1,212 research outputs found

    Quantifying Thermal‐Imager Effectiveness for Detecting Bird Nests on Farms

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    We conducted a designed experiment to test whether having a thermal‐imaging camera available affected researchers’ nest detection rates when searching for bird nests in cropland and grassland habitat in an agricultural landscape of Iowa, USA, in 2016. With known active nests present, naïve observers searched for nests with and without a thermal imager available. We did not find a difference in detection probabilities, although only a large difference would have been detectable with our sample size. Extraneous heat signatures from reflected solar radiation and dense vegetation were key factors limiting the usefulness of thermal imagers for locating nests

    Generalized Conformal Quantum Mechanics of D0-brane

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    We study the generalized conformal quantum mechanics of the probe D0-brane in the near horizon background of the bound state of source D0-branes. We elaborate on the relationship of such model to the M theory in the light cone frame.Comment: 14 pages, RevTeX, revised version with added references to appear in Phys. Rev.

    The Conformal Penrose Limit and the Resolution of the pp-curvature Singularities

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    We consider the exact solutions of the supergravity theories in various dimensions in which the space-time has the form M_{d} x S^{D-d} where M_{d} is an Einstein space admitting a conformal Killing vector and S^{D-d} is a sphere of an appropriate dimension. We show that, if the cosmological constant of M_{d} is negative and the conformal Killing vector is space-like, then such solutions will have a conformal Penrose limit: M^{(0)}_{d} x S^{D-d} where M^{(0)}_{d} is a generalized d-dimensional AdS plane wave. We study the properties of the limiting solutions and find that M^{(0)}_{d} has 1/4 supersymmetry as well as a Virasoro symmetry. We also describe how the pp-curvature singularity of M^{(0)}_{d} is resolved in the particular case of the D6-branes of D=10 type IIA supergravity theory. This distinguished case provides an interesting generalization of the plane waves in D=11 supergravity theory and suggests a duality between the SU(2) gauged d=8 supergravity of Salam and Sezgin on M^{(0)}_{8} and the d=7 ungauged supergravity theory on its pp-wave boundary.Comment: 20 pages, LaTeX; typos corrected, journal versio

    Conformal Maxwell theory as a singleton field theory on AdS_5, IIB three-branes and duality

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    We examine the boundary conditions associated with extended supersymmetric Maxwell theory in 5-dimensional anti-De Sitter space. Excitations on the boundary are identical to those of ordinary 4-dimensional conformal invariant super electrodynammics. Extrapolations of these excitations give rise to a 5-dimensional topological gauge theory of the singleton type. The possibility of a connection of this phenomenon to the world volume theory of 3-branes in IIB string theory is discussed.Comment: 19 pages, TeX, no figures; v2: misprints corrected, references added, discussion on Chern-Simons couplings revised. v3: References added, misprints corrected and a discussion in section 2 revised. v4: Typos corrected and reference adde

    Nieuwe grondhouding in ruimtelijk beleid

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    Op basis van een analyse van de veranderende ruimtelijke praktijk aan de hand van de ideeën van Williamson schetsen de auteurs van dit artikel twee handelingsperspectieven waarmee een nieuwe vorm van ruimtelijk beleid vorm kan krijgen. Twee handelingsperspectieven waarbij niet alleen het institutionele landschap, maar ook de planningscultuur en governance capaciteiten van ruimtelijke planners in beschouwing worden genomen. Het gaat om strategisch navigeren en lerend organiseren

    The Gaugings of Maximal D=6 Supergravity

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    We construct the most general gaugings of the maximal D=6 supergravity. The theory is (2,2) supersymmetric, and possesses an on-shell SO(5,5) duality symmetry which plays a key role in determining its couplings. The field content includes 16 vector fields that carry a chiral spinor representation of the duality group. We utilize the embedding tensor method which determines the appropriate combinations of these vectors that participate in gauging of a suitable subgroup of SO(5,5). The construction also introduces the magnetic duals of the 5 two-form potentials and 16 vector fields.Comment: 34 pages, latex, reference added, typo's corrected and minor improvements mad

    The influence of age and gender in the interaction with touch screens

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    Touch screens are nowadays one of the major interfaces in the interaction between humans and technology, mostly due to the significant growth in the use of smartphones and tablets in the last years. This broad use, that reaches people from all strata of society, makes touch screens a relevant tool to study the mechanisms that influence the way we interact with electronic devices. In this paper we collect data regarding the interaction patterns of different users with mobile devices. We present a way to formalize these interaction patterns and analyze how aspects such as age and gender influence them. The results of this research may be relevant for developing mobile applications that identify and adapt to the users or their characteristics, including impairments in fine motor skills or in cognitive function.Fundos Europeus Estruturais e de Investimento (FEEI) through Programa Operacional Regional Norte, in the scope of project NORTE01-0145-FEDER-02357

    Supersymmteric Null-like Holographic Cosmologies

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    We construct a new class of 1/4-BPS time dependent domain-wall solutions with null-like metric and dilaton in type II supergravities, which admit a null-like big bang singularity. Based on the domain-wall/QFT correspondence, these solutions are dual to 1/4-supersymmetric quantum field theories living on a boundary cosmological background with time dependent coupling constant and UV cutoff. In particular we evaluate the holographic cc function for the 2-dimensional dual field theory living on the corresponding null-like cosmology. We find that this cc function runs in accordance with the cc-theorem as the boundary universe evolves, this means that the number of degrees of freedom is divergent at big bang and suggests the possible resolution of big bang singularity.Comment: 26 pages;v2 references adde

    Phase transition and hyperscaling violation for scalar Black Branes

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    We investigate the thermodynamical behavior and the scaling symmetries of the scalar dressed black brane (BB) solutions of a recently proposed, exactly integrable Einstein-scalar gravity model [1], which also arises as compactification of (p-1)-branes with a smeared charge. The extremal, zero temperature, solution is a scalar soliton interpolating between a conformal invariant AdS vacuum in the near-horizon region and a scale covariant metric (generating hyperscaling violation on the boundary field theory) asymptotically. We show explicitly that for the boundary field theory this implies the emergence of an UV length scale (related to the size of the brane), which decouples in the IR, where conformal invariance is restored. We also show that at high temperatures the system undergoes a phase transition. Whereas at small temperature the Schwarzschild-AdS BB is stable, above a critical temperature the scale covariant, scalar-dressed BB solution, becomes energetically preferred. We calculate the critical exponent z and the hyperscaling violation parameter of the scalar-dressed phase. In particular we show that the hyperscaling violation parameter is always negative. We also show that the above features are not a peculiarity of the exact integrable model of Ref.[1], but are a quite generic feature of Einstein-scalar and Einstein-Maxwell-scalar gravity models for which the squared-mass of the scalar field is positive and the potential vanishes exponentially as the scalar field goes to minus infinity.Comment: 20 pages, 4 figures. In the revised version it has been pointed out that the Einstein-scalar gravity model considered in the paper also arises as compactification of black p-branes with smeared charge
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