3,627 research outputs found

    Investigation of the feasibility of sterile assembly of silver-zinc batteries

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    Electrical performance, bioassays, and packaging concepts evaluated in sterile assembly of silver zinc batterie

    Finite size corrections to the radiation reaction force in classical electrodynamics

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    We introduce an effective field theory approach that describes the motion of finite size objects under the influence of electromagnetic fields. We prove that leading order effects due to the finite radius RR of a spherically symmetric charge is order R2R^2 rather than order RR in any physical model, as widely claimed in the literature. This scaling arises as a consequence of Poincar\'e and gauge symmetries, which can be shown to exclude linear corrections. We use the formalism to calculate the leading order finite size correction to the Abraham-Lorentz-Dirac force.Comment: 4 pages, 2 figure

    High Energy Field Theory in Truncated AdS Backgrounds

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    In this letter we show that, in five-dimensional anti-deSitter space (AdS) truncated by boundary branes, effective field theory techniques are reliable at high energy (much higher than the scale suggested by the Kaluza-Klein mass gap), provided one computes suitable observables. We argue that in the model of Randall and Sundrum for generating the weak scale from the AdS warp factor, the high energy behavior of gauge fields can be calculated in a {\em cutoff independent manner}, provided one restricts Green's functions to external points on the Planck brane. Using the AdS/CFT correspondence, we calculate the one-loop correction to the Planck brane gauge propagator due to charged bulk fields. These effects give rise to non-universal logarithmic energy dependence for a range of scales above the Kaluza-Klein gap.Comment: LaTeX, 7 pages; minor typos fixe

    Degeneration and impaired regeneration of gray matter oligodendrocytes in amyotrophic lateral sclerosis.

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    Oligodendrocytes associate with axons to establish myelin and provide metabolic support to neurons. In the spinal cord of amyotrophic lateral sclerosis (ALS) mice, oligodendrocytes downregulate transporters that transfer glycolytic substrates to neurons and oligodendrocyte progenitors (NG2(+) cells) exhibit enhanced proliferation and differentiation, although the cause of these changes in oligodendroglia is unknown. We found extensive degeneration of gray matter oligodendrocytes in the spinal cord of SOD1 (G93A) ALS mice prior to disease onset. Although new oligodendrocytes were formed, they failed to mature, resulting in progressive demyelination. Oligodendrocyte dysfunction was also prevalent in human ALS, as gray matter demyelination and reactive changes in NG2(+) cells were observed in motor cortex and spinal cord of ALS patients. Selective removal of mutant SOD1 from oligodendroglia substantially delayed disease onset and prolonged survival in ALS mice, suggesting that ALS-linked genes enhance the vulnerability of motor neurons and accelerate disease by directly impairing the function of oligodendrocytes

    A nonlinear scalar model of extreme mass ratio inspirals in effective field theory I. Self force through third order

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    The motion of a small compact object in a background spacetime is investigated in the context of a model nonlinear scalar field theory. This model is constructed to have a perturbative structure analogous to the General Relativistic description of extreme mass ratio inspirals (EMRIs). We apply the effective field theory approach to this model and calculate the finite part of the self force on the small compact object through third order in the ratio of the size of the compact object to the curvature scale of the background (e.g., black hole) spacetime. We use well-known renormalization methods and demonstrate the consistency of the formalism in rendering the self force finite at higher orders within a point particle prescription for the small compact object. This nonlinear scalar model should be useful for studying various aspects of higher-order self force effects in EMRIs but within a comparatively simpler context than the full gravitational case. These aspects include developing practical schemes for higher order self force numerical computations, quantifying the effects of transient resonances on EMRI waveforms and accurately modeling the small compact object's motion for precise determinations of the parameters of detected EMRI sources.Comment: 30 pages, 8 figure

    On Writ of Certiorari to the United States Court of Appeals for the Ninth Circuit, Brief of Product Liability Advisory Council, Inc., National Association of Manufacturers, Business Roundtable, and Chemical Manufacturers Association as Amici Curiae in Support of Respondent, William Daubert and Joyce Daubert, Individually and as Guardians Ad Litem for Jason Daubert, and Anita De Young, Individually and as Gaurdian Ad Litem for Eric Schuller v. Merrell Dow Pharmaceuticals, Inc.

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    The Federal Rules of Evidence exclude expert scientific testimony when it has been developed without regard for accepted scientific methods. This case focuses on expert scientific evidence. Such evidence plays a vital and often dispositive role in modern litigation. For scientific evidence to be helpful to the factfinder it must meet some minimal threshold of reliability. To hold otherwise would be to allow a system of adjudication based more on chance than on reason

    Next to leading order spin-orbit effects in the motion of inspiralling compact binaries

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    Using effective field theory (EFT) techniques we calculate the next-to-leading order (NLO) spin-orbit contributions to the gravitational potential of inspiralling compact binaries. We use the covariant spin supplementarity condition (SSC), and explicitly prove the equivalence with previous results by Faye et al. in arXiv:gr-qc/0605139. We also show that the direct application of the Newton-Wigner SSC at the level of the action leads to the correct dynamics using a canonical (Dirac) algebra. This paper then completes the calculation of the necessary spin dynamics within the EFT formalism that will be used in a separate paper to compute the spin contributions to the energy flux and phase evolution to NLO.Comment: 25 pages, 4 figures, revtex4. v2: minor changes, refs. added. To appear in Class. Quant. Gra

    Casimir effect in de Sitter and Anti-de Sitter braneworlds

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    We discuss the bulk Casimir effect (effective potential) for a conformal or massive scalar when the bulk represents five-dimensional AdS or dS space with two or one four-dimensional dS brane, which may correspond to our universe. Using zeta-regularization, the interesting conclusion is reached, that for both bulks in the one-brane limit the effective potential corresponding to the massive or to the conformal scalar is zero. The radion potential in the presence of quantum corrections is found. It is demonstrated that both the dS and the AdS braneworlds may be stabilized by using the Casimir force only. A brief study indicates that bulk quantum effects are relevant for brane cosmology, because they do deform the de Sitter brane. They may also provide a natural mechanism yielding a decrease of the four-dimensional cosmological constant on the physical brane of the two-brane configuration.Comment: 37 pages, LaTeX, references added, some revision is done, version to appear in PR

    New Upper Limits on the Tau Neutrino Mass from Primordial Helium Considerations

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    In this paper we reconsider recently derived bounds on MeVMeV tau neutrinos, taking into account previously unaccounted for effects. We find that, assuming that the neutrino life-time is longer than O(100 sec)O(100~sec), the constraint Neff<3.6N_{eff}<3.6 rules out ντ\nu_{\tau} masses in the range 0.5 (MeV)<mντ<35 (MeV)0.5~(MeV)<m_{\nu_\tau}<35~(MeV) for Majorana neutrinos and 0.74 (MeV)<mντ<35 (MeV)0.74~(MeV)<m_{\nu_\tau}<35~(MeV) for Dirac neutrinos. Given that the present laboratory bound is 35 MeV, our results lower the present bound to 0.50.5 and 0.740.74 for Majorana and Dirac neutrinos respectively.Comment: 9 pages (2 figures available upon request), UM-AC-93-0
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