55,253 research outputs found

    Holographic Geometry and Noise in Matrix Theory

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    Using Matrix Theory as a concrete example of a fundamental holographic theory, we show that the emergent macroscopic spacetime displays a new macroscopic quantum structure, holographic geometry, and a new observable phenomenon, holographic noise, with phenomenology similar to that previously derived on the basis of a quasi-monochromatic wave theory. Traces of matrix operators on a light sheet with a compact dimension of size RR are interpreted as transverse position operators for macroscopic bodies. An effective quantum wave equation for spacetime is derived from the Matrix Hamiltonian. Its solutions display eigenmodes that connect longitudinal separation and transverse position operators on macroscopic scales. Measurements of transverse relative positions of macroscopically separated bodies, such as signals in Michelson interferometers, are shown to display holographic nonlocality, indeterminacy and noise, whose properties can be predicted with no parameters except RR. Similar results are derived using a detailed scattering calculation of the matrix wavefunction. Current experimental technology will allow a definitive and precise test or validation of this interpretation of holographic fundamental theories. In the latter case, they will yield a direct measurement of RR independent of the gravitational definition of the Planck length, and a direct measurement of the total number of degrees of freedom.Comment: 19 pages, 2 figures; v2: factors of Planck mass written explicitly, typos correcte

    Post-weaning performance and carcass characteristics of steer progency from different suckler cow breed types

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    peer-reviewedIn two experiments a total of 44 steer progeny of spring-calving Charolais (C) and Hereford × Friesian (HF) suckler cows and C sires were slaughtered at approximately 2 years of age. Following weaning they were offered silage and 1 kg of concentrate per head daily during a 5 month winter after which they spent 7 months at pasture. In Experiment 1, animals were given a silage/concentrate diet during a finishing period of either 95 or 152 days. In Experiment 2, steers were offered either a daily diet of silage plus 6 kg of concentrates or concentrates to appetite plus 5 kg of silage (fresh weight) during the final 140-day finishing period. Following slaughter, an 8-rib pistola from each animal was dissected. For the two experiments combined C and HF progeny had carcass weights of 372 and 385 (s.e. 6.1) kg, proportions of carcass as pistola of 467 and 454 (s.e. 2.8) g/kg and pistola meat proportions of 676 and 642 (s.e. 5.1) g/kg, respectively. All fat traits were lower for the C than HF progeny but there was no difference in carcass conformation score. Increasing slaughter weight increased carcass weight (P < 0.001), kidney plus channel fat weight (P < 0.001), and pistola fat proportion (P < 0.001) and decreased the proportions of carcass as pistola (P < 0.05), pistola meat (P < 0.01), and bone (P < 0.05). In conclusion, breed type had no effect on carcass growth but the C progeny had higher meat yield than the HF. Increasing slaughter weight increased fatness and reduced meat yield

    Helically symmetric N-particle solutions in scalar gravity

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    Within a scalar model theory of gravity, where the interaction between particles is given by the half-retarded + half-advanced solution of the scalar wave equation, we consider an N-body problem: we investigate configurations of N particles which form an equilateral N-angle and are in helical motion about their common center. We prove that there exists a unique equilibrium configuration and compute the equilibrium radius explicitly in a post-Newtonian expansion.Comment: 5 pages, 1 figure; minor corrections and changes; accepted for publication in Physical Review Letter

    Dust in regions of massive star formation

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    It is suggested that protostars increase mass by accreting the surrounding gas and dust. Grains are destroyed as they near the central protostar creating a dust shell or cocoon. Radiation pressure acting on the grains can halt the inflow of material thereby limiting the amount of mass accumulated by the protostar. General constraints were considered on the initial dust-to-gas ratio and mass accretion rates that permit inflow. These results were constrained further by constructing a numerical model, including radiative deceleration on grains and grain destruction processes. Also the constraints on dust properties were investigated which allow the formation of massive stars. The obtained results seem to suggest that massive star formation requires rather extreme preconditioning of the grain and gas environment

    Detection of Hemlock Woolly Adelgid (Hemiptera: Adelgidae) Infestations with Sticky Traps

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    We deployed sticky traps underneath the crown of eastern hemlock, Tsuga canadensis (L.) Carrière, to assess their sensitivity at detecting crawlers (1st instar nymphs) of the non-native hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae). We found these traps more sensitive at detecting infested trees with low densities of A. tsugae than branch-tip sampling with pole pruners. We observed two peaks of crawler abundance at all sites: these peaks likely represented the timing of the progrediens and sistens crawler stages of A. tsugae. Deployment of sticky traps in treated and high-risk stands may prove useful at detecting residual and new infestations, respectively
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