, still exists in the terahertz regime.Comment: 4 pages, 4 figure

Automated water monitor system field demonstration test report. Volume 1: Executive summary

A system that performs water quality monitoring on-line and in real time much as it would be done in a spacecraft, was developed and demonstrated. The system has the capability to determine conformance to high effluent quality standards and to increase the potential for reclamation and reuse of water

Automated water monitor system field demonstration test report. Volume 2: Technical summary

The NASA Automatic Water Monitor System was installed in a water reclamation facility to evaluate the technical and cost feasibility of producing high quality reclaimed water. Data gathered during this field demonstration test are reported