13,902 research outputs found

    Localised AdS5×S5\bf{AdS_5\times S^5} Black Holes

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    We numerically construct asymptotically global AdS5×S5\mathrm{AdS}_5\times \mathrm{S}^5 black holes that are localised on the S5\mathrm{S}^5. These are solutions to type IIB supergravity with S8\mathrm S^8 horizon topology that dominate the theory in the microcanonical ensemble at small energies. At higher energies, there is a first-order phase transition to AdS5\mathrm{AdS}_5-Schwarzschild×S5\times \mathrm{S}^5. By the AdS/CFT correspondence, this transition is dual to spontaneously breaking the SO(6)SO(6) R-symmetry of N=4\mathcal N=4 super Yang-Mills down to SO(5)SO(5). We extrapolate the location of this phase transition and compute the expectation value of the resulting scalar operators in the low energy phase.Comment: 11 pages, 6 figure

    Lumpy AdS5×\bf{_5\times} S5\bf{^5} Black Holes and Black Belts

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    Sufficiently small Schwarzschild black holes in global AdS5×_5\timesS5^5 are Gregory-Laflamme unstable. We construct new families of black hole solutions that bifurcate from the onset of this instability and break the full SO(6)(6) symmetry group of the S5^5 down to SO(5)(5). These new "lumpy" solutions are labelled by the harmonics ℓ\ell. We find evidence that the ℓ=1\ell = 1 branch never dominates the microcanonical/canonical ensembles and connects through a topology-changing merger to a localised black hole solution with S8^8 topology. We argue that these S8^8 black holes should become the dominant phase in the microcanonical ensemble for small enough energies, and that the transition to Schwarzschild black holes is first order. Furthermore, we find two branches of solutions with ℓ=2\ell = 2. We expect one of these branches to connect to a solution containing two localised black holes, while the other branch connects to a black hole solution with horizon topology S4×S4\mathrm S^4\times\mathrm S^4 which we call a "black belt".Comment: 20 pages (plus 17 pages for Appendix on Kaluza-Klein Holography), 14 figure

    Application of remote sensing to selected problems within the state of California

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    Specific case studies undertaken to demonstrate the usefulness of remote sensing technology to resource managers in California are highlighted. Applications discussed include the mapping and quantization of wildland fire fuels in Mendocino and Shasta Counties as well as in the Central Valley; the development of a digital spectral/terrain data set for Colusa County; the Forsythe Planning Experiment to maximize the usefulness of inputs from LANDSAT and geographic information systems to county planning in Mendocino County; the development of a digital data bank for Big Basin State Park in Santa Cruz County; the detection of salinity related cotton canopy reflectance differences in the Central Valley; and the surveying of avocado acreage and that of other fruits and nut crops in Southern California. Special studies include the interpretability of high altitude, large format photography of forested areas for coordinated resource planning using U-2 photographs of the NASA Bucks Lake Forestry test site in the Plumas National Forest in the Sierra Nevada Mountains

    Application of remote sensing to selected problems within the state of California

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    There are no author-identified significant results in this report

    Agricultural interpretation technique development

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    There are no author-identified significant results in this report

    Design of an Automatic Traffic Control System with Real Time Vehicle Density Analysis

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    Growth in developing countries forcefully leads their roads becoming increasingly congested thus bringing traffic to a standstill. There are two major measures that can address this issue viz. manual and automatic approaches. Because of its inefficiency, manual approach is not considered under the preview of this study and the automatic approach, which is the focus of this study, can further be classified into two viz. timer based and density based approaches. Timer based approaches are primarily static in nature and hence cannot consider real time requirements. Incorporating Density analysis on to the problem under preview adds dynamism to the solution and in the proposed study, traffic signals are controlled by considering real time density of vehicles on each roads. After capturing real time images and performing appropriate preprocessing, density of vehicles are measured using Canny Edge detection approach; which is used as a parameter for later decision making. Considering density parameters alone may lead to starvation to certain roads and here in the proposed study, authors consider a weight factor to propose a better solution. A prototype was developed using Arduino mega 2560 board, Webcams and Airplane 9g Mini Servo - SG-90 and led lights and it was observed that the efficacy of the proposed system is higher while comparing it to other prevailing methods

    Combined Hazard Analyses to Explore the Impact of Liquid Hydrogen Fuel on the Civil Aviation Industry

