US PRICE INDICES AND THE EXCHANGE RATE: ARE RECREATIONAL PRODUCTS DIFFERENT?

The paper analyses the cointegration relationships and the causal links between the exchange rate of the US Dollar, on the one side, and different price indices of US products on the other side. Data are of monthly frequency and cover a period of two or three decades. We show that the exchange rate cointegrate with the Consumer Price Index and with the prices indices of several agricultural, manufactured and service goods; moreover a one-direction causal link is present, running from price to exchange rate. On the opposite, cointegrating relationships between exchange rate and price indices do not exist in the case of recreational products with �cultural� content. Tentative theoretical explanations are proposed.Price Index; Exchange Rate, Cointegration, Causality

Price of recreational products and the exchange rate: an empirical investigation on US data

The paper analyses the cointegration relationships and the causal links between the exchange rate of the US Dollar, on the one side, and different price indices of US products on the other side. Data are of monthly frequency and cover a period of two or three decades. We show that the exchange rate cointegrate with the Consumer Price Index and with the prices indices of several agricultural, manufactured and service goods; moreover a one-direction causal link is present, running from price to exchange rate. On the opposite, cointegrating relationships between exchange rate and price indices do not exist in the case of recreational products with “cultural” content. Tentative theoretical explanations are proposed.Price Index; Exchange Rate; Cointegration; Causality

Managerial incentive and the firms’ propensity to invest in product and process innovation

We study the product and process innovation choice of firms in which a managerial incentive à la Vickers (1985) is present. Taking a two-stage dynamic game approach, we show that managerial firms are led to over-invest in process innovation, as compared to standard profit-maximising firms, while they under-invest in product innovation. The reason is that process innovation allows to decrease cost, and this is consistent with a convenient increase in the production level. On the opposite, product innovation allows increasing price, which is in contrast with the taste for output expansion embodied in the objective function of firms run by managers. Preliminary empirical evidence on Italian companies suggests that in fact the managerial nature of firm associates with significantly smaller efforts in product innovation while the effect on process innovation is positive but non-significant.Process innovation; Product innovation; R&D; Managerial incentive

Managerial incentive and the firms' propensity to invest in product and process innovation

We study the product and process innovation choice of firms in which a managerial incentive à la Vickers (1985) is present. Taking a two-stage game approach, we show that managerial firms are led to over-invest in process innovation, as compared to standard profit-maximising firms, while they under-invest in product innovation. The reason is that process innovation allows to decrease cost, and this is consistent with a convenient increase in the production level. On the opposite, product innovation allows increasing price, which is in contrast with the taste for output expansion embodied in the objective function of firms run by managers. Preliminary empirical evidence on Italian companies suggests that in fact the managerial nature of firm associates with significantly smaller efforts in product innovation while the effect on process innovation is positive but non-significant

Sampling Nambu-Goto theory using Normalizing Flows

Effective String Theory (EST) is a non-perturbative framework used to describe confinement in Yang-Mills theory through the modeling of the interquark potential in terms of vibrating strings. An efficient numerical method to simulate such theories where analytical studies are challenging is still lacking. However, in recent years a new class of deep generative models called Normalizing Flows (NFs) has been proposed to sample lattice field theories more efficiently than traditional Monte Carlo methods. In this contribution, we show a proof of concept of the application of NFs to EST regularized on the lattice. Namely, we introduce Physics-Informed Stochastic Normalizing Flows and we use them to sample the Nambu-Goto string action with two goals: use the known analytical results of this theory as a benchmark and demonstrate the efficiency of our method in obtaining new results of physical interest and in particular in providing a numerical proof for a conjecture regarding the width of the string.Comment: 7 pages, 3 figures, contribution for the 40th International Symposium on Lattice Field Theory (Lattice 2023), July 31st - August 4th, 2023, Fermi National Accelerator Laborator

