17,670 research outputs found

    State Public Nuisance Claims and Climate Change Adaptation

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    This Article explores the potential for state public nuisance claims to facilitate adaptation, resource protection, and other climate change responses by coastal communities in California. The California public nuisance actions represent just the latest chapter in efforts to spur responses to climate change and attribute responsibility for climate change through the common law. Part II of this Article describes the California public nuisance lawsuits and situates them in the context of common law actions directed against climate change. Part III considers the preliminary defenses that defendants have raised and could raise in the California public nuisance lawsuits, including the existence of state common law in this context, separation of powers and the political question doctrine, displacement and preemption, and standing. Part IV considers the potential merits of the plaintiffs’ public nuisance claims under California law

    Adiabatic self-tuning in a silicon microdisk optical resonator

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    We demonstrate a method for adiabatically self-tuning a silicon microdisk resonator. This mechanism is not only able to sensitively probe the fast nonlinear cavity dynamics, but also provides various optical functionalities like pulse compression, shaping, and tunable time delay

    A proposal for highly tunable optical parametric oscillation in silicon micro-resonators

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    We propose a novel scheme for continuous-wave pumped optical parametric oscillation (OPO) inside silicon micro-resonators. The proposed scheme not only requires a relative low lasing threshold, but also exhibits extremely broad tunability extending from the telecom band to mid infrared

    A PI3K-mediated negative feedback regulates Drosophila motor neuron excitability

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    Negative feedback can act as a homeostatic mechanism to maintain neuronal activity at a particular specified value. At the Drosophila neuromuscular junction, a mutation in the type II metabotropic glutamate receptor gene (mGluRA) increased motor neuron excitability by disrupting an autocrine, glutamate-mediated negative feedback. We show that mGluRA mutations increase neuronal excitability by preventing PI3 kinase (PI3K) activation and consequently hyperactivating the transcription factor Foxo. Furthermore, glutamate application increases levels of phospho-Akt, a product of PI3K signaling, within motor nerve terminals in an mGluRA-dependent manner. In humans, PI3K and type II mGluRs are implicated in epilepsy, neurofibromatosis, autism, schizophrenia and other neurological disorders; however, neither the link between type II mGluRs and PI3K, nor the role of Foxo in the control of neuronal excitability, had been previously reported. Our work suggests that some of the deficits in these neurological disorders might result from disruption of glutamate-mediated homeostasis of neuronal excitability

    Final spins from the merger of precessing binary black holes

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    The inspiral of binary black holes is governed by gravitational radiation reaction at binary separations r < 1000 M, yet it is too computationally expensive to begin numerical-relativity simulations with initial separations r > 10 M. Fortunately, binary evolution between these separations is well described by post-Newtonian equations of motion. We examine how this post-Newtonian evolution affects the distribution of spin orientations at separations r ~ 10 M where numerical-relativity simulations typically begin. Although isotropic spin distributions at r ~ 1000 M remain isotropic at r ~ 10 M, distributions that are initially partially aligned with the orbital angular momentum can be significantly distorted during the post-Newtonian inspiral. Spin precession tends to align (anti-align) the binary black hole spins with each other if the spin of the more massive black hole is initially partially aligned (anti-aligned) with the orbital angular momentum, thus increasing (decreasing) the average final spin. Spin precession is stronger for comparable-mass binaries, and could produce significant spin alignment before merger for both supermassive and stellar-mass black hole binaries. We also point out that precession induces an intrinsic accuracy limitation (< 0.03 in the dimensionless spin magnitude, < 20 degrees in the direction) in predicting the final spin resulting from the merger of widely separated binaries.Comment: 20 pages, 16 figures, new PN terms, submitted to PR

    Origin of large moments in Mnx_xSi1x_{1-x} at small x

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    Recently, the magnetic moment/Mn, MM, in Mnx_xSi1x_{1-x} was measured to be 5.0 μB\mu_B/Mn, at xx =0.1%. To understand this observed MM, we investigate several Mnx_xSi1x_{1-x} models of alloys using first-principles density functional methods. The only model giving M=5.0M = 5.0 was a 513-atom cell having the Mn at a substitutional site, and Si at a second-neighbor interstitial site. The observed large moment is a consequence of the weakened d-p hybridization between the Mn and one of its nearest neighbor Si atoms, resulting from the introduction of the second-neighbor interstitial Si. Our result suggests a way to tune the magnetic moments of transition metal doped semiconductors.Comment: 4 pages, 2 figure

    Hybrid meson decay from the lattice

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    We discuss the allowed decays of a hybrid meson in the heavy quark limit. We deduce that an important decay will be into a heavy quark non-hybrid state and a light quark meson, in other words, the de-excitation of an excited gluonic string by emission of a light quark-antiquark pair. We discuss the study of hadronic decays from the lattice in the heavy quark limit and apply this approach to explore the transitions from a spin-exotic hybrid to χbη\chi_b \eta and χbS\chi_b S where SS is a scalar meson. We obtain a signal for the transition emitting a scalar meson and we discuss the phenomenological implications.Comment: 18 pages, LATEX, 3 ps figure
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