42,434 research outputs found

    Chronicle of a Pandemic Foretold. CEPS Policy Insights No 2020-05 / March 2020

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    In just a few weeks, COVID-19 appeared in China and quickly spread to the rest of the world, including Europe and the United States. Many have rushed to describe the outbreak as a ‘black swan’ – an unpredictable event with extremely severe consequences. However, COVID-19 was not only predictable ex post: it was amply predicted ex ante. This allows us to draw some preliminary lessons: ‱ First, economic policy will need to shift from its current focus on efficiency, towards a greater emphasis on resilience and sustainability. ‱ Second, a more centralised governance to address health emergencies is needed. ‱ Third, Europe should create a centre for the prevention of large-scale risks. ‱ Fourth, digital technologies, if handled with care, can be an important part of both a mitigation and a response strategy. ‱ Fifth, Europe should improve its science advice and communication functions. Finally, there are many ways to pursue enhanced resilience and responsiveness, but not all of them are compatible with sustainability and democratic values. The challenge is to find an adequate policy mix, which safeguards individual rights and liberties, protects the economy, and at the same time strengthens government preparedness for cases of epidemics and pandemics

    Radiative heat transfer between two dielectric nanogratings in the scattering approach

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    We present a theoretical study of radiative heat transfer between dielectric nanogratings in the scattering approach. As a comparision with these exact results, we also evaluate the domain of validity of Derjaguin's Proximity Approximation (PA). We consider a system of two corrugated silica plates with various grating geometries, separation distances, and lateral displacement of the plates with respect to one another. Numerical computations show that while the PA is a good approximation for aligned gratings, it cannot be used when the gratings are laterally displaced. We illustrate this by a thermal modulator device for nanosystems based on such a displacement

    Phosphorus retention capacity in red ferralitic soil

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    In this study the main physical-chemical characteristics of red ferralitic soil to use as substrate in subsurface wetlands was determined. The P-removal was evaluated in a short-term isotherm batch experiment and in a column percolation experiment. The acid characteristic and high content of iron minerals in the red ferralitic soil facilitated the phosphorus removal. Also the sorption isotherms at two different temperatures were obtained. The results showed that the sorption capacity increases with an increase in solution temperature from 25 to 35 degrees C. The experimental data were fitted to Langmuir and Freundlich models, having a better fit to the Freundlich isotherms. The maximum P-sorption capacities estimated using the Langmuir isotherm were 0.96 and 1.13 g/kg at 25 and 35 degrees C respectively. Moreover a column experiment was carried out at two different flows. Sequential extractions of the phosphorus-saturated soil indicated that phosphorus is mainly bound with iron or aluminum minerals. The results have demonstrated a good potential for red ferralitic soil for phosphorus removal from urban wastewater

    Estimation of Nonparametric Functions in Simultaneous Equations Models, with an Application to Consumer Demand

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    We present a method for consistently estimating nonparametric functions and distributions in simultaneous equations models. This method is used to identify and estimate a random utility model of consumer demand. Our identification conditions for this particular model extend the results of Houthakker (1950), Uzawa (1971) and Mas-Colell (1977), where a deterministic utility function is uniquely recovered from its deterministic demand function.

    Bounds on Cubic Lorentz-Violating Terms in the Fermionic Dispersion Relation

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    We study the recently proposed Lorentz-violating dispersion relation for fermions and show that it leads to two distinct cubic operators in the momentum. We compute the leading order terms that modify the non-relativistic equations of motion and use experimental results for the hyperfine transition in the ground state of the 9Be+{}^9\textrm Be^+ ion to bound the values of the Lorentz-violating parameters η1\eta_1 and η2\eta_2 for neutrons. The resulting bounds depend on the value of the Lorenz-violating background four-vector in the laboratory frame.Comment: Revtex 4, four pages. Version to match the one to appear in Physical Review
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