2,227 research outputs found

    An accounting evaluation of user cost of capital for French firms: 1984-2002

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    This work presents a methodology to evaluate user cost of capital using firm level accounting data for French firms between 1984 and 2002. This evaluation relies on a modelling of individual user cost of capital that accounts for the structure of the financing of the firm, banking interest rates and the taxation of firms and shareholders. The model used in the paper comes from Crépon, Gianella (2001) and is inspired from Jorgenson (1963) and Auerbach (1983). We insist on the fact that the cost to use some capital actually depends on the nature of the assets that will be financed. The evaluation should then fit with the question at issue. Finally, the contribution of the paper is to use firm or sector level data each time these are available. Thus, the evaluation relies on an individual estimation of the taxation of benefits and uses sectorial life spans of capital computed by Picart (2004).User cost of capital, taxation, firm level data

    Dynamic behaviour of an asymmetric building: Experimental and numerical studies

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    AbstractThe paper presents a study on the seismic assessment of a 21-story building having an asymmetrical plan. The study applies the approach using in-situ measurements to assess the building's seismic performance. According to preliminary observations on site, the soil may have a significant influence on the building's behaviour. That is why it is important to isolate the behaviour of the building from the soil effect (fixed-base structure). First, in-situ dynamic measurements are conducted to identify dynamic characteristics of the building. The Frequency Domain Decomposition (FDD) method is used to determine the vibration modes of the building in three dimensions (3D). First three vibration modes with close frequencies and unusual mode shapes were identified, which shows the relevance of the used method in the case of buildings having complex behaviour. Second, the relevance of the applied approach was checked by using 3D Finite Element (FE) modelling, in both cases: fixed-base structure and soil + structure system

    Why Are Caribou Declining in the Oil Sands?

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    Resonance fluorescence from an artificial atom in squeezed vacuum

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    We present an experimental realization of resonance fluorescence in squeezed vacuum. We strongly couple microwave-frequency squeezed light to a superconducting artificial atom and detect the resulting fluorescence with high resolution enabled by a broadband traveling-wave parametric amplifier. We investigate the fluorescence spectra in the weak and strong driving regimes, observing up to 3.1 dB of reduction of the fluorescence linewidth below the ordinary vacuum level and a dramatic dependence of the Mollow triplet spectrum on the relative phase of the driving and squeezed vacuum fields. Our results are in excellent agreement with predictions for spectra produced by a two-level atom in squeezed vacuum [Phys. Rev. Lett. \textbf{58}, 2539-2542 (1987)], demonstrating that resonance fluorescence offers a resource-efficient means to characterize squeezing in cryogenic environments

    Spatial patterning of prey at reproduction to reduce predation risk: what drives dispersion from groups?

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    Group living is a widespread behavior thought to be an evolutionary adaptation for reducing predation risk. Many group-living species, however, spend a portion of their life cycle as dispersed individuals, suggesting that the costs and benefits of these opposing behaviors vary temporally. Here, we evaluated mechanistic hypotheses for explaining individual dispersion as a tactic for reducing predation risk at reproduction (i.e., birthing) in an otherwise group-living animal. Using simulation analyses parameterized by empirical data, we assessed whether dispersion increases reproductive success by (i) increasing predator search time, (ii) reducing predator encounter rates because individuals are inconspicuous relative to groups, or (iii) eliminating the risk of multiple kills per encounter. Simulations indicate that dispersion becomes favorable only when detectability increases with group size and there is risk of multiple kills per encounter. This latter effect, however, is likely the primary mechanism driving females to disperse at reproduction because group detectability effects are presumably constant year-round. We suggest that the risk of multiple kills imposed by highly vulnerable offspring may be an important factor influencing dispersive behavior in many species, and conservation strategies for such species will require protecting sufficient space to allow dispersion to effectively reduce predation risk

    Measurement-induced qubit state mixing in circuit QED from up-converted dephasing noise

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    We observe measurement-induced qubit state mixing in a transmon qubit dispersively coupled to a planar readout cavity. Our results indicate that dephasing noise at the qubit-readout detuning frequency is up-converted by readout photons to cause spurious qubit state transitions, thus limiting the nondemolition character of the readout. Furthermore, we use the qubit transition rate as a tool to extract an equivalent flux noise spectral density at f ~ 1 GHz and find agreement with values extrapolated from a 1/fα1/f^\alpha fit to the measured flux noise spectral density below 1 Hz.Comment: 5 pages, 4 figures. Final journal versio

    Tactics for Reasoning modulo AC in Coq

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    We present a set of tools for rewriting modulo associativity and commutativity (AC) in Coq, solving a long-standing practical problem. We use two building blocks: first, an extensible reflexive decision procedure for equality modulo AC; second, an OCaml plug-in for pattern matching modulo AC. We handle associative only operations, neutral elements, uninterpreted function symbols, and user-defined equivalence relations. By relying on type-classes for the reification phase, we can infer these properties automatically, so that end-users do not need to specify which operation is A or AC, or which constant is a neutral element.Comment: 16

    Comparative evaluation of three TSPO PET radiotracers in a LPS-induced model of mild neuroinflammation in rats.

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    PURPOSE: Over the past 20 years, neuroinflammation (NI) has increasingly been recognised as having an important role in  many neurodegenerative diseases, including Alzheimer's disease. As such, being able to image NI non-invasively in patients is critical to monitor pathological processes and potential therapies targeting neuroinflammation. The translocator protein (TSPO) has proven a reliable NI biomarker for positron emission tomography (PET) imaging. However, if TSPO imaging in acute conditions such as stroke provides strong and reliable signals, TSPO imaging in neurodegenerative diseases has proven more challenging. Here, we report results comparing the recently developed TSPO tracers [(18)F]GE-180 and [(18)F]DPA-714 with (R)-[(11)C]PK11195 in a rodent model of subtle focal inflammation. PROCEDURES: Adult male Wistar rats were stereotactically injected with 1 μg lipopolysaccharide in the right striatum. Three days later, animals underwent a 60-min PET scan with (R)-[(11)C]PK11195 and [(18)F]GE-180 (n = 6) or [(18)F]DPA-714 (n = 6). Ten animals were scanned with either [(18)F]GE-180 (n = 5) or [(18)F]DPA-714 (n = 5) only. Kinetic analysis of PET data was performed using the simplified reference tissue model (SRTM) with a contralateral reference region or a novel data-driven input to estimate binding potential BPND. Autoradiography and immunohistochemistry were performed to confirm in vivo results. RESULTS: At 40-60 min post-injection, [(18)F]GE-180 dual-scanned animals showed a significantly increased core/contralateral uptake ratio vs. the same animals scanned with (R)-[(11)C]PK11195 (3.41 ± 1.09 vs. 2.43 ± 0.39, p = 0.03); [(18)]DPA-714 did not (2.80 ± 0.69 vs. 2.26 ± 0.41). Kinetic modelling with a contralateral reference region identified significantly higher binding potential (BPND) in the core of the LPS injection site with [(18)F]GE-180 but not with [(18)F]DPA-714 vs. (R)-[(11)C]PK11195. A cerebellar reference region and novel data-driven input to the SRTM were unable to distinguish differences in tracer BPND. CONCLUSIONS: Second-generation TSPO-PET tracers are able to accurately detect mild-level NI. In this model, [(18)F]GE-180 shows a higher core/contralateral ratio and BPND when compared to (R)-[(11)C]PK11195, while [(18)F]DPA-714 did not
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