Stochastic normalizing flows as non-equilibrium transformations

Normalizing flows are a class of deep generative models that provide a promising route to sample lattice field theories more efficiently than conventional Monte Carlo simulations. In this work we show that the theoretical framework of stochastic normalizing flows, in which neural-network layers are combined with Monte Carlo updates, is the same that underlies out-of-equilibrium simulations based on Jarzynski's equality, which have been recently deployed to compute free-energy differences in lattice gauge theories. We lay out a strategy to optimize the efficiency of this extended class of generative models and present examples of applications.Comment: 1+28 pages, 8 figures; v2: 1+29 pages, 8 figures, added references, discussion in section 4 improved; v3: 1+31 pages, 9 figures, added references, discussion in section 4 expanded, matches published versio

Stochastic normalizing flows for lattice field theory

Stochastic normalizing flows are a class of deep generative models that combine normalizing flows with Monte Carlo updates and can be used in lattice field theory to sample from Boltzmann distributions. In this proceeding, we outline the construction of these hybrid algorithms, pointing out that the theoretical background can be related to Jarzynski's equality, a non-equilibrium statistical mechanics theorem that has been successfully used to compute free energy in lattice field theory. We conclude with examples of applications to the two-dimensional $\phi^4$ field theory.Comment: 9 pages, 4 figures, contribution for the 39th International Symposium on Lattice Field Theory, 8th-13th August, 2022, Bonn, German

ET-1 plasma levels, choroidal thickness and multifocal electroretinogram in retinitis pigmentosa

Aim To assess the relationship between both photoreceptor function and choroidal thickness and endothelin-1 (ET-1) plasma levels in patients with early stage retinitis pigmentosa (RP). Main methods We compared 24 RP patients (14 males and 10 females), 25 to 42 years of age (mean age: 34 ± 7 years) with 24 healthy controls (12 males and 12 females) aged between 28 and 45 years (mean 36 ± 6.8 years). All patients underwent visual field test, electroretinogram and multifocal-electroretinogram and choroidal thickness measurement by using spectral domain optical coherence tomography. Key findings RP patients had a visual acuity of 0.95, a mean defect of the visual field of − 7.90 ± 1.75 dB, a pattern standard deviation index of 6.09 ± 4.22 dB and a b-wave ERG amplitude of 45.08 ± 8.24 μV. Notably RP subjects showed significantly increased ET-1 plasma levels and reduced choroidal thickness compared with controls: respectively, 2.143 ± 0.258 pg/ml vs. 1.219 ± 0.236 pg/ml; p < 0.002 and 226.75 ± 76.37 μm vs. 303.9 ± 39.87 μm; p < 0.03. Spearman's correlation test highlighted that the increase of ET-1 plasma levels was related with the decrease of choroidal thickness (r = − 0.702; p < 0.023) and the increase of implicit time in both ring 2 (r = − 0.669; p < 0.034) and ring 3 (r = − 0.883; p < 0.007) of mfERG. Significance Increased ET-1 plasma levels may play a key role in the impairment of retinal and choroidal blood flow due to the vasoconstriction induced by ET-1. This could lead to worsening of the abiotrophic process of the macular photoreceptors

Price of recreational products and the exchange rate: an empirical investigation on US data

The paper analyses the cointegration relationships and the causal links between the exchange rate of the US Dollar, on the one side, and different price indices of US products on the other side. Data are of monthly frequency and cover a period of two or three decades. We show that the exchange rate cointegrate with the Consumer Price Index and with the prices indices of several agricultural, manufactured and service goods; moreover a one-direction causal link is present, running from price to exchange rate. On the opposite, cointegrating relationships between exchange rate and price indices do not exist in the case of recreational products with “cultural” content. Tentative theoretical explanations are proposed

Price of recreational products and the exchange rate: an empirical investigation on US data

The paper analyses the cointegration relationships and the causal links between the exchange rate of the US Dollar, on the one side, and different price indices of US products on the other side. Data are of monthly frequency and cover a period of two or three decades. We show that the exchange rate cointegrate with the Consumer Price Index and with the prices indices of several agricultural, manufactured and service goods; moreover a one-direction causal link is present, running from price to exchange rate. On the opposite, cointegrating relationships between exchange rate and price indices do not exist in the case of recreational products with “cultural” content. Tentative theoretical explanations are proposed