4,361 research outputs found

    Reply to ``Comment on `Test of constancy of speed of light with rotating cryogenic optical resonators' ''

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    An improved analysis of the Michelson-Morley-type experiment by P. Antonini et al. (Phys. Rev. A. 71, 050101 (2005)) yields the Robertson-Mansouri-Sexl theory parameter combination β−δ−1/2=(−0.6±2.1±1.2)⋅10−10\beta-\delta-1/2=(-0.6\pm 2.1\pm 1.2)\cdot10^{-10} and the Standard Model Extension theory parameter (κ~e−)ZZ=(−2.9±2.2)⋅10−14(\tilde{\kappa}_{e-})^{ZZ} = (-2.9\pm 2.2)\cdot 10^{-14}.Comment: 2 page

    An experimental apparatus for measuring the Casimir effect at large distances

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    An experimental set-up for the measurement of the Casimir effect at separations larger than a few microns is presented. The apparatus is based on a mechanical resonator and uses a homodyne detection technique to sense the Casimir force in the plane-parallel configuration. First measurements in the 3-10 micrometer range show an unexpected large force probably due to patch effects.Comment: Proceedings of the workshop On the 60 Years on Casimir Effec

    Parameterized model order reduction of delayed systems using an interpolation approach with amplitude and frequency scaling coefficients

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    When the geometric dimensions become electrically large or signal waveform rise times decrease, time delays must be included in the modeling. We present an innovative PMOR technique for neutral delayed differential systems, which is based on an efficient and reliable combination of univariate model order reduction methods, amplitude and frequency scaling coefficients and positive interpolation schemes. It is able to provide parameterized reduced order models passive by construction over the design space of interest. Pertinent numerical examples validate the proposed PMOR approach

    Test of constancy of speed of light with rotating cryogenic optical resonators

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    A test of Lorentz invariance for electromagnetic waves was performed by comparing the resonance frequencies of two optical resonators as a function of orientation in space. In terms of the Robertson-Mansouri-Sexl theory, we obtain β−δ−1/2=(+0.5±3±0.7)E−10\beta-\delta-1/2=(+0.5\pm 3\pm 0.7) E-10, a ten-fold improvement compared to the previous best results. We also set a first upper limit for a so far unknown parameter of the Standard Model Extension test theory, ∣(κ~e−)ZZ∣<2⋅E−14|(\tilde{\kappa}_{e-})^{ZZ}| < 2\cdot E-14.Comment: 4 pages, 2 figures, accepted for publication Phys. Rev. A (2005

    A cloud robotics architecture for an emergency management and monitoring service in a smart cityenvironment

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    Cloud robotics is revolutionizing not only the robotics industry but also the ICT world, giving robots more storage and computing capacity, opening new scenarios that blend the physical to the digital world. In this vision new IT architectures are required to manage robots, retrieve data from them and create services to interact with users. In this paper a possible implementation of a cloud robotics architecture for the interaction between users and UAVs is described. Using the latter as monitoring agents, a service for fighting crime in urban environment is proposed, making one step forward towards the idea of smart cit

    Antibacterial activity of matrix-bound ovotransferrin

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    Ovotransferrin immobilized by covalent linkage to Sepharose 4B showed a bacteriostatic effect towards Escherichia coli similar to that of free ovotransferrin. The growth of the bacteria, after exposure to the gel-bound ovotransferrin and its removal, depended on the length of exposure. The results suggest that the antibacterial activity of transferrin is not due simply to the removal of iron from the medium

    Agriculture, Profitability and Climate Change: Can Accounting Help Identify Best Farming Practices? Empirical Case Study in Spain

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    We perform an empirical analysis on the benefits of, and the challenges faced by, sustainability accounting in measuring the effects of climate change for a sample of Spanish rice farms. We use farm yields, revenues and incomes as indicators of economic performance, and greenhouse gas emissions, and direct and indirect energy consumption as indicators of climate change effects. According to our data, farms with higher yields, revenues and income are responsible for a greater environmental impact, measured in total gigajoules of energy consumed and tons of carbon dioxide emitted, than farms with a lower economic performance. Results show that in our sample the achievement of higher yields is attributable to the greater use of chemical inputs and fossil fuels and not to innovative and sustainable farming practices. The results indicate that accounting for climate change effects is not only possible but also necessary to provide more accurate information on the overall costs and benefits of farming. Greater transparency in accounting information should serve to highlight which farming activities are better able to reduce climate change impacts

    Thermostable Shelf Life Study

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    The objective of this project is to determine the shelf life end-point of various food items by means of actual measurement or mathematical projection. The primary goal of the Advanced Food Technology Project in these long duration exploratory missions is to provide the crew with a palatable, nutritious and safe food system while minimizing volume, mass, and waste. The Mars missions could be as long as 2.5 years with the potential of the food being positioned prior to the crew arrival. Therefore, it is anticipated that foods that are used during the Mars missions will require a 5 year shelf life. Shelf life criteria are safety, nutrition, and acceptability. Any of these criteria can be the limiting factor in determining the food's shelf life. Due to the heat sterilization process used for the thermostabilized food items, safety will be preserved as long as the integrity of the package is maintained. Nutrition and acceptability will change over time. Since the food can be the sole source of nutrition to the crew, a significant loss in nutrition may determine when the shelf life endpoint has occurred. Shelf life can be defined when the food item is no longer acceptable. Acceptability can be defined in terms of appearance, flavor, texture, or aroma. Results from shelf life studies of the thermostabilized food items suggest that the shelf life of the foods range from 0 months to 8 years, depending on formulation

    Rice farming, profitability and climate change. Can accounting help to identify best practices? Empirical case study in Spain

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    We perform an empirical analysis on the benefits of, and the challenges faced by, sustainability accounting in measuring the effects of climate change for a sample of Spanish rice farms. We use farm yields, revenues and incomes as indicators of economic performance, and greenhouse gas emissions, and direct and indirect energy consumption as indicators of climate change effects. According to our data, farms with higher yields, revenues and income are responsible for a greater environmental impact, measured in total gigajoules of energy consumed and tons of carbon dioxide emitted, than farms with a lower economic performance. Results show that in our sample the achievement of higher yields is attributable to the greater use of chemical inputs and fossil fuels and not to innovative and sustainable farming practices. The results indicate that accounting for climate change effects can provide useful information to reduce climate change impacts
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