The effect of height and density of sex pheromone traps on captures of male fruittree leafroller, Archips argyrospilus and threelined leafroller, Pandemis limitata (Lepid.: Tortricidae)

When sex pheromone traps in the upper third of a standard apple tree were compared with traps at head height, the upper traps captured far more fruittree leafroller moths (<i>Archips argyrospilus</i> (Walker) than the lower traps. The results with threelined leafroller (<i>Pandemis limitata</i> (Rob.) were reversed: traps at head height captured nearly twice as many moths as traps in the upper portion of a tree. Trap captures increased with trap/area up to 1 trap/ha. This density is probably sufficient for monitoring purposes

Angular Normal Modes of a Circular Coulomb Cluster

We investigate the angular normal modes for small oscillations about an equilibrium of a single-component coulomb cluster confined by a radially symmetric external potential to a circle. The dynamical matrix for this system is a Laplacian symmetrically circulant matrix and this result leads to an analytic solution for the eigenfrequencies of the angular normal modes. We also show the limiting dependence of the largest eigenfrequency for large numbers of particles

Gaps below strange star crusts

The gap caused by a strong electric field between the quark surface and nuclear crust of a strange star is studied in an improved model including gravity and pressure as well as electrostatic forces. The transition from gap to crust is followed in detail. The properties of the gap are investigated for a wide range of parameters assuming both color-flavor locked and non color-flavor locked strange star cores. The maximally allowed crust density is generally lower than that of neutron drip. Finite temperature is shown to increase the gap width, but the effect is significant only at extreme temperatures. Analytical approximations are derived and shown to provide useful fits to the numerical results.Comment: 12 pages incl. 14 figures. To appear in Physical Review

Charge order in Magnetite. An LDA+UU study

The electronic structure of the monoclinic structure of Fe$_3$O$_4$ is studied using both the local density approximation (LDA) and the LDA+$U$. The LDA gives only a small charge disproportionation, thus excluding that the structural distortion should be sufficient to give a charge order. The LDA+$U$ results in a charge disproportion along the c-axis in good agreement with the experiment. We also show how the effective $U$ can be calculated within the augmented plane wave methods

High-order harmonic generation from polyatomic molecules including nuclear motion and a nuclear modes analysis

We present a generic approach for treating the effect of nuclear motion in the high-order harmonic generation from polyatomic molecules. Our procedure relies on a separation of nuclear and electron dynamics where we account for the electronic part using the Lewenstein model and nuclear motion enters as a nuclear correlation function. We express the nuclear correlation function in terms of Franck-Condon factors which allows us to decompose nuclear motion into modes and identify the modes that are dominant in the high-order harmonic generation process. We show results for the isotopes CH$_4$ and CD$_4$ and thereby provide direct theoretical support for a recent experiment [Baker {\it et al.}, Science {\bf 312}, 424 (2006)] that uses high-order harmonic generation to probe the ultra-fast structural nuclear rearrangement of ionized methane.Comment: 6 pages, 6 figure

How to identify a Strange Star

Contrary to young neutron stars, young strange stars are not subject to the r-mode instability which slows rapidly rotating, hot neutron stars to rotation periods near 10 ms via gravitational wave emission. Young millisecond pulsars are therefore likely to be strange stars rather than neutron stars, or at least to contain significant quantities of quark matter in the interior.Comment: 4 pages, 1 figur

Colour-singlet strangelets at finite temperature

Considering massless $u$ and $d$ quarks, and massive (150 MeV) $s$ quarks in a bag with the bag pressure constant $B^{1/4} = 145$ MeV, a colour-singlet grand canonical partition function is constructed for temperatures $T = 1-30$ MeV. Then the stability of finite size strangelets is studied minimizing the free energy as a function of the radius of the bag. The colour-singlet restriction has several profound effects when compared to colour unprojected case: (1) Now bulk energy per baryon is increased by about $250$ MeV making the strange quark matter unbound. (2) The shell structures are more pronounced (deeper). (3) Positions of the shell closure are shifted to lower $A$-values, the first deepest one occuring at $A=2$, famous $H$-particle ! (4) The shell structure at $A=2$ vanishes only at $T\sim 30$ MeV, though for higher $A$-values it happens so at $T\sim 20$ MeV.Comment: Revtex file(8 pages)+6 figures(ps files) available on request from first Autho