1,591 research outputs found

    The Entomopathogenic Fungal Endophytes Purpureocillium lilacinum (Formerly Paecilomyces lilacinus) and Beauveria bassiana Negatively Affect Cotton Aphid Reproduction under Both Greenhouse and Field Conditions

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    The effects of two entomopathogenic fungal endophytes, Beauveria bassiana and Purpureocillium lilacinum (formerly Paecilomyces lilacinus), were assessed on the reproduction of cotton aphid, Aphis gossypii Glover (Homoptera:Aphididae), through in planta feeding trials. In replicate greenhouse and field trials, cotton plants (Gossypium hirsutum) were inoculated as seed treatments with two concentrations of B. bassiana or P. lilacinum conidia. Positive colonization of cotton by the endophytes was confirmed through potato dextrose agar (PDA) media plating and PCR analysis. Inoculation and colonization of cotton by either B. bassiana or P. lilacinum negatively affected aphid reproduction over periods of seven and 14 days in a series of greenhouse trials. Field trials were conducted in the summers of 2012 and 2013 in which cotton plants inoculated as seed treatments with B. bassiana and P. lilacinum were exposed to cotton aphids for 14 days. There was a significant overall effect of endophyte treatment on the number of cotton aphids per plant. Plants inoculated with B. bassiana had significantly lower numbers of aphids across both years. The number of aphids on plants inoculated with P. lilacinum exhibited a similar, but non-significant, reduction in numbers relative to control plants. We also tested the pathogenicity of both P. lilacinum and B. bassiana strains used in the experiments against cotton aphids in a survival experiment where 60% and 57% of treated aphids, respectively, died from infection over seven days versus 10% mortality among control insects. Our results demonstrate (i) the successful establishment of P. lilacinum and B. bassiana as endophytes in cotton via seed inoculation, (ii) subsequent negative effects of the presence of both target endophytes on cotton aphid reproduction using whole plant assays, and (iii) that the P. lilacinum strain used is both endophytic and pathogenic to cotton aphids. Our results illustrate the potential of using these endophytes for the biological control of aphids and other herbivores under greenhouse and field conditions

    Notes on Certain Newton Gravity Mechanisms of Wave Function Localisation and Decoherence

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    Both the additional non-linear term in the Schr\"odinger equation and the additional non-Hamiltonian term in the von Neumann equation, proposed to ensure localisation and decoherence of macro-objects, resp., contain the same Newtonian interaction potential formally. We discuss certain aspects that are common for both equations. In particular, we calculate the enhancement of the proposed localisation and/or decoherence effects, which would take place if one could lower the conventional length-cutoff and resolve the mass density on the interatomic scale.Comment: 8pp LaTex, Submitted to J. Phys. A: Math-Gen, for the special issue ``The Quantum Universe'' in honor of G. C. Ghirard

    How Big Can Anomalous W Couplings Be?

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    Conventional wisdom has it that anomalous gauge-boson self-couplings can be at most a percent or so in size. We test this wisdom by computing these couplings at one loop in a generic renormalizable model of new physics. (For technical reasons we consider the CP-violating couplings here, but our results apply more generally.) By surveying the parameter space we find that the largest couplings (several percent) are obtained when the new particles are at the weak scale. For heavy new physics we compare our findings with expectations based on an effective-lagrangian analysis. We find general patterns of induced couplings which robustly reflect the nature of the underlying physics. We build representative models for which the new physics could be first detected in the anomalous gauge couplings.Comment: 40 pages, 11 figures, (dvi file and figures combined into a uuencoded compressed file), (We correct an error in eq. 39 and its associated figure (9). No changes at all to the text.), McGill-93/40, UQAM-PHE-93/03, NEIPH-93-00

    Is there a relativistic nonlinear generalization of quantum mechanics?

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    Yes, there is. - A new kind of gauge theory is introduced, where the minimal coupling and corresponding covariant derivatives are defined in the space of functions pertaining to the functional Schroedinger picture of a given field theory. While, for simplicity, we study the example of an U(1) symmetry, this kind of gauge theory can accommodate other symmetries as well. We consider the resulting relativistic nonlinear extension of quantum mechanics and show that it incorporates gravity in the (0+1)-dimensional limit, where it leads to the Schroedinger-Newton equations. Gravity is encoded here into a universal nonlinear extension of quantum theory. The probabilistic interpretation, i.e. Born's rule, holds provided the underlying model has only dimensionless parameters.Comment: 10 pages; talk at DICE 2006 (Piombino, September 11-15, 2006); to appear in Journal of Physics: Conference Series (2007

    Fabrication of Triangular Nanobeam Waveguide Networks in Bulk diamond Using Single-Crystal Silicon Hard Masks

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    A scalable approach for integrated photonic networks in single-crystal diamond using triangular etching of bulk samples is presented. We describe designs of high quality factor (Q=2.51x10^6) photonic crystal cavities with low mode volume (Vm=1.062x({\lambda}/n)^3), which are connected via waveguides supported by suspension structures with predicted transmission loss of only 0.05 dB. We demonstrate the fabrication of these structures using transferred single-crystal silicon hard masks and angular dry etching, yielding photonic crystal cavities in the visible spectrum with measured quality factors in excess of Q=3x103.Comment: This article will be published in Applied Physics Letter
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