Can you hear the Planck mass?

For the Laplacian of an n-Riemannian manifold X, the Weyl law states that the k-th eigenvalue is asymptotically proportional to (k/V)2/n, where V is the volume of X. We show that this result can be derived via physical considerations by demanding that the gravitational potential for a compactification on X behaves in the expected (4+n)-dimensional way at short distances. In simple product compactifications, when particle motion on X is ergodic, for large k the eigenfunctions oscillate around a constant, and the argument is relatively straightforward. The Weyl law thus allows to reconstruct the four-dimensional Planck mass from the asymptotics of the masses of the spin 2 Kaluza-Klein modes. For warped compactifications, a puzzle appears: the Weyl law still depends on the ordinary volume V, while the Planck mass famously depends on a weighted volume obtained as an integral of the warping function. We resolve this tension by arguing that in the ergodic case the eigenfunctions oscillate now around a power of the warping function rather than around a constant, a property that we call weighted quantum ergodicity. This has implications for the problem of gravity localization, which we discuss. We show that for spaces with Dp-brane singularities the spectrum is discrete only for p = 6, 7, 8, and for these cases we rigorously prove the Weyl law by applying modern techniques from RCD theory

Harmonic functions and gravity localization

In models with extra dimensions, matter particles can be easily localized to a 'brane world', but gravitational attraction tends to spread out in the extra dimensions unless they are small. Strong warping gradients can help localize gravity closer to the brane. In this note we give a mathematically rigorous proof that the internal wave-function of the massless graviton is constant as an eigenfunction of the weighted Laplacian, and hence is a power of the warping as a bound state in an analogue Schr\"odinger potential. This holds even in presence of singularities induced by thin branes. We also reassess the status of AdS vacuum solutions where the graviton is massive. We prove a bound on scale separation for such models, as an application of our recent results on KK masses. We also use them to estimate the scale at which gravity is localized, without having to compute the spectrum explicitly. For example, we point out that localization can be obtained at least up to the cosmological scale in string/M-theory solutions with infinite-volume Riemann surfaces; and in a known class of N = 4 models, when the number of NS5- and D5-branes is roughly equal.Comment: 43 pages, 2 figure

Triple or dual therapy for HCV-1 naive patients? Optimizing selection tools

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The role of the internal heat gains for artificial lighting on the energy performance of buildings

This paper aims to propose a procedure for calculating the energy performance indexes of buildings considering the seasonality of internal gains due to artificial lighting with a monthly quasi-steady-state energy balance. The proposed methodology evaluates the heat gains due to the integrated natural-artificial lighting system with the Lighting Energy Numerical Indicator (LENI). For the evaluation of buildings’ global energy performance and for some energy services, this contribution cannot be considered constant annually as depend strongly by climate conditions. The effect of daylighting, type of light sourcesluminaires, building orientation and shading devices could influence lighting contribution of the internal heat gains. Then, the proposed methodology evaluates the internal heat gains with monthly energy balances. This methodology was applied to the case study of the "Brancaccio" retirement home in Matera (IT) for which the values of the energy performance indexes were compared with the standard normative approach using constant internal heat gains. The results of this work underline the importance of performing a detailed analysis that considers the availability of natural light in the different months of the year, the efficiency of the different lighting systems and their power installed per unit of area as a function of the lighting comfort requirements in the different types of environments

Bank Competition and Financial Stability: A General Equilibrium Exposition

Summary: We study versions of a general equilibrium banking model with moral hazard under either constant or increasing returns to scale of the intermediation technology used by banks to screen and/or monitor borrowers. If the intermediation technology exhibits increasing returns to scale, or it is relatively efficient, then perfect competition is optimal and supports the lowest feasible level of bank risk. Conversely, if the intermediation technology exhibits constant returns to scale, or is relatively inefficient, then imperfect competition and intermediate levels of bank risks are optimal. These results are empirically relevant and carry significant implications for financial policy

Evaluation of LENI in a case study of a retirement home

This work aims to propose a case study for the calculation of the energy performance of lighting systems in a retirement home. The proposed methodology evaluates the energy consumption of lighting systems in the presence of daytime lighting and occupancy control strategies with the Lighting Energy Numerical Indicator (LENI). The effect of natural light, the LED sources, the external obstructions, as well as building orientation and shading systems, can influence the energy consumption of the lighting systems. The case study analysed was the “Brancaccio retirement home” located in Matera (Southern part of Italy). The results of this work refer to both annual and monthly energy consumptions, and underline how important it is to evaluate the amount of energy throughout the year in the presence of control systems, given the considerable monthly variation. Furthermore, the LED source is able to significantly reduce energy consumption compared to fluorescent lamps, and this energy saving can be further increased in the presence of control systems

Systemic Risks and the Macroeconomy

This paper presents a modeling framework that delivers joint forecasts of indicators of systemic real risk and systemic financial risk, as well as stress-tests of these indicators as impulse responses to structural shocks identified by standard macroeconomic and banking theory. This framework is implemented using large sets of quarterly time series of indicators of financial and real activity for the G-7 economies for the 1980Q1-2009Q3 period. We obtain two main results. First, there is evidence of out-of sample forecasting power for tail risk realizations of real activity for several countries, suggesting the usefulness of the model as a risk monitoring tool. Second, in all countries aggregate demand shocks are the main drivers of the real cycle, and bank credit demand shocks are the main drivers of the bank lending cycle. These results challenge the common wisdom that constraints in the aggregate supply of credit have been a key driver of the sharp downturn in real activity experienced by the G-7 economies in 2008Q4- 2009Q1

The Bank Tailored Integrated Rating

We develop a banks specific integrated rating, tailored incorporating the various heterogeneity dimensions characterizing financial institutions (see Mantovani et al. 2013 and 2014 regarding the heterogeneity risk analysis in corporate firms), named bank tailored integrated rating (BTIR). The approach is inherently coherent with the challenging frontier of forecasting tail risk in financial markets (De Nicolò and Lucchetta, J Appl Econ 32(1):159–170, 2017) since it considers the downside risk in the theoretical framework. The innovation consists in using the integrated rating (IR) with the pre-selection of the variables through a statistical procedure that takes into account the characteristics of risk and greater heterogeneity of the banks. A Vector Autoregressive Model (VAR) is only a first simple application proposal

Analytical validation and clinical application of rapid serological tests for sars-cov-2 suitable for large-scale screening

Recently, large-scale screening for COVID-19 has presented a major challenge, limiting timely countermeasures. Therefore, the application of suitable rapid serological tests could provide useful information, however, little evidence regarding their robustness is currently available. In this work, we evaluated and compared the analytical performance of a rapid lateral-flow test (LFA) and a fast semiquantitative fluorescent immunoassay (FIA) for anti-nucleocapsid (anti-NC) antibodies, with the reverse transcriptase real-time PCR assay as the reference. In 222 patients, LFA showed poor sensitivity (55.9%) within two weeks from PCR, while later testing was more reliable (sensitivity of 85.7% and specificity of 93.1%). Moreover, in a subset of 100 patients, FIA showed high sensitivity (89.1%) and specificity (94.1%) after two weeks from PCR. The coupled application for the screening of 183 patients showed satisfactory concordance (K = 0.858). In conclusion, rapid serological tests were largely not useful for early diagnosis, but they showed good performance in later stages of infection. These could be useful for back-tracing and/or to identify potentially immune subjects