1,567 research outputs found

    Larra bicolor Fabricius (Hymenoptera: Crabronidae): its distribution throughout Florida

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    We document the presence of Larra bicolor Fabricius (Hymenoptera: Crabronidae) in 46 of Florida's 67 counties. The species is represented by two stocks. The first (released in 1981) originated in Pará, Brazil, but was obtained from Puerto Rico, and became established in Broward County in southern Florida. The second (released in 1988) originated in Santa Cruz de la Sierra, Bolivia, and became established in Alachua County in northern Florida. The Bolivian stock, aided by additional satellite releases from Alachua County, is now widely distributed. The species probably occupies all counties in central and northern Florida, but may yet be absent from some southern counties. Introduction was made for classical biological control of invasive mole crickets

    Measures of oxidative state are primarily driven by extrinsic factors in a long-distance migrant

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    This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this recordData accessibility: Data are available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.j4k3t6f/1 [20].Oxidative stress is a likely consequence of hard physical exertion and thus a potential mediator of life-history trade-offs in migratory animals. However, little is known about the relative importance of intrinsic and extrinsic stressors on the oxidative state of individuals in wild populations. We quantified the relationships between air temperature, sex, body condition and three markers of oxidative state (malondialdehyde, superoxide dismutase and total antioxidant capacity) across hundreds of individuals of a long-distance migrant (the brent goose Branta bernicla hrota) during wintering and spring staging. We found that air temperature and migratory stage were the strongest predictors of oxidative state. This emphasizes the importance of extrinsic factors in regulating the oxidative state of migrating birds, with differential effects across the migration. The significance of abiotic effects demonstrates an additional mechanism by which changing climates may affect migratory costs.European Commissio

    Many-body position operator in lattice fermionic systems with periodic boundary conditions

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    A total position operator XX in the position representation is derived for lattice fermionic systems with periodic boundary conditions. The operator is shown to be Hermitian, the generator of translations in momentum space, and its time derivative is shown to correspond to the total current operator in a periodic system. The operator is such that its moments can be calculated up to any order. To demonstrate its utility finite size scaling is applied to the Brinkman-Rice transition as well as metallic and insulating Gutzwiller wavefunctions.Comment: to appear in Journal of Physics A: Mathematical and General (reference will be added later

    The EVerT2 (Effective Verruca Treatments) trial : a randomised controlled trial of needling versus nonsurgical debridement for the treatment of plantar verrucae

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    Background: Verrucae are a common foot skin pathology which can in some cases persist for many years. Plantar verrucae can be unsightly and painful. There are a range of treatment options including needling. Objectives: The EVerT2 trial aimed to evaluate the clinical and cost effectiveness of the needling procedure for the treatment of plantar verrucae, relative to callus debridement. Methods: This single centre randomised controlled trial recruited 60 participants (aged 18 years and over with a plantar verruca). Participants were randomised 1:1 to the intervention group (needling) or the control group (debridement of the overlying callus). The primary outcome was clearance of the index verruca at 12 weeks after randomisation. Secondary outcomes include recurrence of the verruca; clearance of all verrucae; number of verrucae; size of the index verruca; pain; and participant satisfaction at 12 and 24 weeks. A cost-effectiveness analysis was carried out from the NHS perspective over 12 weeks. Results: Sixty eligible patients were randomised (needling group n=29, 48.3%; debridement group n=31, 51.7%) and 53 were included in the primary analysis (needling n=28, 96.6%; debridement n=25, 80.7%). Clearance of the index verruca occurred in 8 (15.1%) participants (needling n=4, 14.3%; debridement n=4, 16.0%, p=0.86). The needling intervention costs were on average £14.33 (95% CI 5.32 to 23.35) more per patient than debridement. Conclusions: There is no evidence that the needling technique is more clinically or cost effective than callus debridement. The results show a significant improvement in pain outcomes after needling compared to the debridement treatment alone. Trial registration number: Current Controlled Trials ISRCTN1642944

    Wannier functions of elliptic one-gap potentials

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    Wannier functions of the one dimensional Schroedinger equation with elliptic one gap potentials are explicitly constructed. Properties of these functions are analytically and numerically investigated. In particular we derive an expression for the amplitude of the Wannier function in the origin, a power series expansion valid in the vicinity of the origin and an asymptotic expansion characterizing the decay of the Wannier function at large distances. Using these results we construct an approximate analytical expression of the Wannier function which is valid in the whole spatial domain and is in good agreement with numerical results.Comment: 24 pages, 5 figure

    Superconductivity in ferromagnetic metals and in compounds without inversion centre

