7,479 research outputs found

    Micropropagation of Ailanthus altissima and in vitro heavy metal tolerance

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    Ailanthus altissima, a fast?growing and contamination?resistant species is investigated for its use in areas contaminated by heavy metals. A micropropagation protocol for A. altissima was developed, cultured shoots were tested for in vitro heavy metals tolerance. Proliferation rate and shoot length were affected by 6?benzylaminopurine (BAP) and Murashige and Skoog\u27s (MS) salt concentrations, best results were obtained in full strength MS medium supplemented with 1.32 or 2.64 μM BAP. Rooting percentage was strongly influenced by indole?3?butyric acid. Cultures of A. altissima exposed to heavy metals demonstrated a tolerance comparable to species already utilized in phytoremediation

    Dimensionality of the spatio-temporal entanglement of PDC photon pairs

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    In this work the Schmidt number of the two-photon state generated by parametric-down conversion (PDC) is evaluated in the framework of a fully spatio-temporal model for PDC. A comparison with the results obtained in either purely spatial or purely temporal models shows that the degree of entanglement of the PDC state cannot be trivially reduced to the product of the Schmidt numbers obtained in models with lower dimensionality, unless the detected bandwidth is very narrow. This result is a consequence of the non-factorability of the state in the spatial and temporal degrees of freedoms of twin photons. In the limit of a broad pump beam, we provide a geometrical interpretation of the Schmidt number, as the ratio between the volume of the phase matching region and of a correlation volume.Comment: 17 pages, 10 figures. Submitted to Phys. Rev.

    Experimental observation of the X-shaped near field spatio-temporal correlation of ultra-broadband twin beams

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    In this work we present the experimental observation of the non factorable near field spatio-temporal correlation of ultra-broadband twin beams generated by parametric down conversion (PDC), in an interferometric-type experiment using sum frequency generation, where both the temporal and spatial degrees of freedom of PDC light are controlled with very high resolution. The revealed X-structure of the correlation is in accordance with the predictions of the theory.Comment: 5 pages, 3 figure

    The synthesis of boron carbide filaments final report

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    Synthesis, strength, crystal structure, and composite material formation of boron carbide whisker

    High-sensitivity imaging with multi-mode twin beams

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    Twin entangled beams produced by single-pass parametric down-conversion (PDC) offer the opportunity to detect weak amount of absorption with an improved sensitivity with respect to standard techniques which make use of classical light sources. We propose a differential measurement scheme which exploits the spatial quantum correlation of type II PDC to image a weak amplitude object with a sensitivity beyond the standard quantum limit imposed by shot-noise.Comment: 13 pages, 8 figure

    "Credit Cycle" in an OLG Economy with Money and Bequest

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    In the late '90s Kiyotaki and Moore (KM) put forward a new framework (Kiyotaki and Moore,1997) to explore the Financial Accelerator hypothesis. The original model was framed in an Infinitely Lived Agent context (ILA-KM economy). As in KM we develop a dynamic model in which the durable asset ("land") is not only an input but also collateralizable wealth to secure lenders from the risk of borrowers' default. In this paper, however, we model an OLG-KM economy whose novel feature is the role of money as a store of value and of bequest as a vehicle of resources to be "invested" in landholding. The dynamics generated by the model are complex. Not only cyclical patterns are routinely generated but the periodicity and amplitude are irregular. A route to chaotic dynamics is open.
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