22,372 research outputs found

    The refractivity of Co sub 2 under simulated martian conditions

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    Refractivity of carbon dioxide under simulated Martian conditions by radio occulatio

    Rhinologic changes in Wegener's granulomatosis

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    Twenty-eight patients with a clinical diagnosis of sinonasal Wegener's granulomatosis were referred for imaging during the period 1990-2001. Of these, 10 had clinical symptoms and signs confined to the nose and sinuses and 18 had classical systemic Wegener's. The computed tomography (CT) and magnetic resonance (MRI) scans of the series were reviewed by a panel of one otolaryngologist and two radiologists. From the total of 28 patients, 85.7 per cent showed non-specific mucosal thickening in the nasal cavity or paranasal sinuses, 75 per cent showed evidence of bone destruction, and 50 per cent new bone formation in the walls of the sinus cavities. In addition the orbit was affected in 30 per cent of patients.The diagnosis of systemic Wegener's granulomatosis is made clinically but the condition may present characteristic features on imaging by CT and MRI. In a patient without a history of previous sinonasal surgery, a combination of bone destruction and new bone formation on CT is virtually diagnostic of Wegener's especially when accompanied on MRI by a fat signal from the sclerotic sinus wall. These changes are important diagnostically in localized sinonasal Wegener's granulomatosis where the clinical diagnosis may be uncertain and the cANCA test can be negative

    Profiting from Regulation: An Event Study of the EU Carbon Market

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    We investigate the effect of cap-and-trade regulation of CO2 on firm profits by performing an event study of a CO2 price crash in the EU market. We examine returns for 90 stocks from carbon intensive industries and 600 stocks in the broad EUROSTOXX index. Firms in carbon intensive, or electricity intensive industries, but not involved in international trade were most hurt by the event. �This implies investors were focused on product price impacts, rather than compliance costs. We find evidence that firms’ net allowance positions also strongly influenced the share price response to the decline in allowance prices.Emissions Markets; Incidence of Taxation; Event Study

    Profiting from Regulation: An Event Study of the EU Carbon Market

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    Tradable permit regulations have recently been implemented for climate change policy in many countries. One of the first mandatory markets was the EU Emission Trading System, whose first phase ran from 2005-07. Unlike taxes, permits expose firms to volatility in regulatory costs, but are typically accompanied by property rights in the form of grandfathered permits. In this paper, we examine the effect of this type of environmental regulation on profits. In particular, changes in permit prices affect: (1) the direct and indirect input costs, (2) output revenue, and (3) the carbon permit asset value. Depending on abatement costs, output price sensitivity, and permit allocation, these effects may vary considerably across industries and firms. We run an event study of the carbon price crash on April 25, 2006 by examining the daily stock returns for 90 stocks from carbon intensive industries and approximately 600 stocks in the broad EUROSTOXX index. In general, firms in industries that tended to be either carbon intensive, or electricity intensive, but not involved in international trade, were hurt by the decline in permit prices. In industries that were known to be net short of permits, the cleanest firms saw the largest declines in share value. In industries known to be long in permits, firms granted the largest allocations were most harmed.

    Bulk-driven non-equilibrium phase transitions in a mesoscopic ring

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    We study a periodic one-dimensional exclusion process composed of a driven and a diffusive part. In a mesoscopic limit where both dynamics compete we identify bulk-driven phase transitions. We employ mean-field theory complemented by Monte-Carlo simulations to characterize the emerging non-equilibrium steady states. Monte-Carlo simulations reveal interesting correlation effects that we explain phenomenologically.Comment: 4 pages, 3 figure

    Generation of mechanical interference fringes by multi-photon counting

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    Exploring the quantum behaviour of macroscopic objects provides an intriguing avenue to study the foundations of physics and to develop a suite of quantum-enhanced technologies. One prominent path of study is provided by quantum optomechanics which utilizes the tools of quantum optics to control the motion of macroscopic mechanical resonators. Despite excellent recent progress, the preparation of mechanical quantum superposition states remains outstanding due to weak coupling and thermal decoherence. Here we present a novel optomechanical scheme that significantly relaxes these requirements allowing the preparation of quantum superposition states of motion of a mechanical resonator by exploiting the nonlinearity of multi-photon quantum measurements. Our method is capable of generating non-classical mechanical states without the need for strong single photon coupling, is resilient against optical loss, and offers more favourable scaling against initial mechanical thermal occupation than existing schemes. Moreover, our approach allows the generation of larger superposition states by projecting the optical field onto NOON states. We experimentally demonstrate this multi-photon-counting technique on a mechanical thermal state in the classical limit and observe interference fringes in the mechanical position distribution that show phase superresolution. This opens a feasible route to explore and exploit quantum phenomena at a macroscopic scale.Comment: 16 pages, 4 figures. v1: submitted for review on 28 Jan 2016. v2: significantly revised manuscript. v3: some further revisions and some extra results included. v3: new results added, extra author added, close to published version, supplementary material available with published versio

    Ion Charge States in Halo CMEs: What can we Learn about the Explosion?

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    We describe a new modeling approach to develop a more quantitative understanding of the charge state distributions of the ions of various elements detected in situ during halo Coronal Mass Ejection (CME) events by the Advanced Composition Explorer (ACE) satellite. Using a model CME hydrodynamic evolution based on observations of CMEs propagating in the plane of the sky and on theoretical models, we integrate time dependent equations for the ionization balance of various elements to compare with ACE data. We find that plasma in the CME ``core'' typically requires further heating following filament eruption, with thermal energy input similar to the kinetic energy input. This extra heating is presumably the result of post eruptive reconnection. Plasma corresponding to the CME ``cavity'' is usually not further ionized, since whether heated or not, the low density gives freeze-in close the the Sun. The current analysis is limited by ambiguities in the underlying model CME evolution. Such methods are likely to reach their full potential when applied to data to be acquired by STEREO when at optimum separation. CME evolution observed with one spacecraft may be used to interpret CME charge states detected by the other.Comment: 20 pages, accepted by Ap

    Twisted supersymmetry and the topology of theory space

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    We present examples of four dimensional, non-supersymmetric field theories in which ultraviolet supersymmetry breaking effects, such as bose-fermi splittings and the vacuum energy, are suppressed by (α/4π)N(\alpha/4 \pi)^{N}, where α\alpha is a weak coupling factor and NN can be made arbitrarily large. The particle content and interactions of these models are conveniently represented by a graph with sites and links, describing the gauge theory space structure. While the theories are supersymmetric ``locally'' in theory space, supersymmetry can be explicitly broken by topological obstructions.Comment: 9 pages, revtex
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