7,863 research outputs found

    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)

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    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

    Simulation of transition dynamics to high confinement in fusion plasmas

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    The transition dynamics from the low (L) to the high (H) confinement mode in magnetically confined plasmas is investigated using a first-principles four-field fluid model. Numerical results are in close agreement with measurements from the Experimental Advanced Superconducting Tokamak - EAST. Particularly, the slow transition with an intermediate dithering phase is well reproduced by the numerical solutions. Additionally, the model reproduces the experimentally determined L-H transition power threshold scaling that the ion power threshold increases with increasing particle density. The results hold promise for developing predictive models of the transition, essential for understanding and optimizing future fusion power reactors

    Strong Orientation Effects in Ionization of H2+_2^+ by Short, Intense, High-Frequency Light Sources

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    We present three dimensional time-dependent calculations of ionization of arbitrarily spatially oriented H2+_2^+ by attosecond, intense, high-frequency laser fields. The ionization probability shows a strong dependence on both the internuclear distance and the relative orientation between the laser field and the internuclear axis.Comment: 4 pages, 4 figure

    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)

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    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 (Archips argyrospilus (Walker) than the lower traps. The results with threelined leafroller (Pandemis limitata (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

    Electronic structure of the ferromagnetic superconductor UCoGe from first principles

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    The superconductor UCoGe is analyzed with electronic structure calculations using Linearized Augmented Plane Wave method based on Density Functional Theory. Ferromagnetic and antiferromagnetic calculations with and without correlations (via LDA+U) were done. In this compound the Fermi level is situated in a region where the main contribution to DOS comes from the U-5f orbital. The magnetic moment is mainly due to the Co-3d orbital with a small contribution from the U-5f orbital. The possibility of fully non-collinear magnetism in this compound seems to be ruled out. These results are compared with the isostructural compound URhGe, in this case the magnetism comes mostly from the U-5f orbital

    Physics and Astrophysics of Strange Quark Matter

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    3-flavor quark matter (strange quark matter; SQM) can be stable or metastable for a wide range of strong interaction parameters. If so, SQM can play an important role in cosmology, neutron stars, cosmic ray physics, and relativistic heavy-ion collisions. As an example of the intimate connections between astrophysics and heavy-ion collision physics, this Chapter gives an overview of the physical properties of SQM in bulk and of small-baryon number strangelets; discusses the possible formation, destruction, and implications of lumps of SQM (quark nuggets) in the early Universe; and describes the structure and signature of strange stars, as well as formation and detection of strangelets in cosmic rays. It is concluded, that astrophysical and laboratory searches are complementary in many respects, and that both should be pursued to test the intriguing possibility of a strange ground state for hadronic matter, and (more generally) to improve our knowledge of the strong interactions.Comment: 45 pages incl. figures. To appear in "Hadrons in Dense Matter and Hadrosynthesis", Lecture Notes in Physics, Springer Verlag (ed. J.Cleymans

    Probabilistic state preparation of a single molecular ion by projection measurement

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    We show how to prepare a single molecular ion in a specific internal quantum state in a situation where the molecule is trapped and sympathetically cooled by an atomic ion and where its internal degrees of freedom are initially in thermal equilibrium with the surroundings. The scheme is based on conditional creation of correlation between the internal state of the molecule and the translational state of the collective motion of the two ions, followed by a projection measurement of this collective mode by atomic ion shelving techniques. State preparation in a large number of internal states is possible.Comment: 4 pages, 2 figures, 2 table

    Trapping of strangelets in the geomagnetic field

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    Strangelets coming from the interstellar medium (ISM) are an interesting target to experiments searching for evidence of this hypothetic state of hadronic matter. We entertain the possibility of a {\it trapped} strangelet population, quite analogous to ordinary nuclei and electron belts. For a population of strangelets to be trapped by the geomagnetic field, these incoming particles would have to fulfill certain conditions, namely having magnetic rigidities above the geomagnetic cutoff and below a certain threshold for adiabatic motion to hold. We show in this work that, for fully ionized strangelets, there is a narrow window for stable trapping. An estimate of the stationary population is presented and the dominant loss mechanisms discussed. It is shown that the population would be substantially enhanced with respect to the ISM flux (up to two orders of magnitude) due to quasi-stable trapping.Comment: 10 pp., 5 figure

    Production of Strange Clusters and Strange Matter in Nucleus-Nucleus Collisions at the AGS

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    Production probabilities for strange clusters and strange matter in Au+Au collisions at AGS energy are obtained in the thermal fireball model. The only parameters of the model, the baryon chemical potential and temperature, were determined from a description of the rather complete set of hadron yields from Si+nucleus collisions at the AGS. For the production of light nuclear fragments and strange clusters the results are similar to recent coalescence model calculations. Strange matter production with baryon number larger than 10 is predicted to be much smaller than any current experimental sensitivities.Comment: 9 Pages (no figures

    Colour-singlet strangelets at finite temperature

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    Considering massless uu and dd quarks, and massive (150 MeV) ss quarks in a bag with the bag pressure constant B1/4=145B^{1/4} = 145 MeV, a colour-singlet grand canonical partition function is constructed for temperatures T=1−30T = 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 250250 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 AA-values, the first deepest one occuring at A=2A=2, famous HH-particle ! (4) The shell structure at A=2A=2 vanishes only at T∼30T\sim 30 MeV, though for higher AA-values it happens so at T∼20T\sim 20 MeV.Comment: Revtex file(8 pages)+6 figures(ps files) available on request from first Autho
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