Relativistic Models of Galaxies

A special form of the isotropic metric in cylindrical coordinates is used to construct what may be interpreted as the General Relativistic versions of some wellknown potential-density pairs used in Newtonian gravity to model three-dimensional distributions of matter in galaxies. The components of the energy-momentum tensor are calculated for the first two Miyamoto-Nagai potentials and a particular potential due to Satoh. The three potentials yield distributions of matter in which all tensions are pressures and all energy conditions are satisfied for certain ranges of the free parameters. A few non-planar geodesic orbits are computed for one of the potentials and compared with the Newtonian case. Rotation is also incorporated to the models and the effects of the source rotation on the rotation profile are calculated as first order corrections by using an approximate form of the Kerr metric in isotropic coordinates.Comment: 18 pages, 23 eps figures, uses mn2e.cls style file, to be published in MNRA

Free-jet acoustic investigation of high-radius-ratio coannular plug nozzles

The experimental and analytical results of a scale model simulated flight acoustic exploratory investigation of high radius ratio coannular plug nozzles with inverted velocity and temperature profiles are summarized. Six coannular plug nozzle configurations and a baseline convergent conical nozzle were tested for simulated flight acoustic evaluation. The nozzles were tested over a range of test conditions that are typical of a Variable Cycle Engine for application to advanced high speed aircraft. It was found that in simulate flight, the high radius ratio coannular plug nozzles maintain their jet noise and shock noise reduction features previously observed in static testing. The presence of nozzle bypass struts will not significantly affect the acousticn noise reduction features of a General Electric type nozzle design. A unique coannular plug nozzle flight acoustic spectral prediction method was identified and found to predict the measured results quite well. Special laser velocimeter and acoustic measurements were performed which have given new insights into the jet and shock noise reduction mechanisms of coannular plug nozzles with regard to identifying further benificial research efforts

Control of the apple sawfly Hoplocampa testudinea Klug in organic fruit growing and possible side effects of control strategies on Aphelinus mali Haldeman and other beneficial insects

The effect of Quassia extract on eggs and larvae of the apple sawfly Hoplocampa testudinea was studied. The efficacy of this extract is mainly due to an oral toxicity to the neonate sawfly larvae. The main active ingredients, Quassin and Neoquassin, were tested separately. Wheras Quassin has a considerable efficacy also on older larvae, Neoquassin is less efficient in this case. While Quassin and Neoquassin are found in different Quassia sources in varying relations to each other and have different efficacy, they have to be considered separately in the definition of extract quality by the content of active ingredients. These findings mean, that the “egg maturity” is not important for application date. Nevertheless, the application must take place before the larvae hatch. It was shown that low rates of Quassin (4-6 g/ha) can show very good results in the field, in other cases the rates necessary for good efficacy are much higher. This corresponds to farmers experience. Several factors as application technique and the condition of the blossom must be taken in consideration and will be object of further studies. The side effects of Quassin, Neoquassin and Quassia extract on Aphelinus mali and other beneficial arthropods were tested. Quassia is harmless to all organisms tested

Statistical hadronization of charm at SPS, RHIC and LHC

We study the production of charmonia and charmed hadrons for nucleus-nucleus collisions at SPS, RHIC, and LHC energies within the framework of the statistical hadronization model. Results from this model are compared to the observed centrality dependence of J/psi production at SPS energy. We further provide predictions for the centrality dependence of the production of open and hidden charm mesons at RHIC and LHC.Comment: Contribution to Quark Matter 2002, 4 pages, 3 figures; revised version including charmed hyperons (omitted in v1

Transverse energy distributions and J/ψJ/\psi production in Pb+Pb collisions

We have analyzed the latest NA50 data on transverse energy distributions and $J/\psi$ suppression in Pb+Pb collisions. The transverse energy distribution was analysed in the geometric model of AA collisions. In the geometric model, fluctuations in the number of NN collisions at fixed impact parameter are taken into account. Analysis suggests that in Pb+Pb collisions, individual NN collisions produces less $$, than in other AA collisions. The nucleons are more transparent in Pb+Pb collisions. The transverse energy dependence of the $J/\psi$ suppression was obtained following the model of Blaizot et al, where charmonium suppression is assumed to be 100% effective above a threshold density. With fluctuations in number of NN collisions taken into account, good fit to the data is obtained, with a single parameter, the threshold density.Comment: Revised version with better E_T fit. 4 pages, 2 figure

Free-jet acoustic investigation of high-radius-ratio coannular plug nozzles. Comprehensive data report, volume 2

Laser velocimeter data, collected as part of an acoustic investigation of coannular plug nozzles, is provided. The type of traverse, position, and histogram number is given along with the mean and turbulent velocity data. The velocites are normalized with respect to the outer flow velocity and the 'mixed' velocity

Nuclear suppression of heavy quark production at forward rapidities in relativistic heavy ion collisions

We calculate nuclear suppression $R_{AA}$ of heavy quarks produced from the initial fusion of partons in nucleus-nucleus collisions at RHIC and LHC energies. We take the shadowing as well as the energy loss suffered by them while passing through Quark Gluon Plasma into account. We obtain results for charm and bottom quarks at several rapidities using different mechanisms for energy loss, to see if we can distinguish between them.Comment: 21 pages including 13 figures. To appear in J. Phys.

Screening and Anti-Screening Effects in J/psi Production on Nuclei

The nuclear effects in J/psi hadro- and electroproduction on nuclei are considered in framework of reggeon approach. It is shown that screening regime which holds for electroproduction at x_F > 0.7 and for hadroproduction at x_F > -(0.3-0.4) is changed with anti-screening regime for smaller x_F values.Comment: 6 pages, 6 figures. Small changes in wordin