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    The symmetry properties and the general overview of the superconductivity theory in the itinerant ferromagnets and in materials without space parity are presented. The basic notions of unconventional superconductivity are introduced in broad context of multiband superconductivity which is inherent property of ferromagnetic metals or metals without centre of inversion.Comment: 38 pages, no figure

    E1gE_{1g} model of superconducting UPt3_3

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    The phase diagram of superconducting UPt3_3 is explained in a Ginzburg-Landau theory starting from the hypothesis that the order parameter is a pseudo-spin singlet which transforms according to the E1gE_{1g} representation of the D6hD_{6h} point group. We show how to compute the positions of the phase boundaries both when the applied field is in the basal plane and when it is along the c-axis. The experimental phase diagrams as determined by longitudinal sound velocity data can be fit using a single set of parameters. In particular the crossing of the upper critical field curves for the two field directions and the apparent isotropy of the phase diagram are reproduced. The former is a result of the magnetic properties of UPt3_3 and their contribution to the free energy in the superconducting state. The latter is a consequence of an approximate particle-hole symmetry. Finally we extend the theory to finite pressure and show that, in contrast to other models, the E1gE_{1g} model explains the observed pressure dependence of the phase boundaries.Comment: RevTex, 29 pages, 18 PostScript figures in a uuencoded, gzipped tar file. PostScript version of paper, tar file of PostScript figures and individual PostScript figures are also available via anonymous ftp at ftp://nym.physics.wisc.edu/anonymou/papers/upt3

    Electron-Phonon Interaction and Ultrasonic Attenuation in the Ruthenate and Cuprate superconductors

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    This article derives an electron-phonon interaction suitable for interpreting ultrasonic attenuation measurements in the ruthenate and cuprate superconductors. The huge anisotropy found experimentally (Lupien et al., 2001) in Sr2RuO4 in the normal state is accounted for in terms of the layered square-lattice structure of Sr2RuO4, and the dominant contribution to the attenuation in Sr2RuO4 is found to be due to electrons in the gamma band. The experimental data in the superconducting state is found to be inconsistent with vertical lines nodes in the gap in either (100) or (110) planes. Also, a general method, based on the use of symmetry, is developed to allow for the analysis of ultrasonic attenuation experiments in superconductors in which the electronic band structure is complicated or not known. Our results, both for the normal-state anisotropy, and relating to the positions of the gap nodes in the superconducting state, are different from those obtained from analyses using a more traditional model for the electron-phonon interaction in terms of an isotropic electron stress tensor. Also, a brief discussion of the ultrasonic attenuation in UPt3 is given.Comment: 12 pages. Comments have been added to the original version of this article showing how, for the ultrasonic attenuation for a hexagonal crystal (which must be isotropic with respect to rotations about the c axis) our approach reproduces the results of the traditional isotropic electron stress tensor mode

    Odd Frequency Pairing in the Kondo Lattice

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    We discuss the possibility that heavy fermion superconductors involve odd-frequency pairing of the kind first considered by Berezinskii. Using a toy model for odd frequency triplet pairing in the Kondo lattice we are able to examine key properties of this new type of paired state. To make progress treating the strong nf=1n_f=1 constraint in the Kondo lattice model we use the technical trick of a Majorana representation of the local moments, which permits variational treatments of the model without a Gutzwiller approximation. The simplest mean field theory involves the development of bound states between the local moments and conduction electrons, characterized by a spinor order parameter. We show that this state is a stable realization of odd frequency triplet superconductivity with surfaces of gapless excitations whose spin and charge coherence factors vanish linearly in the quasiparticle energy. A T3T^3 NMR relaxation rate coexists with a linear specific heat. We discuss possible extensions of our toy model to describe heavy fermion superconductivity.Comment: 67 page

    Criterion for weak spin-orbit coupling in heavy-fermion superconductivity: A numerical renormalization-group study

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    A criterion for effective irrelevancy of the spin-orbit coupling in the heavy-fermion superconductivity is discussed on the basis of the impurity Anderson model with two sets of Kramers doublets. Using Wilson's numerical renormalization-group method, we demonstrate a formation of the quasiparticle as well as the renormalization of the rotational symmetry-breaking interaction in the lower Kramers doublet (quasispin) space. A comparison with the quasispin conserving interaction exhibits the effective irrelevancy of the symmetry-breaking interaction for the splitting of two doublets Delta larger than the characteristic energy of the local spin fluctuation T_K. The formula for the ratio of two interactions is also determined.Comment: 4 pages, 4 figures (2 color figures
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