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    Interest in green technology in aviation is increasing. To address environmental issues, novel fuels such as cryogenic liquid hydrogen (LH2) are being explored, however there are safety concerns. This work combines safety studies to explore LH2 fuel safety for civil aviation. Preliminary hazard analyses (PHAs) (utilizing over 70 standards and guides) have been performed identifying possible LH2 hazards on-board aircraft. A PHA has also been produced, with industry stakeholder involvement, to understand the major concerns for LH2 use at airports. Gaps in fundamental knowledge and LH2 technology have been identified, and two of these explored. Firstly, work has been started to understand the fundamental flammability of hydrogen in altitude conditions. Secondly, FLACS CFD modelling has been used to simulate large-scale LH2 pool releases to examine behavior and predict pool size, downwind flammable regions, and flammable mass clouds formed for different environmental conditions and release scenarios. This has identified significant effects of wind speed on buoyancy and flammable cloud travel which must be taken into account of any hydrogen fuel facility design. This work (part of the EC funded ENABLEH2 project) is some of the first in over a decade to re-examine the safety of hydrogen propulsion in aircraft. This process has identified wide-ranging issues that must be addressed before hydrogen propulsion can be introduced in civil aviation

    Parameter estimators of random intersection graphs with thinned communities

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    This paper studies a statistical network model generated by a large number of randomly sized overlapping communities, where any pair of nodes sharing a community is linked with probability qq via the community. In the special case with q=1q=1 the model reduces to a random intersection graph which is known to generate high levels of transitivity also in the sparse context. The parameter qq adds a degree of freedom and leads to a parsimonious and analytically tractable network model with tunable density, transitivity, and degree fluctuations. We prove that the parameters of this model can be consistently estimated in the large and sparse limiting regime using moment estimators based on partially observed densities of links, 2-stars, and triangles.Comment: 15 page

    Automated Grain Yield Behavior Classification

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    A method for classifying grain stress evolution behaviors using unsupervised learning techniques is presented. The method is applied to analyze grain stress histories measured in-situ using high-energy X-ray diffraction microscopy (HEDM) from the aluminum-lithium alloy Al-Li 2099 at the elastic-plastic transition (yield). The unsupervised learning process automatically classified the grain stress histories into four groups: major softening, no work-hardening or softening, moderate work-hardening, and major work-hardening. The orientation and spatial dependence of these four groups are discussed. In addition, the generality of the classification process to other samples is explored

    The Role of Legal Services in the Antipoverty Program

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    Large-scale adaptive radiations might explain the runaway success of a minority of extant vertebrate clades. This hypothesis predicts, among other things, rapid rates of morphological evolution during the early history of major groups, as lineages invade disparate ecological niches. However, few studies of adaptive radiation have included deep time data, so the links between extant diversity and major extinct radiations are unclear. The intensively studied Mesozoic dinosaur record provides a model system for such investigation, representing an ecologically diverse group that dominated terrestrial ecosystems for 170 million years. Furthermore, with 10,000 species, extant dinosaurs (birds) are the most speciose living tetrapod clade. We assembled composite trees of 614-622 Mesozoic dinosaurs/birds, and a comprehensive body mass dataset using the scaling relationship of limb bone robustness. Maximum-likelihood modelling and the node height test reveal rapid evolutionary rates and a predominance of rapid shifts among size classes in early (Triassic) dinosaurs. This indicates an early burst niche-filling pattern and contrasts with previous studies that favoured gradualistic rates. Subsequently, rates declined in most lineages, which rarely exploited new ecological niches. However, feathered maniraptoran dinosaurs (including Mesozoic birds) sustained rapid evolution from at least the Middle Jurassic, suggesting that these taxa evaded the effects of niche saturation. This indicates that a long evolutionary history of continuing ecological innovation paved the way for a second great radiation of dinosaurs, in birds. We therefore demonstrate links between the predominantly extinct deep time adaptive radiation of non-avian dinosaurs and the phenomenal diversification of birds, via continuing rapid rates of evolution along the phylogenetic stem lineage. This raises the possibility that the uneven distribution of biodiversity results not just from large-scale extrapolation of the process of adaptive radiation in a few extant clades, but also from the maintenance of evolvability on vast time scales across the history of life, in key lineages
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